Investigation of cobalt-free cathode material Sm_(0.5)Sr_(0.5)Fe_(0.8)Cu_(0.2)O_(3-δ) for intermediate temperature solid oxide fuel cell

摘要

A cobalt-free cubic perovskite oxide Sm_(0.5)Sr_(0.5)Fe_(0.8)Cu_(0.2)O_(3-δ) (SSFCu) was investigated as a novel cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The thermal expansion coefficient (TEC) of SSFCu was close to that of Sm_(0.2)Ce_(0.8)O_(1.9)(SDC) electrolyte and the electrical conductivity of SSFCu sample reached 72-82 S cm"1 in the commonly operated temperatures of IT-SOFCs (400-600 ℃). Symmetrical electrochemical cell with the configuration of SSFCu/SDC/SSFCu was applied for the impedance study and area specific resistance (ASR) of SSFCu cathode material was as low as 0.085 Ω cm~2 at 700 ℃. Laboratory-sized tri-layer cells of NiO-SDC/SDC/SSFCu were operated from 450 to 700 ℃ with humidified hydrogen (～3% H_2O) as fuel and the static air as oxidant. A maximum power density of 808 mW cm~2 was obtained at 700 ℃ for the single cell.