The Properties of Carbons Derived through the Electrolytic Reduction of Molten Carbonates under Varied Conditions: Part I. A Study Based on Step Potential Electrochemical Spectroscopy

Abstract

Carbons have been produced through the electrolytic reduction of molten alkali metal carbonate salts under a range of conditions. The resultant carbons consist of both graphitized and amorphous phases. The carbon surface has also been shown to be heavily functionalized with oxygen containing groups. Their charge storage capabilities as electrochemical capacitor materials have been investigated using cyclic voltammetry and step potential electrochemical spectroscopy (SPECS). Trends in carbon performance with electrodeposition conditions have been identified, and carbons with a specific capacitance as high as 375 F.g−1 have been obtained at scan rates of 10 mV.s−1. With respect to temperature of carbon deposition, carbon electrodeposited at 500°C has been identified as the best electrical double layer capacitor type material, and as a superior material for pseudocapacitive applications. The performance of a control activated carbon has been compared with the electrodeposited carbons, and it has been shown that, when electrodeposited at low current densities, the resultant carbon performance is superior to the activated carbon.