Fabricating strongly coupled V2O5@PEDOT nanobelts/graphene hybrid films with high areal capacitance and facile transferability for transparent solid-state supercapacitors

Abstract

Transparent energy-storage devices are of enormous significance to the continued growth of flexible and wearable electronics in the foreseeable future. The development of transparent supercapacitive electrodes that possess not only high optical transmittance but also intriguing features of energy-storage capability, transferability and outstanding durability, remains a remarkable challenge. Here we demonstrate a polymer-glued strategy to fabricate the conjugated transparent hybrids of V2O5 and graphene, whereby the poly(3,4-ethylenedioxythiophene) (PEDOT) forms a conformal coating on the surface of V2O5 nanobelts and functions as a glue. Interestingly, the PEDOT-glued V2O5/graphene (VP-G) is easy-transferrable onto various flat and even curved substrates. When served as a transparent supercapacitive electrode, the VP-G exhibits a high areal capacitance of 22.4 ​mF ​cm−2 ​at an optical transparency of 70%. As unveiled by experimental results and density functional theory (DFT) calculations, both the kinetic blocking of the PEDOT layer and the anchoring capability of graphene upon soluble vanadium ions contribute synergistically to the unusual electrochemical stability. Transparent, high-energy-density solid-state supercapacitors made of the as-fabricated hybrids are constructed, exhibiting a high energy density of 0.18 ​μW ​h cm−2 ​at 11 ​μW ​cm−2. As expected, the constructed transparent supercapacitors demonstrate an excellent cycling stability over 50 ​000 cycles with capacitance retention of 92.4%. These results show its great potential as promising transparent devices.