fig4

Figure 4. (A) Atomic models of O3 phase (space group R$$\overline{3m}$$), O3 phase with partially transited O1 phase, and pure O1 phase. Li, Ni, and O are denoted by green, gray, and red symbols, respectively. This figure is quoted with permission from Wang et al.^[55]. (B) Oxygen vacancy formation energy during delithiation of LiNiO₂, (C) Configuration for Ni migration in Li_0.5NiO₂, Vo1, Vo2, and Vo3 represents oxygen vacancies neighboring with diffusive Ni ion, (D) The migration barriers for Ni ions to diffuse from transition metal layer to Li layer, under different situations (Pristine: no neighboring oxygen vacancy; Vo1: with neighboring vacancy Vo1; Vo1 + Vo2: with neighboring vacancies Vo1 and Vo2; Vo3: with neighboring vacancy Vo3). This figure is quoted with permission from Kong et al.^[58].