A layered titanium dioxide-based electrode material, and a preparation method and application thereof

Abstract

The present invention discloses a layered titanium dioxide-based electrode material and its preparation method and application, belonging to the technical field of titanium-based negative electrode materials for sodium ion batteries. The above-mentioned preparation method is as follows: layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 was acidified and filtered and dried to obtain layered titanate H 1.07 Ti 1.73 O4 powder, followed by layered titanate H 1.07 Ti 1.73 O4 powder is mixed with an expander and expanded to produce expanded layered titanic acid. A carbon precursor solution is then added and stirred, and then allowed to stand to produce a colloidal precursor. The colloidal precursor is hydrothermally treated to produce an intermediate electrode material. The intermediate electrode material is then washed with water and carbonized at high temperature to produce a layered titanium dioxide-based electrode material. The resulting material features alternating titanium dioxide and carbon layers, ensuring full contact between the carbon material and the TiO2, maximizing electrical conductivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of titanium-based negative electrode materials for sodium ion batteries, and particularly relates to a layered titanium dioxide-based electrode material and a preparation method and application thereof. BACKGROUND

[0002] Sodium ion batteries have shown great potential to replace lithium ion batteries in the energy storage field due to their low cost and high reserves. The morphology and composition design of the negative electrode material, as a key component of sodium ion batteries, are crucial to meet the requirements of high specific capacity and high-rate charge-discharge, which is the key to building high-performance sodium batteries and the key to realizing the commercialization of sodium batteries. Among the alternative negative electrode materials, titanium-based negative electrode materials are considered an ideal choice for sodium ion battery negative electrode materials due to their low sodium potential, low cost, non-toxicity, and good lattice stability.

[0003] Titanium-based negative electrode materials are an important category of sodium ion battery negative electrode materials, mainly including different crystal forms of titanium dioxide (such as anatase, rutile, and brookite) and titanates (such as lithium titanate and sodium titanate). Among them, anatase titanium dioxide is considered to have great potential to achieve high specific capacity and high-rate performance due to its unique crystal structure and excellent electrochemical performance. However, the application of this material is still limited by two key factors. First, the band gap of anatase titanium dioxide is relatively large (about 3.2 eV), which makes its electronic conductivity low, affecting the charge transfer efficiency of the electrode material. Second, micron-sized anatase titanium dioxide particles, when used as a negative electrode material for sodium ion batteries, can only achieve shallow surface reactions of about 5 nm in depth during the sodium insertion process, which is significantly smaller than the overall size of micron-sized anatase titanium dioxide particles, resulting in limited diffusion paths for sodium ions, which in turn restricts the full play of the sodium ion storage capacity of anatase titanium dioxide. Currently, to address the shortcomings of poor electronic conductivity and limited diffusion paths for sodium ions in layered anatase titanium dioxide, various improvement strategies have been proposed, including the compounding of titanium dioxide with high-conductivity materials (such as carbon), the design of titanium dioxide nanostructures, and the design of layered structures.

[0004] The main improvement direction of the above composite strategy is to deeply composite the layered anatase titanium dioxide with various two-dimensional materials, organic and inorganic materials, etc. through structural design. This composite method is widely used in the design of TiO2 type energy storage materials, and the electrochemical performance is optimized due to the significant improvement of the conductivity. For example, titanium dioxide is compounded with high-conductivity materials (such as carbon) to improve the conductivity of layered anatase and the diffusion path of sodium ions. The method is generally to prepare TiO2 / C composite material by compounding TiO2 with high-conductivity materials such as graphene, carbon nanotubes and carbon dots. The introduction of carbon in the TiO2 / C composite material is to compound the pre-prepared carbon-based material with the finished layered anatase, spherical anatase, etc. through hydrothermal or electrostatic adsorption. However, in the TiO2 / C composite material obtained by this method, although the micron-sized anatase TiO2 is coated with carbon material, the carbon material and the anatase TiO2 do not achieve full contact, so it is difficult to maximize the improvement of the conductivity. In the design of titanium dioxide nanostructure, it is reported that nanometerization of finished layered anatase through ball milling and other methods to reduce the particle size of anatase titanium dioxide, or compounding small-sized anatase with other conductive materials by electrospinning technology, can improve the sodium ion diffusion capacity to a certain extent. However, the above-mentioned method of simply relying on size reduction has obvious disadvantages: on the one hand, the related preparation process is complicated, which increases the production cost and operation difficulty; on the other hand, excessive reduction of particle size will cause the specific surface area to increase sharply, thereby causing too many side reactions, which will significantly affect the stability of the electrode, which is not conducive to its actual application and long-term performance. In the design of layered anode with two kinds of nanosheet layers arranged alternately to improve the electronic conductivity and capacity, the traditional design strategy can be divided into "bottom-up" and "top-down". The bottom-up composite strategy includes layer-by-layer assembly, atomic layer deposition / molecular layer deposition, hydrothermal method and anti-solvent diffusion method; the top-down composite strategy includes electrochemical intercalation method and chemical intercalation method. However, the traditional bottom-up structural design strategy will inevitably cause multi-layer stacking, pillar supporting and agglomeration, and the top-down strategy is difficult to control the degree of molecular intercalation, which easily leads to the distortion of the crystal structure of the main material in the intercalation process. The structure obtained by the above two design strategies contains a large number of defects, which will cause a large amount of consumption of electrolyte when applied in batteries, and cannot achieve the optimal capacity.

[0005] In summary, to solve the intrinsic performance defects of poor electronic conductivity and limited sodium ion diffusion path of anatase titanium dioxide material as a negative electrode material of a sodium ion battery, the traditional modification strategies have the following limitations: 1) the deficiency of composite high-conductivity materials (such as carbon): the interface contact is insufficient, and the electronic conductivity is difficult to maximize; 2) the disadvantages of nanostructure design: the preparation process is complex, and the specific surface area is too large to cause side reactions; 3) the problems of layered structure design: the bottom-up strategy is prone to multi-layer stacking and pillar-supported aggregation, and the top-down strategy is prone to lattice distortion of the main material. SUMMARY

[0006] In order to overcome the above-mentioned defects of the prior art, the purpose of the present application is to provide a layered titanium dioxide-based electrode material and a preparation method and application thereof, so as to solve the technical problems of insufficient interface contact, difficult to maximize the electronic conductivity, complex preparation process, too large specific surface area to cause side reactions, prone to multi-layer stacking and pillar-supported aggregation in the bottom-up strategy, and prone to lattice distortion of the main material in the top-down strategy.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] The first aspect of the present application provides a preparation method of a layered titanium dioxide-based electrode material, comprising the following steps: acidizing and filtering and drying a layered alkali titanate K 0.8 Li 0.27 Ti 1.73 O4 in sequence until layered titanate H 1.07 Ti 1.73 O4 powder is obtained, then the layered titanate H 1.07 Ti 1.73 O4 powder is mixed with an expanding agent for expansion treatment to obtain expanded layered titanate, a carbon precursor solution is added to the expanded layered titanate and stirred, the carbon is inserted between adjacent layers of the expanded layered titanate in the stirring process, and then a gelatinous precursor is obtained by standing treatment; the gelatinous precursor is subjected to hydrothermal treatment to obtain an intermediate electrode material, the intermediate electrode material is washed with water, and then high-temperature calcination and carbonization treatment is performed to obtain a layered titanium dioxide-based electrode material.

[0009] In an embodiment, the acid solution used in the acidizing treatment is a hydrochloric acid solution or a nitric acid solution; the concentration of the acid solution is 0.5M-1M; and the use amount ratio of the layered alkali titanate K 0.8 Li 0.27 Ti 1.73 O4 to the acid solution is 1g-10g:100mL-2000mL.

[0010] In an embodiment, the swelling agent is any one of dimethylaminoethanol, methylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ethanolamine and cetyltrimethylammonium salt; and the concentration of the swelling agent is 0.02M-2M.

[0011] In an embodiment, the layered titanic acid H 1.07 Ti 1.73 The ratio of the amount of the layered titanic acid H

[0012] In an embodiment, the layered titanic acid H 1.07 Ti 1.73 The mixing time of the layered titanic acid H

[0013] In an embodiment, the carbon precursor in the carbon precursor solution is any one of glucose, cellulose, polyethylene glycol and sodium citrate; and the concentration of the carbon precursor solution is 0.005M-0.5M.

[0014] In an embodiment, the ratio of the amount of the carbon precursor solution to the swollen layered titanic acid is 50mL-500mL:0.1g-1g.

[0015] In an embodiment, the stirring time is 0.5h-24h; the standing time is 12h-24h; the temperature of the hydrothermal treatment is 160℃-180℃, and the time of the hydrothermal treatment is 8h-18h; the high-temperature calcination carbonization treatment is carried out in an argon atmosphere, the temperature of the high-temperature calcination carbonization treatment is 550℃-650℃, and the time of the high-temperature calcination carbonization treatment is 3h-5h.

[0016] The second aspect of the present application provides a layered titanic acid-based electrode material prepared by the preparation method of the layered titanic acid-based electrode material, and the layered titanic acid-based electrode material has a TiO2 / C periodic layered structure formed by the alternation of the titanic acid layer and the carbon layer.

[0017] The third aspect of the present application provides an application of the layered titanic acid-based electrode material as a negative electrode material in a sodium ion battery.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] The present application provides a preparation method of a layered titanic acid-based electrode material. 1.07 Ti 1.73In the gap between adjacent layers of O4, a TiO2 / C electrode material with a periodic structure of alternating TiO2 layers and carbon layers is prepared by subsequent high-temperature calcination and carbonization treatment. Specifically, the preparation method first performs acidification treatment on layered alkali titanate K 0.8 Li 0.27 Ti 1.73 O4 to obtain layered titanate H 1.07 Ti 1.73 O4, and removes residual acid and water by suction filtration and drying to obtain layered titanate H 1.07 Ti 1.73 O4 powder. Subsequently, by introducing an expanding agent into the layered titanate H 1.07 Ti 1.73 O4 powder to weaken the interlayer electrostatic interaction and van der Waals force, an open interlayer channel that can accommodate carbon source molecules is formed to obtain expanded layered titanate. Then, by adding a carbon precursor solution and stirring, the carbon precursor molecules are uniformly adsorbed on the expanded layered titanate H 1.07 Ti 1.73 O4 between adjacent layers in the form of a monolayer or oligomer to obtain a gel-like precursor. Finally, the obtained gel-like precursor is converted into a nanoscale amorphous carbon interlayer after hydrothermal treatment and high-temperature calcination and carbonization, and finally forms a layered titania-based electrode material. The existence form of carbon in the layered titania-based electrode material with a periodic TiO2 / C structure obtained by the above four steps of expanding layered titanate, carbon source intercalation, hydrothermal polymerization, and high-temperature calcination and carbonization can maximize the electronic conductivity, thereby improving the electronic conductivity of the anatase titania-based electrode material. By expanding the layered titanate first, the interlayer gap is expanded during the expansion process, avoiding the problem of pore blockage caused by the stacking and agglomeration of multi-layer nanosheets in the traditional bottom-up method. The carbon source is introduced by a mild intercalation method, avoiding damage to the host lattice by strong external force or chemical etching, ensuring the integrity of the layered structure of titanium dioxide, and avoiding the lattice distortion problem caused by the top-down method. By uniformly inserting the carbon precursor into the interlayer gap after expansion, a carbon layer closely adhered to the titanium dioxide layer is formed after high-temperature calcination and carbonization, optimizing the interface contact of the composite carbon, solving the problem of insufficient interface contact in traditional carbon composites, and improving the electronic conduction efficiency. And the layered structure design avoids the excessive dispersion of nanoparticles, controls the specific surface area within a reasonable range, reduces the invalid contact between the electrolyte and the active material, suppresses the side reaction, and balances the specific surface area and side reaction of the nanostructure. Through the expansion-intercalation process, the sodium ion diffusion path is shortened, the material capacity potential is developed, and the rate performance is improved. In summary, the preparation method effectively solves the problems of poor electronic conductivity and limited sodium ion diffusion path of existing layered anatase titania-based materials as negative electrode materials for sodium ion batteries, significantly improves the electronic conductivity of the layered titania-based electrode material, thereby improving the electronic conductivity.

[0020] Another aspect of the present invention provides a layered titanium dioxide-based electrode material prepared using the above-mentioned preparation method. This material has a TiO2 / C periodic layered structure formed by alternating titanium dioxide layers and carbon layers. The carbon material therein has excellent electronic conductivity. The carbon layers act as "electron transport bridges" to connect adjacent TiO2 nanosheets, forming a continuous conductive network. This reduces the high impedance faced by electrons transferring between the TiO2 nanosheets, allowing for full contact between the carbon material and the TiO2, significantly improving the overall electronic conductivity of the electrode. Furthermore, the carbon present between the TiO2 layers provides a better sodium ion conductive path, thereby improving sodium ion conductivity, fully realizing the material's capacity potential, and significantly enhancing its rate performance, maintaining a high actual capacity even at high currents (high rates). The alternatingly stacked layered titanium dioxide-based electrode material has a small specific surface area, effectively reducing side reactions. The carbon layer in this material acts as an "electron highway" that runs through the entire electrode material, compensating for the insulation of titanium dioxide and significantly reducing the charge transfer resistance; the layered structure provides a one-dimensional ion transfer channel, effectively shortening the sodium ion diffusion path; the interlayer carbon and titanium dioxide form a chemical bond through high-temperature calcination, rather than a simple physical mixing, enhancing the interfacial electron transfer ability and maximizing the conductivity; the structural stability of the material has been improved, and the layered skeleton inhibits the volume expansion of titanium dioxide during charging and discharging, avoiding structural collapse and improving the cycle life.

[0021] The present invention also provides the use of the above-mentioned layered titanium dioxide-based electrode material as a negative electrode material in a sodium-ion battery. When used as a negative electrode material in a sodium-ion battery, the low specific surface area of ​​the layered structure and the stable carbon coating inhibit side reactions and interfacial impedance, reducing the probability of electrolyte penetration into the active material and reducing interfacial side reactions. The carbon layer also reduces the high impedance faced by electrons transferring between TiO2 nanosheets, significantly improving the overall electronic conductivity of the electrode. Secondly, the periodic layered structure achieves ion / electron transport decoupling—sodium ions diffuse rapidly along the interlayer channels, while electrons conduct rapidly through the carbon layer, thereby improving the battery capacity, rate capability, and cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the layered titanium dioxide-based electrode material prepared in Example 1 of the present invention;

[0023] Figure 2 The layered titanate H prepared in Example 1 of the present invention 1.07 Ti 1.73 XRD pattern of O4 powder;

[0024] Figure 3 The layered titanate H prepared in Example 1 of the present invention 1.07 Ti 1.73SEM image of O4 powder;

[0025] Figure 4 Optical microscope image of the expanded layered titanate prepared for Example 1 of the present application;

[0026] Figure 5 SEM image of the layered titanium dioxide-based electrode material prepared for Example 1 of the present application;

[0027] Figure 6 Element mapping image of the layered titanium dioxide-based electrode material prepared for Example 1 of the present application;

[0028] Figure 7 Rate performance test image of the layered titanium dioxide-based electrode material prepared for Example 1 of the present application, and the titanium dioxide-based electrode materials prepared for Comparative Example 1 and Comparative Example 6;

[0029] Figure 8 Constant current charge-discharge capacity test and long cycle stability test image of the layered titanium dioxide-based electrode material prepared for Example 1 of the present application, and the titanium dioxide-based electrode materials prepared for Comparative Example 1 and Comparative Example 6. DETAILED DESCRIPTION

[0030] To enable persons skilled in the art to understand the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings to those skilled in the art of the present application, and in the event of conflict, the definitions in the present specification shall prevail.

[0031] Herein, all features defined in the form of numerical ranges or percentage ranges such as numerical values, quantities, contents and concentrations are for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0032] Herein, for the sake of brevity, all possible combinations of the technical features in each embodiment or example are not described. Therefore, as long as the combinations of the technical features do not contradict each other, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope of the present specification.

[0033] The present application provides a layered titanium dioxide-based electrode material, and a preparation method and application thereof.

[0034] In one aspect, a preparation method of a layered titanium dioxide-based electrode material is provided, which comprises the following steps: subjecting a layered alkali titanate K 0.8 Li0.27 Ti 1.73 O4 is acidified and filtered and dried in sequence until layered titanate H 1.07 Ti 1.73 O4 powder, followed by layered titanate H 1.07 Ti 1.73 O4 powder is mixed with an expander and expanded to obtain expanded layered titanic acid. A carbon precursor solution is then added to the expanded layered titanic acid and stirred. During the stirring process, carbon is inserted between adjacent layers of the expanded layered titanic acid. The mixture is then allowed to stand to obtain a colloidal precursor. The colloidal precursor is hydrothermally treated to obtain an intermediate electrode material. The intermediate electrode material is washed with water and then subjected to high-temperature calcination and carbonization treatment to obtain a layered titanium dioxide-based electrode material.

[0035] More specifically, the method for preparing the layered titanium dioxide-based electrode material comprises the following steps:

[0036] S1: To layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is added to an acid solution with a concentration of 0.5M~1M for acidification, and then filtered and dried until layered titanate H 1.07 Ti 1.73 O4 powder; wherein, layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 The dosage ratio of O4 to acid solution is 1g~10g:100mL~2000mL.

[0037] S2: Layered titanate H 1.07 Ti 1.73 O4 powder is added to an expander with a concentration of 0.02M~2M and mixed for 30min~90min to expand to obtain expanded layered titanic acid. Immediately thereafter, a carbon precursor solution with a concentration of 0.005M~0.5M is added to the expanded layered titanic acid and stirred for 0.5h~24h. During the stirring process, carbon is inserted between adjacent layers of the expanded layered titanic acid. The product is then allowed to stand for 12h~24h to obtain a colloidal precursor. 1.07 Ti 1.73 The dosage ratio of O4 powder to expander is 0.1g~1g:50mL~500mL; the dosage ratio of carbon precursor solution to expanded layered titanic acid is 50mL~500mL:0.1g~1g.

[0038] S3: The colloidal precursor is subjected to a hydrothermal treatment at a temperature of 160°C to 180°C for 8h to 18h to obtain an intermediate electrode material. After the intermediate electrode material is washed with water, it is subjected to a high-temperature calcination and carbonization treatment at a temperature of 550°C to 650°C in an argon atmosphere tubular furnace for 3h to 5h to obtain a layered titanium dioxide-based electrode material.

[0039] Preferably, the acid solution used in the acidification treatment is a hydrochloric acid solution or a nitric acid solution.

[0040] Preferably, the expander is any one of dimethylaminoethanol, methylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ethanolamine and cetyltrimethylammonium salt.

[0041] Preferably, the carbon precursor in the carbon precursor solution is any one of glucose, cellulose, polyethylene glycol and sodium citrate.

[0042] In the above preparation method, the solvents in the acid solution, the expansion agent and the carbon precursor solution are all pure water.

[0043] See also Figure 1 On the one hand, a layered titanium dioxide-based electrode material prepared by the above-mentioned preparation method is provided, which has a TiO2 / C periodic layered structure formed by alternating titanium dioxide layers and carbon layers.

[0044] On the other hand, the invention also provides the use of the layered titanium dioxide-based electrode material prepared by the above preparation method as a negative electrode material in a sodium ion battery.

[0045] The application process of the above-mentioned layered titanium dioxide-based electrode material as a negative electrode material in sodium ion batteries is as follows:

[0046] The layered titanium dioxide-based electrode material is ground and compounded with a conductive agent and a binder in a mass ratio of 7:2:1, and then dried at a temperature of 60°C to 80°C to obtain a layered titanium dioxide-based electrode sheet, which is used as the negative electrode of a sodium ion battery.

[0047] In summary, compared with traditional improvement strategies, the present invention provides a layered titanium dioxide-based electrode material, a preparation method and an application thereof. In the layered titanium dioxide-based electrode material, the titanium dioxide layer and the carbon layer are alternately arranged in a periodic structure, so that the carbon material is in full contact with TiO2, thereby maximizing the improvement of conductivity. The preparation process of the material is simple, and the obtained alternatingly stacked layered titanium dioxide-based electrode material has a smaller specific surface area, thereby effectively reducing side reactions. In addition, the TiO2 lattice remains intact during the preparation process, solving the problem of multiple stacking in the bottom-up composite strategy, and after the conductive carbon is inserted, the anatase lattice of the main material is highly maintained, avoiding the phenomenon of lattice distortion of the main material caused by the intercalation process in the top-down composite strategy.

[0048] The application will be further described in connection with specific embodiments. It will be understood that these embodiments are intended to illustrate the application and not to limit its scope. Furthermore, it will be understood that those skilled in the art can make various modifications or alterations to the application upon reading and understanding the teachings of the application, and such equivalent forms are also intended to fall within the scope of the appended claims.

[0049] The following examples use the apparatuses and devices that are conventional in the art. The experimental methods in the following examples, unless otherwise specified, are generally carried out according to the conventional conditions, or according to the conditions recommended by the manufacturers. The following examples use various raw materials, unless otherwise specified, all use conventional commercially available products, and the specifications are conventional specifications in the art. In the specification of the application and the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0050] The assembly process of the sodium-ion battery using the layered titanium dioxide-based electrode sheet as the negative electrode is as follows:

[0051] The battery device assembled in the examples is a CR2032 type button-shaped half battery. Among them, the positive shell and the negative shell are 2032 battery shells, the separator is a 16 mm glass fiber separator, the electrolyte is 1.0 M NaPF6 in EC: DMC = 1:1 Vol% with 5.0% FEC, and the sodium sheet is a 14 mm sodium sheet that has been cut.

[0052] The assembly sequence is a reverse assembly method. The layered titanium dioxide-based electrode sheet is placed at the center position of the negative shell, 75 μL of electrolyte is added, the glass fiber separator is buckled, 75 μL of electrolyte is added, then the aluminum foil of the sodium sheet is buckled upwards and placed at the center position of the separator, then the gasket and the spring are placed, and finally the positive shell is buckled tightly. The entire battery is clamped with an insulating tweezer and placed on the button cell sealing machine mold for sealing. A complete half battery assembly is completed.

[0053] The titanium dioxide-based electrode materials prepared in Comparative Examples 1 to 6 and the layered titanium dioxide-based electrode materials prepared in Examples 1 to 9 are subjected to the same processing procedure when preparing the corresponding electrode sheets, and are all subjected to drying treatment at a temperature of 80°C. The above electrode sheets are used as negative electrode materials, and sodium-ion batteries are prepared based on the same assembly process, and are uniformly subjected to electrochemical performance tests. The specific electrochemical performance test items include rate performance test, constant current charge and discharge capacity test, and long cycle stability test.

[0054] Example 1

[0055] The embodiment provides a preparation method of a layered titanium dioxide-based electrode material, which comprises the following steps:

[0056] Step 1: add 5g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 500 mL of 0.5 M hydrochloric acid solution was added to the O4 for acidification, and then filtered and dried to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0057] Step 2: 0.1g layered titanate H 1.07 Ti 1.73 O4 powder was added to 100 mL of 0.2 M dimethylaminoethanol solution and mixed for 60 min to obtain expanded layered titanic acid.

[0058] Step 3: Immediately add 100 mL of 0.2 M glucose solution to 0.1 g of expanded layered titanic acid and stir for 12 h, then let it stand for 12 h to obtain a colloidal precursor.

[0059] Step 4: The colloidal precursor is hydrothermally treated at 160°C for 18 hours to obtain an intermediate electrode material. After washing the intermediate electrode material with water, it is subjected to high-temperature calcination and carbonization treatment at 550°C for 3 hours in an argon atmosphere tubular furnace to obtain a layered titanium dioxide-based electrode material.

[0060] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method, such as Figure 1 The titanium dioxide layers and carbon layers in this material are stacked alternately to form a TiO2 / C periodic layered structure.

[0061] like Figure 2 As shown, the layered titanate H prepared in this embodiment 1.07 Ti 1.73 XRD pattern of O4 powder, layered titanate H 1.07 Ti 1.73 O4 crystal has an obvious sharp peak at 2θ=9.62°, which is the characteristic peak of (020) crystal plane. The calculated (020) crystal plane spacing is 0.919nm. The existence of this characteristic peak confirms that layered titanate H 1.07 Ti 1.73 O4 crystals have a layered structure. Figure 3 As shown, the layered titanate H prepared in this embodiment 1.07 Ti 1.73 The SEM image of O4 powder clearly shows the layered titanate H 1.07 Ti 1.73 O4 crystals have a layered structure. Figure 4 The expanded layered titanate H prepared in this embodiment after expansion treatment with an expansion agent 1.07 Ti 1.73The optical microscope image of O4 shows that the layered titanate H 1.07 Ti 1.73 O4 crystal expands into a long strip. As Figure 5 The SEM image of the layered titanium dioxide-based electrode material prepared in this embodiment shows that the titanium dioxide layers and carbon layers in the material are alternately stacked. As Figure 6 The element mapping image of the layered titanium dioxide-based electrode material (TiO2 / C electrode material) prepared in this embodiment shows that the Ti, C, and O elements in the material are uniformly distributed, which can further illustrate that the titanium dioxide layers and carbon layers are alternately stacked.

[0062] As Figure 7 and Figure 8 shown, the rate performance test, constant current charge and discharge capacity test, and long cycle stability test found that the layered titanium dioxide-based electrode sheet further prepared from the layered titanium dioxide-based electrode material prepared in this embodiment can obtain a specific capacity of 275 mAh / g at a current density of 0.05 A / g, a specific capacity of 252 mAh / g at a current density of 0.1 A / g, a specific capacity of 239 mAh / g at a current density of 0.2 A / g, a specific capacity of 211 mAh / g at a current density of 0.5 A / g, a specific capacity of 191 mAh / g at a current density of 1 A / g, a specific capacity of 154 mAh / g at a current density of 2 A / g, and a specific capacity of 126 mAh / g at a current density of 5 A / g, and the capacity retention rate is 90% after 500 cycles at a current density of 1 A / g.

[0063] Example 2

[0064] This embodiment provides a preparation method of a layered titanium dioxide-based electrode material, comprising the following steps:

[0065] Step one, 1 g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is added with 100 mL of 0.5 M nitric acid solution for acidification treatment, and then subjected to suction filtration and drying treatment to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0066] Step two, 0.1 g of layered titanate H 1.07 Ti 1.73 O4 powder is added to 50 mL of 0.02 M methylamine solution and mixed for 60 min to obtain expanded layered titanate.

[0067] Step three, 50 mL of cellulose solution with a concentration of 0.005 M was immediately added to 0.1 g of the expanded layered titanate and stirred for 12 h, and then left to stand for 12 h to obtain a gel-like precursor.

[0068] Step four, the gel-like precursor was subjected to hydrothermal treatment at a temperature of 160 ℃ for 8 h to obtain an intermediate electrode material, which was washed with water and subjected to high-temperature calcination and carbonization treatment in a tube furnace under an argon atmosphere at a temperature of 550 ℃ for 5 h to obtain a layered titanium dioxide-based electrode material.

[0069] Another aspect of the embodiment also provides a layered titanium dioxide-based electrode material prepared by the preparation method.

[0070] It is found through rate performance testing, constant-current charge and discharge capacity testing, and long cycle stability testing that the layered titanium dioxide-based electrode sheet further prepared from the layered titanium dioxide-based electrode material prepared in the embodiment can obtain a specific capacity of 190 mAh / g at a current density of 0.1 A / g, and a specific capacity of 65 mAh / g at a current density of 5 A / g, and a capacity retention rate of 90% after 500 cycles at a current density of 1 A / g.

[0071] Embodiment 3

[0072] The embodiment provides a preparation method of a layered titanium dioxide-based electrode material, which comprises the following steps.

[0073] Step one, 10 g of layered alkali titanate K 0.8 Li 0.27 Ti 1.73 O4 was added with 2000 mL of hydrochloric acid solution with a concentration of 0.5 M for acidification treatment, and then subjected to suction filtration and drying treatment to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0074] Step two, 1 g of layered titanate H 1.07 Ti 1.73 O4 powder was added to 500 mL of tetramethylammonium hydroxide solution with a concentration of 2 M and mixed for 50 min to obtain expanded layered titanate.

[0075] Step three, 500 mL of polyethylene glycol solution with a concentration of 0.5 M was immediately added to 1 g of the expanded layered titanate and stirred for 12 h, and then left to stand for 12 h to obtain a gel-like precursor.

[0076] Step four, the gel-like precursor was subjected to hydrothermal treatment at a temperature of 180 ℃ for 8 h to obtain an intermediate electrode material, which was washed with water and subjected to high-temperature calcination and carbonization treatment in a tube furnace under an argon atmosphere at a temperature of 650 ℃ for 5 h to obtain a layered titanium dioxide-based electrode material.

[0077] The embodiment further provides the layered titanium dioxide-based electrode material prepared by the preparation method.

[0078] The layered titanium dioxide-based electrode material prepared by the preparation method has a specific capacity of 174 mAh / g at a current density of 0.1 A / g, a specific capacity of 56 mAh / g at a current density of 5 A / g, and a capacity retention rate of 90% after 500 cycles at a current density of 1 A / g.

[0079] Embodiment 4

[0080] The embodiment further provides the layered titanium dioxide-based electrode material prepared by the preparation method.

[0081] Step one, 1 g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is added with 2000 mL of a 1M nitric acid solution for acidification treatment, and then subjected to suction filtration and drying treatment to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0082] Step two, 0.1 g of layered titanate H 1.07 Ti 1.73 O4 powder is added to 500 mL of a 0.02M ethanolamine solution and mixed for 40 min to obtain expanded layered titanate.

[0083] Step three, 500 mL of a 0.005M sodium citrate solution is immediately added to 0.1 g of the expanded layered titanate and stirred for 0.5 h, and then left to stand for 24 h to obtain a gel-like precursor.

[0084] Step four, the gel-like precursor is subjected to hydrothermal treatment at a temperature of 180°C for 18 h to obtain an intermediate electrode material, which is washed with water and then subjected to high-temperature calcination and carbonization treatment in an argon atmosphere tube furnace at a temperature of 650°C for 3 h to obtain a layered titanium dioxide-based electrode material.

[0085] The embodiment further provides the layered titanium dioxide-based electrode material prepared by the preparation method.

[0086] The layered titanium dioxide-based electrode material prepared in this embodiment is further prepared into a layered titanium dioxide-based electrode sheet, which can obtain a specific capacity of 180 mAh / g at a current density of 0.1 A / g, and a specific capacity of 62 mAh / g at a current density of 5 A / g, and the capacity retention rate is 90% after 500 cycles at a current density of 1 A / g.

[0087] Example 5

[0088] This embodiment provides a preparation method of a layered titanium dioxide-based electrode material, which comprises the following steps:

[0089] Step one, 10 g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is added with 100 mL of 1M hydrochloric acid solution for acidification treatment, and then subjected to suction filtration and drying treatment to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0090] Step two, 1 g of layered titanate H 1.07 Ti 1.73 O4 powder is added to 50 mL of 2M hexadecyltrimethylammonium salt solution and mixed for 30 min to obtain expanded layered titanate.

[0091] Step three, 50 mL of 0.5M glucose solution is immediately added to 1 g of expanded layered titanate and stirred for 24 h, and then left to stand for 12 h to obtain a colloidal precursor.

[0092] Step four is the same as step four of example 1, and a layered titanium dioxide-based electrode material is obtained.

[0093] This embodiment further provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0094] The layered titanium dioxide-based electrode material prepared in this embodiment is further prepared into a layered titanium dioxide-based electrode sheet, which can obtain a specific capacity of 142 mAh / g at a current density of 0.1 A / g, and a specific capacity of 25 mAh / g at a current density of 5 A / g, and the capacity retention rate is 90% after 500 cycles at a current density of 1 A / g.

[0095] Example 6

[0096] This embodiment provides a preparation method of a layered titanium dioxide-based electrode material, which comprises the following steps:

[0097] Step one, 1g layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is added to 100mL of 0.5M nitric acid solution for acidification treatment, and then filtered and dried to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0098] Step two, 1g layered titanate H 1.07 Ti 1.73 O4 powder is added to 500mL of 0.02M dimethylamino ethanol solution and mixed for 70min to obtain expanded layered titanate.

[0099] Step three, 50mL of 0.5M cellulose solution is immediately added to 1g of expanded layered titanate and stirred for 12h, and then left to stand for 12h to obtain a gel-like precursor.

[0100] Step four is the same as step four of example 1 to obtain layered titanium dioxide-based electrode material.

[0101] Another aspect of the present embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0102] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it is found that the layered titanium dioxide-based electrode sheet further prepared from the layered titanium dioxide-based electrode material prepared in the present embodiment can obtain a specific capacity of 162Ah / g at a current density of 0.1A / g, and a specific capacity of 33mAh / g at a current density of 5A / g, and a capacity retention rate of 90% after 500 cycles at a current density of 1A / g.

[0103] Example 7

[0104] The present embodiment provides a preparation method of a layered titanium dioxide-based electrode material, comprising the following steps:

[0105] Step one, 10g layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is added to 2000mL of 1M nitric acid solution for acidification treatment, and then filtered and dried to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0106] Step two, 0.1g layered titanate H 1.07 Ti 1.73O4 powder is added into 50 mL of methylamine solution with a concentration of 2 M and mixed for 80 min to obtain expanded layered titanate.

[0107] Step three, 500 mL of polyethylene glycol solution with a concentration of 0.005 M is immediately added into 0.1 g of expanded layered titanate and stirred for 12 h, and then left to stand for 12 h to obtain a gel-like precursor.

[0108] Step four is the same as that of Example 1, and a layered titanium dioxide-based electrode material is obtained.

[0109] In another aspect, the layered titanium dioxide-based electrode material prepared by the preparation method is also provided.

[0110] It is found through rate performance test, constant current charge and discharge capacity test and long cycle stability test that the layered titanium dioxide-based electrode sheet further prepared from the layered titanium dioxide-based electrode material prepared in the example can obtain a specific capacity of 161 mAh / g at a current density of 0.1 A / g, and a specific capacity of 48 mAh / g at a current density of 5 A / g, and a capacity retention rate of 90% after 500 cycles at a current density of 1 A / g.

[0111] Example 8

[0112] In one aspect, the present example provides a preparation method of a layered titanium dioxide-based electrode material, comprising the following steps:

[0113] Step one, 10 g of layered alkali titanate K 0.8 Li 0.27 Ti 1.73 O4 is added into 2000 mL of hydrochloric acid solution with a concentration of 1 M for acidification treatment, and then subjected to suction filtration and drying treatment to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0114] Step two, 0.1 g of layered titanate H 1.07 Ti 1.73 O4 powder is added into 500 mL of tetramethylammonium hydroxide solution with a concentration of 0.02 M and mixed for 60 min to obtain expanded layered titanate.

[0115] Step three, 500 mL of sodium citrate solution with a concentration of 0.005 M is immediately added into 0.1 g of expanded layered titanate and stirred for 12 h, and then left to stand for 12 h to obtain a gel-like precursor.

[0116] Step four, the hydrothermal treatment of the gel precursor at a temperature of 160℃ for 18h obtained intermediate electrode material, water washing the intermediate electrode material in the argon atmosphere tube furnace at a temperature of 650℃ for 3h high temperature calcination carbonization treatment obtained layered titanium dioxide-based electrode material.

[0117] The embodiment further provides the layered titanium dioxide-based electrode material prepared by the preparation method.

[0118] The capacity test and long cycle stability test found that the layered titanium dioxide-based electrode sheet prepared by the layered titanium dioxide-based electrode material further prepared by the embodiment can obtain a specific capacity of 131mAh / g at a current density of 0.1A / g, and a specific capacity of 40mAh / g at a current density of 5A / g, and a capacity retention rate of 90% after 500 cycles at a current density of 1A / g.

[0119] Embodiment 9

[0120] The embodiment provides a preparation method of a layered titanium dioxide-based electrode material, comprising the following steps:

[0121] Step one, 1g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is added to 100mL of 0.5M nitric acid solution for acidification treatment, and then subjected to filtration and drying treatment to obtain layered titanate H 1.07 Ti 1.73 O4 powder.

[0122] Step two, 1g of layered titanate H 1.07 Ti 1.73 O4 powder is added to 500mL of 2M tetraethylammonium hydroxide solution and mixed for 90min to obtain expanded layered titanate.

[0123] Step three, 50mL of 0.5M sodium citrate solution is immediately added to 1g of expanded layered titanate and stirred for 12h, and then left to stand for 12h to obtain a gel precursor.

[0124] Step four, the hydrothermal treatment of the gel precursor at a temperature of 160℃ for 18h obtained intermediate electrode material, water washing the intermediate electrode material in the argon atmosphere tube furnace at a temperature of 650℃ for 3h high temperature calcination carbonization treatment obtained layered titanium dioxide-based electrode material.

[0125] The embodiment further provides the layered titanium dioxide-based electrode material prepared by the preparation method.

[0126] The layered titanium dioxide-based electrode material prepared in the embodiment is further prepared into a layered titanium dioxide-based electrode sheet, which can obtain a specific capacity of 154 mAh / g at a current density of 0.1 A / g, and can obtain a specific capacity of 32 mAh / g at a current density of 5 A / g, and has a capacity retention rate of 90% after 500 cycles at a current density of 1 A / g.

[0127] Comparative Example 1

[0128] The comparative example provides a preparation method of a titanium dioxide-based electrode material, which comprises the following steps:

[0129] Step 1: 5 g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is added with 500 mL of a hydrochloric acid solution with a concentration of 0.5 M for acidification treatment, and then subjected to suction filtration and drying treatment to obtain layered titanic acid H 1.07 Ti 1.73 O4 powder.

[0130] Step 2: 100 mL of a glucose solution with a concentration of 0.2 M is added to 0.1 g of the layered titanic acid H 1.07 Ti 1.73 O4 powder, stirred for 12 h, and then left to stand for 12 h to obtain a gel-like precursor.

[0131] Step 3: the gel-like precursor is subjected to hydrothermal treatment at a temperature of 160 ℃ for 18 h to obtain an intermediate electrode material, which is washed with water and then subjected to high-temperature calcination and carbonization treatment in a tube furnace under an argon atmosphere at a temperature of 550 ℃ for 3 h to obtain a titanium dioxide-based electrode material.

[0132] As shown in Figure 7 and Figure 8 , the titanium dioxide-based electrode material prepared in the comparative example is further prepared into a titanium dioxide-based electrode sheet, which can obtain a specific capacity of 176 mAh / g at a current density of 0.05 A / g, can obtain a specific capacity of 151 mAh / g at a current density of 0.1 A / g, can obtain a specific capacity of 132 mAh / g at a current density of 0.2 A / g, can obtain a specific capacity of 101 mAh / g at a current density of 0.5 A / g, can obtain a specific capacity of 77 mAh / g at a current density of 1 A / g, can obtain a specific capacity of 46 mAh / g at a current density of 2 A / g, and can only obtain a specific capacity of 17 mAh / g at a current density of 5 A / g, and has a capacity retention rate of 90% after 500 cycles at a current density of 1 A / g.

[0133] Comparative Example 1 is compared with Example 1, and Comparative Example 1 has poor performance, which is due to the fact that no expanding agent is added in the present comparative example, and the non-expanded layered titanium acid H 1.07 Ti 1.73 The carbon source molecules are not inserted into the interlayer due to the gap between the TiO4, and the periodic layered structure is not formed, and therefore, the specific capacity of the titanium dioxide-based electrode material prepared is low.

[0134] Comparative Example 2

[0135] The present comparative example provides a preparation method of a titanium dioxide-based electrode material, which is different from Example 1 in step four.

[0136] Specifically, step four of the present comparative example is as follows:

[0137] The gel precursor is subjected to hydrothermal treatment at a temperature of 140°C for 18h to obtain an intermediate electrode material, and the intermediate electrode material is washed with water and then subjected to high-temperature calcination and carbonization treatment in a tube furnace under an argon atmosphere at a temperature of 550°C for 3h to obtain a titanium dioxide-based electrode material.

[0138] It is found through rate performance test, constant-current charge and discharge capacity test and long cycle stability test that the titanium dioxide-based electrode sheet further prepared from the titanium dioxide-based electrode material prepared in the present comparative example can obtain a specific capacity of 120mAh / g at a current density of 0.1A / g, and can only obtain a specific capacity of 24mAh / g at a current density of 5A / g, and the capacity retention rate is 90% after 500 cycles at a current density of 1A / g.

[0139] Comparative Example 2 is compared with Example 1, and Comparative Example 2 has poor performance, which is due to the fact that a large number of carbon source molecules are not reacted and exist independently in the interlayer without polymerization due to the fact that the hydrothermal temperature of the gel precursor in the present comparative example is too low, and therefore, the specific capacity of the titanium dioxide-based electrode material prepared is low.

[0140] Comparative Example 3

[0141] The present comparative example provides a preparation method of a titanium dioxide-based electrode material, which is different from Example 1 in step four.

[0142] Specifically, step four of the present comparative example is as follows:

[0143] The gel precursor is subjected to hydrothermal treatment at a temperature of 160°C for 18h to obtain an intermediate electrode material, and the intermediate electrode material is washed with water and then subjected to high-temperature calcination and carbonization treatment in a tube furnace under an argon atmosphere at a temperature of 750°C for 3h to obtain a titanium dioxide-based electrode material.

[0144] The titanium dioxide-based electrode material prepared from the comparative example 1 is further prepared into a titanium dioxide-based electrode sheet, which can obtain a specific capacity of 110 mAh / g at a current density of 0.1 A / g, and can only obtain a specific capacity of 15 mAh / g at a current density of 5 A / g, and the capacity retention rate is 90% after 500 cycles at a current density of 1 A / g.

[0145] The comparative example 3 is compared with the example 1, and the comparative example 3 has poor performance, which is due to the fact that the carbonization temperature in the calcination and carbonization process of the comparative example is too high, which can further convert the anatase TiO2 to the rutile TiO2 and can cause the structure of the carbon material to be degraded or sintered, and thus the specific capacity of the prepared titanium dioxide-based electrode material is low.

[0146] Comparative example 4

[0147] The comparative example 1 provides a preparation method of a titanium dioxide-based electrode material, which is different from the example 1 in step three.

[0148] Specifically, step three of the comparative example is as follows:

[0149] 100 mL of a glucose solution with a concentration of 0.2 M is added to 0.1 g of the expanded layered titanate, and stirred for 0.2 h, and then left to stand for 12 h to obtain a colloidal precursor.

[0150] The titanium dioxide-based electrode material prepared from the comparative example 1 is further prepared into a titanium dioxide-based electrode sheet, which can obtain a specific capacity of 110 mAh / g at a current density of 0.1 A / g, and can only obtain a specific capacity of 15 mAh / g at a current density of 5 A / g, and the capacity retention rate is 90% after 500 cycles at a current density of 1 A / g.

[0151] The comparative example 4 is compared with the example 1, and the comparative example 4 has poor performance, which is due to the fact that the carbon layer insertion time in the comparative example is insufficient, and thus the carbon layer is less, and thus the specific capacity of the prepared titanium dioxide-based electrode material is low.

[0152] Comparative example 5

[0153] The comparative example 1 provides a preparation method of a titanium dioxide-based electrode material, which is different from the example 1 in step one.

[0154] Specifically, step one of the comparative example is as follows:

[0155] 5 g of the layered alkali titanate K 0.8 Li 0.27 Ti 1.73O4 powder is obtained by adding 500 mL of a hydrochloric acid solution with a concentration of 2 M to O4, and then performing filtration and drying treatment to obtain layered titanic acid H 1.07 Ti 1.73 O4 powder.

[0156] The titanium dioxide-based electrode material prepared by the present comparative example is further prepared into a titanium dioxide-based electrode sheet, which can obtain a specific capacity of 145 mAh / g at a current density of 0.1 A / g, and can only obtain a specific capacity of 12 mAh / g at a current density of 5 A / g, and the capacity retention rate is 90% after 500 cycles at a current density of 1 A / g.

[0157] Comparative Example 5 is compared with Example 1, and Comparative Example 5 has poor performance, which is due to the fact that the concentration of the hydrochloric acid solution is too high during acidification in the present comparative example, which may cause a series of problems such as crystal structure damage, impurity introduction, interlayer spacing change, and too fast reaction rate. Therefore, the specific capacity of the prepared titanium dioxide-based electrode material is low.

[0158] Comparative Example 6

[0159] The present comparative example provides a preparation method of a titanium dioxide-based electrode material, which comprises the following steps:

[0160] Step 1: 5 g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 powder is obtained by adding 500 mL of a hydrochloric acid solution with a concentration of 0.5 M to O4, and then performing filtration and drying treatment to obtain layered titanic acid H 1.07 Ti 1.73 O4 powder.

[0161] Step 2: The layered titanic acid H 1.07 Ti 1.73 O4 powder is directly high-temperature carbonized at a temperature of 550°C in a muffle furnace for 3 h to obtain a titanium dioxide electrode material without carbon coating or carbon intercalation.

[0162] As Figure 7 and Figure 8As shown, through the rate performance test, constant current charge and discharge capacity test and long cycle stability test, it is found that the titanium dioxide-based electrode material prepared by the present comparative example can obtain a specific capacity of 52 mAh / g at a current density of 0.05 A / g, a specific capacity of 47 mAh / g at a current density of 0.1 A / g, a specific capacity of 42 mAh / g at a current density of 0.2 A / g, a specific capacity of 34 mAh / g at a current density of 0.5 A / g, a specific capacity of 24 mAh / g at a current density of 1 A / g, a specific capacity of 11 mAh / g at a current density of 2 A / g, and a specific capacity of only 5 mAh / g at a current density of 5 A / g, and the capacity retention rate is 90% after 500 cycles at a current density of 1 A / g.

[0163] Comparative Example 6 is compared with Example 1, and the performance of Comparative Example 6 is poor, which is due to the fact that the present comparative example does not expand and does not perform carbon intercalation, so that the specific capacity of the prepared titanium dioxide-based electrode material is low.

[0164] The comparison results of Example 1 and Comparative Examples 1-6 show that the layered titanium dioxide-based electrode sheet (TiO2 / C electrode sheet) prepared in the present example has excellent electronic conductivity and ionic conductivity, and can significantly improve the rate performance of the anatase TiO2 electrode material. The electrode materials prepared in Comparative Examples 1-6 have poor conductivity and obvious decline in electrochemical performance due to the reasons that no expanding agent is added, the hydrothermal temperature of the colloidal precursor is too low, the carbonization temperature is too high, the carbon layer insertion time is insufficient, the acid solution concentration is too high during acidification, and no expansion and no carbon intercalation are performed.

[0165] In summary, the present application discloses a preparation method of a layered titanium dioxide-based electrode material, which comprises the following steps: 0.8 Li 0.27 Ti 1.73 O4 acidification treatment and then drying treatment by suction filtration to obtain layered titanium acid H 1.07 Ti 1.73The O4 powder is added with an expanding agent to obtain an expanded layered titanate, then a carbon precursor solution is added and stirred, and then the gelatinous precursor is obtained by standing, the gelatinous precursor is subjected to hydrothermal treatment to obtain an intermediate electrode material; the intermediate electrode material is washed with water and subjected to high-temperature calcination and carbonization treatment in an argon atmosphere tube furnace to obtain a layered titanium dioxide-based electrode material. The layered titanium dioxide-based electrode material solves the problems of poor conductivity of the anatase TiO2 electrode material and limited diffusion path of sodium ions, the carbon existing between the TiO2 layers establishes a conductive channel for ion migration, and the electronic conductivity and sodium ion conductivity of the TiO2 electrode material are improved, so that the electronic conductivity of the electrode material is increased, the capacity is fully exerted, and the rate performance is significantly improved, and a high actual capacity can still be maintained at a high current (high rate). The layered titanium dioxide-based electrode material has a wide application prospect in the field of sodium battery negative electrode materials.

[0166] The above is only used to illustrate the technical idea of the present application, and cannot be used to limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A method for preparing a layered titanium dioxide-based electrode material, characterized in that: The following steps are involved: Layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 is acidified and filtered and dried in sequence until layered titanate H 1.07 Ti 1.73 O4 powder, followed by layered titanate H 1.07 Ti 1.73 O4 powder is mixed with an expander and expanded to obtain expanded layered titanic acid. A carbon precursor solution is then added to the expanded layered titanic acid and stirred. During the stirring process, carbon is inserted between adjacent layers of the expanded layered titanic acid. The solution is then allowed to stand to obtain a colloidal precursor. The colloidal precursor is hydrothermally treated to obtain an intermediate electrode material. The intermediate electrode material is washed with water and then subjected to high-temperature calcination and carbonization to obtain a layered titanium dioxide-based electrode material. The acid solution used in the acidification treatment is a hydrochloric acid solution or a nitric acid solution; the concentration of the acid solution is 0.5M~1M; The expansion agent is any one of dimethylaminoethanol, methylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ethanolamine and hexadecyltrimethylammonium salt; The carbon precursor in the carbon precursor solution is any one of glucose, cellulose, polyethylene glycol and sodium citrate; The stirring time is 0.5h~24h; the temperature of the hydrothermal treatment is 160℃~180℃, and the temperature of the high-temperature calcination carbonization treatment is 550℃~650℃.

2. The method for preparing a layered titanium dioxide-based electrode material according to claim 1, wherein: The layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 The dosage ratio of O4 to acid solution is 1g~10g:100mL~2000mL.

3. The method for preparing a layered titanium dioxide-based electrode material according to claim 1, wherein: The concentration of the expansion agent is 0.02M~2M.

4. The method for preparing a layered titanium dioxide-based electrode material according to claim 1, wherein: The layered titanate H 1.07 Ti 1.73 The dosage ratio of O4 powder to expander is 0.1g~1g:50mL~500mL.

5. The method for preparing a layered titanium dioxide-based electrode material according to claim 1, wherein: The layered titanate H 1.07 Ti 1.73 The mixing time of O4 powder and expansion agent is 30min~90min.

6. The method for preparing a layered titanium dioxide-based electrode material according to claim 1, wherein: The concentration of the carbon precursor solution is 0.005M~0.5M.

7. The method for preparing a layered titanium dioxide-based electrode material according to claim 1, wherein: The ratio of the carbon precursor solution to the expanded layered titanic acid is 50 mL to 500 mL: 0.1 g to 1 g.

8. The method for preparing a layered titanium dioxide-based electrode material according to claim 1, wherein: The standing treatment time is 12h~24h; the hydrothermal treatment time is 8h~18h; the high-temperature calcination and carbonization treatment is carried out in an argon atmosphere, and the high-temperature calcination and carbonization treatment time is 3h~5h.

9. A layered titanium dioxide-based electrode material prepared by the method for preparing a layered titanium dioxide-based electrode material according to any one of claims 1 to 8, characterized in that: The layered titanium dioxide-based electrode material has a TiO2 / C periodic layered structure formed by alternating titanium dioxide layers and carbon layers.

10. Use of the layered titanium dioxide-based electrode material according to claim 9 as a negative electrode material in a sodium ion battery.

Images