A charge-transfer model considering
the mixed conductivities of proton, oxygen ion, and free electron
in interface-modified La2Ce2O7 (LCO)
electrolyte is designed to analyze the characteristics of proton ceramics
fuel cell in the field of the open-circuit voltage, internal short-circuit
current, proton-transfer number, discharging curves, oxygen/hydrogen
partial pressure, and cell efficiencies. The properties of anode-supported
single cells with the modified anode–electrolyte interface
containing an in situ formed doped BaCeO3 reaction layer
are compared to those of unmodified cells at various temperatures T and H2O partial pressures. Besides, the electrochemical
impedance spectroscopies of both cells were investigated by the relaxation
time distribution to distinguish different polarization processes.
The results indicated that the reaction interface layer can effectively
reduce the internal short-circuit current density and increase the
proton-transfer number of electrolytes. Importantly, the NiO–BaZr0.1Ce0.7Y0.2O3‑δ anode
can also make more protons transfer from anode to cathode and participate
in the cathodic reaction for LCO-based proton ceramics fuel cell.
The polarization of the cell decreases with the increase of water
partial pressure, which leads to the increase of open-circuit voltage
and cell efficiency.