Lithium cells intercalation

Some of the MPYj compounds, in particular NiPS3, FePSj and FePSc3, are active cathode materials in lithium cells . Intercalation can also be achieved through the butyllithium technique (see 16.4.3.2). The reaction ... 

Further, tungsten oxysulfide films, WOyS, have shown promising behavior as positive electrodes in microbatteries, unlike WS2 that is not suitable as cathode in lithium cells. Using amorphous thin films of WO1.05S2 and WO1.35S2.2 in the cell Li/LiAsFe, 1 M ethyl-methyl sulfone (EMS)/W03,Sz, Martin-Litas et al. [80] obtained current densities up to 37 xA cm between 1.6 and 3 V. In these cathode materials, 0.6 and 0.8 lithium per formula unit, respectively, could be intercalated and de-intercalated reversibly. 

Kanehori K, Matsumoto K, Miyauchi K, Kudo T (1983) Thin film solid electrolyte and its application to secondary Lithium cell. Solid State Ionics 9-10 1445-1448 Py MA, Haering RR (1983) Structural destabilization induced by lithium intercalation in M0S2 and related compounds. Can J Phys 61 76-84... 

Some of the earliest concepts came from Japan, where Matsuchita developed the Li/(CF) battery that was used, for example, in fishing floats. Lithium fluoride and carbon are the final reaction products, but the cell potential of 2.8—3.0 V suggests a different electrochemical reaction. It was proposed that lithium initially intercalates the carbon monofluoride lattice and subsequently the lithium fluoride is formedF Li + (CF)n — L CF)n C + LiF. Although much work... 

Limiting Factors for Low-Temperature Operation. One controversial topic that has raised wide attention relates to the limiting factors of the low temperature of lithium ion cells. The researchers not only debated about whether the anode or cathode controls the overall low-temperature performance of a full lithium ion cell but also disagree upon the rate-determining steps that govern the low-temperature kinetics of lithium ion intercalation at the graphitic anode. 

Fig. 7.2 Schematic diagram showing the discharge of a lithium-AzBy intercalation positive cell. (By permission of Chim Ind. B. Scrosati, 1995, 77, 285.)...

The intercalation process on the anode side takes place in stages as more and more lithium enters the crystal lattice. A typical electrolyte in lithium-ion cells contains ethylene carbonate and a mixture of aliphatic carbonates such as methyl carbonate, and ethyl methyl carbonate, along with 1M LiPF6 salt. The propylene carbonate containing electrolyte, used in primary lithium cells, could... 

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. 

Touhara H, Fujimoto H, Kadono K, Watanabe N, Endo M. Electrochemical characteristics of fluorine intercalated graphite fiber-lithium cells. Electrochim Acta 1987 32 293-298. 

Recently, fluorinated fullerenes, e. g. CgoFao. were proposed as an active material in primary lithium cells. In a mixture with graphite, discharge capacities (Li+ -intercalation and LiF formation) of 560 Ah/kg were reported [231]. 

Upon discharge lithium is intercalated. This results in shifts of the (101), (002) and (100) Bragg peaks. Detailed studies of the various shifts as functions of the state of charge/discharge reveal further information on the mechanism of the different phase transitions [12]. Reactions of lithium with Sg in a secondary Li/S cell have been tracked with in situ X-ray diffraction [15]. The electrochemical reaction... 

Using the LiAsFg/2-Me-THF solution Brummer et al. have investigated three promising secondary lithium anode/intercalation cathode cells (cf. Fig. 20) the cathode materials are TiSj, Cr Vj S2 and VgO, j. It is claimed that such cells working for 100 to 200 cycles at attractive energy densities are feasibk. Additional information can be found in a recent publication... 

Orthorhombic crystalline vanadium pentoxide is a typical intercalation compound as a result of its layered structure, see Fig. 5.2, which finds widespread use in lithium ion intercalation applications such as electrochromic cells [17], high energy density batteries [18], supercapacitors [19], and sensors [20], since it offers the essential advantages of low cost, abundant availability, easy synthesis, and high intercalation densities [15, 16]. 

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. 

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