Thermoresponsive Polyoxometalate/Ionic Liquid Supramolecular Gel Electrolytes for Supercapacitors: Fabrication, Structure, and Heteropolyanion Structure Effect

We report the fabrication, structure, and heteropolyanion structure effect of polyoxometalate (POM)/ionic liquid (IL) supramolecular gels. These supramolecular gels exhibit ordered structures, as a result of their excellent reversible self-assembly, and they show various physicochemical properties, determined by the heteropolyanion structure effect of POM anions. Specifically, the formation of POM/IL supramolecular gels results in a highly ordered layer-shape structure, which has been calculated using X-ray powder diffraction patterns and proven by transmission electron microscopy images for the first time. When these POM/IL supramolecular gels are heated, they become viscous liquid sols, with melting isotropic drops and even flowerlike structures on microscopic scales, while it undergoes a reversible gel–sol phase transformation from gel to sol. The heteropolyanion structure effect in these two IL gels, [TBTP]5PW10V2O40 and [TBTP]8P2W16V2O62, on their physicochemical properties is demonstrated. The POM s...