Structural elucidation of the degradation mechanism of nickel-rich layered cathodes during high-voltage cycling

Phase transition occurring during cycling plays a fundamentally important role in the cycling performance of nickel-rich cathodes. Here, splitting of two O3 phases, rather than the often observed O1 phases in the conventional LiCoO 2 electrode, was discovered in LiNi 0.85 Co 0.10 Mn 0.05 O 2 at a high-voltage region (>4.6 V). Such degradation could be mitigated via Al doping. A splitting of two O3 phases, rather than the often observed O1 phases in the conventional LiCoO 2 electrode, was discovered in the LiNi 0.85 Co 0.10 Mn 0.05 O 2 at high-voltage region (>4.6 V) by in situ high-resolution synchrotron radiation diffraction.