An Innovative Polydopamine/Polyvinyl Alcohol Binder System for High-Performance Micro-Sized Silicon Anodes

Micro-sized silicon (Si) is expected to be widely used in the future lithium-ion battery industry due to its abundant resources, low price, and high energy density. However, the rapid capacity degradation resulting from its significant volume expansion remains a critical challenge. Herein, an innovative binder system for micro-sized Si anodes is presented. Utilizing a high-energy ball milling reaction, Si particles are coated with a thin polydopamine (PDA) layer, forming Si@PDA particles. Subsequently, a polyvinyl alcohol (PVA) binder is incorporated to form the Si@PDA/PVA binder system. The numerous hydroxyl groups in PDA form hydrogen bonds with PVA binder, establishing robust interactions among electrode components, thereby stabilizing the overall structure of the Si anode and maintaining the integrity of its electrical contacts. As a result, the obtained Si@PDA/PVA anode exhibits a high specific capacity of 1215 mAh g⁻¹ at 0.2 C after 100 cycles. In addition, the rate performance test demonstrates that it delivers a high capacity of over 800 mAh g⁻¹ at 3 C. This approach provides a promising strategy for the overall design of micro-sized Si electrodes, offering enhanced cyclic performance and durability.