Cell lithium alloys

Coin and Button Cell Commercial Systems. Initial commercialization of rechargeable lithium technology has been through the introduction of coin or button cells. The eadiest of these systems was the Li—C system commercialized by Matsushita Electric Industries (MEI) in 1985 (26,27). The negative electrode consists of a lithium alloy and the positive electrode consists of activated carbon [7440-44-0J, carbon black, and binder. The discharge curve is not flat, but rather slopes from about 3 V to 1.5 V in a manner similar to a capacitor. Use of lithium alloy circumvents problems with cycle life, dendrite formation, and safety. However, the system suffers from generally low energy density. 

Whereas there had been a significant amount of work on the properties of lithium alloys in the research community for a number of years, this alternative did not receive much attention in the commercial world until about 1990, when Sony began producing batteries with lithium-carbon negative electrodes. Since then, there has been a large amount of work on the preparation, structure, and properties of various carbons in lithium cells. 

The first use of lithium alloys as negative electrodes in commercial batteries to operate at ambient temperatures was the employment of Wood s metal alloys in lithium-conducting button-type cells by Matsushita in Japan. Development work on the use of these alloys started in 1983 [10], and they became commercially available somewhat later. 

The recent development of the convertible oxide materials at Fuji Photo Film Co. will surely cause much more attention to be given to alternative lithium alloy negative electrode materials in the near future from both scientific and technological standpoints. This work has shown that it may pay not only to consider different known materials, but also to think about various strategies that might be used to form attractive materials in situ inside the electrochemical cell. 

The physical properties of lithium metal were given in Table 4.4. Despite its obvious attractions as an electrode material, there are severe practical problems associated with its use in liquid form at high temperatures. These are mainly related to the corrosion of supporting materials and containers, pressure build-up and the consequent safety implications. Such difficulties were experienced in the early development of lithium high temperature cells and led to the replacement of pure lithium by lithium alloys, which despite their lower thermodynamic potential remained solid at the temperature of operation and were thus much easier to use. 

As with all high temperature batteries, the materials problem in the lithium alloy-metal sulphide system is one of trying to develop low cost components which are able to withstand the hostile environment of the cell. The choice of insulators and separators is greatly restricted by the high stability of Li20 which excludes use of the common ceramics such as Al203 and... 

Lithium-Aluminum/Metal Sulftde Batteries. The use of high temperature lithium cells for electric vehicle applications has been under development since die 1970s. Advances in Hie development of lithium alloy-tuelal sulfide batteries have led to the Li Al/FeS system, where the following cell reaction occurs,... 

The last type of reserve cell is the thermally activated cell, lhe older designs use calcium or magnesium anodes newer types use lithium alloys as anodes. 

Switching to lithium-alloy negative electrodes, some voltage loss must be noted. LiAl has Uu = -1-385 mV, Li4.5Pb has Uu = 388 mV. Entries 18-20 in Table 10(b) represent three examples of rechargeable cells, which have been, at least temporarily, commercialized. The first (No. 18) is due to a lithium alloy/carbon black battery conunercialized by the Matsushita Co. [248]. The lithium alloy components are Pb -I- Cd -I- Bi -h Sn (Wood s alloy). Button cells in the range 0.3 to 2.5 mAh were offered. The electrolyte was LiC104 in an unknown solvent. The practical energy densities, 2Wh/kg, were rather low. The c.b. positive electrode acts as a double... 

After this invention, research and development focused on the new carbonaceous anodes. Lithium alloys again attracted much attention in 1995, when Fuji Photo Film Celltech Co. (Japan) announced its Station lithium-ion cell, which... 

In 1994, Tadiran, an Israeli company, made the discovery described as follows This cell comprises as main components a negative electrode which is Lithium or Lithium alloy, a positive cathode which includes MnOa and an electrolyte which is 1,3-Dioxolane (148) with Lithium hexafluoroarsenate (LiAsFe) and a polymerization inhibitor [143]. 

After a 12-year research work on electroacoustic materials, I resumed investigating novel electrochemical cells. My efforts were focused on cells utilizing nonaqueous electrolytes, especially those with carbon/lithium alloy anodes. The result was a high-performance cell with LiCo02 (LCO) cathodes and lithiated carbon anodes. We named this battery system LIB. 

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