High-voltage platform O2 type lithium-rich manganese-based layered structure material as well as preparation method and application thereof

Abstract

The invention discloses a high-voltage platform O2-type lithium-rich manganese-based layered structure material and a preparation method and application thereof.According to the method, a nanoscale precursor is prepared through a coprecipitation method, microwave calcination and an ion exchange process are combined, material particle size distribution and effective control over a crystal phase are achieved, and the high-voltage platform O2-type lithium-rich manganese-based layered structure material is obtained. Compared with the prior art, the O2-type lithium-rich manganese-based cathode material has the advantages that the discharge voltage platform of the O2-type lithium-rich manganese-based cathode material is effectively improved, meanwhile, the discharge stability of the O2-type lithium-rich manganese-based cathode material under a high voltage platform is improved, the prepared O2-type lithium-rich manganese-based cathode material is excellent in electrochemical performance, the discharge voltage platform of the O2-type lithium-rich manganese-based cathode material is 4.5 V or above and is in the voltage range of 2.0-4.8 V, and when the charge-discharge rate is 0.1 C, the discharge stability of the O2-type lithium-rich manganese-based cathode material is greatly improved. The first discharge capacity reaches 240-260 mAh.g <-1 >, the specific discharge capacity after 10 times of cycle performance is 235-255 mAh.g <-1 >, and a voltage platform can appear at 4.5 V or above.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion battery positive electrode materials, and relates to a high-voltage platform O2-type lithium-manganese-rich matrix structural material, a preparation method and an application thereof. Background Art

[0002] Batteries, as important devices for electrochemical energy storage, have been widely used and rapidly developed since their introduction. Lithium-ion batteries, as a major new energy product, are important mobile energy storage devices. Their advantages, such as high energy density, no memory effect, minimal self-discharge, and long cycle life, have led to their widespread application in a wide range of fields, from smartwatches to electric vehicles that combine both power and capacity. However, with the development of related technologies such as mobile energy storage and power batteries, people are placing higher demands on the energy density, rate capability, endurance, cost, and safety of lithium-ion batteries. Lithium-ion batteries primarily consist of four parts: a positive electrode, a negative electrode, a separator, and an electrolyte. Among these, the positive electrode material is the key component that primarily influences the performance of lithium-ion batteries. Therefore, improving the performance of lithium-ion battery positive electrode materials has significant value and practical significance in multiple dimensions, including technological advancement, industrial development, energy transition, and social livelihoods.

[0003] Lithium-rich manganese-based cathode materials Li[Li 0.2 Ni x Co y Mn 0.8-x-y ]O 2+Δ (0.60≤x≤0.80; 0.00≤y≤0.40, referred to as LNMO, space P63mc), because lithium-rich manganese-based layered oxide has high energy density (theoretical capacity>250mAh·g -1 ), a wide voltage range (2.0-4.8V), and other characteristics, and has become a key material for the next generation of new energy vehicle batteries. Although lithium-rich manganese materials show a discharge specific capacity higher than the theoretical capacity, the traditional solid-phase prepared lithium-rich manganese is of the O3 type. Above 4.5V, oxygen activity causes changes in the oxygen framework structure and cation migration, and there is also the release of lattice oxygen, resulting in significant voltage decay and cycle capacity decline during the cycle. These problems have inhibited the commercial application of lithium-rich manganese materials. The O2-type lithium-rich manganese material uses ABAC oxygen layer stacking. Due to the unique O stacking method, a more open ion channel is formed, which can promote the reversibility of cation migration and effectively solve the voltage decay problem during the cycle. This is mainly due to the adjustment of the oxygen framework. Therefore, improving the chemical stability of the oxygen framework is the key to improving the electrochemical performance of lithium-rich manganese positive electrode materials. However, the existing O2-type lithium-rich manganese positive electrode materials have a low discharge voltage platform, poor stability at high discharge voltage platforms, and shortened lifespan, which greatly limits the widespread application of lithium-rich manganese materials in the new energy field. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a high-voltage platform O2-type lithium-rich manganese-based matrix structure material and its preparation method and application, thereby solving the technical problems in the prior art that the O2-type lithium-rich manganese-based positive electrode material has a low discharge voltage platform and poor stability under a high discharge voltage platform.

[0005] The present invention is achieved through the following technical solutions: rapid microwave sintering can be used for heating, and direct heating inside the material can achieve heating uniformity, making the material structure stable, and secondly shortening the time to reduce element segregation, so as to reduce unit cell defects.

[0006] A method for preparing a high-voltage platform O2-type lithium-rich manganese-based matrix structure material comprises the following steps:

[0007] S1: mixing nickel salt, manganese salt and / or cobalt salt to prepare a mixed salt solution, mixing the mixed salt solution with a complexing agent solution and a precipitant solution, stirring and reacting to prepare a precursor material;

[0008] S2: After the precursor material and the sodium source are uniformly mixed, the mixture is placed in a microwave calcining furnace and pre-calcined at a first temperature, followed by heating and then re-calcining at a second temperature to obtain a sodium-ion P2 intermediate phase material;

[0009] S3: After uniformly mixing the sodium-ion battery P2 intermediate phase material and lithium salt, heat treatment is performed at 200-350° C. to obtain the high-voltage platform O2-type lithium-rich manganese-based matrix structure material.

[0010] Preferably, in step S1, the concentration of the mixed salt solution is 0.5-3 mol / L, the concentration of the precipitant solution is 2-6 mol / L; and the volume ratio of the precipitant solution to the mixed salt solution is 1:(0.5-12).

[0011] Preferably, in step S1, the mixed salt solution is mixed with the complexing agent solution and the precipitant solution, specifically by injecting the mixed salt solution and the complexing agent solution into water respectively using a peristaltic pump, and injecting the precipitant solution simultaneously using a peristaltic pump;

[0012] During the injection process, the flow rate of the mixed salt solution is 1.5-15 mL / min, the flow rate of the complexing agent solution is 2-8 mL / min, and the flow rate of the precipitant solution is controlled to keep the pH value of the system at 8-12.

[0013] Preferably, in step S1, during the stirring reaction, the stirring rate is 300-700 r / min and the reaction temperature is 45-75°C.

[0014] Preferably, the precipitant solution is a sodium hydroxide solution or a sodium carbonate solution, and when the precipitant solution is a sodium hydroxide solution, nitrogen is continuously introduced into the reaction system when the mixed salt solution is mixed with the complexing agent solution and the precipitant solution.

[0015] Preferably, in step S2, when the precursor material is mixed with the sodium source, the molar ratio of the transition metal atoms in the precursor to the sodium atoms in the sodium source is 1:(0.6-1).

[0016] Preferably, in step S2, when the pre-calcination treatment is performed at the first temperature, the pre-calcination temperature is 400-600°C and the time is 1-12 hours; when the re-calcination treatment is performed at the second temperature, the calcination temperature is 700-1000°C and the time is 1-20 hours.

[0017] Preferably, in step S3, when the sodium-electrolyte P2 intermediate phase material is mixed with the lithium salt, the molar ratio of sodium atoms in the sodium-electrolyte P2 intermediate phase material to lithium atoms in the lithium salt is 1:(1-12).

[0018] A high-voltage platform O2 type lithium-rich manganese-based matrix structural material is prepared by the above method; the particle size of the high-voltage platform O2 type lithium-rich manganese-based matrix structural material is 1 to 4 μm.

[0019] The above-mentioned high-voltage platform O2-type lithium-rich manganese-based layered structure material is used in the positive electrode material of lithium-ion batteries. The discharge voltage platform of the high-voltage platform O2-type lithium-rich manganese-based layered structure material is above 4.5V and within the voltage range of 2.0 to 4.8V. The high-voltage platform O2-type lithium-rich manganese-based layered structure material has an initial discharge specific capacity of 240 to 260 mAh·g at a charge and discharge rate of 0.1C. -1 The discharge capacity after 10 cycles is 235-255 mAh g -1 .

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] The present invention discloses a method for preparing a high-voltage platform O2-type lithium-rich manganese-based matrix structure material:

[0022] This method first prepares a uniformly distributed transition metal salt precursor through a coprecipitation reaction. During the coprecipitation reaction, the addition of a complexing agent can slow down the release rate of metal ions and prevent particle agglomeration caused by local oversaturation, thereby obtaining a precursor with uniform particle size and good dispersion. At the same time, the addition of a complexing agent can effectively inhibit the Mn 2+ Oxidized to Mn 3+ , and generate mixed phases such as MnOOH. The uniformly distributed transition metal salt precursor helps to form a material with uniform structure and stable performance;

[0023] Secondly, microwave heating is used to prepare sodium-ion battery P2 mesophase materials. The uniformity of microwave heating is better, which improves the uniformity of the mesophase material and significantly reduces the internal thermal stress of the material. The crystal structure of the P2-type sodium-ion battery mesophase is more complete, and the layered order is improved. This avoids lattice defects and impurity formation caused by local overheating, reduces impurities, and ensures the reversibility of the oxygen redox reaction under high pressure, thereby effectively improving the discharge voltage platform.

[0024] Finally, the sodium-ion battery P2 intermediate phase was converted into an O2-type lithium-rich manganese-based material through a low-temperature molten salt ion exchange method at 200-350°C. The low-temperature conditions avoided the irreversible loss of lattice oxygen during lithium insertion and inhibited structural collapse during high-voltage cycling. At the same time, the molten salt environment promoted the rapid diffusion of lithium ions, forming a uniform lithium distribution, reducing local stress concentration, and improving structural stability.

[0025] In summary, the method prepares nanoscale precursors by coprecipitation, combines microwave calcination and ion exchange processes, realizes effective control of material particle size distribution and crystal phase, effectively improves the discharge voltage platform of O2-type lithium-rich manganese-based layered materials, and simultaneously improves the discharge stability of O2-type lithium-rich manganese-based layered materials under high voltage platforms. The O2-type lithium-rich manganese-based cathode material prepared by the present invention has excellent electrochemical performance, with a discharge voltage platform above 4.5V, and within the voltage range of 2.0-4.8V, at a charge and discharge rate of 0.1C, the first discharge capacity reaches 240-260mAh·g -1 The discharge capacity after 10 cycles is 235-255 mAh g -1 , a voltage platform may appear above 4.5V.

[0026] Furthermore, in step S1, the concentration of the mixed salt solution is 0.5 to 3 mol / L, and the concentration of the precipitant solution is 2 to 6 mol / L; the volume ratio of the precipitant solution to the mixed salt solution is 1:(0.5 to 12), and the concentration of the mixed salt solution is limited to 0.5 to 3 mol / L. Too low a concentration leads to insufficient metal ions, slow reaction rate and discontinuous products, affecting structural uniformity; too high a concentration causes local ion supersaturation, resulting in particle agglomeration and widening of the particle size distribution. The concentration of the precipitant solution is set to 2 to 6 mol / L, which can maintain mild reaction conditions and generate precursor particles with moderate crystallinity, which is conducive to maintaining the subsequent calcination morphology. The volume ratio of the precipitant solution to the mixed salt solution is 1:(0.5 to 12). This ratio can balance the reaction rate and product dispersibility, avoid abnormal particle aggregation, and under the synergistic effect of the three, the prepared precursor has uniform particle size and good dispersibility, providing a stable foundation for subsequent calcination and ion exchange, and ensuring the high voltage platform and cycle stability of the O2-type lithium-rich manganese-based material.

[0027] Furthermore, in step S1, the mixed salt solution is mixed with the complexing agent solution and the precipitant solution, specifically: the mixed salt solution and the complexing agent solution are respectively injected into the water using a peristaltic pump, and the precipitant solution is injected using a peristaltic pump at the same time; during the injection process, the flow rate of the mixed salt solution is 1.5 to 15 mL / min, the flow rate of the complexing agent solution is 2 to 8 mL / min, and the flow rate of the precipitant solution is controlled so that the pH value of the system is 8 to 12. In this process, the flow rate is precisely controlled by flexible tube extrusion to ensure that the metal ions, complexing agent and precipitant are in stable contact in proportion, forming a uniform concentration field, and avoiding particle agglomeration or heterogeneous phase generation caused by local oversaturation. Among them, the mixed salt flow rate controls the metal ion concentration gradient to ensure the uniformity and crystallinity of the precursor particle size; the complexing agent flow rate regulates the metal release rate, suppresses local oversaturation by forming a stable complex, and improves the stability of the chemical composition; the pH value range of 8 to 12 ensures that the precipitation reaction is mild and controllable, and promotes uniform growth of the crystal nucleus. The synergistic effect of the three can prepare precursor particles with narrow particle size distribution and regular morphology, laying the structural foundation for the subsequent high-temperature synthesis of high-performance materials.

[0028] Furthermore, in step S1, during the stirring reaction, the stirring rate is 300 to 700 r / min, and the reaction temperature is 45 to 75° C. An appropriate stirring rate can promote uniform mixing and reaction of the raw materials while controlling particle morphology and agglomeration. An appropriate reaction temperature can regulate the reaction rate and product crystallinity while optimizing the structure and properties of the precursor, preventing lattice defects and impurity formation, optimizing the structure and properties of the precursor, and promoting orderly crystal growth.

[0029] Furthermore, the precipitant solution is a sodium hydroxide solution or a sodium carbonate solution, and when the precipitant solution is a sodium hydroxide solution, when the mixed salt solution is mixed with the complexing agent solution and the precipitant solution, nitrogen is continuously introduced into the reaction system to ensure the purity of the product.

[0030] Furthermore, in step S2, when the precursor material is mixed with a sodium source, the molar ratio of the transition metal atoms in the precursor to the sodium atoms in the sodium source is 1: (0.6 to 1). By controlling this ratio, a stable layered structure can be constructed. The appropriate sodium content can ensure that the sodium ions are arranged in an orderly manner between the layers, avoiding the collapse of the layered structure due to too low a sodium content, or the sodium content being too high causing the sodium ions to occupy the transition metal sites, thereby destroying the structural stability. At the same time, this ratio can regulate the distribution of sodium ions, regulate the sodium ion diffusion channels, and improve the ion conductivity. When the sodium content is 0.6 to 1, there is enough space for the sodium ions to diffuse between the layers, and the transition metal layer can also provide a certain support effect to prevent the interlayer spacing from being too large and causing the structure to be loose.

[0031] Furthermore, in step S2, when pre-calcination treatment is carried out at a first temperature, the pre-calcination temperature is 400-600°C, and the time is 1-12 hours; when re-calcination treatment is carried out at a second temperature, the calcination temperature is 700-1000°C, and the time is 1-20 hours. Step S2 adopts a two-stage calcination process to optimize the material structure and purity: in the pre-calcination stage (400-600°C, 1-12 hours), impurities such as moisture, organic complexing agent, carbonate and hydroxide in the precursor are removed by thermal decomposition, and volatilized in the form of H2O and CO2 gases to avoid structural damage caused by impurity decomposition during high-temperature calcination, while promoting the initial formation of an ordered crystal framework between transition metal ions and oxygen, thereby improving the material purity; in the high-temperature calcination stage (700-1000°C, 1-20 hours), a complete layered structure is formed through full ion diffusion, lattice defects are reduced, and the crystallinity and morphology regularity are improved, ultimately achieving a dual improvement in crystal structure optimization and electrochemical performance.

[0032] Furthermore, in step S3, when the sodium-ion P2 intermediate phase material is mixed with the lithium salt, the molar ratio of sodium atoms in the sodium-ion P2 intermediate phase material to lithium atoms in the lithium salt is 1:(1 to 12). This ratio realizes efficient sodium-lithium ion exchange, can construct a stable layered structure, and also realizes the orderliness control of the layered structure. Moreover, this ratio can realize the regulation of material composition and phase composition, thereby realizing the optimization of electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a scanning electron microscope (SEM) image of the hydroxide precursor prepared in Example 1 of the present invention;

[0035] Figure 2 This is the X-ray diffraction (XRD) spectrum of the O2-type lithium-rich manganese cathode material prepared in Example 1 of the present invention;

[0036] Figure 3 This is an SEM image of the carbonate precursor material prepared in Example 2 of the present invention;

[0037] Figure 4 This is a SEM image of the O2-type lithium-rich manganese positive electrode material prepared in Example 2 of the present invention;

[0038] Figure 5 This is a capacity and average voltage cycle diagram of the O2-type lithium-rich manganese positive electrode material prepared in Example 2 of the present invention;

[0039] Figure 6 This is a SEM image of the O2-type lithium-rich manganese positive electrode material prepared in Example 3 of the present invention;

[0040] Figure 7 This is the first charge and discharge curve of the O2-type lithium-rich manganese cathode material prepared in Example 4 of the present invention;

[0041] Figure 8 This is the XRD spectrum of the O2-type lithium-rich manganese positive electrode material prepared in Example 5 of the present invention;

[0042] Figure 9 This is the first charge and discharge curve of the O2-type lithium-rich manganese cathode material prepared in Example 5 of the present invention;

[0043] Figure 10 This is a capacity and average voltage cycle diagram of the O2-type lithium-rich manganese positive electrode material prepared in Example 6 of the present invention. DETAILED DESCRIPTION

[0044] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0045] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0046] Herein, all features such as values, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0047] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0048] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0049] The present invention discloses a method for preparing a high-voltage platform O2-type lithium-rich manganese-based matrix structure material, comprising the following steps:

[0050] S1: According to the chemical formula Li[Li 0.2 Ni x Mn y Co 0.8-x-y ]O 2+Δ (0.00<x≤0.40; 0.60≤y≤0.80; the value of Δ is selected so that the chemical formula ensures electrical neutrality) Weigh an appropriate amount of nickel salt, manganese salt and / or cobalt salt, add deionized water and stir to fully dissolve and mix, that is, mix the nickel salt, manganese salt and / or cobalt salt to prepare a mixed salt solution with a concentration of 0.5-3 mol / L, that is, a transition metal salt solution, and mix the mixed salt solution with a complexing agent solution with a concentration of 1-6 mol / L and a precipitant solution with a concentration of 2-6 mol / L. During the mixing process, stir and react at a stirring rate of 300-700 r / min, the reaction temperature is 45-75° C., and the reaction time is 4-20 h. The obtained powder is filtered, washed, and dried to prepare a precursor material;

[0051] The above mixing process is specifically as follows: 1 to 3 L of deionized water is added to a 10 L reactor as a reaction base liquid to help mix the components evenly, and the mixed salt solution and the complexing agent solution are respectively injected into the reactor using a peristaltic pump, and the precipitant solution is injected using a peristaltic pump at the same time; during the injection process, the flow rate of the mixed salt solution is 1.5 to 15 mL / min, and the flow rate of the complexing agent solution is 2 to 8 mL / min. At the same time, the flow rate of the precipitant solution is controlled to make the pH value of the system 8 to 12. Here, by controlling the flow rate of the precipitant solution, on the one hand, the precipitation of the mixed salt is achieved to obtain the precursor material, and on the other hand, the pH value of the system can be controlled.

[0052] The volume ratio of the precipitant solution to the mixed salt solution is 1:(0.5-12);

[0053] The nickel salt is one of NiSO4·6H2O, Ni(CH3COO)2·4H2O, Ni(NO3)2·6H2O and NiCl2·6H2O;

[0054] The manganese salt is one of MnSO4·H2O, Mn(CH3COO)2·4H2O, Mn(NO3)2·4H2O and MnCl2·4H2O;

[0055] The cobalt salt is one of CoSO4·7H2O, Co(CH3COO)2·4H2O, Co(NO3)2·6H2O and CoCl2·6H2O;

[0056] The complexing agent is an aqueous ammonia solution;

[0057] The precipitant solution is a sodium hydroxide solution or a sodium carbonate solution; and when the precipitant solution is a sodium hydroxide solution, when the mixed salt solution is mixed with the complexing agent solution and the precipitant solution, nitrogen is continuously introduced into the reaction system to expel oxygen in the reaction system, thereby avoiding the mixing of carbonate impurities into the precursor material and ensuring the high purity of the material and the stability of subsequent electrochemical performance.

[0058] S2: The precursor material is mixed with a sodium source, wherein the molar ratio of the transition metal atoms in the precursor to the sodium atoms in the sodium source is 1: (0.6-1), and then placed in a microwave calcining furnace, pre-calcined at a first temperature in an oxygen atmosphere, the pre-calcined temperature is 400-600 ° C, the time is 1-12 hours, and then heated, and then calcined again at a second temperature, the temperature of the re-calcined treatment is 700-1000 ° C, and the time is 1-20 hours, to obtain a sodium electrode P2 intermediate phase material Na 0.9 Ni x Mn y Co 1-x-y O 2+Δ ;

[0059] The sodium source here is Na2CO3 or NaOH.

[0060] The oxygen atmosphere here can be oxygen or air.

[0061] S3: The sodium-ionized P2 intermediate phase material is mixed with a lithium salt, wherein the molar ratio of sodium atoms in the sodium-ionized P2 intermediate phase material to lithium atoms in the lithium salt is 1:(1-12), and then heat-treated at 200-350°C for 1-8 hours to perform ion exchange in which Li replaces Na. The product is repeatedly washed with deionized water and alcohol until neutral, and then dried at 120°C for 24 hours to obtain the high-voltage platform O2-type lithium-rich manganese-based matrix structure material Li[Li 0.2 Ni x Mn y Co 0.8-x-y ]O 2+Δ (0.00<x≤0.40; 0.60≤y≤0.80; the value of Δ is selected so that the chemical formula ensures electrical neutrality).

[0062] The lithium salt here is at least one of LiNO3, LiCl and LiMoO4.

[0063] The present invention also discloses a high-voltage platform O2-type lithium-rich manganese-based matrix structure material prepared by the above method. The high-voltage platform O2-type lithium-rich manganese-based matrix structure material is granular, and the particle size of the high-voltage platform O2-type lithium-rich manganese-based matrix structure material is 1 to 4 μm.

[0064] In addition, the present invention also discloses the use of a high-voltage platform O2-type lithium-rich manganese-based layered structure material prepared by the method of the present invention in a lithium-ion battery positive electrode material. The discharge voltage platform of the high-voltage platform O2-type lithium-rich manganese-based layered structure material is above 4.5V and within the voltage range of 2.0 to 4.8V. The high-voltage platform O2-type lithium-rich manganese-based layered structure material has an initial discharge specific capacity of 240 to 260 mAh·g at a charge and discharge rate of 0.1C. -1 The discharge capacity after 10 cycles is 235-255 mAh g -1 .

[0065] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0066] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0067] Example 1

[0068] In this embodiment, according to the chemical formula Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2.1 Ingredients

[0069] An O2-type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2.1 The preparation method comprises the following steps:

[0070] Step 1. Solution preparation:

[0071] According to the molar ratio of nickel to manganese elements of 0.2:0.6, NiSO4·6H2O and MnSO4·H2O were weighed respectively, and deionized water was added and stirred to fully dissolve to prepare a 2 mol / L transition metal salt solution, i.e., a mixed salt solution; sodium hydroxide solid was weighed and deionized water was added to fully dissolve to prepare a precipitant solution with a concentration of 4 mol / L; an appropriate amount of concentrated ammonia water was taken and diluted to 4 mol / L with deionized water to prepare an ammonia buffer solution as a complexing agent.

[0072] Step 2. Co-precipitation:

[0073] Before the reaction began, 1.5 L of deionized water was added to a 10 L reactor as a base liquid, followed by nitrogen gas to expel oxygen from the reactor. A peristaltic pump was used to inject a transition metal salt solution and an ammonia buffer solution into the reactor from the feed port at feed rates of 1.5 mL / min and 2 mL / min, respectively. The sodium hydroxide solution feed rate was simultaneously controlled to maintain a pH of 12. The volume ratio of the precipitant solution to the mixed salt solution was 1:1. The reaction temperature was controlled at 60°C, and the stirrer speed was 400 rpm. After 20 hours of reaction, the resulting product was filtered, washed, and dried to obtain a hydroxide precursor material.

[0074] Step 3. Calcination:

[0075] The hydroxide precursor material obtained in step 2 was mixed with Na2CO3, wherein the molar ratio of transition metal atoms in the precursor material to sodium atoms in Na2CO3 was 1:0.6. The mixture was placed in a ball mill and mixed evenly. Then, the mixture was placed in a microwave sintering furnace and pre-sintered at 600°C for 6 hours in an air atmosphere. Then, the temperature was raised to 800°C and calcined again for 16 hours to obtain a layered oxide material Na 0.6 Ni 0.25 Mn 0.75 O 2.175 , that is, sodium-electrolyte P2 intermediate phase material;

[0076] Step 4. High temperature molten salt

[0077] The layered oxide material Na obtained in step 3 0.9 Ni 0.25 Mn 0.75 O 2.175 The mixture was uniformly mixed with LiNO3 in a molar ratio of Na atoms to Li atoms of 1:12, and then placed in a muffle furnace filled with oxygen atmosphere, and heat-treated at 350 ° C for 1 h. The obtained powder was then repeatedly washed with deionized water and alcohol, and dried to obtain the O2-type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2.1 .

[0078] The hydroxide precursor material prepared in this embodiment is in the form of secondary particles, which are spherical. Figure 1 As shown, the secondary particle size is about 15 μm. The O2-type lithium-rich manganese cathode material prepared in this embodiment is spherical, and the secondary particle size is about 4 μm. The XRD spectrum shows that the prepared sample has a typical O2 phase structure, as shown in FIG. Figure 2 As shown, the space group is P63mc.

[0079] The charge and discharge performance test process of the positive electrode material prepared in this embodiment is as follows:

[0080] The prepared O2-structured cathode material, acetylene black, and binder polyvinylidene fluoride (PVDF) were weighed in a mass ratio of 8:1:1 and added to N-methylpyrrolidone (NMP) to form a slurry. The slurry was evenly coated on aluminum foil and dried in a vacuum oven at 80°C for 12 hours. Subsequently, the electrodes (12 mm in diameter) were cut using a mold. CR2032 button-type cells were assembled in an argon-filled glove box using a lithium metal sheet as the negative electrode, a polypropylene film (Celgard 2400) as the separator, and LP30 as the electrolyte.

[0081] The electrochemical performance of the battery was tested at different charge and discharge rates in the voltage range of 2.0 to 4.8 V. The results showed that the O2-type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2.1 At a charge and discharge rate of 0.1C (1C = 252 mA g -1 The first charge and discharge capacity at the rate of 252 mAh g -1 and 251mAh·g -1 After 10 cycles at a rate of 0.1C, the capacity retention rate was 96.8%, and the average voltage drop per cycle was about 3.0mV.

[0082] Example 2

[0083] In this embodiment, according to the chemical formula Li[Li 0.2 Ni 0.26 Mn 0.5 Co 0.04 ]O 2.05 Ingredients.

[0084] A method for preparing an O2-type lithium-rich manganese positive electrode material comprises the following steps:

[0085] Step 1. Solution preparation:

[0086] According to the molar ratio of nickel, manganese and cobalt elements of 0.26:0.49:0.04, three salts of Ni(CH3COO)2·4H2O, Mn(CH3COO)2·4H2O and Co(CH3COO)2·4H2O were weighed respectively, and ionized water was used to prepare a 0.5 mol / L mixed salt solution; Na2CO3 was weighed to prepare a precipitant solution with a concentration of 2 mol / L; concentrated ammonia water was diluted to a 1 mol / L ammonia solution with deionized water.

[0087] Step 2. Co-precipitation:

[0088] 2L of deionized water was added to a 10L reactor as the base liquid, and a peristaltic pump was used to inject the transition metal salt solution and ammonia solution into the reactor from the feed port at feed rates of 15mL / min and 8mL / min, respectively. At the same time, the feed rate of the precipitant solution was regulated to control the pH value of the solution in the reactor to 8. The volume ratio of the precipitant solution to the mixed salt solution was 1:4, the reaction temperature was controlled at 50°C, and the agitator speed was 600r / min. After reacting for 4h, the product obtained in the reactor was filtered, washed, and dried to obtain a carbonate precursor material.

[0089] Step 3. Calcination:

[0090] The carbonate precursor material obtained in step 2 is mixed with Na2CO3, wherein the molar ratio of the transition metal atoms in the carbonate precursor material to the sodium atoms in Na2CO3 is 1:0.7. The mixture is placed in a ball mill and mixed evenly. Then, the mixture is placed in a microwave sintering furnace and pre-sintered at 400°C for 12 hours. After the pre-sintering, the powder is mixed evenly and placed in a microwave sintering furnace again and calcined at 700°C for 20 hours to obtain a layered oxide material Na 0.7 Ni 0.33 Mn 0.62 Co 0.05 O 2.16 .

[0091] Step 4. High temperature molten salt

[0092] The layered oxide material Na obtained in step 3 0.7 Ni 0.33 Mn 0.62 Co 0.05 O 2.16 The mixture was uniformly mixed with LiCl in a molar ratio of Na:Li of 1:6, and then calcined in a muffle furnace and heat-treated at 300 ° C in an oxygen atmosphere for 3 h to carry out ion exchange reaction. The obtained powder material was washed alternately with distilled water and anhydrous ethanol, and dried to obtain the O2-type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.26 Mn 0.5 Co 0.04 ]O2.05 .

[0093] The SEM image of the carbonate precursor material prepared in this embodiment is as follows: Figure 3 As shown in the figure, the carbonate precursor is spherical and the secondary particle size is in the range of 5 to 10 μm; the SEM image of the O2-type lithium-rich manganese cathode material sample is as follows. Figure 4 As shown in the figure, it can be seen that the secondary particle size is about 2μm.

[0094] Battery assembly and charge-discharge performance test: The battery assembly and battery charge-discharge test methods are the same as in Example 1. The test results are as follows: Figure 5 As shown in the figure, the first discharge specific capacity of the O2-type lithium-rich manganese positive electrode material prepared in the embodiment of the present invention at 0.1C is 241mAh·g -1 After 10 cycles of performance testing, the capacity is 235.5 mAh g -1 , the 10-cycle retention rate is 97.7%, and the average voltage decay is about 3.0mV.

[0095] Example 3

[0096] In this embodiment, according to the chemical formula Li[Li 0.2 Ni 0.26 Mn 0.46 Co 0.08 ]O2 ingredients.

[0097] A method for preparing an O2-type lithium-rich manganese positive electrode material comprises the following steps:

[0098] Step 1. Solution preparation:

[0099] According to the molar ratio of nickel, manganese and cobalt elements of 0.26:0.46:0.08, three salts of Ni(NO3)2·6H2O, Mn(NO3)2·4H2O and Co(NO3)2·6H2O were weighed respectively, and deionized water was added to prepare a 2 mol / L transition metal salt solution; sodium hydroxide solid was weighed and prepared with deionized water to prepare a precipitant solution with a concentration of 6 mol / L; concentrated ammonia water was diluted with deionized water to a 6 mol / L ammonia solution.

[0100] Step 2. Co-precipitation:

[0101] A 10L reactor was filled with 1L of deionized water, and nitrogen was continuously introduced to expel oxygen. A transition metal salt solution and an ammonia solution were injected into the reactor via a peristaltic pump at feed rates of 1.5mL / min and 2.0mL / min, respectively. The precipitant solution feed rate was simultaneously adjusted to maintain a pH of 11. The volume ratio of the precipitant solution to the transition metal salt solution was 1:6. The reaction temperature was maintained at 60°C, and the agitator speed was maintained at 300 rpm. After an 8-hour reaction, the product obtained from the reactor was filtered, washed, and dried to obtain a hydroxide precursor material.

[0102] Step 3. Calcination:

[0103] The hydroxide precursor material obtained in step 2 is mixed with NaOH, wherein the molar ratio of the transition metal atoms in the hydroxide precursor material to the sodium atoms in NaOH is 1:0.8. The mixture is mixed evenly and placed in a microwave sintering furnace, and pre-sintered at 600°C for 12 hours. After the pre-sintering is completed, the powder is mixed evenly and placed in a microwave sintering furnace again, and calcined in air at 1000°C for 1 hour to obtain a layered oxide material Na 0.8 Ni 0.33 Mn 0.57 Co 0.1 O 2.185 , that is, sodium-ion P2 intermediate phase material.

[0104] Step 4. High temperature molten salt

[0105] The layered oxide material Na obtained in step 3 0.8 Ni 0.33 Mn 0.57 Co 0.1 O 2.185 Mixed evenly with LiNO3 and LiCl (the molar ratio of LiNO3 to LiCl is 88:12), the layered oxide material Na 0.8 Ni 0.33 Mn 0.57 Co 0.1 O 2.185 The molar ratio of Na to LiNO3 and Li in LiCl is 1:4, and then it is placed in a muffle furnace for calcination, and ion exchange is carried out in air at 250 ° C for 8 hours. The obtained powder material is repeatedly washed with deionized water and anhydrous ethanol, and dried to obtain the O2 type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.26 Mn 0.46 Co 0.08 ]O2.

[0106] The morphology of the O2-type lithium-rich manganese cathode material prepared in this example is shown in FIG. Figure 6It can be seen from the figure that the particles are spherical agglomerates, and the size range of the O2-type lithium-manganese-rich positive electrode material is 4μm.

[0107] Battery assembly and charge-discharge performance test: The battery assembly and battery charge-discharge test methods are the same as those in Example 1. The results show that the Li[Li 0.2 Ni 0.26 Mn 0.46 Co 0.08 The first discharge capacity of the O2 cathode material at 0.1C is 243 mAh g -1 The capacity retention rate after 50 cycles is 91%, and the average voltage drops by about 3.2mV per cycle in the cycle performance test.

[0108] Example 4

[0109] In this embodiment, according to the chemical formula Li[Li 0.2 Ni 0.13 Mn 0.54 Co 0.13 ]O 2.07 Ingredients.

[0110] A method for preparing an O2-type lithium-rich manganese positive electrode material comprises the following steps:

[0111] Step 1. Solution preparation:

[0112] According to the molar ratio of nickel, manganese and cobalt elements of 0.13:0.54:0.13, three salts of NiCl2·6H2O, MnCl2·4H2O and CoCl2·6H2O were weighed respectively and deionized water was added to prepare a 2.5 mol / L transition metal salt solution; sodium carbonate solid was weighed and fully dissolved in deionized water to prepare a precipitant solution with a concentration of 5 mol / L; concentrated ammonia water was diluted with deionized water to a 4 mol / L ammonia solution.

[0113] Step 2. Co-precipitation:

[0114] First, 2 L of deionized water was added to a 10 L reactor, and a transition metal salt solution and an ammonia solution were injected into the reactor from the feed port using a peristaltic pump at feed rates of 5.0 mL / min and 3.0 mL / min, respectively. At the same time, the feed rate of the precipitant solution was regulated to control the pH value of the solution in the reactor to 8.5. The volume ratio of the precipitant solution to the transition metal salt solution was 1:0.5, the reaction temperature was controlled at 65 ° C, the agitator speed was 500 r / min, and after 6 hours of reaction, the product obtained in the reactor was filtered, washed, and dried to obtain a carbonate precursor material.

[0115] Step 3. Calcination:

[0116] The carbonate precursor material obtained in step 2 was mixed with NaOH, with the molar ratio of transition metal atoms in the precursor to sodium atoms in NaOH being 1:0.95. The mixture was placed in a ball mill and mixed evenly. The mixture was then placed in a microwave sintering furnace and pre-calcined at 600°C in oxygen for 4 hours, and then calcined at 800°C in oxygen for 12 hours to obtain a layered oxide material Na 0.95 Ni 0.16 Mn 0.68 Co 0.16 O 2.315 .

[0117] Step 4. High temperature molten salt

[0118] The layered oxide material Na obtained in step 3 0.95 Ni 0.16 Mn 0.68 Co 0.16 O 2.315 The mixture was mixed evenly with LiMoO4 in a molar ratio of Na to Li of 1:4, and then placed in a muffle furnace for ion exchange, heated to 280 ° C in an oxygen atmosphere, and calcined for 4 h. The obtained powder material was repeatedly washed with deionized water and anhydrous ethanol, and dried to obtain the O2-type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.13 Mn 0.54 Co 0.13 ]O 2.07 .

[0119] Battery assembly and charge and discharge performance test: The battery assembly and battery charge and discharge test methods are the same as in Example 1. The charge and discharge test results are shown in Figure 7 As can be seen from the figure, the O2-type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.13 Mn 0.54 Co 0.13 ]O 2.07 The first discharge capacity at 0.1C is 262 mAh g -1 The voltage drop of each cycle in the first 10 cycles of charge and discharge is about 0.12V. After 10 cycles of cycle performance test, the discharge capacity is 255.8mAh·g -1 , and has a voltage platform above 4.5V.

[0120] Example 5

[0121] In this embodiment, according to the chemical formula Li[Li 0.2 Ni 0.2 Mn 0.4 Co 0.2 ]O2 ingredients.

[0122] An O2-type lithium-rich manganese Li[Li0.2 Ni 0.2 Mn 0.4 Co 0.2 The preparation method of the O2 positive electrode material comprises the following steps:

[0123] Step 1. Solution preparation:

[0124] According to the molar ratio of nickel, manganese and cobalt elements of 0.2:0.4:0.2, NiSO4·4H2O, MnSO4·H2O and CoSO4·7H2O were weighed respectively, and deionized water was added and stirred to fully dissolve to prepare a 3 mol / L salt solution; sodium hydroxide solid was weighed and added to deionized water to prepare a precipitant solution with a concentration of 6 mol / L; concentrated ammonia water was diluted with deionized water to a 6 mol / L ammonia solution.

[0125] Step 2. Co-precipitation:

[0126] First, 3 L of deionized water was added to a 10 L reactor, and nitrogen was continuously introduced into the reactor to expel oxygen in the reactor. A peristaltic pump was used to inject a transition metal salt solution and an ammonia solution into the reactor from the feed port at feed rates of 1.5 mL / min and 2 mL / min, respectively. At the same time, the feed rate of the sodium hydroxide solution was regulated to control the pH value of the solution in the reactor to 11. The volume ratio of the precipitant solution to the transition metal salt solution was 1:12, the reaction temperature was controlled at 75 ° C, the agitator speed was 500 r / min, and after 15 hours of reaction, the product obtained in the reactor was filtered, washed, and dried to obtain a hydroxide precursor material.

[0127] Step 3. Calcination:

[0128] The hydroxide precursor material obtained in step 2 is mixed with Na2CO3, wherein the molar ratio of transition metal atoms in the hydroxide precursor material to sodium atoms in Na2CO3 is 1:1. The mixture is mixed evenly in a ball mill, and then placed in a microwave sintering furnace, pre-calcined at 500°C for 3h in an air atmosphere, and then heated to 700°C and calcined again for 20h to obtain a layered oxide material NaNi 0.25 Mn 0.5 Co 0.25 O 2.25 .

[0129] Step 4. High temperature molten salt

[0130] The layered oxide material NaNi obtained in step 3 0.25 Mn 0.5 Co 0.25 O 2.25The material and LiCl were mixed evenly in a molar ratio of Na to Li of 1:4, and then calcined in a muffle furnace and ion exchanged in oxygen at 250°C for 6 hours. The obtained powder material was washed thoroughly with deionized water and dried to obtain the O2-type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.2 Mn 0.4 Co 0.2 ]O2.

[0131] The XRD spectrum of the O2-type lithium-rich manganese cathode material prepared in this example is shown in Figure 8 As can be seen from the figure, the O2-type lithium-rich manganese positive electrode material prepared in this embodiment has an O2 phase.

[0132] Battery assembly and charge and discharge performance test: The battery assembly and battery charge and discharge test methods are the same as in Example 1. The charge and discharge test results are shown in Figure 9 As shown in the figure, it can be seen that the Li[Li 0.2 Ni 0.2 Mn 0.4 Co 0.2 The first discharge capacity of the O2 cathode material at 0.1C is 247.5 mAh g -1 The average voltage drop per circle in the first 30 circles is about 2.8mV, and there is a voltage platform above 4.5V.

[0133] Example 6

[0134] In this embodiment, according to the chemical formula Li[Li 0.2 Ni 0.2 Mn 0.4 Co 0.2 ]O2 ingredients.

[0135] An O2-type lithium-rich manganese Li[Li 0.2 Ni 0.2 Mn 0.4 Co 0.2 The preparation method of the O2 positive electrode material comprises the following steps:

[0136] Step 1. Solution preparation:

[0137] According to the molar ratio of nickel, manganese and cobalt elements of 0.2:0.4:0.2, NiSO4·4H2O, MnSO4·H2O and CoSO4·7H2O were weighed respectively, and deionized water was added and stirred to fully dissolve to prepare a 3 mol / L salt solution; sodium hydroxide solid was weighed and added to deionized water to prepare a precipitant solution with a concentration of 6 mol / L; concentrated ammonia water was diluted with deionized water to a 6 mol / L ammonia solution.

[0138] Step 2. Co-precipitation:

[0139] First, 3 L of deionized water was added to a 10 L reactor, and nitrogen was continuously introduced into the reactor to expel oxygen in the reactor. A peristaltic pump was used to inject a transition metal salt solution and an ammonia solution into the reactor from the feed port at feed rates of 1.5 mL / min and 2 mL / min, respectively. At the same time, the feed rate of the sodium hydroxide solution was regulated to control the pH value of the solution in the reactor to 11. The volume ratio of the precipitant solution to the transition metal salt solution was 1:12, the reaction temperature was controlled at 45 ° C, the agitator speed was 700 r / min, and after 15 hours of reaction, the product obtained in the reactor was filtered, washed, and dried to obtain a hydroxide precursor material.

[0140] Step 3. Calcination:

[0141] The hydroxide precursor material obtained in step 2 is mixed with Na2CO3, wherein the molar ratio of transition metal atoms in the hydroxide precursor material to sodium atoms in Na2CO3 is 1:1. The mixture is mixed evenly in a ball mill, and then placed in a microwave sintering furnace, pre-calcined at 600°C for 1h in an air atmosphere, and then heated to 800°C and calcined again for 18h to obtain a layered oxide material NaNi 0.25 Mn 0.5 Co 0.25 O 2.25 .

[0142] Step 4. High temperature molten salt

[0143] The layered oxide material NaNi obtained in step 3 0.25 Mn 0.5 Co 0.25 O 2.25 The material and LiCl were mixed evenly in a molar ratio of Na to Li of 1:1, and then calcined in a muffle furnace and ion exchanged in oxygen at 200°C for 7 hours. The obtained powder material was fully washed with deionized water and dried to obtain the O2-type lithium-rich manganese cathode material Li[Li 0.2 Ni 0.2 Mn 0.4 Co 0.2 ]O2.

[0144] Battery assembly and charge-discharge performance test: The battery assembly and battery charge-discharge test methods are the same as in Example 1. The test results are as follows: Figure 10 As shown in the figure, the first discharge specific capacity of the O2-type lithium-rich manganese cathode material prepared in the embodiment of the present invention at 0.1C is 245.1mAh·g -1 After 10 cycles of performance testing, the capacity is 237mAhg -1 , the 10-cycle retention rate is 96.7%, and the average voltage decay is about 3.1mV.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a high voltage platform O2-type lithium-rich manganese-based matrix structure material, characterized in that: The following steps are involved: S1: mixing nickel salt, manganese salt and / or cobalt salt to prepare a mixed salt solution, mixing the mixed salt solution with a complexing agent solution and a precipitant solution, stirring and reacting to prepare a precursor material; S2: After the precursor material and the sodium source are uniformly mixed, the mixture is placed in a microwave calcining furnace and pre-calcined at a first temperature, followed by heating and then re-calcining at a second temperature to obtain a sodium-ion P2 intermediate phase material; S3: After uniformly mixing the sodium-ion battery P2 intermediate phase material and lithium salt, heat treatment is performed at 200-350° C. to obtain the high-voltage platform O2-type lithium-rich manganese-based matrix structure material.

2. The method for preparing a high voltage platform O2-type lithium-rich manganese-based matrix structure material according to claim 1, characterized in that: In step S1, the concentration of the mixed salt solution is 0.5-3 mol / L, the concentration of the precipitant solution is 2-6 mol / L; and the volume ratio of the precipitant solution to the mixed salt solution is 1:(0.5-12).

3. The method for preparing a high voltage platform O2-type lithium-rich manganese-based matrix structure material according to claim 1, characterized in that: In step S1, the mixed salt solution is mixed with the complexing agent solution and the precipitant solution, specifically: the mixed salt solution and the complexing agent solution are respectively injected into water using a peristaltic pump, and the precipitant solution is injected into water using a peristaltic pump at the same time; During the injection process, the flow rate of the mixed salt solution is 1.5-15 mL / min, the flow rate of the complexing agent solution is 2-8 mL / min, and the flow rate of the precipitant solution is controlled to keep the pH value of the system at 8-12.

4. The method for preparing a high voltage platform O2-type lithium-rich manganese-based matrix structure material according to claim 1, characterized in that: In step S1, during the stirring reaction, the stirring rate is 300-700 r / min and the reaction temperature is 45-75°C.

5. The method for preparing a high voltage platform O2-type lithium-rich manganese-based matrix structure material according to claim 1, characterized in that: The precipitant solution is a sodium hydroxide solution or a sodium carbonate solution. When the precipitant solution is a sodium hydroxide solution, nitrogen is continuously introduced into the reaction system when the mixed salt solution is mixed with the complexing agent solution and the precipitant solution.

6. The method for preparing a high voltage platform O2-type lithium-rich manganese-based matrix structure material according to claim 1, characterized in that: In step S2, when the precursor material is mixed with a sodium source, the molar ratio of transition metal atoms in the precursor to sodium atoms in the sodium source is 1:(0.6-1).

7. The method for preparing a high voltage platform O2-type lithium-rich manganese-based matrix structure material according to claim 1, characterized in that: In step S2, when the pre-calcination treatment is performed at the first temperature, the pre-calcination temperature is 400-600° C. and the time is 1-12 hours; when the re-calcination treatment is performed at the second temperature, the calcination temperature is 700-1000° C. and the time is 1-20 hours.

8. The method for preparing a high voltage platform O2-type lithium-rich manganese-based matrix structure material according to claim 1, characterized in that: In step S3, when the sodium-ion P2 intermediate phase material is mixed with the lithium salt, the molar ratio of sodium atoms in the sodium-ion P2 intermediate phase material to lithium atoms in the lithium salt is 1:(1-12).

9. A high voltage platform O2 type lithium-rich manganese-based matrix structure material, characterized in that: It is prepared by the method according to any one of claims 1 to 8; the particle size of the high-voltage platform O2-type lithium-rich manganese-based matrix structure material is 1 to 4 μm.

10. Application of the high voltage platform O2-type lithium-rich manganese-based matrix structure material as claimed in claim 9 in a positive electrode material for lithium-ion batteries, characterized in that: The discharge voltage platform of the high-voltage platform O2-type lithium-rich manganese-based layered structure material is above 4.5V and within the voltage range of 2.0 to 4.8V. The high-voltage platform O2-type lithium-rich manganese-based layered structure material has an initial discharge specific capacity of 240 to 260 mAh·g at a charge and discharge rate of 0.1C. -1 The discharge capacity after 10 cycles is 235-255 mAh g -1 .

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