Unravelling the origin of irreversible capacity loss in NaNiO2 for high voltage sodium ion batteries

The dissymmetric phase transformation and structure evolution mechanism of layered NaNiO2 material during initial charge and discharge cycling were comprehensive understood with transmission X-ray microscopy and synchrotron-based X-ray diffraction. We directly observed the structural evolution of the NaNiO2 cathode in sodium-ion batteries and elucidated the irreversible phase transformation mechanism during the initial electrochemical cycling.307