Thermoregulated polyoxometalate-based ionic-liquid gel electrolytes

A series of vanadium-substitutive polyoxometalate-based ionic liquids, [PyPS](6)PW9V3O40, [PyPS](4)PW11VO40, [PyPS](4)PMo11VO40 and [PyPS](7)P2W17VO62, bearing sulfo-group grafted ammonium (PyPS), are transformed to reversible thermal-response gel-type compounds. Interestingly, these geltype compounds exhibit an obvious increase in their conductivity during the reversible phase transformation, which means that they are a novel series of reversible thermal-response gelation electrolytes. The relationship between the component elements of the polyoxometalate-based ionic liquids and their electrochemical performances has been studied. The Dawson-type compound ([PyPS](7)P2W17VO62) has a higher conductivity than the Keggin-type one ([PyPS](4)PW11VO40) with the same number of vanadium atoms in the structure. What's more, the W-containing compounds ([PyPS](6)PW9V3O40 and [PyPS](4)PW11VO40) have higher conductivities than the Mo-containing one ([PyPS](4)PW11VO40).