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Preparation and characterization of LiCoO2 and LiMg0.05Co0.95O2 thin films on porous Ni/NiO cathodes for MCFC by complex sol-gel process (CSGP)

TitoloPreparation and characterization of LiCoO2 and LiMg0.05Co0.95O2 thin films on porous Ni/NiO cathodes for MCFC by complex sol-gel process (CSGP)
Tipo di pubblicazionePresentazione a Congresso
Anno di Pubblicazione2000
AutoriLada, W., Deptula A., Sartowska B., Olczak T., Chmielewski A.G., Carewska M., Scaccia S., Simonetti E., Giorgi L., and Moreno A.
Conference NameMaterials Research Society Symposium - Proceedings
Conference LocationSan Francisco, CA
Parole chiaveAmmonia, Ascorbic acid, Cathodes, Characterization, Complex sol-gel process, Dissolution, Film preparation, Fuel cells, Lithium compounds, Mechanical properties, Microstructure, Molten Carbonate Fuel Cells, pH, Porous materials, Sol-gels, Thin films
Abstract

The major disadvantage of Ni/NiO cathodes for a Molten Carbonate Fuel Cells (MCFC) application is dissolution of NiO in K/Li electrolyte that significantly decreases the cell lifetime. Thin films of LiCoO2 or LiMg0.05Co0.95O2 were prepared on a cathode body in order to protect them against dissolution. For preparation of starting sols the Complex Sol-Gel Process (CSGP) has been applied. These sols have been prepared by adding of LiOH to aq. acetates solution of Co2+(Mg2+) with ascorbic acid and then by alkalizing them with aqueous ammonia to pH=8. The cathode plates of various dimensions (to several hundreds cm2) have been dipped in these sols and withdrawn at rate a 1.7 cm/s. Commercially sintered Ni plates were always initially oxidized by heating at various temperatures. Their microstructure and mechanical properties as a function of temperature were observed. Heat treatment should be carried out under the dead load of the ceramic plates in order to avoid their waving. The best non-folded plates were obtained by treating them for 1h at 550°C. The covered substrates were calcined for 1h at 650°C, using low heating rate 1°C/min. The presence of LiCoO2 in a deposited coating has been proved by EDS patterns. The resultant film thicknesses were measured by scanning electron microscopy (SEM) on the fractured cross-sections; they ranged from 0.5 to 2μm and depended on sol concentration and viscosity. A 350 hundred hours test in molten carbonates, proved that the cathode bodies covered with LiCoO2 are completely prevented from dissolution of Ni in a molten K/Li electrolyte. Dissolution of LiCoO2 coating was not observed as well. After treatment in a molten electrolyte SEM observations did not show any changes in microstructures and morphology of the covered cathodes.

URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-0034447185&partnerID=40&md5=0e818c1b6de63fe44bb85f5e14d2a32f
Citation KeyLada2000395