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Sulfonate and Ammonium-Grafted Poly(isatin triphenyl) Membranes for the Vanadium Redox Flow Battery

Yang, Jingshuai LU ; Lv, Peiru ; Tang, Weiqin and Wang, Qian (2024) In ACS Applied Polymer Materials 6(17). p.10727-10737
Abstract

As one of the most critical components of the vanadium redox flow battery (VRFB), the ion exchange membrane directly influences the battery efficiency and cycle life. Herein, poly(isatin triphenyl) (PIT) containing a lactam structure and devoid of ether bonds is synthesized from isatin and p-terphenyl under superacid catalysis. To achieve the ion transport and investigate the impact of side chain end groups on the membrane performance, both cationic and anionic side chains are incorporated into PIT using glycidyl trimethylammonium chloride (GTA) and 1,3-propane sultone (PS) as the grafting reagents via ring-opening reactions. Thus, an anion exchange membrane (PIT-GTA) with quaternary ammonium and hydroxyl groups in the side chain and a... (More)

As one of the most critical components of the vanadium redox flow battery (VRFB), the ion exchange membrane directly influences the battery efficiency and cycle life. Herein, poly(isatin triphenyl) (PIT) containing a lactam structure and devoid of ether bonds is synthesized from isatin and p-terphenyl under superacid catalysis. To achieve the ion transport and investigate the impact of side chain end groups on the membrane performance, both cationic and anionic side chains are incorporated into PIT using glycidyl trimethylammonium chloride (GTA) and 1,3-propane sultone (PS) as the grafting reagents via ring-opening reactions. Thus, an anion exchange membrane (PIT-GTA) with quaternary ammonium and hydroxyl groups in the side chain and a cation exchange membrane (PIT-PS) with sulfonate groups in the side chain are obtained. Compared to PIT-PS and Nafion 115 membranes, the PIT-GTA membrane exhibits lower area resistance (AR, 0.22 Ω cm2) and reduced vanadium ion permeability (3.08 × 10−8 cm2 min-1), resulting in a significantly high ion selectivity value of 81.2 × 104 S min cm-3, which is approximately 270 times higher than that of Nafion 115 (0.3 × 104 S min cm-3). Additionally, the PIT-GTA membrane displays excellent chemical stability, with a mass loss of less than 10% after a 960 h test. Due to its superior restriction on vanadium ion migration, the VRFB assembled with PIT-GTA achieves a self-discharge duration of 289 h, significantly longer than that of Nafion 115 (86 h). In the current density range of 60-160 mA cm-2, the cell equipped with the PIT-GTA membrane demonstrates higher cell efficiencies compared to Nafion 115. Furthermore, the VRFB based on the PIT-GTA membrane exhibited excellent cycle stability and good discharge capacity retention over 1300 cycles of testing, indicating its enormous potential for application in the VRFB.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ether-free poly(isatin triphenyl), ion exchange membrane, ion selectivity, side-chain grafting, vanadium redox flow battery
in
ACS Applied Polymer Materials
volume
6
issue
17
pages
11 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85201917106
ISSN
2637-6105
DOI
10.1021/acsapm.4c01867
language
English
LU publication?
yes
id
25d4bad3-6031-495d-8a22-e7db9c8b5066
date added to LUP
2024-10-31 09:50:56
date last changed
2025-04-04 14:14:18
@article{25d4bad3-6031-495d-8a22-e7db9c8b5066,
  abstract     = {{<p>As one of the most critical components of the vanadium redox flow battery (VRFB), the ion exchange membrane directly influences the battery efficiency and cycle life. Herein, poly(isatin triphenyl) (PIT) containing a lactam structure and devoid of ether bonds is synthesized from isatin and p-terphenyl under superacid catalysis. To achieve the ion transport and investigate the impact of side chain end groups on the membrane performance, both cationic and anionic side chains are incorporated into PIT using glycidyl trimethylammonium chloride (GTA) and 1,3-propane sultone (PS) as the grafting reagents via ring-opening reactions. Thus, an anion exchange membrane (PIT-GTA) with quaternary ammonium and hydroxyl groups in the side chain and a cation exchange membrane (PIT-PS) with sulfonate groups in the side chain are obtained. Compared to PIT-PS and Nafion 115 membranes, the PIT-GTA membrane exhibits lower area resistance (AR, 0.22 Ω cm<sup>2</sup>) and reduced vanadium ion permeability (3.08 × 10<sup>−8</sup> cm<sup>2</sup> min<sup>-1</sup>), resulting in a significantly high ion selectivity value of 81.2 × 10<sup>4</sup> S min cm<sup>-3</sup>, which is approximately 270 times higher than that of Nafion 115 (0.3 × 10<sup>4</sup> S min cm<sup>-3</sup>). Additionally, the PIT-GTA membrane displays excellent chemical stability, with a mass loss of less than 10% after a 960 h test. Due to its superior restriction on vanadium ion migration, the VRFB assembled with PIT-GTA achieves a self-discharge duration of 289 h, significantly longer than that of Nafion 115 (86 h). In the current density range of 60-160 mA cm<sup>-2</sup>, the cell equipped with the PIT-GTA membrane demonstrates higher cell efficiencies compared to Nafion 115. Furthermore, the VRFB based on the PIT-GTA membrane exhibited excellent cycle stability and good discharge capacity retention over 1300 cycles of testing, indicating its enormous potential for application in the VRFB.</p>}},
  author       = {{Yang, Jingshuai and Lv, Peiru and Tang, Weiqin and Wang, Qian}},
  issn         = {{2637-6105}},
  keywords     = {{ether-free poly(isatin triphenyl); ion exchange membrane; ion selectivity; side-chain grafting; vanadium redox flow battery}},
  language     = {{eng}},
  number       = {{17}},
  pages        = {{10727--10737}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{ACS Applied Polymer Materials}},
  title        = {{Sulfonate and Ammonium-Grafted Poly(isatin triphenyl) Membranes for the Vanadium Redox Flow Battery}},
  url          = {{http://dx.doi.org/10.1021/acsapm.4c01867}},
  doi          = {{10.1021/acsapm.4c01867}},
  volume       = {{6}},
  year         = {{2024}},
}