Precious metal–carbon framework materials for supercapacitors

Abstract

Precious metals (PM) have received considerable attention recently due to their corrosion resistance, electrical conductivity, variable oxidation states, and impressive theorized capacitance. However, they are scarce and expensive, and have low cyclic stability, thus limiting their industrial applications. This article discusses extensively the fabrication of ruthenium oxides in their nano form with different carbon nanomaterials. The carbon materials covered are graphene, carbon nanotubes, carbon dots, carbon onions, activated carbon, carbon black and carbon fiber. Additionally, ruthenium nitrates and sulfites, as well as other precious metals such as gold nanoparticles, iridium oxide nanoparticles, palladium/palladium oxide nanoparticles, platinum nanoparticles/wires, silver nanoparticles/nanowires, and their carbonaceous composites are discussed. The shortcomings of pristine carbon material supercapacitors, and the use of PM to achieve high power density in composite PM–carbon material supercapacitors, are also evaluated.