Nanostructured thin solid oxidefuel cells with high power density

Abstract

Nanostructured thin film solid oxide fuel cells (SOFC) have been developed for reduced temperature operation, with high power density, and to be self reforming. A thin film electrolyte (1–2 μm thickness), e.g., yttria-stabilized zirconia (YSZ), is deposited on a nickel foil substrate. The electrolyte thin film is polycrystalline when deposited on a polycrystalline nickel foil substrate, and is (100) textured when deposited on an atomically textured nickel foil substrate. The Ni foil substrate is then converted into a porous SOFC anode by photolithographic patterning and etching to develop porosity. A composite La_0.5Sr_0.5CoO₃ cathode is then deposited on the thin film electrolyte. The resultant thin film hetero structure fuel cells have operated at a significantly reduced temperature: as low as 470 °C, with a maximum power density of 140 mW cm⁻² at 575 °C, and an efficiency of >50%. This drastic reduction in operating temperature for an SOFC now also allows for the use of hydrocarbon fuels without the need for a separate reformer as the nickel anode effectively dissociates hydrocarbons within this temperature range. These nanostructured fuel cells show excellent potential for high power density, small volume, high efficiency fuel cells for power generation applications.