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We present a comparative, combined ab initio and experimental study of sodium and lithium storage in amorphous (glassy) carbon (a-C) vs. graphite. Amorphous structures are obtained by fitting stochastically generated structures to a reference radial distribution function.Li insertion is thermodynamically favored in both graphite and a-C. While sodium insertion is thermodynamically unfavored in graphite, a-C possesses multiple insertion sites with binding energies stronger than Na cohesive energy, making it usable as anode material for Na-ion batteries. Binding energy of Na is predicted to be stronger than the Na cohesive energy for Na concentrations corresponding to a capacity of about 200 mAh/g. These results are confirmed by experimental measurements using highly amorphous carbon, in which a specific capacity of 173 mAh/g for Na is obtained after 100 cycles.

This paper is a collection of selected contributions of the 1st International Workshop on Mechanochemistry of Metal Hydrides that was held in Oslo in May 2018. In this paper, the recent developments in the use of mechanochemistry to synthesize and modify metal hydrides are reviewed. A special emphasis is made on new techniques beside the traditional way of ball milling. High energy milling, ball milling under hydrogen reactive gas, cryomilling and severe plastic deformation techniques such as High-Pressure Torsion (HPT), Surface Mechanical Attrition Treatment (SMAT) and cold rolling are discussed. The new characterization method of in-situ X-ray diffraction during milling is described.

The thermal phase behaviour of cryomilled a 0 -AlD 3 and a-AlD 3 was investigated by in situ synchrotron powder X-ray diffraction (SR-PXD), differential scanning calorimetry and first principles atomic modelling. In situ measurements showed that a 0 -AlD 3 decomposes directly into Al and D 2 at around 80 C during heating at 1 C min À1 . At higher temperatures the transformation of a 0 -AlD 3 to a-AlD 3 was observed by DSC measurements at 5 C min À1 , and tentatively by in situ SR-PXD at 1 C min À1 . Atomic modelling was carried out to investigate possible structural relationships and transformation pathways between the aand a 0 -phase. Group-subgroup relation analyses and direct method lattice dynamics were used to rule out a possible displacive transformation pathway between the a 0 -and a-phases. The likelihood of a reconstructive transformation was demonstrated by partial transformation of an interface between a 0 and a domains during elevated temperature molecular dynamics. Such an a 0 -to a-phase transformation may be possible when kinetic barriers can be overcome at elevated temperatures or during long time periods. These insights are also relevant to the transformation mechanisms of the b-AlD 3 and g-AlD 3 isomorphs to the a-phase.

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