Highly Stable and Efficient Perovskite Ferrite Electrode for Symmetrical Solid Oxide Fuel Cells.

Area of Science:

• Materials Science
• Electrochemistry
• Solid Oxide Fuel Cells

Background:

• Developing stable and efficient electrode materials is crucial for advancing solid oxide fuel cells (SOFCs).
• Symmetrical electrodes offer advantages in SOFC design by simplifying manufacturing and operation.
• Perovskite oxides are promising candidates due to their tunable properties and stability.

Purpose of the Study:

• To synthesize and characterize a novel perovskite oxide, Sm_0.8Sr_0.2Fe_0.8Ti_0.15Ru_0.05O_3-δ (SSFTR), for symmetrical SOFC electrodes.
• To investigate the performance enhancement of SSFTR-based symmetrical electrodes by introducing A-site deficiency.
• To explore the mechanism of in situ nanoparticle exsolution for improved electrocatalytic activity.

Main Methods:

• Synthesis of perovskite oxide powders with specific compositions.
• Fabrication of electrolyte-supported symmetrical cells using Sm_0.2Ce_0.8O_1.9 (SDC) electrolytes and SSFTR electrodes.
• Electrochemical performance testing, including power density measurements in a hydrogen atmosphere at 800 °C.
• Analysis of electrode stability under reducing and oxidizing conditions, and redox/thermal cycling.

Main Results:

• The synthesized SSFTR exhibits excellent stability in both reducing and oxidizing environments, along with good redox and thermal cycle stability.
• The symmetrical cell with SSFTR electrodes achieved a peak power density of 271 mW·cm^-2 at 800 °C in wet H₂.
• An A-site-deficient perovskite oxide (Sm_0.7Sr_0.2Fe_0.8Ti_0.15Ru_0.05O_3-δ) electrode demonstrated a significantly improved peak power density of 417 mW·cm^-2.
• In situ exsolution of Ru nanoparticles on the surface of the A-site-deficient electrode was observed, enhancing electrocatalytic activity.

Conclusions:

• The novel perovskite oxide SSFTR is a promising symmetrical electrode material for SOFCs, offering high stability.
• A-site deficiency in the perovskite structure effectively promotes the exsolution of catalytically active nanoparticles, leading to enhanced electrochemical performance.
• The strategy of in situ nanoparticle exsolution on electrode surfaces presents a viable approach for developing advanced electrode materials for SOFCs and other electrochemical systems.