Preparation and Electrochemical Properties Studies of Al-doped LiNi_(0.8)Co_(0.2)O_2 Cathode Materials

Al doped LiAlyNi0.8-yCo0.2O2(y=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.