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Property evaluation of Sm 1‐x Sr x Fe 0.7 Cr 0.3 O 3‐δ perovskites as cathodes for intermediate temperature solid oxide fuel cells
Author(s) -
Xie XiaoBin,
Xiao Jing,
Xu Qing,
Chen Min,
Chen DongChu,
Huang DuanPing,
Zhang Feng
Publication year - 2019
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.4377
Subject(s) - thermal expansion , materials science , cathode , overpotential , oxide , polarization (electrochemistry) , ceramic , exchange current density , perovskite (structure) , electrical resistivity and conductivity , analytical chemistry (journal) , electrochemistry , electrode , crystallography , metallurgy , chemistry , electrical engineering , chromatography , engineering , tafel equation
Summary Perovskite‐type (ABO 3 ) complex oxides of Sm 1‐x Sr x Fe 0.7 Cr 0.3 O 3‐δ (x = 0.5‐0.7) series were prepared by a glycine‐nitrate combustion process. The crystal structure, oxygen nonstoichiometry, electrical conducting, thermal expansion, and electrocatalytic properties of Sm 1‐x Sr x Fe 0.7 Cr 0.3 O 3‐δ perovskites were inspected in view of their use as cathode materials for intermediate temperature solid oxide fuel cells (IT‐SOFCs). Changing the content of Sm 3+ at the A‐site was demonstrated to be effective in tuning the structure and properties. The variation of the various properties with Sm 3+ content was explained in relation to the corresponding evolution of the crystal structure and oxygen nonstoichiometry. Sm 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3‐δ (x = 0.7) was determined to be the optimal composition in the Sm 1‐x Sr x Fe 0.7 Cr 0.3 O 3‐δ series based on a trade‐off between the thermal expansion and electrocatalytic properties. Sm 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3‐δ ceramic specimen exhibited an electrical conductivity of approximately 40 S·cm −1 at 800°C and a thermal expansion coefficient of 14.1 × 10 −6 K −1 averaged in the temperature range from 40°C to 1000°C. At 800°C in air, Sm 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3‐δ electrode showed a cathodic polarization resistance of 0.19 Ω·cm 2 , a cathodic overpotential of 30 mV at current density of 200 mA·cm −2 , and an exchange current density of 257 mA·cm −2 . It is suggested that Sm 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3‐δ is a potential candidate material for cathode of IT‐SOFCs in light of its overall properties.