A bifunctional asymmetric electrochromic supercapacitor with multicolor property based on nickel oxide/vanadium oxide/reduced graphene oxide

A ternary nickel oxide/vanadium oxide/reduced graphene oxide (NiO/V2O5/rGO) was designed as a positive electrode of an asymmetric electrochromic supercapacitor. The uniform distribution of the elements (C, Ni, O, V) in the wrinkle-like sheet of NiO/V2O5/rGO was observed via elemental mapping. NiO/V2O5/rGO electrode demonstrated an outstanding specific capacitance of 1265.5 F/g compared to rGO (40.9 F/g), NiO (130.5 F/g), V2O5 (521.2 F/g) and NiO/V2O5 (707.3 F/g). The developed nickel oxide/vanadium oxide/ reduced graphene oxide//copper-based metal-organic framework/reduced graphene oxide (NiO/V2O5/rGO//MrGO) electrochromic supercapacitor (EC-SC) device that operated at wide operating potential successfully delivered maximum specific energy of 41.4 Wh/kg and excellent cycling stability (capacitance retention of 92.2%) over 4000 CV cycles. Interestingly, the level of energy stored in the prepared asymmetric EC-SC device can be visually detected as it implied color changes from dark green to orange. NiO/V2O5/rGO//MrGO with excellent optical and supercapacitive properties is designated as a promising electroactive material for next generation electrochromic supercapacitors.

Automated summary

A ternary nickel oxide/vanadium oxide/reduced graphene oxide electrode was developed, demonstrating outstanding specific capacitance and excellent cycling stability. The device also allowed for visual detection of energy storage through color changes. Therefore, it shows promising potential for future applications.