Preparation method of high-rate lithium-rich manganese-based composite cathode material

Abstract

The application discloses a preparation method of a high-rate lithium-rich manganese-based composite positive electrode material, which comprises the following steps: preparing a lithium-rich manganese-based inner core, constructing an interface regulation layer, and constructing a lithium ion storage station. The application breaks through the conventional method by constructing an interface regulation layer-lithium ion storage station composite structure outside the lithium-rich manganese-based material. The interface regulation layer has a continuous electron-ion transmission network, which actively reduces the charge transfer resistance of the interface. In addition, the lithium ion storage station forms a concentration gradient driving force to pull the inner core to be delithiated during discharging, and avoids lithium deposition during charging. As a result, the interface regulation layer and the lithium ion storage station form a complementary and synergistic system, which solves three core problems, i.e., slow bulk phase kinetics, blocked interface transmission, and lattice reconstruction. Meanwhile, the system is suitable for a solid-state battery system, improves the solid-solid interface compatibility, realizes the synergistic regulation of lithium ion storage buffering and rapid transmission, significantly improves the rate performance of the material, and improves the cycle stability.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, and in particular to a method for preparing a high-rate lithium-rich manganese-based composite cathode material. Background Technology

[0002] Lithium-rich manganese-based cathode materials are considered one of the core cathode materials for next-generation high-energy-density lithium-ion batteries due to their advantages such as high specific capacity (above 250 mAh / g), high safety, and low cost, and have broad application prospects in electric vehicles, large-scale energy storage, and other fields. However, existing lithium-rich manganese-based cathode materials have significant shortcomings in rate performance, which severely limits their application in high-power demand scenarios.

[0003] Lithium-rich manganese-based cathode materials face significant rate performance bottlenecks in practical applications, with the core issues stemming from three aspects: First, the low lithium-ion diffusion coefficient and electronic conductivity within the bulk material result in a natural lag in the kinetics of ion-electron transport. Second, during charge-discharge cycles, especially in the delithiation stage, the material's crystal structure is prone to irreversible reconstruction, further compressing lithium-ion diffusion channels and exacerbating kinetic inertia. Third, in solid-state battery systems, the solid-solid interface between the lithium-rich manganese-based cathode and the solid electrolyte presents significant transport barriers, greatly hindering the interfacial cross-domain migration of lithium ions, thus further amplifying the rate performance shortcomings.

[0004] Current research on the modification of lithium-rich manganese-based cathode materials largely focuses on performance optimization in a single dimension. For example, while expanding lithium-ion diffusion channels through bulk heterogeneous ion doping can improve bulk transport efficiency to some extent, it fails to overcome the core challenge of interfacial transport obstruction. Surface coating strategies, although capable of creating physical barriers to reduce side reactions between the material and the electrolyte, generally suffer from a single-function limitation—traditional coatings often lack efficient ion transport capabilities, and may even increase lithium-ion transport resistance due to excessive coating thickness, resulting in limited capacity retention improvement at high rates. Taking common oxide coatings such as TiO2 and LiNbO3 as examples, their core function is only to improve cycle stability, with minimal impact on rate performance. While solid electrolyte-based coatings can reduce interfacial impedance, they do not achieve active regulation of lithium-ion transport, failing to match the inherent kinetic characteristics of lithium-rich manganese-based cathodes.

[0005] Therefore, it is necessary to propose a new solution to improve the above problems so that high rate performance and excellent cycle performance can be obtained at the same time. Summary of the Invention

[0006] In view of this, the present invention addresses the deficiencies of the existing technology, and its main objective is to provide a method for preparing high-rate lithium-rich manganese-based composite cathode materials. This method can effectively solve the problem that the modification of existing lithium-rich manganese-based cathode materials can only significantly improve one performance and cannot simultaneously obtain high rate and excellent cycle performance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a high-rate lithium-rich manganese-based composite cathode material includes the following steps: (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 20-40 min to obtain a first mixed solution. An inert gas was bubbled into the first mixed solution for 10-30 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 4-6 h, followed by calcination at 800-1200 °C for 12-16 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.1-0.2g of graphene, 0.05-0.1g of carbon nanotubes, and 0.0075-0.015g of LiNO3 were added. After ultrasonic dispersion for 30-60min, the mixture was stirred and dried at 40-60℃ for 5-7h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) +Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.2-0.5 g of LATP powder, 0.3-0.8 g of PEO and 0.01-0.05 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s, and then vacuum dried at 100-120 °C for 9-15 h to obtain a lithium-rich manganese-based composite cathode material with LATP / PEO composite storage station coated on its surface.

[0008] As a preferred embodiment, in step (1), the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%.

[0009] As a preferred embodiment, in step (2), the Li + The thickness of the doped graphene / carbon nanotube layer is 10-30 nm.

[0010] As a preferred embodiment, in step (3), the thickness of the LATP / PEO composite storage station is 60 nm.

[0011] As a preferred embodiment, in step (1), the inert gas is nitrogen.

[0012] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution: This invention innovatively employs a composite structure of "interface regulation layer - lithium-ion storage station" constructed on the outer side of lithium-rich manganese-based materials. The interface regulation layer has a continuous electron-ion transport network, actively reducing the charge transfer resistance at the interface. Combined with the lithium-ion storage station, which forms a concentration gradient driving force during discharge to induce core delithiation and avoids lithium deposition during charging, the interface regulation layer and the lithium-ion storage station form a functionally complementary synergistic system. This solves the three core problems of slow bulk dynamics, impeded interface transport, and lattice reconstruction. At the same time, it is compatible with solid-state battery systems, improves solid-solid interface compatibility, and achieves synergistic regulation of lithium-ion storage buffering and rapid transport, significantly improving the rate performance of the material and improving cycle stability.

[0013] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to specific embodiments. Detailed Implementation

[0014] This invention discloses a method for preparing a high-rate lithium-rich manganese-based composite cathode material, which includes the following steps: It includes the following steps: (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 20-40 min to obtain a first mixed solution. An inert gas was bubbled into the first mixed solution for 10-30 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 4-6 h, followed by calcination at 800-1200 °C for 12-16 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0015] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.1-0.2g of graphene, 0.05-0.1g of carbon nanotubes, and 0.0075-0.015g of LiNO3 were added. After ultrasonic dispersion for 30-60min, the mixture was stirred and dried at 40-60℃ for 5-7h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 10-30 nm.

[0016] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.2-0.5 g of LATP powder, 0.3-0.8 g of PEO and 0.01-0.05 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s, and then vacuum dried at 100-120 °C for 9-15 h to obtain a lithium-rich manganese-based composite cathode material with an LATP / PEO composite storage station coated on its surface. The thickness of the LATP / PEO composite storage station was 60 nm.

[0017] The following detailed description is provided in conjunction with several embodiments and comparative examples.

[0018] Example 1 (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 30 min to obtain the first mixed solution. An inert gas was bubbled into the first mixed solution for 20 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 5 h, followed by calcination at 800-1200 °C for 14 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0019] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.1g of graphene, 0.05g of carbon nanotubes, and 0.0075g of LiNO3 were added. After ultrasonic dispersion for 45min, the mixture was stirred and dried at 60℃ for 6h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 10 nm.

[0020] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.2 g of LATP powder, 0.3 g of PEO and 0.01 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s, and then vacuum dried at 110 °C for 11 h to obtain a lithium-rich manganese-based composite cathode material with an LATP / PEO composite storage station on its surface. The thickness of the LATP / PEO composite storage station was 60 nm.

[0021] Example 2 (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 30 min to obtain the first mixed solution. An inert gas was bubbled into the first mixed solution for 20 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 5 h, followed by calcination at 800-1200 °C for 14 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0022] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.2g of graphene, 0.1g of carbon nanotubes, and 0.015g of LiNO3 were added. After ultrasonic dispersion for 45min, the mixture was stirred and dried at 60℃ for 6h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 30 nm.

[0023] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.2 g of LATP powder, 0.3 g of PEO and 0.01 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s, and then vacuum dried at 110 °C for 11 h to obtain a lithium-rich manganese-based composite cathode material with an LATP / PEO composite storage station on its surface. The thickness of the LATP / PEO composite storage station was 60 nm.

[0024] Example 3 (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 20 min to obtain a first mixed solution. An inert gas was bubbled into the first mixed solution for 30 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 4 h, followed by calcination at 800 °C for 16 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0025] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.13g of graphene, 0.08g of carbon nanotubes, and 0.009g of LiNO3 were added. After ultrasonic dispersion for 60min, the mixture was stirred and dried at 40℃ for 6h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 25 nm.

[0026] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.3 g of LATP powder, 0.5 g of PEO and 0.05 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s and then vacuum dried at 100 °C for 9 h to obtain a lithium-rich manganese-based composite cathode material with LATP / PEO composite storage station coated on its surface.

[0027] Example 4 (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 40 min to obtain the first mixed solution. An inert gas was bubbled into the first mixed solution for 10 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 6 h, followed by calcination at 800 °C for 16 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0028] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.16g of graphene, 0.07g of carbon nanotubes, and 0.01g of LiNO3 were added. After ultrasonic dispersion for 40min, the mixture was stirred and dried at 55℃ for 6h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 20 nm.

[0029] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.5 g of LATP powder, 0.8 g of PEO and 0.04 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s and then vacuum dried at 120 °C for 15 h to obtain a lithium-rich manganese-based composite cathode material with LATP / PEO composite storage station coated on its surface.

[0030] Example 5 (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 30 min to obtain the first mixed solution. An inert gas was bubbled into the first mixed solution for 25 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 5 h, followed by calcination at 800-1200 °C for 15 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0031] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.12g of graphene, 0.06g of carbon nanotubes, and 0.0095g of LiNO3 were added. After ultrasonic dispersion for 50min, the mixture was stirred and dried at 60℃ for 7h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 10-30 nm.

[0032] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.4 g of LATP powder, 0.8 g of PEO and 0.04 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s and then vacuum dried at 115 °C for 10 h to obtain a lithium-rich manganese-based composite cathode material with LATP / PEO composite storage station coated on its surface.

[0033] Example 6 (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 30 min to obtain the first mixed solution. An inert gas was bubbled into the first mixed solution for 20 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 5 h, followed by calcination at 800-1200 °C for 14 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0034] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.2g of graphene, 0.1g of carbon nanotubes, and 0.015g of LiNO3 were added. After ultrasonic dispersion for 45min, the mixture was stirred and dried at 60℃ for 6h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 30 nm.

[0035] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.3 g of LATP powder, 0.3 g of PEO and 0.03 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s and then vacuum dried at 100-120 °C for 9-15 h to obtain a lithium-rich manganese-based composite cathode material with LATP / PEO composite storage station coated on its surface.

[0036] Comparative Example 1 (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 30 min to obtain the first mixed solution. An inert gas was bubbled into the first mixed solution for 20 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 5 h, followed by calcination at 800-1200 °C for 14 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0037] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.1g of graphene, 0.05g of carbon nanotubes, and 0.0075g of LiNO3 were added. After ultrasonic dispersion for 45min, the mixture was stirred and dried at 60℃ for 6h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 10 nm.

[0038] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.2 g of LATP powder, 1.8 g of PEO and 0.01 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s and then vacuum dried at 110 °C for 11 h to obtain a lithium-rich manganese-based composite cathode material with LATP / PEO composite storage station coated on its surface.

[0039] Comparative Example 2 (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 30 min to obtain the first mixed solution. An inert gas was bubbled into the first mixed solution for 20 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 5 h, followed by calcination at 800-1200 °C for 14 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0040] (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.1g of graphene, 0.05g of carbon nanotubes, and 0.0075g of LiNO3 were added. After ultrasonic dispersion for 45min, the mixture was stirred and dried at 60℃ for 6h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; the Li + The thickness of the doped graphene / carbon nanotube layer is 10 nm.

[0041] (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.2 g of LATP powder and 0.3 g of PEO were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s and then vacuum dried at 110 °C for 11 h to obtain a lithium-rich manganese-based composite cathode material with LATP / PEO composite storage station coated on its surface.

[0042] Comparative Example 3 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 30 min to obtain the first mixed solution. An inert gas was bubbled into the first mixed solution for 20 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain the polymer precursor. The polymer precursor was then kept at 500 °C for 5 h, followed by calcination at 800-1200 °C for 14 h to obtain a lithium-rich manganese-based cathode material with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%, and the inert gas is nitrogen.

[0043] Performance tests were conducted on the above embodiments, and the test results are shown in Table 1. The test methods are as follows: A positive electrode sheet was prepared by mixing positive electrode material, conductive carbon black, and polyvinylidene fluoride in a mass ratio of 8:1:1; a conventional solid-state button cell was assembled using lithium sheet as negative electrode and LATP as solid electrolyte.

[0044]

[0045] Table 1 Analyzing the above data and comparing Example 1 with Comparative Example 1, the 0.1C discharge capacity of Comparative Example 1 is close to that of Example 1, but its 1C discharge capacity is only half that of Example 1, indicating poor high-rate performance. Furthermore, regardless of whether it's at 0.1C or 1C, the cycle performance of Comparative Example 1 is far lower than that of Example 1. This is because the amount of PEO added in Comparative Example 1 is very high, leading to a reaction imbalance in the lithium-ion storage station. Comparing Example 1 with Comparative Example 2, which did not add ZnO and whose other parameters are the same as Example 1, the 0.1C discharge capacity of Comparative Example 2 is close to that of Example 1, but its 1C discharge capacity is significantly different, exhibiting only some high-rate performance. However, its cycle performance still lags far behind that of Example 1. Therefore, the lithium-ion storage station in Comparative Example 2 did not experience a reaction imbalance. The reaction system can still operate smoothly even without ZnO, but without ZnO catalysis, the cycle performance cannot be significantly improved. Comparing Comparative Example 3 with Examples 1 and 1, Comparative Example 3 uses a lithium-rich manganese-based cathode material without modification to construct an interface control layer and lithium-ion storage station. The 0.1C discharge capacity of Comparative Example 3 is close to that of Example 1 and almost identical to that of Comparative Example 1, but the 1C discharge capacity is less than half that of Example 1 and slightly lower than that of Comparative Example 1, indicating very poor high-rate performance. Regardless of whether it is at 0.1C or 1C, the cycle performance of Comparative Example 3 is significantly lower than that of Comparative Example 1. It can be seen that even under reaction imbalance, the lithium-ion storage station can still significantly improve the cycle performance. In summary, the preparation method of the present invention brings a significant performance improvement to the composite cathode material and achieves remarkable progress.

[0046] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a high-rate lithium-rich manganese-based composite cathode material, characterized in that: It includes the following steps: (1) Preparation of lithium-rich manganese-based core 0.08 mol Ni(NO3)2·6H2O, 0.08 mol Co(NO3)2·6H2O, 0.64 mol Mn(NO3)2·4H2O, and 0.012 mol KNO3 were dissolved in 100 mL of deionized water. 20 g of acrylic acid aqueous solution was added and mixed thoroughly. Then, 1.188 mol LiNO3 was added and stirred for 20-40 min to obtain a first mixed solution. An inert gas was bubbled into the first mixed solution for 10-30 min, and 0.3 g of ammonium persulfate was added. A polymerization reaction was initiated at 70 °C for 3 h to obtain a polymer precursor. The polymer precursor was then kept at 500 °C for 4-6 h, followed by calcination at 800-1200 °C for 12-16 h to obtain lithium-rich manganese-based core particles with the chemical formula Li. 1.188 K 0.012 Ni 0.1 Co 0.1 Mn 0.8 O2; (2) Constructing the interface control layer 5g of lithium-rich manganese-based core particles obtained in step (1) were dispersed in 50mL of ethanol solution. 0.1-0.2g of graphene, 0.05-0.1g of carbon nanotubes, and 0.0075-0.015g of LiNO3 were added. After ultrasonic dispersion for 30-60min, the mixture was stirred and dried at 40-60℃ for 5-7h to obtain Li-coated core particles. + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers; (3) Constructing a lithium-ion storage station The Li-coated product obtained in step (2) + Lithium-rich manganese-based core particles doped with graphene / carbon nanotube layers were dispersed in 50 mL of N,N-dimethylformamide solution, and 0.2-0.5 g of LATP powder, 0.3-0.8 g of PEO and 0.01-0.05 g of ZnO powder were added. After ultrasonic dispersion for 90 min, the mixture was spin-coated at 3000 r / min for 45 s, and then vacuum dried at 100-120 °C for 9-15 h to obtain a lithium-rich manganese-based composite cathode material with LATP / PEO composite storage station coated on its surface.

2. The method for preparing high-rate lithium-rich manganese-based composite cathode material according to claim 1, characterized in that: In step (1), the mass fraction of acrylic acid in the acrylic acid aqueous solution is 50%.

3. The method for preparing high-rate lithium-rich manganese-based composite cathode material according to claim 1, characterized in that: In step (2), the Li + The thickness of the doped graphene / carbon nanotube layer is 10-30 nm.

4. The method for preparing high-rate lithium-rich manganese-based composite cathode material according to claim 1, characterized in that: In step (3), the thickness of the LATP / PEO composite storage station is 60 nm.

5. The method for preparing high-rate lithium-rich manganese-based composite cathode material according to claim 1, characterized in that: In step (1), the inert gas is nitrogen.

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