Peroxide induced tin oxide coating of graphene oxide at room temperature and its application for lithium ion batteries.

We describe a new, simple and low-temperature method for ultra-thin coating of graphene oxide (GO) by peroxostannate, tin oxide or a mixture of tin and tin oxide crystallites by different treatments. The technique is environmentally friendly and does not require complicated infrastructure, an autoclave or a microwave. The supported peroxostannate phase is partially converted after drying to crystalline tin oxide with average, 2.5 nm cassiterite crystals. Mild heat treatment yielded full coverage of the reduced graphene oxide by crystalline tin oxide. Extensive heat treatment in vacuum at >500 °C yielded a mixture of elemental tin and cassiterite tin oxide nanoparticles supported on reduced graphene oxide (rGO). The usefulness of the new approach was demonstrated by the preparation of two types of lithium ion anodes: tin oxide-rGO and a mixture of tin oxide and tin coated rGO composites (SnO(2)-Sn-rGO). The electrodes exhibited stable charge/discharge cyclability and high charging capacity due to the intimate contact between the conductive graphene and the very small tin oxide crystallites. The charging/discharging capacity of the anodes exceeded the theoretical capacity predicted based on tin lithiation. The tin oxide coated rGO exhibited higher charging capacity but somewhat lower stability upon extended charge/discharge cycling compared to SnO(2)-Sn-rGO.

Sol-gel-derived composite antimony-doped, tin oxide-coated clay-silicate semitransparent and conductive electrodes.

A new form of conductive and transparent porous composite electrode is introduced. The electrode material is composed of antimony-doped, tin oxide (ATO)-coated mica platelets imbedded in sol-gel-derived silicate or methyl silicate network. The platelet clays self-align in a layered structure within the silicate film, an anisotropic construction that minimizes the ATO loading required to achieve electric percolation. Transparency and resistance as a function of clay loading is reported with typical values of 100 k Omega/square and 1.5 OD for a 20-microm-thick film. The transparency is lower as compared to sputtered ATO glasses, but this is, as far as we know, the best method for the low-temperature preparation of transparent, porous, and electrically conductive (as opposed to the amply reported ionically conductive) electrode materials. Permselectivity induced by the silicate and clay ingredients is demonstrated by permeation of positively charged methyl viologen compared to negatively charged ferricyanide. Prussian blue-modified ATO-coated platelets dispersed in sol-gel-derived silicate were used to demonstrate feasibility of a transparent and electrically conductive porous electrochromic material.