Steady‐State Composition Profiles in Mixed Molten Salt Electrochemical Devices: II . Molten Carbonate Fuel Cell Analogs

Abstract

Steady-state equations, derived previously for composition gradients in battery analogs with binary mixtures of molten salts as electrolytes, have been modified to apply to molten carbonate fuel cells. Since neither of the two like-charged cations of the electrolyte reacts at the electrodes, the concentration gradient arises only from the difference in the mobilities of the two cations. Conditions of current density, electrode separation, electrolyte composition, and temperature that favor either steady state or precipitation of a solid phase are presented in parametric form. Numerical solution of the diffusion-migration equation is used to predict the development with time of the concentration gradient. The computation also simulates the variations with time of emf between anode and cathode both during current flow and during the subsequent decay on open circuit. An electrochemical method for estimation of the interdiffusion coefficient and the ion mobility ratio in a binary electrolyte is outlined.

Electrochemical Removal of H 2 S from Hot Gas Streams: Nickel/Nickel‐Sulfide Cathode Performance

“…Gas containing 10% 02 and 12% CO2 in N2 was slowly bubbled past the reference electrode so that the half-cell may be written as Au/O2, COJCO32 [14] Figures 1 and 2 show the placement of the reference in relation to the working and counterelectrodes. The reference electrode consisted of a 0.375 mm diam gold wire in contact with the carbonate tile.…”

“…The reference electrode consisted of a 0.375 mm diam gold wire in contact with the carbonate tile. Gas containing 10% 02 and 12% CO2 in N2 was slowly bubbled past the reference electrode so that the half-cell may be written as Au/O2, COJCO32 [14] Figures 1 and 2 show the placement of the reference in relation to the working and counterelectrodes.…”

Composition Gradients in Electrolyzed LiCl ‐ KCl Eutectic Melts

“…Other evidence for solid precipitation in molten salt cells also has been reported (5,(9)(10)(11). These effects would be reduced by the use of an all lithium electrolyte (12), but would not all be eliminated, because electromigrational composition gradients still are expected (2,13).…”

Electrochemical membrane separation of H2S from reducing gas streams

“…The reference electrode consisted of a 0.2-mm-diameter gold wire encased within an alumina tube in contact with the outer portion of the electrolyte tile. Gas containing 3% O,, 15% CO,, and balance N, was flown by the reference electrode providing the following known, stable half-cell reaction (Vallet and Braunstein, 1979):…”