Insights from Ab Initio Molecular Dynamics on the Interface Reaction between Electrolyte and Li₂MnO₃ Cathode during...

The complex interface reactions are crucial to the performance of the Li₂MnO₃ cathode material. Here, the interface reactions between the liquid electrolyte and the typical surfaces of Li₂MnO₃ during the charging process are systematically investigated by ab initio molecular dynamics (AIMD) simulation and first-principles calculation. The results indicate that these interface reactions lead to the formation of hydroxide radicals, oxygen, carbon dioxide, carbonate radicals, and other products, which are consistent with the experimental findings. These processes primarily result from the conversion of the stable closed-shell O^2- into reactive oxygen ions by electron loss. All surfaces exhibit some degree of layered- and spinel-like phase transitions during the AIMD simulations, consistent with the experiment. This is mainly attributed to the decrease in the Mn-O bond strength and the increase in the Li/O ion vacancy concentration. This study offers valuable theoretical insights into the interface reaction between lithium-rich cathode materials and liquid electrolytes.