Synthesis and Characterization of H₃PO₄Doped Poly(benzimidazole-co-benzoxazole) Membranes for High Temperature Polymer Electrolyte Fuel Cells

Abstract

Poly(benzimidazole-co-benzoxazole)s (PBI-co-PBO) are synthesized by polycondensation reaction with 3,3'-diaminobenzidine, terephthalic acid and 3,3'-dihydroxybenzidine or 4,6-diaminoresorcinol in polyphosphoric acid (PPA). All polymer membranes are prepared by the direct casting method (in-situ fabrication). The introduction of benzoxazole units (BO units) into a polymer backbone lowers the basic property and H 3 PO 4 doping level of the copolymer membranes, resulting in the improvement of mechanical strength. The proton conductivity of H 3 PO 4 doped PBI-co-PBO membranes decrease as a result of adding amounts of BO units. The maximum tensile strength reaches 4.1 MPa with a 10% molar ratio of BO units in the copolymer. As a result, the H 3 PO 4 doped PBI-co-PBO membranes could be utilized as alternative proton exchange membranes in high temperature polymer electrolyte fuel cells.

Tuning the oxygen reduction activity of the Pt–Ni nanoparticles upon specific anion adsorption by varying heat treatment atmospheres

“…The phosphoric acid doped polybenzimidazole (p-PBI) polymer was synthesized by reacting 3,3-diaminobenzidine (Aldrich, 99%) and terephthalic acid (Aldrich, 98%) in polyphosphoric acid (PA) solution, and the p-PBI membrane was prepared by casting the polymer solution on glass substrates at 200 1C with a doctor blade (gap size: 400 mm). [28][29][30] The single-cell test was carried out at a cell temperature of 160 1C by using a PEMFC test station (CNL Energy Co.). Hydrogen (52 mL min À1 ) and oxygen (192 mL min À1 ) were supplied to the anodes and cathodes, respectively, without humidification.…”

Studies on Ionic Conduction in Ce0.95Eu0.05P2O7at Intermediate Temperatures

“…[1][2][3][4] For operation at intermediate temperature, two routes have been adopted. One is to develop the electrolyte membrane.…”