The effect of nanolayer of cathode on cell performance in Molten Carbonate Fuel Cells

Fuel cell is one of the best solutions for distributed powder for the city. Among many types of fuel cells, molten carbonate fuel cell (MCFC) operated at high temperature (650 oC) has been studied intensively due to no... [ view full abstract ]

Fuel cell is one of the best solutions for distributed powder for the city. Among many types of fuel cells, molten carbonate fuel cell (MCFC) operated at high temperature (650 ^oC) has been studied intensively due to no necessity of using expensive noble metal catallysts and variety of fuel selection. However, MCFC has the relatively lower cell performance than that of SOFC(solid oxide fuel cell). The oxygen reduction reaction (ORR) in cathode is considered much slower that the hydrogen oxidation reation in anode. To enhance the cell performance of MCFC, new cathode has to be developed.

 In the present study, the effect of nano NiO layer on cathode on cell perfoance in MCFC is examined. To increase cell performance, increasing the active area in electrode is very important.  However, the attempt on increase reaction layer in electrode have been little in MCFC area yet.

For the formation of reaction layer, nano lithiated NiO powder was prepared as following method. the nano Ni powder (70 nm size, 10m²/g surface area) and lithium nitrate was mixed by 1:1 mole fraction in mortar, and then was heated at 650 ^oC 3hr in air atmosphere. The surface area of as-prepared nano lithiated NiO powder is 7m²/g. The ORR can occur in whole surface area of applied nano lithiated NiO layer, the area of reaction layer is about 12m²/g when coating nano lithiated NiO of 10wt%. The surface area of conventional lithiated NiO electrode used as cathode is 0.48 m²/g. the thin layer were prepared after nano lithiated NiO coating. the thicknesses of the thin layers at 5wt% coating and 15wt% coating are 24 and 78 um, respectively. The cell performance of cell with nano lithated NiO is 0.86V at 620 ^oC. It is very high value as comparing that of uncoated cathode, 0.78V. As shown in EIS results, the charge transfer resistance were reduced dramatically after nano lithiated NiO coating. It shows that enlarging reaction area in cathod via the formation of reaction layer by coating nano lithiated NiO powder certainly enhances the cell performance.