Carbonaceous material and lithium secondary batteries comprising same

A method of preparing a carbonaceous material comprising the steps of:

• calcining a Si particulate composed of a crystalline Si phase in a carbon crucible at 1300 to 1400° C. to deposit a SiO2 phase and a SiC phase in the crystalline Si phase;
• adding a conductive carbon material to the Si particulate;
• applying a polymer material coating solution to the Si particulate to provide a complex particle precursor;
• calcining the complex particle precursor to render the polymer material coating solution into a rigid carbon layer to provide a complex particle;
• adding the complex particle to a graphite particle;
• applying a polymer material coating solution to the graphite particle to provide a carbonaceous material precursor;
• and
• calcining the carbonaceous material precursor to render the polymer material coating solution into an amorphous carbon layer to provide a carbonaceous material.

A method of preparing a carbonaceous material comprising the steps of:

• calcining a Si particulate together with a B2O3 powder in a carbon crucible at 1300 to 1400° C. to deposit SiO2, SiC, and SiB4 phases in a crystalline Si phase;
• adding a conductive carbon material to the Si particulate;
• applying a polymer material coating solution to the Si particulate to provide a complex particle precursor;
• calcining the complex particle precursor to render the polymer material coating solution into a rigid carbon layer to provide a complex particle;
• adding the complex particle to a graphite particle;
• applying a polymer material coating solution to the graphite particle to provide a carbonaceous material precursor;
• and
• calcining the carbonaceous material precursor to render the polymer material coating solution into an amorphous carbon layer to provide a carbonaceous material.