Theory of thermocells: Transported entropies, and heat of transfer in sulfate mixtures

Journal Article · Sun May 01 04:00:00 EDT 1994 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2054902· OSTI ID:7036976

Grimstvedt, A; Ratkje, S K; Foerland, T ^[1]

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1. Univ. of Trondheim (Norway). Dept. of Physical Chemistry

Knowledge about transported entropies, and heats of transfer, is important for calculation of local heat effects in electrolysis cells, fuel cells, and thermoelectric generators. The transported entropy of silver ion, S*[sub Ag], and the heat of transfer, q*[sub 2], for Ag[sub 2]SO[sub 4], have been calculated from electromotive force (EMF) measurements in the cell Ag(T[sub 1])[vert bar]Ag[sub 2]SO[sub 4]-Li[sub 2]SO[sub 4][vert bar]Ag(T[sub 2]). Results give S*[sub Ag], = 102 [+-] 6 J/K mol when 0.1 < xAg[sub 2]SO[sub 4]. From this the authors derived S[sup 2[minus]][sub 4] = 220 JK [sup [minus]1] mol[sup [minus]1] in pure silver sulfate and S[sub Li+] = 54 J/K mol in lithium-silver sulfate mixtures. For smaller mole fractions of Ag[sub 2]SO[sub 4], S*[sub Ag], increases. The heat of transfer, q*[sub 2], is negative and varies with composition. The sign indicates that Ag[sub 2]SO[sub 4] is enriched on the hot side. The Thomson coefficient for molten pure AgSO[sub 4] is [tau][sub Ag [sup +]] = 30 J/K mol. From this the authors derive [tau]SO[sup 2[minus]][sub 4] = 140 J/K mol. Kinetic and thermodynamic models for the transported entropy and heat of transfer are discussed. Some models can be rejected.

• OSTI ID: 7036976
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 141:5; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
ALKALI METAL COMPOUNDS
ELECTROCHEMICAL CELLS
ENERGY TRANSFER
HEAT TRANSFER
LITHIUM COMPOUNDS
LITHIUM SULFATES
MATHEMATICAL MODELS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SILVER COMPOUNDS
SILVER SULFATES
SULFATES
SULFUR COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS