Fig. 5: The high oxidation states of dopants promote the Li/TM ordered structure.
From: Transition metal-doped Ni-rich layered cathode materials for durable Li-ion batteries
a, b HAADF TEM images and derived structural models of Al-NC90 and Ta-NC90, respectively. c–g Bright-field images and corresponding SAED patterns of single primary particles of Mg-NC90, Al-NC90, Ti-NC90, Ta-NC90, and Mo-NC90. h Calculated [100] zone axis diffraction patterns for the normal layered structure and ordered superlattice structure. i Post-mortem analysis of a discharged Ta-NC90 cathode after 3000 cycles using TEM. Low magnification TEM image of a cycled Ta-NC90 particle and corresponding electron diffraction pattern (inset). j Schematic comparing the relative structural stability of the normal layered and ordered structures in highly delithiated states and after long-term cycling.
