SmBaCo 2 O 5+δ (SBCO) Sm 0.2 Ce 0.8 O 1.9 (SDC) 3:2

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1 JOURNAL OF THE CHINESE CERAMIC SOCIETY 2012 Vol. 40 No. 10 October 2012 SmBaCo 2 O 5+δ Sm 0.2 Ce 0.8 O 1.9 1, ( ) SmBaCo 2 O 5+δ (SBCO) Sm 0.2 Ce 0.8 O 1.9 (SDC) 3:2 X (Ni-SDC SDC SBCO-SDC) SBCO SDC S/cm SDC Ω cm 2 H 2 ( 3% ) V 640 mw/cm 2 SBCO-SDC TM911.4 A (2012) :48:31 Electrochemical Performance of SmBaCo 2 O 5+δ Sm 0.2 Ce 0.8 O 1.9 as Composite-Cathode for Intermediate Temperature Solid Oxide Fuel Cells WANG Xiaolian 1,2 DING Yanzhi 2 LIN Bin 2 LU Xiaoyong 2 CHEN Yonghong 2 (1. School of Chemical Engineering, Anhui University of Science and Technology, Huainan , Anhui, China; 2. Anhui Key Laboratory of Low Temperature Co-fired Materials; Department of Chemistry and Engineering, Huainan Normal University, Huainan , Anhui, China) Abstract: The cathode powder of double perovskites-type SmBaCo 2 O 5+δ (SBCO) and electrolyte powder of fluorite-structure Sm 0.2 Ce 0.8 O 1.9 (SDC) were synthesized by a citric acid-nitrates self-propagating combustion method. The composite-cathode was obtained by mixing and grinding the SBCO and SDC powders at a mass ratio of 3:2. The chemical compatibility, electrical conductivity and thermal expansion coefficient (TEC) of the composite-cathode (SBCO-SDC) were characterized by X-ray diffraction, direct current four-terminal method and thermal dilatometry, respectively. An anode-supporting fuel cell of Ni-SDC SDC SBCO-SDC was fabricated and the performance of the cell was analyzed. The cross-section microstructure and polarization of the cell were investigated using a scanning electron microscope (SEM) and AC impedance spectroscopy. The results indicate that there are no interactions between SBCO and SDC at The electrical conductivity of the SBCO-SDC composite-cathode reached to S/cm at The addition of SDC decreased the TEC of the composite-cathode. The single cell has an ideal microstructure and a good interface among anode, electrolyte and cathode. The polarization resistance of the electrodes was Ω cm 2 at 650. The cell with an open-circuit potential of 0.77 V and a maximum output power density of 640 mw/cm 2 was obtained when the humidified (about 3% H 2 O) hydrogen as a fuel and air as oxidant were used at 650. It was demonstrated that the SBCO-SDC composite-cathode could be used as a potential candidate cathode for intermediate temperature solid oxide fuel cell. Key works: composite-cathode; intermediate temperature solid oxide fuel cell; electrochemical performance; polarization ( ) (KJ2008A150) (2010A03203) (1986 ) (1962 ) Received date: Revised date: First author: WANG Xiaolian (1986 ), female, Master candidate. Correspondent author: CHEN Yonghong (1962 ), male, Professor. chenyh@hnnu.edu.cn

2 40 10 SmBaCo 2 O 5+δ Sm 0.2 Ce 0.8 O (solid oxide fuel cell SOFC) [1] ( ) SOFC SOFC ( ) SOFC (Intermediate temperature IT-SOFC) [2] (La 1 x Sr x MnO 3 δ LSM) [3] SOFC [4 6] (thermal expansion coefficient TEC) TEC 112 LnBaCo 2 O 5+δ (Ln = Pr, Gd, Sm, Y, Nd LBCO) IT-SOFC [7 11] TEC IT-SOFC Kim [12] Ln 3+ LnBaCo 2 O 5+δ (Ln +3 ) Ln 3+ TEC Sm 3+ LnBaCo 2 O 5+δ IT-SOFC (SmBaCo 2 O 5+δ SBCO) Sm 0.2 Ce 0.8 O 1.9 (SDC) SBCO-SDC SDC SBCO-SDC SDC NiO-SDC [Sm(NO 3 ) 3 6H 2 O](AR ) Ba(NO 3 ) 2 [Co(NO 3 ) 2 6H 2 O] [Ce(NO 3 ) 2 6H 2 O] AR ( ) 1 mol/dm 3 (EDTA) 1.2 SBCO n(sm): n(ba):n(co) = 1:1:2 Sm(NO 3 ) 3 Ba(NO 3 ) 2 Co(NO 3 ) (Σn Z+ M ) (n CA ) 1: h SBCO SDC h SBCO SDC 3:2 SBCO (200 MPa) (40 mm 5 mm 2 mm) h 1.3 NiO ( ) SDC 3:2:1 5 h 200 MPa SDC 13 mm h 3:2 SBCO SDC (SBCO- SDC) 5% h

3 DX-2000 X ( ) SBCO SDC Cu K α λ = nm 40.0 kv 30 ma θ DIL 402C ( Netzsch ) ( ) 50 ml/min 5 /min Al 2 O 3 ( 3% ) (Ni-SDC SDC SBCO-SDC) CHI 604B ( ) KYKY EM-3200 ( ) [13 14] SBCO SDC 1:1 SBCO SDC X (XRD) 1 SBCO h ( 1 2 JCPDS ) [7] SBCO 100 SDC h ( 1 1 JCPDS ) h XRD SBCO SDC ( 1 3) SBCO SDC SOFC 2.2 SBCO SBCO-SDC h Archimedes 87.6% 95.5% 2 1 SBCO SDC SBCO-SDC XRD Fig. 1 XRD patterns of SBCO, SDC and SBCO-SDC SBCO [7] Co 4+ Co 3+ [15] SBCO SBCO SDC ( 40%) SDC SBCO SDC SDC SBCO SDC 234 S/cm SOFC 100 S/cm [16] SBCO SDC h SBCO-SDC

4 40 10 SmBaCo 2 O 5+δ Sm 0.2 Ce 0.8 O TEC TEC SBCO Ni-SDC SDC SBCO-SDC [ (I V) (I P) ] 1 (OCV) 2 SBCO SBCO-SDC (σ) Fig. 2 Temperature dependence of conductivity (σ) for SBCO and SBCO-SDC in air 4 Ni-SDC SDC SBCO-SDC Fig. 4 Performance of the cell fabrication with Ni-SDC SDC SBCO-SDC 1 Ni-SDC SDC SBCO-SDC Table 1 Performance of the cell fabrication with Ni-SDC SDC SBCO-SDC Temperature/ OCV/V P/(mW cm 2 ) SBCO-SDC SBCO SDC NiO-SDC Fig. 3 Thermal expansion curves of SBCO-SDC, SBCO, SDC and NiO-SDC ΔL/L 0 Change in lengh of the samples. ( ) SBCO h SDC NiO-SDC 3 4 SBCO /K SBCO-SDC /K SDC /K NiO-SDC /K SBCO SBCO-SDC TEC TEC SBCO TEC 10% OCV Open circult voltage; P Power density. 4 4 I V [17] (open circult voltage OCV) V 0.77 V OCV 1.0 V SDC Ce mw/cm 2 [18] LnBaCo 2 O 5+x SDC ( mw/cm 2 )

5 SEM 5 Ni-SDC SDC SBCO-SDC SEM μm μm NiO Ni 5 Ni-SDC SDC SBCO-SDC SEM Fig. 5 SEM photographs of cross-sections for Ni-SDC SDC SBCO-SDC single cell after characterization 2.6 ( ) IT-SOFC SBCO-SDC Ni-SDC SDC SBCO-SDC Ω cm Ω cm 2 6 Ni-SDC SDC SBCO-SDC Fig. 6 Impedance spectra of the cell for Ni-SDC SDC SBCO- SDC ( ) 5 SDC Suzuki [19] ( ) Ni 7 (R t ) (R p ) (R o ) (R p /R t ) R p 0.16 Ω cm 2 R o 0.39 Ω cm R p R o 0.42 Ω cm Ω cm % % IT-SOFC

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