Gelatin network reinforced poly (vinylene carbonate-acrylonitrile) based composite solid electrolyte for all-solid-state lithium metal batteries

Abstract

Solid polymer electrolyte (SPE) has become one of the most promising candidate materials for building solid-state lithium batteries because of its excellent flexibility, expansibility and good interface compatibility with electrodes. However, SPE still has some problems such as low ionic conductivity at room temperature and narrow electrochemical window. Therefore, it is of great significance to develop polymer solid electrolyte with new structure to improve the comprehensive performance of the battery. In this work, Poly (vinylene carbonate-acrylonitrile) (PVN) was selected as the matrix of polymer electrolyte, and the network structure filled with biomass material gelatin was used as the skeleton. The composite solid polymer electrolyte (CSPE) composed of PVN, lithium bis (trifluoromethyl) sulfonimide (LiTFSI) and gelatin was prepared by simple solution casting method. The constructed PVN/LiTFSI/Gelatin (PLG) electrolyte has excellent ionic conductivity (3.47 × 10−4 S cm−1 at 60 °C) and wide electrochemical window (4.3 V). Li|10 %PLG CSPE|LiFePO4 battery has a capacity retention rate of 85 % after 1000 cycles of stable operation at 1C rate at 60 °C, and has excellent cycle performance and life. In addition, a low interface resistance enables highly reversible Li|Li symmetrical battery has a stably cycle of 1500 h at 0.1 mA cm−2 and has good interface compatibility. Therefore, PLG CSPE composite is a simple and effective strategy to obtain high-performance lithium batteries, which can realize the ultra-stable operation of solid lithium metal batteries.