Nanoporous nickel thin film anode optimization for low-temperature solid oxide fuel cells

Abstract

Thin film solid oxide fuel cells (TFeSOFCs) having anodeesubstrate nanostructure that wasoptimized for the low-temperature operation were fabricated. Nickel thin film anodes withfour different anode thicknesses were deposited on anodic aluminum oxide templates,nanoporous substrates having two different pore sizes, by the sputtering method. Subse-quently, a yttria-stabilized zirconia (YSZ) electrolyte and platinum cathode were depositedon them, which completed the entire fuel cell structure. The anode nanostructure of fuelcells in six combinations was analyzed by the cross-sectional view, surface microscopymethod, and three-dimensional morphology observation. Those investigations enabled theanode nanostructure to be identified, such as the anode porosity and the roughness of theinterface between anodes and electrolytes. Then, the six TFeSOFCs were electrochemicallycharacterized in a 500C operating environment. The maximum power densities wereobtained through the ieVeP curves, and the highest performance of 294.1 mW/cm2wasmeasured in the cell having a combination of 200 nmesized porous aluminum anodicoxide (AAO) and 1200 nmethick Ni anode. This showed up to 20.1% improvement over theother cells. EIS analysis showed that the optimized ohmic and faradaic resistance origi-nated from each part of the unique TFeSOFC structure.