Improved Performance of Symmetrical Solid Oxide Fuel Cells with Redox-reversible Pr0.6Sr0.4Co0.2Fe0.8O3-δ Electrodes

doi:10.15541/jim20160340

Abstract

Abstract:

Pr_0.6Sr_0.4Co_0.2Fe_0.8O_3-_δ (PSCF) and Gd_0.2Ce_0.8O_2-_δ (GDC) powders were synthesized by a citric acid- nitrates self-propagating combustion method, and La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-_δ (LSGM) electrolyte powder was prepared by conventional solid state reaction process. The LSGM-supported symmetrical solid oxide fuel cell of PSCF│GDC│LSGM│GDC│PSCF with GDC function layer was fabricated. The phase structure, chemical compatibility, polarization resistance, cross-section microstructure and the cell performance were investigated by X-ray diffraction (XRD), electrochemical impedance spectra, scanning electron microscope (SEM) and self-assembly SOFC test system, respectively. The results indicate that PSCF powder exhibits a single perovskite with cubic symmetry and a good redox reversibility. The GDC function layer dramatically improve the chemical compatibility among PSCF, LSGM in hydrogen and the cell performance. The area specific resistance (ASR) of PSCF│GDC decreased from 6.892 Ω·cm² to 0.314 Ω·cm² in hydrogen at 800℃ and the maximum power density increased from 269 mW/cm² to 463 mW/cm² using humidified hydrogen (3%H₂O) as fuel and ambient air as oxidant. The results indicate that PSCF is a promising electrode material for symmetrical solid oxide fuel cells, and GDC function layer is a potential way to enhance the long-term stability.

Key words: symmetrical solid oxide fuel cell, redox reversibility, Pr0.6Sr0.4Co0.2Fe0.8O3-δ, GDC function layer

CLC Number:

TQ174

YANG Yang, TIAN Dong, DING Yan-Zhi, LU Xiao-Yong, LIN Bin, CHEN Yong-Hong. Improved Performance of Symmetrical Solid Oxide Fuel Cells with Redox-reversible Pr_0.6Sr_0.4Co_0.2Fe_0.8O_3-_δElectrodes[J]. Journal of Inorganic Materials, 2017, 32(3): 235-240.

Figures/Tables 7

Fig. 1 XRD patterns of PSCF calcined at 1000℃ for 3 h in air (a), reduced at 800℃ for 10 h in humidified H2 (b) and calcined at 800℃ for 3 h in air (c)

Fig. 2 XRD patterns of PSCF with LSGM and GDC mixtures calcined for 10 h in different atmospheres (a) 1000℃ in air; (b) 800℃ in H2

Fig. 3 Impedance spectra of SSOFC (a) PSCF│LSGM│PSCF in air; (b) PSCF│GDC│LSGM│GDC│PSCF in air; (c) PSCF│LSGM│PSCF in H2 and (d) PSCF│GDC│LSGM│GDC│PSCF in H2

Fig. 4 Interfacial polarization resistance (Rp) obtained under open-circuit condition at different temperatures

Fig. 5 Electrochemical performance of single cell for (a) PSCF│LSGM│PSCF and (b) PSCF│GDC│LSGM│GDC│PSCF

Fig. 6 Electrochemical impedance spectra of single cells for (a) PSCF│LSGM│PSCF and (b) PSCF│GDC│LSGM│GDC│PSCF under operating condition

Fig. 7 Cross-sectional SEM images of (a) PSCF│LSGM│PSCF and (b) PSCF│GDC│LSGM│GDC│PSCF after testing

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