Composite cathodes for solid-state lithium sulfur batteries and methods of manufacturing thereof
A lithium-sulfur battery includes: a substrate; a composite cathode disposed on the substrate; a solid-state electrolyte disposed on the composite cathode; and a lithium anode disposed on the solid-state electrolyte, such that the composite cathode comprises: active elemental sulfur, conductive carbon, and sulfide electrolyte, and the sulfide electrolyte is uniformly coated on at least one surface of the conductive carbon. A method of forming a composite cathode for a lithium-sulfur battery includes: synthesizing dispersed carbon fiber from cotton to form carbonized dispersed cotton fiber (CDCF) powder; in-situ coating of the CDCF with an electrolyte component to form a composite powder; and mixing active elemental sulfur powder with the composite powder to form the composite cathode.
1. A method of forming a composite cathode for a lithium-sulfur battery, comprising:
synthesizing dispersed carbon fiber from cotton to form a carbonized dispersed cotton fiber (CDCF) powder, the synthesizing comprises:
hydrolyzing the cotton in acid to forma dispersed cotton fiber (DCF); and
heating the DCF at a temperature of at least 1000° C. to form the CDCF powder; and
in-situ coating of the CDCF with an electrolyte component to form a composite powder; and
mixing active elemental sulfur powder with the composite powder to form the composite cathode.
2. A method of forming a composite cathode for a lithium-sulfur battery, comprising:
synthesizing dispersed carbon fiber from cotton to form a carbonized dispersed cotton fiber (CDCF) powder;
in-situ coating of the CDCF with an electrolyte component to form a composite powder, wherein the in-situ coating comprises:
forming a precursor powder comprising lithium sulfide (Li 2 S) and phosphorus pentasulfide (P 2 S 5 );
depositing the precursor powder on the CDCF; and
reacting Li 2 S with P 2 S 5 on the CDCF to form the composite powder; and
mixing active elemental sulfur powder with the composite powder to form the composite cathode.
3. The method of claim 2 , wherein the depositing comprises:
dissolving the precursor powder into an organic solvent containing CDCF powder; and
evaporating the organic solvent to form a precursor powder-coated CDCF,
wherein the dissolving and evaporating are conducted at a temperature below 100° C.
4. The method of claim 3 , wherein a weight ratio of organic solvent to a combined mass of Li 2 S and P 2 S 5 to a mass of CDCF during the dissolving is in a range of 40:2:1 to 80:2:1, respectively.
5. The method of claim 2 , wherein the reacting comprises:
heating the CDCF to a temperature of at least 225° C.
6. The method of claim 1 , wherein the mixing comprises:
grinding active elemental sulfur powder with the composite powder to form a sieved composite; and
heating the sieved composite to a temperature of at least 155° C.
7. A composite cathode formed by the method of claim 1 .
8. The method of claim 1 , wherein the in-situ coating comprises:
forming a precursor powder comprising lithium sulfide (Li 2 S) and phosphorus pentasulfide (P 2 S 5 );
depositing the precursor powder on the CDCF; and
reacting Li 2 S with P 2 S 5 on the CDCF to form the composite powder.
9. The method of claim 8 , wherein the depositing comprises:
dissolving the precursor powder into an organic solvent containing CDCF powder; and
evaporating the organic solvent to form a precursor powder-coated CDCF,
wherein the dissolving and evaporating are conducted at a temperature below 100° C.
10. The method of claim 9 , wherein a weight ratio of organic solvent to a combined mass of Li 2 S and P 2 S 5 to a mass of CDCF during the dissolving is in a range of 40:2:1 to 80:2:1, respectively.
11. The method of claim 8 , wherein the reacting comprises:
heating the CDCF to a temperature of at least 225° C.
12. The method of claim 1 , wherein the electrolyte component comprises at least one of: Li 10 GeP 2 S 12 , β-Li 3 PS 4 , Li 9.6 P 3 S 12 , Li 3 PS 4 , and Li 7 P 3 S 11 .
13. The method of claim 1 , wherein the CDCF comprises an average fiber length from 100 μm to 200 μm.
14. The method of claim 2 , wherein the mixing comprises:
grinding active elemental sulfur powder with the composite powder to form a sieved composite; and
heating the sieved composite to a temperature of at least 155° C.
15. The method of claim 2 , wherein the electrolyte component comprises at least one of: Li 10 GeP 2 S 12 , β-Li 3 PS 4 , Li 9.6 P 3 S 12 , Li 3 PS 4 , and Li 7 P 3 S 11 .
16. The method of claim 2 , wherein the CDCF comprises an average fiber length from 100 μm to 200 μm.
17. A composite cathode formed by the method of claim 2 .