Free-standing graphene film growth synaptic network-like nickel-vanadium double hydroxide for supercapacitors

Abstract

Herein, a novel graphene/synaptic network-like nickel-vanadium double hydroxide (rGO/SNNiVDH) film was fabricated by a one-step hydrothermal method. The exquisite structure design is not merely conducive to the rapid transmission of electrons, but also provides a large number of active site for capacitive storage. Correspondingly to innovative structures is excellent electrochemical performance, the rGO/SNNiVDH obtains an excellent specific capacitance of 1726.7 F g−1 at a current density of 1 A g−1 and good rate capability with the capacitance value can still maintain 53.5 % even at the current density of 10 A g−1. Furthermore, the assembled asymmetric supercapacitor comprising rGO/SNNiVDH and active carbon (AC) as positive and negative electrodes respectively achieves a high energy density of 77.3 Wh kg−1 even under a power density of 7250 W kg−1. The rGO/SNNiVDH//AC exhibits excellent cycle stability with high capacitance retention of 96.3 % after 5000 cycles at a high current density of 10 A g−1. The study provides a new research perspective for the growth of other transition metal double hydroxides on the surface of rGO to obtain more transition metal double hydroxides with special morphology for high performance supercapacitors.