In situ studies of Li_xMn₂O₄ and Li _xAl_0.17Mn_1.83O_3.97S_0.03 cathode by IMC

Thermal profiles of LiMn₂O₄ and LiAl _0.17Mn_1.23O_3.97S_0.03 were investigated with electrochemical-calorimetric technique. The beat contributions are discussed in terms of reversible and irreversible beat generation. The endothermic and endothermic beat profiles observed during the charge and discharge processes are related to the Li insertion/extraction reactions in the spinel host structure for both materials. The reversible heat generation is estimated on the basis of the cell entropy change. The heat generation calculated from ΔS and the open-circuit potential results are consistent with the heat profile (exothermic/endothermic) generated during the charge/discharge process and with the magnitude of the beat generation from the experimental results obtained from the isothermal microcalorimetry (IMC) at a slow charge/discharge rate. The irreversible heat generation dependence on the current is discussed at different discharge currents. The calculated results show good consistency with die experimental data.