The solid solution range of a perovskite was investigated, and the O-ion conductivities of the various compositions were measured (table 4). It was found that the solubility of Sr could be extended by adding Mg ions in order to establish a balance of the O vacancies which were associated with A and B sites. In this way, the Sr limit of the solid solution was increased to more than 20% of the La content. Doping with Sr or Mg enhanced the O-ion conductivity. However, whereas Sr doping led to a decrease in activation energy with increasing concentration, Mg additions led to an increase in activation energy with increasing Mg content. The composition, La0.8Sr0.2Ga0.9Mg0.1O2.85, was found to exhibit the highest conductivity, apart from CeO2-based electrolytes, at temperatures below 700C, whereas the composition, La0.8Sr0.2Ga0.85Mg0.15O2.825, exhibited the highest conductivity, apart from Bi2O3, at temperatures above 700C.

P.Huang, A.Petric: Journal of the Electrochemical Society, 1996, 143[5], 1644-50

 

 

 

Table 4

Ionic Conductivity of La1-xSrxGa1-yMgyO3

 

 

x

 

y

 

600C (S/cm)

 

800C (S/cm)

 

Q (eV)

 

 

0.1

 

0

 

0.00897

 

0.0365

 

0.81

0.1

0.05

0.0220

0.0885

0.87

0.1

0.1

0.0253

0.107

1.02

0.1

0.15

0.0220

0.117

1.06

0.1

0.2

0.0198

0.121

1.13

0.1

0.25

0.0192

0.126

1.17

0.15

0.05

0.0193

0.0811

0.918

0.15

0.1

0.0280

0.121

0.98

0.15

0.15

0.0259

0.131

1.03

0.15

0.2

0.0211

0.124

1.09

0.2

0.05

0.0212

0.0913

0.874

0.2

0.1

0.0292

0.128

0.950

0.2

0.15

0.0285

0.140

1.06

0.2

0.2

0.0221

0.137

1.15

0.25

0.1

0.0172

0.0448

1.02

0.25

0.15

0.0191

0.104

1.12