Lithium ion batteries are potential energy source of electric vehicles (EVs).However, problems such as safety, durability, low capacity, cycle life etc. restrict their use in EVs. These problems mostly related with cathode materials, an improvement in cathode materials cause significant changes inbattery performance. In this work, Al2O3 coating on LiNi0,5Mn0,3Co0,2O2 cathode material produced by sol – gel method. The surface modification of LiNi0,5Mn0,3Co0,2O2 was started by adding LiNi0,5Mn0,3Co0,2O2 powders into alumina sol. Then, sonication was started and three different sonication powers were tested (15%, 30%,45%). X – ray diffraction (XRD) measurements showed that the material had a well – ordered layered structure and Al was not in the LiNi0,5Mn0,3Co0,2O2. Al2O3 coated materials show better cycling performance compared to the pristine material. It is believed that, this improvement is caused by the fact that Al2O3 layer prevents direct contact between active material and electrolyte and reducing the decomposition reactions.