Research Progress of Polyacrylate Binders for Silicon-Based Anodes in Lithium-Ion Batteries

Silicon (Si) has emerged as a preeminent candidate for next-generation lithium-ion batteries (LIBs) anodes, primarily attributed to its exceptionally high specific capacity. Nevertheless, the substantial volumetric expansion accompanying lithium alloying reactions has long posed a critical challenge to the commercial viability of silicon-based anodes. Binders as connectors between the active Si particles, conductive agents, and current collectors, playing a crucial role in stabilizing the structure of silicon anodes in LIBs. Polyacrylic acid (PAA) water-based binders contain abundant carboxyl groups (─COOH) that can enhance adhesive strength. However, simple linear PAA does not adequately accommodate the significant volume expansion of silicon anodes. To address this issue, various structural optimization strategies have been applied to modify PAA binders. In this context, a comprehensive review is conducted on the recently developed PAA-based binders, which cover linear, branched, and 3D network configurations. A meticulous comparison is carried out regarding their initial coulombic efficiency, areal capacity, and material costs. Moreover, in-depth insights are offered to elucidate the mechanisms by which these structural modifications augment the properties of the binders and the performance of the cells. Ultimately, the prospective directions for the evolution of PAA-based binders designed for Si-based anodes in high-energy-density LIBs are deliberated.