Rare earth-based lithium alloy negative electrode material and preparation method and application thereof

Abstract

This invention discloses a rare-earth-based lithium alloy anode material, its preparation method, and its application. The preparation method includes the following steps: S1: mechanically mixing rare earth elements with an active material to obtain a rare-earth-active material mixture; S2: calcining the rare-earth-active material mixture obtained in step S1 at 500-1500℃ for 1-10 hours to obtain a rare-earth-based alloy material; S3: mechanically mixing lithium metal with the rare-earth-based alloy material obtained in step S2 to obtain a rare-earth-based lithium alloy material; wherein the molar ratio of rare earth elements, active material, and lithium metal is 1-50:1-99:1-99. This invention combines a high-temperature solid-state method with a mechanical mixing method to obtain a rare-earth-based lithium alloy material. When used as an anode in lithium batteries, it can suppress dendrite growth to a certain extent and improve the cycle stability of the battery.

Description

Technical Field

[0001] This invention relates to a rare earth-based lithium alloy anode material, its preparation method, and its application, belonging to the field of lithium battery technology. Background Technology

[0002] With the introduction of dual-carbon goals, my country is vigorously promoting the development of green and low-carbon industries such as wind / solar power generation and new energy vehicles. The storage and utilization of electrical energy is a crucial link, supporting the development of the new energy industry. Among various energy storage devices, lithium batteries have the longest cycle life and highest energy density, making them the most widely used.

[0003] Lithium-ion batteries typically consist of three parts: a negative electrode, an electrolyte, and a positive electrode. They store and release electrical energy through the movement of lithium ions between the electrodes. The properties of the negative electrode significantly impact the overall battery performance. For example, during the charging and discharging process, uncontrollable dendrite formation often occurs on the negative electrode side, reducing cycle life and potentially leading to short circuits and safety risks such as combustion and explosion. Furthermore, volume changes in the negative electrode material during charging and discharging, as well as side reactions with the electrolyte, increase internal resistance and reduce battery capacity. To address these issues, researchers often use lithium-based alloys as the negative electrode, which promotes uniform lithium-ion deposition. However, the volume changes caused by lithium insertion and extraction in lithium-based alloy negative electrodes are also significant.

[0004] This application is submitted in response to the above-mentioned issues. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a rare-earth-based lithium alloy anode material and apply it in lithium batteries, thus solving the problem of the need to optimize the stability of lithium battery anodes.

[0006] The first objective of this invention is to provide a method for preparing a rare-earth-based lithium alloy anode material, comprising the following steps:

[0007] S1: Mechanically mix rare earth elements with active materials to obtain a rare earth-active material mixture;

[0008] S2: Calcine the rare earth-active material mixture obtained in step S1 at 500-1500℃ for 1-10 hours to obtain rare earth-based alloy material;

[0009] S3: Mechanically mix lithium metal with the rare earth-based alloy material obtained in step S2 to obtain a rare earth-based lithium alloy material.

[0010] The molar ratio of rare earth, active material, and lithium metal is 1-50:1-99:1-99.

[0011] Preferably, the rare earth elements include one or more of scandium, yttrium, lanthanum, cerium, spectroscopy, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

[0012] Preferably, the lithium metal is one or more of lithium blocks, lithium sheets, and lithium powder.

[0013] Preferably, the active material includes alloy-type negative electrodes indium, tin, aluminum, magnesium, silicon, germanium, antimony, bismuth, and one or more of carbon-based negative electrodes graphite, graphene, hard carbon, and soft carbon.

[0014] Preferably, the mechanical mixing in step S1 is performed by repeated cold pressing, manual grinding, or mechanical ball milling. The repeated cold pressing method involves repeatedly cold pressing rare earth elements and active materials into sheets at a pressure of 2-4 tons, with 5-20 repetitions. The manual grinding method involves mixing rare earth elements and active materials in a mortar for 5-30 minutes. The mechanical ball milling method involves mixing rare earth elements and active materials using a ball mill at a speed of 200-500 r / min for 1-10 hours.

[0015] Using the above technical solutions, for sheet-like or block-like active materials with good ductility, such as indium and tin, it is preferable to use repeated cold pressing to mix rare earth and active materials; for powdered active materials, it is preferable to use manual grinding or mechanical ball milling to mix rare earth and active materials.

[0016] Preferably, in step S2, the rare earth-active material mixture is calcined at 700-1000℃ for 4-6 hours.

[0017] Using the above technical solution, the rare earth, active material and lithium metal used in this invention are in the form of powder, flake or block, wherein the particle size of the powdered rare earth, active material and lithium metal is 10-10000 mesh, preferably 100-1000 mesh.

[0018] In step S3, the lithium metal and rare earth-based alloy material are mechanically mixed, including repeated cold pressing, manual grinding, or mechanical ball milling. For lithium sheets or blocks, repeated cold pressing is preferred. For lithium powder, manual grinding or mechanical ball milling is preferred.

[0019] The second objective of this invention is to provide a rare earth-based lithium alloy anode material prepared by the above method, wherein the rare earth-based lithium alloy anode material is in the form of a block or powder.

[0020] A third objective of this invention is to provide the application of the above-mentioned rare earth-based lithium alloy anode material in lithium batteries, including an anode, an electrolyte, and a cathode, wherein the anode is a rare earth-based lithium alloy anode material.

[0021] Preferably, the negative electrode is one or both of bulk rare earth-based alloy materials and powdered rare earth-based alloy materials.

[0022] Preferably, the electrolyte includes one or two of liquid electrolytes and solid electrolytes; the liquid electrolyte includes one or two of carbonate electrolytes and ether electrolytes; and the solid electrolyte includes one or more of polymer electrolytes, oxide electrolytes, sulfide electrolytes, and halide electrolytes.

[0023] Preferably, the positive electrode comprises 10%-90% positive electrode active material, 0-70% solid electrolyte, 0-20% carbon material, and 0-10% binder. The positive electrode active material comprises one or more combinations of lithium-containing positive electrode or lithium-free positive electrode. The carbon material comprises one or more combinations of acetylene black, Ketjen black, carbon nanotubes, graphite, graphene, soft carbon, hard carbon, activated carbon, and carbon fiber.

[0024] Preferably, the adhesive is one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyacrylonitrile (PAN), polyethylene oxide (PEO), and polyacrylate.

[0025] Using the above technical solution, the bulk rare earth-based alloy material needs to be cold-pressed into sheets at a pressure of 1-5t, preferably 3-4t, with a thickness of 100-200μm. The powdered rare earth-based alloy material needs to be mixed with a binder and then rolled or pressed to form a rare earth-based alloy film with a mass of 10-20mg / cm³. 2 Thickness 100-200μm.

[0026] The beneficial effects of this invention are:

[0027] (1) The present invention combines high-temperature solid-state method and mechanical mixing method to obtain rare earth-based lithium alloy material, which can be used as negative electrode in lithium battery to suppress dendrite growth to a certain extent and improve the cycle stability of battery.

[0028] (2) Rare earth elements are large in size and have low electronegativity, which can stabilize the structure of the anode material, limit the volume change during charging and discharging, and guide the uniform deposition of lithium ions. They have great potential for application in lithium-based alloy anodes. Attached Figure Description

[0029] Figure 1 This refers to the charge-discharge cycle performance of the lithium battery in Embodiment 1 of the present invention, wherein the negative electrode is a cerium-indium-lithium alloy.

[0030] Figure 2This describes the charge-discharge cycle performance of the lithium battery in Comparative Example 1 of the present invention, wherein the negative electrode is an indium-lithium alloy.

[0031] Figure 3 This refers to the charge-discharge cycle performance of the lithium symmetric battery in Embodiment 2 of the present invention, wherein the electrode is a cerium-indium-lithium alloy.

[0032] Figure 4 This describes the charge-discharge cycle performance of the lithium symmetric battery in Comparative Example 2 of the present invention, wherein the electrode is a magnesium-indium-lithium alloy.

[0033] Figure 5 This is a SEM image of the lanthanum-tin-lithium alloy in Example 3 of this invention.

[0034] Figure 6 This is a SEM image of the tin-lithium alloy in Comparative Example 3 of this invention.

[0035] Figure 7 This is the electrochemical impedance spectroscopy of the lithium symmetric battery in Example 4 of the present invention, wherein the electrode is a lanthanum-tin-lithium alloy.

[0036] Figure 8 This is the electrochemical impedance spectroscopy of the lithium symmetric battery in Comparative Example 4 of this invention, wherein the electrode is a zinc-tin-lithium alloy.

[0037] Figure 9 This is the charge-discharge curve of the lithium battery in Embodiment 5 of the present invention, wherein the electrode is a yttrium-aluminum-lithium alloy.

[0038] Figure 10 This is the charge-discharge curve of the lithium battery in Comparative Example 5 of the present invention, wherein the electrode is an aluminum-lithium alloy.

[0039] Figure 11 This is the electrochemical impedance spectroscopy of the lithium symmetric battery in Example 6 of the present invention, wherein the electrode is a yttrium-aluminum-lithium alloy.

[0040] Figure 12 This is the electrochemical impedance spectroscopy of the lithium symmetric battery in Comparative Example 6 of the present invention, wherein the electrode is a tin-aluminum-lithium alloy.

[0041] Figure 13 This is the electrochemical impedance spectroscopy of the lithium symmetric battery after cycling in Example 7 of the present invention, wherein the electrode is a praseodymium-silicon-lithium alloy.

[0042] Figure 14 This is the electrochemical impedance spectroscopy of the lithium symmetric battery after cycling in Comparative Example 7 of this invention, wherein the electrode is a silicon-lithium alloy.

[0043] Figure 15 This refers to the charge-discharge cycle performance of the lithium battery in Embodiment 8 of the present invention, wherein the electrode is a praseodymium-silicon-lithium alloy.

[0044] Figure 16 This is the charge-discharge cycle performance of the lithium battery in Comparative Example 8 of the present invention, wherein the electrode is a praseodymium-silicon-lithium alloy.

[0045] Figure 17 This refers to the cycle performance of the lithium battery in Embodiment 9 of the present invention, wherein the electrode is a yttrium-silicon-graphite-lithium alloy.

[0046] Figure 18 This describes the cycle performance of the lithium battery in Comparative Example 9 of the present invention, wherein the electrode is a silicon-graphite-lithium alloy.

[0047] Figure 19 This refers to the charge-discharge cycle performance of the lithium battery in Embodiment 10 of the present invention, wherein the electrode is a yttrium-silicon-graphite-lithium alloy.

[0048] Figure 20 This describes the charge-discharge cycle performance of the lithium battery in Comparative Example 10 of the present invention, wherein the electrode is a tin-silicon-graphite-lithium alloy. Detailed Implementation

[0049] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0050] Example 1

[0051] (1) The preparation method of cerium-indium-lithium alloy material is as follows:

[0052] Raw materials: cerium blocks, indium sheets and lithium metal sheets, with a molar ratio of 7:65:28.

[0053] First, cerium blocks and indium sheets are repeatedly cold-pressed into a mixed metal block. Then, the mixed metal block is placed in a graphite crucible and calcined in an argon atmosphere for 5 hours at a calcination temperature of 700℃ to obtain a cerium-indium alloy block. Subsequently, lithium sheets are repeatedly cold-pressed and mixed with the cerium-indium alloy block to obtain a cerium-indium-lithium alloy.

[0054] (2) The specific preparation method of the lithium symmetric battery with cerium-indium-lithium alloy material as electrode is as follows:

[0055] The electrolyte is a halide solid electrolyte (Li3YBr6); the electrode is a cerium-indium-lithium alloy sheet after cold pressing, with a pressure of 4t and a thickness of 100-200μm.

[0056] 100 mg of Li3YBr6 powder was weighed and placed in a circular mold. A pressure of 2t was applied to obtain an electrolyte sheet. Cerium-indium-lithium alloy sheets were added to both sides of the electrolyte sheet, and a pressure of 4t was applied to obtain a lithium symmetric battery. The inner diameter of the circular mold was 10 mm, and the diameter of the cerium-indium-lithium alloy sheets was 10 mm.

[0057] (3) The specific preparation method of the lithium battery with cerium-indium-lithium alloy material as negative electrode is as follows:

[0058] The electrolyte is a halide solid electrolyte (Li3YBr6); the negative electrode is a cerium-indium-lithium alloy sheet after cold pressing, with a pressure of 4t and a thickness of 100-200μm; the positive electrode is a mixture of lithium titanate, Li3YBr6, and Ketjen black in a mass ratio of 2:7:1.

[0059] 100 mg of Li3YBr6 powder was weighed and placed in a circular mold. A pressure of 2 tons was applied to obtain an electrolyte sheet. 10 mg of positive electrode was added to one side of the electrolyte sheet, and a pressure of 4 tons was applied. A cerium-indium-lithium alloy sheet was added to the other side, and a pressure of 1 tons was applied to obtain a lithium battery. The inner diameter of the circular mold was 10 mm, and the diameter of the cerium-indium-lithium alloy sheet was 10 mm.

[0060] Comparative Example 1

[0061] (1) The preparation method of indium-lithium alloy material differs from that in Example 1 in that: raw materials: indium sheet and lithium metal sheet, with a molar ratio of 7:3. The indium-lithium alloy can be obtained by repeatedly cold pressing and mixing the lithium sheet and the indium sheet.

[0062] (2) The specific preparation method of the lithium symmetric battery with indium-lithium alloy material as electrode material differs from that in Example 1 in that:

[0063] Replace the cerium-indium-lithium alloy with an indium-lithium alloy.

[0064] (3) The specific preparation method of the lithium battery with indium-lithium alloy material as negative electrode differs from that in Example 1 in that:

[0065] Replace the cerium-indium-lithium alloy with an indium-lithium alloy.

[0066] Figure 1 The charge-discharge curve of the lithium battery in Example 1 (negative electrode: cerium-indium-lithium alloy). Figure 2 The charge-discharge curves of the lithium battery in Comparative Example 1 (negative electrode: indium-lithium alloy) are shown. Figure 2 compared to, Figure 1 The charge-discharge curves in the cerium-indium-lithium alloy anode exhibit larger capacity, smaller voltage polarization, and smaller capacity decay, indicating that a more stable lithium insertion / extraction process can be achieved.

[0067] Example 2

[0068] (1) The preparation method of cerium-indium-lithium alloy material differs from that in Example 1 in that cerium blocks are replaced with cerium powder and indium sheets are replaced with indium powder in the raw materials.

[0069] (2) The lithium symmetric battery with cerium-indium-lithium alloy material as electrode is prepared differently from that in Example 1 in that the electrolyte is a halide solid electrolyte (Li3YCl6).

[0070] (3) The lithium battery with cerium-indium-lithium alloy material as negative electrode is prepared differently from Example 1 in that the electrolyte is a halide solid electrolyte (Li3YCl6), and the positive electrode is a mixture of lithium manganese oxide, Li3YCl6 and Ketjen black in a mass ratio of 7:2:1.

[0071] Comparative Example 2

[0072] (1) The preparation method of magnesium-indium-lithium alloy material differs from that in Example 2 in that the raw materials are magnesium powder, indium sheet and lithium metal sheet, with a molar ratio of 0.07:0.65:0.28. The magnesium powder and indium sheet are repeatedly cold-pressed into a mixed metal block.

[0073] (2) The preparation method of the lithium symmetric battery with magnesium-indium-lithium alloy electrode is different from that of Example 2 in that the cerium-indium-lithium alloy is replaced with magnesium-indium-lithium alloy.

[0074] (3) The preparation method of the lithium battery with magnesium-indium-lithium alloy material as negative electrode is different from that of Example 2: the cerium-indium-lithium alloy is replaced with magnesium-indium-lithium alloy.

[0075] Figure 3 The charge-discharge curves of the lithium symmetric battery in Example 2 (negative electrode: cerium-indium-lithium alloy). Figure 4 The charge-discharge curves of the lithium-ion symmetric battery in Comparative Example 2 (negative electrode: magnesium-indium-lithium alloy) are shown. Figure 4 compared to, Figure 3 The charge-discharge curves are more stable, indicating that the cerium-indium-lithium alloy anode can achieve more stable electrode / electrolyte interface contact during the charge-discharge process.

[0076] Example 3

[0077] (1) The preparation method of lanthanum-tin-lithium alloy material differs from that in Example 1 in that the raw materials are lanthanum blocks, tin sheets and lithium metal sheets, with a molar ratio of 1:11:8.

[0078] (2) The preparation method of the lithium symmetric battery using lanthanum-tin-lithium alloy material as electrode material differs from that in Example 1 in that the electrolyte is a sulfide solid electrolyte (Li7P3S). 11 Its mass is 80mg.

[0079] (3) The lithium battery with lanthanum-tin-lithium alloy material as negative electrode is prepared differently from that in Example 1 in that the electrolyte is a sulfide solid electrolyte (Li7P3S). 11The positive electrode is lithium cobalt oxide, Li7P3S 11 A mixture of 7:2.8:0.2 by mass.

[0080] Comparative Example 3

[0081] (1) The preparation method of tin-lithium alloy material differs from that in Example 3 in that the raw materials are tin sheet and lithium metal sheet with a molar ratio of 6:4. The tin-lithium alloy can be obtained by repeatedly cold pressing and mixing the lithium sheet and the tin sheet.

[0082] (2) The preparation method of the lithium symmetric battery with tin-lithium alloy material as electrode is different from that in Example 1: the lanthanum-tin-lithium alloy is replaced with tin-lithium alloy.

[0083] (3) The preparation method of the lithium battery with tin-lithium alloy material as negative electrode is different from that of Example 1 in that the lanthanum-tin-lithium alloy is replaced with tin-lithium alloy.

[0084] Figure 5 The image shows a SEM image of the lanthanum-tin-lithium alloy in Example 3. Figure 6 This is a SEM image of the tin-lithium alloy in Comparative Example 3. (Compared to...) Figure 6 Compared to the smooth morphology, Figure 5 The SEM images show uniformly dispersed micron-sized particles, which can promote uniform lithium deposition in the negative electrode, limit the deformation of the negative electrode during charging and discharging, and suppress the growth of dendrites in the negative electrode.

[0085] Example 4

[0086] (1) The preparation method of the lanthanum-tin-lithium alloy material differs from that in Example 3 in that the raw materials are lanthanum powder, tin powder and lithium metal sheets. The lanthanum powder and tin powder are manually ground into mixed metal powder.

[0087] (2) The preparation method of the lithium symmetric battery with lanthanum-tin-lithium alloy material as electrode is different from that in Example 3: the electrolyte is a sulfide solid electrolyte (Li3PS4).

[0088] (3) The preparation method of the lithium battery with lanthanum-tin-lithium alloy material as negative electrode is different from that of Example 3: the electrolyte is a sulfide solid electrolyte (Li3PS4), and the positive electrode is a mixture of lithium cobalt oxide, Li3PS4 and Ketjen black in a mass ratio of 7:2.8:0.2.

[0089] Comparative Example 4

[0090] (1) The preparation method of zinc-tin-lithium alloy material differs from that in Example 4 in that the raw materials are zinc sheet, tin sheet and lithium metal sheet. The zinc sheet and tin sheet are repeatedly cold-pressed into a mixed metal block.

[0091] (2) The preparation method of the lithium symmetric battery with zinc-tin-lithium alloy material as electrode is different from that in Example 1: the lanthanum-tin-lithium alloy is replaced with zinc-tin-lithium alloy.

[0092] (3) The preparation method of the lithium battery with zinc-tin-lithium alloy material as negative electrode is different from that of Example 1 in that the lanthanum-tin-lithium alloy is replaced with tin-lithium alloy.

[0093] Figure 7 The electrochemical impedance spectroscopy of the lithium symmetric battery in Example 4 (negative electrode: lanthanum-tin-lithium alloy). Figure 8 The image shows the electrochemical impedance spectroscopy (EIS) of the lithium-ion symmetric battery in Comparative Example 4 (negative electrode: zinc-tin-lithium alloy). Figure 8 compared to, Figure 7 The electrochemical impedance spectroscopy in the sample shows a smaller interfacial impedance, indicating better compatibility and more complete interfacial contact between the lanthanum-tin-lithium alloy anode and the electrolyte layer.

[0094] Example 5

[0095] (1) The preparation method of yttrium-aluminum-lithium alloy material is as follows:

[0096] The raw materials are yttrium powder, aluminum powder, and lithium powder. The yttrium powder, aluminum powder, and lithium powder in a molar ratio of 0.10:0.45:0.45 are manually ground for 10 minutes to obtain a mixed metal powder. Then, the mixed metal powder is placed in a ball mill jar and ball milled for 5 hours in an argon atmosphere at a speed of 400 r / min to obtain yttrium-aluminum-lithium alloy powder.

[0097] (2) The preparation method of a lithium symmetric battery using yttrium-aluminum-lithium alloy material as electrode is as follows:

[0098] The electrolyte is a PEO-based polymer solid electrolyte membrane, and the electrode is a yttrium-aluminum-lithium alloy powder material.

[0099] PEO-based polymer solid electrolyte membranes are cut into circular sheets with a thickness of 100-200 μm and a diameter of 12 mm. Yttrium-aluminum-lithium alloy powder is mixed with a binder, with the binder accounting for 0.5%-5.0% by mass. The mixture is then rolled or pressed to form a yttrium-aluminum-lithium alloy membrane with a mass of 10-20 mg / cm³. 2 The thickness is 100-200μm. The yttrium-aluminum-lithium alloy film is cut into discs with a diameter of 10mm. The cut discs are then placed into a CR2032 button cell mold in the order of yttrium-aluminum-lithium alloy film, PEO-based polymer solid electrolyte film, and yttrium-aluminum-lithium alloy film, and then packaged under a packaging pressure of 0.5t.

[0100] (3) The preparation method of a lithium battery using yttrium-aluminum-lithium alloy material as the negative electrode is as follows:

[0101] The electrolyte is a PEO-based polymer solid electrolyte membrane, the negative electrode is a yttrium-aluminum-lithium alloy membrane, and the positive electrode is a composite of lithium manganese oxide, carbon nanotubes, and a binder.

[0102] Preparation method of the positive electrode: Lithium manganese oxide, carbon nanotubes, and binder are mixed in a mass ratio of 8:1:1. The positive electrode is then loaded onto aluminum foil by coating, with a positive electrode loading of 5.0-10.0 mg / cm³. 2 Cut the aluminum foil loaded with the positive electrode into a circular piece to obtain the positive electrode sheet with a diameter of 10mm.

[0103] The cut discs are placed into the CR2032 button cell mold in the order of yttrium-aluminum-lithium alloy film, PEO-based polymer solid electrolyte film, and positive electrode sheet, and then packaged under a pressure of 0.5t.

[0104] Comparative Example 5

[0105] (1) The preparation method of aluminum-lithium alloy material is different from that in Example 5: the raw materials are aluminum powder and lithium powder, and the molar ratio is 1:1.

[0106] (2) The preparation method of the lithium symmetric battery with aluminum-lithium alloy material as electrode is different from that of Example 5: the yttrium-aluminum-lithium alloy is replaced with aluminum-lithium alloy.

[0107] (3) The preparation method of the lithium battery with aluminum-lithium alloy material as negative electrode is different from that of Example 5: the yttrium-aluminum-lithium alloy is replaced with aluminum-lithium alloy.

[0108] Figure 9 The charge-discharge curve of the lithium battery in Example 5 (negative electrode: yttrium-aluminum-lithium alloy). Figure 10 The charge-discharge curves of the lithium battery in Comparative Example 5 (negative electrode: aluminum-lithium alloy) are shown. Figure 10 compared to, Figure 9 The charge-discharge curves in the figure show greater capacity and lower voltage polarization, indicating that the yttrium-aluminum-lithium alloy anode can achieve a more stable and efficient lithium insertion / extraction process.

[0109] Example 6

[0110] (1) The preparation method of yttrium-aluminum-lithium alloy material is as follows:

[0111] The raw materials are yttrium powder, aluminum powder, and lithium powder in a molar ratio of 2:9:9. The yttrium powder, aluminum powder, and lithium powder are manually ground until homogeneous for 10 minutes. Then, the mixed metal powder is placed in a graphite crucible and calcined in an argon atmosphere for 5 hours at 700℃ to obtain a yttrium-aluminum-lithium alloy block. This block is then placed in a ball mill jar and ball-milled in an argon atmosphere for 5 hours at a speed of 400 r / min to obtain yttrium-aluminum-lithium alloy powder.

[0112] (2) The preparation method of the lithium symmetric battery with yttrium-aluminum-lithium alloy material as electrode is different from that of Example 5 in that the electrolyte is a PAN-based polymer solid electrolyte membrane.

[0113] (3) The preparation method of the lithium battery with yttrium-aluminum-lithium alloy material as negative electrode is different from that of Example 5 in that the electrolyte is a PAN-based polymer solid electrolyte membrane.

[0114] Comparative Example 6

[0115] (1) The preparation method of tin-aluminum-lithium alloy material is as follows:

[0116] The raw materials are tin powder, aluminum powder, and lithium powder in a molar ratio of 2:9:9. The tin powder, aluminum powder, and lithium powder are manually ground until uniform for 10 minutes. Then, the mixed metal powder is placed in a ball mill jar and ball-milled for 5 hours in an argon atmosphere at a speed of 400 r / min to obtain tin-aluminum-lithium alloy powder.

[0117] (2) The preparation method of the lithium symmetric battery with tin-aluminum-lithium alloy material as electrode is different from that of Example 6: the yttrium-aluminum-lithium alloy is replaced with tin-aluminum-lithium alloy.

[0118] (3) The preparation method of the lithium battery with tin-aluminum-lithium alloy material as negative electrode is different from that of Example 6 in that the yttrium-aluminum-lithium alloy is replaced with tin-aluminum-lithium alloy.

[0119] Figure 11 The electrochemical impedance spectroscopy of the lithium symmetric battery in Example 6 (negative electrode: yttrium-aluminum-lithium alloy). Figure 12 The image shows the electrochemical impedance spectroscopy (EIS) of the lithium-ion symmetric battery in Comparative Example 6 (negative electrode: tin-aluminum-lithium alloy). Figure 12 compared to, Figure 11 The electrochemical impedance spectroscopy in the sample shows a smaller interfacial impedance, indicating that the yttrium-aluminum-lithium alloy anode has better compatibility with the electrolyte layer and more sufficient interfacial contact.

[0120] Example 7

[0121] (1) Praseodymium-silicon-lithium alloy material, the preparation method is as follows:

[0122] The raw materials are praseodymium powder, silicon powder, and lithium flakes, with a molar ratio of 1:11:8. The praseodymium and silicon powders are manually ground until homogeneous for 10 minutes. Then, the mixed metal powder is placed in a crucible and calcined at 1000℃ for 1 hour in an argon atmosphere to obtain praseodymium-silicon alloy powder. The lithium flakes are then mixed with the praseodymium-silicon alloy powder and manually ground for 20 minutes to obtain praseodymium-silicon-lithium alloy powder.

[0123] (2) The preparation method of a lithium symmetric battery using praseodymium-silicon-lithium alloy material as electrode is as follows:

[0124] The electrolyte is an oxide solid electrolyte (LLZO) disc; the electrode is a praseodymium-silicon-lithium alloy powder material.

[0125] LLZO discs have a thickness of 200-400 μm and a diameter of 12 mm. Praseodymium-silicon-lithium alloy powder is mixed with a binder (0.5%-5.0% by mass), and then a praseodymium-silicon-lithium alloy film with a mass of 10-20 mg / cm³ is formed by rolling or pressing. 2 The thickness is 100-200μm. The praseodymium-silicon-lithium alloy film is cut into discs with a diameter of 10mm. The cut discs are then placed into a CR2032 button cell mold in the following order: praseodymium-silicon-lithium alloy film, LLZO disc, and praseodymium-silicon-lithium alloy film. A carbonate electrolyte of 100-200μL is added between the praseodymium-silicon-lithium alloy film and the LLZO disc. The mixture is then encapsulated at a pressure of 0.5t.

[0126] (3) The preparation method of the lithium battery with praseodymium-silicon-lithium alloy material as negative electrode is as follows:

[0127] The electrolyte is an LLZO disc; the negative electrode is a praseodymium-silicon-lithium alloy film; and the positive electrode is a composite of nickel-cobalt-manganese ternary material, Ketjen black, and binder.

[0128] Preparation method of the positive electrode: A nickel-cobalt-manganese ternary material, Ketjen black, and a binder are mixed in a mass ratio of 8:1:1. The positive electrode is then loaded onto aluminum foil by coating, with a positive electrode loading of 5.0-10.0 mg / cm³. 2 Cut the aluminum foil loaded with the positive electrode into a circular piece to obtain the positive electrode sheet with a diameter of 10mm.

[0129] The cut discs are placed into the CR2032 button cell mold in the following order: praseodymium-silicon-lithium alloy film, LLZO disc, and positive electrode. Carbonate electrolyte with a volume of 100-200 μL is added between the praseodymium-silicon-lithium alloy film and the LLZO disc, and between the positive electrode and the LLZO disc. The mold is then sealed at a pressure of 0.5t.

[0130] Comparative Example 7

[0131] (1) Silicon-lithium alloy material, the preparation method is as follows:

[0132] The raw materials are silicon powder and lithium foil in a molar ratio of 1:1. The lithium foil and silicon powder are mixed and manually ground for 20 minutes to obtain silicon-lithium alloy powder.

[0133] (2) The preparation method of the lithium symmetric battery with silicon-lithium alloy material as electrode is different from that of Example 7: the praseodymium-silicon-lithium alloy is replaced with silicon-lithium alloy.

[0134] (3) The preparation method of the lithium battery with praseodymium-silicon-lithium alloy material as negative electrode is different from that of Example 7: the praseodymium-silicon-lithium alloy is replaced with silicon-lithium alloy.

[0135] Figure 13 The electrochemical impedance spectroscopy (EIS) of the lithium symmetric battery after cycling in Example 7 (negative electrode: praseodymium-silicon-lithium alloy) is shown. Figure 14 The image shows the electrochemical impedance spectroscopy (EIS) of the lithium-ion symmetric battery in Comparative Example 7 after cycling (negative electrode: silicon-lithium alloy). Figure 14 compared to, Figure 13 The electrochemical impedance spectroscopy in the sample showed a smaller interfacial impedance, indicating that the praseodymium-silicon-lithium alloy anode and the electrolyte layer can maintain better interfacial contact after battery cycling.

[0136] Example 8

[0137] (1) The preparation method of praseodymium-silicon-lithium alloy material is different from that in Example 7: the calcination temperature of the mixed metal powder is 900℃ and the calcination time is 5h. The lithium powder and praseodymium-silicon alloy powder are mixed, the ball milling speed is 400r / min and the ball milling time is 2h.

[0138] (2) The preparation method of the lithium symmetric battery with praseodymium-silicon-lithium alloy material as electrode is different from that of Example 7 in that the electrolyte is an oxide solid electrolyte (LATP) disc.

[0139] (3) The preparation method of the lithium battery with praseodymium-silicon-lithium alloy material as negative electrode is different from that of Example 7 in that the electrolyte is an oxide solid electrolyte (LATP) disc.

[0140] Comparative Example 8

[0141] (1) The preparation method of magnesium-silicon-lithium alloy material is different from that in Example 8: the raw materials are magnesium powder, silicon powder and lithium powder.

[0142] (2) The preparation method of the lithium symmetric battery with magnesium-silicon-lithium alloy material as electrode is different from that of Example 8: the praseodymium-silicon-lithium alloy is replaced with magnesium-silicon-lithium alloy.

[0143] (3) The preparation method of the lithium battery with magnesium-silicon-lithium alloy material as negative electrode is different from that of Example 8: the praseodymium-silicon-lithium alloy is replaced with magnesium-silicon-lithium alloy.

[0144] Figure 15 The charge-discharge curve of the lithium battery in Example 8 (negative electrode: praseodymium-silicon-lithium alloy). Figure 16The charge-discharge curves of the lithium battery in Comparative Example 8 (negative electrode: magnesium-silicon-lithium alloy) are shown. Figure 16 compared to, Figure 15 The charge-discharge curves in the praseodymium-silicon-lithium alloy exhibit more stable performance and less capacity decay, indicating that the praseodymium-silicon-lithium alloy anode can maintain more sufficient and stable lithium-ion diffusion during charge and discharge.

[0145] Example 9

[0146] (1) The preparation method of yttrium-silicon-graphite-lithium alloy material is as follows:

[0147] The raw materials are yttrium powder, silicon powder, graphite powder, and lithium powder, with a molar ratio of 1:5:9:5. The yttrium powder, silicon powder, graphite powder, and lithium powder are manually ground until homogeneous for 10 minutes. Then, the mixed metal powder is placed in a ball mill jar and ball-milled for 5 hours in an argon atmosphere at a speed of 400 r / min to obtain yttrium-silicon-graphite-lithium alloy powder.

[0148] (2) The preparation method of a lithium symmetric battery using yttrium-silicon-graphite-lithium alloy material as electrode is as follows:

[0149] The electrolyte is an ether-based electrolyte; the electrode is a yttrium-silicon-graphite-lithium alloy powder material.

[0150] Glass fiber diaphragms are cut into discs with a diameter of 16 mm, and then impregnated with an ether-based electrolyte (volume 200-400 μL) to obtain an electrolyte / diaphragm sheet. Yttrium-silicon-graphite-lithium alloy powder is mixed with a binder (mass percentage 0.5%-5.0%), and then rolled or pressed to form a yttrium-silicon-graphite-lithium alloy membrane with a mass of 10-20 mg / cm³. 2 Thickness 100-200μm. Cut the yttrium-silicon-graphite-lithium alloy film into circular pieces with a diameter of 10mm. Place the cut circular pieces into the CR2032 button battery mold in the following order: yttrium-silicon-graphite-lithium alloy film, electrolyte / separator, yttrium-silicon-graphite-lithium alloy film. Seal the battery under a sealing pressure of 0.5t.

[0151] (3) The preparation method of the lithium battery with yttrium-silicon-graphite-lithium alloy material as negative electrode is as follows:

[0152] The electrolyte is an ether-based electrolyte; the negative electrode is a yttrium-silicon-graphite-lithium alloy film; and the positive electrode is a composite of selenium disulfide, acetylene black, and binder.

[0153] Preparation method of the positive electrode: Selenium disulfide, Ketjen black, and binder are mixed in a mass ratio of 7:2:1. The positive electrode is then loaded onto aluminum foil by coating, with a positive electrode loading of 5.0-10.0 mg / cm³. 2 Cut the aluminum foil loaded with the positive electrode into a circular piece to obtain the positive electrode sheet with a diameter of 10mm.

[0154] The cut discs are placed into the CR2032 button cell mold in the following order: yttrium-silicon-graphite-lithium alloy film, electrolyte / separator, and positive electrode sheet. The mold is then sealed under a sealing pressure of 0.5t.

[0155] Comparative Example 9

[0156] (1) The preparation method of silicon-graphite-lithium alloy material is different from that in Example 9: the raw materials are silicon powder, graphite powder and lithium powder, and the molar ratio is 1:2:1.

[0157] (2) The preparation method of the lithium symmetric battery with silicon-graphite-lithium alloy material as electrode is different from that of Example 9 in that the yttrium-silicon-graphite-lithium alloy is replaced with silicon-graphite-lithium alloy.

[0158] (3) The preparation method of the lithium battery with silicon-graphite-lithium alloy material as negative electrode is different from that of Example 9: the yttrium-silicon-graphite-lithium alloy is replaced with silicon-graphite-lithium alloy.

[0159] Figure 17 The cycle performance of the lithium battery in Example 9 (negative electrode: yttrium-silicon-graphite-lithium alloy). Figure 18 The cycle performance of the lithium battery in Comparative Example 9 (negative electrode: silicon-graphite-lithium alloy) is compared with... Figure 18 compared to, Figure 17 The battery exhibits more stable cycle performance and higher capacity retention, indicating that the yttrium-silicon-graphite-lithium alloy anode can maintain more sufficient and stable lithium-ion diffusion during charge and discharge.

[0160] Example 10

[0161] (1) The preparation method of yttrium-silicon-graphite-lithium alloy material is as follows:

[0162] The raw materials are yttrium powder, silicon powder, graphite powder, and lithium powder, with a molar ratio of 1:4:9:6. The yttrium powder, silicon powder, graphite powder, and lithium powder are manually ground until homogeneous for 20 minutes. Then, the mixed metal powder is placed in a ball mill jar and ball-milled for 10 hours in an argon atmosphere at a speed of 300 r / min to obtain yttrium-silicon-graphite-lithium alloy powder.

[0163] (2) The preparation method of the lithium symmetric battery with yttrium-silicon-graphite-lithium alloy material as electrode is different from that of Example 9 in that the electrolyte is a carbonate electrolyte.

[0164] (3) The preparation method of the lithium battery with yttrium-silicon-graphite-lithium alloy material as negative electrode is different from that of Example 9 in that the electrolyte is a carbonate electrolyte.

[0165] Comparative Example 10

[0166] (1) The preparation method of tin-silicon-graphite-lithium alloy material is different from that of Example 9 in that the raw materials are tin powder, silicon powder, graphite powder and lithium powder.

[0167] (2) The preparation method of the lithium symmetric battery with tin-silicon-graphite-lithium alloy material as electrode is different from that of Example 9: the yttrium-silicon-graphite-lithium alloy is replaced with tin-silicon-graphite-lithium alloy.

[0168] (3) The preparation method of the lithium battery with tin-silicon-graphite-lithium alloy material as negative electrode is different from that of Example 9: the yttrium-silicon-graphite-lithium alloy is replaced with tin-silicon-graphite-lithium alloy.

[0169] Figure 19 The charge-discharge curve of the lithium battery in Example 10 (negative electrode: yttrium-silicon-graphite-lithium alloy). Figure 20 The charge-discharge curves of the lithium battery in Comparative Example 10 (negative electrode: tin-silicon-graphite-lithium alloy) are shown. Figure 20 compared to, Figure 19 The charge-discharge curves show a larger capacity and less significant decay, indicating that the yttrium-silicon-graphite-lithium alloy anode can maintain more sufficient and stable lithium-ion diffusion during charge and discharge.

[0170] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0171] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a rare earth-based lithium alloy anode material, characterized in that, Includes the following steps: S1: Mechanically mix rare earth elements with active materials to obtain a rare earth-active material mixture; S2: Calcine the rare earth-active material mixture obtained in step S1 at 500-1500℃ for 1-10 hours to obtain rare earth-based alloy material; S3: Mechanically mix lithium metal with the rare earth-based alloy material obtained in step S2 to obtain a rare earth-based lithium alloy material. The molar ratio of rare earth, active material, and lithium metal is 1-50:1-99:1-99; The active material is one or more of indium, tin, aluminum, magnesium, silicon, germanium, antimony, bismuth, graphite, graphene, hard carbon, and soft carbon.

2. The method for preparing a rare earth-based lithium alloy anode material as described in claim 1, characterized in that, The rare earth elements include one or more of scandium, yttrium, lanthanum, cerium, spectroscopy, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

3. The method for preparing a rare earth-based lithium alloy anode material as described in claim 1, characterized in that, The lithium metal is one or more of lithium blocks, lithium sheets, and lithium powder.

4. A rare earth-based lithium alloy anode material prepared by the method according to any one of claims 1-3.

5. The application of the rare earth-based lithium alloy anode material as described in claim 4 in lithium batteries.

6. The application of the rare earth-based lithium alloy anode material as described in claim 5 in lithium batteries, characterized in that, It includes a negative electrode, an electrolyte, and a positive electrode, wherein the negative electrode is the rare earth-based lithium alloy negative electrode material.

7. The application of the rare earth-based lithium alloy anode material as described in claim 6 in lithium batteries, characterized in that, The electrolyte includes one or two of liquid electrolytes and solid electrolytes. The liquid electrolyte includes one or two of carbonate electrolytes and ether electrolytes. The solid electrolyte includes one or more of polymer electrolytes, oxide electrolytes, sulfide electrolytes, and halide electrolytes.

8. The application of the rare earth-based lithium alloy anode material as described in claim 7 in lithium batteries, characterized in that, The positive electrode comprises 10%-90% positive electrode active material, 0-70% solid electrolyte, 0-20% carbon material, and 0-10% binder. The positive electrode active material is a lithium-containing positive electrode or a lithium-free positive electrode, and the carbon material is soft carbon or hard carbon.

9. The application of the rare earth-based lithium alloy anode material as described in claim 7 in lithium batteries, characterized in that, The positive electrode comprises 10%-90% positive electrode active material, 0-70% solid electrolyte, 0-20% carbon material, and 0-10% binder. The positive electrode active material is a lithium-containing positive electrode or a lithium-free positive electrode. The carbon material includes one or more combinations of acetylene black, Ketjen black, carbon nanotubes, graphite, graphene, activated carbon, and carbon fiber.

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