An entanglement association polymer electrolyte for Li-metal batteries
Hangchao Wang, Yali Yang, Chuan Gao, Tao Chen, Song Jin, Yuxuan Zuo, Qiu Fang, Tonghuan Yang, Wukun Xiao, Kun Zhang, Xuefeng Wang, Dingguo Xia
Abstract
Abstract To improve the interface stability between Li-rich Mn-based oxide cathodes and electrolytes, it is necessary to develop new polymer electrolytes. Here, we report an entanglement association polymer electrolyte (PVFH-PVCA) based on a poly (vinylidene fluoride-co-hexafluoropropylene) (PVFH) matrix and a copolymer stabilizer (PVCA) prepared from acrylonitrile, maleic anhydride, and vinylene carbonate. The entangled structure of the PVFH-PVCA electrolyte imparts excellent mechanical properties and eliminates the stress arising from dendrite growth during cycling and forms a stable interface layer, enabling Li//Li symmetric cells to cycle steadily for more than 4500 h at 8 mA cm −2 . The PVCA acts as a stabilizer to promote the formation of an electrochemically robust cathode–electrolyte interphase. It delivers a high specific capacity and excellent cycling stability with 84.7% capacity retention after 400 cycles. Li 1.2 Mn 0.56 Ni 0.16 Co 0.08 O 2 /PVFH-PVCA/Li full cell achieved 125 cycles at 1 C (4.8 V cut-off) with a stable discharge capacity of ~2.5 mAh cm −2 .