Negative electrode materials electrochemical performance

An Li-Al Alloy was investigated for use as a negative electrode material for lithium secondary batteries. Figure 41 shows the cycle performance of a Li-Al electrode at 6% depth of discharge (DOD). The Li-Al alloy was prepared by an electrochemical method. The life of this electrode was only 250 cycles, and the Li-Al alloy was not adequate as a negative material for a practical lithium battery. 

Fullerenes do not exhibit good electrochemical performance as negative electrode materials for lithium-ion batteries, although some lithium can be reversibly stored therein. Therefore, they will not be discussed here. 

Electrochemical Performance of Graphite as Negative Electrode Material... 

Natural graphite can be used as a negative electrode material. At low temperatures such as -20°C, its electrochemical performance is not good, which is mainly ascribed to the slow diffusion kinetics of Li+ ions, and not to the low ionic conductivity of electrolyte and the SEI film. It has also been stated that the main reason for the weak performance is the porosity, i.e., the low number of Lh ions that can intercalate into graphite since it is known that an increase in porosity can improve the rate capability of natural graphite. 

Other metals can also form compounds X-C or Li-X-C (X includes Zn, Ag, Mg, Cd, In, Pb, and Sn), which can be used as negative electrode materials for lithium-ion batteries. There is an evident improvement in the electrochemical performance, mainly because the introduced metals favor Li diffusion. Other kinds or two or more types of heteroatoms can also be introduced. 

Other polymers having no electroactivity (for example, polyelectrolytes like gelatine and cellulose) can modify the electrochemical performance of carbon negative electrode materials, with the following favorable effects ... 

Different changes in structure have been observed in accordance with different ways and conditions of milling. As a result, the electrochemical performance of these negative electrode materials also varies greatly. 

As mentioned above, carbon negative electrode materials manufactured from nongraphitic carbon also display structural changes after milling. As a result, the electrochemical performance will also change. Petroleum cokes prepared by milling for 12-24 h with an average particle size of 6-8 pm show the best electrochemical characterishcs. 

Electrochemical Performance of Some Carbon Products as Negative Electrode Materials for Lithium-Ion Batteries... 

Similar to Sn, oxides such as PbO and Pb02 can also be used as negative electrode materials for lithium-ion batteries based on an alloy-type mechanism. It is also possible to improve their electrochemical performance by modification. 

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