In Situ Construction of SiO Anodes with Enhanced Hydrogen Bonding via Progressive Hydrolysis-Released Carboxyl Groups...

Binder engineering provides a powerful solution for the fabrication of long-life silicon monoxide (SiO) anodes. Conventional aqueous binders rely on reversible hydrogen bonds between polar functional groups (e.g., ─COOH) and the SiO surface for adhesion. However, due to the inherently weak and short-range nature of hydrogen bonds, strong adhesion requires their accumulation. In practice, the effective utilization of these groups is significantly limited by self-association or cation interference (e.g., Na⁺). Herein, the study reports a novel-concept binder, poly(ethylene-alt-maleic anhydride) (P(EAMA)), which progressively releases carboxyl functional groups through stepwise hydrolysis and in situ forms high-density hydrogen bonds with the SiO surface. This strategy effectively suppresses the self-association of carboxyl groups, maximizing their utilization for hydrogen-bond formation. The resulting poly(ethylene-alt-maleic acid)/SiO (P(EAM)/SiO) electrodes, benefiting from abundant hydrogen bonds and the intrinsic resilience of the P(EAM) network structure, demonstrate exceptional mechanical strength and flexibility. These electrodes exhibit superior cycling stability (856.2 mA h g^-1 after 350 cycles at 2 A g^-1) and full-cell compatibility (91.2% capacity retention after 100 cycles), outperforming electrodes prepared with conventional alginate binder or fully hydrolyzed P(EAMA). The proposed binder, enabling sustained functional group release for robust adhesion, is expected to significantly advance the practical application of various Si-based anodes.