Negative active material for lithium secondary battery and lithium secondary battery using the same

Abstract

A negative active material for a lithium secondary battery which is capable of improving packing density and has good high-rate charge/discharge and cycle life characteristics is provided. The negative active material includes a crystalline carbon core and an amorphous carbon shell. Alternatively, the negative active material includes secondary particles prepared by gathering at least one crystalline carbon primary particle. A surface of the secondary particles is coated with an amorphous carbon and the secondary particles has a substantially spherical form. The negative active material has two exothermic peak of the differential thermal analysis at 1000° C. or less. A lithium secondary battery using the negative active material can use propylene carbonate for an organic solvent of an electrolyte.