Enhanced Electrochemical Performance of a Ba0.5Sr0.5Co0.7Fe0.2Ni0.1O3-δ-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ Composite Oxygen Electrode for Protonic Ceramic Electrochemical Cells

The performance of protonic ceramic electrochemical cells (PCECs) is largely restricted by the slow oxygen reactions on the oxygen electrode. Herein, an active composite oxygen electrode Ba0.5Sr0.5Co0.7Fe0.2Ni0.1O3-delta-BaZr0.1Ce0.7Y0.1Yb0.1O3-delta (BSCFN-BZCYYb) with various mass ratios (6:4, 7:3, 8:2, and 9:1) is electrochemically investigated on fuel electrode-supported PCECs. BSCFN powder, with rich oxygen vacancies, shows a good chemical compatibility with BZCYYb electrolyte, as confirmed by the analyses of thermal gravimetric analysis and X-ray diffraction patterns. It is indicated that composite electrode with a ratio of 8:2 shows the best performance. For example, a peak power density (P-max) of 1.14 W cm(-2), an electrode polarization resistance (R-p) of 0.062 Omega cm(2), and a reasonable durability test of 24 h at -0.5A cm(-2) are delivered at 750 degrees C for the fuel cells with BSCFN-BZCYYb electrode with the ratio of 8:2. In addition, a stable operation (similar to 50 h) of cell with BSCFN-BZCYYb electrode (8:2 mass ratio) in dual modes of electrolysis and fuel cell (2 h for each mode) at +/- 0.5 A cm(-2) is obtained, demonstrating a good reversibility.

Automated summary

The study found that the composite electrode with an 8:2 mass ratio of BSCFN-BZCYYb exhibits the best performance in fuel cells, with a peak power density of 1.14 W/cm2, an electrode polarization resistance of 0.062 ohm·cm2, and a reasonable durability test lasting 24 hours at -0.5A/cm2 at 750 degrees Celsius. Additionally, a stable operation of the cell in dual modes of electrolysis and fuel cell for approximately 50 hours at +/- 0.5 A/cm2 was achieved, demonstrating good reversibility.