We present methodologies for the efficient integration of multiple mixed gas fuel cells. Clear evidences for a significant potential loss in the conventional integration of co-planar multi-cells were observed. Experimental and computational analyses were used to confirm the existence of ionic current leakage and determine the design criteria in this configuration. Various designs for the suppression of ionic current leakage such as full-isolation and surface compartment of electrolyte were also examined for the efficient fabrication of mixed gas fuel cells. (C) 2009 Elsevier B.V. All rights reserved.