Cu doping enhanced the performance of BaFe0.8Zr0.1Y0.1O3-δ cathode for a proton-conducting solid oxide fuel cell at low temperature

BaFe 0.8-x Cu x Zr 0.1 Y 0.1 O 3-δ (0 ≤ x ≤ 0.15) perovskite was investigated as the cathode material for low-temperature proton-conducting solid oxide fuel cells (H-SOFCs). Cu doping in BaFe 0.8 Zr 0.1 Y 0.1 O 3-δ (Cu0) improves the proton conductivity and surface exchange kinetics. The chemical bulk diffusion coefficient ( D chem ) and the chemical oxygen surface exchange coefficient ( K chem ) of BaFe 0.75 Cu 0.05 Y 0.1 Zr 0.1 O 3-δ (Cu5) and BaFe 0.7 Cu 0.1 Y 0.1 Zr 0.1 O 3-δ (Cu10) were both increased compared to Cu0. Thermogravimetric analysis (TGA) of Cu5 and Cu10 in air showed larger revsivle oxygen loss than that of Cu0. A significant improvement in current output was observed at 600 °C: cell with BaFe 0.65 Cu 0.15 Y 0.1 Zr 0.1 O 3-δ (Cu15), Cu10 and Cu5 cathode demonstrated current densities 100.7 %, 438.4 %, and 253.8 % higher, respectively, than the one with Cu0 at 0.6 V after more than 100 h of durability. This work demonstrated that the optimal Cu doping on ferrite cathode could improve the proton transport kinetics and is able to deliver a improved performance and stability for low-temperature (≤600 °C) H-SOFCs.