Layered titanium dioxide-based electrode material and preparation method and application thereof

Abstract

The invention discloses a layered titanium dioxide-based electrode material as well as a preparation method and application thereof, and belongs to the technical field of a titanium-based negative electrode material of a sodium-ion battery. The preparation method comprises the following steps: sequentially carrying out acidification treatment and suction filtration and drying treatment on layered alkali metal titanate K0. 8Li0. 27Ti1. 73O4 to obtain layered titanic acid H1. 07Ti1. 73O4 powder, then mixing the layered titanic acid H1. 07Ti1. 73O4 powder with an expanding agent, carrying out expansion treatment to obtain expanded layered titanic acid, adding a carbon precursor solution into the expanded layered titanic acid, stirring, and then carrying out standing treatment to obtain a colloidal precursor; and carrying out hydrothermal treatment on the colloidal precursor to obtain an intermediate electrode material, washing the intermediate electrode material with water, and carrying out high-temperature calcination carbonization treatment to obtain the layered titanium dioxide-based electrode material. In the prepared material, the titanium dioxide layers and the carbon layers are alternately arranged, so that the carbon material is in full contact with TiO2, and the conductivity is improved to the maximum extent.

Description

Technical Field

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

[0002] Sodium-ion batteries, due to their low cost and high storage capacity, have shown great potential to replace lithium-ion batteries in the energy storage field. As a key component of sodium-ion batteries, the morphology and composition design of the anode material are crucial to meeting the high specific capacity and high-rate charge and discharge requirements of sodium batteries. This is the key to building high-performance sodium batteries and achieving their commercialization. Among alternative anode materials, titanium-based anode materials are considered ideal for sodium-ion battery anode materials due to their low sodiumization potential, low cost, non-toxicity, and good lattice stability.

[0003] Titanium-based anode materials are an important category of sodium-ion battery anode materials, primarily including titanium dioxide (TiO2) of various crystalline forms (such as anatase, rutile, and brookite) and titanates (such as lithium titanate and sodium titanate). Anatase TiO2, due to its unique crystal structure and excellent electrochemical properties, is considered to have great potential for achieving high specific capacity and high rate performance. However, its application is currently limited by two key factors. First, the large band gap of anatase TiO2 (approximately 3.2 eV) results in low electronic conductivity, which in turn affects the charge transfer efficiency of the electrode material. Second, when used as a sodium-ion battery anode material, the sodium ion insertion of micron-sized anatase TiO2 particles during the sodiation process is limited to a shallow reaction depth of approximately 5 nm on the surface. This depth is significantly smaller than the overall size of the micron-sized anatase TiO2 particles, resulting in a restricted sodium ion diffusion path and, in turn, restricting the full utilization of the anatase TiO2's sodium ion storage capacity. At present, a variety of improvement strategies have been proposed to address the shortcomings of layered anatase titanium dioxide, such as poor electronic conductivity and limited diffusion path of sodium ions. Common improvement strategies include the composite of titanium dioxide with highly conductive materials (such as carbon), titanium dioxide nanostructure design, and layered structure design.

[0004] The main direction of improvement of the above-mentioned composite strategy is to deeply composite layered anatase titanium dioxide with various two-dimensional materials, organic matter and inorganic matter through structural design. This composite method is widely used in the design of TiO2-type energy storage materials because of its significant improvement in conductivity, thereby achieving optimization of electrochemical performance. For example, titanium dioxide is composited with highly conductive materials (such as carbon) to improve the conductivity of layered anatase and limit the diffusion path of sodium ions. This method generally involves composite TiO2 with highly conductive materials such as graphene, carbon nanotubes and carbon dots to prepare TiO2 / C composite materials. The carbon is introduced into the TiO2 / C composite material by composited with pre-prepared carbon-based materials and 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 anatase TiO2 are not fully in contact, making it difficult to maximize the improvement of conductivity. In terms of titanium dioxide nanostructure design, research reports have pointed out that by nano-sizing the finished layered anatase through methods such as ball milling to reduce the size of anatase-type titanium dioxide particles, or by using techniques such as electrospinning to composite small-sized anatase with other conductive materials, its sodium ion diffusion capacity can be improved to a certain extent. However, the above-mentioned method of relying solely on size reduction has obvious disadvantages: on the one hand, the relevant preparation process is cumbersome and complicated, which increases production costs and operational difficulty; on the other hand, excessive reduction in particle size will lead to a sharp increase in specific surface area, thereby triggering excessive side reactions, which will significantly affect the stability of the electrode and is not conducive to its practical application and long-term performance. In terms of the design of layered negative electrodes with alternating two nanosheet layers to improve electronic conductivity and capacity, traditional design strategies can be divided into "bottom-up" and "top-down". Bottom-up composite strategies include layer-by-layer assembly, atomic layer deposition / molecular layer deposition, hydrothermal method and anti-solvent diffusion method; top-down composite strategies include electrochemical intercalation method and chemical intercalation method. However, traditional bottom-up structural design strategies inevitably lead to multilayer stacking and pillar agglomeration, while top-down strategies struggle to control the extent of molecular intercalation, easily leading to distortion of the host material's crystal structure during the intercalation process. The resulting structures from these two design strategies contain numerous defects, which, when used in batteries, can lead to significant electrolyte consumption and prevent optimal capacity.

[0005] In summary, in order to solve the intrinsic performance defects of anatase titanium dioxide material as the negative electrode material of sodium ion batteries, such as poor electronic conductivity and limited sodium ion diffusion path, traditional modification strategies have the following limitations: 1) Deficiencies of composite high-conductivity materials (such as carbon): insufficient interface contact and difficulty in maximizing conductivity; 2) Disadvantages of nanostructure design: complex preparation process and excessive specific surface area leading to side reactions; 3) Problems with layered structure design: bottom-up strategies are prone to multilayer stacking and pillar agglomeration, while top-down strategies are prone to lattice distortion of the main material. Summary of the Invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a layered titanium dioxide-based electrode material and its preparation method and application, so as to solve the technical problems of insufficient interface contact, difficulty in maximizing conductivity, complex preparation process and excessive specific surface area causing side reactions, bottom-up strategy prone to multi-layer stacking and pillar agglomeration, and top-down strategy prone to lattice distortion of the main material.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: 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 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.

[0008] In one embodiment, 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 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.

[0009] In one embodiment, the expander is any one of dimethylaminoethanol, methylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ethanolamine and hexadecyltrimethylammonium salt; and the concentration of the expander is 0.02M~2M.

[0010] In one embodiment, the layered titanate H 1.07 Ti 1.73 The dosage ratio of O4 powder to expander is 0.1g~1g:50mL~500mL.

[0011] In one embodiment, the layered titanate H 1.07 Ti 1.73 The mixing time of O4 powder and expansion agent is 30min~90min.

[0012] In one 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.

[0013] In one embodiment, 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.

[0014] In one embodiment, the stirring time is 0.5h~24h; the standing treatment time is 12h~24h; the temperature of the hydrothermal treatment is 160℃~180℃, and the hydrothermal treatment time is 8h~18h; the high-temperature calcination and carbonization treatment is carried out in an argon atmosphere, the temperature of the high-temperature calcination and carbonization treatment is 550℃~650℃, and the high-temperature calcination and carbonization treatment time is 3h~5h.

[0015] The second aspect of the present invention provides a layered titanium dioxide-based electrode material prepared by the above-mentioned method for preparing a layered titanium dioxide-based electrode material. The layered titanium dioxide-based electrode material has a TiO2 / C periodic layered structure formed by alternating titanium dioxide layers and carbon layers.

[0016] The third aspect of the present invention provides the use of the above-mentioned layered titanium dioxide-based electrode material as a negative electrode material in a sodium ion battery.

[0017] Compared with the prior art, the present invention has the following beneficial effects: On the one hand, the present invention provides a method for preparing a layered titanium dioxide-based electrode material, wherein a carbon source is inserted into the expanded layered titanium dioxide H by a method of first expansion and then intercalation. 1.07 Ti 1.73O4 in the gaps between adjacent layers, and then subjected to high temperature calcination and carbonization treatment, a TiO2 / C electrode material in which titanium dioxide layers and carbon layers are arranged alternately in a periodic structure is obtained. Specifically, the preparation method firstly treats the layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 O4 was acidified to obtain layered titanate H 1.07 Ti 1.73 O4, and then filtered and dried to remove the residual acid and water to obtain layered titanate H 1.07 Ti 1.73 O4 powder. Subsequently, by 1.07 Ti 1.73 The introduction of an expansion agent into the O4 powder weakens the interlayer electrostatic interaction and van der Waals force, forming an open interlayer channel that can accommodate carbon source molecules to obtain expanded layered titanic acid. Then, by adding a carbon precursor solution and stirring the intercalation method, the carbon precursor molecules are uniformly adsorbed on the expanded layered titanic acid H in the form of a monolayer or oligomer. 1.07 Ti 1.73 O4 adjacent layers to obtain a colloidal precursor. Finally, the obtained colloidal precursor is converted into a nano-scale amorphous carbon interlayer after hydrothermal treatment and high-temperature calcination and carbonization treatment, and finally a layered titanium dioxide-based electrode material is formed. The presence of carbon in the layered titanium dioxide-based electrode material with a periodic TiO2 / C structure obtained by the above-mentioned four steps of layered titanic acid expansion-carbon source intercalation-hydrothermal polymerization-high-temperature calcination and carbonization can maximize the electronic conductivity, thereby improving the electronic conductivity of anatase-type titanium dioxide-based electrode materials. By first expanding the layered titanic acid, the expansion process is used to open the interlayer gap, thereby avoiding the problem of pore blockage caused by the stacking and agglomeration of multi-layer nanosheets in the traditional bottom-up method. A mild intercalation method is used to introduce the carbon source to avoid the damage to the main lattice by strong external force or chemical etching, ensure the integrity of the titanium dioxide layered structure, and avoid the lattice distortion problem caused by the top-down method. The carbon source precursor is uniformly inserted into the interlayer gap after expansion, and a carbon layer that fits tightly with the titanium dioxide layer is formed after high-temperature calcination and carbonization, thereby optimizing the interface contact of the composite carbon, solving the problem of insufficient interface contact in traditional carbon composites, and improving the efficiency of electronic conduction. In addition, the layered structure design avoids excessive dispersion of nanoparticles, controls the specific surface area within a reasonable range, reduces the ineffective contact between the electrolyte and the active material, inhibits side reactions, and balances the specific surface area and side reactions of the nanostructure. Through the expansion-intercalation process, the sodium ion diffusion path is shortened, the material capacity potential is brought into play, and the rate performance is improved. In summary, this preparation method effectively solves the problems of poor electronic conductivity and limited sodium ion diffusion path when existing layered anatase-type titanium dioxide-based materials are used as negative electrode materials for sodium ion batteries, significantly improves the electronic conductivity of layered titanium dioxide-based electrode materials, and thus improves electronic conductivity.

[0018] 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.

[0019] 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

[0020] Figure 1 Schematic diagram of the structure of the layered titanium dioxide-based electrode material prepared in Example 1 of the present invention; Figure 2 The layered titanate H prepared in Example 1 of the present invention 1.07 Ti 1.73 XRD pattern of O4 powder; Figure 3 The layered titanate H prepared in Example 1 of the present invention 1.07 Ti 1.73 SEM image of O4 powder; Figure 4 This is an optical microscope image of the expanded layered titanic acid prepared in Example 1 of the present invention; Figure 5 This is a SEM image of the layered titanium dioxide-based electrode material prepared in Example 1 of the present invention; Figure 6 This is an element mapping diagram of the layered titanium dioxide-based electrode material prepared in Example 1 of the present invention; Figure 7 These are rate performance test graphs of the layered titanium dioxide-based electrode material prepared in Example 1 of the present invention, and the titanium dioxide-based electrode materials prepared in Comparative Examples 1 and 6; Figure 8 These are constant current charge-discharge capacity test and long cycle stability test diagrams of the layered titanium dioxide-based electrode material prepared in Example 1 of the present invention, and the titanium dioxide-based electrode materials prepared in Comparative Examples 1 and 6. DETAILED DESCRIPTION

[0021] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0022] All features, such as values, amounts, contents, and concentrations, described herein as numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0023] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0024] The present invention provides a layered titanium dioxide-based electrode material, a preparation method and an application thereof.

[0025] On the one hand, a method for preparing a layered titanium dioxide-based electrode material is provided, comprising the following steps: 0.8 Li 0.27 Ti 1.73 O4 is acidified and filtered and dried in sequence until layered titanate H 1.07 Ti 1.73O4 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.

[0026] More specifically, the method for preparing the layered titanium dioxide-based electrode material comprises the following steps: 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.

[0027] 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.

[0028] 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.

[0029] Preferably, the acid solution used in the acidification treatment is a hydrochloric acid solution or a nitric acid solution.

[0030] Preferably, the expander is any one of dimethylaminoethanol, methylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ethanolamine and cetyltrimethylammonium salt.

[0031] Preferably, the carbon precursor in the carbon precursor solution is any one of glucose, cellulose, polyethylene glycol and sodium citrate.

[0032] In the above preparation method, the solvents in the acid solution, the expansion agent and the carbon precursor solution are all pure water.

[0033] 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.

[0034] 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.

[0035] 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: 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.

[0036] 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.

[0037] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0038] The following examples use conventional instruments and equipment in the art. Experimental methods in the following examples where specific conditions are not specified are generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, are conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" represents percentage by weight, "part" represents parts by weight, and "ratio" represents weight ratio.

[0039] The assembly process of a sodium ion battery using a layered titanium dioxide-based electrode sheet as the negative electrode is as follows: The battery device assembled in the embodiment is a CR2032 button-type half-cell, wherein the positive and negative electrode shells are 2032 battery shells, the separator is a 16mm glass fiber separator, the electrolyte is 1.0M NaPF6inEC:DMC=1:1Vol% with 5.0% FEC, and the sodium sheet is a pre-cut 14mm sodium sheet.

[0040] The assembly sequence is reverse assembly: place the layered titanium dioxide-based electrode sheet in the center of the negative electrode casing, add 75μL of electrolyte, attach a glass fiber separator, and then add another 75μL of electrolyte. Then, place the aluminum foil of the sodium sheet facing up in the center of the separator, place the gasket and spring, and finally secure the positive electrode casing. Use insulated tweezers to pick up the entire battery and place it in the mold of the button battery sealing machine for sealing. This completes the assembly of a complete half-cell.

[0041] 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 were prepared using exactly the same processing flow when preparing the corresponding electrode sheets, and all were dried at a temperature of 80°C. The above-mentioned electrode sheets were used as negative electrode materials, and sodium-ion batteries were prepared based on exactly the same assembly process, and electrochemical performance tests were uniformly performed. Specific electrochemical performance test items include: rate performance test, constant current charge and discharge capacity test, and long cycle stability test.

[0042] Example 1 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: 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.

[0043] Step 2: 0.1g layered titanate H 1.07 Ti1.73 O4 powder was added to 100 mL of 0.2 M dimethylaminoethanol solution and mixed for 60 min to obtain expanded layered titanic acid.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 1.73 As shown in the optical microscope image of O4, it is obvious that layered titanate H 1.07 Ti 1.73 O4 crystals expand into long strips. Figure 5 As shown in the SEM image of the layered titanium dioxide-based electrode material prepared in this embodiment, the titanium dioxide layers and carbon layers in the material are alternately stacked. Figure 6As shown in the element mapping diagram of the layered titanium dioxide-based electrode material (TiO2 / C electrode material) prepared in this example, the Ti, C, and O elements in the material are evenly distributed, which further illustrates that the titanium dioxide layers and the carbon layers are alternately stacked.

[0048] like Figure 7 and Figure 8 As shown, after rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by the layered titanium dioxide-based electrode material prepared in this embodiment can obtain a specific capacity of 275mAh / g at a current density of 0.05A / g, a specific capacity of 252mAh / g at a current density of 0.1A / g, a specific capacity of 239mAh / g at a current density of 0.2A / g, a specific capacity of 211mAh / g at a current density of 0.5A / g, a specific capacity of 191mAh / g at a current density of 1A / g, a specific capacity of 154mAh / g at a current density of 2A / g, and a specific capacity of 126mAh / g at a current density of 5A / g. The capacity retention rate is 90% after 500 cycles at a current density of 1A / g.

[0049] Example 2 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: Step 1: add 1g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 100 mL of 0.5 M nitric 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.

[0050] Step 2: 0.1g layered titanate H 1.07 Ti 1.73 O4 powder was added to 50 mL of 0.02 M methylamine solution and mixed for 60 min to obtain expanded layered titanic acid.

[0051] Step 3: Immediately add 50 mL of 0.005 M cellulose 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.

[0052] Step 4: The colloidal precursor is hydrothermally treated at 160°C for 8 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 5 hours in an argon atmosphere tubular furnace to obtain a layered titanium dioxide-based electrode material.

[0053] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0054] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by using the layered titanium dioxide-based electrode material prepared in this 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. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0055] Example 3 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: Step 1: add 10g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 2000 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.

[0056] Step 2: 1g layered titanate H 1.07 Ti 1.73 O4 powder was added to 500 mL of 2M tetramethylammonium hydroxide solution and mixed for 50 min to obtain expanded layered titanic acid.

[0057] Step 3: Immediately add 500 mL of 0.5 M polyethylene glycol solution to 1 g of expanded layered titanic acid, stir for 12 h, and then let it stand for 12 h to obtain a colloidal precursor.

[0058] Step 4: The colloidal precursor is subjected to a hydrothermal treatment at a temperature of 180°C for 8 hours 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 650°C for 5 hours in an argon atmosphere tubular furnace to obtain a layered titanium dioxide-based electrode material.

[0059] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0060] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by using the layered titanium dioxide-based electrode material prepared in this embodiment can obtain a specific capacity of 174 mAh / g at a current density of 0.1 A / g, and a specific capacity of 56 mAh / g at a current density of 5 A / g. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0061] Example 4 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: Step 1: add 1g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 2000 mL of 1 M nitric 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.

[0062] Step 2: 0.1g layered titanate H 1.07 Ti 1.73 O4 powder was added to 500 mL of 0.02 M ethanolamine solution and mixed for 40 min to obtain expanded layered titanic acid.

[0063] Step 3: Immediately add 500 mL of 0.005 M sodium citrate solution to 0.1 g of expanded layered titanic acid, stir for 0.5 h, and then let it stand for 24 h to obtain a colloidal precursor.

[0064] Step 4: The colloidal precursor is subjected to a hydrothermal treatment at a temperature of 180°C for 18 hours 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 650°C for 3 hours in an argon atmosphere tubular furnace to obtain a layered titanium dioxide-based electrode material.

[0065] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0066] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by using the layered titanium dioxide-based electrode material prepared in this embodiment 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. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0067] Example 5 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: Step 1: add 10g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 100 mL of 1 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.

[0068] Step 2: 1g layered titanate H 1.07 Ti 1.73 O4 powder was added to 50 mL of 2 M hexadecyltrimethylammonium salt solution and mixed for 30 min to obtain expanded layered titanic acid.

[0069] Step 3: Immediately add 50 mL of 0.5 M glucose solution to 1 g of expanded layered titanic acid and stir for 24 h, then let it stand for 12 h to obtain a colloidal precursor.

[0070] Step 4 is the same as step 4 of Example 1, and a layered titanium dioxide-based electrode material is obtained.

[0071] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0072] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by using the layered titanium dioxide-based electrode material prepared in this embodiment 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. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0073] Example 6 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: Step 1: add 1g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 100 mL of 0.5 M nitric 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.

[0074] Step 2: 1g layered titanate H 1.07 Ti 1.73O4 powder was added to 500 mL of a 0.02 M dimethylaminoethanol solution and mixed for 70 min to obtain expanded layered titanic acid.

[0075] Step 3: Immediately add 50 mL of 0.5 M cellulose solution to 1 g of expanded layered titanic acid and stir for 12 h, then let it stand for 12 h to obtain a colloidal precursor.

[0076] Step 4 is the same as step 4 of Example 1, and a layered titanium dioxide-based electrode material is obtained.

[0077] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0078] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by using the layered titanium dioxide-based electrode material prepared in this 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. After 500 cycles at a current density of 1A / g, the capacity retention rate is 90%.

[0079] Example 7 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: Step 1: add 10g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 2000 mL of 1 M nitric 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.

[0080] Step 2: 0.1g layered titanate H 1.07 Ti 1.73 O4 powder was added to 50 mL of 2 M methylamine solution and mixed for 80 min to obtain expanded layered titanic acid.

[0081] Step 3: Immediately add 500 mL of 0.005 M polyethylene glycol solution to 0.1 g of expanded layered titanic acid, stir for 12 h, and then let it stand for 12 h to obtain a colloidal precursor.

[0082] Step 4 is the same as step 4 of Example 1, and a layered titanium dioxide-based electrode material is obtained.

[0083] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0084] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by using the layered titanium dioxide-based electrode material prepared in this embodiment 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. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0085] Example 8 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: Step 1: add 10g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 2000 mL of 1M 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.

[0086] Step 2: 0.1g layered titanate H 1.07 Ti 1.73 O4 powder was added to 500 mL of 0.02 M tetramethylammonium hydroxide solution and mixed for 60 min to obtain expanded layered titanic acid.

[0087] Step 3: Immediately add 500 mL of 0.005 M sodium citrate solution to 0.1 g of expanded layered titanic acid, stir for 12 h, and then let it stand for 12 h to obtain a colloidal precursor.

[0088] 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 650°C for 3 hours in an argon atmosphere tubular furnace to obtain a layered titanium dioxide-based electrode material.

[0089] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0090] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by using the layered titanium dioxide-based electrode material prepared in this embodiment can obtain a specific capacity of 131 mAh / g at a current density of 0.1 A / g, and a specific capacity of 40 mAh / g at a current density of 5 A / g. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0091] Example 9 On the one hand, this embodiment provides a method for preparing a layered titanium dioxide-based electrode material, comprising the following steps: Step 1: add 1g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 100 mL of 0.5 M nitric 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.

[0092] Step 2: 1g layered titanate H 1.07 Ti 1.73 O4 powder was added to 500 mL of 2 M tetraethylammonium hydroxide solution and mixed for 90 min to obtain expanded layered titanic acid.

[0093] Step 3: Immediately add 50 mL of 0.5 M sodium citrate solution to 1 g of expanded layered titanic acid, stir for 12 h, and then let it stand for 12 h to obtain a colloidal precursor.

[0094] Step 4: The colloidal precursor is hydrothermally treated at 180°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.

[0095] On the other hand, this embodiment also provides a layered titanium dioxide-based electrode material prepared by the above preparation method.

[0096] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the layered titanium dioxide-based electrode sheet further prepared by using the layered titanium dioxide-based electrode material prepared in this embodiment can obtain a specific capacity of 154 mAh / g at a current density of 0.1 A / g, and a specific capacity of 32 mAh / g at a current density of 5 A / g. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0097] Comparative Example 1 This comparative example provides a method for preparing a titanium dioxide-based electrode material, comprising the following steps: 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.

[0098] Step 2: Add 100 mL of 0.2 M glucose solution to 0.1 g of layered titanate H 1.07 Ti 1.73 O4 powder was stirred for 12 h, and then allowed to stand for 12 h to obtain a colloidal precursor.

[0099] Step three: hydrothermally treat the colloidal precursor 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 titanium dioxide-based electrode material.

[0100] like Figure 7 and Figure 8 As shown, after rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the titanium dioxide-based electrode sheet further prepared by using the titanium dioxide-based electrode material prepared in this comparative example can obtain a specific capacity of 176 mAh / g at a current density of 0.05 A / g, a specific capacity of 151 mAh / g at a current density of 0.1 A / g, a specific capacity of 132 mAh / g at a current density of 0.2 A / g, a specific capacity of 101 mAh / g at a current density of 0.5 A / g, a specific capacity of 77 mAh / g at a current density of 1 A / g, a specific capacity of 46 mAh / g at a current density of 2 A / g, and only a specific capacity of 17 mAh / g at a current density of 5 A / g. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0101] Comparison of Example 1 with Example 1 shows that the performance of Comparative Example 1 is poor. This is because no expansion agent is added in this comparative example, and the layered titanate H is not expanded. 1.07 Ti 1.73 The carbon source molecules are not inserted into the interlayer due to the O4 gap, and a periodic layered structure is not formed. Therefore, the specific capacity of the titanium dioxide-based electrode material is low.

[0102] Comparative Example 2 On the one hand, this comparative example provides a method for preparing a titanium dioxide-based electrode material, which differs from Example 1 in step four.

[0103] The specific step 4 of this comparative example is as follows: The colloidal precursor was hydrothermally treated at 140°C for 18 hours to obtain an intermediate electrode material. After washing the intermediate electrode material with water, it was subjected to high-temperature calcination and carbonization treatment at 550°C for 3 hours in an argon atmosphere tubular furnace to obtain a titanium dioxide-based electrode material.

[0104] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the titanium dioxide-based electrode sheet further prepared by using the titanium dioxide-based electrode material prepared in this comparative example can obtain a specific capacity of 120 mAh / g at a current density of 0.1 A / g, and can only obtain a specific capacity of 24 mAh / g at a current density of 5 A / g. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0105] Comparative Example 2 is compared with Example 1. The performance of Comparative Example 2 is poor. This is because the hydrothermal temperature of the colloidal precursor in this comparative example is too low, resulting in a large number of unreacted carbon source molecules and independent existence of unpolymerized carbon polymers between layers. Therefore, the specific capacity of the obtained titanium dioxide-based electrode material is low.

[0106] Comparative Example 3 On the one hand, this comparative example provides a method for preparing a titanium dioxide-based electrode material, which differs from Example 1 in step four.

[0107] The specific step 4 of this comparative example is as follows: The colloidal precursor was hydrothermally treated at 160°C for 18 hours to obtain an intermediate electrode material. After washing the intermediate electrode material with water, it was subjected to high-temperature calcination and carbonization treatment at 750°C for 3 hours in an argon atmosphere tubular furnace to obtain a titanium dioxide-based electrode material.

[0108] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the titanium dioxide-based electrode sheet further prepared by using the titanium dioxide-based electrode material prepared in this comparative example 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. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0109] Comparing Comparative Example 3 with Example 1, the performance of Comparative Example 3 is poor. This is because the carbonization temperature in the calcination carbonization treatment of this comparative example is too high, which may cause the anatase-type TiO2 to further transform into rutile-type TiO2 and may cause structural degradation or sintering of the carbon material. Therefore, the specific capacity of the obtained titanium dioxide-based electrode material is low.

[0110] Comparative Example 4 On the one hand, this comparative example provides a method for preparing a titanium dioxide-based electrode material, which differs from Example 1 in step three.

[0111] The specific step three of this comparative example is as follows: 100 mL of 0.2 M glucose solution was added to 0.1 g of expanded layered titanic acid and stirred for 0.2 h, and then allowed to stand for 12 h to obtain a colloidal precursor.

[0112] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the titanium dioxide-based electrode sheet further prepared by using the titanium dioxide-based electrode material prepared in this comparative example 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. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0113] Comparative Example 4 is compared with Example 1. The performance of Comparative Example 4 is poor. This is because the carbon layer insertion time in this comparative example is insufficient, resulting in less carbon layer. Therefore, the specific capacity of the prepared titanium dioxide-based electrode material is low.

[0114] Comparative Example 5 On the one hand, this comparative example provides a method for preparing a titanium dioxide-based electrode material, which differs from Example 1 in step 1.

[0115] The specific step 1 of this comparative example is as follows: To 5g layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 500 mL of 2M 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.

[0116] Through rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the titanium dioxide-based electrode sheet further prepared by using the titanium dioxide-based electrode material prepared in this comparative example 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. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0117] Comparative Example 5, compared with Example 1, exhibits poor performance. This is due to the excessively high concentration of the hydrochloric acid solution used during acidification, which can lead to a series of problems, including crystal structure destruction, impurity introduction, changes in interlayer spacing, and excessively rapid reaction rates. Consequently, the resulting titanium dioxide-based electrode material exhibits a low specific capacity.

[0118] Comparative Example 6 This comparative example provides a method for preparing a titanium dioxide-based electrode material, comprising the following steps: Step 1: add 5g of layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73500 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.

[0119] Step 2: Layered titanate H was heated in a muffle furnace at 550 °C. 1.07 Ti 1.73 O4 powder was directly carbonized at high temperature for 3 h to obtain titanium dioxide electrode material without carbon coating or carbon intercalation.

[0120] like Figure 7 and Figure 8 As shown, after rate performance test, constant current charge and discharge capacity test and long cycle stability test, it was found that the titanium dioxide-based electrode sheet further prepared by using the titanium dioxide-based electrode material prepared in this 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 only a specific capacity of 5 mAh / g at a current density of 5 A / g. After 500 cycles at a current density of 1 A / g, the capacity retention rate is 90%.

[0121] Comparative Example 6 is compared with Example 1. The performance of Comparative Example 6 is poor. This is because no expansion and carbon intercalation are performed in this comparative example. Therefore, the specific capacity of the prepared carbon dioxide electrode material is low.

[0122] Comparison of Example 1 with Comparative Examples 1 through 6 demonstrates that the layered titanium dioxide-based electrode sheet (TiO2 / C electrode sheet) prepared in accordance with the present invention exhibits excellent electronic and ionic conductivity, significantly improving the rate performance of anatase TiO2 electrode materials. However, the electrode materials prepared in Comparative Examples 1 through 6 exhibit poor conductivity and significantly reduced electrochemical performance due to the lack of an expander, low hydrothermal temperature of the colloidal precursor, excessively high carbonization temperature, insufficient carbon layer insertion time, excessively high acid solution concentration during acidification, and the lack of expansion and carbon intercalation.

[0123] In summary, the present invention discloses a method for preparing a layered titanium dioxide-based electrode material, the preparation method comprising: preparing a layered alkali metal titanate K 0.8 Li 0.27 Ti 1.73 After O4 acidification, filtration and drying were performed to obtain layered titanate H 1.07 Ti1.73 O4 powder is then added, followed by an expansion agent to obtain expanded layered titanic acid. A carbon precursor solution is then added and stirred, followed by a quiescent state to obtain a colloidal precursor. The colloidal precursor is then hydrothermally treated to obtain an intermediate electrode material. The intermediate electrode material is then washed with water and subjected to high-temperature calcination and carbonization in an argon atmosphere tubular furnace to obtain a layered titanium dioxide-based electrode material. This invention addresses the problems of poor conductivity and limited sodium ion diffusion paths in anatase-type TiO2 electrode materials. The carbon present between the TiO2 layers establishes a conductive channel for ion migration, while simultaneously improving the electronic conductivity and sodium ion conductivity of the TiO2 electrode material. This increases the electronic conductivity of the electrode material, fully utilizes its capacity, and significantly improves its rate performance, maintaining a high actual capacity even at high currents (high rates). This layered titanium dioxide-based electrode material has broad application prospects in the field of negative electrode materials for sodium batteries.

[0124] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

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 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.

2. The method for preparing a layered titanium dioxide-based electrode material according to claim 1, wherein: 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 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 expander is any one of dimethylaminoethanol, methylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ethanolamine and hexadecyltrimethylammonium salt; and the concentration of the expander 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 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.

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 stirring time is 0.5h~24h; the static treatment time is 12h~24h; the temperature of the hydrothermal treatment is 160℃~180℃, and the hydrothermal treatment time is 8h~18h; the high-temperature calcination and carbonization treatment is carried out in an argon atmosphere, the temperature of the high-temperature calcination and carbonization treatment is 550℃~650℃, 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.

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