Sulfide solid electrolytes (SSEs) for all‐solid‐state Li metal batteries (ASSLMBs) are attracting increasing attention due to their ultrahigh ionic conductivity and good machinability. However, current SSEs generally suffer from inferior Li metal compatibility and poor air‐stability, which severely impede their practical applications for ASSLMBs. Herein, novel argyrodite‐based SSEs of Li6+2xP1−xBixS5−1.5xO1.5xCl are synthesized via the Bi, O co‐doping the Li6PS5Cl for the first time. By adjusting the concentrations of dopant, the optimized Li6.04P0.98Bi0.02S4.97O0.03Cl presents an ultrahigh ionic conductivity (3.4 × 10−3 S cm−1). Moreover, such electrolyte displays splendid structural stability after exposure to humid air and chlorobenzene, demonstrating admirable air‐stability and solvent‐stability. The mechanism of the enhanced air‐stability of oxide‐doped SSEs is profoundly understood by conducting first‐principles density functional theory calculations. In addition, the Li6.04P0.98Bi0.02S4.97O0.03Cl electrolyte triggers the generation of LiBi alloy at the anode interface, which plays a crucial role in reducing Li+ diffusion energy barriers and improving interfacial compatibility, leading to an ultrahigh critical current density of 1.1 mA cm−2 and splendid cyclic stability in Li symmetric cell. As a result, ASSLMBs equipped with either pristine or air‐exposed Li6.04P0.98Bi0.02S4.97O0.03Cl can deliver satisfying discharge specific capacity at room temperature.

In solid polymer electrolytes (SPEs) based Li-metal batteries, the inhomogeneous migration of dual-ion in the cell results in large concentration polarization and reduces interfacial stability during cycling. A special molecular-level designed polymer electrolyte (MDPE) is proposed by embedding a special functional group (4-vinylbenzotrifluoride) in the polycarbonate base. In MDPE, the polymer matrix obtained by copolymerization of vinylidene carbonate and 4-vinylbenzotrifluoride is coupled with the anion of lithium-salt by hydrogen bonding and the "σ-hole" effect of the CF bond. This intermolecular interaction limits the migration of the anion and increases the ionic transfer number of MDPE (t Li + = 0.76). The mechanisms of the enhanced t Li + of MDPE are profoundly understood by conducting first-principles density functional theory calculation. Furthermore, MDPE has an electrochemical stability window (4.9 V) and excellent electrochemical stability with Li-metal due to the CO group and trifluoromethylbenzene (ph-CF 3 ) of the polymer matrix. Benefited from these merits, LiNi 0.8 Co 0.1 Mn 0.1 O 2 -based solid-state cells with the MDPE as both the electrolyte host and electrode binder exhibit good rate and cycling performance. This study demonstrates that polymer electrolytes designed at the molecular level can provide a broader platform for the high-performance design needs of lithium batteries.

No abstract

All‐solid‐state lithium batteries (ASSLBs) employing sulfide solid electrolytes (SEs) promise sustainable energy storage systems with energy‐dense integration and critical intrinsic safety, yet they still require cost‐effective manufacturing and the integration of thin membrane‐based SE separators into large‐format cells to achieve scalable deployment. This review, based on an overview of sulfide SE materials, is expounded on why implementing a thin membrane‐based separator is the priority for mass production of ASSLBs and critical criteria for capturing a high‐quality thin sulfide SE membrane are identified. Moreover, from the aspects of material availability, membrane processing, and cell integration, the major challenges and associated strategies are described to meet these criteria throughout the whole manufacturing chain to provide a realistic assessment of the current status of sulfide SE membranes. Finally, future directions and prospects for scalable and manufacturable sulfide SE membranes for ASSLBs are presented.

Engineered cathode active materials are critical for the cycling stability and power capability of sulfide‐based all‐solid‐state lithium batteries (ASSBs), yet it is challenging to construct uniform coverage via a scalable approach. In addition, the implication of dielectric coatings for electronic migration blocking in the composite cathode is neglected habitually. A heuristic “polymer‐patched inorganic” cathode coating strategy is presented herein. Single‐crystalline LiNi0.6Co0.2Mn0.2O2 (SNCM) particles are uniformly coated with a hybrid layer comprising nanoscale Li1.4Al0.4Ti1.6(PO4)3 (LATP) and cyclized polyacrylonitrile (cPAN), via a scalable solution‐based method. The LATP coating ensures rapid Li+ transfer across the interface and offers high oxidation tolerance. cPAN partially‐submerges and patches the imperfections of the LATP coating layer, producing a high‐quality protective coating without compromising electronic transfer. Accordingly, sulfide‐based ASSBs employing the hybrid‐modified SNCM cathode demonstrate competitive electrochemical performance in terms of capacity retention (72.7% over 500 cycles, at 0.5 C), and rate capability (87.3 mAh g−1 at 2 C, 5 times that of the pristine SNCM). Significant improvements are attributed to the homogeneity and functionality of the coating, which mitigates parasitic reactions at the interface while simultaneously preserving indispensable electronic percolation. This work offers a brand‐new cathode coating protocol for sulfide‐based all‐solid‐state to achieve longevity and good power.

All-solid-state Li metal batteries (ASSLMBs) have been considered the most promising candidates for next-generation energy storage devices owing to their high-energy density and safety. However, some obstacles such as thick solid electrolyte (SSEs) and unstable interface between the solid-state electrolytes (SSEs) and the electrodes have restricted the practical application of ASSLBs. Here, the scalable polyimide (PI) film reinforced asymmetric ultrathin (~20 μm) composite solid electrolyte (AU-CSE) with a ceramic-rich layer and polymer-rich layer is fabricated by a both-side casting method and rolling process. The ceramic-rich layer not only acts as a "securer" to inhibit the lithium dendrite growth but also redistributes Li-ions uniform deposition, while the polymer-rich layer improves the compatibility with cathode materials. As a result, the obtained AU-CSE demonstrates an ionic conductivity of 1.44 × 10 −4 S cm −1 at 35°C. The PI-reinforced AU-CSE enables

Solid‐state polymer electrolytes (SPEs) for all‐solid‐state batteries (ASSBs) have received considerable attention owing to excellent processability, good flexibility, high safety levels, and superior thermal stability. However, the practical application of SPEs is currently restricted by their low ionic conductivity, narrow electrochemical oxidation window, and poor long‐term stability of lithium (Li) metal. These challenges are mainly related to the polymer molecular structures, the dynamic of the polymer electrolyte, and the polymer compound stability at the electrode‐electrolyte interface. In this review, we provide recent strategies and discuss strategies of interest for applications to high‐energy‐density ASSB, particularly the molecular design, ion‐transport dynamic mechanisms of solid polymer electrolytes, and organic‐inorganic composite. Based on recent work, perspectives on future research directions are discussed for developing solid polymer electrolytes.

No abstract