Method for preparing sodium-ion battery polyanion positive electrode from waste lithium battery ternary material

Abstract

The application relates to a method for preparing a sodium-ion battery polyanion positive electrode from waste lithium battery ternary materials, and belongs to the lithium-ion battery recycling field.The method comprises the following steps: (1) tabletting, roasting, annealing and grinding a mixture of waste ternary positive electrode materials and a deconstruction agent to obtain roasted fine materials; (2) washing and filtering the roasted fine materials to obtain washed filter residues; (3) dissolving the washed filter residues in an acid solution, filtering and obtaining a transition metal ion salt A solution; (4) adding the solution A to solution B, adjusting the pH, heating to form a gel, drying, grinding and calcining to obtain Na 2+2x M 2‑x [(XO m ) n ‑ ] z materials; the solution A comprises a sodium salt, an anion salt and a transition metal ion salt A solution; and the solution B comprises a chelating agent and a reducing agent.The method is simple in process and simple in flow, and through a new recycling idea, the purpose of resource recycling is achieved.

Description

TECHNICAL FIELD

[0001] The application relates to a method for preparing a polyanion positive electrode of a sodium ion battery from waste lithium battery ternary material, and belongs to the field of lithium ion battery recycling. BACKGROUND

[0002] With the coming of the scrapping period of new energy vehicles, the recycling problem needs to be solved to achieve the sustainable development of the lithium ion battery industry. Among the key components of the lithium ion battery, the recycling value of the positive electrode material is the highest, especially the ternary positive electrode material containing Li, Ni, Co and Mn elements.

[0003] The polyanion type sodium battery positive electrode material is the most studied positive electrode material due to its simple synthesis method, good comprehensive performance and large application potential, and includes phosphate, pyrophosphate, fluorophosphate, sodium ion conductor, sulfate, borate and molybdate, and its chemical general formula is Na 2+2x M 2-x [(XO m ) n - ] z , wherein M is generally a transition metal element (including Ni, Co and Mn), and X is a non-metal element such as P, S, B, Si and Mo.

[0004] However, the current recycling work is mostly focused on the separation and purification of single elements, recycling into corresponding raw materials or repairing and regenerating into the same ternary positive electrode material, the process is relatively complicated, the input cost is large, and the purity of the recycled raw material is limited, and the cost performance is low. Therefore, recycling and regenerating other energy storage materials through a relatively simple process is another better recycling and utilization form. SUMMARY

[0005] According to one aspect of the application, a method for preparing a polyanion positive electrode of a sodium ion battery from waste lithium battery ternary material is provided, the method recycles transition metal ion salt from waste lithium battery ternary positive electrode material to regenerate a sodium ion battery positive electrode material, the method is simple in process and simple in process, and different types of polyanion positive electrode materials can be prepared by adjusting the type and content of the metal ion source. The application provides a new idea of recycling and regeneration to achieve the purpose of resource recycling and utilization.

[0006] The method for preparing a polyanion positive electrode of a sodium ion battery from waste lithium battery ternary material provided in the application comprises the following steps:

[0007] (1) tabletting the mixture of waste ternary positive electrode material and deconstruction agent, calcining, annealing, grinding, to obtain calcined fine material;

[0008] (2) washing the calcined fine material with water, filtering, to obtain water washing residue;

[0009] (3) dissolving the water-washing filter residue with an acid solution, filtering, and obtaining a transition metal ion salt A solution;

[0010] (4) adding the solution A to the solution B, adjusting pH, heating to form a gel, drying, grinding, and calcining to obtain Na 2+ 2x M 2-x [(XO m ) n - ] z material;

[0011] The solution A comprises a sodium salt, an anion salt, and a transition metal ion salt A solution;

[0012] The solution B comprises a chelating agent and a reducing agent;

[0013] The M comprises Ni, Co, and Mn elements;

[0014] [(XO m ) n - ] z corresponding to the acid radical in the anion salt;

[0015] 0 < x < 1.

[0016] Optionally, the waste and old ternary positive electrode material is LiNi x Co y Mn 1-x-y O2 material, wherein 0 < x < 1, 0 < y < 1, and x + y < 1.

[0017] Optionally, the waste and old ternary positive electrode material is LiNi 0.33 Co 0.33 Mn 0.33 O2.

[0018] Optionally, the deconstruction agent is sodium hydroxide.

[0019] Optionally, the mass ratio of the waste and old ternary positive electrode material to the deconstruction agent is (1-5):1, preferably, the mass ratio of the waste and old ternary positive electrode material to the deconstruction agent is (2-4):1.

[0020] Optionally, the mass ratio of the waste and old ternary positive electrode material to the deconstruction agent is independently any one of 1:1, 2:1, 3:1, 4:1, 5:1 or a range value between any two of the above.

[0021] Optionally, the temperature of the calcination is 700-900℃; preferably, the temperature of the calcination is 800℃.

[0022] Optionally, the time for the calcination is 1-5h; preferably, the time for the calcination is 2h.

[0023] Optionally, the atmosphere for the calcination is an air atmosphere.

[0024] Optionally, the mixing manner of the waste and old ternary positive electrode material and the deconstruction agent is a ball milling manner.

[0025] Optionally, in step (2), the temperature for the water washing is 70-90℃; preferably, the temperature for the water washing is 80℃.

[0026] Optionally, in step (2), the time for the water washing is 1-5h; preferably, the time for the water washing is 2h.

[0027] Optionally, in step (2), the mass ratio of the calcined fine powder and water during the water washing is 1:(10-20); preferably, in step (2), the mass ratio of the calcined fine powder and water during the water washing is 1:(13-17); more preferably, in step (2), the mass ratio of the calcined fine powder and water during the water washing is 1:15.

[0028] After the water washing in step (2), a water washing residue rich in nickel, cobalt, manganese and sodium elements is obtained.

[0029] After the water washing in step (2), a water washing liquid, i.e. a lithium leaching liquid, is obtained, which can be purified or subjected to other reactions, which are not limited by the present application, but are not described in detail.

[0030] Optionally, in step (3), the acid solution is a sulfuric acid solution.

[0031] Optionally, the concentration of the sulfuric acid solution is 1-5wt%; preferably, the concentration of the sulfuric acid solution is 2-3.5wt%.

[0032] Optionally, the sulfuric acid solution is obtained by diluting concentrated sulfuric acid, and the concentrated sulfuric acid:water washing residue = 0.6mL:(0.5-1.5)g; preferably, the concentrated sulfuric acid:water washing residue = 0.6mL:(0.8-1.2)g.

[0033] Optionally, the anion salt is selected from any one or more of a phosphate, a pyrophosphate, a fluorophosphate, a sulfate, a borate and a molybdate; preferably, the anion salt is a molybdate; more preferably, the anion salt is ammonium molybdate tetrahydrate.

[0034] Optionally, Na 2+2x M 2-x [(XO m ) n - ] z , 0

[0035] Optionally, the sodium salt is selected from any one or more of sodium citrate, sodium acetate, sodium sulfate, sodium carbonate, preferably sodium citrate.

[0036] Optionally, the solution A further comprises a transition metal ion salt B to synthesize a corresponding target Na 2+2x M 2-x [(XO m ) n - ] z material.

[0037] Optionally, the transition metal ion salt B is a water-soluble transition metal ion salt;

[0038] The water-soluble transition metal ion salt is selected from one or more of a water-soluble Ni salt, a water-soluble Co salt, a water-soluble Mn salt, a water-soluble Fe salt, a water-soluble V salt.

[0039] Optionally, the reducing agent is selected from any one or more of ascorbic acid, formic acid, oxalic acid, oxalic acid, citric acid, sulfurous acid, phosphoric acid.

[0040] Optionally, the chelating agent is selected from any one or more of citric acid, sodium citrate, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, tripolyphosphoric acid, sodium tripolyphosphate, nitrilotriacetic acid, sodium nitrilotriacetate.

[0041] Optionally, the M further comprises Fe, V.

[0042] Optionally, the molar ratio of the chelating agent to the transition metal ions is 1:(0.1-2); the transition metal ions include transition metal ions in the transition metal ion salt A and the transition metal ion salt B; preferably, the molar ratio of the chelating agent to the transition metal ions is 1:(0.5-1.5); the transition metal ions include transition metal ions in the transition metal ion salt A and the transition metal ion salt B; more preferably, the molar ratio of the chelating agent to the transition metal ions is 1:1; the transition metal ions include transition metal ions in the transition metal ion salt A and the transition metal ion salt B.

[0043] Optionally, the mass ratio of the reducing agent to the chelating agent is 1:(1-4); preferably, the mass ratio of the reducing agent to the chelating agent is 1:(1.5-2.5).

[0044] Optionally, the Na 2+2x M 2-x [(XO m ) n - ] z is Na 2.8 Ni 0.53 Co 0.53 Mn 0.53 (MoO4)3or Na2.8 Ni 0.4 Co 0.4 Mn 0.8 (MoO4)3.

[0045] Optionally, adjust the pH to 5-6.

[0046] Optionally, an alkaline solution is used to adjust the pH; preferably, the alkaline solution is ammonia.

[0047] Optionally, the heating temperature is 60-100℃; preferably, the heating temperature is 80-90℃.

[0048] Optionally, the heating time is 3-8 hours; preferably, the heating time is 5-6 hours.

[0049] Optionally, in step (4), the drying is vacuum drying.

[0050] Optionally, in step (4), the drying temperature is 100℃-150℃; preferably, in step (4), the drying temperature is 110℃-130℃; more preferably, in step (4), the drying temperature is 120℃.

[0051] Optionally, the atmosphere during calcination is air or oxygen.

[0052] Optionally, calcination includes a pre-sintering stage and a sintering stage;

[0053] During the pre-sintering stage, the pre-sintering temperature is 100-400℃, the pre-sintering time is 4-8h, and the heating rate is 1-10℃ / min.

[0054] During the sintering stage, the sintering temperature is 500-800℃, the sintering time is 5-15h, and the heating rate is 5-15℃ / min.

[0055] Preferably, in the pre-sintering stage, the pre-sintering temperature is 250-350℃, the pre-sintering time is 5-7h, and the heating rate is 3-7℃ / min.

[0056] Preferably, during the sintering stage, the sintering temperature is 600-700℃, the sintering time is 6-10h, and the heating rate is 8-12℃ / min.

[0057] Optionally, tablets are pressed after the pre-sintering stage, followed by the sintering stage.

[0058] In one embodiment, a method for preparing a sodium-ion battery polyanion cathode from waste lithium-ion battery ternary materials includes the following steps: (1) mixing the waste ternary cathode material with a destructive agent powder using a ball mill. The mixed powder is then pressed into sheets, calcined, and the annealed lumps are ground to obtain calcined fines.

[0059] (2) Water washing and filtering to obtain water washing filter residue rich in Ni, Co, Mn, and Na elements, and the lithium leaching solution obtained after water washing can be purified or subjected to other reactions.

[0060] (3) Dissolving the water washing filter residue with sulfuric acid and filtering to obtain an leaching solution rich in nickel, cobalt, manganese, and sodium ions. The concentrations of the ions in the leaching solution are measured by ICP-OES (inductively coupled plasma atomic emission spectrometer).

[0061] (4) Preparing a sodium ion positive electrode material by a sol-gel method:

[0062] According to the element composition ratio of the target polyanion positive electrode material, a corresponding amount of sodium salt, anion salt, and additional transition metal ion salt is added to the above leaching solution, denoted as solution A.

[0063] A corresponding chelating agent is weighed and a small amount of reducing agent is added to configure a solution with a certain concentration, denoted as solution B.

[0064] Solution A is added dropwise to solution B, and the pH is adjusted to 5-6 with dilute ammonia water. The solvent is evaporated by heating to form a gel. The gel is vacuum dried and ground into a powder, and after pre-sintering and further calcination, the target Na 2+2x M 2-x [(XO m ) n - ] z material, wherein M contains Ni, Co, and Mn elements.

[0065] The beneficial effects that can be produced by the present application include:

[0066] 1) The method for preparing a sodium ion battery polyanion positive electrode provided by the present application recovers waste lithium battery ternary positive electrode material to obtain a solution rich in Ni, Co, Mn, and Na ions, and further generates a sodium ion battery polyanion positive electrode material through a simple reaction. The method is simple in process and simple in flow, and different types of polyanion positive electrode materials can be prepared by adjusting the types and contents of metal ion sources.

[0067] 2) The method for preparing a sodium ion battery polyanion positive electrode provided by the present application, in the recovery process, the valuable Ni, Co, and Mn ions recovered are active metals of the polyanion positive electrode material, which can effectively provide capacity. And by additionally adding other transition metal ions, the ratio between the transition metal ions can be adjusted to control the charge and discharge potential and optimize the electrochemical performance.

[0068] 3) The method for preparing a polyanion positive electrode of a sodium ion battery from waste lithium battery ternary material provided in the application, a small amount of Li ions contained in the leaching solution will be embedded in the crystal lattice even when the polyanion positive electrode material is synthesized, and will be removed in the subsequent battery charging process, which will not affect the performance of the battery.

[0069] 4) The method for preparing a polyanion positive electrode of a sodium ion battery from waste lithium battery ternary material provided in the application, NaOH is selected as the deconstruction agent, and the introduced Na ions can be used as the sodium source of the positive electrode material, that is, the Li ions can be effectively leached out without introducing impurities.

[0070] 5) The method for preparing a polyanion positive electrode of a sodium ion battery from waste lithium battery ternary material provided in the application, when the sodium ion battery positive electrode material is synthesized, the sol-gel method is selected, which has mature process and simple flow, and can effectively recycle and regenerate the sodium ion battery polyanion material, thereby realizing the recycling of resources to a certain extent. BRIEF DESCRIPTION OF DRAWINGS

[0071] Figure 1 Figure is a SEM image of the precursor powder obtained in Example 1 of the application;

[0072] Figure 2 Figure is a SEM image of the polyanion positive electrode material of the sodium ion battery of Example 1 of the application, with a size of 30 μm;

[0073] Figure 3 Figure is an X-ray diffraction pattern of the polyanion positive electrode material of the sodium ion battery of Example 1 of the application;

[0074] Figure 4 Figure is the charge-discharge curve of the battery obtained in Example 1;

[0075] Figure 5 Figure is the charge-discharge curve of the battery obtained in Example 2;

[0076] Figure 6 Figure is a flow chart of the method for preparing a polyanion positive electrode of a sodium ion battery from waste lithium battery ternary material provided in the application. DETAILED DESCRIPTION

[0077] The application will be described in detail below in conjunction with examples, but the application is not limited to these examples.

[0078] Unless otherwise specified, the raw materials in the examples of the application are purchased through commercial channels.

[0079] The instrument for SEM testing is a Thermo Fisher Apreo S LoVac microscope, and the test conditions are a voltage of 30.00 KV.

[0080] The instrument for X-ray diffraction is a Miniflex 600 powder diffractometer of Rigaku Corporation of Japan, and Cu Kα is used as the excitation light source.

[0081] The instrument for testing the charge-discharge performance of the battery is a CT2001A battery test system of Blue Electronic, and the test range of voltage and current is 5V and 5mA.

[0082] As Figure 6 , the flow chart of the method for preparing a sodium ion battery polyanion positive electrode from waste lithium battery ternary material, comprising the following steps:

[0083] (1) Mix the waste ternary positive electrode material with sodium hydroxide powder as a deconstruction agent uniformly. After mixing, the powder is tabletized, calcined, and the block-shaped material after annealing is ground to obtain calcined fine material.

[0084] (2) Wash with deionized water and filter to obtain a water-washed filter residue rich in Ni, Co, Mn, and Na elements. The lithium leaching solution obtained after the water washing liquid can be purified or subjected to other reactions.

[0085] (3) Dissolve the water-washed filter residue with sulfuric acid and filter to obtain a leaching solution rich in nickel, cobalt, manganese, and sodium ions. The concentrations of the ions in the leaching solution are measured by ICP-OES (inductively coupled plasma atomic emission spectrometer).

[0086] (4) Prepare a sodium ion positive electrode material by a sol-gel method:

[0087] According to the element composition ratio of the target polyanion positive electrode material, a corresponding amount of sodium salt, anion salt, and additional transition metal ion salt is added to the above leaching solution, denoted as solution A.

[0088] A corresponding chelating agent is weighed and a small amount of reducing agent is added to configure a solution with a certain concentration, denoted as solution B.

[0089] Solution A is added dropwise to solution B, and the pH is adjusted to 5-6 with dilute ammonia water. The solvent is evaporated by heating to form a gel. The gel is dried in vacuum and ground into powder, and after pre-sintering and further calcination, the target Na 2+2x M 2-x [(XO m ) n - ] z material, wherein M contains Ni, Co, and Mn elements.

[0090] Example 1

[0091] (1) Weigh 1g of waste lithium nickel cobalt manganese oxide powder (containing LiNi 0.33 Co 0.33 Mn 0.33O2) and 0.33 g of sodium hydroxide solid, grind and mix uniformly with a mortar. The mixed powder is pressed into small round tablets with a mold and then fired at 800°C for 2 h in air atmosphere. After annealing to room temperature, the block is ball-milled into fine powder.

[0092] (2) Pour the above powder into 15 mL of deionized water and stir at 80°C for 2 h. After water washing, suction filtration is performed to obtain a water-washed residue rich in nickel, cobalt, manganese and sodium elements.

[0093] (3) Measure 0.6 mL of concentrated sulfuric acid and add dropwise to 20 mL of deionized water for dilution. After dilution, add the above water-washed residue, stir for 12 h and then suction filter to obtain a nickel, cobalt, manganese and sodium leaching solution. The concentrations of nickel, cobalt, manganese and sodium ions are measured by ICP-OES technology to be 5.28 g / L, 5.25 g / L, 4.86 g / L and 3.9 g / L, respectively.

[0094] (4) According to the stoichiometric ratio of Na 2.8 M 1.6 (MoO4)3 chemical formula of each metal ion (M is provided by Ni, Co, Mn ions in the leaching solution), and deduct the original sodium ion content in the above leaching solution, weigh 1.2 g of sodium citrate dihydrate and 5.3 g of ammonium molybdate tetrahydrate, and dissolve in the leaching solution in (3) above.

[0095] (5) According to the molar ratio of citric acid to transition metal ions = 1:1, weigh 3.5 g of citric acid monohydrate, dissolve in 20 mL of deionized water, and add 2 g of ascorbic acid, stir until transparent.

[0096] (6) Add the solution in (4) dropwise to (5), stir for 10 min. Adjust the pH to 5-6 with ammonia water, and heat and stir at 80°C for 5-6 h to form a gel. After drying the gel in a vacuum at 120°C, grind into a precursor powder, then heat to 300°C at a heating rate of 5°C / min in a muffle furnace, and pre-sinter for 6 h. The sintered powder is pressed into a tablet, then heated to 650°C at a heating rate of 10°C / min, and calcined for 8 h to obtain a sodium positive electrode material, denoted as R-Na 2.8 Ni 0.53 Co 0.53 Mn 0.53 (MoO4)3.

[0097] Example 2

[0098] (1) Weigh 1 g of waste lithium nickel cobalt manganese oxide powder (containing LiNi 0.33 Co 0.33 Mn 0.33O2) and 0.33 g of sodium hydroxide solid, grind and mix uniformly with a mortar. The mixed powder is pressed into small round tablets with a mold, and then fired at 800°C for 2 h in air atmosphere. After annealing to room temperature, the block is ball-milled into fine powder.

[0099] (2) Pour the above powder into 15 mL of deionized water, and stir at 80°C for 2 h. After water washing, suction filtration is performed to obtain a water-washed residue rich in nickel, cobalt, manganese, and sodium elements.

[0100] (3) Measure 0.6 mL of concentrated sulfuric acid, and add dropwise to 20 mL of deionized water for dilution. After dilution, add the above water-washed residue, stir for 12 h, and then perform suction filtration to obtain a nickel, cobalt, manganese, and sodium leaching solution. The concentrations of nickel, cobalt, manganese, and sodium ions are measured by ICP-OES technology to be 5.28 g / L, 5.25 g / L, 4.86 g / L, and 3.9 g / L, respectively.

[0101] (4) According to the stoichiometric ratio of each metal ion in the chemical formula Na 2.8 Ni 0.4 Co 0.4 Mn 0.8 (MoO4)3, that is, the nickel, cobalt, and manganese ions are provided by the leaching solution + part of manganese acetate tetrahydrate, and deducting the original sodium ion content in the above leaching solution, weigh 1.64 g of manganese acetate tetrahydrate, 2.25 g of sodium citrate dihydrate, and 7.4 g of molybdate tetrahydrate, and dissolve in the leaching solution in (3) above.

[0102] (5) According to the molar ratio of citric acid to transition metal ions = 1:1, weigh 4.9 g of citric acid monohydrate, dissolve in 30 mL of deionized water, and add 2 g of ascorbic acid, and stir until transparent.

[0103] (6) Add the solution in (4) dropwise to (5), and stir for 10 min. Adjust the pH to 5-6 with ammonia water, and heat and stir in a water bath at 80°C for 5-6 h to form a gel. After vacuum drying of the gel at 120°C, grind the precursor powder into a powder, and heat to 300°C at a heating rate of 5°C / min in a muffle furnace, and pre-sinter for 6 h. After sintering, the powder is pressed into a tablet, and then heated to 650°C at a heating rate of 10°C / min, and calcined for 8 h to obtain a sodium electric positive electrode material, denoted as R-Na 2.8 Ni 0.4 Co 0.4 Mn 0.8 (MoO4)3.

[0104] The powders obtained in Example 1 and Example 2 above were mixed with super P conductive agent and PVDF binder in a mass ratio of 7:2:1 to prepare a slurry, which was coated on an aluminum foil to prepare an electrode sheet with a diameter of 14 mm. A half-cell was assembled with sodium metal as the negative electrode, an EC:DEC = 1:1 v / v solution containing 1M NaClO4 as the electrolyte, and Whatman glass fiber as the separator, and electrochemical tests were performed. The voltage test range was 1.5V-4.4V.

[0105] Figure 1 The microstructure of the sodium-ion battery polyanion positive electrode material after further calcination of the precursor powder obtained in step (6) of Example 1 is shown in Figure 2 , with a size of 30μm and a particle size of about 5μm-30μm.

[0106] Figure 3 The X-ray diffraction pattern of the sodium-ion battery polyanion positive electrode material of Example 1 is shown in , with a main peak at (003) and a diffraction angle position of 30.76°, which is consistent with the CCDC No. 1522247 data of the standard sample, indicating that the target polyanion material was successfully synthesized.

[0107] Figure 4 and Figure 5 are the charge-discharge curves of the batteries obtained in Example 1 and Example 2, respectively, with a discharge capacity of 81.3mAh / g and 85mAh / g at a current density of 0.1C, respectively. This application successfully recovers valuable metals from waste lithium battery ternary materials and prepares a sodium-ion battery polyanion positive electrode material.

[0108] The above is only a few embodiments of the present application, and does not limit the present application in any form. Although the preferred embodiments of the present application are disclosed as above, they are not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, which are equivalent to equivalent embodiments and belong to the scope of the technical solution.

Claims

1. A method for preparing a polyanion cathode for a sodium-ion battery from waste lithium battery ternary material, characterized in that, It comprises the following steps: (1) tabletting, roasting, annealing, grinding the mixture of waste ternary positive electrode material and deconstruction agent to obtain roasted fine material; (2) washing, filtering the roasted fine material to obtain washed filter residue; (3) dissolving the washed filter residue with acid solution, filtering to obtain transition metal ion salt A solution; (4) Add solution A to solution B, adjust pH, heat to form gel, dry, grind, calcine to obtain Na 2+2x M 2-x [(XO m ) n - ] z material; The solution A comprises sodium salt, anion salt, transition metal ion salt A solution; The solution B comprises chelating agent and reducing agent; M comprises Ni, Co, Mn elements; [(XO m ) n - ] z corresponding anion in the salt; wherein the acid radical is a molybdate radical; 0＜x＜1。 2. The method for preparing sodium-ion battery polyanion cathodes from waste lithium-ion battery ternary materials according to claim 1, characterized in that, The waste ternary positive electrode material is LiNi x Co y Mn 1-x-y O2 material, wherein 0 < x < 1, 0 < y < 1, and x + y < 1.

3. The method for preparing sodium-ion battery polyanion cathodes from waste lithium-ion battery ternary materials according to claim 2, characterized in that, The waste ternary positive electrode material is LiNi 0.33 Co 0.33 Mn 0.33 O2.

4. The method for preparing sodium-ion battery polyanion cathodes from waste lithium-ion battery ternary materials according to claim 1, characterized in that, The deconstruction agent is sodium hydroxide.

5. The method for preparing sodium-ion battery polyanion cathode from waste lithium battery ternary material according to claim 4, characterized in that, The mass ratio of waste ternary positive electrode material to deconstruction agent is (1-5):

1.

6. The method for preparing sodium-ion battery polyanion cathode from waste lithium battery ternary material according to claim 4, characterized in that, The mass ratio of waste ternary positive electrode material to deconstruction agent is (2-4):

1.

7. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The roasting temperature is 700-900℃.

8. The method for preparing sodium-ion battery polyanion cathodes from waste lithium-ion battery ternary materials according to claim 1, characterized in that, The roasting time is 1-5h.

9. The method for preparing sodium-ion battery polyanion cathodes from waste lithium-ion battery ternary materials according to claim 1, characterized in that, The washing temperature is 70-90℃.

10. The method for preparing sodium-ion battery polyanion cathode from waste lithium battery ternary material according to claim 1, characterized in that, The washing time is 1-5h.

11. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The mass ratio of roasted fine material to water during washing is 1:(10-20).

12. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The sodium salt is selected from any one or more of sodium citrate, sodium acetate, sodium sulfate, sodium carbonate.

13. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The reducing agent is selected from any one or more of ascorbic acid, formic acid, oxalic acid, ethanedioic acid, citric acid, sulfurous acid, phosphoric acid.

14. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The chelating agent is selected from any one or more of citric acid, sodium citrate, ethanedioic acid tetraacetic acid, ethanedioic acid tetraacetic acid disodium, tripolyphosphoric acid, sodium tripolyphosphate, amino triacetate, sodium amino triacetate.

15. The method for preparing sodium-ion battery polyanion cathodes from waste lithium-ion battery ternary materials according to claim 1, characterized in that, M also comprises Fe and / or V elements.

16. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The solution A further comprises transition metal ion salt B; The transition metal ion salt B is water-soluble transition metal ion salt; The water-soluble transition metal ion salt is selected from one or more of water-soluble Ni salt, water-soluble Co salt, water-soluble Mn salt, water-soluble Fe salt, water-soluble V salt.

17. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The molar ratio of chelating agent to transition metal ion is 1:(0.1-2); the transition metal ion comprises transition metal ions in transition metal ion salt A and transition metal ion salt B.

18. The method for preparing sodium-ion battery polyanion cathodes from waste lithium-ion battery ternary materials according to claim 17, characterized in that, The mass ratio of reducing agent to chelating agent is 1:(1-4).

19. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The drying temperature is 100℃-150℃.

20. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. The calcination comprises a pre-sintering stage and a sintering stage; In the pre-sintering stage, the pre-sintering temperature is 100-400℃, the pre-sintering time is 4-8h, and the heating rate is 1-10℃ / min; In the sintering stage, the sintering temperature is 500-800℃, the sintering time is 5-15h, and the heating rate is 5-15℃ / min.

21. The method of claim 1, wherein the sodium-ion battery polyanion cathode is prepared from the waste lithium battery ternary material. Na 2+2x M 2-x [(XO m ) n - ] z for Na 2.8 Ni 0.53 Co 0.53 Mn 0.53 (MoO4)3or Na 2.8 Ni 0.4 Co 0.4 Mn 0.8 (MoO4)3.

Images