aZn dissolution (mmol L−1) in a 4 M KOH solution.bScanning electron microscopy (SEM) micrographs of uncoated ZnO and ZnO@TiNxOyanode before and after the charging process.cX-ray diffraction patterns for ZnO nanorods and a ZnO@TiNxOyanode before and after the charging process.dElectrochemical...