Direct methane fuel cell with La2Sn2O7–Ni–Gd0.1Ce0.9O1.95 anode and electrospun La0.6Sr0.4Co0.2Fe0.8O3−δ–Gd0.1Ce0.9O1.95 cathode

Abstract

La₂Sn₂O₇ nano-powder is synthesized by co-precipitation method. La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) and Gd_0.1Ce_0.9O_1.95 (GDC) composite fibers are fabricated by electrospinning. Scanning electron microscopy (SEM) images show highly increased triple phase boundary (TPB) sites and pores in the electrospun cathode. The interfacial resistance of the electrospun cathode is reduced by 0.2 Ω cm² compared to the conventional cathode at 650 °C. When dry methane fuel is fed to the anode, the reduction rate of the power density of the La₂Sn₂O₇–Ni–GDC anode-supported cell significantly decreases compared to that of the Ni–GDC anode-supported cell at 650 °C. The anode resistance in the low frequency range (∼3 Hz) associated with methane conversion shows a remarkable difference between the La₂Sn₂O₇–Ni–GDC and Ni–GDC anode. Temperature-programmed reduction (TPR) analysis reveals the La₂Sn₂O₇ catalyst is effective for the methane oxidation reaction at 650 °C. The Fuel cell in this study manifests a maximum power density of 1.02 W cm⁻² and 0.94 W cm⁻² at 650 °C in hydrogen and dry methane atmosphere, respectively. Also, no carbon deposition existed on the La₂Sn₂O₇–Ni–GDC anode after operating.