Electrolytes for lithium ion batteries

• US 10,199,677 B2
• Filed: 12/18/2017
• Issued: 02/05/2019
• Est. Priority Date: 04/07/2016
• Status: Active Grant

• Current Assignee: StoreDot Ltd.
• Original Assignee: StoreDot Ltd.
• Inventors: Drach, Zohar, Guchok, Olga, Krasovitsky, Leonid, Gotlib Vainshtein, Ekaterina, Amir, Liron
• Primary Examiner(s): Gatewood, Daniel S
• Application Number:
  US15/844,689
• Publication Number:
  US 20180108937A1
• Time in Patent Office: 414 Days
• Field of Search: None
• 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:

at least one anode comprising anode active material which consists of Si, Ge and/or Sn,

at least one cathode, and

an electrolyte consisting of at least one solvent, at least one linear carbonate component, at least one cyclic carbonate component, at least one lithium salt and optional additives up to 2%,

wherein the at least one cyclic carbonate component comprises at least 20% vol of vinylene carbonate (VC),

and

wherein the lithium ion cell is configured to operate at a fast charging rate of at least 10C, and

wherein the electrolyte has a 3;

7 ratio between the VC and the at least one linear carbonate component.

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

5. The lithium ion cell of claim 1, wherein the at least one solvent comprises 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.

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

7. A method comprising using an electrolyte in a lithium ion cell which comprises at least one anode with anode active material consisting of Si, Ge and/or Sn the lithium ion cell configured to operate at a fast charging rate of at least 10C, wherein all or most cyclic carbonates are VC, wherein the VC makes up 30% of the electrolyte, and wherein all or most linear carbonate components are EA and/or EMC.

8. A lithium ion cell comprising:

at least one anode comprising anode active material which consists of Si, Ge and/or Sn,

at least one cathode, and

an electrolyte consisting of at least one linear carbonate component, at least one cyclic carbonate component, at least one lithium salt and optional additives up to 2%,

wherein the at least one cyclic carbonate component comprises at least 20% vol of vinylene carbonate (VC) and/or fluoroethylene carbonate (FEC), and

wherein the lithium ion cell is configured to operate at a fast charging rate of at least 10C, and

wherein the electrolyte is selected from 1-1.3M LiPF₆ in FEC;

DMC (1;

1) and 2 wt % VC;

1M LiPF₆ in FEC;

DMC (3;

7) and 2 wt % VC;

1M LiPF₆ in FEC;

DMC (3;

7), 2 wt % VC and 10 wt % EC;

1M LiPF₆ in FEC;

DEC (3;

7) and 2 wt % VC;

1M LiPF₆ in FEC;

EMC (3;

7) and 2 wt % VC;

1M LiPF₆ in FEC;

PC;

EMC (2;

3;

5) and 2 wt % VC;

1M LiPF₆ in FEC;

DMC (1;

1), 2% VC, 10 wt % TMP (trimethyl phosphate) and 0.05M LIFOB (lithium difluoro(oxalato)borate);

1M LiPF₆ in FEC;

DMC (1;

1), 2 wt % VC, 10 wt % TMP and 0.5 wt % TMSP (tris(trimethylsilyl)phosphite);

1M LiPF₆ in FEC;

DMC (1;

1), 2 wt % VC, 10 wt % TMP, 0.05M LIFOB and 0.5 wt % TMSP;

1M LiPF₆ in FEC;

DMC (1;

1), 2 wt % VC, 10 wt % TMP, and 0.05M LIBOB (lithium bis(oxalato)borate);

1M LiPF₆ in FEC;

DMC (1;

1), 2 wt % VC 10 wt % TMP 1 wt % DPDMS (diphenyldimethoxysilane);

1M LiPF₆ in FEC;

EMC (3;

7), 2 wt % VC and 10 wt % TMP;

1M LiPF₆ in FEC;

EMC (3;

7), 2 wt % VC and 10 wt % MFE (methylperfluorobutylether);

1M LiPF₆ in FEC;

DMC (3;

7), 2 wt % VC and 10 wt % TMP;

1M LiPF₆ in FEC;

DMC (1;

1), 2 wt % VC and 10 wt % TMP;

1M LiPF₆ in FEC;

EMC (2.5;

7.5) and 1.5 wt % VC;

1M LiPF₆ in FEC;

EMC;

DMC (2.5;

6.5;

1) and 0.5 wt % VC;

1M LiPF₆ in VC;

EA (ethylene acetate);

EMC (3;

3.5;

3.5);

1M LiPF₆ in VC;

EMC (3;

7); and

1M LiPF₆ FEC;

EMC (3;

7).

9. The lithium ion cell of claim 8, wherein the electrolyte is selected from 1.3M LiPF6 in FEC:

DMC (1;

1) and 2 wt % VC;

1M LiPF6 in FEC;

DEC (3;

7) and 2 wt % VC;

1M LiPF6 in FEC;

DMC (1;

1), 2 wt % VC, 10 wt % TMP and 0.5 wt % TMSP (tris(trimethylsilyl)phosphite);

1M LiPF6 in FEC;

DMC (1;

1), 2 wt % VC and 10 wt % TMP;

1M LiPF6 in FEC;

EMC (2.5;

7.5) and 1.5 wt % VC;

1M LiPF6 in FEC;

EMC;

DMC (2.5;

6.5;

1) and 0.5 wt % VC;

1M LiPF6 in VC;

EA (ethylene acetate);

EMC (3;

3.5;

3.5);

1M LiPF6 in VC;

EMC (3;

7); and

1M LiPF6 FEC;

EMC (3;

7).

10. A lithium ion cell comprising:

at least one anode comprising anode active material which consists of Si, Ge and/or Sn,

at least one cathode, and

an electrolyte consisting of at least one linear carbonate component, at least one cyclic carbonate component, at least one lithium salt and optional additives up to 2%,

wherein the at least one cyclic carbonate component comprises at least 20% vol of vinylene carbonate (VC), and

wherein the lithium ion cell is configured to operate at a fast charging rate of at least 10C, and

wherein the electrolyte consists of 0.9-1.3M LiPF₆ in 20-40% vol VC and one of;

20-40% vol EA, 20-40% vol EA, 40-60% vol EMC or 80-60% vol EMC, wherein the VC and EA and/or EMC add up to 100%.