Polyethylene based electrolytes

Room temperature sensors based on a V2O5-graphite cathode and a polyethylene oxide-based electrolyte were reported by Sathiyamoorthi etal. [55]. The gas is sampled through the porous cathode and for both chlorine and fluorine good sensitivity and rapid response times were observed. 

The early batteries used polyethylene oxide (PEO)-based electrolytes containing a Uthium salt, which have an appreciable conductivity at about 100°C but low conductivity at room temperature. Later new polymeric electrolyte materials, sucb as PEO copolymers, PEO blends, plasticized PEO electrolytes, and gelled electrolytes, with better conductivity were developed. Some of the cathode materials investigated for these batteries are TiS2, VO V2O5, Li Co02 and sulfur-based polymers. 

Masson, J.P., Mofina, R., Roth, E., Gaussens, G., and Lemaire, F. Obtention and evaluation of polyethylene-based solid polymer electrolyte membranes for hydrogen-production. International Journal of Hydrogen Energy, 7(2), 167-171, 1982. 

SUN, H.Y., TAKEDA, Y., IMANISHI, N., YAMAMOTO, 0. and soHN, H., 2000. FeiToelectric materials as a ceramic filler in solid composite polyethylene oxide-based electrolytes. Journal of the Electrochemical Society, 147(7), 2462-2467. 

State-of-the-art thin film Li" cells comprise carbon-based anodes (non-graphitic or graphite), solid polymer electrolytes (such as those formed by solvent-free membranes, for example, polyethylene oxide, PEO, and a lithium salt like LiPFe or LiCFsSOs), and metal oxide based cathodes, in particular mixed or doped oxides... 

Ion exchangers are polymer electrolytes prepared a priori as insoluble solids (salts, acids, bases hydrated, possibly gel-Uke). Their polymer backbone is three-dimensional. Many are polyvinyl compounds (substituted polyethylenes) having the general formula [-CH2-CXH-] , where different substituents X lead to rather different products ... 

The PEO salt complexes are generally prepared by direct interaction in solution for soluble systems or by immersion method, soaking the network cross-linked PEO in the appropriate salt solution [52-57]. Besides PEO, poly(propylene)oxide, poly(ethylene)suceinate, poly(epichlorohydrin), and polyethylene imine) have also been explored as base polymers for solid electrolytes [58]. Polyethylene imine) (PEI) is prepared by the ring-opening polymerization of 2-methyloxazoline. Solid solutions of PEI and Nal are obtained by dissolving both in acetonitrile (80 °C) followed by cooling to room temperature and solvent evaporation in vacuo. Polyethyleneimine-NaCF3S03 complexes have also been explored [59],... 

Polyethylene oxide) associates in solution with certain electrolytes (48—52). For example, high molecular weight species of poly(ethylene oxide) readily dissolve in methanol that contains 0.5 wt % KI, although the resin does not remain in methanol solution at room temperature. This salting-in effect has been attributed to ion binding, which prevents coagulation in the nonsolvent. Complexes with electrolytes, in particular lithium salts, have received widespread attention on account of the potential for using these materials in a polymeric battery. The performance of solid electrolytes based on poly(ethylene oxide) in terms of ion transport and conductivity has been discussed (53—58). The use of complexes of poly(ethylene oxide) in analytical chemistry has also been reviewed (59). 

Another interface that needs to be mentioned in the context of polarized interfaces is the interface between the insulator and the electrolyte. It has been proposed as a means for realization of adsorption-based potentiometric sensors using Teflon, polyethylene, and other hydrophobic polymers of low dielectric constant Z>2, which can serve as the substrates for immobilized charged biomolecules. This type of interface happens also to be the largest area interface on this planet the interface between air (insulator) and sea water (electrolyte). This interface behaves differently from the one found in a typical metal-electrolyte electrode. When an ion approaches such an interface from an aqueous solution (dielectric constant Di) an image charge is formed in the insulator. In other words, the interface acts as an electrostatic mirror. The two charges repel each other, due to the low dielectric constant (Williams, 1975). This repulsion is called the Born repulsion H, and it is given by (5.10). 

In addition, various gel electrolytes were investigated for EDLC as well. Polyethylene oxide) (PEO)-, poly(acrylonitrile) (PAN)-, polymethylmethacrylate) (PMMA)- and poly(vinylidene flouride) (PVdF)-based gel electrolytes, which have been applied for secondary lithium batteries [5-7,50,51,64], were also studied as electrolyte systems for EDLC with carbon electrodes [65-68],... 

Solid electrolytes for lithium-ion batteries are expected to offer several advantages over traditional, nonaqueous liquid electrolytes. A solid electrolyte would give a longer shelf life, along with an enhancement in specific energy density. A solid electrolyte may also eliminate the need for a distinct separator material, such as the polypropylene or polyethylene microporous separators commonly used in contemporary liquid electrolyte-based batteries. Solid electrolytes are also desirable over liquid electrolytes in certain specialty applications where bulk lithium-ion batteries as weU as thin-film lithium-ion batteries are needed for primary and backup power supplies for systems, devices, and individual integrated circuit chips. 

Ethers, such as tetrahydrofuran and 1,2-dimethoxyethane, have low dielectric constants (7.4 and 7.2, respectively), and the choice of supporting electrolyte is very limited. The ethers are difficult to reduce and are inert toward many metalorganic reagents [243] that are soluble in the ethers. Ethers are thus suitable as medium for the anodic addition of Grignard reagents to olefins [420]. Dimethoxyethane and polyethylene glycol dimethyl ethers have the ability to solvate electrons [421]. Dissociation constants for some acids and the relative strength of some bases in THE has been determined [422]. 

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