"Peapod-like" Fiber Network: A Universal Strategy for Composite Solid Electrolytes to Inhibit Lithium Dendrite Growth in Solid-State Lithium Metal Batteries.

Solid-state lithium metal batteries (SSLMBs) are a promising energy storage technology, but challenges persist including electrolyte thickness and lithium (Li) dendrite puncture. A novel three-dimensional "peapod-like" composite solid electrolyte (CSEs) with low thickness (26.8 µm), high mechanical strength, and dendrite inhibition was designed. Incorporating Li7La3Zr2O12 (LLZO) enhances both mechanical strength and ionic conductivity, stabilizing the CSE/Li interface and enabling Li symmetric batteries to stabilize for 3000 h. With structural advantages, the assembled LFP||Li and NCM811||Li cells exhibit excellent cycling performance. In addition, the constructed NCM811 pouch cell achieves a high gravimetric/volumetric energy density of 307.0 Wh kg-1/677.7 Wh L-1, which can light up LEDs under extreme conditions, demonstrating practicality and high safety. This work offers a generalized strategy for CSE design and insights into high-performance SSLMBs.

Vertically-Aligned Card-House Structure for Composite Solid Polymer Electrolyte with Fast and Stable Ion Transport Channels.

All-solid-state lithium batteries (ASSLBs) are highly promising as next-generation energy storage devices owing to their potential for great safety and high energy density. This work demonstrates that composite solid polymer electrolyte with vertically-aligned card-house structure can simultaneously improve the high rate and long-term cycling performance of ASSLBs. The vertical alignment of laponite nanosheets creates fast and uniform Li+ ion transport channels at the nanosheets/polymer interphase, resulting in high ionic conductivity of 8.9 × 10-4 S cm-1 and Li+ transference number of 0.32 at 60 °C, as well as uniformly distributed solid electrolyte interphase. Such electrolyte is characterized by high mechanical strength, low flammability, excellent structural stability and stable ion transport channels. In addition, the ASSLB cell with the electrolyte and LiFePO4 cathode delivers a high discharge specific capacity of 124.8 mAh g-1, which accounts for 85.6% of its initial capacity after 500 cycles at 1C. The reasonable design through structural control strategy by interconnecting the vertically-aligned nanosheets open a way to fabricate high performance composite solid polymer electrolytes.

Build a High-Performance All-Solid-State Lithium Battery through Introducing Competitive Coordination Induction Effect in Polymer-Based Electrolyte.

Polymer-inorganic composite electrolytes (PICE) have attracted tremendous attention in all-solid-state lithium batteries (ASSLBs) due to facile processability. However, the poor Li+ conductivity at room temperature (RT) and interfacial instability severely hamper the practical application. Herein, we propose a concept of competitive coordination induction effects (CCIE) and reveal the essential correlation between the local coordination structure and the interfacial chemistry in PEO-based PICE. CCIE introduction greatly enhances the ionic conductivity and electrochemical performances of ASSLBs at 30 °C. Owing to the competitive coordination (Cs+…TFSI-…Li+, Cs+…C-O-C…Li+ and 2,4,6-TFA…Li…TFSI-) from the competitive cation (Cs+ from CsPF6) and molecule (2,4,6-TFA: 2,4,6-trifluoroaniline), a multimodal weak coordination environment of Li+ is constructed enabling a high efficient Li+ migration at 30 °C (Li+ conductivity: 6.25×10-4 S cm-1; tLi +=0.61). Since Cs+ tends to be enriched at the interface, TFSI- and PF6 - in situ form LiF-Li3N-Li2O-Li2S enriched solid electrolyte interface with electrostatic shielding effects. The assembled ASSLBs without adding interfacial wetting agent exhibit outstanding rate capability (LiFePO4: 147.44 mAh g-1@1 C and 107.41mAhg-1@2 C) and cycling stability at 30 °C (LiFePO4:94.65 %@200cycles@0.5 C; LiNi0.5Co0.2Mn0.3O2: 94.31 %@200 cycles@0.3 C). This work proposes a concept of CCIE and reveals its mechanism in designing PICE with high ionic conductivity as well as high interfacial compatibility at near RT for high-performance ASSLBs.

Dual Interface Compatibility Enabled via Composite Solid Electrolyte with High Transference Number for Long-Life All-Solid-State Lithium Metal Batteries.

The development of solid-state electrolytes (SSEs) effectively solves the safety problem derived from dendrite growth and volume change of lithium during cycling. In the meantime, the SSEs possess non-flammability compared to conventional organic liquid electrolytes. Replacing liquid electrolytes with SSEs to assemble all-solid-state lithium metal batteries (ASSLMBs) has garnered significant attention as a promising energy storage/conversion technology for the future. Herein, a composite solid electrolyte containing two inorganic components (Li6.25 Al0.25 La3 Zr2 O12 , Al2 O3 ) and an organic polyvinylidene difluoride matrix is designed rationally. X-ray photoelectron spectroscopy and density functional theory calculation results demonstrate the synergistic effect among the components, which results in enhanced ionic conductivity, high lithium-ion transference number, extended electrochemical window, and outstanding dual interface compatibility. As a result, Li||Li symmetric battery maintains a stable cycle for over 2500 h. Moreover, all-solid-state lithium metal battery assembled with LiNi0.6 Co0.2 Mn0.2 O2 cathode delivers a high discharge capacity of 168 mAh g-1 after 360 cycles at 0.1 C at 25 °C, and all-solid-state lithium-sulfur battery also exhibits a high initial discharge capacity of 912 mAh g-1 at 0.1 C. This work demonstrates a long-life flexible composite solid electrolyte with excellent interface compatibility, providing an innovative way for the rational construction of next-generation high-energy-density ASSLMBs.

Advances in Ordered Architecture Design of Composite Solid Electrolytes for Solid-State Lithium Batteries.

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.

Li+ Conduction in a Polymer/Li1.5Al0.5Ge1.5(PO4)3 Solid Electrolyte and Li-Metal/Electrolyte Interface.

The solid oxide electrolyte Li1.5Al0.5Ge1.5(PO4)3 (LAGP) with a NASICON structure has a high bulk ionic conductivity of 10-4 S cm-1 at room temperature and good stability in the air because of the strong P5+-O2- covalence bonding. However, the Ge4+ ions in LAGP are quickly reduced to Ge3+ on contact with the metallic lithium anode, and the LAGP ceramic has insufficient physical contact with the electrodes in all-solid-state batteries, which limits the large-scale application of the LAGP electrolyte in all-solid-state Li-metal batteries. Here, we prepared flexible PEO/LiTFSI/LAGP composite electrolytes, and the introduction of LAGP as a ceramic filler in polymer electrolytes increases the total ionic conductivity and the electrochemical stability of the composite electrolyte. Moreover, the flexible polymer shows good contact with the electrodes, resulting in a small interfacial resistance and stable cycling of all-solid-state Li-metal batteries. The influence of the external pressure and temperature on Li+ transfer across the Li/electrolyte interface is also investigated.

Enhancing Interfacial Contact in Solid-State Batteries with a Gradient Composite Solid Electrolyte.

Solid-state batteries promise to meet the challenges of high energy density and high safety for future energy storage. However, poor interfacial contact and complex manufacturing processes limit their practical applications. Herein, a simple strategy is proposed to enhance interfacial contact by introducing a gradient composite polymer solid electrolyte (GCPE), which is prepared by a facile UV-curing polymerization technique. The high-Li6.4 La3 Zr1.4 Ta0.6 O12 (LLZTO)-content side of the electrolyte exhibits high oxidation resistance (5.4 V versus Li+ /Li), making it compatible with a high-voltage cathode material, whereas the LLZTO-deficient side achieves excellent interfacial contact with the Li metal anode, facilitating uniform Li deposition. Benefiting from the elaborate composition and structure of GCPE films, the symmetric Li//Li cell exhibits a low-voltage hysteresis potential of 42 mV and a long cycle life of >1900 h without short-circuiting. The Li//LiFePO4 solid-state batteries deliver a capacity of 161.0 mA h g-1 at 60 °C and 0.1 C (82.4% capacity is retained after 200 cycles). Even at 80 °C, the cell still shows an outstanding capacity of 132.9 mAh g-1 at 0.2 C after 100 cycles. The design principle of gradient electrolytes provides a new path for achieving enhanced interfacial contact in high-performance solid-state batteries.

Stabilizing a Lithium Metal Battery by an In Situ Li2S-modified Interfacial Layer via Amorphous-Sulfide Composite Solid Electrolyte.

A novel strategy has been proposed to produce in situ Li2S at the interfacial layer between lithium anode and the solid electrolyte, by using an amorphous-sulfide-LiTFSI-poly(vinylidene difluoride) (PVDF) composite solid electrolyte (SLCSE). Besides retarding the decomposition of PVDF in CSE, the Li2S-modified interfacial layer (SMIL) also improves the wettability between lithium metal and SLCSE which in turn optimizes the lithium deposition process. Our density functional theory calculation results reveal that the migration energy barrier of Li passing through SMIL is much lower than that of Li passing through LiF-modified interfacial layer (FMIL) formed from the decomposition of PVDF. The as-prepared SLCSE shows a Li ionic transference number of 0.44 and Li ion conductivity of 3.42 × 10-4 S/cm at room temperature, and the Li||SLCSE||LiFePO4 cell exhibits an outstanding rate performance with a capacity of 153, 144, 131, and 101 mAh/g at a current density of 0.05, 0.10, 0.25, and 0.50 mA/cm2, respectively.

A general strategy for all-solid-state batteries with agglomeration-free and high conductivity achieved by improving the interface compatibility of fillers and polymer matrix.

Composite solid electrolytes (CSEs) composed of polymer matrix and inorganic fillers show considerable potential for applications in all-solid-state lithium (Li) metal batteries. However, challenges such as fillers agglomeration and low lithium ion transference number (tLi+) remain significant obstacles to the practical application of CSEs. Herein, a general strategy of graft polymerization on the fillers surface to modulate the interface compatibility with the polymer matrix is proposed, and CSEs are prepared to verify the feasibility. The microstructure and composition of the surface coating of the fillers are analyzed, with subsequent studies of the fillers distribution within the CSEs confirming the improved interface compatibility. The enhancement of interface compatibility facilitates uniform dispersion of fillers, thereby greatly improving the utilization of fillers. CSEs exhibits high ionic conductivity (0.163 mS·cm-1 at 30 °C) and tLi+ (0.77), which gives the battery excellent rate performance and cycle stability. Therefore, chemical grafting of polymer onto the fillers surface to enhance the interface compatibility with the polymer matrix represents a promising strategy for the practical application of solid-state batteries.

Insight into Multiple Intermolecular Coordination of Composite Solid Electrolytes via Cryo-Electron Microscopy for High-Voltage All-Solid-State Lithium Metal Batteries.

Polymer/ceramic-based composite solid electrolytes (CSE) are promising candidates for all-solid-state lithium metal batteries (SLBs), benefiting from the combined mechanical robustness of polymeric electrolytes and the high ionic conductivity of ceramic electrolytes. However, the interfacial instability and poorly understood interphases of CSE hinder their application in high-voltage SLBs. Herein, a simple but effective CSE that stabilizes high-voltage SLBs by forming multiple intermolecular coordination interactions between polyester and ceramic electrolytes is discovered. The multiple coordination between the carbonyl groups in poly(ε-caprolactone) and the fluorosulfonyl groups in anions with Li6.5La3Zr1.5Ta0.5O12 nanoparticles is directly visualized by cryogenic transmission electron microscopy and further confirmed by theoretical calculation. Importantly, the multiple coordination in CSE not only prevents the continuous decomposition of polymer skeleton by shielding the vulnerable carbonyl sites but also establishes stable inorganic-rich interphases through preferential decomposition of anions. The stable CSE and its inorganic-rich interphases enable Li||Li symmetric cells with an exceptional lifespan of over 4800 h without dendritic shorting at 0.1 mA cm-2. Moreover, the high-voltage SLB with LiNi0.5Co0.2Mn0.3O2 cathode displays excellent cycling stability over 1100 cycles at a 1C charge/discharge rate. This work reveals the underlying mechanism behind the excellent stability of coordinating composite electrolytes and interfaces in high-voltage SLBs.

Poly(ethylene oxide)-based composite solid electrolyte for long cycle life solid-state lithium metal batteries: Improvement of interface stability through a dual mechanism.

Solid-state lithium metal batteries (SSLMBs) are promising candidates for safe and high-energy-density next-generation applications. However, harmful interfacial decomposition and uneven Li deposition lead to poor ion transport, a short cycle life, and battery failure. Herein, we propose a novel poly(ethylene oxide) (PEO)-based composite solid electrolyte (CSE) containing succinonitrile (SN) and zinc oxide (ZnO) nanoparticles (NPs), which improves interface stability through a dual mechanism. (1) By anchoring bis(trifluoromethanesulfonyl)imide (TFSI) anions to ZnO, a reliable solid electrolyte interface (SEI) later with abundant LiF can be obtained to inhibit interface decomposition. (2) The immobilization of escaping SN molecules in the SEI layer by ZnO NPs promotes the self-polymerization of SN and facilitates charge transfer through the interface. As a result, the ion conductivity of the stainless steel-symmetrical battery reaches 1.1 × 10-4 S cm-1 at room temperature, and a LiFePO4 (LFP) full battery exhibits ultrahigh stability (800 cycles) at 0.5 C. Thus, the present study provides valuable insights for the development of advanced PEO-based SSLMBs.

Diversifying Ion-Transport Pathways of Composite Solid Electrolytes for High-Performance Solid-State Lithium-Metal Batteries.

The application of composite solid electrolytes (CSEs) in solid-state lithium-metal batteries is limited by the unsatisfactory ionic conductivity underpinned by the low concentration of free lithium ions. Herein, we propose an interface design strategy where an amine silane linker is employed as a coupling agent to graft the Li7La3Zr2O12 (LLZO) ceramic nanofibers to the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer matrix to enhance their interaction. The hydrogen bonding between amino-functionalized LLZO (NH2@LLZO) and PVDF-HFP not only effectively induces a uniform incorporation of high-content nanofibers (50 wt %) into the polymer matrix but also furnishes sufficient continuous surfaces to weaken the complexation between PVDF-HFP and Li-ion carriers. Additionally, introduction of the hydrogen bond and Lewis acid-base interplay strengthens the interfacial interactions between NH2@LLZO and lithium salts that release more free lithium ions for efficient interfacial transport. The impact of the linker's structure on the dissociation capacity of lithium salts is systematically studied from the steric effect perspective, which affords insights into interface design. Conclusively, the composite solid electrolyte achieves a high ionic conductivity (5.8 × 10-4 S cm-1) by synergy of multiple transport channels at ceramic, polymer, and their interface, which effectively regulates the lithium deposition behavior in symmetric cells. The excellent compatibility of the electrolyte with both LiFePO4 and LiNi0.8Co0.1Mn0.1O2 cathodes also results in a long lifetime and a high rate capability for full cells.

Solution-processed poly(vinylidene difluoride)/cellulose acetate/Li1+xAlxTi2-x(PO4)3 composite solid electrolyte for improving electrochemical performance of solid-state lithium-ion batteries at room temperature.

To enhance energy density and secure the safety of lithium-ion batteries, developing solid-state electrolytes is a promising strategy. In this study, a composite solid-state electrolyte (CSE) composed of poly(vinylidene difluoride) (PVDF)/cellulose acetate (CA) matrix, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt, and Li1.3Al0.3Ti1.7(PO4)3 (LATP) fillers is developed via a facile solution-casting method. The PVDF/CA ratio, LiTFSI, and LATP fractions affect the crystallinity, structural porosity, and thermal and electrochemical stability of the PVDF/CA/LATP CSE. The optimized CSE (4P1C-40LT/20F) presents a high ionic conductivity of 4.9 × 10-4 S cm-1 and a wide electrochemical window up to 5.0 V vs. Li/Li+. A lithium iron phosphate-based cell containing the CSE delivers a high discharge capacity of over 160 mAh g-1 at 25 °C, outperforming its counterpart containing PVDF/CA polymer electrolyte. It also exhibits satisfactory cycling stability at 1C with approximately 90 % capacity retention at the 200th cycle. Additionally, its rate performance is promising, demonstrating a capacity retention of approximately 80 % under varied rates (2C/0.1C). The increased amorphous region, Li+ transportation pathways, and Li+ concentration of the 4P1C-40LT/20F CSE membrane facilitate Li+ migration within the CSE, thus improving the battery performance.

A Comparatively Low Cost, Easy-To-Fabricate, and Environmentally Friendly PVDF/Garnet Composite Solid Electrolyte for Use in Lithium Metal Cells Paired with Lithium Iron Phosphate and Silicon.

Solid electrolytes may be the answer to overcome many obstacles in developing the next generation of renewable batteries. A novel composite solid electrolyte (CSE) composed of a poly(vinylidene fluoride) (PVDF) base with an active nanofiber filler of aluminum-doped garnet Li ceramic, Li salt lithium bis-(trifluoromethanesulfonyl)imide (LiTFSI), Li fluoride (LiF) stabilizing additive, and plasticizer sulfolane was fabricated. In a Li|CSE|LFP cell with this CSE, a high capacity of 168 mAh g-1 with a retention of 98% after 200 cycles was obtained, representing the best performance to date of a solid electrolyte with a PVDF base and a garnet inorganic filler. In a Li metal cell with Si and Li, it yielded a discharge capacity of 2867 mAh g-1 and was cycled 60 times at a current density of 100 mAh g-1, a significant step forward in utilizing a solid electrolyte of any kind with the desirable Si anode. In producing this CSE, the components and fabrication process were chosen to have a lower cost and improved safety and environmental impact compared with the current state-of-the-art Li-ion battery.

Robust Solid-State Na-CO2 Battery with Na2.7Zr2Si2PO11.7F0.3-PVDF-HFP Composite Solid Electrolyte and Na15Sn4/Na Anode.

Solid-state Na-CO2 batteries are a kind of energy storage devices that can immobilize and convert CO2. They have the advantages of both solid-state batteries and metal-air batteries. High-performance solid electrolyte and electrode materials are important for improving the performance of solid-state Na-CO2 batteries. In this work, we investigate the influence of fluorine doping on the structure and ionic conductivity of Na3Zr2Si2PO12 (NZSP). An ionic conductive solid electrolyte membrane was prepared by compositing the inorganic solid electrolyte Na2.7Zr2Si2PO11.7F0.3 (NZSPF3) with poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP). It shows an ionic conductivity of up to 2.17 × 10-4 S cm-1 at room temperature, a high sodium ionic transfer number of ∼0.70, a broad electrochemical window of ∼5.18 V, and better mechanical strength. Furthermore, we studied the Na15Sn4/Na composite foil with the ability to inhibit dendrite as the anode for solid-state Na-CO2 batteries. Through density functional theory (DFT) calculations, the Na15Sn4 particle has been verified with a strong sodiophilic property, which reduces the nucleation barrier during the deposition process, leading to a lower overpotential. The symmetric cell assembled with the composite solid-state electrolyte NZSPF3-PVDF-HFP and Na15Sn4/Na composite anode can inhibit the growth of Na dendrites effectively and maintain the stability of the whole cell structure. Solid-state Na-CO2 batteries assembled with Ru-carbon nanotube (Ru-CNTs) as cathode catalysts exhibit a high discharge capacity of 6371.8 mAh g-1 at 200 mA g-1, excellent cycling stability for 1100 h, and good rate performance. This work provides a promising strategy for designing high-performance solid-state Na-CO2 batteries.

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

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

Studies on Composite Solid Electrolytes with a Dual Selective Confinement Interface Structure of Anions for High-Performance Lithium Metal Batteries.

Solid-state lithium batteries (SSLBs) have attracted much attention due to their good thermal stability and high energy density. However, solid-state electrolytes with low conductivity and prominent interfacial issues have hindered the further development of SSLBs. In this research, inspired from a selective confinement structure of anions, a novel HMOF-DNSE composite solid electrolyte with a dual selective confinement interface structure is proposed based on the semi-interpenetrating structure generated by poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), poly(di-n-butylmethylammonium) bis(trifluoromethanesulfonyl)imide (PDADMATFSI), and a metal-organic frameworks MOF derivative (HMOF) as a filler. The dual-network structure of PVDF-HFP/PDADMATFSI combined with HMOF formed a dual selective confinement interface structure to confine out the movement of large anions TFSI-, thereby enhancing the transfer ability of Li+. Subsequently, the addition of HMOF further improves the transfer of Li+ by binding up TFSI- through its crystal structure. The results show that HMOF-DNSE possesses a high room-temperature ionic conductivity (0.7 mS cm-1), a wide electrochemical window (up to 4.5 V), and a high Li+ transfer number (tLi+) (0.56). LiFePO4/HMOF-DNSE/Li cell shows an excellent capacity of 141.5 mAh g-1 at 1C rate under room temperature, with a high retention of 80.1% after 500 cycles. The material design strategy, which is based on selective confinement interface structures of anions, offers valuable insights into enhancing the electrochemical performance of solid-state lithium batteries.

Rational Design of a Cross-Linked Composite Solid Electrolyte for Li-Metal Batteries.

The interfacial problem caused by solid-solid contact is an important issue faced by a solid-state electrolyte (SSE). Herein, a cross-linked composite solid electrolyte (CSE) poly(vinylene carbonate) (PVCA)─ethoxylated trimethylolpropane triacrylate (ETPTA)─Li1.5Al0.5Ge1.5(PO4)3 (LAGP) (PEL) is prepared by in situ thermal polymerization. The ionic conductivity and Li+ transference number (tLi+) of PEL increase significantly due to the addition of LAGP, which can reach 1.011 × 10-4 S cm-1 and 0.451 respectively. The electrochemical stable window is also widened to 4.68 V. Benefiting from the integrated interfacial structure, the assembled coin cell shows low interfacial resistance. The all-solid-state NCM622|PEL|Li coin cell exhibits an initial discharge capacity of 169.7 mA h g-1 and 70% capacity retention over 100 cycles at 0.2 C, demonstrating excellent cycling stability.

Construction of a High-Performance Composite Solid Electrolyte Through In-Situ Polymerization within a Self-Supported Porous Garnet Framework.

Composite solid electrolytes (CSEs) have emerged as promising candidates for safe and high-energy-density solid-state lithium metal batteries (SSLMBs). However, concurrently achieving exceptional ionic conductivity and interface compatibility between the electrolyte and electrode presents a significant challenge in the development of high-performance CSEs for SSLMBs. To overcome these challenges, we present a method involving the in-situ polymerization of a monomer within a self-supported porous Li6.4La3Zr1.4Ta0.6O12 (LLZT) to produce the CSE. The synergy of the continuous conductive LLZT network, well-organized polymer, and their interface can enhance the ionic conductivity of the CSE at room temperature. Furthermore, the in-situ polymerization process can also construct the integration and compatibility of the solid electrolyte-solid electrode interface. The synthesized CSE exhibited a high ionic conductivity of 1.117 mS cm-1, a significant lithium transference number of 0.627, and exhibited electrochemical stability up to 5.06 V vs. Li/Li+ at 30 °C. Moreover, the Li|CSE|LiNi0.8Co0.1Mn0.1O2 cell delivered a discharge capacity of 105.1 mAh g-1 after 400 cycles at 0.5 C and 30 °C, corresponding to a capacity retention of 61%. This methodology could be extended to a variety of ceramic, polymer electrolytes, or battery systems, thereby offering a viable strategy to improve the electrochemical properties of CSEs for high-energy-density SSLMBs.

Suppression of Dehydrofluorination Reactions of a Li0.33La0.557TiO3-Nanofiber-Dispersed Poly(vinylidene fluoride-co-hexafluoropropylene) Electrolyte for Quasi-Solid-State Lithium-Metal Batteries by a Fluorine-Rich Succinonitrile Interlayer.

Solid-state lithium-metal batteries have great potential to simultaneously achieve high safety and high energy density for energy storage. However, the low ionic conductivity of the solid electrolyte and large electrode/electrolyte interfacial impedance are bottlenecks. A composite solid electrolyte (CSE) that integrates electrospun Li0.33La0.557TiO3 (LLTO) nanofibers, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is fabricated in this work. The effects of the LLTO filler fraction and morphology (spherical vs fibrous) on CSE conductivity are examined. Additionally, a fluorine-rich interlayer based on succinonitrile, fluoroethylene carbonate, and LiTFSI, denoted as succinonitrile interlayer (SNI), is developed to reduce the large interfacial impedance. The use of SNI rather than a conventional ester-based interlayer (EBI) effectively decreases the Li//CSE interfacial resistance and suppresses unfavorable interfacial side reactions. The LiF- and CFx-rich solid electrolyte interphase (SEI), derived from SNI, on the Li metal electrode, mitigates the accumulation of dead Li and excessive SEI. Importantly, dehydrofluorination reactions of PVDF-HFP are significantly reduced by the introduction of SNI. A symmetric Li//CSE//Li cell with SNI exhibits a much longer cycle life than that of an EBI counterpart. A Li//CSE@SNI//LiFePO4 cell shows specific capacities of 150 and 112 mAh g-1 at 0.1 and 2 C (based on LiFePO4), respectively. After 100 charge-discharge cycles, 98% of the initial capacity is retained.