Carbogel anode materials and method for their preperation

Patent metadata

Field	Value
Publication number	US-11117802-B2
Application number	US-201716083562-A
Country	US
Kind code	B2
Filing date	Feb 3, 2017
Priority date	Mar 9, 2016
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

Carbogel anode materials and method for their preparation are disclosed. The described carbogels exhibit, at a temperature of 20° C., an electrical conductance of at least 0.5 S/cm and a reversible electrochemical capacity in relation to lithium of at least 350 mAh/g under a C/2 discharge current, enabling their use for preparation of anode materials, particularly those intended for preparation of lithium-ion cells.

First claim

The invention claimed is:

1. A carbogel comprising at least 92% by wt. of carbon and exhibiting, at a temperature of 20° C., an electrical conductance of at least 0.5 S/cm and a reversible electrochemical capacity in relation to lithium of at least 350 mAh/g under a C/2 discharge current;
wherein the carbogel is prepared by a method comprising the steps of:
subjecting an aqueous suspension comprising 1-30% by wt. of a first starch composition consisting of rice starch in the amount of 75-99% by wt. and a second starch type in the amount of 1-25% by wt. to polycondensation at a temperature of 50-90° C.;
carrying out a solvent exchange using an aqueous solutions of an alcohol or a ketone with a concentration increasing from 10% to 99.8% to obtain an organic alcogel, and

subjecting the obtained organic alcogel to a pyrolysis process at a temperature of 300-2000° C. immediately following the solvent exchange step.

2. The carbogel according to claim 1 , wherein it exhibits a low roughness, vitreousness, lack of mesopores, and an ordered hierarchical lamellar structure.

3. A method for preparation of the carbogel according to claim 1 , wherein the method comprises the steps of:
subjecting an aqueous suspension comprising 1-30% by wt. of a starch composition consisting of rice starch in the amount of 75-99% by wt. and another starch type in the amount of 1-25% by wt. to polycondensation at a temperature of 50-90° C.;
carrying out a solvent exchange using an aqueous solutions of an alcohol or a ketone with a concentration increasing from 10% to 99.8%; and

subjecting the obtained organic alcogel to a pyrolysis process at a temperature of 300-2000° C. immediately following the solvent exchange step.

4. The carbogel according to claim 1 , wherein it has a structure obtained by the method defined in claim 3 .

5. The method according to claim 3 , wherein as the second starch type, starch selected from the group comprising: corn starch, potato starch, wheat starch, tapioca starch, and sago starch, is used.

6. The carbogel according to claim 1 , wherein it has a structure obtained by the method defined in claim 5 .

7. The method according to claim 3 , wherein as the alcohol, one selected from the group comprising: ethanol, methanol, and isopropanol, is used.

8. The carbogel according to claim 1 , wherein it has a structure obtained by the method defined in claim 7 .

9. The method according to claim 3 , wherein acetone is used as the ketone.

10. The carbogel according to claim 1 , wherein it has a structure obtained by the method defined in claim 9 .

11. The method according to claim 3 , wherein the pyrolysis is carried out under inert conditions.

12. The carbogel according to claim 1 , wherein it has a structure obtained by the method defined in claim 11 .

13. The method according to claim 11 , wherein the pyrolysis is carried out in an inert gas atmosphere, preferably selected from a group including: argon, nitrogen, and helium.

14. The carbogel according to claim 1 , wherein it has a structure obtained by the method defined in claim 13 .

15. The method according to claim 3 , wherein the pyrolysis is carried out under slightly reducing conditions.

16. The method according to claim 3 , wherein the pyrolysis is carried out in vacuo.

17. An anode material made from a carbogel for use in a lithium-ion cell, the carbogel comprising:
at least 92% by wt. of carbon; and
exhibiting, at a temperature of 20° C., an electrical conductance of at least 0.5 S/cm and a reversible electrochemical capacity in relation to lithium of at least 350 mAh/g under a C/2 discharge current; and wherein
the carbogel is prepared by a method comprising the steps of:
subjecting an aqueous suspension comprising 1-30% by wt. of a first starch composition consisting of rice starch in the amount of 75-99% by wt. and a second starch type in the amount of 1-25% by wt. to polycondensation at a temperature of 50-90° C.;
carrying out a solvent exchange using an aqueous solutions of an alcohol or a ketone with a concentration increasing from 10% to 99.8% to obtain an organic alcogel, and

subjecting the obtained organic alcogel to a pyrolysis process at a temperature of 300-2000° C. immediately following the solvent exchange step.

18. The anode material of claim 17 , wherein the carbogel exhibits a low roughness, vitreousness, lack of mesopores, and an ordered hierarchical lamellar structure.

Assignees

• Univ Jagiellonski

Inventors

• Bakierska Monika
• Molenda Marcin
• Chojnacka Agnieszka
• Swietoslawski Michal

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• H01M10/0525

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

• H01M4/587

  for inserting or intercalating light metals · CPC title

• C01B32/05 Primary

  Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30 · CPC title

• C01B32/00

  Carbon; Compounds thereof (C01B21/00, C01B23/00 take precedence; percarbonates C01B15/10; carbon black C09C1/48) · CPC title