| The rapid development of society has promoted new energy demand,and renewable clean energy is one of the future development trends.Fuel cells are receiving more and more attention because of their cleanness,high efficiency,and no pollution.Fuel cells have become a research hotspot in related fields because they can convert the chemical energy stored in hydrogen and oxygen into electrical energy to achieve clean,efficient,and pollution-free power generation.However,currently commercialized proton exchange membrane fuel cells need to carry precious metal catalysts such as platinum,so reducing production costs is an important issue for fuel cells.As a result,the rise of alkaline fuel cells has gradually become a breakthrough in solving this problem.However,compared with hydrogen ions in proton exchange membrane fuel cells,the diffusion coefficient of hydroxide ions is lower,and the transmission rate in fuel cells is also relatively low,so it is particularly important to improve the ion conductivity of anion exchange membranes.At the same time,the alkali-resistant stability and mechanical stability of anion exchange membrane fuel cells under high alkaline conditions have also become the shackles for their development.This paper reports a simple and efficient method for synthesizing cross-linked basic anion exchange membranes.By using 4-pyridinecarboxaldehyde iodide [PYBy] [I] and4-(imidazol-1-yl)benzaldehyde iodide [PVMIm][I] as the ion-conducting group,they are respectively combined with polyvinyl alcohol(PVA)It is cross-linked in situ with the stable group of 4-dimethylaminobenzaldehyde(DBA)to prepare anion exchange membranes based on basic pyridine and imidazole ionic liquids(ILs).After that,the two membranes were immersed in sodium hydroxide solution for ion exchange to obtain hydroxide exchange membranes [PYBy][OH]-DBA and [PVMIm][OH]-DBA.The molecular structure,thermal stability,mechanical stability,oxidation stability,alkali resistance stability,electrical conductivity and water content of the two anion exchange membranes were analyzed in detail by methods such as nuclear magnetic resonance hydrogen spectroscopy,field emission scanning electron microscopy,and thermogravimetric analysis.,And the effect of component effects on membrane performance.The results show that a dense and stable network structure is formed inside the two anion exchange membranes,and the resulting two cross-linked copolymer films exhibit high OH-ion conductivity(higher than 10-2 S/cm at room temperature)),under thecondition that the mass ratio of the stable group(PVA-DBA)remains unchanged,its ionic conductivity increases with the increase of the content of ionic liquid in the membrane,and reaches when the mass ratio of PVA to ionic liquid is 1:0.6 The highest value,which then decreases with increasing ionic liquid content.Both prepared exchange membranes have good chemical stability and mechanical properties.4-(imidazol-1-yl)benzaldehyde imidazole salt is a more stable conductive group than 4-pyridinecarbaldehyde,so[PVMIm][OH]-DBA has better performance than [PYBy][OH]-DBA The thermal stability,mechanical stability,oxidation stability and alkali resistance stability,but the conductivity is low.Both anion exchange membranes are based on polyvinyl alcohol,so they have a certain degree of biodegradability,combined with the role of supramolecules,which greatly simplifies the preparation process of AEMs.At the same time,the entire experimental process is synthesized in water phase,which is clean and environmentally friendly.Has satisfactory ion conductivity. |
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