Abstract
An effect of strontium ion doping on the structural, thermal, morphological and electrical properties of a co-doped lanthanum manganite system, La
1−
x
Sr
x
Mn
0.85Fe
0.05Co
0.05Ni
0.05O
3+
δ
(
x
=
0–0.4
mole) is investigated for the solid oxide fuel cell cathode application. The submicron and rhombohedral structured sample, synthesized by the Pechini method, exhibited a decrease in the unit cell volume with increasing
x. The thermogravimetry study portrayed nearly fivefold weight loss for a sample with
x
=
0.3
mole relative to the La
0.75Sr
0.25MnO
3+
δ
and suggested an improvement in the concentration of the oxygen vacancy for ion migration due to the co-doping effect. It also showed sufficiently high electrical conductivity (∼76
S
cm
−1) at 650
°C along with a low activation energy (∼0.15
eV), a comparable coefficient of thermal expansion (∼12.1
×
10
−6
°C
−1) and a chemical compatibility with the solid electrolytes. The results were explained using the defect models.