Decreasing the initial irreversible capacity loss of graphite negative electrode by alkali-addition

The effect of alkali function group contained in electrode binder was investigated. Carboxy methyl cellulose (CMC) improved the initial irreversible capacity loss in graphite negative electrode. Lithium acetate also improved the initial cycle efficiency. On the other hand, ethyl cellulose (EC) and hydroxyl propyl methyl cellulose (HPMC), which do not have a carboxylic group, did not decrease the reductive electrolyte decomposition. After charge and discharge cycle, the surface film composition on the electrode with CMC was less than on the electrode without CMC. This suggests that a carboxylic group in the binder acted as a catalyst and promoted the solid electrolyte interphase (SEI) formation which prevents the excess electrolyte decomposition on the graphite electrode.