The effect of group IIIA oxides on the oxygen reduction reaction at cathodes for intermediate-temperature solid oxide fuel cells. (15th May 2020)

• Record Type: Journal Article
• Authors: Nadeem, Mubashar; Wan, Yanhong; Xia, Changrong
• Is Part Of: Composites. Number 189(2020)
• Publication Date: 2020-05-15
• Subjects: Solid oxide fuel cell -- Oxygen reduction reaction -- Lanthanum strontium cobalt ferrite -- Lanthanum strontium ferrite -- Distribution of relaxation time -- Electrical conductivity relaxation; Composite materials -- Periodicals; Materials science -- Periodicals; Composite materials; Periodicals; Electronic journals; 620.118
• DOI: 10.1016/j.compositesb.2020.107924
• Languages: English
• ISSNs: 1359-8368

Abstract

Abstract: This study investigates the effect of B2 O3, Al2 O3, Ga2 O3 and In2 O3, belonging to group IIIA, on the oxygen reduction reaction (ORR) at typical electrocatalysts, lanthanum strontium cobalt ferrite (LSCF) and lanthanum strontium ferrite (LSF), for intermediate temperature solid oxide fuel cells (SOFCs). Amongst these oxides, In2 O3 significantly enhances the electrochemical performance by improving ORR as determined by AC impedance spectroscopy using symmetrical cells comprising samaria-doped ceria as the electrolyte. When 13.73 and 7.88 wt % In2 O3 is impregnated into the porous LSCF and LSF electrodes, at 650 °C, the area specific interfacial polarization resistance (ASR) decreases from 0.41 to 0.27 Ω cm 2 and from 0.99 to 0.39 Ω cm 2, respectively. The distribution of relaxation time analysis suggests that In2 O3 efficiently accelerates the charge transfer and oxygen incorporation processes. The chemical oxygen surface exchange coefficients are greatly increased by In2 O3 deposition as demonstrated with the electrical conductivity relaxation technique. For example, at 800 °C, the deposition of 0.202 mg cm −2 In2 O3 particles increases the coefficient from 4.53 × 10 −5 to 2.81 × 10 −4 cm s −1 and from 2.39 × 10 −5 to 9.3 × 10 −5 cm s −1 for LSCF and LSF, respectively. Highlights: Effect of group IIIA oxides on the ORR at LSCF and LSF electrocatalysts for SOFC. Indium oxide significantly improves the ORR kinetics. Indium oxide decreases the area specific resistance of the electrode. DRT analysis reveals accelerated charge transfer and oxygen incorporation processes upon indium oxide addition.