Facile Li+ Transport in Interpenetrating O- and F-Containing Polymer Networks for Solid-State Lithium Batteries

Solid polymer electrolytes (SPEs) provide an intimate contact with electrodes and accommodate volume changes in the Li-anode, making them ideal for all-solid-state batteries (ASSBs); however, confined chain swing, poor ion-complex dissociation, and barricaded Li⁺-transport pathways limit the ionic conductivity of SPEs. This study develops an interpenetrating polymer network electrolyte (IPNE) comprising poly(ethylene oxide)- and poly(vinylidene fluoride)-based networked SPEs (O-NSPE and F-NSPE, respectively) and lithium bis(fluorosulfonyl) imide (LiFSI) to address these challenges. The  CF₂ / CF₃ segments of the F-NSPE segregate FSI⁻ to form connected Li⁺-diffusion domains, and  C O C segments of the O-NSPE dissociate the complexed ions to expedite Li⁺ transport. The synergy between O-NSPE and F-NSPE gives IPNE high ionic conductivity (≈1 mS cm⁻¹) and a high Li-transference number (≈0.7) at 30 °C. FSI⁻ aggregation prevents the formation of a space-charge zone on the Li-anode surface to enable uniform Li deposition. In Li||Li cells, the proposed IPNE exhibits an exchange current density exceeding that of liquid electrolytes (LEs). A Li|IPNE|LiFePO₄ ASSB achieves charge–discharge performance superior to that of LE-based batteries and delivers a high rate of 7 mA cm⁻². Exploiting the synergy between polymer networks to construct speedy Li⁺-transport pathways is a promising approach to the further development of SPEs.     

Mechanistic Investigation of Polymer-Based All-Solid-State Lithium/Sulfur Battery

Although employing solid polymer electrolyte (SPE) in all-solid-state lithium/sulfur (ASSLS) batteries is a promising approach to obtain a power source with both high energy density and safety, the actual performance of SPE-ASSLS batteries still lag behind conventional lithium/sulfur batteries with liquid ether electrolyte. In this work, combining characterization methods of X-ray photoelectron spectroscopy, in situ optical microscopy, and three-electrode measurement, a direct comparison between these two battery systems is made to reveal the mechanism behind their performance differences. In addition to polysulfides, it is found that the initial elemental sulfur can also dissolve into and diffuse through the SPE to reach the anode. Different from the shuttle effect that causes uniform corrosion on the anode in a liquid electrolyte, dissolved sulfur species in SPE unevenly passivate the anode surface and lead to the inhomogeneous Li⁺ plating/stripping at the anode/SPE solid-solid interface. Such inhomogeneity eventually causes void formation at the interface, which leads to the failure of SPE-ASSLS batteries. Based on this understanding, a protection interlayer is designed to inhibit the shuttling of sulfur species, and the modified SPE-ASSLS batteries show much-improved performance in cycle life.     

A Self-Limited Free-Standing Sulfide Electrolyte Thin Film for All-Solid-State Lithium Metal Batteries

All-solid-state (ASS) lithium metal batteries (LMBs) are considered the most promising next-generation batteries due to their superior safety and high projected energy density. To access the practically desired high energy density of ASS LMBs, an ultrathin solid-state electrolyte (SSE) film with fast ion-transport capability presents as an irreplaceable component to reduce the proportion of inactive materials in ASS batteries. In this contribution, an ultrathin (60  µ m), flexible, and free-standing argyrodite (Li₆PS₅Cl) SSE film is designed through a self-limited strategy. A chemically compatible cellulose membrane is employed as the self-limiting skeleton that not only defined the thinness of the sulfide SSE film but also strengthened its mechanical properties. The ionic conductivity of the SSE film reaches up to 6.3 × 10⁻³ S cm⁻¹ at room temperature, enabling rapid lithium-ion transportation. The self-limited SSE thin films are evaluated in various ASS LMBs with different types of cathode (sulfur and lithium titanate) and anode materials (lithium and lithium-indium alloy) at both mold-cell and pouch-cell levels, demonstrating a stable performance and high-rate capability. This study provides a general strategy for the rational design of an SSE thin film towards high-energy-density ASS batteries.     

Advances and Prospects in Improving the Utilization Efficiency of Lithium for High Energy Density Lithium Batteries

Lithium-ion batteries have attracted much attention in the field like portable devices and electronic vehicles. Due to growing demands of energy storage systems, lithium metal batteries with higher energy density are promising candidates to replace lithium-ion batteries. However, using excess amounts of lithium can lower the energy density and cause safety risks. To solve these problems, it is crucial to use limited amount of lithium in lithium metal batteries to achieve higher utilization efficiency of lithium, higher energy density, and higher safety. The main reasons for the loss of active lithium are the side reactions between electrolyte and electrode, growth of lithium dendrites, and the volume change of electrode materials during the charge and discharge process. Based on these issues, much effort have been put to improve the utilization efficiency of lithium such as mitigating the side reactions, guiding the uniform lithium deposition, and increasing the adhesion between electrolyte and electrode. In this review, strategies for high utilization efficiency of lithium are presented. Moreover, the remaining challenges and the future perspectives on improving the utilization of lithium are also outlined.     

Physio-Electrochemically Durable Dry-Processed Solid-State Electrolyte Films for All-Solid-State Batteries

The dry process is a promising fabrication method for all-solid-state batteries (ASSBs) to eliminate energy-intense drying and solvent recovery steps and to prevent degradation of solid-state electrolytes (SSEs) in the wet process. While previous studies have utilized the dry process to enable thin SSE films, systematic studies on their fabrication, physical and electrochemical properties, and electrochemical performance are unprecedented. Here, different fabrication parameters are studied to understand polytetrafluoroethylene (PTFE) binder fibrillation and its impact on the physio-electrochemical properties of SSE films, as well as the cycling stability of ASSBs resulting from such SSEs. A counter-balancing relation between the physio-electrochemical properties and cycling stability is observed, which is due to the propagating behavior of PTFE reduction (both chemically and electrochemically) through the fibrillation network, resulting in cell failure from current leakage and ion blockage. By controlling PTFE fibrillation, a bilayer configuration of SSE film to enable physio-electrochemically durable SSE film for both good cycling stability and charge storage capability of ASSBs is demonstrated.     

Modeling of Void-Mediated Cracking and Lithium Penetration in All-Solid-State Batteries

All-solid-state batteries (ASSBs) are expected to have an exceptional energy density and safety owing to the possibilities of direct usage of lithium as an anode and the suppression of dendrites by a solid-state electrolyte (SSE). However, recent experiments unveil discharging-induced voids in lithium-SSE interfaces and charging-induced cracks in SSE, wherein lithium penetration occurs. To avoid such cell failures, a theoretical model rendering high-credibility simulations is needed to assist ASSB designs. Herein, such a model coupling the electrochemical processes and mechanical responses of an ASSB are proposed, in which the kinetics of voids and cracks are the key ingredients. Numerical simulations based on the model reveal that void growth is the result of stripping with disparate diffusivity in the surface layer and the bulk of lithium. They bring about the non-uniform distribution of Li⁺ during electroplating, a damage zone near the interface, SSE cracking, and then lithium plating in the cracks. It is noted that the cracks and lithium dendrites revealed by the simulations are very similar to those observed in in situ experiments and that a high stack pressure cannot inhibit cracking and lithium penetration. Instead, suitable lateral compressive stresses can prevent SSE from cracking and therefore inhibit lithium dendrites.     

Nido-Hydroborate-Based Electrolytes for All-Solid-State Lithium Batteries

Hydroborate-based solid electrolytes have recently been successfully employed in high voltage, room temperature all-solid-state sodium batteries. The transfer to analogous lithium systems has failed up to now due to the lower conductivity of the corresponding lithium compounds and their high cost. Here LiB₁₁H₁₄ nido-hydroborate as a cost-effective building block and its high-purity synthesis is introduced. The crystal structures of anhydrous LiB₁₁H₁₄ as well as of LiB₁₁H₁₄-based mixed-anion solid electrolytes are solved and high ionic conductivities of 1.1 × 10⁻⁴ S cm⁻¹ for Li₂(B₁₁H₁₄)(CB₁₁H₁₂) and 1.1 × 10⁻³ S cm⁻¹ for Li₃(B₁₁H₁₄)(CB₉H₁₀)₂ are obtained, respectively. LiB₁₁H₁₄ exhibits an oxidative stability limit of 2.6 V versus Li⁺/Li and the proposed decomposition products are discussed based on density functional theory calculations. Strategies are discussed to improve the stability of these compounds by modifying the chemical structure of the nido-hydroborate cage. Galvanostatic cycling in symmetric cells with two lithium metal electrodes shows a small overpotential increase from 22.5 to 30 mV after 620 h (up to 0.5 mAh cm⁻²), demonstrating that the electrolyte is compatible with metallic anodes. Finally, the Li₂(B₁₁H₁₄)(CB₁₁H₁₂)  electrolyte is employed in a proof-of-concept half cell with a TiS₂ cathode with a capacity retention of 82% after 150 cycles at C/5.     

3D Ion-Conducting,Scalable, and Mechanically Reinforced Ceramic Film for High Voltage Solid-State Batteries

Concerning the safety aspects of Li⁺ ion batteries, an epoxy-reinforced thin ceramic film (ERTCF) is prepared by firing and sintering a slurry-casted composite powder film. The ERTCF is composed of Li⁺ ion conduction channels and is made of high amounts of sintered ceramic Li_1+xTi_2-xAl_x(PO₄)₃ (LATP) and epoxy polymer with enhanced mechanical properties for solid-state batteries. The 2D and 3D characterizations are conducted not only for showing continuous Li⁺ ion channels thorough LATP ceramic channels with over 10⁻⁴ S cm⁻¹ of ionic conductivity but also to investigate small amounts of epoxy polymer with enhanced mechanical properties. Solid-state Li⁺ ion cells are fabricated using the ERTCF and they show initial charge–discharge capacities of 139/133 mAh g⁻¹. Furthermore, the scope of the ERTCF is expanded to high-voltage (>8 V) solid-state Li⁺ ion batteries through a bipolar stacked cell design. Hence, it is expected that the present investigation will significantly contribute in the preparation of the next generation reinforced thin ceramic film electrolytes for high-voltage solid-state batteries.     

High-Performance All-Solid-State Batteries Enabled by Intimate Interfacial Contact Between the Cathode and Sulfide-Based Solid Electrolytes

All-solid-state batteries (ASSBs) are considered the ultimate next-generation rechargeable batteries due to their high safety and energy density. However, poor Li-ion kinetics caused by the inhomogeneous distribution of the solid electrolytes (SEs) and complex chemo-mechanical behaviors lead to poor electrochemical properties. In this study, LiNi_0.8Co_0.1Mn_0.1O₂ (NCM) (core) – Li₆PS₅Cl (LPSCl) SEs (shell) particles (NCM@LPSCl) are prepared by a facile mechano-fusion method to improve the electrochemical properties and increase the energy density of ASSBs. The conformally coated thin SEs layer on the surface of NCM enables homogeneous distribution of SEs in overall electrode and intimate physical contact with cathode material even under volume change of cathode material during cycling, which leads to the improvement in Li-ion kinetics without the increase in solid electrolyte content. As a result, an ASSBs employing NCM@LPSCl with 4 mAh cm⁻¹ specific areal capacity exhibits robust electrochemical properties, including the improved reversible capacity (163.1 mAh g⁻¹), cycle performance (90.0% after 100 cycles), and rate capability (discharge capacity of 152.69, 133.80, and 100.97 mAh g⁻¹ at 0.1, 0.2, and 0.5 C). Notably, ASSBs employing NCM@LPSCl composite show reliable electrochemical properties with a high weight fraction of NCM (87.3 wt%) in the cathode.     

Progress and Perspectives of Lithium Aluminum Germanium Phosphate-Based Solid Electrolytes for Lithium Batteries

Solid-state lithium batteries are considered promising energy storage devices due to their superior safety and higher energy density than conventional liquid electrolyte-based batteries. Lithium aluminum germanium phosphate (LAGP), with excellent stability in air and good ionic conductivity, has gained tremendous attention over the past decades. However, the poor interface compatibility with Li anode, slow Li-ion conduction in thick pellets, and high-temperature sintering procedure limit the further development of LAGP solid electrolytes in practical applications. This review comprehensively summarizes the crystal structure, Li-ion conducting mechanism, and various synthesis methods, especially the latest thin-film preparation approach. The underlying reason for Li/LAGP interfacial instability is identified, followed by several advanced interface engineering strategies, for example, introducing a functional interlayer. The integration design of LAGP-based solid electrolytes and cathode is also highlighted to enable high-loading cathodes. Additionally, recent progress of lithium-oxygen and lithium-sulfur batteries with LAGP-based solid electrolytes is discussed. Moreover, the different Li-ion migration pathways, preparation procedures, and electrochemical performance of polymer-LAGP composite solid electrolytes in Li-ion batteries are introduced. Lastly, the remaining challenges and opportunities are proposed to encourage more efforts in this field. This review aims to provide fundamental insights and promising directions toward practical LAGP-based solid-state batteries.     

Ultrathin Layered Double Hydroxide Nanosheets Enabling Composite Polymer Electrolyte for All-Solid-State Lithium Batteries at Room Temperature

Solid electrolytes are the most promising substitutes for liquid electrolytes to construct high-safety and high-energy-density energy storage devices. Nevertheless, the poor lithium ion mobility and ionic conductivity at room temperature (RT) have seriously hindered their practical usage. Herein, single-layer layered-double-hydroxide nanosheets (SLN) reinforced poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) composite polymer electrolyte is designed, which delivers an exceptionally high ionic conductivity of 2.2 × 10⁻⁴ S cm⁻¹ (25  ° C), superior Li⁺ transfer number ( ≈ 0.78) and wide electrochemical window ( ≈ 4.9 V) with a low SLN loading ( ≈ 1 wt%). The Li symmetric cells demonstrate ultra-long lifespan stable cycling over ≈ 900 h at 0.1 mA cm⁻², RT. Moreover, the all-solid-state Li|LiFePO₄ cells can run stably with a high capacity retention of 98.6% over 190 cycles at 0.1 C, RT. Moreover, using LiCoO₂/LiNi_0.8Co_0.1Mn_0.1O₂, the all-solid-state lithium metal batteries also demonstrate excellent cycling at RT. Density functional theory calculations are performed to elucidate the working mechanism of SLN in the polymer matrix. This is the first report of all-solid-state lithium batteries working at RT with PVDF-HFP based solid electrolyte, providing a novel strategy and significant step toward cost-effective and scalable solid electrolytes for practical usage at RT.     

Fluorinated Bifunctional Solid Polymer Electrolyte Synthesized under Visible Light for Stable Lithium Deposition and Dendrite-Free All-Solid-State Batteries

Solid polymer electrolytes (SPEs) that can offer flexible processability, highly tunable chemical functionality, and cost effectiveness are regarded as attractive alternatives for liquid electrolytes (LE) to address their safety and energy density limitations. However, it remains a great challenge for SPEs to stabilize Li⁺ deposition at the electrolyte–electrode interface and impede lithium dendrite proliferation compared with LE-based systems. Herein, a design of solid-state fluorinated bifunctional SPE (FB-SPE) that covalently tethers fluorinated chains with polyether-based segments is proposed and synthesized via photo-controlled radical polymerization (photo-CRP). In contrast to the conventional non-fluorinated polyether-derived SPEs, FB-SPE is able to provide conducting Li⁺ transport pathways up to ≈5.0 V, while simultaneously forming a Li F interaction that can enhance Li anode compatibility and prevent Li dendrites growth. As a result, the FB-SPE exhibits outstanding cycling stability in Li||Li symmetrical cells of over 1500 operating hours at as high current density as 0.2 mA cm⁻². A thin and uniform Li deposition layer and LiF-rich SEI at the surface of Li anode are found, and stable cycling with average coulombic efficiencies of 99% is demonstrated in Li||LFP and Li||NCM all-solid-state batteries based on such bifunctional fluorinated SPEs. The interesting fluorine effect and effective self-suppression of lithium dendrites will inform rational molecular design of novel electrolytes and practical development of all-solid-state Li metal batteries.     

Impact of Fluorine-Based Lithium Salts on SEI for All-Solid-State PEO-Based Lithium Metal Batteries

LiF-rich solid-electrolyte-interphase (SEI) can suppress the formation of lithium dendrites and promote the reversible operation of lithium metal batteries. Regulating the composition of naturally formed SEI is an effective strategy, while understanding the impact and role of fluorine (F)-based Li-salts on the SEI characteristics is unavailable. Herein, LiFSI, LiTFSI, and LiPFSI are selected to prepare solid polymer electrolytes (SPEs) with poly(ethylene oxide) and polyimide, investigating the effects of molecular size, F contents and chemical structures (F-connecting bonds) of Li-salts and revealing the formation of LiF in the SEI. It is shown that the F-connecting bond is more significant than the molecular size and F element contents, and thus the performances of cells using LiPFSI are slightly better than LiTFSI and much better than LiFSI. The SPE containing LiPFSI can generate a high amount of LiF, and SPEs containing LiPFSI and LiTFSI can generate Li₃N, while there is no Li₃N production in the SEI for the SPE containing LiFSI. The preferential breakage bonds in LiPFSI are related to its position to Li anode, where Li-metal as the anode is important in forming LiF, and consequently the LiPFSI reduction mechanism is proposed. This study will boost other energy storage systems beyond Li-ion chemistries.     

Ambient-Temperature All-Solid-State Sodium Batteries with a Laminated Composite Electrolyte

This study presents a sodium-ion conductive laminated polymer/ceramic-polymer solid-state electrolyte for the development of room-temperature all-solid-state sodium batteries. At the negative electrode side, a negative-electrode-benign poly(ethylene oxide) (PEO) is used as a polymer matrix into which succinonitrile (SN) is integrated to improve the room-temperature Na⁺-ion conductivity. At the positive electrode side, a cathode-friendly poly(acrylonitrile) (PAN) serves as a polymer matrix into which a NASICON-type ceramic solid-electrolyte (Na₃Zr₂Si₂PO₁₂) powder is incorporated toward both the enhancement of Na⁺-ion conductivity and the prevention of Na dendrite from penetrating through the electrolyte membrane. Through a strategical management of composition, the PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ composite and the PEO-SN-NaClO₄ polymer deliver a balanced Na⁺-ion conductivity. Combining the two electrolyte layers, the laminated PEO-SN-NaClO₄/PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ solid electrolyte provides a Na⁺-ion conductivity of 1.36 × 10⁻⁴ S cm⁻¹ at room temperature. With respect to the anodic friendly feature of the PEO-SN-NaClO₄ layer and the cathodic friendly feature of the PAN-Na₃Zr₂Si₂PO₁₂-NaClO₄ layer, the laminated solid electrolyte presents a stable electrochemical window of 0–4.8 V. Room-temperature all-solid-state sodium batteries fabricated with the laminated solid electrolyte, a Na-metal negative electrode, and a Na₂MnFe(CN)₆ positive electrode exhibit remarkably stable cyclability.     

Constructing a Multifunctional Interlayer toward Ultra-High Critical Current Density for Garnet-Based Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs), exhibiting great advantages of high energy density and safety, are proposed to be the next generation energy storage system. However, the successful commercialization of garnet-based ASSLBs is hindered by the poor contact between solid-state electrolytes (Li_6.25Ga_0.25La₃Zr₂O₁₂, LGLZO) and lithium anode, as well as low critical current density (CCD). Herein, an indium tin oxide (ITO) layer is prepared on LGLZO by ultrasonic spraying technique, where ITO reacts with molten lithium to form a composite interlayer, consisting of Li₁₃In₃, Li₂O, and LiInSn. Experiments and density functional theory calculations demonstrate that such a unique interlayer plays a multifunctional role in achieving simultaneously better interface wettability, uniform Li deposition, and dendrite suppression at Li/LGLZO interface. Consequently, the CCD of ITO-treated symmetric cell is increased to a record-high value of 12.05 mA cm⁻² at room temperature, which is expected to promote practical application of ASSLBs. Moreover, the Li/ITO@LGLZO/Li cell exhibits a low interfacial resistance of only 5.9 Ω cm² and performs stable electrochemical operations for over 2000 h at 2 mA cm⁻². The Li/ITO@LGLZO/LiFePO₄ full cell also delivers superior electrochemical performances, demonstrating the efficiency of the ITO layer.     

Toward the Advanced Next-Generation Solid-State Na-S Batteries: Progress and Prospects

Although batteries fitted with sodium metal anodes and sulfur cathodes are attractive for their higher energy density and lower cost, the threat of polysulfide migration in organic liquid electrolytes, uncontrollable dendrites, and corresponding safety issues has locked the deployment of the battery system. Introduction of solid-state electrolytes to replace conventional liquid-based electrolytes has been considered an effective approach to address these issues and further render solid-state sodium-sulfur battery (SSSSB) systems with higher safety and improved energy density. Nevertheless, the practical applications of SSSSB are still hampered by grand challenges, such as poor interfacial contact, sluggish redox kinetics of sulfur conversion, and Na dendrites. Currently, various strategies have been proposed and utilized to negate the problems within the solid-state battery. Herein, a timely and comprehensive review of emerging strategies to promote the development of SSSSB is presented. The critical challenges that prevent the real application of the SSSSB technique are analyzed initially. Subsequently, various strategies for boosting the development of SSSSB are comprehensively summarized, containing the developing of the advanced cathode and cathode/electrolyte interface, tailoring the solid electrolyte, and designing the stable anode and anode/electrolyte interface. Finally, further perspectives on stimulating the practical application of SSSSB technology are provided.     

Smart Construction of an Intimate Lithium | Garnet Interface for All-Solid-State Batteries by Tuning the Tension of Molten Lithium

All-solid-state lithium batteries (ASSBs) have the potential to trigger a battery revolution for electric vehicles due to their advantages in safety and energy density. Screening of various possible solid electrolytes for ASSBs has revealed that garnet electrolytes are promising due to their high ionic conductivity and superior (electro)chemical stabilities. However, a major challenge of garnet electrolytes is poor contact with Li-metal anodes, resulting in an extremely large interfacial impedance and severe Li dendrite propagation. Herein, an innovative surface tension modification method is proposed to create an intimate Li | garnet interface by tuning molten Li with a trace amount of Si₃N₄ (1 wt%). The resultant Li-Si-N melt can not only convert the Li | garnet interface from point-to-point contact to consecutive face-to-face contact but also homogenize the electric-field distribution during the Li stripping/depositing process, thereby significantly decreasing its interfacial impedance (1 Ω cm² at 25 °C) and improving its cycle stability (1000 h at 0.4 mA cm⁻²) and critical current density (1.8 mA cm⁻²). Specifically, the all-solid-state full cell paired with a LiFePO₄ cathode delivered a high capacity of 145 mAh g⁻¹ at 2 C and maintained 97% of the initial capacity after 100 cycles at 1 C.     

Polyether-b-Amide Based Solid Electrolytes with Well-Adhered Interface and Fast Kinetics for Ultralow Temperature Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries (SSLMBs) are highly desirable for energy storage because of the urgent need for higher energy density and safer batteries. However, it remains a critical challenge for stable cycling of SSLMBs at low temperature. Here, a highly viscoelastic polyether-b-amide (PEO-b-PA) based composite solid-state electrolyte is proposed through a one-pot melt processing without solvent to address this key process. By adjusting the molar ratio of PEO-b-PA to lithium bis(trifluoromethanesulphonyl)imide (ethylene oxide:Li = 6:1) and adding 20 wt.% succinonitrile, fast Li⁺ transport channel is conducted within the homogeneous polymer electrolyte, which enables its application at ultra-low temperature (−20 to 25 °C). The composite solid-state electrolyte utilizes dynamic hydrogen-bonding domains and ion-conducting domains to achieve a low interfacial charge transfer resistance (<600 Ω) at −20 °C and high ionic conductivity (25 °C, 3.7 × 10⁻⁴ S cm⁻¹). As a result, the LiFePO₄|Li battery based on composite electrolyte exhibits outstanding electrochemical performance with 81.5% capacity retention after 1200 cycles at −20 °C and high discharge specific capacities of 141.1 mAh g⁻¹ with high loading (16.1 mg cm⁻²) at 25 °C. Moreover, the solid-state SNCM811|Li cell achieves excellent safety performance under nail penetration test, showing great promise for practical application.     

Wide-Temperature,Long-Cycling,and High-Loading Pyrite All-Solid-State Batteries Enabled by Argyrodite Thioarsenate Superionic Conductor

Rechargeable FeS₂ battery has been regarded as a promising energy storage device, due to its potentially high energy density and ultralow cost. However, the short lifespan associated with the shuttle effect of polysulfides, large volume change, agglomeration of Fe⁰ nanoparticles, narrow operating temperature range, and sluggish reaction kinetics, greatly impede the application of rechargeable FeS₂ lithium-ion batteries. Herein, an all-solid-state battery (ASSB) coupling commercialized FeS₂ is proposed with a novel superionic conductor Li_6.8Si_0.8As_0.2S₅I (LASI-80Si) to overcome these challenges. The shuttle effect of polysulfides and volume change of FeS₂ are suppressed or completely eliminated in ASSB, due to solid-solid conversion of Li₂S/S and large stacking pressure, respectively. Furthermore, the operating temperature range (−60–60 °C) is significantly expanded by the ultra-high and temperature-insensitive ionic conductivity of LASI-80Si (E_a = 0.20 eV), along with the superior FeS₂/LASI-80Si interface stability. Thanks to the extra Li⁺ provided by Li₂S and LiI functional phases, the “bridge” effect of LiI on facile interfacial Li-ion conduction, and the enhanced reaction kinetics of LASI-80Si (${\sigma }_{L{i}^{+}}=$ 10.4 mS cm⁻¹), ASSBs with LASI-80Si deliver long cycle life (244 cycles at 0.1 C and 600 cycles at 1 C), superior rate capability (20 C), high areal mass loading (13.37 mg cm⁻²), and ultrahigh areal capacity (9.05 mAh cm⁻²). These inspiring results demonstrate the enormous potential of LASI-80Si and FeS₂ combination for practical application of wide-temperature and large-capacity ASSBs.     

Toward the Practical and Scalable Fabrication of Sulfide-Based All-Solid-State Batteries: Exploration of Slurry Process and Performance Enhancement Via the Addition of LiClO4

Sulfide-based all-solid-state batteries (ASSBs) have a wide application prospect because of the advantages of higher energy density and better intrinsic safety over conventional lithium-ion batteries (LIBs). The compatibility of sulfide-based electrolytes with various organic solvents and the possibilities of the slurry coating process with these systems remain veiled that limits the large-scale fabrication of sulfide-based ASSBs. In this study, polyvinylidene fluoride (PVDF) binder and isobutyl isobutyrate (IBB) are selected as the combination of binder and solvent to achieve scalable slurry process after examining the chemical and electrochemical compatibility of Li₆PS₅Cl (LPSC) solid electrolyte, PVDF, and IBB. A comparative investigation of sheet-type LiNi_0.83Co_0.11Mn_0.06O₂ (NCM811) electrodes and pellet-type NCM811 electrodes shows that PVDF hinders the transport of Li⁺ and electron, but it benignantly works as a buffer layer, which alleviates the side reaction in the composite cathode electrode. Further, PVDF is modified by LiClO₄ to facilitate interfacial Li⁺ transport, which improves the capacity retention of the cell at 0.5 C to 97.05% after 100 cycles. Finally, NCM811/graphite full-cell is successfully fabricated by the slurry coating process, which demonstrates the feasibility of practical and scalable fabrication of sulfide-based ASSBs with slurry process and its performance enhancement effect via LiClO₄ modification.