Cathode active material and non-aqueous electrolyte secondary battery
View Patent ↗A cathode active material and non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery includes a positive electrode and a negative electrode which are electrochemically doped and dedoped with lithium; and an electrolyte disposed between the positive electrode and the negative electrode. The positive electrode contains a cathode active material including a mixture of: a first cathode active material represented by a general formula: Li t CoM s O 2 where M represents a metal, 0≦s≦0.03, and 0.05≦t≦1.15; and a second cathode active material represented by a general formula: Li x Ni (1-y-z) Co y Mn z A a O 2 where A represents a metal, 0.05≦x≦1.15, 0.15≦y+z≦0.70, 0.05≦z≦0.40, and 0≦a≦0.10.
1. A cathode active material comprising a mixture of:
a first cathode active material having a formula: Li t CoM s O 2 , where M represents a metal, 0≦s≦0.03, and 0.05≦t≦1.15; and
a second cathode active material having a formula: Li x Ni (l-y-z) Co y Mn z A a O 2 , where A represents a metal, 0.05≦x≦1.15, 0.15≦y+z≦0.70, 0.05≦z≦0.40, and 0≦a≦0.10; and where the second cathode material is composed of secondary particles formed from an aggregate of primary particles; and
wherein the content of the second cathode active material in the cathode active material ranges from about 10% to about 40% by weight.
2. The cathode active material according to 1 , wherein:
the second cathode active material has a specific surface area that ranges from about 0.2 m 2 /g to about 1.5 m 2 /g, both inclusive.
3. The cathode active material according to 1 , wherein:
the metal M and/or A contains a component selected from the group consisting of magnesium, aluminum and combinations thereof.
4. A non-aqueous electrolyte secondary battery comprising:
a positive electrode and a negative electrode which are electrochemically doped and dedoped with lithium; and
an electrolyte disposed between the positive electrode and the negative electrode;
wherein the positive electrode contains a cathode active material including a mixture of:
a first cathode active material having a formula: Li t CoM s O 2 , where M represents a metal, 0≦s≦0.03, and 0.05≦t≦1.15;
a second cathode active material having a formula: Li x Ni (l-y-z) Co y Mn z A a O 2 , where A represents a metal, 0.05≦x≦1.15, 0.15≦y+z≦0.70, 0.05≦z≦0.40, and 0≦a≦0.10, and where the second cathode material is composed of secondary particles formed from an aggregate of primary particles; and
wherein the content of the second cathode active material in the cathode active material ranges from about 10% to about 40% by weight.
5. The non-aqueous electrolyte secondary battery according to claim 4 , wherein:
the second cathode active material has a specific surface area that ranges from about 0.2 m 2 /g to about 1.5 m 2 /g, both inclusive.
6. The non-aqueous electrolyte secondary battery according to claim 4 , wherein:
the positive electrode has an electrode volume density that ranges from about 3.1 g/cm 3 to about 3.7 g/cm 3 , both inclusive.
7. The non-aqueous electrolyte secondary battery according to claim 4 , wherein:
the metal M and/or A contains at least one of magnesium and aluminum.
8. The cathode active material according to 1 , wherein:
the mixture of the first and second cathode active materials comprises particles having an average particle size ranging from 2 μm to 30 μm.
9. The non-aqueous electrolyte secondary battery according to claim 4 , wherein:
the mixture of the first and second cathode active materials comprises particles having an average particle size ranging from 2 μm to 30 μm.
10. The cathode active material according to 1 , wherein:
the first cathode active material includes Li t CoO 2 , Li t CoAl s O 2 and LiCoMg s O 2 .
11. The cathode active material according to 1 , wherein:
the second cathode active material includes Li x Ni (l-y-z) CO yMn z O 2 and Li x Ni (l-y-z) CO y Mn z Al a O 2 .
12. The cathode active material according to 1 , wherein:
the first cathode active material includes Li t CoO 2 , Li t CoAl s O 2 and LiCoMg s O 2 .
the second cathode active material includes Li x Ni (l-y-z) CO yMn z O 2 and Li x Ni (l-y-z) CO y Mn z Al a O 2 .
13. The non-aqueous electrolyte secondary battery according to claim 4 , wherein:
the first cathode active material includes Li t CoO 2 , Li t CoAl s O 2 and LiCoMg s O 2 .
14. The non-aqueous electrolyte secondary battery according to claim 4 , wherein:
the second cathode active material includes Li x Ni (l-y-z) CO yMn z O 2 and Li x Ni (l-y-z) CO y Mn z Al a O 2 .
15. The non-aqueous electrolyte secondary battery according to claim 4 , wherein:
the first cathode active material includes Li t CoO 2 , Li t CoAl s O 2 and LiCoMg s O 2 .
the second cathode active material includes Li x Ni (l-y-z) CO yMn z O 2 and Li x Ni (l-y-z) CO y Mn z Al a O 2 .