Effects of oxygen reduction and hydration on performance of protonic ceramic fuel cells in hydrocarbon fuels

Improving the Catalytic Activity of (Ba0.95La0.05)(Fe0.8Zn0.2)O3−δ Protonic Ceramic Fuel Cell Cathodes by Cation Substitution

“…7,24 In PCFCs, it has been reported that R 1 /C 1 and R 2 /C 2 at frequencies above 100 Hz represent the electrochemical reactions at the anode, and the other two R/C components of R 3 /C 3 and R 4 /C 4 are related to the charge transfer reaction at the TPB and the adsorption-dissociation reaction at the surface of the cathode, respectively. 6,7,17,18 As shown in Fig. 8, the impedance spectra fitted by equivalent circuits (open symbols) agreed well with the impedance spectra of the BLFZ cell measured in H 2 fuel at 600 °C.…”

“…In our previous work, we found that the cathode performance of BLFZ could be improved by adding LSC to a BLFZ-BCZY composite cathode to make a triple-component composite cathode. 18 The total cathode ASR of this triple-component composite cathode composed of LSC, BLFZ, and BCZY, calculated by the equivalent circuit models in the same way, was 0.029 and 0.041 Ωcm 2 for H 2 and CH 4 fuels, respectively. These values are slightly smaller than those of the BLCFZ cells.…”

“…It is known that the impedance spectra of PCFCs in the lowfrequency region (below 100 Hz) are related to elementary electrochemical reactions at the cathode, such as oxygen incorporation into the lattice, the oxygen reduction reaction, and oxygen adsorption and dissociation reactions. 7,17,18 This implies that the improved BLCFZ fuel cell performance was caused by the improvement in the cathode performance, and the cobalt doping into BLFZ enhanced the catalytic activity of the electrochemical reactions involving oxygen molecules. This can be attributed to the multivalent oxidation state of the cobalt cations in the BLCFZ perovskite structure, which was mentioned in the analysis of the XRD results.…”

“…This difference can be attributed to the lower final calcination temperature and smaller particle sizes of the components on the surface of the triple-component composite cathode because the LSC in the triplecomponent composite cathode was calcined at 700 °C, whereas BLCFZ was calcined at 850 °C. 18 The reduction in the particle size of BLCFZ and its effects on the cathode performance will be investigated in future work.…”

“…17 We have reported that the poor catalytic activity of BLFZ can be improved by fabricating a triple-component composite cathode, in which catalysts such as BCFZY and (La 0.8 Sr 0.2 )CoO 3−δ (LSC) are added to the BLFZ composite cathodes as the third component. 17,18 As mentioned above, Co cations have been doped into many novel PCFC cathodes with perovskite structures to improve the catalytic activity. Therefore, in this study, the composition of BLFZ was modified by Co doping to improve its catalytic activity, and the performance of the resulting cathode was compared with that of a triple-component composite cathode.…”