Electrolytes for wide operating temperature lithium-ion cells

• US 9,293,773 B2
• Filed: 06/15/2011
• Issued: 03/22/2016
• Est. Priority Date: 04/08/2008
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Smart, Marshall C., Bugga, Ratnakumar V.
• Primary Examiner(s): WEINER, LAURA S
• Application Number:
  US13/161,387
• Publication Number:
  US 20120007560A1
• Time in Patent Office: 1,742 Days
• Field of Search: 429/330, 429/331, 429/199, 429/332, 429/307, 429/231.1, 429/231.3, 429/231.8, 429/231.5, 429/231.95, 252/62.2
• US Class Current: 1/1
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 10/058 Construction or manufacture
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 2300/004 Three solvents
• CPC Class Codes: H01M 2300/0042 Four or more solvents
• 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: H01M 4/382 Lithium H01M4/405 takes precedence
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/52 of nickel, cobalt or iron
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 6/164 by the solvent
• CPC Class Codes: H01M 6/166 : by the solute
• CPC Class Codes: H01M 6/168 : by additives
• 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
• CPC Class Codes: Y10T 29/49108 : Electric battery cell making

Abstract

Provided herein are electrolytes for lithium-ion electrochemical cells, electrochemical cells employing the electrolytes, methods of making the electrochemical cells and methods of using the electrochemical cells over a wide temperature range. Included are electrolyte compositions comprising a lithium salt, a cyclic carbonate, a non-cyclic carbonate, and a linear ester and optionally comprising one or more additives.

Claims

1. An electrolyte for use in an electrochemical cell, the electrolyte comprising a mixture of:

15-30% by volume cyclic carbonate, wherein the cyclic carbonate is a combination of mono-fluoroethylene carbonate (FEC) and EC wherein the FEC is present in an amount from 0.5 to 10% by volume;

15-30% by volume non-cyclic carbonate, wherein the non-cyclic carbonate is selected from ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl propyl carbonate (MPC) and combinations thereof;

40-70% by volume non-fluorinated linear ester, wherein the non-fluorinated linear ester is selected from;

methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, and combinations thereof; and

a lithium salt in a concentration from 0.5 M to 1.5 M.

2. The electrolyte of claim 1, wherein the non-cyclic carbonate is ethyl methyl carbonate (EMC), the lithium salt includes LiPF₆ in a concentration from 0.8 to 1.20 M and the non-fluorinated linear ester is selected from methyl propionate, methyl butyrate and combinations thereof.

3. The electrolyte of claim 1, wherein at least two non-fluorinated linear esters are present, a first non-fluorinated linear ester having a low viscosity and selected from the group consisting of methyl propionate, ethyl propionate, methyl butyrate and ethyl butyrate and a second non-fluorinated linear ester having a high viscosity and selected from the group consisting of propyl butyrate and butyl butyrate.

4. The electrolyte of claim 1 further comprising an additive selected from lithium oxalate, lithium bis(oxalato)borate (LiBOB), vinylene carbonate (VC), lithium difluoro(oxolato) borate (LiDFOB) and combinations thereof.

5. The electrolyte of claim 1 further comprising an additive selected from lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxolato) borate (LiDFOB) and combinations thereof in a concentration of 0.05 to 0.25 M.

6. The electrolyte of claim 1 wherein the FEC is present in an amount from 2 to 10% by volume.

7. The electrolyte of claim 1 wherein the FEC is present in an amount from 0.5 to 5% by volume.

8. An electrochemical cell comprising:

an anode;

a cathode; and

the electrolyte of claim 1 provided between the anode and the cathode.

9. The electrochemical cell of claim 8, wherein the cathode comprises a material selected from LiCoO₂, LiMn₂O₄, LiMPO₄ (M=Fe, Co, Mn), LiNiCoAlO₂, LiNi_0.33CO_0.33Mn_0.33O₂, LiNiCoO₂, LiNi_0.8Co_0.2O₂, Li(Li_0.17Ni_0.25Mn_0.58)O₂, layered-layered composite LiNiCoMnO₂ or LiNi_0.5Mn_1.5O₄.

10. The electrochemical cell of claim 8, wherein the anode comprises a material selected from natural graphite, synthetic graphite, hard carbon, mesocarbon microbeads (MCMB), silicon-carbon composites, lithium titanate (Li₄Ti₅O₁₂), lithium metal and combinations thereof.

11. The electrochemical cell of claim 8 wherein the anode is a carbon-based anode and the cathode is selected from LiFePO₄, LiNiCoO₂, LiNiCoAlO₂, and a layered-layered composite of LiNiCoMnO₂, LiNi_0.5Mn_1.5O₄ or Li Ni_0.33Co_0.33Mn_0.33O₂.

12. A method of making an electrochemical cell comprising the steps of:

providing a cathode;

providing an anode; and

providing the electrolyte of claim 1 between the cathode and the anode.

13. A method of generating an electrical current, the method comprising the steps of:

providing an electrochemical cell according to claim 8, the cell being in a charged state; and

discharging the electrochemical cell.