Preparation and capacitance of V2O5/holey graphene hybrid aerogel electrode with high performance

Abstract

V2O5/holey graphene hybrid aerogel electrode (VHGA) with 3D hierarchical porous structure is fabricated by hydrothermally treating a mixed suspension of holey graphene oxide (HGO) nanosheets, acetic acid, and NH4VO3 at 180 °C for 24 h and followed by freeze drying V2O5/holey reduced graphene oxide hydrogel (HRGO). The prepared VHGA electrodes show an interconnected and stable 3D porous network, and V2O5 nanobelts are randomly embedded in the aerogel, preventing the restacking of HRGO nanosheets. VHGA-2 hybrid aerogel electrode exhibit high specific capacitance (264 F g−1) at a current density of 0.25 A g−1, outstanding rate capability (77%) at various current densities from 0.5 to 10 A g−1 and good cycling performance (85%) after 1000 cycles in 0.5 M K2SO4 aqueous electrolyte. HRGO nanosheets provide an electronic conduction channel, and the 3D hierarchical porous structure shortens the diffusion length of electrolyte ions. The structural advantages of VHGA hybrid aerogel electrode are beneficial to the capacitive behavior. This facile and efficient preparation method for VHGA electrode can be further developed for preparing other transition metal oxide/holey graphene hybrid aerogel electrodes with desired structure and superior properties.