Negative electrode for secondary battery

A negative electrode comprising:

• a current collector;
• a first active material layer comprising first active material particles and disposed on the current collector;
• and
• a second active material layer comprising second active material particles and disposed on the first active material layer,
• wherein a lithium ion diffusion rate of the second active material particles is two to three times a lithium ion diffusion rate of the first active material particles,
• the first active material particles comprise natural graphite, and the second active material particles comprise artificial graphite,
• the artificial graphite has an orientation index of 12 to 14,
• the first active material layer further comprises a first binder and a conductive material, and the second active material layer further comprises a second binder and the conductive material,
• the second binder comprises a copolymer of hexafluoropropylene (HFP) and at least one selected from the group consisting of polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR),
• a content of the second active material particles ranges from 30% to 90% with respect to a total content of the first and second active material particles, and
• the lithium ion diffusion rate of the first active material particles is in a range of 5.0×10−9 cm2/s to 7.0×10−9 cm2/s, and the lithium ion diffusion rate of the second active material particles is in a range of 1.0×10−8 cm2/s to 2.0×10−8 cm2/s,
• wherein the orientation index is an area ratio of (004)/(110) obtained by measuring planes (110) and (004) of the artificial graphite by XRD and then integrating an intensity of a peak for the (110) plane and an intensity of a peak for the (004) plane.