New Organic-Inorganic Nanocomposite Materials for Energy Storage Applications

摘要

A method is described by which the disulfide dimer of 2,5-dimercapto- 1,3,4-thiadiazole (diDMcT, see Scheme 1) can be oxidatively intercalated into the layered structure of a V2O5 xerogel. This intercalation reaction produces a new organic-inorganic composite material with a layer spacing of 13.5 A, in contrast to the 11.55 A spacing for the parent V2O5 xerogel. During this oxidative intercalation, the diDMcT is polymerized to produce a polymer with thiadiazole rings linked by disulfides in the polymer main chain (PDTT, see Scheme 1). The composite material is characterized by uv-visible spectroelectrochemistry, x-ray diffraction, FTIR and electrochemistry. The electrochemical experiments comprised charging (oxidation) and discharging (reduction) of the material, with the bulk of the redox reaction occurring over a broad potential range of 0.5 V to -0.6 V versus SCE. The cyclic voltammogram of the composite material shows features that can be attributed to the DMcT-PDTT redox response. However, during or after reduction of the composite, the monomeric DMcT dithiolate appears to be expelled from the V2O5 interlayer region, leading to an evolution of the electrochemical response back to that of the original V2O5 material. Evidence is presented suggesting that the V2O5 host material facilitates the redox reactions of the thiol-disulfide redox couple while it is within the interlayer region.