Nickel nitride is synthesised by high temperature ammonolysis of nickel(II) hexamine and tris(ethylenediamine) salts. Its electrochemical characteristics are examined in half cells vs lithium and sodium. Samples with high surface area are found to have significant reversible charge storage capacity in sodium cells and hence to be a promising negative electrode material for sodium-ion batteries.

A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. chlorometallate complexes we demonstrate the deposition of elemental Ga, In, Ge, Sn, Sb, Bi, Se, Te. In all cases, with the exception of Ga which is a liquid under the deposition conditions, the resulting deposits are characterised by scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction and Raman. An advantage of this electrolyte system is that the reagents are all crystalline solids that are reasonably easy to handle and that are not highly water or oxygen sensitive. The results presented here significantly broaden the range of materials accessible by electrodeposition from supercritical fluid and open the future possibility to deposit binary or ternary alloys and compounds of the p-block.

Electrodeposition of Sn from supercritical difluoromethane has been performed into anodic alumina templates with pores down to 3 nm in diameter and into mesoporous silica templates with pores of diameter 1.5 nm. Optimized deposits have been characterized using X-ray diffraction, scanning electron microscopy, and scanning transmission electron microscopy (bright field, high-angle annular dark field, and energy-dispersive X-ray elemental mapping). Crystalline 13 nm diameter Sn nanowires have been electrodeposited in symmetric pore anodic alumina. Direct transmission electron microscopy evidence of sub 7 nm Sn nanowires in asymmetric anodic alumina has been obtained. These same measurements present indirect evidence for electrodeposition through 3 nm constrictions in the same templates. A detailed transmission electron microscopy study of mesoporous silica films after Sn deposition is presented. These indicate that it is possible to deposit Sn through the 1.5 nm pores in the mesoporous films, but that the nanowires formed are not stable. Suggestions of why this is the case and how such extreme nanowires could be stabilized are presented.

We report the electrodeposition of germanium from supercritical difluoromethane (sc-CH 2 F 2 ) at 19 MPa and 358 K using [N n Bu 4 ] [GeCl 3 ]. Voltammetry shows a classic nucleation loop on the first anodic scan with a high nucleation overpotential for germanium on TiN. In all cases the deposition appears to be kinetically limited by a coupled, potential independent, chemical step. Films of germanium were deposited at a range of potentials. At high overpotentials the films were dendritic and poorly adherent. At lower overpotentials, below −2 V vs. Ag|LaF 3 , the films are smoother and more homogeneous. Analysis of the films by energy dispersive X-ray (EDX) spectroscopy shows the presence of germanium with some chloride impurity. Raman spectroscopy confirms the deposition of amorphous germanium. Plating by pulsing to −1.9 V vs. Ag|LaF 3 for 100 ms and then growth at −1.5 V vs. Ag|LaF 3 , was found to produce the best films. On annealing at 700 • C under an Ar atmosphere for 1 hour the as-deposited amorphous germanium film is converted into crystalline germanium, as determined by X-ray diffraction (XRD) and Raman spectroscopy. Since the discovery of semiconductor effects in crystalline germanium over half a century ago, 1 germanium based thin films and structures have received considerable interest. These include a number of advanced applications from doping in optics components 2 to high speed electronics, 3 and from Li-ion batteries 4 to third generation photovoltaics. 5Thin films of germanium are typically formed via vacuum processes such as chemical vapor deposition 6,7 or molecular beam epitaxy. 8 In comparison, the non-aqueous electrodeposition of germanium thin films is an attractive alternative as it has the advantages of high material efficiency, directly templated growth and fine control over the evolving structure. 9Over the previous decade Endres and his colleagues have pioneered the electrodeposition of germanium thin films from ionic liquids. [10][11][12][13][14] In this context ionic liquids have a number of advantages over conventional aqueous based solvents; they are chemically stable, they can be purified to remove impurities such as oxygen and water which can decompose the germanium precursors, and they have a wide electrochemical potential window. Initial work in ionic liquids focused on electrodeposition from the Ge(IV) reagent GeI 4 . The electrodeposition was investigated using in situ scanning tunnelling microscopy (STM) and the plated films were shown to be extremely thin (of the order of 12-16 nm) and the plating rate very slow. This self-limiting electrodeposition was attributed to the low conductivity of the deposited germanium film and complex germanium surface chemistry, possibly involving formation of a hydride, fluoride, iodide or hydroxide surface state.12 Germanium thin films have also been electrodeposited from the corresponding chloride and bromide precursors GeX 4 (X = Cl 11 or Br 10 ) in ionic liquids. Again plating rates were low and only very thin films were produced. A re...

We report results for the electrochemistry of the germanium(II) trihalide anions,