Graphene based supercapacitor fabricated by vacuum filtration deposition

A novel method involving vacuum filtration deposition (VFD) of graphene suspension is developed in this study to fabricate graphene based nickel foam electrode for supercapacitor. Acid-treated graphene nanosheets in a suspension can be easily deposited in the pores of nickel foam in large quantity using this method, thus producing supercapacitors with large energy capacity. Structural and morphological characterizations of as prepared electrodes have been carried out using scan electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. Electrochemical performance of as prepared electrode has also been investigated through cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge analyzer, in comparison with electrodes prepared via existing technique. Our results demonstrated that the new electrode, while achieving much greater energy capacity due to large active substance incorporated, still maintains a relatively high power density and a good cycle performance in 6 M KOH electrolyte. Our results also demonstrated that a supercapacitor made of the existing electrophoretic deposition based electrodes will lose its entire capacitance after certain time period (20 days in our study); whereas the VFD based one retains virtually all its performance after the same period. The present study shows the potential application of this method for fabrication of supercapacitor with much improved energy capacity.

► Achieving very small internal resistant and excellent electrochemical response.
► Unlimited in the working medium able to incorporate in.
► Much easier to scale up.
► Retaining virtually all capacitance after a month.