Preparation and electrochemical characterization of Ruddlesden-Popper oxide La₄Ni₃O₁₀ cathode for IT-SOFCs by sol-gel method

La₄Ni₃O₁₀ oxide was synthesized as a cathode material for intermediate-temperature solid oxide fuel cells by a facile sol-gel method using a nonionic surfactant (EO)106(PO)70(EO)106 tri-block copolymer (F127) as the chelating agent. The crystal structure, electrical conductivity, and electrochemical properties of La₄Ni ₃O₁₀ were investigated by X-ray diffraction, DC four-probe method, electrochemical impedance spectra, and I-V measurements. The La ₄Ni₃O₁₀ cathode showed a significantly low polarization resistance (0.26 Ω cm²) and cathodic overpotential value (0.037 V at the current density of 0.1 A cm^-2) at 750 C. The results measured suggest that the diffusion process was the rate-limiting step for the oxygen reduction reaction. The La₄Ni₃O ₁₀ cathode revealed a high exchange current density value of 62.4 mA cm^-2 at 750 C. Furthermore, an anode-supported single cell with La₄Ni₃O₁₀ cathode was fabricated and tested from 650 to 800 C with humidified hydrogen (∼3 vol% H₂O) as the fuel and the static air as the oxidant. The maximum power density of 900 mW cm^-2 was achieved at 750 C.