Suppressing the dry bed-lake fracture of silicon anode via dispersant modification in electrode processing
Fracture in silicon anodes is a commonly fundamental problem, which results in ca. 80% capacity loss over the electrochemical cycles. Alginate, as one of many water-soluble polysaccharides, are efficient binder systems for silicon (Si) electrode due to their strong interface bonding with Si surface. However, the rigidness and brittleness of the polysaccharides induce dense fracture on the Si anode. In this work, a facile and effective physical approach is proposed by introducing glycerol as the plasticizer in the electrode processing. Glycerol contributes to an improvement of the ductility and flexibility of the binder, which effectively alleviates the fracture formation and propagation during repeated electrochemical cycles. At the optimum alginate/glycerol weight ratio of 2:1, silicon anode displays much improved electrochemical performances in terms of the long-term cycling performance and the rate capability. The well-preserved physical integrity of the Si anode after long-term cycles explains the electrochemical enhancement. The facile and effective dispersant optimization in electrode processing provides a new avenue for Si electrode fabrication with high electrochemical performances.