Self-Substitution and the Temperature Effects on the Electrochemical Performance in the High Voltage Cathode System LiMn_1.5+xNi_0.5−xO₄ (x = 0.1)

The high voltage cathode material, LiMn_1.6Ni_0.4O₄, was prepared by a polymer-assisted method. The novelty of this work is the substitution of Ni with Mn, which already exists in the crystal structure instead of other isovalent metal ion dopants which would result in capacity loss. The electrochemical performance testing including stability and rate capability was evaluated. The temperature was found to impose a change on the valence and structure of the cathode materials. Specifically, manganese tends to be reduced at a high temperature of 800 °C and leads to structural changes. The manganese substituted LiMn_1.5Ni_0.5O₄ (LMN) has proved to be a good candidate material for Li-ion battery cathodes displaying good rate capability and capacity retention. The cathode materials processed at 550 °C showed a stable performance with negligible capacity loss for 400 cycles.