Alkali intercalation, layered compounds

Tributsch H (1982) Photoelectrochemical Energy Conversion Involving Transition Metal d-States and Intercalation of Layer Compounds. 49 127-175 Truter MR (1973) Structures of Organic Complexes with Alkali Metal Ions. 16 71-111 Tytko KH, Mehmke J, Kurad D (1999) Bond Length-Bond Valence Relationships, With Particular Reference to Polyoxometalate Chemistry. 93 1-64 Tytko KH (1999) A Bond Model for Polyoxometalate Ions Composed of M06 Octahedra (MOk Polyhedra with k > 4). 93 65-124... 

The layered compounds AMO2 where M is a transition metal and A an alkali metal, Cu or Ag have attracted interest because of their electrical properties. LiCo02 is used in rechargeable lithium ion batteries and Na, Co02 is metallic except at x = 0.5 and for values of x of about 0.35 becomes superconducting in the presence of intercalated water. Li et and Xu and Zeng have studied Nao.5Co02. A... 

Although there are numerous families of lamellar solids, only a handful of them exhibit the kind of versatile intercalation chemistry that forms the basis of this book. In arriving at the content of this volume, the editors have accurately identified six classes of versatile layered compounds that are at the forefront of materials intercalation chemistry, namely, smectite clays, zirconium phosphates and phos-phonates, layered double hydroxides (known informally as hydrotalcites or anionic clays ), layered manganese oxides, layered metal chalcogenides, and lamellar alkali silicates and silicic acids. Graphite and carbon nanotubes have not been included, in part because this specialty area of intercalation chemistry is limited to one or two molecular layers of comparatively small guest species that are capable of undergoing electron transfCT reactions with the host structure. 

Rouxel J (1978) Alkali metal intercalation compounds of transition metal chalcogenides TX2, TX3 and TX4 chacogenides. In Levy F (ed) Intercalated layer materials. Reidel, Dordrecht, pp 201-250... 

Graphite reacts with alkali metals, for example potassium, to form compounds which are non-stoichiometric but which all have limiting compositions (for example K C) in these, the alkaU metal atoms are intercalated between the layers of carbon atoms. In the preparation of fluorine by electrolysis of a molten fluoride with graphite electrodes the solid compound (CF) polycarbon fluoride is formed, with fluorine on each carbon atom, causing puckering of the rings. 

Figure 8.16 Layer-plane sequence along the c-axis for graphite in various stage I -5 of alkali-metal graphite intercalation compounds. Comparison with Fig. 8.15 shows that the horizontal planes are being viewed diagonally across the figure. /,. is the interlayer repeat distance along the c-axis.

One of the most widely explored systems is derived from the interpolation of Li between the TiS2 layers in varying amounts to form nonstoichiometric phases with a general formula LivTiS2. Because the bonding between the layers is weak, this process is easily reversible. The open nature of the structure allows the Li atoms to move readily in and out of the crystals, and these compounds can act as convenient alkali metal reservoirs in batteries and other devices. A battery using lithium intercalated into TiS2 as the cathode was initially developed some 30 years ago. 

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