Tellurium-doped sulfurized polyacrylonitrile potassium storage negative electrode material and potassium ion total battery

Abstract

The invention discloses a tellurium-doped sulfurized polyacrylonitrile potassium storage negative electrode material and a potassium ion total battery, and belongs to the field of potassium ion batteries. In order to solve the technical problems of low sulfur utilization rate and poor rate capability when sulfurized polyacrylonitrile is used as a potassium storage negative electrode material, the tellurium-doped sulfurized polyacrylonitrile (Te-SPAN) material with high performance is synthesized in a tellurium doping manner. In the tellurium-doped sulfurized polyacrylonitrile (Te-SPAN), the content of tellurium is lower than 5%, the content of sulfur is 33%-39%, and the content of carbon is 59%-62%. When the Te-SPAN is used as a potassium storage negative electrode material, the Te-SPAN shows high potassium storage capacity, excellent rate capability and cycling stability. In addition, the potassium ion total battery assembled based on the composite negative electrode and the low-defect manganese potassium hexacyanoferrate positive electrode also shows very excellent electrochemical performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of potassium ion batteries, and particularly relates to a method for preparing a tellurium-doped polyacrylonitrile sulfide potassium storage negative electrode material and a potassium ion full battery. BACKGROUND

[0002] Potassium ion batteries are considered as a very promising low-cost electrochemical energy storage system, and are expected to become one of the supplementary electrochemical energy storage systems of lithium ion batteries, and are applied to large-scale energy storage scenarios with low energy density requirements but low cost requirements. In order to meet the requirements of high performance and low cost of energy storage batteries in large-scale energy storage scenarios, it is crucial to develop high-performance and low-cost potassium storage electrode materials to promote the development of potassium ion batteries. At present, great progress has been made in the research on potassium ion batteries. In terms of positive electrode materials, a high-performance low-defect potassium manganese hexacyanoferrate positive electrode material has been developed, which has an average discharge voltage as high as 3.94V (vs. K+ / K) when used as a potassium storage positive electrode material, and a mass energy density of 609Wh kg-1, and has very excellent cycle stability. The above advantages make the low-defect potassium manganese hexacyanoferrate material expected to become a positive electrode material for future practical potassium ion full batteries. + -1 However, in terms of negative electrode materials, the lack of high-performance and low-cost potassium storage negative electrode materials is one of the main factors restricting the practical application of potassium ion batteries. Graphite is a widely used potassium storage negative electrode material, but it has problems such as slow kinetics, low capacity, and poor cycle stability, and is difficult to be used in practical potassium ion full batteries. Sulfurized polyacrylonitrile (SPAN) material is also a kind of relatively potential potassium storage negative electrode material, which has low cost, easy preparation, high potassium storage capacity and good cycle stability. However, this kind of material still faces the problems of low sulfur utilization rate and low capacity at high rate, which also limits the potential of sulfurized polyacrylonitrile (SPAN) material as a potassium storage negative electrode material. Further improving the electrochemical potassium storage performance of sulfurized polyacrylonitrile material is expected to enhance its potential as a potassium storage negative electrode material. It has been reported that the electrochemical performance of lithium and sodium storage of sulfurized polyacrylonitrile (SPAN) material can be effectively improved by tellurium doping. In the literature reports, the synthesis of this kind of material is complicated, and it is generally used as a lithium and sodium storage positive electrode material. Therefore, it is of great significance to simplify the preparation method of tellurium-doped sulfurized polyacrylonitrile and obtain a high-performance potassium storage negative electrode material, and to assemble a competitive potassium ion full battery based on it.

[0003] However, in terms of negative electrode materials, the lack of high-performance and low-cost potassium storage negative electrode materials is one of the main factors restricting the practical application of potassium ion batteries. Graphite is a widely used potassium storage negative electrode material, but it has problems such as slow kinetics, low capacity, and poor cycle stability, and is difficult to be used in practical potassium ion full batteries. Sulfurized polyacrylonitrile (SPAN) material is also a kind of relatively potential potassium storage negative electrode material, which has low cost, easy preparation, high potassium storage capacity and good cycle stability. However, this kind of material still faces the problems of low sulfur utilization rate and low capacity at high rate, which also limits the potential of sulfurized polyacrylonitrile (SPAN) material as a potassium storage negative electrode material. Further improving the electrochemical potassium storage performance of sulfurized polyacrylonitrile material is expected to enhance its potential as a potassium storage negative electrode material. It has been reported that the electrochemical performance of lithium and sodium storage of sulfurized polyacrylonitrile (SPAN) material can be effectively improved by tellurium doping. In the literature reports, the synthesis of this kind of material is complicated, and it is generally used as a lithium and sodium storage positive electrode material. Therefore, it is of great significance to simplify the preparation method of tellurium-doped sulfurized polyacrylonitrile and obtain a high-performance potassium storage negative electrode material, and to assemble a competitive potassium ion full battery based on it. SUMMARY

[0004] ​In order to solve the problems of low sulfur utilization rate and low capacity at high rate of the current sulfidized polyacrylonitrile potassium storage negative material, a synthesis method of tellurium doped sulfidized polyacrylonitrile is adopted, so that the potassium storage performance of the material is improved, and on this basis, a high-performance and low-cost potassium ion full battery is assembled.

[0005] The application provides a high-performance tellurium doped sulfidized polyacrylonitrile potassium storage negative material and a potassium ion full battery.

[0006] Step one: using tellurium, sulfur and polyacrylonitrile as raw materials, a tellurium doped sulfidized polyacrylonitrile material is prepared through thermal polymerization.

[0007] Step two: using the tellurium doped sulfidized polyacrylonitrile material as a negative material and low-defect manganese potassium hexacyanoferrate as a positive material, a potassium ion full battery is assembled.

[0008] Preferably, in step one, the mass ratio of tellurium to sulfur is 0-0.02.

[0009] Preferably, in step one, the mass ratio of sulfur to polyacrylonitrile is 1:1-1:3.

[0010] Preferably, in step one, the heat treatment temperature is 350-450 DEG C.

[0011] Preferably, in step one, the reaction atmosphere is nitrogen or argon.

[0012] Preferably, in step two, the loading amount of the tellurium doped sulfidized polyacrylonitrile as the negative material is 1-5 mg cm -2 .

[0013] Preferably, in step two, the loading amount of the low-defect manganese potassium hexacyanoferrate as the positive material is 4-18 mg cm -2 .

[0014] Preferably, in step two, the capacity ratio of the positive electrode to the negative electrode is 0.9:1-0.95:1.

[0015] Preferably, in step two, the working voltage of the potassium ion full battery is 0.5-4.2 V.

[0016] Preferably, in step two, the potassium ion full battery includes a button type battery and a soft package battery.

[0017] The application has the following beneficial effects:

[0018] 1) In the preparation process of the application, simple and easily available raw materials with low cost are used, the reaction is carried out at 350-450 DEG C, the whole process is simple, and the energy consumption is low.

[0019] 2) When the tellurium-doped sulfurized polyacrylonitrile material prepared by this invention is used as a potassium storage anode material, it has high sulfur utilization, good rate performance and cycle stability.

[0020] 3) The potassium-ion full battery prepared by this invention exhibits excellent charge and discharge performance. Attached Figure Description

[0021] Figure 1 This is the X-ray diffraction pattern of the tellurium-doped sulfurized polyacrylonitrile material of Example 1 of the present invention;

[0022] Figure 2 This is a morphology characterization diagram of the tellurium-doped sulfurized polyacrylonitrile material of Example 1 of the present invention;

[0023] Figure 3 This is a rate performance diagram of tellurium-doped sulfided polyacrylonitrile in a potassium metal half-cell according to Example 1 of the present invention.

[0024] Figure 4 This is a charge-discharge curve of the potassium-ion full battery of Example 1 of the present invention at a rate of 0.1C;

[0025] Figure 5 This is a cycle stability diagram of the potassium-ion full battery of Example 1 of the present invention at a 3C rate. Detailed Implementation

[0026] Unless otherwise specified, all technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] Throughout this invention, when describing certain methods as including or having certain specific steps, it means that the methods of this invention may consist essentially of or be composed of these referenced steps.

[0028] Unless otherwise defined, the term "including" should generally be understood as open-ended and non-restrictive.

[0029] Unless otherwise stated, all numerical values ​​representing quantities, percentages, or proportions in this invention, or other numerical values ​​used in this specification or claims, should be understood as approximate. Unless otherwise stated, numerical values ​​appearing in the specification are estimates and depend on the nature of the information being sought. At a minimum, each numerical parameter should be interpreted as obtained by applying ordinary rounding based on the stated significant value.

[0030] Unless otherwise defined, the term "approximately" is used before a numerical value, and this teaching includes the value itself. Unless otherwise defined, the term "approximately" as used herein includes a difference of plus or minus 10% of the numerical value.

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described below are intended to facilitate the understanding of the present invention and are not intended to limit it in any way.

[0032] Example 1

[0033] A tellurium-doped sulfide polyacrylonitrile potassium storage anode material and a potassium-ion full cell, comprising the following steps:

[0034] Step 1: Using elemental tellurium, elemental sulfur, and polyacrylonitrile as raw materials, tellurium-doped sulfurized polyacrylonitrile materials are prepared by thermal polymerization.

[0035] 0.01 g of elemental tellurium, 1 g of elemental sulfur, and 3 g of sulfurized polyacrylonitrile were weighed and mixed thoroughly. The mixture was then heat-treated at 350 °C for 5 hours under an argon atmosphere. After cooling, tellurium-doped sulfurized polyacrylonitrile material was obtained. The crystal structure, morphology, and chemical composition of the prepared sample were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and elemental analysis. A potassium metal half-cell was assembled using the tellurium-doped sulfurized polyacrylonitrile material as the positive electrode and potassium metal as the negative electrode. The performance of this material in the range of 0.1–2.5 V (vs. K) was tested. + Electrochemical performance in the / K voltage range.

[0036] Step 2: Assemble a potassium-ion full cell using tellurium-doped sulfide polyacrylonitrile as the negative electrode material and low-defect potassium manganese ferricyanide as the positive electrode material.

[0037] The active material on the negative electrode side is tellurium-doped sulfide polyacrylonitrile, and the negative electrode sheet is aluminum foil. The mass of the active material is 1 mg / cm³. -2 The active material on the positive electrode side is potassium manganese ferricyanide with low defects, and the positive electrode sheet is aluminum foil. The mass of the active material is 3.7 mg / cm³. -2 The above positive and negative electrodes were assembled into a coin cell, and its charge and discharge performance was tested.

[0038] Figure 1 The X-ray diffraction pattern of the prepared tellurium-doped sulfurized polyacrylonitrile shows no obvious diffraction peaks, indicating that the material has an amorphous structure. Scanning electron microscopy images show that the material exhibits an irregular spherical morphology (e.g., ...). Figure 2 (As shown). Elemental analysis results show that the prepared tellurium-doped compound contains 2.3 wt% tellurium, 37.4 wt% sulfur, and 60.1 wt% carbon. Electrochemical test results show that when used as a potassium storage anode material, at 0.1C (1C = 500 mAh g / L), -1 Under the conditions of ) rate expansion, its potassium storage capacity reaches as high as 546.8 mAh g. -1 (like Figure 3 (As shown). Even at 4C rate, it still has 369.1 mAh g. -1The capacity. Figure 4 The charge-discharge curve of the assembled full cell at 0.1C shows that the full cell has a capacity of 152.2 mAh g⁻¹. -1 The reversible specific capacity. Figure 5 The graph shows the cycling stability of the prepared full cell at 3C rate. Figure 5 It can be seen that the full battery has a capacity of 93.6 mAh g. -1 The reversible specific capacity still retains 89mAh g after 1000 cycles. -1 The specific capacity and capacity retention rate reached 95.1%, confirming that the full battery has excellent charge-discharge cycle performance.

[0039] Example 2

[0040] Step 1: Using elemental tellurium, elemental sulfur, and polyacrylonitrile as raw materials, tellurium-doped sulfurized polyacrylonitrile materials are prepared by thermal polymerization.

[0041] 0.015 g of elemental tellurium, 1 g of elemental sulfur, and 3 g of sulfurized polyacrylonitrile were weighed and mixed thoroughly. The mixture was then heat-treated at 350 °C for 5 hours under an argon atmosphere. After cooling, tellurium-doped sulfurized polyacrylonitrile material was obtained. The crystal structure, morphology, and chemical composition of the prepared sample were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and elemental analysis. A potassium metal half-cell was assembled using the tellurium-doped sulfurized polyacrylonitrile material as the positive electrode and potassium metal as the negative electrode. The performance of this material in the range of 0.1–2.5 V (vs. K) was tested. + Electrochemical performance in the / K voltage range.

[0042] Step two is the same as in Example 1.

[0043] The tellurium-doped polyacrylonitrile sulfide and potassium-ion full cells prepared in this embodiment are the same as those in Example 1, both exhibiting excellent electrochemical potassium storage performance.

[0044] The methods disclosed and proposed in this invention can be implemented by those skilled in the art by appropriately modifying the conditions and routes, etc. Although the methods and preparation techniques of this invention have been described through preferred embodiments, those skilled in the art can obviously modify or recombine the methods and technical routes described herein without departing from the content, spirit, and scope of this invention to achieve the final preparation technique. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the spirit, scope, and content of this invention.

Claims

1. A tellurium-doped sulfided polyacrylonitrile potassium storage anode material and a potassium-ion full battery, characterized in that, Includes the following steps: Step 1: Using elemental tellurium, elemental sulfur, and polyacrylonitrile as raw materials, tellurium-doped sulfurized polyacrylonitrile materials are prepared by thermal polymerization. Step 2: Assemble a potassium-ion full cell using tellurium-doped sulfide polyacrylonitrile as the negative electrode material and low-defect potassium manganese ferricyanide as the positive electrode material.

2. The preparation method according to claim 1, characterized in that, The mass ratio of elemental tellurium to elemental sulfur is 0 to 0.

02.

3. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of elemental sulfur to polyacrylonitrile is 1:1 to 1:

3.

4. The preparation method according to claim 1 or 2, characterized in that, The heat treatment temperature is 350–450℃.

5. The preparation method according to claim 1 or 2, characterized in that, The reaction atmosphere is nitrogen or argon.

6. The preparation method according to claim 1, characterized in that, Tellurium-doped sulfurized polyacrylonitrile was used as the negative electrode material, with a tellurium-doped sulfurized polyacrylonitrile loading of 1–5 mg / cm³. -2 .

7. The preparation method according to claim 1, characterized in that, Using low-defect potassium manganese ferricyanide as the positive electrode material, the loading of potassium manganese ferricyanide is 4–18 mg cm⁻¹. -2 ...

8. The potassium-ion full battery according to claims 1-7, characterized in that, The capacity ratio of the positive and negative electrodes is 0.9:1 to 0.95:

1.

9. The potassium-ion full battery according to claims 1-8, characterized in that, The operating voltage of the potassium-ion full cell is 0.5-4.2V.

10. The potassium-ion full battery according to claims 1-9, characterized in that, The potassium-ion full battery includes button cells and pouch cells.

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