A facile route for the preparation of proton exchange membranes using sulfonated side chain graphite oxides and crosslinked sodium alginate for fuel cell

Abstract

Functionalized graphite oxide was prepared and subjected to sulfonation via a simple procedure in the presence of 1,4-butane sultone (BS) and sodium dodecylbenzenesulfonate (SDBS). The resulting sulfonated graphite oxides were incorporated into polystyrene sulfonicacid-co-maleic acid (PSSA-MA) crosslinked sodium alginate in different mass% to enhance the water uptake, mechanical stability and proton conductivity of the membranes. The physico-chemical changes in the resulting proton exchange membranes were investigated using Fourier transform infrared spectrometer (FT-IR), wide-angle X-ray diffractometer (WAXD), scanning electron microscope (SEM), differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA). The proton conductivity of the synthesized composite membranes was measured using a high precession impedance analyzer. Among the developed proton exchange membranes (PEMs), membranes containing 16 mass% of graphite oxide sulfonated with BS and SDBS respectively exhibited the highest proton conductivity of 0.133 and 0.145 S/cm at 80 °C. The ion exchange capacity (IEC) of these membranes was found to be 1.40 and 1.52 meq/g, respectively. The performance of the membranes was evaluated using fuel cell workstation at 80 °C. Among the membranes developed, 16 mass% of BS-GO and SDBS-GO incorporated membranes demonstrated the power density of 0.39 and 0.42 W/cm2, respectively. These properties are superior to the commercially available Nafion® 117 membrane. Thus, these proton exchange membranes developed here could be employed for fuel cell applications.