The electrochemical deposition and re-oxidation of solid carbon were studied in CO3(2-) ion-containing molten salts (e.g. CaCl2-CaCO3-LiCl-KCl and Li2CO3-K2CO3) at temperatures between 500 and 800 °C under Ar, CO2 or N2-CO2 atmospheres. The electrode reactions were investigated by thermodynamic analysis, cyclic voltammetry and chronopotentiometry in a three-electrode cell under various conditio...