Ni-Rich Co-less Cathode Materials with LiYO2 and Y3+ Modification Toward Improved Storage Performance against Ambient Air for Lithium-Ion Batteries

Despite many advantages of Ni-rich Co-less cathode materials (Ni ≥ 90%), further applications of such materials are limited by the extreme sensitivity to the air environment. Herein, cathode material with the optimal amount of yttrium modification is selected for comparison with the bare NCM. The differences of various physicochemical indexes between the two materials before and after exposure to air environment treatment are evaluated comprehensively by various characterization methods, such as XPS, SEM, EDS, XRD, HRTEM, EIS, etc. Impressively, the formation of undesirable residual lithium compounds was significantly suppressed due to the effective protection of the LiYO2-coated nanolayer and the doping of Y3+, which prolonged the lifetime of environmental storage. In addition, the Y2-NCM cathode maintained good cycling stability and low impedance after 4 weeks of exposure to ambient air. This work provides a method to reduce the air sensitivity of Ni-rich, Co-less cathode materials.