NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY AND LITHIUM ION SECONDARY BATTERY COMPRISING THE SAME

Provided is a lithium ion secondary battery having high energy density and excellent cycle characteristics. The present invention relates to a negative electrode for a lithium ion secondary battery comprising: (i) a negative electrode mixture layer comprising a negative electrode active material and a negative electrode binder and (ii) a negative electrode current collector, wherein the negative electrode active material comprises an alloy comprising silicon (Si alloy), the Si alloy is crystalline and has a median diameter (D50 particle size) of 1.2 μm or less, and an amount of the negative electrode binder based on the weight of the negative electrode mixture layer is 12% by weight or more and 50% by weight or less.