Solid State Ionic materials play an important role as technology enablers. Connection between the materials science in general and the sustainable development of humanity, and challenges-, responsibilities-, and opportunities- available for everyone concerned will be the focus of discussion.
Energy, Environment and Health Care are some of the many issues that determine the sustainable development of humanity. The impact of human being on the planet & our immediate concerns, need for social engagement, and societal education apart from technical development will be highlighted. The need for embracing the Green Economy and the balance between the “natural” and “built” environments will be emphasised.

The use of lithium metal anodes brings great opportunities for constructing high-energy batteries to meet the ever-growing energy demand due to its high volumetric and gravimetric energy densities. Garnet-type electrolyte (LLZO) has attracted tremendous attentions owing to its high ionic conductivity, good electrochemical/stability, and high chemical stability against Li metal. However, there are still some obstacles restricting their practical applications in the solid state batteries, such as low density and abnormal grain growth of bulk electrolytes, high electrolyte/electrode interface impedance, side chemical reaction and low wettability between lithium metal and the ceramic electrolyte as well as lithium dendrite growth at interface. A variety of approaches have been adopted to suppress the nucleation of lithium dendrite at the non-uniform Li/SSEs interface and their propagation along voids or grain boundaries (GBs) of the ceramics. In this presentation, various strategies to realize high density ceramic electrolytes by optimizing sintering atmosphere, designing the grain boundary, lowering interfacial impedance and enhancing interface kinetics by alloying of lithium metal, elastic modification, or sustained release-driven protective interlayer, and so on will be presented.

Lithium-ion batteries have aided the wireless revolution, and they are on the verge of transforming the society through electrification of the transportation sector and efficient storage of electricity produced from renewable energy sources like solar and wind. However, their widespread adoption for these large-scale applications requires optimization of cost, cycle life, safety, energy density, power density, and environmental impact, all of which are directly linked to severe materials challenges. Among them, cost and sustainability will be the single dominant factor as the battery market is rapidly expanding. This presentation will focus on the development of sustainable, supply-chain-free, next-generation battery chemistries. Strategies and approaches for progressively eliminating expensive and scarcely available cobalt, followed by eliminating nickel, and ultimately any mined metal, including lithium, will be discussed. As an example, the progress on cobalt-free cells, cobalt- and nickel-free cells, lithium-sulfur cells, and sodium-sulfur cells will be presented. The challenges of bulk and surface instability, chemical crossover during charge-discharge cycling, dynamics and stabilization of lithium or sodium plating and striping, and enhancing the charging rate will be discussed. Approaches to overcome the challenges and the use of advanced characterization methodologies to develop an in-depth understanding will be presented.

Much attention is currently being paid to solid electrolytes and fast electrodes. Targeted developments are required for practical applications. Beyond high ionic mobility, many other properties must be taken into account.Only suitable combinations of materials with well selected kinetic and thermodynamic properties of both the electrolytes and electrodes are relevant. These requirements and an insight into the fundamental processes of cell operation will be discussed in terms of the various electrical and thermodynamic potentials. Electrons are often neglected, but play a most important role in the performance for both solid electrolytes and electrodes. Further, solid state electrochemical techniques will be discussed for enhancing and optimizing the search for suitable materials combinations for practical applications. The general considerations are illustrated using examples, particularly with regard to the targeted development of all-solid state batteries.

Polymer electrolytes is regarded as the essential component separating the anode and cathode in any electrochemical devices.It is an undeniable fact that ionic conductivity of polymer electrolytes plays a crucial role in ensuring the performance of electrochemical cells. Therefore, this talk focuses on the conductivity aspect of polymer electrolytes in order to gain a better insight and understanding on the ionic transport properties. From conductivity data, several important parameters such as number density of mobile ions, ionic mobility and diffusion coefficient of ions can be determined.In order to verify the results, these transport parameters have also been obtained via deconvolution of fourier transform infrared (FTIR) spectra of the electrolytes. Many polymer electrolytes have been developed in our laboratory but consideration is focused on polyacrylonitrile (PAN), methylcellulose (MC) and poly(vinylidene fluoride) (PVdF)as polymer host with lithium bis(oxalato)borate (LiBOB) salt for ionic conduction.In this talk, the ionic transport of these polymer electrolytes will be deliberated.

Lithium (Li)-ion batteries have been the cornerstone for powering modern electronic and electrical devices. The exponential growth in energy demand, driven by technological advancements and compounded by concerns about the critical materials supply chain, necessitates more robust, sustainable, and reliable energy storage devices. With promising materials design and development efforts gaining momentum, there is a growing quest for alternatives, such as sodium and multivalent ion-based battery technologies. Our team is actively involved in designing transformative materials for batteries, integrating artificial intelligence for material discovery across cathodes, anodes, electrolytes, and designer interfaces. In this presentation, I will discuss our team's efforts in constructing batteries utilizing multivalent ions (such as Mg2+) and also alkali ion-conducting solid-state electrolytes, addressing the critical issue of the materials supply chain in our pursuit of sustainable energy storage solutions.

The rapid depletion of non-renewable fossil resources is posing an imminent threat to the energy and supply of fine chemicals that are vital to the global economy. Currently, efforts are being undertaken at an accelerated pace to develop technologies that would help us deal with the disastrous consequences. We have been working in the areas of biomass conversion to renewable fuels/chemicals as well as the production of hydrogen through the electrocatalytic splitting of water using non-noble metals. In both of these areas, there is a dire need to develop cost-effective materials to increase the efficiency of the processes. We have been exploring the use of anionically modified molybdenum oxides and phosphides for the efficient splitting of water in both acidic and alkaline conditions. The presentation will summarize our findings and the opportunities for exploring inorganic materials for the production of value-added chemicals and fuels.

Proton conductivity in phosphate glasses was first discovered by Namikawa et al. in 1966, and its origin was subsequently clarified by Abe et al. Since then, their proton conductivity has been intensively investigated for applications in electrochemical devices such as fuel cells. However, conventional phosphate glasses could not retain proton carriers at temperatures above 250 °C. This is because the protons in glass exist predominantly as molecular water, which is readily released outside the glass at high temperatures. The limitation had recently been overcome by a proton injection method into phosphate glasses termed as alkali-proton substitution (APS), where the sodium ions in glass are electrochemically substituted with protons at high temperature (Fig. 1(a)). By using APS, a variety of glasses have been found that exhibit high proton conductivity (Fig. 1(b)). For examples, 36HO_1/2–4NbO_5/2–2BaO–4LaO_3/2–4GeO₂–1BO_3/2–49PO_5/2 and 25HO_1/2–3MgO– 7DyO_3/2–3GeO₂–62PO_5/2 glasses have high proton conductivity of 2 mScm−1 at 300°C and 4 mScm^–1 at 550 °C, respectively. This talk will introduce APS and review recent progress in the exploring highly proton-conducting glasses using APS.

Solid-state Li batteries are expected to serve as next-generation energy storage systems due to their safety, reliability, and high energy densities.However, a significant challenge lies in the ion dynamics in the grain boundaries of solid electrolytes. The oxide-based solid electrolytes have achieved ionic conductivities of the order of 10⁻³ S cm⁻¹ , internal resistance of oxide-based solid-state batteries is still highdue to high interfacial resistance at grain boundaries.Previously, the analysis of ion dynamics has focused mainly on the average ionic conductivity obtained using impedance spectroscopy (IS). The bulk diffusion coefficient can be obtained using pulsedfield gradient nuclear magnetic resonance (PFG-NMR) spectroscopy [1].In addition, we have recently developed methods to determine the diffusion coefficient of Li⁺ ions by secondary ion mass spectrometry (SIMS).
In this study, these methods were applied to polycrystalline solid electrolytes, La_0.57Li_0.29TiO₃(LLTO). The Li diffusion coefficient of LLTO has been evaluated over a wide range of time scales and temperatures using various experimental techniques(Fig. 1). The grain boundary diffusion is visualized by isotope-exchange experiment using time-of-flight(TOF) SIMS analysis [4]. The relationship between the crystal structure, nanodomains, and grain boundaries of LLTO and the diffusion of lithium ions was experimentally clarified.The conductivity diffusion coefficients and bulk NMR diffusion coefficients were in good agreement, with Haven ratios close to unity.The SIMS methods elucidate the bottleneck of ion transfer in the interface and may contribute to improving the performance of solid-state batteries.

Magnesium-ion batteries have emerged as promising alternatives to conventional lithium-ion batteries due to the low cost and abundance of magnesium resources. The exploration of magnesium-ion (Mg⁺⁺) conducting novel materials is paving the way for the development of “Mag-ionics” leading to the next-generation energy storage systems. However, their practical implementation faces challenges related to the suboptimal development of efficient electrolytes.
This presentation focuses on the exploration and characterization of selected magnesium ion-conducting polymer gel electrolytes tailored for Mg++ ion battery applications. Various polymer matrices, such as polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), or their blends, have been investigated to form gel electrolytes, incorporating magnesium salts and plasticizers. Following polymer gel electrolyte systems: PEO/Ionic Liquid/Mg(Tf)₂, PAN /Mg (ClO₄)₂ , PVdF‐HFP/ Al₂O₃/Mg(Tf)₂ and PEO/TiO₂/Mg(BH₄)₂ will be discussed as representative examples. These electrolytes are developed to enhance ionic conductivity while ensuring mechanical robustness and compatibility with magnesium electrodes. Studies on these polymer electrolytes have focused on the physicochemical characteristics of electrolytes, such as their ionic conductivity, electrochemical stability, mechanical strength, and compatibility with Mg⁺⁺ ions. Techniques such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and scanning electron microscopy (SEM) are employed for comprehensive characterization. Furthermore, the electrochemical performances of Mg++ ion batteries employing these polymer gel electrolytes are assessed through galvanostatic charge-discharge cycling and cyclic stability tests. The presentation also discusses the potential applications of these electrolytes in practical Mg-ion battery systems. The outcomes of these investigations demonstrate the viability of magnesium ion-conducting polymer gel electrolytes as promising candidates for Mg++ ion batteries.

Molecular crystals are attracting attention as a new candidate for solid electrolytes. In molecular crystalline electrolytes, ionic conduction paths are constructed by the ordered arrangement of lithium salt and molecules in the crystal lattice. Li-ion conduction takes place through this ionic conduction path. Previously, we have reported a molecular crystalline electrolyte, Li(FSA)(SN)₂, composed of Li{N(SO2F)₂} (LiFSA) and succinonitrile (SN).[1] This electrolyte exhibits high ionic conductivity of 10^-4 S cm^-1 at room temperature and a high Li-ion transference number (t_Li⁺) of 0.95. However, its electrochemical stability was limited to about 4 V vs. Li/Li⁺.
Therefore, in this study, we attempted to prepare a molecular crystal electrolyte composed of Li{N(SO₂CF₃)₂} (LiTFSA), an analogue of LiFSA, and SN to expand the potential window. We found that the reaction between LiTFSA and SN proceeds at a molar ratio of 2:3 to give Li₂(TFSA)₂(SN)₃. The crystal structure of Li₂(TFSA)₂(SN)₃ was determined by single crystal X-ray structure analysis (Figure 1). Furthermore, we revealed that the obtained Li₂(TFSA)₂(SN)₃ exhibits moderate Li-ion conductivity of about 10^-5 S cm^-1 at room temperature, high t_Li⁺ values of 0.98, and excellent electrochemical stability of more than 5 V vs. Li/Li⁺ .

The bond fluctuation model of superionic conductors proposed by the author, predicts that there must be a close relationship between the electronic polarizability and the ionic conduction in solids. Guided by this model, we have studied the correlation between the nonlinear optical constants and the ion transport properties in crystalline and glassy ion conducting materials. The results of these studies indicated that the nonlinear optical constant increases with the increase of the ionic conductivity. In a recent study on supercooled liquids, we have noted that the optical properties could be also related with structural relaxations. All these notions suggest the possibility that ionic conductors could be also used as optical materials. However, there are only few studies on the subject. In order to understand deeply the obtained behaviour and promote their application, further studies are required.In the present contribution, after giving a short review on previous works, a model to understand why the ionic migration correlates with the nonlinear optical constant will be presented.

Salt-In-Polymer-Electrolytes (SIPEs), i.e. polymer electrolytes where the salt concentration is lesser than the polymer host, are dominating the commercial energy device market. Still there are a few problems (especially poor cationic transference and slow ion transport) related to SIPEs which need to be addressedto enhance energy device performance. While studying SIPEs it has been observed that when the salt concentration is increased, after a certain concentration ion-pairs (or ion-clusters) are formed resulting in decreased conductivity and hence limiting the usable salt concentration. In the 1990s Angel and coworkers proposed that further increasing the salt concentration after a certain threshold concentration these ion-clusters are well connected throughout the matrix which leads to change of ion transport mechanism. After this the ion transport is decoupled from polymer segmental motion and it starts diffusing the through ion cluster which is much faster and also enhances the cationic transference number.Having higher salt concentration than polymer host, these electrolytes are known are known as Polymer-In-Salt-Electrolytes (PISEs) and because of their properties they are also called rubbery polymerelectrolytes. PISEs synthesis is a challenge because the high salt concentration leads to salt recrystallization and hence resulting in poor electrochemical and poor mechanical properties. For this reason, salt selection becomes very important and only those salts and/or salt mixtures that are found to be successful are in rubbery state at room temperature. Polymer host also needs special attention because in PISEs, host should have some important properties i) its interaction with salt should not be too strong so that polymer segmental motion decoupled ion transport can be achieved, ii) it should have loose bond structure so that it can accommodate ion-cluster formation iii) it should have capability of salt dissociation and keep the matrix intact even at high salt concentration. These are the reasons why hosts successful in SIPEs are not good for PISEs. Few PISEs reported till date reached to minimum desired conductivity (~.0001S/cm) in film form, still they could be not tested for commercial application because of high cost, poor mechanical properties and ageing effects. Our group is working on getting PISEs having good electrochemical properties and satisfying 3Es (Economical, Environment benign and Easy to handle for device design) conditions required for commercial application. Using a variety of permutation combinations of salts, starch and crosslinkers, it has been proved that crosslinked starches are a possible host which can be mixed with any salt without requiring any rubbery state. This synthesis protocol does not require any sophisticated instruments and/or any complicated chemical procedure. The reason for crosslinked starch being so successful is the dominance of hydrogen bonding in its structure. The hydrogen bonding can vary in strength and length and hence easily accommodate ion-cluster formation and also it makes a bridge between salt ions and starch by keeping the matrix intact and flexible. All these indicates, if explored in detail, crosslinked starch or host having similar chemical structure/properties could lead to commercial PISEs.

The lithium-sulfur (Li-S) battery is considered an alternative to Li-ion batteries due to its large theoretical capacity (1675 mAh g^-1 ) and high energy density (2600 Wh Kg^-1 ). However, polysulfide shuttling, self-discharge, lithium dendrite growth, and thermal hazards transcend the lapse of commercialization of lithium-sulfur batteries. Rectifying these issues can help achieve better storage capacity. As of now, remarkable attempts have been made to explore battery configurations and components, electrode structure, electrolyte composition, and separator modifications. Modified or functionalized separators are incredibly viable in addressing the issues mentioned earlier. However, modifying the separators helps suppress the shuttling of polysulfides during discharging by holding the Sn^-2 (polysulfides) in the cathode compartment by various trapping effects without minimizing the usage of active material. Various high conductive functionalized carbon (carbon black, Super P Timal, CNTs, MWCNTs, SWCNTs, etc.), metal oxides (TiO₂, Fe₃O₄, Al₂O₃, etc.) and polymers (Inorganic and Organic) have been tested as the surface modifiers on the conventional separators for the alleviation of polysulfides, which helps to conquer high energetic Li-S batteries. Among these, biomass-derived activated porous carbon is an alternative material for physically absorbing the polysulfide intermediates in Li–S batteries. Therefore, the current presentation explores the usage of porous carbon derived from various biomasses and its critical role in arresting polysulfide shuttling to obtain high-energy and stable Li-S batteries.

SOC (Solid Oxide Cell) demonstrates promising potential for the mutual conversion between H2 and electrical energy, making it highly relevant in the context of the increasing intermittent renewable power generation. However, the widespread commercialization of SOCs still faces challenges related to efficiency and stability. In this study, the industrial-size SOC is tested and analysed. By quantitatively decomposing over potentials in fuel cell mode and electrolysis mode, it is observed that thegas diffusion over potential in fuel electrodeis the dominant factor influencing performance at high current densities and contributing to the asymmetry in over potentials between fuel cell mode and electrolysis mode. Stability tests are conducted under high fuel utilization or high steam utilization conditions, revealing that the degradation mainly stems from non-percolating Ni particles within the fuel electrode functional layer in localized areas with high steam pressure. Based on the performance and stability analyses, an optimization approach for the fuel electrode support layer is proposed. This involves increasing the porosity of support layer and replacing its framework with a mechanically stronger 3YSZ instead of 8YSZ. In fuel cell mode, the improved cell achieves an efficiency of 52.1% and a power output of 30.0 W at 40 A using H2 fuel, while in electrolysis mode, it achieves a steam utilization of 84.2% and a hydrogen production rate of 18.2 L/min at 1.3 V. The proportion of non-percolating Ni at the outlet is effectively reduced, resulting in a significant enhancement in the stability of both fuel cell mode and electrolysis mode.

Solid electrolytes for all-solid-state batteries (ASSBs) with superior energy density have to combine fast conductivity with low density. While the mass of the “separator” electrolyte can be minimized by reducing its thickness, most of the electrolyte within energy-dense ASSBs will be the catholyte. Additional constraints for ion conductors include of course electrochemical and electromechanical compatibility, as well as interface wettability with the active materials and ideally elasticity. Two strategies to realize soft low-density electrolytes will be discussed. One involves ultrathin ceramic-in-polymer Composite Solid Electrolytes (CSEs). Optimized CSEs combining Li-doped polyacrylonitrile with ceramic fillers with and without plasticizers reach conductivities of 0.1–1 mS/cm at densities g/cm³ and retain wide electrochemical windows. Spin coating and in-situ UV-curing precursors on Li anode or cathode drastically reduces interfacial resistance. Symmetric cells cycled with up to 2 mA/cm² over 500h retain a stable overpotential and no dendrite growth is observed. LFP/SSE/Li cells achieve a maximum specific discharge capacity of 148 mAh·g^-1 and retain 89% of that after 200 cycles. Stable room temperature cycling is demonstrated for cells with a cathode loading of 6 mg·cm^-2 . Strong binding and three-dimensional architecture of the in situ-formed interfaces is crucial for cycling stability.
An alternative strategy explores the correlation between ionic conductivity, density and glass forming ability in glass-ceramic oxyhalides, which - in view of their oxidation stability - are particularly suitable as catholytes. The recent report of conductivities >10 mS/cm³ in LiMOCl4 (M=Nb, Ta) exemplifies the strong potential of the hardly explored oxyhalides. Our redetermination of LiNbOCl4 (density 2.7 g cm^-3 ) finds a structure consistent with DFT minimizations. Molecular dynamics simulations utilizing our bond-valence-based EAM-type force field soft BV-EAM reveal the ion transport mechanism and the effect of the rotational mobility of (MOCl₄ – )n entities there in.

Renewable energy sources are critical for decreasing the growing greenhouse gas emissions. They play a vital role in the transition to a decarbonized economy. Because renewable sources such as solar and wind are intermittent, reliable energy storage and conversion systems are crucial for their utilization. Fuel cells and batteries can be implemented to store energy from renewable sources for transport and grid-scale applications. For example, grid-scale batteries based on the lithium ion and vanadium redox flow concept can store excess generation from renewable energies. Solid oxide cells operating as electrolyzers can be coupled with renewable energy sources to produce clean hydrogen which can be used for electricity generation. High-energy-density metal batteries can accelerate electrification in both transport and peak shaving applications. In this talk, development of solid state materials for advanced fuel cells and batteries will be presented.

X-ray interacts with the inner-shell electrons in atoms, causing phenomena specific to materials and their constituent elements, for instance, diffraction, scattering, absorption and emission. Therefore, analyses using X-ray are indispensable tools in the field of material sciences. In particular, X-ray with energies of several keV or higher can easily penetrate substances composed mainly of light elements (e.g. electrolyte solutions, gases), enabling operando analysis of various devices. In recent years, the use of synchrotron X-ray, which has high brightness, a wide usable energy range and the ability to arbitrarily select the energy, makes advanced analyses possible, such as high spatial resolution, high time resolution and multi-dimensional measurements. We believe that such synchrotron X-ray analyses together with conventional electrochemical measurements are effective for a deeper understanding of various phenomena occurring in solid state ionics devices including batteries and fuel cells. In this presentation, we introduce one of our developed operando analytical technique, namely CT-XAFS. This technique combines computed tomography (CT), which can nondestructively observe three-dimensional structures, and X-ray absorption fine structure (XAFS), which can evaluate electronic structure and chemical state of investigated materials and elements. We applied CT-XAFS to three-dimensional operando analysis of reaction distribution in all-solid-state battery electrodes. It was demonstrated that operando CT-XAFS is useful to investigate reaction propagation, rate-determining factors, degradation, etc. in practical composite battery electrodes.

Owing to environmental concerns, the legislators around the world unanimously adopt government policies with a focus to eradicate IC engine transport vehicles while promoting electric vehicles powered by advanced Li-Ion batteries with government sponsored incentive schemes. The nominal charging nature of traditional Li-Ion batteries powering motor cars pose a great deal of concern for end users at charging stations. Hence, a fast charging protocol supported by software controlled active BMS has been introduced by several OEMs (Tesla for example). Nevertheless, such a fast charging approach does inadvertently compromise safety as well as health of the battery. Amongst many technologies developed by Inventus Battery Energy Technologies (inventus.in), one of its flagship technologies namely Capattery, a hybrid device having three electrodes Carbon/LTO/LixFePO₄ (M= transition metal oxide) as a single pouch cell which acts as a supercapacitor (Carbon/LTO couple) while charging and discharges like a battery cell (LTO/LixFePO₄) that can power an electric load. With its demonstrated fast charging capability, the device can be cycled for over 10,000 times with 85% charge retention. The prototype device that demonstrates great promise for its fast charging (< 15 min) without compromising safety, has reached technology readiness level (TRL) 7. Further, we continue develop it's scale-up feasibility towards commercialization.

Lithium-ion batteries have revolutionized electric powered products because of their high energy and power density. These batteries are produced in very large quantities and are perfectly safe in normal operation. However, events involving thermal runaway, gas emissions, fire and even explosions do occur.Although such events are rare the consequences of a malfunction in one cell spreading to adjacent cells can be serious with vented gases and fumes that are flammable, explosive, and toxic. Results of abuse situations will be reviewed regarding overcharge, short circuit, overheating and fire abuse, special attention will be given to heat and gas emissions.

Dye sensitized solar cells (DSSC) are known as promising candidates as an alternative for expensive crystalline solar cell. High energy conversion efficiency is one of the most important challenges for the commercialization of DSSC in the huge power generation market. Though they lag behind silicon or thin film (CIGS etc.) based solar cells, but in terms of cost DSSC stands much ahead of their other counterparts. Since 1991 till date it has seen many changes and modifications in all its components and hence efficiency. According to our experience the persistent efforts have helped to achieve moderately high efficiency of DSSCs up to 13%.
Polymer electrolytes can be very well used in solar cells, including DSSCs. However, this application of polymer electrolyte is rarely explored. Though the polymer electrolyte based DSSCs face challenges such as low efficiency, stability, cost and extension to large area with its flexibility. The most common polymer electrolyte PEO:KI was reported to show efficiency ~0.017% only. However, with suitable modifications, using fillers, ionic liquids etc. the efficiency could be improved to ~7%. This talk is directed towards the review on major progress on the modification of polymer electrolytes in DSSCs for possible improvement in the energy conversion efficiency and their stability. Challenges shall be therein discussed with possibilities of open discussion for further improvement.

Lithium-sulfur batteries have been strongly advocated as next generation energy storage device due to high energy density, higher safety and lower cost. However, the problem of shuttling of lithium polysulfide is the main reason for reduced capacity and low cycle life. Different methods have been adopted to synthesize sulfur nanoparticle to reduce the dissolution of lithium polysulfide. In addition to that electrolyte modification is also needed for longer cycle. In another attempt the separators have been modified using graphene oxide and it has been found that the capacity as well as cycle life increases. In this case a stable SEI layer is also required for anode protection. The specially designed cathode structure as well as new types of electrolyte render formation of stable SEI layer on lithium anode side. The composite cathode exhibits an initial discharge capacity of ~1011mAh/g with capacity decay of 0.31% per cycles this can be cycled up to ~170 cycles. Post mortem analysis is another important aspect to study the reason behind capacity fading.

Because of excellent ionic and electronic conductivities, as well as good redox properties, perovskite oxides have become very attractive as electrode materials for solid oxide fuel cells/solid oxide electrolysis cells (SOFCs/SOECs). However, they generally show poor catalytic activity comparing with metal-based catalysts. Although perovskite oxides have stable structure, their stability is problem at high applied potential in SOEC mode. To address these problems, we proposed several promising methods, including in situ construction of hetero-structured perovskite composites; the lattice oxygen p-band center regulation of the perovskite electrocatalysts; enhancement of the oxygen ion exchange properties of perovskite electrocatalysts by tuning nanoparticles; boosting the stability of perovskites by B-site supplement mechanism; and phase transition engineering of host perovskite toward optimal exsolution-facilitated catalysts. This report mainly introduces the progress and applications of these strategies to enhance the reaction kinetics and improve the stability of perovskite electrocatalysts.

In today's world, addressing environmental challenges is an investment rather than an expense. It is our responsibility in this day and age to protect the wealth and natural beauty that we have inherited from past generations for the benefit of future generation. The significant increase in global energy consumption and the diminishing reserves of fossil fuels have spurred considerable interest in the rational development of new paradigms for renewable energy that are solely based on the idea of turning waste into that are solely based on the idea of turning waste into energy. Despite the fact that sustainable fuels potentially have higher energy densities than compressed hydrogen, the power efficiencies actually achieved with the relevant fuel cells are far lower than those of other conventional fuel cells. Direct urea fuel cells (DUFCs) and microfluidic ethylene glycol fuel cells (µDEGFCs) are deemed as potential energy conversion devices for sustainable energy generation; however, the lack of efficient fuel oxidation and oxygen reduction reaction electrocatalysts continues to be a significant obstacle to their practical utility. Accordingly, the µDEGFCs and DUFCs using 3D carbon aerogels (CAs) comprising carbon-confined bimetallic nanoparticles decorated CNTs were constructed with the regularly patterned microfluidic channels. Benefiting from the unique catalytic 3D nanoarchitectures and direct growth on electrodes, the as-fabricated fuel cells demonstrated maximum power densities along with the excellent durability, which significantly outperformed the fuel cell efficiencies of reported catalysts till date. The potential solutions for resolving the limitations of current environmentally benign fuel cells and extending their potential aspects on real-time applications will be addressed.

The large part of electrical energy is generated from fossil fuels, and the carbon dioxide produced in the process causes global environmental problems. One of the solutions to decarbonization is the use of storage batteries to promote renewable energy and improve its quality. The most widely used storage battery is the lithium-ion battery, but further performance improvements are needed to achieve the above goals. Against this background, there is a growing momentum to scientifically understand the interface and control its function.
The interface in a battery system typically has a third phase, called the solid electrolyte interphase (SEI), which is different from the two phases that form. Typical polymer electrolytes cannot be combined with 4V class cathode materials due to their low oxidation resistance. By controlling the electron transfer from the polymer electrolyte to the active material, by interposing a thin film of insulating ceramics such as Al₂O₃, the oxidation reaction can be suppressed.
Dissolution-deposition type electrodes, such as lithium and zinc metal, are not highly reversible, unlike insertion type electrodes. The formation of an inorganic SEI film such as LiF is known to be effective in improving reversibility. It suppresses side reactions between the electrode and the electrolyte, resulting in a uniform ionic current.
As mentioned above, the development of SEI is important for the realization of new storage batteries. Some examples of interface formation using spontaneous and artificial SEIs will be presented from the materials point of view.

In today’s global society, disease outbreaks can spread rapidly and easily across borders and continents, having a catastrophic impact on health and the global economy. Until May 2022, over 513 million people worldwide have been confirmed to be infected and more than 6.2 million have died due to SARS-CoV-2. There are treatments but no cures for most viruses.
Nevertheless, we can limit the spread of viruses by introducing antiviral coatings on public area surfaces and personal protective equipment (e.g., face masks). This work aims to fabricate a polymer-based coating with water-based polyurethane (PU) dispersion resin as a binder that can show antiviral activity against the Feline corona virus (FCov). The chosen polymer to function as an antiviral agent in this study is PEG, because it contains “green” chemistry benefits such as nontoxic, inexpensive, readily recyclable, safe, natural, nonflammable, biocompatible, and biodegradable. The PEG/PU coating systems of different weight percentages were coated on the glass substrates and cured at room temperature for 24 hours before the antiviral activity was analyzed. The coating system that contains 20wt% of PEG exhibits the highest anti-viral activities against FCov when compared with other weight percentages with a 3 log₁₀-unit reduction.

Due to the need of high performing, economic viable and safe rechargeable batteries, metal anode-basedsolid state batteriesare attaining huge attention in the present time.The main component of solid state batteries is the solid-state electrolyte for example, lithium lanthanum zirconium oxide LLZO which is a harsh ceramic in nature and results in highinterfecialresistance when it comes in contact with cathode or anode. Further, shortcircuiting failure of such batteries,caused by dendrite propagation through grain boundaries in solid-state electrolytes during cycling, is a major hitchtowards the commercialization. In this regard, mechanically stable ion conducting electrolyte interlayer between two electrodesis essential for suppressing the dendritic growth upon cycling. In this context, our group is consistently putting best effort to realize a solid or quasi-solid state battery. Fabrication of nanostructured based polymeric composite solid electrolyte membrane and direct deposition of solid electrolyte over the electrode surfaces have been tried to realize a safer and high performing solid-state batteries. In this talk, various strategies for development of solidelectrolyte interlayering between the cathode and anode having excellent mechanical and thermal propertieswill be discussed.

Oxygen concentration monitoring is necessary at two locations in a fighter aircraft; (i)The continuous monitoring of Oxygen concentration in the breathing gas supplied to the pilot, by an onboard Oxygen generating system. (ii)The continuous monitoring of Oxygen concentration in the Nitrogen enriched air supplied to the ullage-space of fuel tank, by an onboard inert gas generating system. Oxygen sensors based on Oxygen ion conducting solid state electrolyte, Yttria Stabilized Zirconia (YSZ), are preferred for aircraft applications. The characteristics of YSZ based Oxygen sensors developed in potentiometric and amperometric configurations for aircraft applications will be discussed.

Carbon nanotubes, functionalized with hydrides were found to have good hydrogen storing properties. Among the hydrides nanostructured metal hydrides are found to have better storage capacity. In particular for MgH₂, it is shown computationally that the hydrogen storage properties of nanostructured MgH₂ are significantly enhanced by proper engineering of the nanostructure. Nanophase MgH₂ exhibits good hydrogenation and reduced desorption temperature. The light free standing metal hydride, MgH₂, with selected nanophase, computationally shows high hydrogen storage capacity which with suitable substrate is bound to reduce to the useful range of 6.4 to 8.8 wt.%. Design and fabrication of Carbon 2D material, graphene, functionalized with nanophase MgH₂ is discussed.

Capacitors and batteries are two classes of popular electrical energy storage devices. One can charge a capacitor at very fast rate while a battery cannot charged at this fast a rate. But batteries can hold large amount of energy (KWh) whereas capacitors hold very little energy. In the present era, automobiles are operated with chargeable batteries. Every manufacturer wants to recover electrical energy while braking. The process is known as regenerative braking. During this process, lot of energy is generated in short span of time (few seconds). Thus to store this regenerated energy one needs a device that can hold large amount of energy and at the same time charge at a faster rate. Similarly, some of the electrical loads require enormous power to start functioning. Hence they need storage devices that can charge and discharge at a faster rate and at the same time store large quantum of energy. Supercapacitors are devices that satisfy these conditions.
There are three classes of supercapacitors: Electric double layer capacitors (EDLC), pseudocapacitors and hybrid capacitors. He double layer between an electrode and an electrolyte is the principle of operation of EDLCs. Carbonaceous materials like carbon dots, graphene, nanorods etc are the ones that are employed in the fabrication of EDLCs. Pseudocapacitors work on the basis of redox reactions at the electrode. They are mostly built around transition metal oxides, sulphides and conducting polymers. A third sclass uses both the principles and employs a mixture of oxides and carbon to get the benefits of both EDLC and pseudocapacitors and are known as hybrid supercapacitors.
When we employ the same material as the electrode for both the electrodes, it is known as a symmetric supercapacitors while the one that employs different materials as the cathode and anode is known as an asymmetric device.
The major components of a supercapacitor device are: the electrode, a current collector and the separator cum charge reservoir. Graphite sheet, porous metal sheets etc are employed as the current collector. The anode and cathode are separated by a thin layer known as the separator that prevents internal discharge. Usually this separator is soaked in an electrode for an extended period of time and acts as both the separator and the source of charges. The operating voltage depends on the type of electrolyte employed. The aquous electrolyte can go upto 1.2 V, while polymeric electrolytes permit operation upto 2.4 V. A third type known as room temperature ionic conductor (RTIC) can operate at over 4 V. This lecture will deal with these aspects and highlight the use of transition metal sulphides and ferrites as supercapacitor electrode materials.

Global warming due to the widespread industrial activities is a huge threat to the environment. Ever increasing industrial activities demand surplus of electricity. There is a dire need to generate electricity by clean, environment friendly methods without using non-renewable resources. Energy generation through thermoelectrics (TE) could be the ideal solution which can address both these issues.
The production of hydrogen from water by using combined activity of a catalyst and solar energy for environment friendly power generation might make us independent of our precious fossil reserves. An optimal material for hydrogen production would combine an ability to dissociate the water molecules, having a band gap that absorbs light in the visible range and to remain stable when in contact with water. Removal of carcinogenic dye molecules from the industrial waste water is also one of the important environmental issues. Current techniques such as adsorption, coagulation, sedimentation and filtration etc., are the non-destructive method of dye degradation. Photocatalytic dye degradation is one of the destructive method of waste water treatment released from industry.
Oxide materials have several advantages such as long term stability, low-cost, abundance, non-toxicity etc over other materials used for energy related applications. The presentation is about oxide based thermoelectric materials for waste heat recovery at different temperature ranges.ZnO and LaCoO3 are suitably doped to produce n and p type conductivity. Significantly high figure of merit was achieved in these materials through grain boundary and band structure engineering. The strategy of bringing the operating temperature (temperature of optimum performance) to the required level is done by making the composites of these oxides with suitable materials. Further, the challenges involved in the fabrication of thermoelectric modules using ceramic oxides will also be discussed.
Under Photocatalytic materials, Fe based complex oxides such as perovskites and spinels were found to be photocatalytically active under visible light due to the existence of Fe ions in the lattice with the tetrahedrally or octahedrally coordinated ligands, narrow bandgap energy and nontoxicity. Since their valence band edge is more positive than the oxidation potential of H2O, photooxidation reaction will occur easily. Their photo-reduction property can be further improved through suitable doping. A photocatalytic material needs to exhibit both properties of having suitable bandedges and bandgap. This can be achieved by dopingthe complex oxides in their cationic sites.

In the last three decades, graphene and metal organic frameworks (MOFs) have attracted considerable interest from material scientists. Especially in energy and environmental applications graphene-MOF hybrids have exhibited outstanding performance. However, till date synthesis of chemically derived graphene (CDG) from graphite as the starting material requires harsh chemicals for both oxidation and reduction whereas the organic linker in MOFs is usually chemically derived. In this manuscript we report a green and sustainable technique for concurrent reduction and subsequent growth of MOFs on reduced graphene oxide (rGO) by using citric acid as the inexpensive, bio-based, bio-degradable and sustainable chemical. Our work shows that citric acid not only effectively reduces graphene oxide to rGO, but also results in the formation of nano-sized, citrate-based MOFs anchored on rGO substrate to give unique meso-porous, CitMOF@rGO nano-hybrids. Preliminary results on the utility of Mn-CitMOF@rGO and Co-CitMOF@rGO in lithium ion batteries will also be reported.

Sodium-ion batteries (SIBs) can be harnessed as pragmatic alternative to the Li-ion battery technology having close operational similarity along with natural resource abundance. In case of sodium-ion batteries, apart from classical cationic redox-based cathodes, various cathodes have been unveiled based on anionic (oxygen) redox activity. This presentation will showcase two such case studies of novel cathode composition for SIBs exploiting anionic redox activity.
(1) P2-type manganese-rich layered oxides offers high capacity along with fast rate kinetics. To improve their electrochemical properties, reduce voltage decay upon cycling and to mitigate irreversible phase transitions, cation doping or hybrid composite integrations can be explored. We have tested a novel Mn-rich layer-spinel composite, Na_0.7(Li_1/18Mn_11/18Ni_3/18Fe_2/18x_1/18)O₂– xNa₂MoO₄, leading to a synergistic effect of layered P2 and spinel phases. This layer/spinel biphasic composite was stabilised through Mo doping and its electrochemical activity was studied at different voltage windows. Upon cycling between 1.5–4.5 V, this Mo-based composite exhibited a high specific capacity of 183 mAh.g^-1 involving both cationic and anionic (O2-/O2n-) redox activity. The structural evolution during (dis)charge was studied by ex-situ X-ray diffraction and cyclic voltammetry. It is observed that mitigating P2-P2´´ phase transition at higher voltage is crucial to improve the electrochemical performance, cycling stability and reduce the voltage hysteresis. The structural and electrochemical properties of this new composite cathode will be described.
(2) The second part will focus on anionic redox activity of Na-based mixed-metal oxide cathode [Na_0.7Mn_0.6Ni_0.3Co_0.1O2]. Combining cationic and anionic redox activity, it exhibited a reversible capacity of 120 mAh/g with anionic redox activity centered around 4.3 V. The underlying redox mechanism has been investigated using in-situ XRD and Raman spectroscopy showing peroxo bond formation. The structural and electrochemical properties of this new cathode composition will be explained.

Rechargeable solid-state batteries based on the fluoride shuttle are potential candidates to overcome the current generation lithium batteries due to their high energy density (5000 WhL^-1), fast charging and discharging rates to meet the increasing demand for electric vehicles with high performance and safety. However, the fluoride ion shuttle batteries suffer from the low ionic conductivity of the solid electrolytes forcing them to operate at temperatures around 150 °C. To develop a room temperature operatable fluoride shuttle battery, a solid electrolyte with high conductivity at ambient temperature is a prerequisite. Moreover, transport parameter such as mobility and diffusion coefficient which affects the performance of the battery during operation is not studied in detail for the fluoride ion conducting solid electrolytes. Most of the fluoride ion conducting solid electrolytes e.glead-based fluorides (e.g., PbF₂ or PbSnF₄), alkaline-earth fluorides (fluorite structure), and rare-earth fluorides (tysonite structure) are suitable electrolyte candidates for the development of fluoride ion shuttle batteries. In the present work, we have prepared various fluoride ion conducting solid electrolytes by mechanical milling process and studied the fluoride ion dynamics using 19F NMR spectroscopy and ac impedance measurements.

The effect of a lithium salt and inert nano fillers on the general polymer dynamics of poly(ethylene oxide) (PEO) and how these dynamical alterations affect the ionic conductivityand structural relaxations, α, β, γ-relaxations in (PEO)₄:LiClO₄ and (PEO)₄:LiClO₄ with nano fillers, have been investigated. The current study was based on differential scanning calorimetry (DSC) and dielectric relaxation studies. The DSC studies indicated an increased glass transition temperature of (PEO)₄:LiClO₄ as compared to that of PEO, however the glass transition temperature decreased for (PEO)4:LiClO4 with nano fillers. The polymer-salt complex exhibited ionic conductivity of σd.c. = 3.2 × 10^-7 S.cm^-1 at 298 K, due to the presenceof mobile Li+ ions. However, the presence of 4 wt% Al₂O₃ nano fillers enhanced the ionic conductivity by almost two orders of magnitude. Impedance data have been scaled and analysed under conductivity and modulus formalisms for all the systems. For PEO, the analysisof the scaled formalisms indicates that both the conductivity and the structural relaxation mechanisms are temperature-independent above the melting point of PEO. However, below the melting point, the nucleation and growth of spherulites and also the formation of ‘interphase’ regions in PEO result in a hindered long range D.C. conductivity, which, in turn, leads to a decoupling of the D.C. conductivity and the structural relaxation. However, for (PEO)₄:LiClO₄, by comparing the conductivity relaxation data with the calorimetric glass transition and analysis of scaled formalisms, a direct coupling between Li⁺ ion motions and polymer segmental dynamics is observed for the polymer electrolyte.

An intense degree of pollution caused by various substances has initiated alterations in our climate, exerting a substantial impact on our planet, including our biological organisms. Consequently, scientists are seeking sustainable and ecological materials for the purpose of manufacturing and industrial applications. A solid-state rechargeable battery is a type of electrochemical cell that is capable of both storing and generating electric energy. A fast-ion-conducting solid electrolyte is an essential element that serves as a barrier between the positive and negative electrodes of a cell. The study provides a comprehensive analysis of the electrical conductivity exhibited by solid electrolytes that conduct sodium ions. Sodium compounds are widely and inexpensively accessible materials that are non-toxic and environmentally friendly. Furthermore, sodium-ion batteries have similarities to lithium-ion batteries in terms of cell design and energy density, but they possess superior sustainability and ecological characteristics. We also discussed the electrical transport characteristics of the solid polymer electrolyte poly(ethylene oxide)x-disodium terephthalate. Disodium terephthalate is an organic salt with a molecular structure that includes two sodium ions for transportation. The mole ratio of composition x was adjusted from infinity to 8 in order to maximize the electrical conductivity.

In the era of global warming, batteries came out with the prodigious task of refurbishing industries and the transport sector, thereby reducing their reliance on fossil fuels for energy. For several decades, the bare bones of battery technology have remained little changed, allowing room only for incremental optimization. Recent breakthroughs on the solid electrolyte and electrode materials front are set to upend the incremental trend in the battery arena. If all goes well for solid-state electrolytes in terms of lifetime, high C rate, and cost, soon EVs will ply 1200 km non-stop on a single charge, and it will open up new areas of transport such as aviation, providedcharge-limiting graphite anode is replaced by lithium metal.
In this talk, I will discuss a few novel electrode and electrolyte materials from our laboratory. Solid polymer electrolytes (SPEs) have attracted great attention due to their flexibility and improved safetyfeatures1 . However,thepractical implementation of SPEs faces challenges such as low ionic conductivity at room temperature (RT), and high interfacial resistance between electrode/electrolyte resulting in poor cycle performance² . We report a quasi-gel-based polymer electrolyte (QGPE) comprising a blend of polymers and small molecules with desired mechanical strength, ionic conductivity, and interfacial stability through a simple solution casting technique. The QGPE with an optimized polymer weight ratio features a tailored surface, providing a buffer to reduce interfacial resistance and ensure homogeneous Li flux between the electrode and electrolyte. The optimized QGPE exhibits notable characteristics, including highionic conductivity (1.2 mS cm^-1 at RT), a Li⁺ transference number of ~ 0.5, and a broad electrochemical window (4.8 V vs Li/Li⁺ ).A lithium symmetric cell utilizing QGPE achieves a highly reversible lithium plating/stripping of lithium over 1300 h at a current density of 0.1 mA cm^-2 with minimaloverpotential. We have demonstrated the suitability of QGPE in solid-state LiFePO4/Li (148 mAh g^-1 over 200 cycles) and LiFePO4/Graphite (90 mAh g^-1 ) pouch cells.

Natural gums are typically composed of polysaccharides and they are obtained from various sources of plants, seaweeds, microorganisms, and trees. Their non-toxic nature allows them to be used in the food, textile, pharmaceutical, and paper industry. They have a lot of hydroxyl and other polar functional groups, which aid in the formation of polymer-salt complexes in the form of solid membranes. Here we investigate the electrical properties of guar gum and tragacanth gum for use in batteries and fuel cells. Tragacanth gum is an exudate of the shrub Astragalus gummier. It is a hydrophilic and anionic polysaccharide with a highly branching structure. Guar gum is a neutral polysaccharide produced from the seeds of guar plant. It has been tried as a binder material and electrolyte for battery applications. Both tragacanth and guar gum have shown an excellent film forming ability. Polymer-salt complexes of gums with ammonium, lithium, and potassium salts were developed for proton, lithium, and zinc batteries and their properties and uses will be covered.

Lithium-ion batteries have revolutionized the green energy landscape, powering electric vehicles and renewable energy storage systems. However, the environmental and social concerns associated with lithium mining have cast a shadow over this otherwise remarkable technology. In response, Aatral ESP, a groundbreaking startup from Chennai, has emerged with an innovative solution – sodium-ion batteries. By addressing the drawbacks of lithium-ion batteries, Aatral ESP is lighting the path to acleaner and more sustainable energy revolution.
Lithium mining, particularly in nations like the Democratic Republic of Congo, has brought significant challenges to light. Artisanal mining practices lacking regulation and safety standards have endangered miners, exposing them to accidents and health hazards. Moreover, the extraction process consumes vast amounts of water and land, leading to environmental degradation and resource depletion. As the world seeks greener energy solutions, it is imperative to address these issues and seek alternatives that prioritize both theenvironment and affected communities.
The advantages of Aatral ESP's sodium-ion batteries over their lithium-ion counterparts are numerous. Sodium's abundance ensures a more sustainable and indigenous production process, reducing concerns about resource depletion and geopolitical dependencies. Additionally, the manufacturing costs of sodium-ion batteries are projected to decrease by over 30% due to the higher availability of raw materials. The safety aspect is another key advantage. They are fire safe and as sodium-ion batteries can be drained completely, eliminating the risk of explosions, and making transportation safer. Furthermore, these batteries exhibit exceptional performance and versatility, with operating temperatures ranging from -40 to +60 degrees Celsius, making them ideal for diverse climatic conditions.
As the world grapples with the dark side of lithium mining, Aatral ESP's sodium-ion batteries offer a ray of hope. By mitigating the environmental and social challenges associated with lithium extraction, Aatral ESP is paving the way for a greener and more sustainable energy revolution. With their abundant raw materials, reduced manufacturing costs, and superior safety and performance, Aatral ESP's sodium-ion batteries stand poised to reshape the energy storage industry. Let us embrace this innovative startup and embark on a journey towards a brighter, cleaner, and responsible energy future.

It is very important to efficiently and environmentally friendly utilize fossil fuels. Proton conducting solid oxide fuel cell reactors have been developed for co-generation of electrical energy and value-added chemicals of alkene (such as ethylene) from alkane (such as ethane) without CO₂ greenhouse gas emissions: (1) alkane is partially dehydrogenated at anode with simultaneously production of protons and electrons, which respectively are transported through the electrolyte and the external circuit. Unlike conventional industrial processes, alkane dehydrogenation in the fuel cell is not equilibrium limited, and is not in contact with oxidant, and so alkane can be converted to alkene with high selectivity and without producing CO₂; (2) at the cathode protons react with oxygen from air and consume electrons from the external circuit to produce water, and the chemical energy thereby is used to generate electrical power. Unlike conventional hydrocarbon fuel cells with oxygen ion conducting electrolyte, there are no significant greenhouse gas (CO₂) or poisonous gas (CO) emissions. As protons are rapidly conducted away from the catalyst through the electrolyte, there is no buildup of hydrogen at the anode, and so there is no reverse reaction of alkene. Thus the cell not only promotes ethane conversion but also provides for separation of alkene and co-production of energy, in contrast to the convnetionalprocess for alkene production by thermal alkane dehydrogenation which need a large amounts of energy consumption.

This report will focus on the microstructure-property relationships of functional composite interfaces in high-energy-density metallic lithium batteries. Aiming at key scientific issues including the formation mechanism and evolution rules of interface functional composite structures, we revealed the functional composite interface mechanism in metallic lithium secondary batteries from the nanoscale, and demonstrated the unique research on microscopic analysis and regulation of sensitive battery materials. 1. We established the universal self-assembled monolayers technology toward generating a stable lithium anode interface. We have first demonstrated interphase catalysis effect originating from long-range ordering organic molecules and thus addressed the typical challenge of uncontrollable electrolyte degradation. 2. We have developed the nanoscaled methodology for visualizing the interfaces between sensitive polymer and metallic lithium. Since the solid polymer electrolyte was published more than 50 years, for the first time, we testified the long-established theoretical prediction of the solid polymer electrolytes’ interface structure through experiments. 3. We proposed the interface stabilization mechanism of the functional composite structure and obtained a high specific energy metal lithium battery with one of the best cycle stability.

Na-ion batteries (NIB) are a promising charge-storage device and considered as a potential alternative to the existing state-of-the-art Li-ion batteries (LIB). In contrast to the Liinsertion into graphite, Na-insertion into graphite and subsequent formation of the binary graphite intercalation compound (LiC6) are not possible and are thermodynamically unstable in the presence of ester solvents. In the present work, we report the successful and efficient recovery of both the anode (graphite) and polypropylene (PP) separator from the dead LIBs. Further, we have used ethers as a solvent for the reversible intercalation of the Na-ions into the graphitic anode via the solvent-co-intercalation process. This solvent-co-intercalation process enables the formation of ternary graphite intercalation compoundwith high Na-ion reversibility. The NIBsare fabricated with the carbon-coated–Na₃V₃(PO4)3 as cathode and recovered graphite as an anode in the presence of TEGDME solution with polypropylene (PP) as a separator under the balanced mass loading conditions. The necessary physical and electrochemical studies are performed individually for all the components. The full-cell assembly, C/PP/Na₃V₂(PO₄)₃, rendered a maximum energy density of 78 Wh kg_-1 (based on total active mass loading) at ambient temperature conditions. The detailedresults and related information will be discussed during the presentation.

Lithium metal possesses high theoretical specific capacity (3860 mAh g^-1) and a low electrochemical potential, and has become an ideal negative electrode material for future lithium metal batteries. Unfortunately, due to uneven lithium deposition, the lithium metal cathode faces a serious Li dendrite problem, which seriously inhibits its practical application. By optimizing the electron density of Li metal cathode surface, the local coordination environment of Li⁺ can be adjusted, thus inhibiting the growth of Li dendrites to achieve high-performance Li metal batteries. As a new class of two-dimensional organic porous materials, COF provides favorable conditions for electronic regulation. Single atom metal engineering is an effective strategy to promote charge transfer to host and adjust electron density. Importantly, the electron-rich states around the metal atoms can optimize the local coordination environment of Li⁺, promote the rapid migration of Li⁺, and achieve uniform Li deposition behavior. Therefore, we prepared sp2c-COF with a single atomic metal (Co) site and used it as an artificial SEI on the lithium metal negative surface to improve the electrochemical performance of lithium metal batteries. In addition, solid-state lithium metal batteries have attracted wide attention because of their unique advantages of high safety and high energy density. However, the scientific problem of the complex interface has always been a difficulty in the research of high stability solid-state batteries. Therefore, a SEI/CEI dual interface cooperative protection strategy for high nickel solid state lithium batteries is proposed in this study. A multifunctional gel electrolyte was synthesized by in-situ polymerization and electrochemical test was carried out. During the charging and discharge process, CEI protective layer with strong oxidation resistance is spontaneously constructed on the positive side of high nickel electrode under chemical induction, and SEI protective layer with good mechanical properties and high ionic conductivity is constructed on the negative side of lithium electrode.

The solid-state lithium batteries have attracted a great deal of attention, due to their potential in enhancement of energy density as well as improvement of safety. Under such context, LLZO-based garnets become one of the most promising electrolytes. However, the surfaces of garnets are usually coated by Li₂CO₃ that is formed by attack of H₂O and CO₂ in air. Such insulating and lithium-phobic coating layers cause not only the sluggish ion transport across the interface but also the contact problems with the lithium anode. In this presentation, we will address our recent progress on manipulation of such Li₂CO₃ layers, including how to hinder its formation, how to remove it by chemical process, and how to turn it constructive by conversion reactions for good fitting with the Li anodes and the polymers. The long-cycle solid state lithium batteries with the LLZO-ceramic and LLZO/polymer composite-based cells will be given to demonstrate the effectiveness of strategy presented here. The underlying mechanism will also be addressed.

The anticipation of increased per capita energy demand across the world in future stimulates the need for safer and more energy-dense storage solutions. However, the presently available battery technology shows safety concerns during faster charging and discharging and long-range usage. The safety issues mainly arise from the combustible liquid electrolyte present inside. In all solid-state batteries (SSB), a solid electrolyte is present instead of the liquid electrolyte and thus, provides a better alternative for safer operation. In addition, the SSB provides more energy and power density thus reducing the volume requirement too. SSBs are promising candidates for next-generation mobility and transportation sectors but come with a penalty of various mechanical stress-related degradation issues. Understanding their electrochemical performance along with their mechanical behaviour has become essential to effectively harness their potential. A coupled physics-based model of solid-state batteries considering the interplay of electrochemical and mechanical effects is developed for deeper understanding. The battery model considers a layered architecture of cathode, solid electrolyte and anode. The coupling coefficient defined in the model represents the degree of closeness of mechanical stress effects on electrochemical performance. An analysis of the effect of deviatoric stress and pressure effect on the electrochemical potential difference and surface overpotential dropsfor different materials will be presented. The effect of thickness variation of solid electrolytes inside the layered architecture and the effect of external stiffness on interior electrochemical behaviour will also be presented. This model may be used as an effective way for studying SSBs with respect to different initial states, materials combinations and structural parameters.

NASICON-type Na⁺ conductors show a great potential to realize high performance and safety for solid-state batteries (SSBs) owing to their superior ionic conductivity, high chemical stability and low cost. However, the interfacial incompatibility and sodium dendrite hazards still hinder its applications. Herein, we demonstrate a gradient sodiophilic and electron-blocking multifunctional interphase consisting of sodium-tin (Na-Sn) alloy and sodium fluoride (NaF) to modify the surface of the Na_3.3Mg_0.15Zr_1.85Si₂PO₁₂ (MNZSP)ceramic electrolyte through in-suit conversion reaction between Na and SnF₂coating layer. The reaction product, Na-Sn alloy near the side of the sodium electrode, has high sodium-ion diffusion coefficient,which enhances the anodic Na+ transportation kinetic while the obtained NaF near the side of theceramic electrolyte, is an electron insulator,hindering the interfacial electron turning ability,and thus resulted in the uniform and dendrite-free deposition of Na⁺ during the cycling. Profiting fromthe synergistic effect of thegradient interphase, the critical current density (CCD) of the assembled Na symmetric cell is significantly increased to 1.7 mA cm^-2 and the cycling stabilityof that is as high as1200 h at 0.5 mA cm^-2 . Moreover, quasi-solid-state sodium batteries with both Na₃V₂(PO₄)₃ and NaNi_1/3Fe_1/3Mn_1/3O₂ cathode display outstanding electrochemical performance.

The development of new materials that can solve the challenging problems in the areas of clean energy production, conversion and storage is of paramount importance. Despite of huge research in the field of supercapacitors, they still lag behind batteries in terms of energy storage capacity. It is required to further enhance the capacitance of supercapacitors to increase their energy storage capacity. One of the major factor on which the capacitance of the supercapacitor depends upon is the electrode material. Many materials have been explored for the fabrication of supercapacitor electrodes but still the capacitance obtained is not high enough. In the present study, theoretical modeling has been done to investigate electrodes for supercapacitor applications.DFT calculations are performed for pure and doped graphene using boron, sulphur and phosphorus as dopants to improve the quantum capacitance of electrodes fabricated using graphene. The effect of increasing doping concentration on quantum capacitance is also investigated. The density of states and quantum capacitance of pure and doped niobium nitrides are also investigated using density functional theory calculations. These calculations are also performed for cobalt doped niobium nitrides. The impact of spin and number of layerson quantum capacitance is also studied for Nb₂N and Nb₄N₃ electrodes. The temperature dependence of quantum capacitance is also investigated for all electrode materials studied.

Aqueous batteries are one of the key directions for developing low-cost, high-energy-density, and safe energy storage systems. Traditional zinc-based batteries employing intercalation-type positive electrode materials exhibit low zinc storage capacity and slow kinetic processes, which do not match the high-capacity characteristics of zinc negative electrodes, thus failing to fully leverage the true advantages of aqueous batteries. Based on the electrode potentials of halogen reactions, they can serve as charge carriers to construct batteries, such as chloride-ion batteries and fluoride-ion batteries, and can also act as electrode-active materials for energy storage. Due to the solubility of halogens, halogen electrode reactions typically exhibit fast kinetics and have been widely used in various types of batteries, such as Zn-I₂, Li-I₂, Zn-Br₂, etc.By utilizing the multivalent characteristics of halogens, we designed the solvation structure of the electrolyte to achieve a four-electron consecutive conversion process of I_-/I₂/I₊. The high-valence state conversion (I₂/I₊ couple) has a higher reaction potential compared to the traditional two-electron process (I_-/I₂ couple), leading to a doubling of the capacity of zinc-iodine batteries and a significant increase in the energy density of the battery.Addressing the challenges of complexity and cost in zinc-bromine flow battery systems, we developed a class of electrolyte additives that allow the real-time conversion of Br₂ generated during the electrochemical process into a solid phase. This eliminates the need for ion-selective membranes and complex pump systems in flow batteries, enabling the Zn-Br system to operate in a static environment. This static zinc-bromine battery maintains the high cycling stability and intrinsic safety features of flow batteries.This talkwill provide a detailed account of our thoughts and progress in halogen based aqueous batteries.

Faced with the higher requirements of building energy conservation for comprehensive regulation of solar light and heat, it is necessary to meet the dual functions of summer heat insulation/winter heat preservation; Focusing on the research of inorganic intelligent light and heat regulation materials and devices, the speed of active intelligent light and heat comprehensive regulation is slow, poor stability and other problems, a new method of proton relay transmission is proposed to achieve ultra-fast transfer of proton in the solid electrolyte, greatly improving the discoloration speed and stability of the device. Aiming at the problem of adaptive photothermal comprehensive regulation, a new structure of multi-layer composite film system is proposed to achieve dual improvement of visible light and solar energy regulation rate. Vanadium dioxide (VO₂) is a representative material for typical adaptive photothermal regulation. Optical performance tuning and stability are basic scientific issues and problems that restrict its application. Elucidate the degradation mechanism of VO₂ films and establish a long-life film preparation plan; develop a high-performance VO₂ self-rolling multi-level control structure; provide theoretical and technical support for the application of photothermal materials.

Enhancing energy density stands as a paramount research goal in the field of lithium-ion batteries, and the development of high-capacity anode and cathode materials represents a crucial avenue toward achieving this goal. However, high-capacity electrode materials typically coincide with a notable deterioration in structural stability during the electrochemical process, posing challenges for their practical applications. Nanoscale structural design emerges as a predominant approach to address these challenges. Through integrating phases with distinct properties in a specific nanoscale form, the unique characteristics of different phases are leveraged to balance the diverse design criteria, such as capacity and stability. Therefore, exploring nanocomposite structures and nanoscale short-ordering patterns within materials, as well as their evolution during electrochemical processes, proves critically important for designing high-capacity cathode materials with robust structural stability. By employing lithium cobalt oxide and lithium-rich oxide cathode materials as examples, this report presents the strategies for developing high-capacity oxide cathode materials via a comprehensive design of nanostructures at different levels, including bulk phases, grain boundaries, and surfaces. Furthermore, their application in high-energy-density solid-state batteries is briefly discussed.

Sodium-ion batteries (SIBs) have attracted wide attention in recent years due to their abundant sodium resources and low cost. Polyanionic compounds are the promising cathode materials for SIBs owing to their stable framework structures and high operating voltage. This talk focuses on the structural regulation of polyanionic materials, including material design and preparation, regulation of ion transport, and electrochemical properties. The talk contains: (1) the structure analyses of polyanionic materials, the intrinsic reasons affecting ion diffusion behaviour, and the structural design and surface/interface modification of a series of polyanionic materials; (2) the application of polyanionic compounds in pouch cells, and the electrochemical properties and safety tests of the pouch cells.

Semiconductor based photochemical and photoelectrochemical water splitting is an ultimate source of hydrogen generation as renewable green energy for tackling the ongoing fuel crisis. g-C3N4 is an ideal candidate for overall water splitting as a result of the excellent alignment of its band edges with water redox potentials. However, a single catalyst with a limited number of active sites does not exhibit significant photo/electrocatalytic activity for hydrogen production. Therefore, we have developed the semiconductor heterostructures of g-C₃N₄ with CuFe₂O₄, Cu₂O, CdSe, CdS and MoS₂ NPs and QDs as the highly efficient nanocatalysts for enhanced hydrogen evolution reactions. The monophasic heterostructures have been designed in different weight ratios with fairly uniform distribution of nearly spherical particles and high specific surface area which creates an interfacial charge transfer between two semiconductors. As prepared heterostructures showed significant hydrogen evolution which is evident by observing high apparent quantum yield, low onset potential, lower overpotential and high electrochemical active surface area that will be presented in detail.

As the petroleum resources are being depleted and concern on the environmental pollution increases, electric vehicles (EVs) and renewable energies like solar and wind are becoming highly desirable. It is a big challenge to develop electrical energy storage systems that can meet the rigorous requirements on the weight and volume in electric vehicles, and cycle life and efficiency for grid energy storage. Lithium-ion (Li-ion) batteries, representing the highest energy density battery chemistry, are believed to be one of the most promising systems for these applications. However, the capacities in the current cathode materials have reached their limits of lesser than 250 mAh/g. To further increase the energy density of Li-ion batteries, alternative high capacity cathode materials are being actively developed. Organosulfurcompounds such as dimethyl trisulfide (DMTS) containing sulfur-sulfur bonds are a class of potential high-capacity cathode materials for batteries. However, most of them are soluble in liquid electrolyte, which makes it difficult to keep them electrochemically reversible in rechargeable batteries. In 2016, our group reported the first study of DMTS as a cathode material in rechargeable lithium batteries. Afterwards, we reported several organosulfur cathode materials such as diphenyl polysulfides and dipyridyl trisulfide etc. By using a series of characterization techniques, we are able to reveal their redox mechanisms in rechargeable lithium batteries. In addition to being cathode materials, these organosulfur molecules can be used as functional materials as electrolyte additives, deep eutectic electrolyte, and key components in solid-electrolyte interphase in batteries. In this talk, I will introduce our approach to enable the electrochemical reversibility of these soluble materials and reveal their redox mechanisms. The intriguing redox mechanisms associated with organosulfur provide a 69 broad space to develop advanced cathode and batteries for the next-generation electrochemical energy storage devices.

The escalating global demand for energy, environmental concerns, and the diminishing reserves of fossil fuels have driven extensive research into the development of efficient electrochemical energy storage devices. These devices, which include rechargeable batteries (such as lithium and sodium batteries), supercapacitors, and fuel cells, are under investigation as potential energy sources for automotive applications, including electric vehicles (EVs) and hybrid electric vehicles (HEVs). However, to meet the stringent requirements for automotive use, further improvements in the electrochemical performance of these devices are necessary, with a particular focus on capacity, cyclability, energy density as well as safety.
The cathode materials play a pivotal role in influencing the performance of rechargeable batteries. Therefore, discussion on high-capacity cathode materials, both pristine and coated variants of NMC will be the main focus of this talk. These materials have been rigorously tested within rechargeable sodium batteries that were fabricated in our laboratory. The presentation will also cover various surface modification strategies employed to enhance the performance of these secondary batteries.

Lithium-ion batteries (LiBs), despite of their attractive properties, are associated with risks related to developed heat, gas emissions, explosions and fire. Such events are rare,and their consequences can be mitigated by the cathode nature, but if a LiB is overheated or overcharged it may result in immediate or delayed venting.
In this work, cylindrical 3.2 Ah LFP cells and prismatic 50Ah NMC cells have been abused by overcharging, in some cases by preheating, analyzing qualitatively and quantitatively the emissions. FT-IR coupled with electrical thermal measurements and electrochemical gas sensors was monitored with continuity.
To facilitate theventing, in some cases, the cell case was pre-perforated.The behavior of the two cell types was different, By the cut off voltage most of the volatile part of the electrolyte had been evaporated and the temperature reached about 140 °C for the LFP cell. HF and POF₃ were emitted at an earlier stage than in usual thermal abuse tests.

Zinc ion batteries (ZIBs) are emerging as a promising candidate for the next generation of energy storage solutions due to their unique combination of characteristics, which make them a viable alternative to traditional lithium-ion batteries (LIBs). These batteries leverage Zinc as the key component in their anode, offering several advantages over other materials. Firstly, Zinc is abundant and widely available, making it a cost-effective material for battery production. This abundance helps reduce the overall cost of manufacturing, addressing one of the key challenges associated with LIBs, which often rely on scarce resources. Secondly, using Zinc in the anode improves thermal stability, reducing the risk of overheating and potential safety hazards. ZIBs can achieve a high energy density and perform long cycles, making them suitable candidates for grid-scale energy storage. Also, Zinc is a non-toxic and recyclable material, contributing to a more sustainable approach to energy storage. In this regard, we have synthesized spinel zinc manganate (ZnMn₂O₄), and their performance was tested in aqueous and non-aqueous electrolytes. The comprehensive electrochemical investigations indicate that our materials are suitable to be employed as cathodes for ZIBs.

The growing need for sustainable energy sources has compelled researchers globally to intensify their efforts in advancing research and development within the field of renewable energy. Currently, the captivating and unique traits of metal oxide nanocomposites have garnered substantial attention from researchers, solidifying their status as a favoured research focus among diverse groups of researchers globally. Strontium titanate (STO) and Zinc Oxide (ZnO) are distinguished by their chemical stability, minimal toxicity, and cost-efficiency, making them an excellent choice for use in environmental remediation and the production of clean energy.Researchers have exerted substantial efforts toward altering the electronic and physicochemical makeup of STO and ZnO, with a specific emphasis on doping treatments or creating defect sites with specialized nanoarchitecture. Substituting Manganese (Mn) in STO and increasing the defect sites in ZnO show potential for encouraging the generation of oxygen vacancies (Vo) and inducing lattice distortion, while concurrently modifying the catalyst's band structure, specifically adjusting the position of the valence band maximum (VBM) and conduction band minimum (CBM).Skilfully manipulating the distribution of electrons results in the development of effective paths for charge transfer between Vo and nearby metal atoms, accelerating the movement of charge carriers and enhancing the division of photoexcited electrons and holes. Mn-STO lattice boosts the efficiency of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) by amplifying the electrochemical surface area and the number of active sites, thereby fostering interactions at the interface between the electrode and electrolyte. The successful development of 3D nanoflowers (NFs) featuring a distinct ZnO nanostructure, notable for its abundance of defect sites, serves as a photocatalyst to degrade Rhodamine B (RhB) and enhanced photocurrent response leads to improved separation of photogenerated charge carriers. This research plays a key role in tackling future environmental challenges by offering novel perspectives and meeting the rising demand for energy resources.

The development of non-lithium-based energy storage devices is a critical necessity because of the increasing energy demand and the uneven distribution of lithium sources. Potassium-ion battery (KIB) technology is considered a potential alternative to Li-ion Battery (LIB) technology because of their unique features like the high working voltage, the standard electrode potential of K+ /K (−2.93V versus standard hydrogen electrode)is close to Li+ /Li (−3.04V) in the aqueous system, the lower K + /K redox potential (−2.88V)as compared to Li+ /Li(−2.79V), the weaker Lewis acidity of K+ leading to a smaller radius of solvated ions in comparison with Li+ and high ionic conductivity that facilitate the diffusion of K+ in carbonate ester electrolytes. Besides, K is more abundant than Li, comprising ~2.09 % of the earth's crust by weight, which makes it cheaper than Lithium. KIBs can be manufactured using the existing lithium-ion battery (LIB) plants because of the similar reaction mechanism of K & Li. Nevertheless, KIB technology is in its infancy stage, and many challenges remain to be explored to commercialize KIBs. Graphite has been reported as a better choice of anode for K+ storage, but significant volume changes during the charge/discharge process due to the large size of K+ ruin long-term cycling performance. In addition, low volumetric and gravimetric energy density and the short cycle life of KIBs lead to the demand for high-voltage cathode materials. Designing suitable cathode/anode materials and stable electrolytes is the better strategy for enhancing the energy density of KIB and enduring their long-term high-voltage applications. In this context, this talk focuses on the advantages, limitations, and performance metrics of different classes of electrode materials for KIBs and the obstacles hindering the widespread application of KIBs.

Fullerenes are a collection of carbon molecules with potential applications in energy storage/conversion for their excellent properties, such as good conductivity, high stability and tunable functionality. While self-assembly of fullerene molecules into micro/nanostructures may promote their applications in different fields, we have succeeded in the controlled fabrication of fullerene micro/nanostructures with different morphology, dimension, size and crystallinity, expanding their applications as high performance electrocatalysts and next-generation rechargeable batteries.

Global electric vehicle (EV) sales trends project several million vehicles (>100 million) on road by 2030. Achieving this target depends on the broad deployment of lithium battery technologies that are safe, affordable and energy dense. Modern EV batteries are often designed with the aims of achieving – (i) reduced battery cell cost <$80/kWh, (ii) increased EV range >300 miles, and (iii) decreased charge times lesser than 15 min. Additionally, for establishing battery manufacturing competitiveness in a country as a strategic interest, it is of categorical importance to secure critical raw material supply chains and develop cost-effective and profitable battery manufacturing industries within the country. For manufacturing modern Li-batteries, a major part of the manufacturing cost goes towards one element in the cathode – cobalt (~30%). Cobalt prices in recent years, have constantly been rising resulting in an unsustainable trend. However, mainstream commercially available Li-battery cathode materials, such as layered NMCs and NCAs, contain significant amounts of cobalt in their composition. Cobalt has thus become a critical resource that has pushed battery companies into a desperate search for a viable cost-effective alternative. To address this cobalt conundrum, modern battery manufacturing R&D efforts should be directed towards eliminating the need for cobalt in traditional cathode architectures replacing it with cost effective elements resulting in a new class of cobalt-free cathodes. Here, we will discuss the R&D efforts and technical development into new cobalt-free cathode families termed as the NFA Li_xFe_yAl_zO₂ (x+y+z=1) and the NMA class, LixMnyAlzO2 (x+y+z=1). These co-free cathode familiesdemonstrate similar material propertiesand can be synthesized using prevalent commercial processes while delivering comparable performance (capacity >200mAh/g) compared to mainstream commercial cobalt-based cathodes. Thus, thesenew classes of cathodesare ideal for achieving seamless integration into existing battery manufacturing infrastructures without the need for a complete overhaul. Broadly these cathode chemistries are ideally suited for the development of advanced next-generation lithium-ion batteries that can usher in the modern EV revolution without the need for securing expensive cobalt and related material supply chains.