Porous carbon product, method for the production thereof, and use of the same

• US 9,287,556 B2
• Filed: 10/19/2011
• Issued: 03/15/2016
• Est. Priority Date: 10/25/2010
• Status: Active Grant

• Current Assignee: Heraeus Quarzglas GmbH & Co. KG (Heraeus Holding GMBH)
• Original Assignee: Heraeus Quarzglas GmbH & Co. KG (Heraeus Holding GMBH)
• Inventors: Neumann, Christian, Becker, Joerg
• Primary Examiner(s): Ridley, Basia
• Assistant Examiner(s): Erwin, James
• Application Number:
  US13/881,675
• Publication Number:
  US 20130209891A1
• Time in Patent Office: 1,609 Days
• Field of Search: 429/231.8, 264/29.1, 252/502, 423/414
• US Class Current: 1/1
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/28042 Shaped bodies; Monolithic structures
• CPC Class Codes: B01J 20/28057 Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28059 being less than 100 m2/g
• CPC Class Codes: B01J 20/28069 Pore volume, e.g. total pore volume, mesopore volume, micropore volume
• CPC Class Codes: B01J 20/3064 Addition of pore forming agents, e.g. pore inducing or porogenic agents
• CPC Class Codes: C01B 32/00 Carbon; Compounds thereof C01B21/00, C01B23/00 take precedence; percarbonates C01B15/10; carbon black C09C1/48
• CPC Class Codes: C01B 32/205 Preparation
• CPC Class Codes: C01B 32/372 Coating; Grafting; Microencapsulation
• CPC Class Codes: C04B 2111/00853 in electrochemical cells or batteries, e.g. fuel cells
• CPC Class Codes: C04B 35/521 obtained by impregnation of carbon products with a carbonisable material
• CPC Class Codes: C04B 38/0615 the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles C04B38/0022 takes precedence
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/0402 Methods of deposition of the material
• CPC Class Codes: H01M 4/0416 involving impregnation with a solution, dispersion, paste or dry powder H01M4/0438 takes precedence
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/1393 of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/587 : for inserting or intercalating light metals
• CPC Class Codes: H01M 4/96 : Carbon-based electrodes
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/50 : Fuel cells

Abstract

For use as electrode material for a lithium battery, porous templates are impregnated with a carbon feedstock that can be graphitized. This frequently results in only a low thickness of the deposited, graphite-like layer, such that generally several such infiltration and carbonation processes must be carried out consecutively. In order to provide a cost-effective product which is made of porous carbon and has high porosity and a low surface, according to the invention a method comprises the following method steps: (a) preparing a porous carbon structure having a large specific surface, (b) infiltrating the carbon structure with a precursor substance for carbon that can be graphitized, (c) carbonizing the precursor substance to form the carbon product having a low specific surface, wherein preparing the carbon structure according to method step (a) comprises the following: (I) preparing a template containing pores, (II) infiltrating the pores of the template with a solution that contains a precursor of carbon that cannot be graphitized, (III) carbonizing the precursor forming the carbon structure having the first specific surface, and (IV) removing the template.

Claims

1. A method for producing a porous carbon product, comprising:

providing a porous carbon structure with a first specific surface area,

infiltrating the carbon structure with a precursor substance for graphitizable carbon,

carbonizing the precursor substance so as to form the porous carbon product with a second specific surface area smaller than the first specific surface area,

wherein said providing the porous carbon structure comprises;

providing a template containing pores,

infiltrating the pores of the template with a solution containing a precursor for non-graphitizable carbon,

carbonizing the precursor so as to form the porous carbon structure having the first specific surface area, and

removing the template.

2. The method according to claim 1, wherein the precursor for non-graphitizable carbon is water-soluble carbohydrate.

3. The method according to claim 1, wherein during said carbonization of the precursor, a carbon structure is produced with a specific BET surface area in a range of 400-600 m²/g.

4. The method according to claim 3, wherein said carbonizing of the precursor substance takes place in an inert gas atmosphere at a temperature of at least 500°

C.

5. The method according to claim 4, wherein said carbonizing of the precursor substance is followed by an activation treatment in an oxidizing atmosphere at a temperature ranging from 200°

C. to 450°

C.

6. The method according to claim 1, wherein while the carbon precursor substance is carbonized the porous carbon product is produced with a specific BET surface area of less than 50 m²/g.

7. The method according to claim 1, wherein said providing the template comprises producing synthetic silica soot with a hierarchical pore structure.

8. The method according to claim 7, wherein said producing synthetic silica soot comprises a soot deposition process in which a SiO₂ start compound is converted by hydrolysis or pyrolysis into SiO₂ particles, wherein the SiO₂ particles are agglomerated or aggregated and deposited so as to form the template from the silica soot having an anisotropic mass distribution with the hierarchical pore structure.

9. The method according to claim 1, wherein the precursor substance is mesophase pitch.

10. The method according to claim 1, wherein the porous carbon product is produced in a form of finely divided porous carbon flakes.

18. The method according to claim 1, wherein the precursor for non-graphitizable carbon is saccharose.

19. The method according to claim 4, wherein carbonizing is followed by an activation treatment in an oxidizing atmosphere at a temperature in the range of 350°

C. to 425°

C.

11. A porous carbon product comprising a core-shell structure comprising a core of a first carbon variety and a shell surrounding the core and of a second carbon variety, wherein the first carbon variety is turbostratic carbon having a first microporosity and the second carbon variety is graphite-like carbon having a second microporosity smaller than the first microporosity.

12. The porous carbon product according to claim 11, wherein the porous carbon product has a hierarchical pore structure.

13. The porous carbon product according to claim 11, wherein the porous carbon product is in the form of porous carbon flakes comprising carbon layers having a mean layer thickness in a range from 10 μ

m to 200 μ

m.

14. A method comprising:

providing a porous carbon product according to claim 11; and

producing an electrode for a rechargeable lithium ion battery therewith.

15. The method according to claim 14, wherein the porous carbon product has a hierarchical pore structure.

16. The method according to claim 14, wherein the porous carbon product is in the form of porous carbon flakes comprising carbon layers having a mean layer thickness in a range from 10 μ

m to 200 μ

m.

17. The method according to claim 14, wherein the porous carbon product is in the form of porous carbon flakes comprising carbon layers having a mean layer thickness in a range from 30 μ

m to 100 μ

m.

20. The porous carbon product according to claim 11, wherein the porous carbon product is in the form of porous carbon flakes comprising carbon layers having a mean layer thickness in a range from 30 μ

m to 100 μ

m.