Cavitand electrolytic cell and electrolytic process

• US 5,547,778 A
• Filed: 07/13/1995
• Issued: 08/20/1996
• Est. Priority Date: 07/13/1995
• 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
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US08/502,109
• Time in Patent Office: 404 Days
• Field of Search: 429/81, 429/122, 429/208, 429/216, 429/137, 429/212, 205/59, 205/57
• US Class Current: 429/81
• CPC Class Codes: H01M 10/05 Accumulators with non-aqueous electrolyte H01M10/39 takes precedence
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/24 Alkaline accumulators
• CPC Class Codes: H01M 4/02 Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/381 Alkaline or alkaline earth metals elements H01M4/40 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An electrolytic cell, such as a rechargeable lithium battery, having cavitands associated with a metal ion source-electrode and an electrolyte. The cavitands, which are anchored to the electrode by a polymer leash, are capable of releasably attracting particular ions, such as lithium ions, which are migrating from the electrolyte, toward the surface of the electrode during electrodeposition. The polymer leash serves to continuously maintain the cavitands at a predetermined distance away from the surface of the electrode, regardless of surface area fluctuations, typically caused during deposition and dissolution of the particular ions. Accordingly, the cavitands facilitate substantially uniform electrodeposition of the particular ions, which, in turn, substantially suppresses and/or controls the formation and growth of a passive film or layer, on the electrode surface, which may otherwise promote the formation of dendrites.

Claims

1. An electrolytic cell comprising:

an electrolyte;

a metal ion source electrode having an interface operatively positioned between the electrolyte and a surface of the metal ion source electrode;

a cavitand operatively associated with the electrode and the electrolyte,

the cavitand having the ability to releasably attract particular ions, associated with the metal ion source electrode, within the electrolyte;

means for anchoring the cavitand to the metal ion source electrode regardless of fluctuations to the electrode surface due to deposition, or, dissolution of the particular ions;

means for causing the release of the particular ions which have been attracted to the cavitand; and

means for directing the released ions from the cavitand toward the metal ion source electrode enabling a charge transfer reaction to occur, wherein the directed ions consequently deposit on the electrode.

2. The electrolytic cell according to claim 1, further comprising means for spacing the cavitand at least a set distance away from the metal ion source electrode.

3. The cavitand spacing means according to claim 2, including a leash having a first end associated with the cavitand and a second end associated with the metal ion source electrode.

4. The cavitand spacing means according to claim 3, wherein the second end of the leash is associated with the anchoring means.

5. The electrolytic cell according to claim 3, wherein the leash comprises a polymer which coordinates the particular ions with the leash.

6. The electrolytic cell according to claim 1, wherein the release means comprises an enhanced electric field proximate the interface, wherein the electric field is strong enough to attract the particular ions from the cavitand.

7. The electrolytic cell according to claim 6, wherein the release means comprises a layer of material associated with the surface of the metal ion source electrode, wherein the layer of material forms free radicals upon contact with the surface of the metal ion source electrode.

8. The electrolytic cell according to claim 6, wherein the release means comprises a compound selected from the group consisting of polynuclear aromatic structures, amines and ring compounds.

9. The electrolytic cell according to claim 1, wherein the released ion directing means comprises an enhanced electric field proximate the interface wherein the electric field directs the particular ions from the cavitand toward the metal ion source electrode.

10. The electrolytic cell according to claim 9, wherein the released ion directing means comprises a layer of material associated with the surface of the metal ion source electrode, wherein the layer of material forms free radicals upon contact with the surface of the metal ion source electrode.

11. The electrolytic cell according to claim 9, wherein the released ion directing means comprises a compound selected from the group consisting of polynuclear aromatic structures, amines, and ring compounds.

12. The electrolytic cell according to claim 1, wherein the cavitand includes a cavitand cavity:

the cavitand cavity including means for allowing the passage of the attracted particular ions through the cavitand cavity and, in turn, toward and from the surface of the metal ion source electrode.

13. An electrolytic process comprising the steps of:

associating a cavitand with an electrolyte;

anchoring the cavitand to a metal ion source electrode and, in turn, controlling formation and growth of a passive film, or layer, on the metal ion source electrode;

applying a voltage having a current across the electrolyte;

attracting particular ions, associated with the metal ion source electrode, within the electrolyte, to the cavitand;

enhancing an electric field adjacent a surface of the metal ion source electrode;

releasing the particular ions which have been attracted to the cavitand;

directing the released particular ions toward the metal ion source electrode as a result of the enhanced electric field; and

depositing the electrode with the particular ions.

14. The electrolytic process according to claim 13, further comprising the steps of:

spacing the cavitand at least a set distance away from the metal ion source electrode; and

maintaining the set spacing regardless of fluctuations in the surface of the metal ion source electrode due to deposition, or, dissolution.

15. The electrolytic process according to claim 13, wherein the step of releasing the particular ions from the cavitand occurs as a result of the attraction of the particular ions toward the enhanced electric field.

16. The electrolytic process according to claim 13, wherein the step of directing the particular ions from the cavitand occurs as a result of attraction of the particular ions toward the enhanced electric field.

17. The electrolytic process according to claim 13, wherein the step of enhancing an electric field adjacent the surface of the metal ion source electrode comprises the steps of:

applying a layer of material to the surface of the metal ion source electrode;

forming free radicals within the layer of material upon contact with the surface of the metal ion source electrode, to, in turn, result in the enhanced electric field.

18. The electrolytic process according to claim 13, wherein the step of releasing the particular ions from the cavitand includes the step of releasing the particular ions through the cavitand and, accordingly, toward and from the electrode.