A high-performance oxygen electrode for solid oxide cells: Compositional optimisation of barium cobaltite-based composites.

• Effect of composition on the polarisation resistance of BCO/CGO electrodes. • 50 vol% CGO-50 vol% BCO shows the lowest polarisation resistance. • The improvement relies on an increased triple-phase boundary (TPB) length. [Display omitted] Solid oxide electrochemical cells are promising devices for energy conversion and chemical synthesis. In this respect, one of the main challenges to improving cell performance is the decrease in the polarisation resistance (R p) of the oxygen electrodes. Here, the electrochemical properties of composite electrodes of Ba 2 Co 9 O 14 /Ce 0.8 Gd 0.2 O 2- δ (BCO/CGO) are investigated by electrochemical impedance spectroscopy at 600–800 °C. The composite with 50 vol% CGO exhibits the lowest polarisation resistance, 0.3 Ω cm² at 600 °C in O 2. The comparatively superior performance results from an increased triple-phase boundary (TPB) length due to the increased percolation of both phases. This successful result presents a high-performing oxygen electrode for solid oxide electrochemical systems. [ABSTRACT FROM AUTHOR]