Formation of surfaces oxide vacancies in porous ZnCoO nanoflowers for enhanced energy storage performance.

A cost-effective and large-scale method for synthesizing ZnCoO nanoflowers with surface oxygen vacancies as electrode materials for supercapacitors is presented. The existence of oxygen vacancies on the surface of the ZnCoO nanoflowers has been confirmed through X-ray photoelectron spectroscopy (XPS). The energy bands and density of states (DOS) of ZnCoO are examined using density functional theory, revealing that treatment with NaBH reduces the band gap of ZnCoO while increasing the DOS near the Fermi level compared to pristine ZnCoO. Furthermore, the specific capacitance of reduced ZnCoO is nearly double that of its unmodified counterpart. This straightforward and practical approach significantly enhances both conductivity and specific capacitance in metal oxides, making it applicable to other similar materials.