Room-Temperature Rapid Self-Healing Polymer Binders for Si Anodes in Highly Cycling-Stable and Capacity-Maintained Lithium-Ion Batteries

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 LiFePO4//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.