Performance of the Composite Cathode Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ce0.9Gd0.1O2-δ for Medium-low Temperature Solid Oxide Fuel Cell

doi:10.15541/jim20170232

Abstract

Abstract:

Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-_δ(BSCF) powder was prepared via Sol-Gel method. Porous BSCF-xGDC(x= 30wt%, 40wt%, 50wt%) composite cathodes were prepared via wrapping BSCF powders with Ce_0.9Gd_0.1O_2-_δ (GDC) sol. The phase composition of the composite cathodes, the morphology of the cross section of the cell, as well as the BSCF particles coated with GDC were characterized with X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy, respectively. The electrochemical performances of the composite cathodes were studied by impedance spectroscopy. The effects of the amount of GDC on the electrochemical performance of the composite cathode were studied by impedance spectroscopy. All results showed that the electrochemical performance of the composite cathode greatly improved. Electrode polarization resistance of the BSCF-40GDC was the minimum, with the value of 0.397 Ω•cm² at 650℃. The maximum power density of the single cell was 0.514 W/cm²with the values of Ohmic resistance at 0.257 Ω•cm² and the polarization resistance at 0.0588 Ω•cm², by using H₂+3%H₂O as fuel and air as oxidizing gas at 650℃.

Key words: SOFC, composite cathode materials, BSCF-GDC, electrochemical performance

CLC Number:

TQ174

LUO Ling-Hong, HU Jia-Xing, CHENG Liang, XU Xu, WU Ye-Fan, LIN You-Chen. Performance of the Composite Cathode Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-_δ-Ce_0.9Gd_0.1O_2-_δ for Medium-low Temperature Solid Oxide Fuel Cell[J]. Journal of Inorganic Materials, 2018, 33(4): 441-446.

Figures/Tables 10

Fig. 1 XRD patterns of BSCF-40GDC cathode powder calcined at different temperatures

Fig. 2 TEM images of BSCF particles coated by GDC

Fig. 3 Impedance spectra for BSCF-xGDC cathode measured at 650℃

Table 1 Impendance spectra fitting results of the BSCF-xGDC cathode measured at 650℃

Sample	R/(Ω•cm²)
Sample	R₁	R₂	R₃	R_el=(R₂+R₃)/2
BSCF-30GDC	15.24	0.595	0.338	0.466
BSCF-40GDC	12.10	0.494	0.301	0.397
BSCF-50GDC	16.31	1.463	0.305	0.884

Fig. 4 Arrhenius plots of resistance of BSCF-GDC compoistes measured at temperature from 550℃ to 750℃

Fig. 5 SEM images of the fracture section for the single-cell with BSCF-40GDC cathode(a) Cross section of whole cell; (b) Cross section of the cathode

Fig. 6 I-V and I-P characteristics of the cells for different ratios of BSCF-GDC at 650℃

Fig. 7 I-V and I-P curves of BSCF-40GDC|GDC|NiO-GDC single cell at different operation temperatures

Fig. 8 Impedance spectra of the single cell for different ratios of BSCF-GDC tested at 650℃

Fig. 9 Impedance spectra of BSCF-40GDC|GDC|NiO-GDC single cell at different operation temperature

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