Anion-cation dual-doped battery precursor, positive electrode material, preparation method and use

Abstract

The present application relates to an anion-cation dual-doped battery precursor, a positive electrode material, a preparation method and a use. The preparation method comprises the following steps: mixing a precipitant solution, a complexing agent solution, a boron source solution and a mixed salt solution, subjecting the resulting mixture to a coprecipitation reaction until a target particle size is reached, and performing solid-liquid separation, washing and drying, so as to obtain the anion-cation dual-doped battery precursor. In the present application, by means of dual doping with molybdenum cations and boron anions, the electrochemical performance of the obtained anion-cation dual-doped battery precursor is improved; moreover, by means of a mode of feeding the mixed salt solution and the boron source solution, redundant procedures are reduced, the preparation cost is reduced, and the content of Mo and B can be stabilized, thereby achieving uniform doping with Mo and B.

Description

Anion-cation dual-doped battery precursor, positive electrode material, preparation method and application Technical Field

[0001] The present application belongs to the field of battery technology and relates to a battery precursor, and in particular to an anion-cation dual-doped battery precursor, a positive electrode material, a preparation method and an application. Background Art

[0002] In recent years, the widespread adoption of lithium-ion batteries in electric vehicles has dramatically increased demand for lithium resources. However, lithium reserves in the Earth's crust are scarce and geographically unevenly distributed, leading to rising costs for lithium-ion batteries and limiting their application in large-scale power storage.

[0003] Sodium-ion batteries share a similar charge and discharge mechanism to lithium-ion batteries, and sodium resources are abundant and widely distributed. Therefore, the development of sodium-ion battery technology has a positive impact on large-scale power storage systems. While reducing costs, sodium-ion batteries also offer high specific energy density, excellent energy conversion efficiency, a long charge and discharge cycle life, and superior safety performance, providing an opportunity to gradually replace lead-acid batteries.

[0004] However, existing sodium ion layered oxides have problems maintaining the stability of their layered structures under high-voltage charging conditions and exhibiting sodium deficiency in their original state. Therefore, it is necessary to provide a precursor, cathode material, preparation method, and application of an anion-cation dual-doped battery with excellent electrochemical properties, such as cycling performance and rate capability.

[0005] Summary of the Invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] The purpose of the present application is to provide an anion-cation dual-doped battery precursor, a positive electrode material, a preparation method and an application. The preparation method can reduce redundant steps and reduce preparation costs. At the same time, it can stabilize the content of Mo and B elements and achieve uniform doping of Mo and B elements, so that the obtained anion-cation dual-doped battery precursor has excellent electrochemical properties.

[0008] To achieve this goal, this application adopts the following technical solutions:

[0009] In a first aspect, the present application provides a method for preparing an anion-cation dual-doped battery precursor, the preparation method comprising the following steps:

[0010] A mixed precipitant solution, a complexing agent solution, a boron source solution, and a mixed salt solution are subjected to a coprecipitation reaction until the target particle size is reached, followed by solid-liquid separation, washing, and drying to obtain the anion-cation dual-doped battery precursor.

[0011] The metal ions in the mixed salt solution include nickel ions, copper ions, ferrous ions, manganese ions, and molybdenum ions; the molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is a:b:c:d, where 0 < a ≤ 0.4, 0 < b ≤ 0.2, 0 < c ≤ 0.3, 0.3 ≤ d ≤ 0.45, and a + b + c + d = 1.

[0012] The preparation method provided in this application adopts the feeding method of the mixed salt solution and the boron source solution, reducing redundant processes, lowering the preparation cost, and at the same time being able to stabilize the contents of Mo and B elements, achieving the uniform doping of Mo and B elements; among them, the role of the Mo element is to stabilize the overall framework in the structure, widen the layer spacing, and facilitate the insertion and extraction of sodium ions, and the role of the B element is to combine with oxygen to form strong B-O bonds, stabilize the lattice oxygen, and reduce the possibility of structural deformation. Through the cooperation of Mo and B elements, the electrochemical performance of the obtained anion-cation dual-doped battery precursor is improved.

[0013] In one embodiment, the total concentration of nickel ions, copper ions, ferrous ions, and manganese ions in the mixed salt solution is 1.5 - 2 mol / L.

[0014] In one embodiment, the concentration of molybdenum ions in the mixed salt solution is 2 - 17 mmol / L.

[0015] In one embodiment, the metal salts in the mixed salt solution include nickel salts, copper salts, ferrous salts, manganese salts, and molybdates.

[0016] In one embodiment, the nickel salt includes any one or a combination of at least two of nickel sulfate, nickel nitrate, or nickel chloride.

[0017] In one embodiment, the copper salt includes any one or a combination of at least two of copper sulfate, copper nitrate, or copper chloride.

[0018] In one embodiment, the ferrous salt includes any one or a combination of at least two of ferrous sulfate, ferrous nitrate, or ferrous chloride.

[0019] In one embodiment, the manganese salt includes any one or a combination of at least two of manganese sulfate, manganese nitrate, or manganese dichloride.

[0020] In one embodiment, the molybdate includes sodium molybdate and / or ammonium molybdate.

[0021] In one embodiment, the boron source in the boron source solution includes any one of sodium metaborate, boric acid, ammonium metaborate or sodium tetraborate, or a combination of at least two thereof.

[0022] In one embodiment, the boron concentration in the boron source solution is 0.45-0.5 mol / L.

[0023] In one embodiment, the flow rate of the mixed salt solution is 250-400 mL / h.

[0024] In one embodiment, the flow rate of the boron source solution is 3-8 mL / h.

[0025] In one embodiment, the flow rate of the complexing agent solution is 18-24 mL / h.

[0026] In one embodiment, the coprecipitation reaction temperature is 40-70°C.

[0027] In one embodiment, the pH value of the coprecipitation reaction is 9.5-10.5.

[0028] In one embodiment, the target particle size of the coprecipitation reaction is a particle size D50 of 4.8-5.2 μm.

[0029] In one embodiment, the coprecipitation reaction is carried out under stirring, and the stirring rate of the stirring is 250-400 rpm.

[0030] In one embodiment, the drying temperature is 100-170°C.

[0031] In a second aspect, the present application provides an anion-cation dual-doped battery precursor, which is prepared by the preparation method described in the first aspect.

[0032] In a third aspect, the present application provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0033] The sodium source is mixed with the anion-cation dual-doped battery precursor described in the second aspect, and calcined to obtain the positive electrode material.

[0034] In one embodiment, the calcination temperature is 860-920° C. and the calcination time is 18-22 hours.

[0035] In a fourth aspect, the present application provides a positive electrode material, which is prepared by the preparation method described in the third aspect.

[0036] In a fifth aspect, the present application provides a battery, which includes the anion-cation dual-doped battery precursor described in the second aspect, or includes the positive electrode material described in the fourth aspect.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] The preparation method provided by the present application adopts the feeding method of a mixed salt solution and a boron source solution, reduces redundant processes, lowers the preparation cost, and can stabilize the contents of Mo and B elements at the same time, achieving the uniform doping of Mo and B elements; among them, the role of Mo element is to stabilize the overall framework in the structure, widen the layer spacing, and facilitate the insertion and extraction of sodium ions, and the role of B element is to combine with oxygen to form strong B-O bonds, stabilize the lattice oxygen, and reduce the possibility of structural deformation. Through the cooperation of Mo and B elements, the electrochemical performance of the obtained anion-cation double-doped battery precursor is improved.

[0039] Other aspects can be understood after reading and understanding the drawings and the detailed description. Description of the Drawings

[0040] The drawings are used to provide a further understanding of the technical solutions herein and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solutions herein and do not constitute a limitation to the technical solutions herein.

[0041] FIG. 1 is a SEM image of the anion-cation double-doped battery precursor obtained in Example 1. Detailed Embodiments

[0042] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present application and should not be regarded as specific limitations to the present application.

[0043] A certain embodiment of the present application provides a preparation method for an anion-cation double-doped battery precursor, and the preparation method includes the following steps:

[0044] Mix a precipitating agent solution, a complexing agent solution, a boron source solution, and a mixed salt solution, carry out a coprecipitation reaction until the target particle size, and obtain the anion-cation double-doped battery precursor through solid-liquid separation, washing, and drying;

[0045] The metal ions in the mixed salt solution include nickel ions, copper ions, ferrous ions, manganese ions, and molybdenum ions; the molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is a:b:c:d, 0 < a ≤ 0.4, 0 < b ≤ 0.2, 0 < c ≤ 0.3, 0.3 ≤ d ≤ 0.45, and a + b + c + d = 1.

[0046] The preparation method provided by this application adopts the feeding mode of a mixed salt solution and a boron source solution, reducing redundant processes, lowering the preparation cost, and being able to stabilize the contents of Mo and B elements, achieving the uniform doping of Mo and B elements. Among them, the role of the Mo element is to stabilize the overall framework in the structure, widen the layer spacing, and facilitate the insertion and extraction of sodium ions. The role of the B element is to combine with oxygen to form strong B-O bonds, stabilize lattice oxygen, and reduce the possibility of structural deformation. Through the cooperation of Mo and B elements, the electrochemical performance of the obtained cation and anion dual-doped battery precursor is improved.

[0047] In the mixed salt solution of this application, the molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is a:b:c:d. The value range of a satisfies 0 < a ≤ 0.4. For example, it can be 0.05, 0.1, 0.2, 0.3, or 0.4, but is not limited to the listed values. Other unlisted values within the value range are equally applicable.

[0048] The value range of b satisfies 0 < b ≤ 0.2. For example, it can be 0.05, 0.1, 0.15, or 0.2, but is not limited to the listed values. Other unlisted values within the value range are equally applicable.

[0049] The value range of c is 0 < c ≤ 0.3. For example, it can be 0.05, 0.1, 0.15, 0.2, 0.25, or 0.3, but is not limited to the listed values. Other unlisted values within the value range are equally applicable.

[0050] The value range of d is 0.3 ≤ d ≤ 0.45. For example, it can be 0.3, 0.32, 0.35, 0.4, 0.42, or 0.45, but is not limited to the listed values. Other unlisted values within the value range are equally applicable.

[0051] In some embodiments, the total concentration of nickel ions, copper ions, ferrous ions, and manganese ions in the mixed salt solution is 1.5 - 2 mol / L. For example, it can be 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, or 2 mol / L, but is not limited to the listed values. Other unlisted values within the value range are equally applicable.

[0052] In some embodiments, the concentration of molybdenum ions in the mixed salt solution is 2 - 17 mmol / L. For example, it can be 2 mmol / L, 4 mmol / L, 5 mmol / L, 8 mmol / L, 10 mmol / L, 12 mmol / L, 15 mmol / L, or 17 mmol / L, but is not limited to the listed values. Other unlisted values within the value range are equally applicable.

[0053] When the molybdenum ion concentration in the mixed salt solution is less than 2mmol / L, the molybdenum content in the structure is too low to support the material structure, and the doping effect is not obvious; when the molybdenum ion concentration in the mixed salt solution exceeds 17mmol / L, the molybdenum content in the structure is too high, which destroys the original structure of the material and causes the degradation of material performance.

[0054] The concentration of molybdenum ions described in this application refers to the concentration of molybdate ions in the mixed salt solution.

[0055] In certain embodiments, the metal salts in the mixed salt solution include nickel salts, copper salts, ferrous salts, manganese salts, and molybdates.

[0056] In certain embodiments, the nickel salt includes any one or a combination of at least two of nickel sulfate, nickel nitrate, or nickel chloride. Typical but non-limiting combinations include a combination of nickel sulfate and nickel nitrate, a combination of nickel nitrate and nickel chloride, a combination of nickel sulfate and nickel chloride, or a combination of nickel sulfate, nickel nitrate, and nickel chloride.

[0057] In certain embodiments, the copper salt includes any one or a combination of at least two of copper sulfate, copper nitrate, or copper chloride. Typical but non-limiting combinations include a combination of copper sulfate and copper nitrate, a combination of copper nitrate and copper chloride, a combination of copper sulfate and copper chloride, or a combination of copper sulfate, copper nitrate, and copper chloride.

[0058] In certain embodiments, the ferrous salt includes any one or a combination of at least two of ferrous sulfate, ferrous nitrate or ferrous chloride. Typical but non-limiting combinations include a combination of ferrous sulfate and ferrous nitrate, a combination of ferrous nitrate and ferrous chloride, a combination of ferrous sulfate and ferrous chloride, or a combination of ferrous sulfate, ferrous nitrate and ferrous chloride.

[0059] In certain embodiments, the manganese salt includes any one or a combination of at least two of manganese sulfate, manganese nitrate, or manganese dichloride. Typical but non-limiting combinations include a combination of manganese sulfate and manganese nitrate, a combination of manganese nitrate and manganese chloride, a combination of manganese sulfate and manganese chloride, or a combination of manganese sulfate, manganese nitrate, and manganese chloride.

[0060] In certain embodiments, the molybdate salt includes sodium molybdate and / or ammonium molybdate.

[0061] In certain embodiments, the boron source in the boron source solution includes any one or a combination of at least two of sodium metaborate, boric acid, ammonium metaborate or sodium tetraborate. Typical but non-limiting combinations include a combination of sodium metaborate and ammonium metaborate, a combination of boric acid and ammonium metaborate, a combination of boric acid and sodium tetraborate, a combination of sodium metaborate, boric acid and ammonium metaborate, or a combination of sodium metaborate, boric acid, ammonium metaborate and sodium tetraborate.

[0062] In some embodiments, the boron concentration in the boron source solution is 0.45-0.5 mol / L, for example, it can be 0.45 mol / L, 0.46 mol / L, 0.48 mol / L, 0.49 mol / L or 0.5 mol / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0063] The boron concentration in the boron source solution described in this application refers to the concentration calculated based on the molar amount of the boron element.

[0064] When the boron concentration in the boron source solution is less than 0.45 mol / L, the boron content in the structure is too low, the combination with lattice oxygen is limited, and the doping effect is not obvious; when the boron concentration in the boron source solution exceeds 0.5 mol / L, the boron content in the structure is too high, which destroys the original structure of the material and causes performance degradation.

[0065] In certain embodiments, the flow rate of the mixed salt solution is 250-400 mL / h, for example, 250 mL / h, 270 mL / h, 280 mL / h, 300 mL / h, 320 mL / h, 350 mL / h, or 400 mL / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0066] In some embodiments, the flow rate of the boron source solution is 3-8 mL / h, for example, 3 mL / h, 4 mL / h, 5 mL / h, 6 mL / h or 8 mL / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0067] In some embodiments, the flow rate of the complexing agent solution is 18-24 mL / h, for example, 18 mL / h, 20 mL / h, 21 mL / h, 22 mL / h or 24 mL / h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0068] In the present application, the complexing agent solution includes aqueous ammonia with a concentration of 4.5-5 mol / L, for example, it can be 4.5 mol / L, 4.6 mol / L, 4.8 mol / L, 4.9 mol / L or 5 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0069] The present application does not impose too many restrictions on the specific composition and specific concentration of the precipitant solution, as long as the pH value of the coprecipitation reaction meets the process requirements. Exemplarily, the coprecipitation solution is a sodium hydroxide solution with a concentration of 6-10 mol / L, for example, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L or 10 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0070] In certain embodiments, the temperature of the coprecipitation reaction is 40-70°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or 70°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0071] In certain embodiments, the pH value of the coprecipitation reaction is 9.5-10.5, for example, 9.5, 9.8, 10, 10.2 or 10.5, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0072] In certain embodiments, the target particle size of the coprecipitation reaction is a particle size D50 of 4.8-5.2 μm, for example, 4.8 μm, 4.9 μm, 5.0 μm, 5.1 μm or 5.2 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0073] In certain embodiments, the coprecipitation reaction is carried out under stirring conditions, and the stirring rate of the stirring is 250-400 rpm, for example, it can be 250 rpm, 280 rpm, 300 rpm, 320 rpm, 350 rpm, 380 rpm or 400 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0074] In this application, the solid-liquid separation and washing methods are conventional methods in the art, as long as they can achieve the solid-liquid separation and washing effects. For example, the solid-liquid separation method described in this application includes filtration using a Buchner funnel; the washing methods described include but are not limited to washing with hot water and liquid caustic soda.

[0075] In some embodiments, the drying temperature is 100-170°C, for example, 100°C, 120°C, 140°C, 150°C or 170°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0076] A certain embodiment of the present application provides an anion-cation dual-doped battery precursor, which is prepared by the preparation method in certain embodiments.

[0077] A certain embodiment of the present application provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0078] The positive electrode material is obtained by mixing a sodium source with an anion-cation dual-doped battery precursor in certain embodiments and calcining the mixture.

[0079] In certain embodiments, the sodium source comprises sodium carbonate and / or sodium hydroxide.

[0080] In certain embodiments, in order to compensate for the loss of sodium source during calcination, the molar ratio of Na in the sodium source to the anion-cation dual-doped battery precursor is (1-1.05):1, for example, it can be 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1 or 1.05:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0081] In certain embodiments, the calcination temperature is 860-920° C., and the calcination time is 18-22 hours.

[0082] The calcination temperature in the present application is 860-920°C, for example, it can be 860°C, 880°C, 900°C, 910°C or 920°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0083] The calcination time in the present application is 18-22 hours, for example, 18 hours, 19 hours, 20 hours, 21 hours or 22 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0084] A certain embodiment of the present application provides a positive electrode material, which is prepared by the preparation method in certain embodiments.

[0085] A certain embodiment of the present application provides a battery, which includes the anion-cation dual-doped battery precursor in certain embodiments, or includes the positive electrode material in certain embodiments.

[0086] Example 1

[0087] This embodiment provides a method for preparing an anion-cation dual-doped battery precursor, the preparation method comprising the following steps:

[0088] 8 mol / L sodium hydroxide solution, 4.7 mol / L ammonia water, boron source solution and mixed salt solution were added to the reactor in parallel, and a co-precipitation reaction was carried out under stirring at 300 rpm until the target particle size D50 was 5 μm. The precursor was filtered, washed with hot water and liquid alkali, and dried at 130° C. to obtain the anion-cation dual-doped battery precursor.

[0089] The metal salts in the mixed salt solution include nickel sulfate, copper sulfate, ferrous sulfate, manganese sulfate, and sodium molybdate. The total concentration of nickel ions, copper ions, ferrous ions, and manganese ions is 1.73 mol / L, and the concentration of molybdenum ions is 5 mmol / L. The molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is 4:1:1:4.

[0090] The boron source solution is a sodium metaborate solution, wherein the boron concentration is 0.4625 mol / L;

[0091] The flow rate of the mixed salt solution is 320 mL / h, the flow rate of the ammonia water is 20 mL / h, and the flow rate of the boron source solution is 5.1 mL / h; the temperature of the coprecipitation reaction is 50° C., and the pH value is 10.

[0092] The SEM image of the anion-cation dual-doped battery precursor obtained in this example is shown in FIG1 .

[0093] Example 2

[0094] This embodiment provides a method for preparing an anion-cation dual-doped battery precursor, the preparation method comprising the following steps:

[0095] 6 mol / L sodium hydroxide solution, 4.5 mol / L ammonia water, boron source solution and mixed salt solution were added to the reactor in parallel, and a co-precipitation reaction was carried out under stirring at 250 rpm until the target particle size D50 was 4.8 μm. The precursor was filtered, washed with hot water and liquid alkali, and dried at 100° C. to obtain the anion-cation dual-doped battery precursor.

[0096] The metal salts in the mixed salt solution include nickel sulfate, copper sulfate, ferrous sulfate, manganese sulfate, and sodium molybdate. The total concentration of nickel ions, copper ions, ferrous ions, and manganese ions is 1.5 mol / L, and the concentration of molybdenum ions is 2 mmol / L. The molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is 4:1:1:4.

[0097] The boron source solution is an ammonia metaborate solution, wherein the boron concentration is 0.45 mol / L;

[0098] The flow rate of the mixed salt solution is 250 mL / h, the flow rate of the ammonia water is 18 mL / h, and the flow rate of the boron source solution is 3 mL / h; the temperature of the coprecipitation reaction is 40° C., and the pH value is 9.5.

[0099] Example 3

[0100] This embodiment provides a method for preparing an anion-cation dual-doped battery precursor, the preparation method comprising the following steps:

[0101] A 10 mol / L sodium hydroxide solution, a 5 mol / L ammonia solution, a boron source solution, and a mixed salt solution were added concurrently to a reactor, and a coprecipitation reaction was performed under stirring at 400 rpm until the target particle size D50 was 5.2 μm. The precursor was filtered, washed with hot water and liquid alkali, and dried at 170° C. to obtain the anion-cation dual-doped battery precursor.

[0102] The metal salts in the mixed salt solution include nickel sulfate, copper sulfate, ferrous sulfate, manganese sulfate, and sodium molybdate. The total concentration of nickel ions, copper ions, ferrous ions, and manganese ions is 2 mol / L, and the concentration of molybdenum ions is 17 mmol / L. The molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is 4:1:1:4.

[0103] The boron source solution is a sodium tetraborate solution, wherein the boron concentration is 0.5 mol / L;

[0104] The flow rate of the mixed salt solution is 400 mL / h, the flow rate of the ammonia water is 24 mL / h, and the flow rate of the boron source solution is 8 mL / h; the temperature of the coprecipitation reaction is 70° C., and the pH value is 10.5.

[0105] Example 4

[0106] This embodiment provides a method for preparing an anion-cation dual-doped battery precursor, which is the same as Example 1 except that the concentration of molybdenum ions in the mixed salt solution is 1 mmol / L.

[0107] Example 5

[0108] This embodiment provides a method for preparing an anion-cation dual-doped battery precursor, which is the same as Example 1 except that the concentration of molybdenum ions in the mixed salt solution is 20 mmol / L.

[0109] Example 6

[0110] This embodiment provides a method for preparing an anion-cation dual-doped battery precursor, which is the same as that of Example 1 except that the boron concentration in the boron source solution is 0.42 mol / L.

[0111] Example 7

[0112] This embodiment provides a method for preparing an anion-cation dual-doped battery precursor, which is the same as that of Example 1 except that the boron concentration in the boron source solution is 0.54 mol / L.

[0113] Comparative Example 1

[0114] This comparative example provides a method for preparing a battery precursor, which comprises the following steps:

[0115] 8 mol / L sodium hydroxide solution, 4.7 mol / L ammonia water, boron source solution and mixed salt solution were added to the reactor in parallel, and a co-precipitation reaction was carried out under stirring at 300 rpm until the target particle size D50 was 5 μm. The precursor was filtered, washed with hot water and liquid alkali, and dried at 130° C. to obtain the anion-cation dual-doped battery precursor.

[0116] The metal salts in the mixed salt solution include nickel sulfate, copper sulfate, ferrous sulfate, and manganese sulfate. The total concentration of nickel ions, copper ions, ferrous ions, and manganese ions is 1.73 mol / L. The molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is 4:1:1:4.

[0117] The boron source solution is a sodium metaborate solution, wherein the boron concentration is 0.4625 mol / L;

[0118] The flow rate of the mixed salt solution is 320 mL / h, the flow rate of the ammonia water is 20 mL / h, and the flow rate of the boron source solution is 5.1 mL / h; the temperature of the coprecipitation reaction is 50° C., and the pH value is 10.

[0119] Comparative Example 2

[0120] This embodiment provides a method for preparing a battery precursor, the method comprising the following steps:

[0121] 8 mol / L sodium hydroxide solution, 4.7 mol / L ammonia water, and a mixed salt solution were added concurrently to the reactor, and a coprecipitation reaction was carried out under stirring at 300 rpm until the target particle size D50 was 5 μm. The precursor was filtered, washed with hot water and liquid alkali, and dried at 130° C. to obtain the anion-cation dual-doped battery precursor.

[0122] The metal salts in the mixed salt solution include nickel sulfate, copper sulfate, ferrous sulfate, manganese sulfate, and sodium molybdate. The total concentration of nickel ions, copper ions, ferrous ions, and manganese ions is 1.73 mol / L, and the concentration of molybdenum ions is 5 mmol / L. The molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is 4:1:1:4.

[0123] The flow rate of the mixed salt solution is 320 mL / h, the flow rate of the ammonia water is 20 mL / h, and the flow rate of the boron source solution is 5.1 mL / h; the temperature of the coprecipitation reaction is 50° C., and the pH value is 10.

[0124] Application Example 1

[0125] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0126] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 1 and calcined at 890° C. for 20 h to obtain a positive electrode material.

[0127] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0128] Application Example 2

[0129] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0130] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 2, and calcined at 890° C. for 20 h to obtain a positive electrode material.

[0131] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0132] Application Example 3

[0133] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0134] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 3 and calcined at 890° C. for 20 h to obtain a positive electrode material.

[0135] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0136] Application Example 4

[0137] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0138] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 4, and calcined at 890° C. for 20 h to obtain a positive electrode material.

[0139] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0140] Application Example 5

[0141] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0142] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 5, and calcined at 890° C. for 20 h to obtain a positive electrode material.

[0143] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0144] Application Example 6

[0145] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0146] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 6, and calcined at 890° C. for 20 h to obtain a positive electrode material.

[0147] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0148] Application Example 7

[0149] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0150] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 7, and calcined at 890° C. for 20 h to obtain a positive electrode material.

[0151] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0152] Application Example 8

[0153] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0154] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 1 and calcined at 860° C. for 22 h to obtain a positive electrode material.

[0155] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0156] Application Example 9

[0157] This application example provides a method for preparing a positive electrode material, the preparation method comprising the following steps:

[0158] Sodium carbonate was mixed with the anion-cation dual-doped battery precursor provided in Example 1 and calcined at 920° C. for 18 h to obtain a positive electrode material.

[0159] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0160] Comparative Application Example 1

[0161] This comparative application example provides a method for preparing a positive electrode material, which comprises the following steps: mixing sodium carbonate with the battery precursor provided in Comparative Example 1, and calcining the mixture at 890° C. for 20 hours to obtain a positive electrode material.

[0162] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0163] Comparative Application Example 2

[0164] This comparative application example provides a method for preparing a positive electrode material, which comprises the following steps: mixing sodium carbonate with the battery precursor provided in Comparative Example 2, and calcining the mixture at 890° C. for 20 hours to obtain a positive electrode material.

[0165] The molar ratio of sodium in sodium carbonate to anion-cation dual-doped battery precursor is 1.03:1.

[0166] Performance Characterization

[0167] The positive electrode materials provided in Application Examples 1-9 and Comparative Application Examples 1-3 were prepared into button batteries:

[0168] The positive electrode material, conductive carbon black (Super P), and binder polyvinylidene fluoride (PVDF) are thoroughly stirred and mixed in an appropriate amount of N-methylpyrrolidone (NMP) in a weight ratio of 90:5:5 to form a uniform positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector aluminum foil, and after drying, it is punched into a disc with a diameter of 14 mm as the positive electrode sheet; a metal sodium sheet is used as the negative electrode sheet; a Celgard2400 model separator is used as the separator; the electrolyte is 1 mol / L NaClO4 (the solvent is ethylene carbonate and diethyl carbonate in a volume ratio of 1:1); the positive electrode sheet, separator, and negative electrode sheet are stacked in order, the electrolyte is added and the battery is sealed to obtain a button battery.

[0169] At 25°C and 0.1MPa, the button battery was charged at a constant current rate of 0.1C to a voltage of 4.05V, allowed to stand for 5 minutes, and then discharged at a constant current rate of 0.1C to a voltage of 2.5V, allowed to stand for 5 minutes. The discharge capacity was recorded as the first-cycle discharge specific capacity. According to the above method, 100 cycles of charge and discharge tests were performed to detect the cycle capacity retention rate.

[0170] Table 1

[0171] In summary, the preparation method provided in the present application adopts a mixed salt solution and boron source solution feeding method, which reduces redundant processes and reduces preparation costs. At the same time, it can stabilize the content of Mo and B elements and achieve uniform doping of Mo and B elements; wherein, the role of the Mo element is to stabilize the overall framework in the structure, widen the interlayer spacing, and facilitate the deintercalation of sodium ions. The role of the B element is to combine with oxygen to form a strong BO bond, stabilize the lattice oxygen, and reduce the possibility of structural deformation. Through the synergy of Mo and B elements, the electrochemical performance of the obtained anion-cation dual-doped battery precursor is improved.

[0172] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art should understand that any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application fall within the protection scope and disclosure scope of the present application.

Claims

1. A preparation method of a cation-anion dual-doped battery precursor, comprising the following steps: Mix a precipitant solution, a complexing agent solution, a boron source solution, and a mixed salt solution, carry out a coprecipitation reaction until the target particle size, and obtain the cation-anion dual-doped battery precursor through solid-liquid separation, washing, and drying; The metal ions in the mixed salt solution include nickel ions, copper ions, ferrous ions, manganese ions, and molybdenum ions; Among them, the molar ratio of nickel ions, copper ions, ferrous ions, and manganese ions is a:b:c:d, 0 < a ≤ 0.4, 0 < b ≤ 0.2, 0 < c ≤ 0.3, 0.3 ≤ d ≤ 0.45, and a + b + c + d = 1.

2. The preparation method according to claim 1, wherein, The total concentration of nickel ions, copper ions, ferrous ions, and manganese ions in the mixed salt solution is 1.5 - 2 mol / L; Optionally, the concentration of molybdenum ions in the mixed salt solution is 2 - 17 mmol / L.

3. The preparation method according to claim 1 or 2, wherein, The metal salts in the mixed salt solution include nickel salts, copper salts, ferrous salts, manganese salts, and molybdates; Optionally, the nickel salt includes any one or a combination of at least two of nickel sulfate, nickel nitrate, or nickel chloride; Optionally, the copper salt includes any one or a combination of at least two of copper sulfate, copper nitrate, or copper chloride; Optionally, the ferrous salt includes any one or a combination of at least two of ferrous sulfate, ferrous nitrate, or ferrous chloride; Optionally, the manganese salt includes any one or a combination of at least two of manganese sulfate, manganese nitrate, or manganese dichloride; Optionally, the molybdate includes sodium molybdate and / or ammonium molybdate.

4. The preparation method according to any one of claims 1 - 3, wherein, The boron source in the boron source solution includes any one or a combination of at least two of sodium metaborate, boric acid, ammonium metaborate, or sodium tetraborate; Optionally, the concentration of boron in the boron source solution is 0.45 - 0.5 mol / L.

5. The preparation method according to any one of claims 1 - 4, wherein, The flow rate of the mixed salt solution is 250 - 400 mL / h; Optionally, the flow rate of the boron source solution is 3 - 8 mL / h; Optionally, the flow rate of the complexing agent solution is 18 - 24 mL / h; Optionally, the temperature of the coprecipitation reaction is 40 - 70 °C; Optionally, the pH value of the coprecipitation reaction is 9.5 - 10.5; Optionally, the target particle size of the coprecipitation reaction is that the particle size D50 reaches 4.8 - 5.2 μm.

6. The preparation method according to claim 5, wherein, The coprecipitation reaction is carried out under stirring, and the stirring rate of the stirring is 250 - 400 rpm; Optionally, the temperature of the drying is 100 - 170 °C.

7. A cation-anion dual-doped battery precursor prepared by the preparation method according to any one of claims 1 - 6.

8. A preparation method of a cathode material, comprising the following steps: Mix a sodium source and the cation-anion dual-doped battery precursor according to claim 7, and calcine to obtain the cathode material.

9. A cathode material prepared by the preparation method according to claim 8.

10. A battery comprising the anion-cation dual-doped battery precursor according to claim 7, or comprising the positive electrode material according to claim 9.

Images