Cathode active material and lithium secondary battery containing the same

  • US 9,246,162 B2
  • Filed: 08/12/2013
  • Issued: 01/26/2016
  • Est. Priority Date: 04/18/2011
  • Status: Active Grant
First Claim
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1. A cathode active material for secondary batteries, the cathode active material being a mixture comprising at least one type of lithium manganese oxide (A) having a spinel crystal structure and at least two types of lithium nickel-manganese-cobalt composite oxides (B) containing Ni, Mn, and Co as transition metals,wherein the lithium nickel-manganese-cobalt composite oxides (B) are different from each other in terms of at least one selected from the group consisting of particle diameter, and density,wherein the lithium manganese oxide has a spinel crystal structure and has an elemental composition represented by Formula (1) and the lithium nickel-manganese-cobalt composite oxides are selected from compounds having an elemental composition represented by Formula (2):


  • Li1+xMn2−

    y
    MyO4



    (1)
    Li1+zNiaMnbCo1−

    (ab)
    O2



    (2)where 0≦

    x≦

    0.2 and 0≦

    y≦

    1,where M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W and Bi, andwhere 0≦

    z≦

    0.1, 0.2≦

    a≦

    0.7, 0.2≦

    b≦

    0.7 and a+b<

    1,wherein the lithium nickel-manganese-cobalt composite oxides (B) comprise two types of oxides having the same elemental composition and different particle diameters,wherein the lithium nickel-manganese-cobalt composite oxides (B) comprising a first oxide (B1) and a second oxide (B2) have an average particle diameter in a range from 3 to 10 μ

    m and an average particle diameter of the first oxide (B1) is 10 to 70% of an average particle diameter of the second oxide (B2), andwherein the mixture ratio of the first oxide (B1) and the second oxide (B2) is 50;

    50 by weight.

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