Polymer electrolyte batteries

The early literature (until 1982) is summarized in Refs. [1] and [2], Hundreds of papers have been published since then (most of them in since 1994) and it is impossible to summarize all of them here. The Proceedings of the conferences mentioned above are good, sources of recent developments though sometimes incomplete. Since the early 1980s new systems have been introduced. The most important of these are lithium-ion batteries (which have lithiated carbonaceous anodes) and polymer-electrolyte batteries. Until 1991 very little was published on the Li/polymer-electrolyte interface [3, 4], The application of the SEI model to Li-PE batteries is ad-... 

It is now well established that in lithium batteries (including lithium-ion batteries) containing either liquid or polymer electrolytes, the anode is always covered by a passivating layer called the SEI. However, the chemical and electrochemical formation reactions and properties of this layer are as yet not well understood. In this section we discuss the electrode surface and SEI characterizations, film formation reactions (chemical and electrochemical), and other phenomena taking place at the lithium or lithium-alloy anode, and at the Li. C6 anode/electrolyte interface in both liquid and polymer-electrolyte batteries. We focus on the lithium anode but the theoretical considerations are common to all alkali-metal anodes. We address also the initial electrochemical formation steps of the SEI, the role of the solvated-electron rate constant in the selection of SEI-building materials (precursors), and the correlation between SEI properties and battery quality and performance. 

The majority of electrochemical cells to have been constructed are based on PEO, PAN, or PVdF [101]. Recently, the Yuasa Corporation have commercialized solid polymer electrolyte batteries, primarily for use in devices such as smart cards, ID cards, etc. To date, the batteries which have been manufactured and marketed are primary lithium batteries based on a plasticized polymer electrolyte, but a similar secondary battery is expected [120]. 

Research and development into polymer electrolyte battery systems continues, yet many unsolved and controversial issues, particularly relating to the inadequate understanding and control of ion dissociation and the relative mobilities of the ions, remain. Modem computational resources now allow the structures of complex systems such as polymer electrolytes to be simulated and evaluated. Computer simu-... 

Since the realization in the early 1980s that poly (ethylene oxide) could serve as a lithium-ion conductor in lithium batteries, there has been continued interest in polymer electrolyte batteries. Conceptually, the electrolyte layer could be made very thin (5im ) and so provide higher energy density. Fauteux et al. [31] have recently reviewed the present state of polymer elec-... 

The last few years have witnessed a high level of activity pertaining to the research and development of all-solid, thin-film polymer electrolyte batteries most of these use lithium as the active anode material, polymer-based matrices as solid electrolytes, and insertion compounds as active cathode materials. High-performance prototypes of such batteries stand currently under research, whose trends are expected to include the development of amorphous polymers with very low glass-transition temperatures, mixed polymer electrolytes, and fast-ion conductors in which the cationic transport number approaches unity. 

Battery electrodes for aqueous [306a-g], non-aqueous [306h-p], ambient molten salt [306q], and all-solid state polymer electrolyte batteries [306r-t]. As long as the redox chemistry of a polymer is reversible and both oxidized and reduced forms of the polymer are not soluble in a solvent with which a battery is to be constructed, it can be used as a battery electrode material. Numerous applications have been published for PPy, PTh, and other conducting polymers as well. 

Polymer electrolyte batteries have been used in implanted cardiac pacemakers since 1972. The system used is lithium/iodine-polyvinylpyridine. Although the conductivity of the Li ions in Li2l is poor, the current requirements are very small, and the major consideration is the storage of a high energy density of nearly 1 Whcm . ... 

Figure I 2.1 I Construction of a polymer electrolyte battery (from Song, J. Y.,J. Power Sources, 77, 183, 1999) Elsevier.

Murata, K. Izuchi, S Yoshihisa, Y., An overview of the research and development of solid polymer electrolyte batteries, Electrochim. Acta 2000, 45, 1501-1508. 

Figure 6.29 Pictorial illustration of the model of the charging process in polymer electrolyte batteries. Part of the capacity is lost by shunt along dendrites and by electrical isolation of some intercalation compound particles. From [16] by permission of Elsevier Sequoia S.A.

Shin J-H, Henderson WA, Passerini S (2005) PEO-based polymer electrolytes with ionic liquids and their use in lithium metal-polymer electrolyte batteries. J Electrochem Soc 152(5) A978-A983. doi 10.1149/l.1890701... 

GOL 99] Golodnitsky D., Peled E., Pyrite as cathode insertion material in rechargeable Uthium/composite polymer electrolyte batteries , Electrochim. Acta, vol. 45, pp. 335-350, 1999. 

Momma, T., Kakuda, S., Yarimizu, H., and Osaka, T., Electrochemical redox properties of polypyrrole/Nafion composite film in a solid polymer electrolyte battery, J. Electrochem. Soc., 142, 1766-1769 (1995). 

The electrolyte can be fabricated in the form of a thin solid film, thereby eliminating the need of a separator element requirement. The very thin electrolyte, combined with a thin electrode structures, could allow electrode high rate performance and improved lithium everlasting morphology. The possibility of greater intrinsic safety combined with improved rate capability makes the polymer electrolyte battery system a viable candidate for a high-performance battery. Major advantages of polymer electrolyte batteries can be summarized as follows ... 

Unique Design Features of Polymer Electrolyte Batteries... 

In the late 1970s, polymer electrolyte materials were proposed for use in solid-state battery designs." A considerable development effort has resulted in a number of review arti-cles" " describing the status of such batteries in some detail. The unique aspect of these batteries is that the electrolyte is a soM flexible film comprised of a polymer matrix and an ionic salt complexed into the matrix. Thin-film solid-polymer electrolyte batteries offer tbe possibility of an intrinsically safe battery design in combination with good high-rate capability. 

Polyethylene oxide was the first material utilized as the matrix material. Initially, it was necessary to operate the cells at elevated temperatures (100°C) to obtain adequate conductivities (10 S/cm), but a variety of polymeric electrolytes that may be useful at normal ambient temperatures were subsequently developed. This polymer electrolyte battery is based on thin-film components that incorporate large area electrolyte and electrode layers. A general cell can be schematized as ... 

The first and the second categories, the latter of which (PVDF-based systems) does not properly belong to the class of polymer electrolyte batteries, are covered in Chap. 35. In this chapter, the attention is focused on the lithium metal, dry polymer electrolyte systems. 

Polymer Electrolyte Battery Using The design of another configuration of an SPE... 

The polymer Li-ion cells described here may be more accurately described as employing a gel electrolyte, as the electrolyte contains a monomeric, volatile liquid component absorbed into a polymeric host, in contrast to technologies which do not employ a volatile, liquid component, such as solid polymer electrolyte batteries. Because of the poor conductivity of currently available solid polymer electrolytes (solid polymer lithium batteries developed to date operate at 40°C to 80°C to accommodate the low conductivity of the electrolyte) (see Sec. 34.4.2), current polymer Li-ion batteries incorporate less viscous, liquid components to improve the conductivity of the electrolyte, enabling their use at ambient temperatures. 

D. Golodnitsky and E. Peled, Pyrite as Cathode Insertion Material in Rechaigeable Lithium/Composite Polymer Electrolyte Batteries, Electrochimica Acta, Vol. 45, 1999, p. 335. 

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