Solid Polymer Electrolyte table

The different techniques which have been applied to determine transport in polymer electrolytes are listed in Table 6.1. For a fully dissociated salt all the techniques yield the same values of t (small differences may arise due to second order effects such as long range ion interactions or solvent movement which may influence the different techniques in different ways). In the case of associated electrolytes, any of the techniques within one of the three groups will respond similarly, but the values obtained from different groups will, in general, be different. Space does not permit a detailed discussion of each technique, this is available elsewhere (see Bruce and Vincent (1989) and the references cited therein). However, we will consider one technique from each group to illustrate the differences. A solid polymer electrolyte containing an associated uni-univalent salt is assumed. 

D - diffusion coeff., cm /sec. SPE - solid polymer electrolyte PEO - polyethylene oxide AN, THF and other solvents Table II. 

Two cases were examined for the production of water electrolysis. Data were taken from Reference (1) and adjusted to mid-1979 levels in accordance with Table 1. The costs of "current technology" electrolysis were averaged in Reference (1) from information provided by Lurgi, Electrolyser Corp., General Electric, and Teledyne Isotopes. An advanced electrolyzer design, based upon the General Electric Solid Polymer Electrolyte (SPE) design, was also addressed as the second case. 

Organic polydisulfides were combined with lithium metal in solid-polymer electrolytes [102-105] cf. No. 17 in Table 10 and Section 2. The cells were cycled at 80 °C. 

The development of solid polymer electrolyte cells is being actively conducted at General Electric Co. (13) and at Brown Boveri Research Center, Baden, Switzerland (14). As the name implies, the solid polymer electrolyte technology uses a solid polymer sheet as the sole electrolyte in the cells. It also acts as the cell separator. The majority of the present applications use Nafion with a thickness of 10-12 mils (13). Selected physical and chemical properties of Nafion 120 membranes are given in Table I. The membrane is equilibrated in water to approximately 30% water content prior to fabrication into a cell assembly. The hydrated membrane is highly conductive to hydrogen ions. It has excellent mechanical strength, and it is very stable in many corrosive cell environments. 

Ion exchange membranes have been used in various industrial fields, and have great potential for use in new fields due to their adaptable polymer membrane. As mentioned in the Introduction, membranes are characterized mainly by ion conductivity, hydrophilicity and the existence of carriers, which originate from the ion exchange groups of the membrane. Table 6.1 shows reported examples of applications of ion exchange membranes and the membrane species used in various fields. Various driving forces are usable for separation electrochemical potential, chemical potential, hydraulic pressure such as piezodialysis and pervaporation, temperature difference (thermo-osmosis), etc. Of these, the main applications of the membrane are to electrodialysis, diffusion dialysis, as a separator for electrolysis and a solid polymer electrolyte such as in fuel cells. 

An alternative to lithium batteries with liquid electrol5des are those with solid polymer electrolytes. Solid polymer electrodes are generally gel type electrolytes which trap solvent and salt in pores of the polymer to provide a medium for ionic conduction. Typical polymer electrolytes are shown in Table 15.8. 

Overall, much effort has been made to develop biocompatible organic materials, which allows for the ultimate integration between the electronic device and biological system. The possibility of fabricating memory devices on biodegradable substrates, such as, rice paper and chitosan is also demonstrated. Biocompatible and flexible resistive switching memory devices are made on the basis of Ag-doped chitosan as the natural solid polymer electrolyte layer on the transparent and bendable substrate. Decomposable devices, where chitosan layer serves as the substrate while Mg as the electrode, have been also achieved (Hosseini and Lee, 2015). A comparison of the biocompatible material-based resistive switching memory devices is made in Table 3.2. 

The similarity in the ionic transport mechanism in organic liquid electrolytes and solid polymer electrolytes is reflected in the ionic transport numbers measured in the two media. Table 3.5 lists the transport numbers for Li in LiC104 solutions in propylene carbonate (PC) and propylene carbonate/dimethoxy ethane (PC/DME) mixtures [26]. The t+ in PC/LiC104 is 0.28 which increases to between 0.40 and 0.50 with the addition of DME. This increase in t+ in PC/DME mixtures may reflect a change in the solvation characteristics of Li, and/or ionic species present, with the addition of DME. It is then possible that a range of cation transference numbers between 0.2 and 0.6 measured in polymer electrolytes is a reflection of the coordination properties of the particular polymer host with Li" and the nature of the ionic species present. 

Table 2. The results of solid-state Zn-air cells with PVA-PECH solid polymer electrolytes at C/10 discharge rate.

Table 8. The characteristic properties of different alkaline PVA-based solid polymer electrolytes and commercial non-woven PP/PE separator.

Gel and solid polymer electrolytes aim to combine the function of the electrolyte and separator into a single component to reduce the number of parts in an ES and increase the potential window through the higher stability offered by a polymer matrix. A gel electrolyte incorporates a liquid electrolyte into a microporous polymer matrix that holds in the liquid electrolyte through capillary forces, creating a solid polymer film. The chosen separator must be insoluble in the desired electrolyte and provide adequate ionic conductivity. Non-polar rigid polymers such as PTFE, PVA, PVdF, and cellulose acetate offer good ion conductivity when used as gel electrolytes [114]. Based on the data in Table 4.9, the ionic conductivity of EtMeIm+Bp4 is 14 mS.cm". Ionic conductivity of the same imidazolium salt used as a gel electrolyte in a PVdF matrix retains 5 mS.cm [115]. 

Solid state films that have been developed to utilize solid polymer electrolytes without requiring safety sealing and additional packaging. Patents claim that organosilicon compounds (U.S. Patent 20070076349) and polyoxy-alkylene-modified silanes (U.S. Patent 20070048621) are suitable with the additions of varying electrolyte salts (and separators if needed) for use as solid film electrolytes. Table 5.3 lists recent patents on electrolytes. 

Table 5A Typical pefforoaiaii of a solid polymer electrolyte cell...

This method is very popular for measuring transference numbers of lithium electrolytes (see references in Table 17.18) because of the very easy procedure and low time costs. But it must be taken into account that the measurement was developed for binary and ideal solid electrolytes, which is often not the case, especially for solid polymer electrolytes, where a large amount of ion-pairs is probable. 

The electrochemical behavior of the crystalline fullerene films is also influenced by the medium. Dissolution of the reduced films is quite important for the films doped with small cations in acetonitrile. It is significantly reduced for large tetraalkylammonium cations or especially so for the polypyridine complex metal cations in acetonitrile, probably because of relatively high polarizability of the aromatic ligands and fullerene anions in the latter case. The extent of dissolution is also a function of the extent of film reduction (see Table 7.9). For solid polymer electrolytes (see refs. [165,167]), the polymer may take part in the... 

Table 1.7 Properties of commercial cation exchange (adapted from Smitha eta ., 2005). Reprinted from J Membrane Sci, 259, Smitha B, Sridhar S and Khan AA, Solid polymer electrolyte membranes for fuel cell applications - a review, page 13, Copyright (2005), with permission from Elsevier...

Table 5.1. Some coordinating polymers which have been used as solid solvents for polymer electrolytes...

Lithium secondary batteries can be classified into three types, a liquid type battery using liquid electrolytes, a gel type battery using gel electrolytes mixed with polymer and liquid, and a solid type battery using polymer electrolytes. The types of separators used in different types of secondary lithium batteries are shown in Table 1. The liquid lithium-ion cell uses microporous polyolefin separators while the gel polymer lithium-ion cells either use a PVdF separator (e.g. PLION cells) or PVdF coated microporous polyolefin separators. The PLION cells use PVdF loaded with silica and plasticizer as separator. The microporous structure is formed by removing the plasticizer and then filling with liquid electrolyte. They are also characterized as plasticized electrolyte. In solid polymer lithium-ion cells, the solid electrolyte acts as both electrolyte and separator. 

TABLE XI. Some Solid-Polymers as Candidate SB Electrolytes... 

In polymer-based ISEs, electrical contact between the membrane and inner reference electrode is made via an inner filling electrolyte. This type of ISE is the most common and they are usually referred to as liquid contact ISEs or very often simply ISEs. On the other hand, the contact can be obtained by the substitution of the aqueous inner solution with another polymeric material, to produce so-called solid-contact ISEs Table 2.1 provides current achievements in trace level... 

Fuel cells are classified primarily according to the nature of the electrolyte. Moreover, the nature of the electrolyte governs the choices of the electrodes and the operation temperatures. Shown in table 10.1 are the fuel cell technologies currently under development. "" Technologies attracting attention toward development and commercialization include direct methanol (DMFC), polymer electrolyte membrane (PEMFC), solid-acid (SAFC), phosphoric acid (PAFC), alkaline (AFC), molten carbonate (MCFC), and solid-oxide (SOFC) fuel cells. This chapter is aimed at the solid-oxide fuel cells (SOFCs) and related electrolytes used for the fabrication of cells. 

Fuel cell-based power plants that have an output of up to 10 kW are under vigorous development as well, and they find ever wider practical uses. Table 24.3 shows the number of such plants produced every year from 2001 to 2010. Approximately half of the units produced in 2006 had a power of about 1 kW, and the other half had an output of 1.5-10 kW, the numbers being distributed evenly over this time interval. The overwhelming number (more than 50%) of these plants were produced and set up in Japan, with the United States taking the second place. Most of the low-power units were built with polymer electrolyte fuel cells. The fraction of solid oxide fuel cells has decreased gradually. 

The main features to keep in mind when distinguishing the ionic conductivity process in polymer electrolytes from that which occurs in either liquid or solid electrolytes are summarized in Table 1.1, and are now described in more detail. 

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