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Abstract The low lithium‐ion conductivity of polyethylene oxide (PEO)‐based polymer electrolytes limits their application in solid‐state lithium batteries and related fields. Here, ionic liquids (ILs) are injected into hollow silicon nanorods (HSNRs) to prepare a composite solid polymer electrolyte (CSPE) with aligned HSNRs containing ILs (F‐ILs@HSNRs). Applying a magnetic field promoted uniform dispersion and orientation of F‐ILs@HSNRs in CSPE. The addition of F‐ILs@HSNRs reduced PEO crystallinity and formed Li+ transport pathways at the F‐ILs@HSNRs/PEO interface. Calculations and multi‐physics simulations reveal that ILs within F‐ILs@HSNRs contribute most to lithium‐ion conduction, followed by the F‐ILs@HSNRs/PEO interface. When F‐ILs@HSNRs are arranged perpendicular to the electrodes, the CSPE exhibits the shortest Li+ migration pathways, resulting in stable and efficient lithium‐ion conduction. The conductivity (2.14 × 10−4 S cm−1) and lithium‐ion migration number tLi+ (0.307) are the highest, being 125 times and 184% higher, respectively, than those of PEO‐LiTFSI, when compared to CSPEs with randomly arranged or parallel‐aligned F‐ILs@HSNRs. Furthermore, Li|CSPE|Li batteries and LiFePO4|CSPE|Li batteries display stable cycling for over 2000 h, with coulombic efficiency approaching 100%. Excellent electrochemical reversibility is also confirmed in the rate performance test.

In the current challenging energy storage and conversion landscape, solid‐state lithium metal batteries with high energy conversion efficiency, high energy density, and high safety stand out. Due to the limitations of material properties, it is difficult to achieve the ideal requirements of solid electrolytes with a single‐phase electrolyte. A composite solid electrolyte is composed of two or more different materials. Composite electrolytes can simultaneously offer the advantages of multiple materials. Through different composite methods, the merits of various materials can be incorporated into the most essential part of the battery in a specific form. Currently, more and more researchers are focusing on composite methods for combining components in composite electrolytes. The ion transport capacity, interface stability, machinability, and safety of electrolytes can be significantly improved by selecting appropriate composite methods. This review summarizes the composite methods used for the components of composite electrolytes, such as filler blending, embedded framework, and multilayer bonding. It also discusses the future development trends of all‐solid‐state lithium batteries (ASSLBs). [ABSTRACT FROM AUTHOR]

The commercial potential of composite polymer electrolytes (CPEs) is significant due to their ability to combine the advantages of both inorganic and polymer solid electrolytes. However, the unstable interface and insufficient ionic conductivity remain important challenges in practical applications of CPEs for achieving high-performance solid-state lithium batteries (SLBs). Herein, we construct a double-layer composite polymer electrolyte (D-CPE) by incorporating nanosized TiO 2 fillers with adjustable concentrations of oxygen vacancies into poly (ethylene oxide) (PEO)-based electrolyte composites. In the D-CPE structure, one CPE layer containing TiO 2 fillers with oxygen vacancies exclusively interfaces with the LiFePO 4 cathode, while the other CPE layer consisting of pristine TiO 2 fillers (with negatively charged surfaces) solely contacts the lithium anode. This design of D-CPE achieves high ionic conductivity, a broad electrochemical window, and interfacial stability without additional resistance at the electrolyte-electrolyte interface simultaneously. The LiFePO 4 /D-CPEs/Li battery exhibits excellent cycling stability at 0.1 C, maintaining a capacity of 157.2 mAh g−1 with a capacity retention rate of 99.1% after 100 cycles. Furthermore, even at 0 °C, it delivers an impressive discharge capacity of 133.1 mAh g−1 at 0.1 C. This work presents a simple and effective approach to achieving superior polymer-based electrolytes for high-performance solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

This study explores multi-component garnet-based materials as solid electrolytes for all-solid-state lithium batteries. Through a combination of computational and experimental approaches, we investigate the thermodynamic and structural properties of lithium lanthanum zirconium oxide garnets doped with various elements. Applying density functional theory, the influence of dopants on the thermodynamic stability of these garnets was studied. Probable atomic configurations and their impact on materials' properties were investigated with the focus on understanding the influence of these configurations on structural stability, phase preference, and ionic conductivity. In addition to the computational study, series of cubic-phase garnet compounds were synthesized and their electrochemical performance was evaluated experimentally. Our findings reveal that the stability of cubic phase in doped Li-garnets is primarily governed by enthalpy, with configurational entropy playing a secondary role. Moreover, we establish that the increased number of doping elements significantly enhances the cubic phase's stability. This in-depth understanding of materials' properties at atomic level establishes the basis for optimizing high-entropy ceramics, contributing significantly to the advancement of solid-state lithium batteries and other applications requiring innovative material solutions. [ABSTRACT FROM AUTHOR]

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The Li dendrite problem triggered by the inhomogeneous deposition of Li and the reduction of Li+ in the electrolyte has seriously hindered the practical application of garnet‐based solid‐state batteries. To address this issue, a multifunctional double layer (MDL) based on the phenomenon of segregation during welding is introduced between the garnet and the Li anode. BiLi3/LiCl3 interlayer with a double‐layer structure is constructed by modulating the cooling rate. The LiCl3 enriched on the electrolyte side exhibits extremely low electronic conductivity, effectively blocking electrons and preventing electrolyte attack. On the anode side, the BiLi3‐enriched layer regulates local current distribution, ensuring uniform deposition/exfoliation of Li and preventing dendrite formation at the interface. Furthermore, this welding‐based preparation method achieves a strong and secure connection between the metal electrode and the ceramic electrolyte. Hence, this Li|LLZTO‐MDL|Li battery with double‐layer special structural interfacial modification can realize a high critical current density of 2.9 mA cm−2 and can be stably cycled for more than 10 000 h at 0.3 mA cm−2. [ABSTRACT FROM AUTHOR]

This study explores multi-component garnet-based materials as solid electrolytes for all-solid-state lithium batteries. Through a combination of computational and experimental approaches, we investigate the thermodynamic and structural properties of lithium lanthanum zirconium oxide garnets doped with various elements. Applying density functional theory, the influence of dopants on the thermodynamic stability of these garnets was studied. Probable atomic configurations and their impact on materials’ properties were investigated with the focus on understanding the influence of these configurations on structural stability, phase preference, and ionic conductivity. In addition to the computational study, series of cubic-phase garnet compounds were synthesized and their electrochemical performance was evaluated experimentally. Our findings reveal that the stability of cubic phase in doped Li-garnets is primarily governed by enthalpy, with configurational entropy playing a secondary role. Moreover, we establish that the increased number of doping elements significantly enhances the cubic phase’s stability. This in-depth understanding of materials’ properties at atomic level establishes the basis for optimizing high-entropy ceramics, contributing significantly to the advancement of solid-state lithium batteries and other applications requiring innovative material solutions.

One of the effective methods to improve the energy density and safety of lithium metal batteries is to use composite solid electrolytes with high voltage and good performance. However, the low ionic conductivity at room temperature and the unsatisfactory Li+ migration number of composite solid electrolytes lead to the growth of lithium dendrites and the increase of internal resistance, which restricts the industrialization of composite electrolytes for solid-state lithium batteries. This work prepares a Li6.4La3Zr1.4Ta0.6O12 (LLZTO)/polyethylene oxide (PEO)/polyvinylidene fluoride (PVDF) composite electrolyte. In this "polymer in ceramic" type electrolyte, the combination of PEO with PVDF and LLZTO reduces the crystallinity of PEO and promotes the rapid migration of Li+ along the PEO polymer molecular chain through complexation and decomplexation. At the same time, LLZTO, which has an excellent ion conduction function, introduces new ion conduction channels when combined with PEO and PVDF, thereby further improving ion conductivity. The LP82 composite electrolyte has a Li+ migration number of 0.78 and an electrochemical stability window of 5.5 V and exhibits excellent flexibility. The Li/LP82 electrolyte/Li battery has a relatively stable voltage of 0.04 V at 0.1 mA cm−2 and a stable cycling of 1000 h. The discharge specific capacity of the LiFePO4/LP82/Li battery is 144.4 mA h g−1 at 0.1 C after 180 cycles, and the capacity retention is 90.7%. This work provides a good reference for the preparation of composite electrolytes with simple processes, high voltage, and high performance. [ABSTRACT FROM AUTHOR]

Solid‐state lithium batteries (SSLBs) have great development prospects in high‐security new energy fields, but face major challenges such as poor charge transfer kinetics, high interface impedance, and unsatisfactory cycle stability. Defect engineering is an effective method to regulate the composition and structure of electrodes and electrolytes, which plays a crucial role in dominating physical and electrochemical performance. It is necessary to summarize the recent advances regarding defect engineering in SSLBs and analyze the mechanism, thus inspiring future work. This review systematically summarizes the role of defects in providing storage sites/active sites, promoting ion diffusion and charge transport of electrodes, and improving structural stability and ionic conductivity of solid‐state electrolytes. The defects greatly affect the electronic structure, chemical bond strength and charge transport process of the electrodes and solid‐state electrolytes to determine their electrochemical performance and stability. Then, this review presents common defect fabrication methods and the specific role mechanism of defects in electrodes and solid‐state electrolytes. At last, challenges and perspectives of defect strategies in high‐performance SSLBs are proposed to guide future research. [ABSTRACT FROM AUTHOR]

[Display omitted] InCl 3 @Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 -F (InCl 3 @LATP-F) solid electrolyte powders are designed and fabricated by coating a uniform InCl 3 layer on the surface of F--doped Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP-F) solid powders via a feasible wet-chemical technique. The assembled Li/InCl 3 @LATP-F/Li cell can undergo longer cycles of 2500 h at 0.4 mA cm−2 without obvious increases in the overvoltage compared to 1837 h for the Li/LATP-F/Li cell, and the interfacial resistance demonstrates a sharp decrease from 3428 to 436 Ω for the Li/InCl 3 @LATP-F/Li cell during the first 500 h. Importantly, the assembled LiCoO 2 /InCl 3 @LATP-F/Li cell delivers a high discharge specific capacity of 126.4 mAh g−1 with a 95.42% capacity retention ratio after 100 cycles at 0.5 C , and the value easily returns to 112.9 mAh g−1 when the current density is abruptly set back to 0.1 C after different rate cycles. These improved results can be mainly attributed to the fact that the InCl 3 layer with a lithiophilic nature can react with lithium metal to form a Li-In alloy, which can guarantee homogeneous lithium ion flux to avoid the accumulation of ions/electrons across the interface and suppress the growth of lithium dendrites. Moreover, the InCl 3 layer can prevent direct contact of the LATP-F solid electrolyte and lithium metal to effectively alleviate the reduction reaction of Ti4+ and preserve the structural stability of the composite electrolyte. Therefore, this work may provide an effective strategy to engineer and regulate the interfacial stability between LATP solid electrolytes and lithium metal anodes for LATP-type solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

For high‐energy‐density lithium batteries, the research and development of solid‐state electrolytes is crucial. Inorganic‐organic composite electrolytes with high mechanical strength and ionic conductivity of inorganic ceramic electrolytes, as well as high interfacial compatibility of polymer electrolytes, have become a current research hotspot. Based on a brief discussion of lithium dendrite growth and Li+ ion transport mechanisms, this article provides a comprehensive review of the nanostructure design and performance of inorganic‐organic composite electrolytes in recent years, and focuses on the mechanism of homogeneous monolayer composite electrolytes and heterogeneous multilayer composite electrolytes to enhance the performance of electrolytes. In addition, the future prospect of inorganic‐organic composite electrolytes is discussed, providing practical guidance for researchers in this field. [ABSTRACT FROM AUTHOR]

Solid electrolyte lithium batteries are the next generation of advanced energy devices. The incorporation of solid electrolytes can significantly improve the safety issue of lithium‐ion batteries. Organic‐inorganic composite solid electrolytes (CSE) are promising candidates for solid‐state batteries, but their application is mainly limited by low ionic conductivity. Many studies have shown that the architecture of ordered inorganic fillers in CSE can act as fast lithium‐ion transfer channels by auxiliary means, thus significantly improving the ionic conductivities. This review summarises the recent advances in CSE with different dimensional inorganic fillers. Various effective strategies for the construction of ordered structures in CSE are then presented. The review concludes with an outlook on the future development of CSE. This review aims to provide researchers with an in‐depth understanding of how to achieve ordered architectures in CSE for advanced solid state lithium batteries. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF)-based composite solid electrolytes (CSEs) are attracting widespread attention due to their superior electrochemical and mechanical properties. However, the PVDF has a strong polar group -CF2-, which easily continuously reacts with lithium metal, resulting in the instability of the solid electrolyte interface (SEI), which intensifies the formation of lithium dendrites. Herein, Tetrafluoro-1,4-benzoquinone (TFBQ) was selected as an additive in trace amounts to the PVDF/Li-based electrolytes. TFBQ uniformly formed lithophilic quinone lithium salt (Li2TFBQ) in the SEI. Li2TFBQ has high lithium-ion affinity and low potential barrier and can be used as the dominant agent to guide uniform lithium deposition. The results showed that PVDF/Li-TFBQ 0.05 with a mass ratio of PVDF to TFBQ of 1:0.05 had the highest ionic conductivity of 2.39 × 10−4 S cm−1, and the electrochemical stability window reached 5.0 V. Moreover, PVDF/Li-TFBQ CSE demonstrated superior lithium dendrite suppression, which was confirmed by long-term lithium stripping/sedimentation tests over 2000 and 650 h at a current of 0.1 and 0.2 mA cm−2, respectively. The assembled solid-state LiNi0.6Co0.2Mn0.2O2||Li cell showed an excellent performance rate and cycle stability at 30 °C. This study greatly promotes the practical research of solid-state electrolytes. [ABSTRACT FROM AUTHOR]

Garnet-type Li7La3Zr2O12（LLZO） solid electrolytes have become the key materials for solid-state lithium batteries due to their high safety and stability to lithium metal. However, the practical application of LLZO based solid-state batteries is limited by the problems of the conductivity of garnet solid electrolyte ions and the high interface resistance caused by poor solid-solid interface contact. From the perspective of garnet LLZO structure, this paper discusses the lithium ion transport mechanism and reviews the strategies and latest achievements to improve ion conductivity. Aiming at the unavoidable interface problems of solid-state lithium batteries, the specific methods of optimizing the interface are summarized from the contact between the LLZO solid-state electrolytes and the solid-state electrodes. Finally, future research directions for garnet-type solid electrolytes are proposed to promote their development and application in all-solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

High ionic conductivity for solid electrolyte and stable electrode/electrolyte interface have always been the main requirements for solid-state lithium batteries. Herein, a high ionic conductive composite solid electrolyte (CSE) film was prepared by combining 1.3-dioxolanes (DOL) capable of in-situ polymerization with high ionic conductive Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3 (LAGP)ceramic fillers. The CSE film also shows high interface compatibility and stability with lithium metal. The optimized poly-DOL (PDOL)-30% LAGP CSE exhibits a desirable dense and uniform structure, which endows the CSE with a high ion conductivity of 4.63 × 10−4 S cm−1, a high ion migration number up to 0.73 and a wide electrochemical stability window of 5.1 V. The assembled high-voltage NCM622/PDOL-30%LAGP CSE/Li solid-state cell exhibits good rate and cycle performances with a capacity of 125 mAh/g at 2 C and a capacity retention of 76% at 0.5C after 400 cycles with an average Coulomb efficiency of 99.7%. The PDOL-30%LAGP CSE also possesses a high inhibition ability of lithium dendrites owing to the dense and uniform structure and the stable electrolyte/lithium electrode interface including Li–Ge, LiF and CF 3 components. The Li/CSE/Li cell maintains a relatively stable voltage up to 650 h at a current density of 0.1 mA/cm2. This high ionic conductive composite solid electrolyte film shows a good application prospect in high-voltage solid-state lithium batteries. [Display omitted] • High ionic conductive PDOL/LAGP composite solid electrolyte film was achieved. • This composite solid electrolyte provides high ion transport capacity and high electrochmical window. • 3.The electrode/electrolyte interface stability was greatly improved by forming stable SEI composite film. [ABSTRACT FROM AUTHOR]

A high-energy-density commercial ternary material NCM811 was used as cathode material for lithium metal battery, wth two kinds of bindersol based PVDF and aqueous CMC. As prepared PVDF-HFP/ LLZTO composte membrane was used as the solid electrolyte, and metallic ithium was used as the anode to assemble soiid ithium metal battery. Cyciing performance of the cell was tested at room temperature at a rate of 0. 2 C. Compared to NCM811 cathode using PVDF as the binder, cathode wth the CMC binder has a better stabiy and a higher cycle capacty retention ratio. The discharge capacty of cathode wth the CMC binder after 40 cycles is 137 mAh ⋅ g-1 and the capacty retention rate is 90%. This can be attributed to the good adheson between the binder and NCM particles, which can prevent the cathode crack and detach. However, the specitic dsscharge capacty of the cell wth the CMC binder ss relatively low. This can be attributed to the reaction between high nickel cathode material and aqueous solution, which leads to a decrease of active ithium in the surface of the cathode material. Further improvement ss needed for the commercialization of the CMC binder for NCM811 based cathodes. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF)-based composite solid electrolytes (CSEs) are attracting widespread attention due to their superior electrochemical and mechanical properties. However, the PVDF has a strong polar group -CF2-, which easily continuously reacts with lithium metal, resulting in the instability of the solid electrolyte interface (SEI), which intensifies the formation of lithium dendrites. Herein, Tetrafluoro-1,4-benzoquinone (TFBQ) was selected as an additive in trace amounts to the PVDF/Li-based electrolytes. TFBQ uniformly formed lithophilic quinone lithium salt (Li2TFBQ) in the SEI. Li2TFBQ has high lithium-ion affinity and low potential barrier and can be used as the dominant agent to guide uniform lithium deposition. The results showed that PVDF/Li-TFBQ 0.05 with a mass ratio of PVDF to TFBQ of 1:0.05 had the highest ionic conductivity of 2.39 × 10−4 S cm−1, and the electrochemical stability window reached 5.0 V. Moreover, PVDF/Li-TFBQ CSE demonstrated superior lithium dendrite suppression, which was confirmed by long-term lithium stripping/sedimentation tests over 2000 and 650 h at a current of 0.1 and 0.2 mA cm−2, respectively. The assembled solid-state LiNi0.6Co0.2Mn0.2O2||Li cell showed an excellent performance rate and cycle stability at 30 °C. This study greatly promotes the practical research of solid-state electrolytes.

All-solid-state lithium batteries (ASSB) are emerging as an effective and promising alternative to current technologies that use organic liquid electrolytes. Its main proposition is to mitigate the safety and environmental issues caused by the leakages and explosions of conventional cells through the development and use of solid electrolytes, in the form of polymer membranes, ceramic pellets, or even composites, which are a combination of both. In the present work, composite electrolytes of polyethylene oxide (PEO), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and Zr-doped niobium garnet oxides (Li 5+x La 3 Nb 2-x Zr x O 12 - LLNZ) were prepared. The addition of ceramic reduced the melting point and inhibited the formation of spherulite-type crystallization of the polymer. The ionic conductivities of the composites were slightly lower than the polymer but still high for composite electrolytes of this composition, around 10−4 S.cm−1. The obtained results were analyzed considering the findings reported by other researchers, and some factors for a high-performance composite electrolyte were detailed. Additionally, all the fabricated composites showed a broad electrochemical window, some even above 5.0 V. Thus, electrochemical measurements were conducted with NMC811 as the cathode. The half-cell exhibited a specific capacity of 185 mAh.g−1 at C/20 at 60 °C, and a capacity retention of 68% after 50 cycles at C/5. The results are promising and indicate the possibility of the use of high‑nickel cathodes in all-solid-state batteries to increase their energy density. Schematic representation of the lithium ions transport in solid composite electrolytes with different ceramic loadings. [Display omitted] • Solid composite electrolytes were prepared with PEO, LITFSI, and a Zr-doped Garnet. • All composites exhibited high ionic conductivities of ∼10−4 S/cm at 60 °C. • Electrochemical stability window above 5.0 V was observed for some samples. • Half-cell tests with NMC811 cathode resulted in 185 mAh.g−1 at 60 °C for C/20. [ABSTRACT FROM AUTHOR]

2 additive. It boosts conductivity, ensuring stability in LiTiN|LLZTO|LiTiN cells and high capacity in LFP full cells after long cycles, indicating potential for enhanced stability in lithium-metal batteries. [Display omitted] • TiN conversion addresses resistance challenges, boosting SSB performance. • TiN improves lithium-ion conductivity and reduces porosity in SSB structures. • Stable performance and high current density observed in LiTiN|LLZTO|LiTiN cells. • LFP full cells show high capacity and retention after 1000 cycles. • TiN promises enhanced cycle stability in lithium-metal batteries. Solid-state batteries (SSBs) represent a pivotal avenue of development owing to their superior energy density and enhanced safety profile. However, the widespread utilization about SSBs confronts challenges such as inadequate interfacial connectivity resulting in high resistance, dendrite formation, and volumetric fluctuations in the lithium metal anode during plating and stripping. In this study, we introduce an innovative and remarkably efficient approach, leveraging the transformative potential of TiN-induced conversion. This method yields a lithium-ion-conductive TiN material concurrently addressing pre-existing porosity. The LiTiN| LLZTO| LiTiN symmetric cell is particularly noteworthy for its remarkable long-term cycle stability, which exceeds 1000 h at 0.2 mA cm−2, and its remarkable critical current density of 1.4 mA cm−2 at 25 °C. By subjecting TiN, the formation of the Li-Ti-N phase is induced, thereby establishing an additional Li 3 N-conductive layer that significantly enhances battery performance. Of paramount significance is the validation of the exceptional attributes of the composite through the deployment of LiFePO 4 (LFP) full cells. In this configuration, the LFP coupled full cell manifests a remarkable discharge rate capacity of about 147 mAh g−1 at 1C, along with a noteworthy discharge capacity retention rate of 90 % even following 1000 charge and discharge cycles. These outcomes underscore the material's robust lithium affinity and uniform lithium-ion distribution, which together mitigate dendrite growth and enhance the cycle stability of lithium-metal batteries. [ABSTRACT FROM AUTHOR]

Elementary processes of electro mass transfer in the nanocomposite polymer electrolyte system by pulse field gradient, spin echo NMR spectroscopy and the high-resolution NMR method together with electrochemical impedance spectroscopy are examined. The new nanocomposite polymer gel electrolytes consisted of polyethylene glycol diacrylate (PEGDA), salt LiBF4 and 1—ethyl—3—methylimidazolium tetrafluoroborate (EMIBF4) and SiO2 nanoparticles. Kinetics of the PEGDA matrix formation was studied by isothermal calorimetry. The flexible polymer–ionic liquid films were studied by IRFT spectroscopy, differential scanning calorimetry and temperature gravimetric analysis. The total conductivity in these systems was about 10−4 S cm−1 (−40 °C), 10−3 S cm−1 (25 °C) and 10−2 S cm−1 (100 °C). The method of quantum-chemical modeling of the interaction of SiO2 nanoparticles with ions showed the advantage of the mixed adsorption process, in which a negatively charged surface layer is formed from Li+ BF4— ions on silicon dioxide particles and then from ions of the ionic liquid EMI+ BF4−. These electrolytes are promising for use both in lithium power sources and in supercapacitors. The paper shows preliminary tests of a lithium cell with an organic electrode based on a pentaazapentacene derivative for 110 charge–discharge cycles.

This investigation explores the fabrication of Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) electrolytes, specifically focusing on the evolution of densification and resulting stress within the sintered structure of LLZTO electrolytes. Through a combination of experimental methods and numerical simulations based on finite element analysis, this study clarifies the mechanisms underlying the enhanced densification and grain growth of LLZTO with the addition of the sintering aid, liquid metallic gallium, attributing these effects to the reduced activation energies. With elevated sintering temperatures or the addition of gallium, the fired LLZTO exhibits heightened conductive performance, with conductivity increasing from < 10−4 to > 10−4 S cm−1. The numerical simulations further elucidate the correlation between stresses and the agglomeration/distribution of components during sintering. Non-uniform component distribution and agglomeration significantly escalate stress levels by two to four orders, compromising the structural integrity of the sintered electrolytes. The imperative need to address these challenges in the early stages of battery fabrication becomes apparent for the successful developments of ceramic electrolytes and the corresponding solid-state lithium batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

Solid-state electrolytes (SSEs) with excellent stability and flexibility have been used to overcome the safety and stability issues associated with the liquid electrolyte used in lithium-ion batteries (LIBs). In this study, thin composite solid electrolytes (CSEs) based on poly(vinylidenefluoride-cohexafluoropropylene) (PVDF-HFP) with high mechanical strength were fabricated. Garnet-type Li 6.5 Ga 0.2 La 2.95 Rb 0.05 Zr 2 O 12 (Ga-Rb LLZO) with high ionic conductivity was added to investigate the improvements in mechanical strength and ionic conductivity. The CSEs with Ga-Rb LLZO added to PVDF-HFP were referred to as PVDF-HFP + LLZO (PHL). Next, the interfacial resistance of the CSEs was reduced by adding a low-molecular-weight poly(ethylene glycol) (PEG) polymer, and the improvement in ionic conductivity and Li transfer was investigated. The CSEs with Ga-Rb LLZO and PEG added to the PVDF-HFP were referred to as PVDF-HFP + LLZO + PEG (PHLP). The ionic conductivity of the fabricated CSEs was 6.58 × 10−10 S cm−1 for the PVDF-HFP sheet, which increased to 1.10 × 10−5 S cm−1 and 2.33 × 10−4 S cm−1 for PHL and PHLP, respectively, at 70 °C. PHLP also had a very high lithium transference number of 0.789, and exhibited a discharge capacity of 123.16 mAh g−1 and a capacity retention rate of 88.29% after 200 cycles at 0.33C and 70 °C. • Addition of PEG reduces the crystallinity of PVDF-HFP. • Lithium transference number is high at 0.789. • The electrochemical stability window of PHLP has a value of 5.1 V vs Li/Li +. [ABSTRACT FROM AUTHOR]

Solid polymer electrolyte (SPE) has been considered as promising candidate electrolyte for solid-state lithium metal battery. However, the low ion conductivity and poor interface stability seriously hinder the development of SPE. Introducing the functional filler is a commonly used and effective approach to solving these issues. The poor compatibility and ambiguous mechanism of action are currently the main challenges. In this study, we design and synthesize carbon dots (NSFCDs) with quaternary functional groups, which are introduced into the SPE in the polymerization process of hybrid polymer electrolyte (HPE). The detailed effect law of polyfunctional groups on the polymer chain structure, interface structure of electrolyte/electrode and ion migration is systematically revealed. The dense polymer network endows HPE with enhanced mechanical properties. Through the regulation of polymer segments, the coordination environment of lithium ions is altered, promoting ion transport. The solid electrolyte interface (SEI) induced by NSFCDs and lithium salt anions effectively improves the morphology of lithium ion deposition and alleviates volume strain. As a result, the HPE based on polyethylene oxide (PEO) constructed by free radical polymerization of NSFCDs and polyethylene glycol diacrylate (PEGDA) exhibits excellent comprehensive performance, the assembled Li symmetric battery can cycle stably for 4000 h. [Display omitted] • Synthesis of high yield multifunctional group-doped carbon dots. • Carbon dots act as crosslinking centers to enhance mechanical strength and ionic conductivity. • Modulation of lithium-metal interfacial components to construct stable solid-state lithium-metal batteries. [ABSTRACT FROM AUTHOR]

The effect of the composition of liquid electrolytes in the bulk and at the interface with the LiFePO4 cathode on the operation of a solid-state lithium battery with a nanocomposite polymer gel electrolyte based on polyethylene glycol diacrylate and SiO2 was studied. The self-diffusion coefficients on the 7Li, 1H, and 19F nuclei in electrolytes based on LiBF4 and LiTFSI salts in solvents (gamma-butyrolactone, dioxolane, dimethoxyethane) were measured by nuclear magnetic resonance (NMR) with a magnetic field gradient. Four compositions of the complex electrolyte system were studied by high-resolution NMR. The experimentally obtained 1H chemical shifts are compared with those theoretically calculated by quantum chemical modeling. This made it possible to suggest the solvate shell compositions that facilitate the rapid transfer of the Li+ cation at the nanocomposite electrolyte/LiFePO4 interface and ensure the stable operation of a solid-state lithium battery.

Abstract Solid‐state lithium battery promises highly safe electrochemical energy storage. Conductivity of solid electrolyte and compatibility of electrolyte/electrode interface are two keys to dominate the electrochemical performance of all solid‐state battery. By in situ polymerizing poly(ethylene glycol) methyl ether acrylate within self‐supported three‐dimensional porous Li1.3Al0.3Ti1.7(PO4)3 framework, the as‐assembled solid‐state battery employing 4.5 V LiNi0.8Mn0.1Co0.1O2 cathode and Li metal anode demonstrates a high Coulombic efficiency exceeding 99% at room temperature. Solid‐state nuclear magnetic resonance results reveal that Li+ migrates fast along the continuous Li1.3Al0.3Ti1.7(PO4)3 phase and Li1.3Al0.3Ti1.7(PO4)3/polymer interfacial phase to generate a fantastic conductivity of 2.0 × 10−4 S cm−1 at room temperature, which is 56 times higher than that of pristine poly(ethylene glycol) methyl ether acrylate. Meanwhile, the in situ polymerized poly(ethylene glycol) methyl ether acrylate can not only integrate the loose interfacial contact but also protect Li1.3Al0.3Ti1.7(PO4)3 from being reduced by lithium metal. As a consequence of the compatible solid‐solid contact, the interfacial resistance decreases significantly by a factor of 40 times, resolving the notorious interfacial issue effectively. The integrated strategy proposed by this work can thereby guide both the preparation of highly conductive solid electrolyte and compatible interface design to boost practical high energy density all solid‐state lithium metal battery.

Solid‐state lithium battery promises highly safe electrochemical energy storage. Conductivity of solid electrolyte and compatibility of electrolyte/electrode interface are two keys to dominate the electrochemical performance of all solid‐state battery. By in situ polymerizing poly(ethylene glycol) methyl ether acrylate within self‐supported three‐dimensional porous Li1.3Al0.3Ti1.7(PO4)3 framework, the as‐assembled solid‐state battery employing 4.5 V LiNi0.8Mn0.1Co0.1O2 cathode and Li metal anode demonstrates a high Coulombic efficiency exceeding 99% at room temperature. Solid‐state nuclear magnetic resonance results reveal that Li+ migrates fast along the continuous Li1.3Al0.3Ti1.7(PO4)3 phase and Li1.3Al0.3Ti1.7(PO4)3/polymer interfacial phase to generate a fantastic conductivity of 2.0 × 10−4 S cm−1 at room temperature, which is 56 times higher than that of pristine poly(ethylene glycol) methyl ether acrylate. Meanwhile, the in situ polymerized poly(ethylene glycol) methyl ether acrylate can not only integrate the loose interfacial contact but also protect Li1.3Al0.3Ti1.7(PO4)3 from being reduced by lithium metal. As a consequence of the compatible solid‐solid contact, the interfacial resistance decreases significantly by a factor of 40 times, resolving the notorious interfacial issue effectively. The integrated strategy proposed by this work can thereby guide both the preparation of highly conductive solid electrolyte and compatible interface design to boost practical high energy density all solid‐state lithium metal battery. [ABSTRACT FROM AUTHOR]

High room-temperature ionic conductivity and mechanical property are essential for the application of solid electrolyte. In this work, a poly(vinylidene fluoride) (PVDF)-based composite polymer solid electrolyte membrane (CSE) incorporated with Li7La3Zr2O12 (LLZO) fillers and high-strength porous skeleton was prepared. The introduction of LLZO increased the ionic conductivity of PVDF at room temperature by reducing the crystallinity of PVDF matrix, and the addition of skeleton greatly improved the mechanical property of electrolyte membrane and inhibited the growth of lithium dendrites. The prepared PVDF-LLZO CSE has a room-temperature ionic conductivity of 1.75 × 10−4 S/cm, and the tensile strength reaches 95 MPa, which greatly enhanced the ability of lithium dendrite suppression. The assembled LiNi0.6Co0.2Mn0.2O2 (NCM622)/CSE/Li cell shows an initial capacity of 151 mAh/g with a retention capacity of 108 mAh/g after 100 cycles at the current density of 0.5 C. This ultrathin PVDF/LLZO CSE has a great application prospect in solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

Because of the high specific capacity and low cost, Ni-rich layered oxide (NRLO) cathodes are one of the most promising cathode candidates for the next high-energy-density lithium-ion batteries. However, they face structure and interface instability challenges, especially the battery safety risk caused by using an intrinsic flammable organic liquid electrolyte. In this regard, a solid electrolyte with high safety is of great significance to promote the development of energy storage. Among them, sulfide electrolytes are considered to be the most potential substitutes for liquid electrolytes because of their high ionic conductivity and good processing properties. Nevertheless, the interfacial incompatibility between the sulfide electrolyte and NRLO cathode is the critical challenge for high-performance sulfide all-solid-state lithium batteries (ASSLBs). In this review, we summarize the problems of the Ni-rich cathode/sulfide solid electrolyte interface and the strategies to improve the interface stability. On the basis of these insights, we highlight the scientific problems and technological challenges that need to be resolved urgently and propose several potential directions to further improve the interface stability. The objective of this study is to provide a comprehensive understanding and insightful recommendations for the enhancement of the sulfide ASSLBs with NRLO cathode.

Summary: Herein, the electrochemical characteristics of Li/LiFePO4 battery, comprising a new class of poly (ethylene oxide) (PEO) hosted polymer electrolytes, are reported. The electrolytes were prepared using lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) dopant salt and imidazolium ionic liquid‐based nanofluid (ionanofluid) as the plasticizer. Morphological, thermophysical, electrical, and electrochemical properties of these newly developed electrolytes were studied. Using FT‐IR spectroscopy, the interactions between dopant salt plasticizers and the host polymer, within the electrolytes, were evaluated. The optimized 30 wt% ionanofluid plasticized electrolyte exhibits a room temperature ionic conductivity of 6.33 × 10−3 S cm−1, wide electrochemical voltage window (~4.94 V vs Li/Li+) along with a moderately high value of lithium‐ion transference number (0.47). The values are substantially higher than that of similar wt% IL plasticized electrolyte (7.85 × 10−4 S cm−1, ~4.44 V vs Li/Li+ and ~ 0.28, respectively). Finally, the Li/LiFePO4 battery, comprising optimized 30 wt% ionanofluid plasticized electrolyte, delivers 156 mAh g−1 discharge capacity at 0.1 C rate and able to retain its 92% value after 50 cycles. Such a superior battery performance as compared to the IL plasticized electrolyte cell (137 mAh g−1 and 84% after 50 cycles at the same current rate) would endow this ionanofluid a very promising plasticizer to develop electrolytes for next‐generation lithium polymer battery. [ABSTRACT FROM AUTHOR]

Summary: High ionic conductivity at room temperature (RT) and good ion transport capability at electrode/electrolyte interface are fundamental requirements for high‐rate solid‐state lithium batteries (SSBs). In this work, we designed a poly (propylene carbonate) (PPC)‐based organic/inorganic composite solid electrolyte (CSE) membrane with high filling of tantalum‐doped lithium lanthanum zirconium oxide (LLZTO) and functionalized layers for enhancing the RT rate performance of SSB. The synergistic effect of LLZTO and interfacial functionalized layers endows the NCM622/CSE/Li battery with high‐rate and cycling performances at RT. The SSB with 20% LLZTO‐filled solid electrolyte shows the initial capacities of 162.0, 148.5 and 130.1 mAh g−1 at 1C, 2C, and 3C respectively, with retention capacities of 115.6, 104, and 100.6 mAh g−1 after 150 cycles. This strategy for an organic/inorganic CSE is of great practical significance for the development of high‐rate SSBs. [ABSTRACT FROM AUTHOR]

SUMMARY Solid polymer composite electrolyte (SPCE) with good safety, easy processability, and high ionic conductivity was a promising solution to achieve the development of advanced solid‐state lithium battery. Herein, through electrospinning and subsequent calcination, the Li0.33La0.557TiO3 nanowires (LLTO‐NWs) with high ionic conductivity were synthesized. They were utilized to prepare polymer composite electrolytes which were composed of poly (ethylene oxide) (PEO), poly (propylene carbonate) (PPC), lithium bis (fluorosulfonyl)imide (LiTFSI), and LLTO‐NWs. Their structures, thermal properties, ionic conductivities, ion transference number, electrochemical stability window, as well as their compatibility with lithium metal, were studied. The results displayed that the maximum ionic conductivities of SPCE containing 8 wt.% LLTO‐NWs were 5.66 × 10−5 S cm−1 and 4.72 × 10−4 S cm−1 at room temperature and 60°C, respectively. The solid‐state LiFePO4/Li cells assembled with this novel SPCE exhibited an initial reversible discharge capacity of 135 mAh g−1 and good cycling stability at a charge/discharge current density of 0.5 C at 60°C. [ABSTRACT FROM AUTHOR]

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For the first time, we investigate the electrochemical stability of Cu and Al current collectors in PEO/LiTFSI polymer electrolyte. The Cu and Al foils are passivated up to 3 and 5 V, respectively; namely, CuO for Cu and double layers of AlF 3 on the Al 2 O 3 passive layer for the Al foil in contact with PEO/LiTFSI polymer electrolyte. [Display omitted] • In a solid-state polymer electrolyte, the passivation of Cu and Al current collectors remains completely. • Our discovery introduces stability of Cu and Al when in contact with PEO/LiTFSI polymer electrolyte. • A Cu-O layer remains stable as a passive layer on Cu metal up to 3.6 V. • Al surface passivates with double layers consisting of outer Al-F and inner Al-O up to 5 V. • This study suggests suitability of Cu and Al in contact with solid-state polymer electrolyte. Recent interest in solid-state lithium batteries prevails in the battery community because of their superiority in terms of safety concerns. Many works have been reported for electrodes and electrolytes and their suitability for solid-state polymer electrolytes to adopt in lithium batteries. Herein, for the first time, we report on the electrochemical stabilities of Cu and Al current collectors in a polyethylene oxide (PEO)-based solid-state electrolyte containing lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. Our work on the electrochemical dynamic- and transient-mode polarization of these electrodes indicates that Cu metal undergoes Cu–O passivation below 3 V. The adhered Cu-F layer on the CuO passive layer may be beneficial to delay undesired reaction such as corrosion. And it is further confirmed that Al metal passivates stably even up to 5 V; namely, the Al surface forms double layers of the outer Al–F and inner Al–O layers. These F- and O-based layers are attributed to the combination of the Al and O from the reductively decomposed PEO and further progress of Al 2 O 3 and HF (H+ + F− →HF), decomposed from the PEO (H+) and TFSI− (F−). Therefore, we verify that successful passivation on Cu and Al metal surfaces facilitates their suitability as current collectors for solid-state polymer lithium batteries. [ABSTRACT FROM AUTHOR]

An in-situ electrochemical optical diagnosis is the key to the investigation of electrode interface during a redox reaction. Because the morphology changes particularly, dendrite formation, dendrite shapes, solid electrolyte interface formation and gas generation can be revealed visually. The challenge of ensuring uniform current density on a flat Li anode in a liquid electrolyte is addressed and uniform Li plating is demonstrated. The dendrite shape change under different reduction current density is discussed. The Li dendrite shape change and the performance of Li anodes with a surface lamination of graphite and red phosphate are used as examples to demonstrate the capability of the in-situ optical cell. An in-situ electrochemical optical cell used in the investigation of the increasingly popular solid-state Li batteries has its own challenges. Due to the untransparent nature of a solid-state electrolyte, an optical investigation on a solid-state electrolyte Li battery needs to be done by exposing the cross-section of the cell. In addition, it is very difficult to assemble an optical cell with a brittle and fragile solid-state electrolyte in a glove box. A set of formation and transfer dies, and an optical cell are introduced. The Li dendrite growth at the interface can be observed in a solid-state Li cell. [Display omitted] • Designs of In-situ cells to investigate Li dendrite formation real-time. • A cell for solid-state electrolyte revealing cross-section. • A cell for liquid electrolyte with unform current distribution. • Multiple examples to demonstrate the capability of the cell design. • Diffusion limited Li dendrite growth demonstration. [ABSTRACT FROM AUTHOR]

Abstract Solid polymer electrolytes show great application potential in the next-generation all-solid-state Li-ion batteries due to its safety, electrochemical stability, and easy-processing feature. However, low ionic conductivity of solid polymer electrolytes hinders their commercialization. Currently, dispersing ceramic fillers in polymer electrolytes has been proved to be a promising approach to address this issue. Herein, we introduce Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 fillers into polyacrylonitrile-LiClO 4 matrix and study the effects of Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 on chemical and electrochemical properties of the polyacrylonitrile-based electrolytes. The addition of Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 triggers the cyclization and segmentation of polyacrylonitrile chains, which improves the mechanical strength and thermal stability of the electrolytes. The effects of Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 on the electrochemical properties of the electrolytes are thoroughly investigated. The polyacrylonitrile-based electrolyte with 20 wt% Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 fillers shows a high ionic conductivity of 2.2 × 10−4 S cm−1 at 40 °C, a wide electrochemical window of 4.9 V, and much improved Li+ transference number and cycling stability in a Li||Li symmetric cell. In addition, a solid-state LiFePO 4 ||Li full cell is assembled and tested at room temperature, demonstrating the applicability of polyacrylonitrile-based electrolytes in all-solid-state batteries. Highlights • LLZO induces cyclization and segmentation of polyacrylonitrile (PAN). • LLZO boosts the electrochemical performance of PAN-based electrolytes. • LLZO enhances mechanical strength and thermal stability of PAN-based electrolytes. • PAN-LiClO 4 -LLZO electrolytes deliver good full-cell performance. [ABSTRACT FROM AUTHOR]

Gel electrolyte is one of the most direct and appropriate ways to solve the safety problem of battery before the most challenging technological hurdles to all solid-state batteries have not yet been overcame. A major challenge towards gel polymer electrolyte (GPE) is making an electrolyte that is effectively combine with electrochemical performance, thermal safety and the stability to lithium. Here, PVDF-HFP-LiTFSI/SiO 2 /EMITFSI polymer electrolyte composite membrane (ILGPE) is prepared via solution casting method, in which nano-silica and ionic liquid positively effect on the performance of polymer electrolytes, such as ionic conductivity, electrochemical stability and thermal safety stability. It remarkably enhances the interface compatibility between ILGPEs and lithium metal. Significantly, we characteristically elucidate the possible transmission mechanism and interaction within the materials of ILGPE. Furthermore, Li/LiFePO 4 battery based on such ILGPEs can exhibit fascinating interfacial stability and cycling performance. Herein, cells based on ILGPEs can overcome the drawbacks of solid electrolytes and volatile organic liquid electrolytes, which suggest a promising method for highly secure lithium batteries with appreciably enhanced performance. [ABSTRACT FROM AUTHOR]

Garnet Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolytes recently have attracted tremendous interest as they have the potential to enable all solid-state lithium batteries (ASSLBs) owing to high ionic conductivity (10 −3 to 10 −4  S cm −1 ), negligible electronic transport, wide potential window (up to 9 V), and good chemical stability. Here we present the key issues and challenges of LLZO in the aspects of ion conduction property, interfacial compatibility, and stability in air. First, different preparation methods of LLZO are reviewed. Then, recent progress about the improvement of ionic conductivity and interfacial property between LLZO and electrodes are presented. Finally, we list some emerging LLZO-based solid-state batteries and provide perspectives for further research. The aim of this review is to summarize the up-to-date developments of LLZO and lead the direction for future development which could enable LLZO-based ASSLBs. [ABSTRACT FROM AUTHOR]

Nano-sized fillers in a polymer matrix with good distribution can play a positive role in improving polymer electrolytes in the aspects of ionic conductivity, mechanical property and electrochemical performance of Li-ion cells. Herein, polyethylene oxide (PEO)/Li 3 PS 4 hybrid polymer electrolyte is prepared via a new in-situ approach. The ionic conductivities of the novel hybrid electrolytes with variable proportions are measured, and the optimal electrolyte of PEO-2%vol Li 3 PS 4 presents a considerable ionic conductivity of 8.01 × 10 −4  S cm −1 at 60 °C and an electrochemical window up to 5.1 V. The tests of DSC and EDXS reveal that the Li 3 PS 4 nanoparticles with better distribution, as active fillers scattering in the PEO, exhibit a positive effect on the transference of lithium ion and electrochemical interfacial stabilities. Finally, the assembled solid-state LiFePO 4 /Li battery presents a decent cycling performance (80.9% retention rate after 325 cycles at 60 °C) and excellent rate capacities with 153, 143, 139 and 127 mAh g −1 at the discharging rate of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C. It is fully proved that it is an advanced strategy to preparing the new organic/inorganic hybrid electrolytes for lithium-ion batteries applications. [ABSTRACT FROM AUTHOR]

Polymer–ceramic composite electrolytes are emerging as a promising solution to achieving high ionic conductivity, optimal mechanical properties, and good safety for developing high-performance all-solid-state rechargeable batteries. In this work, we report a garnet (Li 7 La 3 Zr 2 O 12 )-based hybrid solid electrolyte (HSE) membrane designed for high performance solid-state lithium batteries for the first time. The composite HSE membrane is composed of LLZO particles and PVDF–HFP polymer matrix. The solid-state lithium battery with this HSE membrane, Li metal anode and LiFePO 4 cathode exhibits an initial reversible discharge capacity of 120 mA h g −1 at a charge/discharge current density of 0.5 C at room temperature. This solid-state battery is used to store the energy harvested by a TENG at different rotation rates. The solid state battery can efficiently store the pulsed energy, especially for output at high frequencies. [ABSTRACT FROM AUTHOR]

Paramount attention has been paid on solid polymer electrolytes due to their potential in enhancement of energy density as well as improvement of safety. Herein, the composite electrolytes consisting of Li-salt-free polyethylene oxides and 200 nm-sized Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 particles interfacially wetted by [BMIM]TF 2 N of 1.8 μL cm −2 have been prepared. Such wetted ionic liquid remains the solid state of membrane electrolytes and decreases the interface impedance between the electrodes and the electrolytes. There is no release of the liquid phase from the PEO matrix when the pressure of 5.0 × 10 4 Pa being applied for 24 h. The interfacially wetted membrane electrolytes show the conductivity of 2.2 × 10 −4 S cm −1 at 20 °C, which is one order of magnitude greater than that of the membranes without the wetted ionic liquids. The conduction mechanism is related to a large number of lithium ions releasing from Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 particles and the improved conductive paths along the ion-liquid-wetted interfaces between the polymer matrix and ceramic grains. When the membranes being used in the solid-state LiFePO 4 /Li and LiFe 0.15 Mn 0.85 PO 4 /Li cells at 25 °C, the excellent rate capability and superior cycle stability has been shown. The results provide a new prospect for solid polymer electrolytes used for room-temperature solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

Solid-state lithium batteries (SSBs) have been widely researched as next-generation energy storage technologies due to their high energy density and high safety. However, lithium dendrite growth through the solid electrolyte usually results from the catastrophic interface contact between the solid electrolyte and lithium metal. Herein, a gradient nitrogen-doping strategy by nitrogen plasma is introduced to modify the surface and subsurface of the garnet electrolyte, which not only etches the surface impurities (e.g., Li 2 CO 3 ) but also generates an in situ formed Li 3 N-rich interphase between the solid electrolyte and lithium anode. As a result, the Li/LLZTON-3/Li cells show a low interfacial resistance (3.50 Ω cm 2 ) with a critical current density of about 0.65 mA cm -2 at room temperature and 1.60 mA cm -2 at 60 °C, as well as a stable cycling life for over 1300 h at 0.4 mA cm -2 at room temperature. A hybrid solid-state full cell paired with a LiFePO 4 cathode exhibits excellent cycling durability and rate performance at room temperature. These results demonstrate a rational strategy to enable lithium utilization in SSBs.

Composite polymer electrolytes (CPEs) are gaining increasing interest due to their combined advantages of polymer and inorganic ceramic. "Polymer-in-Ceramic" (PIC) system containing a large portion of ceramic fillers (higher than 50 wt%), possesses superior safety, electrochemical and mechanical properties, which render it a promising strategy for mass production of inorganic ceramic electrolytes. However, the poor organic-inorganic interface compatibility between polymer and ceramic leads to severe agglomeration of ceramic fillers within the polymer electrolyte, resulting in cracks in the membrane that impedes the transportation of lithium ions. Thus, two-dimensional (2D) g-C 3 N 4 nanosheets are introduced into the PIC-type electrolyte as a bridge between the organic and inorganic components to improve the homogeneity of the electrolyte membrane and build an effective transportation network. In this work, a PIC type g-C 3 N 4 / Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP)/Poly(vinylidene fluoride) (PVDF) electrolyte membrane with a thickness of 35.2 µm is prepared via a simple solution-casing method and delivers satisfactory all-around properties (a high conductivity of 5.9 × 10−4 S cm−1 at 25 ℃, a high lithium-ion transference number of 0.63 and superior thermal stability). To further evaluate its practicability, a solid-state lithium battery of LiNi 0.8 Mn 0.1 Co 0.1 O 2 |CPEs|Li is assembled and provides good cycling and rate performance at room temperature. This work proves the effectiveness of the 2D g-C 3 N 4 nanosheets in resolving the agglomeration issue and optimizing the electrochemical properties of LATP-based polymer-in-ceramic electrolyte, which provides a universal strategy to modify the PIC-type solid-state electrolytes. [Display omitted] • A flexible PIC-type LATP-based electrolyte modified with 2D g-C 3 N 4 was prepared. • g-C 3 N 4 can reduce the cracks caused by the agglomeration of LATP in a membrane. • An efficient ion transportation network has been constructed in the electrolyte. • The optimal properties of the electrolyte were achieved with 5 wt% g-C 3 N 4. [ABSTRACT FROM AUTHOR]

Agroydite Li 6 PS 5 Cl is one of the most promising solid electrolytes because of its high ionic conductivity and good processability. However, there are still many challenges with Li 6 PS 5 Cl and lithium anodes that prevent their industrialization, such as the growth of lithium dendrite and interfacial reactions. Interface modification of anodes has proven to be an effective method for solving these problems. Herein, we introduce Ag nanoparticles into the interface between Li 6 PS 5 Cl and metallic lithium and systematically investigate their interfacial properties. By incorporating silver nanoparticles, lithium dendrites can be depleted by forming Li–Ag alloys. Therefore, a denser and more stable interface between Li 6 PS 5 Cl and lithium metals is obtained. Benefiting from the above advantages, the Li/Li symmetrical battery with incorporated Ag nanoparticles exhibited an ultrahigh critical current density of up to 10 mA cm−2 and great cycling stability (more than 600 h). An all-solid-state battery with Ni-rich cathode and lithium metal anode demonstrates a high-capacity retention rate of 84% after 200 cycles at a current density of 0.5C. This study provides new insights into the construction of stable anode interfaces for the practical application of all-solid-state lithium batteries. • Ag nanoparticles contained interlayer applied between Li 6 PS5Cl and Li anode. • The interlayer enables an ultrahigh critical current density up to 10 mA cm−2. • Solid state lithium battery with interlayer exhibit enhanced cycling stability. • Ag-induced Li uniform deposition is responsible for the enhancement. [ABSTRACT FROM AUTHOR]

The development of promising solid-state lithium batteries has been a challenging task mainly due to the poor interfacial contact and high interfacial resistance at the electrode/solid-state electrolyte (SSE) interface. Herein, we propose a strategy for introducing a class of covalent interactions with varying covalent coupling degrees at the cathode/SSE interface. This method significantly reduces interfacial impedances by strengthening the interactions between the cathode and SSE. By adjusting the covalent coupling degree from low to high, an optimal interfacial impedance of 33 Ω cm -2 was achieved, which is even lower than the interfacial impedance using liquid electrolytes (39 Ω cm -2 ). This work offers a fresh perspective on solving the interfacial contact problem in solid-state lithium batteries.

Solid-state electrolytes with high ionic conductivity, large electrochemical window, good mechanical properties, and easy processability are needed for high-energy solid-state lithium batteries. In this work, composite membranes consisting of lithium garnet (i.e. Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 , LLZTO) particles and Li-salt-free polyethylene oxides (PEOs) are produced as solid-state electrolytes. Li-ion-conducting particles in nano-scale are crucial for the enhancement of conductivity and the membranes containing ~40 nm LLZTO particles exhibit conductivities nearly two orders of magnitude larger than those with the micro-scale ones, which is attributed to the difference in specific surface area related to the percolation effect. Compared to the conventional PEO doped with lithium salt, the insulating PEO in PEO:LLZTO membrane electrolyte is conducive to the suppression of lithium dendrite growth owing to prohibition of current flow. With PEO:LLZTO membrane electrolytes in conductivity of 2.1×10 −4 S cm −1 at 30 °C and 5.6×10 −4 S cm −1 at 60 °C, the solid-state LiFePO 4 /PEO:LLZTO/Li and LiFe 0.15 Mn 0.85 PO 4 /PEO:LLZTO/Li cells deliver energy densities of 345 Wh kg −1 (662 Wh L −1 ) and 405 Wh kg −1 (700 Wh L −1 ) (without the package weight or volume) with good rate capability and cycling performance. This study suggests that the conjunction of nano-scale Li-ion-conducting particles and an insulating polymer provides a promising solution to produce powerful solid-state electrolytes for high-performance solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

Poor interfacial compatibility between lithium (Li) metal anode and solid electrolyte is the main obstacle for solid-state Li metal batteries. To address which prefabricating an artificial solid electrolyte interphase (SEI) film on the surface of lithium anode is an effective strategy. Here, a bifunctional composite artificial SEI film with high ionic conductivity and interface compatibility is provided via in-situ forming poly-1,3-dioxolane (PDOL)/reduced graphene oxide (rGO) composite film on the surface of Li metal. The flexible high-ionic conductive PDOL improves the physical contact between the solid electrolyte and Li metal anode, and the rigid rGO effectively promotes the uniform plating of lithium ion (Li+) and suppresses the growth of Li dendrites. This rigid/flexible composite artificial SEI film not only boosts the interfacial transport of Li+, but also improves the interfacial compatibility between Li metal anode and solid electrolyte. Matching with PDOL solid electrolyte, the composite SEI film helps the Li symmetric cells to cycle stably for more than 350 h at a high current density of 0.3 mA/cm2 and an areal capacity of 0.3 mAh/cm2. Compared with the discharge specific capacity of pure Li metal anode, the discharge specific capacity of the assembled NCM622/PDOL & rGO-Li cell is increased by 17.5% at 2 C. This bifunctional composite SEI film provides a new idea for the surface modification of lithium metal anode. [Display omitted] • PDOL/rGO composite artificial SEI filmwas preparedbyspontaneous reaction. • Flexible and Li-friendlyPDOL improves interface contact and compatibility. • Rigid rGO inhibits lithium dendrite growth. [ABSTRACT FROM AUTHOR]

Succinonitrile (SN) plastic crystal electrolyte holds great promise for high-performance solid-state lithium metal batteries due to its high ionic conduction. However, the serious side reaction between SN and lithium anode always causes large interfacial resistance, deteriorating the battery capacity. Herein, we penetrated LiTFSI-SN (LSN) electrolyte into the interlayer channels of laminar metal-organic framework (MOF), then an ultra-thin and stable laminar LiTFSI–SN–MOF composite solid-state electrolyte (LSN-MOF CSE) was obtained. We demonstrate that the interlayer nanochannels for LSN electrolyte storage without sacrificing the mobility of SN molecules. Meanwhile, the unsaturated coordination of MOF, induced by Co/Ni metal sites, causes a horizontal arrangement of SN. Therefore, this electrolyte offers a remarkable ionic conductivity of 7.41 × 10−4 S cm−1 at 25 °C. Moreover, the interlayer nanochannels and covalent interaction of MOF synergistically suppress the migration of SN to lithium anode, thus improving the interface stability of lithium anode. Importantly, the assembled Li symmetrical cell performs stable operation over 800 h under 0.2 mA cm−2, and the LiFePO 4 /Li cell delivers excellent cycling stability of 148.2 mAh g−1 with a low capacity decay of 0.048% per cycle after 200 cycles under 0.2C and 25 °C. [Display omitted] • Ultrathin laminar MOF framework with 5.3-μm thick is prepared. • Nanochannels and metal sites confinement inhibit SN shuttling to lithium anode. • Horizontal arrangement of SN in MOF nanopores permits high ionic conductivity. • A high Li + transference number (0.59) is obtained. • Superior performance with capacity of 148.2 mAh g−1 at 25 °C is achieved. [ABSTRACT FROM AUTHOR]

Employing solid electrolytes in lithium-ion batteries is anticipated to be a solution to some issues originated from their organic electrolytes. However, solid-state lithium batteries had not been practicable, because ionic conductivities of lithium-ion conductive solid electrolytes had been very low. Therefore, many studies aiming at the development of solid-state lithium batteries have been focused on enhancement of ionic transport in solids. They have succeeded in enhancing the conductivity to be comparable to or even higher than that of liquids. At this stage, rate-determining step of the battery reactions is sometimes ionic transport at interface rather than bulk in the battery components. Since anomalous ionic conduction at the interface takes place in space-charge layers with ca. 10 nm in thickness, it will be controlled by 'nanoarchitectonics'. This paper reviews some interfacial nanoarchitectures that control the interfacial ionic conduction to enhance the performance of solid-state lithium batteries. [ABSTRACT FROM AUTHOR]