PbO effect on the oxygen reduction reaction in intermediate-temperature solid oxide fuel cell. (21st September 2020)

• Record Type: Journal Article
• Authors: Nadeem, Mubashar; Li, Yihang; Bouwmeester, Henny J.M.; Xia, Changrong
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 46(2020)
• Page Start: 25299
• Page End: 25306
• Publication Date: 2020-09-21
• Subjects: Solid oxide fuel cell -- Oxygen reduction reaction -- Lanthanum strontium cobalt ferrite -- Lanthanum strontium ferrite -- Interfacial polarization resistance -- PbO; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.06.245
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Ag paste is often used in solid oxide fuel cells (SOFCs) as the current collector. This study investigates the effect of lead oxide (PbO), which is usually present in Ag paste, on the oxygen reduction reaction (ORR) at the typical electrocatalysts, lanthanum strontium cobalt ferrite (LSCF) and lanthanum strontium ferrite (LSF), for intermediate-temperature SOFCs. The chemical oxygen surface exchange coefficients are greatly increased by the deposition of PbO particles on the LSCF and LSF bar surfaces as demonstrated by the electrical conductivity relaxation technique. For example, at 800 °C, the deposition of 0.074 mg cm −2 PbO particles increases the coefficients from 4.68 × 10 −5 to 7.2 × 10 −4 cm s −1 and from 2.62 × 10 −5 to 1.60 × 10 −4 cm s −1 for LSCF and LSF, respectively. Furthermore, the infiltration of PbO into porous LSCF and LSF electrodes significantly improves the ORR as determined with AC impedance spectroscopy using symmetrical cells comprising of samaria-doped ceria as the electrolyte. When 5.88 and 5.67 wt % PbO is infiltrated into the porous backbone of LSCF and LSF electrodes, at 650 °C, the area specific interfacial polarization resistance (ASR) is reduced from 0.26 to 0.14 Ω cm 2 and from 1.34 to 0.37 Ω cm 2, respectively. The distribution of relaxation time (DRT) analysis suggests that PbO efficiently accelerate the charge transfer and oxygen incorporation processes. Highlights: Effect of PbO containing Ag pastes towards the electrochemical performance of SOFCs. Lead oxide significantly improves the ORR kinetics. Lead oxide decreases the area specific resistance of the electrode. DRT analysis reveals accelerated charge transfer and oxygen incorporation process.