fig2

Figure 2. (A) Formation energy (E_f) of one pair of Ni/Li exchange in LiNi_1/3Mn_1/3Co_1/3O₂ (333), LiNi_0.4Mn_0.4Co_0.2O₂ (442), LiNi_0.5Mn_0.5O₂ (550), LiNi_0.6Mn_0.2Co_0.2O₂ (622), and LiNi_0.7Mn_0.15Co_0.15O₂ (71515) with zigzag TM arrangements. The local configurations of Ni/Li exchanges with the lowest and highest E_f are shown in each material. The shaded areas show the general trend of the E_f variation for the Ni/Li exchange, and the schematics at the bottom represent the nonequivalent ion environment for the antisite Li ion in the TM layer. This figure is quoted with permission from Zheng et al.^[26]. (B) Differential capacity as a function of cell voltage (dQ/dV vs. V) of 2nd charge and discharge of LiNiO₂, LiNi_0.95Al_0.05O₂, LiNi_0.95Mn_0.05O₂, LiNi_0.95Mg_0.05O₂, and LiNi_0.95Co_0.05O₂. This figure is quoted with permission from Li et al.^[27]. (C) The c-axis lattice parameter changes in the as-prepared samples obtained from Rietveld refinements. The lattice changes of the c axes of NC64 (LiNi_0.6Co_0.4O₂), NMC622 (LiNi_0.6Mn_0.2Co_0.2O₂) and NM64 (LiNi_0.6Mn_0.4O₂) were 5.0%, 2.9% and 1.0%, respectively. This figure is quoted with permission from Liu et al.^[28].