A new experimental method to estimate the leakage current in the solid oxide fuel cell with a mixed ionic and electronic conducting electrolyte

The leakage current in a solid oxide fuel cell with a mixed ionic and electronic conducting electrolyte considerably depresses its performance, and current studies mainly focus on the theoretical analysis by numerical models due to the difficulty in the measurement of leakage current. In this paper, a new experimental method to online estimate the leakage current is developed. In this method, the electronic current can be directly measured at theoretical voltage and the electronic conductivity coefficient of the electrolyte can be calculated by this electronic current; the electronic current at the open circuit can be calculated by operating conditions, and the electronic current at any condition can be calculated by the voltage and external current. This experimental method is verified by comparing with other experimental data in the literature and numerical results of a 1D polarization model. The electronic conductivity coefficient of this method shows same order of magnitude to the experimental data. The electronic current at any condition calculated by this method shows good agreement with the model results. The comparison results manifest that this experimental method can be used to online estimate the leakage current and electronic conductivity of the electrolyte.