In this study, isothermal micro-calorimetry is used to examine the heat generation of lithium- and manganese-rich layered oxides (LMR-NCMs) during their first cycle. LMR-NCM exhibits a voltage hysteresis and a unique voltage plateau at ≈4.5 V during the first charge, leading to irreversible structural rearrangements and significant heat generation. The results indicate that the activation process and the extent of overlithiation directly influence the heat generated during the first discharge, which plays a crucial role in the low energy efficiency of LMR-NCMs.
Heat Generation during the First Activation Cycle of Li-Ion Batteries with Li- and Mn-Rich Layered Oxides Measured by Isothermal Micro-Calorimetry / Friedrich, F.; Kunz, A.; Jossen, A.; Gasteiger, H. A. / J. Electrochem. Soc. 2023, 170, 050506 (Open Access) - DOI