Lithium salts anions

Table 4 lists selected electrochemical stability data for various lithium salt anions that are commonly used in lithium-based electrolytes, with the measurement approaches indicated. Although it has been known that the reduction of anions does occur, sometimes at high potentials, the corresponding processes are usually sluggish and a definite potential for such reductions is often hard to determine. The reduction of solvents, occurring simultaneously with that of anions on the electrode, further complicates the interpretation efforts. For this reason, only the anodic stability of salt anions is of interest, while the cathodic limit of the salt in most cases is set by the reduction of its cation (i.e., lithium deposition potential). 

Fig. 1.3 Widely used lithium salt anions (a) AsFg", (b) PFg, (c) CIO4", (d) BF4, (e) SO3CF3", and (f) N(S02CF3>2" (TFSL) (C (fits) and Ci (tram) conformations) (B—tan, C—gray, N—blue, O—red, F—light green, P—orange, S—yellow, Q—dark green. As—purple)...

Lithium salt (anion) Conductivity (mS cm ) Lithium salt (anion) Conductivity (mS cm )... 

The simplest model, still capable of addressing different electronic states, is an isolated molecular species - be it neutral (as electrolyte solvent or a redox shuttle additive) or charged (like a lithium salt anion or an oxidized redox shuttle). This is by far the most common model employed for any strategy and method combination. 

Prediction of salt electrochemical stability in the context of Li-ion batteries has mainly involved predicting the Eox of novel lithium salt anions, frequently without any focus on the subsequent decomposition reaction products and mechanisms. However, with recent results on oxidation promoted solvent-anion reactions [57] and the rapid development of solvent-free ionic liquid (IL) electrolytes, investigations of both anion and cation decomposition products are foreseen by us to become more frequent and important - particularly in connection with the passivation phenomena at the negative electrode. As for solvents, we will here follow the historical development of studies and methods, followed by some more recent works that together with our remarks outline our perspective on the future. 

Evidence for the formation of some type of Solid Permeable Interface (SPI) has been obtained in all cases smdied. It can be stated generally that the organic species formed on the different cathode electrodes are more or less the same varying more in degree than in their precise chemical nature layer thickness also vary from material to material they also tend to increase significantly with temperature. However, the inorganic species found are more dependent on electrode material type. Reactions with the lithium-salt anion used are also material dependent. It is especially important to reduce the impact of the PF anion and its related contaminants (HF and PF,) on electrode surface chemistry through the implementation of more stable salts. Such a development is currently underway. 

Ionic polymers may exist as undissociated, unsolvated ion pairs undissociated ion pairs solvated to some extent solvated ions dissociated to some extent or some combination of these. The propagation rate constant kp and the dissociation equilibrium constant K of the lithium salt of anionic... 

Compare atomic charges for the enolate anion and the lithium salt. Are there major differences, in particular, for the oxygen and the a carbon Also compare the highest-occupied molecular orbital (HOMO) in the two molecules. This identifies the most nucleophilic sites, that is, the most likely sites for attack by electrophiles. Are the two orbitals similar or do they differ substantially Elaborate. 

Do changes in geometries, charges and size and shape of the HOMO between the enolate anion and its lithium salt suggest differences in reactivities If so, what differences are to be expected ... 

The lithium salt of 2-(di-wo-propylamino)-l,2-thiaborolide with [( -Cp ) RuC1]4 or [(i -Cp )ZrCl3] yields sandwiches similar to 39 (M = Ru, ZrCl2) (OOOM4935). The same anionic ligand enters a sequence of reactions with dimethylchlorosilane, lithium cyclopentadienyl, lithium di-wo-propylamide, and zirconium(IV) chloride to give sandwich 41. 

Reaction of 2-chloromethyl-4//-pyrido[l,2-u]pyrimidine-4-one 162 with various nitronate anions (4 equiv) under phase-transfer conditions with BU4NOH in H2O and CH2CI2 under photo-stimulation gave 2-ethylenic derivatives 164 (01H(55)535). These alkenes 164 were formed by single electron transfer C-alkylation and base-promoted HNO2 elimination from 163. When the ethylenic derivative 164 (R = R ) was unsymmetrical, only the E isomer was isolated. Compound 162 was treated with S-nucleophiles (sodium salt of benzyl mercaptan and benzenesulfinic acid) and the lithium salt of 4-hydroxycoumarin to give compounds 165-167, respectively. 

The same lithium salts with copper(I) chloride react through the stage of the anionic C-coordinated complexes 100, which on protonation with hydrochloric acid give the corresponding 2,2 -bithiazoles, with triflic acid— the N-coordinated species 101, and on methylation with methyl triflate they give carbenes of structure 102. 

Comparison of stability limits of low-temperature molten salts and lithium salts with a common anion shows the influence of the solvent, which limits the anodic stability range of solutions based on LiMe or Lilm. The 1,2-dimethyl-3-propylimidazolium methide... 

Unfortunately, both lithium and the lithiated carbons used as the anode in lithium ion batteries (Li C, l>x>0) are thermodynamically unstable relative to solvent molecules containing polar bonds such as C-O, C-N, or C-S, and to many anions of lithium salts, solvent or salt impurities (such as water, carbon dioxide, or nitrogen), and intentionally added traces of reactive substances (additives). 

Radii of anions of lithium salts and limiting molar conductivities in solvents of... 

Fluorination of anions of lithium salts offers a possibility for a study of the influence of ion association on the maxima of conductivity, because fluorination of large molecular anions only slightly affects the anionic radius and all other conductivity determining effects (1-3, 5, 6) are elimi-... 

The first report on the carboxylation of an a-sulfinyl anion showed that the lithium salt of (S)-(methylsulfmylmethyl)benzene treated with carbon dioxide afforded (/ ,SS)-2-(mcthyl-sulfinyDphenylacetic acid, which was isolated in 30% yield after crystallization of the crude product64. 

Addition of 2-butenyl sulfone anions to 2-cyclopentenone and 2-cyclohexenone at low temperatures ( — 85 °C) gives mixtures of y-1, 4- and a-1,2-addition products. When these reactions are warmed to 1 2CC, then y-l,4-addition products predominate7,8. The lithium salts of the a-1,2-adducts rearrange to 1,4-adducts at 0°C. 

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