Novel pore-filling membrane based on block sulfonated poly (ether sulphone) with enhanced proton conductivity and methanol resistance for direct methanol fuel cells. (1st June 2019)

• Record Type: Journal Article
• Authors: Zhang, Chongyang; Yue, Xigui; Mu, Yongfeng; Zuo, Xiaodan; Lu, Nan; Luo, Yuchao; Na, Ruiqi; Zhang, Shuling; Wang, Guibin
• Is Part Of: Electrochimica acta. Volume 307(2019)
• Page Start: 188
• Page End: 196
• Publication Date: 2019-06-01
• Subjects: Pore-filling -- Block polymer substrate -- Fuel crossover -- Polymer electrolyte membrane -- Direct methanol fuel cell; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.03.189
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: The problem remains unsolved in DMFCs applications that the increase in proton conductivity is usually caused the permeation of methanol. Herein, a novel kind of pore-filling membrane is investigated to meet this challenge. The porous substrate is fabricated from block poly (ether sulphone) with low degree of sulfonation, which form well-developed conductive channels owing to an aggregation of sulfonic acid groups, ensuring low methonal crossover and swelling ratio. The pore structures are achieved by a solution casting method which introduces alpha-cyclodextrin as the porogen. The resulting porous substrate possesses homogeneous opening pore structures. Then, the filling electrolyte, an organic-soluble tetrabutylammonium 4-vinylbenzene sulfonate, is used to fill the substrate and form a crosslinked network inside the pores to ensure high proton conductivity. The pore-filling membrane with block polymers shows higher proton conductivity (0.083 S cm −1 at 80 °C) than that prepared by random polymers (0.072 S cm −1 at 80 °C). Compared with Nafion 117, the composite membrane exhibits higher dimensional stability (6.6%) and methanol resistance (4.0 × 10 −7 cm 2 s −1 ). Furthermore, the pore-filling membrane outperforms Nafion 117 with an open circuit voltage of 0.61 V as well as a maximum power density of 46.8 mW/cm 2 under 10 M methanol condition. Graphical abstract: Image 1 Highlights: Novel CSPS filled SPES pore-filling proton exchange membrane. Porous substrate based on block sulfonated copolymers enhanced proton conductivity. Significant suppression of methanol crossover over pore-filling membranes. Single cell performance outperformed Nafion 117 in 10 M methanol.