Ion conductive polymers

The first use of ionic liquids in free radical addition polymerization was as an extension to the doping of polymers with simple electrolytes for the preparation of ion-conducting polymers. Several groups have prepared polymers suitable for doping with ambient-temperature ionic liquids, with the aim of producing polymer electrolytes of high ionic conductance. Many of the prepared polymers are related to the ionic liquids employed for example, poly(l-butyl-4-vinylpyridinium bromide) and poly(l-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide [38 1]. 

Another example of ion conducting polymer/ion/solvent systems are polyelectrolytes based on ion-exchange polymers, also called ionomers. The ionic conductivity of ion-exchange polymers is usually very low in the dry state, but increases abruptly by orders of magnitude upon addition of a... 

Ion-exchanger membranes with fixed ion-exchanger sites contain ion conductive polymers (ionomers) the properties of which have already been described on p. 128. These membranes are either homogeneous, consisting only of a polyelectrolyte that may be chemically bonded to an un-ionized polymer matrix, and heterogeneous, where the grains of polyelectrolyte are incorporated into an un-ionized polymer membrane. The electrochemical behaviour of these two groups does not differ substantially. 

As described in previous sections (Sections VI and VII), macromolecular design of polymer/salt hybrids with a highly dissociable lithium borate unit proved to be a valuable approach for single-ion conductive polymers. To further improve the degree of lithium salt dissociation, we have designed a polymer/salt hybrid bearing the boron-stabilized imidoanion (BSI)38 (Fig. 10). 

Note 4 A polymer that shows electric conductivity due to the transport of ionic species is called an ion-conducting polymer an example is sulfonated polyaniline. When the transported ionic species is a proton as, e.g., in the case of fuel cells, it is called a protonconducting polymer. 

Note 3 A polymer acid or a polymer base can be used as a matrix for ion-conducting polymers. 

The EDLCs, which use all-solid-state ion-conducting polymer [e.g., polyethylene oxide)/LiC104] or polymer gel electrolyte, have also been developed [3],... 

The lithium polymer battery (LPB), shown schematically in Fig. 7.21, is an all-solid-state system which in its most common form combines a lithium ion conducting polymer separator with two lithium-reversible electrodes. The key component of these LPBs is the polymer electrolyte and extensive work has been devoted to its development. A polymer electrolyte should have (1) a high ionic conductivity (2) a lithium ion transport number approaching unity (to avoid concentration polarization) (3) negligible electronic conductivity (4) high chemical and electrochemical stability with respect to the electrode materials (5) good mechanical stability (6) low cost and (7) a benign chemical composition. 

In the case of ion conductive polymers, gel polymer electrolytes which consist of a polymer matrix, organic solvents and supporting electrolyte, were introduced as novel nonaqueous electrolyte systems in electrochemical applications, such as rechargeable batteries and electric double layer capacitors [3-5], Recently, considerable attention has been devoted to the application of gel poly-... 

Ion-conducting polymer double layer elec- PAN gel electrolyte... 

Ion conducting polymers may be preferable in these devices electrolytes because of their flexibility, moldability, easy fabrication and chemical stability (for the same reasons that they have been applied to lithium secondary batteries [19,48,49]). The gel electrolyte systems, which consist of a polymeric matrix, organic solvent (plasticizer) and supporting electrolyte, show high ionic conductivity about 10 5 S cnr1 at ambient temperature and have sufficient mechanical strength [5,7,50,51], Therefore, the gel electrolyte systems are superior to solid polymer electrolytes and organic solvent-based electrolytes as batteries and capacitor materials for ambient temperature operation. 

C. All-Solid-State EDLC with Ion Conducting Polymer... 

In the past five years, many ion conducting polymers and gel electrolytes have been investigated for EDLC application. Figure 15 shows the capacities of various carbon electrodes in SPE or gel electrolytes. The values listed in this figure do not satisfy the requirements for EV. However, it is expected that the requirements of supercapacitors for EV can be achieved by development of devices based on composite electrodes and gel electrolyte systems as described in this chapter. 

Ion pairing is exceedingly the case in ion-conducting polymers. Polar functional groups enable a partial dissociation of the dissolved salt molecules 73 according to... 

Oxide admixtures also proved beneficial (see, e.g. reference116) in the case of ion conducting polymers. Even though mobility effects occur, too, the separation of an ion pair in the rather covalent matrix by adsorbing one partner is possible, an effect that can be subsumed under the phenomenon of heterogeneous doping.37... 

Polyglycidol containing cyanoethyl, (III), trimethylsilylacetyl, and cyanoben-zoyl termini were prepared by Sata [3] and used as a component in ion-conductive polymer electrolyte compositions. 

In some fields solid (or film) electrolytes are preferred to the liquid electrolytes. This is especially the case in industrial applications. Accordingly gel-type ion conductive polymers are prepared by mixing AMILs with several polymers. AMILs having Li can be mixed with a host of polymers, as shown in Scheme 21.2, to... 

Ambient temperature molten salt can be obtained by several methods. One effective way to obtain a room-temperature molten salt is by the introduction of polyether chains to ions. The term polyether/salt hybrid is used in this chapter as a common name for polyether oligomers having anionic or cationic charge(s) on the chain (Figure 22.1). Polyethers, such as poly-(ethylene oxide) (PEO), are known as representative ion conductive polymers [1]. Polyether/salt hybrids have been studied as a kind of room-temperature molten salt apart from the development of onium-type ionic liquids [2]. The preparation of ionic liquids consisting of metal ions has been one of the important goals in this research field. Polyether/salt hybrid derivatives give one such solution for this task. 

In this chapter, we report on the ion conductive behavior of new ion conductive polymers that polymerize the IL itself. 

Ogihara W, Washiro S, Nakajima H, et al. Effect of cation stracmre on the electrochemical and thermal properties of ion conductive polymers obtained from polymerizable ionic hquids. Electrochim. Acta. 2006. 51, 2614-2619. 

Yoshio M, Kagata T, Hoshino K et al (2006) One-dimensiontil ion-conductive polymer films alignment and fixation of ionic channels formed by self-organization of polymerizable columnar liquid crystals. J Am Chem Soc 128 5570-5577... 

---