Synthesis and electrochemical performance of Li_1+x(Fe_y/2 Ni_y/2Mn_1-y)_1-xO₂ cathode material

Li_1+x(Fe_y/2 Ni_y/2Mn_1-y)_1-xO₂ was synthesized by a coprecipitation-hydrothermal-calcinations method. The crystal structure and charge/discharge performance of Li_1+x(Fe_y/2 Ni_y/2Mn_1-y)_1-xO₂ were analyzed by X-ray diffraction (XRD), inductively coupled plasma (ICP) and electrochemical performance measurement. The XRD tests and ICP analyses demonstrate that Fe and Ni substitute a part of Mn of Li₂MnO₃ to form the good solid solution structure yLiFe_1/2 Ni_1/2O₂-(1-y)Li₂MnO₃ (y=0.1, 0.2, 0.3, 0.4, 0.5). SEM images show that different y values lead to different apparent morphologies of the materials. When y=0.4, the particles are spherical with uniform and small size. The electrochemical tests indicate that when y=0.4, the cathode material has the best electrochemical performance with the discharge capacity of 195.0 mAh/g after 50 cycles.