Capacitance enhancement in supercapacitors by incorporating ultra-long hydrated vanadium-oxide nanobelts into graphene

The oriented synthesis of high-performance nanobelt/graphene hybrids remains a challenge by one-step environmentally friendly process for supercapacitors. Here, PEG-6000 manipulation was employed to facilitate ultra-long V₂O₅·0.5H₂O nanobelts on surface of reduced graphene oxide (rGO). As a result, due to faster and efficient electron transfer and collection, V₂O₅·0.5H₂O/rGO hybrid (rGO: 5 wt%–50 wt%) significantly enhances electrochemical capacitance for supercapacitors. Especially, introduction of 50 wt% rGO in the hybrid (denoted as 50 wt% rGO-V) exhibits a high capacitance of 649 F g⁻¹at a scan rate of 5 mV s⁻¹in a neutral KCl electrolyte. On the other hand, the hybrid material shows a high-rate capacitance of 160 F g⁻¹at a current density of 1 A g⁻¹. Additionally, capacitance retention of 93% was obtained after 600 cycles, implying excellent cycling stability in the 50 wt% rGO-V hybrid. This study is beneficial to understand synergetic effects in V₂O₅·0.5H₂O/rGO hybrid materials and even useful for oriented synthesis of hybrid materials in other energy storage devices.