Natural sesbania gum as an efficient biopolymer binder for high-performance Si-based anodes in lithium-ion batteries

Polymer binder plays a significant part in boosting the electrochemical performance of Si-based anode for Li-ion batteries. In this study, the natural sesbania gum (SG) as an efficient biopolymer binder is firstly applied on the silicon nano-particles (SiNPs) anode and the commercial SiOx/C composite anode of Li-ion batteries. SG with branched structure and numerous polar groups exhibits high mechanical properties, remarkable interfacial adhesion and powerful cohesion. The Si @ SG electrode delivers a high initial Coulombic efficiency (ICE) of 90.92% and holds a superior reversible capacity of 2023 mAh g(-1) at 1000 mA g(-1) for 120 cycles. In addition, the Si electrode based on less SG and higher SiNPs loading (1.30 mg cm(-2)) can maintain a satisfactory reversible capacity of 1621.1 mAh g(-1) under 1000 mA g(-1) for 100 cycles. When expended to the commercial SiOx/C composite anode, SG matched with the solution-type LA136D binder (consisting of acrylic acid derivative multipolymer) presents excellent synergistic effect. All of the SiOx/C composite electrodes exhibit favorable cycling performance and high capacity retention over 92% at 1C rate after 100 cycles. This study demonstrates that SG provides a prospective avenue to pursue the enhanced cycling longevity of Si-based anodes for Li-ion batteries.