Polyfluorinated crosslinker-based solid polymer electrolytes for long-cycling 4.5 V lithium metal batteries

• Main Authors: Tang, Lingfei, Chen, Bowen, Zhang, Zhonghan, Ma, Changqi, Chen, Junchao, Huang, Yage, Zhang, Fengrui, Dong, Qingyu, Xue, Guoyong, Chen, Daiqian, Hu, Chenji, Li, Shuzhou, Liu, Zheng, Shen, Yanbin, Chen, Qi, Chen, Liwei
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Materials; Density Functional Theory; Electric Conductance
• Online Access: https://hdl.handle.net/10356/169768
• Institution: Nanyang Technological University

Solid polymer electrolytes (SPEs), which are favorable to form intimate interfacial contacts with electrodes, are promising electrolyte of choice for long-cycling lithium metal batteries (LMBs). However, typical SPEs with easily oxidized oxygen-bearing polar groups exhibit narrow electrochemical stability window (ESW), making it impractical to increase specific capacity and energy density of SPE based LMBs with charging cut-off voltage of 4.5 V or higher. Here, we apply a polyfluorinated crosslinker to enhance oxidation resistance of SPEs. The crosslinked network facilitates transmission of the inductive electron-withdrawing effect of polyfluorinated segments. As a result, polyfluorinated crosslinked SPE exhibits a wide ESW, and the Li|SPE|LiNi0.5Co0.2Mn0.3O2 cell with a cutoff voltage of 4.5 V delivers a high discharge specific capacity of ~164.19 mAh g-1 at 0.5 C and capacity retention of ~90% after 200 cycles. This work opens a direction in developing SPEs for long-cycling high-voltage LMBs by using polyfluorinated crosslinking strategy.