Epoxy and amide crosslinked polarity enhanced polysaccharides binder for silicon anode in lithium-ion batteries

Highlights: • The high specific capacity of 1415 mAh g⁻¹ was obtained after 200 cycles at a current density of 0.2 C. • The lithium insertion capacity of the Si-KPG electrode was limited to 1000 mAh g⁻¹, which could maintain 650 cycles. • The Si-KPG electrode retained 75% of the initial capacity, compared with 33% of the Si-KGM electrode. -- Abstract: Natural polysaccharides are considered to be effective binders to enhance the cycle stability of silicon anode of lithium-ion batteries. However, the poor mechanical strength and relatively low binding strength have limited its further application. Epoxy and amide groups are recognized as the organic crosslinker with high polarity, which could bring qualified mechanical and binding strength. Herein, a crosslinked copolymer konjac glucomannan-g-polyacrylamide-g-glycidyl methacrylate (KPG) has been synthesized by radical polymerization reaction and applied as an aqueous binder for silicon anode materials. The introduction of polyacrylamide (PAM) and glycidyl methacrylate (GMA) improved the mechanical strength and binding strength through their high polarity and crosslinked effect. As a result, excellent electrochemical performance (capacity of 1415 mAh g⁻¹ after 200 cycles at 0.2 C) was obtained by using the crosslinked network binder. The lithium insertion capacity of the silicon electrode was limited to 1000 mAh g⁻¹, which can maintain 650 cycles. This reasonable design provides a way for the manufacture and practical application of high-performance silicon-based anodes.