Polymer/ceramic gel electrolyte with in-situ interface forming enhances the performance of lithium metal batteries
Xi Wu, Xiaohua Jie, Xinghua Liang, Liuyan Zhang, Jin Wang, Shufang Wu
Abstract
With the introduction of solid-state electrolytes, solid-state lithium-metal batteries face enormous challenges of low electrolyte ion conductivity and high electrode electrolyte interface impedance. Here, we adopt a strategy of combining rigidity and flexibility to design a polymer/ceramic composite gel electrolyte films (CSEs) with a fiber like structure and local defect channels for rechargeable lithium metal batteries . The CSEs synthesized in situ on LiFePO 4 electrode by ultraviolet (UV) curing method, which combines the high ionic conductivity of Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (LLZTO) ceramic particles and the flexibility of poly(vinylidene fluoride-co -hexafluoropropylene) (PVDF-HFP) polymer electrolyte . In order to investigate the effect of crosslinker on the performance of electrolytes, 1,6-hexanediol diacrylate (HDDA) and ethoxylated trimethylolpropane triacrylate (ETPTA) were used in the preparation process of ultraviolet (UV) curing method. A comparison was made between gel electrolytes using HDDA and ETPTA crosslinkers, electrolytes containing ETPTA exhibited good overall performance in terms of ion conductivity (7.89 × 10 −4 S cm −1 ), Li + transference number (0.63), glass transition temperature (−26.2 °C), good flexibility, thermal stability. As a result, the assembled LiFePO 4 ||electrolytes containing ETPTA||Li batteries exhibit excellent the first discharge capacity (151.9 mAh g −1 with 0.1C), good rate performance and its capacity retention rate is 93.1 % after 300 cycles. This study provides a new strategy for the rational design and process method of high-performance CSEs for rechargeable solid lithium metal batteries.