CHEMICAL STUDY AND IONIC CONDUCTIVITY

OF NEW DIPHOSPHATES CONTAINING Ag+ AND Li+

 

M. Bouziane1*, M. Taibi2, A. Boukhari1

1 Laboratoire de Chimie du Solide Appliquée, Laboratoire Associé Francophone N°501,

Faculté des Sciences, Avenue Ibn Batouta, BP 1014, Rabat - Morocco

2 Laboratoire de Physico -Chimie des Matériaux, LAF 502, Ecole Normale Supérieure BP 5118 Rabat - Morocco.

* Corresponding author. E-mail: bouzianemeryem@yahoo.fr

Received: 21 November 2007; revised version accepted: 28 December 2007

 

Abstract

     The new silver and lithium phosphates of composition Co1-x/2Cu1-x/2Ag2xP2O7 (0 = x = 0.25) and Co0.95Cu0.95Li0.2P2O7 were prepared by solid state reaction in air atmosphere. The identity of the compounds was confirmed by X-Ray diffraction. The ionic conductivity ascribed to the Ag+ and Li+ ions motion was studied by impedance measurements. The activation energy of   Co1-x/2Cu1-x/2Ag2xP2O7 (0 = x = 0.25) is nearly the same (0.69 – 0.70 eV).Their modulus spectrum shows de non - Debye behaviour and the conductivity mechanism can be assigned to hopping motion of the mobile Ag ions. The substitution of silver by lithium in the composition x = 0.1 decrease the value of activation energy from 0.69 to 0.33 eV and increases s at 150°C from 4.4 10-7 to 6.93 10-6 O -1 cm-1. So, Co0.95Cu0.95Li0.2P2O7 is better conductor than Co0.95Cu0.95Ag0.2P2O7.

 

Keywords: Diphosphates; Ionic conductivity; Ag+ ion conduction; Li+ ion conduction;  Activation energy; Modulus spectrum.

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