An ionic conductor Ce_0.8Sm_0.2O_2−Δ (SDC) and semiconductor Sm_0.5Sr_0.5CoO₃ (SSC) composite for high performance electrolyte-free fuel cell

An advanced electrolyte-free fuel cell (EFFC) was developed. In the EFFC, a composite layer made from a mixture of ionic conductor (Ce_0.8Sm_0.2O_2−δ, SDC) and semiconductor (Sm_0.5Sr_0.5CoO₃, SSC) was adopted to replace the electrolyte layer. The crystal structure, morphology and electrical properties of the composite were characterized by X-ray diffraction analysis (XRD), scanning electron microscope (SEM), and electrochemical impedance spectrum (EIS). Various ratios of SDC to SSC in the composite were modulated to achieve balanced ionic and electronic conductivities and good fuel cell performances. Fuel cell with an optimum ratio of 3SDC:2SSC (wt.%) reached the maximum power density of 741 mW cm⁻² at 550 °C. The results have illuminated that the SDC-SCC layer, similar to a conventional cathode, can replace the electrolyte to make the EFFC functions when the ionic and electronic conductivities were balanced.