Lithium salts manufacturing

Table 15.1 Lithium salts manufactured by Nippon Chemical Industrial Co., Ltd...

Manufacture. Lithium fluoride is manufactured by the reaction of lithium carbonate or lithium hydroxide with dilute hydrofluoric acid. If the lithium carbonate is converted to the soluble bicarbonate, insolubles can be removed by filtration and a purer lithium fluoride can be made on addition of hydrofluoric acid (12). High purity material can also be made from other soluble lithium salts such as the chloride or nitrate with hydrofluoric acid or ammonium bifluoride (13). 

Lithium hydroxide monohydrate. CAS l3IO-65-2. LiOH H 0 loses water at I0LC. LiOH nidus at 450 C. The compound is soluble in water. The compound is used in the formulation of lithium soaps used in multipurpose greases also in the manufacture of various lithium salts and as an additive lo the electrolyte of alkaline storage bailerics. LiOH also is an efficient, light-weight absorbent for carbon dioxide. 

Lithium carbonate, Li2C03.—The carbonate is prepared by boiling a solution of a lithium salt with ammonium, sodium, or potassium carbonate, its slight solubility inducing crystallization and facilitating purification. A process for its manufacture from lepidolite has also been devised.2... 

Uses. — Lithium compounds are used in increasing amounts in the manufacture of glass. The. chief uses of lithium salts for some years has I men in medicine and pyrotechnics. 

Lithium has the lowest density (0.53 gcm ) of all known metals. It is used in the manufacture of alloys, and in certain glasses and ceramics. Lithium carbonate is used in the treatment of manic-depressive disorders, although large amounts of lithium salts damage the central nervous system. 

Lithium is used in making alloys, in the manufacture of lithium salts, and in vacuum tubes. 

Acetylene and ammonia, the gases, which are used in excess in this process, are almost completely recycled, the lithium salts are returned to the lithium metal manufacturer and there converted into the marketable lithium hydroxide. In the 1980s, the whole process was optimised to reduce the waste streams, and it was regarded as a classic example of an environment-friendly and economic production process. 

It is considered to be important to control the atomic ratio of Li/Co in the production of LiCoOj. One of the features of this product is that its ratio is generally less than one. The cathode slurry is prepared by dispersing the conductor and electroactive LiCoOj in the N-methyl-pyrroMone solution containing polyvinylidene fluoride (PVDF). It is unavoidable that some water is contaminated into the slurry. When the unreacted lithium in LiCoO remains as Li O, it reacts with water in the slurry, and the cathode slurry becomes basic. The cathode slurry changes to a gel state in such basic media as a result, the cathode slurry cannot be painted onto the aluminum collector. Therefore, conventional raw LiCoO is washed with warm water in order to prevent gel formation of the cathode slurry. In an example of the product supplied by a company, the pH of 10 wt% LiCoO aqueous dispersion is adjusted to 9.5-11.0. The recommended pH is less than 10.5. This manufacturer supplies LiCoOj with Li/Co < 1, so there is a possibility for making the unreacted lithium salt in the product close to 0. It can be considered that the washing process of raw LiCoOj would be removed for cost reduction. 

In 1997, Sanyo Electric Company discovered that lithium salts such as lithium fluorophosphate (Li2P03F) (173) and lithium difluorophosphate (LiP02F2) (174) can be used as additives in small quantities [162], Furthermore, in 2(X)3, Mitsubishi Chemical Corporation discovered a method for manufacturing lithium difluorophosphate (174) [163],... 

A liquid electrolyte consists of solvent(s) and supporting lithium salt(s). Their manufacturing process and purity are of great importance to the electrochemical performance of the prepared liquid electrolytes. 

MEHTA v and COOPER J s (2003), Review and analysis of PEM fuel cell design and manufacturing , / Power Sources, 114 32-53 MIWA Y, TSUTSUMi H and oiSHi T (2001), Polymerization of bis-oxetanes consisting of oligo-ethylene oxide chain with lithium salts as initiators , Polymer J, 33(8) 568-574... 

For this reason, battery manufacturers are reluctant to fabricate batteries based on lithium metal. The only way to safely use lithium as an electrode is by coupling it with a stable electrolyte. The most common examples are sol-vent-free, polymer membranes formed by the combination of a poly(ethylene oxide) (PEO) matrix and a lithium salt, LiX [5,6]. The excess of negative charge on the oxygen in the PEO chains coordinates by coulombic attraction of the Li+ ions, thus separating them from the anions. By this process, the lithium salt is dissolved in the PEO matrix, analogous to the process of salt dissolution in liquid solvents [5]. The main difference is that while the ions can move with their solvation shell in liquids, this is not possible in the PEO complexes due to the large size and encumbrance of the chains. Therefore, ion transport in the polymer electrolytes requires flexibility of the PEO chains so... 

Solid polymer and gel polymer electrolytes could be viewed as the special variation of the solution-type electrolyte. In the former, the solvents are polar macromolecules that dissolve salts, while, in the latter, only a small portion of high polymer is employed as the mechanical matrix, which is either soaked with or swollen by essentially the same liquid electrolytes. One exception exists molten salt (ionic liquid) electrolytes where no solvent is present and the dissociation of opposite ions is solely achieved by the thermal disintegration of the salt lattice (melting). Polymer electrolyte will be reviewed in section 8 ( Novel Electrolyte Systems ), although lithium ion technology based on gel polymer electrolytes has in fact entered the market and accounted for 4% of lithium ion cells manufactured in 2000. On the other hand, ionic liquid electrolytes will be omitted, due to both the limited literature concerning this topic and the fact that the application of ionic liquid electrolytes in lithium ion devices remains dubious. Since most of the ionic liquid systems are still in a supercooled state at ambient temperature, it is unlikely that the metastable liquid state could be maintained in an actual electrochemical device, wherein electrode materials would serve as effective nucleation sites for crystallization. 

The above merits made LiPFe the salt of choice when lithium ion technology leaped from concept into product. In 1990, it was used by Sony in the first generation lithium ion cell, and since then, its position in the lithium ion industry has remained unchallenged. Like EC as an indispensable solvent component, LiPFe has become the indispensable electrolyte solute for almost all lithium ion devices manufactured in the past decade. 

---