Coupling two-dimensional fillers with polymer chains in solid polymer electrolyte for room-temperature dendrite-free lithium-metal batteries

The urgent demand for high security and high energy density all-solid-state batteries has generated a strong interest in polyethylene oxide (PEO)-based solid polymer electrolyte (SPE). However, devising a SPE with a high ionic conductivity without sacrificing mechanical properties remains a critical challenge. Herein, an interpenetrating polymer network electrolyte is designed by chemical grafting coupling, where 2D boron nitride nanosheets and poly(ethylene glycol)diacrylate were coupled by a silane coupling agent. A considerable intensification of mechanical strength has been achieved for the SPE via the graft-coupling strategy, and the interpenetrating network with BNNs leads to the generation of amorphous regions for fast Li-ion immigration. The electrolyte integrates high mechanical strength with enhanced room-temperature ionic conductivity, enabling a long-cycle stability dendrite-free Li||Li symmetrical cell, and prominent cyclic performance is demonstrated in full cells at room temperature. Our approach provides a broader promise for the practical applications of solid-state batteries.