Long-Life Lithium-Metal All-Solid-State Batteries and Stable Li Plating Enabled by In Situ Formation of Li3 PS4 in the SEI Layer

Enhanced Regional Electric Potential Difference of Graphdiyne Through Asymmetric Substitution Strategy Boosts Li+ Migration in Composite Polymer Solid-State Electrolyte

Low ionic conductivity is a major obstacle for polymer solid-state electrolytes. In response to this issue, a design concept of enhanced regional electric potential difference (EREPD) is proposed to modulate the interaction of nanofillers with other components in the composite polymer solid-state electrolytes (CPSEs). While ensuring the periodic structure of the graphdiyne (GDY) backbone, methoxy-substituted GDY (OGDY) is prepared by an asymmetric substitution strategy, which increases the electric potential differences within each repeating unit of GDY. The staggered distributed electron-rich regions and electron-deficient regions on the two-dimensional plane of OGDY increase the free Li+ concentration through Lewis acid-base pair interaction. The adjacent ERRs and EDRs form uniformly distributed EREPDs, creating a continuous potential gradient that synergistically facilitates the efficient migration of Li+. Impressively, the OGDY/poly(ethylene oxide) (PEO) exhibits a high ionic conductivity (1.1 × 10-3 S cm-1) and ion mobility number (0.71). In addition, the accelerated Li+ migration promotes the formation of uniform and dense SEI layers and inhibits the growth of lithium dendrites. As a proof of concept, Li||Li symmetric cell and Li||LiFePO4 full cell and pouch cell assembled with OGDY/PEO exhibit good performance, highlighting the effectiveness of our EREPD design strategy for improving CPSEs performance.

Molecular Design of Polymeric Metal-Organic Nanocapsule Networks for Solid-State Lithium Batteries

Solid-state electrolytes (SSEs) have emerged as high-priority materials for ensuring the safe operation of solid-state lithium (Li) batteries. However, current SSEs still face challenges of balancing stability and ionic conductivity, which limits their practical applications in solid-state Li batteries. Here, we report a general strategy for achieving high-performance SSEs by constructing a Li+-conducted polymeric metal-organic nanocapsule (PolyMONC(Li)) network through molecular design. With the unique cage structure and pore size, metal-organic nanocapsule (MONC) can achieve excellent anion confinement effects. The PolyMONC(Li) network with continuous Li+ conduction pathways serves as a solid electrolyte exhibiting a high ionic conductivity (0.18 mS cm-1 at 25 °C) and a high Li+ transference number (0.83). Combining the two superiorities of optimal balance between mechanical strength and excellent Li+ conductivity, the PolyMONC(Li) can still restrain the dendrite growth and prevent Li symmetric batteries from short-circuiting even over 900 h cycling. The PolyMONC(Li)-based SSEs Li-metal batteries achieved a higher specific capacity than common polymer electrolytes such as polyethylene oxide-based SSE. Additionally, taking advantage of the PolyMONC(Li) electrode binder, the solid-state Li-O2 battery achieves a stable cycling over 400 cycles. This work provides a comprehensive guideline for developing porous solids from molecule design to practical application.

Electronic Localization Enables Long-Cycling Sulfides-Based All-Solid-State Lithium Batteries

Argyrodite-based sulfide electrolytes have received considerable attention in all-solid-state lithium metal batteries owing to their high ionic conductivity and good mechanical property. However, the reactivity between sulfide electrolytes and lithium anode leads to continuous interfacial reactions and dendrites growth, which severely hinders their practical applications. We propose an electron localization strategy by modulating the d-p orbital hybridization within the PS4 tetrahedral structure of Li6PS5Cl through homogeneous incorporation of yttrium (Y) and oxygen (O). The introduction of Y strengthens the Madelung energy with sulfur (S) atom and induces the electronic localization of S atom, which suppresses the interaction between lithium metal and S atom of the tetrahedron. The air-stability is also enhanced due to oxygen introduction. Furthermore, the in situ formation of Li2O interphase acts as a protective barrier, synergistically mitigating the interfacial reactions between lithium metal and Li6PS5Cl. The Li symmetric cell with the modulated Li6PS5Cl electrolyte achieves stable lithium plating/stripping for over 4800 h. The all-solid-state batteries with LiCoO2/Li-In electrode display a remarkable long cycle performance with 100% retention after 1300 cycles at 0.5 C. This study presents a distinct strategy that employs the electron localization driven by modulating orbital hybridization to achieve ultrastable interface in sulfide-based all-solid-state lithium batteries.

"Oxygen Into Sulfur"- New Synthesis of Sulfide Solid Electrolyte by Oxygenophilic Boron

Sulfide solid electrolytes (SEs) with high ionic conductivity and facile formability provide great promise to construct high energy density and safe all-solid-state batteries (ASSBs). However, the poor air stability of sulfide feedstock and SEs makes the synthesis, storage, and postprocessing of the materials in a dry inert-gas atmosphere, which increases the complexity and cost of the production process. Here, a boron-assisted sulfurization synthesis method is reported for preparing various sulfide SEs from oxide raw materials, including Li4SnS4, Na3SbS4, and Li6PS5X (X = Cl, Br). Boron bonds oxygen from oxide precursors and can be separated, while elemental sulfur reacts with the remaining mixture to form sulfide SEs. Furthermore, nontoxic boron and sulfur ensure the safety of production. Finally, the assembled lithium symmetric batteries and all-solid-state batteries with prepared sulfide SEs exhibit stable cycling. Hence, this work may be important for the practical production and application of sulfide-based ASSBs.

Revealing Local Diffusion Dynamics in Hybrid Solid Electrolytes

Hybrid solid electrolytes (HSEs) leverage the benefits of their organic and inorganic components, yet optimizing ion transport and component compatibility requires a deeper understanding of their intricate ion transport mechanisms. Here, macroscopic charge transport is correlated with local lithium (Li)-ion diffusivity in HSEs, using poly(ethylene oxide) (PEO) as matrix and Li6PS5Cl as filler. Solvent- and dry-processing methods were evaluated for their morphological impact on Li-ion transport. Through multiscale solid-state nuclear magnetic resonance analysis, we reveal that the filler enhances local Li-ion diffusivity within the slow polymer segmental dynamics. Phase transitions indicate inhibited crystallization in HSEs, with reduced Li-ion diffusion barriers attributed to enhanced segmental motion and conductive polymer conformations. Relaxometry measurements identify a mobile component unique to the hybrid system at low temperatures, indicating Li-ion transport along polymer-filler interfaces. Comparative analysis shows solvent-processed HSEs exhibit better morphological uniformity and enhanced compatibility with Li-metal anodes via an inorganic-rich solid electrolyte interphase.

Surface-Confined Disordered Hydrogen Bonds Enable Efficient Lithium Transport in All-Solid-State PEO-Based Lithium Battery

Polyethylene oxide (PEO)-based electrolytes are essential to advance all-solid-state lithium batteries (ASSLBs) with high safety/energy density due to their inherent flexibility and scalability. However, the inefficient Li+ transport in PEO often leads to poor rate performance and diminished stability of the ASSLBs. The regulation of intermolecular H-bonds is regarded as one of the most effective approaches to enable efficient Li+ transport, while the practical performances are hindered by the electrochemical instability of free H-bond donors and the constrained mobility of highly ordered H-bonding structures. To overcome these challenges, we develop a surface-confined disordered H-bond system with stable donor-acceptor interactions to construct a loosened chain segments/ions arrangement in the bulk phase of PEO-based electrolytes, realizing the crystallization inhibition of PEO, weak coordination of Li+ and entrapment of anions, which are conducive to efficient Li+ transport and stable Li+ deposition. The rationally designed LiFePO4-based ASSLB demonstrates a long cycle-life of over 400 cycles at 1.0 C and 65 °C with a capacity retention rate of 87.5 %, surpassing most of the currently reported polymer-based ASSLBs. This work highlights the importance of confined disordered H-bonds on Li+ transport in an all-solid-state battery system, paving the way for the future design of polymer-based ASSLBs.

Characterizing Electrode Materials and Interfaces in Solid-State Batteries

Solid-state batteries (SSBs) could offer improved energy density and safety, but the evolution and degradation of electrode materials and interfaces within SSBs are distinct from conventional batteries with liquid electrolytes and represent a barrier to performance improvement. Over the past decade, a variety of imaging, scattering, and spectroscopic characterization methods has been developed or used for characterizing the unique aspects of materials in SSBs. These characterization efforts have yielded new understanding of the behavior of lithium metal anodes, alloy anodes, composite cathodes, and the interfaces of these various electrode materials with solid-state electrolytes (SSEs). This review provides a comprehensive overview of the characterization methods and strategies applied to SSBs, and it presents the mechanistic understanding of SSB materials and interfaces that has been derived from these methods. This knowledge has been critical for advancing SSB technology and will continue to guide the engineering of materials and interfaces toward practical performance.

Catalysis of a LiF-rich SEI by aromatic structure modified porous polyamine for stable all-solid-state lithium metal batteries

Poly(ethylene oxide) (PEO)-based solid-state polymer electrolyte (SPE) is a promising candidate for the next generation of safer lithium-metal batteries. However, the serious side reaction between PEO and lithium metal and the uneven deposition of lithium ions lead to the growth of lithium dendrites and the rapid decline of battery cycle life. Building a LiF-rich solid electrolyte interface (SEI) layer is considered to be an effective means to solve the above problems. Here, porous organic polymers (POPs) with aromatic structures and non-aromatic structures were synthesized and introduced into the PEO-based SPE as fillers to explore the effect of aromatic structures on LiF-rich SEI formation. The results show that the POPs containing aromatic groups could catalyze the decomposition of LiTFSI to form a stable LiF-rich SEI layer and inhibit the growth of lithium dendrites. The discharge capacity of the LFP/Li battery is 103 mA h g-1 after 500 cycles at 1C (100 °C). It provides a promising way to improve the stability of the solid electrolyte matrix and SEI layer.

Highly stable silicon oxycarbide all-solid-state batteries enabled by machined learning accelerated screening of oxides and sulfides electrolytes

Traditional trial-error approach severely limits and restricts rapid development of high-performance anode and electrolytes materials, searching huge parameters space of various anode-solid electrolyte interfaces in an effective and efficient way is the key issue. Here, a novel computational strategy combining machine learning and first-principles is proposed to achieve efficient high-throughput screening of oxides and sulfides electrolytes for highly stable silicon oxycarbide all-solid-state batteries. First-principles calculations demonstrate significant compact of material type and elemental doping on interfacial compatibility between silicon oxycarbide and various electrolytes. By proposing several novel descriptors including interfacial adhesion and formation energies of frozen system with low computation cost, the amounts of demanded trainings data are significantly reduced. Gradient-boosted regression tree model shows low mean absolute errors of 0.09 and high R2 value of 0.99 for the prediction of interface formation energy, demonstrating ultrahigh accuracy and reliability of the algorithm. The present work discovers a series of uninvestigated stable anode-solid electrolytes interfacial couples for further experimental preparation.

Mechanism and Control Strategies of Lithium-Ion Battery Safety: A Review

Lithium-ion batteries (LIBs) are extensively used everywhere today due to their prominent advantages. However, the safety issues of LIBs such as fire and explosion have been a serious concern. It is important to focus on the root causes of safety accidents in LIBs and the mechanisms of their development. This will enable the reasonable control of battery risk factors and the minimization of the probability of safety accidents. Especially, the chemical crosstalk between two electrodes and the internal short circuit (ISC) generated by various triggers are the main reasons for the abnormal rise in temperature, which eventually leads to thermal runaway (TR) and safety accidents. Herein, this review paper concentrates on the advances of the mechanism of TR in two main paths: chemical crosstalk and ISC. It analyses the origin of each type of path, illustrates the evolution of TR, and then outlines the progress of safety control strategies in recent years. Moreover, the review offers a forward-looking perspective on the evolution of safety technologies. This work aims to enhance the battery community's comprehension of TR behavior in LIBs by categorizing and examining the pathways induced by TR. This work will contribute to the effective reduction of safety accidents of LIBs.

In Situ Welding Ionic Conductive Breakpoints for Highly Reversible All-Solid-State Lithium-Sulfur Batteries

Poly(ethylene oxide) (PEO)-based solid-state lithium-sulfur batteries (SSLSBs) have garnered considerable interest owing to their impressive energy density and high safety. However, the dissolved lithium polysulfide (LiPS) together with sluggish reaction kinetics disrupts the electrolyte network, bringing about ionic conductive breakpoints and severely limiting battery performance. To cure this, we propose an in situ welding strategy by introducing phosphorus pentasulfide (P2S5) as the welding filler into PEO-based solid cathodes. P2S5 can react with LiPS to form ion-conducting lithium polysulfidophosphate (LSPS), which suppresses the interaction with PEO and in situ weld breakpoints within the ionic conductive network. Of interest, LSPS also shows another function, that is, to catalyze sulfur redox reactions by decreasing the activation energy of sulfur reduction reaction from 0.87 to 0.75 eV, mitigating the shuttle effect. The in situ welding strategy helps the assembled SSLSB to feature exceptional cycling stability and a high energy density of up to 358 Wh·kg-1 due to the high sulfur utilization. Our findings pave an avenue for practical high-performance SSLSBs with a novel welding filler for in situ welding of ionic conductive network.

Interfacial Engineering Constructing TFSI- Ion-Sieve Protective Umbrella Guiding Li-Ion Selective Transport and Solid SEI Growth

A novel strategy is proposed by constructing TFSI- ion-sieve interlayer to guide Li-ion selective transport and solid SEI growth. The uniform MgF2 seeds on the fiber surface reacts rapidly with Li+ in electrolyte to form Mg and LiF dual functional sites for the first charging process. Benefiting from the high affinity of LiF, the TFSI- ions is enriched near the anode forming an ion-sieve interlayer, which acts as a protective umbrella and guides priority penetration of Li+ due to the coordination reaction with Li+ and thus homogenize the Li+ flux. While the Mg sites induce Li nucleation with its strong lithiophilicity and facilitate uniform Li plating on fiber surface. Furthermore, as raw material of LiF, the TFSI- enrichment on anode surface is contribute to increasing LiF content in SEI, achieving the stability enhancement and densification of SEI. Of greater importance, the excess Li+ can spread to the adjacent Mg sites for nucleation by means of ultralow Li+ migration barrier on LiF and Mg. The combination of the ion-sieve homogenization of Li+ flux in electrolyte and the uniformity of Li+ transport in LiF/Mg solid medium achieves the purpose of uniform Li metal plating/stripping.

Electronic-ionic bi-functional conduction β-Li3PS4-coated graphene hollow spheres as a highly stable lithium metal anode skeleton

Although Li metal is considered the most potential anode for Li based batteries, the repeatedly large volume variation and low Coulombic efficiency (CE) are still serious challenges for commercial application. Herein, the interconnect closed hollow graphene spheres with electronic-ionic bi-functional conduction network containing Li4.4Sn nanoparticles loaded internally and β-Li3PS4 solid electrolyte layer coated externally (β-LPS/SG/Li4.4Sn) is proposed to achieve uniform and dense Li deposition. Density functional theory (DFT) calculation and experimental results show that Li4.4Sn owns larger Li binding energy and lower nucleation overpotential than spherical graphene (SG), thus being able to guide Li traversing and depositing inside the hollow spheres. The Tafel curves, Li+ diffusion activation energy and experimental results reveal that the β-Li3PS4 coating layer significantly improves the ionic conductivity of the negative skeleton, covers the defect sites on the SG surface, provides continuous ion transmission channels and accelerates Li+ migration rate. The synergy of both can inhibit the formation of dendritic Li and reduce side reaction between freshly deposited lithium and the organic electrolyte. It's found that Li is preferentially deposited within the SG, evenly deposited on the spherical shell surface until it's completely filled to obtain a dense lithium layer without tip effect. As a result, the β-LPS/SG/Li4.4Sn anode exhibits a long life of up to 2800 h, an extremely low overpotential (∼13 mV) and a high CE of 99.8 % after 470 cycles. The LiFePO4-based full cell runs stably with a high capacity retention of 86.93 % after 800 cycles at 1C. It is considered that the novel structure design of Li anode skeleton with electron-ionic bi-functional conduction is a promising direction to construct long-term stable lithium metal anodes.

Preparation of a lithium-sulfur battery diaphragm catalyst and its battery performance

Lithium-sulfur batteries (LSBs) with metal lithium as the anode and elemental sulfur as the cathode active materials have attracted extensive attention due to their high theoretical specific capacity (1675 mA h g-1), high theoretical energy density (2600 W h kg-1), low cost, and environmental friendliness. However, the discharge intermediate lithium polysulfide undergoes a shuttle side reaction between the two electrodes, resulting in low utilization of the active substances. This limits the capacity and cycle life of LSBs and further delays their commercial development. However, the number of active sites and electron transport capacity of such catalysts still do not meet the practical development needs of lithium-sulfur batteries. In view of these issues, this paper focuses on a zinc-cobalt compound catalyst, modifying it through heteroatom doping, bimetallic synergistic effect and heterogeneous structure design to enhance the performance of LSBs as a separator modification material. A carbon shell-supported boron-doped ZnS/CoS2 heterojunction catalytic material (B-ZnS/CoS2@CS) was prepared, and its performance in lithium-sulfur batteries was evaluated. A carbon substrate (CS) was prepared by pyrolysis of sodium citrate, and the boron-doped ZnS/CoS2 heterojunction catalyst was formed on the CS using a one-step solvothermal method. The unique heterogeneous interface provides numerous active sites for the adsorption and catalysis of polysulfides. The uniformly doped, electron-deficient boron further enhances the Lewis acidity of the ZnS/CoS2 heterojunction, while also regulating electron transport. The B-ZnS/CoS2@CS catalyst effectively inhibits the diffusion of LiPS anions by utilizing additional lone-pair electrons. The lithium-sulfur battery using the catalyst-modified separator achieves a high specific capacity of 1241 mA h g-1 at a current density of 0.2C and retains a specific capacity of 384.2 mA h g-1 at 6.0C. In summary, B-ZnS/CoS2@CS heterojunction catalysts were prepared through boron doping modification. They can promote the conversion of polysulfides and effectively inhibit the shuttle effect. The findings provide valuable insights for the future modification and preparation of lithium-sulfur battery catalysts.

Highly Conductive and Stable Composite Polymer Electrolyte with Boron Nitride Nanotubes for All-Solid-State Lithium Metal Batteries

All-solid-state lithium metal batteries (ASSLMBs) have emerged as the most promising next-generation energy storage devices. However, the unsatisfactory ionic conductivity of solid electrolytes at room temperature has impeded the advancement of solid-state batteries. In this work, a multifunctional composite solid electrolyte (CSE) is developed by incorporating boron nitride nanotubes (BNNTs) into polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). BNNTs, with a high aspect ratio, trigger the dissociation of Li salts, thus generating a greater population of mobile Li+, and establishing long-distance Li+ transport pathways. PVDF-HFP/BNNT exhibits a high ionic conductivity of 8.0 × 10-4 S cm-1 at room temperature and a Li+ transference number of 0.60. Moreover, a Li//Li symmetric cell based on PVDF-HFP/BNNT demonstrates robust cyclic performance for 3400 h at a current density of 0.2 mA cm-2. The ASSLMB formed from the assembly of PVDF-HFP/BNNT with LiFePO4 and Li exhibits a capacity retention of 93.2% after 850 cycles at 0.5C and 25 °C. The high-voltage all-solid-state LiCoO2/Li cell based on PVDF-HFP/BNNT also exhibits excellent cyclic performance, maintaining a capacity retention of 96.4% after 400 cycles at 1C and 25 °C. Furthermore, the introduction of BNNTs is shown to enhance the thermal conductivity and flame retardancy of the CSE.

Customized Li+ Solvation Sheath at the Poly(ethylene oxide)-Based Electrolyte/Ultrahigh-Nickel Cathode Interface toward Room-Temperature Solid-State Lithium Batteries

The matching of poly(ethylene oxide) (PEO)-based electrolytes with ultrahigh-nickel cathode materials is crucial for designing new-generation high-energy-density solid-state lithium metal batteries (SLMBs), but it is limited by serious interfacial side reactions between PEO and ultrahigh-nickel materials. Here, a high-concentration electrolyte (HCE) interface with a customized Li+ solvation sheath is constructed between the cathode and the electrolyte. It induces the formation of an anion-regulated robust cathode/electrolyte interface (CEI), reduces the unstable free-state solvent, and finally achieves the compatibility of PEO-based electrolytes with ultrahigh-nickel cathode materials. Meanwhile, the corrosion of the Al current collector caused by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) ions is prevented by lithium difluoro(oxalato)borate (LiDFOB) ions. The synergistic effect of the double lithium salt is achieved by a well-tailored ratio of TFSI- and DFOB- in the first solvation sheath of Li+. Compared with reported PEO-based SLMBs matched with ultrahigh-nickel (Ni ≥ 90%) cathodes, the SLMB in this work delivers a high discharge specific capacity of 216.4 mAh g-1 (0.1C) even at room temperature. This work points out a direction to optimize the cathode/electrolyte interface.

Small Additives Make Big Differences: A Review on Advanced Additives for High-Performance Solid-State Li Metal Batteries

Solid-state lithium (Li) metal batteries, represent a significant advancement in energy storage technology, offering higher energy densities and enhanced safety over traditional Li-ion batteries. However, solid-state electrolytes (SSEs) face critical challenges such as lower ionic conductivity, poor stability at the electrode-electrolyte interface, and dendrite formation, potentially leading to short circuits and battery failure. The introduction of additives into SSEs has emerged as a transformative approach to address these challenges. A small amount of additives, encompassing a range from inorganic and organic materials to nanostructures, effectively improve ionic conductivity, drawing it nearer to that of their liquid counterparts, and strengthen mechanical properties to prevent cracking of SSEs and maintain stable interfaces. Importantly, they also play a critical role in inhibiting the growth of dendritic Li, thereby enhancing the safety and extending the lifespan of the batteries. In this review, the wide variety of additives that have been investigated, is comprehensively explored, emphasizing how they can be effectively incorporated into SSEs. By dissecting the operational mechanisms of these additives, the review hopes to provide valuable insights that can help researchers in developing more effective SSEs, leading to the creation of more efficient and reliable solid-state Li metal batteries.

Ultrafast-Loaded Nickel Sulfide on Vertical Graphene Enabled by Joule Heating for Enhanced Lithium Metal Batteries

The design and fabrication of a lithiophilic skeleton are highly important for constructing advanced Li metal anodes. In this work, a new lithiophilic skeleton is reported by planting metal sulfides (e.g., Ni3S2) on vertical graphene (VG) via a facile ultrafast Joule heating (UJH) method, which facilitates the homogeneous distribution of lithiophilic sites on carbon cloth (CC) supported VG substrate with firm bonding. Ni3S2 nanoparticles are homogeneously anchored on the optimized skeleton as CC/VG@Ni3S2, which ensures high conductivity and uniform deposition of Li metal with non-dendrites. By means of systematic electrochemical characterizations, the symmetric cells coupled with CC/VG@Ni3S2 deliver a steady long-term cycle within 14 mV overpotential for 1800 h (900 cycles) at 1 mA cm-2 and 1 mAh cm-2. Meanwhile, the designed CC/VG@Ni3S2-Li||LFP full cell shows notable electrochemical performance with a capacity retention of 92.44% at 0.5 C after 500 cycles and exceptional rate performance. This novel synthesis strategy for metal sulfides on hierarchical carbon-based materials sheds new light on the development of high-performance lithium metal batteries (LMBs).

Dendrite-Free All-Solid-State Lithium Metal Batteries by In Situ Phase Transformation of the Soft Carbon-Li3N Interface Layer

The accelerated formation of lithium dendrites has considerably impeded the advancement and practical deployment of all-solid-state lithium metal batteries (ASSLMBs). In this study, a soft carbon (SC)-Li3N interface layer was developed with both ionic and electronic conductivity, for which the in situ lithiation reaction not only lithiated SC into LiC6 with good electronic/ionic conductivity but also successfully transformed the mixed-phase Li3N into pure-phase β-Li3N with a high ionic conductivity/ion diffusion coefficient and stability to lithium metal. The mixed conductive interface layer facilitates fast Li+ transport at the interface and induces the homogeneous deposition of lithium metal inside it. This effectively inhibits the formation of lithium dendrites and greatly improves the performance of the ASSLMB. The ASSLMB assembled with the SC-Li3N interface layer exhibits high areal capacity (15 mA h cm-2), high current density (7.5 mA cm-2), and long cycle life (6000 cycles). These results indicate that this interface layer has great potential for practical applications in high-energy-density ASSLMBs.

Stable Oxyhalide-Nitride Fast Ionic Conductors for All-Solid-State Li Metal Batteries

Rechargeable all-solid-state lithium metal batteries (ASSLMBs) utilizing inorganic solid-state electrolytes (SSEs) are promising for electric vehicles and large-scale grid energy storage. However, the Li dendrite growth in SSEs still constrains the practical utility of ASSLMBs. To achieve a high dendrite-suppression capability, SSEs must be chemically stable with Li, possess fast Li transfer kinetics, and exhibit high interface energy. Herein, a class of low-cost, eco-friendly, and sustainable oxyhalide-nitride solid electrolytes (ONSEs), denoted as LixNyIz-qLiOH (where x = 3y + z, 0 ≤ q ≤ 0.75), is designed to fulfill all the requirements. As-prepared ONSEs demonstrate chemically stable against Li and high interface energy (>43.08 meV Å-2), effectively restraining Li dendrite growth and the self-degradation at electrode interfaces. Furthermore, improved thermodynamic oxidation stability of ONSEs (>3 V vs Li+/Li, 0.45 V for pure Li3N), arising from the increased ionicity of Li─N bonds, contributes to the stability in ASSLMBs. As a proof-of-concept, the optimized ONSEs possess high ionic conductivity of 0.52 mS cm-1 and achieve long-term cycling of Li||Li symmetric cell for over 500 h. When coupled with the Li3InCl6 SSE for high-voltage cathodes, the bilayer oxyhalide-nitride/Li3InCl6 electrolyte imparts 90% capacity retention over 500 cycles for Li||1 mAh cm-2 LiCoO2 cells.

Indium Nitride Nanowires: Low Redox Potential Anodes for Lithium-Ion Batteries

Advanced lithium-ion batteries (LIBs) are crucial to portable devices and electric vehicles. However, it is still challenging to further develop the current anodic materials such as graphite due to the intrinsic limited capacity and sluggish Li-ion diffusion. Indium nitride (InN), which is a new type of anodic material with low redox potential (<0.7 V vs Li/Li+) and narrow bandgap (0.69 eV), may serve as a new high-energy density anode material for LIBs. Here, the growth of 1D single crystalline InN nanowires is reported on Au-decorated carbon fibers (InN/Au-CFs) via chemical vapor deposition, possessing a high aspect ratio of 400. The binder-free Au-CFs with high conductivity can provide abundant sites and enhance binding force for the dense growth of InN nanowires, displaying shortened Li ion diffusion paths, high structural stability, and fast Li+ kinetics. The InN/Au-CFs can offer stable and high-rate Li delithiation/lithiation without Li deposition, and achieve a remarkable capacity of 632.5 mAh g-1 at 0.1 A g-1 after 450 cycles and 416 mAh g-1 at a high rate of 30 A g-1. The InN nanowires as battery anodes shall hold substantial promise for fulfilling superior long-term cycling performance and high-rate capability for advanced LIBs.

12.6 μm-Thick Asymmetric Composite Electrolyte with Superior Interfacial Stability for Solid-State Lithium-Metal Batteries

Solid-state lithium metal batteries (SSLMBs) show great promise in terms of high-energy-density and high-safety performance. However, there is an urgent need to address the compatibility of electrolytes with high-voltage cathodes/Li anodes, and to minimize the electrolyte thickness to achieve high-energy-density of SSLMBs. Herein, we develop an ultrathin (12.6 µm) asymmetric composite solid-state electrolyte with ultralight areal density (1.69 mg cm-2) for SSLMBs. The electrolyte combining a garnet (LLZO) layer and a metal organic framework (MOF) layer, which are fabricated on both sides of the polyethylene (PE) separator separately by tape casting. The PE separator endows the electrolyte with flexibility and excellent mechanical properties. The LLZO layer on the cathode side ensures high chemical stability at high voltage. The MOF layer on the anode side achieves a stable electric field and uniform Li flux, thus promoting uniform Li+ deposition. Thanks to the well-designed structure, the Li symmetric battery exhibits an ultralong cycle life (5000 h), and high-voltage SSLMBs achieve stable cycle performance. The assembled pouch cells provided a gravimetric/volume energy density of 344.0 Wh kg-1/773.1 Wh L-1. This simple operation allows for large-scale preparation, and the design concept of ultrathin asymmetric structure also reveals the future development direction of SSLMBs.

In Situ Construction of LiF-Li3N-Rich Interface Contributed to Fast Ion Diffusion in All-Solid-State Lithium-Sulfur Batteries

All-solid-state lithium-sulfur batteries (ASSLSBs) have attracted wide attention due to their ultrahigh theoretical energy density and the ability of completely avoiding the shuttle effect. However, the further development of ASSLSBs is limited by the poor kinetic properties of the solid electrode interface. It remains a great challenge to achieve good kinetic properties, by common strategies to substitute sulfur-transition metal and organosulfur composites for sulfur without reducing the specific capacity of ASSLSBs. In this study, a sulfur-(Ketjen Black)-(bistrifluoromethanesulfonimide lithium salt) (S-KB-LiTFSI) composite is constructed by introducing LiTFSI into the S-KB composite. The initial discharge capacity reaches up to 1483 mA h g-1, benefited from the improved ionic conductivity and diffusion kinetics of the S-KB-LiTFSI composite, where numerous LiF interphases with a Li3N component are in situ formed during cycling. Combined with DFT calculations, it is found that the migration barriers of LiF and Li3N are much smaller than that of the Li6PS5Cl solid electrolyte. The fast ionic conductors of LiF and Li3N not only enhance the Li+ transfer efficiency but also improve the interfacial stability. Therefore, the assembled ASSLSBs operate stably for 600 cycles at 200 mA g-1, and this study provides an effective strategy for the further development of ASSLSBs.

Design advanced lithium metal anode materials in high energy density lithium batteries

Nowadays, the ongoing electrical vehicles and energy storage devices give a great demand of high-energy-density lithium battery. The commercial graphite anode has been reached the limit of the theoretical capacity. Herein, we introduce lithium metal anode to demonstrate the promising anode which can replace graphite. Lithium metal has a high theoretical capacity and the lowest electrochemical potential. Hence, using lithium metal as the anode material of lithium batteries can reach the limit of energy and power density of lithium batteries. However, lithium metal has huge flaw such as unstable SEI layer, volume change and dendrites formation. Therefore, we give a review of the lithium metal anode on its issues and introduce the existing research to overcome these. Besides, we give the perspective that the engineering problems also restrict the commercial use of lithium metal. This review provides the reasonable method to enhance the lithium metal performance and give the development direction for the subsequent research.

Self-assembled hydrated copper coordination compounds as ionic conductors for room temperature solid-state batteries

As the core component of solid-state batteries, neither current inorganic solid-state electrolytes nor solid polymer electrolytes can simultaneously possess satisfactory ionic conductivity, electrode compatibility and processability. By incorporating efficient Li+ diffusion channels found in inorganic solid-state electrolytes and polar functional groups present in solid polymer electrolytes, it is conceivable to design inorganic-organic hybrid solid-state electrolytes to achieve true fusion and synergy in performance. Herein, we demonstrate that traditional metal coordination compounds can serve as exceptional Li+ ion conductors at room temperature through rational structural design. Specifically, we synthesize copper maleate hydrate nanoflakes via bottom-up self-assembly featuring highly-ordered 1D channels that are interconnected by Cu2+/Cu+ nodes and maleic acid ligands, alongside rich COO- groups and structural water within the channels. Benefiting from the combination of ion-hopping and coupling-dissociation mechanisms, Li+ ions can preferably transport through these channels rapidly. Thus, the Li+-implanted copper maleate hydrate solid-state electrolytes shows remarkable ionic conductivity (1.17 × 10-4 S cm-1 at room temperature), high Li+ transference number (0.77), and a 4.7 V-wide operating window. More impressively, Li+-implanted copper maleate hydrate solid-state electrolytes are demonstrated to have exceptional compatibility with both cathode and Li anode, enabling long-term stability of more than 800 cycles. This work brings new insight on exploring superior room-temperature ionic conductors based on metal coordination compounds.

Soft Carbon-Thiourea with Fast Bulk Diffusion Kinetics for Solid-State Lithium Metal Batteries

The development of all-solid-state lithium-metal batteries (ASSLMBs) is impeded by low coulomb efficiency, short lifetime, poor rate performance, and other problems caused by the rapid growth of lithium (Li) dendrites. Herein, a multiple-diffusion-channel N,S-doped soft carbon with expanded layer spacing is designed/developed by thiourea calcination for dendrite-free anodes. Since the enlarged layer spacing can improve Li+ transportation rate within the layers and N,S-doping can facilitate Li+ transport between the layers, the bulk phase diffusion (not just surface diffusion) kinetics can be improved, which in turn reduces the local current density, inhibits the growth of Li dendrites, and improves the rate performance. The resulting ASSLMB achieves record-high current density (15 mA cm-2 ), areal capacity (20 mAh cm-2 ), energy density (403 Wh kg-1 ), and ultra-long cycle life (13 000 cycles). >305 Wh kg-1 pouch cells are realized, representing one of the most critical breakthroughs for real-world application of ASSLMBs.

Highly Efficient Aligned Ion-Conducting Network and Interface Chemistries for Depolarized All-Solid-State Lithium Metal Batteries

Improving the long-term cycling stability and energy density of all-solid-state lithium (Li)-metal batteries (ASSLMBs) at room temperature is a severe challenge because of the notorious solid-solid interfacial contact loss and sluggish ion transport. Solid electrolytes are generally studied as two-dimensional (2D) structures with planar interfaces, showing limited interfacial contact and further resulting in unstable Li/electrolyte and cathode/electrolyte interfaces. Herein, three-dimensional (3D) architecturally designed composite solid electrolytes are developed with independently controlled structural factors using 3D printing processing and post-curing treatment. Multiple-type electrolyte films with vertical-aligned micro-pillar (p-3DSE) and spiral (s-3DSE) structures are rationally designed and developed, which can be employed for both Li metal anode and cathode in terms of accelerating the Li+ transport within electrodes and reinforcing the interfacial adhesion. The printed p-3DSE delivers robust long-term cycle life of up to 2600 cycles and a high critical current density of 1.92 mA cm-2. The optimized electrolyte structure could lead to ASSLMBs with a superior full-cell areal capacity of 2.75 mAh cm-2 (LFP) and 3.92 mAh cm-2 (NCM811). This unique design provides enhancements for both anode and cathode electrodes, thereby alleviating interfacial degradation induced by dendrite growth and contact loss. The approach in this study opens a new design strategy for advanced composite solid polymer electrolytes in ASSLMBs operating under high rates/capacities and room temperature.

A Dynamically Stable Mixed Conducting Interphase for All-Solid-State Lithium Metal Batteries

All-solid-state lithium (Li) metal batteries (ASSLMBs) employing sulfide solid electrolytes have attracted increasing attention owing to superior safety and high energy density. However, the instability of sulfide electrolytes against Li metal induces the formation of two types of incompetent interphases, solid electrolyte interphase (SEI) and mixed conducting interphase (MCI), which significantly blocks rapid Li-ion transport and induces uneven Li deposition and continuous interface degradation. In this contribution, a dynamically stable mixed conducting interphase (S-MCI) is proposed by in situ stress self-limiting reaction to achieve the compatibility of Li metal with composite sulfide electrolytes (Li6 PS5 Cl (LPSCl) and Li10 GeP2 S12 (LGPS)). The rational design of composite electrolytes utilizes the expansion stress induced by the electrolyte decomposition to in turn constrain the further decomposition of LGPS. Consequently, the S-MCI inherits the high dynamical stability of LPSCl-derived SEI and the lithiophilic affinity of Li-Ge alloy in LGPS-derived MCI. The Li||Li symmetric cells with the protection of S-MCI can operate stably for 1500 h at 0.5 mA cm-2 and 0.5 mAh cm-2 . The Li||NCM622 full cells present stable cycling for 100 cycles at 0.1 C with a high-capacity retention of 93.7%. This work sheds fresh insight into constructing electrochemically stable interphase for high-performance ASSLMBs.

Dielectric Filler-Induced Hybrid Interphase Enabling Robust Solid-State Li Metal Batteries at High Areal Capacity

The fillers in composite solid-state electrolyte are mainly responsible for the enhancement of the conduction of Li ions but barely regulate the formation of solid electrolyte interphase (SEI). Herein, a unique filler of dielectric NaNbO3 for the poly(vinylidene fluoride) (PVDF)-based polymer electrolyte, which is subjected to the exchange of Li+ and Na+ during cycling, is reported and the substituted Na+ is engaged in the construction of a fluorinated Li/Na hybrid SEI with high Young's modulus, facilitating the fast transport of Li+ at the interface at a high areal capacity and suppressing the Li dendrite growth. The dielectric NaNbO3 also induces the generation of high-dielectric β phase of PVDF to promote the dissociation of Li salt. The Li/Li symmetrical cell exhibits a long-term dendrite-free cycling over 600 h at a high areal capacity of 3 mA h cm-2 . The LiNi0.8 Mn0.1 Co0.1 O2 /Li solid-state cells with NaNbO3 stably cycle 2200 times at 2 C and that paired with high-loading cathode (10 mg cm-2 ) can stably cycle for 150 times and exhibit excellent performances at -20 °C. This work provides a novel design principle of fillers undertaking interfacial engineering in composite solid-state electrolytes for developing the safe and stable solid-state lithium metal battery.

Catalytic Tunable Black Phosphorus/Ceria Nanozyme: A Versatile Oxidation Cycle Accelerator for Alleviating Cisplatin-Induced Acute Kidney Injury

Oxidative stress is one leading inner cause of acute kidney injury (AKI) induced by cisplatin (DDP). Therefore, inhibiting oxidative stress is an important strategy to prevent the occurrence of DDP-induced AKI. Herein, a pH-selective "oxidative cycle accelerator" based on black phosphorus/ceria catalytic tunable nanozymes (BP@CeO2 -PEG) to effectively and persistently scavenge ROS for alleviating DDP-induced AKI is demonstrated. The BP@CeO2 -PEG nanozymes show pH-dependent multi-enzymatic activities, which are beneficial for selectively scavenging the excess ROS in renal tissues. In the neutral environment of kidneys, BP@CeO2 -PEG nanozymes can accelerate its catalytic "oxidative cycle" by increasing the ratio of Ce3+ /Ce4+ and improving the regeneration of ATP, effectively removing DDP-induced ROS. In addition, BP@CeO2 -PEG nanozymes can suppress the oxidative stress-triggered renal tubular epithelial cell apoptosis by inhibiting the PI3K/Akt signaling pathway. However, in the acidic environment of cancers, the presence of H+ inhibits the conversion of Ce4+ to Ce3+ , which in turn disrupts the oxidative cycle, resulting in the loss of ROS scavenging ability and ensuring the antitumor effect of DDP. Conclusively, the nanozymes offer an excellent antioxidant for alleviating cisplatin-induced AKI and extensive use in other ROS-based injuries.

Ion-Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries

Owing to high ionic conductivity and mechanical strength, poly(vinylidene fluoride) (PVDF) electrolytes have attracted increasing attention for solid-state lithium batteries, but highly reactive residual solvents severely plague cycling stability. Herein, we report a free-solvent-capturing strategy triggered by reinforced ion-dipole interactions between Li+ and residual solvent molecules. Lithium difluoro(oxalato)borate (LiDFOB) salt additive with electron-withdrawing capability serves as a redistributor of the Li+ electropositive state, which offers more binding sites for residual solvents. Benefiting from the modified coordination environment, the kinetically stable anion-derived interphases are preferentially formed, effectively mitigating the interfacial side reactions between the electrodes and electrolytes. As a result, the assembled solid-state battery shows a lifetime of over 2000 cycles with an average Coulombic efficiency of 99.9% and capacity retention of 80%. Our discovery sheds fresh light on the targeted regulation of the reactive residual solvent to extend the cycle life of solid-state batteries.

Experimental Corroboration of Lithium Orthothioborate Superionic Conductor by Systematic Elemental Manipulation

The Li superionic conductor Li3BS3 has been theoretically predicted as an ideal solid electrolyte (SE) due to its low Li+ migration energy barrier and high ionic conductivity. However, the experimentally synthesized Li3BS3 has a 104 times lower ionic conductivity. Herein, we investigate the effect of a series of cation and anion substitutions in Li3BS3 SE on its ionic conductivity, including Li3-xM0.05BS3 (M = Cu, Zn, Sn, P, W, x = 0.05, 0.1, 0.2, 0.25), Li3-yBS2.95X0.05 (X = O, Cl, Br, I, y = 0.05, 0.1) and Li2.75-xP0.05BS3-xClx (x = 0.05, 0.1, 0.15, 0.2, 0.4, 0.6). Amorphous ionic conductor Li2.55P0.05BS2.8Cl0.2 has a high ion conductivity of 0.52 mS cm-1 at room temperature with an activation energy of 0.41 eV. The electrochemical performance of all-solid-state batteries with Li2.55P0.05BS2.8Cl0.2 SEs show stable cycling with a discharge capacity retention of >97% after 200 cycles at 1C under 55 °C.

Toward robust solid-state lithium metal batteries by stabilizing a polyethylene oxide-based solid electrolyte interface with a biomass polymer filler

Achieving all-solid-state lithium-based batteries with high energy densities requires lightweight and ultrathin solid-state electrolytes (SSEs) with high Li+ conductivity, but this still poses significant challenges. Herein, we designed a robust and mechanically flexible SSE (denoted BC-PEO/LiTFSI) by using an environmentally friendly and low-cost approach that involves bacterial cellulose (BC) as a three-dimensional (3D) rigid backbone. In this design, BC-PEO/LiTFSI is tightly integrated and polymerized through intermolecular hydrogen bonding, and the rich oxygen-containing functional groups from the BC filler also provide the active site for Li+ hopping transport. Therefore, the all-solid-state Li-Li symmetric cell with BC-PEO/LiTFSI (containing 3% BC) showed excellent electrochemical cycling properties over 1000 h at a current density of 0.5 mA cm-2. Furthermore, the Li-LiFePO4 full cell showed steady cycling performance under 3 mg cm-2 areal loading at a current of 0.1 C, and the resultant Li-S full cell maintained over 610 mAh g-1 for upward of 300 cycles at 0.2 C and 60 °C.

One Stone, Three Birds: An Air and Interface Stable Argyrodite Solid Electrolyte with Multifunctional Nanoshells

Li6 PS5 Cl (LPSC) solid electrolytes, based on Argyrodite, have shown potential for developing high energy density and safe all-solid-state lithium metal batteries. However, challenges such as interfacial reactions, uneven Li deposition, and air instability remain unresolved. To address these issues, a simple and effective approach is proposed to design and prepare a solid electrolyte with unique structural features: Li6 PS4 Cl0.75 -OF0.25 (LPSC-OF0.25 ) with protective LiF@Li2 O nanoshells and F and O-rich internal units. The LPSC-OF0.25 electrolyte exhibits high ionic conductivity and the capability of "killing three birds with one stone" by improving the moist air tolerance, as well as the interface compatibility between the anode or cathode and the solid electrolyte. The improved performance is attributed to the peculiar morphology and the self-generating and self-healing interface coupling capability. When coupled with bare LiCoO2 , the LPSC-OF0.25 electrolyte enables stable operation under high cutoff voltage (≈4.65 V vs Li/Li+ ), thick cathodes (25 mg cm-2 ), and large current density (800 cycles at 2 mA cm-2 ). This rationally designed solid electrolyte offers promising prospects for solid-state batteries with high energy and power density for future long-range electric vehicles and aircrafts.

Engineering the Structural Uniformity of Gel Polymer Electrolytes via Pattern-Guided Alignment for Durable, Safe Solid-State Lithium Metal Batteries

Ultrathin and super-toughness gel polymer electrolytes (GPEs) are the key enabling technology for durable, safe, and high-energy density solid-state lithium metal batteries (SSLMBs) but extremely challenging. However, GPEs with limited uniformity and continuity exhibit an uneven Li+ flux distribution, leading to nonuniform deposition. Herein, a fiber patterning strategy for developing and engineering ultrathin (16 µm) fibrous GPEs with high ionic conductivity (≈0.4 mS cm-1 ) and superior mechanical toughness (≈613%) for durable and safe SSLMBs is proposed. The special patterned structure provides fast Li+ transport channels and tailoring solvation structure of traditional LiPF6 -based carbonate electrolyte, enabling rapid ionic transfer kinetics and uniform Li+ flux, and boosting stability against Li anodes, thus realizing ultralong Li plating/stripping in the symmetrical cell over 3000 h at 1.0 mA cm-2 , 1.0 mAh cm-2 . Moreover, the SSLMBs with high LiFePO4 loading of 10.58 mg cm-2 deliver ultralong stable cycling life over 1570 cycles at 1.0 C with 92.5% capacity retention and excellent rate capacity of 129.8 mAh g-1 at 5.0 C with a cut-off voltage of 4.2 V (100% depth-of-discharge). Patterned GPEs systems are powerful strategies for producing durable and safe SSLMBs.

Ion modulation engineering toward stable lithium metal anodes

Homogeneous ion transport during Li+ plating/stripping plays a significant role in the stability of Li metal anodes (LMAs) and the electrochemical performance of Li metal batteries (LMBs). Controlled ion transport with uniform Li+ distribution is expected to suppress notorious Li dendrite growth while stabilizing the susceptible solid electrolyte interfacial (SEI) film and optimizing the electrochemical stability. Here, we are committed to rendering a comprehensive study of Li+ transport during the Li plating/stripping process related to the interactions between the Li dendrites and SEI film. Moreover, rational ion modulation strategies based on functional separators, artificial SEI films, solid-state electrolytes and structured anodes are introduced to homogenize Li+ flux and stabilize the lithium metal surface. Finally, the current issues and potential opportunities for ion transport regulation to boost the high energy density of LMBs are described.

Supramolecular Polymer Ion Conductor with Weakened Li Ion Solvation Enables Room Temperature All-Solid-State Lithium Metal Batteries

Improved durability, enhanced interfacial stability, and room temperature applicability are desirable properties for all-solid-state lithium metal batteries (ASSLMBs), yet these desired properties are rarely achieved simultaneously. Here, in this work, it is noticed that the huge resistance at Li metal/electrolyte interface dominantly impeded the normal cycling of ASSLMBs especially at around room temperature (<30 °C). Accordingly, a supramolecular polymer ion conductor (SPC) with "weak solvation" of Li+ was prepared. Benefiting from the halogen-bonding interaction between the electron-deficient iodine atom (on 1,4-diiodotetrafluorobenzene) and electron-rich oxygen atoms (on ethylene oxide), the O-Li+ coordination was significantly weakened. Therefore, the SPC achieves rapid Li+ transport with high Li+ transference number, and importantly, derives a unique Li2 O-rich SEI with low interfacial resistance on lithium metal surface, therefore enabling stable cycling of ASSLMBs even down to 10 °C. This work is a new exploration of halogen-bonding chemistry in solid polymer electrolyte and highlights the importance of "weak solvation" of Li+ in the solid-state electrolyte for room temperature ASSLMBs.

Functional Separator Enabled by Covalent Organic Frameworks for High-Performance Li Metal Batteries

Uncontrolled ion transport and susceptible SEI films are the key factors that induce lithium dendrite growth, which hinders the development of lithium metal batteries (LMBs). Herein, a TpPa-2SO₃ H covalent organic framework (COF) nanosheet adhered cellulose nanofibers (CNF) on the polypropylene separator (COF@PP) is successfully designed as a battery separator to respond to the aforementioned issues. The COF@PP displays dual-functional characteristics with the aligned nanochannels and abundant functional groups of COFs, which can simultaneously modulate ion transport and SEI film components to build robust lithium metal anodes. The Li//COF@PP//Li symmetric cell exhibits stable cycling over 800 h with low ion diffusion activation energy and fast lithium ion transport kinetics, which effectively suppresses the dendrite growth and improves the stability of Li+ plating/stripping. Moreover, The LiFePO4//Li cells with COF@PP separator deliver a high discharge capacity of 109.6 mAh g^-1 even at a high current density of 3 C. And it exhibits excellent cycle stability and high capacity retention due to the robust LiF-rich SEI film induced by COFs. This COFs-based dual-functional separator promotes the practical application of lithium metal batteries.

Enabling 420 Wh kg-1 Stable Lithium-Metal Pouch Cells by Lanthanum Doping

Lithium (Li) metal, a promising anode for high-energy-density rechargeable batteries, typically grows along the low-surface energy (110) plane in the plating process, resulting in uncontrollable dendrite growth and unstable interface. Herein, an unexpected Li growth behavior by lanthanum (La) doping is reported: the preferred orientation turns to (200) from (110) plane, enabling 2D nuclei rather than the usual 1D nuclei upon Li deposition and thus forming a dense and dendrite-free morphology even at an ultrahigh areal capacity of 10 mAh cm^-2 . Noticeably, La doping further decreases the reactivity of Li metal toward electrolytes, thereby establishing a stable interface. The dendrite-free, stable Li anode enables a high average Coulombic efficiency of 99.30% at 8 mAh cm^-2 for asymmetric Li||LaF₃ -Cu cells. A 3.1 Ah LaF₃ -Li||LiNi_0.8 Co_0.1 Mn_0.1 O₂ pouch cell at a high energy density (425.73 Wh kg^-1 ) with impressive cycling stability (0.0989% decay per cycle) under lean electrolyte (1.76 g Ah^-1 ) and high cathode loading (5.77 mAh cm^-2 ) using this doped Li anode is further demonstrated.

Decreasing Interfacial Pitfalls with Self-Grown Sheet-Like Li2 S Artificial Solid-Electrolyte Interphase for Enhanced Cycling Performance of Lithium Metal Anode

Constructing a 3D composite Li metal anode (LMA) along with the engineering of artificial solid electrolyte interphase (SEI) is a promising strategy for achieving dendrite-free Li deposition and high cycling stability. The nanostructure of artificial SEI is closely related to the performance of the LMA. Herein, the self-grown process and morphology of in situ formed Li₂ S during lithiation of Cu_x S is studied systematically, and a large-sized sheet-like Li₂ S layer as an artificial SEI is in situ generated on the inner surface of a 3D continuous porous Cu skeleton (3DCu@Li₂ S-S). The sheet-like Li₂ S layer with few interfacial pitfalls (Cu/Li₂ S heterogeneous interface) possesses enhanced diffusion of Li ions. And the continuous porous structure provides transport channels for lithium-ion transport. As a result, the 3DCu@Li₂ S-S presents a high Coulombic efficiency (99.3%), long cycle life (500 cycles), and high-rate performance (10 mA cm^-2 ). Furthermore, Li/3DCu@Li₂ S anode fabricated by thermal infusion method inherits the synergistic advantages of sheet-like Li₂ S and continuous porous structure. The Li/3DCu@Li₂ S anode shows significantly enhanced cycling life in both liquid and solid electrolytes. This work provides a new concept to design artificial SEI for LMA with high safe and high performance.

Codependent failure mechanisms between cathode and anode in solid state lithium metal batteries: mediated by uneven ion flux

An in-depth understanding of the degradation mechanisms is a prerequisite for developing the next-generation all solid-state lithium metal battery (ASSLMB) technology. Herein, synchrotron X-ray computed tomography (SXCT) together with other probing tools and simulation method were employed to rediscover the decaying mechanisms of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM)|Li₆PS₅Cl (LPSCl)|Li ASSLMB. It reveals that the detachment and isolation of NCM particles cause the current focusing on the remaining active regions of cathode. The extent of Li stripping and the likelihood of Li⁺ plating into LPSCl facing the active NCM particles becomes higher. Besides, the homogeneity of Li stripping/plating is improved by homogenizing the electrochemical reactions at the cathode side by LiZr₂(PO₄)₃ (LZP) coating. These results suggest a codependent failure mechanism between cathode and anode that is mediated by uneven Li ion flux. This work contributes to a holistic understanding of the degradation mechanisms in ASSLMBs and opens new opportunities for their further optimization and development.

Stable Anode-Free All-Solid-State Lithium Battery through Tuned Metal Wetting on the Copper Current Collector

A stable anode-free all-solid-state battery (AF-ASSB) with sulfide-based solid-electrolyte (SE) (argyrodite Li₆ PS₅ Cl) is achieved by tuning wetting of lithium metal on "empty" copper current-collector. Lithiophilic 1 µm Li₂ Te is synthesized by exposing the collector to tellurium vapor, followed by in situ Li activation during the first charge. The Li₂ Te significantly reduces the electrodeposition/electrodissolution overpotentials and improves Coulombic efficiency (CE). During continuous electrodeposition experiments using half-cells (1 mA cm^-2 ), the accumulated thickness of electrodeposited Li on Li₂ Te-Cu is more than 70 µm, which is the thickness of the Li foil counter-electrode. Full AF-ASSB with NMC811 cathode delivers an initial CE of 83% at 0.2C, with a cycling CE above 99%. Cryogenic focused ion beam (Cryo-FIB) sectioning demonstrates uniform electrodeposited metal microstructure, with no signs of voids or dendrites at the collector-SE interface. Electrodissolution is uniform and complete, with Li₂ Te remaining structurally stable and adherent. By contrast, an unmodified Cu current-collector promotes inhomogeneous Li electrodeposition/electrodissolution, electrochemically inactive "dead metal," dendrites that extend into SE, and thick non-uniform solid electrolyte interphase (SEI) interspersed with pores. Density functional theory (DFT) and mesoscale calculations provide complementary insight regarding nucleation-growth behavior. Unlike conventional liquid-electrolyte metal batteries, the role of current collector/support lithiophilicity has not been explored for emerging AF-ASSBs.

Low-temperature lithium-ion batteries: challenges and progress of surface/interface modifications for advanced performance

Lithium-ion batteries are in increasing demand for operation under extreme temperature conditions due to the continuous expansion of their applications. A significant loss in energy and power densities at low temperatures is still one of the main obstacles limiting the operation of lithium-ion batteries at sub-zero temperatures. In addition to electrodes and electrolytes, more attention should be paid to the electrode-electrolyte interface, considering that the total internal resistance of batteries at low temperatures is dominated by interfacial charge transfer resistance. Here, we first review the main interfacial processes in lithium-ion batteries at low temperatures, including Li⁺ solvation or desolvation, Li⁺ diffusion through the solid electrolyte interphase and electron transport. Then, recent progress on the electrode surface/interface modifications in lithium-ion batteries for enhanced low-temperature performance is presented in detail. The lasting challenges and perspectives regarding electrode/electrolyte interface control in low-temperature lithium-ion batteries are finally discussed.

Long-Cycling All-Solid-State Batteries Achieved by 2D Interface between Prelithiated Aluminum Foil Anode and Sulfide Electrolyte

All-solid-state batteries (ASSBs) with alloy anodes are expected to achieve high energy density and safety. However, the stability of alloy anodes is largely impeded by their large volume changes during cycling and poor interfacial stability against solid-state electrolytes. Here, a mechanically prelithiation aluminum foil (MP-Al-H) is used as an anode to construct high-performance ASSBs with sulfide electrolyte. The dense Li-Al layer of the MP-Al-H foil acts as a prelithiated anode and forms a 2D interface with sulfide electrolyte, while the unlithiated Al layer acts as a tightly bound current collector and ensures the structural integrity of the electrode. Remarkably, the MP-Al-H anode exhibits superior lithium conduction kinetics and stable interfacial compatibility with Li₆ PS₅ Cl (LPSCl) and Li₁₀ GeP₂ S₁₂ electrolytes. Consequently, the symmetrical cells using LPSCl electrolyte can work at a high current density of 7.5 mA cm^-2 and endure for over 1500 h at 1 mA cm^-2 . Notably, ≈100% capacity is retained for the MP-Al-H||LPSCl||LiCoO₂ full cell with high area loadings of 18 mg cm^-2 after 300 cycles. This work offers a pathway to improve the interfacial and performance issues for the application of ASSBs.

Role of Interfaces in Solid-State Batteries

Solid-state batteries (SSBs) are considered as one of the most promising candidates for the next-generation energy-storage technology, because they simultaneously exhibit high safety, high energy density, and wide operating temperature range. The replacement of liquid electrolytes with solid electrolytes produces numerous solid-solid interfaces within the SSBs. A thorough understanding on the roles of these interfaces is indispensable for the rational performance optimization. In this review, the interface issues in the SSBs, including internal buried interfaces within solid electrolytes and composite electrodes, and planar interfaces between electrodes and solid electrolyte separators or current collectors are discussed. The challenges and future directions on the investigation and optimization of these solid-solid interfaces for the production of the SSBs are also assessed.