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High-performance imidazole-containing polymers for applications in high temperature polymer electrolyte membrane fuel cells

Mu, Tong ; Wang, Lele ; Wang, Qian ; Wu, Yang ; Jannasch, Patric LU orcid and Yang, Jingshuai (2024) In Journal of Energy Chemistry 98. p.512-523
Abstract

This work focuses on the development of high temperature polymer electrolyte membranes (HT-PEMs) as key materials for HT-PEM fuel cells (HT-PEMFCs). Recognizing the challenges associated with the phosphoric acid (PA) doped polybenzimidazole (PBI) membranes, including the use of carcinogenic monomers and complex synthesis procedures, this study aims to develop more cost-effective, readily synthesized and high-performance alternatives. A series of superacid-catalyzed polyhydroxyalkylation reactions have been meticulously designed between p-triphenyl and aldehydes bearing imidazole moieties, resulting in a new class of HT-PEMs. It is found that the chemical structure of... (More)

This work focuses on the development of high temperature polymer electrolyte membranes (HT-PEMs) as key materials for HT-PEM fuel cells (HT-PEMFCs). Recognizing the challenges associated with the phosphoric acid (PA) doped polybenzimidazole (PBI) membranes, including the use of carcinogenic monomers and complex synthesis procedures, this study aims to develop more cost-effective, readily synthesized and high-performance alternatives. A series of superacid-catalyzed polyhydroxyalkylation reactions have been meticulously designed between p-triphenyl and aldehydes bearing imidazole moieties, resulting in a new class of HT-PEMs. It is found that the chemical structure of aldehyde-substituted N-heterocycles significantly impacts the polymerization reaction. Specifically, the use of 1-methyl-2-imidazole-formaldehyde and 1H-imidazole-4-formaldehyde monomers leads to yield high-viscosity, rigid and ether-free polymers, denoted as PTIm-a and PTIm-b. Membranes fabricated from these polymers, due to their pendent imidazole groups, exhibit an exceptional capacity for PA absorption. Notably, PTIm-a, featuring methylimidazole moieties, demonstrates a superior chemical stability which maintains morphology and structural stability during 350 h of Fenton testing. After being immersed in 75 wt% PA at 40 °C, the PTIm-a membrane achieves a PA content of 152%, maintains a good tensile strength of 13.6 MPa, and exhibits a moderate conductivity of 50.2 mS cm-1 at 180 °C. Under H2/O2 operational conditions, a single cell based on the PTIm-a membrane attains a peak power density of 732 mW cm-2 at 180 °C without backpressure. Furthermore, the membrane demonstrates stable cycle stability over 173 h within 18 days period at a current density of 200 mA cm-2, indicating its potential for practical application in HT-PEMFCs. This work contributes innovative strategies for the synthesis of advanced HT-PEMs, offering significant improvements in membrane properties and fuel cell performance, thus expanding the horizons of HT-PEMFC technology.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Energy Chemistry
volume
98
pages
12 pages
publisher
Elsevier
external identifiers
  • scopus:85199485119
ISSN
2095-4956
DOI
10.1016/j.jechem.2024.07.017
language
English
LU publication?
yes
id
0a4d8976-434e-4c48-bf6e-f91db7dcac4a
date added to LUP
2024-01-24 10:50:31
date last changed
2024-09-05 04:03:33
@article{0a4d8976-434e-4c48-bf6e-f91db7dcac4a,
  abstract     = {{<p style="font-family: &quot;Times New Roman&quot;; font-size: medium;">This work focuses on the development of high temperature polymer electrolyte membranes (HT-PEMs) as key materials for HT-PEM fuel cells (HT-PEMFCs). Recognizing the challenges associated with the phosphoric acid (PA) doped polybenzimidazole (PBI) membranes, including the use of carcinogenic monomers and complex synthesis procedures, this study aims to develop more cost-effective, readily synthesized and high-performance alternatives. A series of superacid-catalyzed polyhydroxyalkylation reactions have been meticulously designed between p-triphenyl and aldehydes bearing imidazole moieties, resulting in a new class of HT-PEMs. It is found that the chemical structure of aldehyde-substituted N-heterocycles significantly impacts the polymerization reaction. Specifically, the use of 1-methyl-2-imidazole-formaldehyde and 1H-imidazole-4-formaldehyde monomers leads to yield high-viscosity, rigid and ether-free polymers, denoted as PTIm-a and PTIm-b. Membranes fabricated from these polymers, due to their pendent imidazole groups, exhibit an exceptional capacity for PA absorption. Notably, PTIm-a, featuring methylimidazole moieties, demonstrates a superior chemical stability which maintains morphology and structural stability during 350 h of Fenton testing. After being immersed in 75 wt% PA at 40 °C, the PTIm-a membrane achieves a PA content of 152%, maintains a good tensile strength of 13.6 MPa, and exhibits a moderate conductivity of 50.2 mS cm<sup>-1</sup> at 180 °C. Under H<sub>2</sub>/O<sub>2</sub> operational conditions, a single cell based on the PTIm-a membrane attains a peak power density of 732 mW cm<sup>-2</sup> at 180 °C without backpressure. Furthermore, the membrane demonstrates stable cycle stability over 173 h within 18 days period at a current density of 200 mA cm<sup>-2</sup>, indicating its potential for practical application in HT-PEMFCs. This work contributes innovative strategies for the synthesis of advanced HT-PEMs, offering significant improvements in membrane properties and fuel cell performance, thus expanding the horizons of HT-PEMFC technology.</p>}},
  author       = {{Mu, Tong and Wang, Lele and Wang, Qian and Wu, Yang and Jannasch, Patric and Yang, Jingshuai}},
  issn         = {{2095-4956}},
  language     = {{eng}},
  pages        = {{512--523}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Energy Chemistry}},
  title        = {{High-performance imidazole-containing polymers for applications in high temperature polymer electrolyte membrane fuel cells}},
  url          = {{http://dx.doi.org/10.1016/j.jechem.2024.07.017}},
  doi          = {{10.1016/j.jechem.2024.07.017}},
  volume       = {{98}},
  year         = {{2024}},
}