Investigation on capacity decay of Li-rich LNMCO cathode material for lithium-ion batteries

The layered structure materials LiNi1-x-yCoxMnyO2 (0 < x, y < 1) (LNMCO) are the widely used cathode active materials for lithium ion batteries (LIBs). The potential method of getting high reversible capacity is to increase content of Ni element. However, high nickel cathode materials suffer from unfortunate cycling performance, which hinders their further commercialization. In this work, we report a systematic method to analyze attenuation process of high nickel cathode materials through specific capacity investigation and differential calculation of the charging curves. Combined with XRD measurement, we also identify that cationic disorder Ni2+ with Li+ was the essential reason for cathode attenuation. The modification of introducing extra Li+ in LNMCO lattices can reduce this cationic disorder. These findings regarding the decay mechanism as well as how extra Li element affects the reversibility and stability can provide a direction of preparing long cycling lifetime LNMCO materials and will promote their application in the future battery industry.