Synthesis and performance of Sr_(1.5)La_xMnO_4 as cathode materials for intermediate temperature solid oxide fuel cell

摘要

A-site non-stoichiometric materials Sr_(1.5)La_xMnO_4 (x = 0.35,0.40,0.45) are prepared via solid state reaction. The structure of these materials is determined to be tetragonal. Both the lattice volume and the thermal expansion coefficient reduce with the decrease of lanthanum content. On the contrary, the conductivity increases and the maximum value of l3.9Scm~(-1) is found for Sr,Sr_(1.5)La_(0.35)MnO_4 at 750 C in air. AC impedance spectroscopy and DC polarization measurements are used to study the electrode performance. The optimum composition of Sr_(1.5)La_(0.35)MnO_4 results in 0.25Ωcm~2 area specific resistance (ASR) at 750 C in air. The oxygen partial pressure measurement indicates that the charge transfer process is the rate-limiting step of the electrode reactions.