Molecular insights: structure and dynamics of a Li ion doped organic ionic plastic crystal.

A molecular-level understanding of why the addition of lithium salts to Organic Ionic Plastic Crystals (OIPCs) produces excellent ionic conductivity is described for the first time. These materials are promising electrolytes for safe, robust lithium batteries, and have been experimentally characterised in some detail. Here, molecular dynamics simulations demonstrate the effects of lithium ion doping on both the structure and dynamics of an OIPC matrix (tetramethylammonium dicyanamide [TMA][DCA]) and illustrate a molecular-level transport model: in the plastic crystal phase lithium ions can form clusters with [DCA](-), and this clustering then in turn creates free volume or defect paths in the remainder of the lattice, which enhances ion conduction.

Monte Carlo calculations of the free energy of binary sII hydrogen clathrate hydrates for identifying efficient promoter molecules.

The thermodynamics of binary sII hydrogen clathrates with secondary guest molecules is studied with Monte Carlo simulations. The small cages of the sII unit cell are occupied by one H(2) guest molecule. Different promoter molecules entrapped in the large cages are considered.

Combining the pair distribution function and computational methods to understand lithium insertion in Brookite (TiO2).

X-ray pair distribution function (PDF) methods and first-principles calculations have been combined to probe the structure of electrochemically lithiated TiO(2) Brookite. Traditional powder diffraction studies suggest that Brookite amorphizes upon lithium insertion, with the Bragg reflections disappearing. However, PDF analysis indicates that the TiO(2) framework connectivity is maintained throughout lithium intercalation, with expansions along the a and b axes.

Mechanism of Li-insertion into spinel-structured Li0.5TiO2.

First-principles calculations of Li-insertion into spinel-structured titanate Li(0.5)TiO2 reveal a mechanism underlying the intercalation behaviour of this material. A key factor is the accommodation of charge density transferred to the host lattice upon lithium insertion.