Highly Ion-Conductive Si Anode Binder with Optimized Tensile Strength and Large Deformation for Lithium-Ion Batteries

作者：Zhihao Zhang, Xingzhu Ma, Yanyun Li, Qiguang Liu, Feng Gao, Jue Cheng, Jiahao Ma, Junying Zhang · 发表于：ACS Applied Materials & Interfaces · 年份：2025 · DOI：10.1021/acsami.5c08295 · 被引用次数：13 · 研究领域：Advancements in Battery Materials、Graphene research and applications、Semiconductor materials and devices

Silicon (Si) anodes exhibit exceptional theoretical capacity but suffer from structural pulverization caused by dramatic volume changes derived from oxidation–reduction reactions during lithiation/delithiation cycles. Despite progress in binder development, integrating robust mechanical properties with high ionic conductivity in a single binder system remains a critical challenge due to the difficulty in optimal functional monomer sequence architecture. Herein, a PAA-based comb copolymer combining acrylic acid (AA), 2-carboxymethyl acrylate (CEA), and 3-sulfopropyl acrylate lithium salt (SPALi) was synthesized to be used as the Si anode binder. In the formulation, AA, CEA, and SPALi serve as rigid monomer, flexible monomer, and ion-conductive monomer, respectively, and the synergistic effect of the three functional monomers fulfills the integrated design of an ion-conductive rigid-flexible copolymer and thus enables the accommodation of external stress and high rate capacity of Si anodes. The ingenious combination of AA, CEA, and SPALi endows the binder with a tensile strength as high as 23.1 MPa, an elongation at break as high as 196.0%, and a high ionic conductivity reaching 5.7 × 10 –4 S cm –1 . The electrochemical performances of the Si anodes constructed with the p(AA- co -CEA- co -SPALi) binder are stabilized, and a retention capacity of 2120.4 mAh g –1 at 840 mA g –1 after 200 cycles together with a rate capacity of 1740.6 mAh g –1 at 2100 mA g –1 after 200 cycles is o...