High performance porous poly(ethylene oxide)-based composite solid electrolytes

A single inorganic or organic solid-state electrolyte can't meet the requirements of commercial solid-state batteries, which motivates the composite solid electrolytes (CSEs). However, the room-temperature ionic conductivity, mechanical strength and interface stability of CSEs are still difficult to support the required cycling performance. Here we propose the design of high performance porous PEO-based CSEs via solvent boiling method, inspired by the gas foaming used in polymer porous scaffold field. Crystallization of the PEO chain segment could be suppressed by the pore structure which could also increase interface stability and reduce density. Therefore, the porous PEO/LLZTO CSEs prepared via solvent boiling exhibit enhanced Li-ion conductivity, mechanical strength, electrochemical and cycling stability. Especially, the porous PEO/SN/LLZTO CSEs prepared via solvent boiling exhibit an excellent Li-ion conductivity (2.26 x 10-4 S cm-1 at 25 celcius) and high cycling stability. In this work, the effects of the porous structure on PEO-based CSEs were systemically studied, providing a novel controllable strategy for designing high performance CSEs.