Iron-manganese-based sodium ion battery positive electrode material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of sodium-ion batteries, and particularly relates to an iron-manganese-based sodium-ion battery positive electrode material as well as a preparation method and application thereof. The preparation method of the iron-manganese-based sodium ion battery positive electrode material comprises the following steps: adding ferric nitrate and manganese nitrate into water for dissolving, performing spray pyrolysis to obtain an iron-manganese oxide precursor, performing ball-milling mixing on sodium carbonate, the iron-manganese oxide precursor and lanthanum telluride, and calcining in an inert gas atmosphere to obtain a composite material; and adding Ni4O4 cubic alkane modified carbazole, the composite material and manganese dioxide into dilute sulphuric acid for ultrasonic dispersion, stirring for reaction, centrifuging, washing and drying to obtain the iron-manganese-based sodium ion positive electrode material. The iron-manganese-based sodium ion battery positive electrode material provided by the invention has the advantages of stable rate cycle, high specific capacity and excellent capacity retention rate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sodium ion batteries, and particularly relates to an iron-manganese-based sodium ion battery positive electrode material and a preparation method and application thereof. BACKGROUND

[0002] With the gradual depletion of chemical energy and the environmental pollution problems caused by the use of chemical energy, developing new renewable energy has become a general trend, and energy storage technology, as an important part of power generation and power systems, has also become a technical barrier that needs to be overcome. Electrochemical energy storage technology has the advantages of fast response speed, short construction period, high conversion efficiency and flexible configuration, and has developed rapidly in recent years. Among them, lithium batteries are widely used in mobile portable devices and electric vehicles due to their high energy density, long cycle life and green environmental protection. However, the current lithium resources are scarce, and it is difficult to extract, and the recycling industry has not yet formed a scale. In recent years, the price of lithium has risen rapidly, which has seriously hindered market development, so the development of alternative products is imminent.

[0003] Sodium and lithium are homologous elements, and sodium ion batteries have similar charging and discharging principles and working mechanisms as lithium ion batteries. Although the energy density is slightly lower than that of lithium ion batteries, the low-temperature performance and rate performance are better than those of lithium ion batteries, and the sodium reserves are 1000 times that of lithium, so it is considered as the most potential substitute for lithium ion batteries. Sodium ion battery positive electrode materials mainly include transition metal oxides, polyanion compounds, prussian blue analogues and organic compounds, etc. Among them, iron-manganese-based transition metal oxides have the advantages of low price, environmental friendliness and high energy density, and have good application potential in sustainable and environmentally friendly batteries. However, they have problems such as poor structural stability and air sensitivity, which can easily cause battery failure during the cycle process. Using methods such as doping, surface modification and composite structure design to improve the cycle performance and further increase the capacity is the research direction to meet the practical application of sodium ion batteries. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the first purpose of the present application is to provide a preparation method of an iron-manganese-based sodium ion battery positive electrode material.

[0005] The second purpose of the present application is to provide an iron-manganese-based sodium ion battery positive electrode material obtained by the above preparation method.

[0006] The third purpose of the present application is to provide an application of the above iron-manganese-based sodium ion battery positive electrode material. The iron-manganese-based sodium ion battery positive electrode material of the present application has the advantages of rate cycle stability, high specific capacity and excellent capacity retention rate when applied to sodium ion battery positive electrodes.

[0007] In order to achieve the above purposes, the technical scheme adopted by the present application is: A preparation method of an iron-manganese-based sodium-ion battery positive electrode material, comprising the following steps: (1) Dissolve ferric nitrate and manganese nitrate in water, spray pyrolysis to obtain an iron-manganese oxide precursor; then ball mill sodium carbonate, the iron-manganese oxide precursor and lanthanum telluride, and calcine under an inert gas atmosphere to obtain a composite material; (2) Add Ni4O4 cubic alkane modified carbazole, the composite material and manganese dioxide into dilute sulfuric acid, ultrasonically disperse, react under stirring, centrifuge, wash, dry to obtain the iron-manganese-based sodium-ion positive electrode material.

[0008] Further, in step (1), the molar ratio of the ferric nitrate, manganese nitrate, sodium carbonate and lanthanum telluride is 1:(0.8-1.2):(0.8-1):(0.1-0.4).

[0009] Further, in step (1), the temperature of the spray pyrolysis is 500-700 DEG C, the flow rate of the carrier gas stream is 8-12 L / min; the carrier gas stream is air, and the residence time of the carrier gas stream is 20-40 s; the temperature of the calcination is 800-950 DEG C, and the time is 10-15 h.

[0010] Further, in step (2), the mass ratio of the Ni4O4 cubic alkane modified carbazole, manganese dioxide and composite material is 10:(4-5):(0.5-1); the concentration of the dilute sulfuric acid is 4 mol / L; and the reaction time is 15-20 h.

[0011] Further, in step (2), the Ni4O4 cubic alkane modified carbazole is prepared by the following preparation process: (a) Add nickel chloride, salicylaldehyde and triethylamine into methanol, stir until no more precipitate is precipitated, filter, wash, dry to obtain Ni4O4 cubic alkane; (b) Add the Ni4O4 cubic alkane, 3-bromocarbazole, tetrabutylammonium bromide and sodium hydroxide solution into toluene, reflux to obtain the Ni4O4 cubic alkane modified carbazole.

[0012] Further, in step (a), the molar ratio of the nickel chloride, salicylaldehyde and triethylamine is 1:(0.8-1.2):(1.5-1.7).

[0013] Further, in step (b), the amount ratio of the Ni4O4 cubic alkane, 3-bromocarbazole, tetrabutylammonium bromide and sodium hydroxide solution is 1 g:(1-2) g:0.1 g:2 mL; the concentration of the sodium hydroxide solution is 0.02-0.05 mol / L; the reflux reaction temperature is 60-80 DEG C, and the time is 8-12 h.

[0014] The iron-manganese-based sodium-ion battery positive electrode material is prepared by the preparation method of the iron-manganese-based sodium-ion battery positive electrode material.

[0015] The iron-manganese-based sodium-ion battery positive electrode material is applied to a sodium-ion battery.

[0016] The iron-manganese-based sodium-ion battery positive electrode material is applied to a sodium-ion battery. 1. The iron-manganese-based transition metal oxide positive electrode material is modified by doping lanthanum telluride, which has excellent electronic conductivity, and can form a good electron channel in the iron-manganese-based oxide, improving the problem of poor conductivity, and the lanthanum ion has a large ionic radius, which can increase the interlayer spacing of the material and reduce the diffusion resistance of sodium ions, improve the electronic transmission efficiency of the positive electrode material, and improve the rate performance and reversible capacity of the material; at the same time, the lanthanum ion can stabilize the electronic configuration of the manganese ion, reduce the Jahn-Teller distortion in the charging and discharging process, and cooperates with the tellurium ion to effectively enhance the structure and interface stability of the positive electrode material and improve the cycle stability.

[0017] 2. The Ni4O4 cubic alkane modified carbazole is coated on the surface of the composite material as a protective layer, the carbazole unit has a large pi conjugated plane, showing good conductivity and flexibility, which can effectively isolate the electrolyte from the iron-manganese-based oxide and prevent the electrolyte from corroding and damaging the iron-manganese-based oxide, and inhibit the volume change caused by the sodium ion extraction and embedding in the cycle process, and improve the cycle stability of the positive electrode material. The Ni4O4 cubic alkane has a cubic symmetry structure and good chemical stability, and the modified carbazole using the Ni4O4 cubic alkane can further enhance the structural stability of the coating layer; and the Ni4O4 cubic alkane has a metal-like conductivity, which can cooperatively construct a stable and conductive interface layer with the carbazole unit, which can not only isolate the electrolyte corrosion, but also optimize the electron transmission path, thereby comprehensively improving the specific capacity and rate performance of the positive electrode material. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The infrared spectrum of the Ni4O4 cubic alkane modified carbazole prepared in Preparation Example 1 is shown in the figure; Figure 2 The scanning electron microscope image of the iron-manganese-based sodium-ion battery positive electrode material prepared in Example 1 is shown in the figure; Figure 3 The scanning electron microscope image of the iron-manganese-based sodium-ion battery positive electrode material prepared in Example 1 is shown in the figure. DETAILED DESCRIPTION

[0019] The following further describes the present application in connection with specific preferred embodiments, which should not be construed as limiting the present application to the specific embodiments. Those skilled in the art of the present application can make several simple deductions or substitutions without departing from the concept of the present application, which should be considered as falling within the scope of the present application. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturers. The reagents or instruments used are conventional products obtained from the market, unless otherwise specified.

[0020] (I) Preparation Example Preparation Example 1 Preparation Example 1 provides a Ni4O4 cubane modified carbazole prepared by the following preparation method: (a) According to the amount ratio of nickel chloride, salicylaldehyde, triethylamine and methanol 1 mol: 1 mol: 1.6 mol: 1 L, nickel chloride, salicylaldehyde and triethylamine are added to methanol and stirred until the precipitate no longer precipitates, and the precipitate is filtered out, washed and dried to obtain Ni4O4 cubane; (b) According to the amount ratio of Ni4O4 cubane, 3-bromocarbazole, tetrabutylammonium bromide, sodium hydroxide solution and toluene 1 g: 1.5 g: 0.1 g: 2 mL: 50 mL, Ni4O4 cubane, 3-bromocarbazole, tetrabutylammonium bromide and 0.03 mol / L sodium hydroxide solution are added to toluene to obtain a mixed solution, and the mixed solution is refluxed at 70°C for 10h to obtain Ni4O4 cubane modified carbazole.

[0021] The infrared spectrum of the Ni4O4 cubane modified carbazole prepared in this preparation example is shown in Figure 1 The -O-H absorption peak in the ligand appears near 3500 cm -1 , the -N-H absorption peak of 3-bromocarbazole appears near 3400 cm -1 , and the C-Br stretching vibration peak appears at 500-700 cm -1 . In the Ni4O4 cubane modified carbazole generated after the reaction of Ni4O4 cubane and 3-bromocarbazole, the -O-H absorption peak near 3500 cm -1 is significantly weakened, and the C-Br stretching vibration peak at 500-700 cm -1 disappears, proving the successful synthesis of Ni4O4 cubane modified carbazole.

[0022] Preparation Example 2 Preparation Example 2 provides a Ni4O4 cubane modified carbazole prepared by the following preparation method: (a) According to the amount ratio of nickel chloride, salicylaldehyde, triethylamine and formaldehyde 1 mol: 0.8 mol: 1.5 mol: 1 L, the nickel chloride, salicylaldehyde and triethylamine are added into the formaldehyde to stir until the precipitation no longer precipitates, the precipitate is filtered out, washed and dried to obtain Ni4O4 cubane; (b) According to the amount ratio of Ni4O4 cubane, 3-bromocarbazole, tetrabutylammonium bromide, 0.02 mol / L sodium hydroxide solution and toluene 1 g: 1 g: 0.1 g: 2 mL: 40 mL, the Ni4O4 cubane, 3-bromocarbazole, tetrabutylammonium bromide and 0.02 mol / L sodium hydroxide solution are added into toluene to obtain a mixed solution, and the mixed solution is refluxed at 60°C for 8h to obtain Ni4O4 cubane modified carbazole.

[0023] Preparation Example 3 Preparation Example 3 provides a kind of Ni4O4 cubane modified carbazole, which is prepared by the following preparation method: (a) According to the amount ratio of nickel chloride, salicylaldehyde, triethylamine and formaldehyde 1 mol: 1.2 mol: 1.7 mol: 2 L, the nickel chloride, salicylaldehyde and triethylamine are added into the formaldehyde to stir until the precipitation no longer precipitates, the precipitate is filtered out, washed and dried to obtain Ni4O4 cubane; (b) According to the amount ratio of Ni4O4 cubane, 3-bromocarbazole, tetrabutylammonium bromide, 0.05 mol / L sodium hydroxide solution and toluene 1 g: 2 g: 0.1 g: 2 mL: 60 mL, the Ni4O4 cubane, 3-bromocarbazole, tetrabutylammonium bromide and 0.05 mol / L sodium hydroxide solution are added into toluene to obtain a mixed solution, and the mixed solution is refluxed at 80°C for 12h to obtain Ni4O4 cubane modified carbazole.

[0024] (II) Examples Example 1 Example 1 provides a preparation method of an iron-manganese-based sodium ion battery positive electrode material, and the specific steps are as follows: (1) According to the amount ratio of ferric nitrate, manganese nitrate, sodium carbonate, lanthanum telluride and water 1 mol: 1 mol: 0.8 mol: 0.3 mol: 10 L, the ferric nitrate and manganese nitrate are added into water to stir and dissolve to obtain a mixed solution; under the condition that air with a flow rate of 10 L / min is used as a carrier gas flow, the mixed solution is spray pyrolyzed at 600°C to obtain an iron-manganese oxide precursor, wherein the residence time of the carrier gas flow is 30 s; then the sodium carbonate, the iron-manganese oxide precursor and the lanthanum telluride are ball-mixed uniformly to obtain a mixture, and then the mixture is calcined at 900°C for 12 h in an argon atmosphere to obtain a composite material; (2) According to the amount ratio of Ni4O4cubane modified carbazole, manganese dioxide, composite material and 4 mol / L dilute sulfuric acid 10 g:4 g:0.8 g:45 mL, the Ni4O4cubane modified carbazole, composite material and manganese dioxide of Preparation Example 1 are added into dilute sulfuric acid and ultrasonically dispersed for 25 min, and stirred for reaction for 17 h. After the reaction is completed, centrifugation, washing and drying are performed to obtain a sodium ion positive electrode material.

[0025] Example 1 also provides an iron-manganese-based sodium ion battery positive electrode material prepared by the above preparation method.

[0026] The scanning electron microscope image of the iron-manganese-based sodium ion battery positive electrode material prepared in this example is shown in Figure 2 、 3 .

[0027] Example 2 Example 2 provides a preparation method of an iron-manganese-based sodium ion battery positive electrode material, and the specific steps are as follows: (1) According to the amount ratio of ferric nitrate, manganese nitrate, sodium carbonate, lanthanum telluride and water 1 mol:0.8 mol:0.8 mol:0.1 mol:4 L, the ferric nitrate and manganese nitrate are added into water and stirred to dissolve to obtain a mixed solution. Under the condition that air with a flow rate of 8 L / min is used as a carrier gas flow, the mixed solution is spray pyrolyzed at 500°C to obtain an iron-manganese oxide precursor, wherein the residence time of the carrier gas flow is 20 s. The sodium carbonate, iron-manganese oxide precursor and lanthanum telluride are ball-mixed uniformly to obtain a mixture, and then the mixture is calcined at 800°C for 10 h under an argon atmosphere at 900°C to obtain a composite material. (2) According to the amount ratio of Ni4O4cubane modified carbazole, manganese dioxide, composite material and 4 mol / L dilute sulfuric acid 10 g:4 g:0.5 g:40 mL, the Ni4O4cubane modified carbazole, composite material and manganese dioxide of Preparation Example 2 are added into dilute sulfuric acid and ultrasonically dispersed for 20 min, and stirred for reaction for 15 h. After the reaction is completed, centrifugation, washing and drying are performed to obtain a sodium ion positive electrode material.

[0028] Example 2 also provides an iron-manganese-based sodium ion battery positive electrode material prepared by the above preparation method.

[0029] Example 3 Example 3 provides a preparation method of an iron-manganese-based sodium ion battery positive electrode material, and the specific steps are as follows: (1) According to the amount ratio of ferric nitrate, manganese nitrate, sodium carbonate, lanthanum telluride and water 1 mol: 1.2 mol: 1 mol: 0.4 mol: 20 L, the ferric nitrate and manganese nitrate are added to water and stirred to dissolve to obtain a mixed solution, the mixed solution is sprayed pyrolyzed at 700 ℃ with air as the carrier gas at a flow rate of 12 L / min, the residence time of the carrier gas flow is 40 s, then the sodium carbonate, the iron-manganese oxide precursor and the lanthanum telluride are uniformly mixed by ball milling to obtain a mixture, and the mixture is calcined at 950 ℃ for 15 h in an argon atmosphere to obtain the composite material; (2) According to the amount ratio of Ni4O4 cubic alkane modified carbazole, manganese dioxide, composite material and 4 mol / L dilute sulfuric acid 10 g: 4-5 g: 1 g: 50 mL, the Ni4O4 cubic alkane modified carbazole, composite material and manganese dioxide prepared in Preparation Example 3 are added to dilute sulfuric acid and ultrasonically dispersed for 30 min, and stirred to react for 20 h, after the reaction is completed, centrifugation, washing and drying are carried out to obtain a sodium ion positive electrode material.

[0030] Example 3 also provides an iron-manganese-based sodium ion battery positive electrode material, which is prepared by the above preparation method.

[0031] (Three) Comparative Examples Comparative Example 1 Comparative Example 1 and Example 1 are basically the same, the difference is that the lanthanum telluride in step (1) of Example 1 is replaced by lanthanum oxide.

[0032] Comparative Example 2 Comparative Example 2 and Example 1 are basically the same, the difference is that the Ni4O4 cubic alkane modified carbazole in Example 1 is replaced by a mixture of Ni4O4 cubic alkane and 3-bromocarbazole, and the mass ratio of Ni4O4 cubic alkane to 3-bromocarbazole is 1:1.5.

[0033] (Four) Application Examples The sodium ion battery positive electrode materials prepared in Examples 1-3 and Comparative Examples 1-2 are used as sodium ion battery positive electrode materials, and the volume ratio of the positive electrode material, acetylene black and polyvinylidene fluoride is 8:1:1 to mix uniformly in N-methylpyrrolidone to obtain a positive electrode slurry, then the positive electrode slurry is coated on an aluminum foil, vacuum dried and cut to obtain a positive electrode sheet; metal sodium sheet is used as the negative electrode, 1 mol / L NaPF6 ethylene carbonate (EC) / dimethyl carbonate (DMC) / methyl ethyl carbonate (EMC) solution is used as the electrolyte, the volume ratio of EC, DMC and EMC is 1:1:0.5, glass fiber is used as the separator, and then a button cell is assembled in the order of negative electrode sheet, electrolyte, separator, electrolyte and positive electrode.

[0034] (Five) Test Examples The button cells prepared from Examples 1-3 and Comparative Examples 1-2 were placed in a blue light test system after standing for 4 h, and subjected to rate test and cycle test, respectively; Rate test: the test voltage was set to 2-4.2 V, and 0.5 C, 1 C and 2 C charge-discharge cycles were sequentially performed for 3 times to take the average charge-discharge capacity, and the test results are shown in Table 1.

[0035] Cycle test: the test voltage was set to 2-4.2 V, and 0.1 C charge-discharge was first performed for 3 times for activation, and then 1 C charge-discharge cycle was performed for 50 times, and the discharge specific capacity retention rate after 50 cycles was calculated, and the test results are shown in Table 1.

[0036] Table 1: Rate performance and cycle performance of examples and comparative examples As can be seen from Table 1, the button cells prepared from Examples 1-3 of the present application have high rate cycle stability, high specific capacity and excellent capacity retention rate.

[0037] Compared with Example 1, Comparative Example 1 replaces lanthanum telluride with lanthanum oxide, and Comparative Example 2 replaces Ni4O4 cubic alkane modified carbazole with a mixture of Ni4O4 cubic alkane and 3-bromo carbazole, and the rate test has large fluctuation, the specific capacity is reduced, and the capacity retention rate after 50 cycles is also significantly reduced. Specific analysis shows that: on the one hand, the present application dopes lanthanum telluride in the iron-manganese-based transition metal oxide positive electrode material for modification, and lanthanum telluride has excellent electronic conductivity, which can form a good electronic channel in the iron-manganese-based oxide and improve the problem of poor conductivity, and the lanthanum ion has a large ionic radius, which can increase the interlayer spacing of the material, reduce the diffusion resistance of sodium ions, improve the electronic transmission efficiency of the positive electrode material, and improve the rate performance and reversible capacity of the material. On the other hand, the present application coats the Ni4O4 cubic alkane modified carbazole on the surface of the composite material as a protective layer, and the carbazole unit has a large π conjugated plane, showing good conductivity and flexibility, which can effectively prevent the corrosion and damage of the electrolyte to the iron-manganese-based oxide, and inhibit the volume change caused by the sodium ion extraction and insertion during the cycle process, and improve the cycle stability of the positive electrode material.

[0038] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. The basic principles and main features of the present application have been described in the above embodiments, and some modifications or replacements can be made on the basis of the present application, but these modifications or replacements do not make the corresponding technical solutions deviate from the scope of the present application.

Claims

1. A method for preparing a ferromanganese-based sodium-ion battery cathode material, characterized in that, The preparation method comprises the following steps: (1) dissolving iron nitrate and manganese nitrate in water, and then obtaining an iron-manganese oxide precursor by spray pyrolysis; then mixing sodium carbonate, the iron-manganese oxide precursor and lanthanum telluride by ball milling, and obtaining a composite material by calcination under an inert gas atmosphere; (2) adding Ni4O4 cubic alkane modified carbazole, the composite material and manganese dioxide into dilute sulfuric acid, and then obtaining the iron-manganese-based sodium ion positive electrode material by ultrasonic dispersion, reaction under stirring, centrifugation, washing and drying.

2. The method of claim 1, wherein the method further comprises a step of mixing the iron-manganese based sodium-ion battery cathode material with a sodium source. In step (1), the molar ratio of the iron nitrate, manganese nitrate, sodium carbonate and lanthanum telluride is 1:(0.8-1.2):(0.8-1):(0.1-0.4). ​ 3. The method for preparing the iron-manganese-based sodium-ion battery cathode material according to claim 1, characterized in that, In step (1), the temperature of the spray pyrolysis is 500-700℃, the flow rate of the carrier gas stream is 8-12 L / min, the carrier gas stream is air, the residence time of the carrier gas stream is 20-40 s, the temperature of the calcination is 800-950℃, and the time of the calcination is 10-15 h.

4. The method for preparing the iron-manganese-based sodium-ion battery cathode material according to claim 1, characterized in that, In step (2), the mass ratio of the Ni4O4 cubic alkane modified carbazole, manganese dioxide and composite material is 10:(4-5):(0.5-1), the concentration of the dilute sulfuric acid is 4 mol / L, and the reaction time is 15-20 h.

5. The method of making a ferromanganese-based cathode material for sodium-ion batteries according to claim 1, characterized in that, In step (2), the Ni4O4 cubic alkane modified carbazole is prepared by the following preparation process: (a) adding nickel chloride, salicylaldehyde and triethylamine into methanol, stirring until no more precipitate is precipitated, and then obtaining the Ni4O4 cubic alkane by filtration, washing and drying; (b) adding the Ni4O4 cubic alkane, 3-bromocarbazole, tetrabutylammonium bromide and a sodium hydroxide solution into toluene, and then obtaining the Ni4O4 cubic alkane modified carbazole by reflux reaction.

6. The method of producing an iron-manganese-based sodium-ion battery cathode material according to claim 5, characterized in that, In step (a), the molar ratio of the nickel chloride, salicylaldehyde and triethylamine is 1:(0.8-1.2):(1.5-1.7).

7. The method of producing an iron-manganese-based cathode material for sodium-ion batteries according to claim 5, characterized in that, In step (b), the amount ratio of the Ni4O4 cubic alkane, 3-bromocarbazole, tetrabutylammonium bromide and the sodium hydroxide solution is 1 g:(1-2) g:0.1 g:2 mL, the concentration of the sodium hydroxide solution is 0.02-0.05 mol / L, the temperature of the reflux reaction is 60-80℃, and the time of the reflux reaction is 8-12 h.

8. An iron-manganese-based sodium-ion battery cathode material, characterized in that, The iron-manganese-based sodium ion battery positive electrode material is prepared by the preparation method of any one of claims 1-7.

9. The application of the iron-manganese-based sodium ion battery positive electrode material of claim 8 in a sodium ion battery.

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