Alkali metal-sulfur secondary battery containing a nano sulfur-loaded cathode and manufacturing method

1. A rechargeable alkali metal-sulfur cell selected from lithium-sulfur cell, sodium-sulfur cell, or potassium-sulfur cell, said alkali metal-sulfur cell comprising an anode active material layer, an optional anode current collector supporting said anode active material layer, a cathode active material layer, an electrolyte with an optional porous separator layer in ionic contact with said anode active material layer and said cathode active material layer, and an optional cathode current collector supporting said cathode active material layer, wherein said cathode active material layer contains a graphite or carbon material having expanded inter-graphene planar spaces with an inter-planar spacing d 002 from 0.43 nm to 2.0 nm, as measured by X-ray diffraction, and 1%-95% by weight of sulfur or a metal polysulfide residing in said expanded inter-graphene planar spaces.

2. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said metal polysulfide contains M x S y , wherein x is an integer from 1 to 3 and y is an integer from 1 to 10, and M is a metal element selected from an alkali metal, an alkaline metal selected from Mg or Ca, a transition metal, a metal from groups 13 to 17 of the periodic table, or a combination thereof.

3. The rechargeable alkali metal-sulfur cell of claim 2 , wherein said metal element M is selected from Li, Na, K, Mg, Zn, Cu, Ti, Ni, Co, Fe, or Al.

4. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said metal polysulfide contains Li 2 S 6 , Li 2 S 7 , Li 2 S 8 , Li 2 S 9 , Li 2 S 10 , Na 2 S 6 , Na 2 S 7 , Na 2 S 8 , Na 2 S 9 , Na 2 S 10 , K 2 S 6 , K 2 S 7 , K 2 S 8 , K 2 S 9 , or K 2 S 10 .

5. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said carbon or graphite material in said cathode active material layer is selected from meso-phase pitch, meso-phase carbon, meso carbon micro-beads (MCMB), coke particles, expanded graphite flakes, artificial graphite particles, natural graphite particles, highly oriented pyrolytic graphite, soft carbon particles, hard carbon particles, multi-walled carbon nanotubes, carbon nano-fibers, carbon fibers, graphite nano-fibers, graphite fibers, carbonized polymer fibers, carbon arogel, carbon xerogel, or a combination thereof, wherein said carbon or graphite material has an inter-planar spacing d 002 from 0.27 nm to 0.42 nm prior to a chemical or physical expansion treatment and the inter-planar spacing d 002 is increased to from 0.43 nm to 2.0 nm after said expansion treatment.

6. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said carbon or graphite material is selected from graphite foam or graphene foam having pores and pore walls, wherein said pore walls contain a stack of bonded graphene planes having an expanded inter-planar spacing d 002 from 0.45 nm to 1.5 nm.

7. The rechargeable alkali metal-sulfur cell of claim 6 , wherein said stack contains from 2 to 100 graphene planes.

8. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said inter-planar spacing d 002 is from 0.5 nm to 1.2 nm.

9. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said inter-planar spacing d 002 is from 1.2 nm to 2.0 nm.

10. The rechargeable alkali metal-sulfur cell of claim 5 , wherein said expansion treatment includes an oxidation, fluorination, bromination, chlorination, nitrogenation, intercalation, combined oxidation-intercalation, combined fluorination-intercalation, combined bromination-intercalation, combined chlorination-intercalation, or combined nitrogenation-intercalation of said graphite or carbon material.

11. The rechargeable alkali metal-sulfur cell of claim 10 , further comprising a constrained thermal expansion treatment.

12. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said carbon or graphite material contains a non-carbon element selected from oxygen, fluorine, chlorine, bromine, iodine, nitrogen, hydrogen, or boron.

13. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said cell has a sulfur utilization efficiency greater than 85%.

14. A cathode active material layer for a rechargeable alkali metal-sulfur cell, wherein said cathode active material layer contains a graphite or carbon material having expanded inter-graphene planar spaces with an inter-planar spacing d 002 from 0.43 nm to 2.0 nm, as measured by X-ray diffraction, and 1%-95% by weight of sulfur or a metal polysulfide residing in said expanded inter-graphene planar spaces.

15. The cathode active material layer of claim 14 , wherein said metal polysulfide contains M x S y , wherein x is an integer from 1 to 3 and y is an integer from 1 to 10, and M is a metal element selected from an alkali metal, an alkaline metal selected from Mg or Ca, a transition metal, a metal from groups 13 to 17 of the periodic table, and combinations thereof.

16. The cathode active material layer of claim 15 , wherein said metal element M is selected from Li, Na, K, Mg, Zn, Cu, Ti, Ni, Co, Fe, or Al.

17. The cathode active material layer of claim 14 , wherein said metal polysulfide contains Li 2 S 6 , Li 2 S 7 , Li 2 S 8 , Li 2 S 9 , Li 2 S 10 , Na 2 S 6 , Na 2 S 7 , Na 2 S 8 , Na 2 S 9 , Na 2 S 10 , K 2 S 6 , K 2 S 7 , K 2 S 8 , K 2 S 9 , or K 2 S 10 .

18. The cathode active material layer of claim 14 , wherein said carbon or graphite material in said cathode active material layer is selected from meso-phase pitch, meso-phase carbon, meso carbon micro-beads (MCMB), coke particles, expanded graphite flakes, artificial graphite particles, natural graphite particles, highly oriented pyrolytic graphite, soft carbon particles, hard carbon particles, multi-walled carbon nanotubes, carbon nano-fibers, carbon fibers, graphite nano-fibers, graphite fibers, carbonized polymer fibers, carbon aerogel, carbon xerogel, or a combination thereof, wherein said carbon or graphite material has an inter-planar spacing d 002 from 0.27 nm to 0.42 nm prior to a chemical or physical expansion treatment and the inter-planar spacing d 002 is increased to from 0.43 nm to 2.0 nm after said expansion treatment.

19. The cathode active material layer of claim 14 , wherein said carbon or graphite material is selected from graphite foam or graphene foam having pores and pore walls, wherein said pore walls contain a stack of bonded graphene planes having an expanded inter-planar spacing d 002 from 0.45 nm to 1.5 nm.

20. The cathode active material layer of claim 19 , wherein said stack contains from 2 to 100 graphene planes.

21. The cathode active material layer of claim 14 , wherein said inter-planar spacing d 002 is from 0.5 nm to 1.2 nm.

22. The cathode active material layer of claim 14 , wherein said inter-planar spacing d 002 is from 1.2 nm to 2.0 nm.

23. The cathode active material layer of claim 18 , wherein said expansion treatment includes an oxidation, fluorination, bromination, chlorination, nitrogenation, intercalation, combined oxidation-intercalation, combined fluorination-intercalation, combined bromination-intercalation, combined chlorination-intercalation, or combined nitrogenation-intercalation of said graphite or carbon material.

24. The cathode active material layer of claim 23 , further comprising a constrained thermal expansion treatment.

25. The cathode active material layer of claim 14 , wherein said carbon or graphite material contains a non-carbon element selected from oxygen, fluorine, chlorine, bromine, iodine, nitrogen, hydrogen, or boron.

26. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said electrolyte is selected from polymer electrolyte, polymer gel electrolyte, composite electrolyte, ionic liquid electrolyte, non-aqueous liquid electrolyte, soft matter phase electrolyte, solid-state electrolyte, or a combination thereof.

27. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said electrolyte contains a salt selected from lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium borofluoride (LiBF 4 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium trifluoro-methanesulfonate (LiCF 3 SO 3 ), bis-trifluoromethyl sulfonylimide lithium (LiN(CF 3 SO 2 ) 2 , lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF 2 C 2 O 4 ), lithium nitrate (LiNO 3 ), Li-fluoroalkyl-phosphates (LiPF3(CF 2 CF 3 ) 3 ), lithium bisperfluoroethysulfonylimide (LiBETI), an ionic liquid salt, sodium perchlorate (NaClO 4 ), potassium perchlorate (KClO 4 ), sodium hexafluorophosphate (NaPF 6 ), potassium hexafluorophosphate (KPF 6 ), sodium borofluoride (NaBF 4 ), potassium borofluoride (KBF 4 ), sodium hexafluoroarsenide, potassium hexafluoroarsenide, sodium trifluoro-methanesulfonate (NaCF 3 SO 3 ), potassium trifluoro-methanesulfonate (KCF 3 SO 3 ), bis-trifluoromethyl sulfonylimide sodium (NaN(CF 3 SO 2 ) 2 ), sodium trifluoromethanesulfonimide (NaTFSI), bis-trifluoromethyl sulfonylimide potassium (KN(CF 3 SO 2 ) 2 ), or a combination thereof.

28. The rechargeable alkali metal-sulfur cell of claim 27 , wherein said solvent is selected from ethylene carbonate (EC), dimethyl carbonate (DMC), methylethyl carbonate (MEC), diethyl carbonate (DEC), ethyl propionate, methyl propionate, propylene carbonate (PC), gamma-butyrolactone (γ-BL), acetonitrile (AN), ethyl acetate (EA), propyl formate (PF), methyl formate (MF), toluene, xylene or methyl acetate (MA), fluoroethylene carbonate (FEC), vinylene carbonate (VC), allyl ethyl carbonate (AEC), 1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME), tetraethylene glycol dimethylether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), diethylene glycol dibutyl ether (DEGDBE), 2-ethoxyethyl ether (EEE), sulfone, sulfolane, room temperature ionic liquid, or a combination thereof.

29. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said anode active material layer contains an anode active material selected from lithium metal, sodium metal, potassium metal, a lithium metal alloy, sodium metal alloy, potassium metal alloy, a lithium intercalation compound, a sodium intercalation compound, a potassium intercalation compound, a lithiated compound, a sodiated compound, a potassium-doped compound, lithiated titanium dioxide, lithium titanate, lithium manganate, a lithium transition metal oxide, Li 4 Ti 5 O 12 , or a combination thereof.

30. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said cell is a lithium ion-sulfur cell and said anode active material layer contains an anode active material selected from the group consisting of:

(a) silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), nickel (Ni), cobalt (Co), manganese (Mn), titanium (Ti), iron (Fe), and cadmium (Cd), and lithiated versions thereof;

(b) alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, or Cd with other elements, and lithiated versions thereof, wherein said alloys or compounds are stoichiometric or non-stoichiometric;

(c) oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Fe, Ni, Co, Ti, Mn, or Cd, and their mixtures or composites, and lithiated versions thereof;

(d) salts and hydroxides of Sn and lithiated versions thereof;

(e) carbon or graphite materials and prelithiated versions thereof; and

combinations thereof.

31. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said cell is a sodium ion-sulfur cell or potassium ion-sulfur cell and said anode active material layer contains an anode active material selected from the group consisting of:

(a) sodium- or potassium-doped silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), cobalt (Co), nickel (Ni), manganese (Mn), cadmium (Cd), and mixtures thereof;

(b) sodium- or potassium-containing alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Co, Ni, Mn, Cd, and their mixtures;

(c) sodium- or potassium-containing oxides, carbides, nitrides, sulfides, phosphides, selenides, tellurides, or antimonides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Fe, Ti, Co, Ni, Mn, sd, and mixtures or composites thereof,

(d) sodium or potassium salts;

(e) particles of graphite, hard carbon, soft carbon or carbon particles and pre-sodiated versions thereof; and

combinations thereof.

32. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said cathode active material layer has an active material utilization efficiency no less than 80%.

33. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said cathode active material layer has an active material utilization efficiency no less than 90%.

34. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said cathode active material layer contains at least 80% by weight of sulfur or metal polysulfide based on the total weight of said carbon or graphite material and said sulfur or metal polysulfide combined.

35. The rechargeable alkali metal-sulfur cell of claim 1 , wherein said cathode active material layer contains at least 90% by weight of sulfur or metal polysulfide based on the total weight of said carbon or graphite material and said sulfur or metal polysulfide combined.

36. A method of manufacturing a rechargeable alkali metal-sulfur cell of claim 1 , comprising:

(a) providing an alkali metal selected from Li, Na, K, or a combination thereof;

(b) providing a cathode containing a carbon or graphite material having expanded inter-planar spaces, d 002 from 0.43 nm to 2.0 nm, and sulfur or metal polysulfide residing in said expanded inter-planar spaces; and

(c) providing an electrolyte capable of transporting alkali metal ions.

37. The manufacturing method of claim 36 , wherein said step of providing a cathode contains impregnating said expanded inter-planar spaces with said sulfur or metal polysulfide using a vapor phase infiltration procedure, liquid solution infiltration procedure, electrochemical procedure, chemical infiltration and deposition procedure, liquid dipping procedure, or a combination thereof.

38. The manufacturing method of claim 37 , wherein said electrochemical procedure includes:

(a) preparing an electrochemical cathode layer containing a carbon or graphite material having expanded inter-planar spaces, d 002 from 0.43 nm to 2.0 nm;

(b) preparing an electrolyte comprising a non-aqueous solvent and a sulfur source dissolved or dispersed in said solvent;

(c) preparing an anode; and

(d) bringing said electrochemical cathode layer and said anode in ionic contact with said electrolyte and imposing an electric current between said anode and said electrochemical cathode layer, with a sufficient current density for a sufficient period of time to electrochemically impregnate sulfur into said expanded spaces to form said cathode active material layer.

39. The manufacturing method of claim 38 , wherein said sulfur source is selected from M x S y , wherein x is an integer from 1 to 3 and y is an integer from 1 to 10, and M is a metal element selected from an alkali metal, an alkaline metal selected from Mg or Ca, a transition metal, a metal from groups 13 to 17 of the periodic table, or a combination thereof.

40. The manufacturing method of claim 38 , wherein said anode comprises an anode active material selected from an alkali metal, an alkaline metal, a transition metal, a metal from groups 13 to 17 of the periodic table, and combinations thereof.

41. The manufacturing method of claim 39 , wherein said metal element M is selected from Li, Na, K, Mg, Zn, Cu, Ti, Ni, Co, Fe, Al, and combinations thereof.

42. The manufacturing method of claim 39 , wherein said M x S y is selected from Li 2 S 6 , Li 2 S 7 , Li 2 S 8 , Li 2 S 9 , Li 2 S 10 , Na 2 S 6 , Na 2 S 7 , Na 2 S 8 , Na 2 S 9 , Na 2 S 10 , K 2 S 6 , K 2 S 7 , K 2 S 8 , K 2 S 9 , K 2 S 10 , and combinations thereof.

43. The manufacturing method of claim 38 , wherein said electrolyte further comprises a metal salt selected from lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium borofluoride (LiBF 4 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium trifluoro-methanesulfonate (LiCF 3 SO 3 ), bis-trifluoromethyl sulfonylimide lithium (LiN(CF 3 SO 2 ) 2 ), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF 2 C 2 O 4 ), lithium nitrate (LiNO 3 ), Li-fluoroalkyl-phosphates (LiPF 3 (CF 2 CF 3 ) 3 ), lithium bisperfluoroethysulfonylimide (LiBETI), lithium bis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide, lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid-based lithium salt, sodium perchlorate (NaClO 4 ), potassium perchlorate (KClO 4 ), sodium hexafluorophosphate (NaPF 6 ), potassium hexafluorophosphate (KPF 6 ), sodium borofluoride (NaBF 4 ), potassium borofluoride (KBF 4 ), sodium hexafluoroarsenide, potassium hexafluoroarsenide, sodium trifluoro-methanesulfonate (NaCF 3 SO 3 ), potassium trifluoro-methanesulfonate (KCF 3 SO 3 ), bis-trifluoromethyl sulfonylimide sodium (NaN(CF 3 SO 2 ) 2 ), sodium trifluoromethanesulfonimide (NaTFSI), bis-trifluoromethyl sulfonylimide potassium (KN(CF 3 SO 2 ) 2 ), or a combination thereof.

44. The manufacturing method of claim 43 , wherein said solvent is selected from 1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME), tetraethylene glycol dimethylether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), diethylene glycol dibutyl ether (DEGDBE), 2-ethoxyethyl ether (EEE), sulfone, sulfolane, ethylene carbonate (EC), dimethyl carbonate (DMC), methylethyl carbonate (MEC), diethyl carbonate (DEC), ethyl propionate, methyl propionate, propylene carbonate (PC), gamma-butyrolactone (γ-BL), acetonitrile (AN), ethyl acetate (EA), propyl formate (PF), methyl formate (MF), toluene, xylene, methyl acetate (MA), fluoroethylene carbonate (FEC), vinylene carbonate (VC), allyl ethyl carbonate (AEC), a hydrofluoroether, a room temperature ionic liquid solvent, or a combination thereof.

45. The manufacturing method of claim 38 , wherein said anode, said electrolyte, and said electrochemical cathode layer are disposed in an external container outside of an alkali metal-sulfur cell and said step of electrochemically impregnating sulfur into said expanded spaces is conducted outside said alkali metal-sulfur cell.

46. The manufacturing method of claim 38 , wherein said anode, said electrolyte, and said electrochemical cathode layer are disposed inside an alkali metal-sulfur cell and said step of electrochemically impregnating sulfur into said expanded spaces is conducted after said alkali metal-sulfur cell is fabricated.