Commercial rechargeable types

Table 1. Commercially available rechargeable coin-type cells with lithium-metal alloys...

Although primary batteries of various types based on Agl complexes are at present available commercially, no substantial success has been achieved with rechargeable SBs with Ag compounds conducting at ambient temperature (although Ag/complex/Ag coulometers capable of being cycled many thousands of times are readily available). After a decade of studies, cells based on Agl complexes have not yet been made which are rechargeable to any extent the complex tends to break down into islands of the y-Agl, which is very poorly conductive at room temperature. 

There have been a number of attempts to produce commercial lithium rechargeable batteries. The V205 positive is currently used by the Matsushita Battery Industrial Co in Japan for the production of small capacity, coin-type cells. Fig. 7.24 shows a cross-section of one prototype. For the construction of the battery, V205 and carbon black are mixed together with a binder, moulded and vacuum-dried to form the positive electrode pellet. A solution of LiBF4 in a propylene carbonate-y-butyrolactone-1,2-dimethoxyethane mixture absorbed in a polypropylene separator is used as the electrolyte. 

A wide variety of carbonaceous materials can intercalate or insert lithium reversibly and thus may be candidates for anodes for lithium ion batteries. In recent years, many types of carbons have been tested as alternative anodes for rechargeable lithium batteries, part of which have found use as anodes in practical, commercial lithium ion batteries. The most straightforward way of classifying these electrodes is according to the type of the carbon, which determines their capacity and basic electrochemical behavior. The major types of carbons tested in recent years as anode materials for Li ion batteries are listed below ... 

According to Pearson s Handbook, this crystal structure is commonly known as the CaCus-type structure. The parent LaNis alloy is well known for its unique hydrogen storage properties, and many closely related alloys with the same crystal structure have been commercialized as electrode materials in rechargeable nickel-metal hydride batteries. 

A traditional rechargeable lithium battery uses a Li anode, a solid cathode (e.g. thermally treated MnOa) and a non-aqueous solution based on a Li salt dissolved in aprotic solvents. Today, the only commercial batteries of this type are the small Li/Mn02 coin cells developed at Sanyo. Research on alternative batteries with sulphur cathodes (normally as organic sulphides) is in progress. 

Other types of batteries have been developed, but, with some notable exceptions, they have not yet reached commercial importance. Among these, we may mention flow batteries and high temperature solid state or fused salt batteries. Some of these batteries are rechargeable and some are suited for high capacity applications only. 

Today, most of the commercial electric vehicles operate with the lead acid battery, despite the efforts to develop newer types of rechargeable batteries. 

The energy density of the rechargeable lithium is the highest among commercial batteries and the selfdischarge is very low. There are several types of hthium batteries of interest the most promising chemistries are the Hthium-ion (Li-ion) and the hthium polymer (Li-polymer). 

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