Lithium ion battery material and preparation method therefor and use thereof

Abstract

The present disclosure provides a lithium ion battery material and a preparation method therefor and a use thereof. The structural formula of the lithium ion battery material is Li4ZrF8-2XOX, wherein 0<X≤0.15. According to the present disclosure, oxygen doping is carried out on a Li4ZrF8 material by means of a zirconium-containing oxide, and oxygen doping is carried out at position F, so that the ionic conductivity of the Li4ZrF8 material is greatly improved. When the Li4ZrF8-2XOX material is applied to a lithium ion battery, after the material reacts with water molecules in an electrolyte to generate hydroxyl, the water content in the electrolyte can be reduced.

Description

A lithium-ion battery material and its preparation method and application

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to the Chinese patent application with application number 202310656029.4 filed with the Chinese Patent Office on June 5, 2023, entitled “A lithium-ion battery material, its preparation method and application”. Technical Field

[0003] The present disclosure belongs to the technical field of battery materials, and in particular relates to a lithium-ion battery material and a preparation method and application thereof. Background Art

[0004] Lithium-ion batteries are currently the most mature and high-performance electrochemical energy storage devices. Their high density and low cost make them an ideal energy storage tool for new energy vehicles, photovoltaic power generation, and wind power. However, with the increasing diversification of application scenarios, the requirements for the safety, energy density, and lifespan of lithium-ion batteries have become increasingly stringent. Reducing the amount of electrolyte used and developing solid-state batteries has become an industry-wide consensus. However, due to the limitations of current material systems, process maturity, and manufacturing equipment, the industrialization of all-solid-state batteries remains very difficult. Under the condition of reducing the amount of electrolyte in the battery, the application of solid-state electrolyte materials with lithium-ion conductivity in the battery to prepare hybrid solid-liquid lithium-ion batteries has become the most practical development direction.

[0005] Fluoride solid electrolyte materials are one of the hot topics in current solid electrolyte research due to their wide electrochemical window and strong chemical stability. Among them, Li4ZrF8 material, as a type of fluoride solid electrolyte, has an electrochemical window of 1.21~6.38V according to theoretical calculations. Therefore, Li4ZrF8 has broad application prospects in high voltage systems. J Mlynáriková, et al. Solid state NMR and XPS of ternary fluorido-zirconates of various coordination modes [J]. Journal of Fluorine Chemistry, 2018, 208) disclosed: At a temperature of 363K, LiF (0.519g, 20.008mmol) and H2O (20cm 3 ) and stirred, then ZrF4 (1.675 g, 9.999 mmol) was added; the reaction mixture was boiled for 5 min, cooled to 363 K, and 10% HF (90 cm 3); when the solution begins to cool, small crystals begin to precipitate, and the solution is filtered through filter paper to remove the precursor to obtain Li4ZrF8 material. The above method for preparing Li4ZrF8 is cumbersome and time-consuming, and the ionic conductivity of the prepared Li4ZrF8 material is low.

[0006] The electrolytes currently used in lithium-ion batteries primarily consist of lithium salts and organic solvents, both of which readily absorb moisture from the environment. LiPF6, the most commonly used lithium salt, is highly soluble in water. In commercial lithium-ion batteries, the moisture content of the electrolyte is generally controlled at around 50 ppm. The hydrolysis reaction equation for LiPF6 can be expressed as: LiPF6 + H2O → POF3↑ + HF + LiF↓. Therefore, reducing the moisture content of the electrolyte has always been a key and challenging aspect of lithium-ion battery electrolyte research and development.

[0007] Summary of the Invention

[0008] In view of this, the purpose of the present disclosure is to provide a lithium ion battery material and its preparation method and application, the material has high ionic conductivity; the present disclosure also provides a solid electrolyte material for solid-liquid mixing, Li4ZrF 8-2X O X When the material is used in lithium-ion batteries, it is in full contact with the electrolyte, which helps to reduce the moisture in the electrolyte and improve the cycle stability of the battery.

[0009] The present disclosure provides a lithium ion battery material having the structural formula Li4ZrF 8-2X O X , 0 <X≤0.15。

[0010] The present disclosure provides a method for preparing a lithium-ion battery material, comprising the following steps:

[0011] Mixing a zirconium source, a lithium source, and a fluorine-containing acid solution, and filtering after reaction to obtain a precursor;

[0012] ball milling the precursor and the zirconium-containing oxide in a medium to obtain a slurry;

[0013] The slurry is dried and sintered to obtain a lithium-ion battery material having the following general formula:

[0014] Li4Zr 8-2X O X , 0 <X≤0.15。

[0015] In the present disclosure, the zirconium source is zirconium carbonate; the lithium source is selected from lithium carbonate and / or lithium hydroxide;

[0016] The fluorine-containing acid solution is selected from hydrofluoric acid;

[0017] The zirconium-containing oxide is selected from one or more of zirconium oxide, lithium zirconate and zirconium hydroxide;

[0018] The medium is selected from one or more of ethanol, isopropanol, n-butanol, n-hexane, N-methylpyrrolidone, acetonitrile, dimethylformamide and dimethyl sulfoxide.

[0019] In the present disclosure, the sintering temperature is 400-800° C., and the sintering time is 12-24 hours.

[0020] The lithium-ion battery material described in the above technical solution or the lithium-ion battery material prepared by the preparation method described in the above technical solution is used as a solid electrolyte in positive electrode coating materials, electrolyte additives, positive electrode plate additives, negative electrode plate additives or diaphragm coating materials.

[0021] The present disclosure provides a coating process for a positive electrode material, comprising the following steps:

[0022] The lithium-ion battery material described in the above technical solution is used as a solid electrolyte, and the lithium-ion battery material Li4ZrF 8-2X O X It is coated on the surface of the positive electrode material and then sintered;

[0023] The sintering temperature is 300-600°C and the sintering time is 5-10 hours;

[0024] The rotation speed of the coating equipment is 10 to 550 rpm, and the coating time is 1 to 3 hours.

[0025] The present disclosure provides a solid electrolyte material for solid-liquid mixing, including the lithium-ion battery material Li4ZrF 8-2X O X and electrolyte;

[0026] The electrolyte includes LiPF6.

[0027] The present disclosure provides a use of a solid electrolyte material for solid-liquid mixing, and the solid electrolyte material for solid-liquid mixing described in the above technical solution is applied to energy storage systems of lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, aluminum-ion batteries and fuel cells.

[0028] The present disclosure provides a battery comprising a pole piece and an electrolyte, wherein the pole piece comprises an active material and the lithium-ion battery material according to the above technical solution mixed in the active material;

[0029] The electrolyte includes LiPF6.

[0030] The present disclosure provides a battery comprising a coated separator and an electrolyte;

[0031] The coated separator includes a base film and the lithium-ion battery material described in the above technical solution coated on the surface of the base film;

[0032] The electrolyte includes LiPF6.

[0033] The present disclosure provides a lithium-ion battery material with a structural formula of Li4ZrF 8-2X O X , where 0 < X ≤ 0.15. The present disclosure performs oxygen doping on the Li4ZrF8 material through zirconium-containing oxides, and the composition of the doped material is: Li4ZrF 8-2X O X ; by performing oxygen doping at the F site, a significant increase in the ionic conductivity of the Li4ZrF8 material is achieved. In addition, the preparation method of the lithium-ion battery material is simple and easy to operate.

[0034] The present disclosure also provides a solid electrolyte material for solid-liquid mixing. When the Li4ZrF 8-2X O X material is applied to a lithium-ion battery, it is in full contact with the electrolyte. There is a trace amount of water (≤50 ppm) in the current commercial electrolyte. Since the electronegativity of fluorine is much greater than that of hydrogen and oxygen, the fluoride bonds formed with metal ions are extremely stable and difficult to break. Therefore, it is difficult for fluoride crystals to generate free metal ions and fluoride ions on the surface, and thus it is impossible to react with water molecules to form hydroxyl groups. The present disclosure changes the surface state of the Li4ZrF 8-2X O X material by performing oxygen doping at the F site. When in full contact with the electrolyte, the Li4ZrF 8-2X O X material can react with the trace amount of water (≤50 ppm) in the electrolyte, generating hydroxyl groups on the surface of part of the Li4ZrF 8-2X O X material to form Li4ZrF 8-2X O X ·(OH) y , which is beneficial to removing the water in the electrolyte and effectively reducing the hydrolysis side reaction of LiPF6. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 is a diffraction pattern of the crystal structure of Li4ZrF 7.7 O 0.15 prepared in Example 1 of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present disclosure provides a lithium-ion battery material with a structural formula of Li4ZrF 8-2X O X , where 0 < X ≤ 0.15.

[0037] In the present disclosure, X is 0.15, 0.05, 0.1, 0.12 or 0.14.

[0038] The present disclosure provides a method for preparing a lithium-ion battery material, comprising the following steps:

[0039] Mixing a zirconium source, a lithium source, and a fluorine-containing acid solution, reacting and filtering to obtain a precursor;

[0040] ball milling the precursor and the zirconium-containing oxide in a medium to obtain a slurry;

[0041] The slurry is dried and sintered to obtain a lithium-ion battery material having the following general formula: Li4ZrF 8-2X O X , 0 <X≤0.15。

[0042] The present invention uses oxygen doping at the F site to partially dope the F site with oxygen. Due to the high electronegativity of the F element, the Li + The adsorption capacity of Li + Migration is hindered, and the F element occupies a relatively large position in the Li4ZrF8 material. Therefore, an appropriate amount of oxygen doping can significantly improve the ionic conductivity of the Li4ZrF8 material. The method provided by the present disclosure is low-cost, simple to operate, easy to implement, and suitable for industrial mass production.

[0043] In the present disclosure, the zirconium source is zirconium carbonate; and the lithium source is selected from lithium carbonate and / or lithium hydroxide.

[0044] In the present disclosure, the zirconium-containing oxide is selected from one or more of zirconium oxide, lithium zirconate, and zirconium hydroxide. The zirconium-containing oxide provides the O element, which is doped in some F sites, thereby significantly improving the ionic conductivity of the Li4ZrF8 material.

[0045] In the present disclosure, the medium is selected from one or more of ethanol, isopropanol, n-butanol, n-hexane, N-methylpyrrolidone, acetonitrile, dimethylformamide and dimethyl sulfoxide.

[0046] In the present disclosure, the reaction time after the zirconium source, lithium source and fluorine-containing acid solution are mixed is 4.5 to 5.5 hours; in a specific embodiment, the reaction time is 5 hours.

[0047] In the present disclosure, the fluorine-containing acid solution is selected from hydrofluoric acid; the hydrofluoric acid is a 40wt% hydrogen fluoride aqueous solution. The medium used in ball milling is selected from one or more of ethanol, isopropanol, n-butanol, n-hexane, NMP (N-methylpyrrolidone), acetonitrile (CH3CN), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). The ball mill uses zirconium balls with a diameter of 0.1mm to 3mm; in a specific embodiment, the ball mill uses 1mm zirconium balls or 0.5mm zirconium balls. The lithium-ion battery material is in powder form.

[0048] In the present disclosure, the sintering temperature is 400-800°C, and the sintering time is 12-24 hours. In a specific embodiment, the sintering temperature is 600°C, 800°C, 400°C, or 500°C, and the sintering time is 12 hours.

[0049] The present invention discloses oxygen doping of Li4ZrF8 material by zirconium oxide, and the composition of the doped material is: Li4ZrF 8-2X O X The present invention discloses a lithium-ion battery material Li4ZrF prepared by oxygen doping at the F position. 8-2X O X Reacting with trace amounts of water in the electrolyte, Li4ZrF 8-2X O X Hydroxyl groups are generated on the surface of the material; in addition, the ionic conductivity of the Li4ZrF8 material is greatly improved.

[0050] In a specific embodiment, X in the lithium-ion battery material is 0.15, 0.05, 0.1, 0.12 or 0.14.

[0051] The present disclosure provides a coating process for a positive electrode material, comprising the following steps:

[0052] The lithium-ion battery material described in the above technical solution is used as a solid electrolyte, and the lithium-ion battery material Li4ZrF 8-2X O X It is coated on the surface of the positive electrode material and then sintered;

[0053] The sintering temperature is 300-600°C and the sintering time is 5-10 hours;

[0054] The rotation speed of the coating equipment is 10 to 550 rpm, and the coating time is 1 to 3 hours.

[0055] In the present disclosure, the positive electrode material and the lithium ion battery material Li4ZrF prepared by the preparation method described in the above technical solution 8-2X O XThe mass ratio of is 95 to 105: 1. The present disclosure found that after oxygen doping at the F position, the crystal structure still belongs to the orthorhombic system and the Pnma space group.

[0056] Since the 3d orbital of Ni in the positive electrode material overlaps with the 2p orbital of oxygen, as the applied voltage increases, in the highly delithiated state (highly charged state), O 2- Oxidation, the formation of peroxide species or superoxide species, the electrode deoxidation, so that the transition metal ions form unstable highly oxidizing byproducts, resulting in the occurrence of interfacial phase transition, Li4ZrF 8-2X O X After the material is coated with the ternary cathode material, the surface Li4ZrF 8-2X O X When the material comes into contact with the electrolyte, Li4ZrF 8-2X O X After reacting with water molecules in the electrolyte to generate hydroxyl groups on the surface, Li4ZrF 8-2X O X ·(OH) y , which is beneficial to reduce the moisture in the electrolyte and improve the cycle stability of the battery.

[0057] In the present disclosure, the positive electrode material is LiNi x Co y M 1-x-y O2; M=Al or Mn, 0.8≤x<1, 0≤y≤0.2; when M=Al, the above-mentioned ternary positive electrode material can be abbreviated as NCA, and when M=Mn, the above-mentioned ternary positive electrode material can be abbreviated as NCM.

[0058] The equipment used in the coating process of the present disclosure includes but is not limited to a high-speed mixer or a three-dimensional mixer. In the present disclosure, the rotation speed used in the coating process is 10 to 550 rpm, and the coating time is 1 to 3 hours.

[0059] The present disclosure preferably uses the above-mentioned coated ternary positive electrode material as a positive electrode to prepare a button battery, wherein the button battery comprises the coated ternary positive electrode material prepared by the preparation method described in the above technical solution and an electrolyte;

[0060] The electrolyte includes lithium salt and a mixed solvent; the mixed solvent is a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate.

[0061] In a specific embodiment, the lithium salt is selected from LiPF6; the mixed solvent is specifically a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate in a volume ratio of 1:1:1.

[0062] The present disclosure provides a solid electrolyte material for solid-liquid mixing, including the lithium-ion battery material Li4ZrF 8-2X OX and electrolyte;

[0063] The electrolyte includes LiPF6.

[0064] The present disclosure provides a use of a solid electrolyte material for solid-liquid mixing, and the solid electrolyte material for solid-liquid mixing described in the above technical solution is applied to energy storage systems of lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, aluminum-ion batteries and fuel cells.

[0065] The present disclosure provides a battery comprising a pole piece and an electrolyte, wherein the pole piece comprises an active material and the lithium-ion battery material according to the above technical solution mixed in the active material;

[0066] The electrolyte includes LiPF6.

[0067] In the present disclosure, the electrode sheet is a positive electrode sheet or a negative electrode sheet. If it is a positive electrode sheet, the active material is a positive electrode active material, and the mass ratio of the positive electrode active material to the lithium-ion battery material is 100:0.95-1.05. The mixed solvent in the electrolyte is preferably a mixture of ethylene carbonate, dimethyl carbonate, and diethyl carbonate in a volume ratio of 1:1:1. If it is a negative electrode sheet, the active material is a negative electrode active material, and the mass ratio of the negative electrode active material to the lithium-ion battery material is 100:0.95-1.05. The mixed solvent in the electrolyte is preferably a mixture of ethylene carbonate, dimethyl carbonate, and diethyl carbonate in a volume ratio of 1:1:1.

[0068] In the battery, lithium-ion battery materials are mixed in the pole pieces. As electrodes, they react with water molecules in the electrolyte to generate hydroxyl groups on the surface, which helps to reduce the moisture in the electrolyte and improve the cycle stability of the battery.

[0069] The present disclosure provides a battery comprising a coated separator and an electrolyte;

[0070] The coated diaphragm comprises a base film and the lithium-ion battery material described in the above technical solution coated on the surface of the base film;

[0071] The electrolyte includes LiPF6.

[0072] The coated diaphragm includes the lithium ion battery material described in the above technical solution, which reacts with water molecules in the electrolyte to generate hydroxyl groups on the surface, which is beneficial to reducing the moisture in the electrolyte and improving the cycle stability of the battery.

[0073] This disclosure uses the following methods to apply and test materials:

[0074] 1. Ionic conductivity test

[0075] Take 0.1~5g of the above Li4ZrF8-2X O X Materials. Use a mold with a diameter of 10mm to 15mm, apply a pressure of 5 to 15MPa in a desktop powder tablet press, maintain the pressure for 10 to 20 minutes, and then demold to obtain a thin sheet. Place the above-mentioned thin sheet in a sintering furnace, heat it to 300 to 600℃ at 1 to 3℃, and keep it warm for 12 to 20 hours. The ceramic sheet required for the test can be obtained. Use 1000-grit sandpaper moistened with alcohol to gently polish the surface of the above-mentioned ceramic sheet according to the cross-cross method to remove surface impurities and ensure that the thickness of the electrolyte is uniform at all positions. Use a vernier caliper to measure the thickness L of the sintered sheet, use an ion sputtering instrument to evaporate gold blocking electrodes, and use AC impedance to test Li4ZrF 8-2X O X The ionic conductivity of the material.

[0076] 2. Li4ZrF 8-2X O X Coated diaphragm

[0077] The base film is a polyolefin diaphragm, including but not limited to polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), and polypropylene (PP); PE and PP are preferably used as the base film.

[0078] The base film thickness is 5 to 30 μm, preferably 7 μm, 9 μm, or 12 μm;

[0079] For double-sided coating of Li4ZrF 8-2X O X The material has a coating thickness of 0.5 to 5 μm, preferably 1 μm, 2 μm, or 3 μm.

[0080] The electrolyte was prepared by dissolving 1M LiPF6 in ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (EMC) (volume ratio of 1:1:1). In a glove box filled with argon, the double-sided coated diaphragm was placed in the electrolyte and soaked at 25°C for 72 hours before being taken out. During this process, the water and oxygen value in the glove box was controlled to be less than 0.01ppm. The water value in the electrolyte before and after the diaphragm was tested, and the Li4ZrF 8-2X O X The moisture content test of the material coating membrane before and after immersion is shown in Table 2.

[0081] 3. Li4ZrF 8-2X O X Ternary material (NCM or NCA) testing after material coating;

[0082] 2032 button cells were assembled in an argon-filled glove box, with the water and oxygen content in the glove box controlled to less than 0.01 ppm. A coated ternary material (NCM or NCA) served as the positive electrode, polypropylene as the separator, nickel foam as the structural support and conductor, and graphite as the negative electrode. An electrolyte solution of 1M LiPF6 was prepared in a 1:1:1 volume ratio of ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (EMC). Half-cells were assembled and sealed with a sealing machine. After a period of quiescence, electrochemical performance testing was performed. Battery testing was performed at a constant temperature of 25°C using a charge-discharge cycle consisting of a 30-minute constant current charge followed by a constant voltage charge and discharge cycle. Cycling performance was tested by first activating the battery with a low current of 0.1C three times, followed by 100 cycles of constant current charge and discharge at 0.5C. For the rate performance test, the battery was charged and discharged at a constant current of 0.1C in the voltage range of 2.75 to 4.3V.

[0083] 4. Li4ZrF 8-2X O X Material positive electrode sheet blending

[0084] Li4ZrF 8-2X O X The material was blended into the positive electrode sheet according to 1% of the mass of the positive electrode active material, and the blended positive electrode sheet was prepared into a soft-pack battery, and the capacity retention rate of the soft-pack battery after different cycles was tested.

[0085] 5. Li4ZrF 8-2X O X Material negative electrode sheet blending

[0086] Li4ZrF 8-2X O X The material was blended into the negative electrode sheet according to 1% of the mass of the negative electrode active material, and the blended negative electrode sheet was prepared into a soft-pack battery, and the capacity retention rate of the soft-pack battery after different cycles was tested.

[0087] To further illustrate the present disclosure, a preparation method of a lithium-ion battery material and its application provided by the present disclosure are described in detail below in conjunction with examples, but they should not be construed as limiting the scope of protection of the present disclosure.

[0088] Example 1 (X=0.15, using lithium zirconate for oxygen doping)

[0089] 1. Material preparation

[0090] 1. Zirconium carbonate, hydrofluoric acid (40wt.% hydrogen fluoride aqueous solution), lithium carbonate, lithium zirconate according to Li4ZrF 8-2X O X(X = 0.15) stoichiometric ratio weighing, wherein the amount of hydrofluoric acid added is calculated according to the actual proportion of hydrogen fluoride. First, 200.678g of weighed zirconium carbonate, 385.116g of hydrofluoric acid, and 144.086g of lithium carbonate are mixed and reacted for 5 hours, and then the precursor is filtered out. The above precursor and 7.655g of lithium zirconate are ball-milled for 3 hours in a ball-milling medium, wherein the ball-milling medium is: isopropyl alcohol, and zirconium balls with a diameter of 1mm are used for grinding;

[0091] The slurry after ball milling is dried and the dried powder is placed in a sintering furnace and sintered at 800℃ for 12h to obtain Li4ZrF 7.7 O 0.15 (X=0.15) Powder material.

[0092] As shown in Figure 1, Li4ZrF 7.7 O 0.15 The crystal structure diffraction data shows that after oxygen doping at the F position, the crystal structure still belongs to the orthorhombic system and the Pnma space group.

[0093] 2. Material Application and Testing

[0094] 1. Ionic conductivity test

[0095] Take 1g of the above Li4ZrF 7.7 O 0.15 Materials. Use a mold with a diameter of 10 mm, apply a pressure of 10 MPa in a desktop powder tablet press, maintain the pressure for 10 minutes, and then demold to obtain a thin sheet. Place the above-mentioned thin sheet in a sintering furnace, heat it to 300 ° C at 1 ° C, and keep it warm for 12 hours. The ceramic sheet required for the test can be obtained. Use 1000 mesh sandpaper moistened with alcohol to gently polish the surface of the above-mentioned ceramic sheet according to the cross-cross method to remove surface impurities and ensure that the thickness of the electrolyte is uniform at all positions. Use a vernier caliper to measure the thickness L of the sintered sheet, use an ion sputtering instrument to evaporate gold blocking electrodes, and use AC impedance to test Li4ZrF 7.7 O 0.15 The ionic conductivity of the material, the test data is shown in Table 1.

[0096] 2. Li4ZrF 7.7 O 0.15 Coated diaphragm

[0097] PE is selected as the base film with a thickness of 5 μm. 7.7 O 0.15The material has a coating thickness of 1 μm. The electrolyte is prepared by dissolving 1M LiPF6 in ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (EMC) (the volume ratio is 1:1:1). In a glove box filled with argon, the double-sided coated diaphragm is placed in the electrolyte and soaked at 25°C for 72 hours before being taken out. During this process, the water and oxygen value in the glove box is controlled to be less than 0.01ppm. The moisture value in the electrolyte before and after the diaphragm is soaked is tested and recorded in Table 2.

[0098] 3. Li4ZrF 7.7 O 0.15 Testing of ternary materials (NCM or NCA) after material coating

[0099] Li4ZrF 7.7 O 0.15 The powder material and the ternary cathode material NCM811 are weighed in a mass ratio of 1:100, i.e. Li4ZrF 7.7 O 0.15 10g of powder material and 1000g of NCM811 material were fed into the coating machine at a speed of 200r / min. After 1 hour, the materials were taken out and placed in a sintering furnace at 600℃ for 10 hours.

[0100] 2032 button-type cells were assembled in an argon-filled glove box, with the water and oxygen concentration in the glove box controlled to less than 0.01 ppm. The positive electrode was made of coated NCM811 ternary material, the separator was polypropylene (PE), nickel foam provided structural support and conductivity, and graphite served as the negative electrode. The electrolyte was prepared by dissolving 1M LiPF6 in ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (EMC) (1:1:1 by volume). Half-cells were assembled and sealed with a sealer. After a period of quiescence, electrochemical performance was tested. Testing was conducted at a constant temperature of 25°C using a charge-discharge profile consisting of a 30-minute constant current charge followed by a constant voltage charge and discharge cycle. Cycling performance was tested by first activating the cells with a low current of 0.1C three times, followed by 100 cycles of constant current charge and discharge at 0.5C. Rate performance was tested by charging and discharging the cells at a constant current of 0.1C over a voltage range of 2.75 to 4.3V. The test results are shown in Table 3.

[0101] 4. Li4ZrF 7.7 O 0.15 Material positive electrode sheet blending

[0102] Li4ZrF 7.7 O 0.15The material was blended into the ternary positive electrode sheet at 1% of the mass of the positive electrode active material (NCM). The above-mentioned blended positive electrode sheet, graphite negative electrode sheet, polyolefin separator and 1M LiPF6 were dissolved in ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (EMC) (the volume ratio was 1:1:1) to prepare an electrolyte to prepare a soft pack battery. The cycle performance capacity retention rate of the soft pack battery was tested at a constant temperature of 25°C. The voltage range was 2.75~4.2V, the charge and discharge current was 1.0C / 1.0C, and the test data was recorded in Table 4.

[0103] 5. Li4ZrF 7.7 O 0.15 Material negative electrode sheet blending

[0104] Li4ZrF 7.7 O 0.15 The material was blended into the graphite negative electrode sheet at 1% of the mass of the graphite negative electrode active material. The blended graphite negative electrode sheet, positive electrode sheet, polyolefin separator, and 1M LiPF6 were dissolved in ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (EMC) (volume ratio of 1:1:1) to prepare an electrolyte to prepare a soft pack battery. The cycle performance capacity retention rate of the soft pack battery was tested at a constant temperature of 25°C. The voltage range was 2.75~4.2V, and the charge and discharge current was 1.0C / 1.0C. The test data is recorded in Table 5.

[0105] Example 2 (X=0.05, using zirconium oxide for oxygen doping)

[0106] 1. Material preparation

[0107] Zirconium carbonate, hydrofluoric acid (40 wt.% hydrogen fluoride aqueous solution), lithium carbonate, zirconium oxide according to Li4ZrF 8-2X O X (X = 0.05) stoichiometric ratio weighing, wherein the amount of hydrofluoric acid added is calculated according to the actual proportion of hydrogen fluoride. First, 205.959g of weighed zirconium carbonate, 395.119g of hydrofluoric acid, and 147.78g of lithium carbonate are mixed and reacted for 5 hours, and then the precursor is filtered out. The above precursor is ball-milled with 3.081g of zirconium oxide in a ball-milling medium for 3 hours; wherein the ball-milling medium is: ethanol, and the grinding is performed with zirconium balls with a diameter of 1mm;

[0108] The slurry after ball milling is dried and the dried powder is placed in a sintering furnace at 600℃ for 12h to obtain Li4ZrF 7.9 O 0.05 (X=0.05) powder material.

[0109] 2. Material Application and Testing

[0110] The ion conductivity test, diaphragm coating test, positive electrode sheet blending test, and negative electrode sheet blending test are the same as those in Example 1.

[0111] When coating the ternary cathode material, Li4ZrF 7.9 O 0.05 The powder material and the ternary cathode material NCM811 are weighed in a weight ratio of 1:95, i.e. Li4ZrF 7.9 O 0.05 10g of powder material and 950g of NCM811 material were fed into a coating machine at a speed of 200 rpm. After 1 hour, the materials were removed and placed in a sintering furnace at 600°C for 10 hours. The button cell assembly and electrical performance testing were the same as in Example 1.

[0112] Example 3 (X=0.1, using zirconium oxide for oxygen doping)

[0113] 1. Material preparation

[0114] Zirconium carbonate, hydrofluoric acid (40 wt.% hydrogen fluoride aqueous solution), lithium carbonate, zirconium oxide according to Li4ZrF 8-2X O X (X=0.1) stoichiometric ratio weighing, wherein the amount of hydrofluoric acid added is calculated according to the actual proportion of hydrogen fluoride. First, 200.678g of weighed zirconium carbonate, 390.117g of hydrofluoric acid, and 147.78g of lithium carbonate are mixed and reacted for 5 hours, and then the precursor is filtered out. The above precursor is ball-milled with 6.161g of zirconium oxide in a ball-milling medium for 4 hours; wherein the ball-milling medium is: n-butanol, and the grinding is performed with zirconium balls with a diameter of 0.5mm;

[0115] The slurry after ball milling is dried and the dried powder is placed in a sintering furnace at 400℃ for 12h to obtain Li4ZrF 7.8 O 0.1 (X=0.1) Powder material.

[0116] 2. Material Application and Testing

[0117] The ion conductivity test, diaphragm coating test, positive electrode sheet blending test, and negative electrode sheet blending test are the same as those in Example 1.

[0118] Li4ZrF 7.8 O 0.1 The powder material and the ternary cathode material NCM811 are weighed in a weight ratio of 1:100, i.e. Li4ZrF 7.8 O 0.110g of powder material and 1000g of NCM811 material were fed into a coating machine at a speed of 200 rpm. After 1 hour, the materials were removed and placed in a sintering furnace at 600°C for 10 hours. The button cell assembly and electrical performance testing were the same as in Example 1.

[0119] Example 4 (X=0.12, using zirconium oxide for oxygen doping)

[0120] 1. Material preparation

[0121] Zirconium carbonate, hydrofluoric acid (40 wt.% hydrogen fluoride aqueous solution), lithium carbonate, zirconium oxide according to Li4ZrF 8-2X O X (X = 0.12) stoichiometric ratio weighing, wherein the amount of hydrofluoric acid added is calculated according to the actual proportion of hydrogen fluoride. First, 198.566g of weighed zirconium carbonate, 388.116g of hydrofluoric acid, and 147.78g of lithium carbonate are mixed and reacted for 5 hours, and then the precursor is filtered out. The above precursor is ball-milled with 7.393g of zirconium oxide in a ball-milling medium for 4 hours; wherein the ball-milling medium is: ethanol, and the grinding is performed with zirconium balls with a diameter of 1mm;

[0122] The slurry after ball milling is dried and the dried powder is placed in a sintering furnace and sintered at 800℃ for 12h to obtain Li4ZrF 7.8 O 0.1 (X=0.1) Powder material.

[0123] 2. Material Application and Testing

[0124] The ion conductivity test, diaphragm coating test, positive electrode sheet blending test, and negative electrode sheet blending test are the same as those in Example 1.

[0125] Li4ZrF 7.8 O 0.1 The powder material and the ternary cathode material NCM811 are weighed in a weight ratio of 1:105, i.e. Li4ZrF 7.8 O 0.1 10g of powder material and 1050g of NCM811 material were fed into a coating machine at a speed of 200 rpm. After 1 hour, the materials were removed and placed in a sintering furnace at 600°C for 10 hours. The button cell assembly and electrical performance testing were the same as in Example 1.

[0126] Example 5 (X=0.14, using zirconium hydroxide for oxygen doping)

[0127] 1. Material preparation

[0128] Zirconium carbonate, hydrofluoric acid (40 wt.% hydrogen fluoride aqueous solution), lithium carbonate, zirconium hydroxide according to Li4ZrF 8-2X OX (X=0.1) stoichiometric ratio weighing, wherein the amount of hydrofluoric acid added is calculated according to the actual proportion of hydrogen fluoride. First, 196.453g of weighed zirconium carbonate, 386.116g of hydrofluoric acid, and 95.792g of lithium hydroxide are mixed and reacted for 5 hours, and then the precursor is filtered out. The above precursor and 11.148g of zirconium hydroxide are ball-milled in a ball-milling medium for 4 hours; wherein the ball-milling medium is: ethanol, and zirconium balls with a diameter of 1mm are used for grinding;

[0129] The slurry after ball milling is dried and the dried powder is placed in a sintering furnace and sintered at 500℃ for 12h to obtain Li4ZrF 7.72 O 0.14 (X=0.14) Powder material.

[0130] 2. Material Application and Testing

[0131] The ion conductivity test, diaphragm coating test, positive electrode sheet blending test, and negative electrode sheet blending test are the same as those in Example 1.

[0132] Li4ZrF 7.72 O 0.14 The powder material and the ternary cathode material NCA are weighed in a weight ratio of 1:100, i.e. Li4ZrF 7.72 O 0.14 10g of powder material and 1000g of NCA material were fed into a coating machine at a speed of 200 rpm. After 1 hour, the materials were removed and placed in a sintering furnace at 600°C for 10 hours. The button cell assembly and electrical performance testing were the same as in Example 1.

[0133] Comparative Example 1

[0134] 1. Material preparation

[0135] Zirconium carbonate, hydrofluoric acid (40 wt.% hydrogen fluoride aqueous solution), lithium carbonate were mixed according to Li4ZrF 8-2X O X (X=0) Stoichiometric weighing, where the amount of hydrofluoric acid added is calculated based on the actual proportion of hydrogen fluoride. First, 211.24g of zirconium carbonate, 400.12g of hydrofluoric acid, and 147.78g of lithium carbonate are mixed and reacted for 5 hours. The precursor is then filtered to obtain Li4ZrF8.

[0136] 2. Material Application and Testing

[0137] The ion conductivity test, diaphragm coating test, positive electrode sheet blending test, and negative electrode sheet blending test are the same as those in Example 1.

[0138] Li4ZrF8 powder and NCA were weighed in a 1:100 weight ratio (10g Li4ZrF8 powder and 1000g NCA). The materials were fed into a coating machine at a speed of 200 rpm. After 1 hour, the materials were removed from the coating machine and placed in a sintering furnace at 400°C for 10 hours. The button cells were assembled and the electrical performance tested as in Example 1.

[0139] The data of ionic conductivity test of Examples and Comparative Examples are shown in Table 1; Li4ZrF 8-2X O X The moisture content test data before and after immersion of the material coating membrane is shown in Table 2; the electrical performance test data after coating the positive electrode is shown in Table 3; Li4ZrF 8-2X O X The test results of assembled soft pack battery after coating the positive electrode are shown in Table 4; Li4ZrF 8-2X O X The test results of the soft pack battery assembled after coating the negative electrode material are shown in Table 5.

[0140] Table 1 Li4ZrF 8-2X O X Material ionic conductivity test

[0141] The lithium ion battery material Li4ZrF prepared in Examples 1 to 5 of the present disclosure 8-2X O X Reacting with trace amounts of water in the electrolyte, Li4ZrF 8-2X O X Hydroxyl groups are generated on the surface of the material.

[0142] Table 2 Li4ZrF 8-2X O X Moisture content test of material coating membrane before and after immersion

[0143] Table 3 Li4ZrF 8-2X O X After the material is coated on the positive electrode, button battery testing is assembled

[0144] Table 4 Li4ZrF 8-2X O X Material positive electrode plate coating and assembled soft pack battery test

[0145] Table 5 Li4ZrF 8-2X O X Material negative electrode plate coating and assembled soft pack battery test

[0146] As can be seen from the above embodiments, the present disclosure provides a lithium-ion battery material with a structural formula of Li4ZrF 8-2X O X , where 0 < X ≤ 0.15. The present disclosure conducts oxygen doping on the Li4ZrF8 material through zirconium-containing oxides, and the composition of the doped material is: Li4ZrF 8-2X O X ; by performing oxygen doping at the F site, a significant increase in the ionic conductivity of the Li4ZrF8 material is achieved.

[0147] The present disclosure also provides a solid electrolyte material for solid-liquid mixing. When the Li4ZrF 8-2X O X material is applied to a lithium-ion battery, the Li4ZrF 8-2X O X material is in full contact with the electrolyte. There is a trace amount of water (≤50 ppm) in the current commercial electrolyte. Since the electronegativity of fluorine is much greater than that of hydrogen and oxygen, the fluoride bonds formed with metal ions are extremely stable and不易断裂. Therefore, it is difficult for fluoride crystals to generate free metal ions and fluoride ions on the surface, and thus it is impossible to react with water molecules to form hydroxyl groups. By performing oxygen doping at the F site, the present disclosure changes the surface state of the Li4ZrF 8-2X O X material. When in contact with the electrolyte, the Li4ZrF 8-2X O X material can react with trace amounts of water in the electrolyte, and the water binds to the surface of part of the Li4ZrF 8-2X O X material to generate Li4ZrF 8-2X O X ·(OH) y , thereby eliminating a certain amount of water in the electrolyte and effectively reducing the hydrolysis side reaction of LiPF6.

[0148] Experimental results show that: the ionic conductivity of the Li4ZrF 8-2X O X material is 2.1×10 -4 ~4.3×10 -4 S / m; after the Li4ZrF 8-2X O X material is coated on the separator and immersed in the electrolyte, the moisture in the electrolyte is reduced from 43 - 48 ppm to within the range of 4 - 7 ppm; the capacity retention rate of the coated ternary cathode at 0.5C@50 cycles is 92 - 96%, and the capacity retention rate at 0.5C@100 cycles is 91 - 94%; the Li4ZrF 8-2X O XThe positive electrode sheet prepared by blending the positive electrode active material NCM with a material has a voltage range of 2.75 - 4.2V. At a charge-discharge current of 1.0C / 1.0C, the capacity retention rate after 100 cycles is 97.58 - 97.71%, and the capacity retention rate after 200 cycles is 89.31 - 89.97%; Li4ZrF 8-2X O X The negative electrode sheet prepared by blending the negative electrode active material with a material has a voltage range of 2.75 - 4.2V. At a charge-discharge current of 1.0C / 1.0C, the capacity retention rate after 100 cycles is 97.34 - 97.74%, and the capacity retention rate after 200 cycles is 89.35 - 89.67%.

[0149] The above are only the preferred embodiments of the present disclosure. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present disclosure, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present disclosure. Industrial Applicability

[0150] The present disclosure provides a lithium-ion battery material, the structural formula of which is Li4ZrF 8-2X O X , 0 < X ≤ 0.15. The present disclosure conducts oxygen doping on the Li4ZrF8 material through zirconium-containing oxides, and the composition of the doped material is: Li4ZrF 8-2X O X ; By conducting oxygen doping at the F site, a significant increase in the ionic conductivity of the Li4ZrF8 material is achieved. In addition, the preparation method of the lithium-ion battery material is simple and easy to operate.

[0151] The present disclosure also provides a solid electrolyte material for solid-liquid mixing. When the Li4ZrF[[ID=2|4]] 8-2X O X material is applied to a lithium-ion battery, it is in full contact with the electrolyte. There is a trace amount of water (≤50 ppm) in the current commercial electrolyte. Since the electronegativity of fluorine element is much greater than that of hydrogen and oxygen elements, the fluoride bond formed with metal ions is extremely stable and not easily broken. Therefore, it is very difficult for fluoride crystals to generate free metal ions and fluoride ions on the surface, and thus it is impossible to react with water molecules to form hydroxyl groups. The present disclosure changes the surface state of the Li4ZrF 8-2X O X material by conducting oxygen doping at the F site. When in full contact with the electrolyte, the Li4ZrF[[ID=|32]] 8-2X O X material can react with the trace amount of water (≤50 ppm) in the electrolyte, generating hydroxyl groups on the surface of part of the Li4ZrF 8-2X O X material, forming Li4ZrF 8-2X O X ·(OH)y , which is beneficial to eliminate moisture in the electrolyte and effectively reduce the hydrolysis side reaction of LiPF6.

Claims

1. A lithium ion battery material, characterized in that: Its structural formula is Li4ZrF 8-2X O X , 0 <X≤0.15。 2. A method for preparing the lithium ion battery material according to claim 1, characterized in that: The following steps are involved: The zirconium source, the lithium source and the fluorine-containing acid solution are mixed, and filtered after the reaction to obtain a precursor; ball-milling the precursor and the zirconium-containing oxide in a medium to obtain a slurry; The slurry is dried and sintered to obtain a lithium ion battery material having the following general formula: Li4ZrF 8-2X The X ,0 <X≤0.15。 3. The preparation method according to claim 2, characterized in that: The zirconium source is zirconium carbonate; the lithium source is selected from lithium carbonate and / or lithium hydroxide.

4. The preparation method according to claim 2, characterized in that: The fluorine-containing acid solution is selected from hydrofluoric acid.

5. The preparation method according to claim 2, characterized in that: The zirconium-containing oxide is selected from one or more of zirconium oxide, lithium zirconate and zirconium hydroxide.

6. The preparation method according to claim 2, characterized in that: The medium is selected from one or more of ethanol, isopropanol, n-butanol, n-hexane, N-methylpyrrolidone, acetonitrile, dimethylformamide and dimethyl sulfoxide.

7. The preparation method according to claim 2, characterized in that: The sintering temperature is 400-800° C., and the sintering time is 12-24 hours.

8. The lithium-ion battery material according to claim 1 or the lithium-ion battery material prepared by the preparation method according to any one of claims 2 to 7 is used as a solid electrolyte in positive electrode coating materials, electrolyte additives, positive electrode plate additives, negative electrode plate additives or diaphragm coating materials.

9. A coating process for a positive electrode material, characterized in that: The following steps are involved: The lithium-ion battery material of claim 1 is used as a solid electrolyte, and the lithium-ion battery material Li4ZrF 8-2X O X It is made by coating the surface of the positive electrode material and then sintering.

10. The coating process of the positive electrode material according to claim 9, characterized in that: The sintering temperature is 300-600° C., and the sintering time is 5-10 hours.

11. The coating process of the positive electrode material according to claim 9, characterized in that: The rotation speed of the coating equipment is 10 to 550 rpm, and the coating time is 1 to 3 hours.

12. A solid electrolyte material for solid-liquid mixing, characterized in that: The lithium ion battery material Li4ZrF as claimed in claim 1 8-2X O X and electrolyte.

13. The coating process of the positive electrode material according to claim 12, characterized in that: The electrolyte includes LiPF6.

14. Use of a solid electrolyte material for solid-liquid mixing, characterized in that: The solid-liquid mixing solid electrolyte material according to claim 7 is applied to energy storage systems of lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, aluminum-ion batteries and fuel cells.

15. A battery, characterized in that: The invention comprises a pole piece and an electrolyte, wherein the pole piece comprises an active substance and the lithium ion battery material according to claim 1 or the lithium ion battery material prepared by the preparation method according to any one of claims 2 to 7 mixed in the active substance.

16. The battery according to claim 15, characterized in that The electrolyte includes LiPF6.

17. A battery, characterized in that: including coating of the diaphragm and the electrolyte; The coated separator comprises a base film and the lithium ion battery material according to claim 1 or the lithium ion battery material prepared by the preparation method according to any one of claims 2 to 7, which is coated on the surface of the base film.

18. The battery according to claim 17, characterized in that The electrolyte includes LiPF6.

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