Copper-plated graphene and preparation method thereof

Abstract

The invention provides copper-plated graphene and a preparation method thereof. The preparation method comprises the following steps: immersing graphene oxide into a colloidal copper activation solution, and carrying out first ultrasonic treatment to prepare copper-loaded graphene; immersing the copper-loaded graphene into a plating solution, and carrying out second ultrasonic treatment and copper plating to obtain pre-plated copper graphene; the pre-plated copper graphene is subjected to passivation treatment, and the copper-plated graphene is obtained; the colloid activated copper solution comprises gelatin and nano-copper particles. Colloidal copper activating liquid is used as a copper source, nano-copper particles which are stably dispersed are attached to the surface of graphene through first ultrasonic treatment, uniform growth of a copper layer on the surface of graphene is achieved under promotion of the ultrasonic cavitation effect of second ultrasonic treatment, and copper-plated graphene with a compact copper-plated layer is prepared through passivation treatment.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of nanocomposite material preparation, in particular to composite graphene preparation, and more particularly to copper-plated graphene and a preparation method thereof. BACKGROUND

[0002] It has been widely studied to use graphene as a reinforcing phase to improve the mechanical properties of alloy materials. By plating copper on the surface of graphene, on one hand, the agglomeration of graphene can be prevented, and the dispersibility of graphene in a metal matrix can be improved; on the other hand, the wettability of graphene and metal can be enhanced, and energy and electrons can be more effectively transferred between the two, so that the reinforcing effect of graphene can be fully played, and the material can be endowed with excellent properties of both graphene and copper, laying a foundation for the application of the material in a wider field. Traditional chemical copper plating requires palladium (Pd) activation, and palladium is high in cost and highly toxic. The post-processing adopts chromate passivation, and there is a risk of heavy metal pollution.

[0003] CN120138618A discloses a copper-containing plating solution and a method for plating copper on the surface of graphene. The application uses glyoxylic acid in the copper-containing plating solution to quickly provide electrons at the initial stage of the reaction, so that copper ions quickly nucleate. Hypophosphite can continuously reduce copper ions in the plating solution into copper atoms, realizing the continuous growth of the copper layer. Tetrasodium ethylenediaminetetraacetate can form a complex with copper ions, which has high stability and slowly releases copper ions. Sodium citrate as a secondary complexing agent can adjust the discharge potential, further optimizing the deposition process of copper ions, so as to realize the dense coating of the copper-plated substrate and effectively improve the copper plating effect.

[0004] CN120002000A discloses a preparation method of reduced graphene oxide powder modified by nano-copper, comprising the following steps: S1: uniformly mixing a reduced graphene oxide dispersion liquid and a copper chloride solution to obtain a mixed liquid A; S2: reducing the mixed liquid A by using a reducing agent to obtain a mixed liquid B; S3: adjusting the pH of the mixed liquid B to 8-9 to obtain a mixed liquid C; S4: titrating the mixed liquid C with an alkaline solution until the color is red, and then standing and filtering to obtain a precipitate D; S5: washing the precipitate D until the supernatant is neutral, and then drying to obtain a precipitate E; and S6: sintering the precipitate E in an inert atmosphere to obtain the reduced graphene oxide powder modified by nano-copper.

[0005] CN108677172A discloses a zero-emission and pollution-free graphene chemical copper plating method. 2+ +HCHO+3OH - →Cu↓+HCOO -+2H2O, realizing fast and efficient electroless copper plating of graphene. After graphene is electrolessly plated with copper, agglomeration of graphene is greatly reduced, the copper plating layer is uniform and dense, and is firmly combined with the substrate, effectively improving wettability of the interface between graphene and the copper substrate, enhancing the interface bonding between the graphene reinforcing phase and the copper substrate, and greatly improving the performance of the graphene reinforced copper matrix composite. Moreover, the graphene copper plating method can recycle the plating solution, without waste and pollutant emissions, and is eco-friendly and non-toxic.

[0006] Therefore, it is of great significance to provide a graphene copper plating process with good corrosion resistance and environmental protection. SUMMARY

[0007] In view of the deficiencies in the prior art, the purpose of the present application is to provide a graphene copper plating and a preparation method thereof. The present application uses a colloidal copper activating solution as a copper source, and through first ultrasonic treatment, stably dispersed nano copper particles are attached to the surface of graphene. Under the promotion of the ultrasonic cavitation effect of second ultrasonic treatment, uniform growth of a copper layer on the surface of graphene is realized. After passivation treatment, graphene copper plating with a dense copper plating layer is prepared.

[0008] To achieve the purpose of the present application, the following technical solutions are adopted:

[0009] In a first aspect, the present application provides a preparation method of graphene copper plating, which comprises:

[0010] The graphene oxide is immersed in a colloidal copper activating solution, and first ultrasonic treatment is performed to prepare graphene oxide loaded with copper particles. The graphene oxide loaded with copper particles is immersed in a plating solution, and second ultrasonic treatment is performed to carry out copper plating, thereby obtaining pre-plated copper graphene. The pre-plated copper graphene is subjected to passivation treatment to obtain the graphene copper plating. The colloidal activating copper solution comprises gelatin and nano copper particles.

[0011] The present application uses a colloidal copper activating solution as a copper source, without the need to use noble metals for activation. Through first ultrasonic treatment, stably dispersed nano copper particles are attached to the surface of graphene. Under the promotion of the ultrasonic cavitation effect of second ultrasonic treatment, uniform growth of a copper layer on the surface of graphene is realized. After passivation treatment, graphene copper plating with a dense copper plating layer is prepared.

[0012] Preferably, the frequency of the first ultrasonic treatment is 40 kHz to 60 kHz.

[0013] Preferably, the power of the first ultrasonic treatment is 100 W to 300 W.

[0014] Preferably, the time of the first ultrasonic treatment is 30 min to 60 min.

[0015] Preferably, the temperature of the second ultrasonic treatment is 40 DEG C to 50 DEG C.

[0016] Preferably, the frequency of the second ultrasonic treatment is 40 kHz to 60 kHz.

[0017] Preferably, the power of the second ultrasonic treatment is 100 W to 200 W.

[0018] Preferably, the time of the second ultrasonic treatment is 10 min to 200 min, preferably 15 min to 30 min.

[0019] Preferably, the mass ratio of the graphene oxide to the nano-copper particles in the colloidal copper activating solution is 1:(10 to 15).

[0020] Preferably, the average particle size of the nano-copper particles in the colloidal copper activating solution is 5 nm to 20 nm.

[0021] Preferably, the flake size of the graphene oxide is 10 μm to 30 μm.

[0022] Preferably, the mass fraction of oxygen in the graphene oxide is 2 wt% to 10 wt%.

[0023] In one preferred technical solution of the present application, the preparation method of the colloidal copper activating solution comprises:

[0024] dissolving a soluble copper salt in a gelatin solution to obtain a mixed solution; adding a reducing agent to the mixed solution to obtain a nano-copper colloidal solution through a reduction reaction; adjusting the pH to 8.5 to 9.5 to obtain the colloidal copper activating solution.

[0025] Preferably, the soluble copper salt comprises any one or a combination of at least two of copper sulfate, copper chloride, copper nitrate or copper acetate.

[0026] Preferably, the molar ratio of copper in the soluble copper salt to gelatin in the gelatin solution is 1:(0.8 to 2.0), preferably 1:(1.2 to 1.5).

[0027] Preferably, the reducing agent comprises potassium borohydride.

[0028] Preferably, the molar ratio of the reducing agent to copper in the soluble copper salt is (1 to 2):1.

[0029] Preferably, the concentration of the soluble copper salt in the mixed solution is 5 g / L to 15 g / L.

[0030] Preferably, the concentration of the gelatin solution is 1 g / L to 3 g / L.

[0031] Preferably, the amount of the reducing agent added to the mixed solution is 0.2 g / L to 0.5 g / L.

[0032] Preferably, the preparation method further includes adding an antifoaming agent to the colloidal copper activation solution, wherein the antifoaming agent includes n-octanol.

[0033] Preferably, the amount of defoamer added to the colloidal copper activation solution is 0.1 mL / L to 0.3 mL / L.

[0034] Preferably, the plating solution comprises 20 g / L to 50 g / L disodium ethylenediaminetetraacetate, 5 g / L to 15 g / L potassium sodium tartrate, 10 g / L to 30 g / L soluble copper salt, 0 to 20 g / L sodium hydroxide, 0 to 20 g / L potassium hydroxide, 5 mg / L to 20 mg / L 2,2'-bipyridine, 10 mg / L to 50 mg / L potassium ferricyanide, and 5 mg / L to 15 mg / L formaldehyde.

[0035] Preferably, the pH of the plating solution is 12.0 to 13.0.

[0036] Preferably, the molar ratio of 2,2'-bipyridine to potassium ferrocyanide in the plating solution is 1:(2-4).

[0037] Preferably, the passivation energy treatment includes immersing the pre-plated copper graphene in a passivation solution, wherein the passivation solution comprises a 3wt% to 5wt% boric acid solution.

[0038] Preferably, the passivation treatment time is 10 min to 30 min.

[0039] In a second aspect, the present invention provides a copper-plated graphene, which is prepared by the preparation method described in the first aspect.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] This invention uses colloidal copper activating solution as the copper source. After a first ultrasonic treatment, stable and dispersed nano-copper particles are attached to the graphene surface. Under the promotion of the ultrasonic cavitation effect of the second ultrasonic treatment, the copper layer grows uniformly on the graphene surface. After passivation treatment, copper-plated graphene with a dense copper layer is prepared. Attached Figure Description

[0042] Fig. 1 This shows the distribution of O elements on the surface of the copper-plated graphene prepared in Example 1.

[0043] Fig. 2 This shows the surface carbon distribution of the copper-plated graphene prepared in Example 1.

[0044] Fig. 3 This shows the surface Cu element distribution of the copper-plated graphene prepared in Example 1. DETAILED DESCRIPTION

[0045] The technical solutions of the present application are further illustrated below by means of specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the use of the terms "including," "comprising," "having" and variations thereof herein is intended to be broad and encompass the terms "consisting of" and "consisting essentially of" and variations thereof. The use of the term "about" in relation to a numerical value means that the value is approximately correct and can vary by up to 10% of the stated value.

[0047] In the description of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0048] In one specific embodiment, the present application provides a preparation method of copper-plated graphene, the preparation method comprising:

[0049] The graphene oxide is immersed in a colloidal copper activation solution, and a first ultrasonic treatment is performed to obtain graphene oxide loaded with copper particles; the graphene oxide loaded with copper particles is immersed in a plating solution, and a second ultrasonic treatment is performed to carry out copper plating, thereby obtaining pre-copper-plated graphene; the pre-copper-plated graphene is subjected to passivation treatment to obtain the copper-plated graphene; the colloidal copper activation solution comprises gelatin and nano copper particles.

[0050] The present application uses colloidal copper activation solution as the copper source, and through the first ultrasonic treatment, the stably dispersed nano copper particles are attached to the surface of graphene, and under the promotion of the cavitation effect of the ultrasonic wave in the second ultrasonic treatment, the uniform growth of the copper layer on the surface of graphene is realized, and through passivation treatment, copper-plated graphene with a dense copper plating layer is prepared.

[0051] In some embodiments, the frequency of the first ultrasonic treatment is 40 kHz to 60 kHz, for example, it can be 40 kHz, 45 kHz, 50 kHz, 55 kHz or 60 kHz, including but not limited to the listed values, and other values not listed within the value range are also applicable.

[0052] In some embodiments, the power of the first ultrasonic treatment is 100 W to 300 W, for example, it can be 100 W, 150 W, 200 W, 250 W or 300 W, including but not limited to the listed values, and other values not listed within the value range are also applicable.

[0053] In some embodiments, the duration of the first ultrasonic treatment is 30 min to 60 min, for example, it can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0054] In some embodiments, the temperature of the second ultrasonic treatment is 40°C to 50°C, for example, 40°C, 42°C, 44°C, 46°C, 48°C, or 50°C, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable. This invention utilizes ultrasonic assistance and the ultrasonic cavitation effect to promote mass transfer in the plating solution, achieving uniform copper layer growth even at temperatures below 50°C.

[0055] In some embodiments, the frequency of the second ultrasonic treatment is 40kHz to 60kHz, for example, it can be 40kHz, 45kHz, 50kHz, 55kHz or 60kHz, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0056] In some embodiments, the power of the second ultrasonic treatment is 100W to 200W, for example, it can be 100W, 120W, 140W, 160W, 180W or 200W, including but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0057] In this invention, the power of the second ultrasonic treatment is selected based on the effective area of ​​the ultrasonic equipment used, and preferably the power density is 2W / cm². 2 ~4.2W / cm 2 For example, it could be 2W / cm 2 2.25W / cm 2 2.5W / cm 2 2.75W / cm 2 3W / cm 2 3.25W / cm 2 3.5W / cm 2 3.75W / cm 2 4W / cm 2 Or 4.2W / cm 2 This includes, but is not limited to, the listed values; other unlisted values ​​within the range also apply.

[0058] In some embodiments, the second ultrasonic treatment is performed for 10-200 minutes, for example, 10 minutes, 50 minutes, 100 minutes, 150 minutes or 200 minutes, including but not limited to the listed values, and other values not listed in the range are also applicable, preferably 15-30 minutes.

[0059] In some embodiments, the mass ratio of graphene oxide to nano-copper particles in the colloidal copper activating solution is 1:(10-15), for example, 1:10, 1:11, 1:12, 1:13, 1:14 or 1:15, including but not limited to the listed values, and other values not listed in the range are also applicable.

[0060] In some embodiments, the average particle size of the nano-copper particles in the colloidal copper activating solution is 5-20 nm, for example, 5 nm, 7.5 nm, 10 nm, 12.5 nm, 15 nm, 17.5 nm or 20 nm, including but not limited to the listed values, and other values not listed in the range are also applicable.

[0061] In some embodiments, the flake size of the graphene oxide is 10-30 μm, for example, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm, including but not limited to the listed values, and other values not listed in the range are also applicable.

[0062] In some embodiments, the mass fraction of oxygen in the graphene oxide is 2wt%-10wt%, for example, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, including but not limited to the listed values, and other values not listed in the range are also applicable.

[0063] In some embodiments, the preparation method of the colloidal copper activating solution comprises:

[0064] dissolving a soluble copper salt in a gelatin solution to obtain a mixed solution; adding a reducing agent to the mixed solution to obtain a nano-copper colloidal solution by reduction reaction; adjusting the pH to 8.5-9.5, for example, the pH can be 8.5, 8.7, 8.9, 9.1, 9.3 or 9.5, to obtain the colloidal copper activating solution.

[0065] In the present application, the gelatin solution with a pH of 8.5-9.5 is used as a stable medium to prepare the colloidal copper activating solution, and the gelatin stabilizes the nano-copper particles, replacing the traditional palladium activator, reducing the cost and avoiding toxicity.

[0066] In some embodiments, the soluble copper salt comprises any one or a combination of copper sulfate, copper chloride, copper nitrate or copper acetate.

[0067] In some embodiments, the molar ratio of copper in the soluble copper salt to gelatin in the gelatin solution is 1:(0.8-2.0), for example, it can be 1:0.8, 1:1, 1:1.2, 1:1.25, 1:1.3, 1:1.35, 1:1.4, 1:1.45, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.0, including but not limited to the listed values, other values not listed in the value range are also applicable, and preferably 1:(1.2-1.5). In the present application, the molar mass of gelatin is calculated according to the molecular formula C6H 12 O6, and the molar mass is 180 g / mol.

[0068] In some embodiments, the reducing agent comprises potassium borohydride.

[0069] In the present application, potassium borohydride is selected as the reducing agent, and its strong reducing property can obtain smaller nano-copper particles, thereby improving the compactness of the copper plating layer.

[0070] In some embodiments, the molar ratio of the reducing agent to copper in the soluble copper salt is (1-2):1, for example, it can be 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1 or 2:1, including but not limited to the listed values, other values not listed in the value range are also applicable.

[0071] In some embodiments, the concentration of the soluble copper salt in the mixed solution is 5 g / L-15 g / L, for example, it can be 5 g / L, 7.5 g / L, 10 g / L, 12.5 g / L or 15 g / L, including but not limited to the listed values, other values not listed in the value range are also applicable.

[0072] In some embodiments, the concentration of the gelatin solution is 1 g / L-3 g / L, for example, it can be 1 g / L, 1.5 g / L, 2 g / L, 2.5 g / L or 3 g / L, including but not limited to the listed values, other values not listed in the value range are also applicable.

[0073] In some embodiments, the amount of reducing agent added to the mixed solution is 0.2 g / L-0.5 g / L, for example, it can be 0.2 g / L, 0.25 g / L, 0.3 g / L, 0.35 g / L, 0.4 g / L, 0.45 g / L or 0.5 g / L, including but not limited to the listed values, other values not listed in the value range are also applicable.

[0074] In some embodiments, the preparation method further comprises adding an antifoaming agent to the colloidal copper activating solution, the antifoaming agent comprising n-octanol.

[0075] In some embodiments, the amount of the antifoaming agent added to the colloidal copper activating solution is 0.1 mL / L to 0.3 mL / L, for example, it can be 0.1 mL / L, 0.15 mL / L, 0.2 mL / L, 0.25 mL / L or 0.3 mL / L, including but not limited to the listed values, other values not listed in the value range are also applicable.

[0076] In some embodiments, the plating solution comprises 20 g / L to 50 g / L disodium ethylenediaminetetraacetate, for example, it can be 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L or 50 g / L, 5 g / L to 15 g / L potassium sodium tartrate, for example, it can be 5 g / L, 7.5 g / L, 10 g / L, 12.5 g / L or 15 g / L, 10 g / L to 30 g / L soluble copper salt, for example, it can be 10 g / L, 15 g / L, 20 g / L, 25 g / L or 30 g / L, 0 to 20 g / L sodium hydroxide, for example, it can be 0, 5 g / L, 10 g / L, 15 g / L or 20 g / L, 0 to 20 g / L potassium hydroxide, for example, it can be 0, 5 g / L, 10 g / L, 15 g / L or 20 g / L, 5 mg / L to 20 mg / L 2,2'-bipyridine, for example, it can be 50 mg / L, 75 mg / L, 100 mg / L, 150 mg / L or 200 mg / L, 10 mg / L to 50 mg / L potassium ferricyanide, for example, it can be 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L or 50 mg / L, and 5 mg / L to 15 mg / L formaldehyde, for example, it can be 5 mg / L, 7.5 mg / L, 10 mg / L, 12.5 mg / L or 15 mg / L.

[0077] In some embodiments, to ensure uniformity of the plating solution components, disodium ethylenediaminetetraacetate, potassium sodium tartrate, soluble copper salt, sodium hydroxide and / or potassium hydroxide are sequentially dissolved in water, then 2,2'-bipyridine and potassium ferricyanide are added, and finally formaldehyde is slowly added, stirred, and the pH of the plating solution is adjusted to 12.0-13.0.

[0078] In some embodiments, the pH of the plating solution is 12.0 to 13.0, for example, the pH can be 12.0, 12.2, 12.4, 12.6, 12.8 or 13.0, including but not limited to the listed values, other values not listed in the value range are also applicable.

[0079] In some embodiments, the molar ratio of 2,2'-bipyridine to potassium ferrocyanide in the plating solution is 1:(2-4), for example, it can be 1:2, 1:2.25, 1:2.5, 1:2.75, 1:3, 1:3.25, 1:3.5, 1:3.75 or 1:4, including but not limited to the listed values, and other values not listed in the value range are also applicable.

[0080] In the present application, 2,2'-bipyridine can be adsorbed on the active sites of copper crystal surface to inhibit the generation of dendrites, and potassium ferrocyanide can form [Fe(CN)6] 4+ Consumption of Cu in the plating solution + The two work together to play a key role in the performance of the copper-plated graphene. If the molar ratio of the two is unbalanced, for example, when 2,2'-bipyridine is excessive, the copper coating surface has fewer dendrites and is smooth due to excessive inhibition of copper deposition, but it will increase the brittleness of the copper coating; and excessive K4Fe(CN)6 will lead to a decrease in the stability of the plating solution, and brown Cu2[Fe(CN)6] precipitates will appear, thereby affecting the performance of the coating.

[0081] In some embodiments, the passivation treatment includes immersing the pre-copper-plated graphene in a passivation solution, and the passivation solution includes 3wt%-5wt% boric acid solution, for example, it can be 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%, including but not limited to the listed values, and other values not listed in the value range are also applicable.

[0082] In the present application, boric acid solution is used as a passivation agent instead of chromate passivation agent, which eliminates heavy metal pollution, and the density of the passivation layer is increased by 20%.

[0083] In some embodiments, the passivation treatment time is 10min-30min, for example, it can be 10min, 15min, 20min, 25min or 30min, including but not limited to the listed values, and other values not listed in the value range are also applicable.

[0084] In another specific embodiment, the present application provides a copper-plated graphene prepared by the preparation method described in the foregoing specific embodiment.

[0085] Example 1

[0086] The present embodiment provides a preparation method of copper-plated graphene, which comprises:

[0087] (1) Preparation of colloidal copper activation solution: according to the molar ratio of copper to gelatin in the gelatin solution being 1: (1.2-1.5), CuSO4·5H2O is dissolved in the gelatin solution to obtain a mixed solution of 1 g / L gelatin and 10 g / L CuSO4·5H2O; 0.3 g / L of potassium borohydride is added to the mixed solution, stirred, then 0.3 mL / L of n-octanol is added to defoam, and the pH is adjusted to 9.0 to obtain the colloidal copper activation solution, in which the average particle size of colloidal copper is 10 nm.

[0088] (2) Preparation of plating solution: 30 g / L of disodium ethylenediaminetetraacetate, 10 g / L of potassium sodium tartrate, 20 g / L of CuSO4·5H2O, 15 g / L of sodium hydroxide are sequentially dissolved in water, then 10 mg / L of 2,2'-dipyridyl and 30 mg / L of potassium ferricyanide are added, and finally 10 mg / L of formaldehyde is slowly added, stirred for 30 min, and the pH of the plating solution is adjusted to 12.5.

[0089] (3) Preparation of copper-plated graphene: according to the mass ratio of graphene oxide to copper in the colloidal copper activation solution being 1:13.5, graphene oxide with a flake size of 20 μm is immersed in the colloidal copper activation solution prepared in step (1), and subjected to first ultrasonic treatment at a frequency of 50 kHz, a power of 200 W, and a time of 45 min to prepare copper-loaded graphene; the copper-loaded graphene is immersed in the plating solution prepared in step (2), and subjected to second ultrasonic treatment at a frequency of 50 kHz, a power of 150 W, a power density of 3.14 W / cm2, and a time of 60 min at 45°C to complete copper plating, thereby obtaining pre-copper-plated graphene; the pre-copper-plated graphene is immersed in a 4 wt% boric acid solution, passivated for 20 min, and vacuum dried at 70°C for 12 h to obtain the copper-plated graphene. 2 , time for 60 min at 45°C to complete copper plating, thereby obtaining pre-copper-plated graphene; the pre-copper-plated graphene is immersed in a 4 wt% boric acid solution, passivated for 20 min, and vacuum dried at 70°C for 12 h to obtain the copper-plated graphene.

[0090] Example 2

[0091] The present embodiment provides a method for preparing copper-plated graphene, which comprises:

[0092] (1) According to the molar ratio of copper to gelatin in the gelatin solution being 1: (1.2-1.5), CuSO4·5H2O is dissolved in the gelatin solution to obtain a mixed solution of 1.5 g / L gelatin and 8 g / L CuSO4·5H2O; 0.2 g / L of potassium borohydride is added to the mixed solution, stirred, then 0.1 mL / L of n-octanol is added to defoam, and the pH is adjusted to 8.5 to obtain the colloidal copper activation solution, in which the average particle size of colloidal copper is 5 nm.

[0093] (2) Preparation of plating solution: 20 g / L of disodium ethylenediaminetetraacetate, 5 g / L of potassium sodium tartrate, 10 g / L of copper sulfate pentahydrate, and 5 g / L of sodium hydroxide were sequentially dissolved in water, then 5 mg / L of 2,2'-dipyridyl and 10 mg / L of potassium ferricyanide were added, and finally 5 mg / L of formaldehyde was slowly added, stirred for 20 min, and the pH of the plating solution was adjusted to 12.0.

[0094] (3) Preparation of copper-plated graphene: graphene oxide with a flake size of 10 μm was immersed in the colloidal copper activation solution prepared in step (1), and first ultrasonic treatment was performed at a frequency of 40 kHz and a power of 100 W for 30 min to prepare copper-loaded graphene; the copper-loaded graphene was immersed in the plating solution prepared in step (2), and second ultrasonic treatment was performed at a frequency of 40 kHz, a power of 100 W, a power density of 2.1 W / cm2, and a time of 10 min at 40°C to complete copper plating, thereby obtaining pre-copper-plated graphene; the pre-copper-plated graphene was immersed in a 3 wt% boric acid solution, passivated for 10 min, and vacuum dried at 75°C for 12 h to obtain the copper-plated graphene. 2

[0095] Example 3

[0096] The present embodiment provides a method for preparing copper-plated graphene, which comprises:

[0097] (1) Preparation of colloidal copper activation solution: CuSO4·5H2O was dissolved in a gelatin solution according to a molar ratio of copper to gelatin in the gelatin solution of 1:(1.2-1.5) to obtain a mixed solution of 3 g / L of gelatin and 15 g / L of CuSO4·5H2O; potassium borohydride was added to the mixed solution at 0.5 g / L, stirred, then n-octanol was added for defoaming at 0.3 mL / L, and the pH was adjusted to 9.5 to obtain the colloidal copper activation solution, in which the average particle size of colloidal copper was 20 nm.

[0098] (2) Preparation of plating solution: 50 g / L of disodium ethylenediaminetetraacetate, 15 g / L of potassium sodium tartrate, 30 g / L of copper sulfate pentahydrate, and 20 g / L of sodium hydroxide were sequentially dissolved in water, then 20 mg / L of 2,2'-dipyridyl and 50 mg / L of potassium ferricyanide were added, and finally 15 mg / L of formaldehyde was slowly added, stirred for 40 min, and the pH of the plating solution was adjusted to 13.0.

[0099] ​(3) Preparation of copper-plated graphene: Graphene oxide sheets with a diameter of 30 μm were immersed in the colloidal copper activation solution prepared in step (1) at a mass ratio of 1:15 to copper in the colloidal copper activation solution. The sheets were then subjected to a first ultrasonic treatment at a frequency of 60 kHz, a power of 300 W, and a time of 60 min to prepare copper-loaded graphene. The copper-loaded graphene was then immersed in the plating solution prepared in step (2) and subjected to an ultrasonic treatment at 50 °C at a frequency of 60 kHz, a power of 200 W, and a power density of 4.2 W / cm². 2 The copper plating process is completed by a second ultrasonic treatment lasting 200 minutes, resulting in pre-copper-plated graphene. The pre-copper-plated graphene is then immersed in a 5 wt% boric acid solution for passivation for 30 minutes, followed by vacuum drying at 70°C for 12 hours to obtain the copper-plated graphene.

[0100] Example 4

[0101] This embodiment provides a method for preparing copper-plated graphene. The preparation method is the same as in Example 1, except that 4 wt% Na2CrO4 solution is used instead of 4 wt% boric acid solution.

[0102] Example 5

[0103] This embodiment provides a method for preparing copper-plated graphene. The preparation method is the same as in Example 1, except that an equal mass of hydrazine hydrate is used instead of potassium borohydride.

[0104] Example 6

[0105] This embodiment provides a method for preparing copper-plated graphene. Except for the frequency of the first ultrasonic treatment in step (1) being 35 kHz, the preparation method is the same as in Example 1.

[0106] Example 7

[0107] This embodiment provides a method for preparing copper-plated graphene. Except for the frequency of the first ultrasonic treatment in step (1) being 65 kHz, the preparation method is the same as in Example 1.

[0108] Example 8

[0109] This embodiment provides a method for preparing copper-plated graphene. Except for the frequency of the second ultrasonic treatment in step (3) being 35 kHz, the preparation method is the same as in Example 1.

[0110] Example 9

[0111] This embodiment provides a method for preparing copper-plated graphene. Except for the frequency of the second ultrasonic treatment in step (3) being 65 kHz, the preparation method is the same as that in Example 1.

[0112] Example 10

[0113] The present example provides a preparation method of copper-plated graphene, which is the same as that of Example 1 except that the temperature of the second ultrasonic treatment in step (3) is 35℃.

[0114] Example 11

[0115] The present example provides a preparation method of copper-plated graphene, which is the same as that of Example 1 except that the temperature of the second ultrasonic treatment in step (3) is 55℃.

[0116] Comparative Example 1

[0117] The present comparative example provides a preparation method of copper-plated graphene, which is the same as that of Example 1 except that the first ultrasonic treatment is not performed.

[0118] Comparative Example 2

[0119] The present comparative example provides a preparation method of copper-plated graphene, which is the same as that of Example 1 except that the second ultrasonic treatment is not performed.

[0120] Comparative Example 3

[0121] The present comparative example provides a preparation method of copper-plated graphene, which is the same as that of Example 1 except that the passivation treatment is not performed.

[0122] Comparative Example 4

[0123] The present comparative example provides a preparation method of copper-plated graphene, which is the same as that of Example 1 except that the colloidal copper activation solution is replaced by a 0.1 MPdCl2solution.

[0124] Performance test:

[0125] The copper-plated graphene prepared in Example 1 was subjected to EDS test to test the distribution of O, C and Cu elements on the surface, and the test results are shown in Figs. 1 to 3 .

[0126] The conductivity of the copper-plated graphene prepared in all the above examples and comparative examples, the interfacial bonding strength between the copper-plated layer and the graphene oxide, the dispersion uniformity of the graphene, and the salt spray corrosion resistance of the copper-plated layer were tested, and the test results are shown in Table 1.

[0127] Among them, the test method of the conductivity is: using a direct current resistance tester to measure the volume resistivity (unit: Ω·m) of the copper-plated graphene.

[0128] The interfacial bonding strength was determined by nanoindentation (ISO 14577-1): Berkovich indenter, maximum load 10 mN, loading rate 0.5 mN / s; 10 test points were taken at the cross-sectional interface, and the average value was taken after removing the maximum and minimum values.

[0129] The dispersion uniformity of graphene was tested by TEM on the interlayer spacing.

[0130] The salt spray corrosion resistance was tested according to ASTM B117-19 "Standard Practice for Operating Salt Spray (Fog) Apparatus".

[0131] Table 1

[0132]

[0133] According to the test results in Table 1, the present application uses a colloidal copper activation solution as a copper source, and after the first ultrasonic treatment, the stably dispersed nano-copper particles adhere to the surface of graphene, and under the promotion of the ultrasonic cavitation effect of the second ultrasonic treatment, the uniform growth of the copper layer on the surface of graphene is realized, and after passivation treatment, copper-plated graphene with a dense copper layer is prepared.

[0134] According to the test results of Example 1 and Comparative Example 4, the present application uses gelatin as a stabilizing medium to prepare a colloidal copper activation solution, which stabilizes nano-copper particles by gelatin, replacing traditional palladium activators, significantly reducing costs and avoiding toxicity, and the prepared copper-plated graphene has excellent performance.

[0135] According to the test results of Example 1 and Example 4, the present application uses a boric acid solution as a passivation agent to replace a chromate passivation agent, eliminating heavy metal pollution, and the comprehensive improvement rate of the passivation layer density is 57.7%.

[0136] According to the test results of Example 1 and Example 5, the present application selects potassium borohydride as a reducing agent to utilize its strong reducing property to quickly reduce copper ions to obtain small-particle-size nano-copper particles, and a dense copper plating layer is prepared on the surface of graphene. If hydrazine hydrate with weaker reducing property is used to replace potassium borohydride with the same mass, it cannot form nano-sized colloidal copper, resulting in an unsatisfactory density of the copper plating layer and poor corrosion resistance.

[0137] According to the test results of Example 1 and Example 6, Example 7, and Comparative Example 1, if the first ultrasonic treatment is not performed, or the frequency of the first ultrasonic treatment is too large or too small, the stably dispersed nano-copper particles cannot adhere to the surface of graphene, resulting in poor performance of the copper-plated graphene.

[0138] According to the test results of Example 1 and Example 8 and Example 9 and Comparative Example 1, if the second ultrasonic treatment is not performed, or the frequency of the second ultrasonic treatment is too large or too small, the uniform growth of the copper layer on the surface of graphene cannot be achieved, resulting in poor performance of the copper-plated graphene.

[0139] According to the test results of Example 1 and Example 10 and Example 11, by the cooperation of the first ultrasonic treatment and the second ultrasonic treatment, the uniform growth of the copper layer on the surface of graphene is achieved at a lower temperature. If the temperature of the second ultrasonic treatment is too high during the copper plating process, thermal disturbance will be generated to damage the gelatin protective layer, causing copper particles to agglomerate and copper grains to abnormally grow. If the temperature of the second ultrasonic treatment is too low, the diffusion energy barrier of copper ions will increase, the deposition rate will decrease, the plating layer will be discontinuous, the porosity will increase, and the interface bonding force will weaken, which is not conducive to the uniform growth of the copper plating layer.

[0140] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing copper-plated graphene, characterized in that, The preparation method includes: Graphene oxide is immersed in colloidal copper activation solution and subjected to a first ultrasonic treatment to prepare graphene oxide loaded with copper particles; the graphene oxide loaded with copper particles is immersed in plating solution and subjected to a second ultrasonic treatment to perform copper plating to obtain pre-copper-plated graphene; the pre-copper-plated graphene is passivated to obtain copper-plated graphene. The colloidal activated copper solution includes gelatin and nano-copper particles.

2. The preparation method according to claim 1, characterized in that, The frequency of the first ultrasonic treatment is 40kHz to 60kHz; And / or, the power of the first ultrasonic treatment is 100W to 300W; And / or, the duration of the first ultrasonic treatment is 30 min to 60 min.

3. The preparation method according to claim 1, characterized in that, The temperature for the second ultrasonic treatment is 40℃~50℃; And / or, the frequency of the second ultrasonic treatment is 40kHz to 60kHz; And / or, the power of the second ultrasonic treatment is 100W to 200W; And / or, the duration of the second ultrasonic treatment is 10 min to 200 min.

4. The preparation method according to claim 1, characterized in that, The mass ratio of the graphene oxide to the colloidal copper activation solution in the nano-copper particles is 1:(10-15). And / or, in the colloidal copper activation solution, the average particle size of the nano-copper particles is 5nm to 20nm; And / or, the graphene oxide sheet diameter is 10 μm to 30 μm. And / or, the mass fraction of oxygen in the graphene oxide is 2 wt% to 10 wt%.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The preparation method of the colloidal copper activation solution includes: A soluble copper salt is dissolved in a gelatin solution to obtain a mixed solution; a reducing agent is added to the mixed solution to induce a reduction reaction, thereby obtaining a nano-copper colloidal solution; the pH is adjusted to 8.5–9.5 to obtain the colloidal copper activated solution.

6. The preparation method according to claim 5, characterized in that, The molar ratio of copper in the soluble copper salt to gelatin in the gelatin solution is 1:(0.8~2.0); And / or, the reducing agent includes potassium borohydride.

7. The preparation method according to claim 5 or 6, characterized in that, The preparation method further includes adding an antifoaming agent to the colloidal copper activation solution, wherein the antifoaming agent includes n-octanol.

8. The preparation method according to any one of claims 1 to 7, characterized in that, The plating solution contains 20 g / L to 50 g / L disodium ethylenediaminetetraacetate, 5 g / L to 15 g / L potassium sodium tartrate, 10 g / L to 30 g / L soluble copper salt, 0 to 20 g / L sodium hydroxide, 0 to 20 g / L potassium hydroxide, 5 mg / L to 20 mg / L 2,2'-bipyridine, 10 mg / L to 50 mg / L potassium ferricyanide, and 5 mg / L to 15 mg / L formaldehyde; And / or, the pH of the plating solution is 12.0 to 13.

0.

9. The preparation method according to any one of claims 1 to 8, characterized in that, The passivation energy treatment includes immersing the pre-plated copper graphene in a passivation solution, the passivation solution comprising a 3wt% to 5wt% boric acid solution; And / or, the passivation treatment time is 10 min to 30 min.

10. A copper-plated graphene, characterized in that, The copper-plated graphene is prepared by the preparation method according to any one of claims 1 to 9.

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