Propylene carbonate (PC) is a promising electrolyte solvent with a wide liquid-phase temperature range, which can improve the wide-temperature performance of lithium-ion batteries (LIBs). Unfortunately, PC easily co-intercalates into graphite (Gr) interlayers with Li+ and leads to the exfoliation of the Gr structure. Herein, we demonstrate that an anion-rich artificial solid electrolyte interphase (SEI) on the surface of Gr, constructed by the polymeric ionic liquid (PIL) solid polymer electrolyte (SPE), can significantly suppress co-intercalation of the PC solvent, so that the Gr electrode can adequately work in PC-based electrolytes. This is mainly owing to the PIL SPE layer, which provides a high local concentration of TFSI- anions and selectively excludes the solvent-separated ion pair (SSIP) configuration of Li+-PC from entering the graphite interface. Meanwhile, a robust anion-derived inner SEI layer can be formed on the Gr surface through the preferential decomposition of anions. Therefore, the PIL SPE layer can effectively achieve highly reversible lithiation/delithiation of the Gr electrode in a a PC-based electrolyte. Consequently, the Gr||LiNi0.5Co0.2Mn0.3O2 (NCM523) pouch cell with a a PC-based electrolyte exhibits a high capacity of 3060 mAh, an extremely high CE of approximate to 100%, and good cycling stability with 97.1% capacity retention after 200 cycles. Acceptable rate capability and good low-temperature performance at -20 degrees C are also achieved in this pouch cell.

All-solid-state batteries (ASSBs) with silicon (Si) anodes offer great potential for high energy density and safety. Although long cycling life can be obtained at a low current density, the fast-charging capability of Si anode is hindered by the short circuit, which reason is unclear. Herein, the kinetic limit leading to the short circuit is probed and identified to be the slow charge transfer rather than the Li+ transport in Si anode bulk. The addition of excess conductive carbon can increase the Si anode's electronic conductivity and thus enhance the ASSBs' rate performance but at the expense of reducing the energy density. To resolve this, a micro-size Li-Al alloy is proposed to replace the conductive carbon and construct an all-electrochemical-active Si anode, which demonstrates several merits such as increasing the reaction kinetics (up to 8.1 mA cm‒2), providing extra capacity, and enhancing mechanical stability during cycling. As a result, the Si||NCM811 ASSBs (N/p = 1.2) achieve a high initial coulombic efficiency of 89.3%, high area capacity of 6.7 mAh cm‒2, and stable cycling over 850 cycles with capacity retention of 80.5% at 1C. This work figures out the underlying kinetic reason for the Li dendrites growth and guides to achieving high-performance ASSBs.

The development of lithium-ion battery cathode materials with higher energy density and longer cycle life is critical for advanced energy storage systems. Layered oxides are promising candidates due to their high theoretical capacity, superior cycling stability, and cost-effectiveness. However, conventional polycrystalline cathodes exhibit severe performance degradation under prolonged cycling and high-voltage operation, necessitating innovative material design strategies. Single-crystal materials, characterized by their well-defined morphological features, demonstrate distinct advantages including enhanced mechanical stability, low surface area, reduced grain boundary density, and exceptional cycling stability, effectively suppressing crack propagation and parasitic side reactions during electrochemical cycling. Nevertheless, challenges persist in single-crystal systems, including limited lithium-ion diffusion kinetics and intragranular crack formation. This review systematically summarizes the characteristics of single-crystal materials from four key aspects: synthesis methodologies, morphological control, electrochemical performance advantages, and modification strategies, establishing fundamental principles for rational material design. This work further extends the discussion to Na-ion battery systems, demonstrating the universal applicability of single-crystal engineering across battery chemistries. Finally, we outline future research directions for engineering high-performance single-crystal cathode materials, providing actionable insights for next-generation energy storage systems.

The commercialization of liquid lithium-ion batteries has revolutionized the consumer electronics industry. However, conventional lithium-ion batteries with graphite anodes and organic electrolytes are approaching their intrinsic performance limits and struggle to meet the growing demands for higher energy density, reliability, and safety in electric vehicles and large-scale energy storage. Solid-state batteries utilizing lithium or sodium metal anodes are considered promising next-generation energy storage solutions. Despite this potential, the formation of dendrites during charge–discharge cycling remains a critical challenge. Dendrite growth can initiate a destructive feedback loop of crack propagation and further dendrite intrusion, ultimately leading to battery failure and performance degradation. Previous studies have predominantly focused on single physical domains, such as electrochemical, stress, or thermal fields. However, such single-physics approach limits the understanding of dendrite evolution under realistic, coupled multiphysics conditions. This review first compares the morphological characteristics of dendrites in liquid and solid-state metal batteries. It then critically examines the key factors and predictive models of dendrite formation, initially from single-physics and subsequently from an integrated multiphysics perspective. Finally, strategies for mitigating dendrite growth via multiphysics field regulation are summarized. By establishing a comprehensive framework that integrates morphology evolution, multiphysics modeling, and suppression strategies, this work provides a foundational theoretical understanding for addressing dendrite formation in solid-state lithium and sodium metal batteries.

This study investigates a strategy to simultaneously enhance oxygen and cationic (Ni) redox reactions in Li2MnO3-based Li-rich cathode materials composed of LiNi0.5Mn0.5O2 (LNMO) and Li2MnO3 phases. It is demonstrated that high-temperature synthesis, particularly at 900 degrees C, promotes stabilization of the LNMO-like phase over the Li2MnO3-like phase, enabling concurrent activation of both redox reactions. The increased fraction of the LNMO-like phase significantly enhances the Ni redox reaction and raises the average discharge voltage. At the same time, the LNMO-like phase stabilization increases Ni incorporation into the Li2MnO3-like phase, which is crucial for activating the oxygen redox reaction. As a result, the material synthesized at 900 degrees C can achieve both high capacity and elevated discharge voltage. Additionally, the ratio of Li2MnO3 to NiO at 900 degrees C strongly influences redox reactions through its effect on the LNMO-like phase stabilization. While increasing NiO amount almost linearly enhances the Ni redox reaction, the oxygen redox reaction depends primarily on the Ni content incorporated into the Li2MnO3-like phase rather than its quantity. Therefore, simultaneous optimization of both redox reactions is achieved only within a specific compositional range, which can achieve certain amount of the Ni into the Li2MnO3-like phase. These findings demonstrate the phase stabilization control as an effective design strategy for high-energy-density Li2MnO3-based Li-rich layered materials.

Even though oxide solid electrolytes (SEs) have several advantages such as high chemical/thermal stability over conventional liquid electrolytes, their low ionic conductivity and difficult integration during cell fabrication hinder practical application. Here, the Li ionic conductivity of the LISICON (lithium super ionic conductor)-type SE is enhanced by substitution of Ge, achieving conductivity approximately 5 times higher than that of the unsubstituted. The Ge substitution can not only increase the concentration of Li but also enhance partial occupancies of Li at specific sites, enabling additional Li diffusion pathways and thereby leading to high ionic conductivity. Surprisingly, unlike other Ge-based solid electrolytes, the Ge-substituted LISICON-type SE exhibits excellent wetting behavior with Li metal and co-sintering capability with high-capacity cathodes even at temperatures above 700 degrees C. The increased Li ionic conductivity and excellent co-sintering capability enable the fabrication of an all-solid-state battery (ASSB) with an ultra-thick composite electrode (similar to 140 & micro;m), which delivers high electrochemical activity/reversibility at room temperature without external pressure. These findings clearly demonstrate that the LISICON-type SE with enhanced Li ionic conductivity provides a completely novel strategy for achieving high energy density in ASSBs and offers a promising route toward practical application of oxide-based SEs in high-energy density ASSBs.

The practical application of lithium metal batteries (LMBs) requires electrolytes that simultaneously ensure high safety and interfacial stability. Although locally concentrated ionic liquid electrolytes (LCILEs) exhibit exceptional electrochemical stability and compatibility with electrode electrolyte interfaces (EEIs), two major challenges persist: (i) safety risks caused by excessive low-flash-point diluents, and (ii) insufficient understanding of how diluents modulate solvation structures. Herein, we introduce a low-diluent-content LCILE system composed of lithium bis(fluorosulfonyl)imide (LiFSI) salt, Nmethyl-N-propyl-pyrrolidinium bis(fluorosulfonyl)imide (Pyr13FSI) ionic liquid, and trifluoromethanesulfonate (TFS) diluent. The TFS diluent strengthens ion-ion interactions by lowering the dielectric constant of the electrolyte, resulting in the formation of a unique nanometric anion aggregates (N-AGGs) reinforced solvation structure. These large anionic clusters exhibit accelerated redox decomposition kinetics, facilitating the rapid formation of a thin, dense, and low-impedance EEI. Consequently, the Li/ LiNi0.6Co0.2Mn0.2O2 coin cell achieves 87.8 % capacity retention over 300 cycles at 4.3 V, while a practical 1.4 Ah Li/NCM622 pouch cell retains 84.5 % capacity after 80 cycles at 4.5 V. Furthermore, the electrolyte demonstrates exceptional safety, and 2 Ah Li metal pouch cells successfully pass rigorous nail penetration tests without any ignition or explosion. This work not only provides a design strategy for intrinsically safe and high-performance electrolytes but also highlights the critical role of anion cluster decomposition kinetics in shaping EEI formation. (c) 2025 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Locally concentrated ionic liquid electrolytes (LCILEs) are promising electrolyte systems for lithium metal batteries (LMBs) due to their robust anion‐derived solid electrolyte interphase (SEI) and compatibility with Ni‐rich cathodes. Low‐halogen‐content chlorides, with low price and weakly coordinating ability to Li + , emerge as exceptional candidates for diluents in LCILEs. Here, it is demonstrated that the anti‐reduction capability of chloride‐based diluent in LCILEs significantly affects the stability of the Li anode. Typically, 1,4‐dichlorobutane (DCB14) and 1,5‐dichloropentane (DCP15) possess high electrophilicity, making them susceptible to electron attack and prone to severe side reactions with Li metal anode. In contrast, 2,2‐dichlorodiethyl ether (DCDEE), where an oxygen atom replaces the central carbon atom in DCP15, demonstrates excellent reduction stability as it constitutes an electron‐rich system with low electrophilicity. In LCILE with DCDEE diluent, the weak coordination interaction of DCDEE facilitates Li + ion transport, while the resulting dual‐halide LiF/LiCl hybrid electrode‐electrolyte interphases (EEIs) effectively enhance the stability of electrodes. Consequently, Li||Cu cells sustain up to 740 cycles with a high coulombic efficiency (CE) of 99%. Furthermore, 1.2 Ah Li||LiNi 0.9 Co 0.05 Mn 0.05 O 2 (NCM90) pouch cells are assembled to assess practical applicability, which exhibit impressive cycling stability with a high CE of 99.8%.

Lithium-ion batteries, particularly those employing lithium metal-based anodes, have garnered significant attention as energy storage systems due to their high energy density during charge-discharge cycles. However, the fundamental mechanisms underlying the microstructural evolution during cycling remain insufficiently understood. Here, we introduce a rechargeable Li-ion probe specifically designed for real-time transmission electron microscopy (TEM) analysis of electrode materials. The probe withstands electron beam irradiation and preserves its functionality under ambient conditions, enabling repeated in situ TEM measurements. By applying galvanostatic conditions, we employed this Li-ion probe to visualize (de)lithiation processes in both a lithiophilic LiAu3 electrode and a lithiophobic Ni electrode. Furthermore, this probe is not limited to specific electrode materials but can be adapted for a wide range of battery components, including cathodes, anodes, and current collectors, making it a versatile tool for advanced energy storage research. Our findings demonstrate that the Li-ion probe facilitates critical insights into the interplay between the electrode microstructure and electrochemical behavior, thereby paving the way for advanced battery characterization techniques. This innovation establishes a foundation for future research aimed at unraveling the dynamic behavior of lithium-based electrodes during prolonged cycling.

The growing demand for high-energy-density lithium-ion batteries, driven by electric vehicles and large-scale energy storage systems, has highlighted Ni-rich layered oxides as promising cathode materials due to their high capacity and cost advantages over cobalt-rich alternatives. However, their commercialization faces challenges from the synthesis process, where excess lithium is used to ensure phase purity and performance. This excess leads to the formation of residual lithium compounds like LiOH and Li₂CO₃, which cause slurry gelation, poor electrode processing, and side reactions with the electrolyte, resulting in gas generation, swelling, and reduced cycle life. Traditional washing methods used to remove these residual compounds complicate manufacturing by requiring additional drying steps, increasing energy consumption, and introducing contamination risks. Therefore, there is a strong need for alternative strategies that can effectively reduce residual lithium while simplifying the process and lowering costs, ultimately improving the practicality and scalability of Ni-rich cathode production. In this study, the residual lithium compounds on the Ni-rich cathode materials have been modified to a useful compound for improving the cycle stability instead of the removal by using in-situ and ex-situ adding process. By simplifying the process and reducing reliance on conventional washing, this approach aligns well with the industry's goal of developing high-performance, low-cost, and scalable cathode materials for next-generation lithium-ion batteries.

Compared to LiCoO2, a high Ni layered material has been spotlighted in terms of cost and capacity but suffers from poor electrochemical reversibility caused by a large volume change during the charge/discharge process. Here, we simultaneously change both bulk and surface properties by adding vanadium. Since the V addition is not incorporated into the bulk, it instead of Ni makes Ni deficiency in the bulk and then increases the oxidation state of Ni, resulting in a decrease in Li/Ni disordering and further activation of the H2/H3 phase transition. The V addition can be segregated to the surface leading to the formation of a Li-V-O related compound and the surface layer suppresses the side reactions leading to a gradual increase in a polarization and voltage shift of H2/ H3 phase transition (60 mV -> 6 mV) and the increase in the capacity retention for 150 cycles. Further increase in capacity retention without sacrificing the positive effects of the V addition can be achieved by lowering the heating temperature. The finding and understanding will stimulate research on improving the electrochemical properties of high Ni materials.

AbstractOut of practicality, ambient air rather than oxygen is preferred as a fuel in electrochemical systems, but CO2 and H2O present in air cause severe irreversible reactions, such as the formation of carbonates and hydroxides, which typically degrades performance. Herein, we report on a Na-air battery enabled by a reversible carbonate reaction (Na2CO3·xH2O, x = 0 or 1) in Nasicon solid electrolyte (Na3Zr2Si2PO12) that delivers a much higher discharge potential of 3.4 V than other metal-air batteries resulting in high energy density and achieves > 86 % energy efficiency at 0.1 mA cm−2 over 100 cycles. This cell design takes advantage of moisture in ambient air to form an in-situ catholyte via the deliquescent property of NaOH. As a result, not only reversible electrochemical reaction of Na2CO3·xH2O is activated but also its kinetics is facilitated. Our results demonstrate the reversible use of free ambient air as a fuel, enabled by the reversible electrochemical reaction of carbonates with a solid electrolyte.

For highly active electron transfer and ion diffusion, controlling the surface wettability of electrically and thermally conductive 3D graphene foams (3D GFs) is required. Here, we present ultrasimple and rapid superwettability switching of 3D GFs in a reversible and reproducible manner, mediated by solvent-exclusive microwave arcs. As the 3D GFs are prepared with vapors of nonpolar acetone or polar water exclusively, short microwave radiation (<= 10 s) leads to plasma hotspot-mediated production of methyl and hydroxyl radicals, respectively. Upon immediate radical chemisorption, the 3D surfaces become either superhydrophobic (water contact angle = similar to 170 degrees) or superhydrophilic (similar to 0 degrees), and interestingly, the wettability transition can be repeated many times due to the facile exchange between previously chemisorbed and newly introduced radicals via the formation of methanol-like intermediates. When 3D GFs of different surficial polarities are incorporated into electric double-layer capacitors with nonpolar ionic liquids or polar aqueous electrolytes, the polarity matching between graphene surfaces and electrolytes results in >= 548.0 times higher capacitance compared to its mismatching at >= 0.5 A g(-1), demonstrating the significance of wettability-controlled 3D GFs.

Despite the promising features of Li7La3Zr2O12 (LLZO) as a solid electrolyte (SE), its air handleability and compatibility with Li metal have been overlooked. This study reports on a Li2CO3-proof LLZO (AH-LLZO) SE that exhibits remarkable air handleability in humid environments for months and outstanding Li metal wettability even after long-time air exposure. The formation of the Li-Al-O compounds at both the surface and the grain boundary inside caused by excess Li and Al suppresses not only Li2CO3 formation at the surface but also its propagation because it improves the hydrophobic property of the surface and the grain boundary. Furthermore, AH-LLZO is handled/stored in ambient air and exhibits excellent Li metal wettability that enables an ultra-thin Li metal seeding layer to achieve high energy density. The cell that has similar to 3.43 mu m wetted Li metal with the lowest capacity ratio of negative to positive electrode (similar to 0.176) demonstrates outstanding electrochemical performance. This demonstration will suggest a new direction for advancing high-energy-density solid-state Li metal batteries.

Low-cost Fe can be used for forming cation-disordered rocksalt Li-excess (DRX) materials instead of high-cost d 0 -species and then the Fe-based DRX can be promising electrode materials because they can theoretically achieve high capacity, resulting from additional oxygen redox reaction and stable cation-disordered structure. However, Fe-based DRX materials suffer from large voltage hysteresis, low electrochemical activity, and poor cyclability, so it is highly challenging to utilize them as practical electrode materials for a cell. Here, novel high-capacity Li-Fe-Ti-Mo electrode materials (LFTMO) with high average discharge voltage and reasonable stability are reported. The effect of Ti/Mo on electrochemical reactions in Fe-based DRX materials (LFTMO) is studied by controlling its composition ratio and using techniques for analyzing the local environment to find the key factors that improve its activity. It is found out that the introduction of appropriate quantity of redox-active Mo 4+/5+ to Fe-based DRX materials can help stabilize the oxygen redox reaction via changing a local structure and can suppress a Fe redox reaction, which can cause poor performance. The understandings will help develop high capacity and long cyclability Fe-based DRX electrode materials.

A novel strategy for preventing battery thermal runaway has been proposed. A self-discharge reaction which spontaneously occurs above 100 °C can improve phase stability of the delithiated high Ni cathode via Li x S-induced lithiation.

Low-cost Fe can be used for forming cation-disordered rocksalt Li-excess (DRX) materials instead of high-cost d(0)-species and then the Fe-based DRX can be promising electrode materials because they can theoretically achieve high capacity, resulting from additional oxygen redox reaction and stable cation-disordered structure. However, Fe-based DRX materials suffer from large voltage hysteresis, low electrochemical activity, and poor cyclability, so it is highly challenging to utilize them as practical electrode materials for a cell. Here, novel high-capacity Li-Fe-Ti-Mo electrode materials (LFTMO) with high average discharge voltage and reasonable stability are reported. The effect of Ti/Mo on electrochemical reactions in Fe-based DRX materials (LFTMO) is studied by controlling its composition ratio and using techniques for analyzing the local environment to find the key factors that improve its activity. It is found out that the introduction of appropriate quantity of redox-active Mo4+/5+ to Fe-based DRX materials can help stabilize the oxygen redox reaction via changing a local structure and can suppress a Fe redox reaction, which can cause poor performance. The understandings will help develop high capacity and long cyclability Fe-based DRX electrode materials.