Thin-layer metal phase tungsten disulfide positive electrode material for high-rate zinc ion battery and preparation method and application of electrode

Abstract

The invention discloses a thin-layer metal-phase tungsten disulfide positive electrode material for a high-rate zinc ion battery and an electrode preparation method and application, and relates to the technical field of zinc ion batteries. The method comprises the following steps: uniformly mixing alkali metal and tungsten disulfide, putting the mixture into a vacuum tube, and heating at 800-900 DEG C for 10-15 hours to obtain alkali metal intercalated tungsten disulfide powder; uniformly dispersing the tungsten disulfide powder of the alkali metal intercalation in a diluted potassium dichromate standard solution to obtain metal-phase tungsten disulfide powder; and dispersing the metal-phase tungsten disulfide powder into an n-butyllithium solution to obtain the thin-layer metal-phase tungsten disulfide positive electrode material. When the prepared thin-layer metal-phase tungsten disulfide is used as a positive active material, the thin-layer metal-phase tungsten disulfide, a diaphragm, a zinc ion aqueous electrolyte and zinc metal are used as a negative electrode to prepare an aqueous neutral zinc ion battery system containing the positive electrode, the diaphragm, the electrolyte and the negative electrode, and the aqueous neutral zinc ion battery system has the characteristic of high rate performance; and the material still has relatively high specific capacity and cycling stability under high current.

Description

Technical Field

[0001] The invention relates to the technical field of zinc ion batteries, and in particular to a thin-layer metal phase tungsten disulfide positive electrode material for a high-rate zinc ion battery and an electrode preparation method and application. Background Art

[0002] With the rapid development of the global economy and the continuous growth of population, natural resources are facing unprecedented depletion pressure. The excessive exploitation and use of fossil fuels have not only led to an energy crisis, but also caused serious environmental pollution problems. In this context, the development of renewable energy and energy storage technology is particularly urgent, and has become a key way to alleviate resource pressure and protect the environment. Renewable energy such as solar energy and wind energy are clean and pollution-free, but their output is intermittent and unstable due to factors such as weather and geography. Therefore, the development of energy storage technology has become the key to achieving efficient utilization of renewable energy. Lithium-ion batteries (LIBs), as the current mainstream energy storage technology, have been widely used in electric vehicles, smart phones and other fields. However, the potential safety issues of its organic electrolyte, such as thermal runaway and short circuit, seriously threaten the safety of use. Therefore, finding safer and more reliable energy storage technology has become a top priority.

[0003] In recent years, a series of aqueous batteries have been proposed and developed, including zinc-ion batteries (ZIBs), magnesium-ion batteries, aluminum-ion batteries, etc. Among the many aqueous batteries, zinc-ion batteries have attracted much attention due to their large theoretical specific capacity (820 mAh g⁻¹ and 5855 mAh cm⁻³) and low redox potential (-0.762 V vs standard hydrogen electrode). Zinc-ion batteries not only have high energy density and long cycle life, but also have abundant zinc resources and low prices, and have broad application prospects. However, due to the lack of suitable positive electrode materials, its battery cycle life and rate performance are poor, and it is still in the early stages of development. Therefore, the development of high-performance zinc-ion battery positive electrode materials has become the focus of current research.

[0004] The development of positive electrode materials for zinc-ion batteries mainly focuses on layered and tunnel structure materials, including vanadium-based compounds, manganese-based oxides, and Prussian blue analogs. However, the performance of the above mainstream positive electrode materials for zinc-ion batteries has always been unsatisfactory. This is mainly due to the slow electrochemical kinetics caused by the poor conductivity of the positive electrode material, the electrode degradation caused by the lack of structural stability, and the strong electrostatic interaction between the positive electrode and the divalent Zn²⁺ carrier, which leads to slow Zn²⁺ insertion / extraction kinetics. These problems have seriously restricted the development and application of high-rate zinc-ion batteries.

[0005] Compared with metal oxide cathodes, layered metal chalcogenides have high conductivity, good thermal stability and fast electrochemical kinetics, and therefore have attracted increasing attention as potential cathodes for high-rate zinc-ion batteries. Among layered metal chalcogenides, tungsten disulfide (WS 2 ) Because its interlayers are connected by weak van der Waals interactions, providing a fairly large lattice area that is conducive to the transport and storage of ions, and it has adjustable interlayer spacing and conductivity, it is considered to be a very promising positive electrode material for zinc-ion batteries. However, due to the poor conductivity and limited interlayer spacing of traditional semiconductor phase tungsten disulfide, satisfactory rate performance cannot be achieved. Therefore, it is of great significance to develop thin-layer metal phase tungsten disulfide materials with high conductivity, large interlayer spacing and multiple reactive active sites for high-rate zinc-ion battery positive electrodes. Summary of the invention

[0006] In view of the deficiencies in the above-mentioned background technology, the present invention mainly solves the problem that the existing semiconductor phase tungsten disulfide has poor conductivity and limited interlayer spacing, and cannot achieve satisfactory rate performance. The present invention provides a thin-layer metal phase tungsten disulfide positive electrode material for high-rate zinc ion batteries and an electrode preparation method and application. The thin-layer metal phase tungsten disulfide material of the method has a large interlayer spacing, high conductivity and multiple reactive active sites; when the thin-layer metal phase tungsten disulfide is used as the positive electrode active material, it is combined with a diaphragm, a zinc ion aqueous electrolyte, and zinc metal as the negative electrode to form an aqueous neutral zinc ion battery system comprising a positive electrode-diaphragm-electrolyte-negative electrode, which has the characteristics of high rate performance and still has a high specific capacity and cycle stability under large currents.

[0007] The first object of the present invention is to provide a method for preparing a thin layer of metal phase tungsten disulfide positive electrode material for a high-rate zinc ion battery, comprising the following steps: After the alkali metal and tungsten disulfide are evenly mixed, they are placed in a vacuum tube and heated at 800-900°C for 10-15h to obtain alkali metal intercalated tungsten disulfide powder; The alkali metal intercalated tungsten disulfide powder is uniformly dispersed in the diluted potassium dichromate standard solution, and the metal phase tungsten disulfide powder is obtained by stirring and filtering; The metal phase tungsten disulfide powder is dispersed in an n-butyl lithium solution, and after stirring and washing, a thin layer of metal phase tungsten disulfide positive electrode material is obtained.

[0008] Preferably, the molar ratio of the alkali metal to tungsten disulfide is 0.75 to 1:1.

[0009] Preferably, the concentration of the diluted potassium dichromate standard solution is 0.0009 to 0.0018 mol / L; the mass ratio of the alkali metal intercalated tungsten disulfide powder to the diluted potassium dichromate standard solution is 2 to 4:1.

[0010] Preferably, the n-butyl lithium solution is prepared by dissolving n-butyl lithium in a water solvent, and its concentration is 1.6 mol / L; The molar ratio of the metal phase tungsten disulfide powder to n-butyl lithium is 1 to 3:4.

[0011] Preferably, the alkali metal is sodium or potassium.

[0012] The second object of the present invention is to provide a thin layer of metal phase tungsten disulfide positive electrode material for high-rate zinc ion batteries.

[0013] The third object of the present invention is to provide a thin layer of metal phase tungsten disulfide positive electrode material for high-rate zinc ion batteries and its application in electrodes.

[0014] The fourth object of the present invention is to provide a thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery, wherein the raw materials include 70-80% of a thin-layer metal phase tungsten disulfide powder, 10-20% of an electronic conductive agent, 8-12% of a binder, and a current collector, and the sum of the mass fractions of the components is 100%; The electronic conductive agent includes one or more of carbon nanofibers, carbon nanotubes, conductive carbon black, and Ketjen black; The binder includes polyvinylidene fluoride and N-methylpyrrolidone; The current collector is a stainless steel sheet, a titanium sheet, a titanium mesh, a carbon cloth or a carbon paper.

[0015] A fifth object of the present invention is to provide a method for preparing a thin layer of metal phase tungsten disulfide electrode for a high-rate zinc ion battery, comprising the following steps: Weigh a thin layer of metallic phase tungsten disulfide positive electrode material, an electronic conductive agent, and a binder, add the binder into a reactor containing N-methylpyrrolidone at room temperature, and stir until completely dissolved to obtain a mixed solution; The thin layer of metal phase tungsten disulfide positive electrode material and the electronic conductive agent are mixed evenly, added into the mixed solution, and stirred to make the mixture evenly mixed to obtain an electrode slurry; The electrode slurry is coated on the current collector and vacuum dried to obtain a thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery.

[0016] The sixth object of the present invention is to provide a thin layer of metal phase tungsten disulfide electrode for high-rate zinc ion battery and its application in zinc ion battery.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a thin-layer metal phase tungsten disulfide positive electrode material for high-rate zinc ion batteries, an electrode preparation method and an application. The thin-layer metal phase tungsten disulfide positive electrode material prepared by the present invention has a layered structure and good electrical conductivity. The electrical conductivity is nearly 10 higher than that of commercial tungsten disulfide. 5 times; has a larger interlayer spacing of about 1.14 nm, which is 90% higher than commercial tungsten disulfide (interlayer spacing of 0.6 nm); its thickness is about 10 to 20 nm, with a higher specific surface area, which can provide more reactive sites. The aqueous zinc ion battery system composed of this positive electrode material and zinc sheet, electrolyte, and separator can achieve high rate performance, large capacity and good cycle performance.

[0018] The thin-layer metal phase tungsten disulfide aqueous zinc ion battery positive electrode prepared by the present invention has a high conductivity at 0.5 A g -1 The capacity is 365.89 mAh g -1 Around 5 A g -1 The high current density capacity can still be maintained at 270 mAh g -1 About 10 A g -1 The ultra-high current density capacity can reach 107.22 mAh g -1 About, and after 1000 charge and discharge cycles, the capacity retention rate reaches 71.02%. It has good rate performance, high specific capacity, long cycle period, stability and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the preparation process of the thin-layer metal phase tungsten disulfide positive electrode material obtained in Examples 1-3.

[0020] Figure 2 This is the laser Raman spectrum of the thin layer of metallic phase tungsten disulfide obtained in Example 1.

[0021] Figure 3 This is the X-ray diffraction pattern of the thin layer of metallic phase tungsten disulfide obtained in Example 1.

[0022] Figure 4 This is an atomic force microscope image of the thin layer of metallic phase tungsten disulfide obtained in Example 1.

[0023] Figure 5 This is a rate performance diagram of the thin layer metal phase tungsten disulfide aqueous zinc ion battery obtained in Example 1.

[0024] Figure 6 The thin-layer metal phase tungsten disulfide aqueous zinc ion battery obtained in Example 1 has a current density of 0.5A g -1 , 1 A g -1 , 2 A g-1 , 5A g -1 The charge and discharge curve under the following conditions; the horizontal axis is the specific capacity (SpecificCapacity), the unit is mAh g -1 ; The vertical axis is voltage (Voltage vs Zn 2+ / Zn), the unit is V.

[0025] Figure 7 The thin-layer metal phase tungsten disulfide aqueous zinc ion battery obtained in Example 1 was subjected to a current density of 10 A g -1 Specific capacity-cycle diagram under different conditions; the horizontal axis is the cycle number; the vertical axis is the specific capacity, the unit is mAh g -1 .

[0026] Figure 8 This is a scanning electron microscope image of the metallic phase tungsten disulfide obtained in Comparative Example 1.

[0027] Fig. 9 This is a rate performance diagram of the metallic phase tungsten disulfide aqueous zinc ion battery obtained in Comparative Example 1.

[0028] Fig.10 The metal phase tungsten disulfide aqueous zinc ion battery obtained in Example 1 was used at a current density of 0.2 A g -1 Specific capacity-cycle diagram under the following conditions; the horizontal axis is the cycle number (Cycle Number); the vertical axis is the capacity (Specific Capacity), the unit is mAh g -1 . DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0030] The first aspect of the present invention provides a method for preparing a thin layer of metal phase tungsten disulfide positive electrode material for a high-rate zinc ion battery, comprising the following steps: After the alkali metal and tungsten disulfide are evenly mixed, they are placed in a vacuum tube and heated at 800-900°C for 10-15h to obtain alkali metal intercalated tungsten disulfide powder; The alkali metal intercalated tungsten disulfide powder is uniformly dispersed in the diluted potassium dichromate standard solution, and the metal phase tungsten disulfide powder is obtained by stirring and filtering; The metal phase tungsten disulfide powder is dispersed in an n-butyl lithium solution, and after stirring and washing, a thin layer of metal phase tungsten disulfide positive electrode material is obtained.

[0031] The thin-layer metal phase tungsten disulfide material prepared by the present invention has a large interlayer spacing, high conductivity and multiple reaction active sites; when the thin-layer metal phase tungsten disulfide is used as a positive electrode active material, it is combined with a diaphragm, a zinc ion aqueous electrolyte and zinc metal as a negative electrode to form an aqueous neutral zinc ion battery system comprising a positive electrode-diaphragm-electrolyte-negative electrode, which has the characteristics of high rate performance and still has high specific capacity and cycle stability under large current.

[0032] Wherein, the molar ratio of the alkali metal to tungsten disulfide is 0.75~1:1.

[0033] The concentration of the diluted potassium dichromate standard solution is 0.0009 to 0.0018 mol / L; the mass ratio of the alkali metal intercalated tungsten disulfide powder to the diluted potassium dichromate standard solution is 2 to 4:1.

[0034] The n-butyl lithium solution is prepared by dissolving n-butyl lithium in a water solvent, and its concentration is 1.6 mol / L; the molar ratio of the metal phase tungsten disulfide powder to n-butyl lithium is 1 to 3:4.

[0035] The alkali metal is sodium or potassium.

[0036] Exemplarily, a method for preparing a thin layer of metal phase tungsten disulfide positive electrode material for a high-rate zinc ion battery comprises the following steps: Step 1: Mix the alkali metal and tungsten disulfide evenly and seal them in a vacuum glass tube.

[0037] Step 2, placing the glass tube in step 1 in a muffle furnace for heating; and obtaining alkali metal intercalated tungsten disulfide powder after natural cooling. The heating temperature in step 2 is 800°C to 900°C, the heating time is 10 to 15h, and the heating rate is 12.5°C to 14°C / min.

[0038] Step 3, dispersing the powder in step 2 into a diluted potassium dichromate standard solution, stirring, filtering, and drying; obtaining a metal phase tungsten disulfide powder.

[0039] Step 4, dispersing the powder in step 3 into an n-butyl lithium solution and stirring, adding ultrapure water for ultrasonication after drying, centrifuging and drying; obtaining a thin layer of metal phase tungsten disulfide positive electrode material.

[0040] The stirring speed in step 3 and step 4 is 600 ~ 1000 r / min, wherein the stirring time in step 3 is 2 ~ 4 h, and the stirring time in step 4 is 20 ~ 24 h.

[0041] A second aspect of the present invention provides a thin-layer metal phase tungsten disulfide positive electrode material for a high-rate zinc ion battery.

[0042] A third aspect of the present invention provides an application of a thin layer of metal phase tungsten disulfide positive electrode material for a high-rate zinc ion battery in an electrode.

[0043] The fourth aspect of the present invention provides a thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery, wherein the raw materials include 70-80% of a thin-layer metal phase tungsten disulfide powder, 10-20% of an electronic conductive agent, 8-12% of a binder, and a current collector, and the sum of the mass fractions of the components is 100%; The electronic conductive agent includes one or more of carbon nanofibers, carbon nanotubes, conductive carbon black, and Ketjen black; The binder includes polyvinylidene fluoride and N-methylpyrrolidone; The current collector is a stainless steel sheet, a titanium sheet, a titanium mesh, a carbon cloth or a carbon paper.

[0044] The mass fraction of the thin layer metal phase tungsten disulfide powder can be 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79% or 80%, etc., the mass fraction of the electronic conductive agent can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., and the mass fraction of the binder can be 8%, 9%, 10%, 11% or 12%, etc., but are not limited to the listed values, and other unlisted values ​​within the above numerical ranges are also applicable.

[0045] The binder of the present invention comprises 28-33% polyvinylidene fluoride and 67-72% N-methylpyrrolidone by mass fraction. The mass fraction of the polyvinylidene fluoride can be 28%, 29%, 30%, 31%, 32% or 33%, etc., and the mass fraction of the N-methylpyrrolidone can be 67%, 68%, 69%, 70%, 71% or 72%, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical ranges are also applicable.

[0046] A fifth aspect of the present invention provides a method for preparing a thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery, comprising the following steps: Weigh a thin layer of metallic phase tungsten disulfide positive electrode material, an electronic conductive agent, and a binder, add the binder into a reactor containing N-methylpyrrolidone at room temperature, and stir until completely dissolved to obtain a mixed solution; The thin layer of metal phase tungsten disulfide positive electrode material and the electronic conductive agent are mixed evenly, added into the mixed solution, and stirred to make the mixture evenly mixed to obtain an electrode slurry; The electrode slurry is coated on the current collector and vacuum dried to obtain a thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery.

[0047] Exemplarily, a method for preparing a thin-layer metal phase tungsten disulfide electrode for high-rate zinc ions comprises the following steps: Step S1, weighing a thin layer of metal phase tungsten disulfide positive electrode material, a conductive agent, and a binder, adding the binder into a reactor containing N-methylpyrrolidone at room temperature, and stirring until completely dissolved to obtain a mixed solution.

[0048] Step S2, mixing the thin layer of metal phase tungsten disulfide positive electrode material and the conductive agent evenly, adding them to the mixed solution described in step S1, stirring to make them evenly mixed, and obtaining electrode slurry; Step S3, coating the electrode slurry on carbon paper, and vacuum drying to obtain a thin layer of metal phase tungsten disulfide electrode for high-rate zinc ion batteries.

[0049] A sixth aspect of the present invention provides an application of a thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery in a zinc ion battery.

[0050] It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used are all commercially available unless otherwise specified.

[0051] Example 1 This embodiment provides a preparation method and application of a thin-layer metal phase tungsten disulfide positive electrode material and electrode for a high-rate zinc ion battery, see Figure 1 As shown, the following steps are included: (1) Preparation of thin-layer metal phase tungsten disulfide positive electrode material: 0.2 g of metallic potassium and 1.057 g of tungsten disulfide were weighed in a glove box, mixed evenly and sealed in a quartz glass tube. The above glass tube was placed in a muffle furnace and heated at 850°C for 15 h; cooled naturally to room temperature to obtain tungsten disulfide powder intercalated with metallic potassium. The above powder was dispersed in 100 mL of 0.0009 mol / L potassium dichromate solvent, stirred continuously for 3 h, filtered and washed with ultrapure water, and freeze-dried for 24 h to obtain metallic phase tungsten disulfide. In a glove box, the above metallic phase tungsten disulfide powder was dispersed in 2 mL of 1.6 mol / L n-butyl lithium solution, stirred continuously for 20 h, dried, added 20 mL of ultrapure water, and ultrasonicated in an ice water bath for 1 h. The obtained solution was centrifuged at 10,000 rpm for 30 min, and the black liquid was collected and freeze-dried to obtain a thin-layer metal phase tungsten disulfide powder.

[0052] (2) Preparation of thin-layer metallic tungsten disulfide electrode: 30 wt% of polyvinylidene fluoride powder and 70 wt% of N-methylpyrrolidone solution are stirred until the powder is completely dissolved to obtain a binder; 80 wt% of thin-layer metallic tungsten disulfide powder, 10 wt% of carbon nanofiber powder and 10 wt% of the binder are stirred evenly to obtain electrode ink; the electrode ink is coated on a titanium foil and dried in a vacuum oven at 60 °C for 10 h to obtain a thin-layer metallic tungsten disulfide electrode for high-rate zinc-ion batteries.

[0053] (3) Application of thin-layer metallic tungsten disulfide electrode: The positive electrode of zinc ion secondary battery is prepared by using the above-mentioned thin-layer metallic tungsten disulfide electrode. The negative electrode material is a zinc negative electrode made of metal zinc sheet. The electrolyte is 2 mol / L zinc sulfate as solute and water as solvent. The diaphragm is a glass fiber diaphragm and the stainless steel shell is used as the outer shell to assemble into a CR2025 button battery.

[0054] The intermediate samples and final samples prepared in Example 1 are actually tested below.

[0055] Figure 2 This is the laser Raman spectrum of the prepared thin layer of metallic phase tungsten disulfide. According to the position of the Raman peak, it can be concluded that the prepared thin layer of metallic phase tungsten disulfide is a pure metallic phase and does not contain other phases (such as semiconductor phase). This can ensure that it has excellent electrical conductivity. High electrical conductivity is conducive to the rapid migration of zinc ions.

[0056] Figure 3 This is the X-ray diffraction pattern of the prepared thin layer of metallic phase tungsten disulfide. It can be seen that the prepared thin layer of metallic phase tungsten disulfide has good crystallinity, and according to the Bragg equation for the 002 crystal plane, it can be obtained that its interlayer spacing is about 1.14 nm. The larger interlayer spacing is conducive to the deintercalation of a large number of zinc ions.

[0057] Figure 4 From the atomic force micrograph of the prepared thin layer of metallic phase tungsten disulfide, it can be seen that the thickness of the prepared thin layer of metallic phase tungsten disulfide is about 15.96 nm. Thinner nanosheets are beneficial in exposing more reactive sites and adsorbing more zinc ions to participate in the reaction.

[0058] Figure 5 The obtained thin-layer metallic phase tungsten disulfide aqueous zinc ion battery is -1 , 1 A g -1 , 2 A g -1 , 5A g -1 Four rate performance diagrams at different densities. It can be found that at 0.5 A g -1 At a low current density of 1.34 W, the discharge capacity of the battery is as high as 365.89 mAh g -1 , and at 5 A g-1 At a high current density of 270 mAh g -1 High capacity. This shows that the thin-layer metal phase tungsten disulfide electrode not only has high capacity, but also has high rate performance.

[0059] Figure 6 The obtained thin-layer metallic phase tungsten disulfide aqueous zinc ion battery has a high conductivity at 0.5 A g -1 , 1 A g -1 , 2 A g -1 , 5A g -1 The charge and discharge curves at four different densities show that when the current density increases from 0.5 A g −1 Increased 10 times to 5 A g −1 The charge-discharge curves always maintain a similar shape when the charge is charged. This indicates that the thin-layer metallic phase tungsten disulfide electrode has good redox reaction reversibility and fast charge storage kinetics.

[0060] Figure 7 The obtained thin-layer metallic phase tungsten disulfide aqueous zinc ion battery has a current density of 10 A g -1 The specific capacity-cycle diagram under the conditions shows that at 10 A g -1 At an ultra-high current density, its capacity can still reach 107.22 mAh g -1 , and after 1000 charge and discharge cycles, the capacity retention rate reached 71.02%, indicating that the thin-layer metal phase tungsten disulfide electrode has good cycle performance.

[0061] The above data illustrate that the thin-layer metal phase tungsten disulfide electrode prepared by the present invention has high capacity and high rate performance when used as the positive electrode of zinc ion batteries, and also has good cycle stability.

[0062] Example 2 This embodiment provides a preparation method and application of a thin-layer metal phase tungsten disulfide positive electrode material and electrode for a high-rate zinc ion battery, see Figure 1 As shown, the following steps are included: (1) Preparation of thin-layer metal phase tungsten disulfide positive electrode material: 0.4 g of potassium metal and 2.114 g of tungsten disulfide were weighed in a glove box, mixed evenly and sealed in a quartz glass tube. The glass tube was placed in a muffle furnace and heated at 800 °C for 12 h; cooled naturally to room temperature to obtain tungsten disulfide powder intercalated with potassium metal. The powder obtained above was dispersed in 100 mL of 0.0012 mol / L potassium dichromate solvent, stirred continuously for 4 h, filtered and washed with ultrapure water, and freeze-dried for 24 h to obtain metal phase tungsten disulfide. In a glove box, the metal phase tungsten disulfide powder obtained above was dispersed in 3 mL of 1.6 mol / L n-butyl lithium solution, stirred continuously for 24 h, dried, added 20 mL of ultrapure water, and ultrasonicated in an ice water bath for 1 h. The obtained solution was centrifuged at 10,000 rpm for 30 min, and the black liquid was collected and freeze-dried to obtain a thin layer of metal phase tungsten disulfide powder.

[0063] (2) Preparation of thin-layer metallic tungsten disulfide electrode: 28wt% of polyvinylidene fluoride powder and 72wt% of N-methylpyrrolidone solution are stirred until the powder is completely dissolved to obtain a binder; 70wt% of thin-layer metallic tungsten disulfide powder, 20wt% of carbon nanofiber powder and 10wt% of the binder are stirred evenly to obtain electrode ink; the electrode ink is coated on carbon paper and dried in a vacuum oven at 60°C for 10 h to obtain a thin-layer metallic tungsten disulfide electrode for high-rate zinc-ion batteries.

[0064] (3) Application of thin-layer metallic tungsten disulfide electrode: The positive electrode of zinc ion secondary battery is prepared by using the above-mentioned thin-layer metallic tungsten disulfide electrode. The negative electrode material is a zinc negative electrode made of metal zinc sheet. The electrolyte is 2 mol / L zinc sulfate as solute and water as solvent. The diaphragm is a glass fiber diaphragm and the stainless steel shell is used as the outer shell to assemble into a CR2025 button battery.

[0065] Example 3 This embodiment provides a preparation method and application of a thin-layer metal phase tungsten disulfide positive electrode material and electrode for a high-rate zinc ion battery, see Figure 1 As shown, the following steps are included: (1) Preparation of thin-layer metal-phase tungsten disulfide cathode material: Weigh 0.2 g of metallic sodium and 1.057 g of tungsten disulfide in a glove box, mix them evenly and seal them in a quartz glass tube. Place the above glass tube in a muffle furnace and heat it at 900 °C for 12 h; naturally cool it to room temperature to obtain tungsten disulfide powder intercalated with metallic sodium. Disperse the powder obtained above into 100 mL of 0.0018 mol / L potassium dichromate solvent, stir continuously for 2 h, filter and wash it with ultrapure water, and then freeze-dry it for 24 h to obtain metal-phase tungsten disulfide. Disperse the obtained metal-phase tungsten disulfide powder into 2 mL of 1.6 mol / L n-butyllithium solution in a glove box, stir continuously for 24 h, add 20 mL of ultrapure water after drying, and ultrasonicate it in an ice-water bath for 1 h. Centrifuge the obtained solution at 10000 rpm for 30 min, collect the black liquid and freeze-dry it to obtain thin-layer metal-phase tungsten disulfide powder.

[0066] (2) Preparation of thin-layer metal-phase tungsten disulfide electrode: Mix 32 wt% of polyvinylidene fluoride powder and 68 wt% of N-methylpyrrolidone solution, and stir until the powder is completely dissolved to obtain a binder; mix 70 wt% of thin-layer metal-phase tungsten disulfide powder, 10 wt% of carbon nanofiber powder, 10 wt% of conductive carbon black powder and 10 wt% of binder, and stir evenly to obtain electrode ink; coat the electrode ink on a titanium foil and place it in a vacuum oven at 60 °C for drying for 10 h to obtain a thin-layer metal-phase tungsten disulfide electrode for high-rate zinc-ion batteries.

[0067] (3) Application of thin-layer metal-phase tungsten disulfide electrode: Use the above thin-layer metal-phase tungsten disulfide electrode to prepare the cathode of a zinc-ion secondary battery. The anode material is a zinc anode made of a zinc sheet. The electrolyte uses 2 mol / L zinc sulfate as the solute and water as the solvent, the separator is a glass fiber separator, and the stainless steel shell is used as the outer shell to assemble a CR2025 button battery.

[0068] Comparative Example 1 Compared with Example 1, n-butyllithium solution was not used to treat metal-phase tungsten disulfide; (1) Preparation of metal-phase tungsten disulfide cathode material: Weigh 0.2 g of metallic potassium and 1.057 g of tungsten disulfide in a glove box, mix them evenly and seal them in a quartz glass tube. Place the above glass tube in a muffle furnace and heat it at 850 °C for 15 h; naturally cool it to room temperature to obtain tungsten disulfide powder intercalated with metallic potassium. Disperse the powder obtained above into 100 mL of 0.0009 mol / L potassium dichromate solvent, stir continuously for 3 h, filter and wash it with ultrapure water, and then freeze-dry it for 24 h to obtain metal-phase tungsten disulfide.

[0069] (2) Preparation of metallic tungsten disulfide electrode: 30 wt% of polyvinylidene fluoride powder and 70 wt% of N-methylpyrrolidone solution are stirred until the powder is completely dissolved to obtain a binder; 80 wt% of metallic tungsten disulfide powder, 10 wt% of carbon nanofiber powder and 10 wt% of the binder are stirred evenly to obtain electrode ink; the electrode ink is coated on a titanium foil and dried in a vacuum oven at 60 °C for 10 h to obtain a metallic tungsten disulfide electrode for zinc ion batteries.

[0070] (3) Application of metallic tungsten disulfide electrode: The positive electrode of zinc ion secondary battery is prepared by using the metallic tungsten disulfide electrode. The negative electrode material is a zinc negative electrode made of metal zinc sheet. The electrolyte is 2 mol / L zinc sulfate as solute and water as solvent. The diaphragm is a glass fiber diaphragm and the stainless steel shell is used as the outer shell to assemble into a CR2025 button battery.

[0071] The following is the actual test of the intermediate sample and the final sample prepared in Example 1.

[0072] Figure 8 From the scanning electron microscope image of the prepared metal phase tungsten disulfide, it can be seen that the prepared metal phase tungsten disulfide is blocky and cannot expose more reactive sites for zinc ions to participate in the reaction.

[0073] Fig. 9 The obtained metallic phase tungsten disulfide aqueous zinc ion battery is 0.2 A g -1 , 0.5 A g -1 , 1 A g -1 , 2A g -1 , 5A g -1 The rate performance diagrams at five different densities. It can be found that at 0.2 A g -1 At a low current density of 1.34 W, the discharge capacity of the battery is only 109.7 mAh g -1 , and when the current density increases to 5 A g -1 When the discharge capacity drops to 78.2 mAh g -1 This indicates that the capacity and rate performance of the metal phase tungsten disulfide electrode are relatively weak.

[0074] Fig.10 The obtained metallic phase tungsten disulfide aqueous zinc ion battery has a current density of 0.2 A g -1 The specific capacity-cycle diagram under the conditions shows that at 0.2 A g -1 After 200 charge and discharge cycles at a current density of , the capacity retention rate is only 63.1%. The cycling performance is relatively weak.

[0075] In summary, compared with the examples, the metal phase tungsten disulfide that has not been treated with n-butyl has the problems of thick material thickness that cannot provide sufficient active sites for electrochemical energy storage reactions and insufficient interlayer spacing, which leads to relatively weak performance in battery capacity and cycle stability.

[0076] The present invention describes preferred embodiments and their effects. However, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0077] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a thin layer of metal phase tungsten disulfide positive electrode material for a high-rate zinc ion battery, characterized in that: The following steps are involved: After the alkali metal and tungsten disulfide are evenly mixed, they are placed in a vacuum tube and heated at 800-900°C for 10-15h to obtain alkali metal intercalated tungsten disulfide powder; The alkali metal intercalated tungsten disulfide powder is uniformly dispersed in the diluted potassium dichromate standard solution, and the metal phase tungsten disulfide powder is obtained by stirring and filtering; The metal phase tungsten disulfide powder is dispersed in an n-butyl lithium solution, and after stirring and washing, a thin layer of metal phase tungsten disulfide positive electrode material is obtained.

2. The method for preparing a thin layer of metal phase tungsten disulfide positive electrode material for a high rate zinc ion battery according to claim 1, wherein: The molar ratio of the alkali metal to tungsten disulfide is 0.75 to 1:

1.

3. The method for preparing a thin layer of metal phase tungsten disulfide positive electrode material for a high rate zinc ion battery according to claim 1, characterized in that: The concentration of the diluted potassium dichromate standard solution is 0.0009 to 0.0018 mol / L; the mass ratio of the alkali metal intercalated tungsten disulfide powder to the diluted potassium dichromate standard solution is 2 to 4:

1.

4. The method for preparing a thin layer of metal phase tungsten disulfide positive electrode material for a high rate zinc ion battery according to claim 1, characterized in that: The n-butyl lithium solution is prepared by dissolving n-butyl lithium in a water solvent, and its concentration is 1.6 mol / L; The molar ratio of the metal phase tungsten disulfide powder to n-butyl lithium is 1 to 3:

4.

5. The method for preparing a thin layer of metal phase tungsten disulfide positive electrode material for a high rate zinc ion battery according to claim 1, characterized in that: The alkali metal is sodium or potassium.

6. A thin layer of metallic phase tungsten disulfide positive electrode material for a high-rate zinc ion battery prepared by the method according to any one of claims 1 to 5.

7. Use of the thin-layer metal phase tungsten disulfide positive electrode material for high-rate zinc ion batteries according to claim 6 in electrodes.

8. A thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery, characterized in that: The raw materials include 70-80% of the thin-layer metal phase tungsten disulfide powder as described in claim 6, 10-20% of the electronic conductive agent, 8-12% of the binder, and the current collector, and the sum of the mass fractions of the components is 100%; The electronic conductive agent includes one or more of carbon nanofibers, carbon nanotubes, conductive carbon black, and Ketjen black; The binder includes polyvinylidene fluoride and N-methylpyrrolidone; The current collector is a stainless steel sheet, a titanium sheet, a titanium mesh, a carbon cloth or a carbon paper.

9. A method for preparing a thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery according to claim 8, characterized in that: The following steps are involved: Weigh a thin layer of metallic phase tungsten disulfide positive electrode material, an electronic conductive agent, and a binder, add the binder into a reactor containing N-methylpyrrolidone at room temperature, and stir until completely dissolved to obtain a mixed solution; The thin layer of metal phase tungsten disulfide positive electrode material and the electronic conductive agent are mixed evenly, added into the mixed solution, and stirred to make the mixture evenly mixed to obtain an electrode slurry; The electrode slurry is coated on the current collector and vacuum dried to obtain a thin-layer metal phase tungsten disulfide electrode for a high-rate zinc ion battery.

10. Use of the thin-layer metal phase tungsten disulfide electrode for high-rate zinc ion battery according to claim 8 in a zinc ion battery.

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