This paper presents a multi-scale simulation technique for designing a novel intermediate-temperature planar-type micro solid oxide fuel cell (mSOFC) stack system. This multi-scale technique integrates the fundamentals of molecular dynamics (MD) and computational fluid dynamics (CFD). MD simulations are carried out to determine the optimal composition of a potential electrolyte that is capable of operation in the intermediate-temperature region without sacrifice in performance. A commercial CFD package plus a self-written computational electrochemistry code are employed to design the fuel and air flow systems in a planar five-cell stack, including the preheating manifold. Different samarium-doped ceria (SDC) electrolyte compositions and operating temperatures from 673 K to 1023 K are investigated to identify the maximum ionic conductivity. The electrochemical performance simulation using an available 5-cell yittria-stablized-zirconia (YSZ) mSOFC stack shows good agreement with our experimental results. The same stack design is used to predict a novel SDC-mSOFC performance. Feasibiulity studies of this intermediate-temperature stack are presented using this multi-scale technique. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.