Positive-electrode active material for lithium secondary cell, positive electrode for lithium secondary cell, and lithium secondary cell
A positive electrode active material for a lithium secondary cell, having a layered structure and comprising at least nickel, cobalt and manganese, the positive electrode active material satisfying requirements (1), (2) and (3) below: (1) a composition represented by a composition formula: Li[Li x (Ni α Co β Mn γ M δ ) 1-x ]O 2 , wherein 0≤x≤0.10, 0.30<α≤0.34, 0.30<β≤0.34, 0.32≤γ<0.40, 0≤δ≤0.10, β<γ, δ+α+β+γ=1, M represents at least one metal selected from the group consisting of Fe, Cu, Ti, Mg, Al, W, Zn, Sn, Zr, Ga and V; (2) a secondary particle diameter of 2 μm or more and 10 μm or less; and (3) a maximum peak value in a pore diameter range of 90 nm to 150 nm in a pore diameter distribution determined by mercury porosimetry.
1. A positive electrode active material for a lithium secondary cell, having a layered structure and comprising at least nickel, cobalt and manganese, the positive electrode active material satisfying requirements (1), (2), and (3) below:
(1) a composition represented by a composition formula:
Li[Li x (Ni α Co β Mn γ M δ ) 1-x ]O 2 ,
wherein 0≤x≤0.10, 0.30<α≤0.34, 0.30<β≤0.34, 0.32≤γ<0.40, 0≤δ≤0.10, β<γ, δ+α+β+γ=1, M represents at least one metal selected from the group consisting of Fe, Cu, Ti, Mg, Al, W, Zn, Sn, Zr, Ga and V;
(2) a secondary particle diameter of 2 μm or more and 10 μm or less; and
(3) a maximum peak value in a pore diameter range of 90 nm to 150 nm in a pore diameter distribution determined by mercury porosimetry.
2. The positive electrode active material according to claim 1 , wherein the secondary particle diameter is 2.5 μm or more and 7 μm or less.
3. The positive electrode active material according to claim 1 , wherein a pore volume of pores having diameters in the range of 10 nm to 200 nm in the pore distribution determined by mercury porosimetry is 0.025 cm 3 /g or more and 0.045 cm 3 /g or less.
4. A positive electrode for a lithium secondary cell, comprising the positive electrode active material of claim 1 .
5. A positive electrode for a lithium secondary cell, comprising the positive electrode active material of claim 3 .
6. A lithium secondary cell, comprising the positive electrode of claim 4 .
7. The positive electrode active material according to claim 2 , which has a BET specific surface area of 1.5 m 2 /g or more and 2.5 m 2 /g or less.
8. The positive electrode active material according to claim 2 , wherein a pore volume of pores having diameters in the range of 10 nm to 200 nm in the pore distribution determined by mercury porosimetry is 0.025 cm 3 /g or more and 0.045 cm 3 /g or less.
9. A positive electrode for a lithium secondary cell, comprising the positive electrode active material of claim 2 .
10. A lithium secondary cell, comprising the positive electrode of claim 8 .
11. A lithium secondary cell, comprising the positive electrode of claim 9 .
12. The positive electrode active material according to claim 1 , which has a BET specific surface area of 1.5 m 2 /g or more and 2.5 m 2 /g or less.
13. The positive electrode active material according to claim 12 , wherein a pore volume of pores having diameters in the range of 10 nm to 200 nm in the pore distribution determined by mercury porosimetry is 0.025 cm 3 /g or more and 0.045 cm 3 /g or less.
14. A positive electrode for a lithium secondary cell, comprising the positive electrode active material of claim 12 .