New ionic diffusion strategy to fabricate proton-conducting solid oxide fuel cells based on a stable La2Ce2O7 electrolyte

A composite of NiO-BaZr0.1Ce0.7Y0.2O3−δ (NiO-BZCY) was successfully prepared by a simple one-step-combustion process and applied as an anode for solid oxide fuel cells based on stable La2Ce2O7 (LCO) electrolyte. A high open circuit voltage of 1.00 V and a maximum power density of 315 mW cm−2 were obtained with NiO-BZCY anode and LCO electrolyte when measured at 700 °C using humidified hydrogen fuel. SEM-EDX and Raman results suggested that a thin BaCeO3-based reaction layer about 5 μm in thickness was formed at the anode/electrolyte interface for Ba cations partially migrated from anode into the electrolyte film. Impedance spectra analysis showed that the activation energy for LCO conductivity differed with the anode materials, about 52.51 kJ mol−1 with NiO-BZCY anode and 95.08 kJ mol−1 with NiO-LCO anode. The great difference in these activation energies might suggest that the formed BaCeO3 reaction layer could promote the proton transferring numbers of LCO electrolyte.