Sodium ion battery negative electrode material based on recovered lead

Abstract

The invention discloses a sodium-ion battery negative electrode material based on lead recovery, and belongs to the technical field of sodium-ion batteries. The preparation method comprises the following steps: fully discharging a waste lead-acid battery, disassembling and recovering to obtain metal lead, and preparing the metal lead into lead powder through a gas atomization method; mixing and ball-milling the prepared lead powder, metal M and a carbon material to obtain a composite material; wherein the metal M is one or more of Bi, Sn, Sb, Ni, Co, Cu and Fe; mixing the prepared composite material with a battery negative electrode material auxiliary agent to prepare slurry; and coating an aluminum foil with the prepared slurry, and drying. The invention provides a recycled lead-based composite negative electrode active material meeting the application requirement of a sodium-ion battery, and aims to solve the problem of application of a lead-based negative electrode material in the sodium-ion battery and improve the adaptability of the material in the sodium-ion battery.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium ion batteries, in particular to a negative electrode material for a sodium ion battery. Background Art

[0002] Sodium-ion batteries, with their numerous advantages, are gradually emerging as a promising energy storage technology for large-scale applications and smart grids. They are considered a promising new star in next-generation energy storage systems. They offer low cost, abundant sodium resources, and electrochemical properties similar to those of lithium-ion batteries. However, their development faces a number of challenges.

[0003] Sodium ions (Na⁺, 102 picometers in diameter) have a larger ionic radius than lithium ions (Li⁺, 76 picometers in diameter). This property results in sluggish sodium ion insertion kinetics within batteries, making the search for suitable anode materials more challenging.

[0004] Among common anode materials, graphite is the mainstream choice for lithium-ion batteries, but it is not very suitable for sodium-ion batteries. This is because the interlayer spacing of graphite is small and the sodium intercalation compound is not stable enough to meet the working requirements of sodium-ion batteries. Another common carbonaceous material, hard carbon, although capable of storing sodium ions, has many defects. For example, its structural continuity is poor, the specific capacity is limited, and the capacity loss during the charge and discharge process is irreversible, which also limits its application in sodium-ion batteries to a certain extent.

[0005] Unlike carbon-based anodes that work through an insertion / deinsertion mechanism, metal / alloy anodes store energy by reacting with sodium ions to form alloys. The reaction formula can be expressed as xNa⁺ + M = Na x This mechanism gives the alloy material significant theoretical capacity, high electronic conductivity, and safe operating voltage, making it extremely attractive for use in sodium-ion battery anodes.

[0006] Among numerous alloy-based anode materials, lead (Pb) stands out. It's one of the most recyclable metals, with a recovery rate exceeding 99% in lead-acid battery systems. It's also inexpensive and readily available. However, the widespread use of lead-acid batteries also presents serious environmental challenges, with toxic lead emissions posing a significant threat to the ecological environment. Therefore, recycling lead from spent lead-acid batteries is both a challenging task and holds enormous economic value.

[0007] Lead can form Na with sodium 15Lead (Pb4) binary alloys, with high sodium storage capacity (gravimetric capacity of 485 mAh / g and volumetric capacity of 5480 mAh / cm³), also possess ideal redox potentials, making them excellent candidates for sodium-ion battery anode materials. However, lead-based alloy anode materials face a significant volume change during charge-discharge cycling, with fluctuations as high as 365%. This dramatic volume change can lead to severe material pulverization, resulting in loss of electrical contact between the active material and the current collector. This can trigger the formation of an unstable solid electrolyte interface (SEI), ultimately leading to significant battery capacity degradation and limiting the practical application of lead-based alloy anode materials in sodium-ion batteries. Summary of the Invention

[0008] The present invention provides a sodium ion battery negative electrode material based on recycled lead. The material exhibits excellent cycle stability and coulombic efficiency in sodium ion batteries, thereby solving the problems faced by the application of lead-based negative electrode materials in sodium ion batteries and improving the adaptability of the material in sodium ion batteries.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: It is prepared by the following preparation method: A. The metal lead recovered from the fully discharged waste lead-acid batteries is atomized into lead powder; B. mixing the prepared lead powder with metal M and carbon material and ball milling the mixture to obtain a composite material; wherein the metal M is one or more of Bi, Sn, Sb, Ni, Co, Cu, and Fe; C. mixing the prepared composite material with a battery negative electrode material additive to prepare a slurry; D. Apply the prepared slurry onto aluminum foil and dry it.

[0010] In the above technical scheme, a more specific technical scheme can also be: in step C, scheme one: the battery negative electrode material auxiliary agent includes a conductive agent and a binder, and the mass ratio of the composite material to the conductive agent and the binder is composite material: conductive agent: binder = 8:1:1; scheme two: the battery negative electrode material auxiliary agent includes a binder, and the mass ratio of the composite material to the binder is composite material: binder = 9:1.

[0011] Furthermore, the carbon material is one or more of carbon nanotubes, graphene, biomass hard carbon, acetylene black, and soft carbon.

[0012] Furthermore, the stoichiometric ratio of the lead powder to the metal M is PbM x , x=0~9.

[0013] Furthermore, the carbon material addition ratio is 0 to 10 wt%.

[0014] Furthermore, the particle size of the lead powder is 0.5 μm to 10 μm.

[0015] Furthermore, the particle size of the metal M is 0.5 μm to 10 μm.

[0016] Furthermore, the composite material has a particle size of 1 μm to 5 μm.

[0017] Furthermore, the specific method of drying in step D is: first drying at 100° C. to 120° C. under normal pressure for 1 h to 3 h, and then vacuum drying at 80° C. for 6 h to 12 h.

[0018] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. To address the problems faced by lead-based sodium-ion battery anode materials, such as large volume changes and poor cycle performance, the present invention provides a recycled lead-based composite anode material suitable for sodium-ion battery applications. This aims to address the problems faced by lead-based anode materials in sodium-ion batteries and improve the material's adaptability in sodium-ion batteries.

[0019] 2. After in-depth research, the present invention innovatively uses recycled lead as raw material, pulverizes it, and combines it with metal M and carbon materials using a ball milling method. This unexpected synergy can be achieved, which can adapt to the application requirements of sodium-ion batteries. It can solve the problems faced by sodium-ion batteries, such as low negative electrode capacity, complex and unstable raw material sources with poor consistency, and potential safety hazards, and can significantly improve the performance of sodium-ion batteries.

[0020] 3. In the present invention, the atomization characteristics of the recovered lead are further combined with the ball milling process of metal M and carbon materials to synergistically improve the adaptability of sodium ion batteries. Studies have shown that the atomization structure of metallic lead can be adapted to the application of sodium ion batteries. In addition, it also helps to synergize with the ball milling method to form a composite structure of lead, metal M and carbon materials, improve its particle size, dispersion distribution state, exposure behavior of active sites and structural stability, and then through a dual mechanism, synergistically enhance the adaptability of the material to sodium ion batteries and improve the performance of sodium ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a comparative example - the cycle diagram of Pb powder as the negative electrode material of sodium ion battery at a current density of 100mA / g.

[0022] Figure 2 This is a cycle diagram of Example 1 - PbBi composite metal powder as a negative electrode material for sodium ion batteries at a current density of 100 mA / g.

[0023] Figure 3 This is Example 2 - Cycle diagram of PbBi-G as a negative electrode material for sodium ion batteries at a current density of 100 mA / g. DETAILED DESCRIPTION

[0024] An optional preparation method for recycling lead-based negative electrode active materials of the present invention comprises the following steps: a) The metallic lead recovered from fully discharged waste lead-acid batteries is placed in a crucible and heated for insulation. A protective gas is filled into the atomization chamber and the cooling chamber. The dust collecting blower is started to maintain a slight negative pressure. The lead liquid valve is opened for atomization. The lead powder is collected and prepared by atomization, and sieved to obtain lead powder with a particle size of 0.5 μm to 10 μm. The furnace temperature is maintained at 400°C to 600°C, the protective gas is one of N2 and Ar, and the negative pressure in the cooling chamber is 10 Pa to 100 Pa. The atomization powder preparation time is 150 s to 300 s. b) Mix lead powder, metal M and carbon material in proportion and ball mill them. The atmosphere of the ball mill is one of the protective gases such as N2 and Ar. The ball milling time is 10 minutes to 60 minutes. The metal M is one or more of Bi, Sn, Sb, Ni, Co, Cu and Fe. The stoichiometric ratio of lead powder to metal M is PbM x , x=0-9; the carbon material is one or more of carbon nanotubes, graphene, biomass hard carbon, acetylene black, and soft carbon, and the addition ratio of the carbon material is 0wt%-10wt%; before ball milling, the particle size of the metal M is 0.5μm-10μm; c) sieving the ball milled product to obtain a composite material with a particle size of 1 μm to 5 μm; d) The composite material and the battery negative electrode material additive are fully stirred (stirring time is 4 hours to 12 hours) in proportion to prepare a slurry; wherein, in one embodiment, the battery negative electrode material additive includes a conductive agent and a binder, and the mass ratio of the composite material to the conductive agent and the binder is composite material:conductive agent:binder = 8:1:1; in another embodiment, the battery negative electrode material additive includes a binder, and the mass ratio of the composite material to the binder is composite material:binder = 9:1; e) coating the slurry onto aluminum foil and drying the slurry to obtain a negative electrode for a sodium ion battery. The specific drying method is as follows: first drying the slurry at 100° C. to 120° C. under normal pressure for 1 h to 3 h, and then vacuum drying the slurry at 80° C. for 6 h to 12 h.

[0025] The present invention is further described below with reference to examples: Comparative Example The recovered lead ingots are placed in the crucible of the atomization device, then heated to 500°C and maintained at this temperature for 1 hour. After that, the atomization valve is opened to allow nitrogen to fill the atomization chamber and the cooling chamber. At the same time, the dust collection fan is started to ensure that the inside of the cooling chamber maintains a negative pressure of 50 Pa. Next, the liquid flow valve is opened and the atomization powder making process is carried out for 200 seconds. After completion, the obtained lead powder is collected, and through the screening step, lead powder with a particle size of less than 1 micron is selected and collected.

[0026] The resulting lead powder was mixed with Ketjen Black and PVDF in a ratio of 8:1:1. NMP was added and stirred for 6 hours to form a slurry. The slurry was then coated onto aluminum foil and dried in an oven at 100°C for 2 hours, followed by vacuum drying at 80°C for 12 hours to produce an electrode sheet. This was then tested in a glove box using a half-cell with sodium metal.

[0027] Performance test: After the lead powder electrode and metallic sodium are combined into a half-battery, the charge and discharge test is performed. Figure 1 The first-cycle charge capacity of the half-cell is 406.20 mAh / g, the first-cycle discharge capacity is 571.80 mAh / g, and the first-cycle coulombic efficiency is 71.04%. The figure clearly shows that the capacity decreases and then increases during the initial cycle, reaching a peak of 425.60 mAh / g before gradually decreasing. After 90 cycles, the remaining capacity is 369.60 mAh / g, with a retention rate of 86.84%.

[0028] Example 1 The recovered lead ingots are placed in the crucible of the atomization device, then heated to 500°C and maintained at this temperature for 1 hour. After that, the atomization valve is opened to allow nitrogen to fill the atomization chamber and the cooling chamber. At the same time, the dust collection fan is started to ensure that the inside of the cooling chamber maintains a negative pressure of 50 Pa. Next, the liquid flow valve is opened and the atomization powder making process is carried out for 200 seconds. After completion, the obtained lead powder is collected, and through the screening step, lead powder with a particle size of less than 1 micron is selected and collected.

[0029] Lead powder and metallic Bi powder were mixed in a 1:1 atomic ratio and placed in a spherical ink tank. The tank was then placed in a glove box and filled with Ar gas. After sealing, the tank was removed from the glove box and milled in a high-energy ball mill with n-heptane as an additive for 10 minutes. The product was removed and vacuum-dried to obtain a metal powder. The powder was then sieved to obtain a PbBi composite metal powder with a particle size of less than 1 micron.

[0030] The resulting PbBi composite metal powder was mixed with Ketjen Black and PVDF in a ratio of 8:1:1. NMP was added and stirred for 6 hours to form a slurry. The slurry was then coated onto aluminum foil and dried in an oven at 100°C for 2 hours, followed by vacuum drying at 80°C for 12 hours to produce an electrode sheet. This was then tested in a glove box using a sodium metal half-cell.

[0031] Performance test: After the PbBi composite electrode and metal sodium are combined into a half-cell, the charge and discharge test is carried out. Figure 2 The first-cycle charge capacity of the half-cell is 595.40 mAh / g, the first-cycle discharge capacity is 642.80 mAh / g, and the first-cycle coulombic efficiency is 92.63%. The figure clearly shows that the capacity decreases and then increases during the initial cycle, reaching a peak of 588.60 mAh / g before gradually decreasing. After 100 cycles, the remaining capacity is 551.40 mAh / g, with a retention rate of 93.68%.

[0032] Example 2 Lead powder with a particle size of less than 1 μm was prepared according to the method of Example 1.

[0033] Lead powder and metallic Bi powder were mixed in a 1:1 atomic ratio. 2 wt% graphene was added. After mixing thoroughly, the mixture was transferred to a spherical ink tank. The tank was then placed in a glove box and filled with Ar gas. After sealing, the tank was removed from the glove box and milled in a high-energy ball mill with n-heptane as an additive for 10 minutes. The product was removed and vacuum-dried to obtain a composite material powder. The powder was then sieved to obtain a PbBi-G composite material with a particle size of less than 1 micron.

[0034] The resulting PbBi-G was mixed with Ketjen Black and PVDF in a ratio of 8:1:1. NMP was added and stirred for 6 hours to form a slurry. The slurry was then coated onto aluminum foil and dried in an oven at 100°C for 2 hours, followed by vacuum drying at 80°C for 12 hours to obtain an electrode sheet. This was then tested in a glove box as a half-cell with sodium metal.

[0035] Performance test: After the PbBi-G electrode and metal sodium are combined into a half-cell, the charge and discharge test is carried out. Figure 3 As can be seen, the first-cycle charge capacity of the half-cell is 560.90 mAh / g, the first-cycle discharge capacity is 682.30 mAh / g, and the first-cycle coulombic efficiency is 82.22%. It is clear from the figure that the cycling capacity gradually decreases from the second cycle, reaching a peak of 557.40 mAh / g in the second cycle, and then gradually decreases. After 100 cycles, the capacity remains at 514.60 mAh / g, with a retention rate of 92.32%.

[0036] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A sodium ion battery negative electrode material based on recycled lead, characterized in that Prepared by the following preparation method: A. The metal lead recovered from the fully discharged waste lead-acid batteries is atomized into lead powder; B. mixing the prepared lead powder with metal M and carbon material and ball milling the mixture to obtain a composite material; wherein the metal M is one or more of Bi, Sn, Sb, Ni, Co, Cu, and Fe; C. mixing the prepared composite material with a battery negative electrode material additive to prepare a slurry; D. Apply the prepared slurry onto aluminum foil and dry it.

2. The sodium ion battery negative electrode material based on recycled lead according to claim 1, characterized in that: In step C, the battery negative electrode material additives include a conductive agent and a binder, and the mass ratio of the composite material to the conductive agent and the binder is composite material: conductive agent: binder = 8:1:

1.

3. The sodium ion battery negative electrode material based on recycled lead according to claim 1, characterized in that: In step C, the battery negative electrode material additive includes a binder, and the mass ratio of the composite material to the binder is composite material: binder=9:

1.

4. The sodium ion battery negative electrode material based on recycled lead according to claim 1, 2 or 3, characterized in that: The carbon material is one or more of carbon nanotubes, graphene, biomass hard carbon, acetylene black, and soft carbon.

5. The negative electrode material for sodium ion batteries based on recycled lead according to claim 4, characterized in that: The stoichiometric ratio of lead powder to metal M is PbM x , x=0~9.

6. The sodium ion battery negative electrode material based on recycled lead according to claim 5, characterized in that: The carbon material addition ratio is 0-10 wt %.

7. The sodium ion battery negative electrode material based on recycled lead according to claim 6, characterized in that: The particle size of the lead powder is 0.5 μm to 10 μm.

8. The sodium ion battery negative electrode material based on recycled lead according to claim 7, characterized in that: The particle size of the metal M is 0.5 μm to 10 μm.

9. The sodium ion battery negative electrode material based on recycled lead according to claim 8, characterized in that: The particle size of the composite material is 1 μm to 5 μm.

10. The sodium ion battery negative electrode material based on recycled lead according to claim 9, characterized in that The specific method of step D drying is: First dry at 100℃~120℃ under normal pressure for 1h~3h, then vacuum dry at 80℃ for 6h~12h.

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