3D porous network gel polymer electrolyte with high transference number for dendrite-free Li[sbnd]O2 batteries

Abstract

Solid-state lithium battery is considered as the next generation energy storage device with high security and outstanding energy density. However the low ionic conductivity of the electrolyte seriously limits its practical application. Here, we reported a high-performance flexible gel electrolyte based on graphene oxide (GO) doped poly (vinylidene fluoride-hexafluoro pentaene) cross-linked with poly (ethylene oxide) (PHPG) through weak bond interaction. The polymer electrolyte shows a 3D porous structure with an ionic conductivity of 3.4 × 10−4 S cm−1 at room temperature. Moreover, Li ion transference number is about 0.58, which could greatly accelerate the fast transmission of cations and anions. As a result, the PHPG-based Li symmetrical battery (Li/PHPG/Li) can run stably >750 h at 0.5 mA cm−2, showing good stability and security due to the remarkable suppression of Li dendrite growth. LiO2 batteries assembled with PHPG membrane as electrolyte can operate over 300 cycles at high current density (1 mA cm−2), indicating excellent cycling performance. The excellent performance of PHPG makes PHPG a very promising electrolyte for next-generation solid-state LiO2 batteries.