Porous silicon-containing composite, carbon composite using the same, and electrode, lithium battery and electronic device each including the same
A porous silicon-containing composite includes: a porous core including a porous silicon composite secondary particle; and a shell on at least one surface of the porous core, the shell including a first graphene, wherein the porous silicon composite secondary particle includes an aggregate of a first primary particle including silicon, a second primary particle including a structure and second graphene on at least one surface of the first primary particle and the second primary particle, and wherein at least one of a shape and a degree of oxidation of the first primary particle and the second primary particle are different. Also an electrode including the porous silicon-containing composite, a lithium battery including the electrode, and a device including the porous silicon-containing composite or the carbon composite.
1. A porous silicon-containing composite comprising:
a porous core comprising a porous silicon composite secondary particle; and
a first shell on an outer surface of the porous core, the first shell comprising a first graphene,
wherein the porous silicon composite secondary particle comprises an aggregate of
a first primary particle comprising silicon,
a second primary particle comprising a structure, and
a second shell comprising a second graphene on at least one surface of the first primary particle and the second primary particle, and
wherein at least one of a shape and a degree of oxidation of the first primary particle and the second primary particle are different,
wherein the first primary particle has an oxygen content of about 3 atomic percent to about 15 atomic percent, based on a total content of the first primary particle, the second primary particle has an oxygen content of about 0.01 atomic percent to 3 atomic percent, based on a total content of the second primary particle.
2. The porous silicon-containing composite of claim 1 , wherein the structure comprises silicon, germanium, tin, aluminum, zinc, antimony, an alloy thereof, or a combination thereof.
3. The porous silicon-containing composite of claim 1 , wherein the first primary particle has a plate shape, a needle shape, a cube shape, a rod shape, or a combination thereof, and the second primary particle has a spherical form, a nanowire form, or a combination thereof.
4. The porous silicon-containing composite of claim 1 , wherein
an oxygen content of the porous silicon-containing composite is about 0.1 atomic percent to about 15 atomic percent, with respect to a total content of oxygen, carbon, and silicon atoms.
5. The porous silicon-containing composite of claim 1 , further comprising a silicon suboxide of the formula SiO x , wherein 0<x<2 between the primary particle and the second graphene, and the silicon suboxide has a thickness of about 30 micrometers or less.
6. The porous silicon-containing composite of claim 1 , wherein the first primary particle and the second primary particle have different shapes from each other, and
wherein the porous silicon-containing composite further comprises a third primary particle comprising silicon, the third primary particle having a nanotube shape, a nanorod shape, a nanoribbon shape, or a combination thereof.
7. The porous silicon-containing composite of claim 1 , wherein the first primary particle and the second primary particle form a network, or the second primary particle is embedded among the first primary particle.
8. The porous silicon-containing composite of claim 1 , wherein a size of the second primary particle is the same as or smaller than a size of the first primary particle.
9. The porous silicon-containing composite of claim 1 , wherein the first primary particle has a size of about 20 nanometers to about 180 nanometers, and the second primary particle has a size of about 100 nanometers or less.
10. The porous silicon-containing composite of claim 1 , wherein a mixed weight ratio of the first primary particle to the second primary particle is about 1:99 to about 99:1.
11. The porous silicon-containing composite of claim 1 , wherein the second graphene has about 1 to about 30 layers, and is disposed on the first primary particle, and
the second graphene has about 1 to about 5 layers, and is disposed on the second primary particle, and
wherein the second graphene disposed on the second primary particle is in the form of flakes and the first graphene is disposed on the second first graphene.
12. The porous silicon-containing composite of claim 1 , wherein the second graphene is directly disposed on a surface of a silicon suboxide, and the first graphene is directly disposed on a surface of the porous silicon composite secondary particle, and the porous silicon-containing composite has a double core/shell structure.
13. The porous silicon-containing composite of claim 1 , wherein an amount of silicon is about 0.1 parts to about 99 parts by weight, with respect to 100 parts by weight of a total weight of the porous silicon-containing composite, and a total amount of the first graphene and the second graphene is about 0.1 parts to about 2,000 parts by weight, with respect to 100 parts by weight of the silicon.
14. The porous silicon-containing composite of claim 13 , wherein the second graphene is disposed about 10 nanometers or less from a surface of the silicon suboxide of the formula SiO x , wherein 0<x<2, in the silicon composite primary particles, the second graphene comprises 1 to about 30 graphene layers, and has a total thickness of about 0.3 nanometers to about 1,000 nanometers, and
the second graphene is oriented at an angle of about 0° to about 90° with respect to a primary axis of the silicon-containing composite, wherein the first graphene is disposed about 1000 nanometers or less from a surface of a silicon suboxide of the formula SiO x , wherein 0<x<2, in the porous silicon composite secondary particle, the first graphene comprises 1 to about 30 graphene layers, and has a total thickness of about 0.6 nanometers to about 50 nanometers, and
the first graphene is oriented at an angle of about 0° to about 90° with respect to a primary axis of the silicon-containing composite.
15. The porous silicon-containing composite of claim 1 , wherein the porous silicon-containing composite further comprises a carbonaceous coating layer comprising amorphous carbon on at least one surface of the porous silicon-containing composite, and the carbonaceous coating layer further comprises crystalline carbon.
16. A carbon composite comprising the porous silicon-containing composite of claim 1 and a carbonaceous material.
17. An electrochemical active material composite comprising:
an electrochemical active material; and
the porous silicon-containing composite of claim 1 , a carbon composite comprising the porous silicon-containing composite and a carbonaceous material, or a combination thereof,
wherein the porous silicon-containing composite is on a surface of the electrochemical active material.
18. An electrode comprising:
the porous silicon-containing composite of claim 1 ; or
a carbon composite comprising the porous silicon-containing composite and a carbonaceous material.
19. A lithium battery comprising the electrode of claim 18 .
20. The lithium battery of claim 19 , wherein the porous silicon-containing composite comprises the first primary particle and the second primary particle after 100 or fewer charge and discharge cycles of the lithium battery, wherein graphene flakes are grown on the second primary particle.