Effect of NiO addition on oxygen reduction reaction at lanthanum strontium cobalt ferrite cathode for solid oxide fuel cell. (19th April 2018)

• Record Type: Journal Article
• Authors: Nadeem, Mubashar; Hu, Bobing; Xia, Changrong
• Is Part Of: International journal of hydrogen energy. Volume 43:Number 16(2018)
• Page Start: 8079
• Page End: 8087
• Publication Date: 2018-04-19
• Subjects: Solid oxide fuel cell -- Lanthanum strontium cobalt ferrite -- Oxygen reduction reaction -- Interfacial polarization resistance -- NiO; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.03.053
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Lanthanum strontium cobalt ferrite( LSCF), a perovskite's family member, has gained much attention as the electrocatalyst for the oxygen reduction reaction (ORR) in intermediate temperature solid oxide fuel cells. However, it still needs a strategy to improve its catalytic activity. In this work, NiO is primarily investigated as a possible synergistic catalyst for ORR on the LSCF surface. The effect of NiO particles on the effective oxygen chemical surface exchange coefficient is revealed with the electrical conductivity relaxation (ECR) technique. At 800 °C, the coefficient is increased from 3.48 × 10 −5 to 6.65 × 10 −5 cm s −1 and 6.9 × 10 −4 cm s −1 when NiO particles are deposited using the sputter and drop coating methods, respectively. Adding 5 wt % NiO to LSCF reduces the area specific interfacial polarization resistance, for example from 0.108 to 0.082 Ω cm 2 at 700 °C, as demonstrated by impedance spectroscopy on symmetric cells using samaria-doped ceria as the electrolyte. Adding NiO can also improve the performance of anode supported button cells, increasing the peak power density from 0.731 to 1.031 W cm −2 at 800 °C. On the whole, the increased oxygen surface exchange rate together with the reduced electrode resistance and improved power density, exhibit that NiO is a potential additive to enhance the LSCF catalytic activity. Highlights: NiO is used as synergistic catalyst for ORR at LSCF cathode for SOFC. NiO particles accelerated the ORR kinetics by a factor ∼20. Enhanced kinetics is attributed to LSCF-NiO-gas three phase boundaries. The reduced resistance of LSCF is related to oxygen surface process. The LSCF-NiO composite cathode showed improved power density.