Method for rapidly preparing lithium and sodium ion battery negative electrode from waste sodium electrode plate

Abstract

The invention relates to a method for rapidly preparing a negative electrode of a lithium and sodium ion battery from a waste sodium electrode plate. Comprising the following steps: (1) respectively disassembling a Prussian blue positive pole piece, a hard carbon negative pole piece and a diaphragm in a sodium-electricity waste soft package, and soaking in deionized water; (2) respectively standing the solution obtained in the step (1), centrifuging, and drying in a blast oven; (3) directly tabletting the Prussian blue positive electrode powder dried in the step (2) and a diaphragm, preparing a slurry from the hard carbon negative electrode powder and sodium alginate with the concentration of 2% according to a ratio of 98: 2, and drying in a vacuum oven at 90 DEG C for 12 hours; the problem that the waste soft package of the sodium battery is difficult to recycle is solved. The obtained negative electrode material realizes electrochemical performance close to that of a fresh negative electrode under the carbonization of a rapid Joule heat means.

Description

Technical Field

[0001] This invention relates to the field of sodium and lithium-ion battery anode materials, specifically to a method for rapidly preparing lithium and sodium-ion battery anodes from waste sodium electrode sheets. Background Technology

[0002] With the rapid growth of global demand for renewable energy and large-scale energy storage systems, sodium-ion batteries, due to their abundant sodium resources, low cost, and environmental friendliness, are considered an important supplement and alternative to lithium-ion batteries, and are gradually moving from laboratory applications to industrial applications. Among the many cathode materials for sodium-ion batteries, Prussian blue materials, with their open framework structure, high theoretical capacity, and ease of synthesis, have shown great application potential. However, with the large-scale application of sodium-ion batteries, the recycling of their waste pouch cells has become increasingly prominent. Traditional battery recycling methods, such as pyrometallurgy and hydrometallurgy, typically involve high-temperature smelting or strong acid leaching, which are complex, energy-intensive, and prone to secondary pollution. More importantly, these methods aim to recover metal elements, destroying the valuable microstructure of the positive and negative electrode materials, making it impossible to achieve high-value recycling of the materials. Therefore, developing a low-cost, high-efficiency, environmentally friendly technology for recycling and reusing waste sodium-ion battery pouch cells that can directly preserve the functional material structure has become a key problem urgently needing to be solved in this field.

[0003] The core component of sodium-ion batteries includes Prussian blue cathode, which, after proper processing, can be cleverly applied to lithium-ion battery systems, thereby achieving high-value reuse across systems from sodium batteries to lithium batteries.

[0004] Based on the above findings, this invention innovatively proposes a novel recycling strategy: the Prussian blue cathode material disassembled from waste sodium-ion pouch batteries is treated using a highly efficient Joule heating method to remove surface contaminants, repair the interface, and restore its electrochemical activity. The regenerated anode material is then directly used to assemble high-performance lithium-ion batteries.

[0005] This method eliminates the complex chemical processes and material structure damage involved in traditional recycling, enabling the direct, efficient, and high-value reuse of sodium-ion battery materials in lithium-ion battery systems, thus opening up a completely new technical path for solving the recycling problem of sodium-ion batteries. Summary of the Invention

[0006] The purpose of this invention is to provide a method for rapidly preparing lithium and sodium-ion battery anodes from waste sodium electrode sheets, addressing existing problems. This method has advantages such as low cost, speed, high efficiency, sustainability, and environmental friendliness. Furthermore, this method can be used to prepare materials with electrochemical performance similar to fresh electrode sheets.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows: A method for rapidly preparing lithium-ion battery anodes from waste sodium electrode sheets includes the following steps: Step (1): Disassemble the positive electrode (Prussian blue), negative electrode (hard carbon), and diaphragm in the sodium battery waste soft pack and soak them in deionized water. Step (2): Let the solution obtained in step (1) stand, then centrifuge and dry it in a forced-air oven; Step (3): The dried positive electrode (Prussian blue) powder and the separator from step (2) are directly pressed into tablets, while the negative electrode (hard carbon) powder and binder (2% sodium alginate) are mixed in a ratio of 98:2 to form a slurry and dried in a vacuum oven at 90°C for 12 hours. Step (4): The positive electrode and separator prepared in step (3) are heated to 2000 ℃ at a heating rate of 50 ℃ / s in a vacuum environment of 10 Pa and held at that temperature for 0 s. The negative electrode pretreated in step (3) is heated to 2800 ℃ at a heating rate of 50 ℃ / s in a vacuum environment of 10 Pa and held at that temperature for 0 s to obtain fresh hard carbon negative electrode material; Step (5): The positive electrode powder treated with Joule heating effect in step (4) is used with lithium sheet and 1M LiPF6 (EC+DMC volume ratio 1:1) electrolyte to assemble a lithium-ion battery. The negative electrode powder treated with Joule heating effect is used with sodium sheet and 1M NaPF6 (EC+DMC volume ratio 1:1) electrolyte to assemble a sodium-ion battery.

[0008] Furthermore, the membrane pretreatment on the positive electrode side of the waste soft-pack battery is prepared using the following steps: A certain mass of positive electrode and diaphragm is accurately weighed, and then tableted in a tablet press.

[0009] Furthermore, the pretreatment of the waste soft-pack negative electrode side is prepared by the following steps: A certain mass of waste negative electrode powder was accurately weighed and mixed with sodium alginate colloid at a concentration of 2% in a certain proportion. The slurry was then dried in a vacuum oven at a certain temperature for a certain period of time.

[0010] Preferably, the hard carbon material and sodium alginate colloid with a concentration of 2% are mixed in a ratio of 98:2, the vacuum oven temperature is 60℃-90℃, and the heating time is 6-12h.

[0011] Furthermore, the rapid Joule heating carbonization of the waste carbon material employs the following steps: The pretreated positive electrode, negative electrode, and separator were heated to different temperatures at a heating rate of 50 °C / s in a 10 Pa vacuum environment and held at these temperatures for different times to obtain hard carbon negative electrode material.

[0012] Preferably, the vacuum conditions are as follows: the inert atmosphere is nitrogen, argon, etc.; the vacuum environment pressure is 0.1-100 Pa; the heating device used includes, but is not limited to, a Joule furnace, graphite furnace, or other rapid heating device based on the Joule heating effect. The heat treatment heating rate is 0.1 ℃ / s-200 ℃ / s, the carbonization temperature is 400 ℃-3000 ℃, and the holding time is 0-180 min.

[0013] Compared with existing technologies, the method for rapidly preparing lithium-ion battery anodes from waste sodium electrode sheets described in this invention has the following advantages: This invention discloses a rapid synthesis method for hard carbon materials utilizing the Joule heating effect. Its key feature is that it uses discarded soft-pack batteries as a carbon source, solving the problem of difficult recycling of discarded soft-pack batteries from sodium-ion batteries. The advantages of using the Joule heating effect as a synthesis method include a rapid heating rate (≈200 ℃ / s), a wide temperature controllable range (400-3000 ℃), a short overall reaction time (minimum ≈1 min), simple operation, and effective regulation of the hard carbon material's structure while achieving rapid carbonization. When this hard carbon material is used as a negative electrode material in sodium-ion batteries, it exhibits electrochemical performance similar to that of fresh materials. Attached Figure Description

[0014] Figure 1 This is a rate capability diagram of Prussian blue material treated with the Joule heating effect in lithium-ion batteries.

[0015] Figure 2 This refers to the capacity retention of Prussian blue material treated with the Joule heating effect after 65 cycles in a lithium-ion battery.

[0016] Figure 3 These are XRD patterns of untreated and Joule-heat-treated Prussian blue materials.

[0017] Figure 4 The untreated and Joule-heat-treated sodium-ion battery hard carbon anode materials at 20 mAh g -1 Comparison of the first charge-discharge curves under current density.

[0018] Figure 5 These are XRD patterns of untreated and Joule-heated sodium-ion battery hard carbon anode materials.

[0019] Figure 6These are Raman diagrams of untreated and Joule-heated sodium-ion battery hard carbon anode materials. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0021] This experiment provides a method for rapidly preparing lithium-ion battery anodes from waste sodium electrode sheets, including the following steps: Step (1): Disassemble the positive electrode (Prussian blue), negative electrode (hard carbon), and diaphragm in the sodium battery waste soft pack and soak them in deionized water. Step (2): Let the solution obtained in step (1) stand for 12 hours, then centrifuge at 20,000 rpm for 5 min and dry in a forced-air oven at 90 ℃ for 12 hours; Step (3): The dried positive electrode (Prussian blue) powder and the separator from step (2) are directly pressed into tablets, while the negative electrode (hard carbon) powder and the binder (2% sodium alginate) are mixed in a ratio of 98:2 to form a slurry and dried in a vacuum oven at 90°C for 12 hours.

[0022] Step (4): The positive electrode and separator prepared in step (3) are heated to 2000 ℃ at a heating rate of 50 ℃ / s in a vacuum environment of 10 Pa and held at that temperature for 0 s. The negative electrode pretreated in step (3) is heated to 2800 ℃ at a heating rate of 50 ℃ / s in a vacuum environment of 10 Pa and held at that temperature for 0 s to obtain fresh hard carbon negative electrode material.

[0023] Step (5): The positive electrode powder treated with Joule heating effect in step (4) is used with lithium sheet and 1M LiPF6 (EC+DMC volume ratio 1:1) electrolyte to assemble a lithium-ion battery. The negative electrode powder treated with Joule heating effect is used with sodium sheet and 1M NaPF6 (EC+DMC volume ratio 1:1) electrolyte to assemble a sodium-ion battery.

[0024] It should be noted that: After the Joule heating reaction, the positive electrode material was prepared into a slurry with a mass ratio of active material to binder (2% sodium alginate colloid) of 95:5 and uniformly coated onto copper foil. The slurry was then dried in a vacuum oven at 90 °C for 12 hours. The electrode sheets were cut using a 10 mm circular mold, weighed, and stored in a glove box filled with argon (Ar).

[0025] Lithium metal was used as the counter electrode, and 1M LiPF6 (EC+DMC volume ratio 1:1) was used as the electrolyte. The separator was a glass fiber membrane (GF / A). The half-cell was assembled in a glove box filled with argon (Ar). The assembled cell was then placed in a constant temperature oven at 25 °C for 12 hours.

[0026] After the Joule heating reaction, the negative electrode material was prepared into a slurry with a mass ratio of active material to binder (2% sodium alginate colloid) of 95:5 and uniformly coated onto aluminum foil. It was then dried in a vacuum oven at 90 °C for 12 hours. The electrode sheets were cut using a 10 mm circular mold, weighed, and stored in a glove box filled with argon (Ar).

[0027] Sodium metal was used as the counter electrode, and 1 M / L NaPF6 (EC + DMC volume ratio 1:1) was used as the electrolyte. A glass fiber membrane (GF / A) was used as the separator. The half-cell was assembled in a glove box filled with argon (Ar). The assembled cell was then incubated at 25 °C for 12 hours.

[0028] The cycle and rate performance of half-cells were tested using the Newway battery testing system.

[0029] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, or substitutions made without departing from the spirit and principle of the present invention are also permitted.

Claims

1. A method for rapidly preparing lithium-ion battery anodes from waste sodium electrode sheets, characterized in that, Includes the following steps: Step 1: Disassemble the Prussian blue positive electrode, hard carbon negative electrode, and diaphragm from the sodium battery waste soft pack and soak them in deionized water. Step 2: Let the solutions obtained in Step 1 stand, then centrifuge and dry them in a forced-air oven; Step 3: The dried Prussian blue cathode powder and separator from Step 2 are directly compressed into tablets, while the hard carbon anode powder and 2% sodium alginate are mixed in a ratio of 98:2 to form a slurry, which is then dried in a vacuum oven at 90 ℃ for 12 hours. Step 4: The positive electrode and separator prepared in Step 3 are heated to 2000 ℃ at a heating rate of 50 ℃ / s in a vacuum environment of 10 Pa and then cooled naturally; the negative electrode pretreated in Step 3 is heated to 2800 ℃ at a heating rate of 50 ℃ / s in a vacuum environment of 10 Pa and then cooled naturally to obtain fresh hard carbon negative electrode material. Step 5: The positive electrode powder treated with Joule heating effect in Step 4 is used to assemble a lithium-ion battery with lithium sheets, 1M LiPF6 electrolyte, and EC+DMC volume ratio of 1:

1. The negative electrode powder treated with Joule heating effect is used to assemble a sodium-ion battery with sodium sheets, 1M NaPF6 electrolyte, and EC+DMC volume ratio of 1:

1.

2. The method for rapidly preparing lithium-ion battery anodes from waste sodium electrode sheets according to claim 1, characterized in that, The solution should be left to stand for 6-12 hours in step 2.

3. The method for rapidly preparing lithium-ion battery anodes from waste sodium electrode sheets according to claim 1, characterized in that, In step 2, the centrifugation time is 2-10 minutes each time, and the rotation speed is 500-20000 rpm.

4. The method for rapidly preparing lithium-ion battery anodes from waste sodium electrode sheets according to claim 1, characterized in that, In step 2, the heating temperature of the forced-air drying oven is 60-90 ℃, and the drying time is 6-12 h.

5. The method for rapidly preparing lithium-ion battery anodes from waste sodium electrode sheets according to claim 1, characterized in that, The vacuum environment has a pressure of 0.1-100 Pa; the heating devices used include Joule furnaces and graphite furnaces, which are rapid heating devices based on the Joule heating effect.

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