Oxygen Vacancies Enhancing Capacitance of MgCo2O4 for High Performance Asymmetric Supercapacitors

Abstract Here, we report a facile strategy to synthesize MgCo2O4 with abundant oxygen vacancies (OV-MgCo2O4) using for the electrode materials of asymmetric supercapacitors (ACS). Benefiting from the NaBH4 reduction treatment to offer oxygen vacancies, the specific capacitance of OV-MgCo2O4 was improved to 460 F g-1 (1 A g-1), much higher than untreated MgCo2O4 (340 F g-1 at 1 A g-1). We fabricated OV-MgCo2O4//AC ACS device to investigate the further application of OV-MgCo2O4. This hybrid ACS exhibits excellent specific capacity of 52.5 F g-1 (0.4 A g-1), with a great energy density of 18.7 Wh kg-1 (320 W kg-1). Our work demonstrates the important role of oxygen vacancies in improving the capacity of metal oxides.