Preparation and Properties of PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δas Novel Oxygen Electrode for Solid Oxide Electrolysis Cells

Abstract

A novel double perovskite oxide PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF) was prepared by a sol-gel method and then characterized by X-ray diffraction. Pure PBSCF is intended as the oxygen electrode for solid oxide electrolysis cells (SOECs). Electrochemical impedance spectra and voltage-current curves of the electrolysis cell with the configuration of PBSCF/GDC/YSZ/Ni-YSZ were measured as a function of operating temperature and steam concentration to characterize the electrolysis cell performances. The current density increased from 1.445 A/cm 2 at 700 o C to 1.735 A/cm 2 at 800 o C with 90 vol% absolute humidity (AH) under an applied electrolysis voltage of 2V. The polarization resistance was 0.124Ω/cm 2 at 800 o C. The hydrogen generation rate of the cell can be up to 978 mL/ (cm 2 •h) at 800 o C calculated from the Faraday's law. Further, the electrolysis cell showed very stable performance during a 120 h long term electrolysis testing, indicating that PBSCF can be a very promising candidate material for the oxygen electrode of SOECs.

Identifying the Origin of the Limiting Process in a Double Perovskite PrBa0.5Sr0.5Co1.5Fe0.5O5+δ Thin-Film Electrode for Solid Oxide Fuel Cells

“…16 In addition, PBSCF has shown promising application in the reversible operation of an SOFC as an electrolysis cell. 17 In general, multiple processes occur at the triple phase boundary (TPB) of the cathode, electrolyte, and air, which may include gas-phase diffusion, surface reaction, oxygen incorporation into the bulk lattice, and its transport. Thus, it is difficult to ascribe the electrode impedance to one limiting process.…”

“…This material was further tested as a composite with Ce 0.9 Gd 0.1 O 1.95 (GDC) and as a core–shell electrode with La 2 NiO 4+δ . In addition, PBSCF has shown promising application in the reversible operation of an SOFC as an electrolysis cell …”