The heterogeneous electrolyte of CuFeO2 nano-flakes composited with flower-shaped ZnO for advanced solid oxide fuel cells

The flower-shaped ZnO was synthesized to form composite with the delafossite structure CuFeO2. The composite heterojunction formed for the ZnO-CuFeO2 composite material demonstrates a profound significance for exploring novel materials in solid oxide fuel cell (SOFC) field. At 550 °C, power outputs of 300 mW cm−2 and 468 mW cm−2 were achieved for SOFC devices using pure ZnO and composite with CuFeO2 as the electrolytes, respectively. The composite showed a good performance at low temperatures, for instance, it showed a power output of 148 mW cm−2 at 430 °C. The studies on photocurrent-time curves with visible light on/off irradiation provided an evidence for electron-hole separation. The heterojunctions separate holes and electrons, preventing short-circuiting while used in the SOFC device. These results demonstrate that introducing the heterojunctions in the electrolyte is an innovative approach for advanced SOFCs.