Lithium-sulfur battery and methods of preventing insoluble solid lithium-polysulfide deposition
An improved lithium-sulfur battery containing a surface-functionalized carbonaceous material. The presence of the surface-functionalized carbonaceous material generates weak chemical bonds between the functional groups of the surface-functionalized carbonaceous material and the functional groups of the polysulfides, which prevents the polysulfide migration to the battery anode, thereby providing a battery with relatively high energy density and good partial discharge efficiency.
1. A non-aqueous lithium-sulfur electrochemical cell, comprising:
an anode including an anode material comprising lithium;
a cathode including a cathode material comprising sulfur;
a separator disposed between the anode and the cathode;
a non-aqueous electrolyte which is in fluid communication with the anode, the cathode, and the separator; and
a layer containing a surface-functionalized carbonaceous material disposed between the anode and the cathode.
2. The lithium-sulfur electrochemical cell of claim 1 , wherein the layer has a porosity that allows the electrolyte to flow through the layer.
3. The lithium-sulfur electrochemical cell of claim 1 , comprising two or more layers containing the surface-functionalized carbonaceous material, the two or more layers being disposed between the anode and the cathode.
4. The lithium-sulfur electrochemical cell of claim 1 , wherein the layer contains the surface-functionalized carbonaceous material in an amount of from 0.001% to 90% by weight based on a total weight of the layer.
5. The lithium-sulfur electrochemical cell of claim 4 , wherein the layer contains the surface-functionalized carbonaceous material in an amount of from about 1% to about 70% by weight based on a total weight of the layer.
6. The lithium-sulfur electrochemical cell of claim 1 , wherein the layer containing the surface-functionalized carbonaceous material has a thickness of from 5 μm to 200 μm.
7. The lithium-sulfur electrochemical cell of claim 1 , wherein the layer containing the surface-functionalized carbonaceous material is disposed between the separator and the cathode.
8. The lithium-sulfur electrochemical cell of claim 7 , wherein the layer containing the surface-functionalized carbonaceous material is disposed at a distance from the cathode that is less than a distance between the layer and the separator.
9. The lithium-sulfur electrochemical cell of claim 1 , wherein the layer containing the surface-functionalized carbonaceous material is a free-standing sheet.
10. The lithium-sulfur electrochemical cell of claim 9 , wherein the free-standing sheet is located between the separator and the cathode.
11. The lithium-sulfur electrochemical cell of claim 1 , wherein the surface-functionalized carbonaceous material is located on a surface of the cathode and/or the separator.
12. The lithium-sulfur electrochemical cell of claim 11 , wherein the layer containing the surface-functionalized carbonaceous material is located on a surface of the cathode.
13. The lithium-sulfur electrochemical cell of claim 11 , wherein the layer containing the surface-functionalized carbonaceous material is located on a surface of the separator interposed between the anode and the cathode.
14. The lithium-sulfur electrochemical cell of claim 1 , wherein the surface-functionalized carbonaceous material is a carbonaceous material functionalized with chemical moieties that interact with polysulfide functional groups.
15. The lithium-sulfur electrochemical cell of claim 14 , wherein the surface-functionalized carbonaceous material is functionalized in an amount such that the chemical moieties make up 1% to 30% by weight of the surface-functionalized carbonaceous material.
16. The lithium-sulfur electrochemical cell of claim 1 , wherein the surface-functionalized carbonaceous material is a carbonaceous material functionalized with amine and/or amide groups.
17. The lithium-sulfur electrochemical cell of claim 1 , wherein the cell is a battery.
18. The lithium-sulfur electrochemical cell of claim 1 , wherein the cathode material comprises from about 20% to about 95% sulfur by weight based on a total weight of the cathode.
19. The lithium-sulfur electrochemical cell of claim 1 , wherein the cathode material is loaded onto a surface of a substrate in an average loading amount in a range of from about 1 to about 40 mg/cm 2 , the cathode material comprising from 0.001% to 70% by weight, based on a total weight of the cathode, of a surface-functionalized carbon material as a conductive additive.
20. The lithium-sulfur electrochemical cell of claim 1 , wherein the anode further comprises a metal selected from the group consisting of magnesium, sodium, and potassium.
21. The lithium-sulfur electrochemical cell of claim 1 , wherein the anode further comprises one or more members selected from the group consisting of LiMg, LiAl, LiAlMg, LiS, LiB, and LiSB.
22. The lithium-sulfur electrochemical cell of claim 1 , wherein the non-aqueous electrolyte comprises one or more organic solvents selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate, dioxolane (DOL), 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), methyl acetate (MA), diglyme, triglyme, tetraglyme, propylene carbonate (PC), ethylene carbonate (EC), acetonitrile, dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, gamma-butyrolactone (GBL), and N-methyl-pyrrolidinone (NMP).
23. The non-aqueous lithium-sulfur electrochemical cell of claim 1 , wherein the non-aqueous electrolyte comprises two or more organic solvents selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate, dioxolane (DOL), 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), methyl acetate (MA), diglyme, triglyme, tetraglyme, propylene carbonate (PC), ethylene carbonate (EC), acetonitrile, dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, gamma-butyrolactone (GBL), and N-methyl-pyrrolidinone (NMP).
24. The non-aqueous lithium-sulfur electrochemical cell of claim 1 , wherein the non-aqueous electrolyte comprises a salt having a formula LiMF 6 or LiMF 4 , wherein M is an element selected from the group consisting of phosphorous, arsenic, antimony and boron.
25. The non-aqueous electrochemical cell of claim 24 , wherein the salt is one or more member selected from the group consisting of LiPF 6 , LiAsF 6 , LiTFSI, LiFSI, LiSbF 6 , LiBF 4 , LiClO 4 , LiAlCl 4 , LiGaCl 4 , LiC(SO 2 CF 3 ) 3 , LiB(C 6 H 4 O 2 ) 2 , LiN(CF 3 SO 2 ) 2 and Li(CF 3 SO 3 ).
26. The lithium-sulfur electrochemical cell of claim 19 , wherein the cathode material further comprises one or more conductive additive selected from the group consisting of carbon black and graphite.
27. The lithium-sulfur electrochemical cell of claim 1 , wherein the non-aqueous electrolyte comprises an ionic liquid of 1-n-butyl-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYR14TFSI).
28. The lithium-sulfur electrochemical cell of claim 27 , wherein the non-aqueous electrolyte further comprises one or more organic solvents selected from the group consisting of hexamethylphosphoramide (HMPA) and dimethyl sulfoxide (DMSO).
29. A method of charging a lithium-sulfur electrochemical cell, comprising:
supplying electrical energy to the lithium-sulfur electrochemical cell at a constant current;
monitoring the voltage during charging; and
terminating the charge when the monitored voltage is in a range of about 2.4 volts to about 3.0 volts,
the lithium-sulfur electrochemical cell comprising:
an anode including an anode material comprising lithium;
a cathode including a cathode material comprising sulfur;
a separator disposed between the anode and the cathode;
a non-aqueous electrolyte which is in fluid communication with the anode, the cathode, and the separator; and
a layer containing a surface-functionalized carbonaceous material disposed between the anode and the cathode, wherein functional groups of the surface-functionalized carbonaceous material interact with functional groups of polysulfides and slow the rate of migration of the polysulfides.
30. The method of claim 29 , wherein the surface-functionalized carbonaceous material is a carbonaceous material functionalized with amine and/or amide groups.
31. The method of claim 29 , wherein the layer contains the surface-functionalized carbonaceous material in an amount of from about 0.001% to about 90% by weight of the layer.
32. A method for manufacturing a non-aqueous lithium-sulfur electrochemical cell, comprising:
introducing a surface-functionalized carbonaceous material into the non-aqueous lithium-sulfur electrochemical cell, wherein the surface-functionalized carbonaceous material is a carbonaceous material functionalized with chemical moieties that are capable of interacting with and non-covalently bonding polysulfides to the carbonaceous material.
33. The method of claim 32 , wherein the surface-functionalized carbonaceous material is introduced as a free-standing sheet between an anode and a cathode of the non-aqueous lithium-sulfur electrochemical cell.
34. The method of claim 32 , wherein the surface-functionalized carbonaceous material is introduced as a free-standing sheet between a separator and a cathode of the non-aqueous lithium-sulfur electrochemical cell.
35. The method of claim 33 , wherein introducing the surface-functionalized carbonaceous material comprises laminating the surface-functionalized carbonaceous material to a surface of the cathode.
36. The method of claim 32 , wherein the non-aqueous lithium-sulfur electrochemical cell is a battery.