Self-Recoverable Symmetric Protonic Ceramic Fuel Cell with Smart Reversible Exsolution/Dissolution Electrode

Abstract

This study unveils a novel concept of symmetric protonic ceramic fuel cells (symm-PCFCs) with the introduction of a self-recoverable electrode design, employing the innovative material BaCo_0.4Fe_0.4Zr_0.1Y_0.1O_3-δ (BCFZY). This research marks a significant milestone as it demonstrates the bi-functional electrocatalytic activity of BCFZY for the first time. Utilizing density functional theory simulations, the molecular orbital interactions and defect chemistry of BCFZY are explored, uncovering its unique capability for the reversible exsolution and dissolution of Co-Fe nanoparticles under redox conditions. This feature is pivotal in promoting both hydrogen oxidation and oxygen reduction reactions. Leveraging this insight, a cell is fabricated exhibiting high electrocatalytic activity and fuel flexibility as evidenced by the peak power densities of ≈350, 287, and 221 mW cm⁻² (at 600 °C) with hydrogen, methanol, and methane as fuels, respectively. Experiments also show that the reversible exsolution/dissolution mitigates performance degradation, enabling prolonged operational life through self-recovery. This approach paves the way for novel, advanced, durable, and commercially viable symm-PCFCs.