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

By Lee, Jae Ah; Shin, Min Kyoon; Kim, Shi Hyeong; Kim, Seon Jeong; Spinks, Geoffrey M.; Wallace, Gordon G.; Ovalle-Robles, Raquel; Lima, Márcio D.; Kozlov, Mikhail E. & Baughman, Ray H.
Published in ACS Nano NULL 2012

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 ∼66 nm and low areal density of ∼15 μg/cm2exhibited 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 ∼40 F/cm3 at 100 V s -1 (∼40 and ∼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 ∼5 V s -1. High mechanical strength and flexibility of the hybrid nanomembrane enabled twisting it into microsupercapacitor yarns with diameters of ∼30 μm. The yarn supercapacitor showed stable cycling performance without a metal current collector, and its capacitance decrease was only ∼6% after 5000 cycles. Volumetric energy and power density of the hybrid nanomembrane was ∼70 mWh cm -3 and ∼7910 W cm -3, and the yarn possessed the energy and power density of ∼47 mWh cm -3 and ∼538 W cm -3.

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