BaCo0.4Fe0.4Nb0.1Sc0.1O3-delta perovskite oxide with super hydration capacity for a high-activity proton ceramic electrolytic cell oxygen electrode

Proton ceramic electrolytic cells (PCECs) are regarded as superior candidates for largescale hydrogen production by water electrolytic because they are efficient and weakly temperature-dependent. However, the intrinsically poor water-storage capability (hydration) and slow proton mobility of traditional PCEC oxygen electrodes retards the activity of electrochemical water decomposition to oxygen. The sluggish decomposition process has pre-vented the extensive application of PCECs. Herein, we report a Nb5+ and Sc3+ co-doped BaCo0.4-Fe0.4Nb0.1Sc0.1O3-delta (BCFNS) perovskite oxygen electrode that exhibits remarkably low polarization resistances (e. g., 0.079 Omega(.)cm(2) at 650 degrees C) in air humidified with 3 vol% H2O. Both experiments and computational calculations linked this high performance to the synergistic effect of Nb5+ and Sc3+ in tuning the oxygen-vacancy concen-tration and the hydration reaction between oxygen vacancies and water molecules. This unique synergistic mechanism endows BCFNS with strong hydration capacity, boosting the formation of protonic defects and reducing the proton-migration barrier. Benefiting from these features, a single PCEC with a BCFNS oxygen electrode achieved much higher current densities than newly reported PCECs: 1224.91, 914.05, 622.18, and 314.89 mAcm(-2) at 1.3 V and 650 degrees C, 600 degrees C, 550 degrees C, and 500 degrees C, respectively. Such excellent electrolytic performance suggests that Nb5+ and Sc3+ co-doping can promote the hydration capability and proton mobility of electrode materials for high-performance PCECs.

Automated summary

This article reports on the development of a Nb5+ and Sc3+ co-doped BaCo0.4-Fe0.4Nb0.1Sc0.1O3-delta (BCFNS) perovskite oxygen electrode, which exhibits strong hydration capability and proton mobility. The co-doping of Nb5+ and Sc3+ significantly improves the electrolytic performance of PCECs, leading to higher current densities.