Stable Silicon Anodes Enabled by Innovative Biobased Binder with Cross-Linking Network in Lithium-Ion Batteries

Graphite anodes, with their capacity nearing the theoretical maximum of 372 mA h g^-1, are increasingly being complemented by silicon-based materials, which offer a 10-fold higher capacity. Nevertheless, extreme volume expansion (>300%) of Si during cycling poses significant challenges to its practical deployment. Previous studies on the synthesis of binders are often intricate and not conducive to large-scale implementation. In this study, an innovative binder, denoted as HM, is developed by combining the macromolecular polysaccharide sodium hyaluronate with the small organic molecule malic acid without the need for any external triggers. A cross-linked network structure is formed in situ after heat treatment with silicon under vacuum conditions. The contact interface establishes a robust network structure through multiple macromolecular hydrogen bonds and chemical interactions. Consequently, the HM binder exhibits exceptional mechanical properties and efficiently lessens the volumetric change of silicon particles, thereby benefiting the generation of a stable solid electrolyte interphase. Electrochemical characterization demonstrates that the exceptional cycling stability of Si@HM electrodes can maintain a high capacity of 1949 mA h g^-1 at 0.1 C and 1426 mA h g^-1 at 0.5 C after 100 cycles. Furthermore, silicon anodes employing the HM binder demonstrate superior rate performance and reduced internal resistance compared to those of conventional binders, representing a significant advancement in performance. This research provides crucial perspectives for binder design and experimental evidence for the commercial utilization of silicon anodes within lithium-ion batteries.