Electrochemical cells having ionic liquid-containing electrolytes

Patent metadata

Field	Value
Publication number	US-10673095-B2
Application number	US-201715702997-A
Country	US
Kind code	B2
Filing date	Sep 13, 2017
Priority date	Sep 13, 2017
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

Electrolytes and electrochemical cells include a novel ionic liquid having a quaternary cation and a boron cluster anion. In some versions, the boron cluster anion will be a functionalized or unfunctionalized icosahedral boranyl or carboranyl anion. Electrochemical cells have an electrolyte including the ionic liquid. In some versions, the ionic liquid is used as a solvent to dissolve an ionic shuttle salt for transport of active material, with an optional co-solvent. Methods to synthesize the ionic liquid include contacting a boron cluster salt with a quaternary salt to form the ionic liquid by a metathesis reaction.

First claim

What is claimed is:

1. A lithium electrochemical cell, comprising:
an anode that contains a reduced form of an active material when at least partially charged;
a cathode; and
an electrolyte mediating ionic communication between the anode and the cathode, the electrolyte comprising:
a lithium salt; and
an ionic liquid having a formula:
A p Q,

wherein A is a quaternary cation comprising at least one of:
an ammonium cation having a structure:

 and
a phosphonium cation having a structure:

wherein R 1 , R 2 , R 3 , and R 4 is each, independently, selected from a group consisting of:
C2-C12 alkyl; and
poly(ethylene glycol) methyl ether having from 1-20 ethylene glycol subunits, and

wherein Q is a boron cluster anion and p is one or two.

2. The lithium electrochemical cell as recited in claim 1 , wherein the boron cluster anion has a formula [B y H (y-z-i) R z X i ] 2− , [CB( y-1 )H (y-z-i) R z X i ] − , [C 2 B (y-2) H (y-t-j-1) R t X j ] − , [C 2 B (y-3) H (y-t-j) R t X j ] − , or [C 2 B (y-3) H (y-t-j-1) R t X j ] 2− , and wherein:
y is an integer within a range of 6 to 12;
(z+i) is an integer within a range of 0 to y;
(t+j) is an integer within a range of 0 to (y−1);
X is F, Cl, Br, I, or a combination thereof; and
R is a substituent comprising any of:
group (i): a linear, branched-chain, or cyclic C1-C18 alkyl, perfluoroalkyl, or partially fluorinated alkyl group;
group (ii): a C6-C14 aryl, perfluoroaryl, or partially fluorinated aryl group;
group (iii): a linear, branched-chain, or cyclic C1-C18 alkoxy, perfluoroalkoxy, or partially fluorinated alkoxy group;
group (iv): a C6-C14 aryloxy, perfluoroaryloxy, or partially fluorinated aryloxy group; and
group (v): a substituent that combines moieties defined by two or more of groups (i)-(iv).

3. The lithium electrochemical cell as recited in claim 2 , wherein the electrolyte comprises a shuttle salt to improve transport of the active material between the anode and the cathode, the shuttle salt having an oxidized form of the active material as a cation.

4. The lithium electrochemical cell as recited in claim 2 , wherein the boron cluster anion comprises an icosahedral, closo-boron cluster anion.

5. The lithium electrochemical cell as recited in claim 2 , wherein the boron cluster anion comprises at least one of closo-[B 12 H 12 ] 2− , closo-[CB 11 H 12 ] − , and closo-[C 2 B 10 H 11 ] − .

6. A sodium electrochemical cell, comprising:
an anode that contains a reduced form of an active material when at least partially charged;
a cathode; and
an electrolyte mediating ionic communication between the anode and the cathode, the electrolyte comprising:
a sodium salt; and
an ionic liquid having a formula:
A p Q,

wherein A is a quaternary cation comprising at least one of:
an ammonium cation having a structure:

 and
a phosphonium cation having a structure:

wherein R 1 , R 2 , R 3 , and R 4 is each, independently, selected from a group consisting of:
C2-C12 alkyl; and
poly(ethylene glycol) methyl ether having from 1-20 ethylene glycol subunits, and

wherein Q is a boron cluster anion and p is one or two.

7. The sodium electrochemical cell as recited in claim 6 , wherein the boron cluster anion has a formula [B y H (y-z-i) R z X i ] 2− , [CB( y-1 )H (y-z-i) R z X i ] − , [C 2 B (y-2) H (y-t-j-1) R t X j ] − , [C 2 B (y-3) H (y-t-j) R t X j ] − , or [C 2 B (y-3) H (y-t-j-1) R t X j ] 2− , and wherein:
y is an integer within a range of 6 to 12;
(z+i) is an integer within a range of 0 to y;
(t+j) is an integer within a range of 0 to (y−1);
X is F, Cl, Br, I, or a combination thereof; and
R is a substituent comprising any of:
group (i): a linear, branched-chain, or cyclic C1-C18 alkyl, perfluoroalkyl, or partially fluorinated alkyl group;
group (ii): a C6-C14 aryl, perfluoroaryl, or partially fluorinated aryl group;
group (iii): a linear, branched-chain, or cyclic C1-C18 alkoxy, perfluoroalkoxy, or partially fluorinated alkoxy group;
group (iv): a C6-C14 aryloxy, perfluoroaryloxy, or partially fluorinated aryloxy group; and
group (v): a substituent that combines moieties defined by two or more of groups (i)-(iv).

8. The sodium electrochemical cell as recited in claim 6 , wherein the electrolyte comprises a shuttle salt to improve transport of the active material between the anode and the cathode, the shuttle salt having an oxidized form of the active material as a cation.

Assignees

• Toyota Eng & Mfg North America
• Univ Monash

Inventors

• Mohtadi Rana
• Tutusaus Oscar
• Macfarlane Douglas R
• Kar Mega

Classifications

• H01M10/0568

  characterised by the solutes · CPC title

• H01M10/056 Primary

  characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes · CPC title

• C07F5/02

  Boron compounds · CPC title

• H01M10/0525

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

• H01M2300/0045

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