The electrical conducting, thermal expansion and electrochemical properties of La1.8Sr0.2NiO4+δ were investigated in view of cathode utilization for intermediate temperature solid oxide fuel cells. La1.8Sr0.2NiO4+δ exhibited electrical conductivities of 96–114 S cm−1 at 600–800 °C and a thermal expansion coefficient of 12.6 × 10−6 K−1 between 50 and 1000 °C. Based on a three-electrode half cell, the electrode properties of La1.8Sr0.2NiO4+δ were diagnosed using electrochemical impedance spectroscopy and chronopotentiometry techniques. Moreover, the performance of an anode-supported single cell with La1.8Sr0.2NiO4+δ cathode was examined. Compared with La2NiO4+δ, La1.8Sr0.2NiO4+δ manifested improved electrode properties under cathodic polarization conditions while showing an analogous catalytic activity under open-circuit conditions. At 800 °C in air, La1.8Sr0.2NiO4+δ electrode displayed a polarization resistance of 0.41 Ω cm2 and a cathodic overpotential of 90 mV at 200 mA cm−2. The anode-supported single cell with La1.8Sr0.2NiO4+δ cathode achieved a maximum power density of 520 mW cm−2 at 800 °C in hydrogen fuel.