Rapid multiple property determination from bulk materials libraries prepared from chemically synthesized powders

A variety of high-performance materials are utilized in electrical, electronic, and mechanical systems. Such systems account for a significant fraction of the world’s electricity consumption. The next generation of such systems urgently require new material compositions which possess a better combination of both structural and functional properties. Only accelerated methodologies can rapidly determine the required multiple property set. Hence, a range of iron–cobalt–nickel ternary alloy composition powders were chemically synthesized. Compositionally graded bulk materials libraries were prepared by spark plasma sintering of these powders. A multiple property set of the crystal structure, magnetic, mechanical, and electrical properties were determined for a range of compositions. This property set revealed that a good combination of magnetic and mechanical properties can be obtained from Fe₅₀Co₄₀Ni₁₀, high electrical resistivity from Fe₅₄Co₁₇Ni₂₉ and high saturation magnetization as well as high hardness from Fe₅₇Co₂₉Ni₁₄. Thus, this multiple property library, developed by accelerated methodologies, can be utilized to identify new ternary compositions satisfying diverse property sets relevant to next generation systems.

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.