Ionic liquids for artificial sei transplantation
AssigneeToyota Motor Engineering & Manufacturing North America, Inc.
InventorsNikhilendra Singh, Timothy S. Arthur
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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.
Claims13
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 lithium and/or lithium-ion anodes by, for each SEI formation electrolyte in the library of SEI formation electrolytes, forming SEI on each lithium or lithium-ion electrode of the library by performing multiple charge/discharge cycles on the electrode in a cell having the SEI formation electrolyte;
- preparing a library of test cells by, for each protected lithiumor lithium-ion anode in the library of protected lithium and/or lithium-ion anodes, assembling a test cell comprising:
- the protected lithium or lithium-ion anode;
- and
- a wet electrolyte in contact with the 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.
The method as recited in claim 11, wherein at least one lithium salt is present at its saturation point in the ionic liquid.
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 each active material electrode of the library by performing multiple charge/discharge cycles on the active material electrode in a cell having the SEI formation electrolyte;
- preparing a library of test cells by, for each protected active material anode in the library of protected active material anodes, assembling a test cell comprising:
- the protected active material anode;
- and
- a wet electrolyte in contact with the 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.
Dependencies are inferred from the claim text.