Composite for anode active material, anode including the composite, lithium secondary battery including the anode, and method of preparing the composite
A composite anode active material, the composite including: a metal particle; a carbon-containing material, and a garnet-type lithium ion conductor, wherein an amount of the garnet-type lithium ion conductor is greater than 1 part by weight and less than 5 parts by weight, based on 100 parts by weight of a total weight of the metal particle, the carbon-containing material, and the garnet-type lithium ion conductor.
1. A composite anode active material, the composite consisting of:
a metal particle;
a carbon-containing material; and
a garnet-type lithium ion conductor,
wherein an amount of the garnet-type lithium ion conductor is greater than 1 part by weight and less than 5 parts by weight, based on 100 parts by weight of a total weight of the metal particle, the carbon-containing material, and the garnet-type lithium ion conductor.
2. The composite of claim 1 , wherein the metal particle comprises silicon, tin, germanium, aluminum, a combination thereof, or an alloy thereof.
3. The composite of claim 1 , wherein the carbon containing material comprises a carbon nanotube, a carbon nanofiber, graphene, graphite, or a combination thereof.
4. The composite of claim 1 , wherein the garnet-type lithium ion conductor comprises a garnet-type oxide represented by Formula 1A:
L 5+x E 3 Me z M 2-z X d Formula 1A
wherein, in Formula 1A,
L is a monovalent cation, a divalent cation, or a combination thereof and comprises lithium,
E is a trivalent cation,
Me and M are each independently a trivalent cation, a tetravalent cation, a pentavalent cation, or a hexavalent cation,
X comprises O, a pentavalent anion, a hexavalent anion, a heptavalent anion, or a combination thereof, and
0<x≤3, 0≤z<2, and 0<d≤12.
5. The composite of claim 4 , wherein L in Formula 1A comprises lithium, sodium, magnesium, calcium, potassium, hydrogen, or a combination thereof.
6. The composite of claim 4 , wherein Me in Formula 1A comprises a transition metal.
7. The composite of claim 4 , wherein Me in Formula 1A comprises tantalum, niobium, yttrium, scandium, tungsten, molybdenum, antimony, bismuth, hafnium, vanadium, germanium, silicon, aluminum, gallium, titanium, cobalt, indium, zinc, chromium, or a combination thereof.
8. The composite of claim 1 , wherein the garnet-type lithium ion conductor has an ionic conductivity of at least about 3.0×10 −4 siemens per centimeter at a temperature of 25° C.
9. The composite of claim 1 , wherein an amount of the metal particle is in a range of about 10 parts by weight to about 90 parts by weight, based on 100 parts by weight of the carbon-containing material.
10. The composite of claim 1 , wherein the garnet-type lithium ion conductor comprises a garnet-type oxide represented by
L 5+x E 3-a Q a Me z M 2-z X d Formula 1B
wherein, in Formula 1B,
L is a monovalent cation, a divalent cation, or a combination thereof and comprises lithium,
E is a trivalent cation,
Q is a Group 1 element having an atomic weight of at least 10,
Me and M are each independently a trivalent cation, a tetravalent cation, a pentavalent cation, or a hexavalent cation,
X comprises O, a pentavalent anion, a hexavalent anion, a heptavalent anion, or a combination thereof,
0<x≤3, 0≤z<2, 0<d≤12, and 0<a≤3.
11. The composite of claim 10 , wherein an amount of the Group 1 element having an atomic weight of at least 10 is in a range of about 0.25 part by weight to about 3.85 parts by weight, based on 100 parts of weight of a total amount of the garnet-type lithium ion conductor.
12. The composite of claim 11 , wherein the Group 1 element having an atomic weight of at least 10 is present at a grain boundary of the garnet-type oxide of Formula 1B.
13. The composite of claim 1 , wherein the garnet-type lithium ion conductor comprises a garnet-type oxide represented by Formula 2:
L 5+x+2y D y E 3-y Me z M 2-z X d Formula 2
wherein, in Formula 2,
L is a monovalent cation, a divalent cation, or a combination thereof and comprises Li,
D is a monovalent cation,
E is a trivalent cation,
Me and M are each independently a trivalent cation, a tetravalent cation, a pentavalent cation, or a hexavalent cation,
X comprises O, a pentavalent anion, a hexavalent anion, a heptavalent anion, or a combination thereof, and
0<x+2y≤3, 0<y≤0.5, 0<z<2, and 0<d≤12.
14. An anode comprising the composite of claim 1 .
15. The anode of claim 14 , further comprising an additional anode active material.
16. A lithium secondary battery comprising the anode of claim 14 .
17. A method of preparing the composite of claim 1 , the method comprising:
mixing a metal particle and a garnet-type lithium ion conductor to form a first mixture;
milling the first mixture;
mixing the milled first mixture with a carbon-containing material to form a second mixture; and
milling the second mixture to preparing the composite.
18. The composite of claim 1 , wherein the amount of the garnet-type lithium ion conductor is about 2 parts by weight to about 3 parts by weight, based on 100 parts by weight of the total amount of the metal particle, the carbon-based material, and the garnet-type lithium ion conductor.
19. The composite of claim 1 , wherein an amount of the metal particle is in a range of about 50 parts by weight to about 88 parts by weight, based on 100 parts by weight of the carbon-containing material.
20. The composite of claim 1 , wherein the metal particle comprises silicon.