High-nickel elastic composite positive electrode of solid-state battery, preparation method of high-nickel elastic composite positive electrode and battery
By introducing an elastic ion conductor into the positive electrode of a solid-state battery, the problem of widening gaps between active particles and electrolyte particles is solved, achieving efficient ion transport and long lifespan performance of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN UNIV
- Filing Date
- 2026-01-28
- Publication Date
- 2026-04-24
AI Technical Summary
The micron-sized gaps between active particles and electrolyte particles in the positive electrode of a solid-state battery expand during charging and discharging, leading to increased ionic impedance and severely affecting the battery's rate performance and cycle life.
Introducing a flexible ion conductor into the cathode of a solid-state battery allows for adaptive adjustment of its morphology through changes in material volume, filling voids and maintaining close contact between particles, thus constructing a continuous ion transport path.
It effectively reduces ion transport impedance, thereby improving the rate performance and cycle life of solid-state batteries.
Smart Images
Figure CN121922641A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of batteries, and more specifically, to a high-nickel elastic composite cathode for solid-state batteries, its preparation method, and the battery itself. Background Technology
[0002] As the new energy industry continues to demand higher safety and energy density from energy storage devices, solid-state batteries, with their outstanding safety performance and superior energy density, have become a core research and development direction for next-generation energy storage technologies. While solid-state batteries have solved the problems of electrolyte leakage and thermal runaway compared to traditional liquid lithium batteries, a key bottleneck exists in the cathode: the micron-sized gaps between active and electrolyte particles expand with charge-discharge volume changes, significantly increasing ionic impedance and severely limiting battery rate performance and cycle life. Therefore, constructing high-performance solid-state batteries to address the problem of poor physical solid-state contact is a current challenge of great interest to those skilled in the art. Summary of the Invention
[0003] The purpose of this application is to provide a high-nickel elastic composite cathode for solid-state batteries, a method for preparing the same, and the battery itself, in order to improve the above-mentioned problems.
[0004] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In a first aspect, embodiments of this application provide a method for preparing a high-nickel elastic composite cathode for solid-state batteries, the method comprising the following steps: Step 1: Disperse PVDF in an organic solvent at a mass ratio of 0.032-0.04 and stir until completely dissolved to obtain a PVDF solution. Step 2: Disperse the lithium lanthanum zirconium tantalum oxide particles in the organic solvent at a mass ratio of 0.034-0.11, and then perform ultrasonic treatment to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid. Step 3: According to the volume ratio of lithium lanthanum zirconium tantalum oxide turbid solution to PVDF solution, the lithium lanthanum zirconium tantalum oxide turbid solution prepared in step 2 is poured into the solution obtained by the PVDF solution prepared in step 1, and stirred to obtain electrolyte composite slurry. Step 5: According to the mass ratio of composite powder to slurry of 0.25, add the composite powder of high nickel cathode and conductive carbon to the electrolyte slurry prepared in step 3, stir to obtain cathode slurry, coat the cathode slurry onto aluminum foil, and dry to obtain high nickel composite cathode sheet.
[0005] Secondly, embodiments of this application provide a high-nickel elastic composite cathode, which is a composite cathode prepared by the above-described method for preparing a high-nickel elastic composite cathode for solid-state batteries.
[0006] Secondly, embodiments of this application provide a battery comprising the aforementioned high-nickel elastic composite positive electrode.
[0007] Compared to existing technologies, the present application provides a high-nickel elastic composite positive electrode for solid-state batteries, its preparation method, and the battery itself. The method involves dispersing PVDF in an organic solvent and stirring until completely dissolved to obtain a PVDF solution; dispersing lithium lanthanum zirconium tantalum oxide particles in an organic solvent and ultrasonically treating them to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid; pouring the lithium lanthanum zirconium tantalum oxide turbid liquid into the solution obtained in the PVDF step and stirring to obtain an electrolyte composite slurry; adding a high-nickel positive electrode and conductive carbon composite powder to the electrolyte slurry at a composite powder to slurry mass ratio of 0.25 and stirring to obtain a positive electrode slurry; coating the positive electrode slurry onto an aluminum foil and drying it to obtain a high-nickel composite positive electrode sheet. By introducing a flexible ion conductor into the cathode of a solid-state battery, and adaptively adjusting its shape according to the material volume change during charge-discharge cycles, it fills the gaps through its own deformation, continuously maintaining close contact between particles. This can ensure particle contact while constructing a continuous ion transport path through the cathode, fundamentally reducing ion transport impedance. By improving the ion transport environment inside the cathode, the rate performance and cycle life of solid-state batteries are effectively improved.
[0008] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0009] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0010] Figure 1 A schematic diagram of lithium lanthanum zirconium tantalum oxide powder after being ground by the ball milling process provided by the present invention.
[0011] Figure 2 SEM image of the elastic filler provided by the present invention.
[0012] Figure 3 Nanoindentation test pattern of the high-nickel composite cathode corresponding to Example 3 of the present invention.
[0013] Figure 4 The image shows the SEM image of the high-nickel composite cathode corresponding to Example 3 of the present invention.
[0014] Figure 5 The SEM image of the high-nickel cathode corresponding to the comparative example provided by this invention. Detailed Implementation
[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0016] Solid-state batteries with high-nickel cathodes have significant advantages, possessing a high theoretical discharge capacity of 300-350 mAh / g. When matched with solid electrolytes, they can enable battery energy density to exceed 400 Wh / kg, meeting the needs of long-range new energy vehicles and high-density energy storage in high-end energy storage. However, there are micron-level gaps between the high-nickel cathode and electrolyte particles, which will further expand during cycling, leading to a sharp increase in ion transport impedance. This severely restricts the battery's rate performance and cycle life, limiting its application.
[0017] To overcome the aforementioned problems, this invention provides a method for preparing a high-nickel elastic composite cathode for solid-state batteries. This method involves introducing an elastic ion conductor into the solid-state battery cathode, which adaptively adjusts its morphology according to material volume changes during charge-discharge cycles, continuously maintaining close contact between particles. This ensures particle contact while constructing a continuous ion transport path throughout the cathode, fundamentally reducing ion transport impedance. By improving the internal ion transport environment of the cathode, the rate performance and cycle life of the solid-state battery are effectively enhanced. Furthermore, the method for preparing the high-nickel elastic composite cathode for solid-state batteries provided by this invention is simple to operate, low in cost, environmentally friendly, highly reproducible, produces stable product quality, and is suitable for large-scale industrial production.
[0018] Please refer to the following text: The method for preparing a high-nickel elastic composite cathode for solid-state batteries provided by this invention includes the following steps: Step 1: Disperse PVDF in an organic solvent at a mass ratio of 0.032-0.04 and stir until completely dissolved to obtain a PVDF solution.
[0019] The ratio of polyvinylidene fluoride (PVDF) mass to organic solvent mass ranges from 0.032 to 0.04. Preferably, the ratio is 0.04. If the ratio is too high, the PVDF solution will have poor fluidity. If the ratio is too low, the filler will exhibit stratification and agglomeration.
[0020] The PVDF in each gram of PVDF solution prepared in step 1 has a molecular weight of 500,000-700,000. PVDF with this molecular weight has good adhesive properties.
[0021] Step 2: Disperse the lithium lanthanum zirconium tantalum oxide particles in an organic solvent at a mass ratio of 0.034-0.11, and then perform ultrasonic treatment to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid.
[0022] The mass ratio of lithium lanthanum zirconium tantalum oxide particles to organic solvent ranges from 0.034 to 0.11, and preferably, this ratio can be 0.04. Adding excessive amounts of lithium lanthanum zirconium tantalum oxide particles does not improve the lithium-ion concentration inside the cathode.
[0023] The ultrasonic treatment at room temperature lasts for 10-15 minutes to obtain a lithium lanthanum zirconium tantalum oxide suspension with a concentration of 5-50 g / L. Ultrasonic treatment prevents particles from settling to the bottom, resulting in a more uniform distribution.
[0024] Step 3: Pour the lithium lanthanum zirconium tantalum oxide turbid solution prepared in Step 2 into the solution obtained from the PVDF solution prepared in Step 1, according to a volume ratio of 1:1, and stir to obtain an electrolyte composite slurry.
[0025] In step three, the mixture is stirred at 300-500 rpm for 12-24 hours to obtain the electrolyte composite slurry.
[0026] Step 5: According to the mass ratio of composite powder to slurry of 0.25, add the composite powder of high nickel cathode and conductive carbon to the electrolyte slurry prepared in step 3, stir to obtain cathode slurry, coat the cathode slurry onto aluminum foil, and dry to obtain high nickel composite cathode sheet.
[0027] It can be dried in a vacuum drying oven for 6-24 hours at a temperature of 60-100℃. In step five, it is stirred at a speed of 500-600 rpm for 0.5 hours to obtain the positive electrode composite slurry.
[0028] This invention provides a method for preparing a high-nickel elastic composite cathode for solid-state batteries. The method involves introducing an elastic ion conductor into the cathode of a solid-state battery, which adaptively adjusts its shape according to the volume change of the material during charge-discharge cycles. By filling the gaps through its own deformation, it continuously maintains close contact between particles, thereby ensuring particle contact while constructing a continuous ion transport path through the cathode, thus reducing ion transport impedance at its source. By improving the ion transport environment inside the cathode, the method effectively enhances the rate performance and cycle life of solid-state batteries.
[0029] Optionally, prior to step five, the method for preparing a high-nickel elastic composite cathode for solid-state batteries further includes: Step 4: Grind the high-nickel cathode and conductive carbon at a mass ratio of 10-20 to obtain composite powder.
[0030] Among them, the nickel content of high-nickel materials exceeds 80%, and the high-nickel materials can be any one of NCM523, NCM622, and NCM811. In step four, grind until the two materials are evenly dispersed; the grinding time can be 15-30 minutes.
[0031] The conductive carbon is any one of acetylene black, Ketjen black, or Super P.
[0032] In this invention, the organic solvent is a highly polar aprotic solvent, which can be any one of N,N-dimethylformamide, N-methylpyrrolidone, and anhydrous acetonitrile.
[0033] In this invention, the lithium lanthanum zirconium tantalum oxide particles are obtained by mechanically ball milling lithium lanthanum zirconium tantalum oxide particles.
[0034] The diameter of lithium lanthanum zirconium tantalum oxide particles is 1-10 μm.
[0035] Lithium lanthanum zirconium tantalum oxide particles are too small and are prone to agglomeration in PVDF solutions.
[0036] Please refer to Figure 1 , Figure 1 This is a schematic diagram of lithium lanthanum zirconium tantalum oxide powder after being ground using the ball milling process provided by the present invention. As can be seen from the figure, the powder is mainly in the form of particles, with a particle size between 1 and 10 μm.
[0037] This invention also provides a high-nickel elastic composite cathode. It should be noted that, based on the aforementioned method for preparing a high-nickel elastic composite cathode for solid-state batteries, a cathode sheet can be obtained, which is the high-nickel elastic composite cathode.
[0038] This invention also provides a battery, which can be a solid-state lithium metal battery, comprising the aforementioned high-nickel elastic composite positive electrode. Specifically, the battery comprises a high-nickel elastic composite positive electrode, a negative electrode, and a solid electrolyte.
[0039] The composite solid electrolyte is located between the high-nickel elastic composite positive electrode and the lithium metal negative electrode, and the solid electrolyte is in contact with both the high-nickel elastic composite positive electrode and the lithium metal negative electrode respectively.
[0040] Optionally, a high-nickel elastic composite positive electrode, a solid electrolyte, a lithium sheet, a gasket, and a spring are placed into the positive electrode shell, and finally the negative electrode shell is covered. After being placed on a hydraulic press and pressed, the solid lithium metal battery is obtained.
[0041] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0042] Example 1 Step 1: Disperse PVDF in an organic solvent at a mass ratio of 0.04 and stir until completely dissolved to obtain a PVDF solution; Step 2: Disperse the lithium lanthanum zirconium tantalum oxide particles in an organic solvent at a mass ratio of 0.0347 and perform ultrasonic treatment at room temperature to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid.
[0043] Step 3: Pour the lithium lanthanum zirconium tantalum oxygen turbid solution into the solution obtained in Step 1 and stir to obtain an electrolyte composite slurry.
[0044] Step 4: Grind the high-nickel cathode and conductive carbon at a mass ratio of 10 to obtain composite powder.
[0045] Step 5: Add the composite powder to the electrolyte slurry at a mass ratio of 0.25 (composite powder to slurry) and stir to obtain the positive electrode slurry; coat the positive electrode slurry onto aluminum foil and dry it in a vacuum drying oven for 24 hours to obtain a high-nickel composite positive electrode sheet.
[0046] Example 2 Step 1: Disperse PVDF in an organic solvent at a mass ratio of 0.04 and stir until completely dissolved to obtain a PVDF solution; Step 2: Disperse the lithium lanthanum zirconium tantalum oxide particles in an organic solvent at a mass ratio of 0.091 and perform ultrasonic treatment at room temperature to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid.
[0047] Step 3: Pour the lithium lanthanum zirconium tantalum oxygen turbid solution into the solution obtained in Step 1 and stir to obtain an electrolyte composite slurry.
[0048] Step 4: Grind the high-nickel cathode and conductive carbon at a mass ratio of 16 to obtain composite powder.
[0049] Step 5: Add the composite powder to the electrolyte slurry at a mass ratio of 0.25 (composite powder to slurry) and stir to obtain the positive electrode slurry; coat the positive electrode slurry onto aluminum foil and dry it in a vacuum drying oven for 24 hours to obtain a high-nickel composite positive electrode sheet.
[0050] Example 3 Step 1: Disperse PVDF in an organic solvent at a mass ratio of 0.04 and stir until completely dissolved to obtain a PVDF solution; Step 2: Disperse the lithium lanthanum zirconium tantalum oxide particles in an organic solvent at a mass ratio of 0.11 and perform ultrasonic treatment at room temperature to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid.
[0051] Step 3: Pour the lithium lanthanum zirconium tantalum oxygen turbid solution into the solution obtained in Step 1 and stir to obtain an electrolyte composite slurry.
[0052] Step 4: Grind the high-nickel cathode and conductive carbon at a mass ratio of 20 to obtain composite powder.
[0053] Step 5: Add the composite powder to the electrolyte slurry at a mass ratio of 0.25 (composite powder to slurry) and stir to obtain the positive electrode slurry; coat the positive electrode slurry onto aluminum foil and dry it in a vacuum drying oven for 24 hours to obtain a high-nickel composite positive electrode sheet.
[0054] Example 4 Step 1: Disperse PVDF in an organic solvent at a mass ratio of 0.032 and stir until completely dissolved to obtain a PVDF solution; Step 2: Disperse the lithium lanthanum zirconium tantalum oxide particles in an organic solvent at a mass ratio of 0.11 and perform ultrasonic treatment at room temperature to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid.
[0055] Step 3: Pour the lithium lanthanum zirconium tantalum oxygen turbid solution into the solution obtained in Step 1 and stir to obtain an electrolyte composite slurry.
[0056] Step 4: Grind the high-nickel cathode and conductive carbon at a mass ratio of 16 to obtain composite powder.
[0057] Step 5: Add the composite powder to the electrolyte slurry at a mass ratio of 0.25 (composite powder to slurry) and stir to obtain the positive electrode slurry; coat the positive electrode slurry onto aluminum foil and dry it in a vacuum drying oven for 24 hours to obtain a high-nickel composite positive electrode sheet.
[0058] Comparative Example Step 1: Disperse PVDF in an organic solvent at a mass ratio of 0.04 and stir until completely dissolved to obtain a PVDF solution; Step 2: Grind the high-nickel cathode and conductive carbon at a mass ratio of 10 to obtain composite powder.
[0059] Step 3: Add the composite powder to the PVDF solution at a mass ratio of 0.25 (composite powder to slurry) and stir to obtain the positive electrode slurry; coat the positive electrode slurry onto aluminum foil and dry it in a vacuum drying oven for 24 hours to obtain a high-nickel positive electrode sheet.
[0060] The obtained positive electrode sheet, solid electrolyte, lithium sheet, gasket, and spring sheet are sequentially placed into the positive electrode shell, and finally the negative electrode shell is covered. After being pressed at 0.65MPa on a hydraulic press, it is removed to obtain a high-nickel positive electrode / lithium metal battery, also known as a solid lithium metal battery.
[0061] The battery performance of the coin cells corresponding to the examples and comparative examples was tested using a battery test cabinet. The voltage range during the charge and discharge process was set to 2.8V-4.3V. Please refer to Table 1 below, which is a comparison table of the discharge specific capacity of the examples and comparative examples.
[0062] Please refer to Figure 2 , Figure 2 SEM image of the elastic filler provided by the present invention. Figure 2 and Figure 1 The difference lies in the fact that polymer-coated lithium lanthanum zirconium tantalum oxide particles improve interfacial contact and enhance ion conductivity.
[0063] Please refer to Figure 3 , Figure 3 The nanoindentation test pattern of the high-nickel composite cathode corresponding to Example 3 of the present invention. The material of Example 3 exhibits superior mechanical properties at the nanoscale, including higher hardness, stiffness, and better elastic recovery, which generally means that it has a denser microstructure or stronger interfacial bonding.
[0064] Please refer to Figure 4 and Figure 5 , Figure 4 The image shows the SEM image of the high-nickel composite cathode corresponding to Example 3 of the present invention. Figure 5 The SEM image of the high-nickel cathode corresponding to the comparative example provided by this invention. Clearly, compared to... Figure 5 The gap shown Figure 4 The gaps were filled by deformation.
[0065] In summary, this invention provides a high-nickel elastic composite cathode for solid-state batteries, its preparation method, and the battery itself. PVDF is dispersed in an organic solvent and stirred until completely dissolved to obtain a PVDF solution. Lithium lanthanum zirconium tantalum oxide particles are dispersed in the organic solvent and ultrasonically treated to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid. The lithium lanthanum zirconium tantalum oxide turbid liquid is poured into the solution obtained in the PVDF step and stirred to obtain an electrolyte composite slurry. At a composite powder to slurry mass ratio of 0.25, a high-nickel cathode and conductive carbon composite powder are added to the electrolyte slurry and stirred to obtain a cathode slurry. The cathode slurry is then coated onto aluminum foil and dried to obtain a high-nickel composite cathode sheet. By introducing an elastic ion conductor into the solid-state battery cathode, and allowing it to adaptively adjust its shape according to material volume changes during charge-discharge cycles, the cathode fills gaps through its own deformation, continuously maintaining close contact between particles. This ensures particle contact while constructing a continuous ion transport path throughout the cathode, fundamentally reducing ion transport impedance. By improving the internal ion transport environment of the cathode, the rate performance and cycle life of the solid-state battery are effectively improved.
[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing a high-nickel elastic composite cathode for solid-state batteries, characterized in that, The method includes the following steps: Step 1: Disperse PVDF in an organic solvent at a mass ratio of 0.032-0.04 and stir until completely dissolved to obtain a PVDF solution. Step 2: Disperse the lithium lanthanum zirconium tantalum oxide particles in the organic solvent at a mass ratio of 0.034-0.11, and then perform ultrasonic treatment to obtain a lithium lanthanum zirconium tantalum oxide turbid liquid. Step 3: According to the volume ratio of lithium lanthanum zirconium tantalum oxide turbid solution to PVDF solution, the lithium lanthanum zirconium tantalum oxide turbid solution prepared in step 2 is poured into the solution obtained by the PVDF solution prepared in step 1, and stirred to obtain electrolyte composite slurry. Step 5: According to the mass ratio of composite powder to slurry of 0.25, add the composite powder of high nickel cathode and conductive carbon to the electrolyte slurry prepared in step 3, stir to obtain cathode slurry, coat the cathode slurry onto aluminum foil, and dry to obtain high nickel composite cathode sheet.
2. The method for preparing a high-nickel elastic composite cathode for solid-state batteries as described in claim 1, characterized in that, Prior to step five, the method further includes: Step 4: Grind the high-nickel cathode and conductive carbon at a mass ratio of 10-20 to obtain composite powder.
3. The method for preparing a high-nickel elastic composite cathode for solid-state batteries as described in claim 2, characterized in that, The conductive carbon is any one of acetylene black, Ketjen black, or Super P.
4. The method for preparing a high-nickel elastic composite cathode for solid-state batteries as described in claim 1, characterized in that, The organic solvent is any one of N,N-dimethylformamide, N-methylpyrrolidone, and anhydrous acetonitrile.
5. The method for preparing a high-nickel elastic composite cathode for solid-state batteries as described in claim 1, characterized in that, The diameter of the lithium lanthanum zirconium tantalum oxide particles is 1-10 μm.
6. The method for preparing a high-nickel elastic composite cathode for solid-state batteries as described in claim 5, characterized in that, The lithium lanthanum zirconium tantalum oxide particles are obtained by mechanically ball milling lithium lanthanum zirconium tantalum oxide particles.
7. The method for preparing a high-nickel elastic composite cathode for solid-state batteries as described in claim 1, characterized in that, The molecular weight of PVDF in each gram of PVDF solution prepared in step 1 is 500,000-700,000.
8. A high-nickel elastic composite positive electrode, characterized in that, The composite cathode is prepared by the method for preparing a high-nickel elastic composite cathode for solid-state batteries according to any one of claims 1-7.
9. A battery, characterized in that, The battery includes the high-nickel elastic composite positive electrode as described in claim 8.