Electrolyte formulations for electrochemical cells containing a silicon electrode

Patent metadata

Field	Value
Publication number	US-10797349-B2
Application number	US-201816186619-A
Country	US
Kind code	B2
Filing date	Nov 12, 2018
Priority date	Aug 30, 2016
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

Additives to electrolytes that enable the formation of comparatively more robust SEI films on silicon anodes. The SEI films in these embodiments are seen to be more robust in part because the batteries containing these materials have higher coulombic efficiency and longer cycle life than comparable batteries without such additives. The additives preferably contain a nitrate group.

First claim

The invention claimed is:

1. An electrochemical cell comprising:
a silicongraphite composite anode that comprises greater than 50 weight percent graphite;
a cathode comprising a lithium ion intercalating material, wherein discharge and recharge of the electrochemical cell is accomplished by intercalation and de-intercalation of lithium ions into and from the cathode; and
a liquid electrolyte solution comprising an additive, wherein the additive is represented by the chemical structural formula:

where X comprises a metal group selected from the group consisting of alkaline earth metals and post transition metals.

2. The electrochemical cell of claim 1 , wherein the lithium ion intercalating material is represented by the chemical structural formula:
LiNi x Mn y Co z O 2   (ii)

where x+y+z=1.

3. The electrochemical cell of claim 1 , wherein the lithium ion intercalating material is represented by the chemical structural formula LiNi 0.33 Mn 0.33 Co 0.33 O 2 .

4. The electrochemical cell of claim 1 , wherein X comprises an alkaline earth metal.

5. The electrochemical cell of claim 4 , wherein X comprises magnesium.

6. The electrochemical cell of claim 5 , wherein the additive comprises magnesium nitrate.

7. The electrochemical cell of claim 1 , wherein X comprises a post transition metal.

8. The electrochemical cell of claim 7 , wherein X comprises aluminum.

9. The electrochemical cell of claim 8 , wherein the additive comprises aluminum nitrate.

10. The electrochemical cell of claim 1 , wherein a concentration of the additive is no greater than 6 weight percent of a total weight of the liquid electrolyte solution.

11. The electrochemical cell of claim 1 , wherein the liquid electrolyte solution further comprises an organic solvent that comprises ethylene carbonate.

12. An electrochemical cell comprising:
a silicongraphite composite anode that comprises greater than 50 weight percent graphite of a total weight of the silicon-graphite composite anode;
a cathode comprising a lithium ion intercalating material, wherein discharge and recharge of the electrochemical cell is accomplished by intercalation and de-intercalation of lithium ions into and from the cathode; and
a liquid electrolyte solution comprising a lithium salt, an organic solvent, and an additive, wherein the additive is one of magnesium nitrate or aluminum nitrate.

13. The electrochemical cell of claim 12 , wherein the organic solvent comprises ethylene carbonate.

14. The electrochemical cell of claim 12 , wherein a concentration of the additive is no greater than 6 weight percent of a total weight of the liquid electrolyte solution.

Assignees

• Wildcat discovery technologies inc

Inventors

• Zhu Ye
• Cheng Gang
• Strand Deidre
• Yang Jen-Hsien

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M10/0525

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

• Y02E60/10

  Energy storage using batteries · CPC title