New UV-initiated lithiated-interpenetrating network gel-polymer electrolytes for lithium-metal batteries

A new lithiated-interpenetrating network gel-polymer electrolytes (LIPN-GPEs) is designed and fabricated by ultraviolet-irradiation radical polymerization. The LIPN-GPEs includes both cross-linked poly (lithiated 2-acrylamido-2-methylpropane sulfonic acid-co-polyethylene glycol acrylate) matrix C–P(AMPSLi-MPEGA) and polyacrylonitrile (C-PAN), which forms the interpenetrating framework. The interpenetrating network ensures the mechanical strength and flexibility that eliminates volume changes of lithium anode during lithium deposition/stripping process. Meanwhile, the LIPN-GPEs with better self-supporting nature and high ionic conductivity (2.5 × 10−3 S/cm) can promote the movement of lithium ion resulting in more uniform distribution, which realizes uniform lithium deposition with stable SEI composition. Therefore, the LIPN-GPEs indicates excellent interfacial stability towards lithium anode. Symmetrical lithium metal cell yields low overpotential of 50 mV over 4000 h at 0.5 mA cm−2. The LIPN-GPEs with optimized ratio exhibits wider electrochemical window (5.06 V vs. Li/Li+) at ambient temperature, which also possesses unexceptional thermal stability with decomposition temperature up to 400 °C. Especially, when assembled with high-voltage cathode LiCoO2 (LCO) and LiNi0.5Co0.2Mn0.3O2 (NCM523) as coin cells, the LIPN-GPEs reveals cycling performance, reflecting good high-voltage resistance characteristic. This work testifies that LIPN-GPEs through a convenient ultraviolet-irradiation radical polymerization provides a candidate for lithium metal battery, which furnishes application prospects in wearable devices.