NEGATIVE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY COMPRISING SAME

摘要

The present invention relates to a negative active material for a lithium secondary battery and the lithium secondary battery comprising the same. The negative active material for the lithium secondary battery of the present invention comprises: silicon; and a silicon alloy which includes at least one kind of metal except the silicon, and is capable of being alloyed with lithium, wherein the volume of an inactive region that does not react to lithium contained within the silicon alloy is 50% to 75% relative to the entire volume of the active material. The negative active material of the present invention has a higher capacity than a carbon-based negative active material, embodies a small volume expansion after being charged and discharged, and shows a high capacity maintenance rate, thereby expressing an excellent cycle property.