BG67400B1 - High voltage technology for production of graphene and its application as a surface coating on a metal substrate - Google Patents

Abstract

The 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

(54) HIGH VOLTAGE TECHNOLOGY FOR OBTAINING GRAPHENE AND ITS APPLICATION AS A SURFACE COATING ON A METAL SUBSTRATE.

Field of technique

The invention relates to the preparation 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 accumulating and storing energy by increasing the electrical and capacitive characteristics of electrodes used in electric batteries, accumulators and capacitors.

Prior art

Currently, technological research in the field of energy storage and storage is focused on the development of 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 mΩ. Therefore, they can accumulate and deliver this energy much faster and efficiently with an efficiency of around 95%. They also have several times higher charge-discharge currents, compared to standard electric batteries and accumulators. This advantage makes it possible to charge consumer devices in a very short time and generate very large discharge currents in a short time. Another main advantage of capacitors is that they have an almost infinite life - up to 1,000,000 charge and discharge cycles without loss of capacity, while the life of a storage battery 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.

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 directions in which work is being done to improve the capacitive characteristics of capacitors is through the use of nanographene structures [1], as a coating of capacitor electrodes.

These capacitors are called graphene supercapacitors (supercapacitors) and are passive electronic elements that can store electrical charge in significantly larger quantities. They have been talked about and worked on for a long time. Various technologies are being experimented with, thanks to which the super material graphene can unfold its full potential. Among the major manufacturers is Maxwell Technologies [2], which offers capacitors with capacities between 1 F and 3400 F at UR (Max Operating Voltage) from 2.7 V to 160 V, logically larger capacities having relatively small URs.

Technical essence of the invention

The essence of the invention consists in proposing 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 an anode and a carbon electrode acting as a cathode. The cathode, 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 the high voltage, exfoliate the carbon electrode into graphene sheets, which are layered on the metal surface, as a result of the potential difference between the cathode and the anode.

Graphite has a layered structure. It consists of many stacked sheets called graphene sheets, each of which is a set of stacked hexagonal structures. There are weak intermolecular interactions 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. 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 resulting coating.

The invention is illustrated by the following example of implementation

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

High-voltage sputtering and coating is carried out in a chamber in an inert gas environment, with the metal surface connected to the positive pole of a high-voltage current generator and a carbon electrode connected to the negative pole passed over it. The carbon electrode copies the shape of the treated surface, the distance above the surface, the speed of movement of the electrode, the strength of 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 one-dimensional case of the discharge, can be described by the following system of equations. [3-6]

BG 67400 Bl uU ₌ * ' gt-------» interne. I?

iao ⁺ fits (2) (3) (4) (5) where:

ne is electron concentration;

Po - concentration of neutral particles;

And _d - argon index;

r - reactive gas index;

σι - section of the ionized flux;

v _eo - frequency of elastic electron-atom collisions;

t _e - electron mass;

Schne - electronic frequency;

φ - electric potential;

T _is - electron temperature;

v ^(1+j) _eo - frequency of ionization and excitation by electron impacts;

V _e - velocity of electrons;

j - ion flux density.

The power of the discharge directly affects the energy of the electrons in the plasma flow and the rate of deposition of the coating. The increase in power, however, is accompanied by heating of the substrate surface. Heating is unacceptable for very thin pads. This is the reason that guides the determination of the values of the coating mode parameters.

The distance between the target and the substrate affects the deposition rate, coating structure, substrate temperature, etc. It is an important technological factor that is a function of the material and dimensions of the substrate, the strength and configuration of the high-voltage field, etc. If the distance is increased excessively, however, a decrease in the deposition rate and arc quenching occurs, resulting in reduced performance. Therefore, this parameter of the coating deposition process is determined experimentally for each specific case.

Claims (1)

High-voltage technology for graphene production and application, as a graphene coating on a metal substrate using electric arc technology, to increase the electrical and capacitive characteristics of electrodes used in electric batteries, accumulators and capacitors, characterized by the use of electric arc method , in an inert gas environment at a voltage of 15 kV, 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, the power of the arc being chosen to spray the graphite electrode and to deposit the graphene plates on the surface of the metal surface due to the difference of the electric potential between the substrate and the electrode