A Synergistic Three-Phase, Triple-Conducting Air Electrode for Reversible Proton-Conducting Solid Oxide Cells

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Reversible proton-conducting solid oxide cells (R-PSOCs) offer high efficiency and cost-effectiveness for energy applications.
• Air electrode material development is critical to overcoming energy loss and degradation in R-PSOCs.

Purpose of the Study:

• To develop novel triple-conducting air electrode materials for improved R-PSOC performance.
• To investigate the synergistic effects of doping on material properties and electrochemical activity.

Main Methods:

• Doping of transition and rare-earth metal ions into a proton-conducting electrolyte.
• Electrochemical analysis and theoretical calculations to evaluate material performance.
• Fabrication and testing of R-PSOCs using the developed air electrode materials.

Main Results:

• The optimized composition Ba$_{0.9}$Pr$_{0.1}$Hf$_{0.1}$Y$_{0.1}$Co$_{0.8}$O$_{3-δ}$ (BPHYC) exhibited outstanding activity and durability.
• BPHYC, a three-phase material, showed synergistic effects enhancing R-PSOC performance.
• Achieved a peak power density of 1.37 W cm$^{-2}$ (fuel cell mode) and 2.40 A cm$^{-2}$ at 1.3 V (water electrolysis mode) at 600 °C.
• Demonstrated stable operation for hundreds of hours.

Conclusions:

• The developed triple-conducting air electrode materials significantly improve R-PSOC performance.
• The synergistic effect of multiple phases in BPHYC is key to its enhanced activity and durability.
• These findings pave the way for more efficient and cost-effective electrochemical energy devices.