Reduced Graphene Oxide on Nickel Foam for Supercapacitor Electrodes

Abstract

The focus of this paper is the investigation of reduced graphene oxide (GO)/nickel foam (RGON) samples for use as supercapacitor electrodes. Nickel foam samples were soaked in a GO suspension and dried before being subjected to two different methods to remove oxygen. Atmospheric pressure annealed (APA) samples were treated with a varying number (10–18) of nitrogen plasma jet scans, where sample temperatures did not exceed 280 °C. Furnace annealed (FA) samples were processed in an atmosphere of hydrogen and argon, at temperatures ranging from 600 °C to 900 °C. Environmental Scanning Electron Microscope (ESEM) data indicated that the carbon to oxygen (C:O) ratio for APA samples was minimized at an intermediate number of plasma scans. Fourier Transform Infrared Spectroscopic (FTIR) and Raman spectroscopic data supported this finding. ESEM analysis from FA samples showed that with increasing temperatures of annealing, GO is transformed to reduced graphene oxide (RGO), with C:O ratios exceeding 35:1. X-ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD) data indicated the formation of RGO with an increasing annealing temperature until 800 °C, when oxygen reincorporation in the surface atomic layers becomes an issue. Supercapacitors, constructed using the FA samples, demonstrated performances that correlated with surface atomic layer optimization of the C:O ratio.

Modifying Reduced Graphene Oxide by Conducting Polymer Through a Hydrothermal Polymerization Method and its Application as Energy Storage Electrodes

“…After the anchoring of PEDOT particle on the rGO sheets at the proper GO concentration, the introduction of PEDOT pseudocapacitance would enhance the specific capacitance obviously than pure rGO electrode. Our composite electrodes show higher specific capacitance (SC) than reported pure rGO electrodes with varied architecture [64,65], our previously reported rGO/PEDOT composite electrode prepared through an oxidant polymerization method [66], composite rGO/ PEDOT:PSS electrodes [67,68], composite rGO/ Polypyrrole (PPY) [69], and our PEDOT/rGO electrode obtained from physical mixing ( Table 3). These electrodes also show comparable SC performance with a high SC rGO/polyaniline (PANi) electrode [70], but show higher conductivity which is a benefit to construct high power density devices.…”

Flexible Solid‐State Symmetric Supercapacitors Using HxWO3@Reduced Graphene Oxide Composite with High Volumetric Energy and Power Densities

“…The analysis of CV and GCD plots revels that amongst all the samples, WG1‐2 electrode shows better electrochemical performance in both positive and negative potentials. The CV plot of WG1‐2 (Figure a) are almost rectangular types with presence of red‐ox peaks, indicating that the charge storage process involves both the electrical double layer formation as well as reversible proton adsorption/desorption . The charge storage process of WG hybrids involves both the electrical double layer capacitance and pseudocapacitance generated from the nature of both rGO and H x WO 3 .…”

“…But due to less conductivity of GO it does not show capacitance property, hence reduced graphene oxide is required to make hybrid with WO 3 or WO 3 .nH 2 O to yield good capacitance property. The charge storage process of rGO involves both electrochemical double layer formation and pseudocapacitance assisted by its redox active oxygenated functional groups . Furthermore its large surface area, 2D sheet like structure and large number of oxygenated groups make it an emerging host material to make composites with different oxophilic nano materials.…”

Performance-Enhanced Activated Carbon Electrodes for Supercapacitors Combining Both Graphene-Modified Current Collectors and Graphene Conductive Additive

“…The conductivity and adhesion with active materials of a current collector can directly influence the specific capacitance [ 24 , 25 , 26 , 27 ]. Nickel is one of the most popular current collectors of supercapacitors owing to its good conductivity, mechanical properties, stability in aqueous alkali and strong adhesions with active materials [ 28 , 29 , 30 ]. To further improve the above properties is still the main research orientation in modifying nickel current collectors.…”