Flexible Electrolyte and Cathode Membranes for All-Solid-State Batteries Fabricated by a One-Step Solvent Method

All-solid-state lithium batteries (ASSBs) are considered the most promising next-generation lithium-ion batteries attributed to their flame-resistant safety and high energy density. However, the rigidity and brittleness of inorganic solid-state electrolytes pose as key hurdles for the scale-up of production of ASSBs. In this research, an innovative one-step solvent method is proposed to fabricate a flexible Li₃InCl₆/poly(tetrafluoroethylene) (PTFE) electrolyte and composite cathode. The water/ethanol solvent serves as not only an emulsion breaker to form a fiber framework from PTFE dispersion but also a medium for the synthesis of Li₃InCl₆ electrolytes. This unique solvent synthetic method promotes infiltration and distribution of the electrolyte in the fiber framework while maintaining clay-like flexibility. The co-sintered electrolyte achieves high-temperature resistance (>200 °C) as well as high ionic conductivity at room temperature (0.38 mS cm^-1). On this basis, a composite cathode with high mass loading (11.4 mg cm^-2) is achieved by a similar synthetic process. The ASSB assembled with the electrolyte and cathode membrane cycles for 40 times at room temperature with a residual capacity of 61.7%. Both designs exhibit stretchable and environmentally friendly properties, which show great promise for the mass roll-to-roll production of ASSBs.