Sodium-ion battery cathode material carbonate precursor and oxide precursor, and preparation method and application thereof

Abstract

The application relates to the technical field of sodium ion batteries, and discloses a sodium ion battery positive electrode material carbonate precursor and an oxide precursor as well as a preparation method and application thereof, the specific surface area of the carbonate precursor is 150-250 m 2 / g, the specific surface area of the oxide precursor is 31-70 m 2 / g; the chemical general formula of the carbonate precursor is Ni x Mn y Ti z Me 1‑x‑y‑z CO3, the chemical general formula of the oxide precursor is Ni x Mn y Ti z Me 1‑x‑y‑z O; wherein 0.3<=x<=0.65, 0.3<=y<=0.65, 0.005<=z<=0.2, 0<=1-x-y-z<=0.395; Me includes at least one of Cu, Fe, Ca, Zn, Al, Mg and Zr. The specific surface area of the carbonate precursor and the oxide precursor provided by the application is in a suitable range, element distribution uniformity is good, and the stability and cycle performance under high voltage of the material are improved.

Description

Technical Field

[0001] This invention relates to the field of sodium-ion battery technology, specifically to a carbonate precursor and an oxide precursor for sodium-ion battery cathode materials, their preparation methods, and applications. Background Technology

[0002] Sodium-ion batteries, due to their abundant sodium reserves, considerable energy density, low cost, low-temperature resistance, safety, and convenience, are expected to see rapid development in multiple fields such as electric vehicles, electric boats, home / industrial energy storage, and smart grids. With technological advancements and cost reductions, sodium-ion batteries are highly competitive in the grid energy storage field. Developing sodium-ion batteries can reduce or avoid the use of expensive elements such as lithium, cobalt, and nickel, lowering energy storage costs and potentially making them an excellent alternative to lithium-ion batteries.

[0003] The energy density of sodium-ion batteries is a key factor affecting the driving range of electric vehicles. Compared to mature lithium-ion batteries, sodium-ion batteries are at a disadvantage in terms of energy density. The generally accepted energy density range for lithium-ion batteries is 100-300 Wh / kg, while the current best sodium-ion batteries only have an energy density of 160 Wh / kg. Although sodium-ion battery technology is not as mature as lithium-ion batteries, it is gradually gaining attention and is expected to become an ideal choice in situations where lithium resources are scarce. Summary of the Invention

[0004] This invention provides a carbonate precursor and an oxide precursor for sodium-ion battery cathode materials, their preparation methods, and applications, which can yield sodium-ion battery cathode materials with high energy density, excellent capacity, and superior cycle performance.

[0005] To achieve the above objectives, a first aspect of the present invention provides a carbonate precursor for a sodium-ion battery cathode material, wherein the carbonate precursor has a specific surface area of ​​150-250 m². 2 / g, the general chemical formula of the carbonate precursor is Ni x Mn y Ti z Me 1-x-y-z CO3, wherein 0.3≤x≤0.65, 0.3≤y≤0.65, 0.005≤z≤0.2, 0≤1-xyz≤0.395; Me includes at least one of Cu, Fe, Ca, Zn, Al, Mg, and Zr.

[0006] Optionally, the particle size distribution (D90-D10) / D50 of the carbonate precursor is 0.7-1.1.

[0007] Optionally, the tap density of the carbonate precursor is 0.8-1.3 g / cm³. 3 .

[0008] Optionally, the D50 value of the carbonate precursor is 2.5-8 μm.

[0009] Optionally, the carbonate precursor comprises a plurality of secondary particles composed of primary particles; optionally, the primary particles are in the form of thin flakes.

[0010] A second aspect of the present invention provides an oxide precursor for a sodium-ion battery cathode material, wherein the oxide precursor has a specific surface area of ​​31-70 m². 2 / g; the general chemical formula of the oxide precursor is Ni x Mn y Ti z Me 1-x-y-z O, where 0.3≤x≤0.65, 0.3≤y≤0.65, 0.005≤z≤0.2, 0≤1-xyz≤0.395; Me includes at least one of Cu, Fe, Ca, Zn, Al, Mg, and Zr.

[0011] Optionally, the particle size distribution (D90-D10) / D50 of the oxide precursor is 0.7-1.0.

[0012] Optionally, the tap density of the oxide precursor is 0.9-1.3 g / cm³. 3 .

[0013] Optionally, the D50 value of the oxide precursor is 3-8 μm.

[0014] A third aspect of the present invention provides a method for preparing a carbonate precursor for a sodium-ion battery cathode material as described in the first aspect, the method comprising:

[0015] A first mixture of water, complexing agent, and pH adjuster is prepared to obtain a base solution; the conditions are controlled such that the volume content of oxygen in the base solution is <1%;

[0016] The metal salt solution and the precipitant are simultaneously introduced into the reaction system formed with the base liquid for a second mixing. The flow rate of the precipitant is controlled so that the pH value of the reaction system is gradually reduced from 9.1-9.3 during the nucleation period to 8.1-8.3 during the control period, thereby obtaining the carbonate precursor.

[0017] The metal salt solution includes sulfuric acid, and the precipitant includes ammonium sulfate.

[0018] According to a preferred embodiment, the method satisfies at least one of the following conditions:

[0019] A. The metal salt solution includes Ni, Mn, and Ti elements;

[0020] Optionally, the metal salt solution further includes at least one of the elements Cu, Fe, Ca, Zn, Al, Mg, and Zr;

[0021] B. The complexing agent is selected from at least one of tartaric acid, citric acid, oxalic acid, ammonium sulfate, and ammonia water;

[0022] C. The pH adjuster and the precipitant are each independently selected from at least one of ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate;

[0023] D. In the underlying solution, the concentration of the complexing agent is 0.01-0.1 mol / L;

[0024] E. The molar ratio of the metal salt solution to the precipitant is 1:1.2-1.5;

[0025] F. The metal salt solution includes at least one of the following: a hydrochloride solution, a sulfate solution, and a nitrate solution of the metal element; the sum of the concentrations of the metal elements in the metal salt solution is 3-5 mol / L;

[0026] G. The concentration of the sulfuric acid in the metal salt solution is 0.005-0.01 mol / L;

[0027] H. The concentration of ammonium sulfate in the precipitant is 0.05-0.1 mol / L;

[0028] I. The second mixing is carried out in a reactor, wherein the flow rate of the metal salt solution introduced into the reactor is 6% to 10% of the total capacity of the reactor;

[0029] J. The duration of the nucleation period is 1.5-2.5 h, and the rate of decrease of the gradually decreasing pH value is 0.1-0.3 / h;

[0030] K. The conditions for the second mixing are: temperature 30-60℃; stirring speed 600-900rpm.

[0031] A fourth aspect of the present invention provides a method for preparing a sodium-ion battery cathode material oxide precursor as described in the second aspect, the method comprising:

[0032] Provides a carbonate precursor as described in the first aspect, or a carbonate precursor prepared by the method described in the third aspect.

[0033] The carbonate precursor is sintered to obtain the oxide precursor.

[0034] Optionally, the sintering temperature is 550-650℃, and the sintering time is 4-6 hours.

[0035] The fifth aspect of the present invention provides a sodium-ion battery cathode material, wherein the raw materials of the sodium-ion battery cathode material include the sodium-ion battery cathode material carbonate precursor described in the first aspect, or the sodium-ion battery cathode material oxide precursor described in the second aspect.

[0036] A sixth aspect of the present invention provides a sodium-ion battery comprising the sodium-ion battery cathode material as described in the fifth aspect.

[0037] A seventh aspect of the present invention provides an electrical device including a sodium-ion battery as described in the sixth aspect.

[0038] The technical solution provided by this invention has at least the following advantages:

[0039] The sodium-ion battery cathode material carbonate precursor provided by this invention has a high specific surface area, and the precursor composition is based on nickel and manganese and doped with titanium. On the one hand, the large specific surface area increases the contact area between the material and hot air, which is beneficial for sodium infiltration during the cathode material sintering process, improving energy density and uniformity of element distribution, thereby increasing battery capacity. On the other hand, the Ti-O bond provided by titanium improves oxygen stability, thereby suppressing oxygen vacancies and structural degradation, ultimately improving the stability of the material and cycle performance under high voltage.

[0040] The method for preparing carbonate precursors provided by this invention, by controlling the volume content of oxygen and pH value in the reaction system, and by using a metal salt solution containing sulfuric acid and a precipitant containing ammonium sulfate, coupled verification of various process parameters yields optimal parameter values, thus preparing a titanium-doped carbonate precursor with a high specific surface area. Introducing Ti element during the co-precipitation process of precursor preparation results in a more uniform element distribution and better doping effect compared to solid-phase doping. Attached Figure Description

[0041] Figure 1 This is a SEM image (magnification 50K) of the carbonate precursor prepared in Example 1 of this invention;

[0042] Figure 2 This is a SEM image (magnification 10K) of the carbonate precursor prepared in Example 1 of this invention;

[0043] Figure 3 This is a SEM image (magnification 50K) of the oxide precursor prepared in Example 1 of this invention;

[0044] Figure 4 This is a SEM image (magnification 10K) of the oxide precursor prepared in Example 1 of this invention;

[0045] Figure 5This is a SEM image of the cathode material prepared in Example 1 of this invention. Detailed Implementation

[0046] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0047] It should be noted that, in all aspects of the present invention, the same components or terms in each aspect are described only once in one aspect and not repeatedly, and those skilled in the art should not understand this as a limitation of the present invention.

[0048] As mentioned above, the first aspect of the present invention provides a carbonate precursor for a sodium-ion battery cathode material, wherein the specific surface area of ​​the carbonate precursor is 150-250 m². 2 / g, for example, can be 150m 2 / g, 160m 2 / g、170m 2 / g、180m 2 / g、190m 2 / g、200m 2 / g、210m 2 / g、220m 2 / g、230m 2 / g、240m 2 / g、250m 2 / g or 150-250m 2 Any value between / g. The general chemical formula of the carbonate precursor is Ni. x Mn y TizMe 1-x-y-z CO3, wherein 0.3≤x≤0.65, 0.3≤y≤0.65, 0.005≤z≤0.2, 0≤1-xyz≤0.395; Me includes at least one of Cu, Fe, Ca, Zn, Al, Mg, and Zr.

[0049] The carbonate precursor has a large specific surface area, and the precursor composition is based on nickel and manganese and doped with titanium. On the one hand, the large specific surface area is conducive to the infiltration of sodium during the sintering process of the cathode material, which improves the energy density and the uniformity of element distribution, thereby increasing the battery capacity. On the other hand, the Ti-O bond provided by titanium improves the stability of oxygen, thereby inhibiting oxygen vacancies and structural degradation, ultimately improving the stability of the material and the cycle performance under high voltage.

[0050] Furthermore, the high specific surface area of ​​the precursor is beneficial for the single crystallization of the subsequently prepared cathode material, reducing the sintering temperature and sintering time. However, an excessively high specific surface area can increase centrifugation difficulties, leading to moisture reabsorption and agglomeration in the finished product. Therefore, the specific surface area of ​​the carbonate precursor in this invention should be within a suitable range and should not be too high.

[0051] In this invention, if z < 0.005, the Ti doping amount is low, which has little impact on the structural adjustment of the material and cannot achieve the modification result; if z > 0.2, the Ti doping amount is too large, which has a negative impact on the capacity of the material.

[0052] Optionally, the specific surface area of ​​the carbonate precursor is 180-245 m². 2 / g.

[0053] Optionally, the general chemical formula of the carbonate precursor is Ni x Mn y Ti z Me 1-x-y-z CO3, wherein 0.3≤x≤0.4, 0.3≤y≤0.4, 0.1≤z≤0.2, 0.1≤1-xyz≤0.2; Me includes at least one of Cu and Fe.

[0054] In some embodiments, the particle size distribution (D90-D10) / D50 of the carbonate precursor is 0.7-1.1, for example, it can be any value between 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, or 0.7-1.1. Optionally, the particle size distribution of the carbonate precursor is 0.8-1.1.

[0055] In some embodiments, the tap density of the carbonate precursor is 0.8-1.3 g / cm³. 3 For example, it can be 0.80 g / cm³. 3 0.85g / cm 3 0.90g / cm 3 0.95g / cm 3 1.00g / cm 3 1.05g / cm 3 1.10 g / cm 3 1.15g / cm 3 1.20g / cm 3 1.25g / cm 3 1.30g / cm 3 or 0.8-1.3 g / cm³ 3 Any value between these ranges; optionally, the tap density of the carbonate precursor is 1.0-1.2 g / cm³. 3.

[0056] In some embodiments, the D50 value of the carbonate precursor is 2.5-8 μm, for example, it can be any value between 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, 5.0 μm, 5.5 μm, 6.0 μm, 6.5 μm, 7.0 μm, 7.5 μm, 8.0 μm, or 2.5-8 μm. Optionally, the D50 value of the carbonate precursor is 3.0-6.0 μm.

[0057] In some embodiments, the carbonate precursor comprises a plurality of secondary particles consisting of primary particles; optionally, the primary particles are in the form of thin flakes.

[0058] As previously stated, a second aspect of the present invention provides an oxide precursor for a sodium-ion battery cathode material, the oxide precursor having a specific surface area of ​​31-70 m². 2 / g, for example, can be 31m 2 / g、35m 2 / g、40m 2 / g、45m 2 / g, 50m 2 / g、55m 2 / g、60m 2 / g、65m 2 / g、70m 2 / g or 31-70m 2 Any value between / g. The general chemical formula of the oxide precursor is Ni. x Mn y Ti z Me 1-x-y-z O, where 0.3≤x≤0.65, 0.3≤y≤0.65, 0.005≤z≤0.2, 0≤1-xyz≤0.395; Me includes at least one of Cu, Fe, Ca, Zn, Al, Mg, and Zr.

[0059] Optionally, the specific surface area of ​​the oxide precursor is 31-65 m². 2 / g.

[0060] Optionally, the general chemical formula of the oxide precursor is Ni. x Mn y Ti z Me 1-x-y-z O, where 0.3≤x≤0.4, 0.3≤y≤0.4, 0.1≤z≤0.2, 0.1≤1-xyz≤0.2; Me includes at least one of Cu and Fe.

[0061] In some embodiments, the particle size distribution (D90-D10) / D50 of the oxide precursor is 0.7-1.0, for example, it can be any value between 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00 or 0.7-1.0.

[0062] In some embodiments, the tap density of the oxide precursor is 0.9-1.3 g / cm³. 3 For example, it can be 0.90 g / cm³ 3 0.95g / cm 3 1.00g / cm 3 1.05g / cm 3 1.10 g / cm 3 1.15g / cm 3 1.20g / cm 3 1.25g / cm 3 1.30g / cm 3 or 0.9-1.3 g / cm³ 3 Any value between.

[0063] In some embodiments, the D50 value of the oxide precursor is 3-8 μm, for example, it can be any value between 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, 5.0 μm, 5.5 μm, 6.0 μm, 6.5 μm, 7.0 μm, 7.5 μm, 8.0 μm, or 3-8 μm. Optionally, the D50 value of the oxide precursor is 3-6 μm.

[0064] As previously described, a third aspect of the present invention provides a method for preparing a carbonate precursor for a sodium-ion battery cathode material as described in the first aspect, the method comprising:

[0065] A first mixture of water, complexing agent, and pH adjuster is prepared to obtain a base solution; the conditions are controlled such that the volume content of oxygen in the base solution is <1%;

[0066] The metal salt solution and the precipitant are simultaneously introduced into the reaction system formed with the base liquid for a second mixing. The flow rate of the precipitant is controlled so that the pH value of the reaction system is gradually reduced from 9.1-9.3 during the nucleation period to 8.1-8.3 during the control period, thereby obtaining the carbonate precursor.

[0067] The metal salt solution includes sulfuric acid, and the precipitant includes ammonium sulfate.

[0068] In some embodiments, the metal salt solution includes Ni, Mn, and Ti elements.

[0069] Optionally, the metal salt solution may further include at least one of the elements Cu, Fe, Ca, Zn, Al, Mg, and Zr.

[0070] In some embodiments, the complexing agent is selected from at least one of tartaric acid, citric acid, oxalic acid, ammonium sulfate, and ammonia.

[0071] In some embodiments, the pH adjuster and the precipitant are each independently selected from at least one of ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate.

[0072] In some embodiments, the concentration of the complexing agent in the base solution is 0.01-0.1 mol / L.

[0073] In some embodiments, the molar ratio of the metal salt solution to the precipitant is 1:1.2-1.5.

[0074] In some embodiments, the metal salt solution includes at least one of the following: a hydrochloride solution, a sulfate solution, and a nitrate solution of the metal element; the sum of the concentrations of the metal element in the metal salt solution is 3-5 mol / L.

[0075] In some embodiments, the concentration of sulfuric acid in the metal salt solution is 0.005-0.01 mol / L.

[0076] In some embodiments, the concentration of ammonium sulfate in the precipitant is 0.05-0.1 mol / L.

[0077] In some embodiments, the second mixing is carried out in a reactor, and the flow rate of the metal salt solution introduced into the reactor is 6% to 10% of the total capacity of the reactor, for example, it can be any value of 6%, 7%, 8%, 9%, 10% or 6% to 10% / h.

[0078] In some embodiments, the nucleation period lasts for 1.5-2.5 hours, and the gradually decreasing pH value decreases at a rate of 0.1-0.3 h / h, for example, any value between 0.1 / h, 0.2 / h, 0.3 / h, or 0.1-0.3 / h, preferably 0.1-0.2 / h. A too rapid rate of pH decrease may lead to the formation of larger primary particles, thus affecting the specific surface area of ​​the carbonate precursor. This invention adjusts the flow rate of the precipitant according to a preferred pH control curve, thereby controlling the pH value of the reaction process. By adjusting the pH value, the amount of nuclei produced and the growth rate of the reaction process are controlled to obtain the carbonate precursor product that meets the required specifications.

[0079] In some embodiments, the conditions for the second mixing are: a temperature of 30-60°C, for example, any value between 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, or 30-60°C; and a stirring speed of 600-900 rpm, for example, any value between 600 rpm, 650 rpm, 700 rpm, 750 rpm, 800 rpm, 850 rpm, 900 rpm, or 600-900 rpm. This invention, at a lower reaction temperature, obtains a carbonate precursor with a higher specific surface area by controlling the pH value and oxygen volume content during the reaction process, resulting in a disordered arrangement of fine, thin, flake-like primary particles that extend radially to form a loose, porous structure.

[0080] Optionally, the method for preparing the sodium-ion battery cathode material carbonate precursor of the present invention involves introducing a specific amount of sulfuric acid into a metal salt solution and a specific amount of ammonium sulfate into a precipitant, and then simultaneously introducing both into the reaction system for the second mixing. The former can inhibit the hydrolysis of titanium solution and make each element precipitate uniformly, while the latter can refine the primary morphology, which is more conducive to obtaining a precursor material with excellent performance.

[0081] The preparation method of the sodium-ion battery cathode material carbonate precursor according to the present invention may also include post-processing methods known in the art, such as centrifugation, washing, and demagnetization, so as to obtain the carbonate precursor with better quality. The present invention will not elaborate further here, and those skilled in the art should not understand it as a limitation of the present invention.

[0082] As previously described, a fourth aspect of the present invention provides a method for preparing a sodium-ion battery cathode material oxide precursor as described in the second aspect, the method comprising:

[0083] The carbonate precursor described in the first aspect or prepared by the method for preparing the carbonate precursor described in the third aspect is provided, and the carbonate precursor is sintered to obtain the oxide precursor.

[0084] Optionally, the sintering temperature is 550-650℃, for example, it can be any value between 550℃, 580℃, 600℃, 620℃, 650℃, or 550-650℃; the sintering time is 4-6h, for example, it can be any value between 4.0h, 4.5h, 5.0h, 5.5h, 6.0h, or 4-6h.

[0085] As previously stated, the fifth aspect of the present invention provides a sodium-ion battery cathode material, wherein the raw materials of the sodium-ion battery cathode material include the sodium-ion battery cathode material carbonate precursor described in the first aspect, or the sodium-ion battery cathode material oxide precursor described in the second aspect.

[0086] This invention does not impose any particular limitations on the method for preparing sodium-ion battery cathode materials using the carbonate precursor and / or oxide precursor provided by this invention; those skilled in the art can choose from known techniques. However, in order to obtain a battery cathode material with superior electrochemical performance, this invention preferably uses the following method to prepare the sodium-ion battery cathode material.

[0087] According to a preferred embodiment, the method for preparing the sodium-ion battery cathode material includes: calcining the oxide precursor and the sodium compound in the presence of an oxygen-containing atmosphere to obtain the sodium-ion battery cathode material.

[0088] Optionally, the calcination conditions include: a temperature of 800-1200℃, for example, 800℃, 900℃, 1000℃, 1100℃, 1200℃, or any value between 800-1200℃; and a time of 10-15h, for example, 10h, 11h, 12h, 13h, 14h, 15h, or any value between 10-15h.

[0089] As previously described, a sixth aspect of the present invention provides a sodium-ion battery comprising the sodium-ion battery cathode material as described in the fifth aspect.

[0090] As previously described, a seventh aspect of the present invention provides an electrical device including a sodium-ion battery as described in the sixth aspect.

[0091] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, the raw materials are all commercially available products.

[0092] Example 1

[0093] Prepare a chemical formula ((Ni 0.40 Mn 0.33 Ti 0.15 Cu 0.12 The oxide precursor of O is prepared by the following method:

[0094] ① Raw material preparation: Dissolve nickel sulfate, manganese chloride, titanium oxysulfate, and copper sulfate pentahydrate crystals to form a mixed metal salt solution with a nickel ion concentration of 83±5 g / L, a manganese ion concentration of 64±5 g / L, a titanium ion concentration of 25±5 g / L, and a copper ion concentration of 27±5 g / L. Add dilute sulfuric acid to the mixed metal salt solution to make the sulfuric acid concentration in the metal salt solution 0.01 mol / L. Prepare an ammonium carbonate solution with a concentration of 300±20 g / L. Add ammonium sulfate to the ammonium carbonate solution to make the ammonium sulfate concentration in the ammonium carbonate solution 0.1 mol / L.

[0095] ② Add pure water, tartaric acid solution, and ammonium carbonate solution to the reaction vessel to obtain the bottom liquid, wherein the concentration of tartaric acid in the bottom liquid is 0.1 mol / L, and nitrogen gas is introduced to make the oxygen volume content 0.3%.

[0096] ③ Heat the reactor to 50℃, control the stirring speed at 800rpm, and simultaneously pump in a metal salt solution (containing dilute sulfuric acid) and an ammonium carbonate solution (containing ammonium sulfate). The metal salt solution (containing dilute sulfuric acid) is introduced at 8% / h of the total reactor capacity, and the ammonium carbonate solution (containing ammonium sulfate) is introduced at 20% / h of the total reactor capacity. Control the actual pH value during the reaction process, gradually decreasing the pH value from 9.20 during the nucleation period to 8.20 during the control period. The duration of the nucleation period is 2h, and the rate of pH decrease is 0.1 / h. The reaction yields a nickel-manganese-titanium-copper carbonate precursor.

[0097] ④ After the synthesis stage is completed, the material is centrifuged, washed, demagnetized, and pre-sintered at 600℃ for 5 hours to obtain the oxide precursor.

[0098] Figure 1 and Figure 2 SEM images of the carbonate precursor prepared in this embodiment at different magnifications, from... Figure 1 and Figure 2 It can be seen that the loose and porous morphology of carbonate is composed of fine, thin, flaky primary particles.

[0099] Figure 3 and Figure 4 These are SEM images of the oxide precursor prepared in this embodiment at different magnifications. Figure 3 and Figure 4 It can be seen that the oxide has a loose and porous morphology composed of extremely fine particles.

[0100] Example 2

[0101] Prepare a chemical formula ((Ni 0.333 Mn 0.333 Ti 0.167 Mg 0.167 The oxide precursor of O is prepared by the following method:

[0102] ① Raw material preparation: Dissolve nickel sulfate, manganese chloride, titanium oxysulfate, and magnesium sulfate heptahydrate crystals to form a mixed metal salt solution with a nickel ion concentration of 69±5 g / L, a manganese ion concentration of 65±5 g / L, a titanium ion concentration of 28±5 g / L, and a magnesium ion concentration of 38±5 g / L. Add dilute sulfuric acid to the mixed metal salt solution to make the sulfuric acid concentration in the metal salt solution 0.01 mol / L. Prepare an ammonium carbonate solution with a concentration of 300±20 g / L. Add ammonium sulfate to the ammonium carbonate solution to make the ammonium sulfate concentration in the ammonium carbonate solution 0.1 mol / L.

[0103] ② Add pure water, tartaric acid solution, and ammonium carbonate solution to the reaction vessel to obtain the bottom liquid, wherein the concentration of tartaric acid in the bottom liquid is 0.1 mol / L, and nitrogen gas is introduced to make the oxygen volume content 0.3%.

[0104] ③ Heat the reactor to 50℃, control the stirring speed at 800rpm, and simultaneously pump in a metal salt solution (containing dilute sulfuric acid) and an ammonium carbonate solution (containing ammonium sulfate). The metal salt solution (containing dilute sulfuric acid) is introduced at 8% / h of the total reactor capacity, and the ammonium carbonate solution (containing ammonium sulfate) is introduced at 20% / h of the total reactor capacity. Control the actual pH value during the reaction process, gradually decreasing the pH value from 9.20 during the nucleation period to 8.20 during the control period. The duration of the nucleation period is 2h, and the rate of decrease of the pH value is 0.1 / h. The reaction yields a nickel-manganese-titanium-magnesium carbonate precursor.

[0105] ④ After the synthesis stage is completed, the material is centrifuged, washed, demagnetized, and pre-sintered at 600℃ for 5 hours to obtain the oxide precursor.

[0106] Example 3

[0107] Prepare a chemical formula ((Ni 0.4 Mn 0.3 Ti 0.1 Fe 0.2 The oxide precursor of O is prepared by the following method:

[0108] ① Raw material preparation: Dissolve nickel sulfate, manganese chloride, titanium oxysulfate, and ferrous sulfate crystals to form a mixed metal salt solution with a nickel ion concentration of 82±5 g / L, a manganese ion concentration of 57±5 g / L, a titanium ion concentration of 17±5 g / L, and a ferrous ion concentration of 44±5 g / L. Add dilute sulfuric acid to the mixed metal salt solution to make the sulfuric acid concentration in the metal salt solution 0.01 mol / L. Prepare an ammonium carbonate solution with a concentration of 300±20 g / L. Add ammonium sulfate to the ammonium carbonate solution to make the ammonium sulfate concentration in the ammonium carbonate solution 0.1 mol / L.

[0109] ② Add pure water, tartaric acid solution, and ammonium carbonate solution to the reaction vessel to obtain the bottom liquid, wherein the concentration of tartaric acid in the bottom liquid is 0.1 mol / L, and nitrogen gas is introduced to make the oxygen volume content 0.3%.

[0110] ③ Heat the reactor to 50℃, control the stirring speed at 800rpm, and simultaneously pump in a metal salt solution (containing dilute sulfuric acid) and an ammonium carbonate solution (containing ammonium sulfate). The metal salt solution (containing dilute sulfuric acid) is introduced at 8% / h of the total reactor capacity, and the ammonium carbonate solution (containing ammonium sulfate) is introduced at 20% / h of the total reactor capacity. Control the actual pH value during the reaction process, gradually decreasing the pH value from 9.20 during the nucleation period to 8.20 during the control period. The duration of the nucleation period is 2 hours, and the rate of pH decrease is 0.1 / h. The reaction yields a nickel-manganese-titanium-iron carbonate precursor.

[0111] ④ After the synthesis stage is completed, the material is centrifuged, washed, demagnetized, and pre-sintered at 600℃ for 5 hours to obtain the oxide precursor.

[0112] Example 4

[0113] Prepare a chemical formula ((Ni 0.40 Mn 0.33 Ti 0.15 Cu 0.12 The oxide precursor of O is prepared by the following method:

[0114] ① Raw material preparation: Dissolve nickel sulfate, manganese chloride, titanium oxysulfate, and copper sulfate pentahydrate crystals to form a mixed metal salt solution with a nickel ion concentration of 83±5 g / L, a manganese ion concentration of 64±5 g / L, a titanium ion concentration of 25±5 g / L, and a copper ion concentration of 27±5 g / L. Add dilute sulfuric acid to the mixed metal salt solution to make the sulfuric acid concentration in the metal salt solution 0.01 mol / L. Prepare an ammonium carbonate solution with a concentration of 300±20 g / L. Add ammonium sulfate to the ammonium carbonate solution to make the ammonium sulfate concentration in the ammonium carbonate solution 0.1 mol / L.

[0115] ② Add pure water, tartaric acid solution, and ammonium carbonate solution to the reaction vessel to obtain the bottom liquid, wherein the concentration of tartaric acid in the bottom liquid is 0.1 mol / L, and nitrogen gas is introduced to make the oxygen volume content 0.3%.

[0116] ③ Heat the reactor to 50℃, control the stirring speed at 800 rpm, and simultaneously pump in a metal salt solution (containing dilute sulfuric acid) and an ammonium carbonate solution (containing ammonium sulfate). The metal salt solution (containing dilute sulfuric acid) is introduced at 8% / h of the total reactor capacity, and the ammonium carbonate solution (containing ammonium sulfate) is introduced at 20% / h of the total reactor capacity. Control the actual pH value during the reaction process, gradually decreasing the pH value from 9.20 during the nucleation period to 8.20 during the control period. The duration of the nucleation period is 2 hours, and the rate of pH decrease is 0.3 / h. The reaction yields a nickel-manganese-titanium-copper carbonate precursor.

[0117] ④ After the synthesis stage is completed, the material is centrifuged, washed, demagnetized, and pre-sintered at 600℃ for 5 hours to obtain the oxide precursor.

[0118] Example 5

[0119] Prepare a chemical formula (Ni 0.4 Mn 0.3 Ti 0.1 Fe 0.2 The preparation method of the carbonate precursor of CO3 is the same as steps ①-③ of Example 3, except that in step ④, the synthesis stage ends and only post-processing is performed without calcination.

[0120] Comparative Example 1

[0121] Prepare a chemical formula ((Ni 0.40 Mn 0.33 Ti 0.15 Cu 0.12 The oxide precursor of O is prepared by the following method:

[0122] ① Raw material preparation: Dissolve nickel sulfate, manganese chloride, titanium oxysulfate, and copper sulfate pentahydrate crystals to form a mixed metal salt solution with a nickel ion concentration of 83±5 g / L, a manganese ion concentration of 64±5 g / L, a titanium ion concentration of 25±5 g / L, and a copper ion concentration of 27±5 g / L. Add dilute sulfuric acid to the mixed metal salt solution to make the sulfuric acid concentration in the metal salt solution 0.01 mol / L. Prepare an ammonium carbonate solution with a concentration of 300±20 g / L. Add ammonium sulfate to the ammonium carbonate solution to make the ammonium sulfate concentration in the ammonium carbonate solution 0.1 mol / L.

[0123] ② Add pure water, tartaric acid solution, and ammonium carbonate solution to the reaction vessel to obtain the bottom liquid, wherein the concentration of tartaric acid in the bottom liquid is 0.1 mol / L, and nitrogen gas is introduced to make the oxygen volume content 1%.

[0124] ③ Heat the reactor to 50℃, control the stirring speed at 800rpm, and simultaneously pump in metal salt solution and ammonium carbonate solution (containing ammonium sulfate). Pour in metal salt solution (containing dilute sulfuric acid) at 8% / h of the total reactor capacity and ammonium carbonate solution (containing ammonium sulfate) at 30% / h of the total reactor capacity. Control the actual pH value during the reaction process, gradually decreasing the pH value from 9.70 during the nucleation period to 8.70 during the control period. The duration of the nucleation period is 2h, and the rate of pH decrease is 0.1 / h. The reaction yields nickel-manganese-titanium-copper carbonate precursors.

[0125] ④ After the synthesis stage is completed, the material is centrifuged, washed, demagnetized, and pre-sintered at 600℃ for 5 hours to obtain the oxide precursor.

[0126] Comparative Example 2

[0127] Prepare a chemical formula ((Ni 0.333 Mn0.333 Ti 0.167 Mg 0.167 The oxide precursor of O is prepared by the following method:

[0128] ① Raw material preparation: Dissolve nickel sulfate, manganese chloride, titanium oxysulfate, and magnesium sulfate heptahydrate crystals to form a mixed metal salt solution with a nickel ion concentration of 69±5 g / L, a manganese ion concentration of 65±5 g / L, a titanium ion concentration of 28±5 g / L, and a magnesium ion concentration of 38±5 g / L. Add dilute sulfuric acid to the mixed metal salt solution to make the sulfuric acid concentration in the metal salt solution 0.01 mol / L. Prepare an ammonium carbonate solution with a concentration of 300±20 g / L. Add ammonium sulfate to the ammonium carbonate solution to make the ammonium sulfate concentration in the ammonium carbonate solution 0.1 mol / L.

[0129] ② Add pure water, tartaric acid solution, and ammonium carbonate solution to the reaction vessel to obtain the bottom liquid, wherein the concentration of tartaric acid in the bottom liquid is 0.1 mol / L, and nitrogen gas is introduced to make the oxygen volume content 1%.

[0130] Nitrogen gas was introduced to make the oxygen content 0.3%, the reactor was heated to 50°C, and the stirring speed was controlled at 800 rpm.

[0131] ③ Heat the reactor to 50℃, control the stirring speed at 800rpm, and simultaneously pump in metal salt solution and ammonium carbonate solution (containing ammonium sulfate). The metal salt solution (containing dilute sulfuric acid) is introduced at 8% / h of the total reactor capacity, and the ammonium carbonate solution (containing ammonium sulfate) is introduced at 30% / h of the total reactor capacity. Control the actual pH value during the reaction process, and gradually reduce the pH value from 9.70 during the nucleation period to 8.70 during the control period. The duration of the nucleation period is 2h, and the rate of pH reduction is 0.1 / h. The reaction yields nickel manganese titanium magnesium carbonate precursor.

[0132] ④ After the synthesis stage is completed, the material is centrifuged, washed, demagnetized, and pre-sintered at 600℃ for 5 hours to obtain the oxide precursor.

[0133] Comparative Example 3

[0134] Prepare a chemical formula ((Ni 0.4 Mn 0.3 Ti 0.1 Fe 0.2 The oxide precursor of O is prepared by the following method:

[0135] ① Raw material preparation: Dissolve nickel sulfate, manganese chloride, titanium oxysulfate, and ferrous sulfate crystals to form a mixed metal salt solution with a nickel ion concentration of 82±5 g / L, a manganese ion concentration of 57±5 g / L, a titanium ion concentration of 17±5 g / L, and a ferrous ion concentration of 44±5 g / L. Add dilute sulfuric acid to the mixed metal salt solution to make the sulfuric acid concentration in the metal salt solution 0.01 mol / L. Prepare an ammonium carbonate solution with a concentration of 300±20 g / L. Add ammonium sulfate to the ammonium carbonate solution to make the ammonium sulfate concentration in the ammonium carbonate solution 0.1 mol / L.

[0136] ② Add pure water, tartaric acid solution, and ammonium carbonate solution to the reaction vessel to obtain the bottom liquid, wherein the concentration of tartaric acid in the bottom liquid is 0.1 mol / L, and nitrogen gas is introduced to make the oxygen volume content 1%.

[0137] ③ Heat the reactor to 50℃, control the stirring speed at 800rpm, and simultaneously pump in metal salt solution and ammonium carbonate solution (containing ammonium sulfate). The metal salt solution (containing dilute sulfuric acid) is introduced at 8% / h of the total reactor capacity, and the ammonium carbonate solution (containing ammonium sulfate) is introduced at 30% / h of the total reactor capacity. Control the actual pH value during the reaction process, and gradually reduce the pH value from 9.70 during the nucleation period to 8.70 during the control period. The duration of the nucleation period is 2h, and the rate of pH reduction is 0.1 / h. The reaction yields nickel manganese titanium iron carbonate precursor.

[0138] ④ After the synthesis stage is completed, the material is centrifuged, washed, demagnetized, and pre-sintered at 600℃ for 5 hours to obtain the oxide precursor.

[0139] Comparative Example 4

[0140] Prepare a chemical formula ((Ni 0.40 Mn 0.33 Ti 0.15 Cu 0.12 The oxide precursor of O is prepared by the following method:

[0141] ① Raw material preparation: Dissolve nickel sulfate, manganese chloride, titanium oxysulfate, and copper sulfate pentahydrate crystals to form a mixed metal salt solution with a nickel ion concentration of 83±5 g / L, a manganese ion concentration of 64±5 g / L, a titanium ion concentration of 25±5 g / L, and a copper ion concentration of 27±5 g / L; prepare an ammonium carbonate solution with a concentration of 300±20 g / L.

[0142] ② Add pure water, tartaric acid solution, and ammonium carbonate solution to the reaction vessel to obtain the bottom liquid, wherein the concentration of tartaric acid in the bottom liquid is 0.1 mol / L, and nitrogen gas is introduced to make the oxygen volume content 0.3%.

[0143] ③ Heat the reactor to 50℃, control the stirring speed at 800rpm, and simultaneously pump in metal salt solution and ammonium carbonate solution. The metal salt solution is introduced at 8% / h of the total reactor capacity, and the ammonium carbonate solution is introduced at 20% / h of the total reactor capacity. Control the actual pH value during the reaction process, and gradually reduce the pH value from 9.20 during the nucleation period to 8.20 during the control period. The duration of the nucleation period is 2h, and the rate of pH reduction is 0.1 / h. The reaction yields nickel manganese titanium copper carbonate precursor.

[0144] ④ After the synthesis stage is completed, the material is centrifuged, washed, demagnetized, and pre-sintered at 600℃ for 5 hours to obtain the oxide precursor.

[0145] Comparative Example 5

[0146] Prepare a chemical formula (Ni 0.4 Mn 0.3 Ti 0.1 Fe 0.2 The preparation method of the carbonate precursor of CO3 is the same as steps ①-③ of Comparative Example 3, except that in step ④, the synthesis stage ends and only post-processing is performed without calcination.

[0147] Test Example 1

[0148] The carbonate precursors and oxide precursors prepared in the aforementioned embodiments and comparative examples were subjected to physicochemical data testing. Specifically:

[0149] 1. Particle size (D50) was tested using a Malvern 3000 laser particle size analyzer, referring to standard GB / T19077-2016;

[0150] 2. The test reference standard for tap density (TD) is GB / T 5162-2021, which is the determination of tap density of metal powders.

[0151] 3. Specific surface area (BET) was determined according to GB / T 19587-2017, Gas Adsorption BET Method for the determination of solid substances.

[0152] The specific results are shown in Tables 1 and 2.

[0153] Table 1: Physicochemical data of carbonate precursors prepared in each example and comparative example

[0154]

[0155]

[0156] Table 2: Physicochemical data of oxide precursors prepared in each example and comparative example

[0157] D50(μm) (D90-D10) / D50 <![CDATA[BET(m 2 / g)]]> <![CDATA[TD(g / cm 3 )]]> Example 1 4.95 0.71 42.87 1.21 Example 2 3.21 0.83 64.23 1.17 Example 3 5.42 0.93 40.26 1.23 Example 4 5.16 0.77 31.53 1.14 Comparative Example 1 5.08 0.82 27.44 1.18 Comparative Example 2 3.03 0.7 25.45 1.31 Comparative Example 3 5.45 0.88 19.56 1.32 Comparative Example 4 4.89 1.72 75.39 0.92

[0158] Test Example 2

[0159] The oxide precursor materials prepared in Examples 1-4 and Comparative Examples 1-4 were mixed with sodium carbonate and calcined in air at a temperature of 1000°C for 780 min, followed by natural cooling to prepare cathode materials. The carbonate precursor materials prepared in Example 5 and Comparative Example 5 were mixed with sodium carbonate in air and calcined at a temperature of 3°C / min to 950°C for 900 min, followed by natural cooling to prepare cathode materials. Figure 5 An exemplary SEM image of the cathode material prepared in Example 1 is shown. Figure 5 It can be seen that the positive electrode material provided by the present invention has uniform size and stable structure.

[0160] The positive electrode materials prepared in all examples and comparative examples were mixed with polyvinylidene fluoride (PVDF) and conductive carbon black in a mass ratio of 8:1:1, and added to a mixing bottle containing N-methylpyrrolidone. The mixture was stirred until homogeneous, yielding a slurry. Subsequently, the prepared slurry was uniformly coated onto aluminum foil, and the electrode sheet was dried in a vacuum drying oven at 120°C for 24 hours to obtain a positive electrode sheet. This sheet was then pressed and perforated to obtain a circular positive electrode sheet with a diameter of 12 mm. The positive electrode sheet was weighed to calculate the mass of the positive electrode material. In an argon-atmosphere protected glove box, an active material electrode was used as the positive electrode, a sodium metal sheet as the negative electrode, a CeIgard 2400 porous polyethylene membrane as the separator, and a 1 mol / L NaClO4 solution as the electrolyte. The volume ratio of ethylene carbonate:dimethyl carbonate:ethyl methyl carbonate (EC:DMC:EMC) was 1.2:0.8:1. The electrodes were assembled in the following order: positive electrode shell - sample electrode - separator - electrolyte - sodium negative electrode sheet - negative electrode shell. The assembled CR2032 coin cells were then sealed using a pressure sealing machine. After standing for 8 hours, electrochemical tests were performed using a Blue Electric system. The charge / discharge voltage range was 4.1-4.3V. The entire testing process was conducted in a 25℃ constant temperature drying cabinet.

[0161] The electrochemical performance test data are shown in Table 3.

[0162] Table 3: Electrochemical performance data of each example and comparative example

[0163] 0.1C first charge mAh / g First-time effect % 50-week cycle retention rate % Example 1 173.7 93.3 95.2 Example 2 155.1 92.8 93.2 Example 3 168.2 93.4 92.3 Example 4 171.5 93.1 94.5 Example 5 165.4 94.7 92.4 Comparative Example 1 148.2 92.7 91.4 Comparative Example 2 132.3 91.41 90.3 Comparative Example 3 142.3 92.14 88.1 Comparative Example 4 142.6 92.4 86.9 Comparative Example 5 140.5 93.3 88.1

[0164] As shown in Tables 1-3, the specific surface area of ​​the carbonate precursors in Examples 1-4 is between 150-250 m². 2 The specific surface area of ​​the oxide precursor is between 31 and 70 m² / g. 2The specific surface area of ​​the carbonate precursor in Example 5 was between 150-250 m² / g, and the capacity and cycle performance of the prepared coin cells were superior to those of Comparative Examples 1-4. 2 The corresponding coin cells prepared with a capacity between / g and / g also have higher capacity and cycle performance compared to Comparative Example 5.

[0165] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A carbonate precursor for a sodium-ion battery cathode material, characterized in that, The specific surface area of ​​the carbonate precursor is 150-250 m². 2 / g, the general chemical formula of the carbonate precursor is Ni x Mn y Ti z Me 1-x-y-z CO3, wherein 0.3≤x≤0.65, 0.3≤y≤0.65, 0.005≤z≤0.2, 0≤1-xyz≤0.395; Me includes at least one of Cu, Fe, Ca, Zn, Al, Mg, and Zr.

2. The sodium-ion battery cathode material carbonate precursor according to claim 1, characterized in that, The particle size distribution (D90-D10) / D50 of the carbonate precursor is 0.7-1.1; And / or, the tap density of the carbonate precursor is 0.8-1.3 g / cm³. 3 ; And / or, the D50 value of the carbonate precursor is 2.5-8 μm; And / or, the carbonate precursor comprises a plurality of secondary particles consisting of primary particles; optionally, the primary particles are in the form of thin flakes.

3. A sodium-ion battery cathode material oxide precursor, characterized in that, The specific surface area of ​​the oxide precursor is 31-70 m². 2 / g; the general chemical formula of the oxide precursor is Ni x Mn y Ti z Me 1-x-y-z O, where 0.3≤x≤0.65, 0.3≤y≤0.65, 0.005≤z≤0.2, 0≤1-xyz≤0.395; Me includes at least one of Cu, Fe, Ca, Zn, Al, Mg, and Zr.

4. The sodium-ion battery cathode material oxide precursor according to claim 3, characterized in that, The particle size distribution (D90-D10) / D50 of the oxide precursor is 0.7-1.0; And / or, the tap density of the oxide precursor is 0.9-1.3 g / cm³. 3 ; And / or, the D50 value of the oxide precursor is 3-8 μm.

5. A method for preparing a sodium-ion battery cathode material carbonate precursor as described in claim 1 or 2, characterized in that, The method includes: A first mixture of water, complexing agent, and pH adjuster is prepared to obtain a base solution; the conditions are controlled such that the volume content of oxygen in the base solution is <1%; The metal salt solution and the precipitant are simultaneously introduced into the reaction system formed with the base liquid for a second mixing. The flow rate of the precipitant is controlled so that the pH value of the reaction system is gradually reduced from 9.1-9.3 during the nucleation period to 8.1-8.3 during the control period, thereby obtaining the carbonate precursor. The metal salt solution includes sulfuric acid, and the precipitant includes ammonium sulfate.

6. The preparation method according to claim 5, characterized in that, The method satisfies at least one of the following conditions: A. The metal salt solution includes Ni, Mn, and Ti elements; Optionally, the metal salt solution further includes at least one of the elements Cu, Fe, Ca, Zn, Al, Mg, and Zr; B. The complexing agent is selected from at least one of tartaric acid, citric acid, oxalic acid, ammonium sulfate, and ammonia water; C. The pH adjuster and the precipitant are each independently selected from at least one of ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate; D. In the underlying solution, the concentration of the complexing agent is 0.01-0.1 mol / L; E. The molar ratio of the metal salt solution to the precipitant is 1:1.2-1.5; F. The metal salt solution includes at least one of the following: a hydrochloride solution, a sulfate solution, and a nitrate solution of the metal element; the sum of the concentrations of the metal elements in the metal salt solution is 3-5 mol / L; G. The concentration of the sulfuric acid in the metal salt solution is 0.005-0.01 mol / L; H. The concentration of ammonium sulfate in the precipitant is 0.05-0.1 mol / L; I. The second mixing is carried out in a reactor, wherein the flow rate of the metal salt solution introduced into the reactor is 6% to 10% of the total capacity of the reactor; J. The duration of the nucleation period is 1.5-2.5 h, and the rate of decrease of the gradually decreasing pH value is 0.1-0.3 / h; K. The conditions for the second mixing are: temperature 30-60℃; stirring speed 600-900rpm.

7. A method for preparing a sodium-ion battery cathode material oxide precursor as described in claim 3 or 4, characterized in that, The method includes: Provides the carbonate precursor according to claim 1 or 2, or the carbonate precursor prepared by the method for preparing the carbonate precursor according to claim 5 or 6. The carbonate precursor is sintered to obtain the oxide precursor. Optionally, the sintering temperature is 550-650℃, and the sintering time is 4-6 hours.

8. A sodium-ion battery cathode material, characterized in that, The raw materials for the sodium-ion battery cathode material include the sodium-ion battery cathode material carbonate precursor according to any one of claims 1-2, or the sodium-ion battery cathode material oxide precursor according to any one of claims 3-4.

9. A sodium-ion battery, characterized in that, Including the sodium-ion battery cathode material as described in claim 8.

10. An electrical-related device, characterized in that, Including the sodium-ion battery as described in claim 9.

Images