Abstract: 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 ?m, 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 ?m 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.

Abstract: This invention discloses a type of improved graphite granules and the method for their fabrication. Each improved graphite granule includes an unimproved graphite granule whose electrochemical properties need to be improved, and a membrane of amorphous carbon enveloping said unimproved graphite granule forming the membrane. The thickness of said amorphous carbon membrane is between 0.05 &mgr;m and 1 &mgr;m. To fabricate said improved graphite granules, said unimproved graphite granules are immersed in a polymer surface modifying solution, stirred, separated, sifted, and then solidified and carbonized. Said improved graphite granules, when used as the negative electrode of a lithium ion rechargeable battery produces a battery with excellent high current characteristics, high reversible specific capacity, long cycle life, and can satisfy the performance demands on rechargeable batteries. The technology for the fabrication of this improved graphite granules is simple. Its cost of production is low.

Abstract: 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 &mgr;m, 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 &mgr;m 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.

Abstract: This invention relates to a method for the fabrication of improved graphite granules from unimproved graphite granules, where a polymer solution is uniformly sprayed onto a fluidized bed of unimproved graphite granules that are being stirred three dimensionally in high speed. The granules are then heat to dry to obtain coated graphite granules. To further improve the electrochemical properties of the final improved graphite granules, the coated graphite granules are immersed in a surface modifier, filtered, heat to dry and sifted. Then, they are solidified and carbonized in an inert environment to obtain final improved graphite granules. This invention is simple, easy to implement, and easy to implement for industrial production. The improved graphite granules made using embodiments of this invention, when used as the material for the negative electrode of a rechargeable battery produces a battery that has high initial charge/discharge efficiency, high reversible specific capacity and good cycle ability.