An Self-Healing Effective Binder for Silicon Anodes in Lithium Ion Batteries

Abstract

Unexpected electrochemical performance of the high-capacity silicon (Si) anode materials has been shown, due to severe capacity fading caused by enormous substantial volume change of Si during cycling. In an effort to find efficient polymer binder that could mitigate such capacity fading, alginate-carboxymethyl chitosan(Alg-C-chitosan) composite polymer is investigated as a low-cost water soluble binder for silicon anodes in lithium-ion batteries. The electrostatic interaction between carboxylate(-COO-) of Alg and protonated amines(-NH3+) of C-chitosan leads to the formation of a self-healing porous scaffold structure. Synergistic effect on the enhanced porous scaffold structure and self-healing electrostatic interaction of Alg-C-chitosan binder, effectively tolerate the tremendous volume change of Si and maintain an integrated electrode structure during cycling process. The Si nanopowder electrodes with Alg-C-chitosan composite binder exhibit an excellent cycling stability, with a capacity of 750 mAh g-1 remaining after 100 cycles. In addition, an extraordinary areal capacity of 3.76mAh cm-2 is achieved for Si-based anodes with Alg-C-chitosan binder.