Preparation and characterization of high surface area, high porosity carbon monoliths from pyrolyzed bovine bone and their performance as supercapacitor electrodes

Bovine cortical bone was pyrolyzed to produce a network of conductive carbon entwined with native hydroxyapatite that maintains its macroscopic structure during pyrolysis and prevents collapse of the carbon. Self-supporting conductive carbon monoliths were prepared by removing the hydroxyapatite with acid or ethylenediaminetetraacetic acid. The specific surface areas of these monoliths were determined by nitrogen adsorption, and their chemical structure was characterized using Raman spectroscopy. The monoliths exhibit specific surface areas and Raman spectra similar to those of amorphous carbons. Capacitance was assessed using the monoliths as the working electrodes in three-electrode cells, and two-electrode devices in which both electrodes were monoliths. Individual monoliths exhibit specific capacitances of 134 +/- 11 F/g in aqueous solutions of potassium nitrate and 108 +/- 9 F/g in the ionic liquid 1-ethyl-3-methylimidizolium bis(trifluoromethylsulfonyl)imide. The capacitance of individual 6 mm diameter by 1 mm thick electrodes was typically on the order of 0.2 Farads. (C) 2012 Elsevier Ltd. All rights reserved.