PVdF-HFP-Based Gel Polymer Electrolyte with Semi-Interpenetrating Networks For Dendrite-Free Lithium Metal Battery

摘要

The safety issues and lower energy density of the lithium metal batteries are the two main challenges that hinder their applications in the fields of electric vehicles and portable devices.In this work,the semi-interpenetrated polyvinylidene fluoride-hexafluoropropylene(PVdF-HFP)-based gel polymer electrolyte was synthesized through UV-curing method by employing the ethoxylated trimethylolpropane triacrylate(ETPTA)monomer.The semi-interpenetrating networks formed by polymerization of ETPTA and the high liquid absorption rate of the PVdF-HFP impart the as-prepared electrolyte with a high room temperature ionic conductivity of 3.17×10-3 s cm^(-1)and a high mechanical strength of 3.46 MPa.LiFePO4 was selected as cathode materials,and the active material loading of the cathode is about 4.2 mg cm-2.The electrolyte shows superior long-term cycling properties(127 mAh g^(-1)after 200 cycles at 0.5 C),excellent rate performance(113 mAh g^(-1)at1 C,80 mAh g^(-1)at 2 C,and the discharge capacity of 135 mAh g^(-1)can be restored when the rate goes back to 0.1 C)as well as good ability to inhibit the growth of lithium dendrite(about 150 h).The facile synthesis strategy and great electrochemical performance of the electrolyte make it a potential candidate for lithium metal batteries.