The authors have determined the thermoelectric power epsi of the high ionic conductivity glass (AgI) 0.79(Ag 2O.B 2O 3) 0.21; epsi is negative throughout the investigated T range, 320-500K. The heat of transport of the mobile Ag +, QAg, taken as the slope of the straight line fitting epsi versus 1/ T, is quite lower than the activation energy obtained from conductivity data, viz. QAg=2.81 kcal mole -1< Eact=4.34 kcal mole -1. To circumvent this discrepancy, the analysis of the experimental data is carried out as follows: (i) it is supposed that QAg= Eact in agreement with the free ion theory for solid electrolytes; (ii) the vibrational part of the silver ion entropy, S(Ag +,vib), is assumed to be equal to the entropy of silver, S(Ag); (iii) on the ground of a structural model for this kind of glasses, the ideal configurational entropy of the mobile Ag +, S(Ag +,conf) id, is evaluated through a statistical approach. The ideal ionic entropy is defined as S(Ag +) id={ S(Ag +,vib)+ S(Ag +,conf) id}; (iv) the difference { S(Ag + ) exp- S(Ag +) id} is viewed as an excess entropy and is described according to the classical model of the regular solutions
Thermoelectric power of the vitreous electrolyte (AgI) 0.79(Ag 2O.B 2O 3) / A: SCHIRALDI, E. PEZZATI, P. ROSSI. - In: SOLID STATE IONICS. - ISSN 0167-2738. - 7:3(1982 Oct), pp. 257-261. [10.1016/0167-2738(82)90057-1]
Thermoelectric power of the vitreous electrolyte (AgI) 0.79(Ag 2O.B 2O 3)
A. SchiraldiPrimo
;
1982
Abstract
The authors have determined the thermoelectric power epsi of the high ionic conductivity glass (AgI) 0.79(Ag 2O.B 2O 3) 0.21; epsi is negative throughout the investigated T range, 320-500K. The heat of transport of the mobile Ag +, QAg, taken as the slope of the straight line fitting epsi versus 1/ T, is quite lower than the activation energy obtained from conductivity data, viz. QAg=2.81 kcal mole -1< Eact=4.34 kcal mole -1. To circumvent this discrepancy, the analysis of the experimental data is carried out as follows: (i) it is supposed that QAg= Eact in agreement with the free ion theory for solid electrolytes; (ii) the vibrational part of the silver ion entropy, S(Ag +,vib), is assumed to be equal to the entropy of silver, S(Ag); (iii) on the ground of a structural model for this kind of glasses, the ideal configurational entropy of the mobile Ag +, S(Ag +,conf) id, is evaluated through a statistical approach. The ideal ionic entropy is defined as S(Ag +) id={ S(Ag +,vib)+ S(Ag +,conf) id}; (iv) the difference { S(Ag + ) exp- S(Ag +) id} is viewed as an excess entropy and is described according to the classical model of the regular solutionsPubblicazioni consigliate
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