Structural and electrochemical properties of B-site Mg-doped La0.7Sr0.3MnO3−δ perovskite cathodes for intermediate temperature solid oxide fuel cells

• Conventional cathode material La0.7Sr0.3MnO3 is modified by B-site Mg doping.
• The effects of Mg doping are explored on structure and electrochemical properties.
• LSMM20 has the potential as a cathode candidate material for IT-SOFCs.

A series of La0.7Sr0.3Mn3−δ (LSM)-based perovskite cathode material with B-site Mg-doped composition La0.7Sr0.3Mn1−xMgxO3−δ (LSMM, x = 0, 0.1, 0.2) was successfully synthesized by a combined EDTA-citrate complexing method. The effect of the introduction of Mg into the Mn-site of La0.7Sr0.3MnO3 on the structural characteristics and electrochemical properties of the samples was specifically investigated. Among all the samples, La0.7Sr0.3Mn0.8Mg0.2O3−δ (LSMM20) showed larger BET surface areas (8.72 m2/g), a lower thermal expansion coefficient of ∼10.6 × 10−6 K−1 in a temperature range of 50–900 °C and a higher oxygen vacancy concentration. The good electrochemical performance of LSMM20 was manifested from its lower polarization resistance (Rp), resulting in a maximum power density of 187 mW cm−2 for an electrolyte supported single cell at 800 °C. This study indicates the potential of LSMM20 as a cathode candidate material for IT-SOFCs.

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