NEGATIVE ACTIVE MATERIAL MANUFACTURING METHOD AND NEGATIVE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY NEGATIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

摘要

The present invention provides a manufacturing method of a cathode active material for a lithium secondary battery, a cathode active material for a lithium secondary battery, a cathode for a lithium secondary battery, and a lithium secondary battery including the same. The cathode active material for a lithium secondary battery comprises 45-60 atom% (excluding 60 atom%) of Si, 25-45 atom% of an added metal M, and 10-25 atom% of Fe. The added metal M includes one or more metal elements selected from a group consisting of Al and Ni, Ti, W, Co, Cr, Ge or Ca. A manufactured Si-based amorphous alloy is heat-treated in a preset condition to have a microstructure in which a crystalline Si phase which is an active metal having a size of 100 nm or less is uniformly dispersed and precipitated in a non-active metal amorphous matrix phase or a non-active crystalline matrix phase. Therefore, the lithium secondary battery of the present invention has a yield strength to withstand the expansion stress of silicon particles by intercalation of lithium ions during charging and discharging to suppress particle pulverization by volume expansion and contraction of the cathode′s active material during charging and discharging, thereby improving life characteristics.