Method for preparing composite sulfur-based catalyst from waste nickel-cobalt-manganese ternary material and application thereof

Abstract

The application discloses a method for preparing a composite sulfur-based catalyst from waste nickel-cobalt-manganese ternary material and application thereof, and belongs to the field of lithium-oxygen battery catalysts. The method comprises the following steps: (1) dispersing waste ternary positive electrode powder in an aqueous solution of an organic acid to obtain a dispersion liquid, heating, adding an aqueous hydrogen peroxide solution, stirring, and performing suction filtration to obtain a leaching solution; (2) mixing thiourea, a surfactant and the leaching solution to obtain a reaction liquid; and (3) placing the reaction liquid and carbon cloth in a sealed container, reacting, cleaning, and drying to obtain a composite sulfur-based catalyst. The composite sulfide of the three transition metals (Ni, Co and Mn) recovered by the method has a catalytic effect on the charging process of a lithium-oxygen battery, and can greatly improve energy efficiency.

Description

TECHNICAL FIELD

[0001] The application relates to a method for preparing a composite sulfur-based catalyst from waste nickel-cobalt-manganese ternary material and application thereof, and belongs to the field of lithium-oxygen battery catalysts. BACKGROUND

[0002] With the surge of retired batteries of new energy vehicles, how to reasonably recycle and secondarily process and utilize the electrode materials of waste lithium ion batteries has become a key problem to be solved in the new energy industry. In ternary cathode materials (NCM811, NCM532, etc.) of lithium ion batteries, the recovery value of Li, Ni, Co and Mn elements is the highest, and the current mainstream mode is to recover lithium sources (lithium carbonate), transition metal sources (nickel sulfate, cobalt sulfate, manganese sulfate, etc.) or to repair and regenerate corresponding cathode materials. Although it has great recovery significance, the process is complicated and the cost is high. Therefore, designing a simple and efficient recycling mode to regenerate waste ternary cathode materials into other electrode materials or electrode catalysts is another efficient and feasible way.

[0003] Aprotic solvent lithium-oxygen batteries have attracted widespread attention due to their ultra-high theoretical energy density (3500 Wh / kg) which is 5-10 times higher than that of commercial lithium ion batteries. The electrochemical reaction equation of lithium-oxygen battery is:

[0004]

[0005] However, due to the slow kinetics of the charging process (decomposition of Li2O2: Li2O2→2Li + +2e - +O2), the charging overpotential increases, which further reduces the energy efficiency of the battery and increases the side reactions, seriously affecting the commercialization process of lithium-oxygen batteries. Studies have shown that transition metal sulfides such as Ni, Co, and Mn can be used as metal-oxygen battery cathode catalysts to reduce the charging overpotential and improve the energy efficiency of the battery. For example, Co9S8 (Adv. Energy Mater. 2018, 8, 1800089), NiS (Adv. Mater. 2022, 34, 2110172), and MnS (J. Energy Chemistry, 2024, 93, 443-452) have been reported. SUMMARY

[0006] According to one aspect of the application, a method for preparing a composite sulfur-based catalyst from waste nickel-cobalt-manganese ternary material is provided. The composite sulfide of the three transition metals (Ni, Co, and Mn) recovered by the method has a catalytic effect on the charging process of lithium-oxygen batteries and can greatly improve the energy efficiency.

[0007] The method for preparing a composite sulfur-based catalyst from waste nickel-cobalt-manganese ternary material described in the present application comprises the following steps:

[0008] (1) dispersing the waste ternary positive electrode powder in an aqueous solution of an organic acid to obtain a dispersion liquid, heating, adding an aqueous hydrogen peroxide solution, stirring, and filtering to obtain a leaching solution;

[0009] (2) mixing thiourea, a surfactant, and the leaching solution to obtain a reaction liquid;

[0010] (3) placing the reaction liquid and carbon cloth in a sealed container, reacting, washing, and drying to obtain a composite sulfur-based catalyst;

[0011] The waste ternary positive electrode powder is LiNi x Co y Mn 1-x-y O2 material, wherein 0 < x ≤ 1, 0 < y ≤ 1, and x + y < 1.

[0012] Optionally, 0.4 < x < 0.6 and 0.1 < y < 0.3.

[0013] Optionally, in step (1), the concentration of the waste ternary positive electrode powder in the dispersion liquid is 15-25 g / L; preferably, the concentration of the waste ternary positive electrode powder in the dispersion liquid is 18-22 g / L.

[0014] Optionally, the organic acid is selected from any one or more of citric acid, malic acid, and oxalic acid.

[0015] Optionally, the concentration of the organic acid in the aqueous solution of the organic acid is 0.4-0.6 M.

[0016] Optionally, in step (1), the heating temperature is 80-95°C.

[0017] Optionally, in step (1), the amount of the aqueous hydrogen peroxide solution added is 1-3% of the volume of the dispersion liquid.

[0018] Optionally, in step (1), the stirring time is 0.5-2 h.

[0019] Optionally, in step (2), the molar ratio of thiourea to the total amount of Ni, Co, and Mn ions in the leaching solution is 1:1-1.5:1.

[0020] Optionally, the surfactant is selected from any one or more of sodium dodecyl benzene sulfonate (SDBS), stearic acid, and sodium dodecyl sulfate (SDS).

[0021] Preferably, the surfactant is SDBS.

[0022] Optionally, the concentration of the surfactant is 0.01-1M; preferably, the concentration of the surfactant is 0.03-0.06M.

[0023] Specifically, the concentration of the surfactant is 0.05M.

[0024] Optionally, in step (2), after mixing, ultrasound is performed;

[0025] The duration of the ultrasound is 1-10 minutes.

[0026] Optionally, in step (3), the reaction temperature is 150-200℃; preferably, the reaction temperature is 170-190℃.

[0027] Specifically, in step (3), the reaction temperature is 180°C.

[0028] Optionally, in step (3), the reaction time is 5-10 hours.

[0029] Optionally, in step (3), the heating rate is 5-15℃ / min.

[0030] This application focuses on the recycling and reuse of transition metals Ni, Co, and Mn. Li does not react during the hydrothermal reaction process and does not produce any byproducts. Li can be recycled by further processing the filtrate after filtration in step (3), which is not a key technology of this application and will not be described in detail here.

[0031] The beneficial effects that this application can produce include:

[0032] 1) This application provides a new approach to recycling and reuse, which obtains a recovery liquid rich in Ni, Co and Mn transition metal elements through a simple recycling method, and further uses a simple hydrothermal method to synthesize a composite sulfur-based transition metal catalyst that has a catalytic effect on the charging process of lithium oxygen batteries, thereby realizing the rational utilization of waste ternary materials.

[0033] 2) This application realizes the preparation of Ni, Co, and Mn transition metal ions recovered from waste lithium battery ternary cathode materials into cathode catalysts with catalytic effect on lithium-oxygen batteries using low cost and simple process, thereby improving the electrochemical performance of lithium-oxygen batteries and realizing resource recycling.

[0034] 3) The method for preparing lithium-oxygen battery cathode catalyst from waste nickel-cobalt-manganese ternary materials provided in this application has a catalytic effect on the charging process of lithium-oxygen batteries by recovering the composite sulfides of the three transition metals (Ni, Co, Mn), which can significantly improve energy efficiency.

[0035] 4) The method provided by the application recovers the regenerated lithium-oxygen battery positive electrode catalyst, has the characteristics of simple preparation method, strong implementability, and high catalytic performance.

[0036] 4) The recycling method disclosed by the application does not use strong acid and strong base, does not produce acid mist, is green and environmentally friendly, and has the advantages of simple recycling process and easy mass production.

[0037] 5) The regeneration method disclosed by the application is a one-step hydrothermal reaction, and has the advantages of simple process and easy preparation. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A flowchart of the method for preparing a lithium-oxygen battery positive electrode catalyst from waste nickel-cobalt-manganese ternary material.

[0039] Figure 2 A physical diagram of the carbon cloth and the inner liner of the reaction kettle.

[0040] Figure 3 An electron microscope photo of the sample of the comparative example (carbon cloth), with a size of 5 μm.

[0041] Figure 4 An electron microscope photo of the sample of Example 1, with a size of 5 μm.

[0042] Figure 5 An electron microscope photo of the sample of Example 2, with a size of 5 μm.

[0043] Figure 6 An XRD spectrum of the samples of the comparative example, Example 1 and Example 2.

[0044] Figure 7 A charge-discharge curve and a comparison of charge platforms of a lithium-oxygen battery using the samples of the comparative example, Example 1 and Example 2. DETAILED DESCRIPTION

[0045] The application will be described in detail below in conjunction with examples, but the application is not limited to these examples.

[0046] The experimental methods not specified in the following examples are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturers.

[0047] Unless otherwise specified, the raw materials and reagents used in the application are purchased through commercial channels and directly used without treatment.

[0048] As Figure 1 , the method for preparing a composite sulfur-based catalyst from waste nickel-cobalt-manganese ternary material includes the following steps:

[0049] (1) Take the waste ternary positive electrode powder, disperse it in an organic acid solution; heat the dispersion liquid to a certain temperature, drop the hydrogen peroxide aqueous solution; after fully stirring to leach the metal ions, perform suction filtration to obtain a leaching liquid rich in Ni, Co and Mn ions.

[0050] (2) Dissolve a certain amount of thiourea in the leaching liquid; drop a small amount of surfactant solution under stirring and ultrasonic.

[0051] (3) Transfer the above solution to the inner container of a high-pressure reaction kettle, place carbon at the bottom of the solution, and after tightening, place it in a high-temperature oven for in-situ hydrothermal reaction; after the reaction is completed, take out the carbon cloth, wash it with deionized water and ethanol, and after vacuum drying, obtain a composite sulfur-based catalyst.

[0052] The waste lithium nickel cobalt manganese oxide powder used in the embodiments of the present application is LiNi 0.5 Co 0.2 Mn 0.3 O2.

[0053] The instruments and methods used in the embodiments of the present application are as follows:

[0054] The scanning electron microscope photos are taken using a field emission scanning electron microscope (Apreo S LoVac of Thermo Fisher Scientific Czech Republic); the XRD curve is measured by a desktop X-ray diffractometer, the model of which is Miniflex 600 of Rigaku Corporation; the charge-discharge curve of the lithium-oxygen battery is obtained by testing on a new Wei BTS test rack produced by Shenzhen Songhe Industry Co., Ltd., the range of the test channel is 5V 5mA, and the minimum current detection lower limit is 0.01mA.

[0055] Example 1:

[0056] (1) Take 2g of waste LiNi 0.5 Co 0.2 Mn 0.3 O2 powder, disperse it in 100ml of citric acid (0.5M) solution, and heat to 90℃.

[0057] (2) Under stirring, drop 2ml of hydrogen peroxide solution into the above dispersion liquid, and continue stirring for 1h; after fully leaching the Ni, Co and Mn transition metal ions, perform suction filtration to obtain the target leaching liquid. The concentrations of Ni, Co and Mn ions in the leaching liquid measured by ICP-OES are 0.119M, 0.048M and 0.071M respectively.

[0058] (3) Dissolve 0.19g of thiourea in 10ml of leaching liquid, add 0.2ml of 0.05M SDBS solution, stir for 5mins and ultrasonic for 5mins.

[0059] (4) The above solution was transferred to the 20 ml high-pressure reactor inner container, and a 10 mm diameter circular carbon cloth was placed at the bottom of the liquid. After tightening, it was placed in a high-temperature oven for in-situ hydrothermal reaction. The reactor was heated from room temperature to 160°C at a rate of 10°C / min, and kept at 160°C for 6h. After the reaction was completed, the carbon cloth was taken out, washed with deionized water and ethanol, and vacuum dried at 60°C to obtain the carbon cloth composite sulfur-based catalyst 1.

[0060] Example 2:

[0061] (1) 2g of waste LiNi 0.5 Co 0.2 Mn 0.3 O2 powder was weighed and dispersed in 100 ml of citric acid (0.5M) solution and heated to 90°C.

[0062] (2) Under stirring, 2ml of hydrogen peroxide solution was added to the above dispersion, and stirring was continued for 1h. After the Ni, Co, Mn transition metal ions were fully leached, the target leaching solution was obtained. The leaching solution was measured by ICP-OES, and the concentrations of Ni, Co and Mn ions were 0.119M, 0.048M and 0.071M, respectively.

[0063] (3) 0.19g of thiourea was dissolved in 10ml of leaching solution, 0.2ml of 0.05M SDBS solution was added, stirred for 5mins and ultrasonicated for 5mins.

[0064] (4) The above solution was transferred to the 20 ml high-pressure reactor inner container, and a 10 mm diameter circular carbon cloth was placed at the bottom of the liquid. After tightening, it was placed in a high-temperature oven for in-situ hydrothermal reaction. The reactor was heated from room temperature to 180°C at a rate of 10°C / min, and kept at 180°C for 8h. After the reaction was completed, the carbon cloth was taken out, washed with deionized water and ethanol, and vacuum dried at 60°C to obtain the carbon cloth composite sulfur-based catalyst 2.

[0065] To explore the catalytic effect of the above two kinds of composite sulfur-based catalysts, 10mm carbon cloth was used as a comparative example for performance comparison.

[0066] A lithium-oxygen battery was assembled with 10mm carbon cloth or composite sulfur-based catalyst as the oxygen electrode, lithium metal as the negative electrode, DMSO solution containing 0.5M LiTFSI as the electrolyte, and glass fiber as the separator, and was placed in a self-made oxygen glove box for electrochemical test. The current density was 0.1mA / cm 2 , and the charge and discharge capacity was controlled at 1mAh / cm 2 for testing.

[0067] Figure 2Optical photographs of the carbon cloth used and the reactor liner are shown. Figure 3 , Figure 4 and Figure 5 Scanning electron microscope images of the comparative example, Example 1, and Example 2 are shown respectively. The comparative example (carbon cloth) is composed of carbon fibers with a diameter of about 10 μm. In Example 1, hydrangea-like products can be observed growing on the carbon fibers. In Example 2, the synthesis temperature and time were changed compared to Example 1, and hydrangea-like products with more regular morphology and looser structure and larger size with a diameter of 2-5 μm can be observed growing on the carbon fibers.

[0068] Figure 6 The XRD patterns of the comparative example, Example 1, and Example 2 samples are shown in comparison. Compared with the comparative example, the samples of Example 1 and Example 2 showed new diffraction peaks at diffraction angles of 2θ = 31.8°, 46.3°, and 54.7°, suggesting that the hydrangea-like product may be a composite product of Co3S4, NiS2, and MnS.

[0069] Figure 7 It shows that at 0.1 mA / cm 2 The battery charge-discharge curves at current density are shown, where the black solid line represents the comparative example, the gray solid line represents Example 1, and the dashed line represents Example 2. Figure 7 It can be seen that after the growth of the sulfide catalyst, the median charging voltage of the lithium-oxygen battery using the samples of Comparative Example 1 and Comparative Example 2 decreased by 35mV and 63mV, respectively, and the energy efficiency increased from 69.3% to 74.9% and 77.7%, respectively. This indicates that the recycled sulfide catalyst in this application can effectively catalyze the charging process of lithium-oxygen batteries, reduce the charging overpotential and improve the energy efficiency.

[0070] This application achieves the low-cost and simple process of preparing Ni, Co, and Mn transition metal ions recovered from waste lithium-ion battery ternary cathode materials into cathode catalysts that have a catalytic effect on lithium-oxygen batteries, thereby improving the electrochemical performance of lithium-oxygen batteries and realizing resource recycling.

[0071] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A method for preparing a composite sulfur-based catalyst from spent nickel-cobalt-manganese ternary material, characterized in that, The method comprises the following steps: (1) dispersing waste ternary positive electrode powder in an aqueous solution of organic acid to obtain a dispersion, heating, adding an aqueous hydrogen peroxide solution, stirring, and filtering to obtain a leaching solution; (2) mixing thiourea, a surfactant, and the leaching solution to obtain a reaction solution; (3) placing the reaction solution and carbon cloth in a sealed container and reacting at 150-200℃ for 5-10h, washing, and drying to obtain a composite sulfur-based catalyst; The waste and old ternary positive electrode powder is LiNi x Co y Mn 1-x-y O2 material, wherein 0 < x < 1, 0 < y < 1, and x + y < 1. The organic acid is selected from any one or more of citric acid, malic acid, and oxalic acid; The concentration of the organic acid in the aqueous solution of the organic acid is 0.4-0.6M; The amount of the aqueous hydrogen peroxide solution added is 1-3% of the volume of the dispersion; The surfactant is selected from any one or more of sodium dodecyl benzene sulfonate, stearic acid, and sodium dodecyl sulfate; The concentration of the surfactant is 0.01-1M; In step (2), the molar ratio of thiourea to the total amount of Ni, Co, and Mn ions in the leaching solution is 1:1-1.5:1; In step (2), the amount of the surfactant added is 1-5% of the volume of the leaching solution.

2. The method of claim 1, wherein the spent nickel-cobalt-manganese ternary material is prepared into a composite sulfur-based catalyst. In step (3), the reaction temperature is 170-190℃.

3. The method for preparing a composite sulfur-based catalyst from spent nickel-cobalt-manganese ternary material according to claim 1, characterized in that, In step (3), the heating rate is 5-15℃ / min.

4. The method of claim 1, wherein the spent nickel-cobalt-manganese ternary material is prepared into a composite sulfur-based catalyst. In step (1), the heating temperature is 80-95℃; In step (1), the stirring time is 0.5-2h.

5. The method of claim 1, wherein the spent nickel-cobalt-manganese ternary material is prepared into a composite sulfur-based catalyst. In step (1), the concentration of the waste ternary positive electrode powder in the dispersion is 15-25g / L.

6. The application of a composite sulfur-based catalyst prepared by the method of claim 1 in a lithium-oxygen battery positive electrode catalyst.

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