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.