Material comprising reduced graphene oxide, a device comprising the material and a method of producing the material

Patent metadata

Field	Value
Publication number	US-9865380-B2
Application number	US-201314890391-A
Country	US
Kind code	B2
Filing date	Jun 24, 2013
Priority date	Jun 24, 2013
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

The present invention relates to a material comprising reduced graphene oxide, wherein the degree of reduction of the graphene oxide exhibits a spatial variation so that the material exhibits a gradient in the electric conductivity and/or permittivity. The material can for example be used in an electric device for purposes of field grading and/or dissipation of charges. Examples of electric devices wherein the material is beneficial includes cable accessories, bushings, power cables, microelectronics, switchgear, etc. The invention further relates to a method of producing a material for electrical applications. The method comprises treating different parts of a graphene oxide element differently, so as to achieve a different degree of reduction of the graphene oxide within the element, resulting in a sample having a gradient in the electrical conductivity and/or permittivity. The material could for example be obtained by means of applying a thermal gradient to a graphene oxide element, or by irradiation of a graphene oxide element.

First claim

The invention claimed is:

1. A material comprising reduced graphene oxide, wherein the degree of reduction of the graphene oxide exhibits a spatial variation so that the material exhibits a gradient in the electric conductivity and/or permittivity, and wherein the degree of reduction continuously increases from a low conductivity/permittivity surface of the material to a high conductivity/permittivity surface of the material;
wherein the ratio of the electrical conductivity of the high conductivity/permittivity surface of the material to the electrical conductivity of the low conductivity/permittivity surface of the material exceeds 10 2 ; and
wherein the material has a thickness of 0.1-10 mm.

2. The material of claim 1 , wherein the material comprises a composite of a polymer matrix and filler particles comprising reduced graphene oxide, where the degree of reduction of the filler particles exhibit a spatial variation.

3. The material of claim 1 , wherein the material comprises graphene oxide paper which has been reduced in a manner so that the degree of reduction exhibits a spatial variation.

4. The material of claim 3 , wherein at least two sheets of graphene oxide paper are bonded by means of an adhesive.

5. An electric device comprising:
the material of claim 1 .

6. The electric device of claim 5 , further comprising:
an element made from said material; and
at least a second material of a second conductivity/permittivity and a third material of a third conductivity/permittivity, where the second conductivity/permittivity is higher than the third permittivity/conductivity,
wherein said element is arranged to bridge the first second and second third further materials,
wherein said element has at least two surfaces of different conductivity and/or permittivity, and
wherein the high conductivity/permittivity surface of said element is in physical contact with the second material and the low conductivity/permittivity surface of said element is in physical contact with the third material.

7. The electric device of claim 6 , wherein the electric device is a cable accessory, wherein said element is arranged as an extension of a semiconducting layer into a joint insulation, and wherein a high conductivity/permittivity surface of said element is in physical contact with said semiconducting layer.

8. The electric device of claim 6 , wherein the electric device is a power cable having an insulation layer and at least one semiconducting layer, wherein said element is arranged between at least part of the insulation layer and at least one of the at least one semiconducting layers, and wherein a high conductivity/permittivity surface of said element is in physical contact with the at least one of the at least one semiconducting layers.

9. The electric device of claim 6 , further comprising:
an insulating spacer arranged to mechanically and electrically separate two parts of the device which are arranged to be at different electrical potential,
wherein said element forms at least part of the surface of the spacer in order to facilitate for electrical charges to leave the spacer, with a high conductivity/permittivity surface of said element facing the outside of the spacer.

10. The electric device of claim 6 , wherein the electric device is a microelectronics component comprising at least one electric contact, and wherein said element is arranged so that a high conductivity/permittivity surface of the element is in physical contact with the electric contact.

11. The electric device of claim 5 , wherein the electric device is a bushing.

12. The electric device of claim 6 , wherein said element is arranged to be in physical contact with at least one second element of the device, and wherein the material at the surface of said element, which faces the second material, has an electrical conductivity and/or permittivity which is of the same order of magnitude as the conductivity/permittivity of the second material.

13. An electrically insulating device comprising:
an element made from the material of claim 1 ,
wherein said element forms at least part of the surface of the device in order to facilitate for electrical charges to leave the device, with a high conductivity/permittivity surface of said element facing the outside of the device.

14. The electrically insulating device of claim 13 , wherein the device is an electrically insulating spacer arranged to mechanically and electrically separate two parts of a device which are arranged to be at different electrical potential.

15. A method of producing the material of claim 1 for electrical applications, the method comprising the step of:
treating different parts of a graphene oxide element differently, so as to achieve a different degree of reduction of the graphene oxide within the element, resulting in an element having a gradient in the electrical conductivity and/or permittivity, and
annealing for 1-120 minutes,
wherein the degree of reduction continuously increases through the material,
wherein at least one part of the element is exposed to irradiation by UV, laser, X-ray, or electron beam radiation, and
wherein the element has a thickness of 0.1-10 mm.

16. The method of claim 15 , wherein at least one part of the element is exposed to a first temperature and a second part of the element is exposed to a second temperature, so as to achieve a temperature gradient in the sample, and wherein the first and second temperatures are different, and at least one of the first and second temperatures is 130° C. or higher.

17. The method of claim 15 , wherein the graphene oxide element comprises a composite material having a polymer matrix and particle fillers of graphene oxide.

18. The method of claim 15 , wherein the graphene oxide element comprises graphene oxide paper.

Assignees

• Abb Technology Ltd
• Abb Schweiz Ag

Inventors

• Logakis Emmanuel
• Skordos Alex
• Chatzi Panagiota

Classifications

• H01B3/18

  mainly consisting of organic substances {(organic macromolecular compounds or compositions C08)} · CPC title

• B32B2307/202

  Conductive · CPC title

• H01B1/04 Primary

  mainly consisting of carbon-silicon compounds, carbon or silicon · CPC title

• Y10T428/30

  Self-sustaining carbon mass or layer with impregnant or other layer · CPC title

• B32B2250/40

  Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA · CPC title