A method for preparing a nickel-based prussian blue analogue nanoparticle

Abstract

The application discloses a preparation method of a nickel-based Prussian blue analogue nanoparticle. The preparation method comprises the following steps: under the action of ethylenediaminetetraacetate and polyvinylpyrrolidone, a water-soluble nickel salt is subjected to a hydrothermal reaction with a water-soluble ferrocyanide salt or a ferricyanide salt to obtain the nickel-based Prussian blue analogue nanoparticle. Compared with the prior art, the crystal structure of the nickel-based Prussian blue analogue nanoparticle prepared by the method is cubic phase, and the electrochemical performance of the nickel-based Prussian blue analogue nanoparticle is not only significantly better than that of the existing cubic phase nickel-based Prussian blue analogue, but also better than that of the existing monoclinic phase nickel-based Prussian blue analogue.

Description

Technical Field

[0001] This invention belongs to the field of aqueous sodium-ion battery cathode materials, specifically relating to a method for preparing nickel-based Prussian blue analog nanoparticles. Background Technology

[0002] Due to the fluctuating, intermittent, and spatially uneven distribution of renewable clean energy, large-scale energy storage systems that are safe, low-cost, and environmentally friendly are required. Therefore, aqueous alkali metal battery energy storage devices have attracted widespread attention. Among aqueous alkali metal batteries, aqueous lithium-ion batteries were the earliest to be studied. However, the high cost of aqueous lithium-ion batteries is due to the limited reserves of lithium resources (lithium abundance in the Earth's crust is only 0.0065%). Sodium reserves in the Earth's crust are far higher than lithium reserves (sodium abundance in the Earth's crust is 2.36%), and sodium ions have a higher migration rate in solution compared to lithium ions. Therefore, aqueous sodium-ion batteries have better development prospects. However, the large ionic radius and high ionization potential of sodium ions limit the available cathode materials. Prussian blue and its analogues possess advantages such as a three-dimensional framework, large lattice interstices, and high theoretical specific capacity. Therefore, Prussian blue and its analogues are materials that can be used as cathode materials in aqueous sodium-ion batteries.

[0003] Yue Xu reported a method for one-step crystallization synthesis of nickel-based Prussian blue analogues using a co-precipitation method. Adv. Energy Mater (2018, 1803158) This study uses Na4P2O7 as a chelating agent to control the crystal form of nickel-based Prussian blue analogs. The specific preparation process is as follows: 1 mmol NiCl2·6H2O and an appropriate amount of Na4P2O7 are dissolved in 20 mL of water to obtain solution A. 1 mmol Na4Fe(CN)6, 10 mmol NaCl and 0.1 g PVP-K30 are dissolved in 50 mL of water to obtain solution B. Solution A is added dropwise to solution B under stirring. The mixture is aged for 24 h. The precipitate is centrifuged, washed, and dried to obtain a monoclinic nickel-based Prussian blue analog with a specific capacity of 85.7 mAh g⁻¹. −1 When the Na4P2O7 chelating agent is not used, the resulting nickel-based Prussian blue analog crystal structure transforms into a cubic phase, but its electrochemical performance decreases significantly compared to the monoclinic phase. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing nickel-based Prussian blue analog nanoparticles. The nickel-based Prussian blue analog prepared by this method has superior electrochemical performance compared with existing cubic phase nickel-based Prussian blue analogs.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing nickel-based Prussian blue analog nanoparticles, comprising: Under the action of ethylenediaminetetraacetic acid salt and polyvinylpyrrolidone, water-soluble nickel salt reacts thermally with water-soluble ferrous cyanide salt or ferric cyanide salt to obtain the nickel-based Prussian blue analog nanoparticles.

[0006] Preferably, the water-soluble nickel salt is nickel chloride and / or nickel nitrate.

[0007] Preferably, the ethylenediaminetetraacetic acid salt includes at least one of ethylenediaminetetraacetic acid dilithium salt, ethylenediaminetetraacetic acid tetralithium salt, ethylenediaminetetraacetic acid disodium salt, ethylenediaminetetraacetic acid tetrasodium salt, ethylenediaminetetraacetic acid dipotassium salt, and ethylenediaminetetraacetic acid tetrapotassium salt.

[0008] More preferably, the molar ratio of the ethylenediaminetetraacetic acid salt to the water-soluble nickel salt is 1 to 5:1.

[0009] Most preferably, the molar ratio of the ethylenediaminetetraacetic acid salt to the water-soluble nickel salt is 1~1.2:1.

[0010] Preferably, the water-soluble ferrocyanide salt is sodium ferrocyanide and / or potassium ferrocyanide, and the water-soluble ferrocyanide salt is potassium ferrocyanide.

[0011] More preferably, the molar ratio of the water-soluble ferrocyanide or ferrocyanide to the water-soluble nickel salt is 1:1.

[0012] Preferably, the K value of the polyvinylpyrrolidone is 27-30.

[0013] More preferably, the mass ratio of the polyvinylpyrrolidone to the water-soluble nickel salt is 1 to 3:1.

[0014] Most preferably, the mass ratio of the polyvinylpyrrolidone to the water-soluble nickel salt is 1.3 to 1.5:1.

[0015] Preferably, the initial concentration of the water-soluble nickel salt in the reaction system is 0.01~0.2 mol / L.

[0016] Preferably, the hydrothermal reaction is carried out at a temperature of 80~180 ℃ for a time of 12~72 h.

[0017] Preferably, ethylenediaminetetraacetic acid salt and water-soluble nickel salt are dissolved in water to obtain solution A, and polyvinylpyrrolidone and water-soluble ferrous cyanide or ferric cyanide salt are dissolved in water to obtain solution B. Solutions A and B are mixed and placed in a reaction vessel for hydrothermal reaction. The reaction product is washed and dried to obtain the nickel-based Prussian blue analog nanoparticles.

[0018] Another object of the present invention is to provide nickel-based Prussian blue analog nanoparticles.

[0019] To achieve the above objectives, the present invention adopts the following technical solution: A nickel-based Prussian blue analog nanoparticle, characterized in that it is prepared according to the above method.

[0020] Preferably, the particle size of the nickel-based Prussian blue analog nanoparticles is no greater than 50 nm.

[0021] Another object of the present invention is to provide the use of nickel-based Prussian blue analog nanoparticles.

[0022] To achieve the above objectives, the present invention adopts the following technical solution: The use of a nickel-based Prussian blue analog nanoparticle, characterized in that the nickel-based Prussian blue analog nanoparticle as described above is used in the preparation of the positive electrode of an aqueous sodium-ion battery.

[0023] Compared with existing technologies, the nickel-based Prussian blue analog nanoparticles prepared by the method of this invention have a cubic phase crystal structure, and their electrochemical performance is not only significantly better than that of existing cubic phase nickel-based Prussian blue analogs, but also better than that of existing monoclinic phase nickel-based Prussian blue analogs. Attached Figure Description

[0024] Figure 1 The XRD and XPS spectra of the nickel-based Prussian blue analog prepared in Example 1 are shown.

[0025] Figure 2 This is a field emission scanning electron microscope image of the nickel-based Prussian blue analog prepared in Example 1.

[0026] Figure 3 These are the cyclic voltammetry curves, constant current charge-discharge curves, and Nyquist plots of nickel-based Prussian blue analogues. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0028] Example 1 Solution A is prepared by dissolving 4 mmol of nickel chloride and 4.2 mmol of disodium ethylenediaminetetraacetate in 30 mL of deionized water. Solution B is prepared by dissolving 4 mmol of potassium ferrocyanide trihydrate and 0.7 g of polyvinylpyrrolidone (K27-K30, relative molecular mass 55000) in 40 mL of deionized water. Solution A was slowly added to solution B and stirred vigorously for 10 min to form mixture C; mixture C was transferred to a hydrothermal reactor and reacted at 120 ℃ for 12 h to obtain precipitate D; After washing the precipitate D three times with water and three times with ethanol, the precipitate was vacuum filtered to obtain filter cake E. The filter cake E was placed in a forced-air drying oven and dried at 80 °C for 24 h to obtain nanoscale nickel-based Prussian blue analog (NiFeHCF).

[0029] The prepared NiFeHCF was characterized in terms of phase and morphology, and the results are as follows: Figure 1-2 As shown. like Figure 1 As shown in Figure a, the characteristic peaks of the NiFeHCF cathode material at 17.55°, 24.92°, 35.60°, 39.86°, 43.92°, 51.16°, and 57.64° correspond to the (200), (220), (400), (420), (422), (440), and (620) crystal planes, respectively. This is consistent with JCPDS No. 00-014-0291 (Ni2Fe(CN)6·xH2O), indicating that the prepared NiFeHCF has a cubic crystal structure belonging to the Fm-3m (225) space group. Further compositional analysis of NiFeHCF was performed, as shown in Figure a. Figure 1 As shown in bd, the XPS full spectrum shows that NiFeHCF contains nickel, iron, carbon, nitrogen, and oxygen elements. Figure 1 b); High-resolution Ni2p XPS and Fe2p XPS spectra show that nickel and iron in nickel-based Prussian blue both exist in +2 and +3 valence states, but the peak area and peak height of +2 valence for nickel and iron are much larger than those of +3 valence. Figure 1 This indicates that both nickel and iron primarily exist in the +2 valence state.

[0030] like Figure 2 As shown: Field emission scanning electron microscopy (FEM) images of NiFeHCF indicate that it has a cubic structure with a particle size of less than 50 nm.

[0031] Comparative Example 1 Dissolve 4 mmol of nickel chloride in 30 mL of deionized water to form solution A; Solution B is prepared by dissolving 4 mmol of potassium ferrocyanide trihydrate and 0.7 g of polyvinylpyrrolidone (K27-K30) in 40 mL of deionized water. Solution A was slowly added to solution B and stirred vigorously for 10 min to form mixture C; mixture C was transferred to a hydrothermal reactor and reacted at 120 ℃ for 12 h to obtain precipitate D; After washing the precipitate D three times with water and three times with ethanol, the precipitate was vacuum filtered to obtain filter cake E. The filter cake E was placed in a forced-air drying oven and dried at 80 °C for 24 h to obtain a nickel-based Prussian blue analog (NiFeHCF-2).

[0032] Comparative Example 2 According to the coprecipitation method reported in the literature: 1 mmol of nickel chloride hexahydrate was dissolved in 20 mL of water to form solution A, and 1 mmol of sodium ferrocyanide decahydrate, 10 mmol of sodium chloride, and 0.1 g of polyvinylpyrrolidone (K27-K30) were dissolved in 50 mL of water to form solution B. Then, under continuous stirring, solution A was slowly added dropwise to solution B at a rate of approximately 180 mL / h. −1 (i.e., 1 drop / s), after the addition is complete, a mixture C is obtained. Mixture C is aged in the dark for 24 h to obtain precipitate D. Precipitate D is washed three times each with water and ethanol, and then vacuum filtered to obtain filter cake E. Filter cake E is placed in a forced-air drying oven and dried at 80 ℃ for 24 h to obtain nickel-based Prussian blue analog (NiFeHCF-3).

[0033] Electrochemical performance testing Nickel-based Prussian blue analogues: NiFeHCF, NiFeHCF-2, and NiFeHCF-3 prepared in Example 1, Comparative Example 1, and Comparative Example 2, respectively.

[0034] 4.0 mg of a nickel-based Prussian blue analogue sample and 0.8 mg of acetylene black were weighed and ground into powder. The mixed powder was then ultrasonically dispersed in 0.4 mL of a 0.25% NAFION ethanol solution to form a homogeneous suspension. 6 μL of the suspension was dropped onto an L-shaped glassy carbon electrode (d = 5 mm) and dried at room temperature to prepare the working electrode. The counter electrode was a carbon rod, and the reference electrode was a saturated calomel electrode (SCE). The electrolyte was a 1 M NaNO3 and a 0.4 M Ni(NO3)2 aqueous solution. These were arranged into a three-electrode system, and electrochemical performance tests were conducted on an electrochemical workstation and a battery testing system. The electrochemical performance test results of NiFeHCF, NiFeHCF-2, and NiFeHCF-3 are as follows: Figure 3 As shown.

[0035] Cyclic voltammetry results showed that NiFeHCF exhibited three sets of redox peaks at 0.424 V / 0.438 V, 0.548 V / 0.559 V, and 0.705 V / 0.729 V, while NiFeHCF-2 and NiFeHCF-3 showed a pair of redox peaks at 0.434 V / 0.415 V and 0.462 V / 0.445 V, respectively. Figure 3 a). These peaks indicate Fe.2+ / Fe 3+ The redox reaction indicates that the insertion and extraction of sodium ions from the NiFeHCF framework is reversible. Constant current charge-discharge test results show that at 0.1 A g... −1 At the given current density, the initial discharge specific capacities of NiFeHCF, NiFeHCF-2, and NiFeHCF-3 were 87.98 mAh g⁻¹. −1 25.08 mAh g −1 and 39.81 mAh g −1 ( Figure 3 b). At a high current density of 3.0 A g −1 Under these conditions, the discharge specific capacity of NiFeHCF reached 58.66 mAh g. −1 ( Figure 3 c). Figure 3 d is the Nyquist plot of NiFeHCF, which includes two insets: the upper right inset is the equivalent circuit diagram (EEC) obtained by ZView software simulation, and the lower right inset is a magnified view of the high-frequency region, with the charge transfer resistance of 3.38 Ω obtained by ZView software simulation.

[0036] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing nickel-based Prussian blue analog nanoparticles, comprising: Under the action of ethylenediaminetetraacetic acid salt and polyvinylpyrrolidone, water-soluble nickel salt reacts thermally with water-soluble ferrous cyanide salt or ferric cyanide salt to obtain the nickel-based Prussian blue analog nanoparticles.

2. The preparation method according to claim 1, characterized in that: The water-soluble nickel salt is nickel chloride and / or nickel nitrate.

3. The preparation method according to claim 1, characterized in that: The ethylenediaminetetraacetic acid salt includes at least one of ethylenediaminetetraacetic acid dilithium salt, ethylenediaminetetraacetic acid tetralithium salt, ethylenediaminetetraacetic acid disodium salt, ethylenediaminetetraacetic acid tetrasodium salt, ethylenediaminetetraacetic acid dipotassium salt, and ethylenediaminetetraacetic acid tetrapotassium salt.

4. The preparation method according to claim 3, characterized in that: The molar ratio of the ethylenediaminetetraacetic acid salt to the water-soluble nickel salt is 1~5:

1.

5. The preparation method according to claim 4, characterized in that: The molar ratio of the ethylenediaminetetraacetic acid salt to the water-soluble nickel salt is 1~1.2:

1.

6. The preparation method according to claim 1, characterized in that: The water-soluble ferrocyanide salt is sodium ferrocyanide and / or potassium ferrocyanide, and the water-soluble ferrocyanide salt is potassium ferrocyanide.

7. The preparation method according to claim 6, characterized in that: The molar ratio of the water-soluble ferrocyanide or ferrocyanide to the water-soluble nickel salt is 1:

1.

8. The preparation method according to claim 1, characterized in that: The K value of the polyvinylpyrrolidone is 27~30.

9. The preparation method according to claim 8, characterized in that: The mass ratio of polyvinylpyrrolidone to water-soluble nickel salt is 1~3:

1.

10. The preparation method according to claim 9, characterized in that: The mass ratio of polyvinylpyrrolidone to water-soluble nickel salt is 1.3~1.5:

1.

11. The preparation method according to claim 1, characterized in that: In the reaction system, the initial concentration of the water-soluble nickel salt is 0.01~0.2 mol / L.

12. The preparation method according to claim 1, characterized in that: The hydrothermal reaction is carried out at a temperature of 80~180 ℃ for a time of 12~72 h.

13. Nickel-based Prussian blue analog nanoparticles prepared by the method according to any one of claims 1-12.

14. The nickel-based Prussian blue analog nanoparticles according to claim 13, characterized in that: The particle size of the nickel-based Prussian blue analog nanoparticles is no greater than 50 nm.

15. The application of the nickel-based Prussian blue analog nanoparticles according to claim 13 in the preparation of the positive electrode of an aqueous sodium-ion battery.

Images