A novel cross-linked nanocomposite solid-state electrolyte with super flexibility and performance for lithium metal battery

Solid-state electrolyte batteries are considered as one of the promising next generation power sources. A novel cross-linked nanocomposite polymer electrolyte (CNPE) based on poly (propylene oxide)-poly (ethylene oxide)-poly (propylene oxide) triblock main chains and surface-modified SiO2 nanoparticles are prepared to establish a super flexible and stable polymer framework. The CNPE exhibits high ionic conductivity of 1.32 mS cm−1 at 20 °C and its electrochemical stability window reaches up to 6.5 V (versus Li+/Li). The favorable Li deposition behavior provided by CNPE films is identified by the stripping/plating test at a current density of 2.4 mA cm−2 for 1700 h. The CNPE films possess excellent mechanical stability (highly stretchable with ultimate elongation of 700%). Li/CNPE/LiFePO4 batteries deliver an initial discharge capacity of 160 mAh g−1 at 0.2 C, which is 94.1% of the theoretic capacity, and maintain the high specific capacity of 148 mAh g−1 at 0.5 C. This work provides a new approach toward designing high performance electrolyte for lithium metal batteries.