BG112894A - High voltage technology for production of graphene and its application as a surface coating on a metal substrate - Google Patents

Abstract

The present invention provides a technology for producing graphene and applying it as a graphene coating to a metal substrate using electric arc technology in order to increase the electrical and capacitive characteristics of the electrodes used in electric batteries, accumulators and capacitors. For this purpose, an electric arc method is implemented, in an inert gas environment, in which the arc generated by a high-voltage generator is formed between the metal surface acting as an anode and a carbon electrode acting as a cathode. When the arc is turned on, the cathode emits a stream of electrons that bombard the anode with a temperature of about 4000 K, and simultaneously under the influence of high voltage stratify the carbon electrode into graphene plates, which are deposited on the metal surface due to the potential difference between the cathode and the anode and thus create a monograph layer.

Description

HIGH VOLTAGE TECHNOLOGY FOR GRAPHEN PRODUCTION AND ITS APPLICATION AS A SURFACE COATING ON A METAL SUBSTRATE.

FIELD OF THE INVENTION

The patent relates to the production of graphene and its application as a graphene coating on a metal substrate using electric arc technology and is in the field of technologies for storage and storage of energy by increasing the electrical and capacitive characteristics of electrodes used in electric batteries, accumulators and capacitors.

BACKGROUND OF THE INVENTION

Currently, technological research in the field of energy storage and storage is aimed at developing high-capacity electric batteries, accumulators and capacitors.

Unlike batteries, capacitors store energy not through chemical processes but electrostatically and are characterized by an internal active resistance of the order of πιΩ. Therefore, they can accumulate and deliver this energy much faster and more efficiently with an efficiency of about 95%. They also have many times higher charging and discharging currents compared to standard electric batteries and accumulators. This advantage allows you to charge consumer devices in a very short time and generate very large discharge currents in a short time. Another major advantage of capacitors is that they have an almost infinite life - up to 1,000,000 cycles of charge and discharge without loss of capacity, while the battery life is a maximum of about 5,000 cycles.

The main disadvantage of capacitors is that the energy they accumulate is tens of times less than that of batteries and accumulators. - 1 For example, a standard rechargeable battery, at an operating voltage of 1.2 V and a current of 850 mAh, accumulates energy of about 3600 J, while the energy accumulated by a capacitor with a capacity of 100 pF / 450 V is about 10 J.

One of the areas in which work is being done to improve the capacitive characteristics of the capacitors is through the use of nanographene structures (Fig.

1) [1], as a coating on the electrodes of the capacitors.

FIG. 1 Structure of graphene

These capacitors are called graphene supercapacitors and are passive electronic components that can store electrical charges in much larger quantities. They have been talked about and worked on for a long time. Experimenting with different technologies, thanks to which the supermaterial graphene to reach its full potential. Among the major manufacturers is Maxwell Technologies [2], which offers capacitors with a capacity between 1 F and 3400 F at UR (Max Operating Voltage) from 2.7 V to 160 V, with logically larger capacities with relatively small UR.

TECHNICAL ESSENCE

The essence of the patent is that it offers a technology for forming and applying a monolayer of graphene coating on a metal substrate, consisting in using an electric arc method in an inert gas environment in which the arc generated by a high-voltage generator , is formed between the metal surface acting as the anode and the carbon electrode acting as the cathode. When the arc is turned on, the arc emits a stream of electrons that bombard the anode with a temperature of about 4000 K, and at the same time, under the influence of high voltage, stratify the carbon electrode into graphene plates, which are deposited on the metal surface.

Carbon is characterized by the fact that there are 6 protons in its nucleus and 6 electrons in the electron cloud around it (Fig. 2).

2r _{x 2ru}

2Pz

1C

FIG. 2 Energy structure of the carbon atom

This is possible only if the four types of orbitals on which the valence electrons are located interact in some way, until four new and identical orbitals are obtained. This process is called "hybridization", and the newly obtained orbitals are hybrid orbitals. Different degree of hybridization is possible - sp (between one s and one p orbital), sp2 (one s and

-3two p orbitals) and sp3 (one s and three p _; orbitals) (Fig. 3). Different hybridization leads to different properties.

overlap of sp ² and p orbitals

tg-bond

—......... f>

ethylene

FIG. 3 Hybrid carbon orbitals

In graphite (Fig. 4), the carbon atoms are in the sp2 hybrid state, which means that three of the four atomic orbitals interacted with each other to form three new identical hybrid orbitals, and one single "p" orbital remained unchanged. The interaction between two such carbon atoms forms a double bond - one component to it is obtained by the overlap of two of the hybridized orbitals along the axis that connects the two carbon nuclei, and the other - by the overlap below and above the axis of the two unhybridized "p" orbitals. The electrons that belong to this second bond are more easily bound to the nucleus.

FIG. 4 Graphite structure (hexagonal lattice)

In a system such as graphite, which contains a large number of carbon atoms, a large number of double bonds are formed. This structure is characterized by high delocalization of electrons. They can circulate freely in the "channels" formed by the overlap of the unhybridized orbitals and are not strictly fixed to one atom, which explains the electrical conductivity of graphite.

Therefore, graphite has a layered structure. It consists of a plurality of stacked planes called graphene, each of which is a plurality of adhered hexagonal structures. Weak intermolecular interactions act between the individual planes and this allows them to be easily separated from each other under the action of the high-voltage voltage generated between the carbon electrode and the metal base.

The voltage between the metal substrate and the graphite electrode is generated by a high-voltage generator operating at a voltage of 15 kV. The technological modes of operation are selected depending on the distance between the electrode and the substrate, the area of the substrate, the speed of movement of the graphite electrode and the thickness of the obtained coating.

-5PATENT IS EXPLAINED WITH THE FOLLOWING EXAMPLE OF EXECUTION

The metal surface of the pad is mechanically cleaned to remove coarse dirt using abrasive materials and cleaning wipes. After mechanical cleaning, the surface is cleaned and chemically, to remove organic contaminants, with detergent and warm water, followed by rinsing with distilled water and drying with warm air.

The high-voltage spraying and coating is performed in a chamber in an inert gas environment, the metal surface is connected to the positive pole of a high-voltage current generator and a carbon electrode connected to the negative pole is passed over it. The carbon electrode copies the shape of the treated surface, the distance above the surface, the speed of the electrode, the current and the voltage determine the characteristics of the resulting coating, which can be from a few micrometers to 0.5 mm.

The magnitude of the flow of charged particles, in the case of a one-dimensional case of the discharge, can be described by the following system of equations. [3-6] £ (nX *) = + n _e n ^r ₀ (a [Vjy, (1) irχ ________.

г / Ъ \)

17U __ 1GH.

‘D t

e ² .grad ² φ

2t _in t ₀₊ In _in0

Veo ^w eo (2) (3) (4) (5) where:

n _is the electron concentration;

n ₀ - concentration of neutral particles;

Ag - argon index;

d - index of reactive gas;

σ _; - cross section of the ionized flow;

v _eo - frequency of elastic electron-atom collisions;

t _e - mass of the electron;

sleep _is - electronic frequency;

φ - electric potential;

T _e - electron temperature;

V ^{l + j)} _eo - frequency of ionization and excitation by electron shocks;

V _e - velocity of the electrons;

j - ion flux density.

The power of the discharge directly affects the energy of the electrons in the plasma flux and the rate of deposition of the coating. The increase in power, however, is accompanied by heating of the substrate surface. Heating is not allowed for very thin pads. This is the reason that is leading in determining the values of the parameters of the coating mode.

The distance between the target and the substrate affects the deposition rate, the structure of the coating, the temperature of the substrate and others. It is an important technological factor, which is a function of the material and dimensions of the substrate, the strength and configuration of the high-voltage field and more. However, with an excessive increase in distance, there is a decrease in the rate of deposition and quenching

-7 volt arc, which leads to reduced performance. Therefore, this parameter of the coating deposition process is determined experimentally on a case-by-case basis.

Acknowledgments: This patent is thanks to the financial support of the Ministry of Education and Science in the implementation of the National Scientific Program Low Carbon Energy for Transport and Life - E Plus, approved by decision of MC # 577 / 17.08.2018.

LITERATURE

1. Sung Hoon Jung, Yusik Myung, Bit Na Kim, In Gyoo Kim, In-Kyu You, Tae Young Kim, Activated Biomass-derived Graphene-based Carbons for Supercapacitors with High Energy and Power Density, Scientific Reports volume 8, Article number : 1915 (2018).

2. C. Kutsarov, Modern capacitive components, Electronics,

Mr. Engineering Review, no. 4,2016.

3. R. Milusheva: Metal coatings on polymeric materials. PhD thesis, 2016.

4. Barabash Ο., Y. Koval. Crystalline structure of metal and alloys. - Kiev: Science, 1986.

5. Zaborin, AG, Pipkevich GJ, Research on Heat and Mass Exchange in Processes of Metallized Pigmentation and Concentration in Vacuum, Metallization in Vacuum, Riga, 1993, pp. 34

6. Cavaleiro, A., C. LouroQ Nanocrystalline structure and hardness of thin films, Vacuum, Volume 64, Issues 3-4, January 2002, Pages 211-218.

Claims (1)

COPYRIGHT CLAIMS 1. Preparation of graphene and its application as a graphene coating on a metal substrate using electric arc technology, to increase the electrical and capacitive characteristics of the electrodes used in electric batteries, accumulators and capacitors, characterized in that an electric arc method is used, in an inert gas medium in which the arc generated by a high-voltage generator is formed between the metal surface acting as the anode and the carbon electrode acting as the cathode, which, when the arc is turned on, emits a stream of electrons that bombard the anode with a temperature of about 4000 K ., and at the same time under the influence of high voltage, the carbon electrode is stratified into graphene planes, which are layered on the metal surface, due to the potential difference between the cathode and the anode and form a monograph layer.