Exchange current model for (La0.8Sr0.2)0.95MnO3 (LSM) porous cathode for solid oxide fuel cells

JOURNAL OF POWER SOURCES

卷:315

Article

Miyoshi, Kota¹  Miyamae, Takuma¹  Iwai, Hiroshi¹  Saito, Motohiro¹  Kishimoto, Masashi¹  Yoshida, Hideo¹ 

[1] Kyoto Univ, Dept Aeronaut & Astronaut, Kyoto 6158540, Japan

关键词: Solid oxide fuel cells;    LSM;    Cathode;    FIB-SEM;    Exchange current;   

DOI  :  10.1016/j.jpowsour.2016.02.076

来源: Elsevier

【 摘 要 】

In this paper, we propose an empirical formula for i(0,TPB), the exchange current density per unit triple phase boundary (TPB) length, for porous lanthanum strontium manganite (LSM) cathodes of solid oxide fuel cells (SOFCs); the evaluation of i(0,TPB) is of crucial importance in numerical simulations of electrodes based on reconstructed microstructures obtained by a dual beam focused ion beam scanning electron microscopy (FIB-SEM) and tomography techniques. To derive a widely applicable empirical formula for i(0,TPB), electrochemical measurements of porous LSM cathodes are conducted under various oxygen partial pressures (0.05-0.25 atm) and temperatures (800-950 degrees C). By comparing the derived formula with that derived from a thin and dense patterned LSM electrode used in previous studies, it is found that at an air temperature of 800 degrees C, imTs derived from a porous LSM cathode is approximately 40% smaller than that for the patterned electrode. This can be attributed to the fact that the electrochemical reaction in thin and dense electrodes can occur not only at the TPBs but also at the LSM surface owing to the non-negligible ionic conductivity of LSM. The derived formula is also applied to a three-dimensional numerical simulation to confirm its validity. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free