Asymmetric proton conducting oxide membranes and fuel cells prepared by aqueous tape casting

Asymmetric proton conducting membranes and fuel cells based on Sr-doped LaNbO4 have been prepared. Porous supports were made by aqueous tape casting, where the porosity was ensured by adding pore fillers. The viscosity of the slips was found in the range 410–500 cP at a shear rate of 50 s− 1, depending on type of pore filler. Particle size and particle size distribution of the slips were investigated by wet-SEM technique, and demonstrating sub-micron size powders well dispersed in the slips. Carbon black was shown to be the best pore filler with connected pores and only open porosity. The O2-flux was measured to 13.8 ml min− 1 cm− 2 mm for a 42% porous substrate in an O2-He gradient, normalized with respect to the thickness. Dense asymmetric membranes were deposited on porous substrates by spray coating. Fuel cells were prepared by spray coating of electrolyte and cathode on an anode support made by tape casting.