Fabrication of Nanocomposite Membrane via Combined Electrospinning and Casting Technique for Direct Methanol Fuel Cell

Abstract

<span class="fontstyle0">Emergence of nanotechnology has resulted in the introduction of the electrospinning process in fabricating and characterising the polymer electrolyte membrane from the sulfonated poly (ether ether ketone) (SPEEK) nanocomposite membrane comprised of electrospun Cloisite15A</span><span class="fontstyle0" style="font-size: 4pt;">® </span><span class="fontstyle0">(e-spun CL) for direct methanol fuel cell (DMFC). Poly (ether ether ketone) polymer is sulfonated up to 63% by sulfuric acid. SPEEK63/e-spun CL nanofbers were fabricated via electrospinning in which SPEEK63 was used as carrier polymer while the SPEEK63/e-spun CL nanocomposite membrane was obtained by the casting method. Characterizations on physical, morphological and thermal properties of SPEEK63/e-spun CL were conducted and compared to the SPEEK membrane fabricated by casting simple mixing 2.5wt.% Cloisite15A</span><span class="fontstyle0" style="font-size: 4pt;">® </span><span class="fontstyle0">and 5.0wt.% triaminopyrimidine solution (SPEEK63/2.5CL/5.0TAP). Scanning electron microscopy (SEM) showed well electrospun Cloisite15A</span><span class="fontstyle0" style="font-size: 4pt;">® </span><span class="fontstyle0">with an average diameter nanofber around 187.4 nm. Moreover, feld emission scanning electron microscopy (FESEM) revealed that Cloisite15A</span><span class="fontstyle0" style="font-size: 4pt;">® </span><span class="fontstyle0">particles at a nanometer range were uniformly distributed and 66% smaller than those in SPEEK63/2.5C/5.0TAP. Furthermore, x-ray diffraction proved that the dispersion state of Cloisite15A</span><span class="fontstyle0" style="font-size: 4pt;">® </span><span class="fontstyle0">fell into an intercalated phase. A very small amount of Cloisite15A</span><span class="fontstyle0" style="font-size: 4pt;">® </span><span class="fontstyle0">(0.05wt.%) in SPEEK63/e-spun CL successfully enhanced the proton conductivity up to 50%, whereas, unfortunately the methanol permeability value was 27 times higher than SPEEK63/2.5CL/5.0TAP. Proton conductivity and methanol permeability of SPEEK63/e-spun CL were 24.49 x 10</span><span class="fontstyle0" style="font-size: 4pt;">-3 </span><span class="fontstyle0">Scm</span><span class="fontstyle0" style="font-size: 4pt;">-1 </span><span class="fontstyle0">and 3.74 x 10</span><span class="fontstyle0" style="font-size: 4pt;">-7 </span><span class="fontstyle0">cms</span><span class="fontstyle0" style="font-size: 4pt;">-1</span><span class="fontstyle0">, respectively. Even though this study contributed to 95% selectivity lower than SPEEK63/2.5CL/5.0TAP, electrospinning showed a promising technique to further reduce original sized Cloisite15A</span><span class="fontstyle0" style="font-size: 4pt;">® </span><span class="fontstyle0">particles from mixed size (μm and nm) to nanometer sized. In addition, by fne tuning, the dispersion of Cloisite15A</span><span class="fontstyle0" style="font-size: 4pt;">® </span><span class="fontstyle0">enhances the SPEEK63/e-spun CL performance in DMFC.</span>