Nondestructive quantitative imaging for spatially nonuniform degradation in a commercial lithium-ion battery using a pulsed neutron beam

Abstract

A quantitative nondestructive Bragg-edge imaging technique for power-storage degradation was developed using commercial prismatic-shaped lithium-ion battery cells. The C or Li atoms/ions column density [cm−2] images for five phases of the negative electrode material (graphite, Li0.04C6, Li0.2C6, Li0.5C6, and Li1.0C6) with a 1 mm spatial resolution were obtained by considering the crystalline orientation for both fresh and fatigue cells. In the fresh cell, most of the graphite was uniformly converted to Li1.0C6 by charging, and in the fatigue cell, the graphite changed to various phases (especially, Li1.0C6 and Li0.5C6) by charging, and their spatial distributions were nonuniform.