Low-temperature co-sintering of co-ionic conducting solid oxide fuel cells based on Ce_0.8Sm_0.2O_1.9-BaCe_0.8Sm_0.2O_2.9 composite electrolyte

A composite electrolyte Ce_0.8Sm_0.2O_1.9-BaCe_0.8Sm_0.2O_2.9 (SDC-BCS) material for co-ionic conducting solid oxide fuel cells was prepared by microwave-assisted sol-gel technique. The crystallization, morphology, and sintering characteristics were investigated by X-ray diffraction and scanning electron microscopy. The obtained SDC-BCS composite electrolyte powders distribute uniformly, and SDC and BCS crystalline grains play a role as matrix for each other in the composite electrolyte. Anode-supported solid oxide fuel cells of NiO-Ce_0.8Sm_0.2O_1.9/Ce_0.8Sm_0.2O_1.9-BaCe_0.8Sm_0.2O_2.9/Ce_0.8Sm_0.2O_1.9-SrCo_0.9Ti_0.1O_2.55 (NiO-SDC/SDC-BCS/SDC-SCT) were fabricated based on the nanocomposite electrolyte powders. The electrochemical performances were tested at 500–650 °C using humidified hydrogen as fuel. Results demonstrated that the anode-supported half cells could be sintered at 1,300 °C with a dense electrolyte layer and a porous anode structure. Moreover, the single cell with 40-μm-thick electrolyte layer achieved an open-circuit voltage (OCV) of 0.77 V and a maximum power density of 621 mW cm⁻² at 650 °C.