Toward silicon anodes for next-generation lithium ion batteries: a comparative performance study of various polymer binders and silicon nanopowders.

Silicon is widely regarded as one of the most promising anode materials for lithium ion and next-generation lithium batteries because of its high theoretical specific capacity. However, major issues arise from the large volume changes during alloying with lithium. In recent years, much effort has been spent on preparing nanostructured silicon and optimizing various aspects of material processing with the goal of preserving the electrode integrity upon lithiation/delithiation.

Low-temperature formation of cubic β-PbF2: precursor-based synthesis and first-principles phase stability study.

A precursor-based approach to the cubic β-phase of PbF(2) was developed and allowed the preparation of this high-temperature phase well below the temperature for transition from the orthorhombic α- to the cubic β-phase. The formation of β-PbF(2) from the molecular precursors Pb[Se(C(6)H(2)(CF(3))(3))](2) and Pb(C(6)H(2)(CF(3))(3))(2) is facilitated by the presence of several short PbF contacts in these molecules. The cubic form of PbF(2) was obtained as macroscopic crystals as well as nanoparticulate powder.

Polymer-assisted preparation of nanoscale films of thermoelectric PbSe and PbTe and of lead chalcogenide-polymer composite films.

Polymer films of polyethyleneoxide (PEO) or poly(L-lactide) (PLLA) containing a single-source precursor for either PbSe or PbTe were used to produce films of nanoparticles of these thermoelectric materials. The monomeric homoleptic chalcogenolates lead(II) bis-(2,4,6-trifluoromethylphenylselenolate) Pb[SeC(6)H(2)(CF(3))(3)](2) and lead(II) bis-[tris(trimethylsilyl)silyl-tellurolate] Pb[TeSi(SiMe(3))(3)](2) were used as single-source precursors for the thermolytic formation of the lead chalcogenides. The thickness and the quality of as-obtained thin films depended decisively on the spin-coating conditions, on the polymer, on the precursor concentration in the composite film before thermolysis and on the annealing time.

Thin-walled Er3+:Y2O3 nanotubes showing up-converted fluorescence.

Up-converted red and green fluorescence has been measured in low-crystallinity Er3+:Y2O3 nanotubes upon IR excitation. A new preparation procedure for thin-walled erbium doped yttria nanotubes using alumina templates as shape defining tools and rare earth nitrates as precursors for a purely thermolytic production of erbium doped yttria was developed. The products with a diameter of approximately 40-50 nm and a wall thickness of only 6-8 nm showed up-converted fluorescence with green and red emission bands when excited at 815 nm.

Nanoscale zinc antimonides: synthesis and phase stability.

Highly crystalline single-phase nanoparticles of the important thermoelectric materials Zn4Sb3 and ZnSb were prepared from solvochemically activated powders of elemental zinc and elemental antimony. Low-temperature reactions with reaction temperatures of 275-300 degrees C were applied using an excess of elemental zinc. The nanoscale thermoelectrics obtained were characterized by X-ray powder diffraction, transmission electron microscopy, and thermal analysis.