Asymmetric double-layer composite electrolyte with enhanced ionic conductivity and interface stabili

• 作 者: Binglu Zhao Luxiang Ma Kai Wu Mengxiong Cao Minggui Xu Xinxiang Zhang Wen Liu Jitao Chen
• 机 构: Beijing National Laboratory for Molecular Sciences,College of Chemistry and Molecular Engineering,Pe
• 出 处: 中国化学快报（英文版）
• 发表日期: 2021年1期
• 关键词: All-solid-state battery Polymer electrolyte Lithium metal anode Interfacial engi

All-solid-state Li metal battery has been regarded as a promising battery technology due to its high energy density based on the high capacity of lithium metal anode and high safety based on the all solid state electrolyte without inflammable solvent. However, challenges still exist mainly in the poor contact and unstable interface between electrolyte and electrodes. Herein, we demonstrate an asymmetric design of the composite polymer electrolyte with two different layers to overcome the interface issues at both the cathode and the anode side simultaneously. At the cathode side, the polypropylene carbonate layer has enough viscosity and flexibility to reduce the inter-facial resistance, while at the Li anode side, the polyethylene oxide layer modified with hexagonal boron nitride has high mechanical strength to suppress the Li dendrite growth. Owing to the synergetic effect between different components, the as-prepared double layer composite polymer electrolyte demonstrates a large electrochemical window of 5.17 V, a high ionic conductivity of 6.1×10 4 S/cm, and a transference number of 0.56, featuring excellent ion transport kinetics and good chemical stability. All-solid-state Li metal battery assembled with LiFePO4 cathode and Li anode delivers a high capacity of 150.9 mAh/g at 25 C and 0.1 C-rate, showing great potential for practical applications.