Spiderweb-Like Binder with Ether Segments Shielding Silicon Anodes for Advanced Lithium-Ion Batteries

The huge volume expansion and poor electrical conductivity of silicon anodes have hindered their industrialization. In this study, a “topological adhesion” strategy was proposed to synthesize a polar ether-embedded poly(acrylic) binder for addressing these challenges. A block copolymer adhesive (PAC), composed of a backbone of flexible polyether chains and acrylic copolymers, as well as citric acid-grafted side chains, features ether segments that not only alleviate internal stress during the volume expansion of silicon (Si) but also form multiple synergistic Li+ transport pathways, thereby improving the electrochemical performance of the Si anode. The abundant polar groups further endow PAC with excellent interfacial adhesion to Si particles, offering superior stability and processability to the PAC-based slurry. With PAC as the binder, Si anodes achieve a higher initial Coulombic efficiency (90.6%) and markedly improved cycling performance (2462.4 mAh g–1 after 180 cycles at 0.2 C) compared to poly(acrylic acid) (PAA) as the binder (86.1%, 102.4 mAh g–1, respectively). Paired with LiNi0.8Co0.1Mn0.1O2 (NCM811), the full cell can stably charge/discharge for 100 cycles. These results demonstrate that our topology-engineered strategy is effective in enhancing the adhesion ability of the binder with Si and the current collector, as well as advancing the practical application of Si-based lithium-ion batteries.