NEGATIVE ELECTRODE INCLUDING SILICON-BASED NEGATIVE ELECTRODE ACTIVE MATERIAL AND SECONDARY BATTERY INCLUDING THE SAME
Provided are a negative electrode including a silicon-based negative electrode active material and a secondary battery including the same. The negative electrode for a secondary battery including: a current collector and a negative electrode active material layer including a plurality of silicon-based active material particles, which is positioned on the current collector may be provided, wherein the following Relation is satisfied: [Relation 1] 0.01≤A−B≤0.81, wherein A is an average value of Raman spectrum peak intensity ratios Ia/Ib for 50 silicon-based active material particles randomly selected in the negative electrode active material layer, B is an average value or values excluding top 10 values and bottom 10 values, for each Raman spectrum peak intensity ratio Ia/Ib value for the 50 silicon-based active material particles, Ia is a peak intensity at 515±15 cm −1 , and Ib is a peak intensity at 470±30 cm −1 .
1 . A negative electrode for a secondary battery comprising:
a current collector; and a negative electrode active material layer including a plurality of silicon-based active material particles, which is positioned on the current collector,
wherein the following Relation 1 is satisfied:
0.01 ≤A−B≤ 0.81 [Relation 1]
wherein A is an average value of Raman spectrum peak intensity ratios Ia/Ib for 50 silicon-based active material particles randomly selected in the negative electrode active material layer, B is an average value of values excluding top 10 values and bottom 10 values, for each Raman spectrum peak intensity ratio Ia/Ib value for the 50 silicon-based active material particles, Ia is a peak intensity at 515±15 cm −1 , and Ib is a peak intensity at 470±30 cm −1 .
2 . The negative electrode for a secondary battery of claim 1 , wherein the silicon-based active material is at least one selected from the group consisting of silicon, a silicon oxide (SiO x , 0<x≤2), a silicon alloy, and a silicon/carbon composite.
3 . The negative electrode for a secondary battery of claim 1 , wherein the silicon-based active material includes a silicon oxide pretreated with a metal.
4 . The negative electrode for a secondary battery of claim 3 , wherein the silicon oxide pretreated with a metal includes a silicon oxide (SiO x , 0<x≤2); and a metal silicate positioned on at least a part of the silicon oxide (M a Si b O c , M is Li or Mg, 1≤a≤6, 1≤b<3, and 0<c≤7).
5 . The negative electrode for a secondary battery of claim 3 , wherein the silicon oxide pretreated with a metal includes 40 to 95 wt % of a metal silicate with respect to a total weight.
6 . The negative electrode for a secondary battery of claim 1 , wherein the following Relation 2 is further satisfied:
0.01 ≤A−C≤ 0.65 [Relation 2]
wherein A is an average value of Raman spectrum peak intensity ratios Ia/Ib for 50 silicon-based active material particles randomly selected in the negative electrode active material layer, C is an average value of values excluding top 5 values and bottom 5 values, for each Raman spectrum peak intensity ratio Ia/Ib value for the 50 silicon-based active material particles, Ia is a peak intensity at 515±15 cm −1 , and Ib is a peak intensity at 470±30 cm −1 .
7 . The negative electrode for a secondary battery of claim 6 , wherein at least one selected from the following Relation 3a, Relation 3b, and Relation 3c is satisfied:
0.3≤A≤8.50 [Relation 3a]
0.3≤B≤7.71 [Relation 3b]
0.3≤C≤7.91 [Relation 3c]
wherein A is an average value of Raman spectrum peak intensity ratios Ia/Ib for 50 silicon-based active material particles randomly selected in the negative electrode active material layer, B is an average value of values excluding top 10 values and bottom 10 values, for each Raman spectrum peak intensity ratio Ia/Ib value for the 50 silicon-based active material particles, C is an average value of values excluding top 5 values and bottom 5 values, for each Raman spectrum peak intensity ratio Ia/Ib value for the 50 silicon-based active material particles.
8 . The negative electrode for a secondary battery of claim 1 , wherein the negative electrode active material layer includes 10 wt % or more of the silicon-based active material particles with respect to a total weight of the negative electrode active material.
9 . A method for producing a negative electrode for a secondary battery, the method comprising:
a) mixing silicon compound particles and a metal precursor at 200 to 800 rpm;
b) preliminarily heat treating a product from a) at 100° C. or higher and lower than 500° C.; and
c) heat treating a product from b) at 500 to 800° C., thereby preparing a negative electrode active material.
10 . The method for producing a negative electrode for a secondary battery of claim 9 , further comprising:
before a), p1) mixing Si powder and SiO 2 powder and heat treating the mixture at lower than 900° C., thereby preparing the silicon compound particles.
11 . The method for producing a negative electrode for a secondary battery of claim 9 , further comprising:
before a), p1) mixing Si powder and SiO 2 powder and heat treating the mixture at lower than 900° C.; and
p2) heat treating a product from p1) at lower than 800° C. in the presence of a hydrocarbon gas, thereby preparing the silicon compound particles.
12 . A secondary battery comprising the negative electrode of claim 1 .