Binders for Li-Ion Battery Technologies and Beyond: A Comprehensive Review

Solid-state batteries utilizing lithium metal anodes have the potential to enable batteries with a specific energy of >500 Wh/kg and an energy density of >1,500 Wh/L for thousands of cycles. When optimized they will improve the energy efficiency, operating temperature range, sustainability, and safety at a lower cost compared to projections for advanced Li-ion batteries. This improved performance is critical for the widespread adoption of electric vehicles and may enable future applications such as electric aviation. Expectations for solid-state batteries are high, there are significant materials and processing challenges that need to be overcome. Some of these challenges are well known; others are more subtle and are just becoming known. The challenges and their solutions must be clearly identified to realize high-energy solid-state Li metal batteries. In the United States, the U.S. Department of Energy (DOE) funds the majority of energy storage research and development, including solid state battery research. Web of Science publication analysis shows that worldwide DOE is second largest funder. Work on solid state batteries is distributed across different arms of DOE and is coordinated at headquarters to ensure a broad national portfolio for advanced batteries, including lithium batteries and solid-state battery devices. We note that university and national laboratory researchers in the US with a long-standing interest in solid state batteries is a small, integrated community with recognized impact for publications, patents and startup companies. The opportunity for this group to engage for research with international colleagues is growing, fostered by periodic bilateral meetings supported by DOE and by the recent joint US German research program for lithium battery interface studies. These are valuable opportunities to speed solid-state battery development. The ORNL led virtual workshop, overviewed here, confirms the community’s shared vision of the exciting advances, opportunities, and challenges. Further, we are seeing that this workshop has spawned several new informal collaborations and draft proposals. This encourages us to propose future discussion. On May 11, 2020, Oak Ridge National Laboratory (ORNL) hosted a 6-hour, on-line national workshop to discuss recent advances and most the prominent obstacles to realizing solid-state Li metal batteries. The workshop included more than 30+ experts from national laboratories, universities, and companies, all of whom have worked on solid-state batteries for multiple years. The participants shared recent advances, many not yet in print, illustrating that the community has gained significant new insights for solid-state Li battery materials over the last 5 years. In this report, the major outcomes of the workshop are organized to identify the gaps in our scientific knowledge for four core materials science areas: (1) Li metal anodes, (2) the solid electrolyte in contact with Li metal, (3) active cathode materials and solid-state composite cathodes, and (4) solid electrolytes. Illustrative examples and discussions are reported with the more comprehensive issues in the report. Discussion of additional challenges related to processing of solid-state battery materials and to the designs and architectures for mechanically robust, long-lived batteries received less attention due to time constraints. These are good themes for deeper discussion at a follow-on workshop, where a complete list of critical research topics can be identified.

The increasing need for energy, the widespread adoption of electric vehicles and renewable energy storage systems, and the search for cost-effective, reliable energy storage options are all factors in the dynamic nature of the global energy landscape and energy storage industry. As more and more people switch to using electric vehicles and other kinds of renewable energy storage, there has been a corresponding increase in demand for LIBs all around the globe. Despite increasing demand, there are geopolitical and supply-chain risks as most LIBs are still manufactured in only a few countries, namely China, Japan, and South Korea. Sodium-ion batteries, also known as SIBs, have recently come to the forefront as a potentially advantageous candidate for the large-scale storage of electric energy due to the potential advantages of widespread availability and low cost of sodium resources. SIB research and development are still at an early stage, and there are few opportunities for their commercialization. SIBs do, however, confront a number of issues that need to be addressed, including as their short cycle life and rate capability, the restricted availability of high-performance materials, and the need for more research and development to maximize their performance and dependability. Nonetheless, tremendous progress has been made recently, and several businesses and research centers across the globe are attempting to enhance SIB technology. The high theoretical specific capacity and quantity of component elements make layered metal oxides suitable cathode materials for SIBs. In order to enhance their electrochemical performance, however, further exploration is required to deal with their drawbacks, such as limited rate capability and voltage fading. As the cathode materials play such a large role in determining the energy density of SIBs, the primary issue in developing high-energy SIBs is discovering cathode materials with plentiful active sites, high reaction potential, unhindered ionic channels, and stable structures. Tailoring the morphology of materials using nanostructure engineering opens up hitherto unimagined possibilities for exploiting the functional features such as enhanced electrode's specific surface area, decreased sodium-ion diffusion distance, and boost in electronic conductivity. This study demonstrates a quaternary 1D layered transition metal oxide-based cathode with a composition of Na0.67Fe0.25Mn0.5Ti0.2V0.05O2 synthesized by a facile sol-gel strategy. From the SEM results, it is seen that 1D spoke like nanorods are evolved with a tiny fraction of 3D hexagonal lattice which is due to the excessive presence of vanadium in the stoichiometry ratio of the composite. Such nanorod framework configuration facilitates large surface area in contact with the electrolyte that is suitable for charge migration and rapid diffusion of sodium ions through short solid-state route. The P2- Na0.67Fe0.25Mn0.5Ti0.2V0.05O2 microstructure, with its high crystallinity and nanorod structure, showed off a high specific capacity and outstanding rate capability which is visible through electrochemical analysis results.

<p indent="0mm">In order to deal with the increasingly severe global energy crisis as well as serious environmental pollution, it is urgent to develop new energy resources. Although lithium-ion batteries have only been successfully introduced into the market since 1990s, there is still an exponentially growing demand for lithium-ion batteries all over the world. As a considerable novel energy source, lithium-ion batteries have significant potential, which is widely used in electric vehicles, energy-storage systems, metallurgy, ceramic production, glass manufacturing and aviation fuel industries. Among them, the solid-state lithium-ion batteries (SSLIBs) represent a promising evolution in battery technology, offering superior safety, energy density, and longevity compared to conventional liquid electrolyte batteries. Traditional lithium-ion batteries, which use liquid electrolytes, suffer from safety issues such as leakage, flammability and thermal runaway. SSLIBs replace these liquid electrolytes with solid electrolytes, mitigating these risks and enabling higher energy densities due to the ability to accommodate lithium metal anodes. The SSLIB consists of a positive electrode, a negative electrode and a solid electrolyte. Compared with liquid electrolytes, solid electrolytes avoid the direct contact between positive electrodes and negative electrodes, fundamentally eliminating the risk of lithium dendrites piercing the separator, so as to enhance the safety of lithium batteries greatly. Furthermore, the SSLIBs are expected to be a hot spot in future lithium battery research due to the advantages of high energy density, wide operating voltage range and long cycle life. Advancements in SSLIBs technology are crucial for the next generation of electric vehicles, portable electronics, and large-scale energy storage systems, pushing the boundaries of battery performance, safety and sustainability. Solid electrolytes are regarded as the key component of SSLIBs, serving dual functions as both separators and electrolytes. The currently developed solid electrolytes can be divided into two categories: Polymer solid electrolytes and inorganic solid electrolytes, in which the oxide solid electrolytes, as the earliest developed inorganic solid electrolytes, play an indispensable role in the development of solid-state battery industry. The typical oxide solid electrolytes, including sodium super ionic conductor (NASICON), garnet (LLZO), inorganic perovskite (LLTO), and LiPON films, are reviewed in this paper. NASICON, for example, is known for its high ionic conductivity and structural stability. Garnet-type electrolytes, such as LLZO, possess high ionic conductivity and chemical stability with lithium. Inorganic perovskite (LLTO) provides a good balance between ionic conductivity and mechanical strength. LiPON films, widely used in thin-film batteries, have excellent electrochemical stability and compatibility with lithium metal. In addition, the crystal structures and ion-transport mechanism, the solutions to improve conductivity and measures to improve the compatibility between electrodes and electrolytes are introduced, along with a comparation of oxide solid electrolytes. Finally, several suggestions for future development directions are proposed. These include enhancing the ionic conductivity of solid electrolytes, improving the interface compatibility between the electrolytes and electrodes, and developing cost-effective and scalable manufacturing processes. Additionally, further research is needed to understand the degradation mechanisms and long-term stability of solid-state batteries. These recommendations aim to provide a more comprehensive reference for ongoing and future research on oxide solid electrolytes, supporting the broader goal of advancing solid-state lithium battery technology.

Research on solid-state batteries began in the 1950s to address issues that stem from the liquid electrolyte, such as electrolyte leakage. Today, with implementation of batteries in larger systems like electric vehicles or the grid, the performance demands are greatly increased, which compounds the safety issues associated with electrolyte decomposition. In solid state batteries, a solid electrolyte is utilized, which eliminates the use of flammable, organic solvents in the cell. Solid state electrolytes transport ions with better selectivity than liquid electrolytes, which reduces unwanted side reactions. Liquid electrolyte decomposition can also accelerate passivation of the solid/electrolyte interface1. Solid-state batteries may be the key to the development of safe lithium batteries. Lithium batteries are exciting next generation energy storage as lithium anodes have the most negative potential of any known material, which enables lithium anodes to have a high energy density and high discharge voltage. However, lithium batteries suffer from many issues that have prevented their widespread commercialization as rechargeable cells. When lithium metal batteries are cycled, the anode is used non-uniformly which leads to the development of finger-like dendrites. Dendrite formation leads to cell short circuits, higher rates of adverse reactions, and large volume changes. These problems are major safety issues but also account for the low Coulombic efficiency and poor cycling performance2. The utilization of all-solid-state cells for lithium batteries can reduce the growth of dendrites3, which greatly improves safety2. However, solid-state batteries suffer from high resistances at ambient temperatures. Wu et al.4 studied an all-solid-state battery composed of a lithium foil anode and a cathode made of lithium ferric phosphate (LFP) particles in a block copolymer matrix. In the cathode, the electronic conduction is facilitated by a conducting polymer, poly(3-hexylthiophene) (P3HT). The conductivity of this semiconductor polymer depends on the electrode potential because the conducting polymer is oxidized and reduced when transporting the electrons. The electronic conductivity of the cathode polymer matrix without the LFP active particles was measured as a function of the voltage, and this experimental fit was used with a macro-homogeneous continuum model developed by Newman and associates5,6. The model output was relatively independent of the rate and failed to capture the trend of the experimental data. The authors then reduced the electronic conductivity until the best agreement between the experimental data and the model was achieved4. This talk explores the possibility of obtaining better fits for the model predictions by performing detailed estimation of different parameters that affect the performance of the system by combining different/robust simulation and estimation methods. Acknowledgments The authors are thankful for the financial support from the Battery 500 Consortium and the Clean Energy Institute (CEI) at the University of Washington. References Takada, K., AIP Conf. Proc., 1765, (2016).Cheng, X. B., Zhang, R., Zhao, C. Z. & Zhang, Q., Chem. Rev., 117, 10403–10473 (2017).Kim, J. G. et al., J. Power Sources, 282, 299–322 (2015).Wu, S.-L., Javier, A. E., Devaux, D., Balsara, N. P. & Srinivasan, V. J., Electrochem. Soc., 161, A1836–A1843 (2014).Newman, J. S. & Tobias, C. W., J. Electrochem. Soc., 109, 1183 (1962).Doyle, M., Fuller, T. F. & Newman, J., J. Electrochem. Soc., 140, 1526 (1993).

All-solid-state batteries (ASSBs) are poised to meet the rising demand for high energy density electrochemical energy storage and safety in lithium-ion battery technology, a crucial aspect for the widespread adoption of electric vehicles [1]. However, the solid-electrolyte interphase (SEI) layer arising from chemical incompatibility and a narrow solid electrolyte electrochemical window poses a significant hurdle. The SEI contributes high resistance to ion transfer resulting in poor performance and cyclability of promising solid-state electrolyte materials [1]. Therefore, probing interfacial properties between the lithium and solid-state electrolyte is paramount to assess the interfacial changes that adversely impact battery performance through multiple charge–discharge cycles [2]. According to a review from Paul et al. there have been several studies characterizing the chemical composition of the SEI in ASSBs, but there is limited evidence probing the Li-SSE interphase structure [3]. Structural properties impact interfacial transport and are difficult to assess due to the limited quantity of material available for examination and for the “buried” nature of the interphase [4]. We implemented a Li/Li symmetric cell system to isolate the interactions between lithium and an argyrodite (Li6PS5Cl) solid electrolyte. To understand and quantify the structure of reaction layers that form and evolve at Li-SSE interfaces during cycling, we have performed interface-sensitive operando transmission X-ray Diffraction (XRD) experiments with high energy, high flux synchrotron radiation. Electrochemical cycling and electrochemical impedance spectroscopy paired with XRD measurements quantified SEI formation, degradation, and specific resistance contributions. Our results show evidence for crystalline reaction layers that evolve with time and potential providing insight into the formation and evolution of dominant crystalline phases throughout the interphase region.References Yu, C., Ganapathy, S., Eck, E.R.H. et al. Accessing the bottleneck in all-solid state batteries, lithium-ion transport over the solid-electrolyte-electrode interface. Nat. Commun. 8, 1086 (2017). https://doi.org/10.1038/s41467-017-01187-y Bhaway, S. M.; Qiang, Z.; Xia, Y.; Xia, X.; Lee, B.; Yager, K. G.; Zhang, L.; Kisslinger, K.; Chen, Y.-M.; Liu, K.; Zhu, Y.; Vogt, B. D. Operando Grazing Incidence Small-Angle X-ray Scattering/X-ray Diffraction of Model Ordered Mesoporous Lithium-Ion Battery Anodes. ACS Nano 2017, 11 (2), 1443– 1454, DOI: 10.1021/acsnano.6b06708 P. Paul, B.-R. Chen, S.A. Langevin, E.J. Dufek, J. Nelson Weker, J.S. Ko. Interfaces in all solid state Li-metal batteries: A review on instabilities, stabilization strategies, and scalability. Energy Stor. Mater. 45 (2022), pp. 969-1001, 10.1016/j.ensm.2021.12.021 Tan, S., Kim, JM., Corrao, A. et al. Unravelling the convoluted and dynamic interphasial mechanisms on Li metal anodes. Nat. Nanotechnol. 18, 243–249 (2023). https://doi.org/10.1038/s41565-022-01273-3

The global transition to sustainable energy systems demands high-performance batteries, yet the inherent safety limitations of lithium-ion batteries (LIBs)—particularly thermal runaway driven by flammable liquid electrolytes—pose critical barriers to widespread adoption in safety-critical applications. This review conducts a comprehensive, evidence-based comparative safety assessment of three pivotal battery technologies: incumbent LIBs, emerging sodium-ion batteries (SIBs), and solid-state batteries (SSBs). We establish a detailed safety baseline for LIBs, examining failure mechanisms under thermal, electrical, and mechanical abuse conditions, including thermal runaway progression (T 1 , T 2 , T 3 ), gas evolution profiles, and cell-to-cell propagation dynamics. SIBs demonstrate significant safety improvements through higher thermal runaway initiation temperatures (220–260 °C vs. 170–220 °C for NMC LIBs), reduced heat release rates, lower hydrogen content in off-gases (30 % vs. 42 % for LFP), and transformative zero-volt transport capability. SSBs, particularly oxide-based variants, represent a paradigm shift by eliminating flammable liquid electrolytes, achieving exceptional thermal stability (T 2 > 600 °C), minimal gas evolution (<0.5 L/Ah), and dramatically slower propagation rates (0.3–0.9 °C/min vs. 9–11 °C/min for high-Ni NMCs). However, application-specific safety rankings reveal critical nuances: LFP's superior thermal stability is offset by severe HF toxicity (3000–8000 ppm), while sulfide SSBs present conditional H 2 S risks upon moisture exposure. This analysis demonstrates the evolution from 'engineered safety'—relying on external protective systems—towards 'intrinsic safety' integrated into core battery chemistry and architecture, providing actionable guidance for technology selection across diverse deployment scenarios from electric vehicles to grid-scale energy storage. • Battery safety rankings are not universal but highly application-scenario dependent. • Sodium-ion batteries show superior toxicity profiles and safe zero-volt transport. • Oxide solid-state batteries eliminate flammable electrolytes for intrinsic safety. • LFP batteries emit high HF levels, challenging their "safest chemistry" perception. • Sulfide solid-state batteries might pose H 2 S toxicity risks upon moisture exposure.

Due to the hidden benefits such as the possibilities to make energy density high, safety improved, and lifespan extended, solid-state batteries are a focal point in battery technology research. Current liquid electrolyte-based lithium-ion batteries, despite their maturity, have inherent issues like safety risks and limited energy density. While the advancement in solid-state battery technology can potentially overcome certain challenges, it also encounters its own issues including high contact interface impedance and ion transmission efficiency. For solid-state batteries to supplant traditional lithium-ion batteries in the future, these challenges must be addressed. The research provides an in-depth analysis of the three major types of solid-state electrolytes currently prevalent in the market, including oxide, sulfide, and polymer electrolytes. This is especially true for the electrochemical analysis of batteries after the electrolyte has been used. Each has its unique properties, synthesis methods, and limitations. Oxide electrolytes excel in high-temperature ionic conductivity but underperform at room temperature. Moreover, the synthesis of oxide solid electrolytes requires fine control over temperature and atmosphere, thus demanding high technical expertise. The sulfide category shows promise in room temperature conductivity, albeit with stability issues. Polymer electrolytes, however, are flexible and processable but have generally lower ionic conductivity. To enable large-scale applications, future research needs to focus on improving these electrolytes’ performance and developing cost-effective and efficient synthesis methods. The importance of research into solid-state lithium-ion batteries is tied to their capacity to transform the energy storage sector.

The widespread adoption of electric vehicles using advanced battery technologies and the development of their manufacturing base in the United States are critically important for the US economy and therefor a major focus of research and development sponsored by DOE’s Office of Energy Efficiency and Renewable Energy. Materials development is often touted as the most important enabling activity, however in a rank of major cost items, manufacturing costs ranks just below the cathode components. In addition to the need to reduce costs, US R&D should also focus on new, yet-to-be-scaled processing technologies that, when developed and implemented in the US provide both a strong component of US energy security and US-based employment in the production of electric vehicle batteries. This presents a major economic opportunity to the USA, as the global electric vehicle market is expected to grow to over $100 billion in the next ten years. Advances in battery processing science and technology could lead directly to the displacement of the established non-US-based manufacturing base via creative destruction--new innovative technologies lead to new manufacturing facilities, facilities that could be built and run in the USA. Processing science and engineering has traditionally been underrepresented in federally funded electrochemical energy storage R&D. Over the last nine years, the Vehicle Technologies Office (VTO) has been building an advanced processing R&D portfolio. This includes competitively funded research at universities, small businesses, and large corporations as well as programs supported across the national laboratory complex. Processing science and technology projects organize into two general activities: scaling-up materials production and developing innovative electrode fabrication approaches. This presentation will provide an overview of the sub-program’s history and several example successes. Future research directions and scenarios for possible funding opportunities will also be discussed.

Electric vehicles (EVs) have gained significant attention in recent years due to their potential to reduce greenhouse gas emissions and improve energy efficiency. An EV’s main source of power is its battery, which plays a crucial role in determining the vehicle’s overall performance and sustainability. The purpose of this paper is to examine the advancements in battery technology associated with EVs and the various charging standards applicable to EVs. Additionally, the most common types of automotive batteries are described and compared. Moreover, the application of artificial intelligence (AI) in EVs has been discussed. Finally, the challenges associated with EV battery development, as well as suggestions for improvement, are discussed. According to the study, Lithium-ion batteries are the most common in EVs due to their high energy density, long lifespan, and cost-effectiveness, despite their temperature sensitivity. Other battery types, like lead-acid and nickel-based, vary in efficiency, but are less commonly used in modern EVs. Solid-state batteries are seen as the future for their higher energy density and faster charging, though they face challenges like flammability. Wireless charging technology, still in development, promises superior convenience and sustainability than traditional methods. AI improves EV performance through enhanced battery management, autonomous driving, vehicle-to-grid communication, etc. Overcoming challenges like battery recycling, metal scarcity, and charging infrastructure will be crucial for the widespread adoption of EVs. This will be supported by government policies and battery technology innovations.

The transition toward carbon neutrality has accelerated the adoption of electric vehicles and large-scale energy storage systems, predominantly powered by lithium-ion batteries. However, concerns over the limited lithium resources necessitate exploring alternative battery systems. Sodium-ion batteries stand out due to the abundant supply and economic feasibility of sodium compared to lithium.This study focuses on developing high-capacity anode materials for sodium-ion batteries through the design of heterostructured composites. By combining conversion- or alloy-based active materials with a porous silicon oxycarbide (SiOC) nanocoating layer, we aim to address challenges such as volume changes, sluggish kinetics, and interfacial instability during battery cycling. Heterostructured composite anodes with a SiOC-based nanocoating layer were synthesized via controlled dispersion of precursors in silicon oil followed by heat treatment. Comprehensive physicochemical and electrochemical characterization, along with post-mortem analysis, elucidated how the heterostructure influenced battery performance. Our findings demonstrate improved electrochemical stability and enhanced sodium storage capacity attributed to the unique architecture of the heterostructured composites.This novel approach offers promising prospects for developing advanced anode materials capable of significantly enhancing the energy density and overall performance of sodium-ion batteries, thereby contributing to sustainable energy storage solutions for future applications in electric vehicles and grid-scale energy storage systems.

Sodium-ion batteries are emerging as a promising alternative to traditional rechargeable batteries, such as lithium-ion and lead-acid batteries. One of the most significant advantages of sodium-ion technology is that it utilizes materials that are not only cost-effective but also environmentally friendly. The raw materials needed to produce sodium-ion batteries are widely available, leading to reduced supply chain risks and potential price volatility often associated with lithium resources. Furthermore, the transition in energy storage mechanisms and manufacturing techniques from lithium-ion batteries is seamless since the two technologies facilitate a relatively smooth integration into existing production methods, which can lead to substantial cost savings for manufacturers. As the demand for energy storage continues to grow, the shift towards sodium-ion technology represents not just an innovation but also a practical move in battery production. Among the various cathode materials being researched for sodium-ion batteries, sodium lithium manganese oxides (NLM) have garnered attention for their potential. They exhibit good capacity and energy density; however, one of the critical challenges in their application is the Jahn-Teller distortion. This phenomenon occurs during cycling due to the changes in the valence state of manganese within the structure. As the battery operates, this distortion can lead to irreversible phase changes, compromising the structural integrity of the material and diminishing its capacity over time. To address these challenges, we investigate the role of fluorine content in enhancing the structural stability and electrochemical characteristics of (Co, F)-co-doped NLM cathode materials. By incorporating fluorine into the material's composition, we reveal that the effect of Jahn-Teller distortion can be mitigated. This modification not only helps preserve the capacity of the battery over multiple cycles but also improves the overall electrochemical performance of the cathodes. The results underscore the effectiveness of co-doping strategies, combining both cationic (like cobalt) and anionic (like fluorine) ions, to enhance the properties of electrode materials. This approach could hold the key to unlocking better performance in sodium-ion batteries, ultimately contributing to the development of next-generation energy storage solutions that are more efficient and sustainable. In summary, the advances in sodium-ion battery technology signal a significant step forward in energy storage systems. By tackling the limitations of existing materials and optimizing their composition, researchers are paving the way for viable alternatives to lithium-ion technology, thereby promoting a more sustainable and cost-effective energy future.

Owing to the fast development of portable electronics and electric vehicles, the need for electrochemical energy storage has increased. Among various electrochemical energy storage devices, lithium ion batteries (LIBs) have been demonstrated as one of the most successful examples in many electric applications. Because of their distinguished features, LIBs have high energy density and good power performance. However, due to its limited resource, its price will grow high if LIBs are progressively used. In this regard, sodium ion batteries (SIBs) have been considered as a promising alternative due to its abundance source in earth crust. Due to its similar insertion chemistry, sodium can directly transform well-established electrode materials in LIBs to SIBs. Unlimited efforts have been devoted to find new anode materials for high performance SIBs, including carbonaceous materials, metal oxides and sulfides, and alloy-based materials. Recently, elemental phosphorus P has been found to be electrochemically active for sodium ion battery anode, forming sodium phosphide (Na3P). It gives a high theoretical specific capacity of 2,597 mAh/g. But, its electrochemical performance is unsatisfactory because phosphorus has a very low electrical conductivity (~10-14 S/cm) and suffer from structural pulverization problem caused by its large volume change. To overcome this problem, Sn4P3 material has been reported as a promising anode for SIBs. It has been recently reported that Sn4P3 showed a synergistic Na-storage reaction where Sn and P atoms can react with Na to form Na15Sn4 and Na3P, and that the resulting Na15Sn4 alloy acts as a conducting pathway to activate the reversible Na-storage reaction of low electrical conductive Na3P particles. Also, Sn4P3 anode material exhibits a high reversible capacity of 1,230 mAh/g. The architecture of a stable and robust protective layer on the metallic Sn anode is critically important to ensure the good electrochemical performance of SIBs. Up to now, most of SIBs anodes consisting of elemental P and Sn alloys are generally produced by ball milling, thus the morphology has not been controlled. Ball milling method have been widely used as SnxPy electrodes because their phases can be easily controlled in laboratory scale synthesis. However, ball milling method for SnxPy is usually hard to control the morphology and produce nano scale, which leads to the deterioration of an active material resulting in capacity decay by several cycles. Therefore, hydrothermal method has received significant attention because it can control the nanoscale morphology for improved electrochemical performance. Herein, we report the porous Sn4P3-C nano spheres synthesized by hydrothermal process as an anode for SIB with an ultra-long term cycle stability and a high capacity. First, SnO2 nano spheres was synthesized by hydrothermal method with glucose precursor. Glucose not only prevents the rapid precipitation of colloidal SnO2 nano spheres but also serves as a carbon precursor for SnO2-C nano spheres. Consecutively, reduction process from SnO2 to Sn was conducted. The SnO2 redox process under hydrogen atmosphere has a significant problem. The reduction of SnO2 at 600 °C generates a liquid metallic tin, which aggregates into Sn particles. To prevent this problem, we employed a thick carbon layer coating to prevent the aggregation. Finally, phosphorization process was carried out using solvothermal method. Compared with other methods, the solvothermal route is convenient, simple, mild, and the morphology can also be controlled. With suitable temperature and time, Sn nano spheres were chemically transformed into Sn4P3 nano spheres, resulting in porous Sn4P3-C nano spheres. The synthesized porous Sn4P3-C nano sphere electrode exhibited an ultra-long cycle stability (about 2,000 cycles at 2,000 mAh/g) and high reversible capacity (700 mAh/g after 100 cycles at 200 mA/g) (Fig. 1). And its original morphology is apparently retained and the characteristic sphere geometry was unchanged after cycling test. We suggest the design strategy for the next-generation SIBs, and it can be applied to other phosphorus-metal alloying composites. Figure 1

The demand for extremely fast-charging (XFC, ≤10-min) lithium-ion batteries (LIBs) is rapidly increasing to accelerate the widespread adoption of electric vehicles (EVs). However, achieving XFC remains a critical challenge, particularly in EV-relevant cell configurations that utilize thick electrodes and high energy densities. In such cells, conventional carbonate-based electrolytes suffer from sluggish Li+ transport and unstable interfaces, leading to severe Li plating and rapid capacity decay. Overcoming this XFC bottleneck requires engineering the electrolyte system to enable both fast Li+ transport and low-resistance interface formation.In this study, we report a molecularly engineered Li+ microenvironment realized through a methyl acetate (MA)-based high-concentration electrolyte (HCE) formulated with a fluoroethylene carbonate (3MF). Compared to a dimethyl carbonate (DMC)-based HCE, the smaller and more polar MA molecules form compact solvation clusters and a softer solvation sheath, which acts as molecular lubricants, promoting Li+ percolation through the electrolyte bulk phase. As a result, despite its high salt concentration, the 3MF electrolyte exhibits much higher ionic conductivity than conventional carbonate-based electrolytes. Furthermore, the high salt concentration induces an anion-rich Li+ coordination environment, which efficiently facilitates the Li+ desolvation process. Additionally, the anion/3MF co-derived SEI ensures low energy barriers for Li+ migration across the SEI.This 3MF electrolyte enables outstanding XFC cycling performance in graphite||NMC622 cells, retaining 98.4% capacity after 500 cycles at 10 C (6-min charging) with moderate electrode loading (3.0 mAh cm–2), and further demonstrates stable long-term cycling at 6 C with high loading (6.0 mAh cm–2), representing one of the few demonstrations of high-energy Li-ion cells capable of enduring over 500 XFC cycles without degradation. These findings highlight the critical role of solvation-level molecular design in overcoming the conventional trade-offs between fast charging and energy density, offering a viable path toward practical, high-performance XFC Li-ion batteries.

Accelerating vehicle electrification is critical in combating the global climate crisis. [1-2] A major strategy to drive the widespread adoption of electric vehicles (EVs) is by enhancing the energy density of lithium batteries, which directly extends the driving range per charge. [3-4] Lithium metal batteries (LMBs), with their lithium metal anodes providing low electrochemical potential and high specific capacity, hold great promise as next-generation EV batteries due to their significantly higher energy density. [5-6] However, the current carbonate-based electrolytes used in lithium-ion batteries (LIBs) are not compatible with lithium metal anodes, resulting in rapid capacity loss and serious safety hazards, particularly from lithium dendrite formation. [7-8] As a result, the development of new electrolyte systems that support stable lithium plating/stripping and enhance safety is essential for the successful commercialization of LMBs.Herein, we introduce a new electrolyte system using dicarbonyl solvents for LMBs. Among the various dicarbonyl solvents investigated, dimethyl dicarbonate (DMDC) stands out as the most promising candidate. Interestingly, despite its structural resemblance to monocarbonyl solvents, DMDC shows stronger solvent coordination at the same lithium-to-carbonyl ratio. This results in the formation of a more stable solid-electrolyte interphase (SEI) and enhances the electrolyte's anodic stability. In most electrolyte systems, solvation energy is primarily driven by enthalpy, but DMDC's bidentate structure introduces a significant role for entropy, as Li+-DMDC complexes release fewer free molecules. When paired with the non-solvating co-solvent TTE, which reduces the electrolyte’s viscosity, the DMDC-TTE system provides highly stable cycling of the lithium anode by modulating solvation entropy. This reveals a new strategy for tailoring functional electrolyte systems.Reference: Thackeray, M. M.; Wolverton, C.; Isaacs, E. D., Energy Environ. Sci. 2012, 5 (7), 7854.Goodenough, J. B.; Park, K.-S., Am. Chem. Soc. 2013, 135, 1167.Schmuch, R.; Wagner, R.; Hörpel, G.; Placke, T.; Winter, M., Energy 2018, 3, 267.Li, ; Lu, J.; Chen, Z.; Amine, K., Adv. Mater. 2018, e1800561.Tarascon, J.-M.; Armand, M., Nature 2001, 414, 359.Armand, M.; Tarascon, J.-M., Nature 2008, 451, 652.Li, X.; Zheng, J.; Ren, X.; Engelhard, M. H.; Zhao, W.; Li, Q.; Zhang, J.-G.; Xu, W., Energy Mater. 2018, 8 (15), 1703022.Cheng, X. B.; Hou, T. Z.; Zhang, R.; Peng, H. J.; Zhao, C. Z.; Huang, J. Q.; Zhang, Q., Mater. 2016, 28 (15), 2888.

Towards greener energy storage: Brief insights into 3D-printed anode materials for sodium-ion batteries