Investigation of Cathode Dissolution in Molten Carbonate Fuel Cell

Abstract

The dissolution of the cathode (in-site type NiO) in co-flow type molten carbonate fuel cells (MCFC) was investigated. The anode was made of Ni-10% Cr powder, and the electrolyte tile consisted of LiAlO₂ and carbonate (Li/K=62/38) powder. These components were manufactured by a doctor-brade process. These cells were operated several times (500-4000h) at 650°C. The amount of dissolved Ni was estimated by chemical analysis. Deposited Ni particles were observed in the tile by the characteristic X-ray technique. These particles had two types of shape (grain and column). The content of Ni in the tile was higher near the gas inlet than that near the outlet. The dissolution rate of Ni depended on the CO₂ partial pressure in cathode gas. The higher dissolution rate was observed at low er temperatures. This tendency might be caused by the equilibrium solubility of NiO in the carbonate. It is supposed that the fraction occupied by carbonate in the cathode′s pore had influences the NiO dissolution rate.