Growth of Gd0.3Ca2.7Co3.82Cu0.18O9-δ-BaCe0.6Zr0.2Y0.2O3-δ bulk heterojunction cathode interlayer by pulsed laser deposition for enhancing protonic solid oxide fuel cell performance

The triple-conducting (e−/H+/O2−) oxides have been extensively studied as the most promising cathode materials for protonic solid oxide fuel cells (P-SOFCs) because of their excellent catalytic activity at lower operating temperatures of <600 °C. However, direct application of these cathode materials by brush-painting or screen-printing provides limited contact area with the underlying electrolyte layer, resulting in high cathode ohmic and polarization resistances. In this study, it is demonstrated that a bulk heterojunction Gd0.3Ca2.7Co3.82Cu0.18O9-δ (GCCCO)-BaCe0.6Zr0.2Y0.2O3-δ (BCZY) layer with a domain width of ∼5 nm can be grown by pulsed laser deposition (PLD) via spontaneous phase separation. Such a nanocomposite interlayer between spin-coated BCZY electrolyte and brush-painted GCCCO cathode can effectively increases the interfacial area between the two distinct phases and facilitates proton transport across the interface. This electrode design reduces the ohmic resistance by 0.35 Ω cm2 and the polarization resistance by a factor of three, thus significantly boosting the cell performance.