Electrolyte nonaqueous

For any type of nonaqueous electrolyte (nonaqueous solutions, melts, solid electrolytes) we can select suitable reference electrodes, measure the potentials of other electrodes, and set up tables of electrode potentials. The order of the reactions (electrodes) as a rule does not strongly differ between the different media. A strong reducing agent such as lithium will have a more negative potential than a weaker reducing agent such as copper, both in water and in other media. 

The standard potentials of other metals, such as alkali metals, alkaline earth metals, aluminum, or titanium are so negative that these metals caimot be deposited from aqueous solutions. By choosing electrolytes which do not contain protons and strong complexing groups, it is possible to electrolytically deposit such metals which are not obtainable from aqueous electrolytes. Nonaqueous electrolytes may be either fused salts or solutions of metal compounds in organic or inorganic solvents. 

Indifferent electrolyte -> supporting electrolyte nonaqueous electrolyte — Common solvents for nonaqueous electrolytes are alcohols, acids, amines, ethers, nitriles, amides, dimethyl sulfoxide, and methylene chloride. The first two groups of compounds are amphiprotic, amines are protophilic, and the others are aprotic solvents. They are used for the investigation of electrochemical properties of organic compounds, but this is not a general rule. Some examples are given below [i]. 

Electrolytic Solvent. The use of DMAC as a nonaqueous electrolytic solvent is promising because salts are modesdy soluble ia DMAC and appear to be completely dissociated ia dilute solutions (18). 

New Synthesis. Many attempts have been made to synthesize oxaUc acid by electrochemical reduction of carbon dioxide in either aqueous or nonaqueous electrolytes (53—57). For instance, oxaUc acid is prepared from CO2 as its Zn salt in an undivided ceU with Zn anodes and stainless steel cathodes ia acetonitrile containing (C4H2)4NC104 and current efficiency of >90% (53). Micropilot experiments and a process design were also made. 

Micellar properties are affected by changes in the environment, eg, temperature, solvents, electrolytes, and solubilized components. These changes include compHcated phase changes, viscosity effects, gel formation, and Hquefication of Hquid crystals. Of the simpler changes, high concentrations of water-soluble alcohols in aqueous solution often dissolve micelles and in nonaqueous solvents addition of water frequendy causes a sharp increase in micellar size. 

Lithium batteries must use nonaqueous electrolytes, usually combinations of solvents, for stabiUty because lithium reacts readily with water. Many of... 

Most battery systems in which lithium is applied as anode material belong to the group using nonaqueous electrolytes, but there is one system that works with water serving as solvent and reactant as well. 

The composition, structure, and formation process of the SEI on metallic lithium depend on the nature of the electrolyte. The variety of possible electrolyte components makes this topic very complex it is reviewed by Peled, Golodnitsky, and Penciner in Chapter III, Sec.6 of this handbook. The types and properties of liquid nonaqueous electrolytes, that are commonly used in lithium cells are reviewed by Barthel and Gores in Chapter III, Sec.7. 

Film-forming chemical reactions and the chemical composition of the film formed on lithium in nonaqueous aprotic liquid electrolytes are reviewed by Dominey [7], SEI formation on carbon and graphite anodes in liquid electrolytes has been reviewed by Dahn et al. [8], In addition to the evolution of new systems, new techniques have recently been adapted to the study of the electrode surface and the chemical and physical properties of the SEI. The most important of these are X-ray photoelectron spectroscopy (XPS), SEM, X-ray diffraction (XRD), Raman spectroscopy, scanning tunneling microscopy (STM), energy-dispersive X-ray spectroscopy (EDS), FTIR, NMR, EPR, calorimetry, DSC, TGA, use of quartz-crystal microbalance (QCMB) and atomic force microscopy (AFM). 

This section reports on the current state of knowledge on nonaqueous electrolytes for lithium batteries and lithium-ion batteries. The term electrolyte in the current text refers to an ion-conducting solution which consists of a solvent S and a salt, here generally a lithium salt. Often 1 1-salts of the LiX type are preferred for reasons given below only a few l 2-salts Li2X have attained some importance for batteries, and 1 3-salts Li3X are not in use. 

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