Authors: Huanxin Xiang | Fangyuan Zheng | Ning Wang | Chunmei Tang | Baoyin Yuan | Qingwen Su | Xiaohan Zhang | Yoshitaka Aoki | S. Q. Ye
Source: Small (article, 2025-12-31)
Field: Materials Science — Materials Chemistry

Significantly Enhanced Electrocatalytic Activity of Air Electrodes in Protonic Ceramic Cells by A‐Site Deficiency Engineering Hydrogen utilization and production through reversible protonic ceramic cells (PCCs) exhibit significant promise as long-term energy storage and conversion systems for renewable sources. However, inadequate intrinsic electrocatalytic activities of the air electrodes for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remain a fundamental bottleneck, severely limiting the enhancement of PCC electrochemical performance. Oxygen vacancies ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msubsup><mml:mi>V</mml:mi> <mml:mi>O</mml:mi> <mml:mrow><mml:mo>·</mml:mo> <mml:mo>·</mml:mo></mml:mrow> </mml:msubsup> <mml:annotation>${\mathrm{V}}_{\mathrm{O}}^{ \cdot \cdot }$</mml:annotation></mml:semantics> </mml:math> ) in perovskite-based air electrodes play a crucial role because they can simultaneously facilitate faster reaction kinetics for both ORR and OER. Herein, a simple A-site deficiency engineering is applied to effectively regulate the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msubsup><mml:mi>V</mml:mi> <mml:mi>O</mml:mi> <mml:mrow><mml:mo>·</mml:mo> <mml:mo>·</mml:mo></mml:mrow> </mml:msubsup> <mml:annotation>${\mathrm{V}}_{\mathrm{O}}^{ \cdot \cdot }$</mml:annotation></mml:semantics> </mml:math> concentration of perovskite oxides. The designed La<sub>0.85</sub>Ba<sub>0.1</sub>Co<sub>0.7</sub>Ni<sub>0.3</sub>O<sub>3-</sub> <sub>δ</sub> (L85BCN) demonstrated a high <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msubsup><mml:mi>V</mml:mi> <mml:mi>O</mml:mi> <mml:mrow><mml:mo>·</mml:mo> <mml:mo>·</mml:mo></mml:mrow> </mml:msubsup> <mml:annotation>${\mathrm{V}}_{\mathrm{O}}^{ \cdot \cdot }$</mml:annotation></mml:semantics> </mml:math> concentration and significantly boosted the air electrode reaction by accelerating charge transfer kinetics, which is confirmed by integrated experimental characterizations, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msubsup><mml:mi>V</mml:mi> <mml:mi>O</mml:mi> <mml:mrow><mml:mo>·</mml:mo> <mml:mo>·</mml:mo></mml:mrow> </mml:msubsup> <mml:annotation>${\mathrm{V}}_{\mathrm{O}}^{ \cdot \cdot }$</mml:annotation></mml:semantics> </mml:math> formation energy, and Gibbs free energy variation for ORR and OER processes. Consequently, PCC with L85BCN air electrode yields a remarkable peak power density of 0.76 W cm<sup>-2</sup> and current density of 2.12 A cm<sup>-2</sup> at 1.3 V under 600°C, representing the highest performance among PCCs. This effective A-site deficiency engineering strategy not only discovered a novel, promising air electrode but also advanced PCC development for practical applications. Electrode ; Electrochemistry ; Oxygen evolution ; Ceramic ; Catalysis ; Gibbs free energy ; Limiting current ; Oxygen ; Reversible hydrogen electrode ; Power density Advancements in Solid Oxide Fuel Cells ; Electrocatalysts for Energy Conversion ; Ammonia Synthesis and Nitrogen Reduction