Scalable Fabrication and Resistance Deconvolution of Ni/BCZY Fuel Electrode-Supported Protonic Ceramic Cells

Protonic ceramic cells (PCCs) are emerging as promising technologies for energy conversion at intermediate temperatures (400-700 °C). Here, we present a comprehensive study on the scalable fabrication and resistance deconvolution of Ni/BaCe_0.7Zr_0.1Y_0.2O_3-δ (BCZY) fuel electrode-supported PCCs featuring triple-conducting PrNi_0.5Co_0.5O_3-δ (PNC) oxygen electrodes. The Ni/BCZY|BCZY half cells are fabricated using commercially relevant tape-casting methods in dimensions of 18 x 18 cm² before sintering. The sintering process of both the half cells and the PNC oxygen electrodes is optimized by examining the influence of sintering temperature on cell microstructure. Even a deviation of 50 °C in the sintering temperature of the PNC electrode can result in a remarkable 5-fold difference in cell performance. Through comprehensive analysis of electrochemical impedance spectroscopy data obtained under various gas supply and operating temperature conditions, different electrode processes are successfully identified, and their respective contributions to the overall resistance of the cell are quantified. The results reveal that the resistance associated with the PNC oxygen electrode processes primarily governs the total polarization resistance (R_p), while the resistance associated with the Ni/BCZY fuel electrode is considerably smaller. During short-term durability tests, the cell undergoes continuous activation. The changes in resistance associated with different electrode processes indicate that the major activation of the cell is contributed by the PNC oxygen electrode. After durability tests, the resistance associated with reactions occurring on the Ni/BCZY fuel electrode contributes the highest percentage to the total R_p. Postmortem analysis is performed on the cell after the durability tests. Our work provides insights to guide the design and optimization of PCCs.