Sulfur-carbon composite material, its application in lithium-sulfur battery and method for preparing said composite material
The present invention provides a sulfur-carbon composite material, said composite material comprising a porous carbon substrate containing both micropores and mesopores and sulfur, wherein the sulfur is only contained in the micropores of the carbon substrate. Moreover, a lithium-sulfur battery with its cathode comprising said sulfur-carbon composite material and the method for preparing such material is also provided.
1. A sulfur-carbon composite material, comprising:
a porous carbon substrate containing both micropores and mesopores; and
sulfur, wherein:
the sulfur is only contained in the micropores of the carbon substrate,
the micropores have an average diameter of 0.4-2 nm,
the mesopores have an average diameter of 3-8 nm, and
said porous carbon substrate is made from pyrolysis microporous carbon spheres with a diameter of greater than 600 nm.
2. The composite material according to claim 1 , wherein the porous carbon substrate has a specific area of 200-1800 m 2 /g and a total pore volume of 0.15-3.0 cm 3 /g.
3. The composite material according to claim 2 , wherein the porous carbon substrate has a specific area of 500-1500 m 2 /g.
4. The composite material according to claim 1 , wherein the micropores contribute to a larger percent of the total pore volume of the porous carbon substrate than the mesopores.
5. The composite material according to claim 1 , wherein said porous carbon substrate is made from pyrolysis microporous carbon spheres with a diameter of 20 μm.
6. The composite material according to claim 1 , wherein said composite material has a sulfur load amount of 20-90 wt %.
7. The composite material according to claim 1 , wherein the sulfur is with chain structure.
8. The composite material according to claim 7 , wherein the diameter of said sulfur with chain structure is less than the diameter of the micropores.
9. The composite material according to claim 5 , wherein said porous carbon substrate is made from pyrolysis microporous carbon spheres with a diameter of 2 μm.