Formation of surfaces oxide vacancies in porous ZnCo2O4 nanoflowers for enhanced energy storage performance
Deyang Zhang, Binhe Feng, Wenbo Guo, Jinbing Cheng, Kangwen Qiu, Ying Guo
Abstract
A cost-effective and large-scale method for synthesizing ZnCo 2 O 4 nanoflowers with surface oxygen vacancies as electrode materials for supercapacitors is presented. The existence of oxygen vacancies on the surface of the ZnCo 2 O 4 nanoflowers has been confirmed through X-ray photoelectron spectroscopy (XPS). The energy bands and density of states (DOS) of ZnCo 2 O 4 are examined using density functional theory, revealing that treatment with NaBH 4 reduces the band gap of ZnCo 2 O 4 while increasing the DOS near the Fermi level compared to pristine ZnCo 2 O 4 . Furthermore, the specific capacitance of reduced ZnCo 2 O 4 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.