The XRD measurements performed after 1000 CV were used to investigate the effect of electrochemical treatment on the crystallinity of those thin films, the results are shown in Figure . The data show that the peak intensity of the (002)-peak of the LNO (Figure ) film decreased after 1000 CV cycles, allowing the assumption that OER electrochemical treatment leads to a deterioration of film crystallinity. The weakening of the XRD diffraction peak intensity after OER treatment is attributed to the surface reconstruction of the LNO surface and bulk structure with OER cycling, which has been observed for LNO in previous reports. In addition, the peak position of LNO after 1000 CV shifts from 47.8° to 47.