ELECTROLYTES FOR LITHIUM ION BATTERIES

• US 20180108937A1
• Filed: 12/18/2017
• Published: 04/19/2018
• Est. Priority Date: 04/07/2016
• Status: Active Grant

• Current Assignee: StoreDot Ltd.
• Original Assignee: StoreDot Ltd.
• Inventors: Drach, Zohar, Guchok, Olga, Krasovitsky, Leonid
• Granted Patent: US 10,199,677 B2
• Time in Patent Office: Days
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 2300/0051 Carbonates
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Electrolytes, lithium ion cells and corresponding methods are provided, for extending the cycle life of fast charging lithium ion batteries. The electrolytes are based on fluoroethylene carbonate (FEC) and/or vinylene carbonate (VC) as the cyclic carbonate component, and possibly on ethyl acetate (EA) and/or ethyl methyl carbonate (EMC) as the linear component. Proposed electrolytes extend the cycle life by factors of two or more, as indicated by several complementary measurements.

Claims

1. A lithium ion cell comprising an electrolyte having at least one linear component and at least one cyclic carbonate component, wherein the at least one cyclic carbonate component comprises at least 80% of fluoroethylene carbonate (FEC) and/or vinylene carbonate (VC), and wherein the electrolyte comprises at least 20% vol of FEC and/or VC and further comprises at least one lithium salt.

2. The lithium ion cell of claim 1, wherein the at least one linear component comprises any of:

ethyl acetate (EA), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), modified linear carbonates and fluorinated linear carbonates.

3. The lithium ion cell of claim 1, wherein the at least one linear component comprises at least 30% of at least one of:

ethyl acetate (EA), propyl acetate and propionates.

4. The lithium ion cell of claim 1, wherein a volume ratio between the at least one cyclic carbonate component and the at least one linear component is between 2:

8 and 1;

1.

5. The lithium ion cell of claim 1, wherein the electrolyte comprises, as the at least one linear component, at least 20% vol EA, propyl acetate and/or propionates, and at least 50% vol EMC.

6. The lithium ion cell of claim 1, wherein the electrolyte comprises between 20-40% vol FEC, between 20-40% vol EA and between 20-60% vol EMC.

7. The lithium ion cell of claim 1, wherein the electrolyte further comprises at least one lithium electrolyte salt and any of:

esters-based solvents, sulfones-based solvents, nitriles-based solvents, ethers-based solvents, alcohol-based solvents, hydrocarbons, aprotic-based solvents, a SEI forming additive, a HF scavenger additive, a phosphorous-containing compounds and mixtures thereof.

8. The lithium ion cell of claim 1, wherein the electrolyte consists of 20-40% vol FEC and/or VC, 20-40% vol EA and 40-60% vol EMC and 0.9-1.3M LiPF₆.

9. The lithium ion cell of claim 1, wherein an anode thereof comprises Si, Ge, Sn and/or LTO (lithium titanate)-based anode active material.

10. An energy storage device comprising the lithium ion cell of claim 1.

11. A method comprising using an electrolyte in a lithium ion cell, wherein all or most cyclic carbonates are FEC and/or VC and wherein all or most linear components are EA and/or EMC.