The Electrical Conductivity of β ‐ PbF2

Abstract

The electrolytic properties of pure/~-PbF~ were studied by a-c conductivity measurements and Hebb-Wagner d-c polarization experiments as a function of fluorine pressure and temperature. The partial ionic and electronic conductivities of ~-PbF2 were determined over a range of fluorine pressure and temperature. Because of the introduction of p-type electronic conduction, the electrolytic domain of ~-PbF~ is truncated at high values of PF2, with PF~ = 10 -~1 arm at 492°C. At low PF2, predominant ionic conduction extends to PF2 for the coexistence of Pb and PbF2.The electrolytic properties of nominally pure and doped p-PbF~ and ~-PbF2 have been extensively investigated recently (1-16). Bonne and Schoonman (13) calculated the temperature dependences of the concentrations and mobilities of the interstitial fluoride ions and anion vacancies based on their a-c conductivity measurements of pure and doped p-PbF2 and existing literature data. Their results indicated that interstitial fluoride ions are the principal mobile species in pure ~-PbF2 for temperatures greater than 300°C. Hebb-Wagner polarization experiments have also been conducted by many authors to elucidate the electronic conductivity in PbFe. Kennedy et al. (4) reported that the electronic conductivity of pure ~-PbF~ at 150°C was p-type. At 25°C Kennedy and Miles (12) could not specify whether the electronic current in fl-PbF2 was carried by electrons or 'holes. Benz (10) found that pure ~-PbF~ was essentially an n-type conductor from 400 ° to 600°C. Schoonman et al. (8) also found an n-type conductor for pure ~-PbF2 single crystal from 52 ° to 137°C. Joshi and Liang (9) reported that ~-PbFe is a p-type conductor.Both ~-PbF2 and ~-PbF2 are known to be predominant ionic conductors. To elucidate the ionic domain (17, 18) of PbF2, the determination of the range of log PF2 beyond which electronic conduction becomes appreciable is studied here. Previous studies did not include several well-defined fluorine activities in conductivity studies on PbF2. The present study consists of measurements of the total a-c conductivity, together with the measurements of the partial conductivity for electrons and electron holes as a function of fluorine activity. These results define the limits for the electrolytic domain for PbFe. Hebb-Wagner polarization studies of ~-PbF2 also clarify the controversial results regarding n-type conduction as the predominant electronic conduction mode.

An Electrochemically Regenerative Hydrogen‐Chlorine Energy Storage System: A Study of Mass and Heat Balances

“…Using Eq. [19], these values have been calculated as a function of overvoltage for both scheme I and scheme II and are shown in Fig. 9.…”

The Unique Case of Tin(ii) Fluoride Containing Unexpected Substitutional Solid Solutions: Local Structure Versus Global Structure

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