Positive electrode active material for lithium secondary battery
Provided is a lithium secondary battery using a positive electrode active material which operates at a charging voltage in a region exceeding 4.3 V, and a novel positive electrode active material for a lithium secondary battery which can further enhance the output characteristics. Proposed is a positive electrode active material for a lithium secondary battery including positive electrode active material particles obtained by equipping the entire surface or a part of the surface of lithium manganese-containing composite oxide particles (also referred to as the “core particles”) operating at a charging voltage in a region exceeding 4.3 V in a metal Li reference potential with a layer A containing at least Ti, Al, Zr, or two or more kinds of these, and C.
1. A positive electrode active material for a lithium secondary battery comprising positive electrode active material particles, wherein the positive electrode active material particles have a layer (referred to as the “layer A”) on a part of a surface of lithium manganese-containing composite oxide particles (also referred to as the “core particles”) operating at a charging voltage in a region exceeding 4.3 V in a metal Li reference potential,
wherein the layer A comprises at least:
a) titanium (Ti), aluminum (Al), zirconium (Zr), titanium (Ti) and aluminum (Al), or aluminum (Al) and zirconium (Zr),
b) an organic functional group, and
c) phosphorus, and
wherein the layer A does not comprise fluorine (F).
2. A positive electrode active material for a lithium secondary battery comprising positive electrode active material particles, wherein the positive electrode active material particles have a layer (referred to as the “layer A”) on a part of a surface of lithium manganese-containing composite oxide particles (also referred to as the “core particles”) operating at a charging voltage in a region exceeding 4.3 V in a metal Li reference potential,
wherein the layer A is a layer formed by using a coupling agent containing no fluorine (F) but containing at least: carbon (C), and titanium (Ti), aluminum (Al), zirconium (Zr), titanium (Ti) and aluminum (Al), or aluminum (Al) and zirconium (Zr), and wherein the layer A comprises phosphorus.
3. The positive electrode active material for a lithium secondary battery according to claim 1 , wherein a content of carbon is from 0.1 to 0.5% by mass.
4. The positive electrode active material for a lithium secondary battery according to claim 1 , wherein a thickness of the layer A is from 0.1 to 200 nm.
5. The positive electrode active material for a lithium secondary battery according to claim 1 , wherein the positive electrode active material has a specific surface area of from 0.01 to 3.00 m 2 /g.
6. The positive electrode active material for a lithium secondary battery according to claim 1 , wherein D50 according to a volume-based particle size distribution obtained by measuring by a laser diffraction and scattering particle size distribution measuring method is from 5 to 40 μm.
7. The positive electrode active material for a lithium secondary battery according to claim 1 , wherein D10 according to a volume-based particle size distribution obtained by measuring by a laser diffraction and scattering particle size distribution measuring method is from 2 to 20 μm.
8. The positive electrode active material for a lithium secondary battery according to claim 1 , wherein Dmin according to a volume-based particle size distribution obtained by measuring by a laser diffraction and scattering particle size distribution measuring method is 10 μm or less.
9. The positive electrode active material for a lithium secondary battery according to claim 1 , wherein the lithium manganese-containing composite oxide particles are spinel-type lithium manganese-containing composite oxide particles having an operating potential of 4.5 V or more at a metal Li reference potential.
10. The positive electrode active material for a lithium secondary battery according to claim 1 , wherein the lithium manganese-containing composite oxide particles are spinel-type lithium manganese-containing composite oxide particles including a crystal phase obtained by substituting a part of Mn sites in LiMn 2 O 4-δ with Li, a metal element M1, and another metal element M2.
11. A lithium secondary battery comprising the positive electrode active material for a lithium secondary battery according to claim 1 .
12. The lithium secondary battery comprising the positive electrode active material for a lithium secondary battery according to claim 2 .
13. The positive electrode active material for a lithium secondary battery according to claim 2 , wherein a content of carbon is from 0.1 to 0.5% by mass.
14. The positive electrode active material for a lithium secondary battery according to claim 2 , wherein the lithium manganese-containing composite oxide particles are spinel-type lithium manganese-containing composite oxide particles having an operating potential of 4.5 V or more at a metal Li reference potential.
15. The positive electrode active material for a lithium secondary battery according to claim 3 , wherein the lithium manganese-containing composite oxide particles are spinel-type lithium manganese-containing composite oxide particles having an operating potential of 4.5 V or more at a metal Li reference potential.
16. The positive electrode active material for a lithium secondary battery according to claim 2 , wherein the lithium manganese-containing composite oxide particles are spinel-type lithium manganese-containing composite oxide particles including a crystal phase obtained by substituting a part of Mn sites in LiMn 2 O 4-δ with Li, a metal element M1, and another metal element M2.