Proton-conductive membranes based on vanadium substituted heteropoly acids with Keggin structure and polymers

摘要

In this article, novel proton-conducting composite membranes SPEEK/PW11V and PVA/SiW11V were synthesized from vanadium substituted heteropoly acids (H(4)PW(11)VO(40)8H(2)O and H(5)SiW(11)VO(40)15H(2)O, abbreviated as PW11V and SiW11V) and polymers (SPEEK or PVA) at the weight ratio 70 : 30. The membranes were characterized by the infrared spectroscopy, X-ray powder diffraction, and scanning electron microscopy, which confirmed the maintenance of the Keggin framework and dispersion homogeneously in the polymer matrix without long-range ordering. Their proton-conducting properties were investigated with electrochemical impedance spectroscopy. The results show that the respective proton conductivities of SPEEK/PW11V and PVA/SiW11V membranes were in the order of 10(-2) and 10(-4) S cm(-1) at ambient temperature. The temperature dependence of the two composite membrane electrolytes exhibit Arrhenius behavior, and the observed activation energies to be 15.82 kJ mol(-1) for SPEEK/PW11V and 14.40 kJ mol(-1) for PVA/SiW11V, which indicates that the proton conduction complies with the Grotthuss mechanism. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42204.