Bioinspired nanostructural peptide materials for supercapacitor electrodes

Self-assembly bioinspired peptide nanotubes (PNT) demonstrate diverse physical properties such as optical, piezoelectric, fluidic, etc. In this work, we present our research on environmentally clean bioinspired peptide nanostructured material, to be applied to energy storage devices-supercapacitors (SC). Such an application is based on our recently developed PNT physical vapor deposition technology. It has been found that PNT fine structure and its wettability in electrolytes are the critical factors for a strong variation of the SC capacitance. We show that PNT-coated carbon electrodes enlarge the double-layer capacitance by dozens of times; reaching 800 μF/cm² in a sulfuric acid (normalizing to the electrode geometric surface area of carbon background electrode). The discovered effect is provided by hollow PNT possessing numerous hydrophilic nanoscale-diameter channels, elongated along the PNT axis, which dramatically increase the functional area of carbon electrodes. Another type of the observed PNT morphology is fiberlike highly hydrophobic PNT rods, which do not contribute to the SC capacitance.