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Title: Thermodynamic properties of calcium-bismuth alloys determined by emf measurements

Abstract

The thermodynamic properties of Ca-Bi alloys were determined by electromotive force (emf) measurements to assess the suitability of Ca-Bi electrodes for electrochemical energy storage applications. Emf was measured at ambient pressure as a function of temperature between 723 K and 1173 K using a Ca(s)vertical bar CaF2(s)vertical bar Ca(in Bi) cell for twenty different Ca-Bi alloys spanning the entire range of composition from chi(Ca) = 0 to 1. Reported are the temperature-independent partial molar entropy and enthalpy of calcium for each Ca-Bi alloy. Also given are the measured activities of calcium, the excess partial molar Gibbs energy of bismuth estimated from the Gibbs-Duhem equation, and the integral change in Gibbs energy for each Ca-Bi alloy at 873 K, 973 K, and 1073 K. Calcium activities at 973 K were found to be nearly constant at a value a(Ca) = 1 x 10(-8) over the composition range chi(Ca) = 0.32-0.56, yielding an emf of similar to 0.77 V. Above chi(Ca) = 0.62 and coincident with Ca5Bi3 formation, the calcium activity approached unity. The Ca-Bi system was also characterized by differential scanning calorimetry over the entire range of composition. Based upon these data along with the emf measurements, a revised Ca-Bi binarymore » phase diagram is proposed. (C) 2011 Elsevier Ltd. All rights reserved.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1211033
DOE Contract Number:  
DE-AR0000047
Resource Type:
Journal Article
Journal Name:
Electrochimica Acta
Additional Journal Information:
Journal Volume: 60; Journal ID: ISSN 0013-4686
Country of Publication:
United States
Language:
English

Citation Formats

Kim, H, Boysen, DA, Bradwell, DJ, Chung, BC, Jiang, K, Tomaszowska, AA, Wang, KL, Wei, WF, and Sadoway, DR. Thermodynamic properties of calcium-bismuth alloys determined by emf measurements. United States: N. p., 2012. Web. doi:10.1016/j.electacta.2011.11.023.
Kim, H, Boysen, DA, Bradwell, DJ, Chung, BC, Jiang, K, Tomaszowska, AA, Wang, KL, Wei, WF, & Sadoway, DR. Thermodynamic properties of calcium-bismuth alloys determined by emf measurements. United States. doi:10.1016/j.electacta.2011.11.023.
Kim, H, Boysen, DA, Bradwell, DJ, Chung, BC, Jiang, K, Tomaszowska, AA, Wang, KL, Wei, WF, and Sadoway, DR. Sun . "Thermodynamic properties of calcium-bismuth alloys determined by emf measurements". United States. doi:10.1016/j.electacta.2011.11.023.
@article{osti_1211033,
title = {Thermodynamic properties of calcium-bismuth alloys determined by emf measurements},
author = {Kim, H and Boysen, DA and Bradwell, DJ and Chung, BC and Jiang, K and Tomaszowska, AA and Wang, KL and Wei, WF and Sadoway, DR},
abstractNote = {The thermodynamic properties of Ca-Bi alloys were determined by electromotive force (emf) measurements to assess the suitability of Ca-Bi electrodes for electrochemical energy storage applications. Emf was measured at ambient pressure as a function of temperature between 723 K and 1173 K using a Ca(s)vertical bar CaF2(s)vertical bar Ca(in Bi) cell for twenty different Ca-Bi alloys spanning the entire range of composition from chi(Ca) = 0 to 1. Reported are the temperature-independent partial molar entropy and enthalpy of calcium for each Ca-Bi alloy. Also given are the measured activities of calcium, the excess partial molar Gibbs energy of bismuth estimated from the Gibbs-Duhem equation, and the integral change in Gibbs energy for each Ca-Bi alloy at 873 K, 973 K, and 1073 K. Calcium activities at 973 K were found to be nearly constant at a value a(Ca) = 1 x 10(-8) over the composition range chi(Ca) = 0.32-0.56, yielding an emf of similar to 0.77 V. Above chi(Ca) = 0.62 and coincident with Ca5Bi3 formation, the calcium activity approached unity. The Ca-Bi system was also characterized by differential scanning calorimetry over the entire range of composition. Based upon these data along with the emf measurements, a revised Ca-Bi binary phase diagram is proposed. (C) 2011 Elsevier Ltd. All rights reserved.},
doi = {10.1016/j.electacta.2011.11.023},
journal = {Electrochimica Acta},
issn = {0013-4686},
number = ,
volume = 60,
place = {United States},
year = {2012},
month = {1}
}