Graphene hybrid materials, apparatuses, systems and methods

Patent metadata

Field	Value
Publication number	US-9236197-B2
Application number	US-201213401655-A
Country	US
Kind code	B2
Filing date	Feb 21, 2012
Priority date	Feb 18, 2011
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

Graphene based materials are provided in connection with various devices and methods of manufacturing. As consistent with one or more embodiments, an apparatus includes a graphene sheet and a single-crystal structure grown on the graphene sheet, with the graphene sheet and single-crystalline structure functioning as an electrode terminal. In various embodiments, the single-crystalline structure is grown on a graphene sheet, such as by using precursor particles to form nanoparticles at the distributed locations, and diffusing and recrystallizing the nanoparticles to form the single-crystal structure.

First claim

What is claimed is:

1. A method of manufacturing an electrode, the method comprising:
using precursor particles to form Ni(OH) 2 , Mn 3 O 4 or iron family element nanoparticles at respective locations on a low oxide graphene sheet; and
diffusing and recrystallizing the nanoparticles to form a single-crystal structure on a surface of the graphene sheet.

2. The method of claim 1 , wherein diffusing and recrystallizing the nanoparticles includes diffusing the nanoparticles across a graphitic lattice of the graphene sheet and recrystallizing the nanoparticles into single-crystalline structures.

3. The method of claim 1 , wherein the precursor particles are composed of a material used to form the nanoparticles, and using precursor particles to form nanoparticles at respective locations on a graphene sheet includes pre-coating precursor particles on a graphene sheet having an oxygen content that is less than 10%.

4. The method of claim 1 , wherein the precursor particles are composed of a material used to form the nanoparticles, and using precursor particles to form nanoparticles at respective locations on a graphene sheet includes pre-coating precursor particles on a graphene sheet having an oxygen content that is less than 5%.

5. The method of claim 1 , further including controlling the oxidation of the graphene sheet to maintain the oxygen content to a value that is less than 10%.

6. The method of claim 1 , further including uniformly pre-coating the precursor particles on a rolled graphene sheet.

7. The method of claim 1 , further including uniformly pre-coating the precursor particles on a planar graphene sheet.

8. The method of claim 1 , wherein diffusing and recrystallizing the nanoparticles includes diffusing the nanoparticles across a graphitic lattice of the graphene sheet and recrystallizing the nanoparticles into a plurality of single-crystalline nanoplates, further including stacking the plurality of single-crystalline nanoplates to form an electrochemical pseudo-capacitor electrode.

9. The method of claim 1 , wherein diffusing and recrystallizing the nanoparticles includes hydrothermally treating the nanoparticles and forming at least one type of nanocrystals selected from the group consisting of hydroxide, oxide, sulfide and selenide nanocrystals, respectively of at least one of the group consisting of Mn 3 O 4 nanoparticles and iron family elements selected from the group consisting of Ni, Co, Mn, Mo, Ru and Fe.

10. The method of claim 1 , further including forming the graphene sheet to a degree of oxidation and controlling the reaction temperature of the recrystallizing of the nanoparticles, to control the morphology of the single-crystal structure to set capacitance and discharge current density values of the electrode.

11. The method of claim 1 , wherein diffusing and recrystallizing the nanoparticles to form a single-crystal structure includes forming Ni(OH) 2 nanoplates attached to the graphene sheet at (001) crystallographic planes.

12. The method of claim 1 , including providing the single-crystal structure as grown on the graphene sheet, with the graphene sheet and single-crystalline structure being configured and arranged as one electrode terminal.

13. The method of claim 12 , wherein the single-crystal structure and graphene sheet are coupled to an electrode, and the single-crystal structure is configured and arranged to facilitate exchange of charge carriers with the electrode.

14. The method of claim 12 , wherein the single-crystal structure includes at least one of Mn 3 O 4 and iron family elements selected from the group consisting of Ni, Co, Mn, Mo, Ru and Fe.

15. The method of claim 12 , further including a plurality of the graphene sheets with a single-crystal structure grown thereupon and stacked in layers that form an electrochemical pseudo-capacitor electrode.

16. The method of claim 12 , wherein the single-crystal structure includes an Ni(OH) 2 nanoplate attached to the graphene sheet at (001) crystallographic planes.

17. The method of claim 12 , further including providing:
another electrode terminal, whereby said one electrode terminal and the other electrode terminal are first and second electrodes respectively; and
a separator between the first and second electrodes and configured and arranged to facilitate ion exchange between the first and second electrodes.

18. The method of claim 17 , wherein the single-crystal structure is a pseudocapacitive material configured and arranged with the graphene sheet to exhibit specific capacitance and energy density that is higher than a specific capacitance and energy capacity of the graphene sheet.

19. The method of claim 17 , wherein the single-crystal structure includes Ni(OH) 2 .

20. The method of claim 17 , wherein the first electrode includes a plurality of the graphene sheets with a single-crystal structure grown upon each sheet, the plurality of graphene sheets overlapping one another to form a three-dimensional conducting network that is configured and arranged to transfer electrons between the graphene sheet and the separator.

21. The method of claim 17 , wherein the second electrode includes a RuO 2 graphene hybrid material including RuO 2 grown on a graphene sheet.

22. The method of claim 17 , wherein
the single-crystal structure includes Ni(OH) 2 , and
the second electrode includes a RuO 2 graphene hybrid material including RuO 2 grown on a graphene sheet.

23. The method of claim 17 , wherein the first electrode is an anode and includes single-crystal Mn 3 O 4 configured and arranged to interact with lithium ions for passing charge carriers between the first and second electrodes.

24. The method of claim 17 , wherein the first electrode is a cathode and includes LiMn 1-x Fe x PO 4 nanorods configured and arranged to facilitate diffusion of lithium charge carriers between the first and second electrodes.

25. The method of claim 1 , wherein in one stage of manufacturing, the graphene sheet is in a first form, and then rolled.

Assignees

• Dai Hongjie
• Wang Hailiang
• Univ Leland Stanford Junior

Inventors

• Dai Hongjie
• Wang Hailiang

Classifications

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01M4/366

  as layered products · CPC title

• Y02P70/54

  Cross-Sectional Technologies · mapped topic