An investigation on strontium doped Sm2NiO4+δ cathode for intermediate temperature solid oxide fuel cells

The Sm2−xSrxNiO4+δ when x = 0.4-1.0 solid solutions are synthesized by combustion followed by sintering at 1100 °C for 10 h, yield crystallite size in the range 73-82 nm. The single-phase Sm2−xSrxNiO4+δ are of orthorhombic and tetragonal crystal structures when x = 0.4-0.7 and x = 0.8-1.0, respectively. The maximum electronic conductivity (σ = 0.361 S cm−1 at 640 °C) for Sm1.5Sr0.5NiO4+δ is due to the extrinsic defects. The decrease in conductivity when x > 0.5 is attributed to the formation of electrically neutral clusters. The narrow particle size distribution with mean particle size 423 ± 11 nm, of Sm1.5Sr0.5NiO4+δ is obtained by ball milling the ink/slurry at 300 revolutions per minute (rpm) for 1 h. The minimum area specific resistance (ASR) of 2.7 Ω cm2 at 700 °C is obtained when x = 0.5, and is attributed to uniform superfine grains and optimum porosity of cathode.