A robust network binder enables high-performance silicon anode via localized linking by small molecules

Abstract

The importance of network binder for improving cycling lifespan of silicon (Si) anode needs no further emphasis. However, the linear structure of natural polymer hardly creates a robust network binder. Herein, we propose a facile strategy of establishing a robust network binder by using small molecules of tartaric acid (TA) to locally link sodium carboxymethyl cellulose (CMC). Through hydrogen or covalent bonds, the resultant CMC-TA binder exhibits improved tensile and adhesive properties. The Si anode using CMC-TA binder delivers a satisfactory specific capacity of 2213 mAh g⁻¹ after 100 cycles at the rate of 0.2 C, with a capacity retention rate of 68.8%. This result has well confirmed the effectiveness of using small molecules to reinforce hydrogen-bonding linking between CMC and between Si particles for a high-performance Si anode.