Epoxy Cross-Linking Enhanced the Toughness of Polysaccharides as a Silicon Anode Binder for Lithium-Ion Batteries.

The large volume expansion of a silicon anode induces serious mechanical failure and limits its applications. Owing to the intrinsic weak van der Waals force and poor toughness, it is unable to solve this issue with the current commercial poly(vinylidene difluoride) (PVDF) binder. The development of a binder with strong binding strength with silicon (Si) is urgent. Herein, a hydroxyl-rich three-dimensional (3D) network binder is synthesized by chemical cross-linking reactions between epichlorohydrin (ECH) and sodium hyaluronate (SH), which exhibits dramatically enhanced toughness and cohesive properties. The Si anode with the novel SH-ECH as the binder delivers excellent electrochemical performance, especially cycling stability. The discharge capacity could maintain 800.4 mAh g-1 after 1000 cycles at a current of 0.2 C with the average capacity decay rate per cycle of 0.015%. Our results pave a new way for the tailoring of the chemical structures of natural polymers to realize lithium-ion batteries (LIBs) with superior electrochemical performance.