Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305357
Title: Calorimetric and related studies of disorder in solid electrolyte and similar materials
Author: Hall, Peter Gerald
Awarding Body: De Montfort University
Current Institution: De Montfort University
Date of Award: 1984
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Abstract:
described. The calorimeter is of traditional design but the control system is new, based around a Commodore PET microcomputer. The first heat capacity measurements made, on a sample of Calorimetry Conference Sapphire between 77 and 315 K, indicated an accuracy within 1%. Since that time substantial improvements to the control system have been made. For most samples studied experimental precision is considerably better than 1%. Even with drift periods as long as 5-6 h, precision is better than 2%. The first heat capacity studies by adiabatic calorimetry are reported for crystalline Ag614W04 and AgI3IgW20S. Both exhibit three transitions, two first order near 19S and 246 K and a continuous transition with a maximum near 275 K. These findings are discussed in relation to previous studies of these electrolytes. The glassy electrolyte Ag13IgW20S shows no evidence of these transitions, and non-equilibrium behaviour is apparent. The heat capacity differs significantly from the literature data for the glass Ag 7 1 4 As0 4 • A continuous transition has been found in [NMe4]2Ag13115 near 155 K. To allow a comparison of the electrolyte heat capacities with those of their components, a heat capacity study of Ag 2 W0 4 was carried out. Three samples were used: finely divided precipitate; crushed pellets formed from the powder; and a crushed cooled melt. Equilibration times for the first two were long, 1-2 h and 5-6 h respectively. This is in line with published data for another powdered solid. The behaviour of the crushed cooled melt was normal. A small heat capacity anomaly is apparent at 277 K though this may result from slight breakdown of Ag 2 W0 4 during melting or from impurity phases present in the original precipitate. Some results of an extended x-ray absorption fine structure study of a copper(I) electrolyte are presented which suggest that in these systems electrolyte modification occurs during cell discharge.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.305357  DOI: Not available
Keywords: 530 ; Physics Physics
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