The Polarization of Molten Carbonate Fuel Cell Electrodes: II . Characterization by AC Impedance and Response to Current Interruption

Abstract

AC impedance and current interruption measurements have been investigated as an in situ method for characterizing rate-limiting processes in molten carbonate fuel cell porous electrodes. Analysis of the data for the fuel cell anode indicates that the anode is always under strong mass-transfer control, in the temperature range of 600-700~ Analysis of data for the cathode indicates that at 650~ the cathode is under mixed control. Charge-transfer control is approached at lower temperature (600~ and at high CO2 partial pressures. Control by mass transfer or slow homogeneous reactions (e.g.,

Performance of La0.8Sr0.2CoO3 coated NiO as cathodes for molten carbonate fuel cells

“…The impedance response shown in Fig. 8 is similar in appearance to the ones obtained by Yuh and Selman [11,12] under similar conditions. As shown in Fig.…”

“…The magnitude of the impedance loop decreased on increasing the O 2 partial pressure. This clearly indicates a positive reaction order for oxygen and is similar to the response seen for NiO [12]. In case of CO 2 , the impedance value increased with an increase in CO 2 partial pressures implying that the reaction order of CO 2 must be negative.…”

“…Nickel (Aldrich) particles were ground Journal of Power Sources 115 (2003) [12][13][14][15][16][17][18] and sieved to obtain uniform particles of size 3-5 mm. The tape casting slurry was prepared by ball milling nickel powder in water with suitable binder (PVA) and plasticizer (glycerol).…”

Analysis of a molten carbonate fuel cell: Numerical modeling and experimental validation

“…These values were found by using a value of 0.5 for the transfer coefficient (α). Another approach is given by Yuh and Selman [1,2], which has received a somewhat general acceptance because it combines a general, macro-homogeneous concept of the active reaction sites (agglomerates) with a specific micro-geometric representation of the gas transport and current conduction in the electrode. In this so-called agglomerate model, the porous electrode is divided spatially into two regions, one consisting of agglomerates of solid particles having liquid-filled micro-pores, and the other consisting of macro-pores.…”

“…In this so-called agglomerate model, the porous electrode is divided spatially into two regions, one consisting of agglomerates of solid particles having liquid-filled micro-pores, and the other consisting of macro-pores. In this approach, the cell potential is calculated by [1,2]:…”