Molten carbonate fuel cell performance under different cathode conditions

Odemondo, V.; Dellepiane, S.; Bampi, R.; Capobianco, P.

doi:10.1007/s10800-009-9894-2

Cited by 3 publications

(2 citation statements)

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“…In Fig. [17][18][19] The highly electrically conductive Ag (10 4 S/ cm at 600 C, bulk Ag) (Ref. At all the operating temperatures, R charge transfer of the Ag-coated cathode was lower than that of the uncoated cathode.…”

Section: Resultsmentioning

confidence: 98%

“…The ratedetermining step of the oxygen reduction reaction in the cathode is known as the reduction step of the superoxide ion or peroxide ion in carbonate melts of the electrode receiving an electron transferred from the electrode. [17][18][19] The highly electrically conductive Ag (10 4 S/ cm at 600 C, bulk Ag) (Ref. 20) may have promoted the rate-determining step of the oxygen reduction reaction and reduced the cathode polarization.…”

Section: Resultsmentioning

confidence: 99%

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An Ag-Coated NiO Cathode for MCFCs Operating at Low Temperatures

Song

Kang

Han

et al. 2011

J. Electrochem. Soc.

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To increase the lifetime of molten carbonate fuel cell (MCFC) stacks, a reduction of the operating temperature is needed without decreasing the cell performance. In this study, a Ag coating on a conventional NiO cathode material of MCFC was carried out to enhance the cathode performance at the relatively low operating temperature of 600 C. Ag is a material applicable to cathodes for MCFCs because Ag has good catalytic activity for oxygen adsorption and dissociation and high electrical conductivity. The modified cathode was prepared by a vacuum suction method using a nanosized Ag sol suspension, and Ag particles were dispersed homogenously on the surface of a porous Ni plate. After the Ag coating, the cell performance was enhanced significantly from 0.76 to 0.80 V at a 150 mA/cm 2 current density at 600 C. The electrochemical impedance spectra show that the reduction of the charge transfer resistance is the main reason for the improvement of the cell performance after the Ag coating.Because molten carbonate fuel cells (MCFCs) are expected to penetrate into the market in the near future, their lifetime becomes an important factor to consider. The lifetime target in the market is considered as longer than 40,000 h with a voltage decay rate of less than 10% after 40,000 h of operation. [1][2][3] The lifetime of MCFCs is considered to be closely related to the operating temperature. Generally, high operating temperatures reduce polarization loss in the electrodes, especially in the cathode, and improve the electrolyte ionic conductivity, which results in a high cell performance. 4 Although the increase in operating temperature leads to higher cell performance, it accelerates the degradation of the electrodes and matrix materials, and it causes the loss of electrolytes. 5 This degradation of the MCFC components shortens the lifetime of the MCFC stacks. Thus, many research groups have studied the effect of the operating temperature on the lifetime and performance of MCFCs. Morita et al. 3 continuously operated two bench-scale cells at 600 C for 66,000 h and 650 C for 33,000 h, respectively. When comparing the results of the 650 C-33,000-h operation and those of the 600 C-66,000-h operation, it is clear that it is necessary to suppress the operating temperature of the MCFC as much as possible to achieve a lifetime over 40,000 h.To lower the operating temperature of MCFCs without a loss in performance, the electrode performance should be improved because the cell performance, in many cases, is determined by the electrode performance. In MCFCs, cathode polarization is known to be larger than that of the anode; thus, the improvement of the cathode performance, in particular, is necessary to operate the MCFC at a lower temperature.In view of the enhancement of cell performance as an improvement of the polarization of the cathode reaction, Ag is a good candidate for the cathode materials. Ag is a good electronic conductor and has been widely investigated as a catalyst for oxygen adsorption, dissociation and diffusion. 6-14 Th...

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%