Plasticizers highly conductive polymer electrolyte

High conductivity but a complete lack of dimensional stability is not a recipe for success. The viscosity of some completely amorphous, high conductivity polymer electrolyte materials including MEEP and certain early, over-plasticized PEO-based systems, is too low for the electrolyte to remain in position. 

A plasticized electrolyte, usually obtained by the addition of small amounts of a liquid of high dielectric constant to a solving polymer electrolyte in order to enhance its conductivity. 

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. 

The solid polymer electrolyte is a solid plastic material which has ion exchange characteristics that make it highly conductive to hydrogen ions. The particular material that is used for the current electrolysis cells is an analogue of TFE teflon to which sulfonic acid groups have been linked. This plastic sheet is the only electrolyte required, there are no free acidic or caustic liquids, and the only liquid used in the system is distilled water. 

The ion conductivity of the three PEO/PMMA blend compositions, 25/75, 50/50, and 75/25 studied by us increases with ascending LiClO content due to increasing number of free mobile ions as shown in Figure 28. In addition, blend composition with 75 wt% PEO doped with 0 to 12 wt% LiClO displays comparatively higher a values in the order of 10 S cm than the other two blends. Nevertheless, Tan and Johan, (2011) studied the ion conductivity of PEO/PMMA blend polymer electrolyte found that the composition 20 wt% PEO and 80 wt% PMMA is the most miscible proportion for the blend. Figure 28 depicts that the PEO/PMMA 20/80 blend achieves a maximum ion conductivity of 7 x 10 S cm at 10 wt% LiClO, further enhancement in conductivity can be achieved by the addition of a low molecular weight, low viscosity, and high dielectric constant plasticizer, EC. The incorporation of EC facilitates the dissociation of the... 

Recently, dry-type polymer electrolyte having high ionic conductivity has been obtained by introducing branched short-chain polyethyleneoxide. In this system the branched chain acts as an internal plasticizer. Such a polymer shows high ionic conductivity of 10 S/cm at ca. 30°C. ... 

Lithium ion polymer batteries and laminated solid-state redox supercapacitors have also been fabricated [271]. In these plastic power sources, a highly conducting gel-type membrane electrolyte is placed between a PP-PANI electrode combination. 

Partly because of the crystallinity problem, the room-temperature conductivity of polymer electrolytes in which the only polymer component is PEO is too low for high current- and power-density applications such as vehicle power sources. The conductivity can be raised to about 10" Scm" at 25°C by use of plasticizers or irradiation cross-linking as described above but this is still insufficient for many purposes. 

For battery applications, high conductivity of the electrolyte must be complemented by good mechanical strength. Composite electrolytes derived from a rigid polymer and a fluid polymer host and, plasticized by high permittivity organic solvents, often have both the mechanical strength and conductivity necessary for the fabrication of room temperature batteries. 

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