Reducing defects in hard carbon graphite domain: Employing a fully dynamic bonding with a multi-crosslinked biomass-based binder for enhanced sodium ion storage

Binders are crucial for maintaining the integrity of an electrode and are confronted with the imperative for multifunctionality. Herein, we have developed and synthesized an entirely biomass-based water-soluble binder with outstanding adhesion, conductivity, flowability, and dispersibility for the hard carbon (HC) anode. Specifically, MXene (Ti 3 C 2 T x ) reduces the amount of HC graphite domain imperfections, the cross-linked carboxymethyl chitosan (CCS) chain facilitates Na + movement, and the amphiphilic nature of lignosulfonate (LS) enhances the distribution of active material. As a result, the HC anode achieves an initial coulombic efficiency (ICE) of 88 % and high-capacity retention of 110 % after 100 cycles. This work promotes the progress of green energy in parallel with the promotion of the high-value utilization of biomass.