TY - JOUR
T1 - Investigation of rate-determining step of LaNi0.6Co0.4O3-δ film electrode
AU - Budiman, R. A.
AU - Uzumaki, Y.
AU - Hashimoto, Shinichi
AU - Nakamura, T.
AU - Yashiro, K.
AU - Bagarinao, K. D.
AU - Kishimoto, H.
AU - Yamaji, K.
AU - Horita, T.
AU - Amezawa, K.
AU - Kawada, T.
N1 - Funding Information:
Funding information This work was supported by JST, Japan, as part of the BPhase Interface Science for Highly Efficient Energy Utilization^ project in strategic basic research program, CREST.
Publisher Copyright:
© 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2018/7/1
Y1 - 2018/7/1
N2 - The rate-determining step (RDS) in the oxygen reduction process on a LaNi0.6Co0.4O3-δ film electrode was analyzed using electrochemical impedance spectroscopy in varied temperatures (873–1073 K), oxygen partial pressures (1–10−3 bar), and DC bias. From the evaluation of the area-specific interfacial conductivity, σE, and chemical capacitance, CE, it is suggested that the RDS is surface reaction under low p(O2) (10−2–10−3 bar) but there appears a contribution of bulk diffusion under high p(O2) in the film electrode at any given temperature. The change of the RDS was also confirmed using isotope exchange depth profile method where a significant change in the oxygen profile in the film electrode was observed. This is attributed to the rate of the bulk diffusion of O2− which is almost constant when the oxygen nonstoichiometry of LaNi0.6Co0.4O3-δ is small, whereas the surface reaction rate strongly depends on p(O2). At low p(O2), the surface reaction is slower than the bulk diffusion, so that the potential drop on the surface of the electrode film is large. In contrast, at high p(O2), the surface reaction is faster than the bulk diffusion where the potential decay is sluggish inside the film electrode.
AB - The rate-determining step (RDS) in the oxygen reduction process on a LaNi0.6Co0.4O3-δ film electrode was analyzed using electrochemical impedance spectroscopy in varied temperatures (873–1073 K), oxygen partial pressures (1–10−3 bar), and DC bias. From the evaluation of the area-specific interfacial conductivity, σE, and chemical capacitance, CE, it is suggested that the RDS is surface reaction under low p(O2) (10−2–10−3 bar) but there appears a contribution of bulk diffusion under high p(O2) in the film electrode at any given temperature. The change of the RDS was also confirmed using isotope exchange depth profile method where a significant change in the oxygen profile in the film electrode was observed. This is attributed to the rate of the bulk diffusion of O2− which is almost constant when the oxygen nonstoichiometry of LaNi0.6Co0.4O3-δ is small, whereas the surface reaction rate strongly depends on p(O2). At low p(O2), the surface reaction is slower than the bulk diffusion, so that the potential drop on the surface of the electrode film is large. In contrast, at high p(O2), the surface reaction is faster than the bulk diffusion where the potential decay is sluggish inside the film electrode.
KW - Chemical capacitance
KW - Film electrode
KW - Isotope exchange
KW - Rate-determining step
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U2 - 10.1007/s10008-018-3935-x
DO - 10.1007/s10008-018-3935-x
M3 - Article
AN - SCOPUS:85045070067
VL - 22
SP - 2227
EP - 2235
JO - Journal of Solid State Electrochemistry
JF - Journal of Solid State Electrochemistry
SN - 1432-8488
IS - 7
ER -