Aquatic zinc-ion battery cathode material, its preparation method and application

Abstract

This invention discloses a method for preparing and applying an aqueous zinc-ion battery cathode material, comprising the following steps: mixing a cobalt source and organic raw materials for a hydrothermal reaction, obtaining a precursor, and then treating it at high temperature to obtain the cathode material. This invention enables the synthesis of straw bundle-like Co3O4 cathode materials with micro / nano scales via a simple hydrothermal method. On the one hand, nanoparticles help increase additional active sites, shorten ion diffusion paths, and improve material conductivity. On the other hand, the microscale is beneficial for the stability of long-range electron transport networks and avoids nanostructure aggregation. Therefore, it exhibits high specific capacity and good cycle performance in electrochemical performance. In terms of production, the raw materials used are inexpensive, the equipment is simple, energy consumption is low, the production time is short, and safety is high; the overall technical solution has the advantages of green production.

Description

Technical Field

[0001] This invention belongs to the field of chemical power source technology, specifically relating to an aqueous zinc-ion battery cathode material, its preparation method, and its application. Background Technology

[0002] To ensure sustainable economic development and alleviate resource scarcity and environmental pollution, exploring green and efficient energy storage systems has become a crucial task for us in this new era. Electrochemical energy storage, with its relatively low cost, wide applicability, and high conversion efficiency, meets the needs of energy storage system development. Lithium-ion batteries, with their high energy delivery efficiency, high voltage, and long cycle life, are the most attractive and widely used in electrochemical energy storage systems. However, the high price of lithium resources—due to their limited reserves, uneven distribution, and difficult extraction—does not meet the development standard of low-cost raw materials for electrochemical energy storage systems. Furthermore, the use of toxic and flammable organic electrolytes poses a significant safety threat.

[0003] In recent years, more abundant and low-cost metal ions have emerged in the research field of rechargeable aqueous batteries. Among them, zinc has become a suitable and inexpensive anode choice for aqueous electrolytes due to its extremely high natural abundance, suitable redox potential, and high hydrogen evolution overpotential. However, although zinc ions have a small ionic radius, as a multivalent cation, they involve two-electron transfer, have a higher polarizability than lithium ions, and exhibit stronger electrostatic interactions with the crystal structure of cathode materials. Therefore, a stable structure that allows for the normal insertion and extraction of zinc ions is one of the key factors in the development of cathode materials.

[0004] Due to their abundant oxidation states, enhanced redox evenness, and reversible zinc intercalation, spinel-structured oxide materials have significant potential as cathode materials for aqueous zinc-ion batteries. Among them, Co3O4 material exhibits a high theoretical specific capacity of 896 mA hg. -1 With its good stability and reversibility, Co3O4 has the potential to become a cathode material with high capacity, high rate performance, and long cycle life. However, its low conductivity and severe volume changes result in poor charge-discharge stability and rate performance during use. Current improvement strategies mainly include morphology control, composite high-conductivity materials, and defect engineering. Among these, constructing special morphologies, such as nanoscale particle structures and overall micron-scale structures, can well adapt to volume changes during ion insertion / extraction, effectively improving electrochemical reactivity and ensuring rapid charge transport, enabling Co3O4 electrodes to effectively store zinc. Therefore, this micro / nanostructure design is very promising for developing advanced ZIBs cathodes. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing an aqueous zinc-ion battery cathode material.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing an aqueous zinc-ion battery cathode material, comprising the following steps:

[0009] Mixing transition metal salts and precipitants: Dissolve both the transition metal salt raw material and the precipitant in the same aqueous solution, stir and mix well to obtain a mixed solution of transition metal salt and precipitant;

[0010] Hydrothermal synthesis precursor: The above-mentioned mixed solution of transition metal salt precipitant is mixed and placed in a hydrothermal reactor for hydrothermal reaction. The product after the hydrothermal reaction is cooled to room temperature, washed and dried to obtain the precursor.

[0011] The cathode material is prepared by subjecting the precursor to high-temperature treatment, followed by natural cooling and grinding.

[0012] A preferred embodiment of the preparation method of the aqueous zinc-ion battery cathode material of the present invention includes: a transition metal salt being one or more of zinc salt, cadmium salt, and cobalt salt, and the precipitant being a weakly alkaline salt.

[0013] As a preferred embodiment of the preparation method of the aqueous zinc-ion battery cathode material of the present invention, it includes: in the hydrothermal reaction, the transition metal salt is a cobalt salt, and the cobalt salt is one or more of cobalt nitrate, cobalt acetate, cobalt chloride, and cobalt sulfate.

[0014] As a preferred embodiment of the preparation method of the aqueous zinc-ion battery cathode material of the present invention, it includes: in the hydrothermal reaction, the precipitant is one or more of urea, ammonium carbonate, and ammonium bicarbonate.

[0015] As a preferred embodiment of the preparation method of the aqueous zinc-ion battery cathode material of the present invention, it includes: mixing transition metal salts and precipitants, wherein the metal raw material is Co(NO3)2·6H2O and the organic raw material is CH4N2O.

[0016] As a preferred embodiment of the preparation method of the aqueous zinc-ion battery cathode material of the present invention, it includes: mixing a transition metal salt and a precipitant, wherein, by mass, the ratio of cobalt salt raw material to organic raw material is 0.5 to 2:1.

[0017] A preferred embodiment of the preparation method of the aqueous zinc-ion battery cathode material of the present invention includes: in a hydrothermal reaction, heating to 80-200°C for 2-30 hours.

[0018] A preferred embodiment of the method for preparing the aqueous zinc-ion battery cathode material according to the present invention includes: in obtaining the cathode material, the high-temperature treatment temperature is 500-800°C. During the high-temperature treatment, the heating rate is 1-20°C / min.

[0019] Another object of the present invention is to provide an application of an aqueous zinc-ion battery cathode material.

[0020] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an application of an aqueous zinc-ion battery cathode material, comprising: using the aqueous zinc-ion battery cathode material to prepare the cathode of the battery.

[0021] Beneficial effects of this invention:

[0022] (1) This invention synthesizes bundled Co3O4 cathode materials with micro- and nano-scale structures via a simple hydrothermal method. On the one hand, nanoparticles help to increase additional active sites, shorten ion diffusion paths, and improve the material's conductivity. On the other hand, the micro-scale is beneficial to the stability of long-range electron transport networks and avoids nanostructure aggregation. Therefore, the micro- and nano-scale structure, which has the combined advantages of both nano- and micro-scale, can exhibit better electrochemical zinc ion storage behavior.

[0023] (2) Cobalt-based materials have high theoretical specific capacity, but poor conductivity and cycle stability. This invention effectively improves the conductivity and thermal stability of cobalt-based materials by optimizing the hydrothermal reaction and calcination temperature and time, so that the prepared Co3O4 material has excellent cycle performance and rate performance as a positive electrode material for zinc-ion batteries.

[0024] (3) The raw materials used in this invention are inexpensive, the equipment is simple, the energy consumption is low, the time is short, and the safety is high. The Co3O4 material obtained meets the requirements of high specific capacity, low cost, and green environmental protection of zinc-ion battery cathode materials. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0026] Figure 1 The image shows the XRD pattern of the Co3O4 material obtained in Example 1 of this invention.

[0027] Figure 2 This is a SEM image of the Co3O4 material obtained in Example 1 of the present invention;

[0028] Figure 3 This is a SEM image of the Co3O4 material prepared in Comparative Example 1 of this invention.

[0029] Figure 4 This is a CV curve of the Co3O4 material obtained in Example 1 of the present invention;

[0030] Figure 5 This is a charge-discharge curve of the Co3O4 material obtained in Example 1 of the present invention;

[0031] Figure 6 The Co3O4 materials prepared in Example 1 and Comparative Example 1 of this invention were used in a process with a concentration of 0.3A g. -1 Cyclic curves at current density;

[0032] Figure 7 The Co3O4 material prepared in Example 1 of this invention was measured at 1 A g. -1 Cyclic curves at current density;

[0033] Figure 8 This is a photograph of the electrode sheet of the positive electrode material prepared in Example 1 of the present invention. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0036] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0037] Example 1

[0038] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0039] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0040] Example 2

[0041] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C for 30 h in a forced-air oven. After cooling to room temperature, the precursor was obtained by washing and drying.

[0042] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0043] Example 3

[0044] 1.746g Co(NO3)2·6H2O and 1.746g CH4N2O were dissolved in 60mL of aqueous solution. The mixture was magnetically stirred at 500rpm / min for 2h at room temperature. The solution was then transferred to a 100mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100℃ in a forced-air oven for 2h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0045] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0046] Example 4

[0047] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 200 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0048] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0049] Example 5

[0050] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 80 °C for 10 h in a forced-air oven. After cooling to room temperature, the precursor was obtained by washing and drying.

[0051] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0052] Example 6

[0053] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0054] The precursor was heated to 500℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0055] Example 7

[0056] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0057] The precursor was heated to 800℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0058] Example 8

[0059] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0060] The precursor was heated to 600℃ in air at a rate of 20℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0061] Example 9

[0062] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0063] The precursor was heated to 600℃ in air at a rate of 1℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0064] Example 10

[0065] 1.746g Co(NO3)2·6H2O and 0.873g CH4N2O were dissolved in 60mL of aqueous solution. The mixture was magnetically stirred at 500rpm / min for 2h at room temperature. The solution was then transferred to a 100mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100℃ in a forced-air oven for 10h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0066] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0067] Example 11

[0068] 0.873 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0069] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0070] Example 12

[0071] 1.746 g Co(NO3)2·6H2O and 1.746 g CH4N2O were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL para-polystyrene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0072] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0073] Example 13

[0074] 1.746 g of CoCl2·6H2O and 1.746 g of (NH4)2CO3 were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0075] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0076] Example 14

[0077] 1.746 g CoSO4·7H2O and 1.746 g NH4HCO3 were dissolved in 60 mL of aqueous solution. The mixture was magnetically stirred at 500 rpm / min for 2 h at room temperature. The solution was then transferred to a 100 mL polytetrafluoroethylene liner and placed in a hydrothermal reactor for thermal reaction. The reaction was carried out at 100 °C in a forced-air oven for 10 h. After cooling to room temperature, the precursor was obtained by washing and drying.

[0078] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0079] Comparative Example 1

[0080] 1.746 g of Co(NO3)2·6H2O was added to 60 mL of aqueous solution. The solution was magnetically stirred at 500 rpm / min at 90 °C until completely dissolved. Then, 3.0 mL of acetylacetone and 3.0 mL of hydrazine hydrate (80% N2H4H2O) were added to the solution. After a complete precipitation reaction, the precursor was obtained by washing and drying.

[0081] The precursor was heated to 600℃ in air at a rate of 5℃ / min for 2 hours, and then ground after natural cooling to obtain the Co3O4 material.

[0082] Example 15

[0083] Electrochemical performance testing:

[0084] The Co3O4 cathode material synthesized in Examples 1-14 and Comparative Example 1, Super P and polyvinylidene fluoride were uniformly mixed at a mass ratio of 70:20:10, coated on titanium foil, dried in an 80°C forced-air oven for 8 hours, and then pressed into a 14 mm diameter disc to obtain the cathode sheet. Using zinc metal as the counter electrode and 2 mol / L ZnSO4 salt solution as the electrolyte, a coin cell was assembled.

[0085] Electrochemical performance was tested using a Shenzhen Xinwei BST-5V battery tester, with a charge / discharge voltage range of 0.9V to 1.9V (vs. Zn). 2+ / Zn), and the test temperature was 25℃. The electrochemical performance of the zinc-ion batteries prepared in Examples 1-14 and Comparative Example 1 was measured using the following specific parameters: first, at 0.05A g... -1 Activation was performed at current density for 3 cycles, followed by activation at 0.3 A g. -1 The current density was cycled 100 times at 0.3 A g. -1 The discharge specific capacity obtained after 100 cycles at the current density is divided by 0.3 A g. -1 The capacity retention rate was obtained from the initial discharge specific capacity during the first cycle at the current density, and the data are shown in Table 1.

[0086] Table 1 shows the electrochemical performance of the battery cathodes prepared in Examples 1-14 and Comparative Example 1.

[0087] <![CDATA[0.3A g -1 Specific capacity (mA hg) after 100 cycles -1 )]]> Capacity retention rate (%) Example 1 218.8 54.5 Example 2 202.0 53.1 Example 3 197.8 51.2 Example 4 212.9 55.9 Example 5 206.3 53.5 Example 6 195.3 52.0 Example 7 209.2 53.7 Example 8 214.6 54.3 Example 9 208.7 53.2 Example 10 205.9 53.9 Example 11 201.9 51.8 Example 12 216.1 54.0 Example 13 211.9 52.9 Example 14 213.5 54.1 Comparative Example 1 82.3 25.4

[0088] Example 16

[0089] Electrochemical performance testing:

[0090] The Co3O4 cathode material synthesized in Example 1, Super P and polyvinylidene fluoride were uniformly mixed at a mass ratio of 70:20:10, coated on titanium foil, dried in an 80°C forced-air oven for 8 hours, and then pressed into a 14 mm diameter disc to obtain the cathode sheet. Using zinc metal as the counter electrode and 2 mol / L ZnSO4 salt solution as the electrolyte, a coin cell was assembled.

[0091] Electrochemical performance was tested using a Shenzhen Xinwei BST-5V battery tester, with a charge / discharge voltage range of 0.9V to 1.9V (vs. Zn). 2+ / Zn), the test temperature is 25℃.

[0092] The electrochemical performance of the zinc-ion battery prepared in Example 1 was measured using the following specific parameters: first, at 0.05 A g... -1 Activate at current density for 3 cycles, then at 0.05-3 A g. -1 Different current densities were selected and cyclically rotated 100 times. The data obtained are shown in Table 2.

[0093] Table 2 shows the electrochemical performance of the battery cathode prepared in Example 1 under different test conditions.

[0094] <![CDATA[Initial discharge specific capacity (mA h g -1 )]]> <![CDATA[Specific capacity (mAh g -1 ) after 100 cycles <![CDATA[0.05A g -1 ]]> 502.5 138.8 <![CDATA[0.1A g -1 ]]> 465.3 202.0 <![CDATA[0.2A g -1 ]]> 423.6 187.8 <![CDATA[0.3A g -1 ]]> 402.2 218.8 <![CDATA[0.5A g -1 ]]> 286.3 166.4 <![CDATA[0.8A g -1 ]]> 203.7 172.3 <![CDATA[1A g -1 ]]> 120.5 150.6 <![CDATA[2A g -1 ]]> 115.6 145.7 <![CDATA[3A g -1 ]]> 95.6 138.7

[0095] As shown in Table 1, considering the capacity and the capacity retention rate of the second embodiment as the main factors, and taking into account the economy of the preparation process, the difficulty of producing the equipment, and the production cost, the preferred embodiment 1 is the best embodiment of the present invention.

[0096] Table 2 shows that the Co3O4 cathode material prepared in this invention and the subsequent button cell battery exhibit good discharge performance under various current conditions, especially at 0.3 A g. -1 It exhibits good specific capacity retention after cycling under certain electrical conditions.

[0097] A comparison of the performance of button batteries prepared from the Co3O4 cathode materials obtained in Examples 1, 2, and 3 shows that both shortening and extending the heat treatment time during the preparation of the precursor will lead to a decrease in the performance of the button batteries. Therefore, the preferred heat treatment time is 10 hours.

[0098] A comparison of the performance of button batteries prepared from the Co3O4 cathode materials obtained in Examples 1, 4, and 5 shows that the best specific capacity after 100 cycles is obtained when the heating treatment temperature during the preparation of the precursor is 100°C, while the difference in capacity retention is not significant. Therefore, the preferred heating treatment temperature is 100°C.

[0099] A comparison of the performance of button batteries subsequently prepared from the Co3O4 cathode materials obtained in Examples 1, 6, and 7 shows that when the precursor is heated, both an increase and a decrease in temperature will lead to a decrease in the performance of the button batteries. Therefore, the preferred heating temperature for the precursor is 600°C.

[0100] A comparison of the performance of button batteries subsequently prepared from the Co3O4 cathode materials obtained in Examples 1, 8, and 9 shows that increasing or decreasing the heating rate during high-temperature treatment will lead to a decrease in the performance of the prepared button batteries. Therefore, the preferred heating rate during high-temperature treatment is 5°C / min.

[0101] The performance of button batteries subsequently prepared from the Co3O4 cathode materials obtained in Examples 1, 10, and 11, and their comparison, show that the cathode materials for button batteries can be prepared within a wide range of raw material proportions for Co(NO3)2·6H2O and CH4N2O. By weight, the amount of cobalt sulfate hexahydrate can be half or twice that of urea. This invention can adapt to a relatively wide range of raw material proportions, and the performance in Table 1 shows that a 1:1 mass ratio of the two raw material components is the preferred raw material weight ratio.

[0102] The performance of button batteries subsequently prepared from the Co3O4 cathode materials obtained in Examples 1 and 12, and their comparison, show that the preparation method provided by the present invention is adaptable to and capable of production in hydrothermal reactors with various types of linings.

[0103] The performance of the finished products obtained in Examples 1, 13, and 14, and their comparison, demonstrate that the present invention can use various cobalt salts as raw materials to prepare finished products. Cobalt nitrate hexahydrate exhibits the best performance when used as a raw material. According to conventional techniques in the art, in addition to cobalt salts, zinc salts and cadmium salts can also be used as sources of raw materials in this invention. CH4N2O, (NH4)2CO3, and NH4HCO3 are all suitable for use in this invention; that is, components that dissolve in water and can be electrolyzed to produce carbonate ions can be used as components in this invention.

[0104] Based on the performance of the finished products obtained in Example 1 and Comparative Example 1 and the comparison between them, it can be seen that the precursor prepared by the hydrothermal and then drying method used in Example 1 has a significant effect on improving the performance of the final product compared with other methods for preparing precursors.

[0105] Figure 7 The coin cell made of Co3O4 material prepared in Example 1 of this invention was tested at 1A g. -1 The electrochemical performance graphs at current densities show that, during the first three cycles of activation with a low current of 0.3 A / g, the initial discharge specific capacity of the Co3O4 electrode in Example 1 reaches as high as 300 mA hg. -1 After approximately 500 cycles at a high current of 1 A / g, it still exhibits a high discharge specific capacity of 175.2 mA hg. -1 This indicates that the Co3O4 electrode also exhibits excellent discharge specific capacity and cycle stability under high current.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an aqueous zinc-ion battery cathode material, characterized in that: Includes the following steps: Mixing cobalt salt and precipitant: Dissolve cobalt salt raw material and precipitant in the same aqueous solution, stir and mix well to obtain a cobalt salt precipitant mixed solution; Hydrothermal synthesis precursor: The above-mentioned mixed cobalt salt precipitant solution was placed in a hydrothermal reactor for hydrothermal reaction. The product after the hydrothermal reaction was cooled to room temperature, washed and dried to obtain the precursor. Cathode material preparation: The precursor is subjected to high temperature treatment, and after natural cooling, it is ground to obtain the cathode material; In the cobalt salt raw material and precipitant, the mass ratio of cobalt salt raw material to precipitant is 0.5~2:1; In the obtained positive electrode material, the high-temperature treatment is a high-temperature treatment at 500~800℃, and the heating rate is 1~20℃ / min; The precipitant is one or more of urea, ammonium carbonate, and ammonium bicarbonate.

2. The method for preparing the aqueous zinc-ion battery cathode material according to claim 1, characterized in that: In the hydrothermal reaction, the cobalt salt is one or more of cobalt nitrate, cobalt acetate, cobalt chloride, and cobalt sulfate.

3. The method for preparing the aqueous zinc-ion battery cathode material according to claim 1, characterized in that: In the hydrothermal reaction, the hydrothermal temperature is 80~200℃ for 2~30 hours.

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