Li二次電池用正極材料LiMn系スピネルにおける電池特性の熱力学的検討

概要

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The relation between cathode performance and thermodynamic stability of lithium manganese spinels, LiMn_2O_4, Li_2Mn_4O_9, Li_4Mn_5O_<12> as cathode active materials for lithium secondary battery, has been investigated. The heat of dissolution of these samples was measured by the solution calorimetry method. The standard enthalpy of formation, Δ_fH^0, the enthalpy change of reaction, ΔH, and the enthalpy change per mole of atoms for the formation reaction, ΔH_R, were calculated from the heat of dissolution. |ΔH_R| decreased in order of Li_4Mn_5O_<12>> Li_2<Mn_4O_9>LiMn_2O_4, a larger |ΔH_R| meaning a thermodynamically more stable sample. In addition, lattice energies of these samples were calculated for a unit-cell. The trend order for lattice energies was the same as that for |ΔH_R|. A more thermodynamically stable sample makes a stable crystal structure and leads to a good cycle performance.
社団法人日本セラミックス協会の論文
2001-09-01