Evolution of electrical degradation in ternary cathode materials of lithium-ion batteries

To understand the degradation mechanisms of lithium-ion battery (LIB) electrodes is highly necessary for the development of high-performance LIB electrode materials. Despite extensive studies on ternary cathode materials, insufficient studies have elucidated the mechanism of their electrical degradation. In this study, we perform scanning spreading resistance microscopy measurements to analyze the electrical degradation mechanism of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM) cathode materials. A step-like increase in resistance is observed in the degraded NCM cathode particles, as has been reported for degraded LiNi_0.8Co_0.15Al_0.05O₂ particles. In addition, a circular resistance increase distribution is observed in the initial degradation stage, which appears to be related to cracks formed from particle pulverization. Based on the resistance increase of various degraded NCM particles, we can propose a potential evolution pathway of electrical degradation in the NCM particles. This study offers meaningful insight into the degradation of ternary cathode materials, thereby providing valuable information for the development of high-performance LIB cathodes.