A bimetallic selenide nanoparticle composite material, preparation method and application

Abstract

This application relates to a bimetallic selenide nanoparticle composite material, preparation method, and application thereof, comprising: dissolving a transition metal source and a manganese source in a solvent, and preparing a transition metal-manganese polymer via a one-step hydrothermal method; mixing the transition metal-manganese polymer with selenium powder, and performing a selenization treatment under an inert gas atmosphere to obtain the bimetallic selenide nanoparticle composite material. This application can improve the conductivity of the material without carbon addition. The nanostructure accelerates sodium ion diffusion, and the fluffy volume mitigates the volume expansion caused by the reaction, thus opening up the application of selenium-based materials in sodium-ion batteries.

Description

Technical Field

[0001] The present application relates to the technical field of sodium ion battery electrode materials, and in particular to a bimetallic selenide nanoparticle composite material, a preparation method and applications thereof. Background Art

[0002] With the depletion of global fossil resources and the deterioration of the environment, people's demand for renewable clean energy is growing. The exploration and research of large-scale energy storage systems is the key to solving the problem of intermittent and discontinuous power supply of renewable clean energy. Lithium-ion batteries are an important energy storage system in energy storage devices. However, the limitations of lithium resources in the earth's crust and their uneven distribution around the world face severe demands for functions such as higher energy density and longer durability. The abundance of sodium in the earth's crust is about 1,000 times that of lithium and is evenly and widely distributed in sea samples. It has received more and more attention due to its rich sodium resources, low cost, and green and sustainable development advantages in large-scale energy storage applications of clean energy, which has promoted the rapid development of sodium-ion batteries. But Na + The ionic radius is large, and the volume changes greatly during the cycle. + The slow ion transfer kinetics, poor rate performance and unsatisfactory cycle stability have severely restricted its large-scale application. As a negative electrode material for commercial lithium-ion batteries, graphite is difficult to accommodate Na + ions, the specific capacity of sodium-ion batteries in carbonate-based electrolytes is only 40 mAh g -1 Therefore, the development of new anode materials for high-performance sodium-ion batteries is urgent.

[0003] Ideal anode materials for sodium-ion batteries should possess high conductivity, low volume expansion, and long cycle life. Consequently, metal selenides have gained increasing attention. Their narrow band gap and linewidth give them higher conductivity and larger interlayer spacing. Furthermore, the conversion / alloying reaction mechanism during sodium intercalation and deintercalation leads to high sodium storage capacity. However, selenides also have drawbacks, such as a sudden drop in specific capacity due to volume expansion during charge / discharge. Summary of the Invention

[0004] The embodiments of the present application provide a bimetallic selenide nanoparticle composite material, preparation method and application, which can improve the conductivity of the material without adding carbon. The nanostructure accelerates the diffusion of sodium ions, and the fluffy volume alleviates the volume expansion caused by the reaction, thereby expanding the application of selenium-based materials in sodium ion batteries.

[0005] In a first aspect, a method for preparing a bimetallic selenide nanoparticle composite material is provided, comprising:

[0006] A transition metal source and a manganese source are dissolved in a solvent, and a transition metal-manganese polymer is prepared by a one-step hydrothermal method;

[0007] The transition metal-manganese polymer is mixed with selenium powder, and selenization treatment is performed under the protection of an inert gas to obtain a bimetallic selenide nanoparticle composite material.

[0008] In some embodiments, the transition metal is at least one of cobalt (Co) and nickel (Ni).

[0009] In some embodiments, when the transition metal is cobalt Co, the cobalt source is at least one of cobalt nitrate, cobalt acetate, and cobalt sulfate, and the bimetallic selenide is (CoMn)Se;

[0010] When the transition metal is nickel (Ni), the nickel source is at least one of nickel nitrate, nickel acetate and nickel sulfate, and the bimetallic selenide is (NiMn)Se.

[0011] In some embodiments, the solvent is glycerol, or one of N,N-dimethylformamide and isopropyl alcohol.

[0012] In some embodiments, the volume ratio of glycerol to isopropyl alcohol is 4 to 10:15.

[0013] In some embodiments, the molar ratio of the manganese source to the transition metal source is 1:(1-3).

[0014] In some embodiments, the reaction temperature of the one-step hydrothermal method is 150-200° C., and the reaction time is 4-12 hours.

[0015] In some embodiments, the mass ratio of the transition metal-manganese polymer to selenium powder is 3:(2-3);

[0016] And / or, the selenization treatment includes: first heating to 200-300° C. and maintaining for 2-4 hours, then continuing to heat to 400-600° C. and maintaining for 1-3 hours;

[0017] and / or, the manganese source comprises at least one of manganese acetate and manganese acetylacetonate;

[0018] And / or, the inert gas includes at least one of argon and helium.

[0019] In a second aspect, a bimetallic selenide nanoparticle composite material is provided, which is prepared using any of the above-described methods for preparing a bimetallic selenide nanoparticle composite material.

[0020] In a third aspect, a method for preparing a negative electrode material for a sodium ion battery is provided.

[0021] The beneficial effects of the technical solution provided by this application include:

[0022] The embodiment of the present application can prepare a composite material in two steps, specifically including the following steps: first preparing a nanoscale transition metal-manganese polymer by a one-step hydrothermal method, and then in situ selenizing the transition metal-manganese polymer to obtain nanoparticles with a heterogeneous structure.

[0023] This method controls the volume of the composite material structure to the nanometer level. The small volume can fully infiltrate the electrolyte, shorten the diffusion channel of sodium ions, optimize the adsorption of sodium ions, and facilitate Na + The rapid transfer of ions and the resulting heterostructure increase the ion / electron diffusion rate of the electrode in redox reactions, reduce the energy barrier, and improve its intrinsic conductivity, which is of great significance in electrochemistry.

[0024] The morphology of the prepared nanoparticle composite material is porous nanospheres, which are composed of many small particles aggregated together. These small particles are not tightly arranged together, but interspersed with gaps. The fluffy volume of the bimetallic selenide formed by selenization alleviates the volume expansion caused by the reaction. Moreover, this structure allows the electrolyte and Na + It is easy to enter the interior of the nanospheres, thereby improving the cyclic stability of the composite material.

[0025] The bimetallic selenide nanoparticles prepared in this application polymerize two transition elements into uniformly dispersed nanospheres under the action of a solvent. Under high-temperature selenization, the two phase interfaces have a heterogeneous structure and have excellent conductivity in the absence of carbon incorporation.

[0026] After 100 cycles at a current density of 0.1 A / g, (CoMn)Se maintained a specific capacity of more than 595.6 mAh / g, showing excellent rate performance; after 1500 cycles at a current density of 5 A / g, (CoMn)Se maintained a specific capacity of 491 mAh / g, showing excellent cycling performance.

[0027] After 100 cycles at a current density of 0.1 A / g, (NiMn)Se maintained a specific capacity of more than 492 mAh / g, showing excellent rate performance; after 1000 cycles at a current density of 5 A / g, (NiMn)Se maintained a specific capacity of 441.2 mAh / g, showing excellent cycling performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] Figure 1 This is the XRD pattern of the (CoMn)Se nanoparticle composite material prepared in Example 1 of the present application;

[0030] Figure 2 This is the XRD pattern of the (NiMn)Se nanoparticle composite material prepared in Example 1 of the present application;

[0031] Figure 3 This is a SEM image of the Co-Mn polymer prepared in Example 1 of the present application;

[0032] Figure 4 This is a SEM image of the (CoMn)Se nanoparticle composite material prepared in Example 1 of the present application;

[0033] Figure 5 This is a SEM image of the Ni-Mn polymer prepared in Example 1 of the present application;

[0034] Figure 6 This is a SEM image of the (NiMn)Se nanoparticle composite material prepared in Example 1 of the present application;

[0035] Figure 7 TEM image of the (CoMn)Se nanoparticle composite material prepared in Example 1 of the present application;

[0036] Figure 8 TEM image of the (NiMn)Se nanoparticle composite material prepared in Example 1 of the present application;

[0037] Figure 9 Graphs showing the cycling performance of the (CoMn)Se nanoparticle composite material prepared in Example 1 of the present application, the CoSe2 nanomaterial prepared in Comparative Example 1, and the MnSe nanomaterial prepared in Comparative Example 3 at a current density of 0.1 A / g;

[0038] Figure 10 Graph showing the cycling performance of the (NiMn)Se nanoparticle composite material prepared in Example 1 of the present application, the NiSe2 nanomaterial prepared in Comparative Example 2, and the MnSe nanomaterial prepared in Comparative Example 3 at a current density of 0.1 A / g;

[0039] Figure 11Graphs showing the cycling performance of the (CoMn)Se nanoparticle composite material prepared in Example 1 of the present application, the CoSe2 nanomaterial prepared in Comparative Example 1, and the MnSe nanomaterial prepared in Comparative Example 3 at a current density of 2 A / g;

[0040] Figure 12 The cycling performance diagrams of the (NiMn)Se nanoparticle composite material prepared in Example 1 of the present application, the NiSe2 nanomaterial prepared in Comparative Example 2, and the MnSe nanomaterial prepared in Comparative Example 3 at a current density of 2 A / g are shown;

[0041] Figure 13 This is a cycling performance diagram of the (CoMn)Se nanoparticle composite material prepared in Example 1 of the present application at a current density of 5 A / g;

[0042] Figure 14 This is a cycling performance diagram of the (NiMn)Se nanoparticle composite material prepared in Example 1 of the present application at a current density of 5 A / g. DETAILED DESCRIPTION

[0043] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0044] The present invention provides a method for preparing a bimetallic selenide nanoparticle composite material, which comprises:

[0045] 101: A transition metal source and a manganese source are dissolved in a solvent, and a transition metal-manganese polymer is prepared by a one-step hydrothermal method.

[0046] In this step 101, the reaction temperature of the one-step hydrothermal method is 150-200° C., and the reaction time is 4-12 hours.

[0047] The transition metal is at least one of cobalt (Co) and nickel (Ni).

[0048] When the transition metal is cobalt Co, the transition metal-manganese polymer is a Co-Mn polymer, and the bimetallic selenide is (CoMn)Se (i.e., a CoSe2 / MnSe complex); wherein, there are multiple options for the cobalt source, for example, as an example, the cobalt source is at least one of cobalt nitrate, cobalt acetate, and cobalt sulfate.

[0049] When the transition metal is nickel Ni, the transition metal-manganese polymer is a Ni-Mn polymer, and the bimetallic selenide is (NiMn)Se (i.e., NiSe2 / MnSe complex); wherein, there are multiple options for the nickel source, for example, the nickel source is at least one of nickel nitrate, nickel acetate, and nickel sulfate.

[0050] Of course, if the transition metal source includes both a cobalt source and a nickel source, the transition metal-manganese polymer is a mixture of a Co-Mn polymer and a Ni-Mn polymer. Similarly, the bimetallic selenide is a mixture of (CoMn)Se and (NiMn)Se.

[0051] In step 101, the solvent is composed of two substances to ensure the formation of well-dispersed spherical particles during the reaction. Specifically, the solvent includes glycerol and one of N-dimethylformamide and isopropyl alcohol. For example, glycerol and isopropyl alcohol can be selected. Glycerol provides a high viscosity, which enables the formation of spherical polymers during the hydrothermal process. The volume ratio of glycerol to isopropyl alcohol is 4 to 10:15.

[0052] In step 101, there are multiple options for the manganese source. For example, the manganese source includes at least one of manganese acetate and manganese acetylacetonate. The molar ratio of the manganese source to the transition metal source is 1:(1-3).

[0053] 102: Evenly mix the transition metal-manganese polymer and selenium powder, and perform selenization treatment under the protection of an inert gas to obtain a bimetallic selenide nanoparticle composite material.

[0054] In this step 102, the mass ratio of the transition metal-manganese polymer to selenium powder is 3:(2-3).

[0055] The selenization treatment includes: firstly heating the temperature to 200-300° C. and maintaining it for 2-4 hours, then continuing heating the temperature to 400-600° C. and maintaining it for 1-3 hours.

[0056] The inert gas includes at least one of argon and helium.

[0057] The embodiment of the present application can prepare a composite material in two steps, specifically including the following steps: first preparing a nanoscale transition metal-manganese polymer by a one-step hydrothermal method, and then in situ selenizing the transition metal-manganese polymer to obtain nanoparticles with a heterogeneous structure.

[0058] This method controls the volume of the composite material structure to the nanometer level. The small volume can fully infiltrate the electrolyte, shorten the diffusion channel of sodium ions, optimize the adsorption of sodium ions, and facilitate Na +The rapid transfer of ions and the resulting heterostructure increase the ion / electron diffusion rate of the electrode in redox reactions, reduce the energy barrier, and improve its intrinsic conductivity, which is of great significance in electrochemistry.

[0059] The morphology of the prepared nanoparticle composite material is porous nanospheres, which are composed of many small particles aggregated together. These small particles are not tightly arranged together, but interspersed with gaps. The fluffy volume of the bimetallic selenide formed by selenization alleviates the volume expansion caused by the reaction. Moreover, this structure allows the electrolyte and Na + It is easy to enter the interior of the nanospheres, thereby improving the cyclic stability of the composite material.

[0060] The bimetallic selenide nanoparticles prepared in this application polymerize two transition elements into uniformly dispersed nanospheres under the action of a solvent. Under high-temperature selenization, the two phase interfaces have a heterogeneous structure and have excellent conductivity in the absence of carbon incorporation.

[0061] Example 1

[0062] A method for preparing a bimetallic selenide nanoparticle composite material comprises the following steps:

[0063] S1. Dissolve 0.5 mmol of manganese acetate and 1 mmol of cobalt nitrate in 16 ml of glycerol and 60 ml of isopropanol, stir for 30 min, transfer to a Teflon reactor, heat in an oven at 180°C for 10 h, cool naturally, and then wash, separate, and dry to obtain a Co-Mn polymer. Figure 3 As shown, it is the SEM image of Co-Mn polymer, which shows that the Co-Mn polymer is in the form of well-dispersed nanospheres with a diameter of about 500 to 800 nm;

[0064] 0.5 mmol of manganese acetate and 1 mmol of nickel nitrate were dissolved in 16 ml of glycerol and 60 ml of isopropanol, stirred for 30 min, and then transferred to a Teflon reactor. The mixture was heated in an oven at 180 °C for 10 h. After natural cooling, the Ni-Mn polymer was obtained after washing, separation, and drying. Figure 5 As shown, it is the SEM image of Ni-Mn polymer, which shows that Ni-Mn polymer is nano-spherical with a diameter of about 300 to 500 nm;

[0065] S2. The Co-Mn polymer obtained in step S1 was uniformly mixed with selenium powder in a mass ratio of 3:2, placed in a porcelain boat, heated to 300°C under high-purity argon, maintained for 4 hours, and then continued to heat to 400°C and maintained for 2 hours to obtain a (CoMn)Se nanoparticle composite material, see Figure 1 、 Figure 4 and Figure 7 As shown, the XRD pattern, SEM pattern and TEM pattern of (CoMn)Se nanoparticle composite material; Figure 1 From the X-ray diffraction pattern, we can see that the position of each peak is consistent with the diffraction peak position of the standard cards of CoSe2 and MnSe, and there are no other impurity peaks, so it is proved that the material is CoSe2 / MnSe, that is, (CoMn)Se; Figure 4 This is the microscopic morphology of (CoMn)Se nanoparticles. It can be seen that the size of the particles has not changed after selenization, but the surface of the particles has become rough. Combined with the transmission image, it can be seen that the porosity has increased after selenization, which makes it easier for sodium ions to embed and detach.

[0066] The Ni-Mn polymer obtained in step S1 was uniformly mixed with selenium powder in a mass ratio of 3:2, placed in a porcelain boat, and heated to 300°C under high-purity argon for 4 hours, then continued to heat to 400°C and maintained for 2 hours to obtain a (NiMn)Se nanoparticle composite material. Figure 2 、 Figure 6 and Figure 8 As shown in Figure 1, the XRD pattern, SEM pattern and TEM pattern of (NiMn)Se nanoparticle composite material are shown. Figure 2 From the X-ray diffraction pattern, we can see that the position of each peak is consistent with the diffraction peak position of the standard cards of NiSe2 and MnSe, and there are no other impurity peaks, so it is proved that the material is NiSe2 / MnSe, that is, (NiMn)Se; Figure 6 This is a microscopic image of (NiMn)Se nanoparticles. They are smaller than (CoMn)Se, and the surface of the particles becomes rough after selenization. The transmission image shows that the interior of the particles becomes granular after selenization, which allows for better insertion and extraction of sodium ions.

[0067] Comparative Example 1

[0068] This comparative example provides a method for preparing CoSe2 nanomaterials, which specifically includes the following steps:

[0069] S1. Dissolve 2 mmol of cobalt nitrate in 16 ml of glycerol and 60 ml of isopropanol, stir evenly for 30 min, transfer to a Teflon reactor, and hydroheat in an oven at 180°C for 10 h. After cooling naturally, wash, separate, and dry to obtain a Co nanosphere polymer.

[0070] S2. The Co nanosphere polymer material obtained in step S1 was evenly mixed with selenium powder in a mass ratio of 3:2, placed in a porcelain boat, heated to 300°C under high-purity argon, maintained for 4 hours, and then continued to heat to 400°C and maintained for 2 hours to obtain CoSe2 nanomaterial.

[0071] Comparative Example 2

[0072] This comparative example provides a method for preparing NiSe2 nanomaterials, which specifically includes the following steps:

[0073] S1. Dissolve 2 mmol of nickel nitrate in 16 ml of glycerol and 60 ml of isopropanol, stir evenly for 30 min, transfer to a Teflon reactor, and hydroheat in an oven at 180°C for 10 h. After cooling naturally, wash, separate, and dry to obtain a Ni nanosphere aggregate.

[0074] S2. The Ni nanosphere polymer material obtained in step S1 was uniformly mixed with selenium powder in a mass ratio of 3:2, placed in a porcelain boat, heated to 300°C under high-purity argon, maintained for 4 hours, and then continued to heat to 400°C and maintained for 2 hours to obtain NiSe2 nanomaterial.

[0075] Comparative Example 3

[0076] This comparative example provides a method for preparing a MnSe nanomaterial, which specifically includes the following steps:

[0077] S1. Dissolve 2 mmol of manganese acetate in 16 ml of glycerol and 60 ml of isopropanol, stir evenly for 30 min, transfer to a Teflon reactor, and hydroheat in an oven at 180°C for 10 h. After natural cooling, wash, separate, and dry to obtain a Mn nanosphere polymer.

[0078] S2. The Mn nanosphere polymer material obtained in step S1 was uniformly mixed with selenium powder in a mass ratio of 3:2, placed in a porcelain boat, heated to 300°C under high-purity argon, maintained for 4 hours, and then continued to heat to 400°C and maintained for 2 hours to obtain MnSe nanomaterials.

[0079] Application Examples

[0080] The nanomaterials prepared in Example 1 and Comparative Examples 1 to 3 were mixed with conductive carbon and carboxymethyl cellulose (CMC) in deionized water at a ratio of 7:2:1 to form a uniform slurry. The slurry was then evenly coated on a copper foil and dried in a vacuum oven at 80°C overnight. The copper foil was cut into discs with a diameter of 12 mm and a loading of 1 mg / cm 2 The electrode materials were assembled into 2032-type button cells. The separator used was Whatman GF / A, and the electrolyte system consisted of 1M sodium trifluoromethanesulfonate (NaPF6) as the solute and diethylene glycol (DME) as the solvent. All cells were allowed to rest for 12 hours before testing to ensure electrolyte penetration and stable open-circuit voltage.

[0081] The assembled button batteries were subjected to electrochemical performance tests. The test instruments used for the electrochemical performance tests are as follows: LANHE-CT2001A multi-channel battery testing system produced by Wuhan Landian Electronics Co., Ltd., with a standing time of 12 hours, a voltage window range of 0.2-2.8V, a current density range of 100-5000mAg-1, and a cycle number range of 100-1500 times.

[0082] The cycle performance of the composite materials prepared in Example 1 and Comparative Examples 1 to 3 at a current density of 2 A / g is shown in Table 1.

[0083] Table 1 Cycling performance at a current density of 2 A / g

[0084]

[0085] The bimetallic selenide (X-Mn)Se (X=Co, Ni) nanoparticle composite material prepared in this application is used as a negative electrode material for sodium ion batteries, wherein:

[0086] See also Figure 9 As shown in Figure 2, (CoMn)Se maintains a specific capacity of more than 595.6 mAh / g after 100 cycles at a current density of 0.1 A / g, showing excellent rate performance; see Figure 11 As shown in Figure 2, (CoMn)Se maintains a specific capacity of more than 515.5 mAh / g after 1000 cycles at a current density of 2 A / g, showing excellent cycling performance; see Figure 13 As shown, (CoMn)Se maintained a specific capacity of 491 mAh / g after 1500 cycles at a current density of 5 A / g, showing excellent cycling performance.

[0087] See also Figure 10 As shown in Figure 2, (NiMn)Se maintains a specific capacity of more than 492 mAh / g after 100 cycles at a current density of 0.1 A / g, showing excellent rate performance; see Figure 12 As shown in Figure 2, (NiMn)Se maintains a specific capacity of more than 457.1 mAh / g after 1000 cycles at a current density of 2 A / g, showing excellent cycling performance; see Figure 14 As shown, (NiMn)Se maintained a specific capacity of 441.2 mAh / g after 1000 cycles at a current density of 5 A / g, showing excellent cycling performance.

[0088] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0089] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0090] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for preparing a bimetallic selenide nanoparticle composite material, characterized in that: The bimetallic selenide nanoparticle composite material is applied to the negative electrode material of sodium ion batteries, and comprises: A transition metal source and a manganese source are dissolved in a solvent, and a transition metal-manganese polymer is prepared by a one-step hydrothermal method. The transition metal-manganese polymer is in the form of nanospheres. The solvent is glycerol and isopropanol, and the volume ratio of glycerol to isopropanol is 4-10:

15. The transition metal is nickel (Ni). The transition metal-manganese polymer is mixed with selenium powder in a mass ratio of 3:(2-3), and selenization is performed under inert gas protection to obtain a bimetallic selenide nanoparticle composite material, wherein the bimetallic selenide is (NiMn)Se, and the nanoparticle composite material is porous nanospheres formed by aggregation of many particles, and these particles are interspersed with gaps, so that the surface of the nanoparticle composite material is rough and the interior is granular; The selenization treatment includes: firstly heating the temperature to 200-300°C and maintaining it for 2-4 hours, then continuing to heat the temperature to 400-600°C and maintaining it for 1-3 hours.

2. The method for preparing the bimetallic selenide nanoparticle composite material according to claim 1, wherein: The nickel source is at least one of nickel nitrate, nickel acetate and nickel sulfate.

3. The method for preparing the bimetallic selenide nanoparticle composite material according to claim 1, wherein: The molar ratio of the manganese source to the transition metal source is 1:(1-3).

4. The method for preparing the bimetallic selenide nanoparticle composite material according to claim 1, wherein: The reaction temperature of the one-step hydrothermal method is 150-200° C., and the reaction time is 4-12 hours.

5. The method for preparing the bimetallic selenide nanoparticle composite material according to claim 1, wherein: The manganese source includes at least one of manganese acetate and manganese acetylacetonate; And / or, the inert gas includes at least one of argon and helium.

6. A bimetallic selenide nanoparticle composite material, characterized by: The composite material is prepared by the method for preparing the bimetallic selenide nanoparticle composite material according to any one of claims 1 to 5.

7. Use of the bimetallic selenide nanoparticle composite material as claimed in claim 6 in preparing a negative electrode material for a sodium ion battery.

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