Sr-doped Sm2CuO4 cathode for intermediate temperature solid oxide fuel cells

The Sm2 - xSrxCuO4 - d is single-phase with a tetragonal structure across compositional range 0 < x < 0.5. Sm2.8Sr0.2CuO4 - d exhibits maximum dc conductivity (6.8(2) S cm− 1 at 640 °C) and minimum activation energy (Ea = 0.400(6) eV) among studied solid solutions. Minimum polarization resistance (Rp) value of 1.57(3) Ω cm2 is obtained at 700 °C for Sm2.8Sr0.2CuO4 - d. Low-frequency impedance spectra are modeled using Gerischer element. Magnitude of Gerischer impedance decreases significantly with increase in Sr content. Oxygen partial pressure-dependent polarization study suggests that non-charge transfer oxygen-adsorption desorption and diffusion are important steps during overall oxygen reduction reaction processes.