Recently polymers carrying heterocylic rings have been reported for alkaline fuel cells applications. The basicity in a conjugated structure enables the use of this kind of polymers like polyoxadiazoles (POD), polybenzoxazole, polybenzimidazole (PBI), polypyridine in fuel cells, since they are able to transport protons or OH− after doping with acid or base [5] and [6]. In a DBFC, POD membranes have been investigated and showed very good stability [7]. Unlike the typical anion exchange membranes, the conductivity of these heterocylic polymer membranes is mainly determined by doped alkaline solutions [8] and [9]. In this case, the conductivity is normally limited by their swelling in electrolytes. Porous membranes have received wide attention for battery application recently due to their attractive features like high chemical stability, high conductivity and low cost [10] and [11]. The main function of porous membranes is to separate fuels from protons or other ions, for DBFC, a porous membrane can be employed to separate View the MathML source, while still transport OH−. A Porous membrane could provide more free volumes to adsorb alkaline solutions to ensure its OH− conductivity, therefore, overcome the limitation of heterocylic membranes. To ensure the ion selectivity of porous membranes, the pores should be disconnected and the pore walls could provide multi-barriers for View the MathML source. To realize this idea, PBI was selected as matrix, membranes with highly symmetric sponge-like pores were firstly fabricated and investigated for DBFC application. In this design, all pores (sponge cells) are disconnected to ensure their high selectivity on View the MathML source, while, each free volume (pore) is filled with alkaline solution when soaked them in the DBFC electrolyte to provide membrane with high conductivity (Scheme 1). The physical and electrochemical properties of the prepared membranes were investigated in detail.