Electrode material and electrolyte for fuel cell and preparation method of electrode material and electrolyte

Abstract

The invention provides an electrode material and an electrolyte for a fuel cell and a preparation method of the electrode material and the electrolyte, and belongs to the technical field of fuel cells. Metal ions (at least one of lithium ions, sodium ions, potassium ions, nickel ions, cobalt ions and manganese ions) are adopted to supplement the electrode material, loss of the metal ions in the electrode material can be made up, then sintering or hydrothermal reaction is adopted, the structure of the electrode material can be recovered, and the performance of the electrode material is improved. Therefore, the structural stability and the conductivity of the electrode material are improved; metal ions (at least one of lithium ions, sodium ions, potassium ions, nickel ions, cobalt ions and manganese ions) are adopted to supplement the solid electrolyte, loss of the metal ions in the solid electrolyte can be made up, then sintering or hydrothermal reaction is adopted, the structure of the electrode material can be recovered, and the performance of the electrode material is improved. Therefore, the ionic conductivity and the interfacial compatibility of the solid electrolyte are optimized, the performance of the electrode material and the electrolyte is remarkably improved, and the performance of the fuel cell is further ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and particularly relates to an electrode material and an electrolyte for a fuel cell and a preparation method thereof. Background Art

[0002] With the wide application of renewable energy storage and portable electronic devices, the production and use of lithium-ion batteries have increased sharply, resulting in a large number of waste batteries. The electrode materials and electrolyte materials in the batteries often only have a certain degree of performance degradation. If directly discarded, on the one hand, it will cause environmental pollution, and on the other hand, it will cause waste of resources. At present, there are many methods for recycling waste lithium batteries, including hydrometallurgy, pyrometallurgy, and heat treatment, etc. However, the performance of the electrode materials and electrolytes prepared by these methods is poor, affecting the use of the batteries. Therefore, how to improve the recycling method to improve the performance of the electrode materials and electrolytes, so as to ensure the performance of the batteries has become a technical problem to be solved urgently in this field. Summary of the Invention

[0003] The purpose of the present invention is to provide an electrode material and an electrolyte for a fuel cell and a preparation method thereof. The preparation method provided by the present invention can improve the performance of the electrode material and the electrolyte for a fuel cell, thereby ensuring the performance of the battery.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides a preparation method for an electrode material and an electrolyte for a fuel cell, comprising the following steps:

[0006] (1) Mix the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery with a metal salt and / or an alkaline substance to obtain a first mixture;

[0007] (2) Perform a first sintering on the first mixture obtained in the step (1) to obtain an electrode material / electrolyte for a fuel cell;

[0008] Or,

[0009] 1) Mix the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery with an aqueous solution of a metal salt and / or an alkaline substance to obtain a second mixture;

[0010] 2) Perform a hydrothermal reaction on the second mixture obtained in the step 1) to obtain an electrode material / electrolyte for a fuel cell;

[0011] Or,

[0012] I. Mix the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery with a leaching agent for leaching to obtain a leachate;

[0013] II. Mix the leachate obtained in the step I with a metal salt and / or an alkaline substance to obtain a third mixture;

[0014] III. Subject the third mixture obtained in the step II to gelation and second sintering in sequence to obtain an electrode material / electrolyte for a fuel cell;

[0015] The metal salt is at least one of lithium salts, sodium salts, potassium salts, nickel salts, cobalt salts and manganese salts; the alkaline substance is at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, nickel hydroxide, cobalt hydroxide and manganese hydroxide.

[0016] Preferably, the electrode material of the waste lithium-ion battery in the step (1), the electrode material of the waste lithium-ion battery in the step 1), and the electrode material of the waste lithium-ion battery in the step I independently include at least one of lithium cobaltate, lithium nickelate, lithium manganate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, lithium ferrite, lithium titanate, lithium cobalt aluminate, lithium vanadate, doped lithium cobaltate, doped lithium nickelate, doped lithium manganate, doped lithium nickel cobalt manganate, doped lithium nickel cobalt aluminate, doped lithium iron phosphate, doped lithium ferrite, doped lithium titanate, doped lithium cobalt aluminate and doped lithium vanadate.

[0017] Preferably, the solid electrolyte of the waste lithium-ion battery in the step (1), the solid electrolyte of the waste lithium-ion battery in the step 1), and the solid electrolyte of the waste lithium-ion battery in the step I independently include one of oxide solid electrolytes, sulfide solid electrolytes, polymer solid electrolytes and composite solid electrolytes.

[0018] Preferably, the mass content of the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery in the first mixture in the step (1) is 20-99%.

[0019] Preferably, the temperature of the first sintering in the step (2) is 100-1500 °C, and the time of the first sintering is 1-20 h.

[0020] Preferably, the molar ratio of the metal ions in the metal salt to the transition metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery in the step 1) is (0.1-1):1; the molar ratio of the alkali metal ions in the alkaline substance to the transition metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery is (0.1-1):1.

[0021] Preferably, in the step 2), the temperature of the hydrothermal reaction is 80 - 240 °C, and the time of the hydrothermal reaction is 1 - 20 h.

[0022] Preferably, the leaching agent in the step I includes one of citric acid, lactic acid, malic acid, hydrochloric acid, and nitric acid.

[0023] Preferably, in the step III, the temperature of the second sintering is 200 - 1500 °C, and the time of the second sintering is 2 - 20 h.

[0024] The present invention also provides an electrode material and an electrolyte for a fuel cell prepared by the preparation method described in the above technical solution.

[0025] The present invention uses metal ions (at least one of lithium ions, sodium ions, potassium ions, nickel ions, cobalt ions, and manganese ions) to supplement the electrode material of the waste lithium-ion battery, which can make up for the loss of metal ions in the electrode material. Then, by using sintering or hydrothermal reaction, the structure of the electrode material can be restored, thereby improving the structural stability and conductivity of the electrode material; using metal ions (at least one of lithium ions, sodium ions, potassium ions, nickel ions, cobalt ions, and manganese ions) to supplement the solid electrolyte of the waste lithium-ion battery can make up for the loss of metal ions in the solid electrolyte. Then, by using sintering or hydrothermal reaction, the structure of the electrode material can be restored, thereby optimizing the ionic conductivity and interfacial compatibility of the solid electrolyte, significantly improving the performance of the electrode material and the electrolyte, and further ensuring the performance of the fuel cell. The experimental results show that the IVP performance of the electrode material for a fuel cell prepared by the preparation method provided by the present invention has been significantly improved. Description of the Drawings

[0026] Figure 1 It is the refined X-ray diffraction pattern of the NCML powder obtained in steps (1) of Examples 1 - 2;

[0027] Figure 2 It is the refined X-ray diffraction pattern of the electrode material for a fuel cell prepared in Example 2;

[0028] Figure 3 It is the IVP test chart of the fuel cell prepared by using the NCML powder in Example 1 and the electrode material in Example 1;

[0029] Figure 4 It is the IVP test chart of the fuel cell prepared by using the NCML powder in Example 2 and the electrode material in Example 2;

[0030] Figure 5 It is the IVP test chart of the fuel cell prepared by using the LiCoO 2 powder in Example 3 and the electrode material in Example 3;

[0031] Figure 6 Scanning electron microscope image of the electrode material for fuel cells prepared in Example 3;

[0032] Figure 7 IVP test chart of the fuel cell prepared using the NCML powder in Example 4 and the electrode material in Example 4;

[0033] Figure 8 IVP test chart of the fuel cell prepared using the NCML powder in Example 6 and the electrode material in Example 6. Detailed implementation manners

[0034] The present invention provides a preparation method for an electrode material and an electrolyte for a fuel cell, comprising the following steps:

[0035] (1) Mix the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery with a metal salt and / or an alkaline substance to obtain a first mixture;

[0036] (2) Perform a first sintering on the first mixture obtained in the step (1) to obtain the electrode material / electrolyte for a fuel cell;

[0037] Or,

[0038] 1) Mix the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery with an aqueous solution of a metal salt and / or an alkaline substance to obtain a second mixture;

[0039] 2) Perform a hydrothermal reaction on the second mixture obtained in the step 1) to obtain the electrode material / electrolyte for a fuel cell;

[0040] Or,

[0041] I. Mix the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery with a leaching agent, perform leaching to obtain a leachate;

[0042] II. Mix the leachate obtained in the step I with a metal salt and / or an alkaline substance to obtain a third mixture;

[0043] III. Perform gelation and a second sintering on the third mixture obtained in the step II in sequence to obtain the electrode material / electrolyte for a fuel cell;

[0044] The metal salt is at least one of lithium salt, sodium salt, potassium salt, nickel salt, cobalt salt and manganese salt; the alkaline substance is at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, nickel hydroxide, cobalt hydroxide and manganese hydroxide.

[0045] The present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0046] In one technical solution of the present invention, the method for preparing the electrode material and electrolyte for the fuel cell comprises the following steps:

[0047] (1) mixing an electrode material of a waste lithium ion battery / a solid electrolyte of a waste lithium ion battery with a metal salt and / or an alkaline substance to obtain a first mixed substance;

[0048] (2) The first mixed material obtained in step (1) is subjected to a first sintering to obtain an electrode material / electrolyte for a fuel cell.

[0049] The present invention mixes the electrode material of waste lithium ion batteries / solid electrolyte of waste lithium ion batteries with metal salts and / or alkaline substances to obtain a first mixed substance.

[0050] In the present invention, the electrode material of the waste lithium-ion battery preferably includes at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganate, nickel cobalt manganate, nickel cobalt aluminum oxide, lithium iron phosphate, lithium ferrite, lithium titanate, lithium cobalt aluminum oxide, lithium vanadate, doped lithium cobalt oxide, doped lithium nickel oxide, doped lithium manganate, doped lithium nickel cobalt manganate, doped lithium nickel cobalt aluminum oxide, doped lithium iron phosphate, doped lithium ferrite, doped lithium titanate, doped lithium cobalt aluminum oxide and doped lithium vanadate.

[0051] In the present invention, the solid electrolyte of the waste lithium-ion battery preferably includes one of an oxide solid electrolyte, a sulfide solid electrolyte, a polymer solid electrolyte and a composite solid electrolyte; the oxide solid electrolyte preferably includes at least one of lithium lanthanum zirconium oxide, lithium aluminum germanium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, tantalum-doped lithium lanthanum zirconium oxide, lithium aluminum titanium phosphate, lithium aluminum titanium phosphate and lithium zirconium silicon phosphorus oxide; the sulfide solid electrolyte preferably includes at least one of lithium sulfide, lithium oxysulfide phosphorus and β-lithium aluminum sulfide; the polymer solid electrolyte preferably includes a mixture of at least one of polyethylene oxide, polyethylene fluoride and polyacrylonitrile and a lithium salt; the lithium salt is preferably LiClO 4 、LiPF 6 and LiBF 4 At least one of; the composite solid electrolyte preferably includes a mixture of an oxide solid electrolyte / sulfide solid electrolyte and a polymer solid electrolyte.

[0052] In the present invention, the electrode material of waste lithium-ion batteries / solid electrolyte of waste lithium-ion batteries is preferably prepared by heat treatment, physical scraping, solvent dissolution or alkaline solution dissolution.

[0053] The present invention does not have special limitations on the specific operations of the heat treatment method, physical scraping method, solvent dissolution method, and alkali solution dissolution method, as long as the electrode materials of waste lithium-ion batteries and the solid electrolytes of waste lithium-ion batteries can be obtained.

[0054] In the present invention, the metal salt is at least one of lithium salts, sodium salts, potassium salts, nickel salts, cobalt salts, and manganese salts; the alkaline substance is at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, nickel hydroxide, cobalt hydroxide, and manganese hydroxide. The present invention utilizes metal ions (at least one of lithium ions, sodium ions, potassium ions, nickel ions, cobalt ions, and manganese ions) to supplement the performance of the electrode materials and solid electrolytes, thereby improving their performance.

[0055] In the present invention, the lithium salt preferably includes at least one of lithium carbonate, lithium fluoride, lithium chloride, lithium acetate, and lithium nitrate; the sodium salt preferably includes at least one of sodium carbonate, sodium fluoride, sodium chloride, sodium acetate, and sodium nitrate; the potassium salt preferably includes at least one of potassium carbonate, potassium fluoride, potassium chloride, potassium acetate, and potassium nitrate; the nickel salt preferably includes nickel carbonate and / or nickel nitrate; the cobalt salt preferably includes cobalt carbonate and / or cobalt nitrate; the manganese salt preferably includes manganese carbonate and / or manganese nitrate.

[0056] The present invention does not have special limitations on the operation of mixing the electrode materials / solid electrolytes of waste lithium-ion batteries with metal salts and / or alkaline substances, and the technical solutions for preparing the mixed materials well-known to those skilled in the art can be adopted.

[0057] In the present invention, the mass content of the electrode materials / solid electrolytes of waste lithium-ion batteries in the first mixed substance is preferably 20-99%. As an implementation manner, the mass content of the electrode materials / solid electrolytes of waste lithium-ion batteries in the first mixed substance can be 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 95%. The present invention limits the mass content of the electrode materials / solid electrolytes of waste lithium-ion batteries in the first mixed substance within the above range, which can further improve the performance of the electrode materials and solid electrolytes.

[0058] After obtaining the first mixed substance, the present invention subjects the first mixed substance to the first sintering to obtain the electrode materials / electrolytes for fuel cells.

[0059] In the present invention, the temperature of the first sintering is preferably 100 - 1500 °C; the time of the first sintering is preferably 1 - 20 h. As an implementation manner, the temperature of the first sintering can be 300 - 1200 °C, and can also be 500 - 800 °C; the time of the first sintering can be 4 - 18 h, and can also be 5 - 15 h. The present invention uses the first sintering to improve the performance of the electrode material and the electrolyte; limiting the temperature and time of the first sintering within the above ranges can further improve the performance of the electrode material and the electrolyte.

[0060] After the first sintering is completed, the present invention preferably cools and grinds the product obtained by the first sintering in sequence to obtain the electrode material / electrolyte for fuel cells.

[0061] The present invention has no special limitation on the cooling operation, and it can be cooled to room temperature.

[0062] The present invention has no special limitation on the grinding operation, and it can be adjusted according to actual needs.

[0063] Or after the first sintering is completed, the present invention preferably cools and washes the product obtained by the first sintering in sequence to obtain a washed product;

[0064] Mix the washed product with an additive to obtain a mixture;

[0065] Sinter the mixture, cool it for the second time, and grind it in sequence to obtain the electrode material / electrolyte for fuel cells.

[0066] The present invention has no special limitation on the first cooling operation, and it can be cooled to room temperature by using an operation well-known to those skilled in the art.

[0067] The present invention has no special limitation on the washing operation, and it can be washed until it is neutral.

[0068] In the present invention, the first additive preferably includes an alkali metal salt and / or a hydroxide.

[0069] In the present invention, the alkali metal salt is preferably at least one of a lithium salt, a sodium salt, and a potassium salt; the lithium salt preferably includes at least one of lithium carbonate, lithium fluoride, lithium chloride, lithium acetate, and lithium nitrate; the sodium salt preferably includes at least one of sodium carbonate, sodium fluoride, sodium chloride, sodium acetate, and sodium nitrate; the potassium salt preferably includes at least one of potassium carbonate, potassium fluoride, potassium chloride, potassium acetate, and potassium nitrate; the hydroxide is at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, nickel hydroxide, cobalt hydroxide, and manganese hydroxide. The present invention utilizes lithium ions, sodium ions, potassium ions, nickel ions, or manganese ions to further supplement the performance of the electrode material and the solid electrolyte, thereby further improving their performance.

[0070] In the present invention, the mass of the first additive is preferably 1-20% of the mass of the laundry. As an embodiment, the mass of the first additive can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or 19% of the mass of the laundry.

[0071] The present invention has no special limitation on the operation of mixing the laundry and the first additive, as long as the raw materials are mixed evenly.

[0072] In the present invention, the third sintering is preferably the same as the aforementioned first sintering operation, and will not be elaborated here.

[0073] The present invention has no special limitation on the operation of the second cooling, and it can be cooled to room temperature by using the operations well-known to those skilled in the art.

[0074] The present invention has no special limitation on the operation of the grinding, and the operations well-known to those skilled in the art can be used.

[0075] In one technical solution of the present invention, a method for preparing an electrode material and an electrolyte for a fuel cell includes the following steps:

[0076] 1) Mixing the electrode material of a waste lithium-ion battery / solid electrolyte of a waste lithium-ion battery with an aqueous solution of a metal salt and / or an alkaline substance to obtain a second mixture;

[0077] 2) Subjecting the second mixture obtained in step 1) to a hydrothermal reaction to obtain an electrode material / electrolyte for a fuel cell.

[0078] The present invention mixes the electrode material of a waste lithium-ion battery / solid electrolyte of a waste lithium-ion battery with an aqueous solution of a metal salt and / or an alkaline substance to obtain a second mixture.

[0079] In the present invention, the electrode material of the waste lithium-ion battery / solid electrolyte of the waste lithium-ion battery is the same as the aforementioned, and will not be elaborated here.

[0080] In the present invention, the concentration of the aqueous solution of the metal salt and / or the alkaline substance is preferably 0.01-6 mol / L. As an embodiment, the concentration of the aqueous solution of the metal salt and / or the alkaline substance can be 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L or 5 mol / L.

[0081] In the present invention, the molar ratio of the metal ions in the metal salt to the transition metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery is preferably (0.1 to 1):1; the molar ratio of the alkali metal ions in the alkaline substance to the transition metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery is preferably (0.1 to 1):1. Limiting the molar ratio of the metal ions in the metal salt to the transition metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery and the molar ratio of the alkali metal ions in the alkaline substance to the transition metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery within the above ranges can further improve the performance of the electrode material and the solid electrolyte.

[0082] As an embodiment, the molar ratio of the metal ions in the metal salt to the transition metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery can be (0.2 to 0.8):1, and can also be 0.4:1, 0.5:1 or 0.6:1; the molar ratio of the alkali metal ions in the alkaline substance to the transition metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery can be (0.2 to 0.8):1, and can also be 0.4:1, 0.5:1 or 0.6:1.

[0083] The present invention has no special limitation on the operation of mixing the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery with the aqueous solution of the metal salt and / or the alkaline substance, and the technical solutions for preparing the mixed material well-known to those skilled in the art can be adopted.

[0084] After obtaining the second mixed substance, the present invention performs a hydrothermal reaction on the second mixed substance to obtain the electrode material / electrolyte for the fuel cell.

[0085] In the present invention, the temperature of the hydrothermal reaction is preferably 80 to 240 °C; the time of the hydrothermal reaction is preferably 1 to 20 h. As an embodiment, the temperature of the hydrothermal reaction can be 100 to 220 °C, and can also be 140 to 180 °C; the time of the hydrothermal reaction can be 2 to 18 h, and can also be 5 to 15 h.

[0086] After the hydrothermal reaction is completed, the present invention preferably filters, washes, dries and grinds the product obtained from the hydrothermal reaction to obtain the electrode material / electrolyte for the fuel cell.

[0087] The present invention has no special limitation on the filtration operation, and the filtration operation well-known to those skilled in the art can be adopted to obtain the precipitate.

[0088] The present invention has no special limitation on the operation of the washing, as long as the precipitate is washed clean.

[0089] The present invention has no special limitation on the operation of the drying, and it can be dried to a constant weight.

[0090] The present invention has no special limitation on the operation of the grinding, and it can be selected according to actual needs.

[0091] Alternatively, after the hydrothermal reaction is completed, the present invention preferably filters and washes the product obtained from the hydrothermal reaction in sequence to obtain a washed product;

[0092] Mix the washed product with a second additive to obtain a mixed material;

[0093] Sinter the mixed material in sequence for the fourth time, cool it, and grind it to obtain an electrode material / electrolyte for a fuel cell.

[0094] The present invention has no special limitation on the operation of the filtration, and a filtration operation well-known to those skilled in the art can be adopted to obtain a precipitate.

[0095] The present invention has no special limitation on the operation of the washing, as long as the precipitate is washed clean.

[0096] In the present invention, the second additive is preferably the same as the first additive, which will not be elaborated here. The present invention utilizes lithium ions, sodium ions, potassium ions, nickel ions or manganese ions in the second additive to make up for the loss of metal ions during the sintering process, and further supplement the performance of the electrode material and the solid electrolyte, thereby further improving their performance.

[0097] In the present invention, the mass of the second additive is preferably 1-50% of the mass of the washed product. As an implementation manner, the mass of the second additive can be 5-10% of the mass of the washed product.

[0098] The present invention has no special limitation on the operation of mixing the washed product with the second additive, and a technical solution for preparing a mixed material well-known to those skilled in the art can be adopted.

[0099] In the present invention, the fourth sintering is preferably the same as the aforementioned first sintering, which will not be elaborated here. The present invention adopts the fourth sintering to further restore the structure of the electrode material and the electrolyte.

[0100] The present invention has no special limitation on the operation of the cooling, and a cooling operation well-known to those skilled in the art can be adopted.

[0101] The present invention has no special limitation on the operation of the grinding, and it can be selected according to actual needs.

[0102] In one technical solution of the present invention, the method for preparing the electrode material and electrolyte for a fuel cell includes the following steps:

[0103] I. Mix the electrode material of a waste lithium-ion battery / the solid electrolyte of a waste lithium-ion battery with a leaching agent, and perform leaching to obtain a leachate.

[0104] II. Mix the leachate obtained in step I with a metal salt and / or an alkaline substance to obtain a third mixture.

[0105] III. Subject the third mixture obtained in step II to gelation and second sintering in sequence to obtain the electrode material / electrolyte for a fuel cell.

[0106] The present invention mixes the electrode material of a waste lithium-ion battery / the solid electrolyte of a waste lithium-ion battery with a leaching agent, and performs leaching to obtain a leachate.

[0107] In the present invention, the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery is the same as described above, and will not be elaborated here.

[0108] In the present invention, the leaching agent preferably includes one of citric acid, lactic acid, malic acid, hydrochloric acid, and nitric acid; the concentration of the leaching agent is preferably 0.5 - 8 mol / L; the mass ratio of the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery to the volume of the leaching agent is preferably (10 - 30) g:1 L. The present invention uses the leaching agent to leach the metal ions in the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery, which is beneficial for subsequent mixing with the metal salt and / or the alkaline substance.

[0109] As an implementation manner, the concentration of the leaching agent can be 1.5 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, or 7 mol / L; the mass ratio of the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery to the volume of the leaching agent can be (12 - 25) g:1 L, or can also be (15 - 20) g:1 L.

[0110] The present invention has no special limitation on the operation of mixing the electrode material of the waste lithium-ion battery / the solid electrolyte of the waste lithium-ion battery with the leaching agent, and the technical solution for preparing the mixed material well-known to those skilled in the art can be adopted.

[0111] In the present invention, the temperature of the leaching is preferably 20 - 100 °C; the time of the leaching is preferably 20 - 360 min. The present invention limits the temperature and time of the leaching within the above ranges to further improve the leaching rate.

[0112] As an implementation manner, the temperature of the leaching can be 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C; the time of the leaching can be 30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, 240 min, 270 min, 300 min, 330 min or 360 min.

[0113] After obtaining the leaching solution, the present invention mixes the leaching solution with a metal salt and / or an alkaline substance to obtain a third mixture.

[0114] In the present invention, the metal salt is at least one of a lithium salt, a sodium salt, a potassium salt, a nickel salt, a cobalt salt and a manganese salt; the alkaline substance is at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, nickel hydroxide, cobalt hydroxide and manganese hydroxide.

[0115] In the present invention, the lithium salt preferably includes at least one of lithium carbonate, lithium fluoride, lithium chloride, lithium acetate and lithium nitrate; the sodium salt preferably includes at least one of sodium carbonate, sodium fluoride, sodium chloride, sodium acetate and sodium nitrate; the potassium salt preferably includes at least one of potassium carbonate, potassium fluoride, potassium chloride, potassium acetate and potassium nitrate; the nickel salt preferably includes nickel carbonate and / or nickel nitrate; the cobalt salt preferably includes cobalt carbonate and / or cobalt nitrate; the manganese salt preferably includes manganese carbonate and / or manganese nitrate.

[0116] In the present invention, the molar ratio of the metal ions in the metal salt to the transition metal ions in the leaching solution is preferably (0.6 - 1.4):1; the molar ratio of the metal ions in the alkaline substance to the transition metal ions in the leaching solution is preferably (0.6 - 1.4):1. Limiting the molar ratio of the metal ions in the metal salt to the transition metal ions in the leaching solution and the molar ratio of the metal ions in the alkaline substance to the transition metal ions in the leaching solution within the above ranges can further improve the performance of the electrode material and the solid electrolyte.

[0117] As an implementation manner, the molar ratio of the metal ions in the metal salt to the transition metal ions in the leaching solution can be (0.8 - 1.2):1; the molar ratio of the metal ions in the alkaline substance to the transition metal ions in the leaching solution can be (0.8 - 1.2):1.

[0118] The present invention has no special limitation on the operation of mixing the leaching solution with a metal salt and / or an alkaline substance, and a technical solution for preparing a mixed material well-known to those skilled in the art can be adopted.

[0119] After obtaining the third mixture, the present invention subjects the third mixture to gelation and secondary sintering in sequence to obtain an electrode material / electrolyte for a fuel cell.

[0120] In the present invention, the temperature of the gel is preferably 50 to 100 °C; the time of the gel is preferably 2 to 10 h; the gel is preferably carried out under stirring conditions. The present invention has no special limitation on the operation of the stirring, and the stirring operation well-known to those skilled in the art can be adopted.

[0121] As an embodiment, the temperature of the gel can be 60 °C, 70 °C, 80 °C or 90 °C; the time of the gel can be 3 h, 4 h, 5 h, 6 h, 7 h, 8 h or 9 h.

[0122] In the present invention, the pH value of the third mixture during the gel is preferably 7 to 9; the pH value of the third mixture is preferably adjusted with ammonia water. The present invention has no special limitation on the dosage of the ammonia water, as long as the pH value of the third mixture meets the above requirements.

[0123] After the gel is completed, the present invention preferably dries and grinds the gel precursor obtained from the gel in sequence.

[0124] In the present invention, the temperature of the drying is preferably 100 to 150 °C; the time of the drying is preferably 12 to 36 h. As an embodiment, the temperature of the drying can be 110 °C, 120 °C, 130 °C or 140 °C; the time of the drying can be 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, 32 h or 34 h.

[0125] The present invention has no special limitation on the operation of the grinding, and it can be selected according to actual needs.

[0126] In the present invention, the temperature of the second sintering is preferably 200 to 1500 °C; the time of the second sintering is preferably 2 to 20 h. As an embodiment, the temperature of the second sintering can be 300 to 1200 °C, and can also be 500 to 1000 °C; the time of the second sintering can be 5 to 18 h, and can also be 10 to 15 h.

[0127] After the second sintering is completed, the present invention preferably grinds the product obtained from the second sintering to obtain the electrode material / electrolyte for the fuel cell.

[0128] The present invention has no special limitation on the operation of the grinding, and it can be selected according to actual needs.

[0129] The present invention uses metal ions (at least one of lithium ions, sodium ions, potassium ions, nickel ions, cobalt ions, and manganese ions) to supplement the electrode materials of waste lithium-ion batteries, which can make up for the loss of metal ions in the electrode materials. After that, sintering or hydrothermal reaction is adopted to restore the structure of the electrode materials, thereby improving the structural stability and conductivity of the electrode materials; using metal ions (at least one of lithium ions, sodium ions, potassium ions, nickel ions, cobalt ions, and manganese ions) to supplement the solid electrolytes of waste lithium-ion batteries can make up for the loss of metal ions in the solid electrolytes. After that, sintering or hydrothermal reaction is adopted to restore the structure of the electrode materials, thereby optimizing the ionic conductivity and interfacial compatibility of the solid electrolytes, significantly improving the performance of the electrode materials and electrolytes, and further ensuring the performance of the fuel cell.

[0130] The present invention uses the electrode materials and solid electrolytes of waste lithium-ion batteries as raw materials to conduct research on direct regeneration technology modification. The direct regeneration technologies used (high-temperature solid-phase method, hydrothermal method, wet chemical method, and molten salt method) have the advantages of high recovery rate, simple operation, and low cost; the preparation method provided by the present invention can restore the electrode materials and solid electrolytes of waste lithium-ion batteries into high-value materials that can be used in fuel cells. This recycling method not only improves the resource utilization rate and reduces the environmental burden but also provides raw material support for the performance improvement of solid oxide fuel cells. This is of great significance for promoting the development of clean energy technologies and promoting sustainable development.

[0131] The preparation method provided by the present invention has significant environmental and economic benefits, significantly reduces the impact of waste lithium-ion batteries on the environment, realizes the effective recovery and reuse of resources, and provides high-performance electrode materials for the development of solid oxide fuel cells. In addition, this method can promote the circular economy of the lithium battery and fuel cell industries and promote the progress of sustainable energy technologies.

[0132] The present invention also provides the electrode materials and electrolytes for fuel cells prepared by the preparation method described in the above technical solution.

[0133] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0134] Example 1

[0135] A preparation method for an electrode material for a fuel cell comprises the following steps:

[0136] (1) Place the positive electrode sheet of the waste lithium-ion battery (NCML) in a 1.5 mol / L NaOH solution and soak it at room temperature for 5 h. Wash the precipitate obtained after soaking 4 times with deionized water, then filter it. The filtered material is dried at 120 °C for 24 h, and then ground by hand to obtain NCML powder;

[0137] (2) Grind and mix 3 g of the NCML powder obtained in the above step (1) with 0.75 g of sodium carbonate to obtain a mixture; among them, the mass content of the NCML powder in the mixture is 80%;

[0138] (3) Heat the mixture obtained in the above step (2) to 800 °C at a rate of 10 °C / min and sinter for 4 h, then cool it naturally, and then grind it to obtain the electrode material for fuel cells.

[0139] Example 2

[0140] A preparation method of an electrode material for fuel cells is as follows:

[0141] (1) Place the positive electrode sheet of the waste lithium-ion battery (NCML) in a 1.5 mol / L NaOH solution and soak it at room temperature for 5 h. Wash the precipitate obtained after soaking 4 times with deionized water, then filter it. The filtered material is dried at 120 °C for 24 h, and then ground by hand to obtain NCML powder;

[0142] (2) Grind and mix 3 g of the NCML powder obtained in the above step (1) with 0.75 g of lithium carbonate to obtain a mixture; among them, the mass content of the NCML powder in the mixture is 80%;

[0143] (3) Heat the mixture obtained in the above step (2) to 800 °C at a rate of 10 °C / min and sinter for 4 h, then cool it naturally, and then grind it to obtain the electrode material for fuel cells.

[0144] Figure 1 It is the refined X-ray diffraction pattern of the NCML powder obtained in steps (1) of Examples 1-2;

[0145] Figure 2 It is the refined X-ray diffraction pattern of the electrode material for fuel cells prepared in Example 2.

[0146] From Figures 1 - 2 It can be seen that the restored material (the electrode material for fuel cells) has a more stable crystal structure.

[0147] Figure 3IVP test chart of a fuel cell prepared using the NCML powder in Example 1 and the electrode material in Example 1; wherein, the test method is as follows: Mix the electrode material and terpineol in a mass ratio of 3:1 to make a slurry, and coat it on nickel foam to obtain the cathode and anode layers, and assemble it with Ce 0.8 Sm 0.2 O 1.9 (SDC) into a fuel cell. Then, preheat the fuel cell at 550 °C for 1 h, and then introduce 150 sccm of air and 100 sccm of hydrogen into the cathode and anode of the cell respectively, and use an IT8511 electronic load to test the performance of the fuel cell.

[0148] From Figure 3 It can be seen that the IVP performance of the fuel cell prepared using the electrode material in Example 1 has been significantly improved.

[0149] Figure 4 IVP test chart of a fuel cell prepared using the NCML powder in Example 2 and the electrode material in Example 2; wherein, the test method is as follows: Mix the electrode material and terpineol in a mass ratio of 3:1 to make a slurry, and coat it on nickel foam to obtain the cathode and anode layers, and assemble it with Ce 0.8 Sm 0.2 O 1.9 (SDC) into a fuel cell. Then, preheat the fuel cell at 550 °C for 1 h, and then introduce 150 sccm of air and 100 sccm of hydrogen into the cathode and anode of the cell respectively, and use an IT8511 electronic load to test the performance of the fuel cell.

[0150] From Figure 4 It can be seen that the IVP performance of the fuel cell prepared using the electrode material in Example 2 has been significantly improved.

[0151] Example 3

[0152] A preparation method of an electrode material for a fuel cell, comprising the following steps:

[0153] (1) Place the positive electrode plate of a waste lithium-ion battery (LiCoO 2 ) in a 1.5 mol / L NaOH solution and soak it at room temperature for 5 h. Wash the obtained precipitate with deionized water 4 times, then filter it, and dry the filtered material at 120 °C for 24 h, and then grind it by hand to obtain LiCoO 2 powder;

[0154] (2) Grind and mix 3 g of the LiCoO 2 powder obtained in step (1) with 0.75 g of sodium carbonate to obtain a mixture; wherein, the LiCoO in the mixture 2The mass content of the powder is 80%;

[0155] (3) Heat the mixture obtained in the step (2) to 800 °C at a rate of 10 °C / min and sinter for 4 h, then cool naturally, and then grind to obtain the electrode material for fuel cells.

[0156] Figure 5 It is the IVP test chart of the fuel cell prepared with the LiCoO 2 powder in Example 3 and the electrode material in Example 3; wherein, the test method is as follows: Mix the electrode material and terpineol in a mass ratio of 3:1 to form a slurry, and coat it on nickel foam to obtain the cathode and anode layers, and assemble it with Ce 0.8 Sm 0.2 O 1.9 (SDC) into a fuel cell. Then preheat the fuel cell at 550 °C for 1 h, and then introduce 150 sccm of air and 100 sccm of hydrogen into the cathode and anode of the cell respectively, and use an IT8511 electronic load to test the performance of the fuel cell.

[0157] From Figure 5 It can be seen that the IVP performance of the fuel cell prepared with the electrode material in Example 3 has been significantly improved.

[0158] The scanning electron microscope image of the electrode material for fuel cells prepared in Example 3 is as Figure 6 shown.

[0159] From Figure 6 it can be seen that the size of the electrode material particles is between 1 μm and 10 μm.

[0160] Example 4

[0161] A preparation method of an electrode material for fuel cells, which is the following steps:

[0162] (1) Place the positive electrode plate of the waste lithium-ion battery (NCML) in an N-methylpyrrolidone solution, and use an ultrasonic cleaner for separation. After that, wash the positive electrode material with ionized water, and then dry it at 120 °C for 24 h, and grind it to obtain NCML powder;

[0163] (2) Add the NCML powder obtained in the step (1) to the polytetrafluoroethylene inner liner of an autoclave containing 4 mol / L lithium hydroxide solution for mixing to obtain a mixture; wherein, the molar ratio of Li ions in lithium hydroxide to transition metal ions in NCML powder is 0.5:1;

[0164] (3) Carry out a hydrothermal reaction on the mixture obtained in the step (2) at 220 °C for 4 h, then filter, and then wash with deionized water to obtain a washed product;

[0165] (4) Add 5% of the mass of the washed material obtained in step (3) of Li 2 CO 3 , to obtain a mixed material;

[0166] (5) Heat the mixed material obtained in step (4) to 850 °C at a rate of 5 °C / min and sinter for 4 h, then cool naturally, and then grind to obtain the electrode material for fuel cells.

[0167] Figure 7 is the IVP test chart of the fuel cell prepared using the NCML powder in Example 4 and the electrode material in Example 4; among them, the test method is as follows: Mix the electrode material and terpineol in a mass ratio of 3:1 to make a slurry, and coat it on nickel foam to obtain the cathode and anode layers, and assemble it with Ce 0.8 Sm 0.2 O 1.9 (SDC) into a fuel cell, then preheat the fuel cell at 550 °C for 1 h, and then introduce 150 sccm of air and 100 sccm of hydrogen into the cathode and anode of the cell respectively, and use an IT8511 electronic load to test the performance of the fuel cell.

[0168] From Figure 7 it can be seen that the IVP performance of the fuel cell prepared using the electrode material in Example 4 has been significantly improved.

[0169] Example 5

[0170] A preparation method of an electrode material for a fuel cell, comprising the following steps:

[0171] (1) Place the positive electrode sheet of a waste lithium-ion battery (NCML) in an N-methylpyrrolidone solution, and use an ultrasonic cleaner to separate it. After that, wash the positive electrode material with ionized water, then dry it at 120 °C for 24 h, and grind it to obtain NCML powder;

[0172] (2) Add the NCML powder obtained in step (1) to a 100 mL polytetrafluoroethylene inner liner of an autoclave containing a 4 mol / L lithium hydroxide solution for mixing to obtain a mixture; among them, the molar ratio of Li ions in lithium hydroxide to transition metal ions in the NCML powder is 0.5:1;

[0173] (3) Carry out a hydrothermal reaction on the mixture obtained in step (2) at 220 °C for 4 h, then filter, then wash and dry with deionized water, and then grind to obtain the electrode material for fuel cells.

[0174] Example 6

[0175] A method for preparing an electrode material for a fuel cell comprises the following steps:

[0176] (1) The electrode sheets from waste lithium-ion batteries (NCML) were sintered at 200° C. for 30 min, and then filtered and ground in sequence to obtain NCML powder;

[0177] (2) The NCML powder obtained in step (1) was mixed with LiNO 3 and LiOH to obtain a mixed substance; among which LiNO 3 The molar ratio of NCML to LiOH is 3:2; the mass content of NCML powder in the mixed material is 80%;

[0178] (3) heating the mixed material obtained in step (2) to 850° C. at a rate of 3° C. / min and sintering for 8 h, cooling the mixed material and washing it with deionized water to obtain a washed material;

[0179] (4) adding lithium carbonate in an amount of 10% by weight of the washing material to the washing material obtained in step (3), grinding and mixing the mixture to obtain a mixture;

[0180] (5) The mixture obtained in step (4) is heated to 800° C. at a rate of 10° C. / min and sintered for 4 h, then naturally cooled, and subsequently ground to obtain an electrode material for a fuel cell.

[0181] Figure 8 The IVP test diagram of the fuel cell prepared by using the NCML powder and the electrode material of Example 6; wherein the test method is as follows: the electrode material and pine alcohol are mixed in a mass ratio of 3:1 to form a slurry, and the slurry is coated on the nickel foam to obtain the cathode and anode layers, and Ce 0.8 Sm 0.2 O 1.9 The SDC was assembled into a fuel cell, and then the fuel cell was preheated at 550°C for 1h. Then, 150sccm of air and 100sccm of hydrogen were introduced into the cathode and anode of the battery respectively, and the performance of the fuel cell was tested using an IT8511 electronic load.

[0182] from Figure 8 It can be seen that the IVP performance of the fuel cell prepared using the electrode material of Example 6 is significantly improved.

[0183] Example 7

[0184] A method for preparing an electrode material for a fuel cell comprises the following steps:

[0185] (1) Use a knife to remove the waste lithium-ion battery electrode sheet (LiCoO 2 ) is scraped off from the aluminum foil and then fully ground to obtain LiCoO2 Powder;

[0186] (2) Mix the LiCoO powder obtained in step (1) with citric acid, and perform leaching at 80 °C for 60 min to obtain a leaching solution; wherein, the concentration of citric acid is 1.5 mol / L, and the mass-to-volume ratio of the LiCoO powder to the volume of citric acid is 20 g / L; 2 powder and citric acid, and carry out leaching at 80 °C for 60 min to obtain a leaching solution; where the concentration of citric acid is 1.5 mol / L, and the mass-to-volume ratio of the LiCoO powder to the volume of citric acid is 20 g / L; 2 The mass-to-volume ratio of the powder to the volume of citric acid is 20 g / L;

[0187] (3) Add lithium acetate to the leaching solution obtained in step (2) to obtain a mixture, where the molar ratio of Li ions in lithium acetate to transition metal ions in the leaching solution is 1.1:1;

[0188] (4) Add ammonia water to the mixture obtained in step (3) to adjust the pH value to 7, and at the same time stir at 100 °C for 6 h to obtain a gel, then dry in a vacuum drying oven at 150 °C for 24 h, then grind, and sinter in an air atmosphere at 700 °C for 6 h, and then grind to obtain an electrode material for a fuel cell.

[0189] Example 8

[0190] A method for preparing a solid electrolyte for a fuel cell, which is the following steps:

[0191] (1) Remove the solid electrolyte lithium lanthanum zirconium oxide from the waste lithium-ion battery, then wash it with ethanol for 20 min and dry it, and use a hammering method to break the solid electrolyte and grind it into a uniform powder to obtain a solid electrolyte powder;

[0192] (2) Grind and mix the solid electrolyte powder obtained in step (1) with lithium carbonate to obtain a mixture; wherein, the mass content of the solid electrolyte powder in the mixture is 75%;

[0193] (3) Heat the mixture obtained in step (2) to 800 °C at a rate of 10 °C / min, sinter for 4 h, then cool naturally, and then grind to obtain a solid electrolyte for a fuel cell.

[0194] Example 9

[0195] A method for preparing a solid electrolyte for a fuel cell, which is the following steps:

[0196] (1) Remove the solid electrolyte lithium lanthanum titanium oxide from the waste lithium-ion battery, then wash it with ethanol for 20 min and dry it, and use a hammering method to break the solid electrolyte and grind it into a uniform powder to obtain a solid electrolyte powder;

[0197] (2) Add the solid electrolyte powder obtained in step (1) to a 100 mL polytetrafluoroethylene inner liner of an autoclave containing a 4 mol / L lithium hydroxide solution for mixing to obtain a mixture; wherein, the molar ratio of Li ions in lithium hydroxide to transition metal ions in the NCML powder is 0.5:1;

[0198] (3) Hydrothermally react the mixture obtained in step (2) at 500 °C for 6 h, then filter, and then wash with deionized water to obtain a washed product;

[0199] (4) Add Li 2 CO 3 to the washed product obtained in step (3) in an amount of 10% of the mass of the washed product to obtain a mixed material;

[0200] (5) Heat the mixed material obtained in step (4) to 800 °C at a rate of 5 °C / min and sinter for 6 h, then cool naturally, and then grind to obtain a solid electrolyte for fuel cells.

[0201] Example 10

[0202] A preparation method of a solid electrolyte for fuel cells comprises the following steps:

[0203] (1) Remove the solid electrolyte lithium lanthanum zirconium oxide from the waste lithium-ion battery, then wash it with ethanol for 20 min and dry it, and use a hammering method to break the solid electrolyte and grind it into a uniform powder to obtain a solid electrolyte powder;

[0204] (2) Mix the solid electrolyte powder obtained in step (1) with citric acid and leach at 30 °C for 150 min to obtain a leachate; wherein, the concentration of citric acid is 3.5 mol / L, and the mass ratio of the solid electrolyte powder to the volume of citric acid is 25 g / L;

[0205] (3) Add lithium acetate to the leachate obtained in step (2) to obtain a mixture, wherein the molar ratio of Li ions in lithium acetate to transition metal ions in the leachate is 0.6:1;

[0206] (4) Add ammonia water to the mixture obtained in step (3) to adjust the pH value to 7, and stir at 50 °C for 10 h to obtain a gel, then dry it in a vacuum drying oven at 150 °C for 24 h, grind it again, and sinter it at 1200 °C in an air atmosphere for 2 h, and then grind it to obtain a solid electrolyte for fuel cells.

[0207] As can be seen from the above examples, the preparation method provided by the present invention can improve the performance of the electrode material and electrolyte for fuel cells, thereby ensuring the performance of the battery.

[0208] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing an electrode material and an electrolyte for a fuel cell, comprising the following steps: (1) mixing an electrode material of a waste lithium ion battery / a solid electrolyte of a waste lithium ion battery with a metal salt and / or an alkaline substance to obtain a first mixed substance; (2) performing a first sintering on the first mixed material obtained in step (1) to obtain an electrode material / electrolyte for a fuel cell; or, 1) mixing the electrode material of the waste lithium ion battery / the solid electrolyte of the waste lithium ion battery with the aqueous solution of the metal salt and / or the alkaline substance to obtain a second mixed substance; 2) subjecting the second mixed substance obtained in step 1) to a hydrothermal reaction to obtain an electrode material / electrolyte for a fuel cell; or, 1. Mixing the electrode material of waste lithium ion batteries / solid electrolyte of waste lithium ion batteries with a leaching agent, leaching, and obtaining a leachate; II. mixing the leachate obtained in step I with a metal salt and / or an alkaline substance to obtain a third mixed substance; III. performing gelation and second sintering on the third mixed substance obtained in step II in sequence to obtain an electrode material / electrolyte for a fuel cell; The metal salt is at least one of lithium salt, sodium salt, potassium salt, nickel salt, cobalt salt and manganese salt; the alkaline substance is at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, nickel hydroxide, cobalt hydroxide and manganese hydroxide.

2. The preparation method according to claim 1, characterized in that: The electrode material of the waste lithium ion battery in the step (1), the electrode material of the waste lithium ion battery in step 1) and the electrode material of the waste lithium ion battery in step I independently include at least one of lithium cobaltate, lithium nickelate, lithium manganate, nickel cobalt lithium manganate, nickel cobalt aluminum oxide, lithium iron phosphate, lithium ferrite, lithium titanate, lithium cobalt aluminum oxide, lithium vanadate, doped lithium cobaltate, doped lithium nickelate, doped lithium manganate, doped lithium nickel cobalt manganate, doped lithium nickel cobalt aluminum oxide, doped lithium iron phosphate, doped lithium ferrite, doped lithium titanate, doped lithium cobalt aluminum oxide and doped lithium vanadate.

3. The preparation method according to claim 1, characterized in that: The solid electrolyte of the waste lithium ion battery in step (1), the solid electrolyte of the waste lithium ion battery in step 1) and the solid electrolyte of the waste lithium ion battery in step I independently include one of an oxide solid electrolyte, a sulfide solid electrolyte, a polymer solid electrolyte and a composite solid electrolyte.

4. The preparation method according to claim 1, characterized in that: In the step (1), the mass content of the electrode material of the waste lithium ion battery / the solid electrolyte of the waste lithium ion battery in the first mixed substance is 20-99%.

5. The preparation method according to claim 1, characterized in that: In the step (2), the temperature of the first sintering is 100 to 1500° C., and the time of the first sintering is 1 to 20 hours.

6. The preparation method according to claim 1, characterized in that: In the step 1), the molar ratio of the metal ions in the metal salt to the transition metal ions in the electrode material of the waste lithium ion battery / the solid electrolyte of the waste lithium ion battery is (0.1-1):1; the molar ratio of the alkali metal ions in the alkaline substance to the transition metal ions in the electrode material of the waste lithium ion battery / the solid electrolyte of the waste lithium ion battery is (0.1-1):

1.

7. The preparation method according to claim 1, characterized in that: The temperature of the hydrothermal reaction in step 2) is 80 to 240° C., and the time of the hydrothermal reaction is 1 to 20 hours.

8. The preparation method according to claim 1, characterized in that: The leaching agent in step I includes one of citric acid, lactic acid, malic acid, hydrochloric acid and nitric acid.

9. The preparation method according to claim 1, characterized in that: The temperature of the second sintering in step III is 200-1500° C., and the time of the second sintering is 2-20 hours.

10. An electrode material and an electrolyte for a fuel cell prepared by the preparation method according to any one of claims 1 to 9.

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