Composition for electrode, capacitance deionization electrode and use

Abstract

The present application relates to a composition for an electrode, a capacitance deionization electrode and the use. The composition for an electrode comprises a porous carbon material, an oxidation-modified conductive carbon material and a binder, and the mass ratio of the binder to the porous carbon material to the oxidation-modified conductive carbon material is 1: (4-96): (0.2-15).

Description

Electrode composition, capacitive deionization electrode and application

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202411061024.8, filed on August 2, 2024, entitled "Electrode composition, capacitive deionization electrode and application", the content of the above patent application is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of water treatment, in particular to an electrode composition, a capacitive deionization electrode and application. BACKGROUND

[0004] Capacitive deionization technology generally uses a capacitor as the core component of a deionization device. When water flows through the capacitor, the electric field on the electrode separates the ions with different charges in the water. This technology can remove various ions in water, including sodium, magnesium, calcium, iron, copper, lead, chlorine, carbonate, sulfate, etc., so as to achieve the purpose of purifying water quality. Capacitive deionization technology has the advantages of high efficiency, energy saving, environmental protection, etc., and has wide application prospects in the field of water treatment (including seawater and brackish water desalination, salt lake lithium extraction, drinking water purification, water quality softening, etc.).

[0005] The capacitor in capacitive deionization technology is also called super capacitor. The specific surface area and charge storage method of super capacitor are different from those of ordinary capacitor. Compared with the capacity of ordinary capacitor which is usually only a few microfarads or millifarads, the capacity of super capacitor can reach hundreds or even thousands of farads.

[0006] The key core of capacitive deionization technology lies in the electrode material of super capacitor. At present, activated carbon has shown good deionization performance in capacitive deionization technology, but there are the following problems in the process of commercial application of activated carbon: (1) Although the specific surface area of activated carbon is large, its pore size distribution is mainly microporous (<2 nm), which has certain limiting effect on the mass transfer and diffusion of hydrated ions, and the poor hydrophilicity of activated carbon itself leads to its application in capacitive deionization being limited; (2) The conductivity of activated carbon itself is not high, and the resistance is high, so a poor-conductive polymer binder needs to be added in the process of electrode preparation, therefore, the conductivity of activated carbon electrode material is generally poor. SUMMARY

[0007] The present application aims to at least solve one of the above technical problems in the prior art. To this end, one of the purposes of the present application is to provide an electrode composition.

[0008] The second purpose of the present application is to provide a preparation method of the above electrode composition.

[0009] A third object of the present application is to provide a capacitive deionization electrode.

[0010] A fourth object of the present application is to provide a water treatment device.

[0011] A fifth object of the present application is to provide the use of the electrode composition and / or the capacitive deionization electrode in the field of water treatment.

[0012] To achieve the above objects, the technical solution adopted by the present application is as follows:

[0013] The first aspect of the present application provides an electrode composition comprising a porous carbon material, an oxidatively modified conductive carbon material and a binder, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material being 1:(4-96):(0.2-15).

[0014] The technical solution of the present application regarding the electrode composition has at least the following beneficial effects: the introduction of the oxidatively modified conductive carbon material with excellent conductive performance into the porous carbon material can improve the overall conductive performance of the electrode composition, the charge can be quickly transmitted in the electrode prepared from the electrode composition, thereby improving the desalination rate of the electrode. The oxidatively modified conductive carbon material will make the conductive carbon material contain oxygen-containing functional groups, which can be connected with the porous carbon material through the interaction between the functional groups and / or the physical entanglement effect, improve the dispersibility of the porous carbon material, avoid the agglomeration phenomenon of the porous carbon material caused by the electrostatic effect, and also reduce the amount of the binder used when preparing the electrode, thereby reducing the influence of the non-conductive binder on the conductive performance of the electrode composition.

[0015] According to some embodiments of the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material is 1:(5-96):(0.2-15), for example: 1:5:0.2, 1:5:5, 1:5:15, 1:6:0.2, 1:6:8, 1:6:15, 1:8:0.8, 1:8:1.2, 1:8:2, 1:8:5, 1:8:15, 1:9:0.8, 1:9:0.9, 1:9:1, 1:9:1.2, 1:10:0.2, 1:10:0.8, 1:10:0.9, 1:10:1, 1:10:1.5, 1:10:2, 1:10:2.5, 1:11:0.8, 1:11:0.9, 1:11:1, 1:11:1.2, 1:11:1.8, 1:11:2, 1:11:2.5, 1:12:0.8, 1:12:1.4, 1:12:1.9, 1:12:2.5, 1:13:0.8, 1:13:0.9, 1:13:1, 1:13:1.2, 1:13:1.8, 1:13:2, 1:13:2.5, 1:14:0.8, 1:14:0.9, 1:14:1, 1:14:1.2, 1:14:1.8, 1:14:2, 1:14:2.5, 1:15:0.2, 1:15:10, 1:15:15, 1:16:0.8, 1:16:0.9, 1:16:1, 1:16:1.2, 1:16:1.8, 1:16:3, 1:16:5, 1:20:0.2, 1:20:6, 1:20:15, 1:30:0.2, 1:30:5, 1:30:15, 1:40:0.2, 1:40:13, 1:50:0.2, 1:50:11, 1:60:0.2, 1:60:15, 1:70:0.2, 1:70:5, 1:70:15, 1:80:5, 1:80:10, 1:90:5, 1:90:15, 1:96:5, 1:96:10, 1:96:15; according to some embodiments of the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material is 1:(5-50):(0.5-8); according to some embodiments of the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material is 1:(5-35):(0.5-5); according to some embodiments of the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material is 1:(10-16):(0.8-2.5).

[0016] In the present application, the mass ratio of the binder, the porous carbon material, and the oxidatively modified conductive carbon material needs to satisfy the above range. Since the binder is generally a non-conductive material, if the amount of the binder used is high, the conductivity of the electrode composition will be affected, and if the amount of the binder used is low, the oxidatively modified conductive carbon material and the porous carbon material will easily fall off during the preparation of the electrode, affecting the service life of the electrode and the desalination rate. If the amount of the oxidatively modified conductive carbon material used is low, the improvement in conductivity will be small, and if the amount of the oxidatively modified conductive carbon material used is high, the desalination effect will be affected; if the amount of the porous carbon material used is high, the dispersibility of the porous carbon material will be poor, and agglomeration will occur, which is not conducive to obtaining an electrode composition with uniform composition; and if the amount of the porous carbon material used is low, the desalination effect will be affected.

[0017] In the present application, the mass ratio of the binder, the porous carbon material, and the oxidatively modified conductive carbon material needs to satisfy the above range. Since the binder is generally a non-conductive material, if the amount of the binder used is high, the conductivity of the electrode composition will be affected, and if the amount of the binder used is low, the oxidatively modified conductive carbon material and the porous carbon material will easily fall off during the preparation of the electrode, affecting the service life of the electrode and the desalination rate. If the amount of the oxidatively modified conductive carbon material used is low, the improvement in conductivity will be small, and if the amount of the oxidatively modified conductive carbon material used is high, the desalination effect will be affected; if the amount of the porous carbon material used is high, the dispersibility of the porous carbon material will be poor, and agglomeration will occur, which is not conducive to obtaining an electrode composition with uniform composition; and if the amount of the porous carbon material used is low, the desalination effect will be affected.

[0018] According to some embodiments of the present application, at least part of the porous carbon material and the oxidatively modified conductive carbon material in the electrode composition are connected by hydrogen bonds and / or physical entanglement. In the electrode composition of the present application, the oxidatively modified conductive carbon material contains oxygen-containing functional groups, and the surface of the porous carbon material also contains some oxygen-containing functional groups. Part of the oxygen-containing functional groups in the porous carbon material and the oxidatively modified conductive carbon material form hydrogen bonds and are connected together by hydrogen bonds, and / or part of the porous carbon material and the oxidatively modified conductive carbon material exist in physical entanglement, and are dispersed by hydrogen bonds and / or physical entanglement, improving the dispersibility of the porous carbon material, avoiding the agglomeration of the porous carbon material caused by electrostatic interaction, and reducing the amount of the binder used during the preparation of the electrode, thereby reducing the influence of the non-conductive binder on the conductivity of the electrode composition.

[0019] According to some embodiments of the present application, the porous carbon material is selected from activated carbon, oxidized activated carbon, or a combination thereof; according to some embodiments of the present application, the porous carbon material is oxidized activated carbon. When the porous carbon material is oxidized activated carbon, the amount of oxygen-containing functional groups in the porous carbon material is higher, and more hydrogen bonds can be formed between the oxidized activated carbon and the oxidized conductive carbon material. Compared with activated carbon, the use of oxidized activated carbon has better dispersion effect, and the effect of reducing the amount of binder is better. In addition, oxidized activated carbon has better hydrophilic effect than activated carbon, and is more suitable for use in the field of water treatment.

[0020] According to some embodiments of the present application, the oxidized activated carbon has a mass percentage of oxygen of 1-10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%; according to some embodiments of the present application, the oxidized activated carbon has a mass percentage of oxygen of 2-8%; according to some embodiments of the present application, the oxidized activated carbon has a mass percentage of oxygen of 4-7%. If the oxygen content of the oxidized activated carbon is too high (for example, greater than 10%), the conductivity of the electrode will be affected. If the oxygen content of the oxidized activated carbon is too low (for example, less than 1%), the dispersion of the oxidized activated carbon will decrease, and the amount of binder used will be relatively high.

[0021] According to some embodiments of the present application, the oxidized conductive carbon material has a mass percentage of oxygen of 1-30%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%; according to some embodiments of the present application, the oxidized conductive carbon material has a mass percentage of oxygen of 1-15%; according to some embodiments of the present application, the oxidized conductive carbon material has a mass percentage of oxygen of 1-10%; according to some embodiments of the present application, the oxidized conductive carbon material has a mass percentage of oxygen of 2-8%. If the oxygen content of the oxidized conductive carbon material is too high (for example, greater than 30%), the conductivity of the electrode will be affected. If the oxygen content of the oxidized conductive carbon material is too low (for example, less than 1%), the dispersion of the oxidized activated carbon will decrease, and the amount of binder used will be relatively high.

[0022] According to some embodiments of the present application, the conductive carbon material is selected from at least one of graphene, carbon nanotube, conductive carbon black, carbon fiber. The introduction of the conductive carbon material described above in the electrode composition of the present application can further improve the conductivity, and the surface of the conductive carbon material is modified by oxidation to have oxygen-containing functional groups, which can form hydrogen bonds with the porous carbon material, improve the dispersion effect of the porous carbon material, and reduce the amount of binder used.

[0023] According to some embodiments of the present application, the porous carbon material is in a particulate form; and the conductive carbon material is selected from carbon nanotube, carbon fiber, or a combination thereof. When the porous carbon material is in a particulate form and the conductive carbon material is in a non-particulate form (i.e., carbon nanotube, carbon fiber, or a combination thereof), it is beneficial for the physical entanglement between the non-particulate conductive carbon material and the particulate porous carbon material, and it is beneficial for the construction of a connected conductive network, which can improve the dispersion of the porous carbon material while reducing the amount of binder used.

[0024] According to some embodiments of the present application, the electrode composition further comprises a solvent. The solvent is used for the dispersion of the binder, the porous carbon material, and the oxidized conductive carbon material, which is beneficial for the processing of the electrode composition into an electrode and improves the processability of the electrode composition.

[0025] According to some embodiments of the present application, the mass percentage of the solvent in the electrode composition is 60-95%, for example, it can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%. According to some embodiments of the present application, the mass percentage of the solvent in the electrode composition is 60-80%. If the amount of solvent is too large, the solid content of the electrode composition is too low, which is not conducive to the processing of the electrode. If the amount of solvent is too small, the solid content of the electrode composition is too high, which is not conducive to the preparation of an electrode film with good thickness uniformity.

[0026] According to some embodiments of the present application, the solvent is selected from at least one of methanol, ethanol, ethylene glycol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide carbon tetrachloride, N-methyl pyrrolidone, and water. The solvent used in the present application has less environmental pollution, higher safety, lower cost, and is easy to evaporate, which is beneficial for obtaining an electrode film with high thickness uniformity.

[0027] According to some embodiments of the present application, the binder is selected from at least one of polyacrylic acid, polyethylene glycol, polyvinyl alcohol, polyamide acid, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, carboxymethyl cellulose, sodium hydroxymethyl cellulose, and styrene butadiene rubber. Compared with other binders in the prior art, the binder in the present application has less influence on the conductivity of the electrode composition when used, and has good compatibility with the porous carbon material and the oxidatively modified conductive carbon material.

[0028] According to some embodiments of the present application, the weight average molecular weight of the binder is 5000-2000000, for example, can be: 5000, 7000, 9000, 10000, 12000, 14000, 16000, 18000, 20000, 30000, 40000, 50000, 60000, 70000, 100000, 200000, 300000, 400000, 500000, 600000, 700000, 800000, 900000, 1000000, 1100000, 1200000, 1300000, 1400000, 1500000, 1600000, 1700000, 1800000, 1900000, 2000000. When the weight average molecular weight of the binder is too small, for example, less than 5000, the viscosity of the binder is small, and the binding effect is poor. When the weight average molecular weight of the binder is too large, for example, greater than 2000000, the viscosity of the binder is too large, which is not conducive to the dispersion of the porous carbon material and the oxidatively modified conductive carbon material.

[0029] The second aspect of the present application provides a preparation method of the electrode composition provided by the first aspect of the present application, comprising the following steps: mixing the oxidatively modified conductive carbon material, the porous carbon material, the binder, and optionally added solvent to obtain the electrode composition.

[0030] The technical scheme of the present application related to the preparation method of the electrode composition has at least the following beneficial effects: the present application uses oxidatively modified conductive carbon material, porous carbon material and binder as raw materials, which are widely available and low in cost. At the same time, the preparation method of the present application is obtained by uniformly mixing the raw materials physically, which is simple and mild in reaction conditions, has no requirements for equipment, and can be mass-produced industrially.

[0031] According to some embodiments of the present application, the preparation method comprises the following steps:

[0032] S1: mixing the binder with part of the solvent to obtain a binder dispersion; mixing the oxidatively modified conductive carbon material, the porous carbon material, and the remaining solvent to obtain a conductive dispersion;

[0033] S2: obtaining the electrode composition by mixing the binder dispersion liquid and the conductive dispersion liquid.

[0034] According to the preparation method of the present application, the binder dispersion liquid and the conductive dispersion liquid are prepared separately and then mixed, which is beneficial to the mixing and dispersion of the binder, the oxidized conductive carbon material and the porous carbon material, thereby avoiding the agglomeration of the porous carbon material due to the electrostatic interaction.

[0035] According to some embodiments of the present application, the mixing step in the preparation method is mixing at 15-40℃, for example, mixing at 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, 36℃, 37℃, 38℃, 39℃, 40℃. According to some embodiments of the present application, the mixing step in the preparation method is mixing at 20-35℃. The present application uses a lower mixing temperature, which can save energy and reduce costs.

[0036] According to some embodiments of the present application, the mixing time in the preparation method is 1-10h, for example, the mixing time can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h. The present application uses a mixing time of 1-10h, which can ensure uniform mixing of the raw materials and good dispersion of the porous carbon material and the oxidized conductive carbon material.

[0037] According to some embodiments of the present application, the mixing step is mixing by stirring. The present application uses stirring for mixing, which has lower requirements for equipment and can reduce production costs.

[0038] According to some embodiments of the present application, the stirring rate is 100-10000rpm, for example, it can be 100rpm, 200rpm, 400rpm, 500rpm, 600rpm, 800rpm, 1000rpm, 1200rpm, 1400rpm, 1600rpm, 1800rpm, 2000rpm, 3000rpm, 4000rpm, 5000rpm, 6000rpm, 7000rpm, 8000rpm, 9000rpm, 10000rpm. According to some embodiments of the present application, the stirring rate is 500-5000rpm. According to some embodiments of the present application, the stirring rate is 500-2000rpm. Stirring at a stirring rate of 100-10000rpm can fully disperse the porous carbon material and the oxidized conductive carbon material.

[0039] According to some embodiments of the present application, the step S2 is specifically: mixing the binder dispersion liquid and the conductive dispersion liquid, and then sieving to obtain the electrode composition. The sieving step can avoid the electrode composition containing large particles, affecting the subsequent use, and is beneficial to obtaining an electrode film with good thickness and composition uniformity.

[0040] According to some embodiments of the present application, the sieving step is performed by using a sieve with a mesh size of 50-500. If the mesh size of the sieve is too small, the particles in the electrode composition are too small, which is not conducive to the construction of a conductive network and the realization of the purpose of the present application, and affects the conductivity of the electrode composition. If the mesh size of the sieve is too large, the electrode composition contains large particles of raw materials, which is not conducive to obtaining an electrode film with good thickness and composition uniformity.

[0041] The third aspect of the present application provides a capacitive deionization electrode, comprising an electrode layer; the preparation raw material of the electrode layer is the electrode composition provided in the first aspect of the present application.

[0042] The technical scheme of the present application related to the capacitive deionization electrode has at least the following beneficial effects: the capacitive deionization electrode in the present application has a high desalination rate, a large specific surface area, a high pore volume, a low resistivity, a good service life and a good use stability; it can realize rapid and efficient removal of anions and cations in water, and has a good application prospect in the field of capacitive deionization water treatment.

[0043] According to some embodiments of the present application, the maximum adsorption speed of the anions and cations of the capacitive deionization electrode is 200-400 mg / (m 2 ·min), for example, it can be: 200 mg / (m 2 ·min), 210 mg / (m 2 ·min), 220 mg / (m 2 ·min), 230 mg / (m 2 ·min), 240 mg / (m 2 ·min), 250 mg / (m 2 ·min), 260 mg / (m 2 ·min), 270 mg / (m 2 ·min), 280 mg / (m 2 ·min), 290 mg / (m 2 ·min), 300 mg / (m 2 ·min), 310 mg / (m 2 ·min), 320 mg / (m 2 ·min), 330 mg / (m 2 ·min), 340 mg / (m 2• min), 350 mg / (m 2 • min), 360 mg / (m 2 • min), 370 mg / (m 2 • min), 380 mg / (m 2 • min), 390 mg / (m 2 • min), 400 mg / (m 2 • min); according to some embodiments of the present application, the maximum adsorption rate of anions and cations of the capacitive deionization electrode is 240-350 mg / (m 2 • min); according to some embodiments of the present application, the maximum adsorption rate of anions and cations of the capacitive deionization electrode is 240-330 mg / (m 2 • min). The capacitive deionization electrode in the present application has a large adsorption rate, which is conducive to faster adsorption and removal of positive and negative ions in water.

[0044] According to some embodiments of the present application, the specific surface area of the capacitive deionization electrode is 700-2500 m 2 / g, for example, can be: 700 m 2 / g, 800 m 2 / g, 900 m 2 / g, 1000 m 2 / g, 1100 m 2 / g, 1200 m 2 / g, 1300 m 2 / g, 1400 m 2 / g, 1500 m 2 / g, 1600 m 2 / g, 1700 m 2 / g, 1800 m 2 / g, 1900 m 2 / g, 2000 m 2 / g, 2100 m 2 / g, 2200 m 2 / g, 2300 m 2 / g, 2400 m 2 / g, 2500 m 2 / g. The specific surface area of the capacitive deionization electrode in the present application is large, which is conducive to obtaining a higher desalination rate.

[0045] According to some embodiments of the present application, the pore volume of the capacitive deionization electrode is 0.8-1.1 cm 3 / g, for example, can be 0.8 cm 3 / g, 0.85 cm 3 / g, 0.9 cm 3 / g, 0.95 cm 3 / g, 1.0 cm 3 / g, 1.05 cm 3 / g, 1.1 cm 3 / g; the capacitive deionization electrode in the present application has a proper pore volume, which is beneficial to the adsorption and deintercalation of positive and negative ions in water.

[0046] According to some embodiments of the present application, the resistivity of the capacitive deionization electrode is 0.3-0.7 Ω·cm, for example, can be 0.3 Ω·cm, 0.35 Ω·cm, 0.4 Ω·cm, 0.45 Ω·cm, 0.5 Ω·cm, 0.55 Ω·cm, 0.6 Ω·cm, 0.65 Ω·cm, 0.7 Ω·cm. The capacitive deionization electrode in the present application has a low resistivity and excellent conductivity.

[0047] According to some embodiments of the present application, the desalination rate of the capacitive deionization electrode is not less than 60% when the working voltage is 1.5-2 V, for example, the desalination rate can be 61%, 63%, 65%, 67%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, 98%, 100%. The capacitive deionization electrode in the present application has a high desalination rate in a wide voltage range.

[0048] According to some embodiments of the present application, the pore diameter of the pores in the capacitive deionization electrode is micron level.

[0049] The fourth aspect of the present application provides a water treatment device comprising the capacitive deionization electrode provided in the third aspect of the present application.

[0050] According to some embodiments of the present application, the water treatment device comprises a purified water device, a water desalination device, and a water quality softening device.

[0051] The fifth aspect of the present application provides the use of the electrode composition provided in the first aspect of the present application and / or the capacitive deionization electrode provided in the third aspect of the present application in the field of water treatment.

[0052] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 is a surface morphology diagram of the capacitive deionization electrode in Example 8.

[0054] Figure 2 is a desalination performance and voltage relationship curve test diagram of the capacitive deionization electrode in Example 8.

[0055] Figure 3 is a desalination performance and voltage relationship curve test diagram of the capacitive deionization electrode in Example 9. DETAILED DESCRIPTION

[0056] The specific implementation of the present application is further described in detail below in combination with the drawings and examples, but the implementation and protection of the present application are not limited thereto. It should be noted that if the following processes are not specifically described in detail, they can be implemented or understood by those skilled in the art with reference to the prior art. If the reagents or instruments used are not marked with the manufacturer, they are conventional products that can be purchased on the market.

[0057] When the inventors developed the composition for the capacitive deionization electrode, in order to solve the problems that the activated carbon has poor hydrophilicity and the pore size is mainly microporous, which affects the mass transfer and diffusion of hydrated ions, and the deionization efficiency and effect are poor, etc., the inventors tried to prepare porous carbon material electrodes by methods such as strong alkali heat treatment, template method, chemical vapor deposition method, etc. Although the specific surface area, pore size or hydrophilicity of the porous carbon material electrode has been improved to a certain extent, it still cannot meet the requirements of rapid and efficient adsorption of anions and cations in water, and the porous carbon material prepared by these methods all has certain defects. These defects can improve the hydrophilicity of the porous carbon material, but also reduce the conductivity of the porous carbon material to a certain extent. Based on this, the inventors continue to develop the porous carbon material electrode, and try to heat treat the porous carbon material to reduce the defects on the surface of the porous carbon material, and the conductivity of the porous carbon material has been improved to a certain extent, but it still cannot meet the use requirements. In addition, the strong alkali heat treatment, template method, chemical vapor deposition method and high temperature treatment method all have the problems of complicated process operation, high cost, poor repeatability and unsuitability for mass industrial production.

[0058] The inventors continue to develop the porous carbon material electrode, and try to introduce conductive carbon material into the porous carbon material. The inventors find that a large amount of non-conductive binder needs to be added when preparing the electrode, the resistivity of the electrode is high, and the conductivity is poor. In addition, the conductive carbon material and the porous carbon material belong to different materials, and when preparing the electrode, the porous carbon material will be aggregated in large amounts, and the dispersibility is poor, which cannot meet the use requirements of the capacitive deionization electrode.

[0059] The inventors continue to develop the composition for capacitive deionization electrode, introduce the oxidized modified conductive carbon material and the porous carbon material, the oxidized modified conductive carbon material and the porous carbon material form part of hydrogen bonds, the oxidized modified conductive carbon material and the porous carbon material are connected through the action of the hydrogen bond, the agglomeration of the porous carbon material is avoided; secondly, the oxidized carbon nanotube and / or the oxidized modified carbon fiber and the granular porous carbon material also exist the physical entanglement, so that the oxidized modified conductive carbon material and the porous carbon material are physically entangled together, the amount of the binder used can be reduced when preparing the electrode, the influence of the binder on the conductivity of the electrode is reduced, and the introduction of the oxidized modified conductive carbon material can also reduce the resistivity of the electrode and improve the conductivity.

[0060] In order to further improve the desalination efficiency and adsorption speed, the inventors try to use the electrode made of the oxidized modified conductive carbon material and the oxidized modified activated carbon, which has a high specific surface area, a large pore volume and a large pore size, can make the hydrated ions quickly mass transfer and diffuse, improve the speed of adsorbing the anions and cations in water, and make the maximum adsorption speed of the electrode reach 200-400 mg / (m 2 In addition, the oxidized modified conductive carbon material and the oxidized modified activated carbon both have good hydrophilic properties, which can meet the material performance requirements of the capacitive deionization electrode in the water treatment field.

[0061] In some embodiments of the present application, the present application provides an electrode composition, the electrode composition includes a porous carbon material, an oxidized modified conductive carbon material and a binder, and the mass ratio of the binder, the porous carbon material and the oxidized modified conductive carbon material is 1:(4-96):(0.2-15).

[0062] In some embodiments of the present application, the porous carbon material and the oxidized modified conductive carbon material are connected by hydrogen bonds. The oxidized modified conductive carbon material contains oxygen-containing functional groups, and the surface of the porous carbon material also contains some oxygen-containing functional groups, so the porous carbon material and the oxidized modified conductive carbon material can be connected by hydrogen bonds. There is also physical entanglement between the porous carbon material and the oxidized modified conductive carbon material. Through the action of hydrogen bonds and physical entanglement, the dispersibility of the porous carbon material is improved, and the agglomeration of the granular porous carbon material due to electrostatic action is avoided.

[0063] In some embodiments of the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material is 1:(5-96):(0.2-15), for example: 1:5:0.2, 1:5:5, 1:5:15, 1:6:0.2, 1:6:8, 1:6:15, 1:8:0.8, 1:8:1.2, 1:8:2, 1:8:5, 1:8:15, 1:9:0.8, 1:9:0.9, 1:9:1, 1:9:1.2, 1:10:0.2, 1:10:0.8, 1:10:0.9, 1:10:1, 1:10:1.5, 1:10:2, 1:10:2.5, 1:11:0.8, 1:11:0.9, 1:11:1, 1:11:1.2, 1:11:1.8, 1:11:2, 1:11:2.5, 1:12:0.8, 1:12:1.4, 1:12:1.9, 1:12:2.5, 1:13:0.8, 1:13:0.9, 1:13:1, 1:13:1.2, 1:13:1.8, 1:13:2, 1:13:2.5, 1:14:0.8, 1:14:0.9, 1:14:1, 1:14:1.2, 1:14:1.8, 1:14:2, 1:14:2.5, 1:15:0.2, 1:15:10, 1:15:15, 1:16:0.8, 1:16:0.9, 1:16:1, 1:16:1.2, 1:16:1.8, 1:16:3, 1:16:5, 1:20:0.2, 1:20:6, 1:20:15, 1:30:0.2, 1:30:5, 1:30:15, 1:40:0.2, 1:40:13, 1:50:0.2, 1:50:11, 1:60:0.2, 1:60:15, 1:70:0.2, 1:70:5, 1:70:15, 1:80:5, 1:80:10, 1:90:5, 1:90:15, 1:96:5, 1:96:10, 1:96:15; in some embodiments of the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material is 1:(5-50):(0.5-8); in some embodiments of the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material is 1:(5-35):(0.5-5); in some embodiments of the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material is 1:(10-16):(0.8-2.5).

[0064] In the present application, the mass ratio of the binder, the porous carbon material and the oxidatively modified conductive carbon material needs to meet the above range. Since the binder is generally a non-conductive material, if the amount of the binder used is high, it will affect the conductivity of the electrode composition, and if the amount of the binder used is low, the oxidatively modified conductive carbon material and the porous carbon material are prone to fall off during the preparation of the electrode, affecting the service life and desalination rate of the electrode. If the amount of the oxidatively modified conductive carbon material used is small, the improvement in conductivity is small, and if the amount of the oxidatively modified conductive carbon material used is large, it will affect the desalination effect; if the amount of the porous carbon material used is large, the dispersibility of the porous carbon material is poor and agglomeration occurs, which is not conducive to obtaining an electrode composition with uniform composition; if the amount of the porous carbon material used is small, it will affect the desalination effect.

[0065] In some embodiments of the present application, at least part of the porous carbon material and the oxidatively modified conductive carbon material in the electrode composition are connected by hydrogen bonds. In the electrode composition of the present application, the oxidatively modified conductive carbon material contains oxygen-containing functional groups, and the surface of the porous carbon material also contains some oxygen-containing functional groups. Part of the porous carbon material and the oxygen-containing functional groups in the oxidatively modified conductive carbon material form hydrogen bonds and are connected together by hydrogen bond interaction. The remaining porous carbon material is dispersed by physical mixing such as entanglement, improving the dispersibility of the porous carbon material and avoiding agglomeration of the porous carbon material caused by electrostatic interaction. In the preparation of the electrode, the amount of the binder used can also be reduced, and the influence of the non-conductive binder on the conductivity of the electrode composition is reduced.

[0066] In some embodiments of the present application, the porous carbon material is selected from activated carbon, oxidatively modified activated carbon or a combination thereof; in some embodiments of the present application, the porous carbon material is oxidatively modified activated carbon. When the porous carbon material is activated carbon, there are certain oxygen-containing functional groups on the surface of the activated carbon, which can form a certain amount of hydrogen bonds with the oxidatively modified conductive carbon material. In addition, the specific surface area of the porous carbon material is high (the specific surface area is greater than 1000 m 2 / g), and has a large number of pores (the pore volume is greater than 0.57 cm 3 / g), which can adsorb positive and negative ions in the porous carbon material during desalination. The large specific surface area and large pore volume are both conducive to improving the desalination rate. When the porous carbon material is oxidatively modified activated carbon, the amount of oxygen-containing functional groups in the porous carbon material is high, which can form more hydrogen bonds with the oxidatively modified conductive carbon material. Compared with activated carbon, the use of oxidatively modified activated carbon has better dispersing effect and better effect of reducing the amount of the binder used. In addition, oxidatively modified activated carbon has better hydrophilic effect than activated carbon and is more suitable for use in the field of water treatment.

[0067] In some embodiments of the present application, the oxidized modified activated carbon is prepared by mixing and reacting the activated carbon with an oxidizing agent. In some embodiments of the present application, the oxidizing agent is selected from at least one of concentrated nitric acid, concentrated sulfuric acid, hydrogen peroxide, potassium dichromate, potassium permanganate, and nickel permanganate. The oxidation reaction occurs by placing the activated carbon in a solution of the oxidizing agent, introducing oxygen-containing functional groups such as carboxyl groups and hydroxyl groups into the activated carbon, and the oxidation effect is good and the damage to the activated carbon is small, which can enhance the binding force between the activated carbon and the oxidized modified conductive carbon material, and in addition, the introduction of oxygen-containing functional groups can also improve the hydrophilicity of the activated carbon.

[0068] In some embodiments of the present application, the porous carbon material is oxidized modified activated carbon, and the mass percentage of oxygen in the oxidized modified activated carbon is 1-10%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%. In some embodiments of the present application, the porous carbon material is oxidized modified activated carbon, and the mass percentage of oxygen in the oxidized modified activated carbon is 2-8%. In some embodiments of the present application, the porous carbon material is oxidized modified activated carbon, and the mass percentage of oxygen in the oxidized modified activated carbon is 4-7%. If the oxygen content in the oxidized modified activated carbon is too high (for example, greater than 10%), it will affect the conductivity of the electrode, and if the oxygen content in the oxidized modified activated carbon is too low (for example, less than 1%), the dispersibility of the oxidized modified activated carbon is reduced and the amount of binder used is relatively high.

[0069] In some embodiments of the present application, the water contact angle of the oxidized modified activated carbon is 35-87°. The oxidized modified activated carbon in the present application has excellent hydrophilicity and can be applied to remove positive and negative ions in water.

[0070] In some embodiments of the present application, the mass percentage of oxygen in the oxidized modified conductive carbon material is 1-30%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%. In some embodiments of the present application, the mass percentage of oxygen in the oxidized modified conductive carbon material is 1-15%. In some embodiments of the present application, the mass percentage of oxygen in the oxidized modified conductive carbon material is 1-10%. In some embodiments of the present application, the mass percentage of oxygen in the oxidized modified conductive carbon material is 2-8%. If the oxygen content in the oxidized modified conductive carbon material is too high (for example, greater than 30%), it will affect the conductivity of the electrode, and if the oxygen content in the oxidized modified conductive carbon material is too low (for example, less than 1%), the dispersibility of the oxidized modified activated carbon is reduced and the amount of binder used is relatively high.

[0071] In the present application, the mass percentage of oxygen in the oxidatively modified conductive carbon material can be the same as or different from the mass percentage of oxygen in the oxidatively modified activated carbon. When the mass percentage of oxygen in the oxidatively modified activated carbon is 1-10% and the mass percentage of oxygen in the oxidatively modified conductive carbon material is 1-30%, more hydrogen bonds can be formed between the oxidatively modified conductive carbon material and the oxidatively modified activated carbon, which is conducive to the dispersion of the two and can reduce the amount of binder used. When the mass percentage of oxygen in the oxidatively modified activated carbon is higher, the hydrophilic property is better.

[0072] In some embodiments of the present application, the conductive carbon material is selected from at least one of graphene, carbon nanotubes, conductive carbon black, and carbon fibers. The introduction of the above-mentioned conductive carbon material in the electrode composition of the present application can further improve the conductivity, and the surface of the conductive carbon material is provided with oxygen-containing functional groups through oxidative modification, which can form hydrogen bonds with the porous carbon material, improve the dispersion effect of the porous carbon material, and reduce the amount of binder used.

[0073] In some embodiments of the present application, the oxidatively modified conductive carbon material is prepared by mixing and reacting the conductive carbon material with an oxidizing agent. In some embodiments of the present application, the oxidizing agent is selected from at least one of concentrated nitric acid, concentrated sulfuric acid, hydrogen peroxide, potassium dichromate, potassium permanganate, and nickel permanganate. By placing the conductive carbon material in a solution of the oxidizing agent to undergo oxidation reaction, carboxyl groups, hydroxyl groups, and other oxygen-containing functional groups are introduced into the conductive carbon material, the oxidation effect is good, and the damage to the conductive carbon material is small, which can enhance the bonding force between the conductive carbon material and the porous carbon material.

[0074] In some embodiments of the present application, the electrical conductivity of the oxidatively modified conductive carbon material is 0.21-0.59 Ω·cm. The oxidatively modified conductive carbon material in the present application has relatively high electrical conductivity, which can significantly improve the conductivity when introduced into the electrode composition of the present application.

[0075] In some embodiments of the present application, the aspect ratio of the carbon fibers is 2-30; and in some embodiments of the present application, the aspect ratio of the carbon nanotubes is 2000-10000. The selection of carbon fibers and carbon nanotubes with the above-mentioned aspect ratio is conducive to the physical entanglement between the oxidatively modified conductive carbon material and the porous carbon material, and is conducive to the construction of a connected conductive network, which can improve the dispersion of the porous carbon material while reducing the amount of binder used.

[0076] In some embodiments of the present application, the porous carbon material is in a particulate form; the conductive carbon material is selected from carbon nanotubes, carbon fibers, or a combination thereof. When the porous carbon material is in a particulate form and the conductive carbon material is in a non-particulate form (i.e., in the form of carbon nanotubes, carbon fibers, or a combination thereof), the physical entanglement between the non-particulate conductive carbon material and the particulate porous carbon material is facilitated, and a conductive network is built, which improves the dispersibility of the porous carbon material and reduces the amount of binder used.

[0077] In some embodiments of the present application, the particle size of the porous carbon material is 25-270 μm. The particle size of the porous carbon material is uniform, which is beneficial to the dispersibility of the porous carbon material when the porous carbon material is used in the electrode composition of the present application.

[0078] In some embodiments of the present application, the electrode composition further comprises a solvent. The solvent is used for the dispersion of the binder, the porous carbon material, and the oxidatively modified conductive carbon material, which is beneficial to the processing of the electrode composition into an electrode and improves the processability of the electrode composition.

[0079] In some embodiments of the present application, the mass percentage of the solvent in the electrode composition is 60-95%, for example, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95%. In some embodiments of the present application, the mass percentage of the solvent in the electrode composition is 60-80%. If the amount of the solvent is too large, the solid content of the electrode composition is too low, which is not conducive to the processing of the electrode. If the amount of the solvent is too small, the solid content of the electrode composition is too high, which is not conducive to the preparation of an electrode film with good thickness uniformity.

[0080] In some embodiments of the present application, the solvent is selected from at least one of methanol, ethanol, ethylene glycol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, carbon tetrachloride, N-methylpyrrolidone, and water. In some embodiments of the present application, the solvent is selected from at least one of N-methylpyrrolidone and water. The solvent used in the present application has less environmental pollution, higher safety, lower cost, and is easy to volatilize, which is beneficial to obtaining an electrode film with high thickness uniformity.

[0081] In some embodiments of the present application, the binder is selected from at least one of polyacrylic acid, polyethylene glycol, polyvinyl alcohol, polyamide acid, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, carboxymethyl cellulose, sodium hydroxymethyl cellulose, and styrene butadiene rubber. Compared with other binders in the prior art, the binder in the present application has less influence on the conductivity of the electrode composition when used, and has good compatibility with the porous carbon material and the oxidatively modified conductive carbon material.

[0082] In some embodiments of the present application, the weight average molecular weight of the binder is 5000-2000000, for example, can be: 5000, 7000, 9000, 10000, 12000, 14000, 16000, 18000, 20000, 30000, 40000, 50000, 60000, 70000, 100000, 200000, 300000, 400000, 500000, 600000, 700000, 800000, 900000, 1000000, 1100000, 1200000, 1300000, 1400000, 1500000, 1600000, 1700000, 1800000, 1900000, 2000000. In some embodiments of the present application, the weight average molecular weight of the binder is 8000-1000000. In some embodiments of the present application, the weight average molecular weight of the binder is 8000-120000. When the weight average molecular weight of the binder is too small, for example, less than 5000, the viscosity of the binder is small, and the binder cannot play a role as a binder. When the weight average molecular weight of the binder is too large, for example, greater than 2000000, the viscosity of the binder is too large, which is not conducive to the dispersion of the porous carbon material and the oxidatively modified conductive carbon material, and is even less conducive to the preparation of an electrode film with high thickness uniformity.

[0083] In some embodiments of the present application, the present application also provides a preparation method of the above-mentioned electrode composition, comprising the following steps: mixing the oxidatively modified conductive carbon material, the porous carbon material, the binder, and the optional solvent to obtain the electrode composition.

[0084] The present application uses the oxidatively modified conductive carbon material, the porous carbon material, and the binder as raw materials, which are widely available and low in cost. At the same time, the preparation method of the present application is simple and mild in reaction conditions, and has no requirements for equipment, and can be mass-produced industrially.

[0085] In some embodiments of the present application, the preparation method comprises the following steps:

[0086] S1: mixing the binder with part of the solvent to obtain a binder dispersion liquid; mixing the oxidatively modified conductive carbon material and the porous carbon material with the remaining solvent to obtain a conductive dispersion liquid;

[0087] S2: After mixing the binder dispersion liquid and the conductive dispersion liquid, an electrode composition is prepared.

[0088] In the present application, the binder dispersion liquid and the conductive dispersion liquid are prepared separately and then mixed. This preparation method is beneficial to the mixing and dispersion of the binder, the oxidized and modified conductive carbon material, and the porous carbon material, thereby avoiding the agglomeration of the porous carbon material due to electrostatic interaction.

[0089] In some embodiments of the present application, the mixing step in the preparation method is mixing at 15-40℃, for example, mixing at 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, 36℃, 37℃, 38℃, 39℃, or 40℃. In some embodiments of the present application, the mixing step in the preparation method is mixing at 20-35℃. The present application uses a lower mixing temperature, which can save energy consumption.

[0090] In some embodiments of the present application, the mixing time in the preparation method is 1-10h, for example, the mixing time can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, or 10h. The present application uses a mixing time of 1-10h, which can ensure uniform mixing of the raw materials and good dispersion of the porous carbon material and the oxidized and modified conductive carbon material.

[0091] In some embodiments of the present application, the mixing step is mixing by stirring. The present application uses stirring for mixing, which has lower requirements for equipment and can reduce production costs.

[0092] In some embodiments of the present application, the stirring rate is 100-10000rpm, for example, it can be 100rpm, 200rpm, 400rpm, 500rpm, 600rpm, 800rpm, 1000rpm, 1200rpm, 1400rpm, 1600rpm, 1800rpm, 2000rpm, 3000rpm, 4000rpm, 5000rpm, 6000rpm, 7000rpm, 8000rpm, 9000rpm, or 10000rpm. In some embodiments of the present application, the stirring rate is 500-5000rpm. In some embodiments of the present application, the stirring rate is 500-2000rpm. Stirring at a stirring rate of 100-10000rpm can fully disperse the porous carbon material and the oxidized and modified conductive carbon material.

[0093] In some embodiments of the present application, the step S2 specifically comprises: mixing the binder dispersion liquid and the conductive dispersion liquid, and then sieving to obtain the electrode composition. The sieving step can avoid the electrode composition containing large particles, thereby affecting the subsequent use, and is beneficial to obtaining an electrode film with good thickness and composition uniformity.

[0094] In some embodiments of the present application, the sieving step is performed by using a sieve with a mesh size of 50-500. If the mesh size of the sieve is too small, the particles in the electrode composition are too small, which is not conducive to the construction of the conductive network and affects the conductivity of the electrode composition. If the mesh size of the sieve is too large, the electrode composition contains large particles of raw materials, which is not conducive to obtaining an electrode film with good thickness and composition uniformity.

[0095] In some embodiments of the present application, the present application further provides a capacitive deionization electrode comprising an electrode layer; the preparation raw material of the electrode layer is the electrode composition described above.

[0096] The capacitive deionization electrode in the present application has a high desalination rate, a large specific surface area, a high pore volume, a low resistivity, a good service life and a good use stability; can realize rapid and efficient removal of anions and cations in water, and has a good application prospect in the field of capacitive deionization water treatment.

[0097] In some embodiments of the present application, the maximum adsorption speed of the anions and cations of the capacitive deionization electrode is 200-400 mg / (m 2 ·min), for example, can be: 200 mg / (m 2 ·min), 210 mg / (m 2 ·min), 220 mg / (m 2 ·min), 230 mg / (m 2 ·min), 240 mg / (m 2 ·min), 250 mg / (m 2 ·min), 260 mg / (m 2 ·min), 270 mg / (m 2 ·min), 280 mg / (m 2 ·min), 290 mg / (m 2 ·min), 300 mg / (m 2 ·min), 310 mg / (m 2 ·min), 320 mg / (m 2 ·min), 330 mg / (m 2 ·min), 340 mg / (m 2 ·min), 350 mg / (m 2 ·min), 360 mg / (m 2• min), 370 mg / (m 2 • min), 380 mg / (m 2 • min), 390 mg / (m 2 • min), 400 mg / (m 2 • min); in some embodiments of the present application, the maximum adsorption rate of the anions and cations of the capacitive deionization electrode is 240-350 mg / (m 2 • min); in some embodiments of the present application, the maximum adsorption rate of the anions and cations of the capacitive deionization electrode is 240-330 mg / (m 2 • min). The capacitive deionization electrode in the present application has a large adsorption rate, which is conducive to faster adsorption and removal of various positive and negative ions in water.

[0098] In some embodiments of the present application, the specific surface area of the capacitive deionization electrode is 700-2500 m 2 / g, for example, can be: 700 m 2 / g, 800 m 2 / g, 900 m 2 / g, 1000 m 2 / g, 1100 m 2 / g, 1200 m 2 / g, 1300 m 2 / g, 1400 m 2 / g, 1500 m 2 / g, 1600 m 2 / g, 1700 m 2 / g, 1800 m 2 / g, 1900 m 2 / g, 2000 m 2 / g, 2100 m 2 / g, 2200 m 2 / g, 2300 m 2 / g, 2400 m 2 / g, 2500 m 2 / g. In some embodiments of the present application, the specific surface area of the capacitive deionization electrode is 900-2200 m 2 / g; in some embodiments of the present application, the specific surface area of the capacitive deionization electrode is 900-1800 m 2 / g; in some embodiments of the present application, the specific surface area of the capacitive deionization electrode is 900-1200 m 2 / g. The capacitive deionization electrode in the present application has a large specific surface area, which is conducive to obtaining a high desalination rate.

[0099] In some embodiments of the present application, the pore volume of the capacitive deionization electrode is 0.8-1.1 cm3 / g, for example, it can be 0.8 cm3 / g, 0.85 cm3 / g, 0.9 cm3 / g, 0.95 cm3 / g, 1.0 cm3 / g, 1.05 cm3 / g, 1.1 cm3 / g. 3 / g, for example, it can be 0.8 cm3 / g, 0.85 cm3 / g, 0.9 cm3 / g, 0.95 cm3 / g, 1.0 cm3 / g, 1.05 cm3 / g, 1.1 cm3 / g. 3 / g, 0.85 cm3 / g, 0.9 cm3 / g, 0.95 cm3 / g, 1.0 cm3 / g, 1.05 cm3 / g, 1.1 cm3 / g. 3 / g, 0.85 cm3 / g, 0.9 cm3 / g, 0.95 cm3 / g, 1.0 cm3 / g, 1.05 cm3 / g, 1.1 cm3 / g. 3 / g, 0.85 cm3 / g, 0.9 cm3 / g, 0.95 cm3 / g, 1.0 cm3 / g, 1.05 cm3 / g, 1.1 cm3 / g. 3 / g, 0.85 cm3 / g, 0.9 cm3 / g, 0.95 cm3 / g, 1.0 cm3 / g, 1.05 cm3 / g, 1.1 cm3 / g. 3 / g, 0.85 cm3 / g, 0.9 cm3 / g, 0.95 cm3 / g, 1.0 cm3 / g, 1.05 cm3 / g, 1.1 cm3 / g. 3 / g, 0.85 cm3 / g, 0.9 cm3 / g, 0.95 cm3 / g, 1.0 cm3 / g, 1.05 cm3 / g, 1.1 cm3 / g. 3 / g; the capacitive deionization electrode in the present application has a proper pore volume, which is beneficial to the adsorption and deintercalation of positive and negative ions in water.

[0100] In some embodiments of the present application, the resistivity of the capacitive deionization electrode is 0.3-0.7 Ω·cm, for example, it can be 0.3 Ω·cm, 0.35 Ω·cm, 0.4 Ω·cm, 0.45 Ω·cm, 0.5 Ω·cm, 0.55 Ω·cm, 0.6 Ω·cm, 0.65 Ω·cm, 0.7 Ω·cm. The capacitive deionization electrode in the present application has a low resistivity and excellent conductivity.

[0101] In some embodiments of the present application, the desalination rate of the capacitive deionization electrode is not less than 60% when the working voltage is 1.5-2 V, for example, the desalination rate can be 61%, 63%, 65%, 67%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, 98%, 100%. The capacitive deionization electrode in the present application has a high desalination rate in a wide voltage range.

[0102] In some embodiments of the present application, the capacitive deionization electrode has a microporous structure. The capacitive deionization electrode in the present application has a large number of microporous structures, which can make the positive and negative ions in water adsorbed in the micropores of the capacitive deionization electrode.

[0103] In some embodiments of the present application, the present application further provides a water treatment device comprising the above capacitive deionization electrode.

[0104] In some embodiments of the present application, the water treatment device comprises a purified water device, a water desalination device, and a water quality softening device.

[0105] In some embodiments of the present application, the water treatment device comprises two oppositely arranged capacitive deionization electrodes.

[0106] The water treatment device in the application is installed with the above-mentioned capacitive deionization electrode. In operation, a direct current external voltage is applied to the capacitive deionization electrode, so as to form an electrostatic field between the two capacitive deionization electrodes, so that the positive and negative ions in the water are oriented to move to the surface of the capacitive deionization electrode with opposite charge, and are stored on the surface of the capacitive deionization electrode, so as to reduce the salt concentration in the solution, thereby achieving the purpose of deionization. The power supply is reversed or no voltage is applied, so as to discharge the capacitive deionization electrode, and the ions adsorbed on the surface of the capacitive deionization electrode are released into the solution again, and the capacitive deionization electrode is regenerated. The water treatment device in the application has the advantages of low energy consumption, no secondary pollution, green environmental protection, etc., and has high desalination rate and desalination rate.

[0107] In some embodiments of the application, the above-mentioned electrode composition can be used in the field of water treatment.

[0108] In some embodiments of the application, the above-mentioned capacitive deionization electrode can be applied to the field of water treatment.

[0109] The embodiments of the application are further illustrated in detail in combination with specific examples:

[0110] The specific preparation method of the oxidized carbon nanotube used in the embodiments of the application is as follows: carbon nanotubes and nitric acid solution (the concentration of nitric acid is 12 mol / L) are placed in a three-necked flask for reaction at a temperature of 80℃, and then the oxidized carbon nanotubes are washed with pure water until the pH value is neutral, and are dried to obtain the product. By changing the ratio of the amount of carbon nanotubes to the amount of nitric acid and the reaction time, carbon nanotubes with different oxygen contents can be prepared.

[0111] The oxidized modified activated carbon used in the embodiments of the application has good hydrophilicity after oxidation modification. The preparation method of the oxidized carbon nanotube can be used to oxidize the activated carbon with an oxidizing agent to obtain the product.

[0112] Example 1

[0113] The example provides an electrode composition prepared by the following preparation method. The preparation steps include:

[0114] Polyvinylidene fluoride and N-methyl pyrrolidone are mixed in a mass ratio of 1:20, and are dispersed by a homogenizer at 25℃ for 3 hours with a stirring speed of 1000 rpm to obtain a dispersion liquid of the binder material, wherein the weight average molecular weight of the polyvinylidene fluoride is 110000.

[0115] The oxidized carbon nanotube (i.e., the electrically conductive carbon material modified by oxidation), the activated carbon modified by oxidation (i.e., the porous carbon material), and N-methylpyrrolidone are mixed in a ratio of 1:10:20 by mass, and stirred for 3 hours at 25°C by a homogenizer at a stirring speed of 1000 rpm. Then, the mixture is stirred for 5 hours at 1000 rpm after being mixed with the dispersion liquid of the binder material described above. The mixed slurry is filtered through a stainless steel screen having a mesh size of 200, to obtain the electrode composition of this example.

[0116] The mass percentage of the solids (the solids refer to the polyvinylidene fluoride, the oxidized carbon nanotube, and the activated carbon modified by oxidation) in the electrode composition of this example is 25%, wherein the mass percentage of the polyvinylidene fluoride is 6.3%, the mass percentage of the oxidized carbon nanotube is 8.5%, and the mass percentage of the activated carbon modified by oxidation is 85.2%, based on the total mass percentage of the solids in the electrode composition being 100%. The mass percentage of oxygen in the oxidized carbon nanotube is 10%, and the mass percentage of oxygen in the activated carbon modified by oxidation is 2%.

[0117] Example 2

[0118] This example provides an electrode composition prepared by the following preparation method, and the preparation steps include:

[0119] The sodium hydroxymethyl cellulose and water are mixed in a ratio of 1:20 by mass, and dispersed and stirred for 3 hours at 25°C by a homogenizer at a stirring speed of 1000 rpm, to obtain the dispersion liquid of the binder material, wherein the weight average molecular weight of the sodium hydroxymethyl cellulose is 80000.

[0120] The oxidized carbon nanotube, the activated carbon modified by oxidation, and water are mixed in a ratio of 1:10:20 by mass, and stirred for 5 hours at 25°C by a homogenizer at a stirring speed of 1000 rpm. Then, the mixture is stirred for 10 hours at 1000 rpm after being mixed with the dispersion liquid of the binder material described above. The mixed slurry is filtered through a stainless steel screen having a mesh size of 200, to obtain the electrode composition of this example.

[0121] The mass percentage of the solids (the solids refer to the sodium hydroxymethyl cellulose, the oxidized carbon nanotube, and the activated carbon modified by oxidation) in the electrode composition of this example is 25%, wherein the mass percentage of the sodium hydroxymethyl cellulose is 6.3%, the mass percentage of the oxidized carbon nanotube is 8.5%, and the mass percentage of the activated carbon modified by oxidation is 85.2%, based on the total mass percentage of the solids in the electrode composition being 100%. The mass percentage of oxygen in the oxidized carbon nanotube is 10%, and the mass percentage of oxygen in the activated carbon modified by oxidation is 2%.

[0122] Example 3

[0123] The example provides an electrode composition prepared by the following preparation method, and the preparation steps include:

[0124] Polyvinylidene fluoride and N-methyl pyrrolidone were mixed in a mass ratio of 1:20, and dispersed by a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm to obtain a dispersion liquid of the binder material, wherein the weight average molecular weight of the polyvinylidene fluoride was 110000.

[0125] Graphene oxide, oxidized modified activated carbon and N-methyl pyrrolidone were mixed in a mass ratio of 1:10:20, and stirred by a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm; then mixed with the above-mentioned dispersion liquid of the binder material and continued to stir for 5 hours at a stirring speed of 1000 rpm; and the mixed slurry was filtered through a stainless steel screen with a mesh size of 200 to obtain the electrode composition in the example.

[0126] The mass percentage of solids (the solids refer to polyvinylidene fluoride, graphene oxide and oxidized modified activated carbon) in the electrode composition in the example was 25%, wherein, based on the total mass percentage of the solids in the electrode composition being 100%, the mass percentage of polyvinylidene fluoride was 6.3%, the mass percentage of graphene oxide was 8.5%, and the mass percentage of oxidized modified activated carbon was 85.2%. Among them, the mass percentage of oxygen in graphene oxide was 1%, and the mass percentage of oxygen in oxidized modified activated carbon was 8%.

[0127] Example 4

[0128] The example provides an electrode composition prepared by the following preparation method, and the preparation steps include:

[0129] Sodium hydroxymethyl cellulose and water were mixed in a mass ratio of 1:20, and dispersed by a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm to obtain a dispersion liquid of the binder material, wherein the weight average molecular weight of the sodium hydroxymethyl cellulose was 80000.

[0130] Oxidized conductive carbon black (which is oxidized by using a modified Hamer method, in which the oxidizing agent is concentrated sulfuric acid with a mass fraction of 98% and potassium permanganate), oxidized modified activated carbon and water were mixed in a mass ratio of 1:10:20, and stirred by a homogenizer at 25°C for 5 hours at a stirring speed of 1000 rpm; then mixed with the above-mentioned dispersion liquid of the binder material and continued to stir for 10 hours at a stirring speed of 1000 rpm; and the mixed slurry was filtered through a stainless steel screen with a mesh size of 200 to obtain the electrode composition in the example.

[0131] The mass percentage of solids (solids refer to sodium hydroxymethyl cellulose, oxidized conductive carbon black and oxidized modified activated carbon) in the electrode composition in this example is 25%, wherein the mass percentage of sodium hydroxymethyl cellulose is 6.3%, the mass percentage of oxidized conductive carbon black is 8.5%, and the mass percentage of oxidized modified activated carbon is 85.2% based on the total mass percentage of solids in the electrode composition being 100%. The mass percentage of oxygen in the oxidized conductive carbon black is 10%; the mass percentage of oxygen in the oxidized modified activated carbon is 2%.

[0132] Example 5

[0133] This example provides an electrode composition prepared by the following preparation method, and the preparation steps include:

[0134] Polyacrylonitrile and acetonitrile are mixed in a mass ratio of 1:20, and are dispersed by a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm to obtain a dispersion liquid of the binder material, wherein the weight average molecular weight of the polyacrylonitrile is 2000000.

[0135] Oxidized carbon nanotubes (i.e. oxidized modified conductive carbon material), oxidized modified activated carbon (i.e. porous carbon material) and acetonitrile are mixed in a mass ratio of 1:7.5:10, and are dispersed by a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm; then mixed with the above-mentioned dispersion liquid of the binder material and continue to stir for 5 hours at a stirring speed of 1000 rpm; the mixed slurry is filtered through a stainless steel screen with a mesh size of 200 to obtain the electrode composition in this example.

[0136] The mass percentage of solids (solids refer to polyacrylonitrile, oxidized carbon nanotubes and oxidized modified activated carbon) in the electrode composition in this example is 31%, wherein the mass percentage of polyacrylonitrile is 5.5%, the mass percentage of oxidized carbon nanotubes is 11.2%, and the mass percentage of oxidized modified activated carbon is 83.3% based on the total mass percentage of solids in the electrode composition being 100%. The mass percentage of oxygen in the oxidized carbon nanotubes is 1%, and the mass percentage of oxygen in the oxidized modified activated carbon is 8%.

[0137] Example 6

[0138] This example provides an electrode composition prepared by the following preparation method, and the preparation steps include:

[0139] Polyacrylonitrile and acetonitrile are mixed in a mass ratio of 1:7, and are dispersed by a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm to obtain a dispersion liquid of the binder material, wherein the weight average molecular weight of the polyacrylonitrile is 2000000.

[0140] The oxidized carbon nanotube (i.e., the oxidized modified conductive carbon material), the oxidized modified activated carbon (i.e., the porous carbon material), and the acetonitrile are mixed in a mass ratio of 1:7.5:10, and stirred for 3 hours at 25°C by a homogenizer at a stirring speed of 1000 rpm; then mixed with the dispersion liquid of the binder material as described above and stirred for 5 hours at a stirring speed of 1000 rpm; and the mixed slurry is filtered through a stainless steel screen with a mesh size of 200, to obtain the electrode composition in this example.

[0141] The mass percentage of the solids (the solids refer to the polyacrylonitrile, the oxidized carbon nanotube, and the oxidized modified activated carbon) in the electrode composition in this example is 40%, wherein the mass percentage of the polyacrylonitrile is 5.5%, the mass percentage of the oxidized carbon nanotube is 11.2%, and the mass percentage of the oxidized modified activated carbon is 83.3%, based on the total mass percentage of the solids in the electrode composition being 100%. The mass percentage of oxygen in the oxidized carbon nanotube is 10%, and the mass percentage of oxygen in the oxidized modified activated carbon is 8%.

[0142] Example 7

[0143] This example provides an electrode composition prepared by the following preparation method, and the preparation steps include:

[0144] The polyacrylonitrile and the acetonitrile are mixed in a mass ratio of 1:32, and dispersed and stirred for 3 hours at 25°C by a homogenizer at a stirring speed of 1000 rpm, to obtain the dispersion liquid of the binder material, wherein the weight average molecular weight of the polyacrylonitrile is 2000000.

[0145] The oxidized carbon nanotube (i.e., the oxidized modified conductive carbon material), the oxidized modified activated carbon (i.e., the porous carbon material), and the acetonitrile are mixed in a mass ratio of 1:7.5:10, and stirred for 3 hours at 25°C by a homogenizer at a stirring speed of 1000 rpm; then mixed with the dispersion liquid of the binder material as described above and stirred for 5 hours at a stirring speed of 1000 rpm; and the mixed slurry is filtered through a stainless steel screen with a mesh size of 200, to obtain the electrode composition in this example.

[0146] The mass percentage of the solids (the solids refer to the polyacrylonitrile, the oxidized carbon nanotube, and the oxidized modified activated carbon) in the electrode composition in this example is 40%, wherein the mass percentage of the polyacrylonitrile is 5.5%, the mass percentage of the oxidized carbon nanotube is 11.2%, and the mass percentage of the oxidized modified activated carbon is 83.3%, based on the total mass percentage of the solids in the electrode composition being 100%. The mass percentage of oxygen in the oxidized carbon nanotube is 10%, and the mass percentage of oxygen in the oxidized modified activated carbon is 8%.

[0147] Example 8

[0148] The capacitive deionization electrode of this example was prepared using the following method, the preparation steps of which included:

[0149] The capacitive deionization electrode of this example was prepared using the following method, the preparation steps of which included:

[0150] The electrode composition of Example 1 was coated onto a titanium foil and dried to produce the capacitive deionization electrode of this example.

[0151] Example 9

[0152] The capacitive deionization electrode of this example was prepared using the following method, the preparation steps of which included:

[0153] The capacitive deionization electrode of this example was prepared using the following method, the preparation steps of which included:

[0154] The electrode composition of Example 2 was coated onto a titanium foil and dried to produce the capacitive deionization electrode of this example.

[0155] Example 10

[0156] The capacitive deionization electrode of this example was prepared using the following method, the preparation steps of which included:

[0157] The capacitive deionization electrode of this example was prepared using the following method, the preparation steps of which included:

[0158] The electrode composition of Example 3 was coated onto a titanium foil and dried to produce the capacitive deionization electrode of this example.

[0159] Example 11

[0160] The capacitive deionization electrode of this example was prepared using the following method, the preparation steps of which included:

[0161] The capacitive deionization electrode of this example was prepared using the following method, the preparation steps of which included:

[0162] The electrode composition of Example 4 was coated onto a titanium foil and dried to produce the capacitive deionization electrode of this example.

[0163] Example 12

[0164] The capacitive deionization electrode of this example includes a substrate and an electrode layer attached to the substrate, the electrode layer being made using the electrode composition of Example 5.

[0165] The capacitive deionization electrode of this example is made using the following preparation method, the preparation steps including:

[0166] The electrode composition of Example 5 is coated on a titanium foil, dried, to make the capacitive deionization electrode of this example.

[0167] Example 13

[0168] The capacitive deionization electrode of this example includes a substrate and an electrode layer attached to the substrate, the electrode layer being made using the electrode composition of Example 6.

[0169] The capacitive deionization electrode of this example is made using the following preparation method, the preparation steps including:

[0170] The electrode composition of Example 6 is coated on a titanium foil, dried, to make the capacitive deionization electrode of this example.

[0171] Example 14

[0172] The capacitive deionization electrode of this example includes a substrate and an electrode layer attached to the substrate, the electrode layer being made using the electrode composition of Example 7.

[0173] The capacitive deionization electrode of this example is made using the following preparation method, the preparation steps including:

[0174] The electrode composition of Example 7 is coated on a titanium foil, dried, to make the capacitive deionization electrode of this example.

[0175] Example 15

[0176] The water purifier of this example has electrodes made using the capacitive deionization electrode of Example 8.

[0177] Example 16

[0178] The water purifier of this example has electrodes made using the capacitive deionization electrode of Example 9.

[0179] Example 17

[0180] The water purifier of this example has electrodes made using the capacitive deionization electrode of Example 10.

[0181] Example 18

[0182] The example provides a water purifier, and the electrode of the water purifier in the example is the capacitive deionization electrode in the example 11.

[0183] Example 19

[0184] The example provides a water purifier, and the electrode of the water purifier in the example is the capacitive deionization electrode in the example 12.

[0185] Example 20

[0186] The example provides a water purifier, and the electrode of the water purifier in the example is the capacitive deionization electrode in the example 13.

[0187] Example 21

[0188] The example provides a water purifier, and the electrode of the water purifier in the example is the capacitive deionization electrode in the example 14.

[0189] Performance test:

[0190] (1) Surface morphology test

[0191] The surface morphology of the capacitive deionization electrode in the example 8 is tested by a scanning electron microscope, and the specific test method is shown in FIG. 1. As shown in FIG. 1, the capacitive deionization electrode in the example 8 has a loose and porous surface morphology, and the pore size distribution is mainly micron level, which has no limiting effect on the mass transfer and diffusion of hydrated ions. The hydrated ions can quickly and efficiently pass through the pore size of the surface of the capacitive deionization electrode, and then be adsorbed inside the capacitive deionization electrode to realize desalination. In addition, it can be seen from FIG. 1 that the oxidized activated carbon and the oxidized carbon nanotube are intertwined together, and the oxidized activated carbon is uniformly dispersed without agglomeration. The reason is that the oxidized activated carbon and the oxidized carbon nanotube are both distributed with oxygen-containing functional groups on the surface, and hydrogen bonds are formed between the oxygen-containing functional groups, so that the oxidized activated carbon and the oxidized carbon nanotube are connected. In addition, the oxidized carbon nanotube and the oxidized activated carbon can also be connected by physical entanglement. Through chemical and physical entanglement, the oxidized activated carbon can be uniformly dispersed, avoiding the agglomeration of the granular oxidized activated carbon due to electrostatic effect, and affecting the uniformity of the surface composition of the capacitive deionization electrode and the conductivity.

[0192] (2) TDS test

[0193] The capacitive deionization electrode in Example 8 was placed in a NaCl solution with a flow rate of 200 mL / min and a concentration of 200 mg / L, and then a working voltage of 1.5 V was applied to perform a desalination performance test, wherein the calculation formula of the desalination rate was: desalination rate % = (inlet water concentration-outlet water concentration) / original inlet water concentration x 100%, and the calculation formula of the adsorption rate was: adsorption rate = (desalination rate x inlet water concentration x flow rate) / electrode area. The desalination performance test TDS and voltage relationship curve of the capacitive deionization electrode in Example 8 is shown in FIG. 2. As shown in FIG. 2, the desalination rate of the capacitive deionization electrode in Example 8 reached 86.1% after 2 min, and the maximum adsorption rate was 323 mg / (m 2 ·min).

[0194] The capacitive deionization electrode in Example 9 was placed in a NaCl solution with a flow rate of 200 mL / min and a concentration of 200 mg / L, and then a working voltage of 2 V was applied to perform a desalination performance test, wherein the calculation formula of the desalination rate was: desalination rate % = (inlet water concentration-outlet water concentration) / original inlet water concentration x 100%, and the calculation formula of the adsorption rate was: adsorption rate = (desalination rate x inlet water concentration x flow rate) / electrode area. The desalination performance test TDS and voltage relationship curve of the capacitive deionization electrode in Example 9 is shown in FIG. 3. As shown in FIG. 3, the desalination rate of the capacitive deionization electrode in Example 9 reached 64.5% after 5 min, and the maximum adsorption rate was 241 mg / (m 2 ·min).

[0195] (2) Specific surface area, pore volume and resistivity test

[0196] The specific surface area and pore volume (i.e. pore volume) of the capacitive deionization electrode in Example 8 and Example 9 were tested according to the test method recorded in GB / T 19587-2017 “Gas adsorption BET method for determining the specific surface area of solid substances”, and then the four-probe method was used to test the AC impedance test data of the capacitive deionization electrode in Example 8 and Example 9. The specific test results are shown in Table 1.

[0197] Table 1: Specific surface area, pore volume and resistivity test results

[0198] As shown in Table 1, the capacitive deionization electrode in Examples 8-9 of the present application has a large specific surface area (987-1106 m 2 / g), a high pore volume (0.84-1.06 cm 3 / g) and a small resistivity (0.32-0.64 Ω·cm), which can meet the use requirements of the capacitive deionization electrode.

[0199] It is found through tests that the capacitive deionization electrodes in Examples 10-14 have performances substantially equivalent to those of Examples 8 and 9.

[0200] In summary, the present application can improve the overall conductivity of the capacitive deionization electrode by introducing the oxidized modified conductive carbon material with excellent conductivity into the oxidized modified activated carbon, so that the resistivity of the capacitive deionization electrode is reduced to 0.3-0.7 Ω·cm, the charge can be quickly transferred in the electrode, and the desalination rate of the electrode is improved.

[0201] In addition, the oxidized modified conductive carbon material is connected with the oxidized modified activated carbon through hydrogen bonding and physical entanglement, so as to avoid the agglomeration of the oxidized modified activated carbon due to electrostatic effect, improve the dispersibility of the oxidized modified activated carbon, and reduce the amount of the binder used in the preparation of the electrode to a certain extent, so that the amount of the binder used is not more than 10%. The binder is generally a non-conductive material, and if the amount of the binder used is high, the conductivity of the electrode will be affected. If the amount of the binder used is small, the oxidized modified conductive carbon material and the porous carbon material will be easily detached during the preparation of the electrode, which will affect the service life and desalination rate of the electrode. The physical and chemical entanglement between the oxidized modified activated carbon and the oxidized modified conductive carbon material in the present application will not cause the detachment of the oxidized modified conductive carbon material and the porous carbon material under the premise of reducing the amount of the binder used.

[0202] The capacitive deionization electrode in the present application has a micrometer-level pore size, no limitation on the mass transfer and diffusion of hydrated ions, and has a large specific surface area (700-2500 m 2 / g), a large pore volume (0.8-1.1 cm 3 / g), a large contact area with salt during desalination, improved desalination rate and desalination effect, a maximum adsorption speed of anions and cations of 240-330 mg / (m 2 ·min), and a desalination rate of not less than 60% at a working voltage of 1.5-2 V.

[0203] The above describes the embodiments of the present application in detail, but the present application is not limited to the above-described embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

An electrode composition comprising a porous carbon material, an oxidatively modified conductive carbon material, and a binder, wherein the mass ratio of the binder, the porous carbon material, and the oxidatively modified conductive carbon material is 1:(4-96):(0.2-15). The electrode composition according to claim 1, wherein the mass ratio of the binder, the porous carbon material, and the oxidatively modified conductive carbon material is 1:(10-16):(0.8-2.5). The electrode composition according to claim 1 or 2, wherein at least part of the porous carbon material and the oxidatively modified conductive carbon material in the electrode composition are connected by hydrogen bonds and / or physical entanglement. The electrode composition according to any one of claims 1-3, wherein the porous carbon material is selected from activated carbon, oxidatively modified activated carbon, or a combination thereof. The electrode composition according to any one of claims 1-4, wherein the porous carbon material is oxidatively modified activated carbon, and the mass percentage of oxygen in the oxidatively modified activated carbon is 1-10%. The electrode composition according to any one of claims 1-5, wherein the mass percentage of oxygen in the oxidatively modified conductive carbon material is 1-30%. The electrode composition according to any one of claims 1-6, wherein the conductive carbon material is selected from at least one of graphene, carbon nanotubes, conductive carbon black, and carbon fibers. The electrode composition according to any one of claims 1-7, wherein the porous carbon material is in the form of particles, and the conductive carbon material is selected from carbon nanotubes, carbon fibers, or a combination thereof. The electrode composition according to any one of claims 1-8, further comprising a solvent, wherein the mass percentage of the solvent is 60-95% based on 100% of the mass percentage of the electrode composition. The electrode composition according to claim 9, wherein the solvent is selected from at least one of methanol, ethanol, ethylene glycol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide carbon tetrachloride, N-methylpyrrolidone, and water. The electrode composition according to any one of claims 1-10, wherein the binder is selected from at least one of polyacrylic acid, polyethylene glycol, polyvinyl alcohol, polyamide acid, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, carboxymethyl cellulose, sodium hydroxymethyl cellulose, and styrene butadiene rubber. The electrode composition according to any one of claims 1-11, wherein the weight average molecular weight of the binder is 5000-2000000. A method of preparing the composition for an electrode according to any one of claims 1 to 12, comprising: The electrode composition is prepared by mixing the oxidatively modified conductive carbon material, the porous carbon material, the binder, and optionally the solvent. The preparation method of the electrode composition according to claim 13, further comprising the following steps: S1: mixing the binder with part of the solvent to obtain a binder dispersion liquid; mixing the oxidatively modified conductive carbon material and the porous carbon material with the remaining solvent to obtain a conductive dispersion liquid; and S2: mixing the binder dispersion liquid and the conductive dispersion liquid to obtain the electrode composition. ​ A capacitive deionization electrode comprising an electrode layer, wherein the electrode layer is prepared from the electrode composition according to any one of claims 1 to 12. The capacitive deionization electrode according to claim 15, having at least one of the following features: (a) the maximum adsorption speed of the anion-cation is 200-400 mg / (m 2 ·min); (b) a specific surface area of 700 to 2500 m 2 / g; (c) a pore volume of 0.8 to 1.1 cm3 / g 3 / g; (d) the resistivity is 0.3 to 0.7 Ω·cm; (e) the desalination rate is not less than 60% at a working voltage of 1.5 to 2 V. A water treatment device comprising the capacitive deionization electrode according to any one of claims 15 to 16. The water treatment device according to claim 17, comprising a purified water device, a water desalination device, a water quality softening device. Use of the electrode composition according to any one of claims 1 to 12 and / or the capacitive deionization electrode according to any one of claims 15 to 16 in the field of water treatment.

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