Conductive ink comprising graphene

Abstract

The invention relates to a conductive ink comprising graphene, the ink comprising, in mass fraction, in the liquid state, between 20% and 40% graphene, 5% to 40% acrylic resin, and 10% to 30% solvents and 2% to 20% dispersant, and, in the solid state, at least 50% graphene, characterised in that it comprises metal pigments.

Description

[0001] CONDUCTIVE INK CONTAINING GRAPHENE

[0002] TECHNICAL FIELD

[0003] The present invention relates to a conductive ink comprising graphene, in particular a conductive ink arranged to conduct an electric current.

[0004] Graphene is a thin and strong material known to those skilled in the art. Graphene is a single layer of carbon atoms, tightly bound in a honeycomb-like crystal lattice, which is the basic structural element of industrial and manufacturing applications of carbon, including graphite, charcoal, and carbon nanotubes.

[0005] Today, it is very common to use graphite which is wrongly called graphene and the chemical properties of this material being difficult to control, the yield is not always there.

[0006] As a rule, today people mainly use inks using graphene with a low dosage of graphene.

[0007] STATE OF THE ART

[0008] Today, metals such as copper or silver are commonly used to conduct current. These metals are good conductors but are expensive.

[0009] SUMMARY OF THE INVENTION

[0010] The aim of the present invention is to propose a graphene-based conductive ink whose properties allow good conductivity, low thickness and controlled cost.

[0011] According to the present invention, a conductive ink comprising graphene comprises, in mass fraction, in the liquid state, between 20% and 40% of graphene, from 5% to 40% of acrylic resin and from 10% to 30% of solvents and 2 to 20% of dispersant, and in the solid state, at least 50% of graphene characterized in that it comprises metallic pigments. In one embodiment, the ink comprises between 5% and 25% of metallic pigments, in particular silver or copper pigments.

[0012] In a preferred embodiment, the graphene is composed of particles of at least two different particle sizes.

[0013] Still according to this preferred embodiment, the ink comprises particles with a particle size of 1 to 3 microns.

[0014] In one embodiment, the thickness of the ink, once dry, is less than 10 microns.

[0015] In one embodiment, the ink is arranged to heat when an electrical voltage is applied.

[0016] In another embodiment, the graphene is composed of at least two types of particles with different particle sizes.

[0017] According to this other embodiment, at least one of the graphene particles has a particle size of 1 to 3 microns.

[0018] In one form of application, the conductive ink is used to make a diode, a photovoltaic cell, a battery or an electrothermal sheet.

[0019] DETAILED DESCRIPTION OF THE INVENTION

[0020] In the context of the application of a conductive ink according to the present invention, on a multilayer electrothermal structure, or heating film, the conductive ink comprises in mass fraction, in the liquid state, between 20% and 30% of graphene, from 10% to 30% of acrylic resin and from 10% to 20% of solvents and 5% to 15% of dispersant, and in the solid state, at least between 50% and 60% of graphene as well as between 5% and 20% of silver metallic pigments.

[0021] The conductive ink applied to the heating film is arranged to conduct electrical energy between an anode and a cathode and thus supply current to the heating film. The conductive ink acts as electrodes. In this example, since the heating film must be as thin as possible, less than 0.4 mm, the graphene used in this conductive ink is composed of graphene particles with a particle size of 1 to 3 microns, and in some cases, at least two types of particles with different particle sizes, for example composed of graphene particles with a particle size of 1 to 3 microns and graphene particles with a particle size of 7 to 10 microns.

[0022] The conductive ink may be disposed on a film connected either to a direct current or to an alternating current, without having any impact on the heating performance of the heating film. Although the invention has been described according to a particular embodiment, it is in no way limited thereto, and variants may be made thereto, as well as combinations of the variants described concerning in particular the thickness of the ink on a support without departing from the scope of the present invention.

Claims

DEMANDS 1. Conductive ink comprising graphene, the ink comprising by mass fraction, in the liquid state, between 20% and 40% graphene, 5% to 40% acrylic resin and 10% to 30% solvents and 2% to 20% dispersant, and in the solid state, at least 50% graphene characterized in that it comprises metallic pigments.

2. Ink according to claim 1, comprising between 5% and 25% metallic pigments, in particular silver pigments.

3. Ink according to claim 1 or 2, characterized in that the graphene is composed of particles of at least two different particle sizes.

4. Ink according to claim 3, comprising particles with a particle size of 1 to 3 microns.

5. Ink according to any one of the preceding claims, the thickness of which, once dry, is less than 10 microns.

6. Use of the ink according to claims 1 to 5, for manufacturing a diode, a photovoltaic cell, a battery, an electrothermal sheet.