A New High Power LiNi0.81Co0.1Al0.09O2 Cathode Material for Lithium-Ion Batteries

Abstract

Among the various Ni-based layered oxide systems in the form of LiNi1-y-zCoyAlzO2 (NCA), the compostions between y = 0.1-0.15, z = 0.05 are the most successful and commercialized cathodes used in electric vehicles (EVs) and hybrid electric vehicles (HEVs). However, tremendous research effort has been dedicted to searching for better composition in NCA systems to overcome the limitations of these cathodes, particularly those that arise when they are used use at high discharge/charge rates (>5C) and in high temperature (60 °C) environments. In addition, improving the thermal stability at 4.5 V is also very important in terms of the total amount of heat generated and the onset temperature. Here, a new NCA composition in the form of LiNi0.81Co0.1Al0.09O2 (y = 0.1, z = 0.09) is reported for the first time. Compared to the LiNi0.85Co0.1Al0.05O2 cathode, LiNi0.81Co0.1Al0.09O2 exhibits an excellent rate capability of 155 mAh g-1 at 10 C with a cut-off voltage range between 3 and 4.5 V, corresponding to 562 Wh kg-1 at 24 °C. It additionally provides significantly improved thermal stability and electrochemical performance at the high temperature of 60 °C, with a discharge capacity of 122 mAh g-1 after 200 cycles with capacity retention of 59%.