Carbon Surface Characteristics after Electrochemical Oxidation in a Direct Carbon Fuel Cell Using a Single Carbon Pellet and Molten Carbonates

Abstract

This study investigates carbon surface characteristics after discharge in a direct carbon fuel cell using molten carbonates. In the experiment, the top surface of a single carbon pellet is pressed on the Au electrode submerged in molten carbonates and discharge is started at a constant current. First, the effect of the press force of the carbon pellet on voltage was investigated. With a decreasing press force, voltage reduction was observed at a high current, whereas the voltage remained constant at a low current. Then, after the pellet was washed, its top and side surfaces after discharge were observed and analyzed. In Auger electron spectroscopy spectra, Na peaks were not detected on the carbon surface after discharge, indicating that the washing of the pellet was sufficient to remove the carbonates. On the top surface that was in contact with the electrode, surface roughness parameters decreased after discharge, indicating that the surface became smooth after discharge. In addition, changes in surface ...