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Test of a dual electrode galvanic cell in binary carbonate melt
Author(s) -
Lee S.,
Staehle R. W.
Publication year - 1998
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/(sici)1521-4176(199801)49:1<7::aid-maco7>3.0.co;2-0
Subject(s) - galvanic cell , dual (grammatical number) , electrode , carbonate , materials science , test (biology) , binary number , metallurgy , geology , chemistry , mathematics , art , literature , arithmetic , paleontology
Basicity of the (Li 0.62 K 0.38 ) 2 CO 3 , the current choice of electrolyte composition for molten carbonate fuel cells (MCFC's ), is defined as — log (a M 2 O ), where M represents an alkali metal and a M 2 Ois the net oxide ion activity. Net oxide ion activity is defined as the sum of the alkali oxides activities dissolved in the melt. To correlate measured cell e.m.f. values with basicity change in the (Li 0.62 K 0.38 ) 2 CO 3 melt, a dual electrode galvanic cell of the following arrangement was tested at 650°C with P CO 2varying above the melt: Au, A—B, CO 2 , O 2 | mullite | A—B, CO 2 , O 2 | ZrO 2 · Y 2 O 3 | O 2 , Au where A—B represents (Li 0.62 K 0.38 ) 2 CO 3 . The response of the cell to P CO 2at constant P O 2can be explained by thermodynamic model, which states that ion transference in the mullite tube is limited to Li* and/or K* and the dual electrode galvanic cell voltage is a direct measure of Δa Li 2 Oor Δa K 2 Ofor pure (Li 0.62 K 0.38 ) 2 CO 3 melt at constant P O 2.