Method for preparing manganous-manganic oxide positive electrode material by using manganese ore tailing leachate and application of manganous-manganic oxide positive electrode material

Abstract

The invention discloses a method for preparing a manganous-manganic oxide (Mn3O4) positive electrode material by using a manganese ore tailing leaching solution and application of the manganous-manganic oxide (Mn3O4) positive electrode material. The manganese ore tailing leaching solution is directly used as a raw material, resource utilization of manganese in the manganese ore tailing leaching solution is achieved through a two-step precipitation method, the manganous-manganic oxide positive electrode material with the high additional value and the high performance is obtained, and meanwhile iron in the leaching solution is separated and enriched. The method is simple and convenient, the yield is high, preparation conditions are easy to control, the method is suitable for large-scale production, and the prepared manganous-manganic oxide electrode material has a special flower-cluster-shaped morphology and more oxygen defects, so that the manganous-manganic oxide electrode material has high reversible specific capacity and better cycling stability and rate capability when being used as an aqueous zinc ion battery positive electrode material.

Description

Technical Field

[0001] The present invention relates to the technical field of positive electrode materials for aqueous zinc ion batteries, and in particular to a method for preparing manganese tetraoxide (Mn3O4) positive electrode materials by utilizing manganese ore tailings leaching solution and application thereof. Background Art

[0002] Manganese ore is a major strategic key mineral in short supply in my country. With the rapid development of society, my country's demand for manganese ore resources has grown rapidly, but the exploitable high-grade manganese ore is becoming increasingly exhausted, so low-grade manganese ore has become the main source of manganese products. At the same time, with the continuous development and utilization of manganese ore resources, a large amount of tailings have been produced. However, the current utilization rate of manganese ore tailings is not high. In recent years, aqueous zinc-ion batteries (ZIBs) have attracted more and more attention due to their high theoretical capacity, low cost, simple process, and good safety. Manganese oxide cathode materials have the advantages of low cost, high redox potential, and low toxicity, and are considered to be one of the most promising cathode materials. However, due to the poor conductivity and easy dissolution of manganese oxide in electrolytes, its zinc storage performance is seriously affected. In recent years, researchers have developed a series of modification methods, such as morphology control, doping, composite carbon materials, and construction of oxygen defects. In addition, the preparation of commercial manganese oxide cathode materials currently mainly uses pure reagents as raw materials, with relatively high preparation costs and relatively complex preparation methods. From the perspective of practical application, the development of a low-cost, simple method for preparing high-performance manganese oxide positive electrode materials is of great significance for the large-scale application of manganese oxides in ZIBs. To this end, the present invention proposes a method for directly preparing manganese tetraoxide (Mn3O4) positive electrode materials for aqueous zinc ion batteries from manganese ore tailings leachate. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing manganese tetraoxide positive electrode material by utilizing manganese ore tailings leaching solution and its application.

[0004] The specific steps are:

[0005] (1) reducing and leaching the manganese ore tailings to obtain a manganese ore tailings leaching solution;

[0006] (2) 25 mL of the manganese ore tailings leaching solution obtained in step (1) was measured and placed in a beaker, and 1 mol / L ammonia solution was added dropwise to the beaker under stirring at room temperature to adjust the pH value of the solution to 7, the precipitate was kept in the mother liquor, and aged at room temperature for 12 hours, followed by liquid-solid separation;

[0007] (3) continuing to dropwise add 1 mol / L ammonia solution to the liquid obtained after the liquid-solid separation in step (2) to adjust the pH value of the solution to 9.6, keeping the precipitate in the mother liquor and aging it at room temperature for 12 hours, then centrifuging and freeze-drying the precipitate to obtain a self-oxidized manganese tetraoxide material;

[0008] (4) The manganese tetraoxide obtained in step (3) is annealed at 200°C to 300°C for 3 hours in an argon atmosphere to obtain a final manganese tetraoxide positive electrode material.

[0009] The prepared manganese tetraoxide positive electrode material can be used to prepare high-performance aqueous zinc ion batteries.

[0010] Advantages of the present invention: The present invention directly utilizes manganese ore tailings leachate as raw material, realizes resource utilization of manganese in manganese ore tailings leachate through a two-step precipitation method, obtains high value-added manganese tetraoxide positive electrode material, and simultaneously separates and enriches iron in the leachate. The method of the present invention is simple, has high yield, and is easy to control preparation conditions, and is suitable for large-scale production. The prepared manganese tetraoxide electrode material has a special flower cluster morphology and more oxygen defects, and as a positive electrode material for aqueous zinc ion batteries, it has high reversible specific capacity, good cycle stability and rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is the XRD spectrum of the manganese tetraoxide positive electrode material prepared in Examples 1 to 3.

[0012] Figure 2 This is the SEM spectrum of the manganese tetraoxide positive electrode material prepared in Example 1.

[0013] Figure 3 This is the SEM spectrum of the manganese tetraoxide positive electrode material prepared in Example 2.

[0014] Figure 4 This is the SEM spectrum of the manganese tetraoxide positive electrode material prepared in Example 3.

[0015] Figure 5 This is the electron paramagnetic resonance (EPR) spectrum of the manganese tetraoxide positive electrode material prepared in Examples 1 to 3.

[0016] Figure 6 This is a rate performance diagram of the manganese tetraoxide positive electrode material prepared in Examples 1 to 3.

[0017] Figure 7 This is a cycle performance diagram of the manganese tetraoxide positive electrode material prepared in Examples 1 to 3. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with specific embodiments. It should be pointed out that the following embodiments are for those skilled in the art to better understand the present invention, rather than limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above content.

[0019] Embodiment 1:

[0020] (1) reducing and leaching the manganese ore tailings to obtain a manganese ore tailings leaching solution;

[0021] (2) 25 mL of the manganese ore tailings leaching solution obtained in step (1) was measured and placed in a beaker, and 1 mol / L ammonia solution was added dropwise to the beaker under stirring at room temperature to adjust the pH value of the solution to 7, the precipitate was kept in the mother liquor, and aged at room temperature for 12 hours, followed by liquid-solid separation;

[0022] (3) Add 1 mol / L ammonia solution to the liquid obtained after liquid-solid separation in step (2) to adjust the pH value of the solution to 9.6, keep the precipitate in the mother liquor, and age it at room temperature for 12 hours, then centrifuge and freeze-dry the precipitate to obtain a self-oxidized manganese tetraoxide positive electrode material.

[0023] Embodiment 2:

[0024] (1) reducing and leaching the manganese ore tailings to obtain a manganese ore tailings leaching solution;

[0025] (2) 25 mL of the manganese ore tailings leaching solution obtained in step (1) was measured and placed in a beaker, and 1 mol / L ammonia solution was added dropwise to the beaker under stirring at room temperature to adjust the pH value of the solution to 7, the precipitate was kept in the mother liquor, and aged at room temperature for 12 hours, followed by liquid-solid separation;

[0026] (3) continuing to dropwise add 1 mol / L ammonia solution to the liquid obtained after the liquid-solid separation in step (2) to adjust the pH value of the solution to 9.6, keeping the precipitate in the mother liquor and aging it at room temperature for 12 hours, then centrifuging and freeze-drying the precipitate to obtain a self-oxidized manganese tetraoxide material;

[0027] (4) The manganese tetraoxide obtained in step (3) was annealed at 200° C. for 3 hours in an argon atmosphere to obtain a final manganese tetraoxide positive electrode material.

[0028] Embodiment 3:

[0029] (1) reducing and leaching the manganese ore tailings to obtain a manganese ore tailings leaching solution;

[0030] (2) 25 mL of the manganese ore tailings leaching solution obtained in step (1) was measured and placed in a beaker, and 1 mol / L ammonia solution was added dropwise to the beaker under stirring at room temperature to adjust the pH value of the solution to 7, the precipitate was kept in the mother liquor, and aged at room temperature for 12 hours, followed by liquid-solid separation;

[0031] (3) continuing to dropwise add 1 mol / L ammonia solution to the liquid obtained after the liquid-solid separation in step (2) to adjust the pH value of the solution to 9.6, keeping the precipitate in the mother liquor and aging it at room temperature for 12 hours, then centrifuging and freeze-drying the precipitate to obtain a self-oxidized manganese tetraoxide material;

[0032] (4) The manganese tetraoxide obtained in step (3) was annealed at 300° C. for 3 hours in an argon atmosphere to obtain a final manganese tetraoxide positive electrode material.

[0033] Electrochemical performance test: The Mn3O4 positive electrode material prepared in the example was used as the active material, conductive carbon black (SuperP) as the conductive agent, and polyvinylidene fluoride (PVDF) as the binder were mixed and ground evenly in a mass ratio of 7:2:1, and then an appropriate amount of N-methyl-2-pyrrolidone (NMP) was added. After being mixed into a slurry, it was evenly coated on a stainless steel foil, vacuum dried at 80 °C for 12 hours, and punched into 1 cm 2 The electrode sheet obtained after punching was used as the working electrode, the metal zinc sheet was used as the counter electrode, the glass fiber membrane (GF / D) was used as the diaphragm, and the mixture of 2.0 mol / L ZnSO4 and 0.5 mol / L MnSO4 was used as the electrolyte. The CR2025 button cell was assembled in air. The constant current charge and discharge performance of the battery was tested using the BTS-5V / 10mA charge and discharge tester of Shenzhen Xinwei Company, and the charge and discharge voltage range was 0.8~1.9 V. Before the rate performance and cycle performance tests, the battery was heated to 0.15 A g -1 The current density of the rate performance test was 0.2 A g -1 , 0.5 A g -1 , 1 A g -1 , 2 A g -1 , 3A g -1 , 2 A g -1 , 1 A g -1 , 0.5 A g -1 , 0.2 A g -1 , and 5 cycles were performed at each current density. The cycle performance test was performed at 0.5 A g -1 The current density was 250 cycles.

[0034] like Figure 1The XRD patterns of the Mn3O4 cathode materials prepared in Examples 1 to 3 are shown. As can be seen from the figure, the phase of the material prepared by the present invention is Mn3O4. As the argon annealing temperature increases (200 to 300°C), the crystallinity of the obtained Mn3O4 cathode material gradually increases.

[0035] like Figure 2~Figure 4 , which is a SEM image of the Mn3O4 positive electrode material prepared in Examples 1 to 3. It can be seen from the figure that the Mn3O4 positive electrode materials prepared in Examples 1 to 3 are all composed of flower-like micron sheets and nanoparticles.

[0036] like Figure 5 , which is the electron paramagnetic resonance (EPR) spectrum of the Mn3O4 positive electrode materials prepared in Examples 1 to 3. It can be seen from the figure that the Mn3O4 positive electrode materials prepared in Examples 1 to 3 all have oxygen defects, among which the Mn3O4 positive electrode material prepared in Example 3 contains relatively the most oxygen defects.

[0037] like Figure 6 As shown in FIG. 1 , the rate performance curves of the Mn3O4 positive electrode materials prepared in Examples 1 to 3 are shown. As can be seen from the figure, the Mn3O4 positive electrode materials prepared in Examples 1 to 3 have very good rate performance. Among them, the rate performance of the Mn3O4 positive electrode material prepared in Example 3 is the best: at a current density of 0.2 A g -1 , 0.5 A g -1 , 1 A g -1 , 2 A g -1 and 3Ag -1 Under the condition of high-temperature quenching, the discharge / charge specific capacity is 904.5 / 926.7 mAh g -1 、728.6 / 721.6 mAh g -1 、406.7 / 388.1 mAh g -1 、207.2 / 190.2 mAh g -1 and 114.2 / 104.9mAh g -1 .

[0038] like Figure 7 As shown in the figure, the cycle performance curves of the Mn3O4 positive electrode materials prepared in Examples 1 to 3 are shown. It can be seen from the figure that the Mn3O4 positive electrode materials prepared in Examples 1 to 3 have good cycle stability, among which the cycle performance of Example 3 is relatively optimal. The discharge / charge specific capacities of the Mn3O4 positive electrode materials prepared in Examples 1 to 3 are 74.2 / 76.1 mAhg when they are cycled to 250 cycles. -1 、132.1 / 130.2 mAh g -1 and 247.1 / 247.2 mAh g -1。

Claims

1. A method for preparing manganese tetraoxide positive electrode material using manganese ore tailings leaching solution, characterized in that: The specific steps are: (1) reducing and leaching the manganese ore tailings to obtain a manganese ore tailings leaching solution; (2) 25 mL of the manganese ore tailings leaching solution obtained in step (1) was measured and placed in a beaker, and 1 mol / L ammonia solution was added dropwise to the beaker under stirring at room temperature to adjust the pH value of the solution to 7, the precipitate was kept in the mother liquor, and aged at room temperature for 12 hours, followed by liquid-solid separation; (3) continuing to dropwise add 1 mol / L ammonia solution to the liquid obtained after the liquid-solid separation in step (2) to adjust the pH value of the solution to 9.6, keeping the precipitate in the mother liquor and aging it at room temperature for 12 hours, then centrifuging and freeze-drying the precipitate to obtain a self-oxidized manganese tetraoxide material; (4) The manganese tetraoxide obtained in step (3) is annealed at 200°C to 300°C for 3 hours in an argon atmosphere to obtain a final manganese tetraoxide positive electrode material.

2. An application of the manganese tetraoxide positive electrode material prepared by the method according to claim 1, characterized in that: The manganese tetraoxide positive electrode material is applied to positive electrode materials of aqueous zinc ion batteries.

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