Li/Na Modified Ni-SDC Anode for Methane-Fueled Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) have the potential to direct use hydrocarbon fuels without pretreatment due to its high operating temperature [1]. The most common used nickel/yttria-stabilized zirconia (Ni/YSZ) anodes have showed excellent performance in H₂ fuel, however, there is serious carbon deposition when hydrocarbon fuels are used. In recent years, great efforts have been devoted to develop alternative anodes to alleviate carbon deposition issue encountered in Ni-based cermets anode. However, the performance of the proposed alternative anode materials is still not satisfactory yet when hydrocarbon fuels are used. Alkali or alkaline earth oxides have been used to enhance the activity of catalysts for reforming [2] and water-gas shift reactions [3]. In this work, a facile chemically lithium/sodium insertion method has been developed to prepare Li/Na doped-NiO composites (Li/Na-NiO). The single cells were fabricated with a Li/Na doped NiO-Ce_0.8Sm_0.2O_1.9 (SDC) composite anode screened on a 250um La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-d (LSGM) electrolyte and a composite cathode consisting of Sr_0.95Ce_0.05CoO_3-d and SDC (30wt%). When CH₄ was used as fuel, the peak power density of the cells with the Li and Na doped NiO anode reaches about 126 mW cm^-2 and 106mW cm^-2 at 800^oC, respectively. Compared with that of the cell with the pristine NiO-SDC anode, the cells with Li/Na doped NiO anode material shows that it gives much higher open circuit voltage (OCV) and better long-term stability at 800^oC than that of the cell with the pristine Ni-based anode. The preliminary results demonstrate that the Li/Na doped NiO anode materials are promising alternative anode for hydrocarbon-fueled solid oxide fuel cells.