Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H<sub>2</sub>/O<sub>2</sub> fuel cells

Liu, Lei; Chu, Xiaomeng; Liao, Jiayou; Huang, Yingda; Liu, Ying; Ge, Ziyi; Hickner, Michael A.; Li, Nanwen

doi:10.1039/c7ee02468a

Cited by 236 publications

(143 citation statements)

References 45 publications

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“…Recent studies have shown that cyclic ammonium (24)(25)(26)(27) and tetraalkyl ammonium cations, specifically those with long alkyl chains (18)(19)(20)(28)(29)(30), have better alkaline stability than traditional benzyltrimethyl ammonium cations (31)(32)(33). Other cations, such as imidazolium (16,21,(34)(35)(36)(37)(38)(39)(40)(41)(42)(43), phosphonium (44)(45)(46)(47)(48)(49), and metal cations (50)(51)(52)(53)(54), have also been widely applied in various AAEMs.…”

Section: Significancementioning

confidence: 99%

Highly conductive and chemically stable alkaline anion exchange membranes via ROMP of trans -cyclooctene derivatives

You

Padgett

MacMillan

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

129

107

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Alkaline anion exchange membranes (AAEMs) are an important component of alkaline exchange membrane fuel cells (AEMFCs), which facilitate the efficient conversion of fuels to electricity using nonplatinum electrode catalysts. However, low hydroxide conductivity and poor long-term alkaline stability of AAEMs are the major limitations for the widespread application of AEMFCs. In this paper, we report the synthesis of highly conductive and chemically stable AAEMs from the living polymerization of trans-cyclooctenes. A trans-cyclooctene-fused imidazolium monomer was designed and synthesized on gram scale. Using these highly ring-strained monomers, we produced a range of block and random copolymers. Surprisingly, AAEMs made from the random copolymer exhibited much higher conductivities than their block copolymer analogs. Investigation by transmission electron microscopy showed that the block copolymers had a disordered microphase segregation which likely impeded ion conduction. A cross-linked random copolymer demonstrated a high level of hydroxide conductivity (134 mS/cm at 80°C). More importantly, the membranes exhibited excellent chemical stability due to the incorporation of highly alkaline-stable multisubstituted imidazolium cations. No chemical degradation was detected by 1 H NMR spectroscopy when the polymers were treated with 2 M KOH in CD 3 OH at 80°C for 30 d.alkaline anion exchange membrane | trans-cyclooctene | block and random copolymer | cross-linked polymer | transmission electron microscopy A lkaline anion exchange membranes (AAEMs) are a class of polymer electrolytes constructed from immobilized cations with hydroxide counteranions (1-3). AAEMs have been widely used for a variety of electrochemical applications, such as redox flow batteries, electrodialysis, and water electrolysis (4-7). One of the most important applications for AAEMs is their use as polyelectrolytes in alkaline exchange membrane fuel cells (AEMFCs). These devices can efficiently convert chemical energy in fuels (e.g., H 2 , hydrazine, and direct alcohols) into electricity. In comparison with proton exchange membrane fuel cells and aqueous alkaline fuel cells, AEMFCs are advantageous because they allow for rapid reduction of oxygen at the cathode, limit fuel cross-over, prevent the formation of carbonate precipitates, and are compatible with nonnoble electrocatalysts (8-12). Because of their essential role in AEMFCs, AAEMs have been extensively studied to optimize their performance and, in particular, to improve their hydroxide conductivity and alkaline stability.Hydroxide conductivity is one of the most important parameters used to evaluate AAEMs, because it is directly related to the ohmic resistance and power density of an AEMFC (9). There are several strategies to enhance the hydroxide conductivity of AAEMs. The most straightforward method is to increase the ion exchange capacity (IEC), such that more ions are present in AAEMs. However, a higher IEC typically results in higher water uptake. While the presence of water facilitates h...

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Section: Significancementioning

confidence: 99%

Highly conductive and chemically stable alkaline anion exchange membranes via ROMP of trans -cyclooctene derivatives

You

Padgett

MacMillan

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

129

107

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“…[13][14][15][16][17][18][19][20][21][22] All ex situ studies show high performances, such as conductivities of 20-90 mS cm À1 in contact with liquid water and stabilities of up to 200 h in aqueous 1 M KOH or NaOH at 80 C. 13,[16][17][18][19][20][21][22] However, poor stability with hydration cycling, and lowered conductivity for lower relative humidity have also been reported for these types of membranes. 16,23,24 In operating AEMFCs, single polarisation curves of PPO-based membranes have shown that these materials can be used in a fuel cell. 13,17,18,[25][26][27] However, there are only a few studies where correlations between membrane properties ex situ and in the fuel cell are analysed.…”

Section: Introductionmentioning

confidence: 99%

Fuel cell evaluation of anion exchange membranes based on poly(phenylene oxide) with different cationic group placement

Carlson

Eriksson

Olsson

et al. 2020

Sustainable Energy Fuels

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“…A polarization curve for an AEMFC with a PtRu/C anode, Pt/C cathode, and the F20C9N AEM operating at 60 °C under optimized gas dew points is shown in Figure a. This AEMFC was able to achieve a peak power density of 1.01 W cm −2 at 60 °C, ranking as one of the best AEM demonstrations in terms of single cell performance . By contrast, as shown in Figure S13 of the Supporting Information, AEMFC operating with an H22C9N membrane exhibited a peak power density of only 0.14 W cm −2 at 60 °C, although it is higher than that of reported AEMFC based on poly(olefin) AEMs .…”

Section: Resultsmentioning

confidence: 98%

“…To meet current goals for AMFC operation, the cell needs to maintain more than 90% of its initial operating voltage. This is a difficult requirement, which previous report have not achieved . Currently, the longest durability testing of a H 2 –O 2 type AEMFC was reported by Wang et al using a radiation grafted high density polyethylene (HDPE) AEM, with 500 h of operation with less than 10% loss in the operating voltage at a current of 600 mA cm ‐2 .…”

Section: Resultsmentioning

confidence: 99%

High Performance Anion Exchange Membrane Fuel Cells Enabled by Fluoropoly(olefin) Membranes

Zhu

Peng

Shang

et al. 2019

Adv Funct Materials

Self Cite

137

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Although the peak power density of anion exchange membrane fuel cells (AEMFCs) has been raised from ≈0.1 to ≈1.4 W cm −2 over the last decade, a majority of AEMFCs reported in the literature have not been demonstrated to achieve consistently high performance and steady-state operation. Poly(olefin)-based AEMs with fluorine substitution on the aromatic comonomer show considerably higher dimensional stability compared to samples that do not contain fluorine. More importantly, fluorinated poly(olefin)-based AEMs exhibit high hydroxide conductivity without excessive hydration due to a new proposed mechanism where the fluorinated dipolar monomer facilitates increased hydroxide dissociation and transport. Using this new generation of AEMs, a stable, high-performance AEMFC is operated for 120 h. When the fuel cell configuration is subjected to a constant current density of 600 mA cm −2 under H 2 /O 2 flow, the cell voltage declines only 11% (from 0.75 to 0.67 V) for the first 20 h during break-in and the cell voltage loss is low (0.2 mV h −1 ) over the subsequent 100 h of cell testing. The ease of synthesis, potential for low-cost commercialization, and remarkable ex situ properties and in situ performance of fluoropoly(olefin)-based AEM renders this material a benchmark membrane for practical AEMFC applications.

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Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H₂/O₂ fuel cells

Abstract: A complete investigation of poly(2,6-dimethyl-1,4-phenylene) AEMs with different quaternary ammonium groups is provided comparing the properties and fuel cell performance.

Cited by 236 publications

References 45 publications

Highly conductive and chemically stable alkaline anion exchange membranes via ROMP of trans -cyclooctene derivatives

Highly conductive and chemically stable alkaline anion exchange membranes via ROMP of trans -cyclooctene derivatives

Fuel cell evaluation of anion exchange membranes based on poly(phenylene oxide) with different cationic group placement

High Performance Anion Exchange Membrane Fuel Cells Enabled by Fluoropoly(olefin) Membranes

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Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H2/O2 fuel cells

Abstract: A complete investigation of poly(2,6-dimethyl-1,4-phenylene) AEMs with different quaternary ammonium groups is provided comparing the properties and fuel cell performance.

Cited by 236 publications

References 45 publications

Highly conductive and chemically stable alkaline anion exchange membranes via ROMP of trans -cyclooctene derivatives

Highly conductive and chemically stable alkaline anion exchange membranes via ROMP of trans -cyclooctene derivatives

Fuel cell evaluation of anion exchange membranes based on poly(phenylene oxide) with different cationic group placement

High Performance Anion Exchange Membrane Fuel Cells Enabled by Fluoropoly(olefin) Membranes

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Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H₂/O₂ fuel cells