Sr-doped Sm2CuO4 cathode for intermediate temperature solid oxide fuel cells
Abstract The Sm 2 -  x Sr x CuO 4 - d is single-phase with a tetragonal structure across compositional range 0  x 2.8 Sr 0.2 CuO 4 -  d exhibits maximum dc conductivity (6.8(2) S cm − 1 at 640 °C) and minimum activation energy ( E a  = 0.400(6) eV) among studied solid solutions. Minimum polarization resistance ( R p ) value of 1.57(3) Ω cm 2 is obtained at 700 °C for Sm 2.8 Sr 0.2 CuO 4 -  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.