Effect of MgF 2 Surface Modification for LiNi 0.8 Co 0.15 Al 0.05 O 2 Cathode Material on Improving Electrochemical Characteristics

Electrochemical characterization and thermal stability were investigated for MgF2 coated LiNi0.8Co0.15Al0.05O2 cathode. The ratio of MgF2 was controlled by 0.5, 1, 3 wt%. Cyclic voltammetty, charge-discharge profiles, rate capability, cycle life were measured for electrochemical properties. DSC analysis was measured for thermal stability. The first discharge capacities of MgF2 coated LiNi0.8Co0.15Al0.05O2 were decreased at 0.1C-rate compared to pristine LLiNi0.8Co0.15Al0.05O2. But the rate capability and cycle life of MgF2 coated LiNi0.8Co0.15Al0.05O2 were improved at 2C-rate. In DSC analysis result, the exothermic temperature of MgF2 coated LiNi0.8Co0.15Al0.05O2 was increased and peak height was decreased.