Optimizing Nickel Doping in La

Solid Oxide Fuel Cells (SOFCs) are among the most efficient and environmentally friendly technologies. The cathode is a crucial component of SOFC system, a high-performance cathode material must exhibit high conductivity, good catalytic activity and structural stability toward the oxygen reduction reaction (ORR). In this study, the sol-gel method was used to prepare La0.7Sr0.3Ti0.15Fe0.85-xNixO3-δ (x=0, 0.1, 0.2, 0.3) powders and investigated for its potential as a cathode material for LT-SOFC. The phase, crystal structure, microstructure, morphology, and conductivity were characterized with varying Ni compositions. X-ray diffraction characterization reveals orthorhombic perovskite structure with space group Pnma. With increasing Ni content, the unit cell volume initially expanded but slightly contracted at x = 0.3, attributed to the smaller ionic radius of Ni3+ compared to Fe2+. The LSTFN powders exhibit an interconnected network-like morphology consisting of fine particles and pores. All samples showed good homogeneity, uniform particle distribution, and high porosity. Electrical conductivity increased with Ni doping, reaching a maximum value of 8.97 S∙m-1 at room temperature for x = 0.2, more than twice that of the undoped sample. Further Ni content at x = 0.3, conductivity decreased may due to unit cell contraction. Therefore, the Ni composition of x = 0.2 is identified as the optimal concentration for enhancing performance. These results suggest that LSTFN is a potential cathode material for LT-SOFC.