In this work, we have employed an evolutionary programming technique to analyse the impedance spectroscopy (IS) of a ceramic proton conductor BaCe 0.35 Zr 0.5 Y 0.15 O 3-δ (BCZY) to study its proton transport properties as well as the electrode reactions kinetics at the Pt|BCZY interface. The distribution functions of relaxation times (DFRT) obtained from the impedance analysis were used to evaluate the physical parameters such as relaxation time constant, resistance, reactance/capacitance, conductivities, activation energies, grain-boundary space charge potential Φ(0, T), and electrode polarization resistance. The effect of ZnO sintering aid (2 wt%) on charge-transfer processes at bulk, grain boundaries and Pt| BCZY interface were thoroughly studied. Φ(0, T) is increased and grain-boundary conductivity (σ gb ) is decreased by an order of magnitude due to the presence of Zn at the grain boundaries, whereas bulk properties appear to be unchanged. Variation in σ gb with temperature is explained by correlating the grain-boundary capacitance (C gb ), relaxation time (τ gb ), space charge effect, and the defect associations (eg, Y-OH). The anodic functions, for example, hydrogen oxidation kinetics at the electrode (Pt) surface and Pt-BCZY interface, are explained through the symmetrical cell study and the behavior of relaxation time constants (τ) with temperature.
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