Vulcanized polyisoprene-graft-maleic anhydride as an efficient binder for silicon anodes in lithium-ion batteries

Vulcanized polyisoprene-graft-maleic anhydride (VPI-g-MA) has been utilized as an in situ cross-linked binder for silicon (Si) anodes. PI-g-MA was vulcanized with sulfur at 180 °C to form an elastic polymer with a glass transition temperature of −45.5 °C measured via differential scanning calorimetry. The results of infrared spectroscopy confirm the formation of C-S bonds. The Si anode with the VPI-g-MA binder exhibited a high initial charge capacity of 4005 mAh g−1 at a charge/discharge rate of 0.1 C and demonstrated significant cycle-life performance of up to 200 cycles at a C-rate of 0.5 C. Furthermore, the peeling test results showed that the Si electrode with the VPI-g-MA binder has better adhesion strength than the Si electrode with either PVDF, PI-g-MA, or SBR/CMC binder. Scanning electron microscopy images showed that the VPI-g-MA binder could effectively maintain the integrity of the Si electrode throughout the cycling process. Thus, the VPI-g-MA binder can enhance the cycle-life performance of Si anodes.