Preparation method of vanadium-based positive electrode material

Abstract

The embodiment of the specification provides a preparation method of a vanadium-based positive electrode material, and the preparation method comprises the following steps: dissolving sodium vanadate in a solvent to obtain a sodium vanadate solution; adding a manganese chloride solution into the sodium vanadate solution to obtain a mixed solution; carrying out a hydrothermal reaction under a first preset condition and cooling to obtain a precipitate; cleaning and drying the precipitate to obtain an intermediate; and sintering the intermediate under a second preset condition, and grinding to obtain the vanadium-based positive electrode material. The vanadium-based positive electrode material prepared by the embodiment of the specification is of an intercalation structure, the interlayer spacing of the vanadium-based positive electrode material can be effectively increased, the interlayer stability of the positive electrode material is improved, and the battery performance is further improved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a vanadium-based positive electrode material and a preparation method thereof. Background Art

[0002] The lack of battery life of implantable medical devices has become a key issue in current research. In order to solve this problem, it is crucial to develop rechargeable implantable micro-energy systems with longer life, higher efficiency and greater flexibility. Aqueous zinc-ion batteries are considered to be the most promising energy storage systems for medical electronic devices due to their low cost, aqueous electrolytes, non-toxicity and safe battery manufacturing process. However, aqueous zinc-ion batteries still face problems of unstable layered structure and capacity attenuation at low current in medical applications. Therefore, it is necessary to provide a vanadium-based positive electrode material and a preparation method thereof to improve the interlayer structure stability of the positive electrode material and improve the long-cycle stability. Summary of the invention

[0003] The embodiment of the present specification provides a method for preparing a vanadium-based positive electrode material, the preparation method comprising: dissolving sodium vanadate in a solvent to obtain a sodium vanadate solution; adding a manganese chloride solution to the sodium vanadate solution to obtain a mixed solution; performing a hydrothermal reaction under a first preset condition and cooling to obtain a precipitate; washing and drying the precipitate to obtain an intermediate; sintering the intermediate under a second preset condition and grinding to obtain a vanadium-based positive electrode material.

[0004] In some embodiments, the step of adding manganese chloride to the sodium vanadate solution to obtain a mixed solution comprises: adding the manganese chloride solution to the sodium vanadate solution under stirring to obtain a preliminary mixed solution; and adding an acid solution to the preliminary mixed solution to adjust the pH value of the preliminary mixed solution to obtain the mixed solution.

[0005] In some embodiments, the first preset conditions include: a temperature of 180° C. and a reaction time of 18 hours.

[0006] In some embodiments, the second preset conditions include: a temperature of 200° C. and a reaction time of 2 hours.

[0007] In some embodiments, the vanadium-based positive electrode material is an intercalation structure, and the intercalation structure includes a host structure and an interlayer structure, wherein the interlayer structure enables the interlayer spacing of the host structure to meet a preset spacing condition.

[0008] In some embodiments, the interlayer structure is composed of manganese-oxygen bonds formed by the combination of manganese elements and oxygen elements.

[0009] In some embodiments, the atomic ratio of the manganese element in the vanadium-based positive electrode material is 1 at % to 3 at %.

[0010] In some embodiments, the interlayer structure increases the interlayer spacing of the host structure by more than 1.2 times.

[0011] In the embodiments of the present specification, due to the introduction of manganese elements and the control of the hydrothermal reaction conditions and the sintering treatment conditions, the manganese elements are combined with the oxygen elements to form a Mn-O bond structure, and are intercalated into the vanadium pentoxide base structure to form an intercalation structure, which greatly increases the interlayer spacing of the vanadium pentoxide, thereby being able to accommodate more zinc ions to increase the battery capacity; at the same time, the intercalated Mn ions play a role in enhancing oxygen retention and delaying the degradation of the layered structure during the cycle, thereby effectively inhibiting the degradation of the layered structure and improving the cycle retention rate, thereby correspondingly improving the battery performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0013] Figure 1 is a flow chart of an exemplary method for preparing a vanadium-based positive electrode material according to some embodiments of the present specification.

[0014] Figure 2 Schematic diagram of the structure of an exemplary vanadium-based positive electrode material according to some embodiments of the present specification.

[0015] Figure 3 is a morphology image of an exemplary vanadium-based positive electrode material according to some embodiments of the present specification.

[0016] Figure 4 These are morphological structure images and XRD test results of exemplary vanadium-based positive electrode materials shown in some embodiments of this specification.

[0017] Figure 5 is an energy dispersive spectroscopy (EDS) distribution diagram of an exemplary vanadium-based cathode material according to some embodiments of the present specification.

[0018] Figure 6 These are the test results of the cycle retention performance of the exemplary vanadium-based positive electrode materials and ordinary vanadium-based positive electrode materials shown in some embodiments of this specification.

[0019] Figure 7 These are XPS test results of exemplary vanadium-based cathode materials and common vanadium-based cathode materials according to some embodiments of this specification.

[0020] Figure 8 CV test results of exemplary vanadium-based positive electrode materials according to some embodiments of the present specification. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0022] It should be understood that the "system", "device", "unit" and / or "module" used herein are a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0023] As shown in this specification and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0024] Flowcharts are used in this specification to illustrate the operations performed by the system according to the embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed precisely in order. Instead, the steps may be processed in reverse order or simultaneously. At the same time, other operations may also be added to these processes, or one or more operations may be removed from these processes.

[0025] Figure 1 It is a flow chart of the method for preparing vanadium-based positive electrode materials according to some embodiments of this specification. In some embodiments, process 100 can be automatically executed by a control system. For example, process 100 can be implemented by a control instruction, and the control system controls each component to complete each operation of process 100 based on the control instruction. In some embodiments, process 100 can be semi-automatically executed. For example, one or more operations of process 100 can be manually performed by an operator. In some embodiments, when completing process 100, one or more additional operations not described can be added, and / or one or more operations discussed herein can be deleted. In addition, Figure 1 The order of operations shown in is not limiting. Figure 1 As shown, process 100 may include the following steps.

[0026] Step 110, dissolving sodium vanadate in a solvent to obtain a sodium vanadate solution.

[0027] In some embodiments, the sodium vanadate may be in powder, granular, etc., and the solvent may be deionized water, purified water, etc.

[0028] In some embodiments, the container can be a centrifuge tube, a glass sample bottle (eg, a screw-cap bottle), or the like.

[0029] In some embodiments, after sodium vanadate is added to the solvent, the container is placed in a high pressure device (eg, an autoclave) and vigorously stirred for a preset time (eg, 10 minutes, 15 minutes, 20 minutes) to allow for more complete dissolution.

[0030] Step 120, adding the manganese chloride solution to the sodium vanadate solution to obtain a mixed solution.

[0031] In some embodiments, the manganese chloride solution is a pre-prepared solution, for example, a solution of manganese chloride powder dissolved in deionized water.

[0032] In some embodiments, during the process of adding the manganese chloride solution to the sodium vanadate solution, the sodium vanadate solution (or a partially mixed solution of the two) is stirred to make the mixing more complete.

[0033] In some embodiments, after adding the manganese chloride solution to the sodium vanadate solution, a portion of the acid solution (e.g., hydrochloric acid solution) is added to adjust the pH value of the mixed solution. By adjusting the pH value of the solution, the solubility of the reaction raw materials is enhanced, allowing for more complete dissolution.

[0034] As an example, under stirring, a manganese chloride solution is added to a sodium vanadate solution to obtain a preliminary mixed solution; an acid solution is added to the preliminary mixed solution to adjust the pH value of the preliminary mixed solution to obtain a mixed solution.

[0035] Step 130, performing a hydrothermal reaction under a first preset condition and cooling to obtain a precipitate.

[0036] In some embodiments, the hydrothermal reaction is carried out in a hydrothermal reaction apparatus (eg, an autoclave).

[0037] In some embodiments, after the manganese chloride solution and the sodium vanadate solution undergo a hydrothermal reaction, hydrated vanadium pentoxide in which manganese elements are embedded is generated. The hydrated vanadium pentoxide has a layered structure, and during the hydrothermal reaction, manganese ions are fixed between the layers of the layered structure through weak van der Waals interactions.

[0038] In some embodiments, the first preset condition includes a hydrothermal reaction temperature and a hydrothermal reaction time.

[0039] In some embodiments, in order to fix the manganese ions in the layered structure and obtain a product of a nanobelt structure (the nanobelt structure has a large specific surface area, which helps to better contact with the electrolyte during the battery cycle), the temperature and reaction time of the hydrothermal reaction need to be controlled. If the temperature is too low and / or the time is too short, it is difficult for the manganese ions to enter the layered structure; and if the temperature is too high and / or the time is too long, the nanobelt structure cannot be formed.

[0040] In some embodiments, the hydrothermal reaction temperature is within a preset temperature range. In some embodiments, the preset temperature range is 150°C-210°C. In some embodiments, the preset temperature range is 160°C-200°C. In some embodiments, the preset temperature range is 170°C-190°C. In some embodiments, the preset temperature range is 175°C-185°C. In some embodiments, the hydrothermal reaction temperature is 180°C.

[0041] In some embodiments, the hydrothermal reaction time is within a preset time range. In some embodiments, the preset time range is 15-22 hours. In some embodiments, the preset time range is 16-20 hours. In some embodiments, the preset time range is 17-19 hours. In some embodiments, the preset time range is 18-18.5 hours. In some embodiments, the hydrothermal reaction time is 18 hours.

[0042] In some embodiments, during the hydrothermal reaction, the reaction conditions of the hydrothermal reaction are monitored in real time (for example, the real-time reaction temperature is monitored in real time by a sensor). If the reaction conditions suddenly change (for example, suddenly change at a certain time point) or change beyond a preset range (for example, the average change within a preset time period exceeds a preset threshold), etc., the reaction conditions are adjusted in real time to ensure that the hydrothermal reaction is carried out accurately.

[0043] In some embodiments, after the hydrothermal reaction is completed, the reaction mixture may be cooled to room temperature naturally or by a cooling device.

[0044] Step 140, washing and drying the precipitate to obtain an intermediate.

[0045] After the hydrothermal reaction is completed and cooled, the obtained precipitate is washed and dried to obtain an intermediate. For example, the precipitate can be washed with deionized water and placed in a drying oven for drying.

[0046] After washing and drying, hydrated vanadium pentoxide in which manganese ions are embedded can be obtained.

[0047] Step 150, sintering the intermediate under a second preset condition and grinding it to obtain a vanadium-based positive electrode material.

[0048] In some embodiments, the sintering process is performed in a high temperature apparatus (eg, a tube furnace).

[0049] In some embodiments, the sintering process is performed under a protective atmosphere (eg, argon).

[0050] In some embodiments, the second preset condition includes a sintering process temperature and a sintering reaction time.

[0051] In some embodiments, in order to balance the sample cycle retention rate and capacity, the sintering temperature and sintering reaction time need to be controlled. If the temperature is too low and / or the time is too short, it is not conducive to enhancing the bond energy of the Mn-O bond, resulting in a decrease in the cycle retention rate; if the temperature is too high and / or the time is too long, the sample interlayer spacing will be reduced, resulting in a decrease in capacity.

[0052] In some embodiments, the sintering process temperature is within a preset temperature range. In some embodiments, the preset temperature range is 180°C-250°C. In some embodiments, the preset temperature range is 190°C-240°C. In some embodiments, the preset temperature range is 200°C-230°C. In some embodiments, the preset temperature range is 210°C-220°C. In some embodiments, the preset temperature range is 200°C-210°C. In some embodiments, the sintering process temperature is 200°C.

[0053] In some embodiments, the sintering reaction time is within a preset time range. In some embodiments, the preset time range is 1-3 hours. In some embodiments, the preset time range is 1.5-2.5 hours. In some embodiments, the preset time range is 1.8-2.2 hours. In some embodiments, the sintering time is 2 hours.

[0054] In some embodiments, during the sintering process, the reaction conditions of the sintering process are monitored in real time (for example, the real-time reaction temperature is monitored in real time by a sensor). If the reaction conditions suddenly change (for example, suddenly change at a certain time point) or change beyond a preset range (for example, the average change within a preset time period exceeds a preset threshold), etc., the reaction conditions are adjusted in real time to ensure that the sintering process is carried out accurately.

[0055] In some embodiments, after the sintering process is completed, the sintered product may be cooled to room temperature naturally or by a cooling device.

[0056] After sintering treatment, vanadium-based positive electrode material can be obtained.

[0057] The vanadium-based positive electrode material prepared by the above-mentioned preparation process is an intercalation structure, including a host structure and an interlayer structure. Specifically, the host structure is a vanadium pentoxide base structure, and the interlayer structure is composed of a manganese-oxygen bond formed by the combination of manganese and oxygen elements. Through the intercalation structure, the interlayer spacing of the host structure meets the preset spacing condition (for example, the interlayer structure expands the interlayer spacing of the host structure by more than 1.2 times).

[0058] The schematic diagram of the intercalation structure is shown in Figure 2 As shown, it can be seen that manganese and oxygen elements combine to form a manganese-oxygen bond structure and are intercalated into the vanadium pentoxide base structure, greatly increasing the interlayer spacing of vanadium pentoxide.

[0059] Due to the introduction of manganese elements and the control of hydrothermal reaction conditions and sintering treatment conditions, manganese elements combine with oxygen elements to form a Mn-O bond structure and are intercalated into the vanadium pentoxide base structure to form an intercalation structure, which greatly increases the interlayer spacing of vanadium pentoxide, thereby being able to accommodate more zinc ions to increase the battery capacity; at the same time, the intercalated Mn ions enhance oxygen retention and delay the degradation of the layered structure during the cycle, thereby effectively inhibiting the degradation of the layered structure and improving the cycle retention rate, thereby correspondingly improving the battery performance.

[0060] In some embodiments, in order to prepare a good intercalation structure, it is necessary to control the amount of manganese introduced. If the manganese content is too low, the interlayer spacing of the layered material will be reduced, thereby reducing the initial capacity; if the manganese content is too high, it will replace the zinc ions in the battery reaction process to undergo redox reaction, destroying the cycle reversibility of the battery.

[0061] In some embodiments, the atomic ratio of manganese in the vanadium-based positive electrode material is within a preset ratio range. In some embodiments, the preset ratio range is 1 at% to 3 at%. In some embodiments, the preset ratio range is 1.5 at% to 2.5 at%. In some embodiments, the preset ratio range is 1.7 at% to 2.2 at%. In some embodiments, the preset ratio range is 1 at% to 2 at%.

[0001] In some embodiments, after the vanadium-based positive electrode material is prepared, the positive electrode material may be further mixed with conductive carbon black and PVDF in a preset ratio and ground.

[0002] In some embodiments, the positive electrode material may be ground before mixing to make subsequent mixing more complete. In some embodiments, the mixing ratio of the positive electrode material to the conductive carbon black and PVDF is 8:1:1 or 7:2:1, which can be designed in combination with actual needs to ensure that the amount of active material is much higher than other substances. In some embodiments, when mixing, a certain amount of NMP solution is added so that the positive electrode material, conductive carbon black and PVDF can be more fully dissolved and mixed, which is helpful for subsequent coating treatment.

[0003] The ground mixture is applied to an electrode substrate (eg, titanium foil) and dried to obtain a positive electrode sheet of a battery.

[0004] It should be noted that the above description of the process 100 is only for example and illustration, and does not limit the scope of application of the present application. For those skilled in the art, various modifications and changes can be made to the process 100 under the guidance of the present application. However, these modifications and changes are still within the scope of the present application. Example 1

[0005] In the first step, 400 mg of Na3VO4 was dissolved in 30 mL of deionized water and stirred vigorously in an autoclave for more than 10 min.

[0006] In the second step, 10 mL of 0.1 mmol L-1 MnCl2 solution was added to the above solution under vigorous stirring, and 0.7 mL of HCl solution was added dropwise to adjust the pH to about 1. The hydrothermal reaction was carried out at 180°C for 18 h.

[0007] In the third step, after the hydrothermal reaction is completed, the reactor is taken out of the oven and cooled naturally to room temperature. The dark brown precipitate is collected, washed three times with deionized water, and dried in an oven to obtain hydrated vanadium pentoxide (MnVO) embedded with divalent Mn ions.

[0008] In the fourth step, MnVO was placed in a tubular furnace, argon was introduced, and the mixture was calcined at 200 °C for 2 h. The mixture was naturally cooled to room temperature to obtain a pre-sintered MnVO sample, which was then ground to obtain a vanadium-based positive electrode material.

[0009] The morphology pictures taken by scanning electron microscope are as follows Figure 3 Further observations using a transmission electron microscope, such as Figure 4 As shown in the figure, it can be seen that the embedding of Mn ions effectively expands the interlayer spacing of the vanadium pentoxide host structure, and the interlayer spacing of vanadium pentoxide is increased from Expand to At the same time, XRD data also confirmed this result. Figure 5This is the energy dispersive spectrum (EDS) distribution diagram of vanadium-based cathode materials. It can be seen that the vanadium, oxygen, and manganese elements that make up MnVO are evenly distributed in the image, and the corresponding energy spectrum diagram shows the peaks corresponding to vanadium, oxygen, and manganese elements (the peaks corresponding to carbon and copper elements are because the copper mesh and carbon film that carry the transmission sample contain carbon and copper elements). The results of the energy dispersive spectrum not only reflect the uniform distribution of the elements in the initial sample, but also prove the successful embedding of manganese ions.

[0010] The fifth step is to mix conductive carbon black and PVDF in a ratio of 7:2:1, add an appropriate amount of NMP solution, and perform ball milling.

[0011] In the sixth step, the mixture obtained in the previous step is coated on a titanium foil and dried to serve as the positive electrode of the battery.

[0012] The seventh step is to assemble the aqueous zinc ion battery in the order of positive electrode shell-positive electrode sheet-diaphragm-electrolyte-zinc sheet-gasket-spring-negative electrode shell, and use the battery testing system to test the long cycle performance of the assembled battery under the conditions of 0.3-1.6V 1.0A / g.

[0013] like Figure 6 As shown, the vanadium-based positive electrode material prepared in the examples of this specification has a significant improvement in the cycle retention rate. Compared with the cycle retention rate of 16.2% of ordinary vanadium-based positive electrode materials after 200 cycles, the vanadium-based positive electrode material prepared in the examples of this specification still maintains 85.8% of the capacity after 1000 cycles.

[0014] Figure 7 This is the XPS Mn2p peak data of ordinary vanadium-based positive electrode materials and vanadium-based positive electrode materials prepared in the examples of this specification. It can be seen that the peak of the Mn-O bond in the vanadium-based positive electrode material prepared in the examples of this specification has been significantly enhanced. This is attributed to the sintering treatment that strengthens the Mn-O bond, allowing the intercalated Mn ions and the O atoms in the layered structure to form a "rivet structure", thereby increasing the energy barrier for the deintercalation of Mn ions, thereby effectively preventing the irreversible deintercalation of Mn ions during the cycle.

[0015] Furthermore, the redox reaction in the pre-sintered MnvO was analyzed by CV test. Figure 8 Two pairs of peaks are shown in the figure; the redox pair of V5+ / V4+ is located at 1.15 V, while the transition of the V4+ / V3+ pair appears at about 0.75 V. The superimposed CV curves in the first three cycles imply that the pre-sintered MnVO cathode has a reversible reaction in hydrated Zn-ion batteries.

[0016] The beneficial effects that may be brought about by the embodiments of the present application include but are not limited to: due to the introduction of manganese elements and the control of hydrothermal reaction conditions and sintering treatment conditions, manganese elements are combined with oxygen elements to form a Mn-O bond structure, and are intercalated into the vanadium pentoxide base structure to form an intercalation structure, which greatly increases the interlayer spacing of vanadium pentoxide, thereby being able to accommodate more zinc ions to increase the battery capacity; at the same time, the intercalated Mn ions play a role in enhancing oxygen retention and delaying the degradation of the layered structure during the cycle process, thereby effectively inhibiting the degradation of the layered structure and improving the cycle retention rate, thereby correspondingly improving the battery performance.

[0017] It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced may be any one or a combination of the above, or any other beneficial effects that may be obtained.

[0018] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and corrections to this specification. Such modifications, improvements and corrections are suggested in this specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

[0019] At the same time, this specification uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this specification can be appropriately combined.

[0020] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this specification, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this specification. Although the above disclosure discusses some invention embodiments that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0021] Similarly, it should be noted that in order to simplify the description disclosed in this specification and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this specification, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the subject matter of this specification are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0022] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0023] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this specification are hereby incorporated by reference in their entirety. Except for application history documents that are inconsistent with or conflicting with the contents of this specification, documents that limit the broadest scope of the claims of this specification (currently or later attached to this specification) are also excluded. It should be noted that if the descriptions, definitions, and / or use of terms in the materials attached to this specification are inconsistent or conflicting with the contents described in this specification, the descriptions, definitions, and / or use of terms in this specification shall prevail.

[0024] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. A method for preparing a vanadium-based positive electrode material, characterized in that: The preparation method comprises: dissolving sodium vanadate in a solvent to obtain a sodium vanadate solution; adding a manganese chloride solution to the sodium vanadate solution to obtain a mixed solution; Performing a hydrothermal reaction under first preset conditions and cooling to obtain a precipitate; washing and drying the precipitate to obtain an intermediate; The intermediate is sintered and ground under the second preset condition to obtain a vanadium-based positive electrode material.

2. The preparation method according to claim 1, characterized in that The step of adding manganese chloride to the sodium vanadate solution to obtain a mixed solution comprises: Under stirring, adding the manganese chloride solution to the sodium vanadate solution to obtain a preliminary mixed solution; Acid solution is added to the preliminary mixed solution to adjust the pH value of the preliminary mixed solution to obtain the mixed solution.

3. The preparation method according to claim 1, characterized in that: The first preset condition includes: The temperature was 180°C and the reaction time was 18h.

4. The preparation method according to claim 1, characterized in that: The second preset condition includes: The temperature is 200°C and the reaction time is 2h.

5. The preparation method according to claim 1, characterized in that: The vanadium-based positive electrode material is an intercalation structure, which includes a host structure and an interlayer structure, wherein the interlayer structure enables the interlayer spacing of the host structure to meet a preset spacing condition.

6. The preparation method according to claim 5, characterized in that: The interlayer structure is composed of manganese-oxygen bonds formed by the combination of manganese elements and oxygen elements.

7. The preparation method according to claim 6, characterized in that: The atomic ratio of the manganese element in the vanadium-based positive electrode material is 1 at % to 3 at %.

8. The preparation method according to claim 5, characterized in that: The interlayer structure increases the interlayer distance of the host structure by more than 1.2 times.

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