Finely controlled swelling: A shortcut to construct ion-selective channels in polymer membranes. (26th May 2021)

• Record Type: Journal Article
• Authors: Jiang, Fengjing; Zhang, Yue; Wang, Feiran; Zhou, Xinjie; Liao, Weineng
• Is Part Of: Polymer. Volume 225(2021)
• Publication Date: 2021-05-26
• Subjects: Ion selectivity -- Swelling -- Proton exchange membranes -- Vanadium redox flow batteries; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.123793
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Finely controlled swelling is reported as a universal and facile method to construct abundant ion-selective channels in polymer membranes. In this work, excellent ion-selectivity of H + /V n+ is achieved by using a swelling-solidification method based on sulfonated poly(ether sulfone) (SPES) with only 20% sulfonation degree. The swelling degree of the membranes is well controlled by adjusting the solvent ratio of the swelling agent and the swelling time to achieve desired proton conductivity and V n + permeability. The as-prepared membrane is successfully applied as highly selective separator for vanadium redox flow batteries (VRFBs). Key properties such as morphology, proton conductivity, vanadium permeability, ion selectivity, tensile strength and durability are comprehensively characterized and studied. Besides, the performance of the single cells assembled with the swollen SPES membranes are tested and compared with the commercial Nafion®212 membrane. The results indicate that, the VRFB single cell with the swollen SPES membrane shows high energy efficiency exceeding 83% at 100 mA cm −2 and excellent cycling stability over 290 charge-discharge cycles. The capacity retention of the cell with the SPES membrane even reaches 98.21% after 100 cycles at 100 mA cm −2, 24.06% higher than that of Nafion®212 membrane. Graphical abstract: Image 1 Highlights: Ion-selective membrane is prepared via finely controlled swelling method. Proton conductivity and ion selectivity of the membrane can be precisely adjusted. The energy efficiency of the cell reaches as high as 83% at 100 mA cm −2 . Capacity retention of 98.21% after 100 charge-discharge cycles is achieved. The membrane possesses excellent cycling stability in VRFBs.