(606e) Self-Healing Polymer for High-Performance Si Anode in Lithium-Ion Batteries

Polymeric materials can offer a variety of functions such as good electronic and ionic conductivity, mechanical flexibility, stretchability and self-healing capability. These properties are of great interest for electronic and energy-related applications. In next-generation high-energy lithium-ion batteries, their electrode active materials (e.g., silicon, sulfur) suffer from mechanical and electronic degradation, which limits the battery capacity and cycling life time. In this presentation, we will show how to use novel functional polymers to solve some of the most critical issues related to silicon anodes. Specifically, a dynamic hydrogen-bonding based self-healing polymer is developed to effectively coat and bond onto silicon particle surface, which can maintain good electronic conductivity and mechanical integrity in electrodes over repeatedly charging/discharging. Therefore, silicon electrodes can be cycled with significantly improved stability. Typically, using low-cost large Si particles, we achieved stable cycling of over 500 cycles at moderate mass loading. Even with a high areal capacity of > 3mAh/cm², the electrodes can still be cycled stably over 120 cycles. Such performance is comparable or even better than that of the state-of-art Si nanostructure designs. Our polymer approach provides great promise to renovate electrode structure and improve battery performance by tuning their structures and compositions.