Nickel-based prussian blue battery positive electrode material, preparation method thereof and battery

Abstract

The application discloses a nickel-based Prussian blue battery positive electrode material and a preparation method and battery thereof, and belongs to the technical field of batteries, wherein the preparation method of the nickel-based Prussian blue battery positive electrode material comprises the following steps: dissolving sodium citrate into a nickel chloride solution to obtain reagent A; dissolving sodium ferrocyanide in water to prepare a solution to obtain reagent B; dissolving polyvinylpyrrolidone in a sodium chloride solution to obtain reagent C; simultaneously and slowly adding the reagent A and the reagent B into the reagent C to obtain a suspension liquid and aging the suspension liquid; centrifugally separating the suspension liquid after aging, washing, drying and grinding to obtain the nickel-based Prussian blue battery positive electrode material; and the nickel-based Prussian blue battery positive electrode material prepared by the application has the characteristics of high capacity, low alternating current impedance and high long cycle stability, and has excellent electrochemical performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a nickel-based Prussian blue battery positive electrode material, a preparation method thereof and a battery. BACKGROUND

[0002] Due to the depletion of traditional fossil energy and environmental problems caused by its use, humans urgently need to research and develop new clean energy to support daily life and production needs and promote the sustainable development of social energy. Lithium ion batteries are widely used in the energy storage field, but lithium resources are limited and unevenly distributed, and the mining difficulty is gradually increasing. Sodium ion batteries are considered as an ideal alternative system for lithium ion batteries because of abundant resources and low cost, and have great potential in large-scale energy storage.

[0003] As a highly potential energy source, sodium ion batteries have received extensive attention from academia and industry in recent years. With the continuous breakthroughs in material science, especially the development of new positive and negative electrode materials, the performance of sodium ion batteries has been significantly improved, and they have become a research hotspot again.

[0004] Nowadays, sodium ion batteries have been preliminarily applied in low-speed electric vehicles, energy storage systems and other fields, showing good development potential. However, there is still a certain gap between sodium ion batteries and lithium ion batteries in terms of energy density, cycle life and other performance, and sodium ion batteries still face many challenges in the optimization of electrode materials, the improvement of battery manufacturing process and the integration of battery systems, which need further research and technological breakthroughs. SUMMARY

[0005] An object of the present application is to solve at least the above problems and / or drawbacks, and to provide at least the advantages stated hereinafter.

[0006] To achieve these objects and other advantages of the present application, a preparation method of a nickel-based Prussian blue battery positive electrode material is provided, comprising the following steps:

[0007] Step one, dissolve sodium citrate into a nickel chloride solution to obtain reagent A, dissolve sodium ferrocyanide in water to prepare a solution to obtain reagent B, and dissolve polyvinylpyrrolidone (PVP) in a sodium chloride solution to obtain reagent C;

[0008] Step two, simultaneously and slowly add reagent A and reagent B to reagent C at room temperature, and continuously stir reagent C until reagent A and reagent B are completely added to reagent C, to obtain a suspension, and age the obtained suspension;

[0009] Step three, centrifuge the suspension after aging, wash the obtained precipitate with deionized water and ethanol, and then dry and grind to obtain a nickel-based Prussian blue battery positive electrode material.

[0010] Preferably, in the step one, the amount ratio of sodium citrate to nickel chloride solution is 4.4-8.8 g:25-50 mL, the concentration of nickel chloride solution is 0.1-0.2 mol / L, the concentration of sodium ferrocyanide solution is 0.1-0.2 mol / L, the amount ratio of polyvinylpyrrolidone to sodium chloride solution is 8 g:100-200 mL, and the concentration of sodium chloride solution is 0.25-0.5 mol / L.

[0011] Preferably, in the step two, the amount ratio of reagent A, reagent B and reagent C is 12.5-25 mL:25 mL:100 mL, the dropping time is 1-2 h, and the aging time of the suspension is 8-10 h.

[0012] Preferably, in the step three, the washing is performed for 3-5 times with deionized water and ethanol respectively, and the drying condition is vacuum drying at 70-80 ℃ for 24-36 h; the grinding is performed for 0.5-1 h by using a mortar.

[0013] Preferably, the nickel-based Prussian blue battery positive electrode material prepared in the step three is subjected to post-treatment modification, and the method is as follows:

[0014] S31, dispersing the nickel-based Prussian blue battery positive electrode material powder into water, adding manganese chloride, adding potassium permanganate into the solution after the manganese chloride is completely dissolved, heating the solution in a water bath for a period of time, then performing suction filtration, and washing the obtained solid to obtain the treated nickel-based Prussian blue battery positive electrode material;

[0015] S32, dispersing the treated nickel-based Prussian blue battery positive electrode material into water again, then adding trichloroacetic acid and pyrrole, stirring for a period of time, performing suction filtration, washing and drying to obtain the modified nickel-based Prussian blue battery positive electrode material.

[0016] Preferably, in the S31, the amount ratio of the nickel-based Prussian blue battery positive electrode material powder, manganese chloride, potassium permanganate and water is 10-20 g:2-2.5 g:1 g:100-150 mL.

[0017] Preferably, in the S31, the water bath heating temperature is 85-90 ℃, and the heating time is 1-2 h.

[0018] Preferably, in the S32, the amount ratio of the treated nickel-based Prussian blue battery positive electrode material, trichloroacetic acid, pyrrole and water is 10 g:0.01-0.02 mol:0.03-0.05 mol:100-200 mL, and the stirring time is 12-24 h.

[0019] A nickel-based Prussian blue battery positive electrode material is prepared by the above-mentioned method for preparing a nickel-based Prussian blue battery positive electrode material.

[0020] A battery, wherein the positive electrode material is the nickel-based Prussian blue battery positive electrode material.

[0021] The nickel-based Prussian blue battery positive electrode material prepared by the method has the advantages that when the nickel-based Prussian blue battery positive electrode material is used as a positive electrode material of a sodium ion battery, the nickel-based Prussian blue battery positive electrode material has the characteristics of high capacity, low alternating current impedance and high long cycle stability, and has excellent electrochemical performance; in addition, the nickel-based Prussian blue battery positive electrode material is modified, manganese oxide is generated by oxidizing manganese chloride with potassium permanganate, the manganese oxide is loaded on the surface of the nickel-based Prussian blue battery positive electrode material, polypyrrole is coated on the nickel-based Prussian blue battery positive electrode material loaded with the manganese oxide in trichloroacetic acid, and the trichloroacetic acid removes possible crystal water in the nickel-based Prussian blue battery positive electrode material in the reaction process; the loaded manganese oxide and the coated polypyrrole both have good conductivity, and the conductivity of the nickel-based Prussian blue battery positive electrode material can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 SEM image of the material prepared in Example 1;

[0023] Figure 2 SEM image of the material prepared in Example 2;

[0024] Figure 3 SEM image of the material prepared in Comparative Example 1;

[0025] Figure 4 SEM image of the material prepared in Comparative Example 2;

[0026] Figure 5 XRD spectrum of the material prepared in Example 1;

[0027] Figure 6 CV diagram of the materials prepared in Examples 1-2 and Comparative Examples 1-2;

[0028] Figure 7 Variation diagram of specific capacity of the materials prepared in Examples 1-2 and Comparative Examples 1-2 at different rates;

[0029] Figure 8 Variation diagram of specific capacity of the materials prepared in Examples 3-5 and Example 1 at different rates;

[0030] Figure 9 Charging and discharging curve diagram of the battery prepared by using the material prepared in Example 1 and subjected to cycle test at 2C;

[0031] Figure 10 Charging and discharging curve diagram of the battery prepared by using the material prepared in Example 2 and subjected to cycle test at 2C;

[0032] Figure 11A long cycle test graph for the material prepared in Example 1 was prepared into a battery at 2C;

[0033] Figure 12 A long cycle test graph for the material prepared in Example 2 was prepared into a battery at 2C. DETAILED DESCRIPTION

[0034] The application will be further described in conjunction with the embodiments and drawings, so that those skilled in the art can implement the application according to the description.

[0035] Example 1

[0036] A preparation method of a nickel-based Prussian blue battery positive electrode material, comprising the following steps:

[0037] Step one, 8.8g of sodium citrate is dissolved into a 25mL nickel chloride solution with a concentration of 0.2mol / L to obtain reagent A, 0.02mol of sodium ferrocyanide is dissolved in 100mL of water to prepare a solution with a concentration of 0.2mol / L to obtain reagent B, and 8g of polyvinylpyrrolidone PVP (K30) is dissolved in 100mL of a sodium chloride solution with a concentration of 0.5mol / L to obtain reagent C;

[0038] Step two, 25mL of reagent A and 25mL of reagent B are simultaneously and slowly added to 100mL of reagent C at room temperature, the dropping time is 1h, and the reagent C is continuously stirred until the reagent A and the reagent B are completely added to the reagent C, to obtain a suspension, and the obtained suspension is aged for 8h;

[0039] Step three, the suspension after aging is centrifuged to obtain a precipitate, which is washed with deionized water and ethanol for 3 times respectively, and then vacuum dried at 70℃ for 24h, the dried powder is fully ground in a mortar for 0.5h to obtain a nickel-based Prussian blue battery positive electrode material, which is recorded as NiHCF-3.2%.

[0040] Example 2

[0041] The difference between this example and Example 1 is that the amount of sodium citrate in Step one is 4.4g, and the other steps are consistent with Example 1, to obtain a nickel-based Prussian blue battery positive electrode material, which is recorded as NiHCF-1.6%.

[0042] Example 3

[0043] The steps one to three of this example are consistent with Example 1, and the difference is that the nickel-based Prussian blue battery positive electrode material prepared in Step three is modified by post-treatment, and the method is:

[0044] S31, 10 g of nickel-based Prussian blue battery positive material powder was dispersed into 100 mL of water, then 2 g of manganese chloride was added, after the manganese chloride was completely dissolved, 1 g of potassium permanganate was added to the solution, heated under water bath at 85℃ for 2 h, then filtered, washed the obtained solid, to obtain the treated nickel-based Prussian blue battery positive material, recorded as M-NiHCF-3.2%.

[0045] S32, 10 g of the treated nickel-based Prussian blue battery positive material was dispersed into 100 mL of water, then 1.63 g of trichloroacetic acid and 2.01 g of pyrrole were added, stirred for 12 h, filtered, washed, and dried to obtain the modified nickel-based Prussian blue battery positive material, recorded as G-NiHCF-3.2%.

[0046] Example 4

[0047] The steps one to three of this example are consistent with example 1, the difference is that the nickel-based Prussian blue battery positive material prepared in step three is modified by post-treatment, the method is:

[0048] S31, 10 g of nickel-based Prussian blue battery positive material powder was dispersed into 100 mL of water, then 2 g of manganese chloride was added, after the manganese chloride was completely dissolved, 1 g of potassium permanganate was added to the solution, heated under water bath at 85℃ for 2 h, then filtered, washed the obtained solid, to obtain the treated nickel-based Prussian blue battery positive material, recorded as M-NiHCF-3.2%.

[0049] Example 5

[0050] The steps one to three of this example are consistent with example 1, the difference is that the nickel-based Prussian blue battery positive material prepared in step three is modified by post-treatment, the method is:

[0051] S31, 10 g of nickel-based Prussian blue battery positive material powder was dispersed into 100 mL of water, then 2 g of manganese chloride was added, after the manganese chloride was completely dissolved, 1 g of potassium permanganate was added to the solution, heated under water bath at 85℃ for 2 h, then filtered, washed the obtained solid, to obtain the treated nickel-based Prussian blue battery positive material, recorded as M-NiHCF-3.2%.

[0052] Comparative Example 1

[0053] Step one, 8.8 g of sodium citrate was dissolved into 25 mL of 0.2 mol / L FeSO4 solution to obtain reagent A, 0.02 mol of sodium ferrocyanide was dissolved in 100 mL of water to prepare a 0.2 mol / L solution to obtain reagent B, 8 g of polyvinylpyrrolidone PVP (K30) was dissolved in 100 mL of 0.5 mol / L sodium chloride solution to obtain reagent C;

[0054] Step 2: At room temperature, add 25 mL of reagent A and 25 mL of reagent B simultaneously and slowly to 100 mL of reagent C over a period of 1 hour, while continuously stirring reagent C until all reagent A and reagent B have been added to reagent C to obtain a suspension. Then, age the suspension for 8 hours.

[0055] Step 3: Centrifuge the aged suspension to separate the precipitate. Wash the precipitate three times with deionized water and ethanol, respectively. Then, vacuum dry it at 70°C for 24 hours. Grind the dried powder thoroughly in a mortar for 0.5 hours. The resulting battery cathode material is denoted as NiHCF-Fe.

[0056] Comparative Example 2

[0057] The difference between this comparative example and Example 1 is that, in step one, when preparing reagent C, polyvinylpyrrolidone (PVP) (K30) is not added, and a 0.5 mol / L sodium chloride solution is used directly; the other steps are the same as in Example 1, and the resulting battery cathode material is denoted as NiHCF-PVP-free.

[0058] The materials prepared in Examples 1-2 and Comparative Examples 1-2 were subjected to electron microscopy, and the resulting SEM images (scale bar length 2 μm) are shown below. Figures 1-4 As shown, where, Figure 1 The image shows the SEM image of the material prepared in Example 1. Figure 2 This is a SEM image of the material obtained in Example 2. Figure 3 The image shows the SEM image of the material prepared in Comparative Example 1. Figure 4 To obtain the SEM image of the material prepared in Comparative Example 2, from Figures 1-4 It can be seen that the NiHCF-3.2% and NiHCF-1.6% prepared in the examples have rough surfaces and porous structures. This porous structure increases the specific surface area of ​​the material, which is beneficial to the surface reaction process. In contrast, the NiHCF-Fe prepared in Comparative Example 1 has more uniform size and exhibits an approximately cubic structure. The NiHCF-PVP-free particles prepared in Comparative Example 2 are all smaller and may have a wider size distribution. The particle size and distribution will affect the material's reactivity and mass transfer process.

[0059] Figure 5The XRD pattern of the material prepared in Example 1 was obtained; it can be seen that the diffraction peaks of NiHCF-3.2% are split into two peaks with similar intensity at 24.5°, 34.5° and 47.8°, indicating that they are all rhombic face structure, and the peaks at (200), (420), (440), (620) and the like are split, changing from single peak to double peak, and the rhombohedral phase is obtained according to the splitting phenomenon, and the peaks at (111), (202), (404) and the like conform to the standard, indicating that the NiHCF-3.2% material has the expected crystal structure characteristics; the (202) and (404) peaks have high intensity, indicating that the corresponding crystal faces are more prominent in the NiHCF-3.2% material; according to the diffraction peak position and intensity, combined with the standard card, it can be determined that the main phase in the material is the target NiHCF-3.2% phase.

[0060] The nickel-based Prussian blue battery positive electrode material prepared in Example 1 was made into an electrode sheet, and the electrode sheet, an electrode shell, four drops of electrolyte and a 16 mm diameter glass were assembled into a CR2025 type button cell, and the battery was subjected to electrochemical performance test; wherein the electrode sheet preparation method is as follows:

[0061] S1, 5g PVDF was dispersed in 95g NMP to prepare a 5wt% PVDF solution as a binder;

[0062] S2, 8g of the nickel-based Prussian blue battery positive electrode material powder prepared in Example 1, 1g of conductive carbon black (SuperP) and 1g of the binder were mixed, NMP solvent was added dropwise to adjust the viscosity, and the slurry was obtained after stirring;

[0063] S3, the slurry was coated on a cleaned aluminum foil using a coater, and the aluminum foil was dried at 120°C under vacuum conditions for 12h, and then cut into a circular electrode sheet with a diameter of 14mm.

[0064] The nickel-based Prussian blue battery positive electrode materials prepared in Examples 2-5 and the battery positive electrode materials prepared in Comparative Examples 1-2 were also made into electrode sheets and assembled into button cells according to the above method, and electrochemical performance test was carried out.

[0065] Figure 6CV plots of the materials prepared in Example 1-2 and Comparative Example 1-2; from the figure, it can be seen that the redox peaks of NiHCF-1.6% and NiHCF-3.2% are more obvious, the oxidation peak potential of NiHCF is 3.399 V, the reduction peak potential is 3.045 V, and the potential difference between the two peaks is 354 mV; the oxidation peak potential of NiHCF-3.2% is 3.569 V, the reduction peak potential is -3.29 V, and the potential difference between the two peaks is 278 mV; the peak potential difference of NiHCF-3.2% is obviously smaller than that of NiHCF-1.6%, indicating that the polarization degree of NiHCF-3.2% is small, and it has better kinetic performance; the area surrounded by the curve and the potential axis represents the charge transfer, compared with NiHCF-1.6%, NiHCF-Fe and NiHCF-PVP-free, the area of NiHCF-3.2% is larger, indicating that the amount of charge transferred during the redox reaction in this potential range is more.

[0066] Figure 7 The specific capacity change graph of the materials prepared in Example 1-2 and Comparative Example 1-2 at different rates; from the figure, it can be seen that when the rate of the four materials increases from 0.1 C to 3 C, the specific capacity value gradually decreases, NiHCF-PVP-free decreases from 23.22 mAh / g to 10.72 mAh / g, NiHCF-Fe decreases from 28.60 mAh / g to 17.19 mAh / g, NiHCF-1.6% decreases from 58.22 mAh / g to 32.72 mAh / g, and NiHCF-3.2% decreases from 65.60 mAh / g to 36.19 mAh / g. At a low rate of 0.1 C, NiHCF-1.6% and NiHCF-3.2% have relatively high specific capacity, but at a high rate of 3 C, the specific capacity decreases significantly, because at a high rate, the polarization effect inside the battery is enhanced, and the ion diffusion and charge transfer process is limited. By comparing the specific capacity performance of the four materials at the same rate, it can be seen that the specific capacity of NiHCF-3.2% is the highest, indicating that the material NiHCF-3.2% has better electrochemical performance at the same rate.

[0067] Figure 8The specific capacity of the materials prepared in Examples 3-5 and Example 1 at different rates is shown in the graph. As can be seen from the graph, Example 3 is a post-treatment modification of the prepared nickel-based Prussian blue battery positive electrode material. First, manganese chloride is generated by potassium permanganate oxidation, and Mn304 is loaded on the surface of the nickel-based Prussian blue battery positive electrode material. Then, polypyrrole is coated on the nickel-based Prussian blue battery positive electrode material loaded with Mn304 in trichloroacetic acid, and trichloroacetic acid is used to remove the crystal water that may exist in the nickel-based Prussian blue battery positive electrode material during the reaction. The loaded Mn304 and the coated polypyrrole both have good conductivity, which can improve the conductivity of the nickel-based Prussian blue battery positive electrode material. When the rate increases from 0.1C to 3C, the specific capacity of G-NiHCF-3.2% decreases from 72.42 mAh / g to 41.21 mAh / g, and the specific capacity at different rates is improved. In Example 4, only Mn304 is loaded on the nickel-based Prussian blue to obtain M-NiHCF-3.2% material. When the rate increases from 0.1C to 3C, the specific capacity decreases from 68.34 mAh / g to 37.15 mAh / g. Although the specific capacity is also improved, it is not as good as Example 3. In Example 5, polypyrrole is coated on the nickel-based Prussian blue to obtain B-NiHCF-3.2% material. When the rate increases from 0.1C to 3C, the specific capacity decreases from 70.12 mAh / g to 38.28 mAh / g. Although the specific capacity is also improved, it is not as good as Example 3.

[0068] Figures 9-10 The materials prepared in Example 1 and Example 2 were prepared into batteries and tested for charge-discharge curves at 2C (1C = 75 mAhg -1 ) under cyclic conditions. Among them Figure 9 corresponding to Example 1, Figure 10 corresponding to Example 2, the first discharge capacity of NiHCF-3.2% is 58.43 mAh / g, and the 30th discharge capacity is 51.66 mAh / g, so the capacity retention rate is 88.42%; the first discharge capacity of NiHCF-1.6% is 58.00 mAh / g, and the 30th discharge capacity is 50.01 mAh / g, so the capacity retention rate is 86.23%. As can be seen, the potential platform of NiHCF-3.2% is more stable, and the decay is slower, indicating that the structure is more stable, and the cycle performance of NiHCF-3.2% is better, showing better cycle stability.

[0069] Figures 11-12 The materials prepared in Example 1 and Example 2 were prepared into batteries and tested for long cycle at 2C. Among them Figure 11 corresponding to Example 1, Figure 12Corresponding to Example 2, at 2C rate, the initial charge capacity of NiHCF-1.6% is higher than that of NiHCF-3.2%, indicating that NiHCF-1.6% has higher energy storage capacity at the initial stage, the capacity attenuation curve of NiHCF-3.2% material is relatively flat, and it performs more stable in long cycle, while the NiHCF-1.6% material has high initial capacity, but the attenuation amplitude is larger, and the stability is slightly poor; the attenuation of NiHCF-3.2% material is slower, and the stability is better, the specific capacity attenuation is slower and the efficiency is higher, and it performs better long cycle stability and higher efficiency at 2C rate.

[0070] While the embodiments of the application have been disclosed as above, it is not limited to the use listed in the specification and embodiments, and can be fully applied to various fields suitable for the application, and additional modifications can be easily realized by those skilled in the art, and therefore the application is not limited to specific details and the figures shown and described herein.

Claims

1. A method for preparing a nickel-based Prussian blue battery cathode material, characterized in that, Includes the following steps: Step 1: Dissolve sodium citrate in nickel chloride solution to obtain reagent A; dissolve sodium ferrocyanide in water to prepare a solution to obtain reagent B; dissolve polyvinylpyrrolidone in sodium chloride solution to obtain reagent C. Step 2: At room temperature, add reagent A and reagent B simultaneously and slowly dropwise to reagent C while continuously stirring reagent C until all reagent A and reagent B have been added to reagent C, thus obtaining a suspension. Then, age the obtained suspension. Step 3: Centrifuge the aged suspension to separate the precipitate. Wash the precipitate with deionized water and ethanol, then dry and grind it to obtain the nickel-based Prussian blue battery cathode material. The prepared nickel-based Prussian blue material is then post-treated and modified using the following method: S31. Disperse the nickel-based Prussian blue battery cathode material powder in water, then add manganese chloride. After the manganese chloride is completely dissolved, add potassium permanganate to the solution, heat in a water bath for a period of time, then filter and wash the obtained solid to obtain the treated nickel-based Prussian blue battery cathode material. S32. The treated nickel-based Prussian blue battery cathode material is dispersed again in water, then trichloroacetic acid and pyrrole are added, the mixture is stirred and reacted for a period of time, filtered, washed and dried to obtain the modified nickel-based Prussian blue battery cathode material. In step S31, the ratio of nickel-based Prussian blue battery cathode material powder, manganese chloride, potassium permanganate, and water is 10~20g:2~2.5g:1g:100~150mL; the water bath heating temperature is 85~90℃, and the heating time is 1~2h. In step S32, the ratio of the treated nickel-based Prussian blue battery cathode material, trichloroacetic acid, pyrrole, and water is 10g:0.01~0.02mol:0.03~0.05mol:100~200mL, and the reaction is stirred for 12~24h.

2. The method for preparing the nickel-based Prussian blue battery cathode material as described in claim 1, characterized in that, In step one, the ratio of sodium citrate to nickel chloride solution is 4.4~8.8g:25~50mL, the concentration of nickel chloride solution is 0.1~0.2mol / L, the concentration of sodium ferrocyanide solution is 0.1~0.2mol / L, the ratio of polyvinylpyrrolidone to sodium chloride solution is 8g:100~200mL, and the concentration of sodium chloride solution is 0.25~0.5mol / L.

3. The method for preparing the nickel-based Prussian blue battery cathode material as described in claim 1, characterized in that, In step two, the ratio of reagent A, reagent B and reagent C is 12.5~25mL:25mL:100mL, the dropping time is 1~2h, and the aging time of the suspension is 8~10h.

4. The method for preparing the nickel-based Prussian blue battery cathode material as described in claim 1, characterized in that, In step three, the washing process involves washing with deionized water and ethanol 3 to 5 times each, and drying under vacuum at 70 to 80°C for 24 to 36 hours. The grinding process involves grinding in a mortar and pestle for 0.5 to 1 hour.

5. A nickel-based Prussian blue battery cathode material, characterized in that, It is prepared by the method for preparing nickel-based Prussian blue battery cathode material according to any one of claims 1-4.

6. A battery, characterized in that, The positive electrode material of the battery is the nickel-based Prussian blue battery positive electrode material as described in claim 5.

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