Electrochemical cells with catholyte additives and lithium-stuffed garnet separators

Patent metadata

Field	Value
Publication number	US-2021399338-A1
Application number	US-201917289272-A
Country	US
Kind code	A1
Filing date	Nov 5, 2019
Priority date	Nov 6, 2018
Publication date	Dec 23, 2021
Grant date	—

Abstract

Set forth herein are processes for making and using electrolytes (also known as catholytes when the electrolytes are mixed with cathode active materials) for a positive electrode of an electrochemical cell. The catholytes include additives that prevent surface fluorination of lithium-stuffed garnet solid-state separators in contact with the positive electrode. Also set forth herein are electrochemical devices which include the catholytes in addition to a lithium-stuffed garnet solid-state electrolyte separator.

First claim

What is claimed is:

1 . An electrochemical cell comprising, a positive electrode, a negative electrode, and a solid-state electrolyte therebetween;
wherein the positive electrode comprises a catholyte comprising:
a lithium salt;
a first solvent selected from the group consisting of sulfolane, 1,3-propane sultone, sulfolene, thiophene, and combinations thereof;
a second solvent; and
a strong Lewis acid;
wherein the solid-state electrolyte comprises lithium-stuffed garnet; and wherein the negative electrode comprises lithium metal.

2 . The electrochemical cell of claim 1 , wherein the solid-state electrolyte is a thin film.

3 . The electrochemical cell of claim 1 or 2 , wherein the lithium salt is selected from the group consisting of LiPF 6 , lithium bis(perfluoroethanesulfonyl)imide (LIBETI), bis(trifluoromethane)sulfonimide (LiTFSI), LiBF 4 , LiAsF 6 , lithium bis(fluorosulfonyl)imide (LiFSI), and combinations thereof.

4 . The electrochemical cell of any one of claims 1 - 3 , wherein the lithium salt is present at a concentration of about 0.5 M to about 2.0 M.

5 . The electrochemical cell of any one of claims 1 - 4 , wherein the second solvent is selected from dimethyl carbonate (DMC), ethyl-methyl carbonate (EMC), propylmethyl carbonate, nitroethyl carbonate, propylene carbonate (PC), diethyl carbonate (DEC), methyl propyl carbonate (MPC), 2,5-dioxahexanedioic acid dimethyl ester, tetrahydrofuran (THF), γ-butyrolactone (GBL), gamma butyl-lactone, fluoroethylene carbonate (FEC), fluoromethyl ethylene carbonate (FMEC), trifluoroethyl methyl carbonate (F-EMC), fluorinated 3-(1,1,2,2-tetrafluoroethoxy)-1,1,2,2-tetrafluoropropane/1,1,2,2-tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)propane (F-EPE), fluorinated cyclic carbonate (F-AEC), dioxolane, prop-1-ene-1,3-sultone (PES), sulfolane, acetonitrile (ACN), succinonitrile (SCN), pimelonitrile, suberonitrile, propionitrile, propanedinitrile, glutaronitrile (GLN), adiponitrile (ADN), hexanedinitrile, pentanedinitrile, acetophenone, isophorone, benzonitrile, ethyl propionate, methyl propionate, methylene methanedisulfonate, dimethyl sulfate, dimethyl sulfoxide (DMSO), ethyl acetate, methyl butyrate, dimethyl ether (DME), diethyl ether, dioxolane, methyl benzoate, 2-methyl-5-oxooxolane-2-carbonitrile, and combinations thereof.

6 . The electrochemical cell any one of claims 1 - 5 , wherein the ratio of the second solvent to the first solvent is from 30:70 vol/vol to 50:50 v/v.

7 . The electrochemical cell of any one of claims 1 - 6 , wherein the strong Lewis acid is a trivalent phosphite, phosphate, or borate compound.

8 . The electrochemical cell of claim 7 , wherein the strong Lewis acid is selected from the group consisting TTSPi and TTSP.

9 . The electrochemical cell of claim 1 , wherein the strong Lewis acid comprises 1 wt % MMDS and 1 wt % TTSPi.

10 . The electrochemical cell of claim 1 , wherein the catholyte comprises 1.4 M LiPF 6 , 45 v/v EC, 50 v/v sulfolane, and 5 v/v dibutylsulfone.

11 . The electrochemical cell of any one of claims 1 - 10 , wherein the strong Lewis acid is present at 0.2 wt % to 5 wt %, where the wt % is based on the total net mass of the salt plus solvent mixture.

12 . The electrochemical cell of any one of claims 1 - 11 , wherein the lithium-stuffed garnet is characterized by a formula selected from the group consisting of Li A La B M′ C M″ D Zr E O F , Li A La B M′ C M″ D Ta E O F , and Li A La B M′ C M″ D Nb E O F , wherein 4<A<8.5, 1.5<B<4, 0≤C<2, 0≤D<2; 0<E<2, 10<F<14, and wherein M′ and M″ are each, independently, selected from the group consisting of Al, Mo, W, Nb, Ga, Sb, Ca, Ba, Sr, Ce, Hf, Rb, and Ta.

13 . The electrochemical cell of any one of claims 1 - 11 , wherein the lithium-stuffed garnet is characterized by a formula selected from the group consisting of Li a La b Zr c Al d Me″ e O f wherein 5<a<7.7; 2<b<4; 0<c<2.5; 0<d<2; 0≤e<2, 10<f<14, and wherein Me″ is a metal selected from the group consisting of Nb, Ta, V, W, Mo, and Sb.

14 . A process for making an electrochemical cell, comprising:
providing a positive electrode infiltrated with a catholyte, the catholyte comprising:
a lithium salt;
a first solvent selected from the group consisting of sulfolane, 1,3-propane sultone, sulfolene, thiophene, and combinations thereof;
a second solvent; and
a strong Lewis acid;
providing a sintered lithium-stuffed garnet solid-state separator; and contacting the sintered lithium-stuffed garnet solid-state separator to the positive electrode.

15 . A method of using an electrochemical cell of any one of claims 1 - 13 , comprising holding the electrochemical cell at a voltage of 3.9 V (v. Li) or greater.

16 . The method of claim 15 , wherein the voltage is less than 5V (v. Li).

17 . The method of claim 15 , further comprising charging and discharging the electrochemical cell between 0 and 4.5 V.

18 . An electrochemical cell made by the process of claim 14 .

19 . A rechargeable battery comprising the electrochemical cell of any one of claims 1 - 13 .

20 . An electric vehicle comprising the rechargeable battery of claim 19 .

Assignees

• Quantumscape Battery Inc

Inventors

• Arnold Thomas
• Beck Larry
• Ho Tiffany
• Yang Aram

Classifications

• Y02E60/50

  Fuel cells · CPC title

• H01M4/48

  of inorganic oxides or hydroxides · CPC title

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M2300/0071

  Oxides · CPC title

• H01M10/0525

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