Core-shell structure of polyacrylate-based binder enhancing the wet-adhesion strength and the kinetics of lithium-ion diffusion

Abstract

Despite constituting only a small fraction of the mass of an electrode, the binder is one of the key components ensuring the long-term durability of lithium-ion batteries (LIBs). The need for higher energy density and superior power characteristics necessitates the enhancement of the adhesion properties of the binder to reduce the binder contents of electrodes. In this study, we synthesized a core-shell structured poly(acrylonitrile-co‑butyl acrylate) binder that exhibits higher adhesion strength, lower kinetic resistance, and higher electrode and cell lithium-ion diffusion coefficients than those of styrene-butadiene rubber, which is widely used in commercial LIBs. The polystyrene (PS) constituting the core enhanced the electrical conductivity, while the lone pairs of electrons of poly(acrylonitrile-co‑butyl acrylate) expedited the lithium ion movement, thereby enhancing the kinetics of LIBs. The adhesion properties were enhanced in the presence of the carbonate-based liquid electrolyte owing to the carboxyl groups introduced by itaconic acid on the shells.