Compound Batteries

In some batteries two different types of electrodes are used on one side a conventional battery electrode with solid reactant and reaction products, and on the other side an electrode with gaseous and/or liquid reactant and products of the type used in fuel cells. Such batteries are called compound batteries or sometimes semi fuel cells (this term is rather poor). 

The most important group of compound batteries are metal-air batteries in which readily oxidized metals are used as anodes and so-called air-breathing electrodes are employed as cathodes. The cathode reactant—air oxygen—is readily available everywhere and need not to be stored in the battery, thus, providing a considerable economy in the battery mass and volume and a corresponding increase of the specific ampere-hour capacity 

The best-known example of a metal-air battery is the miniature button-type zinc-air battery widely used in hearing aids and other electronic devices of small size. Metallic zinc is the negative electrode in these batteries (usually in the form of highly disperse powder). When current is drawn, the zinc dissolves anodically in a concentrated alkaline solution according to the equation  

Electrodes built according to the principles of the oxygen (air) electrodes of alkaline fuel cells are used as the positive electrode in these batteries  

When the supply of metallic zinc is used up, the zinc-air battery stops working and cannot be reanimated. Repeated attempts have been made to build rechargeable zinc-air storage batteries. The reactions reported above are basically reversible, that is, can also occur in the opposite (charging) direction. For a number of reasons associated, both with the zinc and with the air electrodes, such rechargeable zinc-air batteries are as yet very unreliable and have so far not found any practical application, but research work in this direction continues. 

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Activity in the battery area using electronically conducting polymers has been intense (see Fig. 11.19). The possibilities (MacDiarmid, 1997) point to the provision of cheap (because of the relative cheapness of organic compounds) batteries, e.g., for massive use as a power source for bicycles. The counter-point is the limited stability and hence lifetime of such structures, and the availability of, e.g., rechargeable MnOj-Li cells, in which the (bismuth doped) Mn02 is also a relatively cheap material. 

Apidra) [7,8] analogue studies 12 month (rat) 6 month (dog) chronic study was designed to investigate the carcinogenic potential of the compound battery EMEA-2004... 

The definition of fuel cells is similar to the definition of batteries, but an important distinction is that in fuel cells the chemical reaction takes place between gaseous liquid and/or liquid reactants. The definition of compound batteries is also similar to that of batteries, the only difference being that in compound batteries the chemical reaction takes place between a solid reactant on one of the electrodes and a gaseous and/or liquid reactant on the other electrodes. 

Chemical compounds can also be represented by chemical data, or even by biological data. In fact, Briem et al. have used the results of a battery of biological assays to represent a compound for the modeling of other biological data [62-64]. 

The metallic salts of trifluoromethanesulfonic acid can be prepared by reaction of the acid with the corresponding hydroxide or carbonate or by reaction of sulfonyl fluoride with the corresponding hydroxide. The salts are hydroscopic but can be dehydrated at 100°C under vacuum. The sodium salt has a melting point of 248°C and decomposes at 425°C. The lithium salt of trifluoromethanesulfonic acid [33454-82-9] CF SO Li, commonly called lithium triflate, is used as a battery electrolyte in primary lithium batteries because solutions of it exhibit high electrical conductivity, and because of the compound s low toxicity and excellent chemical stabiUty. It melts at 423°C and decomposes at 430°C. It is quite soluble in polar organic solvents and water. Table 2 shows the electrical conductivities of lithium triflate in comparison with other lithium electrolytes which are much more toxic (24). 

The lead-bearing components ate released from the case and other nordead-containing parts, followed by the smelting of the battery plates, and refinement to pure lead or specification alloys. The trend toward battery grid alloys having Httle or no antimony, increases the abiHty of a recovery process to produce soft lead (refined). As requited in the production of primary lead, each step in the secondary operations must meet the environmental standards for lead concentration in ait (see Air pollution Lead compounds, industrial toxicology). 

Rea.ctivity ofLea.d—Ca.lcium Alloys. Precise control of the calcium content is required to control the grain stmcture, corrosion resistance, and mechanical properties of lead—calcium alloys. Calcium reacts readily with air and other elements such as antimony, arsenic, and sulfur to produce oxides or intermetaUic compounds (see Calciumand calciumalloys). In these reactions, calcium is lost and suspended soHds reduce fluidity and castibiUty. The very thin grids that are required for automotive batteries are difficult to cast from lead—calcium alloys. 

The lead storage battery, the largest single user of lead and its compounds, is made possible by the high degree of reversibiUty, both chemical and physical, in the fundamental chemical reaction... 

Most uses of lead in chemical compounds other than in storage batteries are dissipative. The greater part of the lead used in other forms is recoverable. 

Uses. The largest use of lithium metal is in the production of organometaUic alkyl and aryl lithium compounds by reactions of lithium dispersions with the corresponding organohaHdes. Lithium metal is also used in organic syntheses for preparations of alkoxides and organosilanes, as weU as for reductions. Other uses for the metal include fabricated lithium battery components and manufacture of lithium alloys. It is also used for production of lithium hydride and lithium nitride. 

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