Lithium-polymer

These electrodes have been evaluated in lithium-polymer cells that operate at 85 °C [35]. Although the electrochemical discharge is not yet fully understood, differential capacity plots have shown evidence of two reversible ordering transitions and a kinetically slow phase transformation. 

During the 1990s, lithium polymer cells have been scaled up to a size of 10 Wh, and assessment of their performance of continues. Test cells show a 1000-fold scale-up to have little effect on cell cycling... 

In battery applications, new hthium ion batteries called lithium ion polymer batteries (or more simply but misleadingly, lithium polymer batteries) work with a full matrix of ionically conducting polymer, this polymer being present inside the porous electrodes and as a separator between the electrodes. They are offered in attractive flat shapes for mobile applications (mobile phones, notebooks). 

E—Lithium Lithium anode Iodine, sulfur dioxide, thionyl chloride, and iron disulfide Secondary Lithium-iron disulfide batteries, lithium-ion batteries, and lithium polymer batteries... 

Lithium oxide(s), 15 134, 141 Lithium perchlorate, 3 417 15 141-142 dessicant, 3 360 in lithium cells, 3 459 Lithium peroxide, 15 142 18 393 Lithium phosphate, 15 142 Lithium-polymer cells, 3 551 in development, 3 43 It Lithium primary cells, 3 459-466 Lithium production, 9 640 Lithium products, sales of, 15 121 Lithium salts, 15 135-136, 142 Lithium secondary cells, 3 549-551 ambient temperature, 3 541-549 economic aspects, 3 551-552 high temperature, 3 549-551 Lithium silicate glass-ceramics, 12 631-632... 

However, some of the basic problems of polypyrrole and of the other heterocyclic polymers act to limit the performance of the lithium/polymer battery, and thus its wide applicability. These are essentially slow kinetics, self-discharge and low energy content. 

Although the diffusion of the counterion is faster in polypyrrole than in polyacetylene, its value is still low enough to influence the rate of the electrochemical charge and discharge processes of lithium/polymer batteries. Indeed the current output of these batteries is generally confined to a few mA cm . Possibly, improvements in the electrode kinetics, and thus in the battery rates, may be obtained by the replacement of standard ... 

The majority of polymer electrodes cannot be doped to very high levels. For instance, polypyrrole may reach doping levels of the order of 33%. This inherent limitation combined with the fact that the operation of the lithium/polymer battery requires an excess of electrolyte (to ensure... 

More recently, solid state batteries with lithium conducting polymer electrolytes have been extensively studied. The development has focused on secondary batteries for an electric vehicle, because lithium polymer batteries have a theoretical energy density that approaches 800 W h kg ... 

Fig. 11.14 Lithium polymer electrolyte cell configuration (Linford, 1991).

The potential use of polymeric ion-exchange membranes in the next generation single-ion secondary lithium polymer batteries was shown by Sachan et al 84,85 Conductivities exceeding 10 S/cm with transference numbers of unity were achieved for Nafion converted to the Li+ salt form. 

Lithium polymer electrolytes formed by dissolving a lithium salt LiX (where X is preferably a large soft anion) in poly(ethylene oxide) PEO can find useful application as separators in lithium rechargeable polymer batteries.Thin films must be used due to the relatively high ionic resistivity of these polymers. For example, the lithium-ion conductivity of PEO—Li salt complexes at 100 °C is still only about Viooth the conductivity of a typical aqueous solution. 

Lithium polymer batteries are similar in principle to the lithium batteries described above but the electrolyte is a polymer. The advantage of these batteries is the absence of liquid in the cell and so the batteries do not leak. The polymer electrolyte is a polymer-alkali metal salt complex. The best known such electrolytes are complexes of poly (ethylene) oxide (PEO). 

In lithium polymer batteries, one electrode is lithium foil, or in some cases another electrically conducting material such as graphite, and the other is a reversible intercalation compound as in liquid electrolyte lithium batteries. Compounds used as intercalation electrodes include LiCo02 and VeOis. The cell developed in the Anglo-Danish project, which ran from 1979 to 1995, was... 

Currently, several companies market lithium polymer batteries for use in, for example, phones. 

The mixed acetal groups are stable to both organo-lithium reagents and living lithium polymers. Such initiators are preparable in high yields (84—92%) and are soluble in diethyl ether or benzene and insoluble... 

A practical use of a microelectrode The advantages of microelectrode techniques are especially pronounced for systems with limited conductivity (e.g., polymer electrolytes), which are popular candidates for state-of-the-art lithium ion batteries, normally with room-temperature conductivities K - 10-4 S/cm. (a) A researcher is evaluating a newly synthesized lithium polymer electrolyte. He uses a two-electrode cell in which an electrolyte disk of 0.1 cm X 1.0 cm is... 

Because of the importance of high-performance secondary batteries, the techniques of the secondary lithium batteries are still making rapid progresses. Lithium polymer secondary batteries, having gel-polymer electrolytes, are advantageous in that the rigid metal container is not essential. Thus, all-plastic thin lithium secondary batteries are now available. 

It is perhaps useful to mention that the use of electronically conducting polymers, such as poly(acetylene), (CH) poly(pyrrole), (C4H5N)X, and poly(aniline), (CeHgNf ), has been proposed for positives for lithium batteries. The electrochemical process of these lithium-polymer positives is somewhat similar to an intercalation reaction. On charging, the polymer (P) is oxidized by acquiring a positive charge to form a polaron, and this is... 

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. 

Fig. 7.21 Schematic illustration of the construction of a lithium polymer battery (LPB)...

Scale-up from laboratory test cells to EV module is the next challenge for the LPB technology. There are three general areas which need to be addressed when considering scale-up, namely (1) raw materials, (2) component fabrication, and (3) cell and battery construction. In general, the raw materials employed in the various forms of lithium polymer batteries can easily be obtained in large quantities. The key areas are the lithium metal foil and the active positive material. Lithium metal foils are commercially available in a range of thicknesses down to 50 pm. However, thinner... 

LPB (lithium polymer battery) A cell (generally rechargeable) having a lithium foil negative, a metal oxide positive and a polymer electrolyte. 

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