Surface Analysis of Composite Material for Lithium-ion Battery by means of Low Accelerating Voltage SEM-EDS

Abstract

The dispersed state of the conductive additives and the binders, which is a fluorine polymer, in the positive electrode material of the lithium ion battery electrode was evaluated by using an energy dispersive X-ray spectrometer attached to scanning electron microscope with a low accelerating voltage. By applying a low accelerating voltage, it is possible to reduce the penetration depth of electron beam into the target material and improve the energy resolution of light elements such as carbon and fluorine. Therefore, it was clarified that the dispersion state of the conductive additives and the binders around one particle of the active material could be observed as element distribution images, and the dispersion state could be quantitatively evaluated as the coverage by image processing. By estimating the coverage of conductive additives and binders on the surface of active materials depending on the dry mixing conditions, it was suggested that this technique could be used for structural design and process optimization of electrodes for improving battery performance.