Current collector-free strategy for rGO paper electrosynthesis and its application in supercapacitors
摘要
The goal of this work was to develop a free-standing and current collector-free supercapacitor based on reduced graphene oxide (rGO) paper prepared by filtration and electrochemical reduction of graphene oxide (GO). For this purpose, the reduction was conducted at a constant potential of − 1.4 V vs. saturated calomel electrode in 0.1 M KCl solution. The working electrode was designed so that only a small portion of the GO comes into contact with the Ti rod to provide a current collector-free reduction. Conductivity measurements, XPS, Raman spectroscopy and XRD measurements demonstrated that the reduction process provided good conductivity even though GO was not completely reduced. Furthermore, it was shown that by using a current collector-free process, the homogeneous reduction of rGO paper was achieved. Three different configurations of supercapacitors with 0.5 M Na2SO4 were assembled: a supercapacitor completely covered by a Ni current collector, a supercapacitor with 1/2 of the active material covered by Ni and 1/4 of the active material covered by Ni. The good reversibility and specific capacitance values of up to 31 F g−1 at 50 mV s−1 were obtained for the supercapacitor without current collector, which is not significantly different from the value of the supercapacitor completely covered by Ni current collector (43 F g−1). The results obtained in this work indicate the successful fabrication of free-standing and current collector-free supercapacitor.