Direct electrochemical exfoliation method for producing graphene nanoplatelets from natural graphite

Abstract

Embodiments herein disclose a method for preparing Graphene Nanoplatelets (GNP) using an electrochemical cell (100). The method involves providing graphite powder into an electrode assembly and applying both Direct Current (DC) and pulse power supplies to the graphite powder electrodes. The temperature of the electrode assembly is regulated using an integrated cooling system (150). An electrolyte medium (160), comprising an aqueous solution with sulfate ions at a concentration of 1 M to 5 M, facilitates the exfoliation of graphite powder into GNP. The method utilizes both anodic and cathodic exfoliation concepts to enhance the exfoliation process. The exfoliated GNP is collected from the electrolyte medium (160). This method produces GNP without the use of chemicals.

Description

DIRECT ELECTROCHEMICAL EXFOLIATION METHOD FOR PRODUCING GRAPHENE NANOPLATELETS FROM NATURAL GRAPHITEFIELD OF THE INVENTION

[0001] This invention relates to the field of nanotechnology, and more particularly to the production of graphene and Graphene Nanoplatelets (GNP) from natural graphite using an electro-exfoliation process.BACKGROUND OF THE INVENTION

[0002] Electrochemical exfoliation is a widely used technique to synthesize Graphene Nanoplatelets (GNP), graphene, and their derivatives from natural graphite. The process involves the electrolysis of water, where water molecules are split into hydrogen and oxygen gases at the cathode and anode, respectively.

[0003] However, due to the low electrical conductivity of water, rapid exfoliation is challenging. To enhance the process, acids and salts are used as electrolytes to improve electrical conductivity and increase oxygen evolution at the anode. Despite these improvements, conventional techniques face challenges such as the breaking of graphite electrodes into partially exfoliated particles, making it difficult to produce highly exfoliated GNP.

[0004] Existing approaches disclose a method for producing graphene but do not disclose the use of a device designed to trap graphite powder or the use of both direct and alternative (pulse) power supplies for exfoliation. They describe a process for continuously preparing graphene oxide nanoplatelets but lack the disclosure of a device designed to trap graphite powder and the elimination of chemicals in the exfoliation process.

[0005] Existing techniques provide a method for producing nano-scale graphene platelets but do not disclose the use of a device designed to trap graphite powder or the use of both direct and alternative (pulse) power supplies. They focus on the production of graphene but do not disclose the use of a device designed to trap graphite powder or the elimination of chemicals in the exfoliation process.

[0006] Lastly, existing methods describe a technique for producing graphene but lack the disclosure of a device designed to trap graphite powder and the use of both direct and alternative (pulse) power supplies for exfoliation.

[0007] The present invention introduces an electrochemical cell and method for electroexfoliating graphite powder to produce graphene and GNP without using chemicals.

[0008] This cost-effective, environmentally friendly, and scalable solution addresses the limitations of conventional techniques.

[0009] The invention stands out by trapping graphite powder, using both direct and alternative (pulse) power supplies, and eliminating the need for chemicals, making it more efficient and eco-friendlier compared to existing methods.OBJECT OF THE INVENTION

[0001] The main objective of the invention is to disclose a method and a device that can efficiently convert natural graphite powders into graphene and Graphene Nanoplatelets (GNP) using an electro-exfoliation process.

[0002] Another objective of the present invention is to provide a cost-effective and environmentally friendly solution by eliminating the use of chemicals traditionally required in the exfoliation process.

[0003] Yet another objective of the present invention is to improve the efficiency and effectiveness of the exfoliation process, resulting in highly exfoliated GNP, by using both direct and alternative (pulse) power supplies.

[0004] Another objective of the present invention is to offer a scalable solution that can be easily manufactured and scaled up for large-scale production of graphene and GNP, making it economically important for advanced graphene production.

[0005] Another objective of the present invention seeks to overcome the challenges faced by conventional methods, such as the breaking of graphite electrodes into partially exfoliated particles, by introducing a device that traps graphite powder and uniformly distributes the current.

[0006] Lastly, another objective of the present invention is to incorporate both anodic and cathodic exfoliation concepts to enhance the exfoliation process and achieve better results.SUMMARY OF THE INVENTION

[0010] In an aspect of the present invention, an electrochemical cell for preparing Graphene Nanoplatelets (GNP) including a nonconductive outer shell for structural integrity and electrical insulation is disclosed.

[0011] In the embodiment of the present invention, the cell features an anode and cathode configuration module where, for a Direct Current (DC) system, the anode is a graphite powder electrode. The cathode is made of a conductive material selected from metal and graphite rods. For a pulse system, both the anode and cathode are graphite powder electrodes.

[0012] Additionally, the cell includes a graphite conductive disk electrode to supply power to the graphite powder electrodes in both DC and pulse systems. A nonconductive mesh at the bottom of the electrode assembly retains the graphite powder while allowing the passage of exfoliated graphene, gases, and ions.

[0013] Further, the cooling system integrated with the electrode assembly regulates the temperature of high-capacitive electrodes during operation. The electrolyte medium is an aqueous solution containing sulfate ions at a concentration of 1 M to 5 M. The power supply system is configured to operate in DC mode.

[0014] In an aspect of the present invention, a method for preparing GNP, which involves providing graphite powder into the electrode assembly of the electrochemical cell.

[0015] In the embodiment of the present invention, both DC and pulse power supplies are applied to the graphite powder electrodes. The temperature of the electrode assembly is regulated using the integrated cooling system.

[0016] Further, the electrolyte medium, comprising an aqueous solution with sulfate ions at a concentration of 1 M to 5 M, facilitates the exfoliation of graphite powder into GNP. Both anodic and cathodic exfoliation concepts are utilized to enhance the exfoliation process.

[0017] In the embodiment of the present invention, the exfoliated GNP is collected from the electrolyte medium. The method produces GNP without the use of chemicals.

[0018] Further, the graphite powder is mined and powdered directly before use. The electrolyte medium is selected from sulfate ion-containing salts such as ammonium sulfate and sodium sulfate.

[0019] Further, the said process duration includes an initial expansion phase at low voltage for approximately 2 hours. This is followed by an exfoliation phase at a higher voltage for 12 to 72 hours. The cooling system maintains the temperature between 25°C and 60°C during operation.DESCRIPTION OF THE DRAWINGS

[0020] The advantages and features of the present invention will become better understood with reference to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0021] FIG. 1 is a schematic diagram of an electrochemical cell designed for preparing Graphene Nanoplatelets (GNP), according to embodiments as disclosed herein;

[0022] FIG. 2 is a detailed cross-sectional diagram of the electrochemical cell designed for preparing GNP, according to embodiments as disclosed herein;

[0023] FIG. 3 consists of two diagrams (3A and 3B) illustrating the setup of the electrochemical cell with a graphite powder electrode, according to embodiments as disclosed herein;

[0024] FIG. 4 illustrates two different configurations of the electrochemical cell using graphite powder electrodes and an Alternating Current (AC) power supply, according to embodiments as disclosed herein;

[0025] FIG. 5 depicts four Transmission Electron Microscopy (TEM) images of a sample at different magnifications, according to embodiments as disclosed herein;

[0026] FIG. 6 shows Raman spectra for three different samples: Bogala 40 pm graphite, a freeze-dried sample, and a vacuum-dried sample, according to embodiments as disclosed herein;

[0027] FIG. 7 shows two Scanning Electron Microscope (SEM) images (7A and 7B) of a material at different magnifications, according to embodiments as disclosed herein;

[0028] FIG. 8 consists of four sets of images and corresponding graphs, each representing different samples or conditions, according to embodiments as disclosed herein; and

[0029] FIG. 9 is a flowchart depicting a method for preparing GNP, according to embodiments as disclosed herein.Like numerals denote like elements throughout the figures.DESCRIPTION OF THE INVENTION

[0030] The exemplary embodiments described herein detail for illustrative purposes are subjected to many variations. It should be emphasized, however, that the present invention is not limited to as disclosed.

[0031] It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the scope of the present invention.

[0032] Specifically, the following terms have the meanings indicated below.

[0033] The terms “a” and “an” herein do not denote a limitation of quantity but rather denote the presence of at least one of the referenced items.

[0034] The terms “having”, “comprising”, “including”, and variations thereof signify the presence of a component.

[0035] The inventive aspects of the invention along with various components and engineering involved will now be explained with reference to Figs. 1-9 herein.

[0036] In an aspect of the invention, a method and an electrochemical cell designed for preparing Graphene Nanoplatelets (GNP). It includes a nonconductive outer shell for structural integrity and electrical insulation is disclosed. The invention offers a simple, cost-effective, and environmentally friendly technology that enhances the electrochemical exfoliation process by uniformly distributing current and enabling the use of both direct and pulse power supplies.

[0037] The electrochemical exfoliation method involves applying an electric current to a bulk material in an electrolyte solution to produce 2D materials like graphene. The process can separate the layers of the material, resulting in nanoplatelets with a thickness of less than 100 nm. This method is simple, fast, and scalable for producing high-quality 2D materials.

[0038] The invention eliminates the need for chemical use in exfoliation, reduces production costs, and provides a scalable solution for advanced graphene production through an easy-to-manufacture electro-exfoliation reactor.

[0039] The present invention also mentions a prototype designed to convert mined and powdered graphite directly into GNP or graphene. The electrochemical cell includes an electrode prototype that traps graphite powder, supports the connection to a power supply, and enhances electrochemical exfoliation.

[0040] The cell uniformly distributes the current, allowing for efficient exfoliation, and various cell arrangements are possible with both direct and pulse power supplies.

[0041] FIG. 1 is a schematic diagram of an electrochemical cell 100 designed for preparing Graphene Nanoplatelets (GNP). The electrochemical cell 100 comprises a nonconductive outer shell 110, an anode and a cathode configuration module 120, a graphite conductive disk electrode 130, a nonconductive mesh 140, a cooling system 150, an electrolyte medium 160, and a power supply system 170.

[0042] The nonconductive outer shell 110 provides structural integrity and electrical insulation for the electrochemical cell 100. It can be made from materials such as Teflon, Polyvinyl Chloride (PVC), Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Low-Density Polyethylene (LDPE), ceramic, or ceramic-coated metal material.

[0043] The anode and cathode configuration module 120 comprises an anode and a cathode. The anode comprises a graphite powder electrode, and the cathode comprises a conductivematerial selected from metal and graphite rods for a Direct Current (DC) system. For a pulse system, both the anode and the cathode comprise graphite powder electrodes.

[0044] The graphite conductive disk electrode 130 is configured to supply power to the graphite powder electrodes in both the DC and pulse systems. The nonconductive mesh 140 is positioned at the bottom of the electrode assembly, designed to retain the graphite powder while allowing the passage of exfoliated graphene, generated gases, and ions.

[0045] The cooling system 150 is integrated with the electrode assembly to regulate the temperature of high-capacitive electrodes during operation, maintaining the temperature between 25 °C and 60°C. The electrolyte medium 160 comprises an aqueous solution containing sulfate ions at a concentration of 1 M to 5 M, selected from sulfate ion-containing salts such as ammonium sulfate and sodium sulfate.

[0046] The power supply system 170 operates in DC mode at a voltage range of 1.8V to 24V and provides a current greater than 0.5A. In pulse mode, it uses a square wave signal with a frequency of approximately 1 Hz and a voltage configured to sustain a current greater than 0.5A. The process includes an initial expansion phase at low voltage (1.8V to 2V) for approximately 2 hours, followed by an exfoliation phase at higher voltage (12V to 24V) for 12 to 72 hours.

[0047] Although FIG. 1 shows various hardware components of the electrochemical cell 100, it is to be understood that other embodiments are not limited thereto. In other embodiments, the electrochemical cell 100 may include fewer or more components. Further, the labels or names of the components are used only for illustrative purposes and do not limit the scope of the invention. One or more components can be combined to perform the same or substantially similar function in the electrochemical cell 100.

[0048] FIG. 2 is a detailed cross-sectional diagram 200 of the electrochemical cell 100 designed for preparing GNP. The electrochemical cell 100 comprises several key components, each labeled with its respective reference numerals.

[0049] At the top, the electrochemical cell 100 includes a piston cover 202, which houses a pressure-controlling spring or unit 204. Below this is the power connection 206, which is linked to the piston 208.

[0050] The piston is surrounded by electrode cooling lines 210, ensuring the device remains at an optimal temperature during operation. The outer cylinder 212 encases these components, providing structural support.

[0051] At the bottom of the piston, there is a carbon-coated metal or carbon disk 214, which is in contact with graphite powder 216. This assembly is held together by a mesh and holding unit 218 at the base.

[0052] The dimensions of the electrochemical cell 100 are also provided. The total height is 355 mm (80 mm for the piston cover 202, 200 mm for the main body, and 75 mm for the bottom section). The width is 75 mm, with the inner section being 60 mm wide.

[0053] FIG. 3 consists of two diagrams (3A and 3B) illustrating the setup of an electrochemical cell with a graphite powder electrode. In the top diagram (FIG. 3A), the graphite powder electrode is connected to the positive terminal of a DC power supply, making it the anode. The electrolyte surrounds the graphite powder electrode, and a separate cylindrical electrode is connected to the negative terminal of the DC power supply, making it the cathode. The electrolyte facilitates the movement of ions between the anode and cathode.

[0054] In the bottom diagram (FIG. 3B), the setup is similar but with a different orientation. The graphite powder electrode is still connected to the positive terminal of the DC power supply, serving as the anode. The electrolyte flows into the cell, surrounding the graphite powder electrode. The cylindrical electrode, connected to the negative terminal of the DC power supply, serves as the cathode.

[0055] The electrochemical cell 100 is used for various applications, such as energy storage, electrolysis, or electroplating. The use of a graphite powder electrode can enhance the surface area and improve the efficiency of the electrochemical reactions.

[0056] FIG. 4 illustrates two different configurations of an electrochemical cell using graphite powder electrodes and an Alternating Current (AC) power supply. In the first diagram (4A), two graphite powder electrodes are immersed in an electrolyte solution. The electrodes are connected to an AC power supply, indicated by the sinusoidal waveform symbol. The AC power supply is connected to the top of the electrodes via red wires. The electrolyte solution is depicted as a blue liquid surrounding the lower part of the electrodes. Arrows indicate the direction of current flow through the electrodes and the electrolyte.

[0057] In the second diagram (4B), the setup is similar, but the orientation of the electrodes and the electrolyte container are different. The electrolyte is shown as a blue liquid filling a container, with the graphite powder electrodes partially submerged in it. The AC power supply is again connected to the electrodes via red wires, with the sinusoidal waveform symbol indicating the alternating current.

[0058] FIG. 4A and FIG. 4B illustrate the configuration of an electrochemical cell using graphite powder electrodes and an AC power supply, which can be used in various applications such as energy storage, electrolysis, or electrochemical synthesis. The use of an AC power supply and graphite powder electrodes can offer advantages in terms of efficiency and performance in these applications.

[0059] FIG. 5 depicts four Transmission Electron Microscopy (TEM) images of a sample at different magnifications. The top two images (5A and 5B) have a scale bar of 0.5 pm, showing structures in the micrometer range.

[0060] The bottom left image (5C) has a scale bar of 200 nm, and the bottom right image (5D) has a scale bar of 100 nm, revealing finer details.

[0061] The images display various irregularly shaped, layered, and possibly fragmented materials. These structures at different magnifications help analyze the morphology and size distribution of the sample, which is crucial for understanding its physical properties,composition, or potential applications in fields like materials science, nanotechnology, or biology.

[0062] The varying scales provide a comprehensive view of the sample's microstructure, highlighting both larger aggregates and finer details.

[0063] FIG. 6 shows Raman spectra for three different samples: Bogala 40 pm graphite, a freeze-dried sample, and a vacuum-dried sample. Each spectrum displays the intensity of Raman scattering (y-axis) as a function of the Raman shift (x-axis) in cmA-l. The spectra are color-coded: blue for Bogala 40 pm graphite, red for the freeze-dried sample, and green for the vacuum-dried sample.

[0064] Key peaks in the spectra are labeled, and the ID / IG ratios are provided for each sample. The ID / IG ratio measures the disorder in the graphite structure, with lower values indicating more ordered graphite. The Bogala 40 pm graphite has an ID / IG ratio of 0.28, indicating a relatively ordered structure.

[0065] The freeze-dried sample has an ID / IG ratio of 0.67, and the vacuum-dried sample has an ID / IG ratio of 0.64, both indicating higher levels of disorder compared to the Bogala graphite.

[0066] FIG. 6 shows the structural differences in graphite and graphite -derived materials subjected to different drying processes.

[0067] FIG. 7 shows two Scanning Electron Microscope (SEM) images (7A and 7B) of a material at different magnifications. The left image (7 A) is taken at a magnification of 600x, while the right image (7B) is taken at a magnification of 10,000x.

[0068] Both images are labeled with the equipment used (SU6600), the accelerating voltage (15.0 kV), the working distance (9.2 mm for the left image and 9.8 mm for the right image), and the date of capture (March 4, 2022, for the left image (7 A) and March 1, 2022, for the right image (7B)).

[0069] The scale bars at the bottom of each image indicate the size of the features being observed, with the left image (7 A) showing a scale of 50.0 pm and the right image showing a scale of 5.00 pm.

[0070] The left image (7 A) reveals larger, more defined flakes or particles, while the right image (7B), at a higher magnification, shows a more detailed and intricate structure of the material, highlighting finer features and textures.

[0071] These images (7A and 7B) provide detailed insights into the microstructure of the material, which can be crucial for understanding its properties and potential applications.

[0072] FIG. 8 consists of four sets of images and corresponding graphs, each representing different samples or conditions. Each set includes an Atomic Force Microscopy (AFM) image on the left, a line profile graph in the middle, and a power spectrum graph on the right. The first set shows an AFM image with a scale bar indicating nanometers (nm) on the y-axis and micrometers (pm) on the x-axis. The line profile graph in red shows the height variation along a specific line on the AFM image, with the x-axis in micrometers and the y-axis in nanometers. The power spectrum graph in red shows the frequency distribution of the surface features, with the x-axis in micrometers and the y-axis in arbitrary units.

[0073] The second set shows an AFM image with a similar scale bar. The line profile graph in red shows the height variation along a specific line on the AFM image, with the x-axis in micrometers and the y-axis in nanometers. Additionally, there is a green line profile graph showing another height variation along a different line on the AFM image. The power spectrum graph in red shows the frequency distribution of the surface features.

[0074] The third set shows an AFM image with a similar scale bar. The line profile graph in red shows the height variation along a specific line on the AFM image, with the x-axis in nanometers and the y-axis in nanometers. The power spectrum graph in red shows the frequency distribution of the surface features.

[0075] The fourth set shows an AFM image with a similar scale bar. The line profile graph in red shows the height variation along a specific line on the AFM image, with the x-axis in micrometers and the y-axis in nanometers. The power spectrum graph in red shows the frequency distribution of the surface features.

[0076] FIG. 8 provide detailed information about the surface topography and roughness of different samples, which can be crucial for understanding material properties and performance in various applications.

[0077] FIG. 9 is a flowchart depicting a method 900 for preparing GNP. At step 902, the process begins by providing graphite powder into the electrode assembly of the electrochemical cell 100. The graphite powder is mined and powdered directly before being used in the electrochemical exfoliation process.

[0078] At step 904, both DC and pulse power supplies are applied to the graphite powder electrodes using the electrochemical cell 100. The pulse mode of the power supply system (170) uses a square wave signal with a frequency of approximately 1 Hz and a voltage configured to sustain a current greater than 0.5A.

[0079] At step 906, the temperature of the electrode assembly is regulated using an integrated cooling system 150 within the electrochemical cell 100. The cooling system is configured to maintain the temperature between 25 °C and 60°C during operation.

[0080] At step 908, the electrolyte medium 160, which is an aqueous solution containing sulfate ions at a concentration of 1 M to 5 M, is allowed to facilitate the exfoliation of graphite powder into GNP. The electrolyte medium is selected from sulfate ion-containing salts such as ammonium sulfate and sodium sulfate.

[0081] At step 910, both anodic and cathodic exfoliation concepts are utilized by the electrochemical cell 100 to enhance the exfoliation process.

[0082] At step 912, the exfoliated GNP is collected from the electrolyte medium 160 by the electrochemical cell 100. At step 914, the electrochemical cell 100 produces GNP without the use of chemicals.

[0083] The various actions in method 900 may be performed in the order presented, in a different order, or simultaneously. Further, in some embodiments, some actions listed in FIG. 9 may be omitted.ADVANTAGEOUS EFFECT OF THE INVENTION

[0084] In the embodiment of the present invention, the electrochemical cell 100 for preparing GNP offers several advantageous effects. Firstly, it allows for the efficient production of GNP without the use of harmful chemicals, making it an environmentally friendly process.

[0085] Further, the method utilizes both anodic and cathodic exfoliation concepts, which enhance the exfoliation process and result in high-quality GNP with excellent properties.

[0086] In the embodiment of the present invention, the integrated cooling system 150 ensures that the temperature of the electrode assembly is regulated, maintaining optimal conditions for the exfoliation process.

[0087] Additionally, the use of a nonconductive mesh 110 allows for the retention of graphite powder while permitting the passage of exfoliated graphene, gases, and ions, thereby improving the overall efficiency of the process.

[0088] In the embodiment of the present invention, the power supply system 170, capable of operating in both DC and pulse modes, provides flexibility and control over the exfoliation process.

[0089] In a nutshell, the present invention provides a cost-effective, efficient, and environmentally friendly method for producing high-quality GNP.

[0090] It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

[0091] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously, many modifications and variations are possible in light of the above teaching.

[0092] Further, the embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated.

Claims

CLAIMS:

1. An electrochemical cell (100) for preparing Graphene Nanoplatelets (GNP), comprising: a nonconductive outer shell (100) to provide structural integrity and electrical insulation; an anode and cathode configuration module (120) configured such that:for a Direct Current (DC) system, the anode comprises a graphite powder electrode, while the cathode is made of a conductive material selected from at least one of a metal and graphite rods;for a pulse system, both the anode and the cathode comprise graphite powder electrodes; a graphite conductive disk electrode (130) configured to supply power to the graphite powder electrodes in both the DC and pulse system;a nonconductive mesh (140) positioned at the bottom of an electrode assembly, configured to retain the graphite powder while allowing the passage of exfoliated graphene, generated gases, and ions;a cooling system (150) integrated with the electrode assembly to regulate the temperature of high-capacitive electrodes during operation;an electrolyte medium (160) comprising an aqueous solution containing sulfate ions at a concentration of 1 M to 5 M; anda power supply system (170) configured to operate in DC mode.

2. The electrochemical cell (100) as claimed in claim 1, wherein the nonconductive outer shell (110) minimizes electrical interference and chemical degradation, utilizing materials specifically selected for their resistance to high-temperature and corrosive environments during the exfoliation process.

3. The electrochemical cell (100) as claimed in claim 1, wherein the power supply system (170) is uniquely configured to deliver a precise voltage range of 1.8V to 24V, combined with asustained current exceeding 0.5 A, ensuring consistent exfoliation and uniform distribution of current across the graphite powder electrodes.

4. The electrochemical cell (100) as claimed in claim 1, wherein the nonconductive outer shell (110) is made from a Teflon, Polyvinyl Chloride (PVC), Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Low-Density Polyethylene (LDPE), ceramic, or ceramic-coated metal material.

5. The electrochemical cell (100) as claimed in claim 1, wherein the pulse mode of the power supply system (170) uses a square wave signal with a frequency of approximately 1 Hz and a voltage configured to sustain a current greater than 0.5 A.

6. The electrochemical cell (100) as claimed in claim 1, wherein the electrode assembly further includes a nonconductive mesh designed to support the graphite powder while permitting the passage of exfoliated graphene, gases, and ions.

7. The electrochemical cell (100) as claimed in claim 1, wherein the cooling system (100) integrated with the electrode assembly is configured to maintain the temperature between 25°C and 60°C during operation.

8. The electrochemical cell (100) as claimed in claim 1, wherein the electrolyte medium (160) is selected from sulfate ion-containing salts comprising ammonium sulfate and sodium sulfate at a concentration range of about 1 M to 5 M.

9. The electrochemical cell (100) as claimed in claim 1, wherein the process duration for exfoliation includes an initial expansion phase at low voltage (1.8V to 2V) for approximately 2 hours, followed by an exfoliation phase at higher voltage (12V to 24V) for 12 to 72 hours.

10. A method for preparing Graphene Nanoplatelets (GNP) using an electrochemical cell (100) comprising a nonconductive outer shell (110), an anode and cathode configuration module (120),a graphite conductive disk electrode (130), a nonconductive mesh (140), a cooling system (150), an electrolyte medium (160), and a power supply system (170), the method comprises: providing graphite powder into an electrode assembly;applying both Direct Current (DC) and pulse power supplies to the graphite powder electrodes;regulating the temperature of the electrode assembly using an integrated cooling system (150); allowing an electrolyte medium (160), comprising an aqueous solution containing sulfate ions at a concentration of 1 M to 5 M, to facilitate the exfoliation of graphite powder into GNP; utilizing both anodic and cathodic exfoliation concepts to enhance the exfoliation process; collecting the exfoliated GNP from the electrolyte medium (160); andproducing GNP without the use of chemicals.

11. The method as claimed in claim 10, wherein the electrolyte medium (160) is selected from sulfate ion-containing salts such as ammonium sulfate and sodium sulphate at a concentration range of 1 M to 5 M.

12. The method as claimed in claim 10, wherein the process duration for exfoliation includes an initial expansion phase at low voltage (1.8V to 2V) for approximately 2 hours, followed by an exfoliation phase at higher voltage (12V to 24V) for 12 to 72 hours.

13. The method as claimed in claim 10, wherein the cooling system (150) integrated with the electrode assembly is configured to maintain the temperature between 25 °C and 60°C during operation.

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