- Methods for manufacturing composite including Si Si-transition metal compound graphite and amorphous carbon anode material for secondary battery including composite manufactured thereby and Li-ion secondary battery comprising the same

摘要

The present invention relates to a method for preparing a composite of silicon/silicon-transition metal compound/graphite/amorphous carbon. The method according to the present invention comprises the steps of: (S1) preparing a composite of silicon/silicon-transition metal compound by applying mechanical energy to a mixture of silicon with a transition metal; (S2) preparing a composite of silicon/silicon-transition metal compound/graphite by applying mechanical energy to a mixture of the composite of silicon/silicon-transition metal compound with a graphite; and (S3) obtaining a composite of silicon/silicon-transition metal compound/graphite/amorphous carbon by mixing the composite of silicon/silicon-transition metal compound/graphite/amorphous carbon with an amorphous carbon-producing precursor in a solvent and carrying out pyrolysis. According to the present invention, it is possible to obtain a composite comprising silicon, silicon-transition metal compound, graphite and amorphous carbon by using mechanical synthesis and pyrolysis. In addition, when using the composite comprising silicon, silicon-transition metal compound, graphite and amorphous carbon as an electrode active material for a secondary battery, it is possible to realize a lithium secondary battery system, which can solve the problems of the conventional lithium alloy-based electrode materials for a lithium secondary battery, such as degradation of life caused by volumetric swelling, shows excellent initial efficiency while maintaining high capacity, and has high capacity and excellent cycle life.