Interconnected three-dimensionally hierarchical heterostructures with homogeneously-dispersed V2O5 nanocrystals and carbon for high performance supercapacitor electrodes

In this article, a simple “liquid phase impregnation template” strategy has been developed to synthesize hierarchically porous V2O5/C (HPVC) nanocomposites by using commercial V2O5 and phenol-formaldehyde (PF) resol as precursors and polystyrene opal microspheres as template. The amount of vanadium sol in the vanadium-PF precursor has a significant effect on the morphology and microstructure of the resulting HPVC nanocomposites. Due to the intact interconnected hierarchical network framework and the homogeneous dispersion of constitutive V2O5 nanocrystals and carbon phases, the optimal sample HPVC2 with higher surface area (645 m2 g−1) and mesopore surface area (394 m2 g−1) and an appropriate content of V2O5 (38.7 wt.%), is found to be the most efficient one as supercapacitor electrode with a high specific capacitance up to 492.1F g−1 at a scan rate of 5 mV s−1 in the three-electrode system. When used as symmetric electrode, the HPVC2//HPVC2 supercapacitor exhibits a high energy density up to 87.6 Wh kg−1 at a power density of 497 W kg−1, which greatly surpasses those of pure single-component counterparts and others reported V2O5/C composites. The present work conceptually provides a facile way for integrating transition metal oxide with carbon in hierarchically porous nanostructure to synthesize hybrid electrode materials for advanced energy storage/conversion devices.