Room-Temperature Rapid Self-Healing Polymer Binders for Si Anodes in Highly Cycling-Stable and Capacity-Maintained Lithium-Ion Batteries
Fei Wang, Xiang Ma, Yiren Li, Hongmei Liu, Qingping Wu, Xiang Guan, Hui Liu, Xiao Xia Wang, Jun Xu
Abstract
Silicon (Si) with high specific capacity has received increasing attention for rechargeable battery anode materials. However, particle pulverization as a result of the large volume expansion of Si anodes further aggravated electrochemical performance degradation during the process of charging and discharging. In this work, we report the room-temperature rapid self-healing polymer binders (Al/Alg-TUEG) synthesized via dynamic coordination bonds (Al–O) and hydrogen bonds from poly(ether-thioureas) (TUEG). The prepared polymer binders exhibit a peeling force of 4.2 N, a swelling ratio of 9.5%, and a recovery of 90% in 2 h at room temperature. As a result, the Si@Al/Alg-TUEG anodes stably cycle for 300 cycles at 0.5 C with a capacity retention rate of 77.4%. A high initial Coulombic efficiency (CE) of 87.2% and good rate performance are also achieved. In terms of full cell performance, both LiFePO 4 //Si@Al/Alg-TUEG and NCM811//Si@Al/Alg-TUEG display stable cycling for 100 cycles at 0.5 C. The capacity retention of both full cells reaches 93.8 and 92.5%. Good recoverability at high rates is also found. The superior electrochemical performance of the Si anode indicates that Al/Alg-TUEG polymer with rapid self-healing capability at room-temperature is one of the promising binder candidates for next-generation high-energy-density lithium-ion batteries.