Improving the electrochemical performance of Li2MnO3 cathode material by micro-substitution of nickel to manganese

A new orientation of replacing Mn with Ni by sol-gel method to improve the electrochemical performance of Li2MnO3 is proposed. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses reveal that the Ni element is distributed in the sample evenly. The Ni-LMO sample exhibits a great improvement on the rate capability and practical capacity compared with the LMO sample. Specimen Li2Ni0.03Mn0.985O3 delivers an initial discharge capacity of 174.6 mA h g−1 with an excellent capacity of 234.2 mA h g−1 after 10 cycles at 0.1 C, and 198.1 mA h g−1 with a capacity retention of 96.8% after 50 cycles. The CV curve indicates that Ni doped will prevent the first cycle from layer to spinel phase and inhibiting the rate of transition during cycling. Electrochemical impedance spectroscopy (EIS) results confirmed that Ni doped reduced the charge-transfer resistance and improved the electrochemical reaction kinetics.