Enhanced cycling stability and rate capability of silicon/graphite anodes by chitosan-based aqueous binder

Si/Gr anodes have high specific capacity but their cycle stability is not ideal due to excessive volume expansion during discharge/charge cycling, thereby limiting the commercialization of lithium-ion batteries (LIBs). In this paper, a chitosan-polyvinyl alcohol (CS-PVA) water-based binder was prepared. Unlike conventional one-dimensional structural adhesives, CS-PVA adhesives are rich in hydroxyl and amino polar groups. The polar groups induced interactions with Si–OH on silicon particles, further enhancing the structural stability of Si/Gr anode to maintain long-term stable cycling of LIBs. In addition, the Si/Gr anode formed a stable solid electrolyte interface (SEI) during the activation process, leading to long-term stable cycling Si/Gr anodes. The first Coulomb efficiency of Si/Gr@PC11 anode reached 85.5%. And at the current density of 0.5C, the discharge capacity stabilized at 505mAh g −1 after 200 cycles, and reached 433mAh g −1 after 500 cycles. In summary, the success of this work provides a promising avenue to develop high-capacity lithium battery packs with extended cycle life.