Boosting intermediate temperature performance of solid oxide fuel cells via a tri‐layer ceria–zirconia–ceria electrolyte

Using cost-effective fabrication methods to manufacture a high-performance solid oxide fuel cell (SOFC) is helpful to enhance the commercial viability. Here, we report an anode-supported SOFC with a three-layer Gd$_{0.1}$Ce$_{0.9}$O$_{1.95}$ (gadolinia-doped-ceria [GDC])/Y$_{0.148}$Zr$_{0.852}$O$_{1.926}$ (8YSZ)/GDC electrolyte system. The first dense GDC electrolyte is fabricated by co-sintering a thin, screen-printed GDC layer with the anode support (NiO–8YSZ substrate and NiO–GDC anode) at 1400°C for 5 h. Subsequently, two electrolyte layers are deposited via physical vapor deposition. The total electrolyte thickness is less than 5 μm in an area of 5 × 5 cm$^2$, enabling an area-specific ohmic resistance as low as 0.125 Ω cm$^{−2}$ at 500°C (under open circuit voltage), and contributing to a power density as high as 1.2 W cm$^{−2}$ at 650°C (at an operating cell voltage of 0.7 V, using humidified [10 vol.% H$_2$O] H$_2$ as fuel and air as oxidant). This work provides an effective strategy and shows the great potential of using GDC as an electrolyte for high-performance SOFC at intermediate temperature.