Industrial waste residue high-entropy doped positive electrode material, preparation method and application thereof

Abstract

This invention discloses a high-entropy doped cathode material made from industrial waste, its preparation method, and its application, belonging to the technical field of lithium-ion battery cathode materials. The preparation method of the high-entropy doped cathode material made from industrial waste includes the following steps: mixing industrial waste, a ternary cathode material precursor, and a lithium source, followed by two-stage calcination to obtain the high-entropy doped cathode material; when the mass fraction of silicon in the industrial waste is ≥10%, the method further includes pretreatment of the industrial waste; the pretreatment includes alkaline calcination of the industrial waste. This invention, by adjusting the mass fraction of silicon in the industrial waste and using it as a dopant in lithium-ion battery cathode materials, provides a new approach to the recycling of industrial waste and the improvement of the cycle stability of cathode materials, and can significantly improve the cycle stability of cathode materials.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery cathode material technology, and more specifically relates to a high-entropy doped cathode material of industrial waste residue, its preparation method and application. Background Technology

[0002] High-nickel ternary cathode materials have gradually become the primary cathode material in the field of new energy electric vehicle power batteries due to their high energy density and low cost. However, with the increase of nickel content, while the discharge capacity of high-nickel cathode materials increases, their cycle performance and stability also deteriorate. Therefore, it is necessary to further optimize the microstructure, composition distribution, and surface stability of high-nickel cathode materials to improve the energy density of lithium-ion batteries. Among these methods, elemental doping has become a research hotspot for improving battery stability due to its simplicity, efficiency, and lack of additional operational steps and equipment. Currently, commonly used dopants for lithium-ion battery cathode materials include silicon, lithium cobalt oxide, fluorides, sulfides, and selenides. While these dopants can improve the cycle stability of lithium-ion batteries, they suffer from drawbacks such as high cost and difficulty in obtaining them. Therefore, developing low-cost, readily available, and easily processed dopants for lithium-ion battery cathode materials is of great significance. Summary of the Invention

[0003] The purpose of this invention is to provide a high-entropy doped cathode material of industrial waste residue, its preparation method and application. By high-entropy doping of several trace elements in industrial waste residue, the cathode material has good electrochemical performance and cycle stability, thereby solving the problems existing in the prior art. It significantly reduces the cost of dopants used in lithium-ion battery cathode materials while improving the cycle stability of lithium-ion batteries.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] One of the technical solutions of this invention is to provide a method for preparing a high-entropy doped cathode material from industrial waste, comprising the following steps:

[0006] Industrial waste residue, ternary cathode material precursor and lithium source are mixed and then calcined in two stages to obtain high-entropy doped cathode material of industrial waste residue.

[0007] When the mass fraction of silicon in the industrial waste residue is ≥10%, the process further includes pretreatment of the industrial waste residue; the pretreatment includes: alkaline roasting of the industrial waste residue.

[0008] This invention adjusts the mass fraction of silicon in industrial waste to reduce its stickiness and avoid degrading electrochemical performance due to excessive silicon doping. Using silicon as a dopant in lithium-ion battery cathode materials can improve the performance of Li-ion batteries. +The diffusion and migration rate of ions significantly prevents the occurrence of undesirable side reactions, reduces the formation of many undesirable byproducts, and significantly improves the electrochemical performance and cycle stability of lithium-ion battery cathode materials. However, when the silicon content in the waste residue is higher than 10%, the waste residue is highly viscous and will agglomerate after sintering, reducing the battery capacity. Therefore, pretreatment is required to reduce the silicon content in the waste residue to below 10%.

[0009] Optionally, the industrial waste residue includes one or more of high-magnesium silicon-nickel slag, steel slag, copper slag, zinc slag, lead slag, and blast furnace slag; the lithium source includes one or more of lithium hydroxide, lithium carbonate, lithium formate, and lithium silicate; and the chemical formula of the ternary cathode material precursor is Ni. x1 Co y1 Mn z1 (OH)2, Ni x2 Mn y2 Al z2 (OH)2 or Ni x3 Co y3 Al z3 (OH)2, wherein the values ​​of x1, x2 and x3 are independent and range from 0.8 to 0.95, x1+y1+z1=1, x2+y2+z2=1, x3+y3+z3=1, and y1, z1, y2, z2, y3 and z3 are all non-zero.

[0010] Preferably, the molar ratio of the ternary cathode material precursor to the lithium source is 1:1.01 to 1.05; and the mass of the industrial waste residue is 0.5% to 3% of the mass of the ternary cathode material precursor.

[0011] Preferably, oxygen is introduced during the two-stage calcination process, and the oxygen flow rate is 60-250 sccm; the parameters of the two-stage calcination are set as follows: the heating rate is 3-5℃ / min independently, the temperature of the first stage calcination is 400-500℃, the holding time of the first stage calcination is 2-5h, the temperature of the second stage calcination is 600-800℃, and the holding time of the second stage calcination is 12-15h.

[0012] Optionally, the reagent used in the alkali roasting includes sodium hydroxide.

[0013] Preferably, the alkali calcination temperature is 200–900°C, and the alkali calcination time is 10–60 min.

[0014] Preferably, the pretreatment further includes sequentially washing and drying the product obtained from alkali roasting.

[0015] Further, the washing includes: dissolving the product obtained from alkali roasting and then sequentially filtering and washing it; the dissolution temperature is 60-80℃, and the dissolution time is 30-40 min; the solid-liquid ratio of the dissolution is 9-11:1; the drying temperature is 100-150℃, and the drying time is 600-650 min.

[0016] Preferably, the amount of reagent used in the alkali roasting is such that the mass fraction of silicon in the pretreated industrial waste residue is <10%; this not only reduces the stickiness of the industrial waste residue, but also ensures that the electrochemical performance of the obtained cathode material will not be reduced due to excessive silicon content during the subsequent doping process.

[0017] The second technical solution of the present invention provides a method for preparing high-entropy doped cathode material of industrial waste residue, which yields the high-entropy doped cathode material of industrial waste residue.

[0018] The third technical solution of the present invention is to provide the application of the high-entropy doped cathode material of industrial waste in the preparation of lithium-ion batteries.

[0019] The fourth technical solution of the present invention provides a lithium-ion battery, wherein the positive electrode material of the lithium-ion battery is the high-entropy doped positive electrode material of the industrial waste residue.

[0020] The present invention discloses the following technical effects:

[0021] 1. This invention provides a novel, zero-cost high-entropy dopant. By simply adjusting the mass fraction of silicon in industrial waste, it can be used as a dopant in lithium-ion battery cathode materials, offering a new approach to the recycling of industrial waste and improving the cycle stability of cathode materials.

[0022] 2. The high-entropy doped cathode material made from industrial waste residue of the present invention, when tested at a voltage range of 2.8–4.5V, exhibits a capacity retention rate of 95.12% after 100 cycles at 1C. The incorporation of industrial waste residue into the cathode material significantly improves its cycle stability. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the preparation process of the high-entropy doped cathode material of industrial waste residue described in this invention;

[0024] Figure 2 The XRD patterns (a) and magnified portion (b) of the (003) plane of the cathode materials obtained in Example 1 and Comparative Example 1 are shown.

[0025] Figure 3 SEM images of the cathode materials obtained in Example 1 and Comparative Example 1 are shown, where a is Example 1 and b is Comparative Example 1.

[0026] Figure 4 The image shows the EDS diagram of the cathode material obtained in Example 1.

[0027] Figure 5 The graph shows the cycling performance of the cathode materials obtained in Example 1 and Comparative Example 1 in the voltage range of 2.8 to 4.3 V and at a 1C rate.

[0028] Figure 6 The XRD patterns (a) and magnified portion (b) of the (003) plane of the cathode materials obtained in Example 2 and Comparative Example 2 are shown.

[0029] Figure 7 The graph shows the cycling performance of the cathode materials obtained in Example 2 and Comparative Example 2 at a voltage range of 2.8 to 4.5 V and a 1C rate.

[0030] Figure 8 The XRD patterns (a) and magnified portion (b) of the (003) plane of the cathode materials obtained in Example 3 and Comparative Example 3 are shown.

[0031] Figure 9 The graph shows the cycling performance of the cathode materials obtained in Example 3 and Comparative Example 3 in the voltage range of 2.8 to 4.3 V and at a 1C rate.

[0032] Figure 10 The XRD patterns (a) and magnified portion (b) of the (003) plane of the cathode materials obtained in Example 1 and Comparative Example 4 are shown.

[0033] Figure 11 The images show SEM images of impurities in the cathode material obtained in Comparative Example 4 at different magnifications.

[0034] Figure 12 The graph shows the cycling performance of the cathode material obtained in Comparative Example 4 at a voltage range of 2.8–4.3 V and a 1C rate.

[0035] Figure 13 The graph shows the cycling performance of the cathode material obtained in Comparative Example 5 at a voltage range of 2.8–4.3 V and a 1C rate. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0039] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0040] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0041] The present invention first describes the raw materials used in the embodiments and comparative examples:

[0042] The high-magnesium silicon-nickel slag was taken from a nickel-iron alloy smelter in Yunnan Province. The elemental composition and content of the high-magnesium silicon-nickel slag are shown in Table 1. The steel slag was taken from a steelmaking plant in Anhui Province. The elemental composition and content of the steel slag are shown in Table 2.

[0043] Table 1. Elemental composition and content of high-magnesium silicon-nickel slag

[0044]

[0045] Table 2. Elemental composition and content of steel slag

[0046] ω(wt%) Mg Al Si Ca Fe O Other impurities steel slag 4.76 5.23 4.5 28 21.3 35 1.21

[0047] Ni 0.83 Co 0.12 Mn 0.05 OH2 and Ni 0.85 Mn 0.09 Al 0.06Unless otherwise specified, OH2 is prepared according to conventional preparation methods in the art, specifically involving sol-gel method and co-precipitation method.

[0048] Example 1

[0049] This embodiment provides a high-magnesium silicon-nickel slag high-entropy-doped Ni 0.83 Co 0.12 Mn 0.05 The preparation steps for the cathode material are as follows:

[0050] (1) High magnesium silicon nickel slag (Si mass fraction of 19.54% > 10%) and sodium hydroxide are mixed and ground at a mass ratio of 2.5:1, then calcined in a muffle furnace at 500℃ for 40 min. After cooling, the solid product is dissolved in ultrapure water at 70℃ at a liquid-solid ratio of 10:1 for 30 min. After filtration and washing with ultrapure water, it is dried at 100℃ for 600 min to reduce the mass fraction of silicon in the high magnesium silicon nickel slag to < 10%.

[0051] (2) Take the high magnesium silicon nickel slag (mass of Ni) obtained in step (1) 0.83 Co 0.12 Mn 0.05 1% of OH2 by mass), LiOH·H2O (LiOH·H2O and Ni 0.83 Co 0.12 Mn 0.05 The molar ratio of OH₂ is 1.05:1) and Ni 0.83 Co 0.12 Mn 0.05 The mixture of OH₂ and oxygen was introduced into a tube furnace for two-stage calcination. The oxygen flow rate was 200 sccm, and the heating rate was 3℃ / min. The first stage calcination temperature was 500℃, and the holding time was 5 h. The second stage calcination temperature was 750℃, and the holding time was 15 h. The final product was high-magnesium silicon-nickel slag with high entropy doped Ni. 0.83 Co 0.12 Mn 0.05 Positive electrode material.

[0052] Example 2

[0053] This embodiment provides a high-magnesium silicon-nickel slag high-entropy-doped Ni 0.85 Mn 0.09 Al 0.06 The preparation steps for the cathode material are as follows:

[0054] (1) High magnesium silicon nickel slag (Si mass fraction of 19.54% > 10%) and sodium hydroxide are mixed and ground at a mass ratio of 2.5:1, then calcined in a muffle furnace at 500℃ for 40 min. After cooling, the solid product is dissolved in ultrapure water at 70℃ at a liquid-solid ratio of 10:1 for 30 min. After filtration and washing with ultrapure water, it is dried at 100℃ for 600 min to reduce the mass fraction of silicon in the high magnesium silicon nickel slag to < 10%.

[0055] (2) Take the high magnesium silicon nickel slag (mass of Ni) obtained in step (1) 0.85 Mn 0.09 Al 0.06 1% of OH2 by mass), LiOH·H2O (LiOH·H2O and Ni 0.85 Mn 0.09 Al 0.06 The molar ratio of OH₂ is 1.03:1) and Ni 0.83 Co 0.12 Mn 0.05 The mixture of OH₂ and oxygen was introduced into a tube furnace for two-stage calcination. The oxygen flow rate was 200 sccm, and the heating rate was 3℃ / min. The first stage calcination temperature was 400℃, and the holding time was 5 h. The second stage calcination temperature was 750℃, and the holding time was 12 h. The final product was high-magnesium silicon-nickel slag with high entropy doped Ni. 0.85 Mn 0.09 Al 0.06 Positive electrode material.

[0056] Example 3

[0057] This embodiment provides a high-entropy Ni-doped steel slag. 0.83 Co 0.12 Mn 0.05 The preparation steps for the cathode material are as follows:

[0058] Steel slag (Si mass fraction 4.5% < 10%) (Ni mass fraction) 0.83 Co 0.12 Mn 0.05 1% of OH2 by mass), LiOH·H2O (LiOH·H2O and Ni 0.83 Co 0.12 Mn 0.05 The molar ratio of OH₂ is 1.05:1) and Ni 0.83 Co 0.12 Mn 0.05 OH2 was mixed and placed in a tube furnace for two-stage calcination under oxygen flow. The oxygen flow rate was 200 sccm, and the heating rate was 3℃ / min. The first stage calcination temperature was 500℃, and the holding time was 5 h. The second stage calcination temperature was 750℃, and the holding time was 15 h. High-entropy Ni-doped steel slag was finally obtained.0.83 Co 0.12 Mn 0.05 Positive electrode material.

[0059] Comparative Example 1

[0060] The difference from Example 1 is that the addition of high-magnesium silicon-nickel slag is omitted, while the rest is the same as in Example 1.

[0061] Figure 2 The XRD patterns of the cathode materials obtained in Example 1 and Comparative Example 1 are shown below. Figure 3 SEM images of the cathode materials obtained in Example 1 and Comparative Example 1 are shown, where a is Example 1 and b is Comparative Example 1. Figure 4 This is the EDS image of the cathode material obtained in Example 1. Figure 2 It can be seen that the diffraction peaks of the high-entropy doped sample shift to lower angles compared to the undoped sample, indicating that bulk doping was successful; from Figure 3 It can be seen that the high-magnesium silicon-nickel slag prepared in Example 1 is highly entropy-doped with Ni. 0.83 Co 0.12 Mn 0.05 The spherical structure of the positive electrode material remained unchanged; Figure 4 It can be seen that the trace elements in the high magnesium silicon nickel slag are uniformly distributed in the particles, indicating that the doping uniformity is high.

[0062] Comparative Example 2

[0063] The difference from Example 2 is that the addition of high-magnesium silicon-nickel slag is omitted, while the rest is the same as Example 2.

[0064] Figure 6 The images show the XRD patterns of the cathode materials obtained in Example 2 and Comparative Example 2. Figure 6 It can be seen that the diffraction peaks of the high-entropy doped sample shift to lower angles compared to the undoped sample, indicating that the bulk doping was successful.

[0065] Comparative Example 3

[0066] The difference from Example 3 is that the addition of steel slag is omitted, otherwise it is the same as Example 3.

[0067] Figure 8 The images show the XRD patterns of the cathode materials obtained in Example 3 and Comparative Example 3. Figure 8 It can be seen that the diffraction peaks of the high-entropy doped sample shift to lower angles compared to the undoped sample, indicating that the bulk doping was successful.

[0068] Comparative Example 4

[0069] The difference from Example 1 is that step (1) is omitted, and the cathode material is prepared directly using high magnesium silicon nickel slag (Si mass fraction is 19.54% > 10%). The rest is the same as in Example 1.

[0070] Figure 10 The XRD patterns (a) and magnified portion (b) of the (003) plane of the cathode materials obtained in Example 1 and Comparative Example 4 are shown. Figure 11 The images show SEM images of impurities in the cathode material obtained in Comparative Example 4 at different magnifications. Figure 10 and Figure 11 It can be seen that the diffraction peaks of the high-entropy doped sample shift to lower angles compared to the undoped sample, indicating successful bulk doping. However, due to... Figure 11 It can be seen that due to the high silicon content in the high magnesium silicon nickel slag and the high viscosity of the industrial waste slag, trace elements were not fully incorporated during the sintering process, resulting in agglomeration.

[0071] Comparative Example 5

[0072] The difference from Example 1 is that step (1) is omitted, and "high magnesium silicon nickel slag" is replaced with an equal amount of "TiO2", a commonly used dopant in the art. Otherwise, it is the same as Example 1.

[0073] Performance testing:

[0074] Lithium-ion batteries were assembled using the positive electrode materials obtained in Examples 1-3 and Comparative Examples 1-5 as positive electrodes, lithium sheets as negative electrodes, and LB002 as electrolyte. The resulting batteries were subjected to cycle performance tests within a voltage range of 2.8-4.3V and at a 1C rate. The results are as follows: Figure 5 , Figure 7 , Figure 9 , Figure 12 , Figure 13 As shown in Table 3.

[0075] Table 3 shows the cycle stability of lithium-ion batteries prepared from the cathode materials obtained in Examples 1-3 and Comparative Examples 1-5.

[0076]

[0077] Figure 5 This is a graph showing the cycle performance of the cathode materials obtained in Example 1 and Comparative Example 1 at a voltage range of 2.8–4.3 V and a 1C rate. Figure 5 As shown in Table 3, the cathode material of Example 1, which is doped with industrial waste, has a capacity retention rate of 95.12% after 100 cycles, which is significantly improved compared to 78.70% of Comparative Example 1, which is not doped with industrial waste.

[0078] Figure 7 This is a graph showing the cycle performance of the cathode materials obtained in Example 2 and Comparative Example 2 at a voltage range of 2.8–4.5 V and a 1C rate. Figure 7As shown in Table 3, the cathode material of Example 2, which is doped with industrial waste, has a capacity retention rate of 86.46% after 100 cycles, which is significantly improved compared to 73.69% of Comparative Example 1, which is not doped with industrial waste.

[0079] Figure 9 The graph shows the cycling performance of the cathode materials obtained in Example 3 and Comparative Example 3 within a voltage range of 2.8–4.3 V at a 1C rate. Figure 9 As shown in Table 3, the cathode material of Example 3, which is doped with industrial waste, has a capacity retention rate of 92.29% after 100 cycles, which is a significant improvement compared to 77.02% of Comparative Example 1, which is not doped with industrial waste.

[0080] Figure 12 This is a graph showing the cycle performance of the cathode material obtained in Comparative Example 4 within a voltage range of 2.8–4.3 V at a 1C rate. Figure 12 As shown in Table 3, the first-cycle discharge capacity of the obtained cathode material is reduced due to the agglomeration phenomenon in Comparative Example 4.

[0081] Figure 13 This is a graph showing the cycle performance of the cathode material obtained in Comparative Example 5 within a voltage range of 2.8–4.3 V at a 1C rate. Figure 13 As shown in Table 3, compared with the cathode material of Comparative Example 5, which is doped with TiO2, a commonly used dopant in the art, the cathode material of Example 1, which is doped with industrial waste residue, has an improved capacity retention rate after 100 cycles. Moreover, the dopant used is a solid waste material, which is lower in cost and easier to obtain.

[0082] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0083] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-entropy doped cathode material from industrial waste, characterized in that, Includes the following steps: Industrial waste residue, ternary cathode material precursor and lithium source are mixed and then calcined in two stages to obtain high-entropy doped cathode material of industrial waste residue. When the mass fraction of silicon in the industrial waste residue is ≥10%, the process further includes pretreatment of the industrial waste residue; the pretreatment includes: alkaline roasting of the industrial waste residue; The industrial waste residue includes one or more of high-magnesium silicon-nickel slag, copper slag, zinc slag, lead slag, steel slag, and blast furnace slag; the lithium source includes one or more of lithium hydroxide, lithium carbonate, lithium formate, and lithium silicate; the chemical formula of the ternary cathode material precursor is Ni x1 Co y1 Mn z1 (OH)2, Ni x2 Mn y2 Al z2 (OH)2 or Ni x3 Co y3 Al z3 (OH)2, where x1, x2 and x3 take values ​​of 0.8~0.95 independently, x1+y1+z1=1, x2+y2+z2=1, x3+y3+z3=1, and y1, z1, y2, z2, y3 and z3 are all not 0; The molar ratio of the ternary cathode material precursor to the lithium source is 1:1.01~1.05; the mass of the industrial waste residue is 0.5~3% of the mass of the ternary cathode material precursor. Oxygen is introduced during the two-stage roasting process, and the oxygen flow rate is 60~250 sccm; the parameters of the two-stage roasting are set as follows: the heating rate is 3~5℃ / min, the temperature of the first stage roasting is 400~500℃, the holding time of the first stage roasting is 2~5h, the temperature of the second stage roasting is 600~800℃, and the holding time of the second stage roasting is 12~15h. The reagent used in the alkali calcination includes sodium hydroxide; the alkali calcination temperature is 200~900℃, and the alkali calcination time is 10~60min.

2. The preparation method according to claim 1, characterized in that, The pretreatment also includes sequentially washing and drying the product obtained from alkali roasting.

3. The preparation method according to claim 2, characterized in that, The amount of reagent used in the alkali roasting is such that the mass fraction of silicon in the pretreated industrial waste residue is less than 10%.

4. The high-entropy doped cathode material of industrial waste obtained by the preparation method of the high-entropy doped cathode material of industrial waste according to any one of claims 1 to 3.

5. The application of the high-entropy doped cathode material of industrial waste as described in claim 4 in the preparation of lithium-ion batteries.

6. A lithium-ion battery, characterized in that, The cathode material of the lithium-ion battery is the high-entropy doped cathode material of industrial waste as described in claim 4.

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