Solvated lithium ion

Whereas the electrochemical decomposition of propylene carbonate (PC) on graphite electrodes at potentials between 1 and 0.8 V vs. Li/Li was already reported in 1970 [140], it took about four years to find out that this reaction is accompanied by a partially reversible electrochemical intercalation of solvated lithium ions, Li (solv)y, into the graphite host [64], In general, the intercalation of Li (and other alkali-metal) ions from electrolytes with organic donor solvents into fairly crystalline graphitic carbons quite often yields solvated (ternary) lithiated graphites, Li r(solv)yC 1 (Fig. 8) [7,24,26,65,66,141-146],... 

These morphological changes (hill and blister formation) were attributed to the intercalation of solvated lithium ion into graphite interlayers and to the accumulation of its decomposition products (some of them gases), respectively. On the other hand, rapid exfoliation and rupturing of graphite layers were observed in ImolL-1... 

One of the most important factors affecting Qsei [76, 78, 87] is graphite-anode exfoliation, as a result of intercalation of solvated lithium ions. Factors that are reported to decrease (9lR are increasing the EC content in organic carbonates or di-oxolane solutions [98, 991 addition of C02 [31, 87, 99] or crown ethers [8, 71, 78] and increasing the current density [73] (this also lowers <2SE [14] as a result of decrease in (2s P ) ... 

It is worth mentioning that single-ion conductivities of lithium ions and anions at infinite dilution, and transference numbers of ligand-solvated lithium ions estimated therefrom, increase due to the replacement of more than one (generally four) solvent molecules. Table 6 demonstrates this beneficial feature. 

Table 6. Single-ion conductivities of solvated lithium ions and anions at 25 °C in PC at infinite dilution [13]...

The HRTEM observation of the cross section of a coated fiber showed that the core is constituted of aromatic layers highly misoriented, whereas they are preferentially oriented in parallel for the thin coating pairs of stacked layers form mainly Basic Structural Units (BSUs) in which the average interlayer distance is smaller than between the aromatic layers in the bulk of the fiber. Since the nanotexture is more dense for the pyrolytic carbon than for the fiber itself, it acts as a barrier which prevents the diffusion of the large solvated lithium ions to the core of the fiber, allowing the passivation layer to be less developed after this treatment. Hence, the major amount of lithium inserted is involved in the reversible contribution therefore this composite material is extremely interesting for the in-situ 7Li NMR study of the reversible insertion. 

The study of solvated alkali metal allyl species remains a complex topic due to a variety of reorganization processes. Structural data on alkali metal allyl derivatives include [G3H5Li(TMEDA)] 133,139 where solvated lithium ions act as... 

Although the reagent is written as LiAlH4 but interpreted as Li [AlH4] or Li+ A1H4. In ether solution, it exists as aggregates of solvated lithium ions and aluminus-hydride ions. 

The reduction of the maleic anhydride adduct (303) with lithium aluminium hydride was previously reported to occur selectively to give the lactone (304). The lower selectivity now observed with sodium aluminium hydride (none at all with sodium borohydride) is interpreted as evidence for a complex (305) of the ester and anhydride carbonyl groups with a solvated lithium ion when lithium aluminium hydride is used, leading to selective reduction of the free carbonyl group.Sodium ions are considered not to form so stable a complex. 

The formula of the reagent is usually written as LiAlHi but interpreted as Li fAlH,]" or Li+A1H4. Thus in ether solution it exists as aggregates of solvated lithium ions and aluminohydride ions. The first step in the reaction with a ketone is transfer of a hydride ion to give the complex (1) since this has three more hydrogen... 

These better results obtained by PEO and LiCl may be due to an effective adsorption of TPA on PEO through solvated lithium ion. 

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