Ionic conductivity properties of ZrF4-BaF2-LaF3-AF (A = Li, Na) glasses

195

P15

IONIC CONDUCTIVITY (A = Li, Na) GLASSES

PROPERTIES

OF ZrF,-BaF,-LaF,-AF

J. M. Rgau, J. Senegas Laboratoire 33405

de Chimie

Talence

du Solide du CNRS, UniversitC

de Bordeaux

I,

Cedex (France)

M. Rojo Institute

de Ciencias

de Materiales,

C.S.I.C. Madrid

(Spain)

M. Poulain Laboratoire

de Chimie

minkrale

D. L.A. 254, Rennes

(France)

and H. Kahnt Department

of Chemistry,

A comparative

Friedrich-Schiller-University,

study

of

electrical

Jena (G.D.R.)

properties

of

2rF4(0.62-0.4x)BaF2(0.30-0.5x~LaF3(0.08-0.1x)AF(x~ has been carried

out

A minimum has with

been

of

detected

when

the glasses

in the Li-low from

the

belonging

A

activation

energy only

atomic

bound Li/F

ratio

to

a maximum is equal

Na,

on

the

increases

of

to

glasses

activation

=

0.07.

energy By analogy

-ThF4-LiF system, it is proposed that 2 (Li/F & 0.07) transport properties result + Li for high mobile Li and F- ions and

domain of

contrary, with

conductivity increasing

+

rate.

decreases x.

The

regularly

and

electrical properties 23 Na NMR study has A

from the contribution of mobile F- ions. +. ions do not participate in the conductivity

shown that Na

of

(0 < x < 0.30)

to ZrF4-BaF

(Li/F 3 0.07), they depend only on the Li =

series

of AF content.

conductivity

contributions

concentrations

result

a function

concentration

mixed

When

as

ionic

both

(A = Li, Na)

mechanisms.