A method for preparing catalyst using waste lithium-ion batteries and its application in hydrogen production
The NiFeCoMnAl alloy catalyst is prepared by a one-step reduction method, which simplifies the recycling process of waste lithium-ion batteries, achieves efficient hydrogen production and lithium element reuse, solves the problems of complex process and high cost in existing technologies, and conforms to the concept of green production.
Patent Information
- Application Number
- CN202410966157.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-18
- Publication Date
- 2025-10-03
- Estimated Expiration
- 2044-07-18
AI Technical Summary
The existing recycling process for waste lithium-ion batteries is complex, and the metal element separation and purification process is tedious, resulting in high costs and high reagent consumption, making it difficult to achieve efficient value-added utilization of lithium-ion battery resources.
A one-step reduction method is used to prepare a NiFeCoMnAl alloy catalyst from lithium-ion battery leachate. The waste lithium-ion battery positive electrode powder is leached using a sulfuric acid and hydrogen peroxide leaching system, combined with sodium borohydride reduction to prepare the catalyst, and the lithium element is recovered by magnetic separation, avoiding complex separation and purification processes.
The recycling process is simplified, the cost is reduced, the catalyst can be efficiently and stably decomposed into chemical hydrogen storage materials to produce hydrogen, the lithium element can be reused, which is in line with the green production concept and increases the added value of waste lithium-ion batteries.
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Figure CN119016061B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of recycling waste lithium-ion batteries, and in particular to a method for preparing a catalyst using waste lithium-ion batteries and an application of the catalyst in hydrogen production. Background Art
[0002] At present, the recycling and utilization of waste lithium-ion batteries mainly adopts pyrometallurgical or hydrometallurgical methods to separate the metal elements individually, that is, to obtain single metal elements such as lithium, cobalt, nickel, manganese, copper, aluminum, and iron, or to separate the groups to obtain a mixture of nickel, cobalt, and manganese to prepare new precursor materials.
[0003] For example, Gao et al. used formic acid as leaching agent and H2O2 as reducing agent to leach LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, first add NaOH to adjust the pH to 6.45 and then add ammonia to precipitate Al 3+ ; Then, the pH was adjusted and vacuum filtered to obtain a mixture of Ni(OH)2, Co(OH)2 and Mn(OH)2; finally, it was adjusted to neutral with formic acid and Na2CO3 was added to obtain Li2CO3 precipitation. After removing Cu from the lithium-ion battery leachate, Li et al. extracted 100% of Fe and 40.3% of Mn to synthesize Fe-doped lithium ion sieve, and co-precipitated Ni, Co and the remaining Mn to prepare Ni x Co y Mn 1-x-y (OH)2 as the precursor of ternary positive electrode material.
[0004] Separating the individual metal elements requires leaching or roasting the cathode powder, followed by precipitation and extraction to separate the elements. This process is lengthy to achieve high metal purity. Preparing battery precursors requires removing substances like iron, copper, and carbon from the solution. The quality requirements for ternary battery precursors require that the iron and copper content be less than 0.03% of the total nickel, cobalt, and manganese, making their removal difficult.
[0005] Therefore, whether it is to separate and obtain a single metal element or to prepare a precursor, there are extremely high requirements for product purity, which makes the recycling process very complicated. Summary of the Invention
[0006] To overcome the problems of the prior art, the present invention aims to provide a method for preparing a catalyst using waste lithium-ion batteries and its application in hydrogen production. This method avoids the separation and purification process of metal elements in the recovery of waste lithium ions and uses a one-step reduction method to prepare a NiFeCoMnAl alloy catalyst from lithium-ion battery leachate. This catalyst can efficiently and stably decompose chemical hydrogen storage materials to produce hydrogen, and also separates lithium, the most expensive element in waste lithium-ion batteries.
[0007] In order to achieve the above object, the technical solution adopted by the present invention is:
[0008] A method for preparing a hydrogen production catalyst using waste lithium-ion batteries comprises the following steps:
[0009] Step 1: Leaching the waste lithium-ion battery positive electrode powder using a sulfuric acid and hydrogen peroxide leaching system at 60° C. to 80° C. to obtain a leachate containing metal ions of lithium, nickel, cobalt, and manganese;
[0010] Step 2: dissolving the leachate, iron salt and surfactant in water, adjusting the pH value, and stirring thoroughly to uniformly mix the substances to obtain a mixed solution;
[0011] Step 3: Sodium borohydride is added to the mixed solution to obtain a black suspension, namely the NiFeCoMnAl catalyst; (through sodium borohydride reduction, Ni, Fe, Co, Mn, and Al are reduced and converted into a NiFeCoMnAl alloy catalyst, while the lithium element is not reduced and remains in the solution).
[0012] Furthermore, in step 1, the process of obtaining the positive electrode powder is as follows:
[0013] Using saturated sodium chloride aqueous solution to soak 811, 523, 333 series ternary waste lithium-ion batteries to discharge them, opening the shell and taking out the positive electrode sheet, and calcining the positive electrode sheet in a muffle furnace at 400-550°C to obtain positive electrode powder;
[0014] Furthermore, any one of the 811, 523, and 333 series of waste ternary lithium-ion battery positive electrode powders is selected for leaching.
[0015] Furthermore, during the leaching process, the liquid-to-solid ratio of the leachate to the positive electrode powder is 50-10 mL / g. In step 2, the specific preparation steps for preparing the NiFeCoMnAl catalyst by the co-reduction method are as follows:
[0016] Take the leachate, ferrous sulfate heptahydrate, and polyvinylpyrrolidone (PVP) and dissolve them in 3-8 mL of solution, adjust the pH to 6-9, stir thoroughly at 5-25°C, and then immediately add excess sodium borohydride to the solution;
[0017] The amount of iron added is 1:5 to 5:1 (molar ratio) of the nickel content;
[0018] During the catalyst preparation process, the concentration of PVP is 10-60 g / L, and the solution is stirred for 10-30 minutes after addition.
[0019] In step 3, sodium borohydride is added to the solution to reduce nickel, iron, and cobalt metal ions to prepare a NiFeCoMnAl alloy catalyst; the amount of sodium borohydride is 7 times the total amount of nickel, iron, cobalt, aluminum, and manganese metal substances.
[0020] The NiFeCoMnAl catalyst is used to produce hydrogen. The NiFeCoMnAl catalyst (black solid powder) is separated by centrifugation, and the remaining lithium-containing solution is evaporated and concentrated, and then sodium carbonate or sodium phosphate is added to precipitate lithium. A chemical hydrogen storage material is added to the catalyst to produce hydrogen.
[0021] Catalyze the decomposition of chemical hydrogen storage materials to produce hydrogen in the presence of 0-3 mol / L sodium hydroxide and 50-80°C;
[0022] Lithium, the most expensive element in batteries, remains in the solution without being reduced. The catalyst is separated from the solution by its magnetic properties, leaving the solution containing lithium. The lithium-containing solution is evaporated and concentrated, and then sodium carbonate or sodium phosphate is added to precipitate the lithium. The lithium is extracted from the solution, realizing the value-added utilization of waste lithium-ion batteries.
[0023] According to the molar ratio of lithium to sodium phosphate or sodium carbonate in the lithium-containing solution being 3:(2-5.5), sodium phosphate or sodium carbonate is added to the lithium-containing solution, and the precipitate is aged at 70-100° C. for 0.5-2 h, and filtered and washed to obtain lithium phosphate or lithium carbonate;
[0024] The obtained catalyst was washed with water and ethanol three times each, and dried under hydrogen and argon atmospheres.
[0025] Furthermore, the chemical hydrogen storage material is any one of sodium borohydride, ammonia borane and hydrazine hydrate.
[0026] Furthermore, the specific steps of decomposing the chemical hydrogen storage material are as follows:
[0027] Furthermore, the concentration of sodium hydroxide in the solution is controlled to be 0 to 3 mol / L to decompose the chemical hydrogen storage material;
[0028] Furthermore, the solution temperature is controlled at 50 to 80°C;
[0029] Furthermore, the molar ratio of the chemical hydrogen storage material to the catalyst is controlled to be 10:1 to 100:1, and the chemical hydrogen storage material is added to perform a decomposition reaction.
[0030] Beneficial effects of the present invention:
[0031] The present invention discloses a method for preparing a hydrogen production catalyst from waste lithium-ion batteries. Compared with existing processes for producing single metals such as lithium, cobalt, nickel, and manganese from waste lithium-ion batteries, or for preparing new ternary precursors, this method is simpler. It bypasses complex separation and purification steps and directly utilizes a one-step reduction method to obtain the catalyst, thereby reducing recycling costs and the use of chemical reagents. The catalyst is used to produce hydrogen, thus aligning with the concept of green production, both in terms of the process itself and the product (i.e., hydrogen).
[0032] Furthermore, a hydrogen production catalyst has been prepared using nickel, cobalt, and manganese, among other metal elements, from used lithium-ion batteries. This catalyst exhibits excellent hydrogen production and reusability, achieving high-value-added utilization of used lithium-ion batteries. Furthermore, lithium, the most expensive element in used lithium-ion batteries, can be separated and reused after the catalyst is prepared. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 Flowchart of the present invention.
[0034] Figure 2 The invention process flow chart.
[0035] Figure 3 The positive electrode powder obtained by lithium battery calcination. (a) is the positive electrode sheet before calcination, (b) is the positive electrode sheet after calcination, (c) is the aluminum foil after peeling, and (d) is the positive electrode powder.
[0036] Figure 4 The leachate obtained by leaching.
[0037] Figure 5 This is the actual leaching rate result of lithium battery during the leaching process.
[0038] Figure 6 This is a physical picture of catalyst preparation.
[0039] Figure 7 The SEM image of the catalyst and the EDS element distribution map of each element.
[0040] Figure 8 This is the catalyst reduction rate diagram.
[0041] Figure 9 This is a diagram of the catalytic effect of the catalyst. DETAILED DESCRIPTION
[0042] The present invention will be described in further detail below with reference to the accompanying drawings.
[0043] See also Figure 1The present invention discloses a method for preparing a hydrogen production catalyst using waste lithium-ion batteries, comprising the following steps:
[0044] S1. Leach the cathode powder of the ternary waste lithium-ion battery in a system of sulfuric acid and hydrogen peroxide, stirring at 50-80°C and a liquid-solid ratio of 20-100 g / L for 2 hours to obtain a ternary waste lithium-ion battery leachate. Figure 4 .
[0045] The NCM models of ternary waste lithium-ion batteries are 811, 523 and 333;
[0046] The process of obtaining positive electrode powder is as follows:
[0047] Use saturated sodium chloride aqueous solution to soak 811, 523, and 333 series ternary waste lithium-ion batteries to discharge the batteries, remove the outer shells and take out the positive electrode sheets, and use a muffle furnace to calcine the positive electrode sheets at 400-550℃ to obtain positive electrode powder. Figure 3 (a) is the positive electrode sheet before calcination, (b) is the positive electrode sheet after calcination, (c) is the aluminum foil after peeling, and (d) is the positive electrode powder.
[0048] S2. Take a certain amount of ternary waste ion battery leachate, ferrous sulfate heptahydrate and PVP, adjust the pH value, stir for 10-30 minutes, and quickly add excess sodium borohydride to obtain a black catalyst. Figure 6 .
[0049] S3. Add a certain amount of catalyst to a 0-3 mol / L sodium hydroxide solution, control the temperature to 50-80°C, control the molar ratio of the chemical hydrogen storage material to the catalyst to 10:1-100:1, and add the chemical hydrogen storage material to produce hydrogen.
[0050] The chemical hydrogen storage material is any one of formic acid, sodium borohydride, ammonia borane and hydrazine hydrate.
[0051] See also Figure 1 In another feasible embodiment of the present invention, the following is adaptively modified according to the circumstances. Use sulfuric acid and hydrogen peroxide to leach different types of ternary waste lithium-ion battery positive electrode powder, stir at 50-80°C and 20-100g / L for 2 hours to obtain ternary waste lithium-ion battery leachate. Take a certain amount of ternary waste ion battery leachate, ferrous sulfate heptahydrate and PVP, adjust the pH value and stir for 10-30 minutes, quickly add excess sodium borohydride to obtain a black catalyst. Figure 6. A magnet is used to separate the catalyst and the lithium solution to achieve the preferential recovery of lithium. The obtained catalyst is rinsed three times with water and ethanol respectively, and dried under hydrogen and argon atmospheres. No additional reagents or solutions are required in the experiment, avoiding excessive waste of reagents. A certain amount of catalyst is added to a 0-3 mol / L sodium hydroxide solution, the temperature is controlled to 50-80°C, the molar ratio of the chemical hydrogen storage material and the catalyst is controlled to be 10:1-100:1, and the chemical hydrogen storage material is added for decomposition reaction to produce hydrogen. The nickel, cobalt, manganese and other metal ions in the waste lithium-ion batteries are not subjected to a separation and purification process, but are directly converted into NiFeCoMnAl catalysts by a one-step reduction method for catalytic chemical hydrogen storage materials to produce hydrogen. Compared with conventional recycling methods, the cost of recycling is reduced. More importantly, the process for preparing the catalyst is simple, the amount of reagents consumed is small, and the catalyst can be used to produce hydrogen. Therefore, both the process itself and the product (i.e., hydrogen) are in line with the concept of green development. See Figure 2 is a process flow chart of the present invention, Figure 9 The catalyst prepared by the present invention shows how the hydrogen production rate and hydrogen selectivity change over time when catalyzing hydrazine hydrate to produce hydrogen at different sodium hydroxide concentrations and temperatures. This invention avoids the cumbersome steps and redundant reagents of traditional recovery processes. The catalyst prepared by the present invention, through a one-step co-reduction method, preferentially recovers lithium, achieving stable and efficient decomposition hydrogen production, providing a new approach for the value-added utilization of lithium batteries.
[0052] Example 1:
[0053] The 523 type ternary waste lithium-ion battery was discharged, the outer shell was removed and the positive electrode sheet was taken out. The positive electrode sheet was calcined at 500 ° C in a muffle furnace to obtain positive electrode powder.
[0054] Use 4 mol / L sulfuric acid and 6% hydrogen peroxide at 80°C and 50 g / L to leach the cathode powder of waste lithium-ion batteries, stirring for 2 hours to obtain the ternary waste lithium-ion battery leachate. Figure 5 The elements Li, Ni and Co in the leaching solution were analyzed by ICP-OES, and the leaching rates of various elements were calculated to be higher than 95%.
[0055] Take 2 mL of ternary waste battery leachate, add 0.3 g of PVP, and add ferrous sulfate in a nickel-iron ratio of 1:1. Adjust the pH to 8 with sodium hydroxide solution. Then, dilute the solution to 15 mL and stir for 30 minutes. Rapidly add an excess of sodium borohydride to obtain a black catalyst. Use a magnet to separate the catalyst and lithium solution to preferentially recover lithium. Add 1 mol / L sodium hydroxide solution to the catalyst, control the temperature to 60°C, and maintain a molar ratio of ammonia borane to catalyst of 20:1. Ammonia borane is then added to initiate a decomposition reaction. The hydrogen selectivity is 83%.
[0056] Example 2:
[0057] The 811 type ternary waste lithium-ion battery was discharged, the outer shell was removed and the positive electrode sheet was taken out. The positive electrode sheet was calcined at 500 ° C in a muffle furnace to obtain positive electrode powder;
[0058] 3 mol / L sulfuric acid and 6% hydrogen peroxide were used to leach the cathode powder from used lithium-ion batteries at 80°C and 40 g / L of water. After stirring for two hours, a ternary used lithium-ion battery leachate was obtained. ICP-OES analysis of elements such as Li, Ni, and Co in the leachate revealed leaching rates exceeding 90%.
[0059] Take 2mL of ternary waste ion battery leachate, 0.3g PVP, add ferrous sulfate in a nickel-iron ratio of 1:1, adjust the pH to 9 with sodium hydroxide solution, and then dilute the solution to 15mL. Quickly add excess sodium borohydride to obtain a black catalyst with a reduction rate of nickel, cobalt, manganese, and aluminum greater than 97% (see Figure 8 ). A magnet is used to separate the catalyst and lithium solution to achieve preferential recovery of lithium.
[0060] 0.2g of the catalyst was added to a 0.5mol / L sodium hydroxide solution. The temperature was controlled at 60°C, and the molar ratio of hydrazine hydrate to catalyst was controlled at 10:1. Hydrazine hydrate was then added to conduct a decomposition reaction. The hydrogen selectivity was 85%.
[0061] See also Figure 8 The catalytic effect diagram of the present invention is that the present invention realizes the green and high value-added utilization of waste lithium ions through a simple metallurgical process. The present invention adopts a process of leaching first and then co-reduction to convert the Ni in the leachate of high-nickel waste lithium ion batteries into 2+ 、Co 2+ 、Mn 2+ The metal ions are reduced to catalysts for catalytic hydrogen production by chemical hydrogen storage materials, while the unreduced Li + After separation, the waste lithium ions are used to prepare new lithium-ion batteries. This method significantly shortens the recycling process for waste lithium ions and achieves high-value-added utilization of various metal ions. Furthermore, the catalyst prepared by this method outperforms other non-precious metal nickel-based catalysts in catalyzing hydrogen production from chemical materials.
[0062] Figure 7 The SEM and EDS element distribution diagrams of the catalyst are shown in FIG. x Fe y The morphology of CoMnAl catalyst is as follows Figure 7As shown in the figure, it can be seen that the particle size of the catalyst is small, at the nanometer level, and the distribution of each element in the catalyst is uniform, indicating that the prepared catalyst is an alloy of Ni, Fe, Co, Mn, and Al.
[0063] The synthesized catalyst changes over time in hydrogen production from hydrazine at different sodium hydroxide concentrations and temperatures. Overall, increasing the sodium hydroxide concentration improves hydrogen selectivity (i.e., the molar ratio of hydrogen in the catalytic product to the molar ratio of hydrogen in hydrazine) but has little effect on the hydrogen production rate. Increasing the temperature, however, significantly improves both the hydrogen production rate and selectivity.
[0064] The above content is only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.
Claims
1. A method for preparing a hydrogen production catalyst using waste lithium-ion batteries, characterized in that: The following steps are included: Step 1: Leaching the waste lithium-ion battery positive electrode powder using a sulfuric acid and hydrogen peroxide leaching system at 60°C to 80°C to obtain a leachate containing metal ions of lithium, nickel, cobalt, manganese, and aluminum; Step 2: dissolving the leachate, ferrous sulfate heptahydrate, and polyvinylpyrrolidone (PVP) in 3-8 mL of water, adjusting the pH to 6-9, and stirring thoroughly at 5-25° C. to uniformly mix the substances to obtain a mixed solution; the concentration of PVP is 10-60 g / L; and the stirring time is 10-30 min. Step 3: Immediately add an excess of sodium borohydride to the mixed solution to obtain a black suspension, and centrifuge to obtain a NiFeCoMnAl catalyst; The molar ratio of the added amount of iron element to the nickel element content is 1:5~5:
1.
2. The method for preparing a hydrogen production catalyst using waste lithium-ion batteries according to claim 1, characterized in that: In step 1, the process of obtaining the positive electrode powder is as follows: Using saturated sodium chloride aqueous solution to soak 811, 523, 333 series ternary waste lithium-ion batteries to discharge them, opening the shell and taking out the positive electrode sheet, and calcining the positive electrode sheet in a muffle furnace at 400-550℃ to obtain positive electrode powder; Any one of the 811, 523, and 333 series of waste ternary lithium-ion battery positive electrode powders is selected for leaching.
3. The method for preparing a hydrogen production catalyst using waste lithium-ion batteries according to claim 2, characterized in that: During the leaching process, the liquid-to-solid ratio of the leaching solution to the positive electrode powder is 10-50 mL / g.
4. The method for preparing a hydrogen production catalyst using waste lithium-ion batteries according to claim 1, characterized in that: In step 3, sodium borohydride is added to the solution to reduce nickel, iron, cobalt, aluminum, and manganese metal ions to prepare a NiFeCoMnAl catalyst; the amount of sodium borohydride is 7 times the total amount of nickel, iron, cobalt, aluminum, and manganese metal substances.
5. The method for preparing a hydrogen production catalyst using waste lithium-ion batteries according to claim 1, characterized in that: The NiFeCoMnAl catalyst and the lithium-containing solution are separated by centrifugation, and the lithium-containing solution is evaporated and concentrated, and then sodium carbonate or sodium phosphate is added to precipitate lithium; According to the molar ratio of lithium to sodium phosphate or sodium carbonate in the lithium-containing solution being 3:(2-5.5), sodium phosphate or sodium carbonate is added to the lithium-containing solution, the precipitate is aged at 70-100°C for 0.5-2 h, and the lithium phosphate or lithium carbonate is obtained by filtering and washing. The obtained catalyst was washed with water and ethanol three times each, and dried under hydrogen and argon atmospheres.
6. Use of the hydrogen production catalyst prepared by the method according to any one of claims 1 to 5 in hydrogen production, characterized in that: A chemical hydrogen storage material is added to the catalyst to produce hydrogen; the chemical hydrogen storage material is catalyzed to decompose and produce hydrogen under the conditions of 0-3 mol / L sodium hydroxide and 50-80°C, and the amount of sodium hydroxide added is not zero.
7. The use according to claim 6, characterized in that The chemical hydrogen storage material is any one of sodium borohydride, ammonia borane and hydrazine hydrate.
8. The use according to claim 6, characterized in that The molar ratio of the chemical hydrogen storage material and the catalyst is controlled to be 10:1~100:1.