Crown ether-based anion exchange membranes with highly efficient dual ion conducting pathways

Q Yang; L X Sun; W T Gao; Z Y Zhu; X Gao; Q G Zhang; A M Zhu; Q L Liu

doi:10.1016/j.jcis.2021.07.043

Crown ether-based anion exchange membranes with highly efficient dual ion conducting pathways

J Colloid Interface Sci. 2021 Dec 15:604:492-499. doi: 10.1016/j.jcis.2021.07.043. Epub 2021 Jul 10.

Authors

Q Yang¹, L X Sun², W T Gao², Z Y Zhu², X Gao², Q G Zhang², A M Zhu², Q L Liu³

Affiliations

¹ Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Department of Chemical & Biochemical Engineering, The College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Zhangzhou 363000, China.
² Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Department of Chemical & Biochemical Engineering, The College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
³ Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Department of Chemical & Biochemical Engineering, The College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China. Electronic address: qlliu@xmu.edu.cn.

PMID: 34274712
DOI: 10.1016/j.jcis.2021.07.043

Abstract

Anion exchange membranes (AEMs) are a crucial constituent for alkaline fuel cells. As the core component of fuel cells, the low performance AEMs restrict the development and application of the fuel cells. Herein, the trade-off between the OH^- conductivity and dimensional stability was solved by constructing AEMs with adequate OH^- conductivity and satisfactory alkali resistance using Tröger's base (TB) poly (crown ether)s (PCEs) as the main chain, the embedded quaternary ammonium (QA) and Na⁺-functionalized crown ether units as the cationic group. Crown ether is an electron donator, and can capture Na⁺ to form Na⁺-functionalized crown ether units to conveniently transfer OH^- and significantly promote the alkaline stability of the AEMs. The influence of the Na⁺-functionalized crown ether units on the performance of AEMs was studied in detail. The PCEs based AEMs show an obvious hydrophobic-hydrophilic microphase separation. These features make them ideal platforms for the OH^- conduction applications. As expected, the as-prepared PCEs-QA-100% (100% is the degree of cross-linking) AEM with an ionic exchange capacity (IEC) of 2.07 meq g^-1 has a high OH^- conductivity of 159 mS cm^-1 at 80 °C. Furthermore, the membrane electrode assemblies fabricated using the PCEs-QA-100% AEM possess a maximum power density of 291 mW cm^-2 under the current density of 500 mA cm^-2.

Keywords: Anion exchange membranes; Crown ether; Fuel cells; Tröger’s base polymers.