A Fast Self-Healing Binder for Highly Stable SiO_x Anodes in Lithium-Ion Batteries

Silicon oxide-based (SiO_x-based) materials show great promise as anodes for high-energy lithium-ion batteries due to their high specific capacity. However, their practical application is hindered by the inevitable volumetric expansion during the lithiation/delithiation process. Constructing high-performance binders for SiO_x-based anodes has been regarded as an efficient strategy to mitigate their volume expansion and preserve structural integrity. In this work, we propose a green water-solution PAA-LS binder composed of poly(acrylic acid) (PAA) and sodium lignosulfonate (LS) with fast self-healing properties. The designed binder can be restored due to the strong affinity between Fe³⁺-catechol coordination bonds, thereby effectively alleviating the volumetric strain of SiO_x-based anodes. Notably, with an optimized LS content of 0.5%, the SiO_x@PAA-LS electrode exhibits excellent performance, delivering a high capacity of 997.3 mAh g^-1 after 450 cycles at 0.5 A g^-1. Furthermore, the SiO_x||NCM622 full cell also demonstrates superior cycling stability, maintaining a discharge capacity of 147.58 mAh g^-1 after 100 cycles at 0.5 A g^-1, with an impressive capacity retention rate of 82.72%.