Direct growth of carbon nanofiber forest on nickel foam without any external catalyst

Abstract

Interest in the direct growth of carbon nanostructures on metal substrates is growing, especially in the field of supercapacitors, fuel cells, batteries and sensors. This paper presents results on the growth of carbon nanofibers (CNF) without the requirement of an external catalyst directly on nickel foam (Ni-foam) at a relatively low temperature of 400°C. Etching of Ni-foam leads to the growth of CNF forests covering entirely the internal surfaces of the Ni-foam, with CNF diameters that can be tuned between 78±32nm and 375±35nm through a change in the growth temperature between 400 and 700°C. Etching was found to be important to obtain a uniform surface CNF coverage and growth, particularly at higher temperatures. These CNF/Ni-foam composites yield 3D nano-scale internal forest structures in good contact with the micro-scale porosity of the metallic foam electrode. This work provides a foundation to use binderless CNF composite electrodes to obtain higher capacitance.