Long-Life Sulfide All-Solid-State Battery Enabled by Substrate-Modulated Dry-Process Binder

Sulfide all-solid-state batteries (ASSBs) have been widely acknowledged as next-generation energy-storage devices due to their improved safety performance and potentially high energy density. Among the various fabrication methods of sulfide ASSBs, solvent-free dry-film processes have unique advantages including reduced costs, suppressed film delamination, thick electrodes, and high compatibility with sulfide solid electrolytes (SEs). However, the currently dominating binder for dry-film process polytetrafluoroethylene suffers from poor voltage stability and low viscosity, which leads to low Coulombic efficiency and poor cycling stability of sulfide ASSBs. Herein, a specially-designed treatment is developed to obtain a new type of dry binder, styrene-butadiene rubber (SBR), exploiting paraxylene and a NaCl substrate to dissolve and re-precipitate SBR for controlling its stacking state, micro-structure/morphology, density, and dispersion performance. The SE membrane prepared using this processed SBR exhibits ultra-high ionic conductivity (2.34 mS cm(-1)), contributing to excellent cycle stability of the corresponding sulfide ASSB (>84% capacity retention after 600 cycles at 0.3C).

Automated summary

Sulfide all-solid-state batteries (ASSBs) are considered as promising next-generation energy storage devices due to their improved safety performance and high energy density. Solvent-free dry-film processes have unique advantages, but the current binder used in these processes, polytetrafluoroethylene, has poor voltage stability and low viscosity. In this study, a specially-designed treatment is developed to obtain a new type of dry binder, styrene-butadiene rubber (SBR), which significantly improves the cycling stability and Coulombic efficiency of sulfide ASSBs.