Thermodynamic study and transition metal (nickel) doping on Li_1.2Mn_0.8O₂ as a cathode material

Materials Modelling Centre, University of Limpopo, Private Bag x1106, Sovenga, 0727, South Africa

^* mikosivusi@gmail.com

Abstract

Several studies have been conducted to overcome the poor cycling stability, voltage fade, and low coulombic efficiency barriers in practical applications of Lithium manganese oxides. Transition metal doping is considered as one of the effective techniques to enhance the stability of these materials. In this study we use the genetic algorithm within cluster expansion to generate new phases of Ni-doped Li_1.2Mn_0.8O₂ which was constructed from Li₂MnO₃. Li₂MnO₃’s high energy density and high specific capacity have drawn attention to the material as a promising cathode for lithium-ion batteries. The generated phases are thermodynamically stable with negative heats of formation. Furthermore, first principles calculations were performed to study the thermodynamic, mechanical, and electronic properties of these materials. The materials were found to be thermodynamically stable with negative heats of formation and mechanically stable under the strain 0.001. Furthermore, the generated phases show an improvement on the conductivity of the Li_1.2Mn_0.8O₂ since they do not have band gaps suggesting that they are conductors.