Effects of ionic conductivities of zirconia electrolytes on polarization properties of platinum anodes in solid oxide fuel cells

Journal Article · Thu Mar 09 04:00:00 EST 1995 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100010a044· OSTI ID:6463055

Uchida, Hiroyuki; Yoshida, Manabu; Watanabe, Masahiro ^[1]

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1. Yamanashi Univ., Kofu (Japan)

To find a clue for the design of high-performance electrodes for solid oxide fuel cells (SOFCs), the polarization properties of Pt electrodes attached to zirconia electrolytes with various ionic conductivities were investigated at 800-1000[degree]C. The IR-free anodic polarization in hydrogen was greatly affected by the ionic conductivity of the electrolyte, and it obeyed the Tafel equation. The exchange current density increased in proportion to the square of the ionic conductivity for all electrolytes operated at 800-1000[degree]C, while the transfer coefficient (n[alpha][sub o] = 2) was independent of the temperature and of the conductivity of electrolytes. According to our analysis, the rate-determining step is not a simple electron transfer from oxide ions but a recombination step involving discharged oxygen atoms adsorbed on the Pt electrode/electrolyte interface; an increase in the rate of transport of oxide ions to the interface, for example, by using an electrolyte with higher-ionic conductivity, reduces the anodic overpotential greatly. 34 refs., 6 figs., 1 tab.

• OSTI ID: 6463055
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 99:10; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300503* -- Fuel Cells-- Materials
Components
& Auxiliaries
300505 -- Fuel Cells-- Electrochemistry
Mass Transfer & Thermodynamics
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400400 -- Electrochemistry
ANODES
CHALCOGENIDES
CHARGED-PARTICLE TRANSPORT
CURRENT DENSITY
DIRECT ENERGY CONVERTERS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROCHEMICAL CELLS
ELECTRODES
ELECTROLYTES
ELEMENTS
FUEL CELLS
IONIC CONDUCTIVITY
METALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM
PLATINUM METALS
POLARIZATION
RADIATION TRANSPORT
SOLID ELECTROLYTE FUEL CELLS
SOLID ELECTROLYTES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES