CN113603193B - Preparation method of graphene electrode for capacitive deionization - Google Patents
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Abstract
The invention belongs to the field of electrode material synthesis, and relates to a preparation method of a graphene electrode for capacitive deionization, which comprises the following steps: dispersing graphene oxide in deionized water, adding a polytetrafluoroethylene dispersion liquid, heating and stirring to obtain a semi-solid slurry, and rolling for multiple times by using an electric roller press to obtain a graphene oxide film electrode; cutting the thin film electrode into equal-size square pieces, placing the square pieces in a beaker, adding an L-ascorbic acid solution, heating and stirring to perform reduction reaction of the electrode, taking out the electrode after the reaction is finished, washing the electrode with deionized water and ethanol, soaking the electrode in ethanol, taking out the electrode, and air-drying the electrode to obtain the graphene electrode. The electrode material prepared by the invention has good stability, electrochemical performance and excellent capacitance desalting performance. The preparation method is simple in preparation process, environment-friendly and convenient to operate, provides technical support for large-scale low-cost preparation of the thin film electrode, and has wide application prospect in the aspect of electrode preparation of a capacitive deionization technology.
Description
Technical Field
The invention belongs to the field of electrode material synthesis, and particularly relates to a preparation method of a graphene electrode for capacitive deionization.
Background
With the rapid development of modern industrialization process and the continuous increase of population, the crisis of fresh water resources has gradually become a global problem, and the desalination and recycling of brackish water and sewage resources become an important strategic direction for solving the shortage of fresh water. In recent decades, a novel desalination technology, namely Capacitive Deionization (CDI) technology, appears along with scientific development of carbon materials, provides a new choice for desalination of salt water and removal of heavy metal ions, makes up for the defects of the traditional desalination technology, and has practical possibility of low energy consumption and high efficiency.
Graphene has huge specific surface area (2630 m) due to its unique two-dimensional nanostructure 2 G) and ultrahigh conductivity (7200S/m), is considered as a new material with huge potential, has been widely researched and applied in the fields of solar cells, sensors, nanoelectronics and the like, and is also an ideal substitute of a CDI electrode material.
Disclosure of Invention
The invention aims to prepare a graphene electrode material for capacitive deionization by a simple, convenient, efficient and low-cost method.
The method adopted by the invention is to firstly carry out the molding preparation of the graphene oxide electrode slice: the surface of the graphene oxide is provided with a large number of oxygen-containing functional groups, the graphene oxide is easy to mix with water molecules to form stable dispersion liquid, certain interlayer spacing is kept between the groups due to the mutual repulsion action of Van der Waals force, and the groups are prepared into slurry by adding a binder and then are rolled to form a film; and then, placing the graphene oxide electrode plate in an L-ascorbic acid solution for reduction reaction, reducing oxygen-containing functional groups on the surface of the graphene oxide, keeping the interlayer spacing of the original structure, and providing more channels for the flow of sodium ions and chloride ions, so that the electrode has a better adsorption effect. The method has the advantages of simple process, environmental protection and convenient operation, provides technical support for preparing the thin film electrode in a large scale at low cost, and has wide application prospect in the aspect of electrode preparation of a capacitive deionization technology.
The invention relates to a preparation method of a graphene electrode for capacitive deionization, which comprises the following specific steps:
(1) Weighing Graphene Oxide (GO) in a beaker, adding deionized water, ultrasonically dispersing the Graphene Oxide (GO) in the beaker, and then placing the beaker under a homogenizer for high-speed stirring to obtain graphene oxide dispersion liquid;
wherein the mass of the Graphene Oxide (GO) is 9.0-11.0 g, the volume of the deionized water is 900-1100 ml, the ultrasonic frequency is 20-40 kHz, and the rotating speed of the homogenizer is 1000-1400 r/min.
(2) Weighing polytetrafluoroethylene powder in a beaker, adding ethanol, and uniformly stirring under a homogenizer to obtain polytetrafluoroethylene dispersion;
wherein, the mass of the polytetrafluoroethylene is 0.95 to 1.05g, the volume of the ethanol is 40 to 60ml, and the rotating speed of the homogenizer is 1000 to 1400r/min.
(3) Placing the graphene oxide dispersion liquid obtained in the step (1) into a water bath kettle, heating and stirring, and dropwise adding the polytetrafluoroethylene dispersion liquid obtained in the step (2) in the stirring process to obtain graphene oxide slurry;
wherein the temperature of the constant temperature water bath kettle is 50-70 ℃, the stirring speed is 400-500 r/min, and the stirring time is 1-4 h.
(4) Pouring the graphene oxide slurry obtained in the step (3) into a culture dish, and placing the culture dish in a forced air drying box for drying to obtain semi-solid graphene oxide slurry; then rolling the semi-solid slurry by using an electric roller press to obtain a graphene oxide electrode material; cutting the obtained graphene oxide electrode material into a plurality of square sheets, weighing, filling the square sheets into a nylon filter screen bag, and placing the nylon filter screen bag into a beaker filled with deionized water;
wherein, the temperature of the blast drying box is 40-60 ℃, the drying time is 3.5-5.5 h, the distance between the rollers of the electric roller press is 10-1000 μm, and the rotating speed is 10-90 r/min; the graphene oxide electrode is cut into square pieces with the size of 8cm multiplied by 8cm, the average mass of each piece is 0.8g, and a nylon filter screen is 50 meshes.
(5) Weighing L-ascorbic acid according to the weight of the graphene oxide electrode plate obtained in the step (4) in proportion, adding deionized water, uniformly stirring to obtain an L-ascorbic acid solution, adding the L-ascorbic acid solution into the beaker containing the graphene oxide electrode plate in the step (5), and carrying out reduction reaction under the conditions of water bath heating and stirring;
wherein the mass ratio of the L-ascorbic acid to the graphene oxide electrode plate is 0.35-0.45, and the stirring speed is 400-600 r/min; the water bath heating temperature is 80-90 ℃, and the reaction time is 24-48 h.
(6) And (4) taking out the electrode slice after the reaction in the step (5), washing the electrode slice for a plurality of times by using deionized water and ethanol, soaking the electrode slice in an ethanol solution, finally taking out the electrode slice, and naturally drying the electrode slice at room temperature to obtain the graphene electrode material. Wherein the soaking time is 0.5-2 days.
The invention has the beneficial effects that:
the fully reduced graphene monomers tend to form agglomerates by secondary stacking due to the inter-layer attraction. From the perspective of the porous material, the pore channels of the graphene material are mainly formed by the intervals between layers, and the formation of a large number of secondary stacking can reduce the overall effective specific surface area and pore channel network and prevent the improvement of the electroadsorption and desorption performance of the graphene material. The electrode material prepared by the invention has good stability, electrochemical performance and excellent capacitance desalting performance. The method has the advantages of simple process, environmental protection and convenient operation, provides technical support for preparing the thin film electrode in a large scale at low cost, and has wide application prospect in the aspect of electrode preparation of a capacitive deionization technology.
Drawings
Fig. 1 is an XRD spectrum of the graphene electrode material prepared in each example; wherein, fig. 1 (a) is an XRD pattern of the graphene oxide electrode and examples 1, 2, 3, 4, 5, and fig. 1 (b) is an XRD pattern of the graphene oxide raw material and comparative example 1;
fig. 2 is a Raman spectrum of graphene oxide and graphene prepared in example 1;
FIG. 3 is a graph showing adsorption curves of the graphene electrode material prepared in example 1 on a 250mg/L NaCl solution at different voltages;
fig. 4 is a graph comparing cyclic voltammograms of the graphene electrode materials prepared in example 1 and comparative example 1;
fig. 5 is a graph comparing the adsorption curves of the graphene electrode materials prepared in example 1, example 2, example 3, example 4, example 5 and comparative example 1 at a voltage of 2.5V for a 250mg/L NaCl solution;
fig. 6 is a conductivity change curve corresponding to the graphene electrode material prepared in example 1, which is obtained by performing a desorption cycle on a 250mg/L NaCl solution under a voltage condition of 2.5V using a CDI apparatus.
Detailed Description
The preparation method of the graphene electrode for capacitive deionization provided by the invention can be implemented by the following steps:
example 1
Weighing 10.0g of Graphene Oxide (GO) into a beaker, adding 1000ml of deionized water, placing the beaker under 40kHz of frequency for ultrasonic dispersion for 2 hours, and then homogenizing and stirring the mixture for 4 times under a homogenizer of 1200r/min to obtain graphene oxide dispersion liquid; weighing 1.0g of polytetrafluoroethylene powder, adding 50ml of ethanol, and uniformly stirring to obtain polytetrafluoroethylene dispersion; setting the temperature of a constant-temperature water bath kettle to be 60 ℃, stirring at the speed of 450r/min, placing the graphene oxide dispersion liquid in the kettle, heating and stirring for 2.5 hours, and dropwise adding the polytetrafluoroethylene dispersion liquid in the stirring process to obtain graphene oxide slurry; pouring the graphene oxide slurry into a culture dish, placing the culture dish in a forced air drying oven, setting the temperature to be 50 ℃, and drying for 4.5 hours to obtain semi-solid graphene oxide slurry; then rolling the semi-solid slurry by adopting an electric roller press at the roller speed of 30r/min for 10 times at the roller spacing of 500 microns, adjusting the roller spacing to 400 microns, and rolling for 10 times at the roller spacing of 300 microns, 200 microns and 150 microns in sequence to obtain the graphene oxide electrode material with the thickness of 150 microns; cutting the graphene oxide electrode material into 10 square pieces of 8cm multiplied by 8cm, wherein the average mass is 0.8g, clamping an electrode piece between every two square nylon filter screens of 10cm multiplied by 10cm, stacking the electrode pieces into 50-mesh nylon filter screen bags, and placing the nylon filter screen bags into a beaker filled with deionized water; weighing 4.0g of L-ascorbic acid, adding 50ml of deionized water, uniformly stirring to obtain an L-ascorbic acid solution, pouring the L-ascorbic acid solution into a beaker containing a graphene oxide electrode plate, and reacting for 36 hours under the conditions that the heating temperature is 85 ℃ and the stirring speed is 500 r/min; and taking out the electrode slice, washing with deionized water for 5 times, washing with ethanol for 5 times, soaking in an ethanol solution for 1d, taking out, and naturally air-drying to finally obtain the graphene electrode material.
Example 2
Weighing 9.0g of Graphene Oxide (GO) in a beaker, adding 9000ml of deionized water, placing the beaker at the frequency of 20kHz, performing ultrasonic dispersion for 4 hours, and performing homogenization stirring for 5 times in a homogenizer at the speed of 1000r/min to obtain a graphene oxide dispersion liquid; weighing 0.95g of polytetrafluoroethylene powder, adding 50ml of ethanol, and uniformly stirring to obtain polytetrafluoroethylene dispersion; setting the temperature of a constant-temperature water bath kettle to be 50 ℃, stirring at the speed of 400r/min, placing the graphene oxide dispersion liquid in the kettle, heating and stirring for 4 hours, and dropwise adding the polytetrafluoroethylene dispersion liquid in the stirring process to obtain graphene oxide slurry; pouring the graphene oxide slurry into a culture dish, placing the culture dish in a forced air drying oven, setting the temperature to be 40 ℃, and drying for 5.5 hours to obtain semi-solid graphene oxide slurry; then rolling the semi-solid slurry in an electric roller press at the roller speed of 40r/min for 10 times at the roller spacing of 600 microns, adjusting the roller spacing to 500 microns, and rolling for 10 times at the roller spacing of 400 microns, 300 microns, 200 microns and 150 microns in sequence to obtain the graphene oxide electrode material with the thickness of 150 microns; cutting the graphene oxide electrode material into 10 square pieces of 8cm multiplied by 8cm, wherein the average mass is 0.8g, clamping an electrode piece between every two square nylon filter screens of 10cm multiplied by 10cm, stacking the electrode pieces into 50-mesh nylon filter screen bags, and placing the nylon filter screen bags into a beaker filled with deionized water; weighing 3.2g of L-ascorbic acid, adding 50ml of deionized water, uniformly stirring to obtain an L-ascorbic acid solution, pouring the L-ascorbic acid solution into a beaker filled with a graphene oxide electrode plate, and reacting for 48 hours under the conditions that the heating temperature is 80 ℃ and the stirring speed is 400 r/min; and taking out the electrode slice, washing with deionized water for 5 times, washing with ethanol for 5 times, soaking in an ethanol solution for 2 days, taking out, and naturally air-drying to finally obtain the graphene electrode material.
Example 3
Weighing 11.0g of Graphene Oxide (GO) in a beaker, adding 1100ml of deionized water, placing the beaker under the frequency of 30kHz, performing ultrasonic dispersion for 3 hours, and performing homogenization stirring for 3 times under a homogenizer of 1400r/min to obtain a graphene oxide dispersion liquid; weighing 1.05g of polytetrafluoroethylene powder, adding 50ml of ethanol, and uniformly stirring to obtain polytetrafluoroethylene dispersion; setting the temperature of a constant-temperature water bath kettle to be 70 ℃, stirring at the speed of 500r/min, placing the graphene oxide dispersion liquid in the kettle, heating and stirring for 1h, and dropwise adding the polytetrafluoroethylene dispersion liquid in the stirring process to obtain graphene oxide slurry; pouring the graphene oxide slurry into a culture dish, placing the culture dish in a forced air drying oven, setting the temperature to be 60 ℃, and drying for 3.5 hours to obtain semi-solid graphene oxide slurry; then rolling the semi-solid slurry in an electric roller press at the roller speed of 20r/min for 10 times at the roller spacing of 400 microns, adjusting the roller spacing to 300 microns, and rolling for 10 times at the roller spacing of 200 microns and 150 microns in sequence to obtain the graphene oxide electrode material with the thickness of 150 microns; cutting the graphene oxide electrode material into 10 square pieces of 8cm multiplied by 8cm, wherein the average mass is 0.8g, clamping an electrode piece between every two square nylon filter screens of 10cm multiplied by 10cm, stacking the electrode pieces into 50-mesh nylon filter screen bags, and placing the nylon filter screen bags into a beaker filled with deionized water; weighing 4.8g of L-ascorbic acid, adding 50ml of deionized water, uniformly stirring to obtain an L-ascorbic acid solution, pouring the L-ascorbic acid solution into a beaker containing a graphene oxide electrode plate, and reacting for 24 hours under the conditions that the heating temperature is 90 ℃ and the stirring speed is 600r/min; and taking out the electrode slice, washing with deionized water for 5 times, washing with ethanol for 5 times, soaking in an ethanol solution for 0.5d, taking out, and naturally air-drying to finally obtain the graphene electrode material.
Example 4
Weighing 10.0g of Graphene Oxide (GO) in a beaker, adding 1000ml of deionized water, placing the beaker under the frequency of 40kHz, performing ultrasonic dispersion for 2 hours, and performing homogenization stirring for 4 times under a homogenizer of 1200r/min to obtain a graphene oxide dispersion liquid; weighing 1.0g of polytetrafluoroethylene powder, adding 50ml of ethanol, and uniformly stirring to obtain polytetrafluoroethylene dispersion; setting the temperature of a constant-temperature water bath kettle to be 60 ℃, setting the stirring speed to be 450r/min, placing the graphene oxide dispersion liquid in the kettle, heating and stirring for 2.5 hours, and dropwise adding the polytetrafluoroethylene dispersion liquid in the stirring process to obtain graphene oxide slurry; pouring the graphene oxide slurry into a culture dish, placing the culture dish in a forced air drying oven, setting the temperature to be 50 ℃, and drying for 4.5 hours to obtain semi-solid graphene oxide slurry; then rolling the semi-solid slurry by adopting an electric roller press at the roller speed of 30r/min for 10 times at the roller spacing of 500 microns, adjusting the roller spacing to 400 microns, and rolling for 10 times at the roller spacing of 300 microns, 200 microns and 150 microns in sequence to obtain the graphene oxide electrode material with the thickness of 150 microns; cutting the graphene oxide electrode material into 10 pieces of square pieces with the average mass of 0.8g and the length of 8cm multiplied by 8cm, clamping an electrode piece between every two square nylon filter screens with the average mass of 0.8g, stacking the electrode pieces into 50-mesh nylon filter screen bags, and placing the nylon filter screen bags into a beaker filled with deionized water; weighing 4.5g of L-ascorbic acid, adding 50ml of deionized water, uniformly stirring to obtain an L-ascorbic acid solution, pouring the L-ascorbic acid solution into a beaker filled with a graphene oxide electrode plate, and reacting for 36 hours under the conditions that the heating temperature is 85 ℃ and the stirring speed is 500 r/min; and taking out the electrode slice, washing with deionized water for 5 times, washing with ethanol for 5 times, soaking in an ethanol solution for 1d, taking out, and naturally air-drying to finally obtain the graphene electrode material.
Example 5
Weighing 10.0g of Graphene Oxide (GO) into a beaker, adding 1000ml of deionized water, placing the beaker under 40kHz of frequency for ultrasonic dispersion for 2 hours, and then homogenizing and stirring the mixture for 4 times under a homogenizer of 1200r/min to obtain graphene oxide dispersion liquid; weighing 1.0g of polytetrafluoroethylene powder, adding 50ml of ethanol, and uniformly stirring to obtain polytetrafluoroethylene dispersion; setting the temperature of a constant-temperature water bath kettle to be 60 ℃, stirring at the speed of 450r/min, placing the graphene oxide dispersion liquid in the kettle, heating and stirring for 2.5 hours, and dropwise adding the polytetrafluoroethylene dispersion liquid in the stirring process to obtain graphene oxide slurry; pouring the graphene oxide slurry into a culture dish, placing the culture dish in a forced air drying oven, setting the temperature to be 50 ℃, and drying for 4.5 hours to obtain semi-solid graphene oxide slurry; then rolling the semi-solid slurry by adopting an electric roller press at the roller speed of 30r/min for 10 times at the roller spacing of 500 microns, adjusting the roller spacing to 400 microns, and rolling for 10 times at the roller spacing of 300 microns, 200 microns and 150 microns in sequence to obtain the graphene oxide electrode material with the thickness of 150 microns; cutting the graphene oxide electrode material into 10 square pieces of 8cm multiplied by 8cm, wherein the average mass is 0.8g, clamping an electrode piece between every two square nylon filter screens of 10cm multiplied by 10cm, stacking the electrode pieces into 50-mesh nylon filter screen bags, and placing the nylon filter screen bags into a beaker filled with deionized water; weighing 3.5g of L-ascorbic acid, adding 50ml of deionized water, uniformly stirring to obtain an L-ascorbic acid solution, pouring the L-ascorbic acid solution into a beaker containing a graphene oxide electrode plate, and reacting for 36 hours under the conditions that the heating temperature is 85 ℃ and the stirring speed is 500 r/min; and taking out the electrode slice, washing with deionized water for 5 times, washing with ethanol for 5 times, soaking in an ethanol solution for 1d, taking out, and naturally air-drying to finally obtain the graphene electrode material.
Comparative example 1
Weighing 10.0g of Graphene Oxide (GO) in a beaker, adding 1000ml of deionized water, placing the beaker under the frequency of 40kHz, performing ultrasonic dispersion for 2 hours, and performing homogenization stirring for 4 times under a homogenizer of 1200r/min to obtain a graphene oxide dispersion liquid; weighing 4.0g of L-ascorbic acid, adding 50ml of deionized water, uniformly stirring to obtain an L-ascorbic acid solution, slowly pouring the L-ascorbic acid solution into the graphene oxide solution, reacting for 36 hours at the heating temperature of 85 ℃ and the stirring speed of 500r/min, repeatedly cleaning and filtering with the deionized water and an ethanol solution after the reaction is finished, and drying the obtained filter cake for 24 hours in a vacuum drying oven at the temperature of 60 ℃ to obtain reduced graphene oxide powder; weighing 5.0g of prepared graphene and 0.5g of polytetrafluoroethylene powder, dissolving the graphene and the polytetrafluoroethylene powder in an ethanol solution, and heating and stirring the solution in a constant-temperature water bath kettle at the temperature of 60 ℃ and the stirring speed of 450r/min for 2.5 hours to obtain graphene slurry; pouring the graphene slurry into a culture dish, placing the culture dish in a forced air drying oven, setting the temperature to be 50 ℃, and drying for 4.5 hours to obtain semi-solid graphene slurry; and then rolling the semi-solid slurry in an electric roller press at the roller speed of 30r/min for 10 times at the roller spacing of 500 microns, adjusting the roller spacing to 400 microns, and rolling for 10 times at the roller spacing of 300 microns, 200 microns and 150 microns in sequence to finally obtain the graphene electrode material with the thickness of 150 microns.
Fig. 1 (a) is an XRD pattern of the graphene oxide electrode and examples 1, 2, 3, 4, and 5, and fig. 1 (b) is an XRD pattern of the graphene oxide raw material and comparative example 1. The graphene oxide electrode and the graphene oxide raw material have a strong diffraction peak near 10 degrees 2 theta, which is a graphite oxide (001) crystal plane diffraction peak, and after the reduction reaction, the peak disappears, the samples of examples 1, 2, 3, 4 and 5 have a diffraction peak near 25 degrees 2 theta, while the sample of comparative example 1 has a diffraction peak near 23 degrees 2 theta, and the peaks of the two are both broadened and weakened, which indicates that the experimental products of examples 1, 2, 3, 4 and 5 and comparative example 1 all contain graphene. In FIG. 1 (a), a diffraction peak of polytetrafluoroethylene appears at around 18 ℃ 2. Theta. In the above embodiment, the ratio of the L-ascorbic acid to the graphene oxide is controlled within a certain range, and the sample can be reduced to obtain the graphene.
FIG. 2 is a Raman spectrum of graphene oxide and graphene prepared in example 1, wherein a G band (about 1580 cm) is visible -1 ) And D band (about 1350 cm) -1 ) I of reduced graphene oxide D /I G The value of (1.153) is larger than that of graphene oxide (1.041), I D /I G The increase of ratio shows that the defect degree increases, and the defect degree is bigger, strengthens electron conduction to promote the adsorption effect of electrode.
Fig. 3 shows that the adsorption test of the graphene electrode material prepared in example 1 on 250mg/L NaCl solution by using a CDI apparatus under different voltages shows that the adsorption effect is more and more obvious as the voltage increases, and when the voltage reaches 2.5V, the time for reaching the adsorption equilibrium state is shorter, and the salt rejection rate reaches 47%.
FIG. 4 is a graph of the results of example 1 and comparative example 1The capacitance performance of the electrode made of the graphene electrode material by using an electrochemical workstation is tested, and the prepared electrode material is prepared in a sodium chloride solution with 1mol/L electrolyte and the effective area of the electrode is 1 multiplied by 1cm 2 The sweep rate is 50mV/s, and cyclic voltammetry tests are carried out, and both obtain a similar rectangular chart, which shows that obvious redox reaction does not occur in the charging and discharging process, and the electrodes prepared by the two methods mainly have the capacitance performance of a double electron layer and have good reversibility; the area enclosed by the electrode material in example 1 is larger than that in comparative example 1, the capacitance capacity of the electrode material in example 1 can reach 136F/g through calculation, the capacitance capacity of the electrode material in comparative example 1 is 88F/g, and the electrode prepared in example 1 has excellent electrochemical performance.
Fig. 5 is an adsorption test of the graphene electrode materials prepared in examples 1, 2, 3, 4, 5 and comparative example 1 on a 250mg/L NaCl solution under a voltage condition of 2.5V using a CDI apparatus, wherein the electrodes of examples 1, 2, 3, 4, 5 all start to enter an adsorption equilibrium stage after 20 minutes, and the electrode of comparative example enters the adsorption equilibrium stage only after thirty minutes; the conductivity decrease of examples 1, 2, 3, 4 and 5 is more obvious than that of comparative example 1, the salt rejection of example 1 is 47%, the salt rejection of example 2 is 46.2%, the salt rejection of example 3 is 46.7%, the salt rejection of example 4 is 46.5%, the salt rejection of example 5 is 46.4%, and the salt rejection of comparative example 1 is 37.4%, and the salt rejection of the examples is improved by nearly 10% compared with that of the comparative example, which shows that the graphene electrode material prepared in the examples has more excellent salt rejection performance.
Fig. 6 is a change curve of conductivity corresponding to the adsorption and desorption cycle of the graphene electrode material prepared in example 1 performed on 250mg/L NaCl solution under a voltage of 2.5V by using a CDI apparatus, wherein a dc voltage of 2.5V is applied to two ends of the electrode in the adsorption stage, and the two ends of the electrode are short-circuited in the desorption stage until the conductivity of the solution returns to the initial value. As can be seen from the figure, after several cycles of adsorption-desorption, the conductivity changes stably, and the curve still maintains a better shape, which indicates that the graphene electrode material prepared in example 1 has good cycle stability and can be continuously used in desalination.
It should be noted that the above-mentioned embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the content of the present invention and to implement the present invention, and therefore, the protection scope of the present invention should not be limited by the above-mentioned embodiments.
Claims (6)
1. A preparation method of a graphene electrode for capacitive deionization is characterized by comprising the following steps:
(1) Weighing Graphene Oxide (GO) in a beaker, adding deionized water, performing ultrasonic dispersion on the mixture, and placing the mixture under a homogenizer for high-speed stirring to obtain a graphene oxide dispersion liquid;
(2) Weighing polytetrafluoroethylene powder in a beaker, adding ethanol, and placing under a homogenizer for uniform stirring to obtain polytetrafluoroethylene dispersion;
(3) Placing the graphene oxide dispersion liquid obtained in the step (1) into a water bath kettle, heating and stirring, and dropwise adding the polytetrafluoroethylene dispersion liquid obtained in the step (2) in the stirring process to obtain graphene oxide slurry;
(4) Pouring the graphene oxide slurry obtained in the step (3) into a culture dish, and placing the culture dish in a forced air drying box for drying to obtain semi-solid graphene oxide slurry; then rolling the semi-solid slurry by using an electric roller press to obtain a graphene oxide electrode material; cutting the obtained graphene oxide electrode material into square pieces, filling the square pieces into a nylon filter bag, and placing the nylon filter bag into a beaker filled with deionized water;
(5) Weighing L-ascorbic acid, adding deionized water, uniformly stirring to obtain an L-ascorbic acid solution, adding the L-ascorbic acid solution into the beaker containing the graphene oxide electrode plate in the step (4), and carrying out reduction reaction under the conditions of water bath heating and stirring;
the mass ratio of the L-ascorbic acid to the graphene oxide electrode plate is 0.35-0.45; the water bath heating temperature is 80-90 ℃, the stirring speed is 400-600 r/min, and the reaction time is 24-48 h;
(6) And (4) taking out the electrode slice after the reaction in the step (5), washing the electrode slice with deionized water and ethanol, soaking the electrode slice in an ethanol solution for 0.5-2 days, finally taking out the electrode slice, and naturally drying the electrode slice at room temperature to obtain the graphene electrode material.
2. The method of preparing a graphene electrode for capacitive deionization according to claim 1, wherein: the mass of the graphene oxide in the step (1) is 9.0-11.0 g, the volume of deionized water is 900-1100 ml, the ultrasonic frequency is 20-40 kHz, and the rotating speed of a homogenizer is 1000-1400 r/min.
3. The method of preparing a graphene electrode for capacitive deionization according to claim 1, wherein: the mass of the polytetrafluoroethylene in the step (2) is 0.95-1.05 g, the volume of the ethanol is 40-60 ml, and the rotating speed of a homogenizer is 1000-1400 r/min.
4. The method of preparing a graphene electrode for capacitive deionization according to claim 1, wherein: the temperature of the constant temperature water bath kettle in the step (3) is 50-70 ℃, the stirring speed is 400-500 r/min, and the stirring time is 1-4 h.
5. The method of preparing a graphene electrode for capacitive deionization according to claim 1, wherein: and (4) drying the air-blast drying box at the temperature of 40-60 ℃ for 3.5-5.5 h, wherein the distance between rollers of the electric roller press is 10-1000 mu m, and the rotating speed is 10-90 r/min.
6. The method of preparing a graphene electrode for capacitive deionization of claim 1, wherein: and (5) cutting the graphene oxide electrode into square pieces with the size of 8cm multiplied by 8cm, wherein the average mass of the single pieces is 0.8g, and the nylon filter screen is 50 meshes.
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| CN109575467A (en) * | 2018-10-24 | 2019-04-05 | 山东鲁泰控股集团有限公司石墨烯高分子复合材料研发中心 | A kind of preparation method of graphene-PVC composite material |
| CN112708152A (en) * | 2020-12-25 | 2021-04-27 | 厦门大学 | Preparation method of high-thermal-conductivity graphite aerogel-based composite thermal interface material |
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| CN105788879A (en) * | 2016-04-27 | 2016-07-20 | 东华大学 | Graphene film and continuous preparation method thereof |
| CN106124592A (en) * | 2016-07-07 | 2016-11-16 | 上海交通大学 | A kind of composite electrochemical deposition preparation modified for microelectrode |
| CN107265506A (en) * | 2017-08-03 | 2017-10-20 | 山东金城石墨烯科技有限公司 | A kind of preparation method of metal Mn oxide/graphene composite material |
| CN109575467A (en) * | 2018-10-24 | 2019-04-05 | 山东鲁泰控股集团有限公司石墨烯高分子复合材料研发中心 | A kind of preparation method of graphene-PVC composite material |
| CN112708152A (en) * | 2020-12-25 | 2021-04-27 | 厦门大学 | Preparation method of high-thermal-conductivity graphite aerogel-based composite thermal interface material |
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