KR-20260065674-A - NON-OXIDIZED-REDUCED GRAPHENE INK USING EXPANDED GRAPHITE AND MANUFACTURING METHOD THEREOF

Abstract

The present invention relates to a graphene ink utilizing expanded graphite and a method for manufacturing the same. More specifically, it relates to a method for manufacturing graphene ink in which a graphene layer is separated by applying thermal shock to expanded graphite, and an organic dispersant and a thickener capable of effectively dispersing the graphene exfoliated from the expanded graphite are discovered to establish optimal conditions for manufacturing graphene ink.

Inventors

• 김성욱
• 전기완

Assignees

• 신라대학교 산학협력단

Dates

Publication Date

20260511

Application Date

20241101

Claims (10)

1. Step of placing expanded graphite into an alumina crucible and setting the temperature; A step of placing a crucible containing the expanded graphite into an electric furnace after reaching the set temperature and applying a thermal shock to exfoliate graphene from the expanded graphite; A step of preparing an organic vehicle by mixing a dispersant, a thickener, and distilled water; A method for manufacturing graphene ink characterized by including the step of mixing the above organic vehicle and the above graphene to manufacture graphene ink.
2. In paragraph 1, In the step of placing the expanded graphite into an alumina crucible and setting the temperature, A method for manufacturing graphene ink characterized by the above temperature being 650 to 950 ℃.
3. In paragraph 1, In the step of exfoliating graphene from expanded graphite by placing the crucible containing the expanded graphite into an electric furnace after reaching the above-set temperature and applying thermal shock, A method for manufacturing graphene ink characterized by the above thermal shock being carried out for 1 to 10 minutes.
4. In paragraph 1, The step of preparing an organic vehicle by mixing the above-mentioned dispersant, thickener, and distilled water is, A method for manufacturing graphene ink characterized by mixing 1 to 5 parts by weight of the dispersant and 0.1 to 1 part by weight of the thickener with respect to 100 parts by weight of the mixture of the dispersant, the thickener, and distilled water.
5. In paragraph 1, A method for manufacturing graphene ink, characterized in that the dispersant is selected from the group consisting of polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinyl acetate (PVAc), and polyvinyl butyral (PVB), and the thickener is selected from the group consisting of carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), and guar gum.
6. In paragraph 1, The step of manufacturing graphene ink by mixing the above organic vehicle and the above graphene is, A method for manufacturing graphene ink, characterized by mixing 1 to 5 parts by weight of graphene with respect to 100 parts by weight of a mixture of the organic vehicle and the graphene.
7. Comprising graphene; a dispersant; a thickener; and distilled water; and A graphene ink composition characterized by comprising, for every 100 parts by weight of a mixture of the graphene, a dispersant, a thickener, and distilled water, 1 to 5 parts by weight of the graphene, 1 to 5 parts by weight of the dispersant, and 0.1 to 1 part by weight of the thickener.
8. In Paragraph 7, A graphene ink composition characterized by the above graphene being manufactured by applying thermal shock to expanded graphite.
9. In Paragraph 7, A graphene ink composition characterized in that the above-mentioned dispersant is any one selected from the group consisting of polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinyl acetate (PVAc), and polyvinyl butyral (PVB), and the above-mentioned thickener is any one selected from the group consisting of carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), and guar gum.
10. Graphene ink manufactured according to the manufacturing method of claim 1.

Description

Non-Oxidized-Reduced Graphene Ink Using Expanded Graphite and Manufacturing Method Thereof The present invention relates to graphene ink and a method for manufacturing the same. This project (result) is the result of the Phase 3 Leading University Industry-Academic Cooperation Project (LINC 3.0), which was funded by the Ministry of Education and the National Research Foundation of Korea. Graphene is a planar sheet-like material with an atomic-level thickness (~3 Å) that can have superior electrical and mechanical properties compared to other novel materials, such as electrical conductivity, flexibility, and mechanical/chemical stability. In particular, graphene can be applied in a wide range of fields, including chemical sensors, field-effect transistors, and organic optoelectronic devices. Recently, composite materials such as graphene, graphene/conductive polymer, graphene/metal oxide, graphene/carbon nanotube, and graphene/metal nanoparticle are being utilized as various electrode materials to improve the properties of supercapacitors, touchscreens, batteries, and transparent electrodes. Due to the unique chemical and physical properties of graphene (such as the tendency to clump together due to strong Van der Waals forces between graphene layers, non-polar properties, and low surface energy of graphene), it is difficult to exfoliate graphite into graphene (even if exfoliated, the yield of graphene is significantly low), and it is difficult to develop graphene ink manufacturing technology because it is not dispersed in most solvents. To overcome this, conventionally, graphene oxide was synthesized by oxidizing graphite with a strong oxidizing agent to exfoliate the graphene layer, and then mixed with an organic vehicle (a mixed solution of a solvent, an organic binder, and additives) to undergo a reduction process to produce reduced graphene oxide ink (commonly referred to as graphene). Even after undergoing a reduction process to improve the electrical conductivity of graphene oxide, which has extremely low electrical conductivity, the resulting electrical conductivity is significantly lower than that of graphene. Accordingly, there is a continuous demand for the development of graphene ink manufacturing methods to overcome the limitations of the aforementioned methods. Figure 1 shows the volume expansion results according to thermal shock conditions. Figure 2 shows the coating state immediately after coating and after drying according to graphene concentrations of (a) 0.5 wt%, (b) 1 wt%, (c) 2 wt%, and (d) 3 wt%. Figure 3 shows the partial discharge sensor before and after coating it with graphene ink. Figure 4 shows the results of measuring the sensor output according to the graphene coating. (a) Partial discharge occurrence (9.8 kV), (b) Comparison of sensor sensitivity. The terms used in this invention have been selected based on currently widely used general terms, taking into account their functions within the invention; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms have been arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this invention should be defined not merely by their names, but based on their meanings and the overall content of the invention. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application. When a part of a specification is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. The present invention will be described in detail below. The present invention provides a method for manufacturing graphene ink, characterized by comprising the steps of: placing expanded graphite into an alumina crucible and setting a temperature; after reaching the set temperature, placing the crucible containing the expanded graphite into an electric furnace and applying a thermal shock to exfoliate graphene from the expanded graphite; mixing a dispersant, a thickener, and distilled water to produce an organic vehicle; and mixing