Self-adaptive interfacial glue for low-pressure sulfide-based all-solid-state lithium metal batteries

Abstract

All-solid-state lithium batteries (ASSLBs) face critical challenges in practical applications due to excessive stack pressure requirements and interfacial degradation. To solve the solid–solid interfacial contact problem, we propose a dual interfacial engineering strategy combining nano-engineered Li_6−xPS_5−xCl_1+x (LPSCl) electrolytes (D₅₀ = 0.36 µm) with a self-adaptive polyethylene-vinyl acetate/lithium difluoro(oxalato)borate (PEVA–LiDFOB) composite glue. This design establishes robust ionic networks while dynamically maintaining interfacial integrity through viscoelastic stress accommodation. The interfacial electrochemical stability on the cathode side is significantly enhanced, and the interfacial side reactions are effectively suppressed. The optimized ASSLBs with Li metal anodes achieve outstanding cyclability with 90.6% capacity retention over 1000 cycles at 1C and 61.4% after 9000 cycles at 2C at 10 MPa and RT. Practical pouch cells demonstrate 90.6% capacity retention after 100 cycles at a pressure of 2 MPa and RT. This work provides universal interfacial design principles for developing pressure-resilient ASSLB systems.