Stabilizing the surface of LiNi_0.815Co_0.15Al_0.035O₂ by a facile pre-oxidation-coating strategy on the precursor

Ni-rich layered LiNi_0.815Co_0.15Al_0.035O₂ cathode material is stabilized by a facile oxidation-coating strategy on the hydroxide precursor Ni_0.815Co_0.15Al_0.035(OH)₂. Potassium permanganate is employed as both oxidizing agent and manganese source for the Mn-containing coating layer on the precursor. X-ray diffraction and scanning electron microscopy reveal that the surface modification does not alter the crystallographic structure and particle morphology of the layered cathode. Energy dispersive spectrometry confirms the uniform distribution of manganese on the modified cathode materials. X-ray photoelectron spectroscopy demonstrates that the oxidation-coating strategy gives rise to a relatively higher content of Ni³⁺ in the cathode, thereby suppressing the cation mixing. Electrochemical characterizations reveal that the oxidation-coating strategy on the precursor improves the cycling performance at both room temperature and elevated temperature, as well as the moisture resistance in the air.