Electrochemical Characteristics of LiMn₂O₄ (Li/Ni) Cathode Materials

Abstract

The present study used the Pechini process with a continuous furnace to synthesize LiMn₂O₄ powders. After heat treatment, the particle size and lattice constant of the LiMn₂O₄ powder increased. For heat treatment cathode powders (LMO800), due to both the average valence of Mn cations approaching the theoretical value and the higher crystalinity, the discharge capacities are raised significantly. The charge and discharge cycling capacity of LMO800 powder was best at 25°C. Under the charge-discharge cycling test at 55°C, some Mn ions dissolved easily into the electrolyte resulting in a significant decrease in the charge and discharge capacity with increasing the cycling number. The surface modification powder (LMO-Ni) contains a surface oxidative film of lithium-nickel-manganese that not only restrains Mn ions dissolved into the electrolyte, but also improves the charge and discharge capacity at 55°C.