In the presence of both salts, a very fine Zn deposit is obtained. The changes in the morphology can be associated with the interfacial structure shown in Fig. 4. It is evident that the innermost interfacial layer significantly changes on addition of Zn(TfO)2 and of Zn(TfO)2 + ZnO compared to the pure IL, whereas in the case of ZnO addition, no change occurs. This suggests that the change in the innermost layer affects the zinc deposition process. Furthermore, in the case of Zn(TfO)2 + ZnO, the innermost layer appears to show the presence of more than one species (Fig. 4d) which might have led to the deposition of very fine zinc structures as seen in Fig. 6e and f. The sustainability of the innermost layer might also be a reason for not having dendritic growth as evidenced in Fig. 7g after 170 cycles