Microstructure-scaled active sites imaging of a solid oxide fuel cell composite cathode

Distribution of Reaction Sites in SOFC Cathode through Oxygen Isotope Labeling with Three-Dimensional Microstructural Analysis

“…The fabrication process is given in our previous work. 14 On the cathode, an LSM layer was attached as a current collector. The thickness of the electrolyte, anode, cathode, and current collector was 300 μm, 23 μm, 28 μm, and 20 μm, respectively.…”

“…In light of the above issues, the authors have recently developed an imaging technique of active sites in porous electrodes through oxygen isotope labeling and subsequent quenching process using a water-cooled helium gas impinging jet. [14][15][16] In these prior studies, active sites of LSM/scandia-stabilized zirconia (ScSZ) 14 or LSM/YSZ 15 cathodes were visualized in a microstructure scale with a help of tens of nanometer-resolution secondary ion mass spectroscopy (SIMS) based on the 18 O labeling. From the observed nonuniform 18 O distribution, it was represented that the active sites were highly distributed, while the dominant factor of the non-uniformity was not clearly revealed.…”

Direct Visualization of Oxygen Incorporation for Oxygen Reduction on Porous Mixed-Conducting LaSrCoO3 Cathode

“…Details of the helium gas impinging jet supplied through the water-cooled nozzles for quenching the reaction in SOFC operated at high temperature has previously been described elsewhere. 28 The 16 O/ 18 O exchange under open circuit voltage (OCV) condition was also carried out in the same manner described above; however, no current was applied during the isotopic exchange. An…”

“…A technique of oxygen-18 isotope ( 18 O) labelling combining with an imaging capability of a secondary ion mass spectrometer (SIMS) has been demonstrated in numerous studies to be an appealing method for experimental investigation of active reaction sites for oxygen reduction at cathodes of SOFCs. [20][21][22][23][24][25][26][27][28] A recent study by Nagasawa and Hanamura showed that electrochemically active sites in porous composite of strontium-doped lanthanum manganite (LSM)/scandia stabilized zirconia (ScSZ) cathode can be visualized in microstructure scale by applying an isotopic oxygen ( 16 O/ 18 O) exchange experiment under applied constant current density with an immediately subsequent rapid-cooling of cell temperature. 28 Their results of 18 O images provided the first experimental evidence of active reaction sites of SOFC composite cathode in an electrode-particle scale.…”

“…[20][21][22][23][24][25][26][27][28] A recent study by Nagasawa and Hanamura showed that electrochemically active sites in porous composite of strontium-doped lanthanum manganite (LSM)/scandia stabilized zirconia (ScSZ) cathode can be visualized in microstructure scale by applying an isotopic oxygen ( 16 O/ 18 O) exchange experiment under applied constant current density with an immediately subsequent rapid-cooling of cell temperature. 28 Their results of 18 O images provided the first experimental evidence of active reaction sites of SOFC composite cathode in an electrode-particle scale. Other recent studies by Horita et al and Nishi et al demonstrated how 18 O tracer experiments under applied electrical fields with subsequent SIMS detection of the incorporated 18 O are very useful for investigating current-driven oxygen diffusion from cathode to anode in practical SOFC stacks 20,21 and single button cells.…”