Understanding of Surface Redox Behaviors of Li2MnO3 in Li-Ion Batteries: First-Principles Prediction and Experimental Validation

Critical degradation mechanism of many cathode materials for Li‐ion batteries is closely related to phase transformations at the surface/interface. Li2MnO3 in x Li2MnO3⋅(1−x) LiMO2 (M=Ni, Co, Mn) provides high capacity, but the Li2MnO3 phase is known to degrade during cycling through phase transformation and O2 evolution. To resolve such degradation problems, it is critical to develop a fundamental understanding of the underlying mechanism. Using first‐principles calculations, we identified the surface delithiation potential (