Negative electrode active material and Secondary battery including the same

摘要

Provided are a negative electrode active material and a secondary battery including the same, more particularly relates to a negative electrode active material including a Si-metal alloy, which can provide a high-capacity battery, and a secondary battery which can retain a high capacity due to little volumetric expansion during charging and discharging, thereby demonstrating an excellent life characteristic of the secondary battery. The negative electrode active material includes a Si-metal alloy comprising a crystalline Si having a crystal grain size of 35 nm or less.