Polyethylene Imine Crosslinked Sodium Alginate Binder for Micro-Silicon/Graphite Composite Anodes

Abstract

Commercialization of silicon anodes remains a challenge due to severe volume changes during cycling. In this study, a novel binder was synthesized via in situ crosslinking of sodium alginate (NaA) and poly(ethylene imine) (PEI) and used in micro-silicon/graphite composite anodes. Ball milled silicon possesses an increased hydrophilic character, which leads to poor compatibility with graphite in composite anodes using a standard NaA binder. However, the addition of PEI to NaA led to an increase in the specific capacity of ∼1000 mAh/gSi, which can be traced back to the increased compatibility between silicon and graphite induced by a crosslinked binder structure.