Nanometer plate-shaped all-solid-state lithium-rich manganese-based positive electrode material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a nano-plate-shaped all-solid-state lithium-rich manganese-based positive electrode material as well as a preparation method and application thereof. Comprising the following steps: (1) sintering a nickel manganese hydroxide precursor for the first time to obtain pre-sintered nickel manganese hydroxide; (2) uniformly mixing the pre-sintered nickel manganese hydroxide with a lithium salt, carrying out secondary sintering, continuously heating, and carrying out third sintering, so as to obtain high-temperature powder; and carrying out quenching treatment on the high-temperature powder to obtain the nano-plate-shaped all-solid-state lithium-rich manganese-based positive electrode material. The prepared nano-plate-shaped all-solid-state lithium-rich manganese-based positive electrode material has relatively good consistency and stability, and has the advantages of high capacity, high first efficiency, good cycle performance and the like in an all-solid-state battery, and the preparation method has the advantages of simple process, low cost, high production efficiency and the like.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, its preparation method, and its application. Background Technology

[0002] All-solid-state lithium batteries fundamentally solve the thermal runaway risk of traditional lithium-ion batteries because they use non-flammable inorganic solid electrolytes, and have extremely high intrinsic safety. At the same time, their theoretical energy density far exceeds that of existing systems, and they are recognized as the strategic development direction of the next generation of energy storage technology.

[0003] Lithium-rich manganese-based cathode materials (xLi₂MnO₃·(1-x)LiMO₂) are one of the key cathode materials for achieving this high energy density target, with a theoretical specific capacity exceeding 250 mAh / g. However, the industrial application of this material faces severe challenges: First, there is a significant irreversible capacity loss during the initial charge-discharge process, resulting in a low initial coulombic efficiency; second, during long-term cycling, the material structure undergoes continuous degradation, leading to significant voltage and capacity decay and insufficient cycle stability. Furthermore, in the unique solid-solid interface of all-solid batteries, the traditional cathode material has a small contact area and high interfacial impedance with the solid electrolyte, severely restricting the efficient transport of lithium ions and further amplifying the aforementioned problems, becoming a core bottleneck restricting breakthroughs in the performance of all-solid batteries.

[0004] Currently, to reduce the huge solid-solid interface impedance, researchers are committed to developing small-particle or nano-sized lithium-rich cathode materials to increase the contact area with solid electrolytes. Among them, micron-sized polycrystalline cathodes formed by the agglomeration of primary nanocrystals have become the mainstream technical route. However, the current conventional small-particle polycrystalline structure has significant shortcomings: (1) the primary nanocrystals inside are mostly simple physical stacks, lacking strong connections. During electrode preparation and cycling, the particles are prone to loosening or even breaking, leading to contact failure; (2) this loose internal structure makes it difficult to form continuous and efficient ion / electron transport channels, limiting rate performance; (3) the random stacking of primary nanocrystals makes their contact with solid electrolytes still limited and unstable, failing to fully realize the potential of nano-sizing. In view of this, the present invention provides a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, its preparation method and application. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, its preparation method, and its application. The aim is to design a micron-scale polycrystalline cathode material composed of two-dimensional nanoplate primary particles that are cross-linked and densely grown in three-dimensional space, suitable for all-solid-state batteries.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, a method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following steps: (1) The nickel-manganese hydroxide precursor was sintered for the first time to obtain pre-sintered nickel-manganese hydroxide; (2) The pre-sintered nickel manganese hydroxide is mixed evenly with lithium salt, and then sintered a second time. The temperature is then raised to a third time to obtain high-temperature powder. The high-temperature powder is then quenched to obtain nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, the chemical formula of the nickel-manganese hydroxide precursor in step (1) is Ni a Mn b (OH)2; where 0.2≤a≤0.45, 0.55≤b≤0.8, a+b=1.

[0009] Furthermore, the conditions for the first sintering in step (1) are: heating to 300-700℃ at a heating rate of 2-10℃ / min and then holding at that temperature for 4-15 h.

[0010] Furthermore, the lithium salt mentioned in step (2) includes at least one of lithium hydroxide, lithium carbonate, lithium chloride, and lithium nitrate.

[0011] Furthermore, the molar ratio of the pre-sintered nickel manganese hydroxide to the lithium salt in step (2) is 1:1.15~1.55.

[0012] Furthermore, the conditions for the second sintering in step (2) are: heating to 400-600℃ at a heating rate of 2-10℃ / min and then holding at that temperature for 2-10 h. The conditions for the third sintering in step (2) are: heating to 700-950℃ at a heating rate of 2-10℃ / min and then holding at that temperature for 8-18 hours.

[0013] Furthermore, the specific method for quenching the high-temperature powder is as follows: the high-temperature powder is poured onto a metal plate or stone slab with a pre-cooling temperature of 30~150℃, and then another metal plate or stone slab of the same temperature is placed on top of the high-temperature powder, allowing it to cool naturally to room temperature. The metal plate or stone slab may include diamond plate, copper plate, silver plate, or aluminum plate, etc.

[0014] Secondly, a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material is prepared by the aforementioned preparation method.

[0015] Furthermore, the chemical formula of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material is Li. x Ni y Mn z O2; where 1.1≤x≤1.5, 0.2≤y≤0.5, 0.4≤z≤0.8.

[0016] Thirdly, the application of a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, wherein the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material described herein is used in the preparation of all-solid-state lithium batteries.

[0017] The beneficial effects of this invention are: (1) The cross-linking between the primary nanoplates of the nanoplate-based lithium-rich manganese cathode material prepared by the present invention forms a stable three-dimensional skeleton, which greatly enhances the mechanical strength of the secondary particles, effectively buffers cyclic stress, prevents particle pulverization, and thus improves cycle life.

[0018] (2) The nanoplate-shaped lithium-rich manganese-based cathode material prepared by the present invention has a fast ion transport network that runs through the interior of the particles by cross-linking the nanoplates, which significantly reduces the diffusion resistance of lithium ions in the solid phase and improves the rate performance.

[0019] (3) The nanoplate-shaped lithium-rich manganese-based cathode material structure prepared by the present invention enables the micron-sized particles to achieve a nano-interface inside, which can form a huge and stable three-dimensional interpenetrating contact interface with the solid electrolyte, thereby greatly reducing the interface impedance and ensuring the full utilization of the active material.

[0020] (4) The preparation process of the present invention is simple, the reaction is easy to control, the equipment requirements are low, and the production efficiency is high. The prepared products have good consistency. Attached Figure Description

[0021] Figure 1 The image shows the XRD pattern of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 1 of this invention. Figure 2 This is a SEM image of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 1 of this invention; Figure 3 The first charge-discharge curve of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 1 of this invention is shown. Figure 4 This is a SEM image of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 2 of this invention; Figure 5 This is a SEM image of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 3 of this invention; Figure 6The image shows the XRD pattern of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 4 of this invention. Figure 7 This is a SEM image of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 4 of this invention; Figure 8 This is the first charge-discharge curve of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 4 of the present invention; Figure 9 This is a SEM image of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 5 of this invention; Figure 10 This is a SEM image of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 6 of this invention; Figure 11 This is a SEM image of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 7 of this invention; Figure 12 This is a SEM image of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared in Example 8 of this invention; Figure 13 This is a SEM image of the all-solid-state lithium-rich manganese-based cathode material prepared in Comparative Example 1 of this invention; Figure 14 This is a SEM image of the all-solid-state lithium-rich manganese-based cathode material prepared in Comparative Example 2 of this invention; Figure 15 The first charge-discharge curves of Embodiments 1, 4, 6 and Comparative Example 1 of the present invention are shown below. Figure 16 The diagram shows the cyclic performance of Embodiments 1, 4, 6 and Comparative Example 1 of the present invention. Detailed Implementation

[0022] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0023] This embodiment relates to a method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, including the following steps: (1) The nickel-manganese hydroxide precursor was sintered for the first time to obtain pre-sintered nickel-manganese hydroxide; (2) The pre-sintered nickel manganese hydroxide is mixed evenly with lithium salt, and then sintered a second time. The temperature is then raised to a third time to obtain high-temperature powder. The high-temperature powder is then quenched to obtain nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0024] Preferably, in step (1) of this embodiment, the chemical formula of the nickel-manganese hydroxide precursor is Ni a Mn b (OH)2; where 0.2≤a≤0.45, 0.55≤b≤0.8, a+b=1.

[0025] Preferably, the conditions for the first sintering in step (1) of this embodiment are: heating to 300-700°C at a heating rate of 2-10°C / min and holding for 4-15 h, for example, heating to 600°C at a heating rate of 5°C / min and holding for 6 h, heating to 300°C at a heating rate of 2°C / min and holding for 15 h, heating to 500°C at a heating rate of 8°C / min and holding for 12 h, etc.

[0026] Preferably, the lithium salt in step (2) of this embodiment includes at least one of lithium hydroxide, lithium carbonate, lithium chloride, and lithium nitrate.

[0027] The molar ratio of the pre-sintered nickel manganese hydroxide to the lithium salt in step (2) is 1:1.15~1.55, for example 1:1.2, 1:1.25, 1:1.3, 1:1.35, 1:1.4, etc.

[0028] Preferably, the conditions for the second sintering in step (2) of this embodiment are: heating to 400-600℃ at a heating rate of 2-10℃ / min and holding for 2-10 h; the conditions for the third sintering in step (2) are: heating to 700-950℃ at a heating rate of 2-10℃ / min and holding for 8-18 h; for example, heating to 475℃ at a heating rate of 4℃ / min at room temperature and holding for 4 h, then heating to 850℃ at a heating rate of 5℃ / min and holding for 16 h; heating to 450℃ at a heating rate of 10℃ / min at room temperature and holding for 6 h, then heating to 925℃ at a heating rate of 2℃ / min and holding for 8 h; heating to 500℃ at a heating rate of 5℃ / min at room temperature and holding for 4 h, then heating to 850℃ at a heating rate of 5℃ / min and holding for 18 h. h etc.

[0029] Preferably, the specific method for quenching the high-temperature powder in this embodiment is as follows: the high-temperature powder is poured onto a metal plate or stone plate with a pre-cooling temperature of 30~150℃, and then another metal plate or stone plate of the same temperature is placed on top of the high-temperature powder, allowing it to cool naturally to room temperature. The metal plate or stone plate may include diamond plate, copper plate, silver plate, or aluminum plate, etc.

[0030] Specifically, a method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following specific steps: (1) The nickel-manganese hydroxide precursor was placed in a muffle furnace with air introduced for pre-sintering. The temperature was raised to 300-700℃ at a heating rate of 2-10℃ / min and held for 4-15 h to obtain pre-sintered nickel-manganese hydroxide. (2) After uniformly mixing the pre-sintered nickel manganese hydroxide with a certain molar mass of lithium salt, the mixture is placed in a muffle furnace with air introduced. The temperature is raised to 400-600℃ at a heating rate of 2-10℃ / min and held for 2-10 h. Then, the temperature is raised to 700-950℃ at a heating rate of 2-10℃ / min and held for 8-18 h. After the holding period, the high-temperature powder is quickly taken out of the furnace and poured onto a copper plate with a pre-cooling temperature of 30-150℃. Then, another copper plate is immediately placed on top and the powder product is collected after it cools naturally to room temperature. This yields a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0031] This embodiment also relates to a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, which is prepared by the aforementioned preparation method.

[0032] Preferably, the chemical formula of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material in this embodiment is Li. x Ni y Mn z O2; where 1.1≤x≤1.5, 0.2≤y≤0.5, 0.4≤z≤0.8.

[0033] This embodiment also relates to the application of a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, which is used in the preparation of all-solid-state lithium batteries.

[0034] The following description uses specific examples to further illustrate the point.

[0035] Example 1 This embodiment relates to a method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, including the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the temperature to 600°C at a heating rate of 5°C / min and hold for 6 h to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide and lithium hydroxide were mixed at a molar ratio of 1:1.35. 6.27 g of lithium hydroxide was added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 400°C at a heating rate of 5°C / min at room temperature and held for 5 h. Then, the temperature was increased to 950°C at a heating rate of 2°C / min and held for 15 h. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto a copper plate with a pre-cooling temperature of 80°C. Another copper plate was immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0036] Example 2 A method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the temperature to 500°C at a heating rate of 8°C / min and hold for 12 h to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide and lithium hydroxide were mixed at a molar ratio of 1:1.25. 5.81 g of lithium hydroxide was added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 500°C at a heating rate of 10°C / min at room temperature and held for 8 hours. Then, the temperature was increased to 900°C at a heating rate of 5°C / min and held for 12 hours. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto a diamond plate with a pre-cooling temperature of 100°C. Another diamond plate was immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0037] Example 3 A method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the mixture to 450°C at a heating rate of 8°C / min and hold it for 6 hours to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide was mixed with lithium carbonate / lithium hydroxide at a molar ratio of 1:1.4 (5:5). 2.87 g of lithium carbonate and 3.25 g of lithium hydroxide were added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 600°C at a heating rate of 4°C / min at room temperature and held for 2 h. Then, the temperature was increased to 800°C at a heating rate of 2°C / min and held for 8 h. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto a copper plate with a pre-cooling temperature of 40°C. Another copper plate was immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0038] Example 4 A method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the furnace to 300°C at a heating rate of 2°C / min and hold for 15 h to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide and lithium carbonate were mixed at a molar ratio of 1:1.3. 5.32 g of lithium carbonate was added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 450°C at a heating rate of 8°C / min at room temperature and held for 4 h. Then, the temperature was increased to 875°C at a heating rate of 5°C / min and held for 15 h. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto a silver plate with a pre-cooling temperature of 120°C. Another silver plate was immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0039] Example 5 A method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the furnace to 700°C at a heating rate of 5°C / min and hold for 4 h to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide was mixed with lithium hydroxide / lithium chloride at a molar ratio of 1:1.2 (5:5). 2.79 g of lithium hydroxide and 2.82 g of lithium chloride were added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 400°C at a heating rate of 4°C / min at room temperature and held for 4 h. Then, the temperature was increased to 950°C at a heating rate of 8°C / min and held for 10 h. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto a copper plate with a pre-cooling temperature of 60°C. Another copper plate was immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0040] Example 6 A method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the mixture to 450°C at a heating rate of 6°C / min and hold it for 12 h to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide and lithium hydroxide were mixed at a molar ratio of 1:1.4. 6.51 g of lithium hydroxide was added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 500°C at a heating rate of 5°C / min at room temperature and held for 4 h. The temperature was then increased to 850°C at a heating rate of 5°C / min and held for 18 h. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto a copper plate with a pre-cooling temperature of 125°C. Another copper plate was then immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0041] Example 7 A method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the temperature to 600°C at a heating rate of 6°C / min and hold for 10 h to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide and lithium carbonate were mixed at a molar ratio of 1:1.4. 5.76 g of lithium carbonate was added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 450°C at a heating rate of 10°C / min at room temperature and held for 6 h. Then, the temperature was increased to 925°C at a heating rate of 2°C / min and held for 8 h. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto an aluminum plate with a pre-cooling temperature of 50°C. Another aluminum plate was immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0042] Example 8 A method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material includes the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the mixture to 350°C at a heating rate of 2°C / min and hold it for 15 h to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide and lithium carbonate were mixed at a molar ratio of 1:1.2. 4.91 g of lithium hydroxide was added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 475°C at a heating rate of 4°C / min at room temperature and held for 4 h. Then, the temperature was increased to 850°C at a heating rate of 5°C / min and held for 16 h. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto a copper plate with a pre-cooling temperature of 80°C. Another copper plate was immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0043] Comparative Example 1: Unquenched This comparative example demonstrates a method for preparing an all-solid-state lithium-rich manganese-based cathode material, including the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the temperature to 600°C at a heating rate of 5°C / min and hold for 6 h to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide and lithium hydroxide were mixed at a molar ratio of 1:1.35. 6.27 g of lithium hydroxide was added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 400℃ at a heating rate of 5℃ / min at room temperature and held for 5 h. Then, the temperature was increased to 950℃ at a heating rate of 2℃ / min and held for 15 h. After naturally cooling to room temperature, the powder product was collected to obtain the all-solid-state lithium-rich manganese-based cathode material.

[0044] Comparative Example 2 This comparative example demonstrates a method for preparing a cathode material, including the following specific steps: (1) Weigh 10 g of nickel manganese hydroxide precursor into a corundum crucible and place it in a muffle furnace with air introduced for sintering. Heat the temperature to 750°C at a heating rate of 5°C / min and hold for 6 hours to obtain pre-sintered nickel manganese hydroxide. (2) The pre-sintered nickel-manganese hydroxide and lithium hydroxide were mixed at a molar ratio of 1:1.35. 6.27 g of lithium hydroxide was added, and the mixture was stirred until homogeneous using a mixer. The mixture was then transferred to a high-temperature resistant corundum crucible with dimensions of 50*20*20 mm, leveled, cut into pieces, and then transferred to a muffle furnace with air circulation for sintering. The temperature was increased to 400°C at a heating rate of 5°C / min at room temperature and held for 5 h. Then, the temperature was increased to 950°C at a heating rate of 2°C / min and held for 15 h. After the holding period, the high-temperature powder was quickly removed from the furnace and poured onto a copper plate with a pre-cooling temperature of 80°C. Another copper plate was immediately placed on top, and the powder product was collected after it cooled naturally to room temperature. This yielded the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

[0045] Test case (1) Characterization of the structure and morphology of the cathode material.

[0046] The structure and morphology of the cathode materials prepared in the examples and comparative examples were characterized, and the results are as follows: Figure 1-2 , Figure 4-7 , Figure 9-14 As shown, the primary particles of the lithium-rich manganese-based cathode material in the examples exhibit a nanoplate-like morphology. These elongated nanoplates cross-link to form a three-dimensional interpenetrating structure, significantly increasing the specific surface area of ​​the material. During hot pressing, the edges of the laminations can penetrate the solid electrolyte matrix (such as sulfides / halides), establishing micro-region embedded physical contacts and reducing interfacial impedance. In contrast, the primary particles of the lithium-rich manganese-based cathode material in the comparative examples exhibit a spherical morphology, are more dense, and have fewer contact sites with the electrolyte after hot pressing.

[0047] (2) Electrochemical performance testing of cathode materials.

[0048] First-cycle charge-discharge performance: The prepared solid-state battery was placed in a constant-temperature blue battery test chamber at 45℃. The test program was set up, and the battery was first allowed to stand for 10 hours. Then, it was charged and discharged at a constant current at a rate of 0.05 C for one cycle of formation, with a voltage window of 1.4-4.2 V. After formation, the battery was run for another 100 cycles at a rate of 0.5 C. Finally, the test was completed.

[0049] The electrochemical performance of the cathode materials prepared in the examples and comparative examples was tested, and the results are as follows: Figure 3 , Figure 8 , Figure 15-16 As shown in Table 1, the discharge capacity of the nanoplate-shaped lithium-rich manganese-based cathode material in the examples is generally between 280 and 290 mAh / g, and the capacity retention rate after 100 cycles is over 87%. In contrast, the discharge capacity of the lithium-rich manganese-based cathode material in the comparative examples is between 260 and 265 mAh / g, and the capacity retention rate after 100 cycles is approximately 83%, significantly lower than that of the nanoplate-shaped lithium-rich manganese-based cathode material.

[0050] Table 1 Electrochemical performance of the examples and comparative examples In summary, the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material prepared by this invention has good consistency and stability, and has advantages such as high capacity, high initial efficiency, and good cycle performance in all-solid-state batteries. Moreover, the preparation method has the advantages of simple process, low cost, and high production efficiency.

[0051] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, characterized in that, Includes the following steps: (1) The nickel-manganese hydroxide precursor was sintered for the first time to obtain pre-sintered nickel-manganese hydroxide; (2) The pre-sintered nickel manganese hydroxide is mixed evenly with lithium salt, and then sintered a second time. The temperature is then raised to a third time to obtain high-temperature powder. The high-temperature powder is then quenched to obtain nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material.

2. The method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material according to claim 1, characterized in that, The chemical formula of the nickel-manganese hydroxide precursor in step (1) is Ni a Mn b (OH)2; where 0.2≤a≤0.45, 0.55≤b≤0.8, a+b=1.

3. The method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material according to claim 1, characterized in that, The conditions for the first sintering in step (1) are: heating to 300-700℃ at a heating rate of 2-10℃ / min and holding for 4-15 h.

4. The method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material according to claim 1, characterized in that, The lithium salt mentioned in step (2) includes at least one of lithium hydroxide, lithium carbonate, lithium chloride, and lithium nitrate.

5. The method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material according to any one of claims 1 to 4, characterized in that, The molar ratio of the pre-sintered nickel manganese hydroxide to the lithium salt in step (2) is 1:1.15~1.

55.

6. The method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material according to any one of claims 1 to 4, characterized in that, The conditions for the second sintering in step (2) are: heating to 400-600℃ at a heating rate of 2-10℃ / min and holding at that temperature for 2-10 h. The conditions for the third sintering in step (2) are: heating to 700-950℃ at a heating rate of 2-10℃ / min and then holding at that temperature for 8-18 hours.

7. The method for preparing a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material according to claim 1, characterized in that, The specific method for quenching the high-temperature powder is as follows: pour the high-temperature powder onto a metal plate or stone plate with a pre-cooling temperature of 30~150℃, then cover the high-temperature powder with another metal plate or stone plate of the same temperature, and allow it to cool naturally to room temperature.

8. A nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, characterized in that, The nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material is prepared by the preparation method described in any one of claims 1 to 7.

9. The nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material according to claim 8, characterized in that, The chemical formula of the nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material is Li. x Ni y Mn z O2; where 1.1≤x≤1.5, 0.2≤y≤0.5, 0.4≤z≤0.

8.

10. An application of a nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material, characterized in that, The nanoplate-shaped all-solid-state lithium-rich manganese-based cathode material according to any one of claims 8 to 9 is used in the preparation of all-solid-state lithium batteries.

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