Processing SCNT(SrCo_0.8Nb_0.1Ta_0.1O_3-δ)-SCDC(Ce_0.8Sm_0.05Ca_0.15O_2-δ) composite into semiconductor-ionic membrane fuel cell (SIMFC) to operate below 500 °C

High power density performance at intermediate (600 °C–450 °C) temperatures (IT) must be considered in the development of solid oxide fuel cell (SOFC). A niobium and tantalum co-doped perovskite material SCNT (SrCo_0.8Nb_0.1Ta_0.1O_3-δ) can be used as a cathode for IT-SOFC due to its (H⁺/O²⁻/e⁻) triple conduction and promising catalysis activity. In this work, the SCNT was composited with ionic conductor SCDC(Ce_0.8Sm_0.05Ca_0.15O_2-δ) and processed as electrolyte membrane into semiconductor-ionic membrane fuel cell (SIMFC), which delivered an appreciable performance at IT, i.e., a peak power output of 1016 mW/cm² at 550 °C and 401 mW/cm² at 450 °C, respectively. The high performance mainly originated from the (H⁺/O²⁻) dual-ion conduction of SCNT as well as the high oxygen ion conductivity of SCDC, the SCNT-SCDC electrolyte layer adjacent to cathode have promoted the oxygen reduction reaction (ORR) with some extent because of the excellent catalysis activity of SCNT. Moreover, the on-line generated carbonate suppressed the electronic conductivity and resulted in the attractive density of SCNT-SCDC electrolyte to further contribute to the desired cell performance.