New materials hold the key to fundamental advances in energy conversion and storage, both of which are vital in order to meet the challenge of global warming and the finite nature of fossil fuels. Nanomaterials in particular offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. This review describes some recent developments in the discovery of nanoelectrolytes and nanoelectrodes for lithium batteries, fuel cells and supercapacitors. The advantages and disadvantages of the nanoscale in materials design for such devices are highlighted.

Energy storage is more important today than at any time in human history. Future generations of rechargeable lithium batteries are required to power portable electronic devices (cellphones, laptop computers etc.), store electricity from renewable sources, and as a vital component in new hybrid electric vehicles. To achieve the increase in energy and power density essential to meet the future challenges of energy storage, new materials chemistry, and especially new nanomaterials chemistry, is essential. We must find ways of synthesizing new nanomaterials with new properties or combinations of properties, for use as electrodes and electrolytes in lithium batteries. Herein we review some of the recent scientific advances in nanomaterials, and especially in nanostructured materials, for rechargeable lithium-ion batteries.

Ionic liquids are room-temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer-electrolyte-membrane fuel cells), fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic-liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.

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Nature © Macmillan Publishers Ltd 19988 letters to nature 456 NATURE | VOL 394 | 30 JULY 1998 amount to Ϯ10%, this would result in a total T c variation of 7 K in the bulk phase diagram. In strained films a total variation of ϳ40 K is observed, together with a drastic change in T ‫ء‬ . Hence, the lattice deformations associated with the strain fundamentally modify the energy scales, leading to the formation and condensation of the superconducting pairs. As the pair formation strongly influences the spin and charge excitation spectrum of the normal state, r(T) and the metal-insulator transition are also considerably modified. Further work to identify and quantify the subtle lattice deformations responsible for these changes needs to be done. In any case, the data reported here emphasize that T c increases as the distance between consecutive CuO 2 planes increases, in contradiction of a recent theoretical prediction 30 . Our data also show that adjustment of the epitaxial strain offers a unique way to increase T c and to reveal the fundamental role played by the interlayer coupling. Ⅺ