Oxygen Electrode PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ–BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ with Different Composite Proportions for Proton-Conducting Solid Oxide Electrolysis Cells

Proton-conducting solid oxide electrolysis cell (H-SOEC), as a hydrogen production device using proton conductor oxides as an electrolyte, has gained attention due to its various advantages of being more suitable for operating conditions at intermediate and low temperatures. However, its commercialization urgently needs to address the issue of insufficient catalytic activity of the oxygen electrode at lower temperatures. In this work, PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ –BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3−δ (PBSCF-BZCYYb) series composite materials (denoted as PBSCF-BZCYYb46, PBSCF- BZCYYb55, and PBSCF-BZCYYb64 based on the mass ratios of PBSCF and BZCYYb as 4:6, 5:5, and 6:4, respectively) are prepared and applied as oxygen electrodes for H-SOECs. The H-SOECs with the structure of PBSCF-BZCYYb|BZCYYb|NiO-BZCYYb (active layer)|NiO-BZCYYb (support layer) are prepared and recorded as Cell 1, Cell 2, and Cell 3 with PBSCF-BZCYYb46, PBSCF-BZCYYb55, and PBSCF-BZCYYb64 as oxygen electrodes. The H-SOECs exhibit electrolysis current densities of 669.00, 743.80, and 503.30 mA cm –2 under 1.3 V at 650 °C, respectively. The cells also show considerable stability in the constant voltage electrolysis of 179.5, 152.8, and 83.0 h, respectively. Through the comparison of various electrochemical properties, PBSCF-BZCYYb55 is considered the most promising oxygen electrode material in this work.