Electrochemical performance of polysaccharides modified by the introduction of SO3H as binder for high-powered Li4Ti5O12 anodes in lithium-ion batteries

Abstract

Abstract Much attention has been paid to various polysaccharides as potential binder candidates for lithium-ion batteries, due to their strong adhesion through numerous hydroxyl and carboxyl functional groups, and water soluble characteristic. In contrast, the improvement of lithium ion transport of polysaccharide binders has hardly been addressed. For this purpose, the traditional sodium alginate (Alg) and carboxymethyl cellulose (CMC) binders are sulfonated to introduce sulfo functional groups (SO3H) to the backbone of the polysaccharides. The sulfonation increases the ionic conductivity of the polysaccharide by at least 2 mS/cm, compared to that of unsulfonated polysaccharides in a solution state. The increase enhances the cyclic performance of Li4Ti5O12 (LTO) electrodes. For example, the sulfonated CMC-containing LTO electrode shows 153.2 mAh g−1 at the 100th cycle, whereas the unsulfonated CMC-containing LTO electrode shows 117.6 mAh g−1. As the charge/discharge current rates increase, the difference becomes more significant. In addition, various characterizations demonstrate that when used as LIB binder, the sulfonated polysaccharides own superior electrochemical properties.