Influence of molecular structure of Carboxymethyl Cellulose on high performance silicon anode in lithium-ion batteries

Abstract

The study aims to the preparation of bio-based binders with optimal molecular structure for electrodes and the exploration of their influence on the electrochemical performance of electrodes. At first, a series of Carboxymethyl Cellulose (CMC) with different degree of polymerization (DP) and degree of substitution (DS) were successfully prepared using the specially designed method and their physical characteristics were also investigated. Si anodes were manufactured with the CMC binders and their electrochemical performances were evaluated and compared. As a consequence, the silicon anode containing CMC of DS= 0.38 and DP = 215 showed the best cyclic performance (71% of capacity maintained after the 100th cycle) due to its compatible molecular structure. It is assumed that the CMC with specially designed molecular structure plays a key role in binding the silicon particles during the cycles and weakened the volume effect.