Insights into the interface reaction between electrolyte and Li2MnO3 from ab initio molecular dynamics simulations

Abstract

The complex interface reaction plays a critical role in the Li₂MnO₃ cathode material with high energy density. Here, the interface reactions between the liquid electrolyte molecules and the typical surfaces of Li₂MnO₃ are systematically investigated by ab initio molecular dynamics (AIMD) simulation and first-principles calculation. We demonstrate that the decomposition of electrolyte molecules on the different surfaces of Li₂MnO₃ exhibits a high degree of similarity. The carbonyl carbon (C_C) and ether oxygen (O_E) of the electrolyte molecule that bind to the O and Mn of the Li₂MnO₃ surface, respectively, are the prerequisites for the decomposition of the electrolyte molecules. The redox reaction between the electrolyte molecule and the surface of Li₂MnO₃ considerably weakens the strength of the C_C–O_E bond. In particular, the surface of (001) is an inert surface, which does not react with electrolyte molecules through our AIMD simulations. This is due to the large electron occupation energy gap between the electrolyte molecule and the (001) surface. This study provides a theoretical insight into the interface reaction between lithium-rich cathode materials and liquid electrolytes.