The effect of samaria doped ceria coating on the performance of Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ cathode material for lithium-ion battery

The lithium-rich layered oxide; xLi₂MnO₃•(1-x)LiMeO₂ (Me = Co, Ni, Mn, etc.) is one of the most promising cathode materials for lithium-ion batteries in electric vehicles and energy storage systems due to its high energy density, low cost, and excellent thermal stability. In this work, Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ was synthesized and novel coating was applied to enhance the performance. The pristine Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ powder was synthesized by an aqueous solution method, followed by calcination at 900 °C in air, and the surface was then modified by coating with samaria doped ceria (SDC). Both the pristine and the surface modified materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and electrochemical measurements. The SDC coating with 1 wt.% was found to be the most effective in improving the discharge capacity. Specifically, it delivered 261 mAh g^-1 at 0.1 C rate with lower initial irreversible capacity loss. This superior electrochemical performance is attributed to the function of SDC as protective layer suppressing the side reaction between the electrode and the electrolyte, and decreasing the electron charge transfer resistance, as evidenced by the collected electrochemical impedance spectroscopy (EIS) data.