Synergistic Effect of Mn3+ Formation–Migration and Oxygen Loss on the Near Surface and Bulk Structural Changes in Single Crystalline Lithium-Rich Oxides

Micron-sized single crystal particles could be used to intensify structural changes between bulk and surface area during the charge–discharge process owing to their long-range order. In this study, the effects of Mn 3+ formation–migration and oxygen loss on the structure change from the bulk side to the near surface in single crystalline Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 were decoupled by regulating the voltage windows of 2–4.5, 3–4.8, and 2–4.8 V because Mn 3+ formation–migration and oxygen loss mainly occurred below 3 V and beyond 4.5 V, respectively. It is found that oxygen vacancies and phase transformation can be retarded by suppressing the formation–migration of Mn 3+ . Finally, we also conducted an important insight that boron ion doping in tetrahedral site could be used to suppress Mn 3+ migration from octahedral site to tetrahedral site and disrupt the synergistic effect of Mn 3+ migration and oxygen loss.