Universal Neural Network Potential-Driven Molecular Dynamics Study of CO2/O2 Evolution at the Ethylene Carbonate/Charged–Electrode Interface

High Resolution Image Download MS PowerPoint Slide Long-term durability and safety are required to develop Li-ion batteries that can operate at high voltages. However, side reactions, including the release of O 2 from the electrode and CO 2 from the organic electrolyte, occur at the positive-electrode/electrolyte interface during charging at high voltages. In this study, universal neural network potential (UNNP)-driven molecular dynamics (MD) calculations are used to investigate the mechanism of the reaction between Li x CoO 2 (0 ≤ x ≤ 1) or Li x NiO 2 (0 ≤ x ≤ 1), as the positive-electrode material, and an ethylene-carbonate-based electrolyte, with a solid–liquid interface composed of ∼1700 atoms. Molecular CO 2 and O 2 evolve from the partially or fully Li-deintercalated Li x NiO 2, while no gas–evolution reactions are observed for Li x CoO 2 . Hence, compared Li x NiO 2, the LiCoO 2 electrode is more stable toward the decomposition of ethylene carbonate in the charged state. The decomposition reactions at the solid–liquid interface during charging are also analyzed using a NN force field. This study provides a robust approach involving MD simulations using UNNP to better understand the side reactions in electrochemical devices, which can guide manufacturers in selecting appropriate materials.