Method for preparing hard carbon anode of lithium/sodium ion battery by biochar

Patent metadata

Field	Value
Publication number	US-12172898-B2
Application number	US-202117595274-A
Country	US
Kind code	B2
Filing date	Oct 12, 2021
Priority date	Sep 29, 2021
Publication date	Dec 24, 2024
Grant date	Dec 24, 2024

Abstract

Provided is a method for preparing a hard carbon anode of a lithium/sodium ion battery by biochar, which includes the following steps: S1 biochar pretreatment, S2, preparing a precursor material and S3 pyrolysis carbonization, by a modification of the biochar, setting carbonization temperature and carbonization time, and controlling a cooling rate, so that the obtained biochar generates amorphous carbon after carbonization with low graphitization degree, few surface defects, larger charge-discharge specific capacity, and stable performance in the cycle charging and discharging process; at the same time, the process of the application is relatively simple, and a special complex process is reduced; the present method is suitable for a large-scale industrial production without special adjustment or control of a morphology; and the product performance is relatively good and thus has certain competitive advantages.

First claim

The invention claimed is:

1. A method for preparing a hard carbon anode of a lithium/sodium ion battery with a biochar, wherein it comprises:
S1, biochar pretreatment: adding a hydrochloric acid to a modified biochar for a pickling for 3 to 12 hours, and then rinsing with a deionized water to neutrality;
S2, precursor material preparation: pouring the rinsed biochar into a ball mill jar, adding an absolute ethanol for a milling and crushing, filtering and drying after the ball milling is completed to obtain the precursor material; and
S3, pyrolysis carbonization: placing the precursor material obtained above in a tubular furnace, carbonizing in an argon atmosphere with a carbonization temperature of 1200 to 1300° C., a carbonization time of 0.5 to 3 hours, and an aeration rate of 10 to 30 mL/min; performing a heat preservation for 1 to 3 hours after the carbonization is finished, cooling to 800 to 1100° C., and then inletting the argon for a natural cooling to 25 to 30° C. to obtain a hard carbon anode material.

2. The method according to of claim 1 , wherein the modified biochar is prepared by impregnating the biochar in a modified liquid at 20 to 40° C. for 0.2 to 2.5 hours, and then drying at 150 to 200° C.

3. The method according to claim 2 , wherein the modified liquid is N-N dimethylformamide and m-aminophenylurea hydrochloride solution in a volume ratio of 1 to 5:3.

4. The method according to claim 1 , wherein a concentration of the hydrochloric acid in S1 is 0.5 to 1.5 M.

5. The method according to claim 1 , wherein a mass-volume ratio of the biochar and the hydrochloric acid in Si is 1:0.077 to 0.13 g/mL.

6. The method according to claim 1 , wherein a mass-volume ratio of the biochar and the absolute ethanol in S2 is 0.6 to 1.3:3 to 5 g/mL.

7. The method according to claim 1 , wherein a revolving speed of the ball mill jar in S2 is 200 to 500 rpm, and a ball milling time is 3 to 12 hours.

8. The method according to claim 1 , wherein a temperature elevation program of the tubular furnace in S3 is 30° C. to 1000° C.: a temperature elevation rate is 4 to 6° C./min, and 1000 to 1300° C.: the temperature elevation rate is 3 to 5° C./min.

9. The method according to claim 1 , wherein a cooling rate of the tubular furnace in S3 is 3 to 5° C./min.

Assignees

• Univ Hainan

Inventors

• Chen Yong
• Zheng Heng
• Mo Yan
• Cao Bokai

Classifications

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M10/36

  Accumulators not provided for in groups H01M10/05-H01M10/34 · CPC title

• H01M10/0525

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

• C01P2006/40

  Electric properties · CPC title

• C01P2002/82

  by IR- or Raman-data · CPC title