Novel three-phase-coexisting anode boosts green hydrogen production in protonic solid oxide electrolysis cells

To overcome this challenge, a research team led by scientists from Chaozhou Three-Circle (Group) Co., Ltd., Guangzhou University, and the Guangdong Academy of Sciences has engineered a novel three-phase-coexisting La₀.₉Ba₀.₁Co₀.₇Ni₀.₂Ag₀.₁O₃₋δ (LBCNA) anode. By combining a main rhombohedral ABO₃-type perovskite, a Ruddlesden-Popper (RP) phase, and surface-anchored metallic silver (Ag) nanoparticles, the team achieved unprecedented electrochemical activity and stability for high-temperature water splitting. The research findings have been published in ENGINEERING Energy (2026, 20(4): 10887).

Unlocking Synergy Across Bulk and Surface

The researchers discovered that incorporating highly electronegative Ag⁺ ions into the parent perovskite matrix intentionally weakens the metal–oxygen bonds, triggering the exsolution/leaching of cobalt and nickel ions. This self-driven phase transformation forms an RP-type layer alongside metallic Ag nanoparticles (~10 nm in size) uniformly anchored on the oxide surface.

This three-phase architecture works in synergy to address all major limitations of traditional P-SOEC anodes:

• RP-Type LBCNA Phase: Expands the proton conduction pathways within the bulk material, achieving a high hydrated proton concentration of 0.051 mol·unit⁻¹ at 600 °C.
• Co–Ni Inter-Cation Charge Transfer: Elevates Co to a higher oxidation state (Co³⁺ proportion reaches 59.6%), which drastically reduces the reaction energy barrier for water splitting intermediates.
• Metallic Ag Nanoparticles: Boost electronic conductivity and lower the oxygen-exchange energy barrier on the catalyst surface.
• Abundant Oxygen Vacancies: The optimized LBCNA-900 sample exhibits an elevated ratio of adsorbed-to-lattice oxygen (35.38%), facilitating rapid oxygen-ion transport.

Key Highlights and Findings

• Ultra-Low Interfacial Resistance: The optimized LBCNA-900 anode (calcined at 900 °C) achieved an ultra-low area-specific resistance (ASR) of 0.10 Ω·cm² at 600 °C in a BZCYYb4411-based symmetric cell, significantly outperforming conventional and recently reported advanced anodes.
• Exceptional Electrolysis Performance: When integrated into a single-button P-SOEC, the cell delivered a high current density of 1.8 A·cm⁻² at 1.3 V and 600 °C (and 3.3 A·cm⁻² at 700 °C).
• Outstanding Operational Durability: The P-SOEC with the LBCNA-900 anode demonstrated stable continuous operation for 100 hours at 600 °C under a constant current density of 0.5 A·cm⁻² without noticeable degradation.
• Universal Design Paradigm: The multi-phase exsolution strategy opens a versatile pathway for designing multi-functional electrocatalysts across various energy storage and conversion devices.

"By rationally constructing a three-phase-coexisting structure, we successfully addressed both charge transport limitations and sluggish catalytic surface kinetics simultaneously," explained the co-corresponding authors. "This work provides a clear and scalable design strategy for next-generation, high-performance P-SOEC anodes."

About the Research

Journal: ENGINEERING Energy

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Cite this article: Zheng, F., Song, C., Wang, Y., Yuan, B., Tang, C., Chen, L., Liu, T., Mao, J., Wang, N., & Ye, S. (2026). Three-phase-coexisting anode enabling high-performance water splitting in protonic solid oxide electrolysis cells. ENGINEERING Energy, 20(4), 10887. https://doi.org/10.1007/s11708-026-1088-7