Self-healing polymer binders for the Si and Si/carbon anodes of lithium-ion batteries

A silicon anode with a high specific capacity is one of the most promising candidates for developing advanced rechargeable lithium-ion batteries (LIBs). However, the problems of low electrical conductivity, severe volume changes during use and an unstable solid electrolyte interface seriously hinder their use in LIBs. Although using the carbon materials used to construct Si/C composite anodes have demonstrated their advantages in improving the performance of Si-based anodes, the binder, another key component of the electrode, also has a significant effect on the electrochemical performance of a battery. A self-healing binder uses non-covalent and reversible covalent bonds to effectively improve the cycling stability of LIBs by repairing the internal/external damage caused by the huge volume change of a Si-based anode. As for the solid-state polymer electrolytes (SPEs) of flexible lithium batteries, the use of self-healing polymers can also quickly repair the damages or cracks in the SPEs, and have a promising prospect in the development of flexible and wearable electronics. The paper gives an overview of the synthesis, characterization and self-healing mechanisms of the self-healing polymer binders for use in Si and Si/C anodes and their recent application in flexible lithium batteries is briefly summarized. The related technical challenges and design requirements for self-healing polymer binders used in the Si and Si/C anodes of LIBs are discussed.