A poly(R1R2R3)–N/H3PO4 composite membrane for phosphoric acid polymer electrolyte membrane fuel cells

A poly(R₁R₂R₃)–N⁺/H₃PO₄ composite membrane has been developed for use in a polymer electrolyte fuel cell (PEMFC). The quaternized polysulfone (QNPSU) membrane doped with H₃PO₄ showed high proton conductivity (0.12 S cm⁻¹) at 160 °C and gave good performance in a single fuel cell tests. The peak power density with the QNPSU/H₃PO₄ composite membrane (at 150 °C, with dry H₂/O₂) was greater than 0.7 W cm⁻². The effect of the phosphoric acid doping level on fuel cell performances with the QNPSU membrane was investigated. The data show that the QNPSU/H₃PO₄ composite membrane is promising for higher temperature PEMFC applications. The study demonstrated that the poly(R₁R₂R₃)–N⁺/H₃PO₄ composite system produced an effective method to connect phosphoric acid to a non-conducting polymer structure, to produce a promising membrane for phosphoric acid polymer electrolyte membrane fuel cells.