3D porous network gel polymer electrolyte with high transference number for dendrite-free LiO2 batteries

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. Li O 2 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 Li O 2 batteries.