Thermodynamics and Efficiency of a CuCl(aq)/HCl(aq) Electrolyzer

Derek M. Hall, Nikolay N. Akinfiev, Eric G. Larow, Richard S. Schatz, Serguei N. Lvov

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The high ionic strength and complex speciation of the anolyte solution within the CuCl(aq)/HCl(aq) electrolytic cell have impeded predictions of the energy requirements for the cell's electrolytic reaction at 25 °C and 1 bar. After collecting experimental open circuit potential (OCP) data and comparing the values obtained with predictions from prospective thermodynamic models, an approach to predict thermodynamic values and the overall efficiency was formulated. The compositions of the experimental measurements ranged from 2-2.5 mol of CuCl(aq) with 8-9 mol of HCl(aq) per kilogram of water in anolyte solution and 8-9 mol of HCl(aq) per kilogram of water in catholyte solution. From the OCP data, it was found that activity coefficient and speciation effects were critical in predicting the Gibbs energy, entropy and thermodynamic (intrinsic maximum) efficiency of the electrolytic cell. At equilibrium, all thermodynamic functions of the anolyte redox reactions were the same after activity coefficients and speciation effects were taken into account. The electrochemical reactions' Gibbs energy and entropy were found to be 9700 J/mol and 2.18 J/(mol K) at 25°C and 1 bar, which indicated that the reactions required a small amount of electrical and thermal energy to proceed. With thermodynamic values for the electrolytic reaction and experimental data from a CuCl(aq)/HCl(aq) electrolytic cell, the voltage, current, thermodynamic and overall efficiency were calculated. The overall efficiency ranged from 15 to 95% depending on the current density.

Original languageEnglish (US)
Pages (from-to)70-82
Number of pages13
JournalElectrochimica Acta
Volume143
DOIs
StatePublished - Oct 10 2014

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Thermodynamics
Electrolytic cells
Activity coefficients
Gibbs free energy
Electrolysis
Entropy
Water
Networks (circuits)
Redox reactions
Ionic strength
Thermal energy
Current density
Electric potential
Chemical analysis

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Electrochemistry

Cite this

Hall, Derek M. ; Akinfiev, Nikolay N. ; Larow, Eric G. ; Schatz, Richard S. ; Lvov, Serguei N. / Thermodynamics and Efficiency of a CuCl(aq)/HCl(aq) Electrolyzer. In: Electrochimica Acta. 2014 ; Vol. 143. pp. 70-82.
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Thermodynamics and Efficiency of a CuCl(aq)/HCl(aq) Electrolyzer. / Hall, Derek M.; Akinfiev, Nikolay N.; Larow, Eric G.; Schatz, Richard S.; Lvov, Serguei N.

In: Electrochimica Acta, Vol. 143, 10.10.2014, p. 70-82.

Research output: Contribution to journalArticle

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AU - Hall, Derek M.

AU - Akinfiev, Nikolay N.

AU - Larow, Eric G.

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AU - Lvov, Serguei N.

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