A Modified Natural Polysaccharide as a High-Performance Binder for Silicon Anodes in Lithium-Ion Batteries

A modified natural polysaccharide (carboxymethylated gellan gum) is investigated as a water-soluble high-performance binder for silicon anodes in lithium-ion batteries to improve poor cycle life and fast capacity fade of silicon anodes due to dramatic volume expansion during lithiation/delithiation process. The numberof carboxyl and acetyl groups distributed homogeneously in the modified polysaccharide polymer chain can form strong hydrogen bonds with the surface of Si particle and copper current collector, thus effectively restricting the volume change of silicon and maintaining electronic integrity of Si electrodes during repeated charge/discharge cycles. As a result, Si anodes with carboxymethylated natural polysaccharide polymer present high capacity performance, excellent rate capability, and stable cycling.