Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries
The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.
1. A sulfur-carbon composite material useful as a cathodic material in a lithium ion battery, the sulfur-carbon composite material comprising:
(i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and
(ii) elemental sulfur contained in at least 60 vol % of said micropores while no more than 5 vol % of the mesopores is occupied by elemental sulfur.
2. The sulfur-carbon composite material of claim 1 , wherein at least 10% and no more than 90% of the pore volume of the bimodal porous carbon component is attributable to micropores.
3. The sulfur-carbon composite material of claim 1 , wherein at least 20% and no more than 90% of the pore volume of the bimodal porous carbon component is attributable to micropores.
4. The sulfur-carbon composite material of claim 1 , wherein at least 80 vol % of the micropores is occupied by elemental sulfur.
5. The sulfur-carbon composite material of claim 1 , wherein the micropores are completely occupied by elemental sulfur.
6. A layered material useful as a cathodic material in a lithium ion battery, the layered material comprising a current collector material having coated thereon a layer of a sulfur-carbon composite material comprising:
(i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and
(ii) elemental sulfur contained in at least 60 vol % of said micropores while no more than 5 vol % of the mesopores is occupied by elemental sulfur.
7. A lithium ion battery comprising:
(a) a lithium anode
(b) a cathode comprising a sulfur-carbon composite material comprising:
(i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and
(ii) elemental sulfur contained in at least 60 vol % of said micropores while no more than 5 vol % of the mesopores is occupied by elemental sulfur; and
(c) a lithium-containing electrolyte medium in contact with said anode and cathode.
8. The lithium ion battery of claim 7 , wherein the electrolyte medium is a liquid.
9. The lithium ion battery of claim 7 , wherein the electrolyte medium is a solid or gel.
10. The lithium ion battery of claim 7 , wherein the electrolyte medium comprises a matrix material and a lithium ion electrolyte component.
11. The lithium ion battery of claim 10 , wherein the electrolyte medium further comprises a halide-containing additive.
12. The lithium ion battery of claim 11 , wherein the halide-containing additive is an inorganic halide salt.
13. The lithium ion battery of claim 12 , wherein the inorganic halide salt is an alkali halide metal salt.
14. The lithium ion battery of claim 11 , wherein the halide-containing additive is present in the electrolyte medium in an amount of at least 0.1 m concentration.
15. The lithium ion battery of claim 11 , wherein the halide-containing additive is present in the electrolyte medium in an amount of at least 0.5 m concentration.
16. The lithium ion battery of claim 10 , wherein the matrix material is comprised of one or more solvents.
17. The lithium ion battery of claim 16 , wherein the one or more solvents are polar aprotic solvents.
18. The lithium ion battery of claim 16 , wherein the one or more solvents include one or more oxyether groups.
19. The lithium ion battery of claim 7 , wherein the electrolyte medium comprises one or more solvents, a lithium ion electrolyte component, and one or more halide-containing additives.
20. The lithium ion battery of claim 19 , wherein the one or more solvents include one or more oxyether groups.