Silane cross-linked proton electrolyte membranes based on branched sulphonated poly(ether ether ketone)s with high sulphonation degree for direct methanol fuel cells

Abstract

In this study, the silane cross-linked membranes based on branched sulphonated poly(ether ether ketone)s (BSPEEK) with a high sulphonation degree of 1.2 have been successfully prepared for direct methanol fuel cells. 3-Mercaptopropyltrimethoxysilane (MPTMS) was grafted onto the BSPEEK backbone via the thiol-ene click reaction between propenyl and thiol groups. The expected silane cross-linked structure within the membrane was confirmed by Fourier transform infrared spectroscopy and solubility test. The silane cross-linked membranes displayed excellent chemical stability and improved mechanical property. Furthermore, the water uptake and methanol permeability of the membranes decreased with the increasing proportion of MPTMS. The dense membrane structure formed by Si-O-Si cross-linking made a great contribution to the improvement of the membrane's properties. Therefore, the as-prepared membranes may be potential proton electrolyte membrane for fuel cells.

Chemically stable thioether cross-linked membranes derived from sulfonated poly(arylene ether ketone)s for direct methanol fuel cells

“…3,4 Unfortunately, the severe fuel diffusion across the proton electrolyte membrane (PEM) has strongly hindered large-scale applications of DMFCs. [5][6][7] The permeated methanol from the anode to the cathode is detrimental to overall fuel cell performance because it diminishes fuel efficiency and poisons the cathode catalyst, which leads to a remarkable energy loss of DMFC with a reduced cell voltage.…”

Organic–inorganic hybrid proton-conducting electrolyte membranes based on sulfonated poly(arylene ether sulfone) and SiO2–SO3H network for fuel cells

“…[19][20][21] One way to avoid the problem by cross-linking method is to use a cross-linker that contains the proton conducting moiety such as sulfonic acid-functionalized silica (SiO 2 -S). [22][23][24] But directly doping with acid-functionalized filler usually causes hybrid membrane instability mainly because the poor molecular interactions easily cause aggregation of the fillers in the organic matrix. 25 Sol-gel method is an effective approach to introduce hygroscopic inorganic components and crosslinking structure.…”