Salt-in-polymer

In addition to the salt in polymer approach as described above, Angell and coworkers have described preparation of polymer-in-salt materials [44] (vide infra). Lithium salts are mixed with small amounts of poly propylene oxide and poly ethylene oxide to afford rubbery materials with low glass transition temperatures. This new class of polymer electrolytes showed good lithium ion conductivities and a high electrochemical stability. 

The irradiation of polymers in salt solutions emphasizes the aggression of electrolyte on the polymer [97Z1]. If this type of degradation takes place under radiation, the effect is amplified and greater amount of outer parts of material is removed either as fine or larger particles. However, the simultaneous generation of radicals by interaction of radiation and chloride ions with polymer increases the crosskinking level as is illustrated in Fig. 10. 

Raman spectroscopy is sensitive to both the chemical and the stmctural variations of a material, liquid or solid/ As an in situ technique, Raman spectroscopy has been used to characterize the crystalline structural variation of graphite anodes and Li vPj and LiMn O cathodes in lithium ion batteries during lithium ion insertion and extraction. In the authors laboratory, Raman spectroscopy was used to extensively study the strong interactions between the components of polyacrylonitrile (PAN)-based electrolytes, the competition between the polymer and the solvent on association with the Li ions, the ion transport mechanisms of both salt-in-polymer and polymer-in-salt electrolytes. Based on the Raman spectroscopic study, Li ion insertion and extraction mechanisms in low-temperature pyrolytic carbon anode have also been proposed. " In many cases, Raman spectroscopy is used as compensation to the IR spectroscopy to give a complete understanding to the structure of a substance though there are as many cases that Raman spectroscopy is used independently. 

Hanley TR, Helminiak TE, Benner CL (1978) Expansion of aromatic heterocyclic polymers in salt solution. J Appl Polym Sci 22 2965-2978... 

Very recently, new solid ionic conductors, so-called polymer in-salt materials, have been reported, in which lithimn salts are mixed with small quantities of the polymers PEO and PPO, while conventional polymer electrolytes ( salt-in-polymer ) contain only one Li per about ten repeat units of ether. The reported conductivity in the AlCl3-LiBr-LiC104-PP0 system is as high as 0.02 S cm at room temperature. 

A polymer-in-salt is a polymer doped with lithium salts, i.e., salts act as a predominant component, rather than polymer as the main component (salt-in-polymer) in the polymer electrolyte. Such an electrolyte salt is generally a combination of a variety of salts or ILs thus, it has a low melting point and phase separation does not occur readily. 

Besides PEO, PAN polymer can also form polymer-in-salt electrolytes. Further studies can be expected to lead to the discovery of other types of polymer electrolytes, such as polyphosphazene [23]. 

The ionic conductivity of the polymer-in-salt electrolyte may reach about 10 S/cm and even up to 10 S/cm. However, the corrosivity of most salts used in the system limits their application. 

Fan J, Marzke R F, Sanchez E and Angell C A (1994) Conductivity and nuclear spin relaxation in superionic glasses, polymer electrolytes and the new polymer-in-salt electrolyte, J Non-Cryst Solids 172-174 1178-1189. 

FERRY A, EDMAN L, FORSYTH M, MACFARLANE D R and SUN J, Connectivity, ionic interactions, and migration in a fast-ion-conducting polymer-in-salt electrolyte based on poly(acrylonitrile) and IiCF3S03 ,//lpp/ Phys, 1999,86(4), 2346-2348... 

Class 4 polymer-in-salt, or rubbery electrolytes, in which high-molar mass polymers are dissolved in low temperature molten salt mixtures. 

A careful definition of the various classes of polymer and glassy electrolytes is given by Angell et al. [85]. Utilizing these definitions, it is only the polymer in salt electrolyte (PISE) system that concerns us here. In these systems, an ionic liquid and a polymer are mixed together (the salt in excess... 

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