Three‐dimensional Quantitative Evaluation of Interfacial Mass Transfer for Performance Enhanced and Durable Large‐scale Reversible Protonic Ceramic Cells

Reversible protonic ceramic cells (R-PCCs) hold significant promise for energy storage and conversion. However, achieving high-performance, large-scale cells remains challenging, primarily due to issues with compatibility and adhesion at the electrode-electrolyte interface. Here, a scalable strategy is presented for regulating an active interface structure (AIS) via tape casting to develop high-performance, durable R-PCCs. The AIS, located between BaZr₀.₁Ce₀.₇Y₀.₁Yb₀.₁O₃-δ (BZCYYb) electrolyte and Ni-BZCYYb anode, is systematically analyzed for its impact on electrochemical performance. Cells with a 20 µm AIS (20AIS) achieve peak power densities of 1.50 W cm⁻² and current densities of - 1.66 A cm^- ² at 650 °C, outperforming conventional cells without AIS (0AIS) by ≈50%. The stable reversible operation is maintained for over 200 h. FIB-SEM and 3D reconstruction reveal that the 20AIS sample exhibits a 65.7% increase in triple-phase boundary length, despite reduced pore counts affecting gas transport, optimizing the balance between TPB length and transport resistance. Furthermore, the scalability of this approach is demonstrated by fabricating 10 × 10 cm² cells, meeting industry standards and reinforcing the method's commercial viability. These findings highlight a practical pathway for advancing R-PCC technology toward industrial applications.