The formation of LiCoO2 on a NiO cathode for a molten carbonate fuel cell using electroplating

Abstract

Lithiated NiO cathode dissolution has been a major problem for the development of molten carbonate fuel cells (MCFCs). Many studies have been contributed to find new alternative cathodes; here, lithium cobalt oxide, LiCoO2, was coated onto the commonly used NiO cathode by the electroplating method and the resulting cathode showed much reduced solubility compared with that of the common nickel oxide cathode. Thin film lithium cobalt oxide was prepared by the oxidation of Co metal deposited on a nickel plate in molten (Li,K)2CO3 at 650 °C under a CO2–O2 (2 ∶ 1 vol%) atmosphere. When this coated nickel plate was oxidized, the open circuit potential (OCP) decayed gradually, indicating two well-defined potential plateaux; the oxide films produced at each potential plateau were identified by X-ray diffraction methods. The surface product at the first plateau was CoO. LiCoO2 was formed at the second OCP plateau [around −0.47 V vs. CO2–O2 (2 ∶ 1 vol%) reference electrode]. By the same method, LiCoO2 was coated onto a porous nickel cathode in order to produce a MCFC.