Thermomechanical challenges place restrictions on the choice of fast ion conductors that may be implemented as free standing electrolyte membranes for low temperature solid oxide fuel cells. In order to expand the possible choices, mechanical and chemical stability constraints must be taken into consideration. Here, we present a method to utilize the mechanical stability of a ZrO2 based electrolyte for this application. Facile low temperature synthesis of solid solution (Y2O3)(0.08)(ZrO2)(0.92)-(Gd2O3)(0.1)(CeO2)(0.9) free standing electrolytes by co-sputtering is demonstrated. Fuel cells integrating these nanoscale electrolytes show power output of over 1000 mW cm(-2) at 510 degrees C and are thermomechanically robust. The results demonstrate a general route for low temperature synthesis of nanoscale functional oxide alloys for thin film solid oxide fuel cells. (C) 2011 Elsevier B.V All rights reserved.