Method of improving cycle-life of alkali metal-sulfur secondary battery

Patent metadata

Field	Value
Publication number	US-10854927-B2
Application number	US-201816010975-A
Country	US
Kind code	B2
Filing date	Jun 18, 2018
Priority date	Jun 18, 2018
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

The invention provides a method of improving the cycle-life of a rechargeable alkali metal-sulfur cell. The method comprises implementing an anode-protecting layer between an anode active material layer and a porous separator/electrolyte, and/or implementing a cathode-protecting layer between a cathode active material and the porous separator/electrolyte, wherein the anode-protecting layer or cathode-protecting layer comprises a conductive sulfonated elastomer composite having from 0.01% to 50% by weight of a conductive reinforcement material dispersed in a sulfonated elastomeric matrix material and the protecting layer has a thickness from 1 nm to 100 μm, a fully recoverable tensile strain from 2% to 500%, a lithium ion conductivity from 10−7 S/cm to 5×10−2 S/cm, and an electrical conductivity from 10−7 S/cm to 100 S/cm when measured at room temperature. This battery exhibits an excellent combination of high sulfur content, high sulfur utilization efficiency, high energy density, and long cycle life.

First claim

The invention claimed is:

1. A method of improving a cycle-life of a rechargeable alkali metal-sulfur cell, said method comprising implementing an anode-protecting layer between an anode active material layer and a porous separator/electrolyte, and/or implementing a cathode-protecting layer between a cathode active material and said porous separator/electrolyte, wherein said anode-protecting layer or cathode-protecting layer comprises a conductive sulfonated elastomer composite having from 0.01% to 50% by weight of a conductive reinforcement material dispersed in a sulfonated elastomeric matrix material and said layer of conductive sulfonated elastomer composite has a thickness from 1 nm to 100 μm, a fully recoverable tensile strain from 2% to 500%, a lithium ion conductivity from 10 −7 S/cm to 5×10 −2 S/cm, and an electrical conductivity from 10 −7 S/cm to 100 when measured at room temperature.

2. The method of claim 1 , wherein said cathode active material layer comprises a sulfur-containing material selected from the group consisting of sulfur-carbon hybrid, sulfur-graphite hybrid, sulfur-graphene hybrid, conducting polymer-sulfur hybrid, metal sulfide, sulfur compound, and combinations thereof.

3. The method of claim 2 , wherein said sulfur-carbon hybrid, sulfur-graphite hybrid, sulfur-graphene hybrid, or conducting polymer-sulfur hybrid is a mixture, blend, composite, chemically or physically bonded entity of sulfur or sulfide with a carbon, graphite, graphene, or conducting polymer material.

4. The method of claim 1 , wherein said conductive reinforcement material is selected from the group consisting of graphene sheets, carbon nanotubes, carbon nanofibers, metal nanowires, conductive polymer fibers, and combinations thereof.

5. The method of claim 1 , wherein said sulfonated elastomeric matrix material comprises a material selected from the group consisting of sulfonated versions of natural polyisoprene, synthetic polyisoprene, polybutadiene, chloroprene rubber, polychloroprene, butyl rubber, styrene-butadiene rubber, nitrile rubber, ethylene propylene rubber, ethylene propylene diene rubber, metallocene-based poly(ethylene-co-octene) elastomer. poly(ethylene-co-butene) elastomer, styrene-ethylene-butadiene-styrene elastomer, epichlorohydrin rubber, polyacrylic rubber, silicone rubber, fluorosilicone rubber, perfluoroelastomers, polyether block amides, chlorosulfonated polyethylene, ethylene-vinyl acetate, thermoplastic elastomer, protein resilin, protein elastin, ethylene oxide-epichlorohydrin copolymer, polyurethane, urethane-urea copolymer, and combinations thereof.

6. The method of claim 1 , wherein said steps (d) and (e) are conducted by depositing a layer of first sulfonated elastomer composite onto one primary surface of the anode active material layer to form a protected anode and/or depositing a layer of second sulfonated elastomer composite onto one primary surface of the cathode active material layer to form a protected cathode, followed by combining the protected anode, the separator/electrolyte, and the protected cathode together to form said alkali metal-sulfur cell.

7. The method of claim 1 , wherein said steps (d) and (e) are conducted by depositing a layer of first sulfonated elastomer composite onto one primary surface of the separator and/or depositing a layer of second sulfonated elastomer composite onto the opposing primary surface of the separator to form a coated separator, followed by combining the anode, the coated separator, the cathode, and the electrolyte together to form the alkali metal-sulfur cell.

8. The method of claim 1 , wherein said steps (d) and (e) are conducted by forming a layer of first sulfonated elastomer composite and/or a layer of second sulfonated elastomer composite, followed by laminating the anode layer, the layer of first sulfonated elastomer composite, the separator layer, the layer of second sulfonated elastomer composite, the cathode layer, along with the electrolyte to form the alkali metal-sulfur cell.

9. The method of claim 2 , wherein said metal sulfide 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.

10. The method of claim 9 , wherein said metal element M is selected from Li, Na, K, Mg, Zn, Cu, Ti, Ni, Co, Fe, or Al.

11. The method of claim 9 , wherein said metal sulfide contains Li 2 S 1 , Li 2 S 2 , Li 2 S 3 , Li 2 S 4 , Li 2 S 5 , Li 2 S 6 , Li 2 S 7 , Li 2 S 8 , Li 2 S 9 , Li 2 S 10 , Na 2 S 1 , Na 2 S 2 , Na 2 S 3 , Na 2 S 4 , Na 2 S 5 , Na 2 S 6 , Na 2 S 7 , Na 2 S 8 , Na 2 S 9 , Na 2 S 10 , K 2 S 1 , K 2 S 2 , K 2 S 3 , K 2 S 4 , K 2 S 5 , K 2 S 6 , K 2 S 7 , K 2 S 8 , K 2 S 9 , or K 2 S 10 .

12. The method of claim 2 , wherein said carbon or graphite material in said cathode active material layer is selected from the group consisting of mesophase pitch, mesophase carbon, mesocarbon microbead (MCMB), coke particle, expanded graphite flake, artificial graphite particle, natural graphite particle, highly oriented pyrolytic graphite, soft carbon particle, hard carbon particle, carbon nanotube, carbon nanofiber, carbon fiber, graphite nanofiber, graphite fiber, carbonized polymer fiber, activated carbon, carbon black, and combinations thereof.

13. The method of claim 2 , wherein said conducting polymer-sulfur hybrid comprises an intrinsically conductive polymer selected from the group consisting of polyaniline, polypyrrole, polythiophene, polyfuran, a bi-cyclic polymer, a sulfonated derivative thereof, and combinations thereof.

14. The method of claim 1 , wherein said sulfonated elastomer matrix further comprises from 0.1% to 50% by weight of a lithium ion-conducting additive or sodium ion-conducting additive dispersed therein.

15. The method of claim 14 , wherein said lithium ion-conducting additive is selected from the group consisting of Li 2 CO 3 , Li 2 O, Li 2 C 2 O 4 , LiOH, LiX, ROCO 2 Li, HCOLi, ROLi, (ROCO 2 Li) 2 , (CH 2 OCO 2 Li) 2 , Li 2 S, Li x SO y , and combinations thereof, wherein X=F, Cl, I, or Br, R=a hydrocarbon group, 0<x≤1 and 1≤y≤4.

16. The method of claim 14 , wherein said lithium ion-conducting additive is dispersed in said ultrahigh molecular weight polymer and is selected from the group consisting of lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium borofluoride (LiBF 4 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium trifluoro-metasulfonate (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 oxalyldifluoroborate (LiBF 2 C 2 O 4 ), lithium nitrate (LiNO 3 ), Li-fluoroalkyl-phosphates (LiPF 3 (CF 2 CF 3 ) 3 ), lithium bisperfluoro-ethysulfonylimide (LiBETI), lithium bis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide, lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid-based lithium salt, and combinations thereof.

17. The method of claim 14 , wherein said lithium ion-conducting polymer is selected from a lower molecular version of poly(ethylene oxide) (PEO), polypropylene oxide (PPO), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVDF), poly bis-methoxy ethoxyethoxide-phosphazene, polyvinyl chloride, polydimethylsiloxane, poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), a sulfonated derivative thereof, or a combination thereof, wherein said lower molec

Assignees

• Global Graphene Group Inc

Inventors

• Zhamu Aruna
• Jang Bor Z

Classifications

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• H01M10/0459

  Cells or batteries with folded separator between plate-like electrodes · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/052

  Li-accumulators · CPC title