Preparation and Electrochemical Properties Studies of Al-doped LiNi _0.8Co_0.2O₂ Cathode Materials

Al-doped LiAl_γNi_0.8-γCo _0.2O₂(γ = 0.001, 0.005, 0.01, 0.03) cathode materials were synthesized by the solid-state method. The materials were characterized by XRD, SEM, ICP-AES, differential chronopotentiometry and galvanostatic cycling. The results showed that the products, without impurities, had typical α-NaFeO₂ layered structures, uniform morphology and moderate grain size. The discharge voltage plateau as well as discharge capacity of the Al-doped materials was higher than that of the undoped ones. And with the amount of Al increasing to a certain extent, the structure stability of the materials was improved during the charge-discharge process. Therefore the electrochemical stability was improved. The results also indicated that low Al-dopant could not only improve the cyclability but also gain high discharge capacity.