Simple and Effective Cross-Linking Technology for the Preparation of Cross-Linked Membranes Composed of Highly Sulfonated Poly(ether ether ketone) and Poly(arylene ether sulfone) for Fuel Cell Applications

Abstract

Cross-linking technology has been considered as one of the effective strategies for improving the physicochemical stability of proton-exchange membranes (PEMs) for fuel cell applications. However, the complicated procedure, which consists of various reagents and multiple steps to form the proton-conducting cross-linked membranes, has been known to be disadvantageous to increasing the application of the cross-linking method. In this study, we present a simple and effective cross-linking technology for the development of high-performance cross-linked PEMs without any tedious chemical processes and catalysts or additives. A series of cross-linked membranes could be prepared by a simple one-step stage of casting and heating the mixture of sulfonated poly(ether ether ketone) (SPEEK) and sulfonated poly(arylene ether sulfone) (SPAES) in dimethyl sulfoxide (DMSO) solution, where DMSO works as the solvent and the reagent at the same time without any tedious chemical reaction steps. By controlling the cross-linking density, cross-linked membranes having tunable physicochemical stabilities and mechanical properties with outstanding proton conductivity could be obtained. The fuel cell performance of the membrane electrode assembly employing the cross-linked membrane with the optimum cross-linking density and composition ratio showed a maximum power density of 0.70 W cm −2 , which was superior to that employing Nafion 212 (0.58 W cm −2 ) at 80 °C under fully humidified H 2 /air condition.

Optimal method for preparing sulfonated polyaryletherketones with high ion exchange capacity by acid‐catalyzed crosslinking for proton exchange membrane fuel cells

“…Interestingly, the weight loss of membrane crosslinked with 3 M sulfuric acid solution increased from 17 to 37%, indicating the degradation of the polymer in 3 M sulfuric acid at 100°C. This can be attributed to the hydrolysis of the ether groups on polymer chain at high acid concentration 30–38 …”

“…Two commonly used crosslinking methods have been proposed. One involves the preparation of a crosslinkable polymer with sulfonic groups, while the other involves the introduction of an additional reagent for the crosslinking of the membranes 22–32 . However, both methods sacrifice the IEC values and proton conductivity of the membranes.…”

Preparation and performance of sulfonated poly(ether ether ketone) membranes enhanced with ammonium ionic liquid and graphene oxide

“…Degree of sulfonation ðDSÞ ¼ n × 100 (2) where n is the number of H E per repeat unit, AH E is the date under the graph for H E region, and P AH ðA,A',B,B',C,DÞ is the total areas under the graph for all of other aromatic hydrogen regions.…”

“…PEMFCs are considered to be one of the most promising energy conversion devices to replace the traditional internal combustion engines because of many advantages, such as eco-friendliness, non-polluting products, and high energy conversion efficiency. 1,2 The proton exchange membrane (PEM) is the key performance-defining component of PEMFCs and has been the focus of intense research by researchers. 3,4 At present, most PEMs are based on perfluorosulfonic acid (PFSA), which is composed of an electrically neutral unit and an ionized unit covalently bonded to the main chain of a hydrophobic polymer as a pendant group.…”

Self-Humidifying Membrane for High-Performance Fuel Cells Operating at Harsh Conditions: Heterojunction of Proton and Anion Exchange Membranes Composed of Acceptor-Doped SnP2O7 Composites

“…However, commercially available perfluorosulfonic acid membranes (PFSAs), such as Nafion (Dupont Chemical, Wilgminton, DE, USA) and Aciplex (Asahi Chemical Inc., Osaka, Japan), cannot function as polymer electrolyte membranes under such harsh operating conditions because the absorbed water molecules facilitating the ion transportation are evaporated, leading to a significant decrease in the membrane conductivity [6]. To date, several promising membranes based on hydrocarbon polymers have been reported, such as polyether ether ketone (PEEK) [7], poly(arylene ether sulfone) (PAES) [8,9], polysulfone (PSf) [10], and polybenzimidazole (PBI) [11,12]. Among these membranes, the H 3 PO 4 -doped PBI membrane exhibits conductivities of ca.…”