Composite proton conductive membranes composed of sulfonated poly(ether ether ketone) and phosphotungstic acid-loaded imidazole microcapsules as acid reservoirs

摘要: Abstract Imidazole microcapsules loaded with phosphotungstic acid (IMCs–HPW) were prepared and incorporated into the sulfonated polyether ether ketone (SPEEK) matrix to fabricate composite proton conductive membranes for potential use in direct methanol fuel cells. The hollow imidazole (IMCs) via distillation–precipitation polymerization, immersed HPW solution obtain which subsequently embedded membrane as acid-reservoirs. Fourier transform infrared spectroscopy concentration-absorption UV–vis spectrum of IMCs–HPW revealed tight immobilization IMCs. introduction greatly enhanced thermal stability as-prepared SPEEK/IMCs–HPW exhibited reduced swelling degree, crossover particular dramatically conductivity. maximum conductivity at room temperature was 0.0316 S cm −1 a doping content 15 wt%, nearly three times higher than that pristine SPEEK membrane. Incorporation reservoirs not only rendered improved water-retention property but also provided additional proton-transfer pathways, leading superior conduction even under 20% relative humidity two orders magnitude over pure membranes.