Inorganic/organic composite binder with self-healing property for silicon anode in lithium-ion battery

Abstract

Silicon (Si) has garnered significant attention as a high-capacity anode material in high-energy density lithium-ion batteries (LIBs). Nevertheless, the huge volume variation of Si (>300%) during cycling results in rapid capacity deterioration, thereby impeding its commercial application. To confront this challenge, inorganic binder has been identified as a highly promising solution for Si anode due to its high bonding strength. Despite its effectiveness, the inorganic binder's limited elasticity hinders the rejuvenation of the impaired electrode structure. Hence, we devised an elasticity and self-healing composite binder, incorporating both inorganic and organic binders. The inorganic lithium metasilicate not only offers ample adhesion sites to Si but also establishes a protective coating layer on SiNPs. Simultaneously, the organic poly (vinyl alcohol) featuring a low glass transition temperature (72 °C) furnishes elasticity and a self-healing framework. Consequently, the Si anode shows exemplary cycling and rate performances. Additionally, the Si||NCM811 full cell attains a reversible capacity of 1.86 mAh/cm2 with a capacity retention of 67% after 50 cycles, indicating the commercial application potential of the composite binder. This study thus explores design strategies for composite binders, paving the way for high-performance Si anode.