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

Co 3 O 4 nanoribbons with abundant O vacancy acting as electrode exhibited excellent performance in energy storage. • 1D Co 3 O 4 NRs with abundant oxygen vacancy are successfully prepared. • The increased oxygen vacancy provides optimizes the electronic structure and further enhances the electrochemical performance. • R-Co 3 O 4 NRs exhibit high specific capacitance than the pristine Co 3 O 4 NRs. • ASC based on this electrode shows good rate capability and cycling performance. 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 Co 3 O 4 nanoribbons reacting with NaBH 4 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 Co 3 O 4 (347.4 F g −1 ), the reduced Co 3 O 4 (R-Co 3 O 4 ) shows a high specific capacitance ( C s , 464.9 F g −1 ) and a reduced charge transfer resistance. The asymmetric supercapacitor (ASC, R-Co 3 O 4 // 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.