Facile Fabrication and Characterization of Improved Proton Conducting Sulfonated Poly(Arylene Biphenylether Sulfone) Blocks Containing Fluorinated Hydrophobic Units for Proton Exchange Membrane Fuel Cell Applications

Abstract

Sulfonated poly(arylene biphenylether sulfone)-poly(arylene ether) (SPABES-PAE) block copolymers by controlling the molar ratio of SPABES and PAE oligomers were successfully synthesized, and the performances of SPABES-PAE (1:2, 1:1, and 2:1) membranes were compared with Nafion 212. The prepared membranes including fluorinated hydrophobic units were stable against heat, nucleophile attack, and physio-chemical durability during the tests. Moreover, the polymers exhibited better solubility in a variety of solvents. The chemical structure of SPABES-PAEs was investigated by 1H nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC). The membrane of SPABES-PAEs was fabricated by the solution casting method, and the membranes were very flexible and transparent with a thickness of 70–90 μm. The morphology of the membranes was observed using atomic force microscope and the ionic domain size was proved by small angle X-ray scattering (SAXS) measurement. The incorporation of polymers including fluorinated units allowed the membranes to provide unprecedented oxidative and dimensional stabilities, as verified from the results of ex situ durability tests and water uptake capacity, respectively. By the collective efforts, we observed an enhanced water retention capacity, reasonable dimensional stability and high proton conductivity, and the peak power density of the SPABES-PAE (2:1) was 333.29 mW·cm−2 at 60 °C under 100% relative humidity (RH).

Improved Physicochemical Stability and High Ion Transportation of Poly(Arylene Ether Sulfone) Blocks Containing a Fluorinated Hydrophobic Part for Anion Exchange Membrane Applications

“…To investigate how the length of the hydrophilic oligomer and hydrophobic oligomer in the polymer affect hydroxide transfer, the hydroxide conductivity of QN-PAES membranes was measured at different temperatures under 100% RH. As shown in Figure 9a and Table 4, the hydroxide conductivity of membranes increased with increasing temperature due to the increasing activity and migration of ions through the expansion of ion channels [46,47,48]. As expected, the QN-PAES X19Y13 (154 mS cm −1 at 90 °C) containing longer hydrophilic oligomers and shorter hydrophobic oligomers showed the highest hydroxide conductivity compared to other QN-PAES membranes.…”

Effect of functionalized SiO 2 toward proton conductivity of composite membranes for PEMFC application

“…In general, water molecules absorbed on the membranes acted to transfer proton ions from the anode to the cathode . Commonly, the polymer electrolyte membranes with high IEC value may lead to excessive water uptake and swelling ratio, which can degrade fuel cell durability.…”

Study of High Performance Sulfonated Polyether Ether Ketone Composite Electrolyte Membranes

“…An additional cooling system is thus required to solve this problem. Fuel cells are electrochemical cells that consume fuels under nearly thermodynamically reversible conditions [5,6]. The energy conversion efficiencies are thus much higher.…”