2004 Volume 72 Issue 8 Pages 557-563
The spinel LiMn2-xNixO4 (x = 0~0.5) in which a part of Mn was substituted by Ni were prepared, and the Mn valence was determined by chemical analysis. Mn valence increased with increasing Ni content, x. The heats of dissolution of the samples were measured by the solution calorimetry method. The standard enthalpy of formation, ΔfH0, and the enthalpy change of reaction, ΔH, were calculated from the heat of dissolution. Thermodynamic stability was examined by ΔH. From the relation between the cathode performance and the thermodynamic stability of LiMn2-xNixO4 (x = 0~0.5), a more thermodynamically stable sample was found to lead to a good cycle performance.