Trifluoromethanesulfonimide-based hygroscopic semi-interpenetrating polymer network for enhanced proton conductivity of nafion-based proton exchange membranes at low humidity

Abstract

In this study, a super acid with impressive hygroscopicity, 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethanesulfonyl)imide (MPTI), is exploited to improve the proton conductivity of PEMs at low humidity. Importantly, MPTI can deliquesce into an aqueous solution by capturing moisture from air at a considerable rate. Investigation of the hygroscopicity of MPTI and the corresponding mechanism by molecular dynamics simulation show a total interaction energy between MPTI and water of-368.13 kJ mol-1 , which greatly exceeds those of model derivatives with other typical hygroscopic groups. To apply MPTI in PEMs and prevent leakage, MPTI is incorporated into a semi-interpenetrating polymer network via in situ polymerization, and Nafionbased composite membranes are fabricated. The water uptake of the obtained hybrid membranes is substantially increased by up to 66.61% at 40% RH and 90.04% at 95% RH. This optimization of the water environment facilitates the dissociation of protons and the formation of hydrogen bond networks for high-speed proton conduction. As a result, the proton conductivity of the membranes increases by up to two orders of magnitude at low humidity. Notably, this composite membrane enhanced the performance of a single fuel cell at 60% RH by 41.9%.

Phase Transformation Dynamics in Sulfate-Loaded Lanthanide Triphosphonates. Proton Conductivity and Application as Fillers in PEMFCs

“…The power and current density values obtained for these composite membranes are higher than those obtained for pristine Nafion ( Table 4 ) and, to the best of our knowledge, represent the highest values reported for composite Nafion/MOF membranes. 68 − 70 …”

SPEEK and SPPO Blended Membranes for Proton Exchange Membrane Fuel Cells

“…Fuel cells (FCs) serve to convert fuels into electric power in an efficient and environmentally friendly manner. Proton exchange membrane fuel cells (PEMFCs) are compact, lightweight with high current densities and hence are advantageous over other fuel cells [ 1 , 2 , 3 ]. Compared to other sources of energy, PEM fuel cells have many advantages.…”

Nafion-Based Proton-Exchange Membranes Built on Cross-Linked Semi-Interpenetrating Polymer Networks between Poly(acrylic acid) and Poly(vinyl alcohol)

“…Semi-IPN membranes made of Nafion as a penetrant have also been investigated as a fuel cell mainly for direct methanol fuel cells by blending Nafion with cross-linked engineering polymers such as sPAEK, sPES, PBI, and functionalized PI . These composite membranes showed significantly enhanced mechanical/dimensional stabilities and used reduced methanol as a fuel.…”