Next-generation Battery Technologies Research Articles

A Highly Effective Polysulfide-Trapping Approach for the Development of High Energy Density, Scalable Lithium-Sulfur Batteries

Abstract Lithium-sulfur (Li-S) batteries are identified as one of the most promising next-generation battery technologies owing to their high theoretical specific energy, sustainability, and affordability. However, the commercialization of Li-S batteries has been hindered by severe technical challenges, including the lithium polysulfide (PS) dissolution/shuttling effect, a major cause of fast capacity degradation over cycling. We demonstrated that nanolayer polymer coated high surface area porous carbons (NPCs) were coated directly on sulfur electrodes (NPC-S), which led to a high specific capacity of ~1,600 mAh/g approaching the theoretical specific capacity limit. The NPC-S based Li-S batteries maintained their large initial specific capacity gain compared with the Baseline-S based Li-S batteries (control) over extended cycles. Our experimental and computational results suggest that NPC coated on sulfur electrodes provides not only an effective and strong PS-trapping power but also an increased redox reaction kinetics during battery charge and discharge, rendering the realization of near-theoretical discharge specific capacity in the NPC-S based Li-S batteries. The findings presented in this study may inspire a new, simple, low-cost, and commercially scalable approach, without adding any appreciable dead weight or volume to the batteries, in the effort to tackle the technical challenges facing SOA Li-S batteries.

Beyond lithium-ion: emerging frontiers in next-generation battery technologies

The rapid advancement of technology and the growing need for energy storage solutions have led to unprecedented research in the field of metal-ion batteries. This perspective article provides a detailed exploration of the latest developments and future directions in energy storage, particularly focusing on the promising alternatives to traditional lithium-ion batteries. With solid-state batteries, lithium-sulfur systems and other metal-ion (sodium, potassium, magnesium and calcium) batteries together with innovative chemistries, it is important to investigate these alternatives as we approach a new era in battery technology. The article examines recent breakthroughs, identifies underlying challenges, and discusses the significant impact of these new frontiers on various applications–from portable electronics to electric vehicles and grid-scale energy storage. Against the backdrop of a shifting paradigm in energy storage, where the limitations of conventional lithium-ion batteries are being addressed by cutting-edge innovations, this exploration offers insights into the transformative potential of next-generation battery technologies. The article further aims to contribute to the ongoing scientific dialogue by focusing on the environmental and economic implications of these technologies.

Variation of electrochemical performance of Li2ZrCl6 halide solid electrolyte with Mn substitution for all-solid-state batteries

All-solid-state batteries (ASSLBs) have gained attention as a next-generation battery technology. Halide solid electrolytes may be a candidate material for next-generation batteries due to their high stability in combination with cathode-active materials and good deformability. However, the halide solid electrolyte exhibits low ionic conductivity compared to other solid electrolytes, such as oxide and sulfide solid electrolytes. In this study, in order to improve the ionic conductivity, a strategy is presented to increase the ionic conductivity by changing the Li + concentration and metal charge by doping Mn2+ in the trigonal Li2ZrCl6. Mn-doped Li2ZrCl6 is synthesized by high-energy ball-milling. Structural analysis is conducted by powder X-ray diffraction, 7Li-Nuclear magnetic resonance, Raman spectroscopy and X-ray photoelectron spectroscopy. Electrochemical performance is evaluated using electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charge-discharge measurement. Each value of ionic conductivity in the bare and optimized compositions is 0.4 mS cm−1 and 0.8 mS cm−1, respectively. The activation energy of Li2ZrCl6 and 5 mol% Mn doped Li2ZrCl6 is 0.342 and 0.326 eV. Galvanostatic charge-discharge is conducted to confirm cycling performance. The initial discharge capacity for Li2ZrCl6 and 5 mol% Mn-doped Li2ZrCl6 are 171.6 and 185.6 mAh g−1, respectively.

Defect engineering enables an advanced separator modification for high-performance lithium-sulfur batteries

High-energy–density lithium-sulfur batteries have been rated as a promising, yet challenging, next-generation battery technology. Typically, the serious shuttle of polysulfide intermediates and sluggish solid–solid reaction kinetics often result in irreversibly sulfur loss, low Coulombic efficiency, and limited lifespan. Herein, we propose a facile and efficient separator modification strategy using a rationally designed sulfiphilic and lithiophilic mediator, i.e. in-situ confinement growth of oxygen-deficient TiO2-x nanoparticles within nitrogen-doped mesoporous carbon matrix to modulate the sulfur electrochemistry. The nanoscale defective catalyst within open mesoporous host affords favorable adsorption of polysulfides and catalytic conversion ability. Moreover, the versatile composite improves the electrolyte wettability and Li+ transfer kinetics and alleviates self-discharge behavior. Resultantly, the Li-S batteries using modified separator achieves significantly improved cycling stability with a low capacity decay of only 0.067% per cycle after 500 cycles at 2C. The defect engineering together with separator modification strategies enable efficient and durable Li-S batteries.

DFT insights into the adsorption mechanisms of lithium polysulfides on Ni2P (0001) surface for lithium–sulfur batteries

Reliable and sustainable energy storage systems are crucial for a renewable energy future. The ultrahigh theoretical specific capacity and energy density of lithium–sulfur batteries (LSBs) make them one of the most promising next-generation battery technologies. However, their large-scale applications are seriously limited by rapid capacity fading and poor Coulombic efficiency owing to the shuttling of lithium polysulfides (LiPSs). Herein, we investigate nickel phosphide (Ni2P) as an effective host material to realize high-performance LSBs based on first-principles density functional theory (DFT) calculations. Our calculated adsorption energies of the LiPSs species reveal that the Ni2P(0001) surface possesses moderate to high adsorption strength and the adsorption process is facilitated via charge transfer from the LiPSs to the interacting Ni2P(0001) surface atoms. Due to the strong interactions between Ni2P(0001) and LiPSs (Li2Sx, x = 1, 2, 4, 6 and 8), we observe elongation of the intramolecular Li–S bonds in LiPSs upon their adsorption. The stronger adsorption of Li2S coupled with its spontaneous dissociation suggests a faster charging process could occur on the on Ni2P(0001) surface. These results demonstrate that Ni2P can provide effective anchoring sites for the soluble LiPSs, potentially having implications for the design of electrodes for practical LSBs.

Heterostructured WOx /W2 C Nanocatalyst for Li2 S Oxidation in Lithium-Sulfur Batteries with High-Areal-Capacity.

Lithium-sulfur (Li-S) batteries show extraordinary promise as a next-generation battery technology due to their high theoretical energy density and the cost efficiency of sulfur. However, the sluggish reaction kinetics, uncontrolled growth of lithium sulfide (Li2 S), and substantial Li2 S oxidation barrier cause low sulfur utilization and limited cycle life. Moreover, these drawbacks get exacerbated at high current densities and high sulfur loadings. Here, a heterostructured WOx /W2 C nanocatalyst synthesized via ultrafast Joule heating is reported, and the resulting heterointerfaces contribute to enhance electrocatalytic activity for Li2 S oxidation, as well as controlled Li2 S deposition. The densely distributed nanoparticles provide abundant binding sites for uniform deposition of Li2 S. The continuous heterointerfaces favor efficient adsorption and promote charge transfer, thereby reducing the activation barrier for the delithiation of Li2 S. These attributes enable Li-S cells to deliver high-rate performance and high areal capacity. This study provides insights into efficient catalyst design for Li2 S oxidation under practical cell conditions.

A compatibility study of protective coatings for temperature sensor integration into sodium-ion battery cells

Instrumented battery cells (i.e. those containing sensors) and smart cells (with integrated control and communication circuitry) are essential for the development of the next-generation battery technologies, such as Sodium-ion Batteries (SIBs). The mapping and monitoring of parameters, for example the quantification of temperature gradients, helps improve cell designs and optimise management systems. Integrated sensors must be protected against the harsh cell electrolytic environment. State-of-the-art coatings include the use of Parylene polymer (our reference case).We applied three new types of coatings (acrylic, polyurethane and epoxy based) to thermistor arrays mounted on flexible printed circuit board (PCBs). We systematically analyse the coatings: (i) PCB submersion within electrolyte vials (8 weeks); (ii) analysis of sample inserted into coin cell; (iii) analysis of sensor and cell performance data for 1Ah pouch SIBs. Sodium-based liquid electrolyte was selected, consisting of a 1 M solution of sodium hexafluorophosphate (NaPF6) dissolved in a mixture of ethylene carbonate and diethylene carbonate in a ratio of 3:7 (v/v%). Our novel experiments revealed that the epoxy based coated sensors offered reliable temperature measurements; superior performance observed compared to the Parylene sensors (erroneous results from one sample were reported, under 5 d submersed in electrolyte).Nuclear magnetic resonance (NMR) spectroscopy revealed in the case of most coatings tested, formation of additional species occurred during exposure to the different coatings applied to the PCBs. The epoxy-based coating demonstrated resilience to the electrolytic-environment, as well as minimal effect on cell performance (capacity degradation compared to unmodified-reference, within 2% for the coin cell, and within 3.4% for pouch cell). The unique methodology detailed in this work allows sensor coatings to be trialled in a realistic and repeatable cell environment. This study demonstrated for the first time that this epoxy-based coating enables scalable, affordable, and resilient sensors to be integrated towards next-generation Smart SIBs.

Next-generation batteries and U.S. energy storage: A comprehensive review: Scrutinizing advancements in battery technology, their role in renewable energy, and grid stability

This study provides a comprehensive review of next-generation battery technologies and their critical role in U.S. energy storage, particularly focusing on renewable energy integration and grid stability. The main objectives were to assess the current advancements in battery technology, evaluate their economic viability and environmental impacts, and understand the implications for stakeholders in renewable energy and grid management. Employing a systematic literature review and content analysis, the study analyzed data from peer-reviewed articles, industry reports, and government publications published between 2014 and 2024. Key findings indicate significant progress in battery efficiency, lifespan, and safety, primarily driven by innovations in lithium-ion and sodium-ion batteries. These advancements are pivotal in enhancing energy storage capabilities and facilitating the integration of renewable energy sources into the grid. However, challenges such as material scarcity, environmental concerns, and the need for improved recycling methods were identified. The study also highlights the importance of regulatory frameworks and policies in shaping the development and deployment of these technologies. Strategic recommendations for industry leaders and policymakers include focusing on sustainable material sourcing, investing in alternative battery chemistries, and implementing supportive regulatory frameworks. In conclusion, the study underscores the transformative potential of advanced battery technologies in achieving a sustainable energy future, suggesting future research directions in material development, battery chemistries, and integration with smart grid technologies.

Elevating Lithium-Sulfur Battery Durability through Samarium Oxide/Ketjen Black Modified Separator.

Lithium-sulfur batteries have garnered significant attention as a promising next-generation battery technology due to their potential for high energy density. However, their practical application is hampered by slow reaction kinetics and the shuttle effect of lithium polysulfide intermediates. In this context, the authors introduce a pioneering solution in the form of a novel porous carbon nanostructure modified with samarium oxide, denoted as Sm2O3/KB. The material has a highly polar surface, allowing lithium polysulfide to be chemisorbed efficiently. The unsaturated sites provided by the oxygen vacancies of Sm2O3 promote Li2S nucleation, lowering the reaction energy barrier and accelerating Li2S dissolution. The porous structure of Ketjen Black provides a highly conductive channel for electron transport and effectively traps polysulfides. Meanwhile, the batteries with Sm2O3/KB/PP spacers exhibited remarkable electrochemical performances, including a low-capacity decay rate of only 0.046 % for 1000 cycles at 2 C and an excellent multiplicative performance of 624 mAh g-1 at 3 C. This work opens up a new avenue for the potential use of rare-earth-based materials in lithium-sulfur batteries.

Unlocking the potential of open-tunnel oxides: DFT-guided design and machine learning-enhanced discovery for next-generation industry-scale battery technologies

Lithium–ion batteries (LIBs) are ubiquitous in everyday applications.

Mesoporous Silica Engineered Lithium Metal Batteries: Unraveling the Mechanisms behind Dendrite Inhibition and Enhanced Electrochemical Performance

Lithium metal batteries are widely considered to be a next-generation battery technology due to their high energy density, fast charging capability, and potential to power a wide range of applications, from portable electronics to electric vehicles.Compared to conventional lithium-ion batteries, which use graphite as the anode material, lithium metal batteries have the potential to offer significantly higher energy density. This is because lithium metal has a much higher theoretical capacity than graphite, meaning it can store more energy per unit weight or volume. As a result, lithium metal batteries could potentially offer longer run times and smaller form factors than lithium-ion batteries, which are already widely used in consumer electronics and electric vehicles.In addition to their high energy density, lithium metal batteries also offer fast charging capabilities. This is because the lithium metal anode can be charged more quickly than the graphite anode used in conventional lithium-ion batteries. This could enable faster charging times for electric vehicles and other applications, reducing the time required for recharging and improving their overall usability.However, one of the major challenges with lithium metal batteries is dendrite growth, which can occur when lithium metal ions deposit unevenly on the surface of the anode during charging. These dendrites are needle-like structures that can penetrate the separator and cause short-circuits, leading to reduced battery performance and safety issues. As a result, much of the research on lithium metal batteries has focused on developing strategies to prevent dendrite growth, such as using coatings or electrolytes with additives that can stabilize the lithium metal anode.Despite these challenges, lithium metal batteries continue to be a promising next-generation battery technology. Researchers are working on improving their energy density, charging speed, and safety, and they are exploring a range of applications, from portable electronics to electric vehicles and grid-scale energy storage. If these challenges can be overcome, lithium metal batteries could revolutionize the energy storage industry and enable a wide range of new and exciting applications.To address this issue, we have explored the use of various coatings on the lithium metal anode to prevent dendrite growth. In this study, ordered mesoporous silica with different pore sizes and pore structures, such as SBA-15 and KIT-6, were used as coatings between the lithium metal anode and separator.SBA-15 and KIT-6 are two types of mesoporous silica materials that are widely used in various applications due to their unique properties. The synthesis of these materials involves the use of templates to control the pore size and structure.They are synthesized using a combination of a surfactant(pluronic P123 or cetyltrimethylammonium bromide;CTAB) as the template and tetraethyl orthosilicate(TEOS) as the silica source. The synthesis involves mixing a solution of surfactant and TEOS in acidic conditions, followed by aging and calcination steps. The resulting materials have a highly ordered hexagonal pore structure(SBA-15) and body-centered cubic pore structure(KIT-6) with a pore size ranging from 5 to 20 nm.By coating the surface of the lithium metal with a uniform pore structure material such as ordered mesoporous silica, dendrite growth can be suppressed and lithium deposition can occur more uniformly.The uniform pore structure material acts as a physical barrier to lithium ion diffusion and helps to control the deposition of lithium ions onto the surface of the lithium metal. When lithium ions are deposited onto the surface of the lithium metal, they can form a layer of lithium that can grow and become thick over time. If the lithium layer is too thick, it can become unstable and form dendrites. However, the uniform pore structure material can help to limit the thickness of the lithium layer and promote the deposition of lithium ions in a more uniform manner, thus reducing the likelihood of dendrite formation.Additionally, the uniform pore structure material can help to reduce the concentration of lithium ions at the surface of the lithium metal, which is another factor that can contribute to dendrite growth. By limiting the concentration of lithium ions at the surface, the uniform pore structure material can help to prevent the formation of high-concentration regions that can promote dendrite growth.Overall, the mechanism by which a uniform pore structure material can suppress dendrite growth involves controlling the deposition of lithium ions onto the surface of the lithium metal, limiting the thickness of the lithium layer, and reducing the concentration of lithium ions at the surface. These factors help to promote more uniform lithium deposition and prevent the formation of dendrites, leading to improved battery performance and safety.

Characterizing the Cathode Degradation Process from Thermal Abuse in Solid State Batteries

With an ever-increasing reliance on batteries for all aspects of life, safety of energy storage is a growing concern as reported instances of lithium-ion battery (LIB) fires and even a solid-state battery (SSB) fire arise. However, the understanding of battery safety from a fundamental materials level is not well understood. As the push for higher energy density batteries in the electrification of transportation continues, it is imperative to understand how underlying material degradation and failure affects the safety of current and next-generation lithium battery technology.In this study, heat release and corresponding degradation due to external heating are explored for the following battery configurations: All solid-state batteries (ASSBs), SSBs containing a low amount of liquid electrolyte, and LIBs. NMC532 cathode was used in all battery configurations, Ta-doped LLZO was used for the solid electrolyte, and LiPF6 in EC/EMC was used as the liquid electrolyte in the SSB and LIB configurations. Differential scanning calorimetry (DSC) was used to raise microcells to definitive temperatures of interest depending upon their respective exotherm profile. LIB sample heat release was significantly higher than the heat release of the ASSB and SSB, even though the heating temperature range and final temperature were lower for the LIB samples. The disassembled microcell components were then analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD analysis revealed the LIB samples did not show the presence of the fully degraded rock salt crystalline phase after peak heat release, whereas ASSB and SSB configurations revealed the presence of the rock salt phase. Additionally, SEM image analysis shows no degradation of the LIB particles, while ASSB and SSB samples show surface degradation of the high temperature samples. Decomposition of NMC to the rock salt phase involves the release of oxygen, which may undergo an exothermic reaction inside the SSB. These investigations shed light into the expected extent of NMC decomposition at key temperatures and exothermic heat flow peaks for each battery composition. Future work combining these results with further elemental characterization experiments will pave the way for a materials-level understanding that can be incorporated into the initial design and development stages of next generation lithium batteries, impacting the creation of energy storage devices by ensuring commitment to safety from the ground up.

Operando 17o NMR Studies of Degradation in Li-Oxygen Batteries

Lithium-oxygen batteries are a promising next-generation battery technology, offering energy densities more than double that of the current state-of-the-art lithium-ion technology while not using transition metals in their cathodes. However, Li-oxygen battery commercialisation is hampered by short lifetimes caused by reactive oxygen species, such as singlet oxygen, that degrade the electrodes and electrolyte, resulting in a build-up of breakdown products. Even studying this breakdown is challenging as no technique can simultaneously detect and quantify all of the breakdown products, particularly in a non-destructive way. 17O NMR is ideally suited to this study as all common breakdown and discharge products form from a reaction involving oxygen gas or its derivatives. Thus, using 17O2 enriched gas leads to all the species of interest becoming enriched1 and hence detectable by NMR.Operando NMR, conducted as the cell cycles, is a powerful analysis technique offering non-invasive, quantitative, real-time measurements, often without heavy modification to the system of interest. Operando 17O NMR is particularly challenging due to 17O’s low sensitivity, broad signals and low natural abundance. We demonstrate how to overcome these challenges using sample enrichment, experimental setup and data post-processing. Specifically, we employ a double frequency sweep (DFS), Carr-Purcell-Meiboom-Gill (qCPMG) pulse sequence, a custom cell design and Gaussian processes (GP) to fit the data. These methods made monitoring degradation on the tens of minute timescales with the cell using 8mL (ca. $20) of 70% 17O2 possible. These methods can be applied to enable other 17O NMR studies, for example, of CO2 capture2, to be done in an operando manner and more broadly to other nuclei with similar NMR properties, such as sulphur in lithium sulphur batteries.We utilise these methods to separate out the chemical and electrochemical degradation occurring in the lithium-air cell by comparing a cell continuously discharged to one with “rest” periods in the discharge. Additionally, we can observe the onset of degradation mechanisms, be it at certain voltages or depths of discharge as well as species with limited lifetimes, such as H2O and CO2. This, along with ex-situ NMR measurements of electrolyte degradation caused by singlet oxygen has shed light on the fraction of degradation caused by singlet oxygen. In addition to highlighting the effect of high cell voltages on the breakdown and subsequent rapid reformation of solid breakdown products.Additives previously suggested to prevent this breakdown (LiI, dimethyl anthracene and triethylenediamine), by suppressing singlet oxygen, were tested in the cell. It was shown that while these almost entirely suppressed breakdown leading to water formation, and eventually to LiOH, they only had minor effects on the solid degradation products.It is hoped these insights can lead to the development of new and refined strategies to prevent breakdown in future cells.References1) Berge, A.H. et al. (2022) Revealing carbon capture chemistry with 17-oxygen NMR spectroscopy. Nat Commun 13, 77632) Leskes M. et al. (2013) Monitoring the Electrochemical Processes in the Lithium-Air Battery by Solid State NMR Spectroscopy J. Phys. Chem. C 117, 51, 26929–26939FigureA - In-situ cell mounted in NMR probe containing cell assemble and 17O2 gasB - Top quantification of common breakdown species, regression and error bars generated using gaussian processes. Highlighted is the breakdown of Li2CO3 at the end of the charge to produce CO2, which rapidly reacts as the start of discharge to reform Li2CO3 C - Schematic of breakdown mechanisms observed and their estimated contributions to breakdown Figure 1

(Invited) Improving Our Understanding of Conducting Polymer Binders

As lithium-ion batteries reach their intrinsic performance limits, next-generation battery technology arises that relies much more strongly on the electrode matrix. Traditional compositions of binders and conductive additives with non-polar surfaces face intrinsic obstacles in these developments. In many next-generation electrode formulations, this incompatibility reveals itself through particle disconnection, increased electrode inhomogeneity1, and conductive additive agglomeration2. Conducting polymers are an apparent solution to such problems. Conducting polymers and their composites can be designed to exhibit increased adhesion, stronger interactions with active material surfaces and electrolytes, and favorable mechanical properties, while providing electronic connectivity at the adhesive contact with the active material3. Many examples have been presented in the literature that demonstrate improved electrode performance using such composites4–6.A common form of conducting polymer composites combines an intrinsically conductive polymer (e.g. polypyrrole, polythiophene, polyaniline) with a polyelectrolyte (e.g. polacrylate, polystyrene sulfonate, carboxymethyl cellulose). This presentation discusses an exploration of some of the fundamental properties of composites of polypyrrole with carboxymethyl cellulose. The work shows intrinsically favorable properties of the composite for application in batteries7. Among those properties are that it can be easily processed in water and N-methyl-2-pyrrolidone, exhibits better adhesion to the current collector, shows competitive conductivity and distributes evenly across active materials. However, it will also be shown that the native structure of this composite is not ideal for long-range conduction and that improvement can be made to the material’s conductivity and capacitance8.Our work is targeting a more complete understanding of the properties of these composites as they are employed in battery environments. It demonstrates enormous promise for the use of conducting polymers as binders, but also gaps in our understanding of their interactions with electrolytes and active materials that need to be addressed to advance their impact on the development of next-generation batteries.

Traditional and Iterative Group-IV Material Batteries through Ion Migration

In this review, we emphasize the significant potential of carbon group element-based (Group-IV) electrochemical energy devices prepared on the basis of ion migration in the realm of high-efficiency batteries. Based primarily on our group research findings, we elucidate the key advantages of traditional Group-IV materials as electrodes in ion batteries powered by metal ion migration. Subsequently, we delve into the operational principles and research progress of iterative Group-IV material moisture ion batteries, driven by ion migration through external moisture. Finally, considering the practical challenges and issues in real-world applications, we offer prospects for the development and commercialization of Group-IV materials utilizing ion migration in both conventional and next-generation battery technologies.

High-stability room temperature ionic liquids: enabling efficient charge transfer in solid-state batteries by minimizing interfacial resistance

Currently, intensive research is underway to develop stable electrolyte systems that can significantly enhance the performance of rechargeable batteries. Recent advances in solid electrolytes have led to new types of promising systems owing to their high conductivity. This has generated considerable interest in the practical applications of safe batteries. Considering the safety concerns associated with rechargeable batteries, solid electrolytes have become indispensable for the advancement of next-generation battery technologies. However, the increased interfacial resistance at solid-solid interfaces has become a critical challenge. To address this problem, room-temperature ionic liquids (RTILs) have been investigated as functional materials for mitigating the interfacial resistance in solid-state batteries (SSBs). The special properties of RTILs, such as their non-volatility, non-flammability, and high safety characteristics, make them highly promising candidates for safe batteries. Various approaches have been explored for the effective utilization of ionic liquids in SSBs. This review provides a comprehensive discussion on the application of RTILs as electrolytes, considering their electrochemical properties and incorporation into composites to minimize resistance in SSBs.

Enabling stable and high areal capacity solid state battery with Ni-rich cathode via failure mechanism study

Sulfide based all solid state batteries (ASSBs) with Ni-rich layered oxide cathode are one of the most promising next-generation battery technologies due to their high energy density and improved safety. However, its electrochemical performance is still unsatisfactory, especially with high cathode mass loading. Herein, the failure mechanisms of single crystal LiNi0.8Co0.1Mn0.1O2 (NCM811) in ASSBs are systematically investigated from three aspects: interfacial side reactions, micro-distribution of cathode composite and mechanical failure. In addition to the commonly reported interfacial side reactions, we find micro-heterogeneity in cathode composite has detrimental effects on electrochemical performance. Three strategies are proposed and are effective to achieve excellent electrochemical performance of the batteries: ASSBs with bare NCM811 retains 88.5 % of its capacity after 2000 cycles at 1C (1C = 200 mA g–1). Moreover, ASSBs with high cathode loading of 35.7 mg cm−2 (30 °C) and 71.4 mg cm−2 (60 °C) is explored, which deliver a record-breaking areal capacity of 6.4 mAh cm−2 and 13 mAh cm−2, respectively.

(Digital Presentation) Electrocatalytic and Conductive Vanadium Oxide on Carbonized Bacterial Cellulose Aerogel for the Sulfur Cathode in Li-S Batteries

Li-S chemistry is regarded as promising next-generation battery technology. However, its complex redox process and long-chain lithium polysulfides shuttling are hindering the development of practical Li-S battery technology. To address these problems, many transition-metal-oxide-based catalysts have been investigated to chemically bind soluble lithium polysulfides and accelerate their redox kinetics. However, the intrinsic poor electrical conductivities of these oxides restrict their catalytic performance, consequently limiting the sulfur utilization and the rate performance of Li-S batteries. Herein, we report a freestanding electrocatalytic sulfur host consisting of hydrogen-treated VO2 nanoparticles (H-VO2) anchored on nitrogen-doped carbonized bacterial cellulose aerogels (N-CBC). The hydrogen treatment enables the formation and stabilization of the rutile VO2(R) phase with metallic conductivity at room temperature, significantly enhancing its catalytic capability compared to the as-synthesized insulative VO2(M) phase. We characterized the electrocatalytic performance of this unique H-VO2@N-CBC structure using several methods and found that the activation energy between S8 and polysulfides and the one between polysulfides and Li2S are largely reduced by 28.2 and 43.3 kJ/mol, respectively. Accordingly, the Li-S battery performance is greatly improved, with a high initial specific capacity of 1347 mAh g−1 at 0.1 C and remarkable cycling stability with a capacity of 758 mAh g-1 after 300 cycles at 1 C. This work provides an effective strategy for designing and fabricating conductive oxide catalysts to promote the electrochemical performance of Li-S batteries.

Rational Design of Graphene-Supported Single Atom Catalysts for High Performance Lithium-Oxygen Batteries

Aprotic lithium-oxygen batteries (LOBs) have been considered as one of the next-generation battery technologies, due to its ultrahigh theoretical energy density (~3600 Wh kg -1), 5-10 times higher than the state-of-the-art lithium-ion batteries (LIBs), supporting the development of electric vehicles (EVs). However, the battery system suffers from poor cyclability, low round-trip efficiency and inferior rate capability, mainly originated from the inertness of oxygen gas and the poor electrical conductivity of lithium peroxide (Li2O2), leading to the sluggish kinetics of oxygen reduction reaction (ORR)/ oxygen evolution reaction (OER). In response to the challenges, developing a highly efficient catalyst at the cathode is vital to boost the reaction rate and reduce the reaction overpotentials, eventually address the problem. Heterogeneous single-atom catalysts (SACs) on solid support are emerging as a new frontier in this research field. Here, we use the density of state (DFT) calculation to determine the catalytic activities of a wide range of transition metal single atoms distributing on the nitrogen doped graphene support and found that Zn-SAC exhibits the highest ORR/OER activities. We discovered that Zn-N4 moieties, functioning as catalytic centers, bind with LiO2 not very strongly, reduce the reaction overpotentials, facilitates the reaction rate and enhance the stability of the catalyst. The catalytic activity of SACs is highly correlated to the Gibbs free energy of the adsorbed LiO2. A descriptor, F of the catalysts determining the catalytic activity was developed from the metal properties of electronegativity (EN), enthalpy of vaporization (EV) and number of electrons in d orbital, by using supervised machine learning (ML) method, providing guidance for designing useful SACs in ORR/OER process. This work systematically provides guidance to design highly efficient SAC for LOBs and provides fundamental insights in choosing the proper metal for the ORR/ OER application.

(Digital Presentation) Polydopamine-Functionalized Bacterial Cellulose As Biopolymer Separator for Lithium-Sulfur Batteries

Li-S chemistry is regarded as promising next-generation battery technology, but the development of Li-S battery technology is severely impeded by the challenges of polysulfide shuttling and lithium dendrite formation. To address these issues, we coated polydopamine on bacterial cellulose (BC) to create a biopolymer separator. BC provides its dense network, while the presence of polydopamine offers dense polar functional groups to curb polysulfide shuttling by confining them in the sulfur cathode side. Such a separator, with the uniform distribution of nanoscale pores and functional chemical groups, also ensures a consistent Li+ flux at the anode surface, thus addressing the problem of lithium dendrite formation. Our results suggest that this polydopamine/BC-based biopolymer separator has superior performance over the commercial polyolefin-based separator. In particular, the Li-S batteries assembled with this biopolymer separator exhibited a specific discharge capacity of 1449 mAh/g at 0.1C and 909 mAh/g at 1C, while showing a small capacity fade of 0.023% per cycle.