CN114572958B - Preparation method of fluorine-containing polyanion-type positive electrode material and fluorine-containing polyanion-type positive electrode material - Google Patents

Preparation method of fluorine-containing polyanion-type positive electrode material and fluorine-containing polyanion-type positive electrode material Download PDF

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CN114572958B
CN114572958B CN202210210406.7A CN202210210406A CN114572958B CN 114572958 B CN114572958 B CN 114572958B CN 202210210406 A CN202210210406 A CN 202210210406A CN 114572958 B CN114572958 B CN 114572958B
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potassium
sodium
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CN114572958A (en
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刘继磊
范长岭
符庆丰
胡壮
张维华
陈雨晴
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Hunan University
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Abstract

The invention provides a preparation method of a fluorine-containing polyanion-type anode material, belonging to the technology of anode materials of alkali metal ion batteriesThe field of surgery. The chemical general formula of the fluorine polyanion type cathode material is AVPO 4 F or A 3 V 2 (PO 4 ) 2 F 3 Wherein A is any one of alkali metal elements, particularly Li, na and K, and the preparation method comprises the following steps: adding a template agent and a fluorine-containing additive into the spraying mother liquor, granulating by adopting a spray drying technology, and finally sintering at a high temperature in a solid phase to obtain the catalyst. The preparation method provided by the invention has simple steps, and the obtained product is regular spherical, has large specific surface area, high purity and good electrochemical performance.

Description

Preparation method of fluorine-containing polyanion-type positive electrode material and fluorine-containing polyanion-type positive electrode material
Technical Field
The invention belongs to the technical field of anode materials of alkali metal ion batteries, and particularly relates to a preparation method of a fluorine-containing polyanionic anode material and the fluorine-containing polyanionic anode material.
Background
Under the background that the energy crisis and the environmental problem are increasingly prominent, governments of various countries are continuously encouraged to devote on the development of new energy. Rechargeable alkali metal ion batteries (lithium ion batteries, sodium ion batteries, potassium ion batteries, etc.) have the advantages of high energy density and long cycle life, and thus become the power source of power batteries and various energy storage batteries.
The polyanion compound is a general name of a series of compounds containing tetrahedral or octahedral anion structural units, and the structural units are connected into a three-dimensional network structure through strong covalent bonds and form more highly coordinated gaps occupied by other metal ions, so that the polyanion compound cathode material has a different crystalline phase structure from other cathode materials and various outstanding properties (such as good rate, stable cycle and the like) determined by the structure. Wherein, AVPO of the fluorine-containing polyanion material 4 F and A 3 V 2 (PO 4 ) 2 F 3 (wherein A is an alkali metal element: li, na)K) are considered to be potential alkali metal battery positive electrode materials for large-scale commercial applications.
The following methods are generally used for preparing such polyanionic positive electrode materials: two-step carbothermic, sol-gel and solvothermal methods. U.S. published patent No. US 2019/0280299A1 proposes the synthesis of KVPO containing an impurity phase by carbothermic reduction 4 F, the relative purity of the synthesized material is not high. And the method firstly synthesizes the intermediate phase VPO 4 Then, the catalyst is mixed with KF for calcination, and the synthesis process is complex. Chinese patent CN108258219A discloses a preparation method of potassium-ion battery anode material vanadium potassium fluorophosphate/carbon, wherein reaction raw materials are mixed with polyethylene glycol solution to form viscous solution, the mixture is dried and then roasted under the condition of high-temperature inert atmosphere to synthesize K 3 V 2 (PO 4 ) 2 F 3 a/C composite material. The method makes full mixing of precursor raw materials by utilizing the characteristic of strong solubility of polyethylene glycol solution to avoid K 3 V 2 (PO 4 ) 2 F 3 Fluorine is lost in the synthesis process, but fluorine loss at high temperature cannot be avoided, so that the product purity is reduced. Chinese patent CN111099571A discloses a method for preparing potassium vanadium fluorophosphate, and high-purity KVPO is prepared by adopting a solvothermal method 4 F, but the solvothermal method has higher cost and low yield, and is not suitable for large-scale production. Chinese patent CN108365199A discloses a carbon-coated vanadium potassium fluorophosphate carbon nanotube composite material (K) 3 V 2 O 2 (PO 4 ) 2 F @ C/CNT or K 3 V 2 (PO 4 ) 2 F 3 @ C/CNT) to obtain the carbon-coated vanadium potassium fluorophosphate carbon nanotube composite material by a spray drying mode, wherein KF is only used as a fluorine source and a potassium source, and fluorine is lost in a heat treatment process, so that a heterogeneous phase still exists in a product, and the electrochemical performance is poor. In addition, the requirement of industrial application is difficult to meet due to the lack of a template agent and the inability to granulate.
Disclosure of Invention
The technical problem underlying the present invention is to overcome the disadvantages and drawbacks mentioned in the background of the invention bySpray drying the precursor raw material, and providing a simple and large-scale preparation method of spherical polyanionic anode material AVPO 4 F and A 3 V 2 (PO 4 ) 2 F 3 (wherein A is an alkali metal element: li, na, K). The preparation method is simple, the required compound raw materials and the additive auxiliary agent are subjected to spray granulation by a spray dryer, and then solid phase sintering is performed in one step.
The invention provides a preparation method of a fluorine-containing polyanion type anode material, wherein the chemical general formula of the fluorine polyanion type anode material is AVPO 4 F or A 3 V 2 (PO 4 ) 2 F 3 Wherein A is any one of alkali metal elements, particularly Li, na and K, and the preparation method comprises the following steps:
s1, preparing a precursor solution: dissolving organic acid in hot water at 80 ℃, adding a vanadium source, adding an alkali metal source and a phosphorus source in corresponding proportions after the solution is completely changed into blue to be dissolved, and uniformly mixing to obtain a solution A; adding a proper amount of template agent and additive into deionized water, and uniformly stirring to form a solution B;
wherein the ratio of the template agent to the alkali metal source is 10-30g/mol; the proportion of the additive and the alkali metal is 15-200g/mol;
s2, slowly dropping the uniformly dispersed solution B into the solution A to form a spraying mother solution;
s3, carrying out spray drying granulation on the spray mother liquor obtained in the S2 to obtain precursor powder;
and S4, calcining the precursor powder obtained in the step S3 at a high temperature of 600-900 ℃ for 2-10h under the inert atmosphere condition, collecting, sealing and storing.
Preferably, the organic acid comprises any one or more of oxalic acid dihydrate and citric acid.
Preferably, the vanadium source comprises any one or more of vanadium pentoxide, ammonium metavanadate, vanadyl sulfate, vanadyl oxalate, vanadium chloride, vanadyl acetylacetonate and vanadium acetylacetonate; more preferably, the source of vanadium is vanadium pentoxide.
Preferably, in step S1, the alkali metal source includes any one or more of lithium carbonate/sodium/potassium, lithium/sodium/potassium bicarbonate, lithium/sodium/potassium hydroxide, lithium/sodium/potassium citrate, lithium/sodium/potassium ethoxide, lithium/sodium/potassium sulfate, lithium/sodium/potassium fluoride, lithium/sodium/potassium nitrate, lithium/sodium/potassium acetate, lithium/sodium/potassium metavanadate, lithium/sodium/potassium fluorohydride, lithium/sodium/potassium pyrophosphate, and lithium/sodium/potassium hydrogen sulfate; more preferably, the alkali metal source is lithium/sodium/potassium fluoride.
Preferably, in step S1, the phosphorus source is any one or more of ammonium biphosphate, diammonium hydrogen phosphate, phosphoric acid, ammonium phosphate, and phosphorus pentoxide; more preferably, the source of phosphorus is diphosphonite.
Preferably, in step S1, the additive is a fluorine-containing compound slurry, the content of the fluorine-containing compound in the fluorine-containing compound slurry is 50wt%, and the fluorine-containing compound includes any one or two of Polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF).
Preferably, in step S1, the template agent is a high polymer, and includes one or two of polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA).
Preferably, in step S3, the spray drying conditions are: the inlet temperature is 200-250 ℃, the outlet temperature is 100-150 ℃, and the feeding speed is 6mL/min.
Preferably, in step S4, the temperature rise rate of the high-temperature calcination is 1-15 ℃/min.
The invention is characterized in that:
by adding different organic matters into a precursor solution and adopting an organic matter (oxalic acid dihydrate, polyvinylpyrrolidone and polyvinylidene fluoride) assisted spray drying method to successfully prepare high-performance AVPO 4 F and A 3 V 2 (PO 4 ) 2 F 3 (wherein A is an alkali metal element: li, na, K).
The addition of organic acid (such as oxalic acid dihydrate or citric acid) to the precursor solution mainly has the effect of reducing pentavalent vanadium in the vanadium source into trivalent vanadium, and the organic acid with reducing property can also be selected from citric acid and the like. According to the reduction degree, the content of the organic acid can be controlled, so that the reduction degree can be regulated and controlled.
The function of adding PTFE slurry into the precursor solution is mainly beneficial to providing a fluorine-rich and reducing environment for the material in the synthesis process, the PTFE slurry can be completely decomposed to generate a large amount of fluorine-containing gas in the high-temperature calcination process, the pure-phase synthesis of the material can be facilitated by controlling the adding amount of the PTFE slurry, and other fluorine-containing additives such as polyvinylidene fluoride (PVDF) can also be selected.
The template agent added into the precursor solution mainly plays a role of a template, and can effectively disperse the additive containing fluorine, and the AVPO can be successfully adjusted by controlling the addition amount of the additive 4 F and A 3 V 2 (PO 4 ) 2 F 3 (wherein A is alkali metal element: li, na, K) and can also be selected from other organic template agents, such as polyvinyl alcohol (PVA).
Spherical AVPO prepared by the method 4 F and A 3 V 2 (PO 4 ) 2 F 3 (wherein A is alkali metal element: li, na, K) has many advantages, such as high tap density, high phase purity, high specific surface area, etc.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 shows KVPO prepared by adding PTFE slurries in different ratios in examples 1 and 2 of the present invention and in comparative example 1 4 An X-ray diffraction (XRD) pattern of the polyanionic positive electrode material;
FIG. 2 shows KVPO prepared by adding different ratios of PVP templates in example 1 (a), example 3 (b), comparative example 2 (c) and comparative example 3 (d) of the present invention 4 Of F polyanionic positive electrode materialScanning Electron Microscope (SEM) images;
FIG. 3 is a graph of the electrochemical performance of a potassium ion half cell in example 1 of the present invention;
FIG. 4 shows LiVPO prepared by adding PTFE slurries of different ratios in example 4, example 5 and comparative example 4 of the present invention 4 XRD pattern (a) of F polyanionic positive electrode material and LiVPO prepared in example 4 4 SEM image (b) of F.
FIG. 5 shows LiVPO in example 4 of the present invention 4 F is an electrochemical performance graph of the lithium ion half cell;
FIG. 6 shows Na prepared by adding PTFE slurries in different ratios in example 6, example 7 and comparative example 5 of the present invention 3 V 2 (PO 4 ) 2 F 3 XRD pattern (a) of polyanionic cathode material and LiVPO prepared in example 6 4 SEM image of F (b);
FIG. 7 shows Na in example 6 of the present invention 3 V 2 (PO 4 ) 2 F 3 Electrochemical performance profile in sodium ion half cell.
Detailed Description
In order to facilitate understanding of the invention, the invention will be described more fully and in detail with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.
Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. The preferred embodiments and materials described herein are exemplary only, and modifications and variations may be made without departing from the principles of the embodiments of the invention, which are also to be considered within the scope of the invention.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
Example 1
Fluorine-containing polyanionSub-type positive electrode material KVPO 4 F, the preparation method specifically comprises the following steps:
(1) Dissolving 6.0g of oxalic acid dihydrate in hot water at the temperature of 80 ℃, sequentially adding the required vanadium pentoxide (0.01 mol), potassium fluoride (0.02 mol) and ammonium dihydrogen phosphate (0.02 mol) according to the stoichiometric ratio, and uniformly mixing to obtain a solution A; 0.3g PVP template, 2g PTFE slurry (PTFE: water =1, the same applies below) was added to deionized water and stirred well to form a B solution. And slowly dropping the uniformly dispersed solution B into the solution A to form a spraying mother solution.
(2) Spray drying: and (4) carrying out spray drying on the prepared spray mother liquor by using a spray dryer. The inlet temperature of the spray dryer was 200 ℃, the outlet temperature was 100 ℃, the feed rate was 6mL/min, and samples were collected after spraying was complete. The inlet temperature, feed rate, etc. can be adjusted accordingly depending on the production equipment.
(3) The precursor raw material is put into a high-temperature sintering furnace to be heated from room temperature to 750 ℃, the temperature is kept for 2 hours, the precursor raw material is cooled along with the furnace, the calcining atmosphere is argon, and the heating speed is 2 ℃ per minute. Taking out the powder, pulverizing, and grinding to obtain KVPO 4 And F, powder.
Example 2
Polyanionic type positive electrode material KVPO containing fluorine 4 F, the preparation method is the same as example 1 except that: in step (1), 4g of PTFE was added.
Comparative example 1
Polyanionic type positive electrode material KVPO containing fluorine 4 F, the preparation method is the same as example 1 except that: PTFE is not added in the step (1).
KVPO prepared in example 1, example 2 and comparative example 1 4 And F, carrying out XRD analysis. The XRD results are shown in FIG. 1. KVPO prepared without addition of PTFE additive in comparative example 1 4 F is less pure and contains more impurity phases because F volatilizes due to the temperature rise during spray drying, resulting in impure product. While the purity of the PTFE-added materials of example 1 and example 2 is higher, which shows that the PTFE provides an F source in the preparation process, the PTFE slurry is a fluorine-containing carbon source, and a reducing atmosphere is also provided in the material preparation process.
Example 3
Polyanionic type cathode material KVPO containing fluorine 4 F, a preparation method thereof, which is different from that: in step (1), 0.6g of PVP is added.
Comparative example 2
Polyanionic type cathode material KVPO containing fluorine 4 F, a preparation method thereof is different in that: in step (1), 0.9g of PVP is added.
Comparative example 3
Polyanionic type positive electrode material KVPO containing fluorine 4 F, a preparation method thereof is different in that: in the step (1), PVP is not added.
KVPO prepared in example 1, example 3 and comparative examples 2 to 3 4 And F, carrying out scanning electron microscope analysis, wherein the SEM appearance result is shown in figure 2. As shown in FIG. 2 (a), KVPO was prepared by spraying without PVP 4 F, the shape is irregular; from FIG. 2 (b, c) when a proper amount of PVP is added, KVPO 4 The shape of the F is regular sphere; as can be seen from FIG. 2 (d), excessive addition of PVP produced excessive gas during the calcination process, resulting in spherical breakage. The PVP template mainly plays a role in effectively dispersing PTFE slurry and is beneficial to carrying out spherical granulation in the spraying process.
KVPO prepared in example 1 4 F is used as a positive electrode material in a potassium ion half cell (wherein a potassium sheet is a counter electrode, KVPO 4 F is a positive electrode active material and the separator is a glass fiber) as shown in fig. 3. KVPO 4 F has higher charging and discharging capacity (0.2C has 85mAh g) -1 ) And better rate performance (25C still has 40mAh g -1 )。KVPO 4 After F is circulated for 100 circles under 5C high magnification, the capacity of the F still has 53mAh g -1 。
Example 4
Polyanion-type anode material LiVPO containing fluorine 4 F, the preparation method specifically comprises the following steps:
(1) Dissolving 3.8g of oxalic acid dihydrate in hot water at the temperature of 80 ℃, sequentially adding required vanadium pentoxide (0.01 mol), lithium fluoride (0.02 mol) and ammonium dihydrogen phosphate (0.02 mol) according to a stoichiometric ratio, and uniformly mixing to obtain a solution A; 0.3g of PVP template agent and 5g of PTFE slurry are added into deionized water and stirred uniformly to form a solution B. And slowly dropping the uniformly dispersed solution B into the solution A to form a spraying mother solution.
(2) Spray drying: and (4) carrying out spray drying on the prepared spray mother liquor by using a spray dryer. The inlet temperature of the spray dryer was 200 ℃, the outlet temperature was 100 ℃, the feed rate was 6mL/min, and samples were collected after spraying. The inlet temperature, feed rate, etc. can be adjusted accordingly depending on the production equipment.
(3) And (2) putting the precursor raw material into a high-temperature sintering furnace, heating the precursor raw material from room temperature to 750 ℃, preserving the heat for 2 hours, cooling the precursor raw material along with the furnace, wherein the calcining atmosphere is argon, and the heating speed is 2 ℃ per minute. Taking out the powder, crushing and grinding uniformly to obtain LiVPO 4 And F, powder.
Example 5
Polyanion-type anode material LiVPO containing fluorine 4 F, the preparation method is the same as example 4, except that: 2g of PTFE was added in step (1).
Comparative example 4
Polyanion-type anode material LiVPO containing fluorine 4 F, the preparation method is the same as example 4, except that: PTFE is not added in the step (1).
XRD phase purity analysis was performed on the materials prepared in example 4, example 5 and comparative example 4, and the results are shown in fig. 4. As can be seen from FIG. 4 (a), pure phase LiVPO was obtained 4 The key point of F is the addition amount of PTFE, and when PTFE is not added, li is contained in a large amount 3 V 2 (PO 4 ) 3 And (4) miscellaneous phase. Only when the amount of PTFE added reached 5g, high purity LiVPO could be obtained 4 F, pure phase.
FIG. 4 (b) shows pure phase LiVPO prepared in example 4 4 SEM image of F, spray-synthesized LiVPO 4 F is a regular sphere. FIG. 5 shows the results of the materials prepared in example 4, example 5 and comparative example 4 in a lithium ion half cell (in which the lithium plate is the counter electrode, liVPO) 4 F is a positive electrode active material), it can be seen that pure phase LiVPO prepared in example 4 4 F has a higher charge and discharge capacity (discharge capacity of 140.7mA at 0.1C current density) than the materials prepared in example 5 and comparative example 4h·g -1 ) And rate capability (discharge capacity still remains 100.5mAh g at 10C high current density) -1 )。
Example 6
Polyanionic anode material Na containing fluorine 3 V 2 (PO 4 ) 2 F 3 The preparation method comprises the following steps:
(1) Dissolving 3.8g of oxalic acid dihydrate in hot water at the temperature of 80 ℃, sequentially adding required vanadium pentoxide (0.01 mol), sodium fluoride (0.03 mol) and ammonium dihydrogen phosphate (0.02 mol) according to a stoichiometric ratio, and uniformly mixing to obtain a solution A; 0.6g of PVP template agent and 1g of PTFE slurry are added into deionized water and stirred uniformly to form a solution B. And slowly dropping the uniformly dispersed solution B into the solution A to form a spraying mother solution.
(2) Spray drying: and (4) carrying out spray drying on the prepared spray mother liquor by using a spray dryer. The inlet temperature of the spray dryer was 200 ℃, the outlet temperature was 100 ℃, the feed rate was 6mL/min, and samples were collected after spraying. The inlet temperature, feed rate, etc. can be adjusted accordingly depending on the production equipment.
(3) And (2) putting the precursor raw material into a high-temperature sintering furnace, heating the precursor raw material from room temperature to 750 ℃, preserving the heat for 2 hours, cooling the precursor raw material along with the furnace, wherein the calcining atmosphere is argon, and the heating speed is 2 ℃ per minute. Taking out the powder, pulverizing, and grinding to obtain Na 3 V 2 (PO 4 ) 2 F 3 And (3) powder.
Example 7
Polyanion-type positive electrode material Na containing fluorine 3 V 2 (PO 4 ) 2 F 3 The preparation method is the same as that of example 6, and is characterized in that: 0.5g of PTFE was added in step (1).
Comparative example 5
Polyanion-type anode material LiVPO containing fluorine 4 F, the preparation method is the same as example 6 except that: PTFE is not added in the step (1).
The XRD phase purity analysis was performed on the materials prepared in example 6, example 7 and comparative example 5, and the result is shown in fig. 6 (a). As is clear from the figure, when PTFE was not added, na was contained in a large amount 3 V 2 (PO 4 ) 3 And (4) miscellaneous phase. Only when the amount of PTFE added reached 1g, high-purity Na could be obtained 3 V 2 (PO 4 ) 2 F 3 Pure phase.
FIG. 6 (b) is pure phase Na prepared in example 6 3 V 2 (PO 4 ) 2 F 3 SEM picture of (1), spraying of synthesized Na 3 V 2 (PO 4 ) 2 F 3 Is in the shape of a regular sphere. FIG. 7 shows the results of the materials prepared in examples 6 and 7 and comparative example 5 in a sodium-ion half cell (where the sodium plate is the counter electrode, na) 3 V 2 (PO 4 ) 2 F 3 As a positive electrode active material, and a separator as glass fiber), it can be seen that pure-phase Na prepared in example 6 was present 3 V 2 (PO 4 ) 2 F 3 Compared with the materials prepared in the example 7 and the comparative example 5, the material has higher charge and discharge capacity and rate capability.
In summary, in the invention, organic matters (organic acid, template agent and additive) are added in the material synthesis process to assist spray drying for spherical granulation, wherein the additive (PTFE and PVDF) can be used as a reducing agent to provide a reducing atmosphere in the material calcination process to reduce a high-valence transition metal element into a low-valence transition metal element, and can also provide a fluorine-rich environment in the material synthesis process, thereby being beneficial to synthesizing a high-quality pure-phase fluorine-containing polyanion-type positive electrode material. The template agents (PVP and PVA) can effectively disperse the slurry of the additives (PTFE and PVDF) to play a role in adjusting and controlling the spherical shape of the template, and can also be carbonized into the material to carry out in-situ carbon coating in the process of calcining the material, so that the template agents and the material have a synergistic effect. The method is simple and easy to operate, has low cost and excellent repeatability, and can effectively prepare a series of fluorine-containing polyanion-type positive electrode materials (such as LiVPO) 4 F、NaVPO 4 F、KVPO 4 F、Li 3 V 2 (PO 4 ) 2 F 3 、Na 3 V 2 (PO 4 ) 2 F 3 、K 3 V 2 (PO 4 ) 2 F 3 Etc.) which can be easily and rapidly mass-produced.
The foregoing is illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the invention in any way. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.

Claims (5)

1. The preparation method of the fluorine-containing polyanionic cathode material is characterized in that the chemical general formula of the fluorine polyanionic cathode material is AVPO 4 F or A 3 V 2 (PO 4 ) 2 F 3 Wherein A is any one of alkali metal elements such as Li, na and K, and the preparation method comprises the following steps:
s1, preparing a precursor solution: dissolving organic acid in hot water at 80 ℃, adding a vanadium source according to the stoichiometric ratio in the chemical general formula of the synthesized material, adding an alkali metal source and a phosphorus source in corresponding stoichiometric ratios after the solution is completely changed into blue and dissolved, and uniformly mixing to obtain a solution A; adding a template agent and an additive into deionized water, and uniformly stirring to form a solution B;
wherein the ratio of the template agent to the alkali metal source is 10-30g/mol; the proportion of the additive and the alkali metal is 15-200g/mol; the organic acid comprises any one or more of oxalic acid dihydrate and citric acid; the additive is fluorine-containing compound slurry, and the fluorine-containing compound comprises any one or two of polytetrafluoroethylene and polyvinylidene fluoride; the template agent is a high polymer and comprises one or two of polyvinylpyrrolidone and polyvinyl alcohol;
s2, slowly dropping the uniformly dispersed solution B into the solution A to form a spraying mother solution;
s3, carrying out spray drying granulation on the spray mother liquor obtained in the S2 to obtain precursor powder;
and S4, calcining the precursor powder obtained in the step S3 at a high temperature of 600-900 ℃ for 2-10h under the inert atmosphere condition, collecting, sealing and storing.
2. The method according to claim 1, wherein in step S1, the vanadium source comprises any one or more of vanadium pentoxide, ammonium metavanadate, vanadyl sulfate, vanadyl oxalate, vanadium chloride, vanadyl acetylacetonate, and vanadium acetylacetonate; the alkali metal source comprises any one or more of lithium carbonate/sodium/potassium, lithium bicarbonate/sodium/potassium, lithium hydroxide/sodium/potassium, lithium citrate/sodium/potassium, lithium ethoxide/sodium/potassium, lithium sulfate/sodium/potassium, lithium fluoride/sodium/potassium, lithium nitrate/sodium/potassium, lithium acetate/sodium/potassium, lithium metavanadate/sodium/potassium, lithium fluorohydride/sodium/potassium, lithium pyrophosphate/sodium/potassium and lithium bisulfate/sodium/potassium; the phosphorus source is one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, phosphoric acid, ammonium phosphate and phosphorus pentoxide.
3. The method for producing a fluorine-containing polyanionic positive electrode material according to claim 1, wherein in step S1, the content of the fluorine-containing compound in the fluorine-containing compound slurry is 50wt% in step S1.
4. The method for producing a fluorine-containing polyanionic positive electrode material according to claim 1, wherein in step S3, the spray drying conditions are: the inlet temperature is 200-250 ℃, the outlet temperature is 100-150 ℃, and the feeding speed is 6mL/min.
5. The method for producing a fluorine-containing polyanionic positive electrode material according to claim 1, wherein in step S4, the temperature increase rate of the high-temperature calcination is 1 to 15 ℃/min.
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