Poly(benzimidazole)/silica-ethyl-phosphoric acid hybrid membranes for proton exchange membrane fuel cells

Poly(benzimidazole) (PBI) is one of the excellent candidates of proton exchange membranes for high temperature (150-200 degrees C) proton exchange membrane fuel cells (PEMFCs). When applying to PEMFCs, the PBI membrane is usually doped with phosphoric acid to improve its proton conductivity and therefore PEMFC performance. In this work, we modify the PBI membranes by hybridizing PBI with diethyl phosphate ethyl-triethoxysilane (DEPE-TEOS). The self crosslink reactions of the DEPE-TEOS molecules and the inter-crosslink reactions between DEPE-TEOS and FBI imidazole -NH groups are then proceeded in the hybrid membrane, leading to the formation of crosslinked silica-ethyl phosphoric acid (SiP) nano-particles either bonding or without bonding to PBI. We show the mechanical properties, proton conductivity, and PEMFC performance of the PM membrane are improved by hybridizing it with SiP nano-particles. (C) 2011 Elsevier B.V. All rights reserved.