Multivariate Distribution Structured Anisotropic Inorganic Polymer Composite Electrolyte for Long-Cycle and High-Energy All-Solid-State Lithium Metal Batteries.

Solid polymer electrolytes are promising candidates for solid-state Li metal batteries owing to their favorable rheological properties and interfacial compatibility with cathodes and Li anodes. However, their limited ionic conductivity and low modulus lead to inferior electrochemical performance and dendrite growth. Herein, we developed a composite solid-state electrolyte comprising vermiculite sheets and a poly(vinylidene fluoride) (PVDF) matrix with multivariate distribution and an anisotropic structure. Within this assembly, some vermiculite sheets were suspended in the PVDF matrix to facilitate Li salt dissociation and Li transport, while others were tiled on the electrolyte surface, generating a dense, high-modulus LiSiO-rich solid electrolyte interphase via in situ electrochemical reduction, which further improved interfacial kinetics and suppressed dendrite growth. As a result, a high conductivity of 1.38 mS cm was achieved at room temperature, and the Li||Li cells displayed robust stability over 3000 h. The LiNiCoMnO||Li full cells delivered a specific capacity of 172 mAh g at 0.2 C and 86% capacity retention after 500 cycles at 0.5 C. Additionally, practical cycle performance at a high loading (4.4 mAh cm) was achieved in pouch cells. Overall, multivariate distribution and anisotropic structuring offers a novel perspective for the preparation of high-performance solid-state electrolytes.