2022 Fiscal Year Annual Research Report
Anion conductive polymers: new development for energy devices
| Project/Area Number |
22F22035
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| Allocation Type | Single-year Grants |
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| Research Institution | University of Yamanashi |
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Principal Investigator |
宮武 健治 山梨大学, 大学院総合研究部, 教授 (50277761)
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| Co-Investigator(Kenkyū-buntansha) |
YADAV VIKRANT 山梨大学, 総合研究部, 外国人特別研究員
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| Project Period (FY) |
2022-09-28 – 2025-03-31
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| Keywords | anion exchange membranes / fuel cells / water electrolyzers |
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| Outline of Annual Research Achievements |
In the first year, terpolymer-based anion exchange polymers were designed synthesized. Hexafluoroisopropylidene biphenylene and pendent perfluoro-containing phenylene groups were chosen as the hydrophobic components, and quaternized piperidinium containing C2 fluorenyl groups were chosen as the hydrophobic components. The polymerzation reaction and the following quaternization reaction both proceeded well to obtain high-molecular-weight terpolymers of targeted structure, which was characterized by NMR spectra. Flexible thin membranes were obtained by solution casting method. The ion exchange capacity of the membranes was controllable by simply changing the terpolymer composition. Currently, membrane properties are under investigation. The measurements include hydroxide ion conductivity and its temperature dependence, mechanical strength (stress versus strain, dynamic mechanical properties and their temperature/humidity dependence), and alkaline stability (in concentrated KOH solution at high temperature where the hydroxide ion conductivity is monitored as a measure of the decomposition of the ammonium groups.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The research has progressed as scheduled. Among a number of cyclic ammonium groups, piperidinium and imidazorium groups were chosen, in particular, the quaternized ammonium nitrogen groups were designed to be located at the terminal of the side chains for alkaline stability of the resulting membranes. With the help of theoretical calculations using density functional theory, targeted terpolymers were successfully obtained as high molecular weight. Similarly, properties analyses of the membrane including structural characterization, hydroxide ion conductivity, mechanical strength, and alkaline stability have been conducted as planned.
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| Strategy for Future Research Activity |
Menshutkin reaction will be used to synthesize cycloaliphatic diamines-based series-connected tetra-cationic cross-linkers with alkyl spacer length from propyl to decyl groups. The chemical structure of the prepared cross-linkers will be revealed by NMR studies (1H, 13C,and 2D-NMR). Alkaline stability for proposed tetra-cationic cross-linkers will be assessed by combination of alkaline solution exposure (nitrogen saturated 2 mol/L KOD at 100 oC) followed by NMR investigations and theoretical analysis by Density Functional Theory. The choice of aryl ether bond-free backbone rationally mitigates the backbone scission in alkaline environment.
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