Modified molybdenum trioxide, method for preparing same, and use thereof

Abstract

The application provides a modified molybdenum trioxide and a preparation method and application thereof. The preparation method of the modified molybdenum trioxide comprises the following steps: providing a molybdenum trioxide precursor, which has a one-dimensional nanobelt morphology, and the length-diameter ratio of the one-dimensional nanobelt is greater than or equal to 20; applying pulse plasma in a reducing atmosphere, and activating the precursor at a first temperature of 25-150 DEG C; increasing the temperature of the activated precursor from the first temperature to a second temperature of 280-320 DEG C at a speed of 1-5 DEG C / min in a first atmosphere containing ammonia and nitrogen, and reacting for 30-90 min to prepare an intermediate; and cooling the intermediate by introducing a second atmosphere containing nitrogen and hydrogen at a flow rate of 200-800 sccm. The preparation method of the modified molybdenum trioxide provided by the application can maintain the one-dimensional nanobelt structure of the molybdenum trioxide precursor, and the prepared modified molybdenum trioxide also has an alpha-MoO3 orthorhombic crystal skeleton and moderate oxygen vacancies.

Description

Technical Field

[0001] This application relates to the field of functional materials technology, specifically to a modified molybdenum trioxide, its preparation method, and its applications. Background Technology

[0002] Molybdenum trioxide (α-MoO3) possesses a layered orthorhombic crystal structure with van der Waals interstices along the b-axis (corresponding to the {0k0} crystal plane family), making it prone to intercalation, defect manipulation, and anisotropic modification. One-dimensional MoO3 nanoribbons have attracted considerable attention in gas sensing, catalysis, and energy storage fields due to their high specific surface area, directional carrier transport channels, and excellent structural stability. However, the large band gap, low carrier concentration, and poor room-temperature conductivity of intrinsic MoO3 limit its application in electronic devices.

[0003] Traditional strategies for improving the conductivity of MoO3 have significant drawbacks. For example, high-temperature reduction methods (H2 / Ar or N2, >400℃) can introduce oxygen vacancies to improve conductivity, but the thermodynamic driving force is too strong and easily induces MoO3 oxidation. 6+ Xiang Mo 4+ Deep reduction generates MoO2 with a monoclinic distorted rutile structure or other reduced intermediate phases (such as magnel phases), disrupting the one-dimensional morphology. Metal doping (such as Sn, Co, or Cu) introduces heterogeneous metal atoms to adjust the energy band, but it easily forms second-phase segregation or disordered lattice distortion centers, increasing carrier scattering, and the uniformity and batch consistency of doping are difficult to control. Furthermore, because commercial bulk materials lack preferred orientation, precise control of specific crystal planes (such as the {0k0} plane) is impossible, thus limiting the control of MoO3 crystal planes. Summary of the Invention

[0004] In view of this, this application provides a modified molybdenum trioxide, its preparation method, and its application to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, in a first aspect, this application provides a method for preparing modified molybdenum trioxide, comprising the following steps: providing a molybdenum trioxide precursor having a one-dimensional nanoribbon morphology with an aspect ratio ≥20; applying pulsed plasma in a reducing atmosphere and activating the molybdenum trioxide precursor at a first temperature of 25°C to 150°C; heating the activated molybdenum trioxide precursor from the first temperature to a second temperature in the first atmosphere to carry out a reaction, wherein the first atmosphere includes ammonia and nitrogen, the heating rate is 1°C / min to 5°C / min, the second temperature is 280°C to 320°C, and the reaction time is 30 min to 90 min, thereby preparing an intermediate; introducing a second atmosphere to cool the intermediate, wherein the second atmosphere includes nitrogen and hydrogen, and the flow rate of the second atmosphere is 200 sccm to 800 sccm, thereby preparing modified molybdenum trioxide.

[0006] Based on the first aspect, in some embodiments, the flow rate of ammonia in the first atmosphere is 20 sccm to 50 sccm.

[0007] Based on the first aspect, in some embodiments, the volume ratio of ammonia to nitrogen in the first atmosphere is ≥4.

[0008] Based on the first aspect, in some embodiments, the molybdenum trioxide precursor also satisfies the following: in the X-ray diffraction pattern, the diffraction peak intensity is higher than that of I. (040) / I (110) ≥30.

[0009] Based on the first aspect, in some embodiments, the discharge frequency of the pulsed plasma is 1 kHz to 100 kHz, the pulse duty cycle is 5% to 50%, and the discharge power is 10 W to 500 W.

[0010] Based on the first aspect, in some embodiments, the pressure of the reducing atmosphere is 10 Pa to 10 Pa. 5 Pa.

[0011] Based on the first aspect, in some embodiments, the reducing atmosphere includes hydrogen and an inert gas, wherein the volume percentage of hydrogen is 1% to 20%.

[0012] Based on the first aspect, in some implementations, the activation time is 10 s to 60 s.

[0013] Based on the first aspect, in some embodiments, the volume ratio of nitrogen to hydrogen in the second atmosphere is ≥9.

[0014] Based on the first aspect, in some embodiments, before introducing the second atmosphere, the preparation method further includes: separating the intermediate from the first atmosphere.

[0015] Secondly, this application provides a modified molybdenum trioxide, which is prepared by the above-described preparation method; the modified molybdenum trioxide retains a one-dimensional nanoribbon morphology; the modified molybdenum trioxide includes defect-state MoO with a long-range ordered lattice framework and containing oxygen vacancies. 3-x , 0 < X ​​< 1.

[0016] Based on the second aspect, in some embodiments, the modified molybdenum trioxide satisfies the following condition: in the X-ray photoelectron spectroscopy, the valence state of molybdenum includes +6, +5 and / or +4.

[0017] Based on the second aspect, in some embodiments, the modified molybdenum trioxide satisfies the following: in the X-ray diffraction pattern, the 2θ angle value of the diffraction peak of the (040) crystal plane of the modified molybdenum trioxide is defined as A, the 2θ angle value of the diffraction peak of the (040) crystal plane of the molybdenum trioxide precursor is B, and 0.060≤AB≤0.145.

[0018] Based on the second aspect, in some embodiments, the modified molybdenum trioxide satisfies the following: in the X-ray diffraction pattern, the full width at half maximum (FWHM) of the diffraction peak of the (040) crystal plane of the modified molybdenum trioxide is defined as M, and the full WHM of the diffraction peak of the (040) crystal plane of the molybdenum trioxide precursor is defined as N, 1.240≤M / N≤1.545.

[0019] Based on the second aspect, in some embodiments, the modified molybdenum trioxide satisfies the following: in the X-ray diffraction pattern, the strongest peak integrated area of ​​the (040) crystal plane of the modified molybdenum trioxide is defined as K, the strongest peak integrated area of ​​the (040) crystal plane of the molybdenum trioxide precursor is defined as L, and 0.410≤K / L≤0.425.

[0020] Thirdly, this application provides the application of the above-mentioned modified molybdenum trioxide in the preparation of electrode active materials, wherein the electrode active materials have pseudocapacitive energy storage characteristics.

[0021] Compared to traditional technologies, the advantages of this application are as follows:

[0022] The method for preparing modified molybdenum trioxide provided in this application involves generating plasma in a reducing atmosphere to activate the molybdenum trioxide precursor at a first temperature. High-energy active particles in the plasma selectively etch oxygen atoms on the surface of nanoribbons to introduce oxygen vacancies. After plasma activation, the subsequent reaction can be completed in only 30 to 90 minutes under an ammonia atmosphere. Compared with the several hours required by traditional ammonia heat treatment, the isothermal reaction time is significantly shortened, while avoiding excessive reduction and morphology damage caused by prolonged high-temperature reaction. The activated molybdenum trioxide precursor is heated from a first temperature to a second temperature in a first atmosphere containing ammonia at a preset heating rate. This preset heating rate helps reduce the fracture of one-dimensional nanoribbons caused by excessively rapid accumulation of thermal stress, thereby helping to maintain the one-dimensional nanoribbon morphology of the molybdenum trioxide precursor. At the same time, it prevents energy waste and the risk of impurity phase formation caused by excessively slow heating. In addition, this second temperature window helps to reduce the excessive reduction of molybdenum trioxide to MoO2 or other impurity phases while introducing oxygen vacancies, thereby maintaining the α-MoO3 orthorhombic crystal system framework. After the reaction, a second atmosphere containing nitrogen at a preset flow rate is introduced for cooling. The rapid cooling effect generated by the nitrogen at this flow rate helps to prevent the oxygen vacancies generated at high temperature from annihilating during the slow cooling process, and further densifies the lattice by thermal contraction, thereby obtaining modified molybdenum trioxide with reduced interplanar spacing, defect locking, more complete morphology and less impurity phase formation. Attached Figure Description

[0023] Figure 1 This is an SEM image of modified molybdenum trioxide provided in Example 1 of this application.

[0024] Figure 2XPS spectra of modified molybdenum trioxide provided in Example 1 of this application.

[0025] Figure 3 The XRD patterns of modified molybdenum trioxide provided in Examples 1 and 3 of this application are shown.

[0026] Figure 4 The XRD patterns of modified molybdenum trioxide provided in Example 1 and Comparative Example 1 of this application.

[0027] Figure 5 The XRD patterns of modified molybdenum trioxide provided in Example 1 and Comparative Examples 2-3 of this application.

[0028] Figure 6 The XRD patterns of modified molybdenum trioxide provided in Example 1 and Comparative Examples 4-5 of this application.

[0029] Figure 7 The XRD patterns of modified molybdenum trioxide provided in Example 1 and Comparative Example 6 of this application.

[0030] Figure 8 The XRD patterns of modified molybdenum trioxide provided in Example 1 and Comparative Example 9 of this application. Detailed Implementation

[0031] To facilitate understanding of the technical solutions of this application, a more comprehensive description of the technical solutions of this application will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the technical solutions of this application. However, the technical solutions of this application can be implemented in many different forms and are not limited to the embodiments described herein. Rather, these embodiments are provided to enable a more thorough and comprehensive understanding of the disclosure of the technical solutions of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] One embodiment of this application provides a method for preparing modified molybdenum trioxide, comprising the following steps:

[0034] Step 1: Provide a molybdenum trioxide precursor with a one-dimensional nanoribbon morphology and an aspect ratio of ≥20.

[0035] In the above steps, the aspect ratio of the one-dimensional nanoribbons in the molybdenum trioxide precursor is controlled within a preset range. The molybdenum trioxide precursor has a high proportion of (0k0) crystal planes exposed, which is beneficial for the subsequent ammonia treatment to directionally regulate the crystal plane family and avoid the limitation of crystal plane regulation caused by bulk materials without preferred orientation.

[0036] In some embodiments, the molybdenum trioxide precursor also satisfies the following: in the X-ray diffraction pattern, the diffraction peak intensity is greater than that of I. (040) / I (110) ≥30. When the diffraction peak intensity ratio is controlled within the above range, the molybdenum trioxide precursor has a high proportion of {0k0} crystal plane exposure.

[0037] In some embodiments, the molybdenum trioxide precursor is prepared by a hydrothermal method. Understandably, the molybdenum trioxide precursor can be prepared by reacting metallic molybdenum powder or molybdenum trioxide with hydrogen peroxide to obtain peroxymolybdic acid, followed by dilution with water and hydrothermal reaction (e.g., hydrothermal at 160°C~180°C for >6 h).

[0038] Step 2: Apply pulsed plasma in a reducing atmosphere and activate the molybdenum trioxide precursor at a first temperature, which is 25℃~150℃. For example, the first temperature can be 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, or any value within the range of any two of the above values.

[0039] In the above steps, plasma is generated in a reducing atmosphere to activate the molybdenum trioxide precursor at a first temperature. High-energy active particles in the plasma selectively etch oxygen atoms onto the nanoribbon surface to introduce oxygen vacancies. After plasma activation, subsequent reactions can be completed in only 30-90 minutes under an ammonia atmosphere. Compared to the several hours required by traditional ammonia heat treatment, this significantly shortens the isothermal reaction time and avoids excessive reduction and morphological damage caused by prolonged high-temperature reactions. Understandably, taking a hydrogen and argon mixture as an example, the high-energy active particles mentioned above are H radicals and Ar radicals. + .

[0040] In some embodiments, the discharge frequency of the pulsed plasma is 1 kHz to 100 kHz, the pulse duty cycle is 5% to 50%, and the discharge power is 10 W to 500 W. For example, the discharge frequency of the pulsed plasma can be 1 kHz, 5 kHz, 10 kHz, 20 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, 70 kHz, 80 kHz, 90 kHz, 100 kHz, or any value within the range of any two of the above values; the pulse duty cycle can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any value within the range of any two of the above values; and the discharge power can be 10 W, 50 W, 100 W, 150 W, 200 W, 250 W, 300 W, 350 W, 400 W, 450 W, 500 W, or any value within the range of any two of the above values. Controlling the application conditions of the aforementioned pulsed plasma helps to generate sufficient plasma in a reducing atmosphere, thereby promoting the introduction of oxygen vacancies in the nanoribbons.

[0041] In some embodiments, the pressure of the reducing atmosphere is 10 Pa to 10 Pa. 5 Pa. For example, the pressure of a reducing atmosphere can be 10 Pa, 10 Pa. 2 Pa, 10 3 Pa, 10 4 Pa, 10 5 Pa or any value within the range of any two of the above values. Controlling the pressure of the reducing atmosphere within the above range helps to activate the molybdenum trioxide precursor in a sufficient gas atmosphere.

[0042] In some embodiments, the reducing atmosphere comprises hydrogen and an inert gas, wherein the volume percentage of hydrogen is 1% to 20%. For example, the volume percentage of hydrogen in the reducing atmosphere can be 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, or any value within the range of any two of the above values. Controlling the composition and proportion of the reducing atmosphere helps to regulate the composition of high-energy active particles in the plasma, thereby promoting the introduction of oxygen vacancies into the nanoribbons.

[0043] In some embodiments, the activation time is 10 s to 60 s. For example, the activation time can be 10 s, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s, 55 s, 60 s, or any value within the range of any two of the above values. Controlling the activation time within the above range helps to fully introduce and immobilize oxygen vacancies in the molybdenum trioxide precursor nanoribbons during the activation process.

[0044] Step 3: The activated molybdenum trioxide precursor is heated from a first temperature to a second temperature under a first atmosphere, which includes ammonia and nitrogen, to carry out the reaction. The heating rate is 1℃ / min to 5℃ / min, the second temperature is 280℃ to 320℃, and the reaction time is 30 min to 90 min to prepare the intermediate. For example, the heating rate can be 1℃ / min, 1.4℃ / min, 1.8℃ / min, 2.2℃ / min, 2.6℃ / min, 3℃ / min, 3.4℃ / min, 3.8℃ / min, 4.2℃ / min, 4.6℃ / min, 5℃ / min, or any value within the range of any two of the above values; the second temperature can be 280℃, 284℃, 288℃, 292℃, 296℃, 300℃, 304℃, 308℃, 312℃, 316℃, 320℃, or any value within the range of any two of the above values; the reaction time can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, or any value within the range of any two of the above values.

[0045] In the above steps, heating the molybdenum trioxide precursor to a second temperature in a first atmosphere containing ammonia at a preset heating rate helps reduce the fracture of one-dimensional nanoribbons caused by excessively rapid thermal stress accumulation, thereby helping to maintain the one-dimensional nanoribbon morphology of the molybdenum trioxide precursor. Simultaneously, it prevents energy waste and the risk of impurity phase formation caused by excessively slow heating. Furthermore, this second temperature window helps to reduce the excessive reduction of molybdenum trioxide to MoO2 or other impurity phases while introducing oxygen vacancies, thus maintaining the α-MoO3 orthorhombic crystal framework. Controlling the reaction time within the above range helps to achieve moderate and uniform interplanar spacing shrinkage and oxygen vacancy introduction, reducing the risk of insufficient modification when the time is too short, and excessive lattice distortion or impurity phase formation when the time is too long.

[0046] Understandably, one-dimensional nanoribbons are brittle. When the temperature rises too quickly (>5℃ / min), internal thermal stress accumulates, causing the nanoribbons to break into fragments along the axial direction. When the temperature rises too slowly (<1℃ / min), ammonia is wasted and energy consumption increases.

[0047] Understandably, when the second temperature is too low (<280℃), the reaction kinetics are insufficient and the reaction may not occur, while when the second temperature is too high (>320℃), it will lead to excessive reduction and the formation of impurity phases.

[0048] Understandably, when the reaction time is insufficient (e.g., <30 min), the diffusion of the {0k0} characteristic crystal plane is insufficient; when the reaction time is too long (e.g., >90 min), the diffusion reaction continues to maintain the reaction after reaching the upper limit, which will cause the low-angle diffraction peaks of the {0k0} characteristic crystal plane to gradually increase and the high-angle diffraction peaks to gradually disappear after splitting, and the asymmetric contraction and expansion of the (110) crystal plane diffraction peak shifting to the right and the (021) crystal plane diffraction peak shifting to the left.

[0049] In some embodiments, the flow rate of ammonia in the first atmosphere is 20 sccm to 50 sccm. For example, the flow rate of ammonia in the first atmosphere can be 20 sccm, 23 sccm, 26 sccm, 29 sccm, 32 sccm, 35 sccm, 38 sccm, 41 sccm, 44 sccm, 47 sccm, 50 sccm, or any value within the range of any two of the above values. Controlling the flow rate of ammonia in the first atmosphere within the above range helps to maintain a stable reducing environment under a slightly positive pressure.

[0050] In some embodiments, the volume ratio of ammonia to nitrogen in the first atmosphere is ≥4. Understandably, in the first atmosphere, the volume percentage of nitrogen is between 0% and 20% and not zero, and the volume percentage of ammonia is between 80% and 100% and not 100%, thus ammonia and nitrogen have the aforementioned preset volume ratio. For example, in the first atmosphere, the volume percentage of nitrogen can be 0.01%, 0.1%, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, or any value within the range of any two of the above values; the volume percentage of ammonia can be 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, 98%, 99%, 99.9%, 99.99%, or any value within the range of any two of the above values. When the volume percentage of ammonia in the first atmosphere is controlled within the above range, higher purity ammonia helps to avoid interference from impurity gases (such as oxygen and water vapor) in the reduction reaction, and helps to further improve the singularity and controllability of defect introduction.

[0051] Step 4: Introduce a second atmosphere to cool the intermediate. The second atmosphere consists of nitrogen and hydrogen, and its flow rate is 200 sccm to 800 sccm to prepare modified molybdenum trioxide. For example, the flow rate of the second atmosphere can be 200 sccm, 250 sccm, 300 sccm, 350 sccm, 400 sccm, 450 sccm, 500 sccm, 550 sccm, 600 sccm, 650 sccm, 700 sccm, 750 sccm, 800 sccm, or any value within the range of any two of the above values.

[0052] In the above steps, a second atmosphere containing nitrogen gas at a preset flow rate is introduced after the reaction for cooling. The rapid cooling effect generated by the nitrogen gas at this flow rate helps to prevent the oxygen vacancies generated at high temperature from being annihilated during the slow cooling process, and further densifies the lattice by using thermal contraction, thereby obtaining modified molybdenum trioxide with reduced interplanar spacing, defect locking, more complete morphology and less impurity phase formation.

[0053] In some embodiments, the volume ratio of nitrogen to hydrogen in the second atmosphere is ≥9. It is understood that in the second atmosphere, the volume percentage of hydrogen is between 0% and 10% and not 0, and the volume percentage of nitrogen is between 90% and 100% and not 100%, thus achieving the aforementioned preset volume ratio. For example, in the second atmosphere, the volume percentage of hydrogen can be 0.01%, 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value within the range of any two of the above values; the volume percentage of nitrogen can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.9%, 99.99%, or any value within the range of any two of the above values. When the volume percentage of nitrogen in the second atmosphere is controlled within the above range, higher purity nitrogen helps to reduce the reaction between residual oxidizing gases and high-temperature products during rapid cooling, maintaining the oxygen vacancy concentration.

[0054] In some embodiments, before introducing the second atmosphere, the preparation method further includes separating the intermediate from the first atmosphere. These steps help prevent residual ammonia from continuing to react with the product during cooling, thereby helping to better maintain the defect structures and interplanar spacing formed during the reaction stage.

[0055] One embodiment of this application also provides a modified molybdenum trioxide, which is prepared by the above-described preparation method. The modified molybdenum trioxide retains a one-dimensional nanoribbon morphology and includes defect-state MoO₂ containing oxygen vacancies and a long-range ordered lattice framework. 3-x , 0 < X ​​< 1.

[0056] In this application, the modified molybdenum trioxide maintains the one-dimensional nanoribbon structure of the precursor, which is beneficial for the axial directional transport of charge carriers. At the same time, the orthorhombic crystalline framework of α-MoO3 means that the long-range ordered structure is not destroyed, avoiding the decrease in mechanical strength caused by complete amorphization. Meanwhile, the moderate oxygen vacancies (x < 1) help to improve electronic conductivity without generating impurity phases such as MoO2, thereby helping to achieve a balance between structural stability and intrinsic conductivity.

[0057] In some embodiments, the modified molybdenum trioxide satisfies the following conditions: in X-ray photoelectron spectroscopy, the valence states of molybdenum include +6, +5, and / or +4. The presence of these mixed valence states facilitates the formation of electronic transition channels, reduces the material resistivity, and also demonstrates the presence of oxygen vacancies.

[0058] In some embodiments, the modified molybdenum trioxide satisfies the following: in the X-ray diffraction pattern, the 2θ angle value of the diffraction peak of the (040) crystal plane of the modified molybdenum trioxide is defined as A, and the 2θ angle value of the diffraction peak of the (040) crystal plane of the molybdenum trioxide precursor is defined as B, 0.060≤AB≤0.145. For example, AB can be 0.060, 0.065, 0.070, 0.075, 0.080, 0.085, 0.090, 0.095, 0.100, 0.110, 0.120, 0.130, 0.140, 0.145, or any value within the range of any two of the above values. In modified molybdenum trioxide, the range of this angle shift towards higher angles indicates a controllable reduction in interplanar spacing, which is beneficial for enhancing interlayer van der Waals forces and improving structural rigidity.

[0059] In some embodiments, the modified molybdenum trioxide satisfies the following: in the X-ray diffraction pattern, the full width at half maximum (FWHM) of the diffraction peak on the (040) crystal plane of the modified molybdenum trioxide is defined as M, and the FWHM of the diffraction peak on the (040) crystal plane of the molybdenum trioxide precursor is defined as N, where 1.240 ≤ M / N ≤ 1.545. For example, M / N can be 1.240, 1.270, 1.300, 1.330, 1.360, 1.390, 1.420, 1.450, 1.480, 1.510, 1.540, 1.545, or any value within the range of any two of the above values. In the modified molybdenum trioxide, the increase in this FWHM indicates the introduction of abundant defects within the lattice without disrupting the orthorhombic α-MoO3 crystal framework, which helps to improve electrochemical activity without sacrificing structural integrity.

[0060] In some embodiments, the modified molybdenum trioxide satisfies the following: in the X-ray diffraction pattern, the integrated area of ​​the strongest peak on the (040) crystal plane of the modified molybdenum trioxide is defined as K, and the integrated area of ​​the strongest peak on the (040) crystal plane of the molybdenum trioxide precursor is defined as L, and 0.410 ≤ K / L ≤ 0.425. For example, K / L can be 0.410, 0.411, 0.412, 0.413, 0.414, 0.415, 0.417, 0.419, 0.421, 0.423, 0.425, or any value within the range of any two of the above values. In the modified molybdenum trioxide, the decrease in the integrated area of ​​the strongest peak reflects a moderate decrease in crystallinity.

[0061] One embodiment of this application also provides the application of the above-described modified molybdenum trioxide in the preparation of electrode active materials, wherein the electrode active materials have pseudocapacitive energy storage characteristics.

[0062] In this application, the modified molybdenum trioxide has a one-dimensional nanoribbon morphology, a long-range ordered lattice framework with defective state structures containing oxygen vacancies, mixed valence states, and a contracted {0k0} interplanar spacing. When used as an active material for lithium-ion battery electrodes, it helps to reduce resistivity, has pseudocapacitive energy storage characteristics, is beneficial for providing fast Faraday redox reaction sites, and achieves efficient ion / electron transport in the one-dimensional axial direction, thus making it suitable for high-power fast charging scenarios.

[0063] The present application will be described below through specific embodiments and comparative examples. Those skilled in the art should understand that the preparation methods described in this application are merely examples, and any other suitable preparation methods are within the scope of this application.

[0064] Example 1:

[0065] A modified molybdenum trioxide, the preparation method of which includes:

[0066] Step 1: Take 10 g of MoO3 prepared by hydrothermal method, which has a one-dimensional nanoribbon morphology (aspect ratio = 72), and spread it flat in a porcelain boat.

[0067] Step 2: In a mixture of hydrogen and argon (volume ratio 10:90), pulsed plasma is applied with a discharge frequency of 50 kHz, a pulse duty cycle of 25%, and a discharge power of 250 W to activate MoO3 at a first temperature of 100 °C.

[0068] Step 3: After three vacuum cycles and purging with NH3, a mixture of ammonia and nitrogen (first atmosphere) is introduced at a flow rate of 30 sccm, with a volume ratio of ammonia to nitrogen of 90:10. The temperature is increased from the first temperature to the second temperature of 300℃ at a rate of 2℃ / min. The reaction is carried out at the second temperature for 90 min, with the flow rate of NH3 maintained at 30 sccm throughout.

[0069] Step 4: At the moment the heat preservation ends, switch the gas path and introduce a mixture of nitrogen and hydrogen (second atmosphere) at a flow rate of 500 sccm, with a nitrogen to hydrogen volume ratio of 95:5. Allow it to cool naturally or with auxiliary air cooling to room temperature to obtain a powder that is approximately black or dark blue, thus obtaining modified molybdenum trioxide (MoO). 3-x , 0 < X ​​< 1.

[0070] Example 2:

[0071] The difference from Example 1 is that in the second step, the volume ratio of hydrogen to argon is 1:99, the discharge frequency of the pulsed plasma is 100 kHz, the pulse duty cycle is 5%, and the discharge power is 10 W; in the third step, the flow rate of the first atmosphere is 20 sccm, the volume ratio of ammonia to nitrogen in the first atmosphere is 99:1, the heating rate is 1℃ / min, the second temperature is 280℃, and the reaction time is 60 min; in the fourth step, the flow rate of the second atmosphere is 200 sccm, and the volume ratio of nitrogen to hydrogen in the second atmosphere is 99:1.

[0072] Example 3:

[0073] The difference from Example 1 is that in the second step, the volume ratio of hydrogen to argon is 20:80, the discharge frequency of the pulsed plasma is 1 kHz, the pulse duty cycle is 50%, and the discharge power is 500 W; in the third step, the flow rate of the first atmosphere is 50 sccm, the volume ratio of ammonia to nitrogen in the first atmosphere is 80:20, the heating rate is 5℃ / min, the second temperature is 320℃, and the reaction time is 30 min; in the fourth step, the flow rate of the second atmosphere is 800 sccm, and the volume ratio of nitrogen to hydrogen in the second atmosphere is 90:10.

[0074] Example 4:

[0075] The difference from Example 1 is that in the first step, one-dimensional MoO3 nanoribbons (aspect ratio = 47) are used.

[0076] Example 5:

[0077] The difference from Example 1 is that in the first step, one-dimensional MoO3 nanoribbons (aspect ratio = 23) are used.

[0078] Comparative Example 1:

[0079] The difference from Example 1 is that, in the first step, commercially available blocky MoO3 is used as a precursor.

[0080] Comparative Example 2:

[0081] The difference from Example 1 is that in the third step, the heating rate is 0.5℃ / min.

[0082] Comparative Example 3:

[0083] The difference from Example 1 is that in the third step, the heating rate is 10°C / min.

[0084] Comparative Example 4:

[0085] The difference from Example 1 is that in the third step, the second temperature is 250°C.

[0086] Comparative Example 5:

[0087] The difference from Example 1 is that in the third step, the second temperature is 350°C.

[0088] Comparative Example 6:

[0089] The difference from Example 1 is that in the third step, the reaction time at the second temperature is 180 min.

[0090] Comparative Example 7:

[0091] The difference from Example 1 is that in the fourth step, the flow rate of N2 is 100 sccm.

[0092] Comparative Example 8:

[0093] The difference from Example 1 is that in the fourth step, the flow rate of N2 is 900 sccm.

[0094] Comparative Example 9:

[0095] The difference from Example 1 is that the first atmosphere is changed to a mixture of hydrogen and nitrogen.

[0096] Comparative Example 10:

[0097] The difference from Example 1 is that the second step is not performed.

[0098] This application uses the modified products obtained in Examples 1-5 and Comparative Examples 1-10 as electrode active materials in lithium-ion batteries, including: using the obtained modified molybdenum trioxide as the positive electrode active material, mixing it with conductive carbon black (Super P) and binder (PVDF) at a mass ratio of 7:2:1, adding NMP and grinding into a slurry, coating it onto an aluminum foil current collector, vacuum drying it at 80~120℃ for 12~24 h, and then cutting it into positive electrode sheets with a diameter of 12~16 mm. Using a lithium metal sheet as the counter electrode, Celgard 2400 as the separator, and 1M LiPF6 / EC:DMC:DEC (volume ratio 1:1:1) as the electrolyte, CR2032 coin cells are assembled in an argon glove box.

[0099] The testing method for this application is as follows:

[0100] 1. Characterization of one-dimensional nanoribbons: The morphology and aspect ratio of the one-dimensional nanoribbons were analyzed by scanning electron microscopy, and the intensity ratio of the diffraction peaks was analyzed by X-ray diffraction. (040) / I (110) As the molybdenum trioxide precursor of this application, it must satisfy the following requirements: aspect ratio of one-dimensional nanoribbons ≥ 20, or further, the diffraction peak intensity ratio I. (040) / I (110) ≥30.

[0101] 2. Characterization of oxygen vacancies: MoO2 was analyzed by X-ray photoelectron spectroscopy. y The valence state of Mo in (2 < y ≤ 3); when there is a Mo element with a valence of +5 and / or +4, it indicates that MoO y There are oxygen vacancies, so 2 < y < 3.

[0102] 3. Crystal structure characterization: X-ray diffraction analysis was performed on the diffraction peak 2θ angle, full width at half maximum (FWHM), and integrated area of ​​the (040) crystal plane. The MoO2 to be tested was analyzed. y Based on the X-ray diffraction pattern of (2<y≤3), the MoO2 to be measured is defined. y The 2θ angle value of the diffraction peak of the (040) crystal plane is A, and the 2θ angle value of the diffraction peak of the (040) crystal plane of the MoO3 precursor is B. Calculate the AB value. When AB is positive, it indicates that the diffraction peak of the (040) crystal plane has shifted to a higher angle, and the interlayer spacing has decreased; when AB is negative, it indicates that the diffraction peak has shifted to a lower angle, and the interlayer spacing has increased. Define the MoO2 to be tested... y The full width at half maximum (FWHM) of the diffraction peak on the (040) crystal plane of the MoO3 precursor is M, and the FWHM of the diffraction peak on the (040) crystal plane of the MoO3 precursor is N. The M / N ratio is calculated. When M / N > 1, it indicates that the diffraction peak has broadened, and defects have been introduced into the lattice. When M / N is close to 1, it indicates that the lattice order remains intact. The MoO3 to be tested is defined as... y The strongest peak integrated area of ​​the (040) crystal plane is K, and the strongest peak integrated area of ​​the (040) crystal plane of the MoO3 precursor is L. The K / L ratio is calculated. When K / L < 1, it indicates a decrease in crystallinity; when K / L is close to 1, it indicates that the crystallinity remains essentially unchanged. Combining the above three parameters, when AB is positive, M / N > 1, and K / L < 1, and the XRD pattern still shows the characteristic diffraction peaks of the α-MoO3 orthorhombic crystal system (PDF#05-0508), it indicates that the MoO3 to be tested... y It has the phase structure characteristics of "crystal shrinkage, defect introduction but long-range ordered framework not destroyed".

[0103] 4. Powder conductivity test: The MoO2 to be tested is placed in the powder... yThe powder was prepared and pressed into 13 mm diameter discs under 10 MPa pressure. The surface resistivity R was measured at room temperature using the four-probe method. The conductivity (S / cm) of the compacted powder was calculated using the formula σ=L / (R·A) based on the sample thickness L and cross-sectional area A.

[0104] 5. Carrier Concentration Test: A Hall effect tester based on the van der Bauer method was used. The sample powder was pressed into a dense disc with a diameter of 10 mm to 13 mm and a thickness of 0.52 mm under a pressure of 10 MPa to 20 MPa, and ohmic contact electrodes were prepared at the four corners of the sample. The magnetic field strength was set to 0.1 T to 1.0 T (permanent magnet or electromagnet), the test temperature was room temperature (300 K), and a constant current of 1 μA to 10 mA was applied to measure the Hall voltage V of the sample. H and resistivity ρ. Based on the Hall coefficient R... H =V H ·d / (I·B) (where d is the sample thickness, I is the test current, and B is the magnetic field strength), according to the formula n=1 / (e·|R H |) Calculate the carrier concentration n (cm³) -3 ), where e is the elementary charge (1.602 × 10⁻⁶). -19 C). Each sample was tested at least at three different locations, and the average value was taken as the final carrier concentration.

[0105] 6. Specific capacity test: Battery at 1.5~3.5 V vs. Li / Li + The first discharge specific capacity (mAh / g) at a 0.1 C rate range.

[0106] 7. Initial Coulombic Efficiency Test: The battery undergoes its first charge and discharge at a 0.1 C rate (voltage window 1.5~3.5 V vs. Li / Li). + First-cycle coulombic efficiency (ICE) = First-cycle discharge specific capacity / First-cycle charge specific capacity × 100%.

[0107] 8. EIS Impedance Rct Test: The AC impedance of the battery was measured at the open circuit potential after 10 cycles at 0.1 C, with a frequency of 100 kHz to 0.01 Hz and an amplitude of 5 mV. The equivalent circuit was fitted to the Nyquist plot using ZView software. [R] s +(R ct / / CPE)+W], the semi-circular diameter in the mid-to-high frequency region is the charge transfer resistance R. ct (Ω).

[0108] 9. 1 mV / s pseudocapacitive contribution rate: Measured using a multi-sweep cyclic voltammetry method combined with the Dunn current separation method. CV curves were tested within a fixed potential window from 0.1 mV / s to 1.0 mV / s. At each potential point, the relationship between the total current and the sweep rate was established as i(v) = k1v + k2v. 1 / 2 By linear fitting i(v) / v 1 / 2 = k1v 1 / 2 +k2 extracts the surface control coefficient k1, and calculates the capacitive current i. cap (V)=k1v; Finally, a single scan branch is selected for i. cap The ratio of (V) to the absolute value of the original total current, obtained by numerical integration over the potential interval, is... This is the contribution rate of the pseudocapacitance at that scan rate.

[0109] Table 1. Precursor, modified product, and application performance test results of Examples 1-5 and Comparative Examples 1-10 of this application.

[0110]

[0111] As shown in Table 1, the modified molybdenum trioxide prepared in Examples 1-3 of this application all retained the one-dimensional nanoribbon morphology (the aspect ratio after modification was 68~70), and XRD phase analysis showed that they were all α-MoO3 orthorhombic crystal system, with no MoO2 or other impurity phases detected; XPS valence state analysis also detected Mo. 6+ Mo 5+ and Mo 4+ This indicates the successful introduction of oxygen vacancies. Regarding structural parameters, AB values ​​are all positive (0.063~0.144°), M / N ratios are all greater than 1 (1.247~1.542), and K / L ratios are all less than 1 (0.413~0.421), exhibiting characteristics of a single-crystal defect state characterized by "crystal shrinkage, defect introduction, decreased crystallinity but maintained long-range ordered framework." In terms of electrochemical performance, the modified molybdenum trioxide powder prepared in Examples 1-3 of this application achieves a conductivity of 5.0 × 10⁻⁶. -3 S / cm ~ 8.0 × 10 -3 S / cm, carrier concentration reaches 2.2×10 19 cm -3 ~3.5×10 19 cm -3 The initial discharge specific capacity is 268 mAh / g~275 mAh / g, the initial efficiency is 84%~89%, the EIS impedance Rct is 76 Ω~84 Ω, and the pseudocapacitance contribution rate at 1 mV / s is 70%~78%, exhibiting excellent electrochemical performance. Example 1 is provided as an example; please refer to the relevant documentation. Figure 1SEM images show that the modified product retains the complete one-dimensional nanoribbon morphology. The nanoribbons are axially continuous and without fracture fragments, indicating that the heating strategy with the preset heating rate effectively avoids brittle fracture caused by thermal stress. Simultaneously, the thermal shock during rapid cooling did not damage the morphology, and the one-dimensional nanoribbon morphology was well preserved. Please refer to [further details needed]. Figure 2 The XPS energy dispersive spectroscopy (EDS) spectrum of Mo 3d shows that, after peak splitting, Mo also exists. 6 + Mo 5+ and Mo 4+ The characteristic bimodal structure and the formation of mixed valence states confirm the presence of oxygen vacancies (MoO₂). y The presence of (2 < y < 3) in this defect state structure provides additional electronic transition channels, thereby improving the intrinsic conductivity of the material; please refer to [further details needed]. Figure 3 In the XRD pattern of Example 3, the (040) crystal plane diffraction peak shifts to a higher angle (AB=0.063°) compared to the precursor, the full width at half maximum (FWHM) increases (M / N=1.247), and the integral area decreases (K / L=0.421), indicating that the interplanar spacing is reduced and defects are effectively introduced. At the same time, the characteristic diffraction peaks of the α-MoO3 orthorhombic crystal system (PDF#05-0508) are still clearly present in the pattern, proving that the long-range ordered quasi-single crystal framework has not been destroyed. This structural feature is beneficial to maintaining structural stability while improving electrochemical activity.

[0112] Furthermore, Examples 4 and 5 used MoO3 precursors with one-dimensional nanoribbon aspect ratios of 47 and 23, respectively (resulting in modified MoO3 with one-dimensional nanoribbon aspect ratios of 45 and 23). Based on this, Example 1 of this application used a MoO3 precursor with one-dimensional nanoribbon aspect ratio of 72 (resulting in modified MoO3 with one-dimensional nanoribbon aspect ratio of 68). The modified MoO3 obtained in Example 1 had a higher initial discharge specific capacity, lower EIS impedance Rct, and higher 1 mV / s pseudocapacitance contribution rate when used in a battery. This indicates that the longer the aspect ratio of the one-dimensional MoO3 nanoribbons, the better the electrochemical performance of the obtained modified molybdenum trioxide material.

[0113] Compared to Embodiment 1 of this application, please refer to the following: Figure 4 Comparative Example 1 uses commercially available bulk MoO3 as a precursor, whose XRD pattern shows almost no {0k0} preferred orientation characteristic peaks, and no characteristic crystal plane shift occurs after the same processing. Therefore, this application ensures that the molybdenum trioxide precursor has a high proportion of {0k0} crystal plane exposure by controlling the aspect ratio of the one-dimensional nanoribbons of the MoO3 precursor (or further controlling its diffraction peak intensity ratio) within a preset range. This is beneficial for the subsequent ammonia treatment to directionally control this crystal plane family, avoiding the limitation of crystal plane control caused by bulk materials without preferred orientation.

[0114] Compared to Embodiment 1 of this application, please refer to the following: Figure 5 The heating rate of Comparative Examples 2-3 exceeded the preset range. One-dimensional nanoribbons are brittle. When the temperature rises too fast (>5℃ / min), internal thermal stress will accumulate, causing the nanoribbons to break into fragments along the axial direction. When the temperature rises too slowly (<1℃ / min), ammonia gas is wasted and energy consumption is increased. It is also easy to generate an anomalous MoO3 phase, which is mainly manifested as the splitting of the {0k0} characteristic crystal plane, the rightward shift of the (110) crystal plane diffraction peak and the leftward shift of the (021) crystal plane diffraction peak, resulting in poor performance when used as an electrode active material.

[0115] Compared to Embodiment 1 of this application, please refer to the following: Figure 6 In Comparative Examples 4-5, the second temperature exceeds the preset range. When the second temperature is too low (<280℃), the reaction kinetics are insufficient and the reaction may not occur. When the second temperature is too high (>320℃), it will lead to over-reduction and generate impurity phases that do not have the orthorhombic α-MoO3 crystal system framework, resulting in poor performance when used as an electrode active material.

[0116] Compared to Embodiment 1 of this application, please refer to the following: Figure 7 In Comparative Example 6, the reaction time at the second temperature exceeded the preset range. When the reaction time at the second temperature was too long (>90 min), the diffusion reaction reached its upper limit. Similar to Comparative Example 2, which easily generates anomalous MoO3, the main manifestations were that after the splitting of the {0k0} characteristic crystal plane, the low-angle diffraction peaks gradually increased while the high-angle diffraction peaks gradually disappeared, and the (110) crystal plane diffraction peak shifted to the right and the (021) crystal plane diffraction peak shifted to the left, resulting in poor performance when used as an electrode active material.

[0117] Compared to Example 1 of this application, the nitrogen flow rates in Comparative Examples 7-8 exceeded the preset range, which was detrimental to the maintenance of oxygen vacancies. In Comparative Example 7 (N2 flow rate < 200 sccm), slow cooling allowed sufficient relaxation time for the oxygen vacancies generated at high temperatures during the cooling process, leading to oxygen vacancy annihilation and a gradual restoration of the crystal structure to a near-precursor equilibrium state. In Comparative Example 8 (N2 flow rate > 800 sccm), rapid cooling generated severe thermal shock, causing severe axial fracture of the nanoribbons and disrupting the directional carrier transport channels. Furthermore, rapid cooling made it difficult to release the lattice stress at high temperatures, resulting in macroscopic strain and a shift in the XRD peak position due to stress. Only cooling with an appropriate nitrogen flow rate can both effectively freeze oxygen vacancies and maintain the complete conductivity of the one-dimensional nanoribbons.

[0118] Compared to Embodiment 1 of this application, please refer to the following: Figure 8In Comparative Example 9, when the first atmosphere was changed to a mixture of hydrogen and nitrogen, an effective nitriding-etching reaction could not occur. Instead, it led to expansion of the {0k0} interplanar spacing, resulting in poor performance when used as an electrode active material. These results indicate that ammonia is a key atmosphere component for achieving crystal facet shrinkage.

[0119] Compared to Example 1 of this application, Comparative Example 10 did not perform specific activation treatment on the molybdenum trioxide precursor. The lack of a pulsed plasma activation step made it impossible to create enough active sites on the {0k0} surface. The subsequent NH3 heat treatment could not complete sufficient crystal shrinkage and defect introduction within a limited time, resulting in poor performance when used as an electrode active material.

[0120] The method for preparing modified molybdenum trioxide provided in this application involves generating plasma in a reducing atmosphere to activate the molybdenum trioxide precursor at a first temperature. High-energy active particles in the plasma selectively etch oxygen atoms on the surface of nanoribbons to introduce oxygen vacancies. After plasma activation, the subsequent reaction can be completed in only 30 to 90 minutes under an ammonia atmosphere. Compared with the several hours required by traditional ammonia heat treatment, the isothermal reaction time is significantly shortened, while avoiding excessive reduction and morphology damage caused by prolonged high-temperature reaction. The activated molybdenum trioxide precursor is heated from a first temperature to a second temperature in a first atmosphere containing ammonia at a preset heating rate. This preset heating rate helps reduce the fracture of one-dimensional nanoribbons caused by excessively rapid accumulation of thermal stress, thereby helping to maintain the one-dimensional nanoribbon morphology of the molybdenum trioxide precursor. At the same time, it prevents energy waste and the risk of impurity phase formation caused by excessively slow heating. In addition, this second temperature window helps to reduce the excessive reduction of molybdenum trioxide to MoO2 or other impurity phases while introducing oxygen vacancies, thereby maintaining the α-MoO3 orthorhombic crystal system framework. After the reaction, a second atmosphere containing nitrogen at a preset flow rate is introduced for cooling. The rapid cooling effect generated by the nitrogen at this flow rate helps to prevent the oxygen vacancies generated at high temperature from annihilating during the slow cooling process, and further densifies the lattice by thermal contraction, thereby obtaining modified molybdenum trioxide with reduced interplanar spacing, defect locking, more complete morphology and less impurity phase formation.

[0121] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0122] The embodiments described above are merely illustrative of several implementations of the technical solution of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the technical solution of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for preparing modified molybdenum trioxide, characterized in that, Includes the following steps: A molybdenum trioxide precursor is provided, wherein the molybdenum trioxide precursor has a one-dimensional nanoribbon morphology and the aspect ratio of the one-dimensional nanoribbon is ≥20; Pulsed plasma is applied in a reducing atmosphere, and the molybdenum trioxide precursor is activated at a first temperature of 25°C to 150°C. The activated molybdenum trioxide precursor is heated from a first temperature to a second temperature in a first atmosphere, the first atmosphere including ammonia and nitrogen, the heating rate is 1℃ / min~5℃ / min, the second temperature is 280℃~320℃, and the reaction time is 30 min~90 min to prepare an intermediate. The intermediate is cooled by introducing a second atmosphere, which includes nitrogen and hydrogen, at a flow rate of 200 sccm to 800 sccm, in order to prepare the modified molybdenum trioxide.

2. The preparation method according to claim 1, characterized in that, The flow rate of ammonia in the first atmosphere is 20 sccm to 50 sccm.

3. The preparation method according to claim 1, characterized in that, In the first atmosphere, the volume ratio of ammonia to nitrogen is ≥4.

4. The preparation method according to claim 1, characterized in that, The preparation method satisfies at least one of the following conditions: (1) The discharge frequency of the pulsed plasma is 1 kHz to 100 kHz, the pulse duty cycle is 5% to 50%, and the discharge power is 10 W to 500 W; (2) The pressure of the reducing atmosphere is 10 Pa~10 Pa. 5 Pa; (3) The reducing atmosphere includes hydrogen and an inert gas, wherein the volume percentage of hydrogen is 1% to 20%; (4) The activation time is 10 s to 60 s.

5. The preparation method according to claim 1, characterized in that, The molybdenum trioxide precursor also satisfies the following condition: in the X-ray diffraction pattern, the diffraction peak intensity is higher than I. (040) / I (110) ≥30.

6. The preparation method according to claim 1, characterized in that, The preparation method satisfies at least one of the following conditions: (1) In the second atmosphere, the volume ratio of nitrogen to hydrogen is ≥9; (2) Before introducing the second atmosphere, the preparation method further includes: separating the intermediate from the first atmosphere.

7. A modified molybdenum trioxide, characterized in that, The modified molybdenum trioxide is prepared by the preparation method according to any one of claims 1-6; The modified molybdenum trioxide retains the one-dimensional nanoribbon morphology; The modified molybdenum trioxide comprises defect-state MoO with a long-range ordered lattice framework and oxygen vacancies. 3-x , 0 < X ​​< 1.

8. The modified molybdenum trioxide as described in claim 7, characterized in that, The modified molybdenum trioxide satisfies the following condition: in the X-ray photoelectron spectroscopy, the valence state of molybdenum includes +6, +5 and / or +4.

9. The modified molybdenum trioxide as described in claim 7, characterized in that, The modified molybdenum trioxide satisfies at least one of the following conditions: (1) In the X-ray diffraction pattern, the 2θ angle value of the diffraction peak of the (040) crystal plane of the modified molybdenum trioxide is defined as A, and the 2θ angle value of the diffraction peak of the (040) crystal plane of the molybdenum trioxide precursor is defined as B, 0.060≤AB≤0.145; (2) In the X-ray diffraction pattern, the full width at half maximum (FWHM) of the diffraction peak of the (040) crystal plane of the modified molybdenum trioxide is defined as M, and the full width at half maximum (FWHM) of the diffraction peak of the (040) crystal plane of the molybdenum trioxide precursor is defined as N, 1.240≤M / N≤1.545; (3) In the X-ray diffraction pattern, the strongest peak integrated area of ​​the (040) crystal plane of the modified molybdenum trioxide is defined as K, and the strongest peak integrated area of ​​the (040) crystal plane of the molybdenum trioxide precursor is defined as L, 0.410≤K / L≤0.

425.

10. The application of the modified molybdenum trioxide as described in any one of claims 7-9 in the preparation of electrode active materials, wherein the electrode active material has pseudocapacitive energy storage characteristics.

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