Electrochemical properties of LiCoyMn2−yO4 synthesized using a combustion method in a voltage range of 3.5-5.0 V

LiCoyMn2−yO4 (y = 0.00, 0.04 and 0.08) were synthesized using a combustion method, and the electrochemical properties were examined in the voltage range of 3.5-5.0 V. The XRD patterns of the synthesized samples were similar, and the samples had a spinel phase structure. The first charge capacity curves exhibited an inflection in the voltage range of 4.2-5.0 V, where it is believed that additional, previously unreported phase transition occurs. The voltage vs. x curves for the first to fifth cycle exhibited two distinct voltage plateaus, corresponding well to a two-phase reaction and a one-phase reaction, respectively, as reported previously. For the voltage range of 3.5-5.0 V, the first discharge capacity increased and the cycling performance improved as y increased. Among these samples, LiCo0.08Mn1.92O4 had the largest first discharge capacity of 132.5 mA h/g at 600 μA/cm2, and its cycling efficiency was 91.1% at the 15th cycle in the voltage range of 3.5-5.0 V.