A High-Performance, Low-Cost and Recyclable Solid Electrolyte for Practical All-Solid-State Lithium-Based Batteries

The commercialization of all-solid-state lithium metal batteries (ASSLMBs) is constrained by the absence of a suitable solid electrolyte (SE) that simultaneously offers high ionic conductivity, favorable processability, electrochemical stability with electrodes, and cost-effectiveness. Herein, we report a novel polyoxometalate-based SE, Li₄SiW₁₂O₄₀ (LSWO), featuring a Keggin-type anion framework that constructs a three-dimensionally interconnected lithium-ion migration network, endowing it with a high room-temperature ionic conductivity (6.19 × 10^-4 S cm^-1). Additionally, the discrete Keggin-type anion framework endows the material with excellent compressibility, achieving a relative density of 90.3% under 300 MPa. A robust gradient interfacial passivation layer can also be generated to stabilize the Li metal electrode, enabling the Li/LSWO/Li symmetric cell to achieve a critical current density of 4.2 mA cm^-2 and sustain long-term cycling for over 2400 h at 0.2 mA cm^-2. Notably, the ASSLMBs with Li/LSWO/LiNi_0.8Mn_0.1Co_0.1O₂ configuration exhibit remarkable cycling stability, delivering capacity retentions of 93.3% after 140 cycles at 0.5 C in coin cells and 88.2% after 200 cycles at 0.5 C in pouch cells. Techno-economic analysis reveals that LSWO exhibits significant cost-effectiveness compared to representative SEs. The high-performance and low-cost LSWO SE presents a promising candidate to facilitate the commercialization of ASSLMBs.