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Title: Electrochemically influenced cation inter-diffusion and Co 3O 4 formation on La 0.6Sr 0.4CoO 3 infiltrated into SOFC cathodes

Nanosized LSC electrocatalyst was infiltrated into a porous scaffold cathode composed of Sm 2O 3-doped CeO 2 (SDC) and La 0.6Sr 0.4Co 0.2Fe 0.8O 3-δ (LSCF) in a commercial button solid oxide fuel cell (SOFC). To understand the stability of cathodes infiltrated with LSC, the infiltrated composite cells were subjected to both electrochemical operating and thermal aging states at 750 °C for 1500 h. Nanostructure and local chemistry evolution of La 0.6Sr 0.4CoO 3 (LSC) infiltrated cathodes upon operation and aging were investigated by transmission electron microscopy. After operation, the LSC remained a cubic perovskite, and the crystal grains exhibit comparable size to as-infiltrated LSC grains. Inter-diffusion of Fe from the LSCF to a Fe-incorporated LSC layer developed on the LSCF backbone. However, only sharp interfaces were observed between LSC and SDC backbone in the as-infiltrated cathode and such interfaces remain after operation. The infiltrated LSC on the SDC backbone also retains granular particle morphology. Furthermore, newly grown Co 3O 4 nanocrystals were found in the operated cathode. After thermal aging, on the other hand, cation inter-diffusion across the interfaces of the infiltrate particles and the cathode backbones is less than that from the operated cells. Lastly, the following hypothesismore » is proposed: Co 3O 4 forms on LSC arising from local charge balancing between cobalt and oxygen vacancies.« less
 [1] ;  [2] ;  [1] ;  [3]
  1. National Energy Technology Lab. (NETL), Albany, OR (United States); West Virginia Univ., Morgantown, WV (United States)
  2. National Energy Technology Lab. (NETL), Albany, OR (United States)
  3. West Virginia Univ., Morgantown, WV (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0167-2738; PII: S0167273815002337
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Solid State Ionics
Additional Journal Information:
Journal Volume: 278; Journal Issue: C; Journal ID: ISSN 0167-2738
Research Org:
National Energy Technology Lab. (NETL), Albany, OR (United States)
Sponsoring Org:
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 30 DIRECT ENERGY CONVERSION; solid oxide fuel cells; cathode infiltration; interface; cation inter-diffusion; transmission electron microscopy