A manganese-based cathode material for zinc-ion batteries, its preparation method and application

Abstract

This invention discloses a manganese-based cathode material for zinc-ion batteries, its preparation method, and its application. The cathode material is a composite material formed by adding a metaborate-based compound to a manganese-based oxide. The metaborate-based compound includes at least one of seven compounds: lithium metaborate, sodium metaborate, potassium metaborate, iron metaborate, magnesium metaborate, manganese metaborate, and aluminum metaborate. The manganese-based oxide includes at least one of nine compounds: α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, T-MnO2, λ-MnO2, Mn2O3, Mn3O4, and ZnMn2O4. The metaborate ion can react on the surface of the manganese-based cathode material to form a boron-containing protective layer, thereby inhibiting the excessive formation of by-reaction products and manganese dissolution. This enhances the structural stability of the manganese-based cathode material and improves its cycle and rate performance in zinc-ion batteries.

Description

Technical Field

[0001] This invention relates to the field of zinc-ion battery materials technology, and in particular to a manganese-based cathode material for zinc-ion batteries, its preparation method, and its application. Background Technology

[0002] Given the dwindling supply of traditional fossil fuels and the growing demand for flexible and wearable portable batteries, there is an urgent need to discover cleaner and more environmentally friendly energy storage devices. Although lithium-ion batteries (LIBs) have been widely adopted in the market, they still face limitations such as limited capacity, high cost, high risk, and insufficient cleanliness, which hinder their further development.

[0003] Zinc-ion battery energy storage systems boast excellent theoretical capacity (819 mAh g⁻¹). -1 High energy density (5851 mAh / cm³) -3 The advantages of aqueous zinc-manganese batteries, such as suitable redox potential, abundant natural resources, and mild aqueous electrolytes, facilitate commercial production by avoiding demanding manufacturing processes, thereby significantly reducing costs. With the increasing demand for portable and flexible devices, coupled with the ongoing research into gel-based electrolytes, flexible aqueous zinc-manganese batteries are gradually becoming a development trend. In conclusion, aqueous zinc-ion batteries, as a novel environmentally friendly energy storage component, have significant research potential.

[0004] Currently, the structural instability of manganese-based cathode materials in zinc-ion batteries and the excessive formation of byproducts have become decisive factors limiting the development of zinc-ion batteries. Therefore, developing more stable novel cathode materials and suppressing the formation of byproducts are key to the development of zinc-ion batteries. Layered manganese dioxide has advantages such as being environmentally friendly, economical, having high operating voltage, and large theoretical capacity, making it a promising cathode material for aqueous zinc batteries. However, it faces challenges such as narrow interlayer spacing, poor structural stability, low conductivity, and excessive deposition of the discharge byproduct Zn4SO4(OH)6·5H2O on the cathode surface. These problems lead to rapid capacity decay and poor cycle stability in practical applications, severely hindering the application of manganese-based cathode materials in high-performance aqueous zinc-ion batteries. Therefore, selecting appropriate methods to adjust the structure of manganese-based cathode materials to improve their electrochemical performance is a research direction of great practical significance.

[0005] To address the issues of capacity decay, structural instability, and excessive byproduct deposition in manganese-based cathode materials, previous extensive experimental research and theoretical analysis indicate that these problems are primarily caused by structural instability, excessive manganese dissolution, and excessive byproduct deposition during charge-discharge processes. Structural instability leads to poor reversibility in manganese-based cathode materials; the original structure collapses during charge-discharge, preventing the normal transport of zinc and hydrogen ions. Excessive manganese dissolution reduces reactive materials, severely hindering battery capacity. Excessive byproduct deposition also impedes the effective transport of various active materials in the electrolyte and the reversibility of the battery. Therefore, the overall structural degradation of the material during charge-discharge severely affects the performance stability of the electrode material; however, currently, there is no simple and effective method to improve these defects. Summary of the Invention

[0006] This solution addresses the problems and needs raised above by proposing a manganese-based cathode material for zinc-ion batteries, its preparation method, and its application. The above-mentioned technical objectives are achieved by adopting the following technical features, and several other technical benefits are also brought about.

[0007] One object of the present invention is to propose that the positive electrode material is a composite material formed by adding a metaboric acid-based compound to a manganese-based oxide, wherein the metaboric acid-based compound includes at least one of seven: lithium metaborate, sodium metaborate, potassium metaborate, iron metaborate, magnesium metaborate, manganese metaborate, and aluminum metaborate; and the manganese-based oxide includes at least one of nine: α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, T-MnO2, λ-MnO2, Mn2O3, Mn3O4, and ZnMn2O4.

[0008] In addition, the zinc-ion battery manganese-based cathode material according to the present invention may also have the following technical features:

[0009] Another object of the present invention is to provide a method for preparing a manganese-based cathode material for zinc-ion batteries as described above, comprising the following steps:

[0010] S10: Under the action of mechanical stirring, the strong oxidant and manganese salt are put into a beaker, and deionized water is added and stirred evenly to form a mixed solution of manganese salt and oxidant.

[0011] S20: The above mixed solution of manganese salt and oxidant is transferred into a high-pressure reactor with a polytetrafluoroethylene liner, and then placed in an oven for heating;

[0012] S30: After cooling, precipitation, filtration and washing multiple times, it is placed in an oven for vacuum drying to obtain the precursor of manganese-based cathode material;

[0013] S40: Place the metaboronic acid compound in a beaker, add deionized water and stir to form a metaborate solution. Immerse the manganese-based cathode material precursor in the above metaborate solution and stir at room temperature.

[0014] S50: After the beaker is transferred into the oven for drying and evaporation, a manganese-based cathode material is obtained. During the process, a composite cathode material of manganese-based compound and metaboronic acid-based compound is formed.

[0015] In one example of the present invention, in step S10, the strong oxidant is a permanganate, a persulfate, or a peroxide.

[0016] In one example of the present invention, the strong oxidant is AMnO4, wherein A is at least one of six metal ions: Li, Na, K, Ca, Mg, and Zn; the persulfate is MS2O8, wherein M is at least one of three substances: NH4, Na, and K; and the peroxide is at least one of two substances: K2O2 and H2O2.

[0017] In one example of the present invention, in step S10, the manganese salt is at least one of manganese sulfate, manganese acetate, manganese chloride, and manganese carbonate.

[0018] In one example of the present invention, in step S30, after cooling, precipitation, filtration and washing multiple times, the precursor of manganese-based cathode material is obtained by vacuum drying in an oven at 80-110°C.

[0019] In one example of the present invention, in step S40, the metaboronic acid compound is RBO2, wherein R is at least one of seven substances: Li, Na, K, Fe, Mg, Mn, and Al.

[0020] In one example of the present invention, in step S40, the mass ratio of the manganese-based oxide to the metaboronic acid-based compound is 1:0.01~0.5.

[0021] In one example of the present invention, in step S50, the beaker is moved into an oven and dried and evaporated at 60-80°C to obtain a manganese-based cathode material, during which a composite cathode material of manganese-based compound and metaboronic acid-based compound is formed.

[0022] Another objective of this invention is to provide a method for preparing manganese-based cathode materials for zinc-ion batteries as described above, and to apply the cathode materials prepared by this method to the cathode materials of zinc-ion batteries.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This invention employs a simple solution method to treat the surface of manganese-based cathode materials, thereby forming a composite cathode material of manganese-based compounds and metaboronic acid-based compounds. This method is easy and convenient to operate, and metaboronic acid-based compounds are inexpensive and abundant, making them suitable for large-scale production and commercial applications, thus possessing significant practical value.

[0025] 2. The modification treatment with metaboric acid-based compounds in this invention also affects the charge-discharge reaction process of manganese-based cathode materials. Experimental applications revealed that a boron-containing protective layer (including MnBx, zinc borides, etc., where x is 1 / 2, 1, 2, etc.) reversibly forms on the surface of the manganese-based cathode material. These compounds accelerate ion diffusion by inhibiting excessive deposition of reaction byproducts, suppressing manganese dissolution, and thus enhancing the structural stability of the manganese-based cathode material, thereby improving the capacity and rate performance of zinc-ion batteries. Combining these advantages, it can be concluded that zinc-ion battery manganese-based cathode materials with added metaboric acid-based compounds have very broad application prospects, and developing them as cathode materials for zinc-ion batteries is of great practical significance.

[0026] The preferred embodiments of the invention will be described in more detail below with reference to the accompanying drawings, so as to facilitate an understanding of the features and advantages of the invention. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. The drawings are merely illustrative of some embodiments of the present invention and are not intended to limit the scope of the present invention to all embodiments.

[0028] Figure 1 These are transmission electron microscope images of the δ-MnO2 cathode material before and after treatment according to Example 1 of the present invention;

[0029] Figure 2 The X-ray diffraction patterns of the δ-MnO2 cathode material powder before and after treatment in Example 1 are shown.

[0030] Figure 3 XPS images of the δ-MnO2 cathode material before and after treatment in Example 1;

[0031] Figure 4 The image shows the XRD pattern of the δ-MnO2 cathode material after treatment during the charge and discharge process in Example 1.

[0032] Figure 5 The graphs show the cycling performance of the δ-MnO2 cathode material before and after treatment in Example 1, when used as cathodes at room temperature with current densities of 500, 1000, 2000 and 4000 mA / g, respectively. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0035] According to the first aspect of the present invention, the positive electrode material is a composite material formed by adding a metaboronic acid-based compound to a manganese-based oxide, wherein the metaboronic acid-based compound includes at least one of seven: lithium metaborate, sodium metaborate, potassium metaborate, iron metaborate, magnesium metaborate, manganese metaborate, and aluminum metaborate; and the manganese-based oxide includes at least one of nine: α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, T-MnO2, λ-MnO2, Mn2O3, Mn3O4, and ZnMn2O4.

[0036] The cathode material of this invention employs a simple solution method to treat the surface of manganese-based cathode materials, thereby forming a composite cathode material of manganese-based compounds and metaboronic acid-based compounds. This method is easy and convenient to operate, and metaboronic acid-based compounds are inexpensive and abundant, making them suitable for large-scale production and commercial applications, thus possessing significant practical value.

[0037] The modification treatment with metaboronic acid-based compounds in this invention also affects the charge-discharge reaction process of manganese-based cathode materials. Experimental applications revealed that a boron-containing protective layer (including MnBx, zinc borides, etc., where x is 1 / 2, 1, 2, etc.) reversibly forms on the surface of the manganese-based cathode material. These compounds accelerate ion diffusion by inhibiting excessive deposition of reaction byproducts, suppressing manganese dissolution, and thus enhancing the structural stability of the manganese-based cathode material, thereby improving the capacity and rate performance of zinc-ion batteries. Combining these advantages, it can be concluded that zinc-ion battery manganese-based cathode materials with added metaboronic acid-based compounds have very broad application prospects, and developing them as cathode materials for zinc-ion batteries is of great practical significance.

[0038] According to a second aspect of the present invention, a method for preparing a manganese-based cathode material for a zinc-ion battery as described above includes the following steps:

[0039] S10: Under the action of mechanical stirring, the strong oxidant and manganese salt are put into a beaker, and deionized water is added and stirred evenly to form a mixed solution of manganese salt and oxidant.

[0040] S20: The above mixed solution of manganese salt and oxidant is transferred into a high-pressure reactor with a polytetrafluoroethylene liner, and then placed in an oven for heating;

[0041] S30: After cooling, precipitation, filtration and washing multiple times, it is placed in an oven for vacuum drying to obtain the precursor of manganese-based cathode material;

[0042] S40: Place the metaboronic acid compound in a beaker, add deionized water and stir to form a metaborate solution. Immerse the manganese-based cathode material precursor in the above metaborate solution and stir at room temperature.

[0043] S50: After the beaker is transferred into the oven for drying and evaporation, a manganese-based cathode material is obtained. During the process, a composite cathode material of manganese-based compound and metaboronic acid-based compound is formed.

[0044] Specifically, S10: Under mechanical stirring, a strong oxidant and manganese salt are placed in a beaker, and 50-80 mL of deionized water is added and stirred for 0.5-1 h; S20: The above solution is transferred to a high-pressure reactor with a polytetrafluoroethylene liner, and then placed in an oven preheated to 120-200℃ and heated for 8-24 h; S30: After cooling, precipitation, filtration, and washing multiple times, the solution is placed in an oven at 80-110℃ for vacuum drying to obtain a manganese-based cathode material precursor; S40: A metaboronic acid compound is placed in a beaker, and 50-100 mL of deionized water is added and stirred for 0.5-1 h. The manganese-based cathode material precursor is then immersed in the above solution and stirred at room temperature for 0.5-1 h; S50: The beaker is transferred to an oven at 60-80℃ for drying and evaporation to obtain a manganese-based cathode material. During this process, a composite cathode material of manganese-based compound and metaboronic acid compound is formed.

[0045] For example, S10: Under mechanical stirring, a strong oxidant and manganese salt are placed in a beaker, and 60 mL of deionized water is added and stirred for 1 hour; S20: The above solution is transferred to a high-pressure reactor (100 mL) with a polytetrafluoroethylene liner, and then placed in an oven preheated to 160°C and heated for 12 hours; S30: After cooling, precipitation, filtration, and washing multiple times, the solution is placed in an oven at 110°C for vacuum drying to obtain a manganese-based cathode material precursor; S40: Lithium metaborate is placed in a beaker, 50 mL of deionized water is added and stirred for 30 min, and then the manganese-based cathode material precursor is immersed in the above solution and stirred at room temperature for 30 min; S50: The beaker is transferred to an oven and dried and evaporated at 80°C to obtain a manganese-based cathode material, during which a self-assembled protective layer is formed.

[0046] This preparation method utilizes the product of dissolving a metaboric acid-based compound in water to treat manganese-based cathode materials, forming a composite cathode material of manganese-based and metaboric acid-based compounds in aqueous solution. This process is simple and easy to operate and does not affect the main structure of the manganese-based cathode material. The reversible boron-containing protective layer formed during charge and discharge (including MnBx, zinc borides, etc., where x is 1 / 2, 1, 2, etc.) inhibits excessive deposition of by-products, forming a robust cathode-electrolyte interface framework, suppressing manganese ion dissolution, and significantly improving the cycle stability of the manganese-based cathode material. This preparation method is simple, easy to control, and has good reproducibility, enabling large-scale application. This preparation method is not limited to the materials disclosed in this invention and can also be used for the post-processing of other zinc-ion battery cathode materials. This method has significant application potential and broad application prospects.

[0047] In one example of the present invention, in step S10, the strong oxidant is a permanganate, a persulfate, or a peroxide.

[0048] In one example of the present invention, the strong oxidant is AMnO4, wherein A is at least one of six metal ions: Li, Na, K, Ca, Mg, and Zn; the persulfate is MS2O8, wherein M is at least one of three substances: NH4, Na, and K; and the peroxide is at least one of two substances: K2O2 and H2O2.

[0049] In one example of the present invention, in step S10, the manganese salt is at least one of manganese sulfate, manganese acetate, manganese chloride, and manganese carbonate.

[0050] In one example of the present invention, in step S30, after cooling, precipitation, filtration and washing multiple times, the precursor of manganese-based cathode material is obtained by vacuum drying in an oven at 80-110°C.

[0051] In one example of the present invention, in step S40, the metaboronic acid compound is RBO2, wherein R is at least one of seven substances: Li, Na, K, Fe, Mg, Mn, and Al.

[0052] In one example of the present invention, in step S40, the mass ratio of the manganese-based oxide to the metaboronic acid-based compound is 1:0.01~0.5.

[0053] In one example of the present invention, in step S50, the beaker is moved into an oven and dried and evaporated at 60-80°C to obtain a manganese-based cathode material, during which a composite cathode material of manganese-based compound and metaboronic acid-based compound is formed.

[0054] Another objective of this invention is to provide a method for preparing manganese-based cathode materials for zinc-ion batteries as described above, and to apply the cathode materials prepared by this method to the cathode materials of zinc-ion batteries.

[0055] In other words, the zinc-ion battery manganese-based cathode material with added metaboric acid compounds is used as a cathode material in the field of zinc-ion batteries or power batteries.

[0056] Specific Cases

[0057] Example 1: Post-treatment of δ-MnO2 cathode material with lithium metaborate

[0058] The original manganese-based cathode material was directly synthesized using a one-step hydrothermal method. Under mechanical stirring, 12 mmol of potassium permanganate and 2 mmol of manganese sulfate were placed in a beaker, and 60 mL of deionized water was added and stirred for 1 hour. The solution was then transferred to a 100 mL high-pressure reactor with a PTFE liner and heated in an oven preheated to 160°C for 12 hours. After cooling, the original manganese-based cathode material sample was obtained. This sample was further precipitated, filtered, and washed multiple times with deionized water before being vacuum dried in an oven at 110°C. A simple solution method was used to obtain the manganese-based cathode material with added lithium metaborate. 0.02 g of lithium metaborate was placed in a beaker, and 50 mL of deionized water was added and stirred for 30 min. Then, 0.5 g of the original manganese-based cathode material powder was immersed in the solution and stirred at room temperature for 30 min. Finally, the beaker was dried and evaporated at 80°C to obtain the manganese-based cathode material with added lithium metaborate. Figure 1 These are transmission electron microscope images of the samples before and after processing. This indicates the formation of a δ-MnO2@lithium metaborate composite cathode material. Figure 2 The X-ray diffraction patterns of the sample powder before and after processing show the structure and composition of the cathode material. Figure 3 XPS images of the samples before and after processing show that the crystal structure of the sample did not change after processing. Figure 4 The XRD images show the treated sample during charge and discharge. It can be seen that a reversible boron-containing protective layer (including MnBx, zinc borides, etc., with x values ​​of 1 / 2, 1, 2, etc.) was formed during the charge and discharge process. Electrochemical performance was tested using coin cells. The sample, conductive carbon black, and binder (polyvinylidene fluoride) were mixed in a mass ratio of 7:2:1, and an appropriate amount of solvent NMP (N-methylpyrrolidone) was added. After mixing into a slurry, it was uniformly coated onto titanium foil and vacuum dried at 110℃ to obtain the electrode. A zinc sheet was used as the counter electrode, and 2 mol·L⁻¹... -1 ZnSO4 and 0.1 mol·L -1 MnSO4 is used as the electrolyte, glass fiber filter paper is used as the diaphragm (GF-D), and the loading of active material is approximately 0.8-1.5 mg cm⁻¹. -2 The cells were assembled into 2032 coin cells in an air environment. A NEWARE TC53 battery testing system was used to perform charge-discharge tests at a constant current density. The charge-discharge voltage range was 0.8–1.8V, and the charge-discharge current densities were selected as 500, 1000, 2000, and 4000 mA / g, respectively. Figure 4 To test the obtained cycle characteristic curves, the capacities of the untreated cathode material after cycling at different current densities were 81.8 mAh / g, 84.2 mAh / g, 41.1 mAh / g, and 25.4 mAh / g, respectively. The capacities of the treated cathode material after cycling at different current densities were 229.5 mAh / g, 210.5 mAh / g, 101.2 mAh / g, and 95.2 mAh / g, respectively. The zinc-ion battery δ-MnO2 cathode material with added lithium metaborate exhibited excellent cycle performance and rate performance.

[0059] Example 2: Post-treatment of α-MnO2 cathode material with sodium metaborate

[0060] The original manganese-based cathode material was directly synthesized using a one-step hydrothermal method. Under mechanical stirring, 1 ml of 38 wt% concentrated hydrochloric acid was added to 45 ml of a 2.5 mmol potassium permanganate aqueous solution and stirred for 30 minutes. The solution was then transferred to a 100 mL high-pressure reactor with a polytetrafluoroethylene liner and heated in an oven preheated to 140 °C for 12 hours. After cooling, the original manganese-based cathode material sample was obtained. This sample was then further precipitated, filtered, and washed multiple times with deionized water before being vacuum dried in an oven at 80 °C. A simple solution method was used to obtain the manganese-based cathode material with added sodium metaborate. 0.02 g of sodium metaborate was placed in a beaker, and 50 mL of deionized water was added and stirred for 30 minutes. Then, 0.5 g of the original manganese-based cathode material powder was immersed in the solution and stirred at room temperature for 30 minutes. Finally, the beaker was transferred to an oven and dried and evaporated at 80 °C to obtain the manganese-based cathode material with added sodium metaborate. Transmission electron microscopy (TEM) images of the samples before and after treatment showed that the sample with added sodium metaborate formed an α-MnO2@sodium metaborate composite cathode material. X-ray diffraction (XRD) patterns of the powder samples before and after treatment showed that the structure and composition of the cathode material remained unchanged. XPS results showed the presence of a boron compound on the surface of the treated sample. XRD images of the treated sample during charge-discharge showed that the treated sample formed a reversible boron-containing protective layer (including MnBx, zinc borides, etc., with x values ​​of 1 / 2, 1, 2, etc.). Electrochemical performance was tested using coin cells. The sample, conductive carbon black, and binder (polyvinylidene fluoride) were mixed in a mass ratio of 7:2:1, and an appropriate amount of solvent NMP (N-methylpyrrolidone) was added. After mixing into a slurry, the mixture was uniformly coated onto titanium foil and vacuum-dried at 110°C to obtain the electrode sheet. A zinc sheet was used as the counter electrode, and 2 mol·L⁻¹... -1 ZnSO4 and 0.1 mol·L -1 MnSO4 is used as the electrolyte, glass fiber filter paper is used as the diaphragm (GF-D), and the loading of active material is approximately 0.8-1.5 mg cm⁻¹. -2The cells were assembled into 2032 coin cells in an air environment. A NEWARE TC53 battery testing system was used for charge-discharge testing at a constant current density. The charge-discharge voltage range was 0.8–1.8V, and the charge-discharge current densities were 500, 1000, 2000, and 4000 mA / g. After charge-discharge cycles (200 cycles at 500 mA / g, 300 cycles at 1000 mA / g, 800 cycles at 2000 mA / g, and 1000 cycles at 4000 mA / g) on ​​the untreated cathode material, the capacities were 135.2 mAh / g, 112.4 mAh / g, 88.5 mAh / g, and 74.8 mAh / g, respectively. The treated cathode materials exhibited capacities of 239.8 mAh / g, 212.6 mAh / g, 124.5 mAh / g, and 91.2 mAh / g after cycling at different current densities. The zinc-ion battery α-MnO2 cathode material with added sodium metaborate demonstrated excellent cycle performance and rate capability.

[0061] Example 3: Post-treatment of β-MnO2 cathode material with potassium metaborate

[0062] The original manganese-based cathode material was directly synthesized using a one-step hydrothermal method. Under mechanical stirring, 4 mmol of potassium persulfate and 4 mmol of manganese sulfate were placed in a beaker, and 70 mL of deionized water was added and stirred for 2 hours. The solution was then transferred to a 100 mL high-pressure reactor with a polytetrafluoroethylene liner and heated in an oven preheated to 140°C for 12 hours. After cooling, the original manganese-based cathode material sample was obtained. This sample was further precipitated, filtered, and washed multiple times with deionized water before being vacuum dried in an oven at 70°C. A simple solution method was used to obtain the manganese-based cathode material with potassium metaborate. 0.02 g of potassium metaborate was placed in a beaker, and 50 mL of deionized water was added and stirred for 30 min. Then, 0.5 g of the original manganese-based cathode material powder was immersed in the solution and stirred at room temperature for 30 min. Finally, the beaker was transferred to an oven and dried at 80°C to obtain the manganese-based cathode material with potassium metaborate. Transmission electron microscopy (TEM) images of the samples before and after treatment showed that the sample with added potassium metaborate formed a β-MnO2@potassium metaborate composite cathode material. X-ray diffraction (XRD) patterns of the powder samples before and after treatment showed that the structure and composition of the cathode material remained unchanged. XPS results showed the presence of a boron compound on the surface of the treated sample. XRD images of the treated sample during charge-discharge showed that the treated sample formed a reversible boron-containing protective layer (including MnBx, zinc borides, etc., with x values ​​of 1 / 2, 1, 2, etc.). Electrochemical performance was tested using coin cells. The sample, conductive carbon black, and binder (polyvinylidene fluoride) were mixed in a mass ratio of 7:2:1, and an appropriate amount of solvent NMP (N-methylpyrrolidone) was added. After mixing into a slurry, the mixture was uniformly coated onto titanium foil and vacuum-dried at 110°C to obtain the electrode sheet. A zinc sheet was used as the counter electrode, and 2 mol·L⁻¹... -1 ZnSO4 and 0.1 mol·L -1 MnSO4 is used as the electrolyte, glass fiber filter paper is used as the diaphragm (GF-D), and the loading of active material is approximately 0.8-1.5 mg cm⁻¹. -2The cells were assembled into 2032 coin cells in an air environment. A NEWARE TC53 battery testing system was used for charge-discharge testing at a constant current density. The charge-discharge voltage range was 0.8–1.8V, and the charge-discharge current densities were 500, 1000, 2000, and 4000 mA / g. After charge-discharge cycles (200 cycles at 500 mA / g, 300 cycles at 1000 mA / g, 800 cycles at 2000 mA / g, and 1000 cycles at 4000 mA / g) on ​​the untreated cathode material, the capacities were 121.2 mAh / g, 100.4 mAh / g, 75.5 mAh / g, and 62.8 mAh / g, respectively. The treated cathode materials exhibited capacities of 219.8 mAh / g, 202.3 mAh / g, 114.5 mAh / g, and 81.7 mAh / g after cycling at different current densities, respectively. The β-MnO2 cathode material for zinc-ion batteries with potassium metaborate addition demonstrated excellent cycle performance and rate capability.

[0063] Example 4: Post-treatment of λ-MnO2 cathode material with lithium metaborate

[0064] The original manganese-based cathode material was synthesized using a one-step hydrothermal method followed by calcination. Under mechanical stirring, 2.5 g of potassium permanganate and 1.5 g of manganese acetate were placed in a beaker, and 80 mL of deionized water was added and stirred for 30 minutes. The solution was then transferred to a 100 mL high-pressure reactor with a polytetrafluoroethylene liner and heated in an oven preheated to 160°C for 12 hours. After cooling, the mixture was precipitated, filtered, and washed multiple times with deionized water, then vacuum-dried in an oven at 80°C, and finally calcined at 450°C for 4 hours to obtain the original manganese-based cathode material sample. A simple solution method was used to obtain the manganese-based cathode material with added lithium metaborate. 0.02 g of lithium metaborate was placed in a beaker, and 50 mL of deionized water was added and stirred for 30 minutes. Then, 0.5 g of the original manganese-based cathode material powder was immersed in the solution and stirred at room temperature for 30 minutes. Finally, the beaker was dried and evaporated at 80°C in an oven to obtain manganese-based cathode material with added lithium metaborate. Transmission electron microscopy (TEM) images of the samples before and after treatment showed that the sample with added lithium metaborate formed a λ-MnO2@lithium metaborate compound composite cathode material. X-ray diffraction (XRD) patterns of the powder samples before and after treatment showed that the structure and composition of the cathode material remained unchanged. XPS results of the samples before and after treatment showed the presence of a boron compound on the surface of the treated sample. XRD images of the treated sample during charge and discharge showed that the treated sample formed a reversible boron-containing protective layer (including MnBx, zinc borides, etc., with x values ​​of 1 / 2, 1, 2, etc.). Electrochemical performance was tested using coin cells. The sample, conductive carbon black, and binder (polyvinylidene fluoride) were mixed at a mass ratio of 7:2:1, and an appropriate amount of solvent NMP (N-methylpyrrolidone) was added. After mixing into a slurry, the mixture was uniformly coated onto titanium foil and vacuum dried at 110°C to obtain the electrode sheet. Using a zinc sheet as the counter electrode, 2 mol·L -1 ZnSO4 and 0.1 mol·L -1 MnSO4 is used as the electrolyte, glass fiber filter paper is used as the diaphragm (GF-D), and the loading of active material is approximately 0.8-1.5 mg cm⁻¹. -2The cells were assembled into 2032 coin cells in an air environment. A NEWARE TC53 battery testing system was used for charge-discharge testing at a constant current density. The charge-discharge voltage range was 0.8–1.8V, and the charge-discharge current densities were 500, 1000, 2000, and 4000 mA / g. After charge-discharge cycles (200 cycles at 500 mA / g, 300 cycles at 1000 mA / g, 800 cycles at 2000 mA / g, and 1000 cycles at 4000 mA / g) on ​​the untreated cathode material, the capacities were 145.7 mAh / g, 128.2 mAh / g, 97.5 mAh / g, and 87.5 mAh / g, respectively. The treated cathode materials exhibited capacities of 254.1 mAh / g, 227.2 mAh / g, 147.5 mAh / g, and 114.9 mAh / g after cycling at different current densities. The zinc-ion battery λ-MnO2 cathode material with added lithium metaborate demonstrated excellent cycle performance and rate capability.

[0065] Example 5: Post-treatment of Mn3O4 cathode material with aluminum metaborate

[0066] The original manganese-based cathode material was directly synthesized by electrodeposition. Carbon cloth was used as the working electrode, 0.1 M Mn(CH3COO)2 and 0.1 M Na2S2O8 were used as the mixed electrolyte, and platinum foil was used as the counter electrode. Electrodeposition was then performed at a constant potential of 1.8 V for 20 min, yielding a loading of approximately 1.5 mg / cm³. -2Mn3O4 was further precipitated, filtered, and washed multiple times with deionized water, then vacuum dried in an oven at 110℃. A manganese-based cathode material with added aluminum metaborate was obtained via a simple solution method. 0.02g of aluminum metaborate was placed in a beaker, 50mL of deionized water was added, and the mixture was stirred for 30min. Then, 0.5g of the original manganese-based cathode material powder was immersed in the solution and stirred at room temperature for 30min. Finally, the beaker was transferred to an oven and dried at 80℃ to obtain the manganese-based cathode material with added aluminum metaborate. Transmission electron microscopy (TEM) images of the samples before and after treatment showed that the sample with added aluminum metaborate formed a Mn3O4@aluminum metaborate composite cathode material. X-ray diffraction (XRD) patterns of the powder samples before and after treatment showed that the structure and composition of the cathode material remained unchanged. XPS results of the samples before and after treatment showed the presence of a boron compound on the surface of the treated sample. XRD images of the treated sample during charge-discharge processes showed that a reversible boron-containing protective layer (including MnBx, zinc borides, etc., with x values ​​of 1 / 2, 1, 2, etc.) was formed. Electrochemical performance was tested using coin cells. The sample, conductive carbon black, and binder (polyvinylidene fluoride) were mixed at a mass ratio of 7:2:1, and an appropriate amount of solvent NMP (N-methylpyrrolidone) was added. After mixing into a slurry, the mixture was uniformly coated onto titanium foil and vacuum-dried at 110°C to obtain the electrode. A zinc sheet was used as the counter electrode, and 2 mol·L⁻¹... -1 ZnSO4 and 0.1 mol·L -1 MnSO4 is used as the electrolyte, glass fiber filter paper is used as the diaphragm (GF-D), and the loading of active material is approximately 0.8-1.5 mg cm⁻¹. -2 The cells were assembled into 2032 coin cells in an air environment. A NEWARE TC53 battery testing system was used for charge-discharge testing at a constant current density. The charge-discharge voltage range was 0.8–1.8V, and the charge-discharge current densities were 500, 1000, 2000, and 4000 mA / g. After charge-discharge cycles (200 cycles at 500 mA / g, 300 cycles at 1000 mA / g, 800 cycles at 2000 mA / g, and 1000 cycles at 4000 mA / g) on ​​the untreated cathode material, the capacities were 104.2 mAh / g, 87.4 mAh / g, 65.4 mAh / g, and 45.7 mAh / g, respectively. The treated cathode materials exhibited capacities of 145.6 mAh / g, 124.4 mAh / g, 104.7 mAh / g, and 88.5 mAh / g after cycling at different current densities. The zinc-ion battery Mn3O4 cathode material with added aluminum metaborate demonstrated excellent cycle performance and rate capability.

[0067] The foregoing description, with reference to preferred embodiments, details an exemplary embodiment of the manganese-based cathode material for zinc-ion batteries, its preparation method, and its application. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of the present invention, and various combinations can be made to the various technical features and structures proposed in the present invention without exceeding the protection scope of the present invention, which is determined by the appended claims.

Claims

1. A manganese-based cathode material for zinc-ion batteries, characterized in that, The positive electrode material is a composite material formed by adding metaboronic acid-based compounds to manganese-based oxides. The metaboronic acid-based compounds include at least one of seven: lithium metaborate, sodium metaborate, potassium metaborate, iron metaborate, magnesium metaborate, manganese metaborate, and aluminum metaborate. The manganese-based oxides include at least one of nine: α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, T-MnO2, λ-MnO2, Mn2O3, Mn3O4, and ZnMn2O4.

2. A method for preparing the manganese-based cathode material for zinc-ion batteries as described in claim 1, characterized in that, Includes the following steps: S10: Under the action of mechanical stirring, the strong oxidant and manganese salt are put into a beaker, and deionized water is added and stirred evenly to form a mixed solution of manganese salt and oxidant. S20: The above mixed solution of manganese salt and oxidant is transferred into a high-pressure reactor with a polytetrafluoroethylene liner, and then placed in an oven for heating; S30: After cooling, precipitation, filtration and washing multiple times, it is placed in an oven for vacuum drying to obtain the precursor of manganese-based cathode material; S40: Place the metaboronic acid compound in a beaker, add deionized water and stir to form a metaborate solution. Immerse the manganese-based cathode material precursor in the above metaborate solution and stir at room temperature. S50: After the beaker is placed in the oven for drying and evaporation, a manganese-based cathode material is obtained. During the process, a composite cathode material of manganese-based compound and metaboronic acid-based compound is formed.

3. The method for preparing the manganese-based cathode material for zinc-ion batteries according to claim 2, characterized in that, In step S10, the strong oxidant is a permanganate, persulfate, or peroxide.

4. The method for preparing the manganese-based cathode material for zinc-ion batteries according to claim 3, characterized in that, The strong oxidant is AMnO4, wherein A is at least one of six metal ions: Li, Na, K, Ca, Mg, and Zn; the persulfate is MS2O8, wherein M is at least one of three substances: NH4, Na, and K; and the peroxide is at least one of two substances: K2O2 and H2O2.

5. The method for preparing the manganese-based cathode material for zinc-ion batteries according to claim 2, characterized in that, In step S10, the manganese salt is at least one of manganese sulfate, manganese acetate, manganese chloride, and manganese carbonate.

6. The method for preparing the manganese-based cathode material for zinc-ion batteries according to claim 2, characterized in that, In step S30, after cooling, precipitation, filtration, and washing multiple times, the precursor of manganese-based cathode material is obtained by vacuum drying in an oven at 80-110°C.

7. The method for preparing the manganese-based cathode material for zinc-ion batteries according to claim 2, characterized in that, In step S40, the metaboronic acid compound is RBO2, wherein R is at least one of seven substances: Li, Na, K, Fe, Mg, Mn, and Al.

8. The method for preparing the manganese-based cathode material for zinc-ion batteries according to claim 2, characterized in that, In step S40, the mass ratio of the manganese-based oxide to the metaboronic acid-based compound is 1:0.01~0.

5.

9. The method for preparing the manganese-based cathode material for zinc-ion batteries according to claim 2, characterized in that, In step S50, the beaker is moved into an oven and dried at 60-80°C to obtain a manganese-based cathode material. During the process, a composite cathode material of manganese-based compound and metaboronic acid compound is formed.

10. The application of a method for preparing a manganese-based cathode material for zinc-ion batteries as described in any one of claims 2 to 9, characterized in that, The cathode material prepared by this method is used as a cathode material for zinc-ion batteries.

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