Still a slow, gradual evolution of lattice orientation can be observed right from the start of delithiation. During the first plateau on the electrochemical curve (Figure ) gradual change of d-spacing (Figure ) is also accompanied by a gradual reorientation of different regions of the particle (Supplementary Video 1 (scans 1-18)). This behaviour is consistent with the lattice orientation dynamics that was observed in our previous work . In addition, while approaching the phase transition, sharp wedgeshaped features can be observed on the polar plot (teal, blue and pink -scan 5-18 in Supplementary Video 1). These small regions are located on edges of the particle and show also an increased value of standard deviation of the 115 Bragg peak along Q x and Q y (the in-plane components of the scattering vector), which indicates a higher degree of crystallographic heterogeneities in these regions. The location of these regions also correlates with the most delithiated regions of the crystal (red regions of the strain map in Supplementary Video 1). This also confirms the results of our previous work , where we suggested that the regions with sharp tilt boundaries act as nucleation points for the delithiation process due to high concentration of defects.