Electrodeposited Films of Graphene, Carbon Nanotubes, and Their Mixtures for Supercapacitor Applications

Advanced energy storage devices are gaining attention due to increased demand for portable electronics. In this work, stable aqueous dispersions of graphene, carbon nanotubes, and their mixtures are produced with the aid of the surfactant sodium dodecylbenzene sulfonate. The method of electrodeposition is employed for the fabrication of films on copper, using the respective dispersions. These specimens are exposed to radiation of a xenon lamp, and characterization of the electrode material is carried out by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, attenuated total reflectance–Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. All-solid-state symmetric supercapacitors are successfully fabricated with the use of a gel electrolyte and the respective electrodeposited films on the electrodes. The electrochemical performance of the supercapacitors is evaluated by different electrochemical methods including cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The all-solid-state supercapacitor with the best electrochemical properties is the symmetric supercapacitor from irradiated electrodeposited films of carbon nanotubes on copper with areal capacitance 78.8 μF/cm2, energy density 0.04 μW·h/cm2, and power density 63.03 μW/cm2. Due to the facile and toxic-free scale-up of the electrodeposited process and the aqueous dispersions based on the carbon nanomaterials, the developed all-solid-state supercapacitor is suitable for energy storage devices.