Binder Selection and Stress Tuning in Silicon Anodes for Lithium-Ion Batteries Under Mechanochemical Coupling

Silicon-based anode materials have garnered significant attention due to their exceptionally high theoretical specific capacity ([Formula: see text] mAh/g). However, their considerable volume expansion often leads to stress concentration and structural failure, which degrades battery performance. To address this critical challenge, recent research has increasingly focused on tuning binders to mitigate stress in silicon anodes. Despite these efforts, most studies have examined individual binders in isolation, lacking a comprehensive comparative analysis. In this study, multiphysics simulations are used to systematically compare the effects of three binders: polyacrylic acid (PAA), polyvinylidene fluoride (PVDF), and polyvinyl alcohol (PVA) on stress distribution at the silicon particle–binder interface under mechanochemical coupling conditions. The results reveal that the PAA binder demonstrates superior performance in reducing stress concentration and enhancing structural stability. Building on these findings, we further investigate the effects of charging rates, as well as the thickness and surface coverage of the PAA binder in relation to the mechanical integrity of the electrode, and propose a corresponding strategy for binder optimization. This study provides new theoretical insights into the selection and tuning of binders in lithium-ion batteries, offering the potential to significantly improve battery lifespan and performance.