A short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material

Abstract

The present disclosure provides a short-term regeneration method for waste nickel-cobalt-manganese oxide positive electrode materials, relating to the field of waste battery regeneration technology. The method comprises: separating black powder from waste nickel-cobalt-manganese oxide batteries; mixing the black powder with a mixture consisting of an acid, a reducing agent, and a surfactant for acid leaching to obtain a leachate, which is then filtered to obtain a purified liquid; wherein the surfactant is sodium dodecyl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:(1-3); spray pyrolysis of the purified liquid to obtain nickel-cobalt-manganese oxide lithium powder, and adding lithium carbonate to the nickel-cobalt-manganese oxide powder for sintering to obtain a regenerated nickel-cobalt-manganese oxide lithium positive electrode material. The present disclosure improves the leaching rate by adding a specific proportion of surfactant, while also refining the grain size of the material's 003 crystal plane, increasing the crystal plane activity and improving the capacity.

Description

Technical Field

[0001] The present disclosure relates to the technical field of waste battery regeneration, and in particular to a short-range regeneration method for waste nickel-cobalt-manganese-oxide lithium positive electrode materials. Background Art

[0002] In recent years, the scale of my country's new energy market has continued to expand, and the sales of lithium-ion batteries have grown rapidly, resulting in the generation of a large number of retired lithium-ion batteries and causing serious environmental pollution. The metal resources contained in waste lithium-ion batteries are of high value. Recycling metals through more efficient methods can solve serious environmental pollution and alleviate resource shortages. In addition, it is particularly important to use quick and easy methods to prepare resources into products again.

[0003] However, the ternary material leaching rate obtained by the current regeneration method is poor and the grain size of the 003 crystal surface is large, which makes it impossible to obtain good capacity.

[0004] In view of this, the present disclosure is proposed. Summary of the Invention

[0005] The purpose of the present disclosure is to provide a short-term regeneration method for waste nickel cobalt manganese oxide positive electrode materials, which improves the input and output rate through the compounded surfactant, and the residual surfactant can refine the grain size of the material 003 crystal surface during the subsequent sintering process, increase the crystal surface activity, and improve the capacity.

[0006] The present disclosure is achieved as follows:

[0007] In a first aspect, the present disclosure provides a short-range regeneration method for waste lithium nickel cobalt manganese oxide positive electrode materials, comprising:

[0008] Separating a positive electrode active material from a waste lithium nickel cobalt manganese oxide battery, and calcining the positive electrode active material to remove PVDF and a binder to obtain a black powder;

[0009] A mixture of an acid, a reducing agent, and a surfactant is mixed with the black powder for acid leaching to obtain a leachate, which is filtered to obtain a purified liquid; wherein the surfactant is sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:(1-3);

[0010] The purified liquid is spray-pyrolyzed to obtain nickel-cobalt-manganese lithium oxide powder, and lithium carbonate is added to the nickel-cobalt-manganese lithium oxide powder for sintering to obtain a regenerated nickel-cobalt-manganese lithium oxide positive electrode material.

[0011] In an optional embodiment, the solid-to-liquid ratio of the black powder to the mixed liquid is 40 g / L to 120 g / L.

[0012] In an optional embodiment, the concentration of the surfactant in the mixed solution is 1 vol% to 5 vol%.

[0013] In an optional embodiment, the hydrogen ion concentration of the acid in the mixed solution is 0.5 mol / L to 2 mol / L.

[0014] In an optional embodiment, the acid includes any one or a combination of multiple ones of hydrochloric acid, sulfuric acid, nitric acid, malic acid and citric acid.

[0015] In an optional embodiment, the concentration of the reducing agent in the mixed solution is 1 vol% to 10 vol%.

[0016] In an optional embodiment, the reducing agent includes any one or a combination of more than one of hydrogen peroxide, sodium sulfite and glucose.

[0017] In an optional embodiment, the temperature during the acid leaching is 60° C. to 80° C., and the acid leaching time is 4 h to 8 h.

[0018] In an optional embodiment, stirring is continued during the acid leaching process.

[0019] In an optional embodiment, the purified liquid is dried with hot air at a temperature of 200° C. to 800° C. during the spray pyrolysis.

[0020] In an optional embodiment, the spray pyrolysis includes a first temperature zone, a second temperature zone and a third temperature zone arranged in sequence from top to bottom, the temperature of the first temperature zone is 200°C to 300°C, the temperature of the second temperature zone is 400°C to 500°C; the temperature of the third temperature zone is 600°C to 800°C, and a nozzle for introducing the purification liquid is provided at the top of the first temperature zone.

[0021] In an optional embodiment, the flow rate of the purified liquid during the spray pyrolysis is 4L / h to 12L / h, and the flow rate of the hot air is 4m 3 / L~8m 3 / L.

[0022] In an optional embodiment, the acid gas carried in the hot air after the spray pyrolysis is collected and then acidified to form recovered acid, and the recovered acid is returned to the mixed liquid for reuse.

[0023] In an optional embodiment, the amount of lithium carbonate added is 4-6% of the mass of the nickel-cobalt-manganese lithium oxide powder.

[0024] In an optional embodiment, the sintering temperature is 700° C. to 900° C., and the sintering time is 10 h to 20 h.

[0025] In an optional embodiment, the method for separating the positive electrode active material includes: immersing the waste nickel cobalt manganese oxide battery in a salt solution for discharge, disassembling it after the discharge is completed, separating the positive electrode sheet, placing the positive electrode sheet in an NMP solution heated to 60°C to 75°C for 5min to 15min, allowing the positive electrode active material to fall off, rinsing with deionized water, and drying to obtain the product.

[0026] In an optional embodiment, the saline solution is a 2 mol / L to 8 mol / L sodium chloride saline solution.

[0027] In an optional embodiment, the soaking time is 4 hours to 6 hours.

[0028] In an optional embodiment, the calcination includes calcining at 600° C. to 750° C. for 4 h to 6 h.

[0029] In an optional embodiment, the 003 crystal plane grain size of the regenerated lithium nickel cobalt manganese oxide positive electrode material is 400 angstroms to 420 angstroms.

[0030] The present disclosure has the following beneficial effects:

[0031] In the present disclosure, a surfactant is added by mixing sodium dodecyl sulfate and hexadecyltrimethylammonium bromide in a specific proportion. The addition of the surfactant greatly improves the leaching rate of the process. In addition, the present disclosure is different from the existing conventional solution of adding a surfactant to change the morphology of the prepared precursor and reduce the external particle size of the material itself. The present disclosure does not need to prepare the nickel-cobalt-manganese lithium hydroxide precursor by the conventional co-precipitation method on the purified liquid after leaching. Instead, the purified liquid is directly spray-pyrolyzed to obtain nickel-cobalt-manganese lithium oxide powder. At the same time, there is no washing process, so that the surfactant remains on the surface of the nickel-cobalt-manganese lithium oxide powder. Subsequently, during the sintering process, the surfactant remaining on the surface of the nickel-cobalt-manganese lithium oxide powder can refine the grain size of the material 003 crystals, increase the crystal surface activity, and improve the capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 A process flow chart of a short-range regeneration method for waste nickel-cobalt-lithium manganese oxide positive electrode materials provided by the present disclosure;

[0034] Figure 2XRD characterization of the ternary cathode material prepared in Example 1 of the present disclosure;

[0035] Figure 3 This is a process flow chart provided for Comparative Example 6 of the present disclosure. DETAILED DESCRIPTION

[0036] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0037] The present disclosure provides a short-range regeneration method for waste lithium nickel cobalt manganese oxide positive electrode materials, which comprises:

[0038] Separating the positive electrode active material from the waste lithium nickel cobalt manganese oxide battery, calcining the positive electrode active material to remove PVDF and binder to obtain black powder;

[0039] A mixture of acid, a reducing agent, and a surfactant is mixed with the black powder for acid leaching to obtain a leachate, which is filtered to obtain a purified liquid; wherein the surfactant is sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:(1-3);

[0040] The purified liquid is spray-pyrolyzed to obtain nickel-cobalt-manganese lithium oxide powder, and lithium carbonate is added to the nickel-cobalt-manganese lithium oxide powder for sintering to obtain regenerated nickel-cobalt-manganese lithium oxide positive electrode material.

[0041] In the present disclosure, by adding a specific surfactant during the acid leaching process, not only can the leaching rate of the acid leaching process be greatly improved, but also because the present disclosure only filters the leachate, the purified liquid still contains a surfactant, which will partially remain on the surface of the nickel-cobalt-manganese lithium oxide powder during the subsequent spray pyrolysis. This residual surfactant can refine the grain size of the material's 003 crystal surface during sintering, increase the crystal surface activity, and improve the capacity.

[0042] Next, see Figure 1 , this disclosure will elaborate on the above steps in detail:

[0043] S1. Black powder is obtained by processing waste nickel cobalt manganese oxide lithium batteries.

[0044] Used lithium nickel cobalt manganese oxide batteries were immersed in a salt solution for 4 to 6 hours and discharged to below 1V. After discharge, they were manually disassembled to separate the positive electrode sheets. The positive electrode sheets were then placed in an NMP solution heated to 60°C to 75°C for 5 to 15 minutes to allow the positive electrode active material to fall off. The positive electrode active material was then rinsed with deionized water and dried to obtain the positive electrode active material. The positive electrode active material was calcined at 600°C to 750°C for 4 to 6 hours to remove the PVDF and binder, resulting in a black powder.

[0045] The salt solution is a 2 mol / L to 8 mol / L sodium chloride salt solution. In some embodiments, the concentration of the sodium chloride salt solution can also be any one of 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, or a range between any two of them.

[0046] S2. Acid leaching to obtain purified liquid.

[0047] A mixture of an acid, a reducing agent, and a surfactant is prepared, wherein the acid has a hydrogen ion concentration of 0.5 mol / L to 2 mol / L, the reducing agent has a concentration of 1 vol% to 10 vol%, and the surfactant has a concentration of 1 vol% to 5 vol%. In some embodiments, the acid concentration can be, for example, any one of 0.5 mol / L, 1 mol / L, 1.5 mol / L, and 2 mol / L, or a range between any two of them; the reducing agent concentration can be, for example, any one of 1 vol%, 2 vol%, 3 vol%, 4 vol%, 5 vol%, 6 vol%, 7 vol%, 8 vol%, 9 vol%, and 10 vol%, or a range between any two of them; and the surfactant concentration can be, for example, any one of 1 vol%, 2 vol%, 3 vol%, 4 vol%, and 5 vol%, or a range between any two of them. The acid includes, but is not limited to, any one of hydrochloric acid, sulfuric acid, nitric acid, malic acid, and citric acid, or a combination of more than one of them. The reducing agent includes, but is not limited to, any one of hydrogen peroxide, sodium sulfite, and glucose, or a combination of more than one of them. Surfactants include but are not limited to sodium lauryl sulfate and cetyltrimethylammonium bromide in a mass ratio of 1:(1-3). In some embodiments, the mass ratio of sodium lauryl sulfate and cetyltrimethylammonium bromide can be, for example, any one of 1:1, 1:1.5, 1:2, 1:2.5, 1:3 or a range value between any two of them.

[0048] The mixed liquid and the black powder are mixed at a liquid-to-solid ratio of 40 g / L to 120 g / L for acid leaching. The temperature during the acid leaching is 60° C. to 80° C., and the acid leaching time is 4 h to 8 h. Stirring is continued during the acid leaching process to obtain a leachate, which is then filtered to obtain a purified liquid.

[0049] In some embodiments, the liquid-to-solid ratio of the mixed liquid to the black powder can be, for example, any one of 40 g / L, 60 g / L, 80 g / L, 1000 g / L, 120 g / L, or a range between any two of them, the pickling temperature can be, for example, any one of 60° C., 65° C., 70° C., 75° C., 80° C., or a range between any two of them, and the pickling time can be, for example, any one of 4 h, 5 h, 6 h, 7 h, 8 h, or a range between any two of them.

[0050] S3, spray drying to obtain nickel-cobalt-manganese lithium oxide powder.

[0051] The purified liquid is spray pyrolyzed to obtain nickel-cobalt-manganese lithium oxide powder. During the spray pyrolysis, the purified liquid is dried with hot air at a temperature of 200°C to 800°C. Specifically, the spray pyrolysis includes a first temperature zone, a second temperature zone, and a third temperature zone arranged from top to bottom. The temperature of the first temperature zone is 200°C to 300°C, the temperature of the second temperature zone is 400°C to 500°C; the temperature of the third temperature zone is 600°C to 800°C, and a nozzle for introducing the purified liquid is provided at the top of the first temperature zone. The flow rate of the purified liquid during spray pyrolysis is 4L / h to 12L / h. The flow rate of hot air is 4m 3 / L~8m 3 / L. In the present disclosure, the purified liquid is sprayed from the top and comes into contact with the hot air during the spraying, thereby achieving drying. In the present disclosure, the temperature gradually increases from top to bottom, so that the purified liquid first exchanges heat with the lower hot air, so that the material in the purified liquid does not heat up rapidly and cause unstable components. By gradually increasing the temperature, the drying effect is high and the material composition is stable. At the same time, the present disclosure also limits the flow rate of the purified liquid, which can ensure efficiency while ensuring quality, and obtain nickel-cobalt-manganese lithium oxide powder with better quality. When the flow rate is too large, the nickel-cobalt-manganese lithium oxide powder in the purified liquid cannot be completely dried and precipitated, and the nickel-cobalt-manganese lithium oxide powder will accumulate, resulting in poor dispersion effect. If the flow rate is too small, the hot air utilization efficiency will be poor. Directly spray drying the purified liquid is more efficient, shorter-range, and faster than other methods such as chemical precipitation, biological methods, wet purification methods, and direct drying.

[0052] After spray pyrolysis, the acid gas carried in the hot air is collected and converted into recovered acid, which is then returned to the mixed liquid for reuse. This acid gas recycling prevents direct air pollution from acid gas emissions, maximizes resource utilization, and saves costs.

[0053] S4, supplementing lithium and sintering to obtain regenerated nickel cobalt manganese oxide positive electrode material.

[0054] Lithium carbonate is added to nickel-cobalt-manganese lithium oxide powder in an amount of 4% to 6% by mass of the nickel-cobalt-manganese lithium oxide powder. The powder is then sintered at a temperature of 700°C to 900°C for 10 to 20 hours to obtain a regenerated nickel-cobalt-manganese lithium oxide positive electrode material.

[0055] In the present disclosure, by directly supplementing the nickel-cobalt-manganese lithium oxide powder with lithium, the amount of lithium added is excessive, ensuring that the nickel-cobalt-manganese lithium oxide powder is completely converted into regenerated nickel-cobalt-manganese oxide. Furthermore, during the sintering process, the surfactant remaining on the surface of the nickel-cobalt-manganese lithium oxide powder can refine the grain size of the material's 003 crystal plane, increasing the crystal plane activity and improving the capacity. The sintering temperature can be, for example, any one of 700°C, 750°C, 800°C, 850°C, and 900°C, or a range between any two thereof, and the sintering time can be any one of 10 hours, 12 hours, 15 hours, 18 hours, and 20 hours, or a range between any two thereof.

[0056] The 003 crystal plane grain size of the recycled lithium nickel cobalt manganese oxide positive electrode material is 400 angstroms to 420 angstroms.

[0057] The features and performance of the present disclosure are further described in detail below with reference to the embodiments.

[0058] Example 1

[0059] A short-range regeneration method for waste nickel-cobalt-manganese-oxide lithium cathode material, comprising:

[0060] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0061] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2, and 5 vol% surfactant, and then the solid-liquid ratio was 120 g / L. The mixture was stirred at 80°C for 4 h to obtain a leachate, and the leaching rate was tested by ICP. The surfactant was sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:1.

[0062] (3) The purified liquid was filtered and passed into the spray pyrolysis device at a flow rate of 7 L / h. At the same time, hot air was heated at a flow rate of 8 m 3The purified liquid was spray-pyrolyzed at 400°C and 750°C to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration and element testing, lithium carbonate (5% excess) was added and sintered in an 800°C kiln for 12 hours to obtain a black powder for phase analysis. In addition, the acid carried by the hot gas was collected and reused.

[0063] (4) The material is made into a button-type half-cell to test the electrochemical performance.

[0064] (5) Please refer to Figure 2 As shown in Table 1, Example 1 Figure 2 The calculated grain size is the smallest and the discharge specific capacity is the highest, 219.6 mAh / g.

[0065] Example 2:

[0066] A short-range regeneration method for waste nickel-cobalt-manganese-oxide lithium cathode material, comprising:

[0067] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0068] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2 and 5 vol% surfactant, and then the solid-liquid ratio was 120 g / L. The mixture was stirred at 80°C for 4 h to obtain a leachate, and the leaching rate was tested by ICP. The surfactant was sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:2.

[0069] (3) The purified liquid was filtered and passed into the spray pyrolysis device at a flow rate of 7 L / h. At the same time, hot air was heated at a flow rate of 8 m 3 The purified liquid was spray-pyrolyzed at 400°C and 750°C to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration and element testing, lithium carbonate (5% excess) was added and sintered in an 800°C kiln for 12 hours to obtain a black powder for phase analysis. In addition, the acid carried by the hot gas was collected and reused.

[0070] (4) The material is made into a button-type half-cell to test the electrochemical performance.

[0071] Example 3:

[0072] A short-range regeneration method for waste nickel-cobalt-manganese-oxide lithium cathode material, comprising:

[0073] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0074] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2 and 5 vol% surfactant, and then the solid-liquid ratio was 120 g / L. The mixture was stirred at 80°C for 4 h to obtain a leachate, and the leaching rate was tested by ICP. The surfactant was sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:3.

[0075] (3) The purified liquid was filtered and passed into the spray pyrolysis device at a flow rate of 7 L / h. At the same time, hot air was heated at a flow rate of 8 m 3 The purified liquid was spray-pyrolyzed at 400°C and 750°C to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration and element testing, lithium carbonate (5% excess) was added and sintered in an 800°C kiln for 12 hours to obtain a black powder for phase analysis. In addition, the acid carried by the hot gas was collected and reused.

[0076] (4) The material is made into a button-type half-cell to test the electrochemical performance.

[0077] Example 4:

[0078] A short-range regeneration method for waste nickel-cobalt-manganese-oxide lithium cathode material, comprising:

[0079] (1) Soak the used battery in a 2 mol / L sodium chloride solution for 6 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in an NMP solution heated to 60°C and stir it at 450 rpm for 5 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 650°C for 6 hours to remove PVDF and binder to obtain a black powder.

[0080] The black powder was mixed with 0.5 mol / L sulfuric acid, 3 vol% H2O2 and 3 vol% surfactant, and then the solid-liquid ratio was 40 g / L. The mixture was stirred at 60°C for 6 hours to obtain a leachate, and the leaching rate was tested by ICP. The surfactant was sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:3.

[0081] The purified liquid was filtered and passed into the spray pyrolysis device at a flow rate of 6L / h. At the same time, hot air was 3 / L flow rate, so that the purified liquid in the three temperature zones of 200 ° C, 400 ° C, and 750 ° C after spray pyrolysis to obtain nickel, cobalt and manganese lithium oxide powder. After ICP titration test elements, lithium carbonate (5% excess) was added and sintered in a kiln at 700 ° C for 18 hours to obtain a black powder for phase analysis. In addition, the acid carried by the hot gas was collected and reused.

[0082] The material was made into a button-type half-cell to test its electrochemical performance.

[0083] Example 5:

[0084] A short-range regeneration method for waste nickel-cobalt-manganese-oxide lithium cathode material, comprising:

[0085] (1) Soak the used battery in a 5 mol / L sodium chloride solution for 4 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in an NMP solution heated to 70°C and stir it at 450 rpm for 15 minutes to allow the positive electrode active material to fall off. Rinse with deionized water, dry at 120°C, and then calcine at 750°C for 4 hours to remove PVDF and binder, obtaining a black powder.

[0086] The black powder was mixed with 1 mol / L sulfuric acid, 8 vol% H2O2 and 1 vol% surfactant, and then the solid-liquid ratio was 80 g / L. The mixture was stirred at 70°C for 8 hours to obtain a leachate, and the leaching rate was tested by ICP. The surfactant was sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:3.

[0087] The purified liquid was filtered and passed into the spray pyrolysis device at a flow rate of 8L / h. At the same time, hot air was 3 The purified liquid was spray-pyrolyzed at three temperature zones (300°C, 500°C, and 800°C) to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration and elemental testing, lithium carbonate (5% excess) was added and sintered in a 900°C kiln for 10 hours to obtain a black powder for phase analysis. Furthermore, the acid carried by the hot gas was collected and reused.

[0088] The material was made into a button-type half-cell to test its electrochemical performance.

[0089] Comparative Example 1

[0090] This comparative example is substantially the same as Example 1, except that only one surfactant is used in this comparative example. Specifically, this comparative example comprises the following steps:

[0091] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0092] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2, and 5 vol% surfactant (sodium lauryl sulfate) at a solid-liquid ratio of 120 g / L, set the temperature to 80°C, and stirred for 4 h to obtain a leachate. The leaching rate was tested by ICP.

[0093] (3) The purified liquid was filtered and spray-pyrolyzed at 400°C and 750°C to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration for elemental analysis, lithium carbonate (5% excess) was added and sintered in an 800°C kiln for 12 hours to obtain a black powder for phase analysis. In addition, the acid carried by the hot gas was collected and reused;

[0094] (4) The material is made into a button-type half-cell to test the electrochemical performance.

[0095] Comparative Example 2

[0096] This comparative example is substantially the same as Example 1, except that only one surfactant is used in this comparative example. Specifically, this comparative example comprises the following steps:

[0097] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0098] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2, and 5 vol% surfactant (cetyltrimethylammonium bromide) at a solid-liquid ratio of 120 g / L, set the temperature to 80°C, and stirred for 4 h to obtain a leachate. The leaching rate was tested by ICP.

[0099] (3) The purified liquid was filtered and spray-pyrolyzed at 400°C and 750°C to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration for elemental analysis, lithium carbonate (5% excess) was added and sintered in an 800°C kiln for 12 hours to obtain a black powder for phase analysis. In addition, the acid carried by the hot gas was collected and reused;

[0100] (4) The material is made into a button-type half-cell to test the electrochemical performance.

[0101] Comparative Example 3

[0102] This comparative example is basically the same as Example 1, except that other surfactants are used in this comparative example. Specifically, this comparative example includes the following steps:

[0103] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0104] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2 and 5 vol% other surfactant (sodium dodecylbenzene sulfonate) at a solid-liquid ratio of 120 g / L, the temperature was set to 80°C, and the mixture was stirred for 4 h to obtain a leachate. The leaching rate was tested by ICP, sodium carbonate was added to extract lithium, and the purified liquid and lithium carbonate were obtained by filtration.

[0105] (3) The purified liquid was filtered and spray pyrolyzed at 750°C to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration testing of the elements, lithium carbonate (5% excess) was added and sintered in a kiln at 800°C for 12 hours. The acid carried by the hot gas was collected and reused.

[0106] (4) The material is made into a button-type half-cell to test the electrochemical performance.

[0107] Comparative Example 4

[0108] This comparative example is basically the same as Example 1, except that the surfactant in this comparative example is sodium lauryl sulfate and cetyltrimethylammonium bromide in a mass ratio of 2:1. Specifically, this comparative example includes the following steps:

[0109] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0110] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2, and 5 vol% surfactant, and then the solid-liquid ratio was 120 g / L. The mixture was stirred at 80°C for 4 h to obtain a leachate, and the leaching rate was tested by ICP. The surfactant was sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 2:1.

[0111] (3) The purified liquid was filtered and spray-pyrolyzed at 400°C and 750°C to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration for elemental analysis, lithium carbonate (5% excess) was added and sintered in an 800°C kiln for 12 hours to obtain a black powder for phase analysis. In addition, the acid carried by the hot gas was collected and reused;

[0112] (4) The material is made into a button-type half-cell to test the electrochemical performance.

[0113] Comparative Example 5

[0114] This comparative example is basically the same as Example 1, except that the surfactant in this comparative example is sodium lauryl sulfate and cetyltrimethylammonium bromide in a mass ratio of 1:5. Specifically, this comparative example includes the following steps:

[0115] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0116] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2 and 5 vol% surfactant, and then the solid-liquid ratio was 120 g / L. The mixture was stirred at 80°C for 4 h to obtain a leachate, and the leaching rate was tested by ICP. The surfactant was sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:5.

[0117] (3) The purified liquid was filtered and spray-pyrolyzed at 400°C and 750°C to obtain nickel-cobalt-manganese lithium oxide powder. After ICP titration for elemental analysis, lithium carbonate (5% excess) was added and sintered in an 800°C kiln for 12 hours to obtain a black powder for phase analysis. In addition, the acid carried by the hot gas was collected and reused;

[0118] (4) The material is made into a button-type half-cell to test the electrochemical performance.

[0119] Comparative Example 6

[0120] This comparative example is basically the same as Example 1, except that the purified liquid is not spray-dried in this comparative example, but the nickel-cobalt-manganese-lithium hydroxide precursor is prepared by coprecipitation. Figure 3 , this comparative example comprises the following steps:

[0121] (1) Soak the used battery in 8 mol / L sodium chloride solution for 5 hours and discharge it to below 1V. Then manually disassemble the battery and separate the positive electrode. Place it in NMP solution heated to 75°C and stir it at 450 rpm for 10 minutes to remove the positive electrode active material. Rinse with deionized water, dry at 120°C, and then calcine at 600°C for 4 hours to remove PVDF and binder to obtain black powder.

[0122] (2) The black powder was mixed with 2 mol / L sulfuric acid, 10 vol% H2O2 and 5 vol% surfactant, and then the solid-liquid ratio was 120 g / L. The mixture was stirred at 80°C for 4 h to obtain a leachate, and the leaching rate was tested by ICP. Sodium carbonate was added to extract lithium, and the purified solution and lithium carbonate were obtained by filtration. The surfactant was sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:5.

[0123] (3) Place the purified liquid in a reactor and heat it to 72°C. Stirring is started and maintained at 500 rpm. Slowly add ammonia water to adjust the concentration to 2.5 g / L. Then slowly add NaOH solution. After nucleation and growth for 20 hours, a coprecipitated product is obtained. Wash with 0.8 M sodium hydroxide, rinse with 75°C warm water, and dry at 120°C to obtain nickel-cobalt-manganese hydroxide.

[0124] (4) Nickel-cobalt-manganese hydroxide and lithium carbonate (5% excess) obtained in the second step are placed in a kiln and sintered at 800° C. for 12 h to obtain nickel-cobalt-manganese oxide.

[0125] (5) The material is made into a button-type half-cell to test the electrochemical performance.

[0126] Please refer to Table 1 for the test results of Examples 1-5 and Comparative Examples 1-6.

[0127] Table 1. Statistics of detection results for different examples

[0128]

[0129] As can be seen from the above table, the surfactants obtained by adding sodium dodecyl sulfate and hexadecyltrimethylammonium bromide in different proportions to Examples 1, 2, and 3 significantly improved the leaching rate compared to the single surfactant (Comparative Examples 1-3), and the ratio of sodium dodecyl sulfate to hexadecyltrimethylammonium bromide of 1:2 was the best effect, with the highest leaching rate and the best performance. It can be seen from Comparative Examples 4 and 5 that even if the surfactants used were sodium dodecyl sulfate and hexadecyltrimethylammonium bromide provided by the present disclosure, but their mass ratio was not within the scope of the present application, their effect on reducing the size of the 003 crystal plane grains was significantly worse than that of Example 1. The spray drying method can effectively shorten the preparation time compared to the coprecipitation method of Comparative Example 6. Although the coprecipitation method in Comparative Example 6 can also obtain a good 003 crystal plane grain size, its principle of reducing the 003 crystal plane grain size is completely different from that of the present disclosure, and its preparation time is long. Therefore, it can be seen that by combining sodium dodecyl sulfate and cetyltrimethylammonium bromide in a specific ratio, the 003 crystal plane grain size can be significantly reduced, while single sodium dodecyl sulfate or cetyltrimethylammonium bromide, other ratios of the two, or other surfactants cannot achieve the requirement of reducing the 003 crystal plane grain size.

[0130] In summary, the surfactant formed by adding sodium dodecyl sulfate and hexadecyltrimethylammonium bromide in a specific proportion in the present disclosure greatly improves the leaching rate of the process. The present disclosure is different from the existing conventional solution of adding a surfactant to change the morphology of the prepared precursor and reduce the external particle size of the material itself. The present disclosure does not need to prepare the nickel-cobalt-manganese lithium hydroxide precursor by the conventional co-precipitation method on the purified liquid after leaching, but directly sprays the purified liquid to obtain nickel-cobalt-manganese lithium oxide powder. At the same time, there is no washing process, so that the surfactant remains on the surface of the nickel-cobalt-manganese lithium oxide powder. Subsequently, during the sintering process, the surfactant remaining on the surface of the nickel-cobalt-manganese lithium oxide powder can refine the grain size of the material 003 crystal, increase the crystal surface activity, and improve the capacity.

[0131] The foregoing description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

[0132] Industrial Applicability

[0133] In the present disclosure, a surfactant is added by mixing sodium dodecyl sulfate and hexadecyltrimethylammonium bromide in a specific proportion. The addition of the surfactant greatly improves the leaching rate of the process. In addition, the present disclosure is different from the existing conventional solution of adding a surfactant to change the morphology of the prepared precursor and reduce the external particle size of the material itself. The present disclosure does not need to prepare the nickel-cobalt-manganese lithium hydroxide precursor by the conventional co-precipitation method on the purified liquid after leaching. Instead, the purified liquid is directly spray-pyrolyzed to obtain nickel-cobalt-manganese lithium oxide powder. At the same time, there is no washing process, so that the surfactant remains on the surface of the nickel-cobalt-manganese lithium oxide powder. Subsequently, during the sintering process, the surfactant remaining on the surface of the nickel-cobalt-manganese lithium oxide powder can refine the grain size of the material 003 crystals, increase the crystal surface activity, and improve the capacity.

Claims

1. A short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material, characterized in that: It includes: Separating a positive electrode active material from a waste lithium nickel cobalt manganese oxide battery, and calcining the positive electrode active material to remove PVDF and a binder to obtain a black powder; A mixture of an acid, a reducing agent, and a surfactant is mixed with the black powder for acid leaching to obtain a leachate, which is filtered to obtain a purified liquid; wherein the surfactant is sodium lauryl sulfate and hexadecyltrimethylammonium bromide in a mass ratio of 1:(1-3); The purified liquid is spray-pyrolyzed to obtain nickel-cobalt-manganese lithium oxide powder, and lithium carbonate is added to the nickel-cobalt-manganese lithium oxide powder for sintering to obtain a regenerated nickel-cobalt-manganese lithium oxide positive electrode material.

2. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material according to claim 1, characterized in that: The solid-to-liquid ratio of the black powder to the mixed liquid is 40 g / L to 120 g / L.

3. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material according to claim 1, characterized in that: The concentration of the surfactant in the mixed solution is 1 vol% to 5 vol%.

4. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material according to claim 1, characterized in that: The hydrogen ion concentration of the acid in the mixed solution is 0.5 mol / L to 2 mol / L.

5. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material according to claim 1, characterized in that: The acid includes any one or a combination of multiple of hydrochloric acid, sulfuric acid, nitric acid, malic acid and citric acid.

6. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material according to claim 1, characterized in that: The concentration of the reducing agent in the mixed solution is 1 vol% to 10 vol%.

7. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material according to claim 1, characterized in that: The reducing agent includes any one of hydrogen peroxide, sodium sulfite and glucose, or a combination of multiple thereof.

8. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material according to claim 1, characterized in that: The acid leaching temperature is 60°C to 80°C, and the acid leaching time is 4 h to 8 h.

9. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode material according to claim 1, characterized in that: Stirring is continued during the pickling process.

10. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode materials according to claim 1, characterized in that: During the spray pyrolysis, the purified liquid is dried using hot air at a temperature of 200° C. to 800° C.

11. The short-range regeneration method for waste nickel-cobalt-lithium manganese oxide positive electrode material according to claim 10, characterized in that: The spray pyrolysis includes a first temperature zone, a second temperature zone and a third temperature zone arranged from top to bottom. The temperature of the first temperature zone is 200°C-300°C, the temperature of the second temperature zone is 400°C-500°C; the temperature of the third temperature zone is 600°C-800°C, and a nozzle for introducing the purification liquid is provided at the top of the first temperature zone.

12. The short-range regeneration method for waste nickel-cobalt-lithium manganese oxide positive electrode material according to claim 10, characterized in that: During the spray pyrolysis, the flow rate of the purified liquid is 4 L / h to 12 L / h, and the flow rate of the hot air is 4 m 3 / L~8 m 3 / L.

13. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode materials according to claim 10, characterized in that: The acid gas carried in the hot air after the spray pyrolysis is collected and then acidified to form recovered acid, which is then returned to the mixed liquid for reuse.

14. The short-range regeneration method for waste nickel cobalt lithium manganese oxide positive electrode materials according to claim 1, characterized in that: The amount of lithium carbonate added is 4% to 6% of the mass of the nickel-cobalt-manganese lithium oxide powder.

15. The short-range regeneration method for waste nickel-cobalt-lithium manganese oxide positive electrode material according to claim 1, characterized in that: The sintering temperature is 700°C to 900°C, and the sintering time is 10 h to 20 h.

16. The short-range regeneration method for waste nickel-cobalt-lithium manganese oxide positive electrode material according to claim 1, characterized in that: The method for separating the positive electrode active material comprises: immersing the waste nickel cobalt manganese oxide lithium battery in a salt solution for discharge, disassembling the battery after discharge, separating the positive electrode sheet, placing the positive electrode sheet in an NMP solution heated to 60° C. to 75° C. for 5 min to 15 min to allow the positive electrode active material to fall off, rinsing with deionized water, and drying the battery to obtain the positive electrode active material.

17. The short-range regeneration method for waste nickel-cobalt-lithium manganese oxide positive electrode material according to claim 16, characterized in that: The salt solution is 2 mol / L to 8 mol / L sodium chloride salt solution.

18. The short-range regeneration method for waste nickel-cobalt-lithium manganese oxide positive electrode materials according to claim 16, characterized in that: The soaking time is 4 h to 6 h.

19. The short-range regeneration method for waste nickel-cobalt-lithium manganese oxide positive electrode materials according to claim 1, characterized in that: The calcination includes calcining at 600° C. to 750° C. for 4 h to 6 h.

20. The short-range regeneration method for waste lithium nickel cobalt manganese oxide positive electrode materials according to claim 1, characterized in that: The 003 crystal plane grain size of the regenerated nickel cobalt lithium manganese oxide positive electrode material is 400 angstroms to 420 angstroms.

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