Graphene frameworks for supercapacitors

Patent metadata

Field	Value
Publication number	US-2017213656-A1
Application number	US-201715415732-A
Country	US
Kind code	A1
Filing date	Jan 25, 2017
Priority date	Jan 26, 2016
Publication date	Jul 27, 2017
Grant date	—

Abstract

The present disclosure provides supercapacitors that may avoid shortcomings of current energy storage technology. Provided herein are materials and fabrication processes of such supercapacitors. In some embodiments, an electrochemical system comprising a first electrode, a second electrode, wherein at least one of the first electrode and the second electrode comprises a three dimensional porous reduced graphene oxide framework.

First claim

What is claimed is:

1 . An electrode comprising a 3D graphene framework, comprising:
a) an interconnected conductive network of graphene sheets with a porous structure; and b) a composite material comprising a capacitive or pseudo-capacitive material.

2 . The electrode of claim 1 , further comprising a current collector.

3 . The electrode of claim 1 , wherein the 3D graphene framework comprises a holey 3D graphene framework.

4 . The electrode of claim 3 , provided that the electrode has a specific surface area of about 450 m 2 /g to about 3,000 m 2 /g.

5 . The electrode of claim 3 , provided that the electrode has a loading ratio of about 30% to about 99%.

6 . The electrode of claim 3 , provided that the electrode has a cycle lifetime of about 500 cycles to about 2,000,000 cycles.

7 . The electrode of claim 3 , provided that the electrode has a specific capacity at a C-rate of about

0 . 1 of about 250 mAh/g to about 4,000 mAh/g.

8 . The electrode of claim 1 , provided that the electrode has a porosity of about 90% to about 99%.

9 . The electrode of claim 1 , provided that the electrode has a pore diameter of about 0.002 μm to about 100,000 μm.

10 . The electrode of claim 1 , wherein the composite material comprises silicon, sulfur, Nb 2 O 5 , Al 2 O 3 , V 2 O 5 , Re 2 O 7 , CrO 3 , CeO 2 , RuO 2 , ZrO 2 , MoO 3 , WO 3 , TiO 2 , or any combination thereof.

11 . An energy storage device comprising:
a) a first electrode and a second electrode; and b) an electrolyte;
wherein at least one of the first electrode and the second electrode comprises a 3D graphene framework, wherein the 3D graphene framework comprises an interconnected conductive network of graphene sheets with a porous structure
wherein at least one of the first electrode and the second electrode further comprise a composite material comprising a capacitive or pseudo-capacitive material.

12 . The energy storage device of claim 11 , wherein the 3D graphene framework comprises a holey 3D graphene framework.

13 . The energy storage device of claim 11 , wherein the electrolyte is a non-aqueous electrolyte comprising lithium hexafluorophosphate, iodomethane, dimethyl sulfate, dimethyl carbonate, tetramethylammonium chloride, methyl triflate, diazomethane, methyl fluorosulfonate ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide, nitromethane, propylene carbonate, ethylene carbonate, lithium bis(trifluoromethanesulphonyl)imide, 1-2 dimethoxyethane, 1,3-dioxolane, lithium nitrate, or any combination thereof.

14 . The energy storage device of claim 11 , provided that the energy storage device has a stack-specific energy density of about 16 Wh/kg to about 750 Wh/kg.

15 . The energy storage device of claim 11 , provided that the energy storage device has a stack-specific power density of about 0.5 kW/kg to about 20 kW/kg.

16 . The energy storage device of claim 11 , provided that the energy storage device has an electrode-specific gravimetric energy density of about 16 Wh/kg to about 900 Wh/kg.

17 . The energy storage device of claim 11 , provided that the energy storage device has an electrode-specific gravimetric power density of about 0.5 kW/kg to about 40 kW/kg.

18 . The energy storage device of claim 11 , provided that the energy storage device has a total capacitance of about 1 mF to about 10 F.

19 . A method of composing an electrode comprising:
a) forming a solution of graphene oxide and a first solvent; b) heating the solution to form a holey graphene oxide; c) centrifuging the holey graphene oxide in the solution; d) washing the holey graphene oxide in a second solvent; e) forming a dispersion of the holey graphene oxide in a third solvent; and f) adding an acid to the dispersion to form a holey graphene oxide framework.

20 . The method of composing an electrode of claim 19 , wherein the method is capable of continuously forming an electrode in a roll-to-roll process.

21 . The method of composing an electrode of claim 19 , wherein the concentration of graphene oxide in the solution is about 1.15 g/L to about 4.6 g/L.

22 . The method of composing an electrode of claim 19 , wherein the first solvent comprises an oxidizing agent comprising oxygen, ozone, hydrogen peroxide, fluorite dioxide, lithium peroxide, barium peroxide, fluorine, chlorine, nitric acid, nitrate compounds, sulfuric acid, peroxydisulfuric acid, peroxymonosulfuric acid, chlorite, chlorate, perchlorate, halogen compounds hypochlorite, hypohalite compounds, household bleach, hexavalent chromium compounds, chromic acids, dichromic acids, chromium trioxide, pyridinium chlorochromate, chromate compounds, dichromate compounds, permanganate compounds, potassium permanganate, sodium perborate, nitrous oxide, potassium nitrate, sodium bismuthate or any combination thereof.

23 . The method of composing an electrode of claim 19 , wherein the solution is heated to a temperature of about 50° C. to about 200° C.

24 . The method of composing an electrode of claim 19 , wherein at least one of the second solvent and the third solvent comprises formic acid, n-Butanol, isopropanol, n-propanol, ethanol, methanol, acetic acid, water or any combination thereof.

25 . The method of composing an electrode of claim 19 , wherein the acid comprises a weak acid, comprising formic acetic, acetic acid, trichloroacetic acid, hydrofluoric acid, hydrocyanic, hydrogen sulfide or any combination thereof.

26 . The method of composing an electrode of claim 19 , further comprising pressing the holey graphene oxide framework onto a metallic foam comprising steel, stainless nickel, aluminum, copper, bismuth, chromium, cobalt, gallium, gold, iron, indium, lead, magnesium, mercury, silver, sodium, tin, titanium, zinc, zirconium, bronze or any combination thereof.

27 . The method of composing an electrode of claim 19 , further comprising depositing the holey graphene oxide framework onto a current collector comprising:
a) a metal film comprising silver, copper, gold, aluminum, calcium, tungsten, zinc, tungsten, brass, bronze, nickel, lithium, iron, platinum, tin, carbon steel, lead, titanium, stainless steel, mercury, chromium, gallium arsenide, or any combination thereof; or b) a polymeric film comprising polyfluorene, polyphenylene, polypyrene, polyazulene, polynaphthalene, polyacetylene, poly p-phenylene vinylene, polypyrrole, polycarbazole, polyindole, polyazepinem, polyaniline, polythiophene, poly 3,4-ethylenedioxythiophene, poly p-phenylene sulfide, polyacetylene, poly p-phenylene vinylene, or any combination thereof.

28 . A method of composing an electrode with a three-dimensional graphene framework with an ultra-high sulfur content, the method comprising:
a) synthesizing graphene oxide comprising:
i. forming a graphene oxide suspension; and
ii. drying the suspension; and
b) synthesizing a composite sulfur-graphene oxide from the graphene oxide comprising:
i. adding a sulfur precursor to the graphene oxide suspension and a first solvent;
ii. adding a first acid to form a first solution;
iii. stirring the first solution;
iv. adding a second acid to the first solution to form a second solution;
v. heating the second solution;
vi. washing the second solution in a second solvent; and
vii. freeze drying the second solution.

Assignees

• Univ California

Inventors

• Duan Xiangfeng
• Huang Yu
• Papandrea Benjamin
• Xu Xu

Classifications

• H01G11/32 Primary

  Carbon-based · CPC title

• H01G11/66

  Current collectors · CPC title

• H01G11/36

  Nanostructures, e.g. nanofibres, nanotubes or fullerenes · CPC title

• H01G11/86

  specially adapted for electrodes (carbonisation or activation of carbon for the manufacture of electrodes H01G11/34) · CPC title

• H01G11/58

  Liquid electrolytes · CPC title