A tough, resilient, and fluorinated solid-electrolyte interphase stabilizing lithium metal in carbonate electrolytes

The unstable interface between lithium metal anodes and carbonate-based electrolytes is a key challenge limiting the cycling lifespan of high-energy lithium metal batteries. Here, a resilient artificial solid electrolyte interphase (RASEI) was designed by regulating poly(hexafluorobutyl acrylate) (PHFBA) matrix with the benzene-containing bisphenol A ethoxylate dimethacrylate (BAED) crosslinker to address this issue. The rigid BAED molecule can finely tune the flexible PHFBA matrix, enabling superior resilience from 600% elongation to 90% compression with a high Young’s modulus of over 2 MPa. RASEI with these characteristics can accommodate large volume changes of lithium metal and ensure the intimate contact between the lithium metal and the RASEI during battery operation. Consequently, it facilitated homogeneous lithium deposition while mitigating parasitic side reactions. Thanks to the tough and resilient nature of the fluorinated RASEI, the long-term cycling of Li∣∣Li symmetric cells can be achieved for over 500 h at 1 mA cm−2and 1 mAh cm−2. The following post-mortem of cycled Li metal reveals that Li dendrite growth is effectively inhibited. Furthermore, the NCM811 pouch cell with a high cathode loading of 20 mg cm−2exhibits a capacity retention of over 85% after 200 cycles at 1 C.