A method for preparing aqueous zinc ion battery material based on recycled lead paste

Abstract

The invention belongs to the field of batteries, and discloses a preparation method of aqueous zinc ion battery materials based on recycled lead paste, comprising the following steps: 1) dismantling waste lead-acid batteries, physically separating and extracting lead paste; 2) subjecting the lead paste to mechanical ball milling to obtain lead paste particles; 3) removing moisture from the lead paste particles to obtain dehydrated lead paste; 4) fully mixing and stirring the dehydrated lead paste with a conductive agent and a binder to obtain zinc ion battery slurry; 5) rolling the zinc ion battery slurry with a roller press to obtain a thin sheet active electrode; 6) rolling and compounding the thin sheet active electrode onto a metal grid current collector to obtain an aqueous zinc ion battery active electrode. The invention solves the problems of complex processing technology, high cost, high energy consumption, high pollution and low recovery rate after extracting lead paste from waste lead-acid batteries, and provides a method for directly extracting lead paste for a new green aqueous energy storage battery system.

Description

Technical Field

[0001] The invention relates to the field of batteries, and in particular to a method for preparing an aqueous zinc ion battery material based on recycled lead paste. Background Art

[0002] Lead-acid battery is a mature battery system. Today, it still occupies a huge share of the battery market and is widely used in electric bicycles, automobile lighting ignition, emergency backup battery systems for communication equipment, etc. Compared with other battery systems, the advantages of lead-acid batteries are that they are rich in resources and low in manufacturing cost, high in operating safety, and relatively mature in recycling technology. Although the traditional scrap lead smelting recycling technology is relatively mature, the pollution of waste lead acid still occurs from time to time. Therefore, green recycling processes such as hydrometallurgy and electrodeposition reduction are increasingly attracting attention. The most widely used hydrometallurgical method, including pretreatment, desulfurization, reduction and electrodeposition processes, can avoid the emission pollution problems of SO2 and lead dust. However, the energy efficiency of the electrodeposition process is low, and the total energy consumption is higher than that of the traditional pyrometallurgical process. From recycling to the final production of secondary lead, a series of steps are involved, and the efficiency of each step will eventually affect the total recycling efficiency, and the complex multi-process recycling has high technical requirements, which further increases the difficulty of recycling lead-acid batteries in backward countries and regions.

[0003] In view of the shortcomings of traditional smelting recovery technology and hydrometallurgical technology, we need to develop a more environmentally friendly and green way to recycle waste lead paste. In recent years, aqueous zinc-ion batteries have become a research hotspot in the field of electrochemical energy storage due to their low cost, environmental friendliness, high safety, and fast charging. Zinc-ion batteries have the advantages of high energy density, high power density, efficient and safe discharge process, non-toxic and cheap battery materials, and simple preparation process. They have high application value and development prospects in large-scale energy storage and other fields. The most important thing is that its electrolyte system uses the same sulfate anion as lead-acid batteries, which is highly compatible with the material system of lead-acid batteries. Summary of the invention

[0004] The invention aims to solve the problems of complex processing technology, high cost, high energy consumption, high pollution and low recovery rate after extracting lead paste from waste lead-acid batteries, and provide a preparation method of aqueous zinc ion battery material based on recycled lead paste.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for preparing an aqueous zinc ion battery material based on recycled lead paste comprises the following steps:

[0007] 1) Dismantle the used lead-acid batteries after they are fully discharged, physically separate and extract the solid waste of lead paste in the battery electrodes, and obtain the deactivated materials in the positive and negative electrodes, the main components of which are water, lead sulfate, and a small amount of metallic lead and lead oxide;

[0008] 2) The lead paste is subjected to a simple mechanical ball milling method to obtain uniform and refined black lead paste particles;

[0009] 3) Dry the black lead paste particles in a forced air drying oven at 80-100°C for 12-13 hours to remove moisture from the lead paste to obtain dehydrated lead paste;

[0010] 4) Fully mixing the dehydrated lead paste, the conductive agent and the binder to obtain zinc ion battery slurry;

[0011] 5) Roll the zinc ion battery slurry with a roller press to obtain a thin active electrode with a thickness of about 70 microns, and place it in a vacuum drying oven at 75-80° C. for 6-7 hours;

[0012] 6) Roll-pressing the above-mentioned thin active electrode onto a metal grid current collector to obtain an active electrode for an aqueous zinc ion battery.

[0013] In step 4), the conductive agent is acetylene black and the binder is polytetrafluoroethylene emulsion.

[0014] In step 4), the mass ratio of the dehydrating agent, the conductive agent and the binder is 7:2:1.

[0015] In step 4), the stirring time is 30-40 minutes.

[0016] In step 1), the byproducts of the waste lead-acid battery recycling process may also be used to replace the lead paste solid waste extracted by physical separation of the waste lead-acid batteries.

[0017] The present invention provides a new utilization method for recycling lead paste, which can recycle lead paste in a more environmentally friendly way and use the recycled lead paste as a positive electrode material for an aqueous zinc ion battery, which exhibits a flat charge and discharge platform as well as good cycle performance and a long life.

[0018] Compared with the prior art, the present invention has the following benefits:

[0019] (1) The present invention provides a new way to recycle lead paste, thereby avoiding environmental pollution problems such as lead dust and harmful gases generated during the recycling process of lead-acid batteries.

[0020] (2) The present invention achieves efficient recovery of lead paste, reduces the recovery cost of lead-acid batteries, and has significant economic benefits.

[0021] (3) The present invention provides a new choice for aqueous rechargeable zinc ion battery electrode materials and has the advantage of low cost, which is convenient for large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly describe the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods;

[0023] Figure 1 This is an XRD diagram of the lead paste obtained by disassembling a lead-acid battery in an embodiment of the present invention.

[0024] Figure 2 This is a SEM image of the lead paste obtained by disassembling a lead-acid battery in an embodiment of the present invention.

[0025] Figure 3 This is a cycle curve of lead paste as a zinc ion electrode material at a current density of 0.1A in an embodiment of the present invention.

[0026] Figure 4 The figure is a charge and discharge curve diagram of the lead paste as the positive electrode material of the zinc ion battery at a current density of 0.1A in the embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. The implementation cases described are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0028] Example 1 Recycling lead paste

[0029] The used lead-acid batteries are disassembled after being fully discharged, and the solid waste lead paste in the battery electrodes is physically separated and extracted to obtain the deactivated materials in the positive and negative electrodes, the main components of which are water, lead sulfate and a small amount of metallic lead and lead oxide.

[0030] In this embodiment, waste lead paste on the battery electrode plate is obtained by disassembling waste lead-acid batteries, and the crystal phase structure of the recycled waste lead paste is identified by a powder diffractometer (Rigaku MinFlex II), and the X-ray source is a Cu Kα radiation source with a wavelength of λ=1.5406Å. The morphology of the recycled lead paste powder is analyzed by a field emission scanning electron microscope (FESEM; Hitachi, SU-8010), and the battery performance is tested by a LAND battery test system (LAND CT2001A).

[0031] like Figure 1As shown in the XRD spectrum, the three strong peaks of the XRD spectrum of the lead paste powder obtained by disassembling the battery correspond to the standard card of PbSO4. The results show that the main phase of the lead paste is PbSO4. The product in the example is further characterized by SEM. Figure 2 It can be seen that the morphology of the lead paste is irregular and the particle size is large, so the particle size can be reduced and homogenized by simple mechanical ball milling.

[0032] Example 2 Preparation of positive electrode materials

[0033] 1) The lead paste recovered in the embodiment is subjected to a simple mechanical ball milling method to obtain uniform and refined black lead paste particles;

[0034] 2) Dry the black lead paste particles in a forced air drying oven at 80-100°C for 12-13 hours to remove moisture from the lead paste to obtain dehydrated lead paste;

[0035] 3) Mix the dehydrated lead paste with acetylene black and polytetrafluoroethylene emulsion in a mass ratio of 7:2:1, stir for 30 minutes, and mix thoroughly to obtain a zinc ion battery slurry;

[0036] 4) The zinc ion battery slurry is rolled using a roller press to obtain a thin sheet active electrode with a thickness of about 70 microns, and then placed in a vacuum drying oven and dried at 80° C. for 6 hours;

[0037] 5) The above-mentioned thin active electrode sheet was rolled onto a titanium mesh current collector and cut into electrode sheets with a diameter of 10 mm. The active material loading was controlled at 1.5-2.5 mg.

[0038] In the test, a circular zinc foil with a thickness of 0.1 mm was used as a reference and counter electrode, a Whatman glass fiber separator was used, and 2M zinc sulfate was used as the electrolyte. The battery was installed in the following order: positive battery shell - positive electrode sheet - separator (appropriate amount of electrolyte) - zinc foil - nickel foam - negative battery shell, and then pressed using a battery packaging machine to complete the preparation.

[0039] The prepared battery was subjected to constant current charge and discharge tests to observe the electrochemical behavior during the charge and discharge process. Figure 3 It can be seen that at a current density of 0.1A / g, the specific capacity of the battery gradually increases during the initial cycle, which may be related to the activation of the electrode material. At about the 75th cycle, the battery reaches a maximum specific capacity of 97.7mAh / g. After 300 cycles, the capacity retention rate is 80%, and the Figure 4 , we can see that the battery still has a flat charge and discharge platform after a long cycle, and the polarization difference of the battery is small.

[0040] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing an aqueous zinc ion battery material based on recycled lead paste, characterized in that: The steps include: 1) Dismantle the used lead-acid batteries after they are fully discharged, and physically separate and extract the lead paste in the battery electrodes, the main components of which are water, lead sulfate, and a small amount of metallic lead and lead oxide; 2) Mechanically ball mill the lead paste to obtain lead paste particles; 3) Drying the lead paste particles to remove moisture and obtain dehydrated lead paste; 4) The dehydrated lead paste is fully mixed with the conductive agent and the binder in a mass ratio of 7:2:1 to obtain a zinc ion battery slurry; wherein the conductive agent is acetylene black and the binder is polytetrafluoroethylene emulsion; 5) rolling the zinc ion battery slurry with a roller press to obtain a thin sheet active electrode, and drying it; 6) Roll-pressing the dried active electrode sheet onto a metal grid current collector to obtain an active electrode for an aqueous zinc ion battery.

2. A method for preparing an aqueous zinc ion battery material based on recycled lead paste according to claim 1, characterized in that: The drying in step 3) is carried out in a forced air drying oven at 80-100° C. for 12-13 hours.

3. The method for preparing an aqueous zinc ion battery material based on recycled lead paste according to claim 1, characterized in that: In step 4), the stirring time is 30-40 minutes.

4. The method for preparing an aqueous zinc ion battery material based on recycled lead paste according to claim 1, characterized in that: The drying in step 5) is carried out in a vacuum drying oven at 75-80°C for 6-7 hours.

5. The method for preparing an aqueous zinc ion battery material based on recycled lead paste according to claim 1, characterized in that: In step 1), the byproduct of the waste lead-acid battery recycling process is used instead of the lead paste extracted by physical separation of the waste lead-acid batteries.

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