Composition for electrode, capacitive deionization electrode and application

Abstract

The invention relates to a composition for an electrode, a capacitive deionization electrode and application, the composition for the 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). The oxidation modified conductive carbon material with excellent conductivity is introduced into the porous carbon material, so that charges can be quickly transferred in the composition for the electrode, and the desalting rate of the capacitive deionization electrode prepared from the composition for the electrode is further improved. The oxidation-modified conductive carbon material and the porous carbon material are connected through interaction and / or physical winding between functional groups, so that the dispersity of the porous carbon material is improved, the agglomeration of the porous carbon material is avoided, the use amount of a binder is further reduced, and the conductivity of the capacitive deionization electrode is improved.

Description

Technical Field

[0001] The present invention relates to the field of water treatment, and particularly to a composition for an electrode, a capacitive deionization electrode and an application thereof. Background Art

[0002] Capacitive deionization technology usually uses a capacitor as the core component of a deionization device. When water flows through the capacitor, the electric field on the electrode will separate ions with different charges in the water. This technology can remove various ions in the water, including cations and anions such as 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 broad application prospects in the field of water treatment (including seawater and brackish water desalination, lithium extraction from salt lakes, drinking water purification, water softening, etc.).

[0003] The capacitor in capacitive deionization technology is also called a supercapacitor. The specific surface area and charge storage method of a supercapacitor are different from those of an ordinary capacitor. Compared with an ordinary capacitor whose capacity is usually only a few microfarads or millifarads, the capacity of a supercapacitor can reach hundreds or even thousands of farads.

[0004] The key core of capacitive deionization technology lies in the electrode material of the supercapacitor. At present, activated carbon shows good deionization performance in capacitive deionization technology, but there are the following problems in the commercial application process of activated carbon: (1) Although the specific surface area of activated carbon is large, its pore size distribution is mainly micropores (<2 nm), which has a certain limiting effect on the mass transfer and diffusion of hydrated ions. At the same time, due to the poor hydrophilicity of activated carbon itself, its application in capacitive deionization is limited; (2) The conductivity of activated carbon itself is not high, and the resistance is relatively high. In the process of preparing the electrode, a polymer binder with poor conductivity needs to be added. Therefore, the conductivity of activated carbon-based electrode materials is generally poor. Summary of the Invention

[0005] The present invention aims to at least solve one of the above technical problems existing in the prior art. For this reason, one of the purposes of the present invention is to provide a composition for an electrode.

[0006] Another purpose of the present invention is to provide a preparation method of the above composition for an electrode.

[0007] Another purpose of the present invention is to provide a capacitive deionization electrode.

[0008] Another purpose of the present invention is to provide a water treatment device.

[0009] Another purpose of the present invention is to provide an application of the above composition for an electrode and / or capacitive deionization electrode in the field of water treatment.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] A first aspect of the present invention provides a composition for an electrode, the composition for an electrode comprising a porous carbon material, an oxidized conductive carbon material, and a binder, and the mass ratio of the binder, the porous carbon material, and the oxidized conductive carbon material is 1:(4 - 96):(0.2 - 15).

[0012] The technical solution of the present invention regarding the composition for an electrode has at least the following beneficial effects: Introducing an oxidized conductive carbon material with excellent conductivity into the porous carbon material can improve the overall conductivity of the composition for an electrode, and charges can be quickly transferred in the electrode prepared from the composition for an electrode, thereby improving the desalination rate of the electrode. The oxidized conductive carbon material makes the conductive carbon material contain oxygen-containing functional groups, which can be connected to the porous carbon material through the interaction between functional groups and / or physical entanglement, improving the dispersibility of the porous carbon material and avoiding the agglomeration phenomenon of the porous carbon material caused by electrostatic action. When preparing 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 composition for an electrode can be reduced.

[0013] According to some embodiments of the present invention, the mass ratio of the binder, the porous carbon material, and the oxidation-modified conductive carbon material is 1:(5 - 96):(0.2 - 15). For example, it can be 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 invention, the mass ratio of the binder, the porous carbon material, and the oxidation-modified conductive carbon material is 1:(5 - 50):(0.5 - 8); According to some embodiments of the present invention, the mass ratio of the binder, the porous carbon material, and the oxidation-modified conductive carbon material is 1:(5 - 35):(0.5 - 5); According to some embodiments of the present invention, the mass ratio of the binder, the porous carbon material, and the oxidation-modified conductive carbon material is 1:(10 - 16):(0.8 - 2.5).

[0014] In the present invention, the mass ratios of the binder, the porous carbon material, and the oxidation-modified conductive carbon material need to meet the above ranges. 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. If the amount of the binder used is low, the oxidation-modified conductive carbon material and the porous carbon material are likely to fall off during the preparation of the electrode, affecting the service life and desalination rate of the electrode. If the amount of the oxidation-modified conductive carbon material used is low, the improvement in conductivity is small. If the amount of the oxidation-modified conductive carbon material used is high, it will affect the desalination effect. If the amount of the porous carbon material used is high, the dispersibility of the porous carbon material becomes poor and agglomeration occurs, which is not conducive to obtaining a homogeneous electrode composition. If the amount of the porous carbon material used is low, it will affect the desalination effect.

[0015] In the present invention, the mass ratios of the binder to the porous carbon material and the binder to the oxidation-modified conductive carbon material need to meet the above ranges. 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. If the amount of the binder used is low, the oxidation-modified conductive carbon material and the porous carbon material are likely to fall off during the preparation of the electrode, affecting the service life and desalination rate of the electrode. If the amount of the oxidation-modified conductive carbon material used is low, the improvement in conductivity is small. If the amount of the oxidation-modified conductive carbon material used is high, it will affect the desalination effect. If the amount of the porous carbon material used is high, the dispersibility of the porous carbon material becomes poor and agglomeration occurs, which is not conducive to obtaining a homogeneous electrode composition. If the amount of the porous carbon material used is low, it will affect the desalination effect.

[0016] According to some embodiments of the present invention, at least some of the porous carbon material and the oxidation-modified conductive carbon material in the electrode composition are connected by hydrogen bonds and / or physical entanglement. In the electrode composition of the present invention, the oxidation-modified conductive carbon material contains oxygen-containing functional groups, and the surface of the porous carbon material also contains some oxygen-containing functional groups. Hydrogen bonds are formed between the oxygen-containing functional groups of some of the porous carbon material and the oxidation-modified conductive carbon material, and they are connected together through hydrogen bond action. And / or, there is a physical entanglement effect between some of the porous carbon material and the oxidation-modified conductive carbon material, and they are dispersed through hydrogen bonds and / or physical entanglement, improving the dispersibility of the porous carbon material and avoiding the agglomeration phenomenon of the porous carbon material caused by electrostatic interaction. During the preparation of the electrode, the amount of the binder used can also be reduced, reducing the influence of the non-conductive binder on the conductivity of the electrode composition.

[0017] According to some embodiments of the present invention, the porous carbon material is selected from activated carbon, oxidized modified activated carbon, or a combination thereof; according to some embodiments of the present invention, the porous carbon material is oxidized modified activated carbon. When the porous carbon material is oxidized modified activated carbon, the amount of oxygen-containing functional groups in the porous carbon material is relatively high, and more hydrogen bonds can be formed between the oxidized modified activated carbon and the oxidized modified conductive carbon material. Compared with activated carbon, the dispersion effect of using oxidized modified activated carbon is better, and the effect of reducing the usage amount of the binder is better. In addition, oxidized modified activated carbon has a better hydrophilic effect than activated carbon and is more suitable for the water treatment field.

[0018] According to some embodiments of the present invention, 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%, 10%; according to some embodiments of the present invention, the porous carbon material is oxidized modified activated carbon, and the mass percentage of oxygen in the oxidized modified activated carbon is 2-8%; according to some embodiments of the present invention, the porous carbon material is oxidized modified activated carbon, and the mass percentage of oxygen in the oxidized modified activated carbon is 4-7%. When 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. If the oxygen content in the oxidized modified activated carbon is relatively low (for example, less than 1%), the dispersibility of the oxidized modified activated carbon will decrease and the usage amount of the binder will be relatively high.

[0019] According to some embodiments of the present invention, 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%, 30%; according to some embodiments of the present invention, the mass percentage of oxygen in the oxidized modified conductive carbon material is 1-15%; according to some embodiments of the present invention, the mass percentage of oxygen in the oxidized modified conductive carbon material is 1-10%; according to some embodiments of the present invention, the mass percentage of oxygen in the oxidized modified conductive carbon material is 2-8%. When 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. If the oxygen content in the oxidized modified conductive carbon material is relatively low (for example, less than 1%), the dispersibility of the oxidized modified activated carbon will decrease and the usage amount of the binder will be relatively high.

[0020] According to some embodiments of the present invention, the conductive carbon material is selected from at least one of graphene, carbon nanotubes, conductive carbon black, and carbon fibers. Introducing the above conductive carbon material into the electrode composition of the present invention can further improve the conductivity. Moreover, by oxidative modification, the surface of the conductive carbon material is provided with 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 usage amount of the binder.

[0021] According to some embodiments of the present invention, the porous carbon material is granular; the conductive carbon material is selected from carbon nanotubes, carbon fibers, or a combination thereof. When the porous carbon material is granular and the conductive carbon material is non-granular (i.e., carbon nanotubes, carbon fibers, or a combination thereof), it is beneficial for the physical entanglement between the non-granular conductive carbon material and the granular porous carbon material, which is beneficial for constructing a connected conductive network, improving the dispersibility of the porous carbon material while reducing the usage amount of the binder.

[0022] According to some embodiments of the present invention, the electrode composition further includes a solvent. The role of the solvent is to disperse the binder, the porous carbon material, and the oxidatively modified conductive carbon material, which is beneficial for processing the electrode composition into an electrode and improving the processing performance of the electrode composition.

[0023] According to some embodiments of the present invention, based on the mass percentage of the electrode composition being 100%, the mass percentage of the solvent 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 invention, based on the mass percentage of the electrode composition being 100%, the mass percentage of the solvent is 60 - 80%. If the dosage of the solvent is too large, the solid content of the electrode composition is too low, which is not conducive to the processing and production of the electrode. If the dosage of the solvent is too small, the solid content of the electrode composition is too high, which is not conducive to obtaining an electrode film with good thickness uniformity.

[0024] According to some embodiments of the present invention, 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 solvent used in the present invention has less environmental pollution, higher safety, low cost, and is easy to volatilize, which is beneficial for obtaining an electrode film with higher thickness uniformity.

[0025] According to some embodiments of the present invention, the binder is selected from at least one of polyacrylic acid, polyethylene glycol, polyvinyl alcohol, polyamic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, carboxymethyl cellulose, sodium carboxymethyl cellulose, and styrene-butadiene rubber. Compared with other binders in the prior art, the binder in the present invention has less influence on the electrical conductivity of the electrode composition during use and has better compatibility with the porous carbon material and the oxidized modified conductive carbon material.

[0026] According to some embodiments of the present invention, the weight-average molecular weight of the binder is 5000 to 2000000. For example, it 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, higher than 2000000, the viscosity of the binder is too large, which is not conducive to the dispersion of the porous carbon material and the oxidized modified conductive carbon material.

[0027] The second aspect of the present invention provides a preparation method of the electrode composition provided by the first aspect of the present invention, including the following steps: mixing the oxidized modified conductive carbon material, the porous carbon material, the binder, and an optionally added solvent to obtain the composition.

[0028] The technical solution of the present invention regarding the preparation method of the electrode composition has at least the following beneficial effects: The present invention uses the oxidized modified conductive carbon material, the porous carbon material, and the binder as raw materials, which have a wide range of sources and low costs. At the same time, the preparation method of the present invention is obtained by physically mixing the raw materials evenly. The preparation method is simple, the reaction conditions are mild, there is no requirement for equipment, and it can be mass-produced industrially.

[0029] According to some embodiments of the present invention, the preparation method includes the following steps:

[0030] S1: Mix the binder with a part of the solvent to obtain a binder dispersion; mix the oxidized modified conductive carbon material and the porous carbon material with the remaining solvent to obtain a conductive dispersion;

[0031] S2: After mixing the binder dispersion liquid and the conductive dispersion liquid, the electrode composition is obtained.

[0032] In the present invention, the binder dispersion liquid and the conductive dispersion liquid are first prepared separately and then mixed. By adopting this preparation method, it is beneficial to the mixing and dispersion among the binder, the oxidation-modified conductive carbon material, and the porous carbon material, thereby avoiding the agglomeration of the porous carbon materials due to electrostatic interaction.

[0033] According to some embodiments of the present invention, the mixing step in the preparation method is carried out at 15 - 40 °C. For example, it can be carried out at 15 °C, 16 °C, 17 °C, 18 °C, 19 °C, 20 °C, 21 °C, 22 °C, 24 °C, 26 °C, 28 °C, 30 °C, 32 °C, 34 °C, 36 °C, 37 °C, 38 °C, 39 °C, 40 °C; according to some embodiments of the present invention, the mixing step in the preparation method is carried out at 20 - 35 °C. By adopting a lower mixing temperature in the present invention, energy consumption can be saved and costs can be reduced.

[0034] According to some embodiments of the present invention, in the preparation method, the mixing time is 1 - 10 h. For example, the mixing time can be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h. By adopting a mixing time of 1 - 10 h in the present invention, it can ensure that each raw material is mixed evenly and the dispersion effect of the porous carbon material and the oxidation-modified conductive carbon material is better.

[0035] According to some embodiments of the present invention, the mixing step is carried out by means of stirring and mixing. By adopting the stirring method for mixing in the present invention, the requirements for equipment are relatively low, and the production cost can be reduced.

[0036] According to some embodiments of the present invention, the stirring rate is 100 - 10000 rpm. For example, it can be 100 rpm, 200 rpm, 400 rpm, 500 rpm, 600 rpm, 800 rpm, 1000 rpm, 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 10000 rpm; according to some embodiments of the present invention, the stirring rate is 500 - 5000 rpm; according to some embodiments of the present invention, the stirring rate is 500 - 2000 rpm. Stirring and mixing at a stirring rate of 100 - 10000 rpm can make the porous carbon material and the oxidation-modified conductive carbon material fully dispersed.

[0037] According to some embodiments of the present invention, step S2 is specifically: after mixing the binder dispersion liquid and the conductive dispersion liquid, sieving is performed to obtain the electrode composition. The sieving step can prevent the electrode composition from containing large particles, which may affect subsequent use, and is conducive to obtaining an electrode film with better thickness and composition uniformity.

[0038] According to some embodiments of the present invention, the sieving step is performed using a sieve mesh with 50 - 500 meshes. When the mesh number of the sieve is too small, the particles in the electrode composition are relatively small, which is not conducive to constructing a conductive network and achieving the object of the present invention, and affects the conductive performance of the electrode composition. When the mesh number of the sieve is too large, the electrode composition contains large particle raw materials, which is not conducive to obtaining an electrode film with better thickness and composition uniformity.

[0039] The third aspect of the present invention provides a capacitive deionization electrode, including an electrode layer; the preparation raw material of the electrode layer is the electrode composition provided by the first aspect of the present invention.

[0040] The technical solution of the present invention regarding the capacitive deionization electrode has at least the following beneficial effects: the capacitive deionization electrode in the present invention has a high desalination rate, a large specific surface area, a high pore volume, a low resistivity, a good service life and use stability; it can achieve rapid and efficient removal of anions and cations in water, and has a good application prospect in the field of capacitive deionization water treatment.

[0041] According to some embodiments of the present invention, the maximum adsorption rate of 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 invention, 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 invention, 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 invention has a relatively large adsorption rate, which is beneficial to the rapid adsorption and removal of positive and negative ions in water.

[0042] According to some embodiments of the present invention, the specific surface area of the capacitive deionization electrode is 700 - 2500 m 2 / g. For example, it 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 capacitive deionization electrode in the present invention has a relatively large specific surface area, which is beneficial to obtaining a high desalination rate.

[0043] According to some embodiments of the present invention, the pore volume of the capacitive deionization electrode is 0.8 - 1.1 cm 3 / g. For example, it 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 invention has an appropriate pore volume, which is beneficial to the adsorption and intercalation / deintercalation of positive and negative ions in water.

[0044] According to some embodiments of the present invention, the resistivity of the capacitive deionization electrode is 0.3 to 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 invention has a low resistivity and excellent electrical conductivity.

[0045] According to some embodiments of the present invention, the desalination rate of the capacitive deionization electrode at a working voltage of 1.5 to 2 V is not less than 60%. 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 invention has a high desalination rate in a wide voltage range.

[0046] According to some embodiments of the present invention, the pore diameter of the pores in the capacitive deionization electrode is in the micron range.

[0047] The fourth aspect of the present invention provides a water treatment device, including the capacitive deionization electrode provided in the third aspect of the present invention.

[0048] According to some embodiments of the present invention, the water treatment device includes a purified water device, a water desalination device, and a water softening device.

[0049] The fifth aspect of the present invention provides the application of the electrode composition provided in the first aspect of the present invention and / or the capacitive deionization electrode provided in the third aspect of the present invention in the field of water treatment.

[0050] Other features and advantages of the present invention will be described in the subsequent specification, and some will be obvious from the specification or understood by implementing the present invention. Brief Description of the Drawings

[0051] Figure 1 It is a surface topography diagram of the capacitive deionization electrode in Example 8.

[0052] Figure 2It is a test graph of the desalination performance and voltage relationship curve of the capacitive deionization electrode in Example 8.

[0053] Figure 3 It is a test graph of the desalination performance and voltage relationship curve of the capacitive deionization electrode in Example 9. Detailed implementation manners

[0054] The following further elaborates on the specific implementation of the present invention in conjunction with the accompanying drawings and examples. However, the implementation and protection of the present invention are not limited thereto. It should be noted that for the processes not specifically described in detail below, those skilled in the art can implement or understand them with reference to the prior art. Reagents or instruments without indicating the manufacturer can be obtained as conventional products through commercial purchase.

[0055] When the inventor was researching and developing the composition for capacitive deionization electrodes, in order to solve the problems that activated carbon has poor hydrophilicity and the pore size is mainly micropores, which affects the mass transfer and diffusion of hydrated ions, and the deionization efficiency and effect are poor, methods such as strong alkali heat treatment, template method, chemical vapor deposition method, etc. were respectively tried to prepare porous carbon material electrodes. Although the specific surface area, pore size or hydrophilicity of the porous carbon material electrodes has been improved to a certain extent, it still cannot meet the requirements of quickly and efficiently adsorbing anions and cations in water, and the porous carbon materials prepared by these methods all have certain defects. These defects can improve the hydrophilicity of the porous carbon materials, but also reduce the conductivity of the porous carbon materials to a certain extent. Based on this, the inventor continued to research and develop the porous carbon material electrodes, and tried to perform high-temperature treatment on the porous carbon materials to reduce the defects on the surface of the porous carbon materials. The conductivity of the porous carbon materials has been improved to a certain extent, but it still cannot meet the use requirements. In addition, the methods of strong alkali heat treatment, template method, chemical vapor deposition method, and high-temperature treatment all have the problems of cumbersome process operation, high cost, poor repeatability, and are not suitable for large-scale industrial production.

[0056] The inventor continued to research and develop the porous carbon material electrodes and tried to introduce conductive carbon materials into the porous carbon materials. The inventor found that a large amount of non-conductive binder needs to be added during the preparation of the electrodes, the resistivity of the electrodes is high, the conductivity is poor, and the conductive carbon materials and the porous carbon materials belong to different materials. There will be a large amount of aggregation of the porous carbon materials during the preparation of the electrodes, and the dispersibility is poor, which cannot meet the use requirements of the capacitive deionization electrodes.

[0057] The inventor continued the research and development of the composition for capacitive deionization electrodes, introducing an oxidized conductive carbon material and a porous carbon material. Partial hydrogen bonds are formed between the oxidized conductive carbon material and the porous carbon material, and the oxidized conductive carbon material and the porous carbon material are connected through the action of hydrogen bonds, avoiding the agglomeration of the porous carbon material. Secondly, there is also a physical entanglement between carbon nanotubes oxidized and / or oxidized modified carbon fibers, etc. and the granular porous carbon material, so that the oxidized conductive carbon material and the porous carbon material are physically entangled with each other. When preparing the electrode, the usage amount of the binder can be reduced, and the influence of the binder usage on the conductivity of the electrode can be reduced. Moreover, the introduction of the oxidized conductive carbon material can also reduce the resistivity of the electrode and improve its conductivity.

[0058] In order to further improve the desalination efficiency and adsorption rate, the inventor tried that the electrodes made of the oxidized conductive carbon material and the oxidized activated carbon have a relatively high specific surface area, a relatively large pore volume, and a relatively large pore diameter, which can enable the rapid mass transfer and diffusion of hydrated ions, improve the rate of adsorbing anions and cations in water, and make the maximum adsorption rate of the electrode reach 200 - 400 mg / (m 2 ·min). In addition, both the oxidized conductive carbon material and the oxidized activated carbon have good hydrophilic properties, which can meet the material property requirements of capacitive deionization electrodes in the water treatment field.

[0059] In some embodiments of the present invention, the present invention provides a composition for electrodes, which includes a porous carbon material, an oxidized conductive carbon material, and a binder. The mass ratio of the binder, the porous carbon material, and the oxidized conductive carbon material is 1:(4 - 96):(0.2 - 15).

[0060] In some embodiments of the present invention, the porous carbon material and the oxidized conductive carbon material are connected by hydrogen bonds. The oxidized conductive carbon material contains oxygen-containing functional groups, and the surface of the porous carbon material also contains some oxygen-containing functional groups. The porous carbon material and the oxidized conductive carbon material can be connected through hydrogen bonds. There is also physical entanglement between the porous carbon material and the oxidized conductive carbon material. Through the action of hydrogen bonds and physical entanglement, the dispersibility of the porous carbon material is improved, and the granular porous carbon material is prevented from agglomerating due to electrostatic interaction.

[0061] In some embodiments of the present invention, 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, it can be 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 invention, 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 invention, 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 invention, 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).

[0062] In the present invention, 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, it will affect the conductivity of the electrode composition. If the amount of the binder used is low, the oxidatively modified conductive carbon material and the porous carbon material are likely 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 low, the improvement in conductivity is small. If the amount of the oxidatively modified conductive carbon material used is high, it will affect the desalination effect. If the amount of the porous carbon material used is high, the dispersibility of the porous carbon material becomes poor and agglomeration occurs, which is not conducive to obtaining a homogeneous electrode composition. If the amount of the porous carbon material used is low, it will affect the desalination effect.

[0063] In some embodiments of the present invention, at least some 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 invention, 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. Hydrogen bonds are formed between the oxygen-containing functional groups of some of the porous carbon material and the oxidatively modified conductive carbon material, and they are connected together by the action of hydrogen bonds. The remaining porous carbon materials are dispersed by physical mixing such as winding, improving the dispersibility of the porous carbon material and avoiding the agglomeration phenomenon caused by electrostatic interaction of the porous carbon material. During the preparation of the electrode, the amount of the binder used can also be reduced, reducing the influence of the non-conductive binder on the conductivity of the electrode composition.

[0064] In some embodiments of the present invention, the porous carbon material is selected from activated carbon, oxidatively modified activated carbon, or a combination thereof. In some embodiments of the present invention, 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 relatively high (specific surface area greater than 1000 m 2 / g), and it has a large number of pores (pore volume greater than 0.57 cm 3 / g). During desalination, positive and negative ions can be adsorbed in the porous carbon material. The large specific surface area and large pore volume are both beneficial to the improvement of 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 relatively high, which can form more hydrogen bonds with the oxidatively modified conductive carbon material. Compared with activated carbon, the dispersing effect of using oxidatively modified activated carbon is better, and the effect of reducing the amount of the binder used is better. In addition, oxidatively modified activated carbon has a better hydrophilic effect than activated carbon and is more suitable for use in the field of water treatment.

[0065] In some embodiments of the present invention, the oxidized activated carbon is prepared by mixing and reacting activated carbon with an oxidizing agent. In some embodiments of the present invention, 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 activated carbon in a solution of the oxidizing agent for an oxidation reaction, oxygen-containing functional groups such as carboxyl groups and hydroxyl groups are introduced into the activated carbon. The oxidation effect is good, and the damage to the activated carbon is small. It can enhance the binding force between the activated carbon and the oxidized conductive carbon material. In addition, the introduction of oxygen-containing functional groups can also improve the hydrophilicity of the activated carbon.

[0066] In some embodiments of the present invention, the porous carbon material is oxidized activated carbon. The mass percentage of oxygen in the oxidized activated carbon is 1-10%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. In some embodiments of the present invention, the porous carbon material is oxidized activated carbon. The mass percentage of oxygen in the oxidized activated carbon is 2-8%. In some embodiments of the present invention, the porous carbon material is oxidized activated carbon. The mass percentage of oxygen in the oxidized activated carbon is 4-7%. When the oxygen content in the oxidized activated carbon is too high (for example, greater than 10%), it will affect the electrical conductivity of the electrode. If the oxygen content in the oxidized activated carbon is relatively low (for example, less than 1%), the dispersibility of the oxidized activated carbon decreases and the amount of binder used is relatively high.

[0067] In some embodiments of the present invention, the water contact angle of the oxidized activated carbon is 35-87°. The oxidized activated carbon in the present invention has excellent hydrophilicity and can be used to remove positive and negative ions in water.

[0068] In some embodiments of the present invention, the mass percentage of oxygen in the oxidized 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%, 30%. In some embodiments of the present invention, the mass percentage of oxygen in the oxidized conductive carbon material is 1-15%. In some embodiments of the present invention, the mass percentage of oxygen in the oxidized conductive carbon material is 1-10%. In some embodiments of the present invention, the mass percentage of oxygen in the oxidized conductive carbon material is 2-8%. When the oxygen content in the oxidized conductive carbon material is too high (for example, greater than 30%), it will affect the electrical conductivity of the electrode. If the oxygen content in the oxidized conductive carbon material is relatively low (for example, less than 1%), the dispersibility of the oxidized activated carbon decreases and the amount of binder used is relatively high.

[0069] In the present invention, the mass percentage of oxygen in the oxidized conductive carbon material may be the same as or different from that in the oxidized activated carbon. When the mass percentage of oxygen in the oxidized activated carbon is 1-10%, and the mass percentage of oxygen in the oxidized conductive carbon material is 1-30%, more hydrogen bonds can be formed between the oxidized conductive carbon material and the oxidized activated carbon, which is beneficial to their dispersion and can reduce the usage amount of the binder. When the mass percentage of oxygen in the oxidized activated carbon is relatively high, the hydrophilic property is better.

[0070] In some embodiments of the present invention, the conductive carbon material is selected from at least one of graphene, carbon nanotubes, conductive carbon black, and carbon fiber. Introducing the above-mentioned conductive carbon material into the electrode composition of the present invention can further improve the conductivity. Moreover, by oxidation modification, the surface of the conductive carbon material is provided with 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 usage amount of the binder.

[0071] In some embodiments of the present invention, the oxidized conductive carbon material is prepared by mixing and reacting the conductive carbon material with an oxidant. In some embodiments of the present invention, the oxidant 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 the solution of the oxidant to undergo an oxidation reaction, oxygen-containing functional groups such as carboxyl groups and hydroxyl groups are introduced into the conductive carbon material, with good oxidation effect and little damage to the conductive carbon material, which can enhance the binding force between the conductive carbon material and the porous carbon material.

[0072] In some embodiments of the present invention, the conductivity of the oxidized conductive carbon material is 0.21-0.59 Ω·cm. The oxidized conductive carbon material in the present invention has a relatively high conductivity. Introducing it into the electrode composition of the present invention can significantly improve the conductivity.

[0073] In some embodiments of the present invention, the aspect ratio of the carbon fiber is 2-30; in some embodiments of the present invention, the aspect ratio of the carbon nanotube is 2000-10000. Selecting the carbon fiber and carbon nanotube with the above aspect ratios is beneficial to the physical entanglement between the oxidized conductive carbon material and the porous carbon material, and is beneficial to constructing a connected conductive network, while improving the dispersibility of the porous carbon material and reducing the usage amount of the binder.

[0074] In some embodiments of the present invention, the porous carbon material is granular; the conductive carbon material is selected from carbon nanotubes, carbon fibers, or a combination thereof. When the porous carbon material is granular and the conductive carbon material is non-granular (i.e., carbon nanotubes, carbon fibers, or a combination thereof), it is beneficial for the physical entanglement between the non-granular conductive carbon material and the granular porous carbon material, and is beneficial for constructing a connected conductive network, while improving the dispersibility of the porous carbon material and reducing the usage amount of the binder.

[0075] In some embodiments of the present invention, the particle size of the porous carbon material is 25 - 270 μm. The particle size of the porous carbon material in the present invention is uniform, and when applied to the electrode composition of the present invention, it is beneficial for the dispersion of the porous carbon material.

[0076] In some embodiments of the present invention, the electrode composition further includes a solvent. The role of the solvent is to disperse the binder, the porous carbon material, and the oxidation-modified conductive carbon material, which is beneficial for processing the electrode composition into an electrode and improving the processing performance of the electrode composition.

[0077] In some embodiments of the present invention, based on the mass percentage of the electrode composition being 100%, the mass percentage of the solvent 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%; in some embodiments of the present invention, based on the mass percentage of the electrode composition being 100%, the mass percentage of the solvent is 60 - 80%. If the dosage of the solvent is too large, the solid content of the electrode composition is too low, which is not conducive to the processing and production of the electrode; if the dosage of the solvent is too small, the solid content of the electrode composition is too high, which is not conducive to obtaining an electrode film with good thickness uniformity.

[0078] In some embodiments of the present invention, 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 invention, the solvent is selected from at least one of N-methylpyrrolidone and water. The solvent used in the present invention has less environmental pollution, higher safety, low cost, and is easy to volatilize, which is beneficial for obtaining an electrode film with higher thickness uniformity.

[0079] In some embodiments of the present invention, the binder is selected from at least one of polyacrylic acid, polyethylene glycol, polyvinyl alcohol, polyamic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, carboxymethyl cellulose, sodium carboxymethyl cellulose, and styrene-butadiene rubber. Compared with other binders in the prior art, the binder in the present invention has less influence on the electrical conductivity of the electrode composition during use, and has better compatibility with the porous carbon material and the oxidized and modified conductive carbon material.

[0080] In some embodiments of the present invention, the weight-average molecular weight of the binder is 5000 - 2000000. For example, it 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 invention, the weight-average molecular weight of the binder is 8000 - 1000000. In some embodiments of the present invention, 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 it cannot function as a binder. When the weight-average molecular weight of the binder is too large, for example, higher than 2000000, the viscosity of the binder is too large, which is not conducive to the dispersion of the porous carbon material and the oxidized and modified conductive carbon material, and is even less conducive to obtaining an electrode film with high thickness uniformity.

[0081] In some embodiments of the present invention, the present invention also provides a preparation method of the above electrode composition, including the following steps: mixing the oxidized and modified conductive carbon material, the porous carbon material, the binder, and optionally added solvent to obtain.

[0082] The present invention uses the oxidized and modified conductive carbon material, the porous carbon material, and the binder as raw materials. The raw materials have a wide source and low cost. At the same time, the preparation method of the present invention is obtained by physically mixing the raw materials evenly. The preparation method is simple, the reaction conditions are mild, there is no requirement for equipment, and it can be mass-produced industrially.

[0083] In some embodiments of the present invention, the preparation method includes the following steps:

[0084] S1: Mix the binder with a part of the solvent to obtain a binder dispersion; mix the oxidized and modified conductive carbon material, the porous carbon material with the remaining solvent to obtain a conductive dispersion;

[0085] S2: After mixing the binder dispersion and the conductive dispersion, a composition for an electrode is prepared.

[0086] In the present invention, the binder dispersion and the conductive dispersion are first prepared separately, and then the two are mixed. By adopting this preparation method, it is beneficial to the mixing and dispersion among the binder, the oxidatively modified conductive carbon material, and the porous carbon material, thereby avoiding the agglomeration of the porous carbon materials due to electrostatic interaction.

[0087] In some embodiments of the present invention, the mixing step in the preparation method is carried out at 15 - 40 °C. For example, the mixing can be carried out at 15 °C, 16 °C, 17 °C, 18 °C, 19 °C, 20 °C, 21 °C, 22 °C, 24 °C, 26 °C, 28 °C, 30 °C, 32 °C, 34 °C, 36 °C, 37 °C, 38 °C, 39 °C, 40 °C; in some embodiments of the present invention, the mixing step in the preparation method is carried out at 20 - 35 °C. By adopting a lower mixing temperature in the present invention, energy consumption can be saved.

[0088] In some embodiments of the present invention, in the preparation method, the mixing time is 1 - 10 h. For example, the mixing time can be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h. By adopting a mixing time of 1 - 10 h in the present invention, it can ensure that each raw material is mixed evenly, and the dispersion effect of the porous carbon material and the oxidatively modified conductive carbon material is better.

[0089] In some embodiments of the present invention, the mixing step is carried out by means of stirring and mixing. By adopting the way of stirring for mixing in the present invention, the requirements for equipment are relatively low, and the production cost can be reduced.

[0090] In some embodiments of the present invention, the stirring rate is 100 - 10000 rpm. For example, it can be 100 rpm, 200 rpm, 400 rpm, 500 rpm, 600 rpm, 800 rpm, 1000 rpm, 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 10000 rpm; in some embodiments of the present invention, the stirring rate is 500 - 5000 rpm; in some embodiments of the present invention, the stirring rate is 500 - 2000 rpm. Stirring and mixing at a stirring rate of 100 - 10000 rpm can make the porous carbon material and the oxidatively modified conductive carbon material fully dispersed.

[0091] In some embodiments of the present invention, step S2 is specifically as follows: After mixing the binder dispersion liquid and the conductive dispersion liquid, sieving is performed to obtain the electrode composition. The sieving step can prevent the electrode composition from containing large particles, which may affect subsequent use, and is beneficial to obtaining an electrode film with better thickness and composition uniformity.

[0092] In some embodiments of the present invention, the sieving step is performed by filtering with a sieve having a mesh size of 50 to 500 meshes. When the mesh size of the sieve is too small, the particles in the electrode composition are small, which is not conducive to constructing a conductive network and affects the conductivity of the electrode composition. When the mesh size of the sieve is too large, the electrode composition contains large particle raw materials, which is not conducive to obtaining an electrode film with better thickness and composition uniformity.

[0093] In some embodiments of the present invention, the present invention also provides a capacitive deionization electrode, including an electrode layer; the preparation raw material of the electrode layer is the above-mentioned electrode composition.

[0094] The capacitive deionization electrode in the present invention has a high desalination rate, a large specific surface area, a high pore volume, a low resistivity, a good service life and use stability; it can achieve rapid and efficient removal of anions and cations in water, and has good application prospects in the field of capacitive deionization water treatment.

[0095] In some embodiments of the present invention, the maximum adsorption rate of 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); In some embodiments of the present invention, the maximum adsorption rate of anions and cations of the capacitive deionization electrode is 240 - 350 mg / (m 2 ·min); In some embodiments of the present invention, 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 invention has a relatively large adsorption rate, which is beneficial to the rapid adsorption and removal of various positive and negative ions in water.

[0096] In some embodiments of the present invention, the specific surface area of the capacitive deionization electrode is 700 - 2500 m 2 / g. For example, it 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 invention, the specific surface area of the capacitive deionization electrode is 900 - 2200 m 2 / g; In some embodiments of the present invention, the specific surface area of the capacitive deionization electrode is 900 - 1800 m 2 / g; In some embodiments of the present invention, the specific surface area of the capacitive deionization electrode is 900 - 1200 m 2 / g. The capacitive deionization electrode in the present invention has a relatively large specific surface area, which is beneficial to obtaining a high desalination rate.

[0097] In some embodiments of the present invention, the pore volume of the capacitive deionization electrode is 0.8 to 1.1 cm 3 / g. For example, it 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 invention has an appropriate pore volume, which is beneficial to the adsorption and intercalation / deintercalation of positive and negative ions in water.

[0098] In some embodiments of the present invention, the resistivity of the capacitive deionization electrode is 0.3 to 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 invention has a low resistivity and excellent electrical conductivity.

[0099] In some embodiments of the present invention, the desalination rate of the capacitive deionization electrode at a working voltage of 1.5 to 2 V is not less than 60%. 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 invention has a high desalination rate in a wide voltage range.

[0100] In some embodiments of the present invention, a microporous structure exists in the capacitive deionization electrode. A large number of microporous structures exist in the capacitive deionization electrode of the present invention, which can enable positive and negative ions in water to be adsorbed in the micropores of the capacitive deionization electrode.

[0101] In some embodiments of the present invention, the present invention also provides a water treatment device, including the above capacitive deionization electrode.

[0102] In some embodiments of the present invention, the water treatment device includes a purified water device, a water desalination device, and a water softening device.

[0103] In some embodiments of the present invention, the water treatment device includes two oppositely arranged above capacitive deionization electrodes.

[0104] In the water treatment equipment of the present invention, the above-mentioned capacitive deionization electrode is installed. During operation, a DC external voltage is applied to the capacitive deionization electrode, thereby forming an electrostatic field between the two capacitive deionization electrodes, causing positive and negative ions in the water to move directionally to the surface of the capacitive deionization electrode with the opposite charge to theirs and being stored on the surface of the capacitive deionization electrode, reducing the salt concentration in the solution, and thus achieving the purpose of deionization. Reversing the power supply or not applying voltage causes the capacitive deionization electrode to discharge, and the ions adsorbed on the surface of the capacitive deionization electrode are released back into the solution again, and the capacitive deionization electrode is regenerated. The water treatment equipment in the present invention has advantages such as low energy consumption, no secondary pollution, and environmental friendliness, and has a high desalination rate and desalination rate.

[0105] In some embodiments of the present invention, the above-mentioned electrode composition can be used in the field of water treatment.

[0106] In some embodiments of the present invention, the above-mentioned capacitive deionization electrode can be applied in the field of water treatment.

[0107] The following further elaborates on the implementation of the present invention with specific examples by way of illustrative examples:

[0108] The specific preparation method of the carbon nanotubes oxidized used in the embodiments of the present invention is as follows: The carbon nanotubes and nitric acid solution (the concentration of nitric acid is 12 mol / L) are placed in a three-necked flask and reacted at a temperature of 80 °C. Then, the oxidized carbon nanotubes are washed with pure water until the pH value is neutral, and are obtained after drying. By changing the dosage ratio of carbon nanotubes and nitric acid and the reaction time, carbon nanotubes oxidized with different oxygen contents can be prepared.

[0109] The activated carbon modified by oxidation used in the embodiments of the present invention has better hydrophilicity after oxidation modification, and it can be prepared by oxidizing activated carbon with an oxidant with reference to the preparation method of carbon nanotubes oxidized.

[0110] Example 1

[0111] This example provides an electrode composition, and the electrode composition is prepared by the following preparation method. The preparation steps include:

[0112] Polyvinylidene fluoride and N-methylpyrrolidone are mixed at a mass ratio of 1:20 and stirred and dispersed for 3 hours at 25 °C by a homogenizer at a stirring speed of 1000 rpm to obtain a dispersion of the binder material, wherein the weight-average molecular weight of polyvinylidene fluoride is 110000.

[0113] Mix carbon nanotube oxide (i.e., oxidized and modified conductive carbon material), oxidized and modified activated carbon (i.e., porous carbon material) with N-methylpyrrolidone in a mass ratio of 1:10:20, and stir for 3 hours at 25°C using a homogenizer with a stirring speed of 1000 rpm; then mix with the dispersion of the above binder material and continue stirring for 5 hours at a stirring speed of 1000 rpm; filter the mixed slurry through a stainless steel mesh with a mesh size of 200 mesh to obtain the electrode composition in this example.

[0114] In the electrode composition in this example, the mass percentage of solids (solids refer to polyvinylidene fluoride, carbon nanotube oxide, and oxidized and modified activated carbon) is 25%. Among them, based on the total mass percentage of solids in the electrode composition being 100%, the mass percentage of polyvinylidene fluoride is 6.3%, the mass percentage of carbon nanotube oxide is 8.5%, and the mass percentage of oxidized and modified activated carbon is 85.2%. The mass percentage of oxygen in the carbon nanotube oxide is 10%, and the mass percentage of oxygen in the oxidized and modified activated carbon is 2%.

[0115] Example 2

[0116] This example provides an electrode composition, which is prepared by the following preparation method. The preparation steps include:

[0117] Mix sodium carboxymethyl cellulose with water in a mass ratio of 1:20, and stir and disperse for 3 hours at 25°C using a homogenizer with a stirring speed of 1000 rpm to obtain a dispersion of the binder material, where the weight-average molecular weight of sodium carboxymethyl cellulose is 80000.

[0118] Mix carbon nanotube oxide, oxidized and modified activated carbon with water in a mass ratio of 1:10:20, and stir for 5 hours at 25°C using a homogenizer with a stirring speed of 1000 rpm. Then mix with the dispersion of the above binder material and continue stirring for 10 hours at a stirring speed of 1000 rpm. Filter the mixed slurry through a stainless steel mesh with a mesh size of 200 mesh to obtain the electrode composition in this example.

[0119] In the electrode composition in this example, the mass percentage of solids (solids refer to sodium carboxymethyl cellulose, carbon nanotube oxide, and oxidized and modified activated carbon) is 25%. Among them, based on the total mass percentage of solids in the electrode composition being 100%, the mass percentage of sodium carboxymethyl cellulose is 6.3%, the mass percentage of carbon nanotube oxide is 8.5%, and the mass percentage of oxidized and modified activated carbon is 85.2%. Among them, the mass percentage of oxygen in the carbon nanotube oxide is 10%, and the mass percentage of oxygen in the oxidized and modified activated carbon is 2%.

[0120] Example 3

[0121] This example provides a composition for an electrode, and the composition for the electrode is prepared by the following preparation method. The preparation steps include:

[0122] Mix polyvinylidene fluoride and N-methylpyrrolidone in a mass ratio of 1:20, and stir and disperse them for 3 hours at 25 °C with a stirring speed of 1000 rpm using a homogenizer to obtain a dispersion of the binder material, wherein the weight-average molecular weight of polyvinylidene fluoride is 110,000.

[0123] Mix graphene oxide, oxidized modified activated carbon and N-methylpyrrolidone in a mass ratio of 1:10:20, and stir for 3 hours at 25 °C with a stirring speed of 1000 rpm using a homogenizer; then mix with the above dispersion of the binder material and continue to stir for 5 hours with a stirring speed of 1000 rpm; filter the mixed slurry through a stainless steel mesh with a mesh number of 200 to obtain the composition for the electrode in this example.

[0124] In the composition for the electrode in this example, the mass percentage of solids (the solids refer to polyvinylidene fluoride, graphene oxide and oxidized modified activated carbon) is 25%. Among them, based on the total mass percentage of solids in the composition for the electrode being 100%, the mass percentage of polyvinylidene fluoride is 6.3%, the mass percentage of graphene oxide is 8.5%, and the mass percentage of oxidized modified activated carbon is 85.2%. Among them, the mass percentage of oxygen in graphene oxide is 1%, and the mass percentage of oxygen in oxidized modified activated carbon is 8%.

[0125] Example 4

[0126] This example provides a composition for an electrode, and the composition for the electrode is prepared by the following preparation method. The preparation steps include:

[0127] Mix sodium carboxymethyl cellulose and water in a mass ratio of 1:20, and stir and disperse them for 3 hours at 25 °C with a stirring speed of 1000 rpm using a homogenizer to obtain a dispersion of the binder material, wherein the weight-average molecular weight of sodium carboxymethyl cellulose is 80,000.

[0128] Mix oxidized conductive carbon black (which is obtained by oxidizing conductive carbon black using the modified Hummers method, and in the modified Hummers method, the oxidants are concentrated sulfuric acid with a mass fraction of 98% and potassium permanganate), oxidized modified activated carbon and water in a mass ratio of 1:10:20, and stir for 5 hours at 25 °C with a stirring speed of 1000 rpm using a homogenizer, then mix with the above dispersion of the binder material and continue to stir for 10 hours with a stirring speed of 1000 rpm, and filter the mixed slurry through a stainless steel mesh with a mesh number of 200 to obtain the composition for the electrode in this example.

[0129] In the electrode composition of this example, the mass percentage of solids (the solids refer to sodium carboxymethyl cellulose, oxidized conductive carbon black, and oxidized modified activated carbon) is 25%. Among them, based on the total mass percentage of solids in the electrode composition being 100%, the mass percentage of sodium carboxymethyl 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%. Among them, 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%.

[0130] Example 5

[0131] This example provides an electrode composition, and this electrode composition is prepared by the following preparation method. The preparation steps include:

[0132] Mix polyacrylonitrile and acetonitrile in a mass ratio of 1:20, and stir and disperse them for 3 hours at 25°C with a stirring speed of 1000 rpm by a homogenizer to obtain a dispersion of the binder material, where the weight-average molecular weight of polyacrylonitrile is 2,000,000.

[0133] Mix oxidized carbon nanotubes (i.e., oxidized modified conductive carbon material), oxidized modified activated carbon (i.e., porous carbon material) and acetonitrile in a mass ratio of 1:7.5:10, and stir them for 3 hours at 25°C with a stirring speed of 1000 rpm by a homogenizer; then mix with the above dispersion of the binder material and continue to stir for 5 hours with a stirring speed of 1000 rpm; filter the mixed slurry through a stainless steel mesh with a mesh number of 200 to obtain the electrode composition in this example.

[0134] In the electrode composition of this example, the mass percentage of solids (the solids refer to polyacrylonitrile, oxidized carbon nanotubes, and oxidized modified activated carbon) is 31%. Among them, based on the total mass percentage of solids in the electrode composition being 100%, 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%. Among them, 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%.

[0135] Example 6

[0136] This example provides an electrode composition, and this electrode composition is prepared by the following preparation method. The preparation steps include:

[0137] Mix polyacrylonitrile and acetonitrile in a mass ratio of 1:7, and stir and disperse them for 3 hours at 25°C with a stirring speed of 1000 rpm by a homogenizer to obtain a dispersion of the binder material, where the weight-average molecular weight of polyacrylonitrile is 2,000,000.

[0138] Mix carbon nanotube oxide (i.e., oxidized and modified conductive carbon material), oxidized and modified activated carbon (i.e., porous carbon material) and acetonitrile in a mass ratio of 1:7.5:10, and stir with a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm; then mix with the dispersion of the above binder material and continue stirring for 5 hours at a stirring speed of 1000 rpm; filter the mixed slurry through a stainless steel mesh with a mesh number of 200 to obtain the electrode composition in this example.

[0139] In the electrode composition in this example, the mass percentage of solids (solids refer to polyacrylonitrile, carbon nanotube oxide and oxidized and modified activated carbon) is 40%. Among them, based on the total mass percentage of solids in the electrode composition being 100%, the mass percentage of polyacrylonitrile is 5.5%, the mass percentage of carbon nanotube oxide is 11.2%, and the mass percentage of oxidized and modified activated carbon is 83.3%. Among them, the mass percentage of oxygen in the carbon nanotube oxide is 10%, and the mass percentage of oxygen in the oxidized and modified activated carbon is 8%.

[0140] Example 7

[0141] This example provides an electrode composition, which is prepared by the following preparation method. The preparation steps include:

[0142] Mix polyacrylonitrile and acetonitrile in a mass ratio of 1:32, and stir and disperse with a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm to obtain a dispersion of the binder material, where the weight average molecular weight of polyacrylonitrile is 2000000.

[0143] Mix carbon nanotube oxide (i.e., oxidized and modified conductive carbon material), oxidized and modified activated carbon (i.e., porous carbon material) and acetonitrile in a mass ratio of 1:12:20, and stir with a homogenizer at 25°C for 3 hours at a stirring speed of 1000 rpm; then mix with the dispersion of the above binder material and continue stirring for 5 hours at a stirring speed of 1000 rpm; filter the mixed slurry through a stainless steel mesh with a mesh number of 200 to obtain the electrode composition in this example.

[0144] In the electrode composition in this example, the mass percentage of solids (solids refer to polyacrylonitrile, carbon nanotube oxide and oxidized and modified activated carbon) is 21%. Among them, based on the total mass percentage of solids in the electrode composition being 100%, the mass percentage of polyacrylonitrile is 7.1%, the mass percentage of carbon nanotube oxide is 7.1%, and the mass percentage of oxidized and modified activated carbon is 85.8%. Among them, the mass percentage of oxygen in the carbon nanotube oxide is 10%, and the mass percentage of oxygen in the oxidized and modified activated carbon is 8%.

[0145] Example 8

[0146] This example provides a capacitive deionization electrode, which includes a substrate and an electrode layer attached to the substrate. The electrode layer is prepared from the electrode composition in Example 1.

[0147] The capacitive deionization electrode in this example is prepared by the following preparation method. The preparation steps include:

[0148] Coat the electrode composition in Example 1 on a titanium foil and dry it to obtain the capacitive deionization electrode in this example.

[0149] Example 9

[0150] This example provides a capacitive deionization electrode, which includes a substrate and an electrode layer attached to the substrate. The electrode layer is prepared from the electrode composition in Example 2.

[0151] The capacitive deionization electrode in this example is prepared by the following preparation method. The preparation steps include:

[0152] Coat the electrode composition in Example 2 on a titanium foil and dry it to obtain the capacitive deionization electrode in this example.

[0153] Example 10

[0154] This example provides a capacitive deionization electrode, which includes a substrate and an electrode layer attached to the substrate. The electrode layer is prepared from the electrode composition in Example 3.

[0155] The capacitive deionization electrode in this example is prepared by the following preparation method. The preparation steps include:

[0156] Coat the electrode composition in Example 3 on a titanium foil and dry it to obtain the capacitive deionization electrode in this example.

[0157] Example 11

[0158] This example provides a capacitive deionization electrode, which includes a substrate and an electrode layer attached to the substrate. The electrode layer is prepared from the electrode composition in Example 4.

[0159] The capacitive deionization electrode in this example is prepared by the following preparation method. The preparation steps include:

[0160] Coat the electrode composition in Example 4 on a titanium foil and dry it to obtain the capacitive deionization electrode in this example.

[0161] Example 12

[0162] This example provides a capacitive deionization electrode, which includes a substrate and an electrode layer attached to the substrate. The electrode layer is prepared using the electrode composition in Example 5.

[0163] The capacitive deionization electrode in this example is prepared using the following preparation method, and the preparation steps include:

[0164] Coat the electrode composition in Example 5 on a titanium foil and dry it to obtain the capacitive deionization electrode in this example.

[0165] Example 13

[0166] This example provides a capacitive deionization electrode, which includes a substrate and an electrode layer attached to the substrate. The electrode layer is prepared using the electrode composition in Example 6.

[0167] The capacitive deionization electrode in this example is prepared using the following preparation method, and the preparation steps include:

[0168] Coat the electrode composition in Example 6 on a titanium foil and dry it to obtain the capacitive deionization electrode in this example.

[0169] Example 14

[0170] This example provides a capacitive deionization electrode, which includes a substrate and an electrode layer attached to the substrate. The electrode layer is prepared using the electrode composition in Example 7.

[0171] The capacitive deionization electrode in this example is prepared using the following preparation method, and the preparation steps include:

[0172] Coat the electrode composition in Example 7 on a titanium foil and dry it to obtain the capacitive deionization electrode in this example.

[0173] Example 15

[0174] This example provides a water purifier, and the electrode of the water purifier in this example uses the capacitive deionization electrode in Example 8.

[0175] Example 16

[0176] This example provides a water purifier, and the electrode of the water purifier in this example uses the capacitive deionization electrode in Example 9.

[0177] Example 17

[0178] This example provides a water purifier, and the electrode of the water purifier in this example uses the capacitive deionization electrode in Example 10.

[0179] Example 18

[0180] This example provides a water purifier. The electrode of the water purifier in this example uses the capacitive deionization electrode in Example 11.

[0181] Example 19

[0182] This example provides a water purifier. The electrode of the water purifier in this example uses the capacitive deionization electrode in Example 12.

[0183] Example 20

[0184] This example provides a water purifier. The electrode of the water purifier in this example uses the capacitive deionization electrode in Example 13.

[0185] Example 21

[0186] This example provides a water purifier. The electrode of the water purifier in this example uses the capacitive deionization electrode in Example 14.

[0187] Performance test:

[0188] (1) Surface morphology test

[0189] The surface morphology of the capacitive deionization electrode in Example 8 was tested using a scanning electron microscope. The specific test method is as Figure 1 shown. It can be seen from Figure 1 that the capacitive deionization electrode in Example 8 has a loose and porous surface morphology. The pore size distribution is mainly in the micron range, which has no restrictive effect on the mass transfer and diffusion of hydrated ions. The hydrated ions can quickly and efficiently pass through the pores on the surface of the capacitive deionization electrode and then be adsorbed inside the capacitive deionization electrode to achieve desalination. In addition, it can also be seen from Figure 1 that the oxidized activated carbon and carbon nanotubes are intertwined with each other, and the oxidized activated carbon is evenly dispersed without agglomeration. The reason is that oxygen-containing functional groups are distributed on the surfaces of both the oxidized activated carbon and carbon nanotubes. Hydrogen bonds are formed between these oxygen-containing functional groups, which connect the oxidized activated carbon and carbon nanotubes. In addition, the carbon nanotubes and the oxidized activated carbon can also be connected through physical entanglement. Through chemical and physical entanglement, the oxidized activated carbon can be evenly dispersed, avoiding the agglomeration of granular oxidized activated carbon due to electrostatic interaction, which affects the surface composition uniformity and electrical conductivity of the capacitive deionization electrode.

[0190] (2) TDS test

[0191] The capacitive deionization electrode in Example 8 was placed in an 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 conduct a desalination performance test. Among them, the calculation formula for the desalination rate is: desalination rate % = (inlet concentration - outlet concentration) / original inlet concentration × 100%, and the calculation formula for the adsorption rate is: adsorption rate = (desalination rate × inlet concentration × flow rate) / electrode area. The TDS and voltage relationship curve of the desalination performance test of the capacitive deionization electrode in Example 8 is as Figure 2 shown. It can be seen from Figure 2 that the desalination rate of the capacitive deionization electrode in Example 8 reached 86.1% after 2 minutes of use, and the maximum adsorption rate was 323 mg / (m 2 ·min).

[0192] The capacitive deionization electrode in Example 9 was placed in an 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 conduct a desalination performance test. Among them, the calculation formula for the desalination rate is: desalination rate % = (inlet concentration - outlet concentration) / original inlet concentration × 100%, and the calculation formula for the adsorption rate is: adsorption rate = (desalination rate × inlet concentration × flow rate) / electrode area. The TDS and voltage relationship curve of the desalination performance test of the capacitive deionization electrode in Example 9 is as Figure 3 shown. It can be seen from Figure 3 that the desalination rate of the capacitive deionization electrode in Example 9 reached 64.5% after 5 minutes of use, and the maximum adsorption rate was 241 mg / (m 2 ·min).

[0193] (2) Specific surface area, pore volume and resistivity test

[0194] The specific surface area and pore volume (i.e., pore volume) of the capacitive deionization electrodes in Example 8 and Example 9 were respectively tested according to the test method described in GB / T 19587-2017 "Determination of Specific Surface Area of Solid Substances by Gas Adsorption BET Method", and then the AC impedance test data of the capacitive deionization electrodes in Example 8 and Example 9 were tested by the four-probe method. The specific test results are shown in Table 1 below.

[0195] Table 1 Test results of specific surface area, pore volume and resistivity

[0196] Test group <![CDATA[Specific surface area (BET, m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> Resistivity (Ω·cm) Example 8 1106 1.06 0.32 Example 9 987 0.84 0.64

[0197] It can be seen from Table 1 that the capacitive deionization electrodes in Examples 8 to 9 of the present invention all have a relatively large specific surface area (987 - 1106 m 2 / g) and a relatively high pore volume (0.84 - 1.06 cm 3 / g) and a relatively small resistivity (0.32 - 0.64 Ω·cm), which can meet the usage requirements of capacitive deionization electrodes.

[0198] It was found through testing that the various properties of the capacitive deionization electrodes in Examples 10 - 14 are basically equivalent to those in Examples 8 and 9.

[0199] In summary, by introducing an oxidized conductive carbon material with excellent electrical conductivity into the oxidized activated carbon, the present invention can improve the overall electrical conductivity of the capacitive deionization electrode, reduce the resistivity of the capacitive deionization electrode to 0.3 - 0.7 Ω·cm, enable charges to be transferred rapidly in the electrode, and thereby increase the desalination rate of the electrode.

[0200] In addition, the oxidized conductive carbon material and the oxidized activated carbon are connected through hydrogen bonding and physical entanglement, avoiding the agglomeration of the oxidized activated carbon due to electrostatic interaction, improving the dispersibility of the oxidized activated carbon. When preparing the electrode, the usage amount of the binder can be reduced to a certain extent, and the usage amount of the binder does not exceed 10%. The binder is generally a non-conductive material. If the usage amount of the binder is high, it will affect the electrical conductivity of the electrode. If the usage amount of the binder is low, the oxidized conductive carbon material and the porous carbon material are likely to fall off during the preparation of the electrode, affecting the service life and desalination rate of the electrode. Through the physical and chemical entanglement between the oxidized activated carbon and the oxidized conductive carbon material, the present invention can prevent the oxidized conductive carbon material and the porous carbon material from falling off on the premise of reducing the usage amount of the binder.

[0201] The capacitive deionization electrode in the present invention has a micron-sized pore diameter, which has no restrictive effect on the mass transfer and diffusion of hydrated ions. The electrode also has a relatively large specific surface area (700 - 2500 m 2 / g), a relatively large pore volume (0.8 - 1.1 cm 3 / g), and has a relatively large contact area with salt during desalination, improving the desalination rate and desalination effect, enabling the maximum adsorption rate of anions and cations to reach 240 - 330 mg / (m 2 ·min), and the desalination rate is not less than 60% when the working voltage is 1.5 - 2V.

[0202] The above has made a detailed description of the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge scope of those of ordinary skill in the art. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A composition for an electrode, characterized in that: The electrode composition comprises 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).

2. The electrode composition according to claim 1, characterized in that: 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).

3. The electrode composition according to claim 1, characterized in that: At least a portion of the porous carbon material and the oxidatively modified conductive carbon material in the electrode composition are connected via hydrogen bonds and / or physical entanglement.

4. The electrode composition according to any one of claims 1 to 3, characterized in that: The porous carbon material is selected from activated carbon, oxidatively modified activated carbon or a combination thereof.

5. The electrode composition according to any one of claims 1 to 3, characterized in that: The porous carbon material is oxidatively modified activated carbon, and the mass percentage of oxygen in the oxidatively modified activated carbon is 1-10%.

6. The electrode composition according to any one of claims 1 to 3, characterized in that: The mass percentage of oxygen in the oxidatively modified conductive carbon material is 1 to 30%.

7. The electrode composition according to claim 1, characterized in that: The conductive carbon material is selected from at least one of graphene, carbon nanotubes, conductive carbon black and carbon fiber.

8. The electrode composition according to claim 1, characterized in that: The porous carbon material is in granular form; the conductive carbon material is selected from carbon nanotubes, carbon fibers or a combination thereof.

9. The electrode composition according to claim 1, characterized in that: The electrode composition further comprises a solvent; based on the mass percentage of the electrode composition being 100%, the mass percentage of the solvent is 60-95%.

10. The electrode composition according to claim 9, characterized in that: 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.

11. The electrode composition according to claim 1, characterized in that: The binder is selected from at least one of polyacrylic acid, polyethylene glycol, polyvinyl alcohol, polyamic acid, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylonitrile, carboxymethyl cellulose, sodium hydroxymethyl cellulose, and styrene-butadiene rubber.

12. The electrode composition according to claim 1 or 11, characterized in that: The weight average molecular weight of the binder is 5,000 to 2,000,000.

13. The method for preparing the electrode composition according to any one of claims 1 to 12, characterized in that: The following steps are involved: The method is prepared by mixing the oxidatively modified conductive carbon material, the porous carbon material, the binder and an optionally added solvent.

14. The method for preparing the electrode composition according to claim 13, characterized in that: The preparation method comprises the following steps: 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; S2: Mixing the binder dispersion and the conductive dispersion to prepare the electrode composition.

15. A capacitive deionization electrode, characterized in that: It comprises an electrode layer; the raw material for preparing the electrode layer is the electrode composition according to any one of claims 1 to 12.

16. The capacitive deionization electrode according to claim 15, characterized in that: The capacitive deionization electrode has at least one of the following features: (a) The maximum adsorption rate of anions and cations is 200-400 mg / (m 2 ·min); (b) Specific surface area is 700 to 2500 m 2 / g; (c) Pore volume is 0.8 to 1.1 cm 3 / g; (d) Resistivity is 0.3 to 0.7 Ω·cm; (e) The desalination rate is not less than 60% when the operating voltage is 1.5-2V.

17. A water treatment device, characterized in that: The capacitor deionization electrode comprises the capacitor deionization electrode as described in any one of claims 15 to 16.

18. The water treatment equipment according to claim 17, characterized in that: The water treatment equipment includes water purification equipment, water desalination equipment and water softening equipment.

19. 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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