Design of multifunctional polymeric binders in silicon anodes for lithium-ion batteries

Silicon (Si) is a promising anode material for lithium-ion batteries (LIBs) owing to its tremendously high theoretical storage capacity (4200 mAh g(-1)), which has the potential to elevate the energy of LIBs. However, Si anodes exhibit severe volume change during lithiation/delithiation processes, resulting in anode pulverization and delamination with detrimental growth of solid electrolyte interface layers. As a result, the cycling stability of Si anodes is insufficient for commercialization in LIBs. Polymeric binders can play critical roles in Si anodes by affecting their cycling stability, although they occupy a small portion of the electrodes. This review introduces crucial factors influencing polymeric binders' properties and the electrochemical performance of Si anodes. In particular, we emphasize the structure-property relationships of binders in the context of molecular design strategy, functional groups, types of interactions, and functionalities of binders. Furthermore, binders with additional functionalities, such as electrical conductivity and self-healability, are extensively discussed, with an emphasis on the binder design principle.