Reversible superdense ordering of lithium between two graphene sheets.

Many carbon allotropes can act as host materials for reversible lithium uptake, thereby laying the foundations for existing and future electrochemical energy storage. However, insight into how lithium is arranged within these hosts is difficult to obtain from a working system. For example, the use of in situ transmission electron microscopy to probe light elements (especially lithium) is severely hampered by their low scattering cross-section for impinging electrons and their susceptibility to knock-on damage.

The effects of n-type doping on lithium storage in TiO2.

In this report, we discuss the Li-storage performance of niobium-doped TiO2 nanostructures (Ti(1-y)Nb(y)O(2+δ)), with a special focus on the effects of ionic/electronic charge carrier concentration (defect chemistry) on Li storage and transport properties. By Nb-doping, Li storage kinetics of titania electrode material is significantly improved mainly due to the increased electronic charge carrier concentration (n-type doping). However, it was found that there is a maximum beyond which further doping is rather detrimental to Li diffusion kinetics.

"Job-Sharing" Storage of Hydrogen in Ru/Li₂O Nanocomposites.

A "job-sharing" hydrogen storage mechanism is proposed and experimentally investigated in Ru/Li2O nanocomposites in which H(+) is accommodated on the Li2O side, while H(-) or e(-) is stored on the side of Ru. Thermal desorption-mass spectroscopy results show that after loading with D2, Ru/Li2O exhibits an extra desorption peak, which is in contrast to Ru nanoparticles or ball-milled Li2O alone, indicating a synergistic hydrogen storage effect due to the presence of both phases. By varying the ratio of the two phases, it is shown that the effect increases monotonically with the area of the heterojunctions, indicating interface related hydrogen storage.

Phase evolution in single-crystalline LiFePO₄ followed by in situ scanning X-ray microscopy of a micrometre-sized battery.

LiFePO₄ is one of the most frequently studied positive electrode materials for lithium-ion batteries during the last years. Nevertheless, there is still an extensive debate on the mechanism of phase transformation. On the one hand this is due to the small energetic differences involved and hence the great sensitivity with respect to parameters such as size and morphology.

Charge carrier accumulation in lithium fluoride thin films due to Li-ion absorption by titania (100) subsurface.

The thermodynamically required redistribution of ions at given interfaces is being paid increased attention. The present investigation of the contact LiF/TiO(2) offers a highly worthwhile example, as the redistribution processes can be predicted and verified. It consists in Li ion transfer from LiF into the space charge zones of TiO(2).

A chemically driven insulator-metal transition in non-stoichiometric and amorphous gallium oxide.

Insulator-metal transitions are well known in transition-metal oxides, but inducing an insulator-metal transition in the oxide of a main group element is a major challenge. Here, we report the observation of an insulator-metal transition, with a conductivity jump of seven orders of magnitude, in highly non-stoichiometric, amorphous gallium oxide of approximate composition GaO(1.2) at a temperature around 670 K.

Heterogeneously catalysed partial oxidation of acrolein to acrylic acid--structure, function and dynamics of the V-Mo-W mixed oxides.

The major objective of this research project was to reach a microscopic understanding of the structure, function and dynamics of V-Mo-(W) mixed oxides for the partial oxidation of acrolein to acrylic acid. Different model catalysts (from binary and ternary vanadium molybdenum oxides up to quaternary oxides with additional tungsten) were prepared via a solid state preparation route and hydrochemical preparation of precursors by spray-drying or crystallisation with subsequent calcination. The phase composition was investigated ex situ by XRD and HR-TEM.