Negative active material for lithium secondary battery, method for preparing the same, negative electrode comprising the same, and lithium secondary battery comprising same

A method of manufacturing a negative active material for a rechargeable lithium battery including preparing a first graphite particle formed by first particle precursors having flake-shaped graphite pieces being linked to one another forming a curved side, by exfoliating the flake-shaped graphite pieces, preparing a mixture by mixing the first particle precursors and at least one second particle selected from the group consisting of an element particle selected from the group consisting of Si, Sn, Al, Ge, Pb, and combinations thereof;

• an element compound particle selected from the group consisting of Si, Sn, Al, Ge, Pb, and combinations thereof;
• a composite particle comprising at least an element selected from the group consisting of Si, Sn, Al, Ge, Pb, and combinations thereof;
• a carbon composite particle comprising at least one element selected from the group consisting of Si, Sn, Al, Ge, Pb, and combinations thereof;
• and a combination particle thereof, and assembling the mixture, wherein the at least one second particle is dispersed between the flake-shaped graphite pieces inside the first graphite particle, and the first particle precursors are exfoliated to the flake-shaped graphite piece s in a thickness range of 0.01 μm to 0.1 μm.

A method of manufacturing a negative active material for a rechargeable lithium battery comprising preparing a first graphite particle formed by first particle precursors having flake-shaped graphite pieces being linked to one another forming a curved side, by exfoliating the flake-shaped graphite pieces, preparing a mixture by mixing the first particle precursors, at least one second particle selected from the group consisting of an element particle selected from the group consisting of Si, Sn, Al, Ge, Pb, and combinations thereof;

• an element compound particle selected from the group consisting of Si, Sn, Al, Ge, Pb, and combinations thereof;
• a composite particle comprising at least an element selected from the group consisting of Si, Sn, Al, Ge, Pb, and combinations thereof;
• a carbon composite particle comprising at least one element selected from the group consisting of Si, Sn, Al, Ge, Pb, and combinations thereof;
• and a combination particle thereof, and an amorphous carbon precursor or a soft carbon precursor, assembling the mixture to prepare an assembly in which the at least one second particle and the amorphous carbon precursor or soft carbon precursor are dispersed, and heat-treating the assembly to carbonize the amorphous carbon precursor or the carbon precursor, wherein the at least one second particle is dispersed between the flake-shaped graphite pieces inside the first graphite particle, and the first particle precursors are exfoliated to the flake-shaped graphite piece s in a thickness range of 0.01 μm to 0.1 μm.