Bifunctional ternary manganese oxide/vanadium oxide/reduced graphene oxide as electrochromic asymmetric supercapacitor

Abstract

A bifunctional ternary manganese oxide/vanadium oxide/reduced graphene oxide (MnO 2 /V 2 O 5 /rGO) was developed for asymmetric electrochromic supercapacitor (EC-SC) application. The elemental mapping revealed uniformly distributed MnO 2 , V 2 O 5 and rGO, depicting homogenous synthesis of the hybrid composite. The phase composition, vibration modes and valance state of the ternary composite were analyzed via X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis, respectively. Interestingly, the as-prepared MnO 2 /V 2 O 5 /rGO composite disclosed tremendous C sp of 1403.5 F/g, which was higher compared to MnO 2 /V 2 O 5 (801.1 F/g), V 2 O 5 (613.1 F/g), MnO 2 (126.7 F/g) and rGO (60.7 F/g). MnO 2 /V 2 O 5 /rGO that appeared in dark green switched its visual color to orange at the charged state, confirming the electrochromic property. The bifunctional manganese oxide/vanadium oxide/reduced graphene oxide//copper-based metal-organic framework/reduced graphene oxide (MnO 2 /V 2 O 5 /rGO//MrGO) asymmetrical EC-SC device revealed outstanding cycling stability (90.3% charge retention over 5000 cycles), tremendous specific capacitance (652.7 F/g) and maximum specific energy (60.4 Wh/kg). MnO 2 /V 2 O 5 /rGO//MrGO asymmetrical EC-SC device demonstrated reversible color changes from dark green to orange at the discharged and charged states, respectively. The significantly great electrochromic and supercapacitive performance revealed that MnO 2 /V 2 O 5 /rGO//MrGO is an outstanding electroactive candidate for the next generation of electrochromic supercapacitors.