Electrolyte and electrochemical device

Patent metadata

Field	Value
Publication number	US-11145901-B2
Application number	US-201916406943-A
Country	US
Kind code	B2
Filing date	May 8, 2019
Priority date	Nov 20, 2018
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

The present application relates to an electrolyte and an electrochemical device. The electrolyte includes an organic solvent, an additive and a lithium salt, the additive including a cyclic borate and a nitrile compound. The electrolyte of the present application has good stability at a high working voltage. In another embodiment of the present application, the combination of the electrolyte and an anode having a high compacted density provides a high energy density for the electrochemical device, and improves the storage, floating charge and dynamicperformance of the electrochemical device.

First claim

What is claimed is:

1. An electrolyte, comprising an organic solvent, an additive and a lithium salt, the additive comprising a cyclic borate and a nitrile compound, wherein the cyclic borate has the following structure:

wherein the organic solvent comprises a carboxylate having the following structure:

wherein R 4 and R 5 are each independently an alkyl group having 1-5 carbon atoms, and
wherein the carboxylate has a content of 10%-30%,
wherein the additive further comprises a fluorosulfonate, based on a total weight of the electrolyte, a content of the fluorosulfonate being about 0.01% to about 5%.

2. The electrolyte of claim 1 , wherein based on the total weight of the electrolyte, a content of the nitrile compound is about 0.05% to about 6%, and a content of the cyclic borate is about 0.01% to about 3%.

3. The electrolyte of claim 1 , wherein the nitrile compound has the following structure:

wherein:
A is selected from a chain alkyl group having 1-6 carbon atoms, a cycloalkyl group having 3-12 carbon atoms, an alkylene group having 2-6 carbon atoms or a cyclic alkylene group having 6-12 carbon atoms;
R 2 and R 3 are each independently selected from a hydrogen atom, a cyano group, a nitrile group having 1-5 carbon atoms or an alkyl group having 1-8 carbon atoms;
X 1 , X 2 and X 3 are each independently selected from —CH 2 —, —O—, —OCH 2 —, —OCH 2 CH 2 CH 2 —, —OCH 2 CH 2 —, —CHF— or —CF 2 —; and
n 1 , n 2 and n 3 are each independently an integer selected from 0-10.

4. The electrolyte of claim 1 , wherein the nitrile compound is at least one selected from the group consisting of:

5. The electrolyte of claim 1 , wherein the fluorosulfonate has the following structure:

wherein:
R 6 and R 7 are each independently selected from an alkyl group having 2-20 carbon atoms, a fluoroalkyl group having 2-20 carbon atoms, an alkoxy group having 2-10 carbon atoms, a fluoroalkoxy group having 2-10 carbon atoms, an alkenyl group having 2-20 carbon atoms or a fluoroalkenyl group having 2-20 carbon atoms.

6. The electrolyte of claim 1 , wherein the fluorosulfonate is at least one selected from the group consisting of:

7. The electrolyte of claim 1 , wherein the additive further comprising at least one other film-forming additive selected from the group consisting of fluoroethylene carbonate, vinylene carbonate, 1,3-propane sultone, 1,3,2-Dioxathiolane 2,2-dioxide, methylene methanedisulfonate and lithium bis(oxalate)borate.

8. An electrochemical device, comprising:
a cathode;
an anode;
a separator; and
an electrolyte,
wherein the anode has a compacted density of not less than about 1.75 g/cm 3 , and
wherein the electrolyte comprises an organic solvent, an additive and a lithium salt, the additive comprising a cyclic borate and a nitrile compound, wherein the cyclic borate has the following structure:

wherein the organic solvent comprises a carboxylate having the following structure:

wherein R 4 and R 5 are each independently an alkyl group having 1-5 carbon atoms, and
wherein the carboxylate has a content of 10%-30%,
wherein the additive further comprises a fluorosulfonate, based on a total weight of the electrolyte, a content of the fluorosulfonate being about 0.01% to about 5%.

9. The electrochemical device of claim 8 , wherein the nitrile compound has the following structure:

wherein:
A is selected from a chain alkyl group having 1-6 carbon atoms, a cycloalkyl group having 3-12 carbon atoms, an alkylene group having 2-6 carbon atoms or a cyclic alkylene group having 6-12 carbon atoms;
R 2 and R 3 are each independently selected from a hydrogen atom, a cyano group, a nitrile group having 1-5 carbon atoms or an alkyl group having 1-8 carbon atoms;
X 1 , X 2 and X 3 are each independently selected from —CH 2 —, —O—, —OCH 2 —, —OCH 2 CH 2 CH 2 —, —OCH 2 CH 2 —, —CHF— or —CF 2 —; and
n 1 , n 2 and n 3 are each independently an integer selected from 0-10.

10. The electrochemical device of claim 8 , wherein the nitrile compound is at least one selected from the group consisting of:

11. The electrochemical device of claim 8 , wherein the fluorosulfonate has the following structure:

wherein:
R 6 and R 7 are each independently selected from an alkyl group having 2-20 carbon atoms, a fluoroalkyl group having 2-20 carbon atoms, an alkoxy group having 2-10 carbon atoms, a fluoroalkoxy group having 2-10 carbon atoms, an alkenyl group having 2-20 carbon atoms or a fluoroalkenyl group having 2-20 carbon atoms.

12. The electrochemical device of claim 11 , wherein the fluorosulfonate is at least one selected from the group consisting of:

13. The electrochemical device of claim 8 , wherein the additive further comprising at least one other film-forming additive selected from the group consisting of fluoroethylene carbonate, vinylene carbonate, 1,3-propane sultone, 1,3,2-Dioxathiolane 2,2-dioxide, methylene methanedisulfonate and lithium bis(oxalate)borate.

14. An electronic device, comprising the electrochemical device of claim 8 .

Assignees

• Ningde Amperex Technology Ltd

Inventors

• Ma Juan
• Zhang Shuirong
• Liu Junfei
• Tang Chao

Classifications

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M10/0525

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

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title

• H01M10/0569

  characterised by the solvents · CPC title

• H01M10/0568

  characterised by the solutes · CPC title