Method for decorating reduced graphene oxide nano composite material with copper particles for supercapacitor

Abstract

The invention relates to a synthesis method of a reduced graphene oxide nano composite material (Cu-rGO) decorated by copper particles, which is simple, convenient and efficient and can be realized at room temperature through an ethylene glycol (EG) reduction method. The preparation method comprises the following steps: firstly, synthesizing graphene oxide (GO) from a graphite sheet by adopting a Hummer method, and anchoring highly dispersed nano-copper particles on the reduced graphene oxide (rGO) sheet by adopting an ethylene glycol (EG) reduction method to form the reduced graphene oxide nanocomposite (Cu-rGO) decorated by the copper particles. The nano composite material has excellent electrochemical performance and is suitable for being used as a supercapacitor electrode material.

Description

Technical Field

[0001] The invention relates to a method for synthesizing a nanocomposite material, and in particular to the synthesis and characterization of a copper particle decorated reduced graphene oxide (Cu-rGO) nanocomposite material for supercapacitor electrodes. Background Art

[0002] With the continuous growth of energy demand and the gradual depletion of traditional energy, the development of efficient and environmentally friendly new energy storage devices has become a hot topic in global research. Supercapacitors have attracted much attention due to their high power density, long cycle life and fast charging and discharging capabilities. However, improving the energy density of supercapacitors is still the focus and difficulty of current research. As a two-dimensional nanomaterial, graphene shows great potential in the field of energy storage due to its unique physical and chemical properties. In particular, by introducing metal nanoparticles to decorate graphene, its electrochemical properties can be further improved, providing new ideas for the development of supercapacitors. Summary of the invention

[0003] The present invention provides a method for synthesizing a copper particle decorated reduced graphene oxide nanocomposite material (Cu-rGO), which is simple and efficient and can be achieved by an ethylene glycol (EG) reduction method at room temperature. First, graphene oxide (GO) is synthesized from graphite sheets by the Hummer method, and then highly dispersed nano-copper particles are anchored on reduced graphene oxide (rGO) sheets by an ethylene glycol (EG) reduction method to form a copper particle decorated reduced graphene oxide nanocomposite material (Cu-rGO). The nanocomposite material has excellent electrochemical properties and is suitable for supercapacitor electrode materials.

[0004] The present invention provides a method for synthesizing a copper particle decorated reduced graphene oxide nanocomposite material for a supercapacitor, the method comprising the following steps: a) Synthesis of graphene oxide (GO) from graphite flakes using a modified Hummer method; b) Highly dispersed nano-copper particles were anchored on reduced graphene oxide (rGO) sheets via ethylene glycol (EG) reduction method to form copper particle-decorated reduced graphene oxide nanocomposites (Cu-rGO).

[0005] As a further improvement of the above technical solution, the improved Hummer method includes adding a concentrated H2SO4 / H3PO4 mixture to a graphite sheet, and then adding high manganese potassium (KMnO4) to synthesize graphene oxide (GO).

[0006] As a further improvement of the above technical solution, the ethylene glycol (EG) reduction method further includes dispersing CuCl2 and PVP in an ethylene glycol solution, and then dispersing GO in the ethylene glycol solution, mixing and reflowing at a specific temperature to anchor the nano-copper particles on the rGO sheet.

[0007] The invention provides a copper particle decorated reduced graphene oxide nanocomposite material, which is synthesized by any of the above methods. The composite material has uniformly distributed copper nanoparticles with an average diameter between 8 and 9 nm.

[0008] As a further improvement of the above technical solution, the copper nanoparticles are completely fixed on the reduced graphene oxide sheets.

[0009] The present invention provides a method for using the copper particle decorated reduced graphene oxide nanocomposite material described in the above technical solution as a supercapacitor electrode material, which comprises integrating the nanocomposite material into the electrode of the supercapacitor.

[0010] The present invention also provides a supercapacitor, wherein the supercapacitor comprises at least one electrode, and the electrode is composed of the reduced graphene oxide nanocomposite material decorated with copper particles as described in the above technical solution.

[0011] The present invention also provides a device for preparing the copper particle decorated reduced graphene oxide nanocomposite material as claimed in the above claims, the device comprising a chemical reactor for performing an improved Hummer method, a reflux device for performing an ethylene glycol (EG) reduction method, and filtering and drying equipment for post-processing and drying the obtained nanocomposite material.

[0012] As a further improvement of the above technical solution, the chemical reactor is equipped with a temperature control system to accurately control the reaction temperature of synthesizing graphene oxide (GO), a reflux device for maintaining the ethylene glycol (EG) reduction reaction, and a filtering and drying device for separating the nanocomposite material from the reaction mixture and drying it to a desired moisture content. DETAILED DESCRIPTION

[0013] The technical solution of the present invention is described in more detail below, but the embodiments of the present invention are only for illustrative purposes and are not intended to limit the scope of the present invention. Those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the present invention. Example

[0014] Mix the graphite sheet with the concentrated H2SO4 / H3PO4 mixture and stir thoroughly. Add appropriate amount of KMnO4 to the mixture under freezing conditions, heat to 40-45°C and keep warm for 10-15 hours, cool to room temperature and pour in sufficient distilled water to carry out the oxidation process.

[0015] When the reaction is terminated, a small amount of H2O2 is added to the mixture, and then the mixture is filtered and washed with pure water and dilute HCl several times in succession. The resulting mixture is dried in vacuum at room temperature to obtain graphene oxide (GO).

[0016] Equal amounts of CuCl2 and PVP are fully dispersed in an ethylene glycol solution, and GO is fully dispersed in an ethylene glycol solution, and then the mixture is placed in a container. The resulting suspension is refluxed at about 130°C, then filtered, washed with acetone, and vacuum dried to obtain a copper particle-decorated reduced graphene oxide (Cu-rGO) nanocomposite material.

[0017] Product testing: X-ray diffractometer measurements were performed to determine the crystal phase and structure of the samples. The results showed that the Cu-rGO nanocomposite exhibited a peak at 2θ = 23.380, indicating that the Cu particles were successfully fixed on the rGO sheets.

[0018] The wavelengths of graphite, GO, rGO and Cu / rGO were recorded on a Nicolet spectrometer in the range of 500–4000 cm -1 The results showed that the spectrum of rGO showed a significant reduction in the stretching of OH groups compared with GO, indicating that GO had been effectively converted into rGO.

[0019] Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the morphology of the nanocomposites and the distribution of copper nanoparticles on the reduced graphene oxide sheets. The copper nanoparticles were uniformly distributed on the rGO nanosheets with an average diameter of 8-9 nm.

[0020] Cyclic voltammetry (CV) and constant current charge-discharge tests were carried out on an electrochemical workstation using a three-electrode system, using Cu-rGO as the working electrode, a standard saturated calomel electrode (SCE) as the reference electrode, a platinum wire as the counter electrode, and a 1 M sulfuric acid solution as the electrolyte.

[0021] At different scan rates, Cu-rGO exhibits obvious pseudocapacitive behavior. Under different current densities, Cu-rGO nanocomposites have high specific capacitance and good cycle stability, and can maintain high specific capacitance values ​​even at high current densities. Electrochemical impedance spectroscopy (EIS) tests show that Cu-rGO nanocomposites have low charge transfer impedance and good ion transport properties.

Claims

1. A method for synthesizing a copper particle decorated reduced graphene oxide nanocomposite material for supercapacitors, the method comprising the following steps: a) Synthesis of graphene oxide (GO) from graphite flakes using a modified Hummer method; b) Highly dispersed nano-copper particles were anchored on reduced graphene oxide (rGO) sheets via ethylene glycol (EG) reduction method to form copper particle-decorated reduced graphene oxide nanocomposites (Cu-rGO).

2. The synthesis method according to claim 1, wherein the modified Hummer method comprises adding a concentrated H2SO4 / H3PO4 mixture to a graphite sheet, followed by adding potassium permanganate (KMnO4) to synthesize graphene oxide (GO).

3. The synthesis method according to claim 1, wherein the ethylene glycol (EG) reduction method further comprises dispersing CuCl2 and PVP in an ethylene glycol solution, and then dispersing GO in the ethylene glycol solution, mixing and refluxing at a specific temperature to anchor the nano-copper particles on the rGO sheet.

4. A copper particle decorated reduced graphene oxide nanocomposite material, which is synthesized by the method described in claims 1-3, and the composite material has uniformly distributed copper nanoparticles with an average diameter between 8-9 nm.

5. The nanocomposite material according to claim 4, wherein the copper nanoparticles are completely fixed on the reduced graphene oxide sheet.

6. A method of using the copper particle decorated reduced graphene oxide nanocomposite material of claims 4-5 as a supercapacitor electrode material, the method comprising integrating the nanocomposite material into an electrode of a supercapacitor.

7. A supercapacitor, characterized in that The invention comprises at least one electrode, which is composed of the reduced graphene oxide nanocomposite material decorated with copper particles as claimed in claims 4-5.

8. An apparatus for preparing the copper particle decorated reduced graphene oxide nanocomposite material as claimed in the above claims, the apparatus comprising a chemical reactor for performing a modified Hummer process, a reflux device for performing an ethylene glycol (EG) reduction process, and filtering and drying equipment for post-treating and drying the obtained nanocomposite material.

9. The apparatus according to claim 8, wherein the chemical reactor is equipped with a temperature control system for precisely controlling the reaction temperature of synthesizing graphene oxide (GO), a reflux device for maintaining the ethylene glycol (EG) reduction reaction, and a filtering and drying device for separating the nanocomposite from the reaction mixture and drying it to a desired moisture content.