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

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 O2- 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.

The stability of CsPb(BrxCl1-x)3 all-inorganic mixed halide perovskites.

The use of mixed halide perovskites in the preparation of blue light-emitting diodes (LEDs) is considered to be the most effective and direct approach. However, the introduction of chlorine (Cl) element might raise stability issues in the system and lead to low efficiency, thereby impeding the development of deep blue light-emitting diodes with high efficiency and stability. Determining the alloy concentration and the atomic distribution of bromine-chlorine (Br-Cl) mixed systems is essential for further application of deep blue light-emitting diodes. In this work, we have systematically investigated the stability of bromine-chlorine (Br-Cl) mixed alloy systems in various substitution configurations using high-throughput theoretical calculations. Based on this, we have examined the relationship between configuration stability and three aspects: the type of octahedra, the orientation of the octahedra and the Pb-X-Pb distortion angle in the configuration.