Electrophoretic Deposition of a Composite Electrode Material of a Supercapacitor Based on Few-Layer Graphite Nanoflakes and Ni(OH)2.

Currently, there is a growing demand for miniaturized power supplies, including planar supercapacitors, whose principle of operation is based on fast redox reactions. This circumstance stimulates investigations of composite structures made of high-surface-area carbon-based materials and transition-metal compounds. In this paper, we report the results of studying coatings based on few-layer graphite nanoflakes FLGN/Ni(OH)2 and their oxidized form OFLGN/Ni(OH)2, obtained by repeated electrophoretic deposition. These coatings are used in prototype parallel-plate (3D) and planar supercapacitors. A processing route using a 450-nm laser for pattern scribing is developed for the latter. It is shown that, by regulating the nickel-ion-source proportion in the suspension from 0.04 to 0.64 g/L, one can control the physical properties of the composite at the deposition stage. The composite's physical properties are studied by cyclic voltammetry, scanning microscopy, and elemental analysis. The peak capacity values are obtained for samples with the minimum concentration (0.04 g/L); they turn out to be 1.51 and 1.31 F/g for the FLGN-containing samples and 1.86 and 1.29 F/g for the OFLGN-containing samples of bulk and planar supercapacitors, respectively. [ABSTRACT FROM AUTHOR]