UV-curable PVdF-HFP-based gel electrolytes with semi-interpenetrating polymer network for dendrite-free Lithium metal batteries

The gel polymer electrolytes have attracted great attention due to their potential in uniform deposition of lithium, formation of stable SEI, nontoxicity, non-flammability and no leakage. In this work, the PVdF-HFP based gel polymer electrolytes are synthesized by UV-curing method, and the PEGMA and PEGDA are employed to enhance the mechanical properties of the electrolyte by forming 3D semi-interpenetrating polymer network. The PVdF-based gel polymer electrolyte with high ionic conductivity of 4.13 × 10−3 s/cm at room temperature shows superior cycling (140mAh g−1 at 0.5C after 200 cycles) and rate performance (142 mAh g−1 at 0.1C, 123 mAh g−1 at 1C and 90 mAh g−1 at 2C) when LiFePO4 is used as cathode materials. Moreover, the PVdF-based gel polymer electrolyte displays promising performance under high voltage when the NCM523 is selected as cathode materials (136mAh g−1 at 0.5C after 50 cycles). The excellent electrochemical performance as well as high ionic conductivity of the electrolyte may be ascribed to the remarkable liquid absorbing ratio of PVdF-HFP and the 3D cross-linking structure with semi-interpenetrating polymer network formed during UV-curing process.