Preparation method and application of porous nanocubic bimetallic selenide sodium ion battery negative electrode material
By preparing nanocubic bimetallic selenide materials, the problems of volume expansion and poor cycle performance of sodium-ion battery anode materials were solved, achieving high specific capacity and excellent cycle stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEILONGJIANG UNIV
- Filing Date
- 2025-01-26
- Publication Date
- 2026-07-21
AI Technical Summary
Sodium-ion battery anode materials suffer from severe volume expansion and poor cycle stability, which limits the battery's efficiency and cycle life.
A method for preparing nanocubic bimetallic selenide materials was adopted, which formed a porous structure through hydrothermal reaction, thereby increasing the specific surface area and porosity of the material and improving the Na+ transport rate and electrochemical activity.
It effectively suppressed the volume expansion problem, improved the specific capacity and cycle stability of sodium-ion batteries, and extended the battery's lifespan.
Smart Images
Figure CN119954107B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of sodium-ion battery technology, specifically relating to a method for preparing a nano cubic bimetallic selenide material and its application. Background Technology
[0002] With the continuous growth of global energy demand and the rapid development of renewable energy, the importance of energy storage technology is becoming increasingly prominent. Sodium-ion batteries, as an emerging energy storage technology, have attracted widespread attention due to their advantages such as high energy density, abundant resources, and low cost. However, sodium-ion batteries still face many challenges in practical applications, the most critical of which is the performance of the anode material.
[0003] Among traditional sodium-ion battery anode materials, metal selenides are considered a highly promising candidate due to their excellent electrochemical activity and high theoretical specific capacity. However, metal selenides exhibit significant volume expansion during charge and discharge, resulting in poor cycle stability and greatly limiting battery efficiency and cycle life.
[0004] Porous nanocube structures possess a large specific surface area and good porosity, which can effectively mitigate volume expansion during charge and discharge processes, increase active sites, and improve Na+. + This improves the transmission rate and electrochemical activity of the electrode materials, thus extending the cycle life of the battery. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing nano-cubic bimetallic selenide materials and their application in sodium-ion batteries, so as to solve the problems of low specific capacity, volume expansion and poor cycle performance of current sodium-ion battery anode materials mentioned in the background art, and improve the overall performance of sodium-ion batteries.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A method for preparing a nanocubic bimetallic selenide material, characterized by comprising the following steps:
[0008] 1) Weigh out cobalt salt and sodium citrate in a molar ratio of 0.7-1.2:1, dissolve them in deionized water, and after stirring and mixing until fully dissolved, obtain solution A;
[0009] 2) Weigh out potassium ferricyanide or potassium ferrous cyanide and dissolve it in deionized water to form solution B;
[0010] 3) Slowly add the B solution to the A solution, mix thoroughly, stir magnetically, let stand, collect the precipitate by centrifugation, wash with deionized water and ethanol, dry, and obtain purple K2CoFe(CN)6.
[0011] 4) Weigh out the selenium powder and reducer and mix them to obtain a selenium source solution;
[0012] 5) The K2CoFe(CN)6 is mixed with the selenium source solution and stirred to form a mixed solution. Selenization is then carried out through a hydrothermal reaction to obtain the porous nanocubic bimetallic selenide material.
[0013] In step 1), the cobalt salt is a cobalt hydrochloride, nitrate, or sulfate.
[0014] Specifically, the cobalt hydrochloride, nitrate, or sulfate is cobalt chloride, cobalt nitrate, or cobalt sulfate.
[0015] As a further aspect of the present invention: in step 4), the reducing agent is sodium borohydride or hydrazine hydrate.
[0016] As a further aspect of the present invention: in step 1), the dispersion concentration of the cobalt salt in deionized water is 0.04-0.08 mol / L. -1 .
[0017] As a further aspect of the present invention: in step 1), the stirring temperature is 10-30℃.
[0018] As a further aspect of the present invention: in step 2), potassium ferrocyanide or potassium ferrocyanide is dissolved in deionized water at a concentration of 0.025-0.06 mol / L. -1 .
[0019] As a further aspect of the present invention: in step 3), the rate at which solution B is added to solution A is 3-5 drops per second.
[0020] As a further embodiment of the present invention: in step 3), the magnetic stirring temperature is 10-30℃ and the stirring time is 2-24 hours.
[0021] As a further embodiment of the present invention: in step 4), the mass ratio of selenium powder to reducing agent is 1:1-3.
[0022] As a further embodiment of the present invention: in step 4), the stirring temperature is 10-30℃, the stirring time is 2-5 hours, and the stirring process requires nitrogen protection to isolate the air.
[0023] As a further aspect of the present invention: in step 5), the mass ratio of K2CoFe(CN)6 to selenium powder is 0.75-1.5:1.
[0024] As a further embodiment of the present invention: In step 5), the conditions for hydrothermal selenization are as follows: weigh the K2CoFe(CN)6 and add it to the selenium source solution, stir for 1-2 hours, and then place it in a polytetrafluoroethylene reactor. The reaction temperature is 150-220℃ and the reaction time is 8-24 hours. Porous nanocubic bimetallic selenide material is obtained through hydrothermal reaction.
[0025] This invention also provides the application of the preparation method of the aforementioned porous nanocubic bimetallic selenide material in the preparation of sodium-ion battery products.
[0026] Compared with the prior art, the beneficial effects of the present invention are:
[0027] The porous nanocubic bimetallic selenide prepared by this invention retains the original cubic structure while exhibiting porous characteristics, increasing the specific surface area, improving porosity, and adding active sites to accelerate Na+ metabolism. + Diffusion kinetics improve conductivity and enhance sodium storage capacity, facilitating better insertion and extraction of sodium ions and effectively suppressing and mitigating the problem of volume expansion.
[0028] The raw materials used in this invention are inexpensive and readily available, the process parameters are simple and controllable, and it is environmentally friendly, facilitating technology promotion. The porous nanocubic bimetallic selenide material prepared by the described method, through multiple combined effects, solves the problem of low specific capacity in sodium-ion battery anode materials, effectively improves the poor cycle performance of the battery, and extends its service life. This has positive significance for the industrialization of sodium-ion batteries and has broad market prospects. Attached Figure Description
[0029] Figure 1 a is the XRD pattern of K2CoFe(CN)6 prepared in this invention.
[0030] Figure 1 b is the XRD pattern of the porous nanocubic bimetallic selenide prepared in this invention.
[0031] Figure 2 a is a scanning electron microscope (SEM) image of K2CoFe(CN)6 prepared in this invention.
[0032] Figure 2 b is a scanning electron microscope (SEM) image of the porous nanocubic bimetallic selenide prepared in this invention.
[0033] Figure 3 The graph shows the cycling performance of the porous nanocubic bimetallic selenide material of Example 1 of the present invention at a current density of 0.1 A / g.
[0034] Figure 4The graph shows the cycling performance of the porous nanocubic bimetallic selenide material of Example 1 of the present invention at a current density of 5 A / g.
[0035] Figure 5 This is a charge-discharge curve of the porous nanocubic bimetallic selenide material in Example 1 of the present invention for the first five cycles.
[0036] Figure 6 This image shows a comparison of the current density and initial capacity of the porous nanocubic bimetallic selenide material prepared in this invention with existing sodium-ion battery selenide anode materials. The comparison demonstrates that the porous nanocubic bimetallic selenide material prepared in this invention exhibits a higher initial capacity compared to other selenides used in sodium-ion battery anodes. [The porous nanocubic bimetallic selenide material prepared in this invention has a current density and initial capacity at 100 mA g⁻¹.] -1 The initial capacity at the current density is 707.5 mAh g. -1 At 5000mAg -1 The initial capacity at high current density is 527.73 mAh g. -1 ZnSe / CoSe at 500 mAg -1 At the current density, the initial capacity is 547.1 mAh g. -1 (Reference Small, 2022, 18(28):e2202582), NiSe2@rGO at 5000 mA g -1 At current density, the initial capacity is 478 mAh g. -1 (Reference ACS Applied Materials & Interfaces, 2017, 9(1): 311-316), VSe2@PPy at 1000mAg -1 At the current density, the initial capacity is 471.36 mAh g. -1 (Reference ACS nano, 2022, 16(5):7772-7782), Nb2Se9 at 100 mAg -1 At the current density, the initial capacity is 618.87 mAh g. -1 (Reference Energy & Fuels, 2021, 35(14): 11563-11571), NiSe2 at 100 mAg -1 At current density, the initial capacity is 535 mAh g. -1 (Reference Materials Today Physics, 2022, 22:100593), Cu2Se@PPy at 1000 mAg -1 At the current density, the initial capacity is 324.8 mAh g. -1(Reference: Chemical Engineering Journal, 2022, 433: 134477), ZnSe@C@rGO at 100mAg -1 At the current density, the initial capacity is 503.1 mAh g. -1 (Reference: Journal of Energy Chemistry, 2021, 54: 124-130), WSe2 at 200 mAg -1 At the current density, the initial capacity is 468.2 mAh g. -1 (Reference Tungsten, 2024, 6(1): 248-258), Sn3Se5@PPy at 5000mAg -1 At the current density, the initial capacity is 258.3 mAh g. -1 (Journal of Power Sources, 2022, 552, 232210) Detailed Implementation
[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the methods of the present invention are conventional methods in the art.
[0038] Example 1
[0039] A method for preparing a porous nanocubic bimetallic selenide material, comprising the following steps:
[0040] At room temperature, 2 mmol (0.582 g) of cobalt nitrate hexahydrate and 2.8 mmol (0.725 g) of sodium citrate were dissolved in 50 mL of deionized water to obtain solution A.
[0041] Dissolve 1.3 mmol (0.428 g) of potassium ferricyanide in 50 mL of deionized water to obtain solution B.
[0042] Solution B was slowly added dropwise to solution A, and the mixture was magnetically stirred for 2 hours, followed by heating in a constant temperature water bath at 25-30°C for 24 hours. The resulting precipitate was collected by centrifugation, washed with deionized water and ethanol, and dried overnight at 80°C to obtain purple K₂CoFe(CN)₆. Figure 1 a is the X-ray diffraction pattern that matches the standard card. Figure 2 Image a is a scanning electron microscope (SEM) image, which shows that the product was successfully prepared.
[0043] Dissolve 0.12g sodium borohydride in 50ml deionized water. After stirring completely, add 0.04g selenium powder and stir magnetically for 5 hours under nitrogen protection to obtain a selenium source solution.
[0044] 0.03 g of K₂CoFe(CN)₆ was added to a selenium source solution and stirred for 1 hour. The mixture was then placed in a polytetrafluoroethylene (PTFE) reactor for a selenization reaction at 180 °C for 8 hours. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The resulting black product was collected by centrifugation, washed several times with deionized water and ethanol, and dried overnight at 60 °C to obtain porous nanocubic Co-Fe bimetallic selenide.
[0045] Furthermore, in this example, the aforementioned porous nanocubic cobalt-iron bimetallic selenide material is used as the anode material for electrochemical testing in a sodium-ion battery. Specifically, a sodium-ion battery is prepared using the porous nanocubic bimetallic selenide material as the anode material according to existing techniques, and its electrochemical performance is tested. The battery assembly steps are specifically described in the application example. Figure 3 and 4 As can be seen from this example, the porous nanocubic cobalt-iron bimetallic selenide material maintains a battery specific capacity of 603 mAh g after 100 cycles at a current density of 0.1 A / g. -1 The coulombic efficiency is approximately 99%, and its specific capacity still reaches 346 mAh g after 3050 cycles at a high current density of 5 A / g. -1 With a coulomb efficiency close to 100%, this porous nanocube material exhibits excellent cycling stability. Figure 5 The first five charge-discharge curves of the porous nanocubic bimetallic selenide material.
[0046] Example 2
[0047] At room temperature, 4.2 mmol of cobalt nitrate hexahydrate and 4 mmol of sodium citrate were dissolved in 50 mL of deionized water to obtain solution A.
[0048] Dissolve 1.6 mmol of potassium ferricyanide in 50 mL of deionized water to obtain solution B.
[0049] Solution B was slowly added dropwise to solution A, and the mixture was stirred for 2 hours. Then, it was heated in a constant temperature water bath at 25-30°C for 24 hours. The resulting precipitate was collected by centrifugation, washed with deionized water and ethanol, and dried overnight at 80°C to obtain purple K₂CoFe(CN)₆.
[0050] Add 2 mL of hydrazine hydrate to 50 mL of deionized water. After stirring completely, add 0.04 g of selenium powder. Stir magnetically for 5 hours under nitrogen protection to obtain a selenium source solution.
[0051] 0.03 g of K₂CoFe(CN)₆ was added to a selenium source solution and stirred for 1 hour. The mixture was then placed in a polytetrafluoroethylene (PTFE) reactor for a selenization reaction at 180 °C for 8 hours. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The resulting black product was collected by centrifugation, washed several times with deionized water and ethanol, and dried overnight at 60 °C to obtain porous nanocubic Co-Fe bimetallic selenide.
[0052] Example 3
[0053] Weigh out cobalt chloride hexahydrate and sodium citrate in a molar ratio of 0.7:1 and dissolve them in 50 mL of deionized water to obtain solution A.
[0054] Dissolve 1.3 mmol of potassium ferrocyanide in 50 mL of deionized water to obtain solution B.
[0055] Solution B was slowly added dropwise to solution A, and the mixture was stirred for 2 hours. Then, it was heated in a constant temperature water bath at 25-30°C for 24 hours. The resulting precipitate was collected by centrifugation, washed with deionized water and ethanol, and dried overnight at 80°C to obtain purple K₂CoFe(CN)₆.
[0056] Dissolve 0.12g of sodium borohydride in 50ml of deionized water. After stirring completely, add 0.04g of selenium powder and stir magnetically for 3 hours under nitrogen protection to obtain a selenium source solution.
[0057] 0.03 g of K₂CoFe(CN)₆ was added to a selenium source solution and stirred for 1 hour. The mixture was then placed in a polytetrafluoroethylene (PTFE) reactor for a selenization reaction at 180 °C for 12 hours. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The resulting black product was collected by centrifugation, washed several times with deionized water and ethanol, and dried overnight at 60 °C to obtain porous nanocubic Co-Fe bimetallic selenide.
[0058] Example 4
[0059] Weigh out cobalt chloride hexahydrate and sodium citrate in a molar ratio of 0.7:1 and dissolve them in 50 mL of deionized water to obtain solution A.
[0060] Dissolve 1.3 mmol of potassium ferricyanide in 50 mL of deionized water to obtain solution B.
[0061] Solution B was slowly added dropwise to solution A, and the mixture was stirred for 2 hours. Then, it was heated in a constant temperature water bath at 25-30°C for 24 hours. The resulting precipitate was collected by centrifugation, washed with deionized water and ethanol, and dried overnight at 80°C to obtain purple K₂CoFe(CN)₆.
[0062] Add 2 mL of hydrazine hydrate to 50 mL of deionized water. After stirring completely, add 0.04 g of selenium powder. Stir magnetically for 5 hours under nitrogen protection to obtain a selenium source solution.
[0063] 0.03 g of K₂CoFe(CN)₆ was added to a selenium source solution and stirred for 1 hour. The mixture was then placed in a polytetrafluoroethylene (PTFE) reactor for a selenization reaction at 180 °C for 12 hours. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The resulting black product was collected by centrifugation, washed several times with deionized water and ethanol, and dried overnight at 60 °C to obtain porous nanocubic Co-Fe bimetallic selenide.
[0064] Application examples
[0065] Sodium-ion battery assembly: The porous nanocubic Co-Fe bimetallic selenide, CMC (carboxymethyl cellulose), and Super P prepared in the example were mixed and ground in a mass ratio of 8:1:1 and then uniformly coated onto a 1.2 cm thick substrate. 2 The negative electrode was made of copper foil, and the positive electrode was metallic sodium. The electrolyte was a 1.0M NaPF6 DEG (diethylene glycol) / DME (dimethyl ether) solution. A CR2032 coin cell was assembled in a glove box (oxygen and moisture content both below 0.1ppm) under argon protection, using a Whatman GF / C glass fiber membrane as the battery separator. In Example 1 of this invention, the porous nanocubic cobalt-iron bimetallic selenide material assembled into a coin cell had an initial capacity of 707.5 mAh g at a current density of 0.1 A / g. -1 After 100 cycles, the battery specific capacity can still be maintained at 603mAhg. -1 The coulombic efficiency is approximately 99%, and the initial capacity is 527.73 mAh g at a high current density of 5 A / g. -1 After 3050 cycles, its specific capacity still reaches 346mAh g. -1 With a coulomb efficiency close to 100%, this porous nanocube material exhibits excellent cycling stability.
[0066] The above descriptions are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. The above descriptions are merely preferred embodiments of the present invention, and all equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the present invention.
Claims
1. A method for preparing a porous nanocubic bimetallic selenide sodium-ion battery anode material, characterized in that... Includes the following steps: (1) Weigh out cobalt salt and sodium citrate with a molar ratio of 0.7-1.2:1 and dissolve them in deionized water. After stirring evenly and dissolving completely, solution A is formed. (2) Weigh out potassium ferricyanide or potassium ferrocyanide and dissolve it in deionized water to form solution B; (3) The B solution was slowly added to the A solution, and after thorough mixing, the mixture was magnetically stirred to obtain the product K2CoFe(CN)6; (4) Weigh out the selenium powder and the reducing agent and mix them to obtain a selenium source solution; (5) Weigh the product K2CoFe(CN)6 and the selenium source solution, and obtain porous nanocubic bimetallic selenide material by hydrothermal reaction; Wherein, the cobalt salt is a cobalt hydrochloride, nitrate, or sulfate; In step (4), the reducing agent is sodium borohydride or hydrazine hydrate; In step (4), the mass ratio of selenium powder to reducing agent is 1:1-3; In step (4), the mass ratio of product K2CoFe(CN)6 to selenium powder is 0.75-1.5:1; The conditions for hydrothermal selenization are as follows: the product K2CoFe(CN)6 and the selenium source solution are dispersed in deionized water and then placed in a polytetrafluoroethylene reactor. The reaction temperature is 150-220℃ and the reaction time is 6-24 hours.
2. The method for preparing porous nanocubic bimetallic selenide materials according to claim 1, characterized in that, The cobalt-containing hydrochloride, nitrate, or sulfate is cobalt chloride, cobalt nitrate, or cobalt sulfate.
3. The method for preparing porous nanocubic bimetallic selenide material according to claim 2, characterized in that, In step (1), the cobalt salt is dispersed in deionized water at a concentration of 0.04-0.08 mol / L. -1 .
4. The method for preparing porous nanocubic bimetallic selenide material according to claim 2, characterized in that, In step (2), potassium ferricyanide or potassium ferrocyanide is dissolved in deionized water at a concentration of 0.025-0.06 mol / L. -1 .
5. The method for preparing porous nanocubic bimetallic selenide material according to claim 2, characterized in that, In step (3), the stirring temperature is 10-30℃.
6. The method for preparing porous nanocubic bimetallic selenide material according to claim 2, characterized in that, In step (3), the rate at which solution B is added to solution A is 3-5 drops / second.
7. The porous nanocubic bimetallic selenide material prepared by the method according to any one of claims 1-6 is used to prepare anode materials for sodium-ion batteries.