Structural And Electrical Properties Of Graphite Intercalation Compounds And Graphite Fiber Compounds

Graphite intercalation compounds are a new class of electronic materials that are classified as graphite-based host guest systems. They have specific structural features based on the alternating stacking of graphite and guest intercalate sheets. The electronic structures show two-dimensional metallic properties with a large variety of features including superconductivity. They are also interesting from the point of two-dimensional magnetic systems. This book presents the synthesis, crystal structures, phase transitions, lattice dynamics, electronic structures, electron transport properties, magnetic properties, surface phenomena, and applications of graphite intercalation compounds. The applications covered include batteries, highly conductive graphite fibers, exfoliated graphite and intercalated fullerenes and nanotubes.

The research on graphite intercalation compounds often acts as a forerunner for research in other sciences. For instance, the concept of staging, which is fundamental to graphite intercalation compounds, is also relevant to surface science in connection with adsorbates on metal surfaces and to high-temperature superconducting oxide layer materials. Phonon-folding and mode-splitting effects are not only basic to graphite intercalation compounds but also to polytypical systems such as supercon ductors, superlattices, and metal and semiconductor superlattices. Charge transfer effects playa tremendously important role in many areas, and they can be most easily and fundamentally studied with intercalated graphite. This list could be augmented with many more examples. The important message, however, is that graphite inter calation compounds represent a class of materials that not only can be used for testing a variety of condensed-matter concepts, but also stimulates new ideas and approaches. This volume is the second of a two-volume set. The first volume addressed the structural and dynamical aspects of graphite intercalation compounds, together with the chemistry and intercalation of new compounds. This second volume provides an up-to-date status report from expert researchers on the transport, magnetic, elec tronic and optical properties ofthis unique class of materials. The band-structure cal culations of the various donor and acceptor compounds are discussed in depth, and detailed reviews are provided ofthe experimental verification ofthe electronic struc ture in terms of their photoemission spectra and optical properties.

There is a clear need for high-strength, lightweight composites with improved electrical conductivity. Composites fabricated from intercalated graphite fiber show promise in satisfying that need. This research focused on the chemical aspects of fiber intercalation, stability of intercalated fibers and their relation to the mechanical and electrical properties of their epoxy composites. Early work on this project helped pin down the mechanism of formation of so-called acceptor compounds of graphite as one of oxidation by election transfer to highly electrophylic species. We then established that, at least in the prototype graphite nitrate, neutral species could be removed under vacuum, and that these labile acid species must be removed before stable composites could be prepared from the intercalated fiber. In addition, we studied the kinetics of nitric acid intercalation of graphite fiber and powder and highly ordered pyrolytic graphite and offerred a proposed mechanism based on crystallite size. Epoxy composites were fabricated from graphite fiber intercalated with nitric acid.

The progress of materials science depends on the development of novel materials and the development of novel experimental techniques. The research on graphite intercalation compounds combines both aspects: new compounds with strikingly new and anisotropic properties have been synthesized and analyzed during the past couple of years by means of state-of-the-art experimental methods. At the same time, the preparation of the compounds already known has improved con siderably, giving increased reliability and reproducibility of the experimental results. The high quality experimental data now available have stimulated theo retical work. Moreover, the theoretical work has had a great impact on further experimental studies, with the effect of a much improved understanding of this class of materials. This volume is dedicated to a thorough description of all relevant experimen tal and theoretical aspects of the structural and dynamical properties of graphite intercalation compounds. Because of the large number of topics, a second vol ume, which is now in preparation, will follow and will treat the electronic, transport, magnetic, and optical properties. The second volume will also contain a chapter on applications of graphite intercalation compounds. There have been a number of reviews written on selected aspects of these compounds in various journals and conference proceedings during the last couple of years, but this is the first comprehensive review since the thorough overview provided by M.S. Dresselhaus and G. Dresselhaus appeared ten years ago.

This book covers the basic physics and chemistry of graphite intercalation compounds. Emphasis is laid on the layered or quasi-two-dimensional structure of these compounds, which provides an exciting arena for testing physical concepts in lower dimensions. The chapters in this volume, all of which have been written by internationally recognized experts in the field, cover the following topics: the structure and phase transitions of intercalate atoms and molecules in graphite, the physics of staging formation and staging transitions, the lattice dynamics of these compounds as determined by inelastic neutron scattering and optical methods, the diffusivity of the guest species, mesoscopic properties such as domain structures and stacking arrangements, and the synthesis of new compounds. The reviews provide a comprehensive overview of the current status of the field of two- dimensional physics.

The research on graphite intercalation compounds often acts as a forerunner for research in other sciences. For instance, the concept of staging, which is fundamental to graphite intercalation compounds, is also relevant to surface science in connection with adsorbates on metal surfaces and to high-temperature superconducting oxide layer materials. Phonon-folding and mode-splitting effects are not only basic to graphite intercalation compounds but also to polytypical systems such as supercon ductors, superlattices, and metal and semiconductor superlattices. Charge transfer effects playa tremendously important role in many areas, and they can be most easily and fundamentally studied with intercalated graphite. This list could be augmented with many more examples. The important message, however, is that graphite inter calation compounds represent a class of materials that not only can be used for testing a variety of condensed-matter concepts, but also stimulates new ideas and approaches. This volume is the second of a two-volume set. The first volume addressed the structural and dynamical aspects of graphite intercalation compounds, together with the chemistry and intercalation of new compounds. This second volume provides an up-to-date status report from expert researchers on the transport, magnetic, elec tronic and optical properties ofthis unique class of materials. The band-structure cal culations of the various donor and acceptor compounds are discussed in depth, and detailed reviews are provided ofthe experimental verification ofthe electronic struc ture in terms of their photoemission spectra and optical properties.