Unlocking the potential of silicon anodes in lithium-ion batteries: A claw-inspired binder with synergistic interface bonding

Binders play a crucial role in enhancing the cycling stability of silicon anodes in next-generation Li-ion batteries. However, traditional linear polymer binders have difficulty withstanding the volume expansion of silicon during cycling. Herein, inspired by the fact that animals' claws can grasp objects firmly, a claw-like taurine-grafted-poly(acrylic acid) binder (Tau-g-PAA) is designed to improve the electrochemical performance of silicon anodes. The synergistic effects of different polar groups (sulfo and carboxyl) in Tau-g-PAA facilitate the formation of multidimensional interactions with silicon nanoparticles and the diffusion of Li ions, thereby greatly improving the stability and rate performance of silicon anodes, which aligns with results from density functional theory (DFT) simulations. As expected, a Tau-g-PAA/Si electrode exhibits excellent cycling performance with a high specific capacity of 1003 mA h g−1 at 1 C (1 C = 4200 mA h g−1) after 300 cycles, and a high rate performance. The design strategy of using polar small molecule-grafted polymers to create claw-like structures could inspire the development of better binders for silicon-based anodes.