Ternary positive electrode active material and all-solid-state battery

Abstract

The invention provides a ternary positive electrode active material and an all-solid-state battery. Wherein the ternary positive electrode active material has a layered structure, the ternary positive electrode active material comprises a matrix and a first coating layer located on at least part of the surface of the matrix, the matrix contains an N element, the first coating layer contains an N element, and the N content of the first coating layer is greater than that of the matrix; the chemical formula of the substrate is Li Ni < x > Co < y > M < z > G < k > O < f > N < g >, y < = 0.15, 0lt; z < = 0.15, 0 < = k < = 0.05, 0lt; g is less than or equal to 0.02, 1.8 lt; f is less than or equal to 2.1, a is more than or equal to 0.85 and less than or equal to 1.1, and M comprises at least one of Mn and Al; g comprises at least one of elements Mg, Al, Mn, Ti, Zr, Nb and Ta; m and G are different elements. The ternary positive electrode active material provided by the invention can improve the structural stability and rate capability of the all-solid-state battery.

Description

Technical Field

[0001] This invention relates to the field of battery materials, and more particularly to a ternary cathode active material and an all-solid-state battery. Background Technology

[0002] Solid-state batteries are widely used in new energy electric vehicles, large-scale energy storage systems, aerospace equipment, and high-end consumer electronics due to their high energy density, high safety, and long cycle life. Solid-state batteries can significantly improve driving range and eliminate the risk of thermal runaway; in energy storage systems, their high safety avoids environmental problems caused by liquid electrolyte leakage; in consumer electronics, their lightweight and high energy density characteristics meet the battery life requirements of portable devices. Furthermore, solid-state batteries can also be used in flexible electronic devices and micro-sensors, and the mechanical stability of their solid electrolytes makes them more adaptable to complex operating conditions.

[0003] High-nickel (Ni molar mass percentage of transition metals is 70% or higher) ternary layered oxides have become one of the preferred cathode materials for next-generation lithium-ion all-solid-state batteries due to their high specific capacity and relatively low cost. However, their commercial application still faces the following challenges: cation mixing during cycling (Ni... 2+ Occupy Li + The site exacerbates the structural degradation; the ionic / electron conductivity is insufficient at high magnification. Summary of the Invention

[0004] This invention provides a ternary cathode active material, which, on the one hand, can increase the interplanar spacing of the metal layer (such as the lithium layer) by nitrogen doping in the bulk matrix, thereby suppressing Ni²⁺. + Migration reduces cation mixing during cycling, improving the structural stability of the cathode active material; on the other hand, by doping nitrogen into the first coating layer, the electronic conductivity of the cathode active material is improved and oxygen release is suppressed, which can enhance the structural stability and rate performance of the ternary cathode active material.

[0005] The present invention also provides an all-solid-state battery, which, because it includes the above-mentioned ternary cathode active material, has good rate performance and cycle stability.

[0006] In a first aspect, the present invention provides a ternary cathode active material having a layered structure, comprising a matrix and a first coating layer located on at least a portion of the surface of the matrix, wherein the matrix contains nitrogen (N) and the first coating layer contains nitrogen (N), and the N content of the first coating layer is greater than the N content of the matrix; the chemical formula of the matrix is ​​Li. a Ni x Co y M z Gk O f N g where 0.7 ≤ x ≤ 0.95, 0 < y ≤ 0.15, 0 < z ≤ 0.15, 0 ≤ k ≤ 0.05, 0 < g ≤ 0.02, 1.8 < f ≤ 2.1, 0.85 ≤ a ≤ 1.1; M includes at least one of Mn and Al; G includes at least one of the elements Mg, Al, Mn, Ti, Zr, Nb, and Ta; M and G are different elements.

[0007] In an optional embodiment, the thickness of the first coating layer is 5 nm - 50 nm; preferably, the thickness of the first coating layer is 20 nm - 50 nm;

[0008] and / or; in the first coating layer, the mass content of N element is 3 wt% - 10 wt%;

[0009] and / or; the interplanar spacing of the (003) crystal plane of the matrix is 0.475 nm - 0.479 nm;

[0010] and / or; in the XRD of the ternary cathode active material, characteristic diffraction peaks exist in the range of 2θ = 18.5° - 18.6°.

[0011] In an optional embodiment, within the first coating layer, in the direction from the matrix to the first coating layer, the concentration gradient of the N element decreases.

[0012] [[ID=二十三]]In an optional embodiment, based on the total mass of the ternary cathode active material, the mass proportion of the N element is 0.1 wt% - 0.5 wt%.

[0013] In an optional embodiment, the first coating layer further contains C element, and the first coating layer sequentially includes a first carbon shell, a second carbon shell, and a third carbon shell in the direction away from the matrix; both the first carbon shell, the second carbon shell, and the third carbon shell include element C and element N;

[0014] where, taking the thickness of the first coating layer as 100%, in the direction from the matrix to the first coating layer, the first carbon shell is the region accounting for 0 - 25% of the thickness of the first coating layer, the third carbon shell is the region accounting for 0 - 25% of the thickness of the first coating layer in the direction from the surface of the first coating layer towards the matrix, and the remaining is the region of the second carbon shell;

[0015] [[ID=三十一]]The mass content of nitrogen element in the first carbon shell is not less than 40 wt%;

[0016] and / or, the mass content of nitrogen element in the second carbon shell is 1 wt% - 5 wt%;

[0017] And / or, the nitrogen content in the third carbon shell is 0.5wt%-2wt%.

[0018] In an alternative embodiment, the first carbon shell comprises pyrrole nitrogen, wherein the total nitrogen concentration in the pyrrole nitrogen is ≥40 wt% by mass, and / or, in the first carbon shell, the XPS binding energy of N1s is 399 eV-400.0 eV;

[0019] And / or, the second carbon shell comprises graphitic nitrogen;

[0020] And / or, the third carbon shell comprises nitrogen oxides, and / or, in the third carbon shell, the XPS binding energy of N1s is 403 eV-403.5 eV.

[0021] In an optional embodiment, the Dv50 of the ternary cathode active material is 1μm-10μm;

[0022] And / or, the specific surface area of ​​the ternary cathode active material is 0.9 m² / g-2.0 m² / g.

[0023] And / or, the compaction density of the ternary cathode active material is 3.4 g / cm³. 3 -4.2g / cm 3 .

[0024] In a second aspect, the present invention provides an all-solid-state battery, comprising a positive electrode, an electrolyte layer, and a negative electrode; the electrolyte layer is located between the positive electrode and the negative electrode, and the positive electrode comprises a ternary positive electrode active material as described in the first aspect.

[0025] In an alternative embodiment, the electrolyte layer comprises solid electrolyte particles: the solid electrolyte particles comprise a core and a shell covering at least a portion of the surface of the core; the core comprises a solid electrolyte matrix; the shell comprises a perfluorosulfonic acid polymer and a lithium salt.

[0026] In an optional embodiment, the molecular structure of the perfluorosulfonic acid polymer is: F(CF2)n-SO3H,O <n≤100。‌

[0027] Preferably, the solid electrolyte matrix comprises a cubic phase solid electrolyte;

[0028] Preferably, the cubic phase solid electrolyte includes at least one of silver sulfide germanium ore solid electrolyte, halide electrolyte, and oxide electrolyte;

[0029] Preferably, the lithium salt accounts for 1wt%-5wt% of the mass of the solid electrolyte particles.

[0030] Preferably, the average particle size of the solid electrolyte particles is 0.5 μm-5 μm;

[0031] Preferably, the thickness of the shell is 1nm-10nm;

[0032] Preferably, the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium fluorinated bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, and lithium hexafluorophosphate.

[0033] Preferably, the silver-sulfur germanium ore-based solid electrolyte includes Li 7-d+b R 1-b D b S 6-d-c T c X d Wherein, 1≤d≤1.5, 0≤b≤1, 0≤c≤1, X includes at least one of Cl, Br, and I; T includes at least one of O and Se; D is at least one of Si, Ge, and Sn; R includes at least one of P, As, and Sb.

[0034] The halide electrolyte includes LiAZ3, wherein A is at least one of Y, In, Sc, and Er; and Z includes at least one of Cl, Br, and I.

[0035] The oxide electrolyte includes Li 1+e E e B 2-e (PO4)3, Li7La3U2O 12 Li3OY, wherein E is at least one of Al, Ga, Cr, Sc, Y, and In, B includes at least one of Ti, Ge, Zr, and Hf, 0.1 ≤ e ≤ 0.8, U includes at least one of Zr, Nb, and Ta, and Y includes at least one of Cl and Br.

[0036] The positive electrode active material of the present invention, on the one hand, can increase the interplanar spacing of the metal layer (such as the lithium layer) by nitrogen doping in the bulk matrix, thereby suppressing Ni 2+ Migration reduces cation mixing during cycling, improving the structural stability of the cathode active material. On the other hand, by doping nitrogen into the first coating layer, the electronic conductivity of the cathode active material is improved and oxygen release is suppressed, which can further enhance the structural stability and rate performance, thereby helping to improve the stability and rate performance of the battery. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0038] Figure 1This is a schematic diagram of the structure of a ternary cathode active material according to a specific embodiment of the present invention;

[0039] In the diagram, 1-matrix, 2-first carbon shell, 3-second carbon shell, 4-third carbon shell;

[0040] Figure 2 This is the energy spectrum of all elements in the matrix of the ternary cathode active material of Example 1 of the present invention;

[0041] Figure 3 The energy spectrum of Ni element distribution in the matrix of the ternary cathode active material of Example 1 of the present invention;

[0042] Figure 4 This is the N element distribution energy spectrum of the matrix of the ternary positive electrode active material in Example 1 of the present invention;

[0043] Figure 5 This is a schematic diagram of the structure of the solid electrolyte particles in Experimental Example 1 of the present invention;

[0044] In the diagram, 5 represents the core, 6 represents the lithium salt, and 7 represents the casing.

[0045] Figure 6 This is a SEM image of the electrolyte layer in Experimental Example 1 of the present invention;

[0046] Figure 7 This is the energy spectrum of all elements in the electrolyte layer of Experimental Example 1 of the present invention;

[0047] Figure 8 The S element distribution energy spectrum of the electrolyte layer in Experimental Example 1 of this invention;

[0048] Figure 9 This is the N element distribution energy spectrum of the electrolyte layer in Experimental Example 1 of the present invention;

[0049] Figure 10 This is a schematic diagram of the all-solid-state battery structure in Application Example 2 of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In this application, the terms "first" and "second" are used only for descriptive purposes, to distinguish objects such as substances from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0052] In this application, references to "an embodiment," "an example," or "an example" mean that a specific feature, structure, or characteristic described in connection with that embodiment, example, or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination.

[0053] In existing technologies, the modification of high-nickel ternary cathode materials mainly includes the introduction of heterogeneous elements, surface coating, and microstructure regulation. Introducing heterogeneous elements (such as Al, Mg, Ti, etc.) to replace transition metals or oxygen sites can suppress cation mixing and structural degradation. However, the doping depth of heterogeneous elements is limited, making it difficult to effectively adjust lattice parameters, resulting in structural phase transitions during cycling. Surface coating suppresses side reactions between the high-nickel cathode and the electrolyte through oxide (such as La2O3), carbon materials, or polymer coating layers. However, while surface coating can improve electronic conductivity, traditional dry mixing methods easily lead to uneven coating and cannot solve the bulk stability problem. Microstructure regulation mainly involves designing single-crystal particles, core-shell structures, or composite microstructures to optimize ion / electron transport pathways. However, its synthesis process is complex and costly, and it does not fundamentally solve the oxygen release and ion diffusion kinetics problems of high-nickel materials.

[0054] To address the aforementioned problems, this invention proposes a differentiated functional distribution of nitrogen within the material (suppressing cation mixing and enhancing ion diffusion) and on the surface (enhancing electronic conductivity and suppressing oxygen release) through a synergistic design of bulk nitrogen doping and surface coating nitrogen doping. This results in a structural characteristic of "internal stability and external conductivity." Specifically, this invention provides the following technical solution:

[0055] In a first aspect, the present invention provides a ternary cathode active material having a layered structure. The ternary cathode active material includes a matrix and a first coating layer located on at least a portion of the surface of the matrix. The matrix contains nitrogen (N) element, the first coating layer contains nitrogen (N) element, and the N content of the first coating layer is greater than the N content of the matrix. The chemical formula of the matrix is ​​Li. a Ni x Co y Mz G k O f N g , where 0.7 ≤ x ≤ 0.95, 0 < y ≤ 0.15, 0 < z ≤ 0.15, 0 ≤ k ≤ 0.05, 0 < g ≤ 0.02, 1.8 < f ≤ 2.1, 0.85 ≤ a ≤ 1.1, M includes at least one of Mn and Al; G includes at least one of the elements Mg, Al, Mn, Ti, Zr, Nb and Ta; M and G are different elements.

[0056] In one embodiment, x + y + z + k = 1, f + g = 1;

[0057] The positive electrode active material of the present invention can synergistically improve the stability and rate performance of the positive electrode active material by introducing nitrogen into the matrix and regulating the N content of the first coating layer to be greater than the N content of the matrix. The main reasons include: the matrix is nitrogen-doped. At this time, nitrogen atoms replace the oxygen positions of the active material to form N-M bonds (M is the transition metal of the active material). Since the N-M bond energy > O-M bond, the stronger covalent bond firmly fixes the transition metal ions (such as Ni 2+ ) at their lattice sites, greatly hindering their migration to the lithium layer. This is the fundamental reason for suppressing the cation (such as Li + / Ni 2+ ) mixing. At the same time, since nitrogen atoms replace the oxygen positions of the active material, the (003) crystal plane spacing of the active material increases, and the stronger p-orbital hybridization of N atoms synergistically expands the metal ion layer spacing, promoting the diffusion of metal ions (such as Li + ). The N content of the first coating layer is greater than the N content of the matrix. Among them, the first coating layer is a high-nitrogen doping region, which can provide fast charge storage and pseudocapacitance effects, increase the carrier concentration of the first coating layer, establish a channel for the rapid transmission of ions and electrons in the matrix, and the high-nitrogen doping region also helps to further strengthen the crystal skeleton of the positive electrode active material, thereby further suppressing cation mixing and oxygen release; the matrix is a low-nitrogen doping region, which can ensure that when the first coating layer contacts the electrolyte, it still maintains an interface mainly composed of oxides and relatively "standard", avoiding unforeseen side reactions that may be caused by excessive N doping on the surface layer.

[0058] In some specific embodiments, the thickness of the first coating layer is 5 nm - 50 nm.

[0059] The first coating layer of the above thickness can form a uniform and dense protective layer on the substrate surface, effectively isolating the electrolyte from direct contact with the active material, thereby suppressing side reactions and the dissolution of transition metal ions, significantly improving the cycle stability and thermal safety of the ternary cathode active material. At the same time, this thickness also ensures that the N-containing coating layer maintains good ionic and electronic conductivity, promoting the rapid insertion and extraction of lithium ions, and further improving rate performance and capacity retention.

[0060] By way of example and not limitation, the thickness of the first covering layer can be tested using the following test methods:

[0061] The sample is prepared into ultrathin slices (less than 100 nm) using focused ion beam (FIB) technology, ensuring that the cross-section can be penetrated by the electron beam. Under high magnification (typically >500,000x) using HRTEM or scanning transmission electron microscopy (STEM), a clear, undisturbed particle edge is identified. Because the thickness of the first coating layer differs from the crystal structure of the matrix, it appears on the image as a continuous, uniform, and lighter-colored "halo" or "contrast layer" around the particle edge. The thickness of this contrast layer is directly measured on the image using a scale; this is the thickness of the first coating layer.

[0062] By way of example and not limitation, the thickness of the first coating layer is any value of 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, or any combination thereof.

[0063] In some specific embodiments, the thickness of the first coating layer is 20nm-50nm. This thickness of the first coating layer can form a more uniform and dense protective layer on the substrate surface, thereby more significantly suppressing side reactions and the dissolution of transition metal ions, improving the cycle stability and thermal safety of the ternary cathode active material, while ensuring that the coating layer maintains good ionic and electronic conductivity.

[0064] In some specific embodiments, the mass content of N element in the first coating layer is 3 wt%-10 wt%.

[0065] The appropriate nitrogen content mentioned above can further improve the intrinsic electronic conductivity of the first coating layer and reduce electrode polarization, which is key to improving the rate performance of the cathode. Secondly, the nitrogen content ensures that a sufficient number of nitrogen atoms provide lone pair electrons to form a certain degree of coordination bond (such as MNC) with transition metal ions on the substrate surface. This enhances the interfacial bonding between the coating layer and the substrate, making the first coating layer structure more robust during long-term cycling.

[0066] By way of example and not limitation, the first coating layer contains N element in any of the following mass values ​​or any combination of both: 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%.

[0067] In some embodiments, the interplanar spacing of the (003) crystal plane of the substrate is 0.475 nm to 0.479 nm.

[0068] By way of example and not limitation, the method for testing the interplanar spacing of the (003) crystal plane of the substrate includes the following procedures:

[0069] X-ray diffraction (XRD) was used for testing. A Cu-Kα radiation source (wavelength λ=0.15406nm) was used to perform fine step scans on the 2θ (18° to 20°) angles corresponding to the diffraction peaks of the (003) crystal plane in a low-speed continuous scanning mode to obtain high-resolution diffraction patterns. After obtaining the data, smoothing, background subtraction and precise fitting were performed to determine the peak position (2θ value). The spacing value of the (003) crystal plane was calculated according to the Bragg equation (nλ=2d sinθ).

[0070] In some embodiments, the XRD of the ternary cathode active material exhibits characteristic diffraction peaks in the range of 2θ between 18.5° and 18.6°.

[0071] In some specific embodiments, within the first coating layer, the concentration gradient of element N decreases in the direction from the substrate to the first coating layer.

[0072] The first coating layer in the above embodiment has a higher nitrogen content near the substrate, which ensures better lattice matching or chemical compatibility between the initial part of the first coating layer and the substrate crystal structure. It achieves initial stable adhesion through weaker chemical bonding (such as MOC), reducing interfacial stress caused by differences in thermal expansion coefficients, thereby improving the bonding strength and mechanical stability of the first coating layer. As the nitrogen content gradually decreases towards the surface, the overall electronic conductivity of the coating layer is gradually enhanced from the inside to the outside, forming an efficient electron transport channel. Moreover, the high concentration of nitrogen on the surface can greatly enhance the chemical inertness of the surface to the electrolyte and efficiently catalyze the decomposition of harmful substances such as HF, building a surface defense line. This gradient structure of "tough inside and strong outside" can effectively transfer current, suppress oxygen release and phase change in the layered structure during cycling, and minimize interfacial impedance and side reactions, thereby synergistically improving the cycle life and rate performance of the material.

[0073] By way of example and not limitation, the presence of nitrogen in the matrix and the gradient decrease in nitrogen concentration within the first coating layer can both be tested using the following methods:

[0074] First, XPS full-spectrum and N1s high-resolution spectral scanning were performed on the surface of the material to be tested, and a nitrogen signal was detected. Then, an argon ion gun was used to etch the same area of ​​the sample at the set energy and time, peeling off the coating layer layer by layer. After each etching period, XPS scanning was performed on the newly exposed surface again. Throughout the process, the signal changes of the elements were monitored synchronously. Since the nitrogen doping amount of the first coating layer decreased along the direction away from the substrate, a weak but repeatable N1s signal was detected. The binding energy position of this signal was consistent with that of lattice nitrogen (in the range of 398.5 eV to 398.7 eV), thus concluding that there is an N1s characteristic peak in the substrate.

[0075] In some implementations, the mass percentage of nitrogen element is 0.1wt%-0.5wt% based on the total mass of the ternary cathode active material.

[0076] The above-mentioned ternary cathode active materials with nitrogen content are sufficient to effectively utilize the functions of nitrogen in improving interfacial conductivity, enhancing coating adhesion, and stabilizing surface chemistry. At the same time, they avoid the unnecessary interfacial defects caused by excessive nitrogen content penetrating into the bulk phase or forming an electrochemically inert phase, which would damage the integrity of the main crystal lattice structure.

[0077] For example, the N element has a mass percentage of 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, or any combination thereof, based on the total mass of the ternary cathode active material.

[0078] In some embodiments, the first coating layer comprises N and C elements, and the first coating layer is located in a direction away from the substrate 1, see [reference needed]. Figure 1 It includes a first carbon shell 1, a second carbon shell 2, and a third carbon shell 3 in sequence; the first carbon shell, the second carbon shell, and the third carbon shell all include elements C and N; wherein, taking the thickness of the first coating layer as 100%, along the direction from the substrate to the first coating layer, the first carbon shell is a region accounting for 0~25% of the thickness of the first coating layer, the third carbon shell is a region accounting for 0~25% of the thickness of the first coating layer along the direction from the surface of the first coating layer to the substrate, and the remainder is the region of the second carbon shell;

[0079] The nitrogen content in the first carbon shell is not less than 40 wt%; the nitrogen content in the coating layer decreases gradually from the first carbon shell to the third carbon shell.

[0080] Among the ternary cathode active materials, the first carbon shell has the highest nitrogen (N) content, while the matrix has the lowest. This allows for almost no increase in ion diffusion resistance, while simultaneously forming the strongest Ni-NC coordination bonds with Ni ions on the cathode material surface through the lone pair electrons of nitrogen, firmly anchoring the first coating layer to the matrix and ensuring its integrity and long-term effectiveness. The second carbon shell, within the aforementioned thickness range, forms a continuous and dense carbon layer, effectively bridging the inner and outer layers and establishing a good electronic conductivity path. Simultaneously, the second carbon shell within this thickness range also possesses good mechanical strength to buffer stress between the inner and outer layers, suppressing volume expansion and particle breakage of the cathode active material during cycling. The third carbon shell, within the aforementioned region, ensures, on the one hand, that a sufficient amount of nitrogen oxide functional groups (-NO2, -ONO) exist on the outermost surface, enabling continuous and effective formation of a stable interface with the sulfide electrolyte, providing long-term protection for the internal active material; on the other hand, the thickness of the third coating layer provides a more ample depth of chemical protection, especially under high voltage or long-cycle conditions.

[0081] The method for measuring the thickness of the first, second, and third carbon shells relative to the first coating layer includes the following steps: The sample is prepared into an ultrathin slice (less than 100 nm) using focused ion beam (FIB) technology, ensuring the cross-section can be penetrated by the electron beam. A clear, undisturbed particle edge is identified under high magnification (typically >500,000x) using HRTEM or scanning transmission electron microscopy (STEM). Due to the different crystal structures of the first, second, and third carbon shells relative to the matrix, they appear on the image as three continuous, uniform, and lighter-colored "halos" or "contrast layers" outside the particle edge. The thickness of each contrast layer is directly measured on the image using a scale.

[0082] In some specific implementations, 100 particles are randomly selected, and 50 locations are randomly selected from each particle for measurement. The average value is then taken to obtain the thickness of the first carbon shell, the second carbon shell, and the third carbon shell.

[0083] In the above-described embodiment, since the nitrogen content of the first carbon shell is not less than 40 wt%, a strong internal conductive network can be established for the entire positive electrode active material. Electrons can pass through the first carbon shell almost unimpeded and be rapidly transported to the electrochemically active regions of the second and third carbon shells, thereby providing rapid charge storage for the positive electrode active material. Furthermore, because the first carbon shell is in contact with the substrate, the nitrogen in the first carbon shell interacts strongly with the transition metal atoms on the core surface, which can further stabilize the metal-oxygen bonds at the interface, thereby further increasing the stability of the positive electrode active material.

[0084] For example, the mass content of nitrogen in the first carbon shell is any value or a range of any two of the following: 40wt%, 42wt%, 44wt%, 45wt%, 47wt%, 49wt%, 50wt%, 51wt%, 53wt%, 55wt%, 57wt%, 60wt%, 65wt%.

[0085] In some embodiments, the nitrogen content in the second carbon shell is 1wt%-5wt%.

[0086] The second carbon shell is located between the first and third carbon shells and is an intermediate transition layer. When its nitrogen content is within the above range, it can quickly conduct metal ions that have penetrated from the outside to the inside and can also quickly export electrons from the inside. This avoids a huge kinetic barrier between the first and third carbon shells and effectively buffers the stress caused by volume changes during cycling, thereby indirectly suppressing cation mixing and oxygen release caused by mechanical failure.

[0087] For example, the mass content of nitrogen in the second carbon shell is any value or a range of any two of the following: 1wt%, 2wt%, 2.2wt%, 2.5wt%, 2.7wt%, 2.9wt%, 3.0wt%, 3.2wt%, 3.5wt%, 4wt%, 5wt%.

[0088] In some embodiments, the nitrogen content in the third carbon shell is 0.5wt%-2wt%.

[0089] The third carbon shell is the outermost layer of the positive electrode active material. When its nitrogen content is within the aforementioned range, it ensures that the surface of the third carbon shell has moderate lithiophilicity. This provides an optimal energy barrier for the migration of lithium ions at the positive electrode-electrolyte interface, which is the final and most crucial step in enhancing ion diffusion. Furthermore, the nitrogen doping concentration within the aforementioned range ensures that its low reactivity prevents it from becoming a catalyst for electrolyte oxidation, thereby suppressing the chain reaction initiated by interfacial oxygen release and further increasing the stability of the positive electrode active material.

[0090] For example, the mass content of nitrogen in the third carbon shell is any value or a range of any two of the following: 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, 1.5wt%, 2.0wt%.

[0091] In some embodiments, the mass content of nitrogen in different carbon layers of the first coating can be tested by the following methods:

[0092] Scanning test: First, XPS full spectrum and N1s high-resolution scans are performed on the original surface of the material to be tested. At this time, the sum of nitrogen signals of the first coating layer is measured. Then, fine argon ion sputtering is performed. A low-energy, short-time argon ion beam is used to perform controlled slight etching to expose the surface of the first coating layer without completely etching it through. The exposed new surface is then scanned with high-resolution N1s.

[0093] Data Analysis: a. Total Nitrogen Content: The atomic percentage of nitrogen (N) was directly read from the relative atomic concentration (at.%) of each element measured by XPS. This value represents the total nitrogen doping amount of the first coating layer. b. Peak fitting was performed on the obtained N1s spectrum to decompose the area of ​​the total nitrogen peak into the first, second, and third sub-peaks. The mass content (%) of nitrogen in the first carbon shell was calculated as follows: (Area of ​​the first sub-peak / Total area of ​​the N1s peak) × 100%; the mass content (%) of nitrogen in the second carbon shell was calculated as follows: (Area of ​​the second sub-peak / Total area of ​​the N1s peak) × 100%; the mass content (%) of nitrogen in the third carbon shell was calculated as follows: (Area of ​​the third sub-peak / Total area of ​​the N1s peak) × 100%.

[0094] In some embodiments, the first carbon shell comprises pyrrole nitrogen, wherein the total nitrogen concentration in the pyrrole nitrogen is ≥40 wt%.

[0095] And / or, in the first carbon shell, the XPS binding energy of N1s is 399 eV-400.0 eV.

[0096] Among them, pyrrole nitrogen can form MNC coordination bonds with carbon atoms on the pyrrole ring and transition metal M on the surface of the active material, which tightly binds the first coating layer to the matrix, preventing the first coating layer from falling off or cracking due to internal stress, and ensuring the integrity and long-term effectiveness of the first coating layer. The lone pair electrons of pyrrole nitrogen are directly injected into the empty d orbitals of the transition metal through coordination bonds, which establishes a natural electron channel with extremely low resistance between the carbon shell and the active material, providing rapid charge storage and pseudocapacitive effect for the positive electrode active material.

[0097] In some embodiments, the second carbon shell comprises graphitic nitrogen.

[0098] The second carbon shell, serving as a transition layer, needs to possess good mechanical strength to buffer the stress between the inner and outer layers. Graphite nitrogen strengthens the sp of the carbon layer. 2 The conjugated network enhances the modulus and toughness of the second carbon shell, helping to maintain the structural integrity of the positive electrode active material during long-term cycling.

[0099] In some embodiments, the third carbon shell comprises nitrogen oxides, and / or, in the third carbon shell, the XPS binding energy of N1s is 403 eV-403.5 eV.

[0100] In sulfide all-solid systems, the third carbon shell, including nitrogen oxides, can also reduce the interfacial impedance of the sulfide electrolyte membrane.

[0101] In some embodiments, the Dv50 of the ternary cathode active material is 1μm-3μm. Cathode active materials within this range ensure that the compaction density of the cathode sheet is within a suitable range, thereby guaranteeing the energy density of the battery.

[0102] The Dv50 of the aforementioned ternary cathode active material refers to the particle size value corresponding to 50% (by volume) of the cumulative amount in the particle size distribution curve. It can be regarded as the median particle size of the material and is generally obtained by laser diffraction particle size distribution instrument.

[0103] For example, the Dv50 of the ternary cathode active material is any value or a range of any combination of 1μm, 1.5μm, 2μm, 2.5μm, 3μm, etc.

[0104] In some embodiments, the specific surface area of ​​the ternary cathode active material is 0.9 m² / g to 2.0 m² / g. Cathode active materials with such specific surface areas have more active sites, which can further improve the intercalation efficiency of metal ions.

[0105] For example, the specific surface area of ​​the ternary cathode active material is 0.9 m². 2 / g, 1.0m 2 / g, 1.2m 2 / g, 1.5m 2 / g, 1.7m 2 / g, 1.9m 2 / g, 2.0m 2 Any value in / g, or a range consisting of any two of them.

[0106] In some embodiments, the compaction density of the ternary cathode active material is 3.4 g / cm³. 3 -4.2g / cm 3 .

[0107] The ternary cathode active material with the above compaction density has a closer contact between particles, which can better transform the physical contact between particles into an electrochemically stable and lower resistance conductive path. Thus, while achieving high density, it avoids the increase in electrode polarization and the decrease in rate performance caused by the increase in contact resistance.

[0108] For example, the compaction density of the ternary cathode active material is 3.4 g / cm³. 3 3.5g / cm 3 3.7g / cm 3 3.9g / cm 3 4.0g / cm 34.2g / cm 3 The range of any value in the range, or any combination of both.

[0109] An exemplary, and not limiting, method for preparing a ternary cathode active material includes the following steps:

[0110] The matrix raw material is heat-treated at 300℃-350℃ in an atmosphere containing ammonia to obtain the matrix;

[0111] In a mixed system including pyrrole and oxidant, a matrix is ​​added, and a polymerization reaction is carried out at 4℃-6℃ to obtain the first intermediate;

[0112] In a nitrogen atmosphere, the first intermediate is kept at 300℃-350℃ for 1-5 hours to obtain the second intermediate;

[0113] In an atmosphere containing reducing gas, the second intermediate is heated to 500℃-600℃ and held for 1-5 hours to obtain the third intermediate;

[0114] In an oxygen-containing atmosphere, the third intermediate is kept at 650℃-700℃ for 1-3 hours to obtain a ternary cathode active material.

[0115] The above preparation method involves low-temperature nitriding of the matrix raw material in ammonia to replace oxygen sites with nitrogen atoms, forming a matrix. Under the action of an oxidant, pyrrole is polymerized in the matrix to form an amorphous polypyrrole layer. Subsequently, through step-carbonization, the pre-carbonized polypyrrole layer at 300℃-350℃ undergoes dehydrogenation to form a conjugated polycyclic structure (reaction formula: (C4H5N)n→ (C4H2N)n+3H2↑), retaining pyrrole nitrogen. Reduction at 500℃-600℃ promotes the transformation of the five-membered ring into a six-membered sp² carbon ring to generate graphitic nitrogen. Finally, at 650℃-700℃, the surface carbon is selectively oxidized by trace amounts of oxygen to form nitrogen oxides containing C=O and NO bonds, while removing non-carbon impurities.

[0116] For example, the base material is subjected to heat preservation treatment at any value or any combination of two of 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, etc.

[0117] For example, the matrix undergoes a polymerization reaction at any value of 4°C, 5°C, 6°C, or any combination thereof.

[0118] For example, the first intermediate is subjected to heat preservation treatment for 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, etc., at any value or any combination of two of the following: 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, etc.

[0119] For example, the second intermediate is heated to any value of 500°C, 550°C, 570°C, 600°C, or any combination thereof, and then kept at that temperature for a period of 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or any combination thereof.

[0120] For example, the third intermediate is heated to any value of 650°C, 670°C, 690°C, 700°C, or any combination thereof, and then kept at that temperature for 1 hour, 2 hours, 3 hours, or any combination thereof.

[0121] In some specific embodiments, the oxidizing agents include, but are not limited to, ferric chloride hexahydrate (FeCl3·6H2O), ammonium persulfate ((NH4)2S2O8), anhydrous copper chloride (CuCl2), hydrogen peroxide (H2O2), etc.

[0122] To further ensure the polymerization of pyrrole on the matrix surface, in some specific embodiments, the molar ratio of pyrrole to oxidant is 1:0.2-0.5. More specifically, it is 1:0.2, 1:0.3, 1:0.4, 1:0.5, etc.

[0123] In some specific embodiments, the atmosphere containing ammonia is a mixture of ammonia and argon, wherein the volume percentage of ammonia is 10%-20%. Exemplarily, the volume percentage of ammonia is any value or a range of any combination of 10%, 12%, 15%, 17%, 20%, etc.

[0124] In some specific embodiments, the atmosphere containing reducing gas is a mixture of hydrogen and argon, wherein the volume percentage of hydrogen is 3%-10%. Exemplarily, the volume percentage of hydrogen is any value or a range of any combination of 3%, 5%, 7%, 9%, 10%, etc.

[0125] In some specific embodiments, the oxygen-containing atmosphere is a mixture of oxygen and argon, wherein the volume percentage of oxygen is 0.01%-0.07%. For example, the volume percentage of oxygen is any value or a range of any two of the following: 0.01%, 0.02%, 0.04%, 0.05%, 0.07%.

[0126] In some specific embodiments, the active material is heated to 300℃-350℃ at a heating rate of 1℃ / min-10℃ / min; the first intermediate is heated to 300℃-350℃ at a heating rate of 1℃ / min-10℃ / min; the second intermediate is heated to 500℃-600℃ at a heating rate of 1℃ / min-10℃ / min; and the third intermediate is heated to 650℃-700℃ at a heating rate of 1℃ / min-10℃ / min.

[0127] It is understood that the positive electrode sheet including the above ternary positive electrode active material is also within the scope of protection of this invention. The positive electrode sheet includes a current collector and a material layer disposed on one side of the current collector. The material layer includes the ternary positive electrode active material of the first aspect.

[0128] When the positive electrode is used in a solid-state battery, in one specific embodiment, the material layer further includes a solid electrolyte; wherein the solid electrolyte includes one or a mixture of oxide solid electrolytes, sulfide solid electrolytes, polymer solid electrolytes and halide solid electrolytes.

[0129] In a second aspect, the present invention provides an all-solid-state battery, comprising a positive electrode, an electrolyte layer, and a negative electrode; the electrolyte layer is located between the positive electrode and the negative electrode, and the positive electrode comprises the ternary positive electrode active material of the first aspect.

[0130] Among them, see Figure 5 The electrolyte layer includes solid electrolyte particles: the solid electrolyte particles include: a core 5, and a shell 7 covering at least part of the surface of the core; the core includes a solid electrolyte matrix; the shell includes a perfluorosulfonic acid polymer (PFSA) and a lithium salt 6.

[0131] The aforementioned electrolyte layer, through the three-dimensional synergy of a solid electrolyte matrix, perfluorosulfonic acid polymer, and lithium salt, can construct an electrolyte layer system characterized by "high ionic conductivity, low interfacial impedance, and resistance to side reactions." This electrolyte layer, along with the nitrogen gradient distribution of the ternary cathode material, can synergistically address the structural degradation and rate performance issues of high-nickel ternary batteries, thereby improving the overall performance of all-solid-state batteries. Specifically, the sulfonic acid groups of the perfluorosulfonic acid polymer possess strong acidity, enabling it to achieve >90% lithium-ionization (-SO3H → -SO3) even in a solid-state environment. - Li + The delocalized negative charge is distributed through S=O bonds, forming a low-barrier lithium-ion transport pathway. Furthermore, the planar triangular configuration (bond angle 120°) of the sulfonic acid groups in the perfluorosulfonic acid polymer allows a single group to simultaneously form three hydrogen bonds—two through oxygen atom acceptors and one through a hydrogen atom donor. This multi-bonding capability enables it to bond with the S=O bonds on the surface of the solid electrolyte. - / Li +The formation of a high-density cross-linked network further reduces the interfacial energy barrier and improves the lithium-ion diffusion coefficient. The hydrophobicity and chemical inertness of the perfluoroalkane chain (-CF2-CF2-) in the perfluorosulfonic acid polymer ensures the stability of the sulfonic acid groups below 200°C. The strong electronegativity of the fluorine atoms enhances the polarity of the sulfonic acid groups through an inductive effect, lowering the lithium-ion solvation energy and thus increasing the ion migration rate. Simultaneously, nitrogen doping in the first coating layer of the ternary cathode active material improves the electronic conductivity of the cathode. The combined effect of these two factors improves the rate performance of solid-state batteries. After formation, the sulfonic acid groups in the perfluorosulfonic acid polymer are partially reduced to -SO2. - It can react with lithium salts to form lithium sulfonate (-SO3Li). The chemical stability of the -SO2- group is better than that of -SO3H, making it less likely to decompose with lithium metal or electrolyte. Furthermore, -SO3Li itself is a lithium source and can act as a "relay station" for lithium-ion transport. When slight interface loss occurs, it can act as a buffer to provide a small amount of lithium ions to replenish the lithium. At the same time, since nitrogen doping can expand the interplanar spacing of the metal layer (such as the lithium layer) in the matrix of the ternary cathode active material, reducing cation mixing during cycling, the electrolyte layer and the ternary cathode material can simultaneously enhance the stability of the solid-state battery.

[0132] In some embodiments, the perfluorosulfonic acid polymer is designated as Aquivion® D72-25BS.

[0133] In some embodiments, the solid electrolyte matrix includes a cubic phase solid electrolyte. The cubic phase solid electrolyte ensures that the electrolyte layer possesses extremely high intrinsic and ionic conductivity.

[0134] In some embodiments, the cubic solid electrolyte includes at least one of silver sulfide germanium ore solid electrolyte, halide electrolyte, and oxide electrolyte.

[0135] Among them, the Li⁺-rich and high defect activity of the surface chemical state of silver sulfide germanium ore-based solid electrolytes are prerequisites for achieving hydrogen bond interface modification of perfluorosulfonic acid polymers, while their mechanical and thermal stability provides underlying support for the safety and process compatibility of the electrolyte layer. Halide electrolytes can be directly paired with cathode materials such as high-nickel and high-voltage lithium cobalt oxide, thus balancing high conductivity and stability at high-voltage cathodes; oxide electrolytes have a wide electrochemical window, high stability at the positive and negative electrode interfaces, and are less prone to side reactions leading to electrolyte decomposition, thus ensuring safety.

[0136] In some embodiments, the silver-sulfur germanium ore-based solid electrolyte includes Li 7-d+b R 1-b D b S 6-d-c T c X dWherein, 1≤d≤1.5, 0≤b≤1, 0≤c≤1, X includes at least one of Cl, Br, and I; T includes at least one of O and Se; D includes at least one of Si, Ge, and Sn; R includes at least one of P, As, and Sb; the halide electrolyte includes LiAZ3, where A includes at least one of Y, In, Sc, and Er; Z includes at least one of Cl, Br, and I; and the oxide electrolyte includes Li 1+e E e B 2-e (PO4)3, Li7La3U2O 12 Li3OY, wherein E includes at least one of Al, Ga, Cr, Sc, Y, and In; B includes at least one of Ti, Ge, Zr, and Hf, 0.1 ≤ e ≤ 0.8; U includes at least one of Zr, Nb, and Ta; and Y includes at least one of Cl and Br.

[0137] In some implementations, the lithium salt accounts for 1 wt% to 5 wt% of the mass of the solid electrolyte particles.

[0138] In this process, adding an appropriate amount of lithium salt can dissolve or form a local high-concentration lithium ion source at the grain boundaries between solid electrolyte particles. These free lithium ions can fill the inherent defects and vacancies at the grain boundaries, providing a "stepping stone" for the transition of lithium ions between particles.

[0139] For example, the mass percentage of lithium salt is any value or a range of any two of the following: 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%.

[0140] In some implementations, the thickness of the housing is 3nm-5nm.

[0141] Among them, the sulfonic acid group (-SO3H) of PFSA has extremely strong acidity (pKa≈-3), and can efficiently replace protons with Li⁺ even in a solid environment, forming a dynamic, Li⁺-rich interface layer. The shell of the above thickness is precisely Li⁺. + The ideal distance for rapid proton conduction via the "Grotthuss mechanism," namely the efficient transition of Li⁺ between adjacent sulfonic acid groups, enables the shell to build an ultrafast ion transport bridge between solid electrolyte particles and electrode particles (especially the positive electrode), greatly reducing the contact resistance of the solid-solid interface.

[0142] For example, the thickness of the shell is any value or a range of any two of the following: 3nm, 3.5nm, 4nm, 4.5nm, 5nm, etc.

[0143] In some embodiments, the average particle size of the solid electrolyte particles is 2 μm-3 μm.

[0144] For example, the average particle size of the solid electrolyte particles is any value or a range of any two of the following: 2 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3.0 μm.

[0145] The average particle size of solid electrolyte particles can be measured using a scanning electron microscope (SEM): Use SEM to obtain a surface morphology image of the solid electrolyte particles, take at least 100 test points in the image, measure the size of the solid electrolyte particles in each test point, and calculate the average value.

[0146] In some embodiments, the lithium salt includes at least one of lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium fluorinated bis(trifluoromethanesulfonyl)imide (LiFTFSI), lithium tetrafluoroborate (LiBF4), and lithium hexafluorophosphate (LiPF6).

[0147] The lithium salts mentioned above are preferentially reduced during charging and discharging, forming a LiF-rich SEI film on the negative electrode surface, which suppresses interfacial side reactions. Furthermore, the F- in the lithium salts is affinity-reactive to the perfluorinated skeleton of the perfluorosulfonic acid polymer, forming a "sulfide-PFSA-lithium salt" gradient interfacial layer, which can synergistically reduce the lithium-ion diffusion barrier of the electrolyte layer.

[0148] In some embodiments, the thickness of the electrolyte layer is 10 μm to 50 μm.

[0149] For example, the thickness of the electrolyte layer is any value or a range of any two of the following: 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm.

[0150] In some embodiments, the electrolyte layer is prepared by a method comprising the following processes:

[0151] A mixture containing a solid electrolyte matrix, a perfluorosulfonic acid polymer, a lithium salt, and a dispersant is ball-milled to obtain a slurry. The slurry is then formed into a film, dried, and kept at 110-130℃ for 1-3 hours to obtain an electrolyte layer.

[0152] When the solid electrolyte matrix is ​​an acerobenzene ore-based solid electrolyte, the above method can simultaneously trigger -SO3H and S by holding at 110-130℃ for 1-3 hours. - / Li + Hydrogen bonding reduces interfacial impedance drop and prevents the decomposition of perfluorosulfonic acid polymers caused by high-temperature sintering.

[0153] In some embodiments, ball milling is performed using zirconia balls (3 mm) at 600 rpm for 2 hours to uniformly disperse the solid electrolyte matrix, perfluorosulfonic acid polymer, and lithium salt, resulting in a slurry with appropriate viscosity.

[0154] In some embodiments, the slurry is formed into a film by casting, for example, by coating a polyimide substrate with a fluorosilane release agent and using a doctor blade to cast the slurry into a film.

[0155] In some implementations, drying is performed in stages (50°C, 4h → 60°C, 6h → 80°C, 2h → 120°C, 1h) to ensure complete solvent evaporation.

[0156] Perfluorosulfonic acid polymers not only have ion conduction capabilities but also provide mechanical adhesion. Therefore, there is no need to add traditional binders (such as nitrile rubber) to the raw materials of the electrolyte layer.

[0157] The present invention does not specifically limit the composition and material of the negative electrode sheet of the battery. Exemplarily, in some embodiments, the battery further includes a negative electrode sheet, which comprises a current collector and a negative electrode material layer located on at least one surface of the current collector. The negative electrode material layer comprises a negative electrode active material, a conductive agent, a solid electrolyte, a binder, and a dispersant. The negative electrode active material may be selected from one or more of graphite, hard carbon, soft carbon, silicon-based negative electrode, titanium-based material, nitride, tin compound, and lithium metal. The conductive agent may be selected from at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotubes, metal powder, and graphene. The binder may be selected from... The electrolyte may be selected from at least one of the following: carboxymethyl cellulose, styrene-butadiene rubber, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyvinyl alcohol, and sodium polyacrylate; the dispersant may be selected from at least one of the following: sodium carboxymethyl cellulose, triethylhexyl phosphate, and sodium dodecyl sulfate; the negative electrode current collector may be a conventional negative electrode current collector in the art, such as copper foil; the solid electrolyte may include one or a mixture of more than one of the following: oxide solid electrolyte, sulfide solid electrolyte, polymer solid electrolyte, and halide solid electrolyte.

[0158] In some embodiments, the fabrication steps of a solid-state battery include the following steps:

[0159] 1. The positive electrode, electrolyte layer, and negative electrode are arranged in an orderly manner to obtain the electrode core.

[0160] 2. Core casing.

[0161] 3. Isostatic pressing treatment of the casing and pole core.

[0162] 4. Cell formation.

[0163] To further understand the present invention, the technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0164] Unless otherwise specified, all reagents involved in the embodiments of this invention are commercially available products and can be purchased through commercial channels.

[0165] The perfluorosulfonic acid polymer used in the following tests is Aquivion. ® D72-25BS.

[0166] Example 1

[0167] A solid-state battery includes a positive electrode, an electrolyte layer, and a negative electrode; the electrolyte layer is located between the positive electrode and the negative electrode.

[0168] The fabrication of solid-state batteries includes the following steps:

[0169] (1) A method for preparing ternary cathode active materials, comprising the following steps:

[0170] 1. Take high-nickel ternary powder LiNi 0.8 Co 0.1 Mn 0.1 100g of O2 (Dv50=2.5μm, BET=1.8m² / g) was placed in a corundum crucible and vacuum dried at 250℃ for 2h in a tube furnace to remove adsorbed water. Then, a low-temperature ammonia nitriding process was used. Under the atmosphere of NH3 / Ar mixed gas (NH3 volume percentage 10%), the gas flow rate was 200sccm, the temperature was increased to 300℃ at 5℃ / min and held for 2h. After cooling to room temperature, the matrix can be obtained.

[0171] 2. Add 10 mL of pyrrole (99.9% purity) and 4.82 g of oxidizing agent FeCl3·6H2O (molar ratio of pyrrole:FeCl3). 3+ =1:0.3) was added to 200 mL of anhydrous acetonitrile solvent, and the mixture was magnetically stirred at 500 rpm for 30 min until the solution turned brownish-red. Then, the matrix was added and the mixture was placed in a low-temperature reactor (5±1℃) for low-temperature polymerization and coating. The mixture was stirred at 200 rpm for 6 h, centrifuged, and washed three times with ethanol. A 5 nm amorphous polypyrrole layer could be generated on the surface of the matrix to obtain the first intermediate.

[0172] 3. First, the first intermediate is pre-carbonized. Under a N2 atmosphere, the temperature is increased to 330℃ at 5℃ / min and held for 3 hours. The polypyrrole layer is dehydrogenated to form a conjugated polycyclic structure, resulting in the second intermediate. Then, under an Ar / H2 mixed atmosphere of 95:5, the temperature is increased to 570℃ and held for 2 hours. Hydrogen participates in the reduction reaction, promoting the transformation of the five-membered ring into a six-membered sp² carbon ring to generate graphite nitrogen, resulting in the third intermediate. Finally, the temperature is raised to 650℃ and held for 2 hours in an Ar / O2 mixed atmosphere of 99.95:0.05 to form nitrogen oxide, thus obtaining the ternary cathode active material.

[0173] The ternary cathode active material was tested and found to have a Dv50 of 2 μm and a BET of 1.1 m² / g. The ternary cathode active material comprises a substrate and a first coating layer disposed on at least a portion of the substrate surface. The first coating layer comprises nitrogen-doped carbon material. Along the direction away from the substrate, the first coating layer includes a first carbon shell: pyrrole nitrogen, a second carbon shell: graphitic nitrogen, and a third carbon shell: nitrogen oxide, with the nitrogen doping amount decreasing progressively (see Table 1). The interplanar spacing of the (003) crystal plane of the substrate is 0.475 nm–0.479 nm. The XRD pattern of the ternary cathode active material exhibits characteristic diffraction peaks in the range of 2θ between 18.5° and 18.6°. The substrate satisfies the following condition: in the X-ray photoelectron spectroscopy, it includes an N1s characteristic peak with an elution position of 398.5 eV–398.7 eV. Figure 2 The energy spectrum of all elements in the matrix of the ternary cathode active material; Figure 3 The energy spectrum of Ni element distribution in the matrix; Figure 4 The image shows the N element distribution energy spectrum of the matrix, which indicates that the elemental distribution in the matrix prepared in this example is uniform.

[0174] (2) Prepare a positive electrode sheet using the above-mentioned positive electrode active material:

[0175] 1. The positive electrode active material, sulfide electrolyte (Li6PS5Cl), conductive agent (VGCF), and binder (PVDF) are uniformly mixed in a mass ratio of 83%:15%:1%:1%, with a solid-liquid mass ratio of 1:2. The mixture is then dispersed in anhydrous p-xylene and ultrasonically dispersed for 2 hours. After ultrasonication, the mixture is stirred thoroughly at 350 rpm for 6-8 hours to obtain the positive electrode slurry.

[0176] 2. The positive electrode slurry is uniformly coated onto the current collector aluminum foil. The thickness of the positive electrode sheet is 150 μm, and the surface load is 30 mg / cm². 2 After vacuum drying at 60℃ for 12 hours, and then rolling, a compacted density of 4.0 g / cm³ can be obtained. 3 The positive electrode sheet should be prepared in a dry room or glove box throughout the entire positive electrode sheet preparation process to avoid contact with water molecules in the air.

[0177] (3) Preparation of electrolyte layer

[0178] Its preparation method includes the following steps:

[0179] 1. The precursors Li2S, P2S5, and LiCl were mixed in a molar ratio of 2:2:1.5. Zirconia balls (5 mm in diameter, ball-to-material ratio 30:1) were added to a ball mill jar in an argon glove box (H2O < 0.1 ppm, O2 < 0.1 ppm). The mixture was ball-milled at 400 rpm for 6 h and then sintered in an argon atmosphere at 550 °C for 10 h to obtain the sulfide electrolyte Li6PS5Cl. The powder sample with Dv50 = 2-10 μm was obtained by sieving.

[0180] 2. Li6PS5Cl powder sample and PFSA dispersion (solid content 25%) were mixed and stirred with a planetary stirrer at 200 rpm for 30 min until preliminary dispersion was achieved. LiFSI and ethyl propionate (ethyl propionate volume percentage 30% based on the total mass of the mixture) were added. Zirconia ball milling beads with a diameter of 3 mm and a ball-to-particle ratio of 20:1 were used. After ball milling at 600 rpm for 2 h, a slurry was obtained. At 25 °C, its viscosity was 350 ± 50 mPa·s and its shear rate was 100 s⁻¹. -1 ;

[0181] 3. Casting and Drying the Slurry: A release agent (fluorosilane) is coated onto the surface of a polyimide (PI) substrate (100 μm thick). The doctor blade gap is 300 μm (corresponding to a dry film thickness of 30 μm), and the feed rate is 0.5 m / min. The coated electrolyte membrane is dried in stages: 50℃ for 4 h to initially evaporate the solvent, 60℃ for 6 h to suppress surface wrinkles, 80℃ for 2 h to completely evaporate the solvent, and 120℃ for 1 h to trigger the reaction of SO3H with S. - / Li + Hydrogen bonds are formed to obtain the electrolyte layer.

[0182] in, Figure 6 This is a SEM image of the electrolyte layer in this example; Figure 7 This is the energy spectrum of all elements in the electrolyte layer in this example; Figure 8 This is the energy spectrum of the S element distribution in the electrolyte layer in this example; Figure 9 The image shows the N element distribution energy spectrum of the electrolyte layer in this example; it can be seen that the elemental distribution in the electrolyte layer prepared in this example is uniform.

[0183] (4) Preparation of negative electrode sheet

[0184] 1. Remove the oxide layer and impurities from the surface of the high-purity lithium ingot in a drying room to expose a fresh, metallic-lustered surface. Wrap it on both sides with PET release film and place it in an adjustable-gap roller press for repeated thinning and pressing until the lithium block is stretched into a uniform sheet of the required thickness, 50μm.

[0185] 2. A 6μm thick copper foil is acid-washed (e.g., with dilute hydrochloric acid), cleaned with deionized water, cleaned with ethanol, and vacuum-dried to remove surface oxides and contaminants. The PET release film covering one side of the lithium sheet is peeled off, and the freshly exposed lithium side is quickly and smoothly adhered to the prepared clean copper foil. A roll press (usually at a lower pressure than when rolling lithium) is used to roll the copper foil side, ensuring tight contact between the lithium layer and the copper foil, eliminating air bubbles, and obtaining the negative electrode sheet.

[0186] (5) All-solid-state battery assembly

[0187] 1. The positive electrode sheet and the electrolyte layer are pressed by hot pressing process, and a continuous and dense electrolyte-positive electrode interface can be formed by holding it at 100℃ and 50MPa pressure for 5 minutes;

[0188] 2. The negative electrode sheet is then pressed under the same hot-pressing conditions, sealed in an aluminum-plastic bag, and vacuum-sealed to obtain an all-solid-state battery. Figure 10 This is a schematic diagram of the solid-state battery.

[0189] Example 2

[0190] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. Specific differences are shown in Table 1. The only difference in the preparation method compared to Example 1 is that, in preparing the ternary cathode active material, step 1 involves taking high-nickel ternary powder LiNi... 0.8 Co 0.1 Mn 0.1 100g of O2 (Dv50=2.5μm, BET=1.8m² / g) was placed in a corundum crucible and vacuum dried at 250℃ for 2h in a tube furnace to remove adsorbed water. Then, a low-temperature ammonia nitriding process was adopted. Under the atmosphere of NH3 / Ar mixed gas (NH3 volume percentage 10%), the gas flow rate was 200sccm, the temperature was increased to 300℃ at 5℃ / min and held for 4h. After cooling to room temperature, the matrix can be obtained.

[0191] Example 3

[0192] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. Specific differences are shown in Table 1. The only difference in the preparation method compared to Example 1 is that, in preparing the ternary cathode active material, step 1 involves taking high-nickel ternary powder LiNi... 0.8 Co 0.1 Mn 0.1100g of O2 (Dv50=2.5μm, BET=1.8m² / g) was placed in a corundum crucible and vacuum dried at 250℃ for 2h in a tube furnace to remove adsorbed water. Then, a low-temperature ammonia nitriding process was adopted. Under the atmosphere of NH3 / Ar mixed gas (NH3 volume percentage 10%), the gas flow rate was 200sccm, the temperature was increased to 300℃ at 5℃ / min and held for 0.5h. After cooling to room temperature, the matrix can be obtained.

[0193] Example 4

[0194] The difference between this and the all-solid-state battery of Example 1 lies in the change of parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference in the preparation method compared to Example 1 is that in the preparation of the ternary cathode active material, step 3 is as follows: First, the first intermediate is pre-carbonized and heated to 300°C at 5°C / min under N2 atmosphere and held for 3 hours. The polypyrrole layer is dehydrogenated to form a conjugated polycyclic structure, resulting in the second intermediate. Then, the temperature is raised to 570°C and held for 2 hours under a mixed atmosphere of Ar / H2=95:5. Hydrogen participates in the reduction reaction, promoting the transformation of the five-membered ring into a six-membered sp² carbon ring to generate graphite nitrogen, resulting in the third intermediate. Finally, the temperature is raised to 650°C and held for 2 hours under a mixed atmosphere of Ar / O2=99.95:0.05 to form nitrogen oxide, thus obtaining the ternary cathode active material.

[0195] Example 5

[0196] The difference between this and the all-solid-state battery of Example 1 lies in the change of parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference in the preparation method compared to Example 1 is that, in the preparation of the ternary cathode active material, step 3 is as follows: First, the first intermediate is pre-carbonized and heated to 350°C at 5°C / min under N2 atmosphere and held for 3 hours. The polypyrrole layer is dehydrogenated to form a conjugated polycyclic structure, resulting in the second intermediate. Then, the temperature is raised to 570°C and held for 2 hours under a mixed atmosphere of Ar / H2=95:5. Hydrogen participates in the reduction reaction, promoting the transformation of the five-membered ring into a six-membered sp² carbon ring to generate graphite nitrogen, resulting in the third intermediate. Finally, the temperature is raised to 650°C and held for 2 hours under a mixed atmosphere of Ar / O2=99.95:0.05 to form nitrogen oxide, thus obtaining the ternary cathode active material.

[0197] Examples 6-8

[0198] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. For specific differences, please refer to Table 1. The only difference between this and Example 1 is that when preparing the ternary cathode active material, the heat preservation time of the first intermediate in step 3 of Examples 6-8 is changed to 1h, 5h, and 10h, respectively.

[0199] Examples 9-12

[0200] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference between this and Example 1 is that in the preparation of the ternary cathode active material, step 3 is as follows: the temperature is raised to 480°C and held for 2 hours in an Ar / H2 = 95:5 mixed atmosphere. Hydrogen participates in the reduction reaction, which promotes the transformation of the five-membered ring into a six-membered sp² carbon ring to generate graphite nitrogen, thus obtaining the third intermediate. Finally, the temperature is raised to 650°C (the temperature in Example 10 is 550°C, the temperature in Example 11 is 600°C, and the temperature in Example 12 is 630°C), and held for 2 hours in an Ar / O2 = 99.95:0.05 mixed atmosphere to form nitrogen oxide, thus obtaining the ternary cathode active material.

[0201] Examples 13-15

[0202] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference between this and Example 1 is that in the preparation of the ternary cathode active material, step 3: heating to 570°C and holding at that temperature in an Ar / H2 = 95:5 mixed atmosphere. The holding times in Examples 13-15 were 0.5h, 1h, 6h, and 8h, respectively, to obtain the third intermediate. Finally, the temperature was raised to 650°C and held at that temperature for 2h in an Ar / O2 = 99.95:0.05 mixed atmosphere to form nitrogen oxides and obtain the ternary cathode active material.

[0203] Examples 16-18

[0204] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference in the preparation method compared to Example 1 is that, in the preparation of the ternary cathode active material, step 3 is as follows: First, the first intermediate is pre-carbonized and heated to 330°C at 5°C / min under N2 atmosphere and held for 3 hours to obtain the second intermediate. Then, the temperature is raised to 570°C and held for 2 hours under Ar / H2=95:5 mixed atmosphere to obtain the third intermediate. Finally, the temperature is raised to 650°C (wherein, the temperatures in Examples 17 and 18 are raised to 720°C and 750°C respectively), and held for 2 hours under Ar / O2=99.95:0.05 mixed atmosphere to form nitrogen oxides, thus obtaining the ternary cathode active material.

[0205] Example 19

[0206] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference between this and Example 1 is that in preparing the ternary cathode active material, step 3 is as follows: First, the first intermediate is pre-carbonized and heated to 330°C at 5°C / min under N2 atmosphere and held for 3 hours to obtain the second intermediate. Then, the temperature is raised to 570°C and held for 2 hours under Ar / H2=95:5 mixed atmosphere to obtain the third intermediate. Finally, the temperature is raised to 650°C and held for 0.5 hours under Ar / O2=99.95:0.05 mixed atmosphere to form nitrogen oxides and obtain the ternary cathode active material.

[0207] Example 20

[0208] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference between this and Example 1 is that in preparing the ternary cathode active material, step 3 is as follows: First, the first intermediate is pre-carbonized and heated to 330°C at 5°C / min under N2 atmosphere and held for 3 hours to obtain the second intermediate. Then, the temperature is raised to 570°C and held for 2 hours under Ar / H2=95:5 mixed atmosphere to obtain the third intermediate. Finally, the temperature is raised to 650°C and held for 2.5 hours under Ar / O2=99.95:0.05 mixed atmosphere to form nitrogen oxides and obtain the ternary cathode active material.

[0209] Example 21

[0210] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference between this and Example 1 is that in preparing the ternary cathode active material, step 3 is as follows: First, the first intermediate is pre-carbonized and heated to 330°C at 5°C / min under N2 atmosphere and held for 3 hours to obtain the second intermediate. Then, the temperature is raised to 570°C and held for 2 hours under Ar / H2=95:5 mixed atmosphere to obtain the third intermediate. Finally, the temperature is raised to 650°C and held for 3 hours under Ar / O2=99.95:0.05 mixed atmosphere to form nitrogen oxides and obtain the ternary cathode active material.

[0211] Example 22

[0212] The difference between this and the all-solid-state battery of Example 1 lies in the change of the parameters of the ternary cathode active material. The specific differences are shown in Table 1. The only difference between this and Example 1 is that in preparing the ternary cathode active material, step 3 is as follows: First, the first intermediate is pre-carbonized and heated to 330°C at 5°C / min under N2 atmosphere and held for 3 hours to obtain the second intermediate. Then, the temperature is raised to 570°C and held for 2 hours under Ar / H2=95:5 mixed atmosphere to obtain the third intermediate. Finally, the temperature is raised to 650°C and held for 5 hours under Ar / O2=99.95:0.05 mixed atmosphere to form nitrogen oxides and obtain the ternary cathode active material.

[0213] Examples 23-38

[0214] The difference between this and the all-solid-state battery of Example 1 lies in the change of electrolyte layer parameters, as detailed in Table 2. The only difference in the preparation method compared to Example 1 is that, during electrolyte layer preparation, the thickness of the electrolyte layer is adjusted by changing the size of the solid electrolyte particles and the shell, or by changing the scraper gap.

[0215] Comparative Example 1

[0216] The difference between this and the all-solid-state battery of Example 1 is that the N element content of the ternary cathode active material is a fixed value. For specific differences, please refer to Table 1. The only difference between this and Example 1 is that the substrate obtained in step 1 is directly used as the ternary cathode active material.

[0217] Test case

[0218] Electrolyte layer performance testing

[0219] 1. Interfacial Impedance: Equipment: Solartron 1260, frequency 0.1Hz-1MHz, amplitude 5-10mV. A sulfide electrolyte membrane, 10 mm in diameter, was sandwiched within a stainless steel blocking electrode and prepared under a pressure of 350 MPa. The test pressure was also 350 MPa. σ = A / Rd, where σ is the ionic conductivity (S / cm), R is the interfacial impedance (Ω), d is the electrolyte membrane thickness (cm), and A is the electrode area (cm²). The raw data obtained from the test are the impedance values ​​at different frequencies, usually represented by a Nyquist plot. By fitting the plot using an equivalent circuit model, the specific value of the interfacial impedance can be quantified. In the equivalent circuit, the interfacial process is often represented by a circuit unit with a resistor (R) and a capacitor (C) in parallel. The value of this resistor R is the interfacial impedance or charge transfer impedance. It directly reflects the ease with which ions cross the interface.

[0220] 2. Lithium-ion transference number (t) li +The Bruce-Vincent polarization method derives the lithium-ion transference number by applying a constant current to an electrolyte and measuring the change in polarization voltage over different times. Specifically, a symmetrical battery structure (e.g., Li|electrolyte|Li) is used. A constant current of 3A is applied to the electrolyte, and the voltage change over time is recorded. The lithium-ion transference number is calculated based on the slope of the polarization curve and the steady-state voltage. The lithium-ion transference number (tLi) is... + ) is defined as: t Li + =D Li + &c Li + / D total &c total Where D Li + This is the diffusion coefficient of lithium ions, in m. 2 / S;c Li + This represents the concentration of lithium ions, in mol / m³. 3 ;D total The diffusion coefficient of total ions, in m. 2 / S;c total This represents the total ion concentration, in mol / m³. 3 .

[0221] 3. Critical Current Density: Equipment: Solartron 1260, using a symmetrical cell structure (e.g., Li|electrolyte|Li), at 25°C, from 1 mA cm⁻¹ -2 The process involves constant current charging (deposition) → resting → constant current discharging (dissolution) → resting, with each "deposition + dissolution" cycle lasting 30 minutes to 1 hour. 2-5 cycles are performed at each current density to observe voltage stability. After each stable current density cycle, the voltage is adjusted at a fixed step size of 0.1 mA cm⁻¹. -2 Increasing the current density will cause lithium dendrites to form and pierce the electrolyte membrane when it reaches a certain critical value, leading to an internal short circuit in the battery. The maximum current density before this short circuit occurs is called the critical current density, measured in mA / cm². -2 .

[0222] Battery performance test

[0223] 1. Capacity retention test: The all-solid-state secondary battery is charged to 4.3V at a rate of 0.1C, then kept at constant voltage for 5 minutes, and then discharged to 2.5V at a rate of 0.3C, which constitutes one cycle. The discharge capacity of the first cycle is C1, and the discharge capacity after 200 cycles is C2. The capacity retention rate = C2 / C1 × 100%;

[0224] 2. Rate Performance Test: At 25°C, the battery is charged at a constant current density of 0.1C to 4.3V, then charged at a constant voltage of 4.3V with a cutoff current of 0.05C. After resting for 10 minutes, it is discharged at a current density of 0.1C to 2.5V, and then rested for 10 minutes. This charge-discharge process is repeated three times, and the discharge capacity of the battery in these three cycles is recorded as the discharge capacity at 0.1C. Similarly, after the battery reaches 4.3V after the same charging process, it is discharged at current densities of 1C, 2C, and 3C to 2.5V, and three discharges are performed at each different rate. The average value is taken as the discharge capacity at that rate. The rate retention rate is calculated as: (Specific rate discharge capacity / 0.1C rate discharge capacity) × 100%.

[0225] The results are shown in Table 2.

[0226] Table 1

[0227]

[0228] Table 2

[0229]

[0230] As can be seen from Tables 1 and 2, compared with Comparative Example 1, the positive electrode active materials of Examples 1-22 improved the stability and rate performance of the all-solid-state battery by setting a gradient nitrogen distribution in the substrate and the first coating layer; while Examples 23-38 can further improve the cycle performance and rate performance of the all-solid-state battery by adjusting the parameters of the electrolyte layer.

[0231] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ternary cathode active material, characterized in that, The ternary cathode active material has a layered structure. The ternary cathode active material includes a matrix and a first coating layer located on at least a part of the surface of the matrix. The matrix contains N element, the first coating layer contains N element, and the N content of the first coating layer is greater than the N content of the matrix; the chemical formula of the matrix is Li a Ni x Co y M z G k O f N g , where 0.7 ≤ x ≤ 0.95, 0 < y ≤ 0.15, 0 < z ≤ 0.15, 0 ≤ k ≤ 0.05, 0 < g ≤ 0.02, 1.8 < f ≤ 2.1, 0.85 ≤ a ≤ 1.1, M includes at least one of Mn and Al; G includes at least one of the elements Mg, Al, Mn, Ti, Zr, Nb and Ta; M and G are different elements.

2. The ternary cathode active material according to claim 1, characterized in that, The thickness of the first coating layer is 5nm-50nm; preferably, the thickness of the first coating layer is 20nm-50nm. And / or; the mass content of N element in the first coating layer is 3 wt%-10 wt%; And / or; the interplanar spacing of the (003) crystal plane of the substrate is 0.475 nm-0.479 nm; And / or; the XRD of the ternary cathode active material has characteristic diffraction peaks in the range of 2θ of 18.5°-18.6°.

3. The ternary cathode active material according to claim 1 or 2, characterized in that, Within the first coating layer, the concentration gradient of element N decreases in the direction from the substrate to the first coating layer.

4. The ternary cathode active material according to any one of claims 1-3, characterized in that, Based on the total mass of the ternary cathode active material, the mass percentage of nitrogen element is 0.1wt%-0.5wt%.

5. The ternary cathode active material according to any one of claims 1-4, characterized in that, The first coating layer further comprises element C. The first coating layer, along the direction away from the substrate, sequentially includes a first carbon shell, a second carbon shell, and a third carbon shell. The first carbon shell, the second carbon shell, and the third carbon shell all comprise elements C and N. Assuming the thickness of the first coating layer is 100%, along the direction from the substrate to the first coating layer, the first carbon shell occupies a region of 0-25% of the thickness of the first coating layer, the third carbon shell occupies a region of 0-25% of the thickness of the first coating layer along the direction from the surface of the first coating layer towards the substrate, and the remainder is the region of the second carbon shell. The nitrogen content in the first carbon shell is not less than 40 wt%; And / or, the nitrogen content in the second carbon shell is 1wt%-5wt% by mass; And / or, the nitrogen content in the third carbon shell is 0.5wt%-2wt%.

6. The ternary cathode active material according to claim 5, characterized in that, The first carbon shell comprises pyrrole nitrogen, with a total nitrogen concentration of ≥40 wt% by mass, and / or, in the first carbon shell, the XPS binding energy of N1s is 399 eV-400.0 eV; And / or, the second carbon shell comprises graphitic nitrogen; And / or, the third carbon shell comprises nitrogen oxides, and / or, in the third carbon shell, the XPS binding energy of N1s is 403 eV-403.5 eV.

7. The ternary cathode active material according to any one of claims 1-6, characterized in that, The Dv50 of the ternary cathode active material is 1μm-10μm; And / or, the specific surface area of ​​the ternary cathode active material is 0.9 m². 2 / g-2.0m 2 / g; And / or, the compaction density of the ternary cathode active material is 3.4 g / cm³. 3 -4.2g / cm 3 .

8. An all-solid-state battery, characterized in that, It includes a positive electrode, an electrolyte layer, and a negative electrode; the electrolyte layer is located between the positive electrode and the negative electrode, and the positive electrode includes the ternary positive electrode active material according to any one of claims 1-8.

9. The all-solid-state battery according to claim 8, characterized in that, The electrolyte layer comprises solid electrolyte particles: the solid electrolyte particles comprise a core and a shell covering at least a portion of the surface of the core; the core comprises a solid electrolyte matrix; the shell comprises a perfluorosulfonic acid polymer and a lithium salt.

10. The all-solid-state battery according to claim 9, characterized in that, The solid electrolyte matrix includes a cubic phase solid electrolyte; Preferably, the cubic phase solid electrolyte includes at least one of silver sulfide germanium ore solid electrolyte, halide electrolyte, and oxide electrolyte; Preferably, the lithium salt accounts for 1wt%-5wt% of the mass of the solid electrolyte particles. Preferably, the average particle size of the solid electrolyte particles is 0.5 μm-5 μm; Preferably, the thickness of the shell is 1nm-10nm; Preferably, the lithium salt comprises at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium fluorinated bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, and lithium hexafluorophosphate; Preferably, the thickness of the electrolyte layer is 10 μm-60 μm; Preferably, the silver-sulfur germanium ore-based solid electrolyte includes Li 7-d+b R 1-b D b S 6-d-c T c X d Wherein, 1≤d≤1.5, 0≤b≤1, 0≤c≤1, X includes at least one of Cl, Br, and I; T includes at least one of O and Se; D is at least one of Si, Ge, and Sn; R includes at least one of P, As, and Sb. The halide electrolyte comprises LiAZ3, wherein A comprises at least one of Y, In, Sc, and Er; and Z comprises at least one of Cl, Br, and I. The oxide electrolyte includes Li 1+e E e B 2-e (PO4)3, Li7La3U2O 12 Li3OY, wherein E includes at least one of Al, Ga, Cr, Sc, Y, and In; B includes at least one of Ti, Ge, Zr, and Hf; 0.1 ≤ e ≤ 0.8; U includes at least one of Zr, Nb, and Ta; and Y includes at least one of Cl and Br.

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