Syntheses And Properties Of Proton Conductors Based On Heteropoly Salts And2-substituent Benzimidazole And Their Composites

The proton conductivity of organic-inorganic complexes based on the Keggin–type heteropolyacidsand2-substituted benzimidazole self-assembly to form has hydrogen bond network structure is a hotresearch topic. Silica gel is a kind of porous structure. It has a lot of silane alcohol-based exists in gelskeleton that can be designed excellent proton conductors which with silica gel as the main materials andappropriate proton conductors as auxiliary material. Chitosan has good film forming and containinghydroxyl groups and free amine, make its can be introduced into the complex large system. Grapheneoxide with layered structure, has been used to construct various kinds of electrical conductivity ofcomposite materials.In this paper, we successfully constructed five kinds of organic-inorganic complexes based on2-substituted benzimidazole and Keggin-type heteropolyacid, and we also tested their crystallographicstructure, spectroscopy properties, thermogravimetric analysis and proton conductivity. The complex[H3(L)2(PMo12O40)10H2O]ncrystallized in the triclinic space group Pī, L is2-(2-hydroxy-3-methoxybenzene) benzimidazole; the complexes [H3(M)2][PMo12O40]3.5H2O CH3CN CH3OH and[H3(M)2][PMo12O40]4H2O CH3CN crystallized in the monoclinic space group P21/c, M is2-(2-pyridyl)benzimidazole; the complexes [H3(W)2][PMo12O40]·7H2O·4CH3OH and [H3(W)4][PW12O40]·10H2Ocrystallized in the triclinic space group Pī, W is2-(2-hydroxybenzene) benzimidazole. Infrared spectrashowed the characteristic peaks of heteropolyanions and ligands; Thermogravimetric analyses showed thatthe weightlessness is small in the temperature range of20~100°C, and the structure did not changebelow250°C; Ac impedance test results showed that they showed good proton conductivity (10-4~10-3 s·cm-1) in the temperature range of85~100°C under relative humidity rang35-98%; X-raydiffraction analyses results showed that the structure did not changed after the electrochemical impedancemeasurement test.Second, we studied the synthesis methods and properties of composite materials based on thesecomplexes and functional materials. Infrared spectroscopy showed that the structure of complexes andfunctional materials coexist in composite materials; X-ray powder diffraction analyses showed that thepresence of functional materials without destroying the structure of complexes and the composite materialsstructure did not change after the ac impedance test; Electrochemical impedance tests showde that theirproton conductivities are better than organic-inorganic complexes.