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Previous studies of graphite from the University of Idaho thermolyzed asphalt reaction (GUITAR) indicated two unique properties that distinguish this material from other sp2 hybridized carbon electrodes. In property i, the standard heterogeneous rate constant across the basal plane (BP) of GUITAR with Fe(CN)63−/4− of 0.01 cm s−1 was 2–7 orders of magnitude greater than for BP‐graphite and graphene. With property ii, the anodic potential limit exceeds other graphite forms by 500 mV. Two new properties are now described. In iii, the hydrogen overpotential in 1 M H2SO4 exceeds other graphitic materials by 500 mV. The combination of ii and iii gives a 3 V window in 1 M H2SO4, which is the largest reported for a graphitic material and competitive with diamond electrodes. In iv, effects of air oxidation on the edge planes (EPs) is reversed by mild cathodic reduction and does not allow for electrolyte intercalation. Based on these characteristics and on atomic force micrographs, we hypothesize that GUITAR may be a new allotrope of carbon. Coupled with expected low costs, GUITAR will find a myriad of applications in electrochemical sensors, water purification, as well as energy storage and conversion.

GUITAR (Graphene from the University of Idaho Thermolyzed Asphalt Reaction) has the classical basal and edge plane morphology of graphites and thin layer graphenes with similar X-ray photoelectron spectroscopy (XPS), Raman and IR characteristics. However previous investigations indicated GUITAR is different electrochemically from graphenes and classical graphites. GUITAR has faster heterogeneous electron transfer across its basal plane and an electrochemical window that exceeds graphitic materials by 1 V. These beneficial properties are examined for application in the negative electrode of the vanadium redox flow battery (VRFB). Graphitic materials in this application suffer from hydrogen gassing and slow electron transfer kinetics for the V 2+/3+ redox couple. Cyclic voltammetry of the V 2+/3+ redox couple (0.05 M V 3+ in 1 M H 2 SO 4) on bare KFD graphite felt gives an estimated standard rate constant (k 0) of 8.2ˆ10´7 cm/s. The GUITAR-coated KFD graphite felt improves that quantity to 8.6ˆ10´6 cm/s. The total contribution of the cyclic voltammetric currents at´1.0 V vs. Ag/AgCl to hydrogen evolution is 3% on GUITAR-coated KFD graphite felt. On bare KFD graphite felt, this is 22%. These results establish GUITAR as an excellent alternative material for the negative electrode in the vanadium redox flow battery.

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