Protective lithium ion conducting ceramic coating for lithium metal anodes and associate method

• US 5,314,765 A
• Filed: 10/14/1993
• Issued: 05/24/1994
• Est. Priority Date: 10/14/1993
• Status: Expired due to Term

• Current Assignee: Martin Marietta Energy Systems, Inc.
• Original Assignee: Martin Marietta Energy Systems, Inc.
• Inventors: Bates, John B.
• Primary Examiner(s): Skapars, Anthony
• Application Number:
  US08/137,285
• Time in Patent Office: 222 Days
• Field of Search: 429/218, 429/194, 429/48, 429/197, 29/623.5
• US Class Current: 429/231.95
• CPC Class Codes: H01M 10/05 Accumulators with non-aqueous electrolyte H01M10/39 takes precedence
• CPC Class Codes: H01M 2004/028 Positive electrodes
• 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: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 50/431 Inorganic material
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

A battery structure including a cathode, a lithium metal anode and an electrolyte disposed between the lithium anode and the cathode utilizes a thin-film layer of lithium phosphorus oxynitride overlying so as to coat the lithium anode and thereby separate the lithium anode from the electrolyte. If desired, a preliminary layer of lithium nitride may be coated upon the lithium anode before the lithium phosphorous oxynitride is, in turn, coated upon the lithium anode so that the separation of the anode and the electrolyte is further enhanced. By coating the lithium anode with this material lay-up, the life of the battery is lengthened and the performance of the battery is enhanced.

Claims

1. In a battery including a cathode, a lithium anode, and an electrolyte interposed between the cathode and anode, the improvement comprising:

a protective film including a layer of lithium phosphorus oxynitride overlying and coating the lithium anode so that the lithium anode is separated from the electrolyte by the lithium phosphorus oxynitride layer.

2. The improvement as defined in claim 1 wherein the thickness of the layer of lithium phosphorus oxynitride of the protective film is between about 0.1 and 0.5 μ

m.

3. The improvement as defined in claim 1 wherein the protective film further includes a layer of lithium nitride (Li₃ N) disposed between the surface of the lithium anode and the layer of lithium phosphorus oxynitride.

4. The improvement as defined in claim 3 wherein the thickness of the layer of lithium nitride of the protective film is between about 0.05 and 0.1 μ

m.

5. The improvement as defined in claim 4 wherein the thickness of the layer of lithium phosphorus oxynitride of the protective film is between about 0.1 and 0.5 μ

m.

6. A battery structure comprising:

a cathode;

a lithium anode;

an electrolyte disposed between the cathode and the lithium anode; and

a layer of lithium phosphorus oxynitride overlying and coating the lithium anode so that the lithium anode is prevented from contacting the electrolyte by the lithium phosphorus oxynitride layer.

7. The structure as defined in claim 6 wherein the thickness of the layer of lithium phosphorus oxynitride of the protective film is between about 0.1 and 0.5 μ

m.

8. The improvement as defined in claim 6 wherein the protective film further includes a layer of lithium nitride (Li₃ N) disposed between the surface of the lithium anode and the layer of lithium phosphorus oxynitride.

9. The improvement as defined in claim 6 wherein the thickness of the layer of lithium nitride of the protective film is between about 0.05 and 0.1 μ

m.

10. The structure as defined in claim 9 wherein the thickness of the layer of lithium phosphorus oxynitride of the protective film is between about 0.1 and 0.5 μ

m.

11. In a battery-forming operation involving the positioning of a lithium anode and an electrolyte material adjacent to one another, the improvement comprising:

coating the lithium anode by depositing a film of lithium phosphorus oxynitride over and coating the lithium anode prior to the positioning of the lithium anode and electrolyte material adjacent one another so that when the lithium anode and electrolyte material are positioned adjacent one another in the resultant battery, the lithium phosphorous oxynitride is interposed between the lithium anode and the electrolyte.

12. The improvement as defined in claim 11 wherein the depositing step effects the formation of a lithium phosphorus oxynitride film having a thickness of between about 0.1 and 0.5 μ

m.

13. The improvement as defined in claim 11 wherein the step of depositing a film of lithium phosphorus oxynitride is preceded by a step of depositing a film of lithium nitride (Li₃ N) over so as to coat the lithium anode so that the subsequent step of depositing the film of lithium phosphorus oxynitride coats the Li₃ N with the lithium phosphorus oxynitride film.

14. The improvement as defined in claim 13 wherein the step of depositing the film of Li₃ N effects the formation of the Li₃ N film having a thickness of between about 0.05 and 0.1 μ

m.

15. The improvement as defined in claim 14 wherein the step of depositing a film of lithium phosphorus oxynitride effects the formation of the lithium phosphorus film of between about 0.1 and 0.5 μ

m.