A surface reconfiguration of a perovskite air electrode enables an active and durable reversible protonic ceramic electrochemical cell

作者：He, Fan; Liu, Dongliang; Zhang, Hua; Xu, Yangsen; Xu, Kang; Chen, Yu^*

来源：Energy Storage Materials, 2022, 53: 754-762.

DOI：10.1016/j.ensm.2022.10.009

• Air electrode
• In situ formation
• Nanoparticles
• Oxygen reduction/evolution reactions
• Reversible protonic ceramic electrochemical cells

Reversible protonic ceramic electrochemical cells (R-PCECs) are promising devices for efficient energy storage and conversion. One key technical challenge facing the development of R-PCECs is the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air electrode. Moreover, under typical operating conditions of R-PCECs, the surface of air electrodes readily interacts with the steam, causing severe cation segregations and performance degradations. Here, we report a perovskite-type air electrode with a nominal composition of Ba0.8Gd0.8Pr0.4Co2O5+delta, naturally reconfiguring to a double perovskite Ba0.8Gd0.8-xPr0.4Co2-yO5+delta (BGPC) and in situ formed GdxCoyO3-delta (GCO) nanoparticles (NPs) on the surface of BGPC. Accordingly, the GCO-coated BGPC (GCO-BGPC) electrode shows a low polarization resistance of 0.136 Omega cm(2) at 650 degrees C in a symmetrical cell in wet air (3 vol% H2O). When applied as an air electrode on a fuel electrode-supported cell, the cell demonstrates a good electrochemical performance at 650 degrees C (a peak power density of 0.909 W cm(-2) in fuel cell mode and a current density of 2.336 A cm(-2) at 1.3 V in electrolysis cell mode) while maintaining robust reversible operational stability and reasonable Faradaic efficiencies.

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