Partially Neutralized Polyacrylic Acid as an Efficient Binder for Aqueous Ceramic‐Coated Separators for Lithium‐Ion Batteries

Abstract

AbstractA partially neutralized polyacrylic acid (Pn−PAA) is used for coating sub‐micron‐sized α‐alumina on a conventional microporous polyolefin separator, fabricating a ceramic‐coated separator (CCS). Pn−PAA acts as a dispersant and binder by adsorbing itself on alpha(α)‐alumina surfaces under acidic condition through the columbic interaction, providing a repulsive force to disperse fine alumina in aqueous suspension, and binds alumina strongly on plasma‐treated separator through hydrogen bonding. This CCS shows favorable wettability in carbonate‐based liquid electrolyte and ionic conduction due to the high hydrophilicity of Pn−PAA and alumina. With that, this study found that Pn−PAA‐made‐CCS yields a substantial adhesion strength of ~106 N/m with enhanced cycle stability, a specific capacity of 145.0 mAh/g after 200 cycles at 1 C at room temperature in half cells (LFP/Li metal).