Negative secondary lithium-carbon batteries

In the lithium-ion secondary battery, which was put on the market in 1990, the difficulty of the Li+/Li electrode was avoided by use of a carbon negative electrode Cy), which works as a host for Li+ ions by intercalation. The active material for the positive electrode is typically LiCo02, which is layer-structured and also works as a host for Li+ ions. The electrolyte solutions are nearly the same as those used in the primary lithium batteries. A schematic diagram of a lithium-ion battery is shown in Fig. 12.2. The cell reaction is as follows ... 

This is a laboratory experiment. Carbon was studied as a half-ceU (section 2.2.3) with a metal lithium electrode as the counter electrode. The difference in voltage between these two electrodes is, naturally, very low. This is one of the reasons why carbon is often used as the negative electrode in hthium-ion secondary batteries instead of metal hthiiun, because it does not decrease the voltage of a cell too greatly. Such a decrease would lower the specific energy (defined in section 2.4.16.). It should be noted that in this half-ceU , carbon is a positive electrode because it is used in conjunction with lithium. 

V versus Lf/Li (case of a metal lithium negative electrode) or 4.18V versus C/LiCg (case of a lithiated carbon negative electrode in lithium-ion secondary batteries). 

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