Thermodynamic properties of calcium-bismuth alloys determined by emf measurements

Hojong Kim; Dane A. Boysen; David J. Bradwell; Brice Chung; Kai Jiang; Alina A. Tomaszowska; Kangli Wang; Weifeng Wei; Donald R. Sadoway

doi:10.1016/j.electacta.2011.11.023

Thermodynamic properties of calcium-bismuth alloys determined by emf measurements

Hojong Kim, Dane A. Boysen, David J. Bradwell, Brice Chung, Kai Jiang, Alina A. Tomaszowska, Kangli Wang, Weifeng Wei, Donald R. Sadoway

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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)CaF ₂(s)Ca(in Bi) cell for twenty different Ca-Bi alloys spanning the entire range of composition from x _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 of a _Ca = 1 × 10 ^-8 over the composition range x _Ca = 0.32-0.56, yielding an emf of ∼0.77 V. Above x _Ca = 0.62 and coincident with Ca ₅Bi ₃ 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.

Original language	English (US)
Pages (from-to)	154-162
Number of pages	9
Journal	Electrochimica Acta
Volume	60
DOIs	https://doi.org/10.1016/j.electacta.2011.11.023
State	Published - Jan 15 2012

All Science Journal Classification (ASJC) codes

Chemical Engineering(all)
Electrochemistry

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10.1016/j.electacta.2011.11.023

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@article{816303f517554b27a81696ef467d6430,

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)CaF 2(s)Ca(in Bi) cell for twenty different Ca-Bi alloys spanning the entire range of composition from x 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 of a Ca = 1 × 10 -8 over the composition range x Ca = 0.32-0.56, yielding an emf of ∼0.77 V. Above x Ca = 0.62 and coincident with Ca 5Bi 3 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.",

author = "Hojong Kim and Boysen, {Dane A.} and Bradwell, {David J.} and Brice Chung and Kai Jiang and Tomaszowska, {Alina A.} and Kangli Wang and Weifeng Wei and Sadoway, {Donald R.}",

note = "Funding Information: The authors would like to thank Professors George Kipouros and Geir Martin Haarberg for their helpful advice on making emf measurements in cells fitted with solid electrolytes. The financial support of the US Department of Energy , Advanced Research Projects Agency-Energy (Award No. DE-AR0000047) and TOTAL, S.A. is gratefully acknowledged.",

year = "2012",

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day = "15",

doi = "10.1016/j.electacta.2011.11.023",

language = "English (US)",

volume = "60",

pages = "154--162",

journal = "Electrochimica Acta",

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TY - JOUR

T1 - Thermodynamic properties of calcium-bismuth alloys determined by emf measurements

AU - Kim, Hojong

AU - Boysen, Dane A.

AU - Bradwell, David J.

AU - Chung, Brice

AU - Jiang, Kai

AU - Tomaszowska, Alina A.

AU - Wang, Kangli

AU - Wei, Weifeng

AU - Sadoway, Donald R.

N1 - Funding Information: The authors would like to thank Professors George Kipouros and Geir Martin Haarberg for their helpful advice on making emf measurements in cells fitted with solid electrolytes. The financial support of the US Department of Energy , Advanced Research Projects Agency-Energy (Award No. DE-AR0000047) and TOTAL, S.A. is gratefully acknowledged.

PY - 2012/1/15

Y1 - 2012/1/15

N2 - 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)CaF 2(s)Ca(in Bi) cell for twenty different Ca-Bi alloys spanning the entire range of composition from x 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 of a Ca = 1 × 10 -8 over the composition range x Ca = 0.32-0.56, yielding an emf of ∼0.77 V. Above x Ca = 0.62 and coincident with Ca 5Bi 3 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.

AB - 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)CaF 2(s)Ca(in Bi) cell for twenty different Ca-Bi alloys spanning the entire range of composition from x 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 of a Ca = 1 × 10 -8 over the composition range x Ca = 0.32-0.56, yielding an emf of ∼0.77 V. Above x Ca = 0.62 and coincident with Ca 5Bi 3 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.

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DO - 10.1016/j.electacta.2011.11.023

M3 - Article

AN - SCOPUS:84655167824

VL - 60

SP - 154

EP - 162

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

ER -

Thermodynamic properties of calcium-bismuth alloys determined by emf measurements

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