Lithium metal powder, lithium metal negative electrode, lithium-ion battery and preparation method therefor

Abstract

A preparation method for a lithium metal powder, a product thereof, a prepared lithium metal negative electrode, and a finally assembled liquid electrolyte lithium-ion battery and solid electrolyte lithium-ion battery. The preparation method for a lithium metal powder comprises: mixing a lithium metal raw material with a polymer additive in an inert gas atmosphere, and then subjecting the mixture to freezing ball milling. The polymer additive does not react with the lithium metal raw material, and the Rockwell hardness of the polymer additive is 70-110. By means of the preparation method, a lithium metal powder having a uniform size can be prepared, the median particle size of which is not higher than 500 nm and minimally can reach 10 nm; and the preparation method has a low raw material cost and a simple and feasible process. A lithium-ion battery assembled by taking the lithium metal powder prepared by means of the method as a negative electrode active component has a high dendritic crystal growth critical current density and excellent electroplating / stripping cycle stability.

Description

Lithium metal powder, lithium metal negative electrode, lithium ion battery and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on February 6, 2024, with application number CN202410166669.1 and invention name “Lithium metal powder, lithium metal negative electrode, lithium ion battery and preparation method thereof”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of secondary batteries, and in particular to a lithium metal powder, a lithium metal negative electrode, a lithium ion battery and a preparation method thereof. Background Art

[0003] With the development of science and technology and the progress of human society, energy depletion and environmental pollution are becoming increasingly prominent. The development of new, efficient, and clean energy conversion, storage technologies, and energy utilization methods has become the key to solving these problems and achieving sustainable development of human society. Chemical power sources are an important technical approach to alleviate the energy, resource, and environmental crises and play an important role in the social energy system. Among the many chemical power sources, lithium-ion batteries, characterized by high energy efficiency and environmental friendliness, are gaining increasing attention. Applications such as new energy storage, electric vehicles, and smart grids have placed higher demands on the energy density, cycle life, power density, safety, cost, and environmental friendliness of lithium-ion batteries.

[0004] Lithium is very light (density 0.53g / cm 3 ), good ductility and conductivity. The theoretical specific capacity of metallic lithium is as high as 3860mAh / g, which is one of the materials with the highest theoretical specific capacity. + The standard electrode potential of lithium (Li) is -3.04V, the lowest of all redox couples. Therefore, metallic lithium is a promising battery anode material. However, its use as an anode material in lithium secondary batteries, lithium-sulfur batteries, and lithium-air batteries also presents significant challenges. Primarily, the formation of lithium dendrites during lithium deposition and dissolution can puncture the separator, leading to serious safety concerns.

[0005] The preparation of nanoscale metallic lithium powder with uniform particle size distribution can greatly reduce the local current density of metallic lithium negative electrode. At the same time, the high specific surface area brought by nano lithium powder can provide abundant nucleation sites for lithium deposition, reduce the nucleation overpotential during lithium deposition, thereby greatly increasing the critical current density of dendrite growth, improving the safety of lithium metal negative electrode, and promoting its commercial application.

[0006] However, the high reactivity, high viscosity and good ductility of metallic lithium itself make it difficult to synthesize metallic lithium powder using common methods such as mechanical crushing, and the resulting metallic lithium powder particles are relatively large. There are currently two commonly used methods for preparing lithium powder. One is to melt the metallic lithium and disperse it in an inert hydrocarbon oil. The second is to mix the metallic lithium raw material with an ionic liquid, and then heat and ultrasonically crush it, and then post-process it to obtain metallic lithium particles. The first two methods both have the following problems: First, the median particle size of the obtained lithium powder particles is relatively large, ranging from 500nm to 500μm, the specific surface area of ​​the lithium negative electrode is limited, and the critical current density of dendrite growth can only be increased to 10mA / cm 2 The German Association of the Automotive Industry requires that the current density of the negative electrode of the power battery can be between 40 and 80 mA / cm 2 The lithium powder obtained by the above methods obviously cannot meet the demand for commercialization of lithium metal negative electrodes because it operates at a low current density. Secondly, the operating temperature of both methods is relatively high, which needs to exceed the melting point of metallic lithium. Molten metallic lithium is highly corrosive and has strict requirements on equipment. Finally, the first method requires a high-boiling-point hydrocarbon oil to disperse the molten lithium droplets, and a low-boiling-point hydrocarbon oil to wash the lithium powder, resulting in severe environmental pollution, cumbersome preparation methods, and low preparation yields. The ionic liquid used in the second method is expensive, resulting in a high cost of this method.

[0007] A Chinese patent document with publication number CN108511713A discloses a method for preparing a submicron lithium negative electrode material. The method includes: mixing a metallic lithium raw material with an ionic liquid in an inert gas or dry air atmosphere to obtain a mixture; and subjecting the mixture to a cryogenic ball milling treatment in a freezing medium environment to obtain submicron metallic lithium particles dispersed in the ionic liquid.

[0008] This technical solution uses the principle that metallic lithium can become brittle under freezing conditions, making the originally sticky and ductile metallic lithium become more brittle, and crushing the larger lithium particles into smaller particles through mechanical ball milling. At this processing temperature, metallic lithium has low corrosion, but because ionic liquid is still used as a medium, not only is the production cost high, but because the ionic liquid used is dissolved in the liquid electrolyte, it will cause the structure of the metallic lithium particles to collapse during the electrochemical cycle, and at the same time cause the lithium particles to gradually increase in size during long-term electrochemical cycles; in addition, the median particle size of the metallic lithium particles obtained by this method is between 100 and 500 nm, which is still relatively large, and has limited effect on improving the specific surface area of ​​the lithium negative electrode and the critical current density of dendrite growth. Summary of the Invention

[0009] To address the aforementioned issues in the prior art, this application discloses a method for preparing lithium metal powder. This method produces uniform lithium metal powder with a median particle size no greater than 500 nm, and as low as 10 nm. This method features low raw material costs and a simple, easy-to-implement process. Lithium-ion batteries assembled using this prepared lithium metal powder as the negative electrode active component exhibit a high critical current density for dendrite growth and excellent plating / stripping cycle stability.

[0010] The specific technical solutions are as follows:

[0011] A method for preparing lithium metal powder, comprising:

[0012] Under an inert gas atmosphere, lithium metal raw materials and polymer additives are mixed and then cryo-ball milled;

[0013] The polymer additive does not react with the lithium metal raw material, and the Rockwell hardness of the polymer additive is 70-110.

[0014] This application discloses a simple preparation process that eliminates the need for expensive ionic liquids, which can affect electrochemical cycle stability. Instead, the process uses a polymer as an additive, providing both a grinding aid and a coating, significantly reducing the particle size of lithium metal. Furthermore, the polymer used in this application must be non-reactive with lithium metal and have a Rockwell hardness of 70 to 110, offering a wide range of options and broad applicability. Furthermore, no additional pretreatment of the polymer or lithium metal is required, effectively simplifying the preparation process.

[0015] Preferably, the polymer additive is selected from one or more of polymethyl methacrylate (Rockwell hardness of 92, the same below), polypropylene (90), styrene-butadiene-styrene block copolymer (88), polyacrylonitrile-butadiene-styrene copolymer (105), polyamide 66 (89), polycarbonate (93), and polyamide 6 (82).

[0016] Experiments have shown that when the Rockwell hardness of the polymer additive is too high, such as polyoxymethylene (121), or too low, such as polyethylene (60) or polytetrafluoroethylene (25), lithium metal cannot be ground into powder.

[0017] The lithium metal raw material is lithium powder, flake, block or filament material.

[0018] The frozen ball milling is specifically:

[0019] The mixture of the lithium metal raw material and the polymer additive is pre-frozen in a freezing medium, and then subjected to alternating high-frequency / high-speed ball milling and low-frequency / low-speed ball milling until the ball milling process is completed;

[0020] The mass ratio of the lithium metal raw material to the polymer additive is 1:(0.5-2.0); preferably 1:(0.7-1.5); and more preferably 1:1. A too low polymer content is detrimental to the refinement of lithium particles, while a too high polymer content, due to the low electronic conductivity of the polymer, is detrimental to the electrochemical performance of the resulting nano-lithium powder as a negative electrode material for lithium-ion batteries.

[0021] The inert gas atmosphere is selected from nitrogen atmosphere, helium atmosphere, argon atmosphere and the like.

[0022] The freezing medium is selected from one or more of liquid nitrogen, liquid helium, and liquid argon;

[0023] The temperature of the freezing ball mill is -270 to -100°C, preferably -200 to -150°C.

[0024] The pre-freezing time is 10 to 60 minutes;

[0025] When the freezing ball mill is selected from the vibration ball mill, the frequency of the high-frequency ball milling is 15 to 25 Hz, and the time of the high-frequency ball milling is 2 to 15 minutes; the frequency of the low-frequency ball milling is 1 to 10 Hz, and the time of the low-frequency ball milling is 1 to 10 minutes;

[0026] When the frozen ball mill is selected from the planetary ball mill, the rotation speed of the high-speed ball mill is 250-600 rpm, and the high-speed ball milling time is 5-60 minutes; the rotation speed of the low-speed ball mill is 30-250 rpm, and the low-speed ball milling time is 1-20 minutes;

[0027] The total time of ball milling treatment is 30 to 90 min;

[0028] The ball-to-material ratio is (10-100):1; the preferred ball-to-material ratio is (20-100):1; and more preferably 60:1.

[0029] After the above-mentioned freezing ball milling, the metallic lithium can be ground into lithium metal powder with a median particle size of ≤500 nm.

[0030] Preferably, when pre-freezing for 20 minutes, followed by alternating freezing ball milling for 60 minutes at a high frequency of 20 Hz and a low frequency of 5 Hz, and the ball-to-material ratio is controlled to 60:1, the metallic lithium can be ground into lithium metal powder with a median particle size of 100 nm.

[0031] Preferably, in this application, a step of ball milling at room temperature is added on the basis of frozen ball milling.

[0032] Experiments have found that by adjusting the ball milling process parameters at room temperature and screening the materials used in the ball mill, the median particle size of lithium metal powder can be significantly reduced, down to as low as 10nm.

[0033] Preferably, the ball milling at room temperature is selected from planetary ball milling, with a rotation speed of 100-400 rpm, a time of 3-30 hours, and a ball-to-material ratio of (50-200):1;

[0034] The ball milling jar and the grinding balls of the planetary ball mill are both made of agate.

[0035] Experiments have found that the material of the planetary ball mill, the ball mill speed, the ball mill time, the ball-to-material ratio and the grinding ball ratio will affect the particle size of the lithium metal powder prepared subsequently, thereby affecting the electrochemical properties of the lithium metal powder.

[0036] Regarding the material of the ball mill, among the common materials of stainless steel, tungsten carbide, zirconium oxide, and agate, stainless steel, tungsten carbide, and zirconium oxide will all bond with lithium. At this time, the energy of ball milling will cause the lithium to continue to bond to the ball mill beads, thereby making the size of lithium larger and larger. Only by choosing agate materials that do not bond with lithium, that is, agate ball mills and agate ball mills, can the energy of ball milling be used to further refine the particle size of lithium metal powder. Under the optimal ball milling process parameters, it is impossible to prepare lithium metal powder with a median particle size of 10nm using ball mills or ball mill beads made of stainless steel, tungsten carbide, or zirconium oxide.

[0037] Regarding the pellet to material ratio, the preferred pellet to material ratio is (50-150):1, and more preferably 150:1. As the pellet to material ratio is optimized, the median particle size of the lithium metal powder is more reduced.

[0038] Regarding the ratio of grinding balls, experiments have found that in the preparation method of the present application, a combination of large balls (with a diameter of 8 to 14 mm) with a mass ratio of 50 to 75%, medium balls (with a diameter of 1.5 to 6.0 mm) with a mass ratio of 20 to 40%, and the remainder being small balls (with a diameter of 0.5 to 1.5 mm) is more conducive to obtaining lithium metal powder with a median particle size of 10 nm.

[0039] Preferably, the rotation speed is 200-400 rpm, and the time is 3-20 h; more preferably, the ball milling is performed at 400 rpm for 6 h.

[0040] By adding a step of ball milling at room temperature on the basis of frozen ball milling, the median particle size of lithium metal powder can be controlled below 100nm, and can be as low as 10nm.

[0041] Further experiments found that if the polymer additive used in the first step of cryo-ball milling was replaced with ionic liquid, even if the room temperature ball milling process was optimized, lithium metal powder with a median particle size of 10nm could not be produced.

[0042] Preferably, an inert solvent that does not react with lithium or polymer is added to the room temperature ball milling process, specifically selected from n-hexane, cyclohexane, n-heptane, n-octane, benzene, etc. Experiments have found that the addition of an inert solvent can further increase the yield of the prepared lithium metal powder.

[0043] The present application also discloses a lithium metal negative electrode, comprising a current collector and a negative electrode active material layer deposited on the current collector, wherein the negative electrode active material layer comprises the lithium metal powder.

[0044] The present application also discloses a liquid lithium-ion battery, comprising a positive electrode, a negative electrode and an electrolyte;

[0045] The negative electrode adopts the above-mentioned lithium metal negative electrode, and the specific preparation process includes:

[0046] The lithium metal powder is cold pressed onto a current collector.

[0047] In this application, there are no special requirements for the current collector, and common types in the field are used, such as foam copper, foam aluminum, foam nickel, etc.

[0048] The cold pressing is performed at a pressure of 1 MPa to 1 GPa, more preferably, at a pressure of 100 to 500 MPa.

[0049] The positive electrode is made of common raw materials in the field, such as lithium-rich manganese-based positive electrode materials, layered oxide positive electrode materials, spinel structure positive electrode materials, and polyanion positive electrode materials.

[0050] The electrolyte includes a lithium salt and a non-aqueous solvent;

[0051] The lithium salt uses common raw materials in this field, such as lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium fluorohydroxysulfonate (LiC(SO2CF3)3), etc.; the non-aqueous solvent also uses common raw materials in this field, such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VC), etc.

[0052] Preferably, the electrolyte further includes an electrolyte additive;

[0053] The electrolyte additive is selected from one or more of fluoroethylene carbonate (FEC), phthalocyanine, phthalocyanine metal complex, I2 element, triethylsulfur iodide, 2,2,6,6-tetramethylpiperidinium oxide (TEMPO), and 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ).

[0054] The phthalocyanine metal complex is selected from one or more of copper phthalocyanine, nickel phthalocyanine, cobalt phthalocyanine, manganese phthalocyanine, zinc phthalocyanine and iron phthalocyanine.

[0055] Preferably, the mass fraction of the electrolyte additive is 0.01 to 10.00%, preferably 0.03 to 3.00%, and more preferably 0.1 to 1.0%.

[0056] Experiments have found that adding the above-mentioned electrolyte additives can further improve the critical current density of dendrite growth and the electroplating / stripping cycle stability of the assembled liquid lithium-ion battery.

[0057] More preferably, the electrolyte additive is selected from FEC, TEMPO, DBBQ, and phthalocyanine metal complexes.

[0058] More preferably, the electrolyte additive is selected from copper phthalocyanine.

[0059] The present application also discloses a solid-state lithium-ion battery, comprising a positive electrode, a negative electrode and a solid electrolyte;

[0060] The negative electrode is selected from the lithium metal negative electrode, and the specific preparation process includes:

[0061] The raw materials including the lithium metal powder, the solid electrolyte and the conductive agent are mixed evenly, and the obtained mixture is cold-pressed into an electrode sheet.

[0062] The solid electrolyte is selected from solid electrolytes that are stable to lithium metal negative electrodes, preferably one or more of hydride and oxide solid electrolytes that do not react with metallic lithium; preferably a PEO-based electrolyte, a boron hydride-based solid electrolyte, a carbon boron hydride-based solid electrolyte, a perovskite-type solid electrolyte, a lithium superion conductor (LISICON)-type solid electrolyte, a sodium superion conductor (NASICON)-type solid electrolyte, a garnet-type solid electrolyte, a lithium phosphorus oxygen nitrogen (LiPON)-type solid electrolyte, etc.

[0063] In the present application, there is no special requirement for the type of conductive agent, and it can be selected from the commonly used types in the field, such as one or more of graphite, acetylene black, SuperP, carbon nanotubes, graphene, and Ketjen black.

[0064] The raw materials can be mixed by ball milling, preferably planetary ball milling, specifically:

[0065] The planetary ball milling speed is 100-500 rpm, the time is 1-12 hours, and the ball-to-material ratio is (10-500):1.

[0066] When lithium metal powder, solid electrolyte, and conductive agent are used as raw materials, the raw material composition includes the following, based on the total weight of the above raw materials being 100%:

[0067] Lithium metal powder 60-95%;

[0068] Solid electrolyte 1-30%;

[0069] Conductive agent 1-10%;

[0070] Preferably, the raw material composition includes:

[0071] Lithium metal powder 70-90%;

[0072] Solid electrolyte 1-20%;

[0073] Conductive agent 1-10%;

[0074] Most preferably, the mass ratio of lithium metal powder, solid electrolyte, and conductive agent is 85:10:5. The cold pressing is performed at a pressure of 1 MPa to 1 GPa, more preferably, at a pressure of 100 to 500 MPa.

[0075] The positive electrode adopts the common types of raw materials in this field, such as lithium-rich manganese-based positive electrode materials, layered oxide positive electrode materials, spinel structure positive electrode materials, and polyanion positive electrode materials; the solid electrolyte is selected from solid electrolytes that are stable to lithium metal negative electrodes, preferably one or more of hydrides and oxide solid electrolytes that do not react with metallic lithium; preferably PEO-based electrolytes, boron hydride-based solid electrolytes, carbon boron hydride-based solid electrolytes, perovskite-type solid electrolytes, lithium superion conductor (LISICON)-type solid electrolytes, sodium superion conductor (NASICON)-type solid electrolytes, garnet-type solid electrolytes, lithium phosphorus oxygen nitrogen (LiPON)-type solid electrolytes, etc.

[0076] Compared with the prior art, this application has the following advantages:

[0077] The present application discloses a method for preparing lithium metal powder, which uses a polymer as an additive and takes advantage of the low-temperature brittleness of metallic lithium. The polymer acts as a grinding aid to reduce the particle size. By subjecting the lithium metal raw material and the polymer to cryo-ball milling, the median particle size of the metallic lithium powder can be controlled to below 500nm, and the polymer is coated around the lithium particles. By adding a step of room-temperature ball milling after the cryo-ball milling, and by precisely controlling the ball milling process, a lithium metal powder with a median particle size of 10nm can be prepared. This size is the finest size of metallic lithium powder in the world to date, greatly improving the specific surface area of ​​the metallic lithium powder. The preparation method is simple, the raw materials used are widely available, the price is low, the production cost is low, the efficiency of preparing nano-lithium particles is high, the time is short, and it is fully suitable for industrial production requirements. Since it does not need to be heated to above the melting point of metallic lithium, it can reduce energy consumption while reducing the requirements for equipment. No special corrosion-resistant treatment is required for the equipment, and the safety of production is also improved.

[0078] The polymer coating layer can limit the growth of the nano lithium powder negative electrode during the charge and discharge process, so that it always maintains the nanoscale during the electrochemical cycle; at the same time, the polymer coating layer can inhibit the side reaction between the metal lithium powder and the liquid electrolyte or solid electrolyte, thereby improving the stability of the electrode-electrolyte interface. However, too high a polymer coating amount will reduce the electronic conductivity of the lithium powder material and also reduce the theoretical capacity of the nano lithium powder material, which is not conducive to improving its electrochemical performance as a lithium ion battery negative electrode. Therefore, the lithium metal negative electrode further prepared using the lithium metal powder of the present application as a raw material, and the liquid lithium ion battery and solid lithium ion battery further assembled, all have extremely high dendrite growth critical current density and excellent electroplating / stripping cycle stability. In addition, by further optimizing the electrolyte of the liquid lithium ion battery, the battery performance can be further improved. In the best case, the dendrite growth critical current density of the assembled liquid lithium ion battery is close to 200mA / cm 2 , far exceeding the 40-80mA / cm specified by the German Association of the Automotive Industry. 2 The current density requirement is met, and at the same time, it has a plating / stripping cycle stability of more than 8000h, and is expected to be industrially applied. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] FIG1 is a cryo-TEM image of the lithium metal powder prepared in Example 1;

[0080] FIG2 is a particle size distribution diagram of the lithium metal powder prepared in Example 1;

[0081] FIG3 is an XRD pattern of the lithium metal powder prepared in Example 1;

[0082] FIG4 is a diagram of the BET argon isothermal adsorption and desorption of the lithium metal powder prepared in Example 1;

[0083] FIG5 is a voltage-current curve of a symmetrical battery A of liquid electrolyte lithium metal powder assembled with lithium metal powder prepared in Example 1;

[0084] FIG6 is a voltage curve of a symmetrical battery A of liquid electrolyte lithium metal powder assembled with lithium metal powder prepared in Example 1;

[0085] FIG7 is a voltage-current curve of a symmetrical battery B of liquid electrolyte lithium metal powder assembled with lithium metal powder prepared in Example 1;

[0086] FIG8 is a voltage curve of a symmetrical cell B of a liquid electrolyte lithium metal powder assembled with the lithium metal powder prepared in Example 1;

[0087] FIG9 is a cycle performance curve of a full battery of liquid electrolyte lithium metal powder assembled with lithium metal powder prepared in Example 1 at a current density of 20 mA / g (0.1C);

[0088] FIG10 is a voltage-current curve of a solid electrolyte lithium metal powder symmetrical battery assembled with lithium metal powder prepared in Example 1;

[0089] FIG11 is a voltage curve of a solid electrolyte lithium metal powder symmetrical battery assembled with the lithium metal powder prepared in Example 1;

[0090] FIG12 is a cycling performance curve of a solid electrolyte lithium metal powder full cell A assembled with lithium metal powder prepared in Example 1 at a current density of 12 mA / g (0.1C);

[0091] FIG13 is a scanning electron microscope image of the product prepared in Comparative Example 1;

[0092] FIG14 is a BET argon isothermal adsorption and desorption diagram of the lithium sheet used in Comparative Example 7;

[0093] FIG15 is a voltage-current curve of the liquid electrolyte lithium sheet symmetrical battery A assembled in Comparative Example 7;

[0094] FIG16 is a voltage curve of the liquid electrolyte lithium sheet symmetrical battery A assembled in Comparative Example 7;

[0095] FIG17 is a voltage-current curve of a liquid electrolyte lithium sheet symmetrical battery B assembled in Comparative Example 7;

[0096] FIG18 is a voltage curve of a symmetrical liquid electrolyte lithium sheet battery B assembled in Comparative Example 7;

[0097] FIG19 is a cycle performance curve of a full battery of liquid electrolyte lithium metal powder assembled in Comparative Example 7 at a current density of 20 mA / g (0.1C);

[0098] FIG20 is a voltage-current curve of a solid electrolyte lithium sheet symmetrical battery assembled in Comparative Example 7;

[0099] FIG21 is a voltage curve of a solid electrolyte lithium sheet symmetrical battery assembled in Comparative Example 7;

[0100] Figure 22 is the cycle performance curve of the solid electrolyte lithium sheet full battery A assembled in Comparative Example 7 at a current density of 12 mA / g (0.1C). DETAILED DESCRIPTION

[0101] In order to further understand the present application, the present application is described in detail below with reference to the embodiments and drawings, but the present application is not limited to these embodiments. Non-essential improvements and adjustments made by technical personnel in this field under the core guiding ideology of the present application still fall within the scope of protection of the present application.

[0102] Example 1

[0103] In an argon-filled glove box, lithium flakes and polymethyl methacrylate (PMMA) were added to a cryo-mill at a mass ratio of 1:1. The mixture was pre-chilled for 20 minutes and then subjected to alternating cryo-milling at 20 Hz high-frequency and 5 Hz low-frequency conditions for 60 minutes. Each high-frequency milling cycle lasted 5 minutes, and each low-frequency milling cycle lasted 1.5 minutes, resulting in a ball-to-material ratio of 60:1. The resulting intermediate product was scraped out in an argon-filled glove box. The intermediate product was then placed in an agate mill at a ball-to-material ratio of 150:1. The agate milling balls used included 12 mm large balls (50% of the total ball mass, the same below), 6 mm medium balls (40% of the total ball mass), and 1 mm small balls (10% of the total ball mass). The mill was then subjected to planetary milling at 400 rpm for 6 hours. The resulting lithium metal powder was scraped out in an argon-filled glove box, resulting in an 80% powder yield.

[0104] Figure 1 is a cryo-TEM image of the lithium metal powder prepared in this example. The cryo-TEM image shows that the prepared lithium metal powder has a regular shape, generally spherical.

[0105] Figure 2 shows the particle size distribution of the lithium metal powder prepared in this example. The D50 median diameter of the powder is 10.03 nm.

[0106] FIG3 is an XRD pattern of the lithium metal powder prepared in this example. The XRD pattern contains characteristic peaks of metallic Li but does not contain impurity peaks of Li2O, indicating that lithium did not chemically react with the polymer during the cryo-ball milling and planetary ball milling processes.

[0107] FIG4 is a BET argon isothermal adsorption and desorption diagram of the lithium metal powder prepared in this embodiment. The specific surface area of ​​the lithium metal powder is 245.95 m 2 / g, is the specific surface area of ​​lithium sheet (0.33m 2 / g, more than 700 times that of Comparative Example 7).

[0108] Application Example 1: Assembling a Liquid Electrolyte Lithium Metal Powder Symmetrical Battery A

[0109] The lithium metal powder prepared in this example was pressed onto nickel foam at a pressure of 400 MPa, with one piece serving as an electrode and the other as a counter electrode. A mixed solution of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) containing 1 mol / L LiPF6 (volume ratio of 1:1:1) was used as the electrolyte, and Celgard-2400 was used as the separator to prepare a CR2025 button cell, which was recorded as a liquid electrolyte lithium metal powder symmetric cell A.

[0110] The critical current density of dendrite growth was tested using the Xinwei battery test system. The starting current density of lithium plating / stripping was 1 mA / cm 2 The lithium plating / stripping time was 10 min each. After each cycle, the current density was increased with a step size of 1 mA / cm 2 The current density corresponding to the voltage drop is the critical current density for dendrite growth. The plating / stripping cycle stability was tested using the Xinwei battery test system. The current density for lithium plating / stripping was 1 mA / cm 2 The lithium plating / stripping time was 1 hour each. When the voltage dropped, it was judged as unstable cycling.

[0111] Figure 5 shows the voltage-current curve of the symmetrical battery A with liquid electrolyte lithium metal powder assembled in this embodiment. As can be seen from the figure, the critical current density of dendrite growth of the symmetrical battery assembled with lithium metal powder prepared in this embodiment is 152 mA / cm 2 , is the critical current density of the symmetrical battery assembled with lithium sheets (5.79 mA / cm 2 , nearly 30 times that of Comparative Example 7).

[0112] Figure 6 shows the voltage curve of the symmetrical cell A assembled with a liquid electrolyte and lithium metal powder, prepared in this example. As can be seen from the figure, the symmetrical cell assembled with lithium metal powder prepared in this example has a cycling stability of 3744 hours, which is over 120 times the cycling stability of the symmetrical cell assembled with lithium sheets (30 hours, Comparative Example 7).

[0113] Application Example 2: Assembling Liquid Electrolyte Lithium Metal Powder Symmetrical Battery B

[0114] The lithium metal powder prepared in this example was pressed onto nickel foam at a pressure of 400 MPa, with one piece serving as an electrode and one serving as a counter electrode. A mixed solution of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) containing 1 mol / L LiPF6 (volume ratio of 1:1:1) was used as the electrolyte. 0.5% copper phthalocyanine was added to the electrolyte as an additive. Celgard-2400 was used as the separator to produce a CR2025 button cell, designated as liquid electrolyte lithium metal powder symmetric cell B. The test conditions for this liquid electrolyte lithium metal powder symmetric cell were the same as above.

[0115] Figure 7 shows the voltage-current curve of the symmetrical battery B with liquid electrolyte lithium metal powder assembled in this embodiment. As can be seen from the figure, the critical current density of dendrite growth of the symmetrical battery B assembled with lithium metal powder prepared in this embodiment is 194 mA / cm 2 .

[0116] Figure 8 shows the voltage curve of the symmetrical battery B assembled with liquid electrolyte lithium metal powder in this embodiment. As can be seen from the figure, the cycle stability of the symmetrical battery B assembled with lithium metal powder prepared in this embodiment exceeds 8000 hours.

[0117] Application Example 3: Assembling a Liquid Electrolyte Lithium Metal Powder Symmetric Battery C

[0118] The assembly of the symmetrical liquid electrolyte lithium metal powder cell was essentially the same as in Application Example 2, except that the additive was replaced with an equal mass of DBBQ. This CR2025 button cell was fabricated and designated as symmetrical liquid electrolyte lithium metal powder cell C. The testing conditions for this symmetrical liquid electrolyte lithium metal powder cell were the same as above.

[0119] The critical current density of dendrite growth of the symmetrical battery C was tested to be 160 mA / cm 2 .

[0120] Application Example 4: Assembling a Liquid Electrolyte Lithium Metal Powder Symmetrical Battery D

[0121] The assembly of the liquid electrolyte lithium metal powder symmetric cell was essentially the same as in Application Example 2, except that the additive was replaced with an equal mass of TEMPO. This CR2025 button cell was fabricated and designated as liquid electrolyte lithium metal powder symmetric cell D. The testing conditions for this liquid electrolyte lithium metal powder symmetric cell were the same as above.

[0122] The critical current density of dendrite growth of the symmetrical cell D was tested to be 170 mA / cm 2 .

[0123] Application Example 5: Assembling a Liquid Electrolyte Lithium Metal Powder Full Battery

[0124] The lithium metal powder prepared in this example was pressed onto nickel foam at a pressure of 400 MPa as the negative electrode. 0.33 Co 0.33 Mn 0.33 A lithium-rich manganese oxide containing 0.2% O2 was used as the positive electrode. A mixed solution of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) (volume ratio of 1:1:1) containing 1 mol / L LiPF6 was used as the electrolyte. Celgard-2400 was used as the separator to manufacture CR2025 button cells, which were recorded as liquid electrolyte lithium metal powder full cells.

[0125] The electrochemical performance of the battery was tested using a Xinwei battery testing system. The test voltage window was 2.0 to 4.8 V, and the battery was tested using constant current charge and discharge.

[0126] Figure 9 shows the cycling performance curve of a full-cell battery with liquid electrolyte lithium metal powder assembled in this example at a current density of 20 mA / g (0.1C). The initial discharge capacity is 263 mAh / g, and the material's capacity is very stable. After 150 cycles, the discharge capacity is 245 mAh / g, and the capacity retention rate is as high as 93%. This is much higher than the discharge capacity and capacity retention rate when the lithium sheet is used as the negative electrode (initial discharge capacity is 255 mAh / g, and after 150 cycles, the discharge capacity is 210 mAh / g, and the capacity retention rate is 82%, compared to Comparative Example 7).

[0127] Application Example 6: Assembling a solid electrolyte lithium metal powder symmetrical battery

[0128] The lithium metal powder, LiBH4-based solid electrolyte and vapor-grown carbon fiber (VGCF) conductive agent prepared in this example were added to a planetary ball mill in a mass ratio of 85:10:5. The mixture was milled at 200 rpm for 3 hours to mix thoroughly. The resulting powder was scraped out in an argon atmosphere glove box. The powder was pressed onto a current collector at 400 MPa as a negative electrode, with one piece as an electrode and one piece as a counter electrode. A solid-state mold battery was prepared using the LiBH4-based solid electrolyte as the electrolyte, which was recorded as a solid-state electrolyte lithium metal powder symmetric battery.

[0129] The critical current density of dendrite growth was tested using the Xinwei battery test system. The starting current density of lithium plating / stripping was 0.1 mA / cm 2 , the capacity of lithium plating / stripping is 0.3mA / cm 2 After each cycle, the current density was increased by 0.2 mA / cm 2The current density corresponding to the voltage drop is the critical current density for dendrite growth. The plating / stripping cycle stability was tested using the Xinwei battery test system. The current density for lithium plating / stripping was 0.1 mA / cm 2 The lithium plating / stripping time was 1 hour each. When the voltage dropped, it was judged as unstable cycling.

[0130] Figure 10 shows the voltage-current curve of the solid electrolyte lithium metal powder symmetrical battery assembled in this embodiment. The critical current density of dendrite growth is 32 mA / cm 2 , is a solid electrolyte lithium metal powder symmetrical battery assembled with lithium sheets with a critical current density (0.38mA / cm 2 , more than 80 times that of Comparative Example 7).

[0131] Figure 11 shows the voltage curve of a symmetrical cell using solid electrolyte lithium metal powder assembled in this example. The cycling stability exceeds 1800 hours, which is 180 times the cycling stability of a symmetrical cell using solid electrolyte lithium metal powder assembled using lithium sheets (10 hours, Comparative Example 7).

[0132] Application Example 7: Assembly of Solid-State Electrolyte Lithium Metal Powder Full Battery A

[0133] The lithium metal powder, LiBH4-based solid electrolyte, and VGCF conductive agent prepared in this example were added to a planetary ball mill at a mass ratio of 85:10:5. The mixture was thoroughly mixed by planetary ball milling at 200 rpm for 3 hours. The resulting powder was scraped out in an argon atmosphere glove box. This powder was pressed onto a current collector at 400 MPa as the negative electrode. A solid-state mold cell was fabricated using LiCoO2 as the positive electrode and a LiBH4-based solid electrolyte as the electrolyte. This is referred to as solid-state electrolyte lithium metal powder full cell A.

[0134] The electrochemical performance of the battery was tested using a Xinwei battery testing system. The test voltage window was 3.0-4.2V, and the battery was tested using constant current charge and discharge.

[0135] Figure 12 shows the cycling performance curve of a full-cell A assembled with a solid electrolyte lithium metal powder according to this embodiment at a current density of 12 mA / g (0.1C). The initial discharge capacity is 129 mAh / g, and the material's capacity is very stable. After 50 cycles, the discharge capacity is 123 mAh / g, with a capacity retention rate of 95%. This is much higher than the discharge capacity and capacity retention rate of a lithium sheet as the negative electrode (initial discharge capacity is 127 mAh / g, and after 50 cycles, the discharge capacity is 15 mAh / g, with a capacity retention rate of 12%, as in Comparative Example 7).

[0136] Application Example 8: Assembly of Solid-State Electrolyte Lithium Metal Powder Full Battery B

[0137] The lithium metal powder, LLZTO solid electrolyte, and VGCF conductive agent prepared in this example were added to a planetary ball mill at a mass ratio of 85:10:5. The mixture was thoroughly mixed by planetary ball milling at 200 rpm for 3 hours. The resulting powder was then scraped out in an argon atmosphere glove box. This powder was pressed onto a current collector at 400 MPa as the negative electrode. LiCoO2 was used as the positive electrode, and the LLZTO solid electrolyte was used as the electrolyte to produce a solid-state molded cell, designated as solid-state electrolyte lithium metal powder full cell B. The testing conditions for this solid-state electrolyte lithium metal powder full cell were the same as those in Application Example 7.

[0138] After testing, the first discharge capacity of the full battery B was 127mAh / g. The capacity of the material was very stable. After 20 cycles, the discharge capacity was 116mAh / g, and the capacity retention rate was as high as 91%.

[0139] Example 2

[0140] The preparation process of lithium metal powder is basically the same as that in Example 1, except that polymethyl methacrylate is replaced by polypropylene of equal mass.

[0141] Morphological characterization showed that the lithium metal powder prepared in this example had a regular, generally spherical shape, and a median particle size D50 of 10 nm.

[0142] Example 3

[0143] The preparation process of lithium metal powder is basically the same as that of Example 1, except that polymethyl methacrylate is replaced by styrene-butadiene-styrene block copolymer of equal mass.

[0144] Morphological characterization showed that the lithium metal powder prepared in this example had a regular, generally spherical shape, and a median particle size D50 of 10 nm.

[0145] Examples 1 to 3 verify the universal applicability of the present invention in which polymer is used as an additive to grind metallic lithium into small-sized lithium powder.

[0146] Example 4

[0147] In an argon-filled glove box, lithium flakes and polymethyl methacrylate (PMMA) were added to a cryo-mill at a mass ratio of 1:1. The mixture was pre-chilled for 20 minutes and then cryo-milled for 60 minutes at alternating frequencies of 20 Hz and 5 Hz. Each high-frequency milling cycle lasted 5 minutes, and each low-frequency milling cycle lasted 1.5 minutes, resulting in a ball-to-material ratio of 60:1. The resulting product was scraped out of the argon-filled glove box.

[0148] The morphology of the lithium metal powder prepared in this example is regular in shape and generally spherical. The median particle size D50 of the powder is 101.19 nm, and the specific surface area is 133.21 m 2 / g.

[0149] The dendrite growth critical current density of the assembled liquid electrolyte lithium metal powder symmetrical battery A was 88.43 mA / cm 2 , cycle stability exceeds 2000h.

[0150] Example 5

[0151] The preparation process is basically the same as that of Example 4, except that the ball-to-material ratio of the frozen ball mill is replaced with 10:1.

[0152] Morphological characterization showed that the lithium metal powder prepared in this example had a regular, generally spherical shape, and a median particle size D50 of 300 nm.

[0153] Example 6

[0154] The preparation process is basically the same as that of Example 4, except that the ball-to-material ratio of the frozen ball mill is replaced with 100:1.

[0155] Morphological characterization showed that the lithium metal powder prepared in this example had a regular, generally spherical shape, and a median particle size D50 of 200 nm.

[0156] Example 7

[0157] The preparation process is basically the same as that of Example 1, except that the ball-to-material ratio of the planetary ball mill is replaced with 50:1.

[0158] Morphological characterization showed that the lithium metal powder prepared in this example had a regular, generally spherical shape, but the median particle size D50 of the powder was 50 nm.

[0159] Example 8

[0160] The preparation process is basically the same as that of Example 1, except that the ball-to-material ratio of the planetary ball mill is replaced with 200:1.

[0161] Morphological characterization showed that the lithium metal powder prepared in this example had a regular, generally spherical shape, but the median particle size D50 of the powder was 80 nm.

[0162] Example 9

[0163] The preparation process is basically the same as that of Example 1, except that an inert solvent, n-hexane, is additionally added during the planetary ball milling, and the added amount is 80% of the volume of the ball milling jar.

[0164] According to tests, the median particle size D50 of the lithium metal powder prepared in this embodiment is 10 nm, and the yield is 99%.

[0165] Comparative Example 1

[0166] The preparation process of lithium metal powder is basically the same as that of Example 1, except that polymethyl methacrylate is replaced by homopolyoxymethylene of equal mass.

[0167] The experiment found that the lithium sheets could not be ground apart, and the lithium obtained was agglomerated lamellar lithium, as shown in the SEM image in Figure 13.

[0168] Comparative Example 2

[0169] The preparation process of lithium metal powder is basically the same as that of Example 1, except that polymethyl methacrylate is replaced by polyethylene of equal mass.

[0170] The experiment found that the lithium sheets could not be ground apart, and the lithium obtained was agglomerated lamellar lithium.

[0171] Comparative Example 3

[0172] The preparation process of lithium metal powder is basically the same as that of Example 1, except that polymethyl methacrylate is replaced by polytetrafluoroethylene of the same mass.

[0173] The experiment found that the lithium sheets could not be ground apart, and the lithium obtained was agglomerated lamellar lithium.

[0174] Comparative Example 4

[0175] The preparation process of lithium metal powder is basically the same as that of Example 1, except that polymethyl methacrylate is replaced with an equal mass of ionic liquid tributyl (methyl ether) phosphine (the ionic liquid needs to be pretreated by heating at 150° C. for 1 h).

[0176] The experiment found that the median particle size D50 of the lithium metal powder finally prepared in this comparative example was only 500 nm.

[0177] Comparative Example 5

[0178] The preparation process of lithium metal powder is basically the same as that of Example 1, with the only difference being that stainless steel ball milling jars and grinding balls are used in planetary ball milling.

[0179] The experiment found that lithium metal agglomerated and it was impossible to obtain fine lithium metal powder.

[0180] Comparative Example 6

[0181] The preparation process of lithium metal powder is basically the same as that of Example 1, except that the ball-to-material ratio is replaced with 300:1 during planetary ball milling.

[0182] The test found that the median particle size D50 of the lithium metal powder prepared in this comparative example was 150 nm. In addition, silicon dioxide impurities were introduced.

[0183] Comparative Example 7

[0184] Commercially available lithium sheets (manufacturer, brand, thickness) were directly used as electrodes. Liquid symmetrical batteries, liquid full batteries, solid-state symmetrical batteries, and solid-state full batteries were assembled according to the method in Example 1, and the performance of the above batteries was tested using the same method.

[0185] Figure 14 is a BET argon isothermal adsorption and desorption diagram of the lithium sheet used in this comparative example. The specific surface area of ​​the lithium sheet is only 0.33 m 2 / g. Significantly lower than that in Example 1 of the present application.

[0186] Figure 15 shows the voltage-current curve of the liquid electrolyte lithium sheet symmetrical battery A assembled in this comparative example. The critical current density of the lithium sheet is only 5.79 mA / cm 2 . It is significantly lower than that of Example 1 of the present application.

[0187] Figure 16 shows the voltage curve of the liquid electrolyte lithium sheet symmetrical battery A assembled in this comparative example. The cycling stability of the lithium sheet is only 30 hours, significantly lower than that of Example 1 of this application.

[0188] Figure 17 shows the voltage-current curve of the liquid electrolyte lithium sheet symmetrical battery B (0.5 wt% copper phthalocyanine was added to the electrolyte as an additive) assembled in this comparative example. The critical current density of the lithium sheet is only 11.57 mA / cm 2 . It is significantly lower than that of Example 1 of the present application.

[0189] Figure 18 shows the voltage curve of the liquid electrolyte lithium sheet symmetrical battery B assembled in this comparative example. The cycle stability of the lithium sheet is only 500 hours, which is significantly lower than that of Example 1 of this application.

[0190] Figure 19 shows the cycling performance curve of a full-cell lithium metal powder battery with a liquid electrolyte assembled in this comparative example at a current density of 20 mA / g (0.1C). When the lithium sheet is used as the negative electrode, the initial discharge capacity is 255 mAh / g, and after 150 cycles, the discharge capacity is 210 mAh / g, with a capacity retention rate of only 82%. This is significantly lower than that of Example 1 of this application.

[0191] Figure 20 shows the voltage-current curve of the solid electrolyte lithium sheet symmetrical battery assembled in this comparative example. The critical current density of the lithium sheet is only 0.38 mA / cm 2 . It is significantly lower than that of Example 1 of the present application.

[0192] Figure 21 shows the voltage curve of the solid electrolyte lithium sheet symmetrical battery assembled in this comparative example. The cycling stability of the lithium sheet is only 10 hours, significantly lower than that of Example 1 of this application.

[0193] Figure 22 shows the cycling performance curve of solid-state electrolyte lithium sheet full cell A assembled in this comparative example at a current density of 12 mA / g (0.1C). The initial discharge capacity of the lithium sheet as the negative electrode was 127 mAh / g, and after 50 cycles, the discharge capacity was 15 mAh / g, with a capacity retention rate of only 12%. This is significantly lower than that of Example 1 of this application.

[0194] The above description is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. The above application uses specific examples to illustrate the present application, which is only used to help understand the present application and is not intended to limit the present application. Those skilled in the art of the present application can also make several simple deductions, deformations, substitutions or combinations based on the concept of the present application. These deductions, deformations, substitutions or combinations also fall within the scope of the claims of the present application.

Claims

1. A method for preparing lithium metal powder, characterized in that: include: Under an inert gas atmosphere, lithium metal raw materials and polymer additives are mixed and then cryo-ball milled; The polymer additive does not react with the lithium metal raw material, and the Rockwell hardness of the polymer additive is 70-110.

2. The method for preparing lithium metal powder according to claim 1, wherein The mass ratio of the lithium metal raw material to the polymer additive is 1:(0.5-2.0).

3. The method for preparing lithium metal powder according to claim 1 or 2, characterized in that: The frozen ball milling is specifically: The mixture of the lithium metal raw material and the polymer additive is pre-frozen in a freezing medium, and then subjected to alternating high-frequency / high-speed ball milling and low-frequency / low-speed ball milling until the ball milling process is completed; The freezing medium is selected from one or more of liquid nitrogen, liquid helium and liquid argon; The pre-freezing time is 10 to 60 minutes; When the freezing ball mill is selected from the vibration ball mill, the frequency of the high-frequency ball milling is 15 to 25 Hz, and the time of the high-frequency ball milling is 2 to 15 minutes; the frequency of the low-frequency ball milling is 1 to 10 Hz, and the time of the low-frequency ball milling is 1 to 10 minutes; When the frozen ball mill is selected from the planetary ball mill, the rotation speed of the high-speed ball mill is 250-600 rpm, and the high-speed ball milling time is 5-60 minutes; the rotation speed of the low-speed ball mill is 30-250 rpm, and the low-speed ball milling time is 1-20 minutes; The total time of ball milling treatment is 30 to 90 min; The ball-to-material ratio is (10-100):

1.

4. The method for preparing lithium metal powder according to claim 3, wherein: When the pre-freezing time is 20 minutes, the ball milling is performed alternately at a high frequency of 20 Hz and a low frequency of 5 Hz for a total of 60 minutes, and the ball-to-material ratio is 60:1, the median particle size of the obtained lithium metal powder is 100 nm.

5. The method for preparing lithium metal powder according to claim 1, wherein The polymer additive is selected from one or more of polymethyl methacrylate, polypropylene, styrene-butadiene-styrene block copolymer, polyacrylonitrile-butadiene-styrene copolymer, polycarbonate, polyamide 66 and polyamide 6.

6. The method for preparing lithium metal powder according to claim 1, wherein: After the freezing ball milling, the method further includes subjecting the product after the freezing ball milling to ball milling at room temperature.

7. The method for preparing lithium metal powder according to claim 6, characterized in that: The ball mill at room temperature is selected from a planetary ball mill, with a rotation speed of 100-400 rpm, a time of 3-30 hours, and a ball-to-material ratio of (50-200):1; the ball mill jar and the grinding balls of the planetary ball mill are both made of agate.

8. The method for preparing lithium metal powder according to claim 7, characterized in that: The grinding balls used in the ball mill at room temperature include the following mass percentage composition: 50-75% large balls, 20-40% medium balls and the remainder small balls; the diameter of the large balls is 8-14 mm, the diameter of the medium balls is 1.5-6.0 mm, and the diameter of the small balls is 0.5-1.5 mm.

9. The method for preparing lithium metal powder according to claim 6, wherein: The ball milling process at room temperature further includes adding an inert solvent, which does not react with the lithium metal raw material or the polymer additive; the inert solvent includes one or more of n-hexane, cyclohexane, n-heptane, n-octane and benzene.

10. A lithium metal powder prepared according to the method according to any one of claims 1 to 9, characterized in that The median particle size of the lithium metal powder is ≤500 nm.

11. A lithium metal negative electrode comprising a current collector and a negative electrode active material layer deposited on the current collector, characterized in that: The negative electrode active material layer includes the lithium metal powder according to claim 10.

12. A liquid electrolyte lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, characterized in that: The negative electrode is selected from the lithium metal negative electrode according to claim 11; The electrolyte includes lithium salt and non-aqueous solvent.

13. The liquid electrolyte lithium ion battery according to claim 12, characterized in that: The electrolyte also includes an electrolyte additive; The electrolyte additive is selected from one or more of fluoroethylene carbonate, phthalocyanine, phthalocyanine metal complex, I2 element, triethyl iodide sulfur, 2,2,6,6-tetramethylpiperidinoxide, and 2,5-di-tert-butyl-1,4-benzoquinone.

14. The liquid electrolyte lithium ion battery according to claim 12 or 13, characterized in that: The mass fraction of the electrolyte additive is 0.01 to 10.00%.

15. The liquid electrolyte lithium ion battery according to claim 12, characterized in that: The negative electrode preparation process includes: cold pressing the lithium metal powder onto a current collector; The cold pressing pressure is 1 MPa to 1 GPa.

16. A solid electrolyte lithium ion battery comprising a positive electrode, a negative electrode and a solid electrolyte, characterized in that: The negative electrode is selected from the lithium metal negative electrode according to claim 11.

17. The solid electrolyte lithium ion battery according to claim 16, characterized in that: The negative electrode preparation process includes: uniformly mixing raw materials including lithium metal powder, solid electrolyte and conductive agent, and cold pressing the obtained mixture to form the negative electrode; The cold pressing pressure is 1 MPa to 1 GPa.

18. The solid electrolyte lithium ion battery according to claim 17, characterized in that The mixing method is ball milling; The ball mill is a planetary ball mill, specifically: the planetary ball mill speed is 100-500 rpm, the time is 1-12 hours, and the ball-to-material ratio is (10-500):

1.

19. The solid electrolyte lithium ion battery according to claim 16, characterized in that Taking the total weight of lithium metal powder, solid electrolyte and conductive agent as 100%, the raw material composition includes: lithium metal powder 60-95%; solid electrolyte 1-30%; conductive agent 1-10%.

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