Nanoionics

Nanostructured materials are distinguished from conventional polycrystalline materials by the size of the structural units that compose them, and they often exhibit properties that are drastically different from the polycrystalline materials. In many instances, this can be related to large fractions of grain boundaries and hence large numbers of surface atoms. Defect thermodynamics in the bulk may then be governed by surfaces. As tailoring of fundamental properties becomes possible in the quantum confinement regime, existing materials may find new applications. In this review, recent studies of the properties of nanostructured electroceramics will be presented. The applications relate to electrochemical devices for energy conversion and storage. A breakthrough in metal hydride technology was achieved by preparing nanostructured hydride forming materials. In addition, several forms of carbon are being studied for hydrogen storage. Alkali-doped carbon nanotubes and nanosized SiC powders are promising as well. Consolidation of nanosized powders by dynamic compaction techniques leads to nanostructured microstructures. Recent examples using Magnetic Pulse Compaction (MPC) will be presented. (C) 2002 Published by Elsevier Science B.V.