Surface engineering of Co3O4 nanoribbons forming abundant oxygen-vacancy for advanced supercapacitor

Abstract

The development of high-efficiency metal oxide electrode materials with high reaction kinetics and excellent conductivity are a cutting-edge strategy to obtain high-performance energy storage devices. Forming oxygen vacancy on the surface of the metal oxide tune electronic structure is a feasible approach to boost the electroactive of metal oxides for supercapacitor. Herein, an effective solution reduction method is reported for tuning the electronic structure of Co3O4 nanoribbons reacting with NaBH4 to enhance the faradaic redox reaction for high electrochemical performance. The vacancy-rich defects can endow more electroactive sites and reduce the electrical resistance for the enhanced supercapacitor performance. Therefore, compared to pristine Co3O4 (347.4 F g−1), the reduced Co3O4 (R-Co3O4) shows a high specific capacitance (Cs, 464.9 F g−1) and a reduced charge transfer resistance. The asymmetric supercapacitor (ASC, R-Co3O4// active carbon) exhibits an energy density of 18.6 Wh kg−1 at the power density of 400 W kg−1 and excellent cycling stability. Such a feasible approach realizes the electronic tuning by creating oxygen vacancy that provides sufficient active sites and activates the fast faradaic redox reaction with enhanced energy storage ability of redox-active electrode materials.