Ionic liquids for artificial SEI transplantation

Patent metadata

Field	Value
Publication number	US-11335959-B2
Application number	US-201916527994-A
Country	US
Kind code	B2
Filing date	Jul 31, 2019
Priority date	May 26, 2017
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

An anode for a lithium or lithium-ion cell, protected with an SEI by pre-treatment in an SEI-formation cell, is stable for cell cycling even in the presence of substantial water in the cell electrolyte. A method for making the protected anode includes forming an SEI on a lithium or lithium-ion electrode by performing multiple charge/discharge cycles on the electrode in a first cell having an SEI formation electrolyte to produce the protected anode. The SEI formation electrolyte includes an ionic liquid having at least one of eight organic cations.

First claim

What is claimed is:

1. A method for optimizing an Artificial SEI Transplantation (AST) system, the method comprising:
providing a library of SEI formation electrolytes, each electrolyte in the library having at least one lithium salt and at least one ionic liquid;
preparing a library of protected anodes by, for each of the SEI formation electrolytes in the library of SEI formation electrolytes, forming SEI on an anode in a cell having a respective SEI formation electrolyte such that the protected anodes are prepared, wherein the protected anodes consist of at least one of protected lithium anodes and protected lithium-ion anodes;
preparing a library of wet test cells by, for each of the protected anodes in the library of protected anodes, assembling a wet test cell comprising:
one of the protected anodes; and
a wet electrolyte in contact with the one protected anode, the wet electrolyte comprising at least 50 ppm water;

measuring an electrochemical property of each wet test cell in the library of test cells; and
selecting an SEI formation electrolyte on the basis of the measured electrochemical property.

2. The method as recited in claim 1 , wherein each of the at least one lithium salts is selected from the group consisting of:
lithium bis(fluorosulfonyl)imide (LiFSI),
lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and
lithium dicyanamide (LiDCA); and

and each of the at least one ionic liquids comprises:
a cation selected from the group consisting of: 1-methyl-1-propylpyrrolidinium (Pyr13); N-methyl-N,N-diethyl-N-propylammonium (N1223); N,N-diethyl-N-methyl-N-(2-methoxyethyl)-ammonium (DEME); 1,1-methylpropylpiperidinium (Pip13); N-methyl-N-(2-methoxyethyl)-pyrrolidinium (Pyr12 o 1); trimethylisopropylphosphonium (P111 i 4); methyltriethylphosphonium (P1222); methyltributylphosphonium (P1444); N,N-dimethyl-N-(2-methoxyethyl)-N-ethyl-ammonium (DMME); 1-methyl-1-butylpyrrolidinium (Pyr14); N-methyl-N′-ethylimidazolium (IM12); N,N,N-trimethyl-N-propylammonium (N1113); and mixtures thereof; and
an anion selected from the group consisting of FSI, TFSI, and DCA.

3. The method as recited in claim 1 , wherein at least one SEI formation electrolyte has the at least one lithium salt present at a molar ratio, relative to ionic liquid of: at least 1:1.

4. The method as recited in claim 1 , further comprising, prior to assembling each wet test cell, washing each protected anode with a solvent in which the SEI formation electrolyte is soluble.

5. The method as recited in claim 1 , wherein at least one wet electrolyte comprises water present at a concentration of at least 100 ppm.

6. The method as recited in claim 1 , wherein at least one wet electrolyte comprises water present at a concentration of at least 500 ppm.

7. The method as recited in claim 1 , wherein at least one wet electrolyte comprises water present at a concentration of at least 1000 ppm.

8. The method as recited in claim 1 , wherein at least one wet electrolyte comprises water present at a concentration of at least 4000 ppm.

9. The method as recited in claim 1 , wherein at least one wet electrolyte comprises water present at a concentration of at least 16000 ppm.

10. The method as recited in claim 1 , wherein the at least one lithium salt is present at its saturation point in the at least one ionic liquid.

11. A method for optimizing an Artificial SEI Transplantation (AST) system, the method comprising:
providing a library of SEI formation electrolytes, each electrolyte in the library having:
an active cation salt comprising:
an active cation; and
an anion selected from the group consisting of:
lithium bis(fluorosulfonyl)imide (LiFSI),
lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and
lithium dicyanamide (LiDCA); and

at least one ionic liquid;

preparing a library of protected active material anodes configured to incorporate the active cation in metallic or cationic form, by forming, for each SEI formation electrolyte in the library of SEI formation electrolytes, an SEI on an active material anode by performing multiple charge/discharge cycles on the active material anode in a cell having a respective SEI formation electrolyte such that that the protected active material anodes are prepared;
preparing a library of wet test cells by, for each of the protected active material anodes in the library of protected active material anodes, assembling a test cell comprising:
one of the protected active material anodes; and
a wet electrolyte in contact with the one protected active material anode, the wet electrolyte comprising at least 50 ppm water;

measuring an electrochemical property of each wet test cell in the library of test cells; and
selecting an SEI formation electrolyte on the basis of the measured electrochemical property.

12. The method as recited in claim 11 , wherein the active cation is selected from the group consisting of magnesium, sodium, and calcium.

13. The method as recited in claim 11 , wherein the at least one ionic liquid comprises a cation selected from the group consisting of: 1-methyl-1-propylpyrrolidinium (Pyr13); N-methyl-N,N-diethyl-N-propylammonium (N1223); N,N-diethyl-N-methyl-N-(2-methoxyethyl)-ammonium (DEME); 1,1-methylpropylpiperidinium (Pip13); N-methyl-N-(2-methoxyethyl)-pyrrolidinium (Pyr12 o 1); trimethylisopropylphosphonium (P111 i 4); methyltriethylphosphonium (P1222); methyltributylphosphonium (P1444); N,N-dimethyl-N-(2-methoxyethyl)-N-ethyl-ammonium (DMME); 1-methyl-1-butylpyrrolidinium (Pyr14); N-methyl-N′-ethylimidazolium (IM12); N,N,N-trimethyl-N-propylammonium (N1113); and mixtures thereof.

Assignees

• Toyota Eng & Mfg North America
• Univ Deakin

Inventors

• Singh Nikhilendra
• Arthur Timothy S
• Takechi Kensuke
• Howlett Patrick
• Forsyth Maria
• Kerr Robert

Classifications

• H01M10/0569

  characterised by the solvents · CPC title

• H01M2300/0045

  Room temperature molten salts comprising at least one organic ion · CPC title

• H01M10/4235 Primary

  Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence) · CPC title

• H01M10/0568

  characterised by the solutes · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title