Negative electrode and secondary battery

Abstract

Negative electrode for a secondary battery, comprising: a current collector; a first active material layer of the negative electrode provided on the current collector;and a second active material layer of the negative electrode provided on the first active material layer of the negative electrode, wherein the porosity of the second active material layer of the negative electrode is 5% to 20% higher than the porosity of the first active material layer of the negative electrode, wherein the first and second active material layers of the negative electrode each comprise an active material of the negative electrode, wherein the active material of the negative electrode comprises a silicon-based active material, synthetic graphite and natural graphite, and the silicon-based active material comprises at least one of SiOx(0≤x<2), SiMy(M is metal, 1≤y≤4) and Si / C, and wherein the silicon-based active material is contained in an amount of 1 to 40 parts by weight based on a total of 100 parts by weight of the active material contained in each of the first and second active material layers of the negative electrode.