Core-Shell Binder for High-Density Battery Electrodes

The binder particle is segmented into a core-shell structure where the core portion provides swelling for ion conductivity and the shell portion provides binding capacity. This segmentation allows each part to optimize its function independently, resolving the contradiction between ion conductivity and electrode capacity.

Different regions of the binder particle have different properties: the core portion has high swelling ratio for ion conductivity while the shell portion has appropriate glass transition temperature for binding. This local differentiation of properties allows simultaneous achievement of ion conductivity and electrode capacity.

The core-shell structure segments the binder functions so that the core's high swelling ratio maintains ion conductivity channels open even at high density, enabling fast ion transport and thus improving rate characteristics while maintaining electrode capacity.

By changing the physical parameters of the binder (core swelling ratio and shell glass transition temperature), the electrode maintains both high capacity and fast reaction kinetics, resolving the contradiction between capacity and rate characteristics.

The core-shell structure separates the swelling function (core) from the binding function (shell), allowing the shell to maintain strong adhesion during cycling while the core ensures ion conductivity, thus improving cycle characteristics without sacrificing capacity.

The shell portion with controlled glass transition temperature provides localized mechanical stability and adhesion during expansion/contraction cycles, while the core provides localized ion conductivity, together resolving the contradiction between capacity and cycle life.