Lithium graphite compounds

The first lithiated graphitic carbons (lithium-graphite intercalation compounds, abbreviated as Li-GIC s),... 

The intercalation compounds of lithium with graphite are very different in their behavior from intercalation compounds with oxides or halcogenides. Intercalation processes in the former compounds occur in the potential region from 0 to 0.4 V vs. the potential of the lithium electrode. Thus, the thermodynamic activity of lithium in these compounds is close to that for metallic lithium. For this reason, lithium intercalation compounds of graphite can be used as negative electrodes in batteries rather than the difficultly of handling metallic lithium, which is difficult to handle. 

Due to its high energy density (3,860 mAh/g) and low voltage, lithium is the most attractive metal of the periodic table for battery application. Unfortunately lithium metal, and most of its alloys cannot be used in rechargeable batteries because of their poor cyclability. Therefore, lithium intercalation compounds and reversible alloys are among today s materials of choice for subject application. The most common active materials for the negative electrodes in lithium-ion battery applications are carbonaceous materials. The ability of graphitized carbonaceous materials to... 

Billaud D., Henry F.X. and Willmann P. Electrochemical Synthesis of Binary Graphite-Lithium Intercalation Compounds. Mat. Res. Bull., 28, 477-483 (1993). 

In lithium polymer batteries, one electrode is lithium foil, or in some cases another electrically conducting material such as graphite, and the other is a reversible intercalation compound as in liquid electrolyte lithium batteries. Compounds used as intercalation electrodes include LiCo02 and VeOis. The cell developed in the Anglo-Danish project, which ran from 1979 to 1995, was... 

It is believed that the discharge mechanism involves the formation of an intermediate lithium intercalation compound in which both lithium and fluorine are situated between the carbon layers of the graphitic structure. The carbon formed is graphitic and improves the cell performance as the discharge progresses, leading to a high cathode utilization - close to 100% for low currents. The lithium fluoride precipitates. 

Ohno, T. 1980. Electronic band structure of lithium-graphite intercalation compound C6Li../. Phys. Soc. Jpn. 49(Suppl. A) 899-902. 

Morkovich, V. Z. 1996. Synthesis and XPS investigation of superdense lithium-graphite intercalation compound, LiC2. Synth. Metals 80 243-247. 

Delhaes P, Manceau KP, Guerard D. Physical properties of first and second stage lithium graphite intercalation compounds. Synth Met 1980 2 277-284. 

Ohzuku T, Iwakoshi Y, Sawai K. Formation of lithium-graphite intercalation compounds in nonaqueous electrolytes and their application as a negative electrode for a lithium ion (shuttlecock) cell. J Electrochem Soc 1993 140 2490-2498. 

Holzapfel M, Buqa H, Krumeich F, Novak P, Petrat FM, Veit C. Chemical vapor deposited silicon/ graphite compound materials as negative electrode for lithium-ion batteries. Electrochem Solid-State Lett 2005 8 A516-A520. 

The details of the EPR investigation of the graphite compound MCl6BF4M merit some discussion. Because the material is an electronic conductor, we suspended the polycrystalline sample in eicosane, melted the mixture under hot water, vibrated the sample to get random orientation, and froze the mixture under cold water. Because "CifcBF is an anisotropic conductor (it does not have metallic conductivity orthogonal to the planes), the interpretation of the EPR results requires care. Thus, in a thick plate of an isotropic metal as lithium, one observes a Dysonian asymmetry parameter A/B which is dependent on temperature, varying between... 

Group 1. - 7Li NMR spectroscopy was used to characterise a lithium/ graphite intercalation compound with a formula close to LiC 1 In situ solid-state 7Li NMR data were reported for lithium inserted into disordered carbon. There was evidence for both Lis+ and metallic lithium species.2 7Li and 13C solid-state NMR spectra were used to characterise a mesoporous tantalum oxide lithium fulleride (Ceo) composite material.3... 

Graphite compounds of rubidium and cesium seem to be more stable and to be formed easily. This is of technical importance since the absorption of the fission elements rubidium and cesium by graphite immersed in liquid sodium will be applied to remove them from the sodium coolant of a fast neutron reactor The formation of a lithium compound of this type has never been observed. 

On the other hand, the high conductivity of the gel electrolytes may be exploited in an effective way by directing them to the development of new-design, plastic-like batteries where the lithium metal anode is replaced by a lithium-accepting compound, such as a carbon or graphite [75]. These are the so-called rocking chair or, more commonly lithium-ion batteries [76]. Basically, these batteries operate on the cyclic transport of lithium ions from one lithium-... 

Another important feature for lithium graphite intercalation compounds in Li -containing electrolytes is the formation of solid electrolyte interface (SEI) film. During the first-cycle discharge of a lithium/carbon cell, a part of lithium atoms transferred to the carbon electrode electrochemically will react with the nonaque-ous solvent, which contributes to the initial irreversible capacity. The reaction products form a Lb-conducting and electronically insulating layer on the carbon surface. Peled named this film as SEI. Once SEI formed, reversible Lb intercalation into carbon, through SEI film, may take place even if the carbon electrode potential is always lower than the electrolyte decomposition potential, whereas further electrolyte decomposition on the carbon electrode will be prevented. 

Eunabiki A, Inaba M, Abe T, Ogumi Z (1999) Nucleation and phase-boundary movement upon stage transformation in lithium-graphite intercalation compounds. Electrochim Acta 45 865... 

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