NOVELTY - The negative electrode active-material comprises composite powder containing particles of carbonaceous material and lithium ion-interstitially diffusible/releasable particles selected from metal and metal oxide particles capable of enhancing lithium ion interstitial diffusibility/releasability to/from carbonaceous material between the positive and negative electrodes when charged/discharged.    USE - The battery is used in notebook-type personal computers, notebook-type word processors, palm-top personal computers, portable telephones, portable printers etc..    ADVANTAGE - The battery has a higher voltage, a higher energy density, a higher charging/discharging capacity, a longer life cycle as well as improved safety.    DETAILED DESCRIPTION - A lithium secondary battery comprises a positive electrode (13) a negative electrode (16) containing a lithium ion-storable/dischargeable negative electrode material and a lithium ion-conductive, non-aqueous electrolytic solution or polymer electrolyte. The negative electrode material comprises a composite powder containing particles of carbonaceous material and lithium ion-interstitially diffusible/releasable particles selected from at least one of metal particles or metal oxide particles capable of enhancing lithium ion interstitial diffusibility/releasability to/from the carbonaceous material between the positive and negative electrodes when charged/discharged. At least 50 wt.% of the interstitially diffusible/releasable particles are embedded in the carbonaceous material particles. At least 90 wt.% of the composite powder has a particle size not more than 50 microns.    INDEPENDENT CLAIMS are also included for the following:    (A) A lithium secondary battery comprising a positive electrode, a negative electrode containing a lithium ion-storable/dischargeable negative electrode material and a lithium ion-conductive, non-aqueous electrolytic solution or polymer electrolyte. The negative electrode material comprises a composite powder containing particles of carbonaceous material and lithium ion-interstitially diffusible/releasable particles selected from at least one of metal particles or metal oxide particles capable of enhancing lithium ion interstitial diffusibility/releasability to/from the carbonaceous material between the positive and negative electrodes when charged/discharged. At least 50 wt.% of the interstitially diffusible/releasable particles are embedded in the carbonaceous material particles. The interstitially diffusible/releasable particles have an average particle size of 5 microns and at 90 wt.% of the particles have a particle size not more than 10 microns.    (B) A lithium secondary battery comprising a positive electrode, a negative electrode containing a lithium ion-storable/dischargeable negative electrode material and a lithium ion-conductive, non-aqueous electrolytic solution or polymer electrolyte. The negative electrode active material comprises a composite powder containing graphite particles and lithium ion-interstitially diffusible/releasable particles selected from at least one of metal particles or metal oxide particles capable of enhancing lithium ion interstitial diffusibility/releasability to/from the graphite between the positive and negative electrodes when charged/discharged. The interstitially diffusible/releasable particles are embedded in the graphite particles, and the graphite particles comprises not less than 80 wt.% hexagonal crystals and not more than 20 wt.% rhombohedral crystals.    (C) A lithium secondary battery comprising a positive electrode, a negative electrode containing a lithium ion-storable/dischargeable negative electrode material and a lithium ion-conductive, non-aqueous electrolytic solution or polymer electrolyte. The negative electrode material comprises oxide particles containing at least one element selected from silicon, tin, germanium, aluminum, zinc, bismuth and magnesium which are embedded in carbonaceous material particles.    (D) Methods for producing the above batteries.    DESCRIPTION OF DRAWING(S) - The diagram shows a cross-sectional schematic view of a lithium secondary battery.    Positive electrode current collector (11)    Positive electrode mix (12)    Positive electrode (13)    Negative electrode current collector (14)    Negative electrode mix (15)    Negative electrode (16)    Separator (17)    Positive electrode tab (18)    Negative electrode tab (19)    Battery can (20)    Battery lid (21)    Isolating gasket (22)    Insulating plate (23)