Study on Mechanical Fatigue Properties of Polymer Binder in Electrode Material for Lithium-ion Battery

Abstract

The electrode materials for lithium-ion batteries are microscopically connected by a polymeric binder that does not affect the electrolytic reaction of the active material in powder form. In this study, tensile fatigue test and plane bending fatigue test were conducted on electrode materials fabricated with various binder concentrations to investigate the mechanical fatigue properties of the binders that support the structure of the electrode materials. A mechanical model approximating the microscopic structure of the electrode material proposed in this study was used to estimate the fatigue properties of the binder. From the results of the tensile fatigue test, it was found that the binder causes energy dissipation and superposition, which leads to macroscopic fracture of the electrode material. The S–N curves of the specimens with low binder concentration predicted based on the results of the tensile fatigue test were safe evaluation against the results of the plane bending fatigue test.