Electrochemical investigation of free-standing decreased graphene oxide hydrogel: Fullerenes, Nanotubes and Carbon Nanostructures: Vol 0, No 0

Summary

Free-standing decreased graphene oxide (RGO) hydrogel was synthesized by way of two-stepped hydrothermal discount therapy of aqueous graphene oxide (GO) suspension. GO with excessive interface affinity for overlapping of cross-linking graphene sheets contributes to forming steady-state RGO hydrogel. RGO hydrogel reveals greater B band/G band depth ratio than GO suspension in Raman spectrum evaluation, indicating well-restored hexagonal carbon rings with the improved crystal construction. Free-standing RGO hydrogel might be instantly acted as supercapacitor electrode with out utilizing any substrate materials. The particular capacitance decreases from 253.9 to 92.3 F g⁻¹ in 1.0 M Na₂SO₄ electrolyte and from 275.3 to 125.9 F g⁻¹ in 1.0 M KOH electrolyte when the present density elevated from 0.3 to 4.0 A g⁻¹, presenting the capability retention of 36.4% and 45.7% respectively. Free-standing RGO hydrogel presents particular capacitance in alkaline KOH electrolyte quite than impartial Na₂SO₄ electrolyte. KOH electrolyte with superior ionic diffusion coefficient of hydroxyl ion results in greater present response and electrical double-layer capacitance efficiency. The capacitance retention ratio of 97.8% at 4.0 A g⁻¹ in 1.0 M KOH electrolyte after 1000 charge-discharge cycles presents superior biking stability. Accordingly, free-standing RGO hydrogel utilized effectively as superior supercapacitor electrode presents the promising vitality storage utility.