Polymer Binders for High-Performance Lithium-Ion Batteries

Abstract

Polymer binders play a critical role in lithium-ion battery electrodes by providing mechanical cohesion among active materials, conductive additives and current collectors. They help to preserve the structural integrity of the composite and sustain continuous electron/ion migration pathway throughout repeated lithiation-delithiation cycling. Despite their essential role, polymer binders have historically been understudied, and only limited commercial ones, such as polyvinylidene fluoride (PVDF), carboxyl methylcellulose (CMC)/styrene-butadiene rubber (SBR) and polyacrylic acid (PAA), have been adopted. These widely used commercial binders have intrinsic drawbacks including insufficient adhesion, mechanical brittleness, swelling propensity and using toxic solvents, making them inadequate for high-energy-density batteries. This review categorizes binder design strategies according to the specific requirement of various cathode materials and anode materials, with a particular emphasis on those employed in commercial electrodes as well as those reported in academic research. Finally, perspectives on future binders for high-energy-density batteries with extended cycling life and sustainability are presented.