Secondary electrolytic cell and electrolytic process

• US 5,434,021 A
• Filed: 08/12/1994
• Issued: 07/18/1995
• Est. Priority Date: 08/12/1994
• Status: Expired due to Term

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Arthur D. Little, Inc.
• Inventors: Shi, Jie, Fauteux, Denis G., Van Buren, Martin, Rona, Mehmet
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Mee, Brendan
• Application Number:
  US08/290,017
• Time in Patent Office: 340 Days
• Field of Search: 429/216, 429/212, 429/213
• US Class Current: 429/213
• CPC Class Codes: H01M 10/05 Accumulators with non-aqueous electrolyte H01M10/39 takes precedence
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

An electrolytic cell and electrolytic process wherein the cell includes a metal anode (such as a lithium anode), a cathode and an electrolyte. A surface layer which is applied to the metal anode enables transfer of ions from the metal anode to the electrolyte and thus allows the ions to pass back into contact with the metal anode. The surface layer is also electronically conductive so that the ions will be uniformally attracted back onto the metal anode during electrodeposition to, in turn, substantially suppress dendrite growth and, in turn, substantially increase the cycle life of the cell.

Claims

1. An electrolytic cell comprising:

an anode having an interface, a cathode and an electrolyte;

a surface layer applied to the interface of the anode, wherein the surface layer is constructed from a material which is in an initial state of substantial chemical equilibrium with the anode

the surface layer having

means for enabling transfer of ions from the anode to the electrolyte and back into contact with the anode, and, means for providing electronic conductivity in the surface layer upon formation of dendritic growth on the interface, to, in turn, substantially suppress the dendritic growth, so as to result in a substantially uniform distribution of metal ions back onto the anode during electrodeposition,

the surface layer returning to its initial state of substantial chemical equilibrium after the substantial suppression of the dendritic growth.

2. The electrolytic cell according to claim 1 wherein the anode is substantially constructed from an alkali metal.

3. The electrolytic cell according to claim 2 wherein the anode is lithium.

4. The electrolytic cell according to claim 2 wherein the surface layer includes a polymer comprising a polynuclear aromatic structure.

5. The electrolytic cell accordingly to claim 4 wherein the polynuclear aromatic structure comprises vinylnaphthalene.

6. The electrolytic cell according to claim 2 wherein the surface layer includes a polymerized alkene which is substituted with a polynuclear aromatic structure.

7. The electrolytic cell according to claim 1 wherein the surface layer includes a polymerized alkene which is substituted with atoms selected from the group comprising nitrogen, oxygen, sulfur and phosphorus.

8. The electrolytic cell according to claim 1 wherein the surface layer includes polyethylene oxide.

9. The electrolytic cell according to claim 1 wherein the surface layer comprises a copolymer of an alkene monomer substituted with a polynuclear aromatic structure and an alkene monomer substituted with atoms selected from the group of nitrogen, oxygen, sulfur and phosphorus.

10. An electrolytic cell comprising:

an anode having an interface, a cathode and an electrolyte; and

a surface layer applied to the interface of the anode,

the surface layer including a copolymer which enables transfer of ions from the anode to the electrolyte and back into operable contact with the anode, and, which becomes electronically conductive upon formation of dendritic growth at the interface.

11. The invention according to claim 10 wherein the anode is lithium, and the surface layer comprises a copolymer of polyvinylnaphthalene and polyethylene oxide.

12. A rechargeable battery comprising:

a metal anode having an interface, a cathode and an electrolyte;

means for substantially suppressing dendritic growth on the interface of the metal anode during electrodeposition,

the means for substantially suppressing dendritic growth including a surface layer applied to the interface of the metal anode, wherein the surface layer is constructed from a material which is in an initial state of substantial chemical equilibrium with the metal anode,

the surface layer having

means for enabling transfer of ions from the metal anode to the electrolyte and back into operable contact with the metal anode, and, means for providing electronic conductivity in the surface layer upon formation of dendritic growth on the interface to, in turn, substantially suppress the dendritic growth, so as to result in a substantially uniform attraction of metal ions back onto the metal anode during electrodeposition,

the surface layer returning to its initial state of substantial chemical equilibrium after the substantial suppression of the dendritic growth.

13. The rechargeable battery according to claim 12 wherein the metal anode is constructed from an alkali metal.

14. The rechargeable battery according to claim 12 wherein the surface layer includes a polymer comprising a polynuclear aromatic structure.

15. The rechargeable battery according to claim 12 wherein the surface layer includes a polymerized alkene which is substituted with atoms selected from the group comprising nitrogen, oxygen, sulfur and phosphorous.

16. The rechargeable battery according to claim 12 wherein the surface layer comprises a copolymer of an alkene monomer substituted with a polynuclear aromatic structure and an alkene monomer substituted with atoms from the group comprising nitrogen, oxygen, sulfur and phosphorous.

17. An electrolytic process comprising the steps of:

connecting two electrodes separated and positioned within an electrolyte,

at least one of the two electrodes being an anode substantially constructed from an alkali metal and wherein the anode is at least partially coated with a surface layer;

producing an electric field from the anode interface into the electrolyte;

attracting alkali metal ions from the anode interface and through the surface layer;

electrodepositing the alkali metal ions onto the alkali metal anode;

conducting electrons in the surface layer upon formation of radical anions at an interface between the surface layer and the alkali metal anode upon formation of dendritic growth;

maintaining the conductivity of electrons until the dendritic growth is substantially suppressed;

returning the surface layer to a state of substantial chemical equilibrium after dendritic growth has been substantially suppressed.

18. The electrolytic process according to claim 17 wherein the surface layer includes a polymer comprising a polynuclear aromatic structure;

the step of conducting electrons in the surface layer comprises the step of producing radical anions upon contact between the polynuclear aromatic structure and the dendritic growth on the alkali metal anode.

19. The electrolytic process according to claim 17 wherein the surface layer includes an ion transferring polymer;

the process further comprising

the step of transferring ions from the alkali metal anode through the surface layer and into operable contact with the electrolyte wherein said step of transferring ions comprises complexing the ion transferring polymer with the alkali metal anode ions at the interface of the surface layer and the alkali metal anode.

20. The electrolytic process according to claim 17 wherein the alkali metal anode is lithium.