Cycling 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. 

Nanostructured intermetallic alloys can also be used as active electrode materials in lithium-ion batteries. The benefit in this case is the addition of an inactive metal into the host metal, which helps to buffer the large strains on lithium alloying and thus improve reversibility. The improvement in cycling performance is accompanied by a sacrifice in... 

In the meantime, it was demonstrated that lithium can be reversibly inserted into graphite at room temperature in an organic electrolyte in 1983. Lithium-ion battery was first commercialized with this carbon-based anode in 1991. Graphite bas a capacity of 372 mAh/g, corresponding to the intercalation of one lithium atom per six carbon atoms. Though carbon bas ratber lower capacity than lithium metal and lithium alloy anodes, volume change was small and represented longer cycle performance. After this commercialization, many researchers and companies have put their effort on new carbonaceous anodes. 

Tracking the number of new technologies and ideas for the last two decades to overcome these two conflicting facts of capacity and cycle life on lithium alloy electrodes, it is inferred that lithium alloy electrodes only work with both macroscopic design of the whole electrode structure and microscopic nanotechnology at each interface. Much attention will be given further and effort will be made on lithium alloy systems for the next generation lithium battery. 

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