Hyperbranched β-Cyclodextrin polymer as an effective multidimensional binder for silicon anodes in lithium rechargeable batteries

Abstract

Polymeric binders play an important role in electrochemical performance of high capacity silicon (Si) anodes that usually suffer from severe capacity fading due to unparalleled volume change of Si during cy-cling. In an effort to find efficient polymeric binders that could mitigate such capacity fading, herein, we in-troduce polymerized β-cyclodextrin (β-CDp) binder for Si nanoparticle anodes. Unlike one-dimensional bind-ers, hyperbranched network structure of β-CDp presents multidimensional hydrogen bonding interactions with Si particles and therefore offers robust contacts between both components. Even the Si nanoparticles that lost the original contacts with the binder during cycling recover within the multidimensional binder network, thus creating a self-healing effect. Utilizing these advantageous features, β-CDp based Si electrode shows marked-ly improved cycling performance compared to those of other well-known binder cases, especially when com-bined with linear polymers at an appropriate ratio to form hybrid binders.