All-solid-state battery and method for preparing same

Abstract

The present invention discloses an all-solid-state battery and a preparation method thereof, belonging to the technical field of solid-state batteries. It includes the processes of crushing, mixing, and coating of the electrolyte. Each process uses the acoustic resonance method to obtain the final solid electrolyte, and based on the prepared solid electrolyte, the electrode material is prepared by the acoustic resonance method. The specific capacity of the electrode material prepared by the acoustic resonance method is increased, and compared with the existing mainstream ball milling process, the process time is reduced from several hours to the minute level, greatly improving the efficiency of each process, and further improving the preparation efficiency of the entire all-solid-state battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state batteries, and particularly relates to an all-solid-state battery and a preparation method thereof. Background Art

[0002] As a simple and efficient energy storage system, lithium-ion batteries have received great attention at all levels of the development of modern energy technologies. However, the organic electrolytes of traditional liquid batteries have problems such as being toxic and flammable during use, and lithium dendrites are prone to penetrate the separator, causing internal short circuits in the battery, making the liquid batteries have potential safety hazards such as explosion and fire. Therefore, replacing the electrolyte and separator in traditional lithium-ion batteries with solid electrolytes and developing safe, excellent-performance and low-cost all-solid-state batteries have become major challenges in the energy field in the world today.

[0003] For sulfide solid electrolytes or halide solid electrolytes, the preparation process usually includes processes such as crushing, coating, mixing, and bonding; for the crushing process, the solid electrolytes are generally large micron-sized particles after synthesis, but large particle sizes are not easy to prepare a solid electrolyte membrane and are not conducive to the improvement of the volume energy density, so crushing is required. The traditional method is to use ball milling for secondary particle refinement, but the overall process is relatively cumbersome. In addition to requirements for the ball-to-material ratio and rotation speed, it also requires a long time of ball milling, which is not conducive to continuous production. Solid electrolyte coating is a method of coating a solid electrolyte material on the surface of an electrode material (such as a positive electrode material), which can reduce side reactions and enhance the stability and cycling performance of the electrode material. However, in the coating process, physical or chemical means are often required for deposition coating, the process is relatively cumbersome, and there are high requirements for the coating material, which is not conducive to efficient continuous production. In addition, the mixing of the positive and negative electrodes needs to consider both performance and efficiency. The traditional process often uses ball milling for mixing. Although the dispersion is well guaranteed, it greatly affects the production efficiency of solid-state batteries and is difficult to produce continuously. On the other hand, in the process of separator production, the dispersion process of the binder will affect the film-making efficiency, and its dispersion directly affects the battery rate performance. However, the binder is difficult to disperse quickly during the film-making process, which affects the continuous production process, and too much binder will affect the performance of the separator.

[0004] Therefore, in the production process of solid-state batteries, due to process limitations, the production efficiency of current solid electrolytes is relatively low, and it is difficult to achieve continuous operation and production of solid-state batteries. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned disadvantages of the prior art and provide an all-solid-state battery and a preparation method thereof, so as to solve the problem that the production efficiency of each stage in the production process of solid-state batteries in the prior art is low and it is difficult to achieve continuous production.

[0006] To achieve the above object, the present invention is implemented by the following technical solutions:

[0007] The first aspect of the present invention discloses a preparation method of an all-solid-state battery, comprising the following steps:

[0008] S1. Respectively crush the positive electrolyte and the negative electrolyte by the acoustic resonance method to obtain positive electrolyte powders with M1 grade particle sizes and negative electrolyte powders with M2 grade particle sizes, where both M1 and M2 are natural numbers greater than or equal to 2; the positive electrolyte is a halide, and the negative electrolyte is a sulfide;

[0009] S2. Mix positive electrolyte powders with N1 grade particle sizes, and form a positive solid electrolyte by the acoustic resonance method; mix negative electrolyte powders with N2 grade particle sizes, and form a negative solid electrolyte by the acoustic resonance method, where both N1 and N2 are natural numbers greater than or equal to 2;

[0010] S3. Mix the positive solid electrolyte and the positive electrode material by the acoustic resonance method to form a modified positive electrode in a coated form; mix the negative solid electrolyte and the negative electrode material by the acoustic resonance method to form a modified negative electrode in a coated form;

[0011] S4. After combining the modified positive electrode, the separator and the modified negative electrode, an all-solid-state battery is obtained.

[0012] Preferably, in S3, the negative electrode material is nano-silicon, micro-silicon or lithium negative electrode, and the positive electrode material is a ternary nickel-based material or nickel cobalt manganese oxide, indicating that this method can be applied to the most common negative electrode materials and positive electrode materials on the market.

[0013] Preferably, in S2, the positive electrolyte powders with N1 grade particle sizes and the negative electrolyte powders with N2 grade particle sizes both satisfy particle grading. During the mixing process, adopting a particle grading scheme can improve the compaction density of the electrolyte.

[0014] Preferably, the modified positive electrode in S3 is composed of a coating material and a material to be coated. When the coating material is the positive solid electrolyte, the material to be coated is the positive electrode material; when the coating material is the positive electrode material, the material to be coated is the positive solid electrolyte;

[0015] The modified negative electrode is composed of a coating material and a material to be coated. When the coating material is the negative solid electrolyte, the material to be coated is the negative electrode material; when the coating material is the negative electrode material, the material to be coated is the negative solid electrolyte. The selection of the coating material and the material to be coated can be adjusted according to the actual situation.

[0016] Preferably, both the coating material and the material to be coated are granular, and the particle size of the granular material to be coated is more than one hundred times that of the granular coating material. Distinguishing the particle sizes of the coating material and the material to be coated can complete the coating process and ensure the coating effect.

[0017] Preferably, in S1, S2, and S3, the parameters controlled by the acoustic resonance method include frequency, acceleration, and time. By adjusting parameters such as the time, frequency, and acceleration of the acoustic resonance method, processes such as the crushing and mixing of the positive electrode electrolyte and the negative electrode electrolyte of the solid-state battery, and the coating of the large and small particle sizes of the positive electrode and the negative electrode of the battery can be realized, making this method applicable to the entire process of preparing all-solid-state batteries.

[0018] Preferably, in S4, the separator is a double-layer separator, the double-layer separator is a halide separator and a sulfide separator respectively, and both the halide separator and the sulfide separator are obtained by the acoustic resonance method. Preparing the halide separator and the sulfide separator by the acoustic resonance method can improve the preparation efficiency of the separator.

[0019] Preferably, the specific process of preparing the separator is as follows: a sulfide mass mixture is obtained by mixing the negative electrode solid electrolyte and the binder by the acoustic resonance method, and the sulfide mass mixture is extruded into a film to obtain a sulfide separator; a halide mass mixture is prepared by mixing the positive electrode solid electrolyte and the binder by the acoustic resonance method, and the halide mass mixture is extruded into a film to obtain a halide separator; the sulfide separator and the halide separator are co-extruded and compounded to obtain a double-layer separator. During the preparation process of the separator, the binder and the solid electrolyte material form a mass mixture by the acoustic resonance method, so that the binder is dispersed quickly and evenly, thereby reducing the amount of the binder used and further improving the performance of the separator.

[0020] Preferably, in the sulfide mass mixture, the mass of the binder is 0.5%-3% of the mass of the negative electrode solid electrolyte; in the halide mass mixture, the mass of the binder is 0.5%-3% of the mass of the positive electrode solid electrolyte. During the preparation of the separator by the acoustic resonance method in the present invention, the addition amount of the binder in the separator is lower than the conventional addition amount of about 5% of the binder.

[0021] An all-solid-state battery prepared by any one of the above preparation methods includes a modified positive electrode, a separator, and a modified negative electrode.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention discloses a preparation method of an all-solid-state battery. In the process of preparing the positive solid electrolyte and the negative solid electrolyte of the all-solid-state battery, both include the processes of crushing and mixing the electrolyte, and then the modified positive electrode and the modified negative electrode in the form of coating are formed by the acoustic resonance method. By the acoustic resonance method, the present invention can mix electrolyte powders with different particle sizes evenly, and a large amount of electrolyte can be prepared at one time. Further, through the acoustic resonance method for coating, the prepared modified positive electrode and modified negative electrode have a complete structure and uniform particle size. Compared with other methods, the coating time can be greatly reduced, and the coating effect can be enhanced. Finally, the obtained electrode has a better specific capacity than direct stirring. In the method of the present invention, the acoustic resonance method is used in each step of the process of preparing the modified positive electrode and the modified negative electrode of the all-solid-state battery. Compared with the existing ball milling process, the process time is reduced from several hours to several minutes, the crushing efficiency is greatly improved, and the efficiency is higher and the stability is better than the ball milling process.

[0024] The present invention also discloses an all-solid-state battery. In the preparation process of the modified positive electrode, the modified negative electrode or the separator in the all-solid-state battery, the acoustic resonance method is used, and the solid electrolyte used in the preparation process is the solid electrolyte prepared by the above-mentioned acoustic resonance method, so that the uniformity of the positive and negative electrode materials and the separator is better. The performance data of the solid-state battery obtained by this method have obvious advantages compared with traditional methods such as ball milling, and show good performance while improving production efficiency. Description of the Drawings

[0025] Figure 1 It is a comparison diagram before and after crushing the negative electrode electrolyte by the acoustic resonance method;

[0026] Among them, Figure (a) is a schematic diagram of the raw material; Figure (b) is the result diagram after acoustic resonance;

[0027] Figure 2 For nano-silicon coated Li 5.5 PS 4.5 SEM (scanning electron microscope) schematic diagram of the negative solid electrolyte of Cl;

[0028] Figure 3 It is a comparison diagram of the constant current charge and discharge performance test results of Example 1 and Comparative Example 1;

[0029] Figure 4 It is a graph of the first cycle voltage capacity test results of Example 2, Comparative Example 2 and Comparative Example 3;

[0030] Figure 5 It is a graph of the charge and discharge capacity test results of the half-cells obtained in Example 2 and Comparative Example 3;

[0031] Figure 6Test cycle comparison diagram of all-solid-state batteries for Example 4 and Comparative Example 4;

[0032] Figure 7 Charge and discharge performance test diagram of the all-solid-state battery for Example 5;

[0033] Figure 8 Charge and discharge performance test diagram of the all-solid-state battery for Example 6;

[0034] Figure 9 Charge and discharge performance test diagram of the all-solid-state battery for Example 7;

[0035] Figure 10 Charge and discharge performance test diagram of the all-solid-state battery for Example 8. Detailed implementation manners

[0036] The present invention will be further described in detail below with reference to the accompanying drawings:

[0037] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meaning understood by those skilled in the art with respect to the present invention. In case of conflict, the definition in this specification shall prevail.

[0038] In this article, unless otherwise specified, "comprising", "including", "containing", "having" or similar terms cover the meanings of "consisting of" and "consisting essentially of". For example, "A comprises a" covers the meanings of "A comprises a and others" and "A consists only of a".

[0039] The present invention will be further illustrated with reference to specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0040] Conventional instruments and equipment in the art are used in the following embodiments. The experimental methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Various raw materials are used in the following embodiments. Unless otherwise stated, commercially available products are used, and their specifications are the conventional specifications in the art. In the specification of the present invention and the following embodiments, unless otherwise specified, "%" represents weight percentage, "parts" represents weight parts, and the ratios represent weight ratios.

[0041] The core idea of the present invention is to prepare a positive electrode electrolyte and a negative electrode electrolyte by means of acoustic resonance method, and further prepare a modified positive electrode, a modified negative electrode and a separator rapidly by acoustic resonance method, and then prepare a all-solid-state battery, so that the all-solid-state battery can be prepared on a large scale and efficiently.

[0042] The first aspect of the present invention discloses a method for preparing an all-solid-state battery, comprising the following steps:

[0043] S1, respectively crush the positive electrode electrolyte and the negative electrode electrolyte by acoustic resonance method to obtain positive electrode electrolyte powder with M1 grade particle sizes and negative electrode electrolyte powder with M2 grade particle sizes, where both M1 and M2 are natural numbers greater than or equal to 2; the positive electrode electrolyte is a halide, and the negative electrode electrolyte is a sulfide;

[0044] S2, mix the positive electrode electrolyte powder with N1 grade particle sizes, and form a positive electrode solid electrolyte by acoustic resonance method, mix the negative electrode electrolyte powder with N2 grade particle sizes, and form a negative electrode solid electrolyte by acoustic resonance method, where both N1 and N2 are natural numbers greater than or equal to 2;

[0045] S3, mix the positive electrode solid electrolyte and the positive electrode material by acoustic resonance method to form a modified positive electrode in a coated form, mix the negative electrode solid electrolyte and the negative electrode material by acoustic resonance method to form a modified negative electrode in a coated form;

[0046] S4, combine the modified positive electrode, the separator and the modified negative electrode to obtain an all-solid-state battery.

[0047] The acoustic resonance method refers to that when a system (such as a cavity) is acted on by an external sound wave, it vibrates at a certain frequency and amplitude. If the frequency of the external sound wave is close to or equal to the natural frequency of the system, the vibration amplitude of the system will increase sharply, and resonance will occur. This is because the external sound wave provides additional energy for the system, enabling it to overcome the internal damping force and vibrate with a larger amplitude. The acoustic resonance method used in the present invention is to use an acoustic resonance device to perform processes such as crushing, mixing, coating and dispersing of materials.

[0048] In some embodiments of the present invention, in S1, the specific halide can be any one or more of Li3InCl6, Li2ZrCl6, Li3TaCl6, Li3NbCl6, Li3AlCl6, Li3GaCl6, Li 2+x In x Zr 1-x Cl6 oxyhalide (the range of x is 0 to 1), LiNbOCl, LiTaOCl4, Li2ZrOCl4 or LiNbOCl4.

[0049] The sulfide can be Li6PS5Cl, Li 5.5 PS4.5 Cl, Li 5.5 PS5Cl, Li 5.4 PS5Cl, Li 5.3 PS5Cl or Li 5.5 PS5Cl y Br 1-y Any one or more of them (where the range of y is 0 to 1).

[0050] It can be seen that the method for preparing the electrolyte in the present invention is applicable to common halide solid electrolytes and sulfide solid electrolytes, making this method have great universality and promotional value.

[0051] It should be understood that in S1, after the positive electrode electrolyte and the negative electrode electrolyte are broken by the acoustic resonance method, they are in powder form. After screening, positive electrode electrolyte powder with M1 grade particle sizes and negative electrode electrolyte powder with M2 grade particle sizes are obtained. The specific values of M1 and M2 are determined according to the actual situation. This step is a physical refinement process, which makes the particles of the electrolyte smaller and forms electrolyte powders with different particle sizes.

[0052] Furthermore, in S2, among the above-mentioned positive electrode electrolyte powders with M1 grade particle sizes, N1 grade particle sizes of positive electrode electrolyte powders that meet the particle size grading requirements are found, and positive electrode solid electrolyte is formed by the acoustic resonance method; among the above-mentioned negative electrode electrolyte powders with M2 grade particle sizes, N2 grade particle sizes of negative electrode electrolyte powders that meet the particle size grading requirements are found, and negative electrode solid electrolyte is formed by the acoustic resonance method. Therefore, N1 is less than M1, and N2 is less than M2. In this step, particle size grading can improve the compaction density of the electrolyte. Different target-sized solid electrolyte particles have different grading requirements to achieve the maximum compaction density. Through particle size grading, on the basis of taking into account high ionic conductivity, the growth of lithium dendrites can be reduced. The mixing process mixes electrolyte powders with different particle sizes and then uses them to achieve the highest density, obtaining positive electrode solid electrolyte or negative electrode solid electrolyte.

[0053] In some embodiments of the present invention, the specific process of breaking in S1 is as follows: First, zirconia beads accounting for 25% of the volume of the container are added to the acoustic resonance device, and the positive electrode electrolyte or the negative electrode electrolyte to be broken is continuously filled into the acoustic resonance container of the acoustic resonance device until the set volume filling ratio of the acoustic resonance container is reached. Then it is fixed in the acoustic resonance device and resonance breaking is carried out according to the set frequency. The positive electrode electrolyte or the negative electrode electrolyte is broken into electrolyte powders with multiple grade particle sizes. Through screening, positive electrode electrolyte powder with M1 grade particle sizes or negative electrode electrolyte powder with M2 grade particle sizes is obtained.

[0054] It should be understood that the crushing process of S1 has different frequencies and accelerations for different acoustic resonance devices and different particle size requirements, so that the particle size of the electrolyte powder obtained can meet the requirements. In some specific embodiments, the crushing process is to adjust the acceleration to 100g at a frequency of 60Hz and maintain it for 10min-50min, where Hz is the abbreviation of the frequency unit Hertz, g is the unit of gravity acceleration, 1g=9.8m / s²; min represents minutes, which is the abbreviation of minutes.

[0055] In some embodiments of the present invention, in the mixing process of S2, different equipment and different particle size grades require different frequencies, times and accelerations. In a specific embodiment, the mixing process is adjusted to 60g-100g at a frequency of 30Hz-70Hz and maintained for 3min-10min; exemplarily, the mixing frequency can be 30Hz, 40Hz, 50Hz, 60Hz or 70Hz, exemplarily, the acceleration can be 60g, 70g, 80g, 90g or 100g, and exemplarily, the holding time after reaching the target acceleration can be 3min, 5min, 8min or 10min.

[0056] In some embodiments, the mixing process of S2 can also be mixed in stages, such as mixing for 3 minutes each time, mixing 5 times, and mixing for a total of 15 minutes.

[0057] In a specific embodiment, in S2, positive electrode electrolyte powder or negative electrode electrolyte powder accounting for 90% of the volume of the acoustic resonance container is finally added to the acoustic resonance device, fixed in the acoustic resonance device, and vibration mixing is started to obtain a positive electrode solid electrolyte or a negative electrode solid electrolyte.

[0058] In some embodiments of the present invention, in S3, the modified positive electrode and the modified negative electrode are both composed of a coating material and a coated material, and the particle size of the coating material is smaller than that of the coated material, so that the two types of materials can be agglomerated and adsorbed. For the modified positive electrode, which of the positive electrode solid electrolyte and the positive electrode material is used as the coating material and which is used as the coated material is determined according to demand; for the modified negative electrode, which of the negative electrode solid electrolyte and the negative electrode material is used as the coating material and which is used as the coated material is determined according to demand; during the coating process, the coating material and the coated material are placed in an acoustic resonance device according to a set ratio, and a modified positive electrode and a modified negative electrode in a coated form are formed by an acoustic resonance method. This process is a physical adsorption process. When the coating material and the coated material are at the nanometer and micrometer levels, the surface adsorption effect is strong, and they will spontaneously agglomerate and adsorb to form a coated form.

[0059] During the coating process, the addition amounts of the coating material and the material to be coated are related to the mass, volume, and specific surface area of the finally formed modified positive electrode or modified negative electrode. The basic requirement is that the coating material completely wraps the material to be coated, and the specific thickness is adjusted according to the actual situation.

[0060] Both the modified positive electrode and the modified negative electrode prepared by the method of the present invention are core-shell structures, where the core is the material to be coated, and the shell is composed of granular coating material, and the granular coating material adheres to the material to be coated.

[0061] In some preferred embodiments, the particle size of the material to be coated is more than one hundred times that of the coating material to ensure the coating effect.

[0062] In some specific embodiments, the positive electrode electrolyte is a halide, and the corresponding positive electrode material is a ternary nickel-based material or nickel cobalt manganese oxide, etc.; the negative electrode electrolyte is a sulfide, and the corresponding negative electrode material is micron silicon, nano silicon, or lithium negative electrode.

[0063] In some specific embodiments, for the modified negative electrode with a coating form that needs to be able to control the volume expansion of the negative electrode, the coating material is selected as micron Si, and the material to be coated is selected as sulfide 651 electrolyte. The particles of the material to be coated are about 100 times the size of the coating material. If the direction of enhancing ion conduction is selected, larger micron Si and smaller particle size sulfide electrolyte can be selected. In this case, micron Si is the material to be coated, and sulfide electrolyte is the coating material to prepare the modified negative electrode.

[0064] The sulfide 651 electrolyte is mainly a sulfide, such as Li6PS5Cl, Li 10 GeP2S 12 、Li 5.5 PS5Cl 1.5 or Li 5.5 PS5C l0.75 Br 0.75 .

[0065] In a specific embodiment, when preparing the modified positive electrode material, the coating material can be lithium niobate, and the material to be coated can be nickel cobalt manganese oxide.

[0066] In some specific embodiments, during the coating process of S3, different devices and different particle size grades require different frequencies, times, and accelerations. The process parameters of the coating process are as follows: the acceleration is adjusted to 80g - 90g and maintained for 5min - 15min at a frequency of 30Hz - 80Hz. Preferably, the frequency range is 55Hz - 60Hz. Exemplarily, the frequency can be 30Hz, 40Hz, 50Hz, 55Hz, or 60Hz. Exemplarily, the acceleration is 80g, 85g, or 90g. Exemplarily, the holding time is 5min, 10min, or 15min.

[0067] In some embodiments of the present invention, when preparing the modified cathode, in addition to the coating material and the material to be coated, a conductive agent is also added. The process of adding the conductive agent can be a one-step method or a two-step method. The one-step method is to directly mix the cathode solid electrolyte, the cathode material, and the conductive agent and then prepare the modified cathode by the acoustic resonance method. The two-step method is to first mix the cathode solid electrolyte and the cathode material by the acoustic resonance method to obtain a coated cathode, and then mix the coated cathode and the conductive agent by the acoustic resonance method to obtain the final modified cathode. In the modified cathode with the added conductive agent, the coated cathode is compounded on the conductive agent. It should be noted that when preparing the modified cathode with the added conductive agent by the one-step method, the frequency and acceleration are larger than the above parameters to provide more energy for the acoustic resonance method.

[0068] Specific conductive agents can be Ketjen black, VGCF (abbreviation for Vapor Grown Carbon Fibers, vapor-grown carbon fibers), super-P (small particle conductive carbon black), or single-walled carbon nanotubes.

[0069] In some embodiments of the present invention, the separator can also be prepared by the acoustic resonance method. The separator includes two layers of a halide separator and a sulfide separator pasted together, which is a double-layer separator. The specific preparation process of the separator is as follows: first, the halide separator and the sulfide separator are prepared separately, and then the two separators are directly compounded by roll pressing. Since there is a certain binder inside the separator itself, there is no need to add other substances and they can be directly compounded. This method can obtain a dense and uniform solid electrolyte membrane when mixing under loose loading conditions, greatly simplifying the membrane production process.

[0070] During the specific preparation process of the halide separator or the sulfide separator, the corresponding cathode solid electrolyte or anode solid electrolyte is mixed with the binder by the acoustic resonance method to obtain a halide mass mixture or a sulfide mass mixture. After roll pressing the mass mixture, the corresponding separator is obtained. In the sulfide mass mixture, the mass of the binder is 0.5% - 3% of the mass of the anode solid electrolyte. In the halide mass mixture, the mass of the binder is 0.5% - 3% of the mass of the cathode solid electrolyte.

[0071] The thickness range of the halide separator or sulfide separator is both 20 μm - 200 μm.

[0072]

[0072] In some specific embodiments, in this step, the binder and the solid electrolyte (the positive solid electrolyte or the negative solid electrolyte) are added into the acoustic resonance device according to the amount and mixed by the acoustic resonance method. The frequency during the mixing process is 40 Hz - 80 Hz, preferably 55 Hz - 60 Hz, the acceleration is 60 g - 100 g, preferably 60 g - 90 g, and the mixing time is 3 min - 20 min, preferably 5 min - 10 min.

[0073]

[0073] In a specific embodiment, the binder is tetrafluoroethylene (abbreviated as PTFE, also known as Teflon). At a frequency of 60 Hz, the acceleration is adjusted to 60 g and maintained for 10 min. During this process, tetrafluoroethylene unfolds from the agglomerated state to the fibrous state, and can better combine with the solid electrolyte.

[0074]

[0074] In some embodiments of the present invention, in the above S1 - S4, the filling ratio in the acoustic resonance device is 50% - 100%, preferably 80% - 90%.

[0075] Based on the above preparation method, the present invention also discloses an all - solid - state battery, which includes a modified positive electrode, a modified negative electrode and a separator, wherein both the modified positive electrode and the modified negative electrode are prepared by the above - mentioned acoustic resonance method.

[0076]

[0076] As a preferred solution, the modified positive electrode, the modified negative electrode and the separator in the all - solid - state battery are all prepared by the acoustic resonance method based on the above - mentioned solid electrolyte. The separator is a double - layer separator. The sulfide separator is closer to the modified negative electrode, and the halide separator is closer to the modified positive electrode.

[0077] As can be seen from the above process, the present invention can achieve processes such as crushing, mixing, and coating through a sound resonance device. The specific functions that can be achieved depend on the energy input into the sound resonance. Specifically, during the sound resonance process, the frequency, time, and acceleration need to be controlled. When the energy is large and there is a shearing force, particle crushing can be achieved, and generally, it only targets single-particle crushing. When the energy is small and there are various types of particles, and the particle size distributions are similar or not much different, the particles tend to be evenly distributed under the action of sound resonance. When the energy is small and there are two or more particle sizes with a large difference, a coating material is formed. Generally speaking, nano can achieve uniform coating of micron particles. When forming a separator, forming a lump-like mixture is also a kind of mixing. Since PTFE is fibrous, but it often agglomerates into particles at room temperature, sound resonance can expand these particles, so it is equivalent to evenly dispersing the fibers. After completion, the lump-like mixture is roll-pressed to obtain a separator. The method of the present invention can quickly and efficiently use electrolytes to coat electrode materials, and can quickly prepare a separator with a small amount of binder, so it can mass-produce solid-state batteries efficiently.

[0078] The following is further described with specific embodiments.

[0079] Example 1

[0080] This example prepares a modified negative electrode and verifies the performance of the modified negative electrode, which specifically includes the following steps:

[0081] (1) Add 10 g of zirconia beads with a particle size of φ8 mm to a 15 mL sound resonance device, fill Li 5.5 PS 4.5 Cl (abbreviated as LPSC) electrolyte to 80% of the volume of the sound resonance container, fix it in the sound resonance device, at a frequency of 60 Hz, adjust the acceleration to 100 g, keep the intensity at 30%, and maintain for 10 min to obtain negative electrode electrolyte powder. Through this process, Li 5.5 PS 4.5 Cl electrolyte particles are crushed and refined. Refer to Figure 1 , Figure (a) is a schematic diagram of the raw material, and Figure (b) is the result obtained after 10 min of sound resonance. Figure 1 In it, SED (Secondary Electron Detector, referring to the secondary electron detector), kV (abbreviation of Kilovolt, representing kiloelectron volts) is the voltage unit, WD represents the working distance, mm is the length unit, representing millimeters, μm is the length unit, representing micrometers, and FOV (abbreviation of Field of View, representing the field of view). At the same magnification, it can be clearly observed that the electrolyte particles are crushed and refined. The crushed and refined electrolyte particles are screened according to the set particle size to obtain three grades of negative electrode electrolyte powder.

[0082] (2) Add 5 g of Li with a size range of 10 μm - 15 μm, 3 g of Li with a size range of 3 μm - 5 μm, and 2 g of Li with a size range of 0.8 μm - 1.2 μm into the acoustic resonance device. 5.5 PS 4.5 Cl negative electrode electrolyte powder, with its total volume reaching 90% of the acoustic resonance device, is fixed in the acoustic resonance device. The acceleration is adjusted to 80 g and maintained for 5 min at a frequency of 60 Hz to obtain a dense Li 5.5 PS 4.5 Cl negative electrode solid electrolyte. It is found from the results that the Li 5.5 PS 4.5 Cl negative electrode solid electrolyte is relatively loose before acoustic resonance grading and becomes denser after acoustic resonance grading.

[0083] (3) Add 1 g of 50 - nm silicon powder as the negative electrode material and 1 g of the Li 5.5 PS 4.5 Cl negative electrode solid electrolyte obtained in step (2) into the acoustic resonance device. The acceleration is adjusted to 80 g and maintained for 5 min at a frequency of 60 Hz to obtain a modified negative electrode with nano - silicon - coated Li 5.5 PS 4.5 Cl. The coating result is as shown in Figure 2 . It can be seen that the overall coating effect is good, and the Li 5.5 PS 4.5 Cl negative electrode solid electrolyte is completely coated by silicon powder and is close to spherical. In the figure, k in 22k represents a thousand - fold, and ×22k represents a magnification of 22,000 times.

[0084] (4) Perform a constant - current charge - discharge performance test on a half - cell composed of this modified negative electrode electrode material and lithium indium.

[0085] Comparative Example 1

[0086] Perform a constant - current charge - discharge performance test on a half - cell composed of micron - sized silicon and lithium indium.

[0087] Compare the test results of Example 1 and Comparative Example 1. The comparison results are as shown in Figure 3 . It can be seen that both the rate performance and cycle stability of the coated half - cell can be stably improved. Figure 3 In, mAh / g represents the energy density, which is the unit of charge - specific capacity. mAh is milliamper - hour, and g is the gram of the battery.

[0088] Example 2

[0089] This example prepares a modified positive electrode and verifies the performance of the modified positive electrode, which specifically includes the following steps:

[0090] (1) Add 10 g of zirconia beads with a particle size of φ8 mm to a 15 mL acoustic resonance device. Fill the Li3InCl6 (abbreviated as LIC) electrolyte to 80% of the volume of the acoustic resonance container, fix it in the acoustic resonance device, adjust the acceleration to 100 g at a frequency of 60 Hz, and maintain the intensity at 30% for 10 min. During this process, the Li3InCl6 electrolyte particles are broken and refined to obtain the positive electrode electrolyte powder.

[0091] (2) Add 5 g of Li3InCl6 positive electrode electrolyte powder with a particle size of 10 μm - 15 μm, 3 g with a particle size of 3 μm - 5 μm, and 2 g with a particle size of 0.8 μm - 1.2 μm to the acoustic resonance device. The total volume reaches 90% of the acoustic resonance container, fix it in the acoustic resonance device, adjust the acceleration to 80 g at a frequency of 60 Hz and maintain for 5 min to obtain a dense Li3InCl6 positive electrode solid electrolyte.

[0092] (3) Add 1.4 g of Ni88 positive electrode material (LiNi 0.88 Co 0.09 Mn 0.03 O2), 0.1 g of conductive agent VGCF, and 0.5 g of Li3InCl6 positive electrode solid electrolyte to the acoustic resonance device. Adjust the acceleration to 90 g at a frequency of 60 Hz and maintain for 15 min. The intensity requirement during the acoustic resonance device process is > 20% to obtain a modified positive electrode.

[0093] (4) Combine the modified positive electrode battery material obtained in step (3) with lithium indium to form a half-cell and conduct voltage-capacity tests.

[0094] Comparative Example 2

[0095] Combine the Ni88 positive electrode material with lithium indium to form a half-cell and conduct voltage-capacity tests.

[0096] Comparative Example 3

[0097] Directly ball-mill 1.4 g of Ni88 positive electrode material (5 μm - 10 μm) and 0.5 g of Li3InCl6 electrolyte powder (0.5 μm - 1 μm) at a ball-milling speed of 300 rpm for 15 min to obtain a positive electrode. Combine this positive electrode with lithium indium to form a half-cell and conduct voltage-capacity tests.

[0098] Compare the first-cycle voltage-capacity test results of Example 2, Comparative Example 2, and Comparative Example 3. As Figure 4 , Figure 4 where V represents voltage. It can be seen from the figure that the test results of Example 2 and Comparative Example 3 are both better than those of the uncoated LIC positive electrode in Comparative Example 2, and the test results of the modified positive electrode obtained in Example 2 are the best, and the efficiency of the acoustic resonance method is higher.

[0099] The half-cells obtained in Example 2 and Comparative Example 3 were subjected to charge-discharge capacity tests, and the test results are as follows: Figure 5 As can be seen, after multiple cycles, the charge-discharge specific capacity of the modified positive electrode prepared by the acoustic resonance method is higher than that of the positive electrode prepared by the ball milling method.

[0100] Example 3

[0101] Prepare a sulfide separator using the Li 5.5 PS 4.5 Cl negative electrode solid electrolyte obtained in step (2) of Example 1. The specific process is as follows: Put 0.005 g of tetrafluoroethylene and 1 g of the Li 5.5 PS 4.5 Cl negative electrode solid electrolyte into a 15 mL acoustic resonance device, add 10 g of φ8 mm zirconia milling beads, adjust the acceleration to 60 g at a frequency of 60 Hz and maintain for 10 min to obtain a sulfide lumpy mixture, and roll press the sulfide lumpy mixture to obtain a complete sulfide separator with tetrafluoroethylene dispersed therein.

[0102] Use the Li3InCl6 positive electrode solid electrolyte obtained in step (2) of Example 2 to prepare a halide separator. The specific process is as follows: Put 0.005 g of tetrafluoroethylene and 1 g of the Li3InCl6 positive electrode solid electrolyte into a 15 mL acoustic resonance device, add 10 g of φ8 mm zirconia milling beads, adjust the acceleration to 60 g at a frequency of 60 Hz and maintain for 10 min to obtain a halide lumpy mixture, and roll press the halide lumpy mixture to obtain a complete halide separator with tetrafluoroethylene dispersed therein.

[0103] Directly compound the sulfide separator and the halide separator and then perform roll pressing treatment to obtain the final separator. The double-layer separator prepared in this example is dense and uniform.

[0104] Example 4

[0105] Assemble the modified negative electrode obtained in Example 1, the modified positive electrode obtained in Example 2, and the separator obtained in Example 3, with the sulfide separator on the side of the modified negative electrode and the halide separator on the side of the modified positive electrode to obtain a all-solid-state battery.

[0106] Comparative Example 4

[0107] Add 1.4 g of Ni88 positive electrode material, 0.1 g of conductive agent VGCF, and 0.5 g of LIC to the ball milling tank, and ball mill at a rotation speed of 300 rpm for 6 h to obtain a battery positive electrode; use micron Si as the negative electrode and a conventional LIC / Li 5.5 PS 4.5 Cl as the separator to prepare an all-solid-state battery. Here, the conventional LIC / Li 5.5 PS 4.5The Cl separator refers to a separator that is not prepared by the acoustic resonance method.

[0108] The all-solid-state battery obtained in Example 4 was subjected to charge and discharge cycling, and the all-solid-state battery obtained in Comparative Example 4 was subjected to charge and discharge cycling. The comparison results are as Figure 6 shown. Although Comparative Example 4 had a higher discharge capacity in the first cycle, its capacity retention rate and stability were inferior to those of Example 4 using the acoustic resonance method during subsequent cycling, and the acoustic resonance method significantly reduced the mixing time. The electrode material prepared by the acoustic resonance method has a uniform composition, enabling the final all-solid-state battery to have good electrochemical performance. The finally obtained electrode material has a better specific capacity compared to direct ball milling. Compared to the battery positive electrode prepared by ordinary powdering, the contact between the positive electrode particles and the electrolyte particles in the modified positive electrode is better, which is beneficial to the release of the battery specific capacity.

[0109] Example 5

[0110] (1) Add 10 g of zirconia beads with a particle size of φ8 mm to a 15 mL acoustic resonance device, fill the Li6PS5Cl electrolyte to 50% of the volume of the acoustic resonance container, fix it in the acoustic resonance device, adjust the acceleration to 100 g at a frequency of 60 Hz, maintain the intensity at 30%, and keep it for 10 min. Through this process, the Li6PS5Cl electrolyte particles are broken and refined to obtain negative electrode electrolyte powder.

[0111] (2) Add 5 g of 10 μm - 15 μm, 3 g of 3 μm - 5 μm, and 2 g of 0.8 μm - 1.2 μm Li6PS5Cl negative electrode electrolyte powder to the acoustic resonance device. The total volume reaches 90% of the acoustic resonance container, fix it in the acoustic resonance device, adjust the acceleration to 60 g at a frequency of 55 Hz and keep it for 10 min to obtain a dense Li6PS5Cl negative electrode solid electrolyte.

[0112] (3) Add 1 g of 50 nm silicon powder as the negative electrode material and 1 g of the Li6PS5Cl negative electrode solid electrolyte obtained in step (2) to the acoustic resonance device, adjust the acceleration to 80 g at a frequency of 55 Hz and keep it for 5 min to obtain a modified negative electrode.

[0113] (4) Add 10 g of zirconia beads with a particle size of φ8 mm to a 15 mL acoustic resonance device, fill the Li3InCl6 electrolyte to 50% of the volume of the acoustic resonance container, fix it in the acoustic resonance container, adjust the acceleration to 100 g at a frequency of 60 Hz, maintain the intensity at 30%, and keep it for 10 min. Through this process, the Li3InCl6 electrolyte particles are broken and refined to obtain positive electrode electrolyte powder.

[0114] (5) Add 5 g of Li3InCl6 cathode electrolyte powder with a particle size of 10 μm - 15 μm, 3 g of 3 μm - 5 μm, and 2 g of 0.8 μm - 1.2 μm into the acoustic resonance device. The total volume reaches 90% of the acoustic resonance device and is fixed in the device. Adjust the acceleration to 60 g at a frequency of 55 Hz and maintain it for 10 min to obtain a dense Li3InCl6 cathode solid electrolyte.

[0115] (6) Add 1.4 g of Ni88 cathode material and 0.5 g of Li3InCl6 cathode solid electrolyte into the acoustic resonance device. Adjust the acceleration to 80 g at a frequency of 55 Hz and maintain it for 5 min to obtain a coated cathode. Mix the coated cathode with 0.1 g of conductive agent VGCF by acoustic resonance method. Adjust the acceleration to 80 g at a frequency of 55 Hz and maintain it for 5 min to obtain a modified cathode.

[0116] (7) Use the Li6PS5Cl anode solid electrolyte prepared in step (2) to prepare a sulfide separator. The specific process is as follows: Put 0.005 g of tetrafluoroethylene and 1 g of the Li6PS5Cl anode solid electrolyte obtained in step (2) into a 15 mL acoustic resonance device, add 10 g of φ8 mm zirconia milling beads, adjust the acceleration to 80 g at a frequency of 30 Hz and maintain it for 20 min to obtain a lumpy mixture. Roll the lumpy mixture to obtain a complete sulfide separator with tetrafluoroethylene dispersed in it.

[0117] Use the Li3InCl6 cathode solid electrolyte prepared in step (5) to prepare a halide separator. The specific process is as follows: Put 0.005 g of tetrafluoroethylene and 1 g of the Li3InCl6 cathode solid electrolyte obtained in step (5) into a 15 mL acoustic resonance device, add 10 g of φ8 mm zirconia milling beads, adjust the acceleration to 80 g at a frequency of 30 Hz and maintain it for 20 min to obtain a lumpy mixture. Roll the lumpy mixture to obtain a complete halide separator with tetrafluoroethylene dispersed in it.

[0118] Roll and extrude the halide separator and the sulfide separator to obtain the final composite separator.

[0119] (8) Assemble the modified anode obtained in step (3), the modified cathode obtained in step (6), and the separator obtained in step (8). The sulfide separator is on the side of the modified anode, and the halide separator is on the side of the modified cathode to obtain a all-solid-state battery.

[0120] Perform charge-discharge performance tests on the all-solid-state battery prepared in Example 5. From Figure 7It can be seen that the rate performance is good and the long-cycle stability at 0.5C is good. 0.5C refers to the capacity factor of the battery energy storage system, which describes the relationship between the capacity of the battery energy storage system and its depth of discharge. For example, if the rated capacity of a battery is 200Ah, then 0.5C is equivalent to a charging or discharging rate of 100A, that is, the battery can be fully charged or discharged within 2 hours, and C is the definition method of the current magnitude.

[0121] The parameters and test performance of Examples 6 - 8 are described below through charts. Except for the parameter changes, the other parts not involved in the preparation processes of Examples 6 - 8 are the same as those of Example 5.

[0122] Table 1 Experimental Parameters of Examples 6 - 8

[0123]

[0124] Combined with Figures 8 - 10 It can be seen that for the all-solid-state battery prepared in Example 6, at 0.5C and a capacity of 100 mAh / g, after 200 cycles, the specific capacity can still remain at 99%. For the all-solid-state battery prepared in Example 7, at 0.5C and a capacity of 143 mAh / g, after 200 cycles, the specific capacity can still remain at 70%. For the all-solid-state battery prepared in Example 7, at 0.5C and a capacity of 123 mAh / g, after 200 cycles, the specific capacity can still remain at 84%. This shows that the all-solid-state batteries prepared in these examples have good cycle stability.

[0125] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an all-solid-state battery, characterized in that, It includes the following steps: S1. Respectively crush the positive electrolyte and the negative electrolyte by acoustic resonance method to obtain the positive electrolyte powder with M1 grade particle sizes and the negative electrolyte powder with M2 grade particle sizes, where both M1 and M2 are natural numbers greater than or equal to 2; the positive electrolyte is a halide, and the negative electrolyte is a sulfide; S2. Mix the positive electrolyte powders with N1 grade particle sizes and form a positive solid electrolyte by acoustic resonance method. Mix the negative electrolyte powders with N2 grade particle sizes and form a negative solid electrolyte by acoustic resonance method, where both N1 and N2 are natural numbers greater than or equal to 2; The positive electrolyte powders with N1 grade particle sizes and the negative electrolyte powders with N2 grade particle sizes both satisfy particle gradation; S3. Mix the positive solid electrolyte and the positive electrode material by acoustic resonance method to form a modified positive electrode in a coated form. Mix the negative solid electrolyte and the negative electrode material by acoustic resonance method to form a modified negative electrode in a coated form; The modified positive electrode is composed of a coating material and a material to be coated. When the coating material is the positive solid electrolyte, the material to be coated is the positive electrode material; when the coating material is the positive electrode material, the material to be coated is the positive solid electrolyte; The modified negative electrode is composed of a coating material and a material to be coated. When the coating material is the negative solid electrolyte, the material to be coated is the negative electrode material; when the coating material is the negative electrode material, the material to be coated is the negative solid electrolyte; S4. After combining the modified positive electrode, the separator and the modified negative electrode, a all-solid-state battery is obtained.

2. The preparation method of an all-solid-state battery according to claim 1, wherein In S3, the negative electrode material is nano-silicon, micro-silicon or lithium negative electrode, and the positive electrode material is a ternary nickel-based material or nickel cobalt manganese oxide.

3. The preparation method of an all-solid-state battery according to claim 1, characterized in that Both the coating material and the material to be coated are granular, and the particle size of the granular material to be coated is more than 100 times that of the granular coating material.

4. The preparation method of an all-solid-state battery according to claim 1, wherein, In S1, S2 and S3, the parameters controlled by the acoustic resonance method include frequency, acceleration and time.

5. The preparation method of an all-solid-state battery according to claim 1, characterized in that, In S4, the separator is a double-layer separator, the double-layer separator is respectively a halide separator and a sulfide separator, and both the halide separator and the sulfide separator are obtained by acoustic resonance method.

6. The preparation method of an all-solid-state battery according to claim 5, wherein The specific process for preparing the separator is as follows: Mix the negative solid electrolyte and the binder by acoustic resonance method to obtain a sulfide massive mixture, extrude the sulfide massive mixture into a film to obtain a sulfide separator; Mix the positive solid electrolyte and the binder by acoustic resonance method to prepare a halide massive mixture, extrude the halide massive mixture into a film to obtain a halide separator; Co-extrude and compound the sulfide separator and the halide separator to obtain a double-layer separator.

7. The preparation method of an all-solid-state battery according to claim 6, wherein, In the sulfide massive mixture, the mass of the binder is 0.5%-3% of the mass of the negative solid electrolyte; in the halide massive mixture, the mass of the binder is 0.5%-3% of the mass of the positive solid electrolyte.

8. A all-solid-state battery prepared by the preparation method according to any one of claims 1-7, characterized in that, It includes a modified positive electrode, a separator and a modified negative electrode.

Images