Bioinspired peptide nanotubes as supercapacitor electrodes

Abstract

Bioinspired materials offer new routes in nanotechnology. These materials are composed from chemically synthesized biomolecules and inspired by natural biological structures. They are self assembled into highly ordered nanostructures (nanotubes, nanospheres, etc.) from elementary building blocks of biological origin such as peptide and proteins. We developed a new technique of physical vapor deposition of peptide nanotubes (PNT) and applied it to electrochemical energy storage devices—supercapacitors (SC). In this work, aligned and homogenously distributed diphenylalanine PNT have been used to modify carbon electrodes for SC devices. Electrochemical properties of PNT coatings of different density and height, modifying carbon electrodes have been studied. We have found that aligned PNT arrays significantly increase the double layer capacitance of the carbon electrodes. The found enlargement of the PNT-modified electrode capacitance has been ascribed to increasing of usable electrode surface area of the carbon electrodes coated by PNT. We show that the critical factor of the accumulation process of the electrolyte ions at the PNT-modified electrode surface is a wetting process of the PNT nanoscale hydrophilic channels by aqueous electrolyte.