Latent-Cross-Linkable Polyacrylate Binder for High-Performance Silicon Anodes in Lithium-Ion Batteries

High Resolution Image Download MS PowerPoint Slide Silicon (Si) is considered a promising anode material for next-generation lithium-ion batteries owing to its high theoretical capacity; however, its practical implementation is hindered by severe volume changes during cycling, leading to rapid capacity fading. Poly(acrylic acid) (PAA) is widely employed to stabilize Si anodes due to strong hydrogen bonding between its carboxyl groups and the Si surface, yet its stiffness and linear structure are insufficient to accommodate repeated deformation. In this study, we synthesize a blocked isocyanate-functionalized polyacrylate cross-linker (PAC) that is chemically compatible with PAA and enables latent cross-linking within the binder system. The incorporation of blocked isocyanate groups prevents premature cross-linking during copolymerization, while thermal deblocking during electrode drying induces covalent network formation with PAA. The elasticity of the resulting network is tuned through the butyl acrylate content in PAC, allowing effective stress accommodation during cycling. As a result, the Si anode employing the PAA/PAC binder delivers a high initial discharge capacity of 3418 mAh g –1 and retains 62% of its initial capacity after 300 cycles at 1 A g –1, outperforming the linear PAA electrode. These results demonstrate that a composition-tunable latent cross-linking strategy provides an effective design framework for mechanically robust and durable Si anodes.