Electrochemical properties of LiCoyMn2−yO4 synthesized by the combustion method for lithium secondary battery

LiCoyMn2−yO4 (y=0.00, 0.04 and 0.08) were synthesized by the combustion method and the electrochemical properties are examined. The sample for y=0.00 has the largest first discharge capacity (125.3 mA h/g). The cycling performance improves as y increases. The sample with y=0.08 has the first discharge capacity 118.8 mA h/g and the discharge capacity at the 100th cycle 95.0 mA h/g. The decrease in the length of the higher-voltage plateau (around 4.07 V) with cycling has a strong influence on the decrease in the cycling performance. The better crystallinity, the larger lattice parameter, and the finer and more homogeneous particles of LiCoyMn2−yO4 by the combustion method, compared with those for LiMn2O4 by the solid-state method, are considered to lead to the larger discharge capacities.