Electrodeposition of Carbon from High Temperature Carbonate Melts

Abstract

The storage and release of electrical energy is vital to the functioning of many necessities of modern life including portable electronic devices, power tools, and automobiles. In the face of our ever-increasing need for better energy storage devices, it is desirable that we continue to investigate superior materials for use in battery and supercapacitor devices. It has long been known that carbons may be produced through the electrolytic reduction of molten carbonates, with the mechanism of this reduction being thought to proceed by way of Eqn 1 [1], i.e.; CO3 2- + 4e- ---> C+3O2- …(1) For this research carbons were prepared by varying the electrodeposition parameters around a standard set of conditions (Li2CO3-Na2CO3-K2CO3 electrolyte, 0.25 A/cm2 current density, graphite substrate, 600°C). The research of this group indicates at this point that there exist reproducible patterns in the properties of our carbons based on most of these variables, with the primary result of the research linking decreased current densities, decreased temperatures, and every electrolyte except Li2CO3-Na2CO3, but not substrate to any major degree, to increased capacitive performance. 1. Le Van, K., et al., Electrochemical formation of carbon nano-powders with various porosities in molten alkali carbonates. Electrochimica Acta, 2009. 54(19): p. 4566-4573.