Zn BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ

1828 40 12 12 JOURNAL OF THE CHINESE CERAMIC SOCIETY Vol. 40 No. 12 December 2012 Zn BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ 1,2 1,2 2 2 2 (1. 232001 2. 232001) (SOFC) BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ (BZPY) BaZr 0.7 Pr 0.1 Y 0.16 Zn 0.04 O 3 δ (BZPYZn) Zn X BZPYZn 1 100 5 h ( 1 300 1 400 ) BZPYZn 1 350 5 h BZPYZn 97.3% 500 800 10 3 10 2 S/cm 1 000 9.2 10 6 /K (Ni) BZPYZn SOFC TM911.4 A 0454 5648(2012)12 1828 07 2012 11 29 10:09:55 http://www.cnki.net/kcms/detail/11.2310.tq.20121129.1009.201212.1828_005.html Preparation and Properties of Zn Doped BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ Proton-Conducting Used for Solid Electrolytes Oxide Fuel Cells GU Qingwen 1,2 WANG Xiaolian 1,2 DING Yanzhi 2 LIN Bin 2 CHEN Yonghong 2 (1. School of Chemical Engineering, Anhui University of Science and Technology, Huainan 232001, Anhui, China; 2. Anhui Key Laboratory of Low Temperature Co-fired Materials; Department of Chemistry and Engineering, Huainan Normal University, Huainan 232001, Anhui, China) Abstract: BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ (BZPY) and BaZr 0.7 Pr 0.1 Y 0.16 Zn 0.04 O 3 δ (BZPYZn) proton-conducting solid oxide fuel cells (SOFC) electrolytes were synthesized by a citrate nitrate combustion method. The influence of Zn doped on the sintering, coefficient of thermal expansion (TEC) and electrical properties of sample were investigated. The phase and microstructure of the sintered samples were characterized by X-ray diffraction and scanning electron microscope, respectively. The results showed that BZPYZn exhibits a single perovskite structure after the calcination at 1 100 for 5 h. With increasing of sintering temperatures (from 1 300 to 1 400 ), the grain size of BZPYZn ceramic sample increases, and porosity decreases. The high relative density of 97.3% is obtained for the BZPYZn sample sintered at 1 350 for 5 h. The BZPYZn sample exhibit a high ionic conductivity (10 3 to 10 2 S/cm) at 500 800. The average TEC of the BZPYZn is 9.2 10 6 /K from room temperature up to 1 000, which fits well with those of electrode materials (e.g. Ni). It is indicated that BZPYZn is a promising candidate as a stable and easily sintered electrolyte for intermediatetemperature SOFC. Key works: intermediate-temperature solid oxide fuel cell; proton conducting; electrolyte; zinc dopant; conductivity (solid oxide fuel cells SOFCs) 2012 07 14 2012 09 13 (1206c0805038) (51102107) (2010A03203) (1987 ) (1962 ) Received date: 2012 07 14. Revised date: 2012 09 13. First author: GU Qingwen (1987 ), male, Master candidate. E-mail: guqingwen1987@163.com Correspondent author: CHEN Yonghong (1962 ), male, Professor. E-mail: chenyh@hnnu.edu.cn

40 12 Zn BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ 1829 [1 2] SOFCs ( ) [3] SOFC (600 800 ) (IT-SOFC) [4 7] [8] Y ZrO 2 (YSZ) Gd CeO 2 (GDC) Sm CeO 2 (SDC) SOFC SOFC [9 14] SOFC SrCeO 3 BaCeO 3 CaZrO 3 BaZrO 3 LnScO 3 (Ln = La Nd Sm Gd) [15] (1 700 ) [16] Fabbri [17] Pr BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ (BZPY) 1 500 8 h 1.7 μm BZPY (600 10 2 S/cm) BZPY [18] Babilo [19] Tao [10] Zn Y Zr BaCeO 3 Zn BaCeO 3 CO 2 H 2 O BaZr 0.7 Pr 0.1 Y 0.16 Zn 0.04 O 3 δ (BZPYZn) Zn 1 1.1 Ba(NO 3 ) 2 ( ) Zr(NO 3 ) 4 5H 2 O Pr(NO 3 ) 3 6H 2 O Y(NO 3 ) 3 6H 2 O Zn(NO 3 ) 2 ( ) (C 6 H 6 0 7 H 2 O)( ) ( ) (NH 3 H 2 O)( ) ( ) ( ) 1.2 1.2.1 BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ (BZPY) BaZr 0.7 Pr 0.1 Y 0.16 Zn 0.04 O 3 δ (BZPYZn) 1 mol/l (EDTA) (ΣM Z+ ) (CA) 1:1.5 ph 7 1 150 5 h 1.2.2 200 MPa 13 mm 1 2 mm ( 1 300 1 350 1 400 ) 2 /min 5 h BZPYZn 200 MPa (40 mm 5mm 2 mm) 1 350 5 h 1.3 DX-2000 X Cu K α (λ = 0.154 18 nm) 40 kv 30 ma 0.03 2θ 20 70 Mettler Toledo TGA/SDTA 851 e TG DTG N 2 50 ml/min 10 /min KYKY EM-3200 Archimedes DIL-402C CHI-402C ( ) ( 3% ) Ag

1830 800 500 50 2 2.1 TG DTG 1 150 1 BZPYZn TG DTG 1 30 146 146 414 6.77% 6.73% 414 782 30.64% 782 (BaCO 3 ) CO 2 1 BZPYZn TG DTG Fig. 1 TG DTG curves for BaZr 0.7 Pr 0.1 Y 0.16 Zn 0.04 O 3 δ (BZPYZn) powder 2.2 2 BZPYZn Zn BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ (BZPY) 5 h X (XRD) 2a BZPYZn 5 h XRD 2a 1 000 XRD BaCO 3 1 100 BaCO 3 2θ=29.85 36.65 42.68 52.91 61.96 2b BZPY 5 h XRD 2b BZPY 1 150 2 5 h BZPYZn BZPY XRD Fig. 2 XRD patterns of the powders BZPYZn and BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ (BZPY) calcined at different temperatures for 5 h 5 h BaCO 3 BaCO 3 1 200 BaCO 3 2θ = 29.84 36.77 42.68 52.91 62.82 CaTiO 3 (JCPDF 00 001 0890) 2a 2b BZPYZn BZPY BZPY Y Zn Zn BZPY 100 1 200 1 100 2.3 SEM 3 BZPYZn 5 h

40 12 Zn BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ 1831 1 350 5 h 2.4 BZPYZn Zn 200 Babilo [19] Tao [10] Zn 2.4 2.4.1 1 13 mm BZPYZn 5h 1 350 20% 1 5 h BZPYZn Table 1 Shrinkage of samples BZPYZn sintered at different temperatures for 5 h Temperature/ Diameter/ mm Sample wafer 1 Sample wafer 2 Shrinkage/% Diameter/ mm Shrinkage/% 1 300 10.557 18.79 10.631 18.22 1 350 10.371 20.22 10.408 19.94 1 400 10.367 20.25 10.348 20.40 Note: Before sintering, size of BZPYZn sample wafer is 13 mm in diameter and 1 2 mm thick. Sample wafer 1 and sample wafer 2 represent two samples sintered at different temperatures for 5 h. 3 5 h BZPYZn SEM Fig. 3 SEM micrographs of fractured surface of BZPYZn sintered at different temperatures for 5 h SEM 3 1 300 5 h 2.5 5.0 μm 2 1 350 5 h 1 400 2.4.2 2 BZPYZn 5 h 2 1 300 1 350 95.2% 97.3% 1 400 97.8% 1 350 5 h 2 2.5 4 5 1 300 1 350 5 h BZPYZn H 2 Arrhenius 500 800 4a 5a BZPYZn H 2 1 350 1 300

1832 Table 2 2 5 h BZPYZn Relative density and porosity of samples BZPYZn sintered at different temperatures for 5 h Temperature/ Volume density/(g cm 3 ) Theoretical density/(g cm 3 ) Relative density/% Total porosity/% 1 300 4.106 4.355 95.2 5.718 1 350 4.218 4.355 97.3 3.146 1 400 4.253 4.355 97.8 2.342 4 BZPYZn (σ) (T) Arrhenius Fig. 4 Temperature dependence of the electrical conductivity (σ) and Arrhenius curves of electrical conductivity of BZPYZn in air 5 BZPYZn (σ) Arrhenius Fig. 5 Temperature dependence of the electrical conductivity (σ) and Arrhenius curves of electrical conductivity of BZPYZn in wet H 2 1 350 5 h BZPYZn 500 3.86 10 4 S/cm 800 1.62 10 2 S/cm ( 4a) H 2 1 350 5 h BZPYZn 500 1.016 10 3 S/cm 800 8.2 10 3 S/cm ( 5a) H 2 4b 5b H 2 BZPYZn Arrhenius ln(σt) = E a /(RT) + lna (1) A T

40 12 Zn BaZr 0.7 Pr 0.1 Y 0.2 O 3 δ 1833 R E a 4b 5b 700 BZPYZn ln(σt) 1/T [20] Arrhenius 1 350 1 300 74.61 kj/mol 69.04 kj/mol 1 350 1 300 52.49 kj/mol 49.05 kj/mol 700 ln(σt) (500 600 ) H 2 600 800 '' 1 i VO + O2 OO + 2h (2) 2 O O V '' O h i H 2 '' + V + H O(g) O + 2H (3) O 2 O i 2h + H (g) 2H + 2 (4) H 2 [21] BZPYZn [17] 2.6 6 1 400 5 h BZPYZn 1 000 6 L L0 dl α l = = (4) TL TL 0 0 L L 0 BZPYZn (TEC) 9.2 10 6 /K (samarium doped ceria SDC)(TEC = 12.19 10 6 /K) (La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3 δ LSGM)(TEC = 11.5 10 6 /K) 6 BZPYZn Fig. 6 Thermal expansion coefficient curve of BZPYZn samples L 0 Length of the samples at room temperature; ΔL Under testing temperature, length of the sample relative to the added value of L 0. TEC BZPYZn TEC 9.2 10 6 /K SOFC Ni TEC TEC [22] BZPYZn SOFC 3 1) BZPYZn 1 300 1 350 95.2% 97.3% 2) BZPYZn 1 100 5 h 3) 1 000 BZPYZn TEC 9.2 10 6 /K TEC 4) Zn BZPY Zn BZPY SOFC 500 800 [1],,,.

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