A Web‐like Three‐dimensional Binder for Silicon Anode in Lithium‐ion Batteries

Si anode is of paramount importance for advanced energy‐dense lithium‐ion batteries (LIBs). However, the large volume change as well as stress generates during its lithiation‐delithiation process poses a great challenge to the long‐term cycling and hindering its application. Herein this work, a composite binder is prepared with a soft component, guar gum (GG), and a rigid linear polymer, anionic polyacrylamide (APAM). Rich hydroxy, carboxyl, and amide groups on the polymer chains not only enable intermolecular crosslinking to form a web‐like binder, A2G1, but also realize strong chemical binding as well as physical encapsulating to Si particles. The resultant electrode shows limited thickness change of merely 9% on lithiation and almost recovers its original thickness on delithiation. It demonstrates high reversible capacity of 2104.3 mAh g −1 after 100 cycles at a current density of 1800 mA g −1 , and in constant capacity (1000 mAh g −1 ) test, it also shows a long life of 392 cycles. Therefore, this soft‐hard combining web‐like binder illustrates its great potential in the future applications.