A kind of manganese-based oxide positive electrode aqueous rechargeable zinc-manganese battery with added solid acid

Abstract

The present invention provides a manganese-based oxide positive electrode aqueous rechargeable zinc-manganese battery with added solid acid, based on the proton reaction of the MnO2 positive electrode in the aqueous zinc ion battery, using the solid acid as the proton source, and providing a MnO2 / Mn 2+ The reaction provides protons, effectively regulating the pH change at the positive electrode interface, thereby reducing the generation of basic zinc sulfate as a byproduct at the positive electrode material interface during discharge. During the charging process, the solid acid radical can absorb Mn 2+ The protons released by the redeposition of MnO2 are reversibly released / absorbed by solid acid, thereby improving the reversibility of the zinc-manganese battery reaction in the battery and improving the rate performance and cycle stability of the positive electrode material. When it is used in batteries, the SO3 contained in sulfonic acid polystyrene-divinylbenzene ‑ It has the property of adsorbing metal ions and can release Mn into the electrolyte. 2+ Adsorption locks the positive electrode reaction at the positive electrode interface, shortens the reaction path, and reduces electrolyte consumption.

Description

Technical Field

[0001] The invention belongs to the technical field of new energy materials, and in particular relates to a manganese-based oxide positive electrode aqueous rechargeable zinc-manganese battery with added solid acid. Background Art

[0002] At present, lithium-ion batteries and sodium-ion batteries have been put into commercialization, but in order to cope with the energy crisis and environmental pollution problems, higher requirements are put forward for renewable energy storage devices. MnO2 has a high working voltage. 3+ / Mn 4+ It has a reversible reaction and a large theoretical capacity, and is considered to be a potential positive electrode material. MnO2 has a variety of crystal states and has a good zinc storage capacity (theoretical capacity is 308 mAh / g). Mn has multiple valence states, but there are still certain limitations. Among them, rechargeable zinc-manganese batteries currently have problems such as the generation of by-product Zn4(OH)6SO4〃xH2O (ZHS), a large range of electrolyte pH value changes, and irreversible phase change of the positive electrode, resulting in poor power density and cycle life.

[0003] Based on the limitations of MnO2 positive electrode materials, the positive electrode reaction mechanism of Zn-MnO2 batteries was explored. According to domestic and foreign research in recent years, the positive electrode reaction mechanism of Zn-MnO2 is zinc ion embedding mechanism, zinc ion proton co-embedding mechanism and proton reaction mechanism. At present, the main reaction mechanism is the proton reaction mechanism, that is, the discharge process generates MnOOH and Mn 2+ and ZHS, after charging, MnOOH, Mn 2+ Oxidation / redeposition to MnO X , and release hydrogen ions. During the reaction process, as hydrogen ions react / release during the charge and discharge process, there will be a significant change in pH at the interface between the electrolyte and the positive electrode. Zn-MnO2 batteries mainly rely on the self-regulation ability of zinc ions during the reaction process, but the self-regulation ability is limited. + The source is also single, and it will lead to the generation of a large amount of byproduct ZHS. Therefore, it is urgent to develop a manganese-based oxide positive electrode material additive to regulate the pH change of the positive electrode interface during the reaction process, so as to increase the proton source, replace part of the regulating function of zinc salts, inhibit the growth of ZHS, promote the mass transfer process of the battery, and improve the electrochemical performance of zinc-manganese batteries. Summary of the invention

[0004] The object of the present invention is to provide a manganese-based oxide positive electrode aqueous rechargeable zinc-manganese battery with added solid acid, which solves the technical problem of how to promote the battery mass transfer process, inhibits the growth of ZHS, and helps to improve the electrochemical performance of the zinc-manganese battery.

[0005] In response to the existing problems of zinc-manganese-ion batteries, such as the generation of byproduct ZHS, a large range of electrolyte pH value variations, and irreversible phase change of the positive electrode, this application has developed a new type of aqueous zinc-ion battery positive electrode material, which has shown good electrochemical performance in actual rate and cycle processes.

[0006] The present invention specifically adopts the following technical solutions.

[0007] A method for regulating the pH value at the interface of manganese-based oxide positive electrode, MnO2 / Mn 2+ The aqueous zinc-manganese battery positive electrode that provides protons for the reaction, by mechanical mixing method, one-step hydrothermal method, room temperature synthesis method, oil bath synthesis method, etc., respectively, adds different types of solid acids (including ion exchange resins, zeolites, zeolites, clays, metal oxides, metal mixed oxides, supported acids, sulfated oxides, layered transition metal oxides, metal salts, heteropoly compounds) to MnO2 as new active substances.

[0008] The manganese-based oxide positive electrode slurry with added solid acid is composed of the prepared active material, carbon black and a binder, and the ratios are (7-9): (0.5-2): (0.5-1) respectively.

[0009] At least one of the cation exchange resins is selected, wherein the sulfonic acid type polystyrene-divinylbenzene is composed of a cross-linked polystyrene matrix and a sulfonate (SO3 2- )composition.

[0010] At least one of the zeolites is selected, wherein ZSM-5 has a Si / Al ratio of 10 to infinity.

[0011] At least one of the clays is selected, wherein the main stone of kaolinite is composed of kaolinite, dickite, perlite, halloysite and other kaolinite minerals, and the most important component is kaolinite. The crystal chemical formula of kaolinite is 2SiO2〃Al2O3〃2H2O, and the theoretical chemical composition is 46.54% SiO2, 39.5% Al2O3, and 13.96% H2O.

[0012] In the solid acid-added aqueous rechargeable zinc-manganese battery positive electrode, the mass ratio of sulfonic acid polystyrene-divinylbenzene to MnO2 is 5%-50%, the mass ratio of zeolite to MnO2 is 5%-50%, and the mass ratio of kaolin to MnO2 is 5%-50%.

[0013] The electrolyte selected for the water-based rechargeable zinc-manganese battery is a mixture of zinc salt and manganese salt.

[0014] The zinc salt is preferably zinc sulfate; the concentration of the zinc salt is preferably 0-3 mol / L.

[0015] The manganese salt is preferably manganese sulfate; the concentration of the manganese salt is preferably 0.05-0.5 mol / L.

[0016] The pH value of the aqueous zinc ion battery electrolyte is 2-5.

[0017] At least one type of the aqueous rechargeable zinc-manganese battery is selected, including button batteries, soft-pack batteries, column batteries, box batteries, blade batteries, etc.

[0018] The invention provides a manganese-based oxide zinc ion battery with added solid acid and a preparation method thereof. The aqueous zinc ion battery consists of a positive electrode, a negative electrode, a diaphragm and an electrolyte prepared by the preparation method.

[0019] The negative electrode includes metallic zinc.

[0020] The mechanism of the present invention is:

[0021] The present invention adds solid acid to manganese-based oxide, and utilizes the active sites on the surface of solid acid to carry H + Compared with the single proton source of traditional aqueous zinc-manganese batteries, the pH value at the cathode interface is better regulated during the reaction process, reducing the generation of ZHS; the acid-base interaction between the acidic sites of the solid acid and the reactants causes the reaction to occur on the surface, further locking the reaction process at the cathode interface and shortening the reaction path;

[0022] Using the characteristics of different types of solid acids, sulfonic acid polystyrene-divinylbenzene belongs to cation exchange resin and is acidic; SO3 2- With H + , and releases H when the surrounding pH value is relatively low + and adsorb metal ions. On the contrary, when the surrounding pH value is relatively high, it absorbs H + And the metal ions are released, which effectively adjusts the pH value at the positive electrode interface and ensures the reversibility of the entire reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a rate performance diagram of an aqueous zinc ion battery using MnO2 with solid acid added in Example 1 and a control group.

[0024] Figure 2 This is a cycle performance diagram of an aqueous zinc ion battery using MnO2 with solid acid added in Example 1 and a control group.

[0025] Figure 3 This is a rate performance diagram of an aqueous zinc ion battery using MnO2 with solid acid added in Example 2 and a control group.

[0026] Figure 4This is a cycle performance diagram of an aqueous zinc ion battery using MnO2 with solid acid added in Example 2 and a control group.

[0027] Figure 5 This is a rate performance diagram of an aqueous zinc ion battery using MnO2 with solid acid added in Example 3 and a control group.

[0028] Figure 6 This is a cycle performance diagram of an aqueous zinc ion battery using MnO2 with solid acid added in Example 3 and a control group. DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0030] Example 1

[0031] This embodiment provides a method for preparing a manganese-based oxide positive electrode with added solid acid, and applies the method to an aqueous rechargeable zinc-manganese battery, the method comprising:

[0032] Preparation of test cell manganese-based oxide positive electrode and assembly of aqueous zinc-ion battery.

[0033] Dissolve 4.564g of ammonium persulfate and 3.3804g of manganese sulfate in 100mL of deionized water, stir well and mix together, add sulfonic acid type polystyrene-divinylbenzene and solid acid powder with a mass ratio of 5%-50% of MnO2, mix and stir for 5 minutes, pour the mixed solution into four reactors respectively, set to 140℃, and perform one-step hydrothermal synthesis for 12 hours. After synthesis, filter and wash with deionized water 3 times, put in an oven to dry, and obtain manganese-based oxide with added solid acid. Set up a comparison group, in the above synthesis process, no solid acid powder is added, and a manganese-based oxide without adding solid acid is obtained.

[0034] The prepared manganese-based oxide with added solid acid or manganese-based oxide without added solid acid: carbon black: binder = (7-9): (0.5-2): (0.5-1) were mixed, 1.1-1.3 mL of DI deionized water was added to prepare the positive electrode slurry, and then coated and dried to obtain a manganese-based oxide positive electrode with added solid acid and a control group.

[0035] The gasket is placed in the negative electrode shell, and then the stainless steel gasket, zinc sheet, double-layer diaphragm, manganese-based oxide positive electrode with added solid acid or manganese-based oxide positive electrode without added solid acid, stainless steel gasket, and positive electrode shell are placed in sequence, and electrolyte is added again during the process to wet the diaphragm, and then the battery is placed in a hydraulic button battery sealing machine for sealing to obtain an aqueous zinc ion battery.

[0036] Electrochemical performance test:

[0037] The aqueous zinc ion batteries assembled with manganese-based oxide positive electrodes with added solid acid and the control group were subjected to rate charge and discharge and constant current charge and discharge tests. The rates were set to 0.1A / g, 0.2A / g, 0.5A / g, 1A / g and 2A / g, and the constant current density was set to 1A / g.

[0038] Result analysis:

[0039] Depend on Figure 1 From the rate performance, it can be seen that the discharge specific capacity of the aqueous zinc-ion battery assembled with the manganese-based oxide positive electrode added with solid acid at current densities of 0.1A / g, 0.2A / g, 0.5A / g, 1A / g and 2A / g is significantly higher than that of the control group, indicating that the manganese-based oxide positive electrode added with solid acid can effectively improve and enhance the rate performance of aqueous rechargeable zinc-manganese batteries. Figure 2 In the experiment, at a current density of 1A / g, the initial discharge capacity of the aqueous zinc-ion battery assembled with a manganese-based oxide positive electrode with the addition of solid acid was 297.9mAh / g, and the discharge capacity after 200 cycles was 63.5mAh / g. Compared with the initial discharge capacity of the control group of 88.8mAh / g, the discharge capacity decayed to 22.7mAh / g after 200 cycles, indicating that the addition of solid acid has improved the cycle performance of aqueous zinc-manganese batteries. This is mainly because the added sulfonic acid type polystyrene-divinylbenzene carries H + , effectively reducing the generation of ZHS during the discharge process, while SO3 2- At higher pH values, H + , absorbing metal ions, locking the reaction process at the positive electrode interface, shortening the reaction path, promoting ion transmission, greatly improving the rate performance of aqueous zinc-ion batteries, and improving cycle stability.

[0040] Example 2

[0041] Preparation of test cell manganese-based oxide positive electrode and assembly of aqueous zinc-ion battery.

[0042] Dissolve 0.2 mol / L manganese sulfate and 0.2 mol / L ammonium persulfate in 150 mL of deionized water, stir well and mix together, use oil bath synthesis method, place the oil bath at 80°C for 6 hours. After the reaction is completed, filter and wash with deionized water for 3 times, and dry in an oven to obtain manganese-based oxide.

[0043] The prepared manganese-based oxide: sulfonic acid type polystyrene-divinylbenzene: carbon black: binder = 5-7.5: (1-2): (0.5-2): 1 were mixed, 1.1-1.3 mL of DI deionized water was added, and a positive electrode slurry was prepared by mechanical mixing, and then coated and dried to obtain a manganese-based oxide positive electrode with added solid acid. At the same time, manganese-based oxide, carbon black, and binder were mixed according to (7-9): (0.5-2): (0.5-1), and a manganese-based oxide positive electrode without adding solid acid was prepared according to the above method, which was set as a control group.

[0044] The gasket is placed in the negative electrode shell, and then the stainless steel gasket, zinc sheet, double-layer diaphragm, manganese-based oxide positive electrode with added solid acid or manganese-based oxide positive electrode without added solid acid, stainless steel gasket, and positive electrode shell are placed in sequence, and electrolyte is added again during the process to wet the diaphragm, and then the battery is placed in a hydraulic button battery sealing machine for sealing to obtain an aqueous zinc ion battery.

[0045] Electrochemical performance test:

[0046] The aqueous zinc ion batteries assembled with manganese-based oxide positive electrodes with added solid acid and the control group were subjected to rate charge and discharge and constant current charge and discharge tests. The rates were set to 0.1A / g, 0.2A / g, 0.5A / g, 1A / g and 2A / g, and the constant current density was set to 1A / g.

[0047] Result analysis:

[0048] Depend on Figure 3 From the rate performance, it can be seen that the discharge specific capacity of the aqueous zinc-ion battery assembled with the manganese-based oxide positive electrode added with solid acid at current densities of 0.1A / g, 0.2A / g, 0.5A / g, 1A / g and 2A / g is significantly higher than that of the control group, indicating that the manganese-based oxide positive electrode added with solid acid can effectively improve and enhance the rate performance of aqueous rechargeable zinc-manganese batteries. Figure 4 In the experiment, at a current density of 1A / g, the initial discharge capacity of the aqueous zinc-ion battery assembled with a manganese-based oxide positive electrode with the addition of solid acid was 242.2mAh / g, and the discharge capacity after 200 cycles was 184mAh / g. Compared with the initial discharge capacity of the control group of 39.1mAh / g, the discharge capacity decayed to 13.9mAh / g after 200 cycles, indicating that the addition of solid acid has improved the cycle performance of aqueous zinc-manganese batteries. This is mainly because the sulfonic acid type polystyrene-divinylbenzene is attached to the surface of manganese-based oxide through mechanical mixing, and the SO3 contained in it 2- Carry H + , effectively reducing the generation of ZHS during the reaction process, and at the same time playing a role in regulating the pH value of the surface of manganese-based oxides, further promoting the reversibility of ZHS conversion during the charge and discharge process, and obtaining excellent rate performance and cycle stability.

[0049] Example 3

[0050] Preparation of test cell manganese-based oxide positive electrode and assembly of aqueous zinc-ion battery.

[0051] 2.37g potassium permanganate was fully dissolved in 200mL deionized water, and a certain amount of ZSM-5 (the mass ratio of ZSM-5 to MnO2 was 5%-50%) was added. After stirring for 10 minutes, 0.98g sucrose dissolved in 200mL deionized water was mixed with the previous solution, and stirred at room temperature for 6 hours. Manganese-based oxides with added solid acid were prepared by room temperature synthesis. After synthesis, suction filtration was performed, and the mixture was washed with deionized water 3 times, and dried in an oven to obtain manganese-based oxides with added solid acid. A comparison group was set up. In the above synthesis process, ZSM-5 powder was not added to obtain manganese-based oxides without adding solid acid.

[0052] The prepared manganese-based oxide with added solid acid or manganese-based oxide without added solid acid: carbon black: binder = (7-9): (0.5-2): (0.5-1) were mixed, 1.1-1.3 mL of DI deionized water was added to prepare the positive electrode slurry, and then coated and dried to obtain a manganese-based oxide positive electrode with added solid acid and a control group.

[0053] The gasket is placed in the negative electrode shell, and then the stainless steel gasket, zinc sheet, double-layer diaphragm, manganese-based oxide positive electrode with added solid acid or manganese-based oxide positive electrode without added solid acid, stainless steel gasket, and positive electrode shell are placed in sequence, and electrolyte is added again during the process to wet the diaphragm, and then the battery is placed in a hydraulic button battery sealing machine for sealing to obtain an aqueous zinc ion battery.

[0054] Electrochemical performance test:

[0055] The aqueous zinc ion batteries assembled with manganese-based oxide positive electrodes with added solid acid and the control group were subjected to rate charge and discharge and constant current charge and discharge tests. The rates were set to 0.1A / g, 0.2A / g, 0.5A / g, 1A / g and 2A / g, and the constant current density was set to 1A / g.

[0056] Result analysis:

[0057] Depend on Figure 5 From the rate performance, it can be seen that the discharge specific capacity of the aqueous zinc-ion battery assembled with the manganese-based oxide positive electrode added with solid acid at current densities of 0.1A / g, 0.2A / g, 0.5A / g, 1A / g and 2A / g is significantly higher than that of the control group, indicating that the manganese-based oxide positive electrode added with solid acid can effectively improve and enhance the rate performance of aqueous rechargeable zinc-manganese batteries. Figure 6In the experiment, at a current density of 1A / g, the initial discharge capacity of the aqueous zinc-ion battery assembled with a manganese-based oxide positive electrode with the addition of solid acid was 212.6mAh / g, and the discharge capacity after 200 cycles was 164.6mAh / g. Compared with the initial discharge capacity of the control group of 125.8mAh / g, the discharge capacity decayed to 91mAh / g after 200 cycles, indicating that the addition of solid acid has improved the early cycle performance of the aqueous zinc-manganese battery. This is mainly because the added ZSM-5 structure is M x / n [(AlO2) x (SiO2) y ]〃wH2O, where M is a cation and n is the valence of the cation. The cations it carries can be exchanged with each other, and metal cations can dissociate water to produce H + , which increases H + It is worth noting that the MFI (MFI is the symbol of ZSM-5 and silica zeolite topology) structure of ZSM-5 has the highest acid strength compared with other structures, has higher proton donation performance, further adjusts the pH value of the positive electrode surface, reduces the generation of ZHS, thereby obtaining excellent rate performance and improving the discharge specific capacity during the cycle process.

[0058] Technical features not described in the present invention can be achieved through or by adopting existing technologies and will not be described in detail here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A manganese-based oxide positive electrode aqueous rechargeable zinc-manganese battery with added solid acid, comprising a positive electrode, a negative electrode, a separator and an electrolyte, characterized in that: The positive electrode includes MnO2 with several solid acids; The negative electrode comprises any one of metallic zinc, copper-zinc alloy, tin-zinc alloy, zinc-bismuth alloy, and metal zinc powder coated with a current collector, and the current collector is at least one of graphite paper, steel foil, titanium foil, and carbon cloth; The separator is placed between the positive electrode and the negative electrode during the battery assembly process, and its type is not limited to one, and the number of separator layers is not limited to one; The electrolyte is a mixture of zinc salt and manganese salt, and the pH value of the zinc ion battery electrolyte ranges from 2 to 5; The solid acid is any one of ion exchange resin, zeolite, zeolite-like, clay, metal oxide, metal mixed oxide, supported acid, sulfated oxide, layered transition metal oxide, metal salt, and heteropoly compound; The ion exchange resin is selected from sulfonic acid type polystyrene-divinylbenzene, Nafion; the zeolite is selected from ZSM-5, X-, Y-zeolite, Lingzeolite, metal aluminophosphate; the zeolite is selected from gallium silicate, cymbal silicate; the clay is selected from kaolin, montmorillonite; the metal oxide is selected from Al2O3, SiO2, Nb2O5; the metal mixed oxide is selected from SiO2-Al2O3, Nb2O5-Al2O3, SiO2-ZrO2, the supported acid is selected from H3PO4 / SiO2 (SPA), heteropoly acid / SiO2, AlCl3 / SiO2, CF3SO3H / SiO2; the sulfated oxide is selected from SO4 2- / SnO2、SO4 2- / ZrO2、SO4 2- / TiO2; the layered transition metal oxide is selected from HNbMoO6, HTaWO6, HNbWO6; the metal salt is selected from AlPO4, Nb3(PO4)5, FePO4; the heteropoly compound is selected from H3PW 12 O 40 、H4SiW 12 O 40 、H3PMo 12 O 40 ; Sulfonic acid polystyrene-divinylbenzene is composed of a cross-linked polystyrene matrix and sulfonate (SO3 2- ) and carries H + ; The ZSM-5 has two intersecting pores, both of which are formed by 10-membered rings. For zeolites with the same structure, the acid strength of the acidic OH group increases with the increase of the framework Si / Al ratio. The ZSM-5 contains at least one of SiO2 / Al2O3.

2. The aqueous rechargeable zinc-manganese battery with manganese-based oxide positive electrode and solid acid added according to claim 1, characterized in that: The positive electrode MnO2 is at least one of α-MnO2, β-MnO2, l-MnO2, d-MnO2, e-MnO2, g-MnO2, electrolytic MnO2, and amorphous MnO2.

3. The aqueous rechargeable zinc-manganese battery with manganese-based oxide positive electrode and solid acid added according to claim 1, characterized in that: The electrolyte is ZnSO4 and MnSO4, Zn(CF3SO3)2 and C2F6MnO6S2, ZnCl2 and MnCl2, Zn(NO3)2 and Mn(NO3)2, Cl2H 12 O 14 Zn and Cl2H 12 MnO 14 , any one of the combinations of Zn(CH3COO)2 and Mn(CH3COO)2.

4. The aqueous rechargeable zinc-manganese battery with manganese-based oxide positive electrode and solid acid added according to claim 3, characterized in that: In the electrolyte, the concentration of zinc salt is 0-3 mol / L, and the concentration of manganese salt is 0.05-0.5 mol / L.

5. The aqueous rechargeable zinc-manganese battery with manganese-based oxide positive electrode and added solid acid according to claim 1, characterized in that: The separator is any one of cellulose type, glass fiber type, sulfonated separator type and gel separator.

6. A method for preparing a positive electrode, based on the manganese-based oxide positive electrode aqueous rechargeable zinc-manganese battery with added solid acid as claimed in claim 2, characterized in that: The preparation method of the rechargeable zinc-manganese battery is prepared by at least one of a mechanical mixing method, a one-step hydrothermal synthesis method, a room temperature synthesis method, and an oil bath synthesis method; In the mechanical mixing method, the solid acid and MnO2 are mixed by mechanical stirring to obtain a positive electrode material with added solid acid; Alternatively, in the one-step hydrothermal synthesis method, a solid acid is added to a reaction vessel in the manganese dioxide preparation process, and the manganese dioxide with the solid acid added is prepared in situ by a one-step method; Alternatively, in the room temperature synthesis method, the manganese dioxide with added solid acid is prepared by adding the solid acid to the room temperature coprecipitation and electrodeposition manganese dioxide synthesis method; Alternatively, in the oil bath synthesis method, the manganese dioxide with added solid acid is prepared by adding the solid acid to a synthesis method that requires heating to synthesize the manganese dioxide; In the mechanical mixing method, the mass ratio of the sulfonic acid polystyrene-divinylbenzene to β-MnO2 is 5%-50%, the mass ratio of zeolite to β-MnO2 or α-MnO2 is 5%-50%, and the mass ratio of kaolin to β-MnO2 is 5%-50%.

Images