Two-dimensional NMR spectroscopy reveals cation-triggered backbone degradation in polysulfone-based anion exchange membranes

Proceedings of the National Academy of Sciences of the United States of America - Tập 110 Số 7 - Trang 2490-2495 - 2013
Christopher G. Arges1, Vijay Ramani2
1Center for Electrochemical Science and Engineering, Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA
2Center for Electrochemical Science and Engineering, Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL 60616

Tóm tắt

Anion exchange membranes (AEMs) find widespread applications as an electrolyte and/or electrode binder in fuel cells, electrodialysis stacks, flow and metal-air batteries, and electrolyzers. AEMs exhibit poor stability in alkaline media; their degradation is induced by the hydroxide ion, a potent nucleophile. We have used 2D NMR techniques to investigate polymer backbone stability (as opposed to cation stability) of the AEM in alkaline media. We report the mechanism behind a peculiar, often-observed phenomenon, wherein a demonstrably stable polysulfone backbone degrades rapidly in alkaline solutions upon derivatization with alkaline stable fixed cation groups. Using COSY and heteronuclear multiple quantum correlation spectroscopy (2D NMR), we unequivocally demonstrate that the added cation group triggers degradation of the polymer backbone in alkaline via quaternary carbon hydrolysis and ether hydrolysis, leading to rapid failure. This finding challenges the existing perception that having a stable cation moiety is sufficient to yield a stable AEM and emphasizes the importance of the often ignored issue of backbone stability.

Từ khóa


Tài liệu tham khảo

10.1002/fuce.200400045

10.1016/j.memsci.2011.04.043

10.1016/j.progpolymsci.2011.04.004

10.1149/2.F03102if

B Pivovar 2011 Alkaline Membrane Fuel Cell Workshop final report: Proceedings from the Alkaline Membrane Fuel Cell Workshop. Available at www1.eere.energy.gov/hydrogenandfuelcells/wkshp_alkaline_membrane.html pp 1–28. Accessed August 7 2012. (2011).

10.1016/j.ijhydene.2011.08.080

10.1073/pnas.0810041106

10.1039/c1cs15228a

10.1016/j.susc.2005.07.015

10.1016/j.electacta.2004.06.015

10.1126/science.1211934

T Sata Ion Exchange Membranes: Preparation, Characterization, Modification and Application (Royal Society of Chemistry, Cambridge, UK, 2004).

10.1038/nmat3191

10.1002/cssc.201100068

10.1021/ja908638d

10.1002/cssc.201200057

10.1016/j.jpowsour.2011.01.081

10.1021/ar200201x

10.1016/j.memsci.2012.05.006

10.1021/jp9122198

10.1021/jp7115577

10.1007/s10973-007-8930-x

10.1016/j.ssi.2004.09.044

10.1021/cm102957g

10.1021/ma202159d

10.1039/C1JM14331J

10.1021/cm2016164

10.1021/ma100260a

10.1016/j.jpowsour.2012.05.062

10.1016/j.memsci.2004.06.026

10.1016/0011-9164(90)85002-R

10.1002/cssc.201000074

10.1016/j.ijhydene.2011.12.069

10.1021/ma901538c

10.1039/c2jm14898f

10.1039/c2ee22466f

10.1016/j.polymer.2010.09.049

10.1016/S0376-7388(00)81290-9

10.1039/b208627a

YSK Kim D-S Kim A Labouriau H Jung P Zelenay Resonance-stabilized anion exchange polymer electrolytes. Available at www.hydrogen.energy.gov/pdfs/progress11/v_i_1_kim_2011.pdf pp 872–875. Accessed August 10th 2012. (2011).

10.1016/0376-7388(95)00292-8

10.1016/j.memsci.2012.08.045

10.1021/ma201864u

10.1021/jo100367z

TDW Claridge High-Resolution NMR Techniques in Organic Chemistry (Elsevier Science, 2nd Ed, Amsterdam, 2008).

Thông tin
Thông tin xuất bản

Proceedings of the National Academy of Sciences of the United States of America

Tập 110 Số 7

2490-2495

Thông tin tác giả