An Efficient Bifunctional Air Electrode for Reversible Protonic Ceramic Electrochemical Cells

摘要

One of the main bottlenecks that limit the performance of reversible protonic ceramic electrochemical cells (R-PCECs) is the sluggish kinetics of the oxygen reduction and evolution reactions (ORR and OER). Here, the significantly enhanced ORR and OER kinetics and stability of a conventional La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) air electrode by an efficient catalyst coating of barium cobaltite (BCO) is reported. The polarization resistance of a BCO-coated LSCF air electrode at 600 degrees C is 0.16 omega cm(2), about 30% of that of the bare LSCF air electrode under the same conditions. Further, an R-PCEC with the BCO-coated LSCF air electrode shows exceptional performance in both fuel cell (peak power density of 1.16 W cm(-2) at 600 degrees C) and electrolysis (current density of 1.80 A cm(-2) at 600 degrees C at 1.3 V) modes. The performance enhancement is attributed mainly to the facilitated rate of oxygen surface exchange.

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