Enhanced electrochemical properties of sodium-doped lithium-rich manganese-based cathode materials

In this work, sodium has been successfully doped into the layered lithium-rich manganese-based cathode material through melt impregnation. The as-prepared samples are characterized by multiple techniques of x-ray diffraction, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy and the electrochemical measurements. The results show that sodium doping hardly changes the layered structure and surface morphology of pristine sample. The sample particles of sodium-doped materials exhibit polygonal shape similar to prism. The sodium-doped material possesses high rate performance and good cycling stability, and the initial charge and discharge capacity reaches 340.2 mA h g^?1 and 249.0 mA h g^?1 at a current density of 20 mA g^?1, respectively. The initial coulombic efficiency of the first cycle is 73 %. After running 100 repeated cycles at 40 mA g^?1 and 100 mA g^?1, the discharge capacity could still be maintained at about 230.0 mA h g^?1 and 220.0 mA h g^?1, respectively. Moreover, the voltage attenuation is effectively suppressed during charging/discharging cycles.