High performance nitrile copolymers for polymer electrolyte membrane fuel cells

Abstract

a b s t r a c tThis paper reports the fuel cells (DMFC and PEMFC) performance using sulfonated poly(arylene ether ether nitrile) (SPAEEN) copolymers containing sulfonic acid group arranged in structurally different ways. The membrane electrode assembly (MEA) fabricated from SPAEEN containing 60 mol% of angled naphthalenesulfonic acid group (m-SPAEEN-60) had superior performance over those derived from pendent naphthalenesulfonic acid group (p-SPAEEN) or sulfonated hydroquinone (HQ-SPAEEN) in H 2 /air and/or DMFC conditions. For example, the current density of the MEA using m-SPAEEN-60 at 0.5 V and 2.0 M methanol was 250 mA/cm 2 , whereas the current densities of the MEAs using p-SPAEEN-50 and HQ-SPAEEN-56 were 185 and 190 mA/cm 2 , respectively. In addition, compared with the sulfonated polysulfone (BPSH-35) and Nafion membranes, the copolymer containing nitrile group showed the improved cell performance. For example, the power density of the MEA using m-SPAEEN-60 at 250 mA/cm 2 and 2.0 M methanol was 125 mW/cm 2 , whereas the power densities of the MEAs using sulfonated polysulfone (BPSH-35) and Nafion were 115 and 113 mW/cm 2 , respectively. m-SPAEEN-60 showed stable cell performance during extended operation (>100 h).

Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs)

“…Furthermore, SPAEEN with sulfonic acid groups meta to the ether linkage (m-SPAEEN) and those with sulfonic acid groups located pendant on a phenyl ring (P-SPAEEN) exhibited much higher proton conductivities because the meta linkage and the long-distance connectivity of their sulfonic acid groups, could eliminate deactivation of the sulfonic acid groups, respectively [90]. As a result, m-SPAEEN membranes showed high performance in both PEMFC and DMFC fuel cell applications [106,107]. The authors also explained the effect of the angled structure, which increased the interchain spacing and created pores with sulfonic acid groups within.…”

Copoly(arylene ether)s Containing Pendant Sulfonic Acid Groups as Proton Exchange Membranes † NRCC Publication No. 50899.

“…A highly fluorinated main-chain in the sPAE series provides a high degree of chain hydrophobicity and chemical stability to the materials. 9 In our previous study, 26 it was shown that the introduction of nitrile groups into sulfonated copolymers of specific structures reduced the water uptake (wt %) and dimensional swelling (vol %). The present sPAEN contains an unprecedented high content of phenylnitrile groups for an experimental PEM material.…”

“…We suggest that a plausible factor for the low water uptake of copolymers containing nitrile groups is the presence of strong nitrile dipole interchain interactions occurring in certain polymer structural configurations that combine to limit swelling in water. 23,26 In addition, nitrile-sulfonic acid group interactions also appear to be important, as nitrile groups have been found to associate with sulfonic acid groups through bridging water molecules in specific spectroscopic studies. Table 2 also shows the proton conductivity of the present sPAE and sPAEN PEMs and Nafion that were measured on free-standing membranes.…”

Sulfonated poly(ether sulfone)‐based catalyst binder for a proton‐exchange membrane fuel cell

“…Also, hydrocarbon-based polymer membranes have been demonstrated for fuel cell operations with a Nafion binder in the catalyst layers. [4][5][6][7][8][9][10][11][12][13][14] However, the systems containing Nafion binder exhibited poor interfacial compatibility between the membrane and electrodes. 4 Therefore, the use of hydrocarbon-based polymers as binders in the catalyst layer is emerging as a new area of research.…”