Co-free 하이니켈 층상계 산화물 리튬 이차전지 양극재의 열화기작 연구의 최근 동향과 X선 기반 고도분석 기술의 활용

Elucidating degradation mechanisms of Co-free high-Ni layered oxide cathodes for Li-ion batteries via advanced X-ray-based characterization methods

High-Ni layered oxide cathodes without Co are being investigated as potential cathode materials for Liion batteries with high energy density. By decreasing the Co content, these cathodes not only boost energy density but also alleviate concerns about the supply instability and fluctuating cost of Co raw materials. However, the elevated Ni content in the layered oxides causes distinct chemo-mechanical degradation mechanisms that inhibit their commercial application. In order to gain insight into the degradation process at various scales, from the atomic to the particle and the electrode levels, and to devise ways to prevent degradation, multi-scale characterization methods are essential. In this review, we critically evaluate the role of Co substitution in high-Ni layered oxides and the impact of Co content on the chemo-mechanical degradation process. Furthermore, the use of advanced X-ray-based characterization methods, which have helped shed light on the degradation mechanisms of high-Ni cathodes, is also discussed.