Iodized polymer fast-charging negative electrode material, preparation method and application thereof

Abstract

The application belongs to the technical field of alkali metal ion batteries, and particularly relates to an iodized polymer fast-charging negative electrode material and a preparation method and application thereof. The iodized polymer fast-charging negative electrode material is formed by thermal polymerization of iodine element and conductive polymer, wherein the doping amount of iodine element is 1-60 wt%. The iodized polymer fast-charging negative electrode material is prepared by the following method: (1) mixing iodine and conductive polymer material in a certain proportion, and performing dry or wet ball milling treatment to uniformly mix the reactants; (2) placing the mixture in a tube furnace, and performing thermal polymerization treatment under inert atmosphere to form the iodized polymer fast-charging negative electrode material. The prepared iodized polymer fast-charging negative electrode material can simultaneously regulate the ion transmission channel in the active material, the electrode interface desolvation process, the SEI interface film composition and the alkali metal eliminating the deactivation of the negative electrode, thereby showing excellent fast-charging performance. The preparation method provided by the application is simple, efficient and easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of alkali metal ion battery technology, specifically relating to an iodide polymer fast-charging negative electrode material, its preparation method, and its application. Background Technology

[0002] Alkali metal (lithium, sodium, potassium, etc.) ion rechargeable batteries are a key new energy technology widely used in 3C products, electric vehicles, and energy storage. To meet market demands, the specific energy and fast-charging performance requirements for rechargeable batteries are increasingly stringent, making the development of anode materials with high specific capacity, long cycle life, and high rate performance crucial. Currently, graphite is commonly used as an anode material in commercial lithium-ion batteries due to its low cost and good cycle stability. However, graphite has a low specific capacity (375 mAh / g) and poor rate performance, and is prone to lithium plating during rapid charging and discharging, posing risks such as short circuits and explosions. Furthermore, due to its low interlayer spacing, graphite materials have poor performance in storing sodium and potassium ions. Therefore, developing fast-charging anode materials with high safety and high performance is of great significance for advancing the development of high-specific-energy, fast-charging rechargeable batteries.

[0003] Under high-rate current testing conditions, the electrochemical performance of electrode materials is related to a variety of factors, including: (1) the ion transport rate in the bulk phase of the active material; (2) the desolvation process of the electrolyte at the electrode interface; (3) the SEI film composition at the electrode interface; and (4) the deposition / precipitation of alkali metals on the electrode surface under high current conditions. Therefore, developing new negative electrode materials or technologies to solve the above problems, while improving the ion transport kinetics at the electrode bulk phase and interface, promoting the electrolyte desolvation rate at the electrode interface and regulating the SEI composition, and eliminating excessive deposition of alkali metals on the negative electrode, is of great significance for promoting the commercial application of alkali metal (lithium, sodium, potassium, etc.) ion fast-charging batteries. Summary of the Invention

[0004] The purpose of this invention is to provide an iodide polymer fast-charging anode material and its preparation method to solve the problems of low specific capacity and poor rate performance of current alkali metal ion secondary battery anodes. By synergistically regulating the ion transport channels inside the active material, the desolvation process at the electrode interface, and the SEI interface film composition, a high-performance and practical fast-charging anode material and its applications are provided.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: an iodide polymer fast-charging negative electrode material, which is thermally polymerized from elemental iodine and conductive polymer, wherein the iodine doping amount is 1-60wt%.

[0006] Preferably, the iodine doping amount in the iodinated polymer is 3.5 wt%.

[0007] Preferably, the conductive polymer material is polyacrylonitrile, polythiophene, polypyrrole, or polyimide.

[0008] The present invention also provides a method for preparing the iodide polymer fast-charging negative electrode material, comprising the following steps:

[0009] (1) Iodine and conductive polymer materials are mixed in a weight ratio of (1:10)-(10:1), and the mixture is subjected to dry or wet ball milling to ensure that the reactants are mixed evenly.

[0010] (2) The mixture is placed in a tube furnace and subjected to thermal polymerization under an inert atmosphere to generate iodinated polymer.

[0011] Preferably, in step (2), the temperature range of the thermal polymerization treatment is 200°C. o C-1500 o C.

[0012] The present invention further provides the application of the iodide polymer fast-charging negative electrode material in the preparation of alkali metal ion batteries.

[0013] The present invention further provides an alkali metal ion battery, wherein the alkali metal ion battery comprises the iodide polymer fast-charging negative electrode material, electrolyte, alkali metal and positive electrode material.

[0014] Preferably, the alkali metal salt is selected from any one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, sodium perchlorate, sodium hexafluorophosphate, sodium trifluoromethanesulfonate, potassium perchlorate, and potassium hexafluorophosphate.

[0015] Preferably, the electrolyte is selected from one or more of ethylene carbonate, dimethyl carbonate, fluoroethylene carbonate, propylene carbonate, and diethyl carbonate.

[0016] Preferably, the cathode material is selected from any one of the following: ternary lithium-ion battery cathode materials, lithium cobalt oxide, lithium iron phosphate, lithium-rich manganese-based materials, layered oxide sodium-ion cathode materials, Prussian blue / white sodium-ion cathode materials, and polyanionic compound sodium-ion cathode materials.

[0017] The advantages of this invention over the prior art are:

[0018] (1) In this method, the iodide polymer fast-charging negative electrode material is prepared by solid-phase synthesis. Iodine element is mechanically mixed with polymer precursor and calcined to polymerize. Iodine is uniformly dispersed in the target product in atomic form (CI). The iodide content is easy to control. The preparation method is simple, efficient and easy to industrialize.

[0019] (2) The prepared iodide polymer fast-charging anode material can simultaneously regulate the ion transport channels inside the active material, the desolvation process at the electrode interface, and the SEI interface film composition, and eliminate the alkali metals that deactivate the anode, thus exhibiting excellent fast-charging performance. The characteristics of this material include the following aspects: (a) The larger interlayer spacing promotes the ion transport kinetics inside the material; (b) The iodine on the polymer backbone contains abundant lone pairs of electrons, which can improve the surface potential, inner Helmholtz layer, and double layer structure of the material, and promote the formation of LiI / LiF SEI film; (c) Dissolved I - Ions regulate the solvation structure of the electrolyte and promote the desolvation process of the electrolyte; (d)I3 - / I - Reversible oxidation reaction effectively eliminates alkali metals that are deactivated at the negative electrode;

[0020] (3) The prepared iodide polymer fast-charging anode material has excellent fast-charging performance in various alkali metal (lithium, sodium, potassium, etc.) ion battery fields. Attached Figure Description

[0021] Figure 1 Scanning electron microscope image of iodinated polyacrylonitrile fast-charging negative electrode material;

[0022] Figure 2 X-ray photoelectron spectrum of I3d in iodinated polyacrylonitrile fast-charging anode material;

[0023] Figure 3 X-ray diffraction pattern of iodinated polyacrylonitrile fast-charging negative electrode material;

[0024] Figure 4 Zeta potential diagram for iodinated polyacrylonitrile fast-charging negative electrode material;

[0025] Figure 5 Iodized polyacrylonitrile fast-charging negative electrode material, rate performance in lithium-ion batteries;

[0026] Figure 6 As a fast-charging negative electrode material of iodinated polyacrylonitrile, it is used in lithium-ion batteries at 20 A g. -1 Cyclic performance under certain conditions;

[0027] Figure 7 It is a fast-charging negative electrode material for iodinated polyacrylonitrile, with LiNi 0.8 Co 0.1 Mn 0.1 O2 ternary material is used as the positive electrode, and fast charging performance is achieved under 5C conditions in lithium-ion full batteries;

[0028] Figure 8 The fast-charging performance of iodide polymer anode material is demonstrated under 5C conditions in lithium-ion full batteries, with lithium iron phosphate, lithium cobalt oxide and lithium-rich manganese-based materials as cathodes.

[0029] Figure 9 As a fast-charging negative electrode material of iodinated polypyrrole and iodinated polythiophene, it is used in lithium-ion batteries at 10 A g. -1 under conditions;

[0030] Figure 10 Rate performance of iodinated polyacrylonitrile fast-charging negative electrode material in sodium-ion batteries;

[0031] Figure 11 As a fast-charging negative electrode material of iodinated polyacrylonitrile, it is used in sodium-ion batteries at 5 A g. -1 Cyclic performance;

[0032] Figure 12 As an iodide polymer fast-charging negative electrode material, with polyanionic compounds, Prussian blue, and layered oxides as positive electrodes, respectively, the fast-charging performance under 5C conditions in sodium-ion full batteries is demonstrated. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0034] Example 1: The iodide polymer fast-charging negative electrode material of this example was prepared using the following method:

[0035] Take 0.4 g of polyacrylonitrile, 0.24 g of iodine, and 10 ml of anhydrous ethanol in a ball mill jar and ball mill at 100-500 rpm for 60-600 min. After centrifugation, washing, and drying, place the sample in a tube furnace under an argon atmosphere at 200-1500 °C. o Iodinated polyacrylonitrile with an iodine doping content of 3.5 wt% was prepared by calcination at C for 1-24 h.

[0036] In this embodiment, the morphology of the prepared iodinated polyacrylonitrile sample is as follows: Figure 1 As shown in Figure 2, X-ray photoelectron spectroscopy characterization revealed that iodine is incorporated into the iodide polyacrylonitrile backbone via CI bonds. Figure 3 As shown, X-ray diffraction characterization reveals that iodination treatment increases the interlayer spacing of the material, which facilitates rapid ion transport within the material. Figure 4As shown, the Zeta potential test results indicate that iodine in iodinated polyacrylonitrile materials contains abundant lone pairs of electrons, resulting in a high surface charge, which is beneficial for controlling the double-layer structure and fast-charging chemical performance of the material. Iodinated polyacrylonitrile with different iodine contents was prepared by changing the iodine feed ratio. An electrode was prepared by mixing the active material: Super P:PVDF in an 8:1:1 ratio and using 1 M LiPF6+FEC / DMC (1:1) as the electrolyte and lithium metal as the negative electrode. CR2025 coin cells were then prepared, and their rate performance and high-rate long-cycle performance were tested. Figure 5 , Figure 6 As shown.

[0037] The prepared iodide polymer material exhibits excellent fast-charging chemical performance in lithium-ion full batteries. LiNi was used. 0.8 Co 0.1 Mn 0.1 The full battery assembled with an O2 ternary cathode and an iodide polyacrylonitrile anode exhibits excellent fast-charging performance, such as... Figure 7 As shown. Furthermore, by using lithium iron phosphate, lithium cobalt oxide, and lithium-rich manganese-based materials, and employing iodinated polyacrylonitrile as the negative electrode, the assembled lithium-ion full battery exhibits excellent fast-charging performance, such as... Figure 8 As shown.

[0038] Example 2: In this example, the iodine doping ratio was varied to prepare polyacrylonitrile with iodide concentrations of 1 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt%, and the electrochemical performance of the lithium-ion battery was tested. To prepare polyacrylonitrile with iodide concentrations of 1 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt%, the feed ratios of each raw material were: polyacrylonitrile (0.4 g) / iodine (0.1 g), polyacrylonitrile (0.4 g) / iodine (0.34 g), polyacrylonitrile (0.4 g) / iodine (0.68 g), polyacrylonitrile (0.4 g) / iodine (1.0 g), and polyacrylonitrile (0.4 g) / iodine (2.0 g). Other processing methods were similar to those in Example 1.

[0039] Example 3: This example changes the type of polymer precursor, for example, using conductive polymers such as polythiophene, polypyrrole, and polyimide to prepare different types of iodinated polythiophene, iodinated polypyrrole, and iodinated polyimide fast-charging anode materials. Their fast-charging performance in lithium-ion batteries is as follows: Figure 9 As shown.

[0040] Example 4: This example utilizes the negative electrode material prepared in the previous example, fixing the lithium salt type and changing the solvent composition of the electrolyte system to study the electrochemical performance of iodinated polyacrylonitrile materials with different iodine contents in batteries with different electrolyte systems. For example, electrolyte systems such as 1 M LiPF6+EC / DMC, 1 M LiPF6+EC / DMC / EMC, and 1 M LiPF6+EC / DMC+FEC (different ratios) were studied, and the electrochemical performance of lithium-ion batteries was tested.

[0041] Example 5: This example keeps the solvent type constant and changes the lithium salt composition of the electrolyte system to study the electrochemical performance of iodinated polyacrylonitrile materials in batteries with single lithium salt or composite lithium salt electrolyte systems. For example, electrolyte systems such as 1 M LiPF6+EC / DMC / FEC, 1 M LiBF4+EC / DMC / FEC, 1 M LiTFSI+EC / DMC / FEC, 1 M LiFSI+EC / DMC / FEC, LiPF6 / LiBF4+EC / DMC / FEC, and LiPF6 / LiTFSI+EC / DMC / FEC were studied, and the electrochemical performance of the lithium-ion batteries was tested.

[0042] Example 6: This example investigates the fast-charging performance of iodine polymer anode materials in different types of alkali metal ion battery systems, including sodium-ion and potassium-ion batteries. For example, electrolyte systems such as 1 M NaClO4+FEC / DMC / EMC, 1 M NaClO4+PC, 1 M NaClO4+EC / DEC+FEC, 1 M KPF6+EC / DEC+FEC, and 1 M KPF6+PC / FEC were studied, and the electrochemical performance of the batteries was tested. The electrolytes are not limited to the above types; the electrolyte components can be single or combined sodium (potassium) salts, and single or combined solvents. Test results are as follows: Figure 10-11 As shown, iodinated polyacrylonitrile exhibits excellent rate performance and long cycle life in sodium-ion batteries.

[0043] Example 7: The prepared iodide polymer material exhibits excellent fast-charging performance in sodium-ion full batteries. For example... Figure 12 As shown, sodium-ion full cells assembled using layered oxide sodium-ion cathode material, Prussian blue / white, and polyanionic compounds as cathodes, and iodinated polymers as anodes, respectively, exhibit high reversible specific capacity and cycle stability under 5C conditions.

Claims

1. An iodide polymer fast-charging negative electrode material, characterized in that: It is made by thermal polymerization of elemental iodine and conductive polymer, wherein the iodine doping amount is 1-20wt%; the iodinated polymer fast-charging negative electrode material is prepared by the following method: (1) Iodine and conductive polymer material are mixed in a weight ratio of (1:10)-(10:1), and the mixture is subjected to dry or wet ball milling to make the reactants uniformly mixed; the conductive polymer material is polyacrylonitrile, polythiophene or polypyrrole; (2) After centrifugation, washing and drying, the sample is placed in a tube furnace and subjected to thermal polymerization under an inert atmosphere to generate iodide polymer fast-charging negative electrode material; the temperature range of thermal polymerization is 200℃-1500℃, and the time is 1-24 h.

2. The iodide polymer fast-charging negative electrode material according to claim 1, characterized in that: The iodide polymer contains 3.5 wt% iodine.

3. The application of the iodide polymer fast-charging negative electrode material as described in claim 1 in the preparation of alkali metal ion batteries.

4. An alkali metal ion battery, characterized in that: It comprises the iodinated polymer fast-charging negative electrode material as described in claim 1 or 2, the electrolyte solvent, the alkali metal salt, and the positive electrode material.

5. The alkali metal ion battery according to claim 4, characterized in that: The alkali metal salt is selected from any one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, sodium perchlorate, sodium hexafluorophosphate, sodium trifluoromethanesulfonate, potassium perchlorate, and potassium hexafluorophosphate.

6. The alkali metal ion battery according to claim 4, characterized in that: The electrolyte solvent is selected from one or more of ethylene carbonate, dimethyl carbonate, fluoroethylene carbonate, propylene carbonate, and diethyl carbonate.

7. The alkali metal ion battery according to claim 4, characterized in that: The cathode material is selected from any one of the following: ternary lithium-ion battery cathode materials, lithium cobalt oxide, lithium iron phosphate, layered oxide sodium-ion cathode materials, Prussian blue / white sodium-ion cathode materials, and polyanionic compound sodium-ion cathode materials.

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