Patent attributes
This invention relates to a negative electrode of a rechargeable battery. In particular, the active material for the negative electrode is a mixture of two types of graphite, graphite A and graphite B. Graphite A are of graphite granules having an average granule diameter between 10 and 40 μm, and a crystallite interlayer spacing, d002, between 0.335 and 0.342 nm. Graphite B are graphite granules with an average granule diameter between 5 and 30 μm and a crystallite interlayer spacing, d002, between 0.336 and 0.360 nm. The ratio of the weight of the graphite A and graphite B is between 25:75 to 80:20. To fabricate said negative electrode, take said mixture of graphite A and graphite B, add binder, dispersant, and solvent. Then stir to mix, coating the resultant mixture on a foil, heat to dry, and compress to form the negative electrode. A lithium ion rechargeable battery made with said negative electrode has high discharge capacity, long cycle life, excellent high current and safety characteristics. The manufacturing process for this negative electrode is simple and cheap and therefore, it is easy to implement for mass production.
