CN111916694B - A kind of preparation method of graphene iron-based composite material - Google Patents

Abstract

The invention discloses a preparation method of a graphene iron-based composite material, which comprises the following steps: (1) cutting stainless steel into metal plates, and pretreating with corundum gauze; (2) cutting a ceramic wafer into required samples, and roughening the surface of the ceramic wafer by using abrasive paper; (3) placing stainless steel in an induction heating machine, placing a ceramic wafer on a steel sheet, scattering graphite powder on one surface of the polished ceramic wafer, and placing another ceramic wafer on the polished ceramic wafer; (4) heating the sample; (5) heating, putting the mixture and potassium ferrate into a polyurethane ball ink tank for wet ball milling; (6) putting the mixed powder subjected to ball milling into a vacuum drying oven for drying; (7) and performing dry ball milling on the dried mixed powder again to obtain the required sample. According to the invention, an induction thermal decomposition mode is added, and graphite is converted into single-layer or thin-layer graphene oxide in advance; the wet ball milling is firstly carried out, and then the dry ball milling is carried out, so as to achieve the purpose of connection.

Description

A kind of preparation method of graphene iron-based composite material

technical field

The invention relates to a preparation method of a graphene iron-based composite material, and belongs to the technical field of iron-based composite materials.

Background technique

At present, graphene-enhanced iron-based composite materials are getting more and more attention. First, graphene itself has good electrical conductivity, that is, it has good electron transport channels, and because graphene has good thermal conductivity, this guarantees The stability of the iron-based/graphene nanocomposite during use; second: graphene is a single-layer graphite with only one carbon atom, with a thickness of 0.335 nm, and the ultra-thin graphene sheet can act as a barrier to prevent nanoparticles The aggregation of lithium ion and increase the cycle performance of the battery; third: graphene itself is an active material for storing lithium ions, which is very beneficial to improve the reversible specific capacity of lithium ion batteries; fourth: iron-based nanoparticles are immobilized on the coiled graphene On the surface, the transport distance of lithium ions on iron-based nanoparticles is shortened, so that lithium-ion batteries have high rate performance. For the above reasons, graphene-reinforced iron-based composites have been increasingly used in the field of batteries. However, this technology also has obvious defects, that is, how to ensure the uniform adhesion of iron ions on the graphene surface and increase the dispersibility of the composite material.

Through existing technology and literature search, it is found that: Chinese patent CN106566942A discloses a preparation method of graphene reinforced aluminum matrix composite material, including preparing graphene oxide, surface modification of aluminum powder to prepare flake aluminum powder, preparation The steps of graphene/aluminum hydroxide/aluminum multilayer coating structure powder; the graphene and aluminum powder are mixed and then added to the alcohol solution, and then ultrasonically treated for 0.1-1 h at a temperature of 30-50 ° C to prepare Graphene/aluminum hydroxide/aluminum multi-layer coating structure powder; put the prepared graphene/aluminum hydroxide/aluminum multi-layer coating structure powder into a hot pressing sintering mold, and load the pressure of 100-200MPa , Argon or nitrogen protection, hot pressing sintering to obtain high-performance graphene-reinforced aluminum matrix composites.

Chinese patent 105355873A discloses an iron-based metal-organic framework compound, an iron-based metal-organic framework compound/graphene composite material formed with graphene, and its application as a negative electrode active material in lithium ion batteries. The iron-based metal-organic framework compound and the iron-based metal-organic framework compound/graphene composite material are used as negative electrode active materials for lithium ion batteries.

The above technologies are the preparation of graphene-enhanced aluminum-based composite materials and graphene-enhanced iron-based composite materials, both of which take into account the dispersibility of graphene and matrix powder materials, but the dispersion effect cannot be controlled, and the agglomeration of graphene cannot be controlled. At the same time, the above patents directly use graphene as a reinforcement, and the cost is relatively high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to obtain a graphene-reinforced iron-based composite material with good connectivity, and to provide a basis for its synthesis and preparation in batteries and other related fields.

The invention utilizes induction thermal decomposition of graphite and ball milling to improve the connectivity of iron in graphene oxide, and provides a suitable treatment method for related research and preparation technology based on iron-based graphene composite materials. The present invention must first ensure that in the process of induction heating, the graphite can achieve a good thermal decomposition effect, which is to ensure that in the process of heating, it can reach a sufficiently high temperature after conduction through the thin ceramic sheet; The connection between graphene oxide and iron-based materials in the process promotes the isotropy of the composite material; the third is to minimize the re-agglomeration of graphene during the drying process, and to use vacuum drying as much as possible; To ensure that the re-agglomerated graphene oxide can be connected during dry ball milling.

The invention provides a preparation method of a graphene iron-based composite material with high connectivity, good bonding and simple operation, comprising the following steps:

Step 1: Cut the 316L stainless steel into metal plates of 15mm×15mm×3mm, and use 600-1500 mesh corundum gauze to pretreat the 316L surface for 1.5-2.5h;

Step 2: Select a ceramic sheet with a thickness of 3-5mm, cut and grind the ceramic sheet into a 15×15mm sample, and make 2-5 samples of the same size ceramic sheet;

The third step: use 40-200 mesh sandpaper to grind one side of the two ceramic sheets for 1-3 hours to roughen the surface;

Step 4: Put the 316L stainless steel in the induction heating machine, place one of the ceramic sheets on the 316L steel sheet, with the unpolished side facing down, and add 1.2-1.5g of graphite powder on the ceramic sheet, and then put another The ceramic sheet is placed on the graphite powder with the unpolished side facing up;

Step 5: Select the heating current of the induction heating machine to be 260-290A, and the heating time to be 80-100s;

Step 6: Put the heated graphite and 7.5-8g of potassium ferrate into the polyurethane ball mill, choose the diameter of the zirconium balls as 3mm, 5mm and 7mm, add 25-30ml of deionized water, and choose the rotation speed as 330 -400r/min, the time of wet ball milling is 20-30h;

Step 7: Put the ball-milled mixed powder in a vacuum drying oven, the drying temperature is 80-140°C, and the drying time is 12-15h;

The eighth step: put the dried mixed powder in the polyurethane ball mill again, choose dry ball milling, the ball milling time is 350-400r/min, and the ball milling time is 40-48h, and finally the required sample is obtained.

In the present invention, the purpose of inductively heating graphite before ball milling is to use high temperature to thermally decompose the graphite, and transform from a multi-layered graphite structure to a single-layer or thin-layer graphene to obtain graphene oxide; The purpose of the stainless steel is to use an induction heating machine to heat the stainless steel, and the heat is conducted to the graphite through the ceramic sheet to achieve the purpose of thermal decomposition; the purpose of the wet ball milling in the present invention is that iron ions are better adsorbed on the sheet of graphene oxide. ; The subsequent dry ball milling is due to a small amount of graphene agglomeration during the drying process, and the purpose of using dry ball milling to increase connectivity.

Beneficial effects of the present invention:

(1) Compared with the general graphene-reinforced iron-based composite material that achieves the purpose of dispersion simply by ball milling, the method of induction thermal decomposition is added in the present invention to convert graphite to single-layer or thin-layer graphene oxide in advance.

(2) Compared with the traditional graphene-reinforced iron-based composite material, the present invention uses graphite as a raw material to form graphene oxide in a certain way, saving a certain amount of resource costs;

(3) In the present invention, wet ball milling is performed first, and then dry ball milling is performed. The purpose is to first achieve the purpose of separation and attachment, and then achieve the purpose of optimization through dry ball milling. Compared with the general single ball milling method, the effect is more ideal. , and finally achieve the purpose of linking;

(4) The present invention achieves the purpose of connecting the graphene-iron-based composite material through the method of ball milling, which is simpler compared with the general chemical method.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. The technical solutions of the present invention are described in detail below with reference to the embodiments, but the protection scope is not limited by this.

Example 1

First, cut 316L stainless steel into metal plates of 15mm×15mm×3mm, and use 600-1500 mesh corundum gauze to pretreat the surface of 316L for 1.5h; select a ceramic sheet with a thickness of 5mm, and cut and grind the ceramic sheet into 15× 15mm sample, three samples of the same size ceramic sheet were prepared; then one side of the two ceramic sheets was polished with 40-200 mesh sandpaper for 3 hours to roughen the surface; then 316L stainless steel was placed in induction heating In the machine, place one of the ceramic sheets on the 316L steel sheet, with the unpolished side facing down, and add 1.5g of graphite powder on the ceramic sheet, and then place another ceramic sheet on the graphite powder, with the unpolished side upward; choose the heating current of the induction heating machine to be 260A, and the heating time to be 90s; put the heated graphite and 7.6g of potassium ferrate into the polyurethane ball mill, and choose the diameter of the zirconium balls as 3mm, 5mm and 7mm. , and add 25ml of deionized water, select the rotating speed as 350r/min, and the wet ball milling time of 20h; put the mixed powder after ball milling in a vacuum drying oven, the drying temperature is 120 ℃, and the drying time is 13h; The resulting mixed powder was placed in a polyurethane ball milling tank again, and dry ball milling was selected. The ball milling time was 350 r/min and the ball milling time was 45 h. Finally, the desired sample was obtained.

Example 2

First, cut 316L stainless steel into metal plates of 15mm×15mm×3mm, and use 600-1500 mesh corundum gauze to pretreat the surface of 316L for 1.8h; select a ceramic sheet with a thickness of 4mm, and cut and grind the ceramic sheet into 15× 15mm sample, 5 samples of the same size ceramic sheet were made; then one side of the two ceramic sheets was polished with 40-200 mesh sandpaper for 1h to roughen the surface; then 316L stainless steel was placed in induction heating In the machine, place one of the ceramic sheets on the 316L steel sheet, with the unpolished side facing down, add 1.2g of graphite powder to the ceramic sheet, and then place another ceramic sheet on the graphite powder, with the unpolished side upward; choose the heating current of the induction heating machine to be 280A, and the heating time to be 100s; put the heated graphite and 7.8g of potassium ferrate into the polyurethane ball mill jar, and choose the diameter of the zirconium balls as 3mm, 5mm and 7mm. , and add 28ml of deionized water, select the rotating speed as 390r/min, and the wet ball milling time for 25h; put the mixed powder after ball milling in a vacuum drying box, the drying temperature is 130 ℃, and the drying time is 15h; The mixed powder was placed in a polyurethane ball mill again, and dry ball milling was selected. The ball milling time was 370 r/min and the ball milling time was 48 h. Finally, the desired sample was obtained.

Example 3

First, cut 316L stainless steel into metal plates of 15mm×15mm×3mm, and use 600-1500 mesh corundum gauze to pretreat the surface of 316L for 2.2h; select a ceramic sheet with a thickness of 3mm, and cut and grind the ceramic sheet into 15× 15mm sample, 4 samples of the same size ceramic sheet were made; then one side of the two ceramic sheets was polished with 40-200 mesh sandpaper for 2 hours to roughen the surface; then 316L stainless steel was placed in induction heating In the machine, place one of the ceramic sheets on the 316L steel sheet, with the unpolished side facing down, add 1.3g of graphite powder on the ceramic sheet, and then place another ceramic sheet on the graphite powder, with the unpolished side upward; choose the heating current of the induction heating machine to be 285A, and the heating time to be 80s; put the heated graphite and 7.9g of potassium ferrate into the polyurethane ball mill, and choose the diameter of the zirconium balls as 3mm, 5mm and 7mm. , and add 29ml of deionized water, select the speed of 340r/min, and the wet ball milling time of 26h; put the mixed powder after ball milling in a vacuum drying box, the drying temperature is 100 ℃, and the drying time is 14h; The mixed powder was placed in a polyurethane ball mill again, and dry ball milling was selected. The ball milling time was 380 r/min and the ball milling time was 43 h. Finally, the desired sample was obtained.

Claims (5)

1. a preparation method of graphene iron-based composite material, is characterized in that comprising the following steps: Step 1: Cut 316L stainless steel into metal plates of 15mm×15mm×3mm, and pretreat the surface of the metal plates with corundum gauze for 1.5-2.5h; Step 2: Select a ceramic sheet with a thickness of 3-5mm, cut and grind the ceramic sheet into a 15×15mm sample, and make 2-5 samples of the same size ceramic sheet; The third step: use 40-200 mesh sandpaper to grind one side of the two ceramic sheets for 1-3 hours to roughen the surface; Step 4: Place the 316L stainless steel in the induction heating machine, place one of the ceramic sheets on the 316L stainless steel sheet, with the unpolished side facing down, add graphite powder on the ceramic sheet, and place the other ceramic sheet on the graphite On powder, the unpolished side is facing up; The fifth step: heating the above sample with an induction heating machine; the heating current is 260-290A, and the heating time is 80-100s; Step 6: Put the heated graphite and potassium ferrate into the polyurethane ball mill jar, choose the diameter of the zirconium balls as 3mm, 5mm, 7mm, add deionized water, choose the rotation speed of 330-400r/min, wet ball mill The time is 20-30h; The seventh step: place the ball-milled mixed powder in a vacuum drying oven to dry; The eighth step: put the dried mixed powder in the polyurethane ball mill again, choose dry ball milling, the ball milling time is 350-400r/min, and the ball milling time is 40-48h, and finally the required sample is obtained. 2. the preparation method of graphene iron-based composite material according to claim 1, is characterized in that: described corundum gauze is 600-1500 mesh. 3. the preparation method of graphene iron-based composite material according to claim 1, is characterized in that: in the 4th step, the graphite powder added on the ceramic sheet is 1.2-1.5g. 4. the preparation method of graphene iron-based composite material according to claim 1, is characterized in that: the potassium ferrate added in the 6th step is 7.5-8g, and the consumption of deionized water is 25-30ml. 5. The preparation method of the graphene iron-based composite material according to claim 1, characterized in that: in the seventh step, the drying temperature is 80-140° C., and the drying time is 12-15 h.