The phase analysis was performed by X-ray diffraction (XRD) measurements in the 2θ range of 10º -60°. We observe prominent changes in the diffraction pattern of the exfoliated membranes compared to bulk Mn3O4, as shown in Figure and Figure (SI Section 1), respectively. The XRD profile of bulk Mn3O4 is indicative of a single phase, polycrystalline nature (Figure ). Upon exfoliation, peak positions changed with reference to that of the bulk structure.