CN108376789A - A method for recycling waste alkaline manganese batteries into primary zinc-air batteries - Google Patents

Abstract

The invention discloses a new method for making primary zinc-air batteries by recycling waste alkaline zinc-manganese batteries. In the method, the positive electrode discharge product of the alkaline manganese battery is collected, and after simple pickling and heat treatment steps, the processed final product obtained can be directly used as the positive electrode active material of the air battery. The invention has the advantages of simple operation, low energy consumption, environmental protection and high output. The obtained discharge product does not require complex treatment process, has good electrocatalytic activity for oxygen reduction reaction, and can be successfully applied to the air electrode of zinc-air battery. The assembled zinc-air battery has high specific capacity and specific energy, which significantly increases the waste alkali The added value of reuse of non-toxic zinc-manganese batteries is conducive to resource conservation and sustainable development.

Description

A method for recycling waste alkaline manganese batteries into primary zinc-air batteries

technical field

The invention relates to the field of resource recycling and battery technology, in particular to a method for recycling waste alkaline zinc-manganese batteries into primary zinc-air batteries.

Background technique

my country is a big country in battery production and consumption, among which the sales volume of alkaline zinc-manganese batteries was close to 4 billion in 2015. According to national policy requirements, my country's dry batteries have basically achieved mercury-free production. In 2003, the former State Environmental Protection Administration and relevant departments jointly issued the "Waste Battery Pollution Prevention and Control Technology Policy", which proposed that the focus of waste battery pollution control is waste mercury-containing batteries, waste lead-acid batteries, etc.; in the absence of technical and economic conditions for effective recycling , it is difficult to centrally collect disposable batteries. Therefore, a large number of waste alkaline manganese batteries are discarded randomly every year, which not only causes environmental problems, but also causes a huge waste of resources. If it is not recycled, it is difficult to achieve sustainable development.

Aiming at the recycling of waste batteries, there have been extensive studies and reports, mainly after the batteries are broken, and the metals and compounds in the batteries are separated and recovered through physical and chemical reactions, including hydrometallurgy and pyrometallurgy. These methods have problems such as complex process and high cost, and require high energy consumption in the recycling process, and even cause secondary pollution.

Metal-air batteries have high theoretical specific capacity and energy density, and their application prospects are outstanding. Among them, zinc-air battery is currently the only large-scale commercial metal-air battery system, and it has attracted more and more attention due to its high safety and low cost. After simple treatment, the positive electrode product of alkaline zinc-manganese battery is mainly manganese oxide. Tests show that this manganese oxide has good oxygen reduction (ORR) catalytic activity, so it can be used as an air electrode catalyst for zinc-air batteries. The operation mode of this method has high added value, which provides a new idea for the recycling and reuse of waste alkaline manganese batteries, and also shows potential application value.

Contents of the invention

The purpose of the present invention is to provide a brand-new idea of battery recycling. After simple collection and treatment, the positive electrode discharge product in the waste alkaline zinc-manganese battery can be used as the positive electrode catalyst of the primary zinc-air battery to realize high value-added utilization. Compared with the traditional recovery method, the method has the advantages of novel method, simple process and low energy consumption.

Technical scheme of the present invention:

A method for recycling waste alkaline zinc-manganese batteries as primary zinc-air batteries, the product after simple treatment of the positive electrode of the discharged alkaline zinc-manganese batteries has good oxygen reduction (ORR) catalytic performance and can be used as zinc Catalysts for air batteries.

The method for reclaiming the waste alkaline zinc-manganese battery as a primary zinc-air battery comprises the following steps:

(1) Acquisition and treatment of materials: after discharge treatment, the commercially available alkaline zinc-manganese batteries were mechanically disassembled, and the positive electrode discharge products were collected, stirred and dipped in dilute hydrochloric acid, filtered, and washed several times with ultrapure water to Neutral, collect the insoluble matter; dry the insoluble matter in an oven; then calcinate in the air atmosphere to obtain the final product;

(2) Test the oxygen reduction (ORR) performance: take the finished product and mix it with conductive carbon and grind it evenly, then add the binder and dispersant dropwise, and ultrasonicate for 30 minutes to obtain a uniformly dispersed slurry; pipette 9 μL of the slurry and drop it on the glassy carbon electrode As the working electrode, the platinum sheet was used as the counter electrode, and the saturated calomel electrode was used as the reference electrode, and a three-electrode system was assembled to test its oxygen reduction performance;

(3) Making the positive electrode of the battery: Mix the final product with conductive carbon and grind it evenly with a mortar, then add the binder dropwise, add ethanol, heat and stir until the solution is evaporated to dryness, and obtain a sticky solid mass, which is used The glass tube is rolled into a thin sheet, which is the catalytic layer; the catalytic layer, the current collector and the air diffusion layer are pressed together by a roller press as the positive electrode of the zinc-air battery; the catalytic layer and the air diffusion layer are respectively located on the two sides of the current collector. side;

(4) Assembly and testing of Zn-air batteries: Zn-air batteries were assembled with the composite electrode prepared above as the positive electrode, KOH as the electrolyte, and Zn as the negative electrode, and the assembled Zn-air batteries were electrochemically tested with the Land system.

The battery recovered in step (1) is an alkaline zinc-manganese battery, its shape includes but not limited to cylindrical and cuboid, and its size includes but not limited to No. 5 and No. 7 batteries; the concentration of hydrochloric acid is 0.5-3mol L ^-1 , The drying temperature is 60-100°C; the calcination temperature is 200-300°C, and the calcination time is 2-6h.

Conductive additive in described step (2) is Vulcan XC-72 or super P or graphite; Binding agent is Nafion or PTFE or PVDF, and dispersion solvent is Virahol, and the mass ratio range of catalyst and conductive additive is 2: 8 to 5:5, the volume ratio of 5 wt% binder dispersion to isopropanol ranges from 1:10 to 1:30.

Conductive carbon in described step (3) is Vulcan XC-72, super P and graphite, binder is polytetrafluoroethylene i.e. PTFE solution, solvent is ethanol, and dispersant is Virahol; Manganese dioxide, conductive carbon The mass ratio to PTFE is 6:13:1-19:19:2; the active material load is 5-10 mg cm ^-2 ; the current collector is nickel foam.

The KOH concentration in the step (4) is 6mol/L, and 0.2mol/LZnO is added; the zinc negative electrode is zinc paste; the assembled zinc-air battery includes but is not limited to 2032 type, A675 type or self-made grinding with battery.

Advantages of the present invention: Aiming at the problems of complex process, high equipment requirements and high energy consumption in the process of separating and smelting different metals or metal compounds in the battery in the traditional waste battery recycling method, the present invention proposes a brand new recycling idea, which will The positive electrode product of the discharged alkaline zinc-manganese battery can be used as the positive electrode catalyst of the zinc-air battery after simple treatment, so the process is relatively simple, the cost is low, energy saving and environmental protection, and it has important practical value in the field of alkaline manganese waste battery treatment.

Description of drawings

Fig. 1 is the recovery flow chart of waste zinc-manganese battery of the present invention.

What Fig. 2 embodiment 1 is to process the XRD figure of final product.

What Fig. 3 embodiment 1 is the SEM figure of processing final product.

What Fig. 4 embodiment 1 is to process the _N2 adsorption-desorption curve of final product.

Fig. 5 is the linear scanning polarization curve of the treated end product of Example 1 and the Pt/C catalyst in 0.1 mol L ^-1 KOH at 1600 rpm.

Fig. 6 is the Tafel slope curve fitted from the polarization curve between the treated end product of Example 1 and the Pt/C catalyst.

7 is the discharge curve of the zinc-air battery assembled in Example 1.

Detailed ways

Example 1:

Flow chart of the present invention is as shown in Figure 1, and the recovery processing method of waste zinc-manganese battery of the present invention, it comprises the following steps:

(1) A commercially available AA battery was discharged to 0.8V with a current of 20mA, and then mechanically disassembled to collect the positive discharge product. The collected product was stirred and soaked in 0.5mol L ^-1 dilute hydrochloric acid for 3 minutes, filtered, and washed several times with ultrapure water to neutrality, then dried in an oven at 80°C, and then calcined in an air atmosphere at 250°C 4 hours. The XRD pattern of the obtained treated final product is shown in FIG. 2 , and its main component is manganese dioxide (ε-MnO ₂ ) in epsilon phase. The scanning electron micrograph is shown in Figure 3, which is a relatively loose block structure. The N ₂ adsorption-desorption curve is shown in Figure 4, and the specific surface area is about 46m ² g ^-1 .

(2) Test the oxygen reduction (ORR) performance: Take the final product and Vulcan XC-72 and grind it evenly at a mass ratio of 4:6, add 50 μL Nafion and 950 μL isopropanol dropwise, and disperse evenly by ultrasonication for 30 minutes. Carbon electrodes were dried naturally in an ethanol atmosphere. The performance test of the catalyst adopts a three-electrode system, the electrolyte is 0.1mol L ^-1 KOH solution, and the instrument used is a double constant potential electrochemical workstation (AFCBP1, Pine Instrument). Figure 5 shows the treatment of the final product as an electrocatalyst at 1600rpm, 5mV s Linear scanning polarization curves at ^-1 and compared with commercial Pt/C. The figure shows that the final product of this treatment exhibits an oxygen reduction performance similar to that of Pt/C.

Figure 6 is a Tafel slope curve for treating the final product as an electrocatalyst. The figure shows that the catalyst has a Tafel slope similar to that of Pt/C at both low and high potentials, proving its excellent catalytic kinetics.

(3) Assembling and testing of battery cathode and zinc-air battery: take conductive additive and polytetrafluoroethylene (PTFE) binder with a mass ratio of 3:7, and disperse them in ethanol, stir and heat until ethanol evaporates to dryness, Rolling the obtained dough into sheets is the air diffusion layer. Take conductive carbon: end product of treatment: polytetrafluoroethylene (PTFE) as a mass ratio of 12:7:1 for sampling, add 2mL of ethanol, stir and heat until the solution is evaporated to dryness, and roll the resulting dough into sheets as a catalytic layer (Loading capacity is about 10 mgcm ^-2 ). Take the above catalyst layer 1cm×1cm, foam nickel and air diffusion layer and roll them together with a roller press, as the positive electrode of the zinc-air battery. Wherein the manganese dioxide catalyst layer and the air diffusion layer are respectively located on both sides of the nickel foam.

(4) Assembly and testing of zinc-air battery: 2032-type button-type zinc-air battery was assembled with the catalytic layer as the positive electrode, 6mol L ^- 1 KOH added with 0.2mol L ^{- 1} ZnO as the electrolyte, filter paper as the diaphragm, and zinc paste as the negative electrode 17 holes with a radius of about 1 mm are uniformly drilled in the positive electrode shell with an electric drill in advance. Figure 7 is the discharge curve of the assembled zinc-air battery. As shown in the figure, the open circuit voltage of this air battery is about 1.40V, and when the current density is 10mAcm ^-2 , the discharge voltage remains stable, and the capacity of 675mAh and the energy of 810mWh can be released. Usually, the mass of the positive electrode active material in a No. 5 alkaline-manganese battery is about 10g, and a spent alkaline-manganese battery can be converted into 1000 button-type zinc-air batteries, and it is estimated that the total capacity of 675Ah and the total capacity of 810Wh can be obtained. energy. Therefore, this method of converting waste alkaline-manganese batteries into zinc-air batteries has high added value and broad application prospects.

Claims (6)

1. A method for reclaiming waste and old alkaline zinc-manganese batteries as primary zinc-air batteries, characterized in that: the product of the positive electrode of the discharged alkaline zinc-manganese batteries has good oxygen reduction (ORR) catalysis after simple treatment properties, it can be used as a positive electrode catalyst for zinc-air batteries. 2. The method for reclaiming waste and used alkaline zinc-manganese batteries as claimed in claim 1 as a primary zinc-air battery, comprising the following steps: (1) Acquisition and treatment of materials: after discharge treatment, the commercially available alkaline zinc-manganese batteries were mechanically disassembled, and the positive electrode discharge products were collected, stirred and dipped in dilute hydrochloric acid, filtered, and washed several times with ultrapure water to Neutral, collect the insoluble matter; dry the insoluble matter in an oven; then calcinate in the air atmosphere to obtain the final product; (2) Test the oxygen reduction (ORR) performance: take the finished product and mix it with conductive carbon and grind it evenly, then add the binder and dispersant dropwise, and ultrasonicate for 30 minutes to obtain a uniformly dispersed slurry; pipette 9 μL of the slurry and drop it on the glassy carbon electrode As the working electrode, the platinum sheet was used as the counter electrode, and the saturated calomel electrode was used as the reference electrode, and a three-electrode system was assembled to test its oxygen reduction performance; (3) Making the positive electrode of the battery: Mix the final product with conductive carbon and grind it evenly with a mortar, then add the binder dropwise, add ethanol, heat and stir until the solution is evaporated to dryness, and obtain a sticky solid mass, which is used The glass tube is rolled into a thin sheet, which is the catalytic layer; the catalytic layer, the current collector and the air diffusion layer are pressed together by a roller press as the positive electrode of the zinc-air battery; the catalytic layer and the air diffusion layer are respectively located on the two sides of the current collector. side; (4) Assembly and testing of Zn-air batteries: Zn-air batteries were assembled with the composite electrode prepared above as the positive electrode, KOH as the electrolyte, and Zn as the negative electrode, and the assembled Zn-air batteries were electrochemically tested with the Land system. 3. The method for recycling waste alkaline zinc-manganese batteries as a primary zinc-air battery as claimed in claim 2, characterized in that: the battery recovered in step (1) is an alkaline zinc-manganese battery, and its shape includes but is not limited to Cylindrical and cuboid, the size of which includes but not limited to batteries No. 5 and No. 7; the concentration of hydrochloric acid is 0.5-3mol L ^-1 , the drying temperature is 60-100°C; the calcination temperature is 200-300°C, and the calcination time is 2- 6h. 4. The method for reclaiming waste alkaline zinc-manganese batteries as claimed in claim 2 as a primary zinc-air battery, characterized in that: the conductive additive in the step (2) is Vulcan XC-72 or super P or graphite; The binder is Nafion or PTFE or PVDF, the dispersion solvent is isopropanol, and the mass ratio of the catalyst to the conductive additive ranges from 2:8 to 5:5, and the volume ratio of 5wt% binder dispersion to isopropanol The range is 1:10 to 1:30. 5. the waste and old alkaline zinc-manganese battery reclaiming as claimed in claim 2 is used as the method for primary zinc-air battery, it is characterized in that: the conductive carbon in the described step (3) is Vulcan XC-72, super P and graphite, The binder is polytetrafluoroethylene (PTFE solution), the solvent is ethanol, and the dispersant is isopropanol; the mass ratio of manganese dioxide, conductive carbon and PTFE is 6:13:1-19:19:2; The amount is 5-10 mg cm ^-2 ; the current collector is nickel foam. 6. The method for reclaiming waste batteries as claimed in claim 2 as a primary zinc-air battery, characterized in that: the KOH concentration in the step (4) is 6mol/L, and 0.2mol/L ZnO is added; The zinc anode is zinc paste; the assembled zinc-air battery includes but is not limited to 2032 type, A675 type or self-made abrasive battery.