Abstract: The effects of cell temperature on the rate discharge capability, lithium ion diffusion rate and charge transfer activity of LiNi3/8Co2/8Mn3/8O2 were investigated by using X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS), constant-current charge-discharge test, cyclic voltammetry and electrochemical impedance spectroscopy(EIS). The experimental data show that the rate discharge capability of LiNi3/8Co2/8Mn3/8O2 is improved by increasing cell temperature. Both the charge transfer activity and the lithium ion diffusion rate in LiNi3/8Co2/8Mn3/8O2 increase at elevated temperatures. The activation energy for charge transfer is more than twice that for the lithium ion diffusion. The results indicate that the electrochemical reaction kinetics of LiNi3/8Co2/8Mn3/8O2 is mainly limited by charge transfer process. The charge transfer process is more affected by temperature than the lithium diffusion process. Improvement of the rate discharge capability of LiNi3/8Co2/8Mn3/8O2 at elevated temperatures is mainly caused by the increase of charge transfer rate in LiNi3/8Co2/8Mn3/8O2.

Key words: LiNi_3/8Co_2/8Mn_3/8O₂, Cell temperature, Electrochemical property, Lithium-ion battery