ELECTROLYTES, CELLS AND METHODS OF FORMING PASSIVATON LAYERS

• US 20080026297A1
• Filed: 08/23/2007
• Published: 01/31/2008
• Est. Priority Date: 01/11/2005
• Status: Abandoned Application

• Current Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: Amine, Khalil, Chen, Zonghai
• Application Number:
  US11/843,889
• Publication Number:
  US 20080026297A1
• Time in Patent Office: Days
• US Class Current: 429/341
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• 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 electrolyte comprising at least one organic aprotic solvent, at least one salt and at least one chelatoborate additive. A method of forming an SEI layer in a cell comprising a positive electrode, a negative electrode and an electrolyte, said method comprising the step of overcharging the electrolyte prior to fabricating the cell, or said cell during the formation cycle.

Claims

1. An electrolyte comprising:

at least one salt of the formula;

Li_aQ

wherein Q is a borate cluster anion or heteroborate cluster anion and a is 1 or 2, at least one polar organic aprotic solvent, and at least one chelatoborate.

5. The electrolyte of claim 1 wherein the salt comprises Li₂B₁₂F_xZ_12-x wherein x is at least 5 but less than or equal to 12 and Z represents H, Cl, or Br.

6. The electrolyte of claim 1 wherein the chelatoborate comprises a lithium difluoro(oxalato)borate.

7. The electrolyte of claim 6 wherein the borate comprises LiBF₂(C₂O₄)

14. The electrolyte of claim 1 wherein the solvent comprises ethylene carbonate.

15. The electrolyte of claim 1 wherein the solvent comprises ethylmethyl carbonate.

2. A cell comprising a positive electrode, a negative electrode and an electrolyte comprising at least one borate cluster salt, at least one polar aprotic solvent and at least one lithium difluoro(oxalato)borate.

3. A cell comprising:

a positive electrode, a negative electrode and an electrolyte wherein the electrolyte comprises at least one organic aprotic carrier, at least one salt of the formula;

Li_aQ

where Q is a borate cluster anion or heteroborate cluster anion, and a is 1 or 2, and at least one additive wherein the amount of the additive is sufficient to form an SEI layer upon the negative electrode.

4. The cell of claim 3 wherein the cell is thermally stable.

8. The cell of claim 3 wherein the negative electrode comprises at least one of graphite, amorphous carbon, hard carbon, tin, silicon, and lithium titanate.

9. The cell of claim 3 wherein the positive electrode comprises at least one of LiFePO4, Li_1.1[Mn_1/3Ni_1/3Co_1/3]_0.9O₂, LiNi_1-xCo_xO₂ and lithium manganese spinel, LiMn₂O₄, LiNi_0.8Co_0.15Al_0.05O₂, LiCoO₂, LiNiO₂, and LiNi_1-x-yCo_xMn_yO₂.

10. The cell of claim 3 wherein the SEI layer comprises at least one member selected from the group consisting of alkyl carbonates, Li₂CO₃, and LiF.

11. The cell of claim 8 wherein the negative electrode comprises a carbonaceous material.

12. The cell of claim 9 wherein the positive electrode comprises Li_1.1[Mn_1/3Ni_1/3Co_1/3]_0.9O₂.

13. The cell of claim 9 wherein the positive electrode comprises LiMn₂O_4,