Hybrid Nanomembranes for High Power and High Energy Density Supercapacitors and Their Yarn Application

Abstract

We report mechanically robust, electrically conductive, free-standing, and transparent hybrid nanomembranes made of densified carbon nanotube sheets that were coated with poly (3,4-ethylenedioxythiophene) using vapor phase polymerization and their performance as supercapacitors. The hybrid nanomembranes with thickness of similar to 66 nm and low areal density of similar to 15 mu g/cm(2) exhibited high mechanical strength and modulus of 135 MPa and 12.6 GPa, respectively. They also had remarkable shape recovery ability in liquid and at the liquid/air interface unlike previous carbon nanotube sheets. The hybrid nanomembrane attached on a current collector had volumetric capacitance of similar to 40 F/cm(3) at 100 V s(-1) (similar to 40 and similar to 80 times larger than that of onion-like carbon measured at 100 V s(-1) and activated carbon measured at 20 V s(-1), respectively), and it showed rectangular shapes of cyclic voltammograms up to similar to 5 Vs(-1). High mechanical strength and flexibility of the hybrid nanomembrane enabled twisting it into microsupercapacitor yarns with diameters of similar to 30 mu m. The yam supercapacitor showed stable cycling performance without a metal current collector, and its capacitance decrease was only similar to 6% after 5000 cycles. Volumetric energy and power density of the hybrid nanomembrane was similar to 70 mWh cm(-3) and similar to 7910 W cm(-3), and the yam possessed the energy and power density of similar to 47 mWh cm(-3) and similar to 538 W cm(-3).