Synergistic modified micron-sized O2 type lithium-manganese-rich positive electrode material as well as preparation and application thereof

Abstract

The invention relates to a lithium battery positive electrode material, in particular to a micron-sized O2 type lithium-manganese-rich positive electrode active material, preparation and application in a solid-state lithium battery. The synergistically modified micron-sized O2-type lithium-manganese-rich positive electrode material is an O2-type lithium-manganese-rich positive electrode active material subjected to bulk phase internal doping and external surface modification; wherein the molecular formula of the O2-type lithium-rich manganese positive electrode active material is Li1 (LixMnaTMy) O2, and TM is a transition element Ni and / or Co; the doping element in the bulk phase is one or more of Al, Ti or Zr elements; the external modification is to modify the surface of the active substance through a sulfur source or a fluorine source. The preparation method provided by the invention can realize regulation and control on the bulk phase, surface structure, morphology and particle size of the O2-type lithium-manganese-rich positive electrode material, realizes preparation of the micron-sized O2-type lithium-manganese-rich positive electrode material with a stable structure, enhances good solid-solid interface contact between the positive electrode active material and the inorganic solid electrolyte, inhibits interface side reaction, and improves the performance of the lithium-manganese-rich positive electrode material. The electrochemical performance of the inorganic solid-state lithium battery is favorably improved.

Description

Technical Field

[0001] Technical Field This invention relates to lithium battery cathode materials, specifically to a micron-sized O2-type lithium-rich manganese cathode material with synergistic modification (bulk doping and surface modification), its preparation, and its application in solid-state lithium batteries. Background Technology

[0002] Inorganic solid-state lithium batteries possess the advantages of high specific energy and high safety, making them an advanced technology for developing high-performance lithium batteries. In recent years, research institutions and related companies both domestically and internationally have been vying to invest in this field. As the main source of lithium ions in inorganic solid-state lithium batteries, the type, structure, and electrochemical performance of the cathode material largely determine the energy density, cycle performance, and manufacturing cost of the battery. Therefore, developing low-cost cathode materials with high specific capacity and high voltage is an inevitable choice for developing high-performance inorganic solid-state lithium batteries. Currently, commercially available cathode materials such as LiCoO2, LiFePO4, and NCM mainly provide charge and discharge capacity through the redox reaction of transition metal ions, but they generally suffer from low specific capacity (≤200 mAh / g), making it difficult to further improve their energy density. Therefore, there is an urgent need to develop new cathode materials with higher specific capacity and higher voltage.

[0003] Lithium-rich manganese cathode material x Li2MnO3·(1 -x LiTMO2 (TM = Ni, Mn, Co) possesses a unique cation-anion redox reaction mechanism, exhibiting high cation-anion redox reaction activity at low voltages (≤4.4V, vs. Li). + Li) transition metal ions undergo redox reactions to provide charge / discharge capacity, at high voltages (≥4.4V, vs. Li) +The oxygen anion (Li) participates in the redox reaction, providing additional charge and discharge capacity. Therefore, within the operating voltage window (2.0-4.8 V), lithium-rich manganese cathode materials exhibit ultra-high discharge specific capacity (>250 mAh / g) and energy density (~1000 Wh / Kg), and the high manganese content also gives them a low-cost advantage. However, conventional lithium-rich manganese cathode materials are usually synthesized by high-temperature solid-state sintering, where oxygen ions are arranged in an ABCABC pattern in the layered structure, i.e., the O3 configuration. These lithium-rich manganese cathodes generally suffer from low initial charge and discharge efficiency, severe voltage decay, and poor rate performance, which are closely related to irreversible oxygen evolution, transition metal ion migration, and structural phase transitions. In contrast, the O2 configuration lithium-rich manganese cathode material prepared by low-temperature ion exchange has oxygen ions arranged in an ABCBA pattern in the layered structure. This structural arrangement allows for face-to-face contact between Li-O octahedra and Mn-O octahedra, inhibiting irreversible migration of transition metal ions into the lithium ion layer and resulting in a larger interlayer spacing between lithium ions. Therefore, O2-type lithium-rich manganese cathodes have significant advantages in suppressing irreversible oxygen precipitation, structural phase transitions, voltage decay, and improving the kinetics of lithium-rich manganese cathode materials.

[0004] Patent application number 201910988920.1 discloses a spinel-O2 type lithium-rich oxide cathode material, its preparation method, and its applications. A P2 type sodium cathode material is obtained by high-temperature calcination of a mixture of transition metal carbonate or transition metal hydroxide microsphere precursors and lithium and sodium salts. A spinel-modified O2 type lithium-rich manganese cathode is then successfully prepared using an ion exchange strategy between the lithium salt mixture and the P2 type sodium cathode material. The introduced spinel phase provides a three-dimensional lithium-ion channel and improves the voltage and capacity stability of the O2 type lithium-rich manganese cathode. However, the high-temperature treatment during ion exchange leads to structural instability of the O2 type lithium-rich manganese cathode material, and the introduction of the spinel phase also reduces the specific capacity of the cathode material. Patent application number 202210371412.0 discloses a method for synthesizing O2-type lithium-rich manganese-based cathode material with low voltage hysteresis. The O2-type lithium-rich manganese cathode material is synthesized by co-precipitation method and molten salt ion exchange method or solid-state sintering method and molten salt method. However, this method has the problem that the prepared O2-type lithium-rich manganese cathode has not undergone bulk structure doping modification treatment and is mostly a secondary agglomerate of primary particles. When applied to solid-state lithium batteries, it will have problems such as easy crushing of cathode particles, small primary particle size, poor bulk structure stability, poor solid-solid interface physical contact between O2-type lithium-rich manganese cathode and solid electrolyte, and serious interfacial side reactions. To stabilize the crystal structure of O2-type lithium-rich manganese cathodes and suppress interfacial side reactions, patent application number 202411228823.X discloses an O2-phase lithium-rich cathode material for lithium-ion batteries and its preparation method. By introducing Co into the O2-type lithium-rich manganese cathode, the reversible capacity and structural stability of the cathode material are improved. An Al2O3 coating layer is constructed on the cathode surface using a liquid-phase coating strategy, effectively suppressing interfacial side reactions. To reduce the manufacturing cost of O2-type lithium-rich manganese cathode materials and stabilize their crystal structure, patent application number 202410139009.4 discloses a titanium- or zirconium-doped cobalt-free and nickel-free O2-type lithium-rich oxide cathode material, its preparation method, and its applications. Titanium doping significantly improves the voltage and capacity stability of the cathode material, while zirconium doping enhances the structural stability of the O2-type lithium-rich manganese cathode and suppresses cracking and breakage during charging and discharging. However, this patent also faces the problems of small primary particle size and easily broken secondary particle agglomerates. When applied to solid-state lithium batteries, it still suffers from poor physical contact between the cathode and solid electrolyte interface, severe solid-solid interface side reactions, and deterioration of the electrochemical performance of solid-state lithium batteries. Therefore, there is an urgent need to develop a structurally stable, micron-sized O2-type lithium-rich manganese-based composite cathode material and its preparation method that is simple to process, has low manufacturing cost, and can significantly improve the performance of inorganic solid-state lithium batteries. Summary of the Invention

[0005] The present invention aims to provide a micron-sized O2-type lithium-rich manganese cathode material with synergistic modification (bulk doping and surface modification), its preparation and application in solid-state lithium batteries.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A synergistically modified micron-sized O2-type lithium-rich manganese cathode material is disclosed. This synergistically modified micron-sized O2-type lithium-rich manganese cathode material is an O2-type lithium-rich manganese cathode active material that has undergone bulk internal doping and external surface modification. The molecular formula of the O2-type lithium-rich manganese cathode active material is Li1(Li x Mn a TM y O2, wherein 0 < x ≤ 0.25, 0.3 ≤ a ≤ 0.7, 0.1 < y ≤ 0.6, and TM is a transition element of Ni and / or Co; the bulk doping element is one or more of Al, Ti or Zr; the external modification is the surface modification of the active material by means of a sulfur source or a fluorine source.

[0007] The synergistically modified micron-sized O2-type lithium-rich manganese cathode material is a primary particle of micron-sized O2-type lithium-rich manganese cathode material with a particle size of 0.5-5 μm.

[0008] A method for preparing the aforementioned synergistically modified micron-sized O2-type lithium-rich manganese cathode material. 1) Based on the molecular formula of O2-type lithium-rich manganese cathode active material, the transition metal salt, the salt solution corresponding to the bulk doping element, the precipitant and the coordination agent are mixed, and the hydroxide precursor powder of O2-type lithium-rich manganese cathode active material with uniform doping modification in the bulk phase is prepared by co-precipitation method. 2) The hydroxide precursor powder for obtaining O2-type lithium-rich manganese positive electrode active material was mixed with sodium salt, lithium salt and flux by ball milling. The mixture was fused and grown in a high-temperature molten salt environment to obtain micron-sized P2-type lithium-rich manganese sodium electrode layered oxide doped in the bulk phase. 3) The above-obtained P2-type lithium-rich manganese sodium layered oxide and lithium salt mixture are subjected to ion exchange reaction in a low-temperature, molten salt environment to obtain a micron-sized O2-type lithium-rich manganese cathode material uniformly doped in the bulk phase. 4) The O2-type lithium-rich manganese cathode material obtained above is subjected to low-temperature heating treatment under vacuum conditions with a sulfur source or a fluorine source to obtain a micron-sized O2-type lithium-rich manganese cathode material with uniform doping in the bulk phase and surface modification.

[0009] In step 1), based on the molecular formula of the O2-type lithium-rich manganese cathode active material, salt solutions of transition metal elements and bulk dopant elements with a molar concentration of 0.5-3 mol / L, a precipitant with a molar concentration of 2-5 mol / L, and a ligand with a molar concentration of 0.5-6 mol / L are sequentially pumped into a nitrogen-filled reactor at flow rates of 0.1-5 ml / min, 0.2-6 ml / min, and 0.1-3 ml / min, respectively. The reaction is carried out continuously for 15-48 h under conditions of stirring speed of 500-1000 rpm, reaction temperature of 40-60 ℃, and reaction pH of 10.5-11.5. Then, the reaction is allowed to proceed for 10-24 hours under conditions of stirring speed of 300-800 rpm, reaction temperature of 40-60 ℃, and reaction pH of 10.5-11.5. The aging process involves aging the material with h followed by vacuum drying to obtain the hydroxide precursor powder of the O2-type lithium-rich manganese cathode active material; wherein the transition metal is Ni and / or Co transition elements, and the bulk dopant is one or more of Al, Ti, and Zr.

[0010] The transition metal salt is one or more of sulfate, nitrate, and chloride.

[0011] The precipitant is sodium hydroxide solution, and the complexing agent is ammonia solution.

[0012] In step 2), the hydroxide precursor powder of the O2-type lithium-rich manganese positive electrode active material is mixed with sodium salt, lithium salt, and flux. The mixture is ball-milled in a molar ratio of 1:0.3-0.8:0.01-0.1:0.2-1.5. The flux is sodium chloride.

[0013] In step 2), a molten salt environment is provided by the flux molten salt sodium chloride. Lithium carbonate and sodium carbonate provide the lithium and sodium ions required to obtain micron-sized P2-type lithium-rich manganese sodium electroplated oxide. The temperature is increased to 450 °C at a rate of 5 °C / min in air and maintained for 4 h, then increased to 810 °C and maintained for 15 h, and then cooled to room temperature calcination conditions at a rate of 2 °C / min. This process achieves the fusion and growth of nanoparticles and the control of particle size in the P2-type lithium-rich manganese sodium electroplated oxide.

[0014] In step 3), the mixture of micron-sized P2-type lithium-rich manganese sodium oxide and lithium salt undergoes an ion exchange reaction in a low-temperature, molten salt environment (the low-temperature molten salt environment is the exchange reaction of lithium ions and sodium ions carried out at a heating rate of 5 °C / min in air atmosphere for 4 h, followed by natural cooling to room temperature) to obtain a micron-sized O2-type lithium-rich manganese cathode material uniformly doped in the bulk phase. The lithium salt mixture and the micron-sized P2-type lithium-rich manganese sodium-ion layered oxide are mixed in a ratio of Li ions in the lithium salt mixture to Na ions in the micron-sized P2-type lithium-rich manganese sodium-ion layered oxide with a molar ratio greater than 10:1 to obtain a mixture system; the lithium salt mixture is a mixture of lithium nitrate and lithium chloride with a molar ratio of 88:12, and the molten salt environment is a molten salt environment provided by the mixture of lithium nitrate and lithium chloride at low temperature.

[0015] In step 4), micron-sized O2-type lithium-rich manganese cathode material with bulk structure doped and surface modified is obtained by low-temperature heating treatment under vacuum conditions with a sulfur source or a fluorine source (heating to 150-300 ℃ at a heating rate of 2-8 ℃ / min and maintaining for 5-10 h); the surface modified sulfur source or fluorine source accounts for 0.01%-3% of the molar fraction of the micron-sized single crystal O2-type lithium-rich manganese cathode active material.

[0016] The sulfur source is one or more of elemental sulfur, disulfide, trisulfide, tetrasulfide, pentasulfide, hexasulfide, and octasulfide. The fluorine source is one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorooxalate borate, lithium bis(trifluoromethanesulfonyl)imide, lithium fluoride, and ammonium fluoride.

[0017] Application of the aforementioned synergistically modified micron-sized O2-type lithium-rich manganese cathode material, and application of the micron-sized O2-type lithium-rich manganese cathode active material in the preparation of cathode materials.

[0018] A cathode material comprising the aforementioned synergistically modified micron-sized O2-type lithium-rich manganese cathode material.

[0019] The cathode material is obtained by mixing micron-sized O2-type lithium-rich manganese cathode active material, inorganic solid electrolyte, and conductive agent in a mass ratio of 40-80:60-20:1-10 to obtain a micron-sized O2-type lithium-rich manganese-based composite cathode material for inorganic solid lithium batteries.

[0020] The conductive carbon is one or more of conductive carbon black (SP), acetylene black (AB), carbon nanotubes, vapor-grown carbon fiber (VGCF), and graphene.

[0021] The inorganic solid electrolyte is Li6PS5Cl, Li 5.5 PS5Cl 1.5 Li3PS4, Li6PS5Br, Li 10 GeP2S 12 One or more of LiInCl4, Li3YCl6, and Li3InCl6.

[0022] A method for preparing a cathode material involves dry ball milling and mixing a synergistically modified micron-sized O2-type lithium-rich manganese cathode material, an inorganic solid electrolyte, and a conductive agent in a mass ratio, as described above, to achieve sufficient contact and dispersion among the components, thereby obtaining a micron-sized O2-type lithium-rich manganese-based composite cathode material for inorganic solid-state lithium batteries.

[0023] The ball mill is used for dry ball milling, with a speed of 150-500 rpm and a milling time of 1-10 hours.

[0024] In summary, the preparation method of this invention can control the bulk phase, surface structure, morphology, and particle size of O2-type lithium-rich manganese cathode materials, achieving the preparation of structurally stable micron-sized O2-type lithium-rich manganese cathode materials. This enhances the solid-solid interface contact between the cathode active material and the inorganic solid electrolyte, suppresses interfacial side reactions, and promotes rapid lithium-ion transport at the interface, thus contributing to improved electrochemical performance of inorganic solid-state lithium batteries. Furthermore, this preparation method is simple, environmentally friendly, and allows for the recycling of molten salt reagents, facilitating the mass production of high-performance O2-type lithium-rich manganese composite cathode materials. Moreover, this invention is simple, low-cost, and applicable to the preparation of micron-sized O2-type lithium-rich manganese composite cathode materials for inorganic solid-state lithium batteries, achieving structurally stable, micron-sized O2-type lithium-rich manganese cathode materials. This promotes sufficient solid-solid interface contact and good interfacial lithium-ion transport between the O2-type lithium-rich manganese cathode and the inorganic solid electrolyte, suppresses interfacial chemical side reactions between the cathode active material and the inorganic solid electrolyte, and improves the electrochemical performance of inorganic solid-state lithium batteries.

[0025] An application of the cathode material, specifically its use in the preparation of an inorganic solid-state electrolyte all-solid-state battery.

[0026] An all-solid-state battery with an inorganic solid electrolyte, comprising the aforementioned composite cathode material.

[0027] The negative electrode of the inorganic solid electrolyte all-solid-state battery is one or more of the following: lithium metal negative electrode, lithium-indium negative electrode, carbon negative electrode, silicon negative electrode, and silicon-carbon negative electrode.

[0028] A method for preparing an inorganic solid electrolyte all-solid-state battery involves first placing inorganic solid electrolyte powder material in a solid-state battery mold and applying pressure to form a solid electrolyte layer; then placing the composite positive electrode material obtained above from one side of the positive electrode into the inorganic solid electrolyte layer and applying pressure; finally placing the negative electrode material on the other side of the inorganic solid electrolyte layer and applying pressure; and finally completing the preparation of the inorganic solid electrolyte all-solid-state battery using a sealing ring and a pressure mechanical clamp.

[0029] Advantages of this invention This invention employs a strategy of synergistic regulation of internal and external structures to obtain micron-sized O2-type lithium-rich manganese cathode materials with uniform internal doping and external modification. These materials are obtained through a co-precipitation method combined with low-temperature molten salt, which endows them with high crystal structure stability under operating voltage. This preparation method can regulate the surface structure and morphology of the micron-sized O2-type lithium-rich manganese cathode material, achieving good solid-solid interface contact between the micron-sized O2-type lithium-rich manganese cathode material and the inorganic solid electrolyte, suppressing interfacial chemical side reactions between the cathode active material and the inorganic solid electrolyte, promoting rapid lithium-ion transport at the interface, and contributing to improved electrochemical performance of inorganic solid-state lithium batteries. Furthermore, this preparation method is simple, environmentally friendly, and allows for the recycling of various molten salt reagents, facilitating the mass production of high-performance O2-type lithium-rich manganese composite cathode materials.

[0030] Compared with the prior art, the present invention has a simple process, low manufacturing cost, and is applicable to inorganic solid-state lithium batteries. Furthermore, compared with the single doping modification or surface modification techniques described in the prior art, the present invention adopts a strategy of synergistic regulation of internal and external structures. By uniformly doping elements within the bulk phase of the O2-type lithium-rich manganese cathode material, micron-sized particles are obtained, endowing the cathode active material with high intrinsic structural stability. Moreover, the micron-sized particles facilitate good dispersion between particles and complete exposure of the surface of individual particles, promoting sulfidation or fluorination treatment on the particle surface. This enhances the chemical stability between the cathode active material and the inorganic solid electrolyte, suppresses interfacial side reactions, and promotes rapid lithium-ion transport at the interface. By performing sulfidation or fluorination treatment on the surface of the O2-type lithium-rich manganese cathode material, while suppressing chemical side reactions between the cathode active material and the inorganic solid electrolyte and improving interfacial stability, the surface crystal structure of the cathode active material can also be stabilized, and the structural transformation from the surface to the bulk phase of the cathode active material—from layered to spinel to rock salt—can be prevented. The synergistic regulation of these two factors not only enhances the internal and external structural stability of the O2-type lithium-rich manganese cathode material under operating voltage, but also blocks the strong interaction and positive feedback between the bulk structure instability and the deterioration of the surface and interface structure of the cathode material. To achieve the synergistic effect, this invention utilizes the low-temperature melting environment provided by the flux to achieve the one-time preparation of well-dispersed micron-sized O2-type lithium-rich manganese cathode material particles. The micron-sized single-particle cathode not only avoids the particle breakage and pulverization problems of conventional O2-type lithium-rich manganese cathode materials in inorganic solid-state lithium batteries, but also achieves good physical contact between the cathode active material and the inorganic solid-state electrolyte interface. In addition, the micron-sized single-particle cathode material design strategy also improves the tap density of the O2-type lithium-rich manganese cathode material and helps to improve the volumetric energy density of inorganic solid-state lithium batteries. This invention significantly improves the electrochemical performance of O2-type lithium-rich manganese composite cathode materials in inorganic solid-state lithium batteries. Finally, in the preparation stage of P2-type lithium-rich manganese sodium-ion layered oxides, the addition of conventional flux sodium chloride helps lower the sintering temperature of the P2-type lithium-rich manganese sodium-ion layered oxides, promotes the full mixing and uniform dispersion of lithium and sodium ions required during the preparation of P2-type lithium-rich manganese sodium-ion layered oxides, compensates for sodium ion volatilization losses, and facilitates the fusion and growth of nanoparticles in P2-type lithium-rich manganese sodium-ion layered oxides at low calcination temperatures, as well as the preparation of micron-sized P2-type lithium-rich manganese sodium-ion layered oxides. Furthermore, it provides a basis for surface property regulation during subsequent surface modification of cathode active materials, ensuring good particle dispersion and complete exposure and full utilization of individual particle surfaces.

[0031] The preparation method of this invention helps to stabilize the internal and external crystal structure of O2-type lithium-rich manganese cathode material, suppress interfacial side reactions between cathode active material and inorganic solid electrolyte, achieve good interfacial contact between cathode active material and inorganic solid electrolyte, promote lithium-ion interfacial transport, suppress interfacial chemical side reactions between cathode active material and solid electrolyte, and help improve the electrochemical performance of inorganic solid lithium battery. Attached Figure Description

[0032] Figure 1 The image shows a SEM image of the synergistically modified micron-sized O2-type lithium-rich manganese cathode material prepared in Example 1.

[0033] Figure 2 SEM image of the conventional O2-type lithium-rich manganese cathode material prepared for Comparative Example 1.

[0034] Figure 3 SEM image of the synergistically modified micron-sized O3-type lithium-rich manganese cathode material prepared in Comparative Example 4.

[0035] Figure 4 Initial charge-discharge curves of the synergistically modified micron-sized O2-type lithium-rich manganese cathode material prepared in Example 1 in an inorganic sulfide solid-state lithium battery.

[0036] Figure 5 Initial charge-discharge curves of the synergistically modified micron-sized O3-type lithium-rich manganese cathode prepared in Comparative Example 4 in an inorganic sulfide solid-state lithium battery. Detailed Implementation

[0037] The following examples further illustrate specific embodiments of the present invention. It should be noted that the specific embodiments described herein are merely for illustration and explanation and are not intended to limit the scope of the present invention.

[0038] This invention utilizes a co-precipitation method combined with a low-temperature molten salt method to obtain micron-sized O2-type lithium-rich manganese cathode materials with stable bulk structure and synergistic surface modification. Specifically, in the preparation stage of the cathode active material precursor, the uniform introduction of doping elements into the bulk phase helps stabilize the crystal structure of the O2-type lithium-rich manganese cathode material. In the preparation stage of the cathode active material intermediate product, namely P2-type sodium-ion layered oxide powder, the fusion and growth of nano-sized primary grains in a high-temperature molten salt environment is utilized to achieve micron-sized particle growth control, which helps to achieve good solid-solid interface contact between the cathode active material and the inorganic solid electrolyte, inhibit the breakage of cathode active material particles, and improve the volumetric energy density of inorganic solid-state lithium batteries. Based on obtaining micron-sized O2-type lithium-rich manganese cathode materials with uniform doping in the bulk phase, the volatilization characteristics of sulfur or fluorine sources are used to achieve sulfidation or fluorination modification of the surface of the micron-sized O2-type lithium-rich manganese cathode materials with uniform doping in the bulk phase, which helps to reduce interfacial side reactions between cathode active material particles and inorganic solid electrolytes and promotes interfacial transport of lithium ions. This preparation method enables the control of the bulk phase, surface structure, morphology, and particle size of O2-type lithium-rich manganese cathode materials, achieving the preparation of structurally stable micron-sized O2-type lithium-rich manganese cathode materials. This enhances the solid-solid interface physical contact between the cathode active material and the solid electrolyte, suppresses interfacial side reactions, promotes lithium-ion interfacial transport, and improves the electrochemical performance of inorganic solid-state lithium batteries. Therefore, micron-sized O2-type lithium-rich manganese composite cathode materials with regulated internal and external structures exhibit superior electrochemical performance advantages in inorganic solid-state lithium batteries.

[0039] Example 1 Inorganic solid-state lithium battery composite cathode material is a micron-sized O2-type lithium-rich manganese cathode active material (Li1(Li)) with internal and external structure regulated. 0.1 Mn 0.62 Ni 0.23 Al 0.05 It is prepared by uniformly mixing O2, sulfide electrolyte (Li6PS5Cl) and conductive agent (VGCF). Among them, the positive electrode active material Li1 (Li 0.1 Mn 0.62 Ni 0.23 Al 0.05 The mass ratio of O2, Li6PS5Cl sulfide electrolyte, and conductive agent VGCF is 60:40:3.

[0040] Micron-sized O2-type lithium-rich manganese cathode active material Li1 (Li) with internal and external structure regulated in composite cathode materials for inorganic solid-state lithium batteries 0.1 Mn 0.62 Ni 0.23 Al 0.05 The specific steps for preparing O2 are as follows: Step 1: According to the O2-type lithium-rich manganese cathode active material Li1 (Li0.1 Mn 0.62 Ni 0.23 Al 0.05 O2 molecular formula, accurately weigh manganese sulfate, nickel sulfate and aluminum sulfate in a molar ratio of 0.62:0.23:0.05, then dissolve them in deionized water to prepare a 2 mol / L sulfate solution containing transition metals and doped elements; according to Mn 0.62 Ni 0.23 Al 0.075 The molecular formula of (OH)2 hydroxide precursor is given. Sodium hydroxide reagent is weighed and dissolved in deionized water to prepare a 4 mol / L sodium hydroxide precipitant. Concentrated ammonia solution with a mass fraction of 25 wt.% is weighed and a complexing agent of 1.5 mol / L is prepared, i.e., an ammonia solution.

[0041] Step 2: The sulfate solution, sodium hydroxide solution, and ammonia solution containing transition metals and dopants prepared above were sequentially pumped into a 5 L fully automated continuous reactor at flow rates of 1 ml / min, 1 ml / min, and 0.6 ml / min, respectively. The reactor was then subjected to a 24-hour aging process under constant conditions of nitrogen atmosphere, stirring speed of 800 rpm, reaction temperature of 50 ℃, and reaction pH of 11.2 to obtain a hydroxide precursor slurry of O2-type lithium-rich manganese cathode active material. Finally, after washing with deionized water, filtration, and vacuum drying at 80 ℃ for 24 hours, the hydroxide precursor powder Mn of O2-type lithium-rich manganese cathode active material was obtained. 0.62 Ni 0.23 Al 0.075 (OH)2.

[0042] Step 3: Based on the P2 type lithium-rich manganese sodium electrochemical layered oxide Na1(Li 0.1 Mn 0.62 Ni 0.23 Al 0.05 The molecular formula of O2, according to Mn 0.62 Ni 0.23 Al 0.075 The hydroxide precursor, sodium carbonate, lithium carbonate, and sodium chloride were accurately weighed and ball-milled to a molar ratio of (OH)2:Na2CO3:Li2CO3:NaCl of 1:0.5:0.05:0.5. The resulting mixture was then transferred to a muffle furnace and heated to 450 °C at a rate of 5 °C / min under air atmosphere, held for 4 h, then heated to 810 °C and held for 15 h, before being cooled to room temperature at a rate of 2 °C / min to obtain a micron-sized P2-type lithium-rich manganese sodium electrolayer oxide Na1(Li) with uniform Al doping in the bulk phase. 0.1 Mn 0.62 Ni 0.23 Al 0.05O2 (i.e., the hydroxide precursor, under the action of the molten salt eutectic agent, sodium chloride acts as a molten salt environment, while lithium carbonate and sodium carbonate provide the lithium and sodium ions required to obtain micron-sized P2-type lithium-rich manganese sodium electroplated oxides, realizing the fusion and growth of nanoscale primary grains of P2-type lithium-rich manganese sodium electroplated oxides in a high-temperature molten salt environment, thereby achieving the control of material particle size).

[0043] Step 4: Mix the lithium nitrate and lithium chloride mixture (molar ratio 88:12) with the above-mentioned micron-sized P2-type lithium-rich manganese sodium layered oxide at a molar ratio of 10:1 for Li ions to Na ions (provided in the micron-sized P2-type lithium-rich manganese sodium layered oxide) in an inert atmosphere (argon in this embodiment) for 1 h; place the uniformly mixed powder material in a muffle furnace and heat it to 290 ℃ at a heating rate of 5 ℃ / min in air atmosphere, then maintain the temperature for 4 h to carry out the exchange reaction of lithium ions and sodium ions, and then cool it naturally to room temperature; wash and filter the obtained powder material with water, and then dry it in a vacuum oven at 100 ℃ for 24 h to obtain a bulk structure doped and modified micron-sized O2-type lithium-rich manganese lithium battery cathode material.

[0044] Step 5: Elemental sulfur and the above-mentioned O2-type lithium-rich manganese cathode material were uniformly mixed at a molar ratio of 0.02:1 and vacuum-sealed using a high-temperature quartz tube. The temperature was increased to 200 °C at a heating rate of 5 °C / min and maintained for 8 h. The surface of the O2-type lithium-rich manganese cathode material was modified by the gas-solid interface reaction between sublimed sulfur and the cathode active material. Finally, micron-sized O2-type lithium-rich manganese cathode material with uniform aluminum doping in the bulk phase and surface sulfurization modification was obtained (see...). Figure 1 ).

[0045] Depend on Figure 1 It can be seen that the prepared O2-type lithium-rich manganese cathode material consists of monodisperse particles with a particle size of 0.3-3 μm, a narrow particle size distribution, and achieves fusion and growth between nanoscale primary particles.

[0046] A method for preparing micron-sized O2-type lithium-rich manganese composite cathode material suitable for inorganic solid-state lithium batteries: In an argon-filled glove box, 3 g of the obtained micron-sized O2-type lithium-rich manganese cathode material, 2 g of sulfide electrolyte Li6PS5Cl, and 0.15 g of conductive agent VGCF are placed in a ball mill jar, and 30 zirconium oxide grinding beads with a diameter of 10 mm are placed in it. The mixture is ball-milled at 200 rpm for 2 h in an argon atmosphere. The obtained composite cathode material is then manually ground in the glove box for 0.5 h to obtain a micron-sized O2-type lithium-rich manganese composite cathode material in which all components are fully mixed and in contact.

[0047] Inorganic solid electrolyte all-solid-state battery: Sulfide solid-state lithium batteries are assembled in an argon-filled glove box. The all-solid-state battery is assembled using a 10 mm diameter STC-SB polyether ether ketone (PEEK) finished product mold. First, 80 mg of Li6PS5Cl electrolyte powder was added to the PEEK inner cavity and cold-pressed and allowed to stand for 2 min at 150 MPa. Then, 10 mg of micron-sized O2-type lithium-rich manganese composite cathode material powder was evenly spread on one side of the Li6PS5Cl electrolyte layer and cold-pressed and allowed to stand for 2 min at 370 MPa. Finally, a lithium-indium alloy anode composed of indium foil (Φ=8 mm) and lithium foil (Φ=3 mm) was placed on the other side of the electrolyte layer and cold-pressed and allowed to stand for 1 min at 150 MPa. At this point, a sandwich structure of cathode-electrolyte-anode was formed inside the inorganic solid-state lithium battery. Foamed nickel and foamed copper current collectors were placed at the cathode and anode ends respectively to promote rapid electron transport. A stainless steel mechanical press was assembled outside the PEEK battery mold and an external pressure of 200 MPa was applied to ensure close contact between the components inside the inorganic solid-state lithium battery. The battery was then subjected to a test at 30 ℃ and 2.0-4.7 V (vs. Li + / Li), 0.1 C (1 C = 200 mA g) -1 Under the conditions of charging and discharging inorganic solid-state lithium batteries, (see) Figure 4 The sulfide solid-state lithium battery assembled in Example 1 achieved a first-cycle discharge capacity of 195.65 mAh g⁻¹. -1 The initial coulombic efficiency was 91.43%, and after 50 cycles, the discharge specific capacity of the inorganic solid-state lithium battery still reached 189.2 mAh g⁻¹. -1 The voltage drop was only 0.32 mV / cycle.

[0048] Example 2 Inorganic solid-state lithium battery composite cathode material is a micron-sized O2-type lithium-rich manganese cathode active material (Li1(Li)) with internal and external structure regulated. 0.1 Mn 0.66 Ni 0.13 Co 0.06 Zr 0.05 The electrode is prepared by uniformly mixing O2, sulfide electrolyte (Li6PS5Cl), and conductive agent VGCF. The positive electrode active material (Li1(Li 0.1 Mn 0.66 Ni 0.13 Co 0.06 Zr 0.05 The mass ratio of O2, sulfide electrolyte (Li6PS5Cl), and conductive agent VGCF is 60:40:3.

[0049] Micron-sized O2-type lithium-rich manganese cathode active material Li1 (Li) with internal and external structure regulated in composite cathode materials for inorganic solid-state lithium batteries 0.1 Mn 0.66 Ni 0.13 Co 0.06 Zr 0.05 The specific steps for preparing O2 are as follows: Step 1: According to the O2-type lithium-rich manganese cathode active material Li1 (Li 0.1 Mn 0.66 Ni 0.13 Co 0.06 Zr 0.05 O2 molecular formula, accurately weigh manganese sulfate, nickel sulfate, cobalt sulfate and zirconium sulfate in a molar ratio of 0.66: 0.13: 0.06: 0.05, then dissolve in deionized water to prepare a 2 mol / L transition metal sulfate solution; according to Mn 0.66 Ni 0.13 Co 0.06 Zr 0.05 The molecular formula of (OH)2 hydroxide precursor is given. Sodium hydroxide reagent is weighed and dissolved in deionized water to prepare a 4 mol / L sodium hydroxide precipitant. Concentrated ammonia solution with a mass fraction of 25 wt.% is weighed and a complexing agent of 1.5 mol / L is prepared, i.e., an ammonia solution.

[0050] Step 2: Transition metal salt solution, sodium hydroxide solution, and ammonia solution were sequentially pumped into a 5 L fully automated continuous reactor at flow rates of 2 ml / min, 2 ml / min, and 1.2 ml / min, respectively. The reactor was kept under constant conditions of nitrogen atmosphere, stirring speed of 800 rpm, reaction temperature of 50 ℃, and reaction pH of 11.5 for 24 h for aging treatment to obtain a hydroxide precursor slurry of O2-type lithium-rich manganese cathode active material. Finally, after washing with deionized water, filtration, and vacuum drying at 80 ℃ for 24 h, the hydroxide precursor powder of O2-type lithium-rich manganese cathode active material (Mn) was obtained. 0.66 Ni 0.18 Co 0.06 Zr 0.05 (OH)2.

[0051] Step 3: Based on the P2 type lithium-rich manganese sodium electrochemical layered oxide Na1(Li 0.1 Mn 0.66 Ni 0.13 Co 0.06 Zr 0.05 The molecular formula of O2, according to Mn 0.66 Ni 0.13 Co 0.06 Zr 0.05The above-obtained hydroxide precursor, sodium carbonate, lithium carbonate, and flux sodium chloride were accurately weighed and ball-milled to obtain a hydroxide precursor, sodium carbonate, lithium carbonate, and flux sodium chloride in a molar ratio of 1:0.5:0.05:0.5. The resulting mixture powder was transferred to a muffle furnace and heated to 450 °C at a rate of 5 °C / min under air atmosphere and held for 4 h. Then, the temperature was increased to 820 °C and held for 16 h, and then cooled to room temperature at a rate of 2 °C / min to obtain micron-sized P2-type lithium-rich manganese sodium electrolayered oxide Na1(Li 0.1 Mn 0.66 Ni 0.13 Co 0.06 Zr 0.05 )O2.

[0052] Step 4: Mix the lithium nitrate and lithium chloride mixture (molar ratio 88:12) with the above-mentioned micron-sized P2-type lithium-rich manganese sodium electrochemical layered oxide at a molar ratio of Li ions to Na ions (provided in the micron-sized P2-type lithium-rich manganese sodium electrochemical layered oxide) of 10:1 in an inert atmosphere for 1 h; place the uniformly mixed powder material in a muffle furnace and heat it to 290 ℃ at a heating rate of 5 ℃ / min in air atmosphere, and maintain it for 4 h to carry out the exchange reaction of lithium ions and sodium ions, and then cool it naturally to room temperature; wash the obtained powder material with water, filter it, and dry it in a vacuum oven at 100 ℃ for 24 h to obtain the bulk doped and modified micron-sized O2-type lithium-rich manganese cathode material.

[0053] Step 5: Ammonium fluoride and the above-mentioned micron-sized O2-type lithium-rich manganese cathode material are uniformly mixed at a molar ratio of 0.03:1 and vacuum sealed using a high-temperature quartz tube. The temperature is increased to 150 °C at a heating rate of 5 °C / min and maintained for 8 h. The surface of the micron-sized O2-type lithium-rich manganese cathode material is fluorinated and modified by the gas-solid interface reaction between ammonium fluoride and the cathode active material. The final micron-sized O2-type lithium-rich manganese cathode material is uniformly doped with zirconium element in the bulk phase and fluorinated and modified on the surface.

[0054] According to Example 1, a micron-sized O2-type lithium-rich manganese composite cathode material was prepared and a sulfide solid-state lithium battery was assembled: the obtained micron-sized O2-type lithium-rich manganese composite cathode, Li6PS5Cl sulfide electrolyte, and lithium-indium alloy anode were assembled into an inorganic sulfide solid-state lithium battery in an argon-filled glove box.

[0055] The sulfide solid-state battery assembled in Example 2 above was tested at 30 °C and 2.0-4.7 V (vs. Li). + / Li), 0.1 C (1 C = 200 mA g) -1Charge-discharge tests were conducted under the specified conditions. The sulfide solid-state lithium battery assembled in Example 2 achieved a first-cycle discharge capacity of 191.2 mAh g⁻¹. -1 The initial coulombic efficiency was 92.6%, and after 50 cycles, the discharge specific capacity of the solid-state lithium battery still reached 188.7 mAh g⁻¹. -1 The voltage drop was only 0.37 mV / cycle.

[0056] Example 3 Micron-sized O2-type lithium-rich manganese cathode material was prepared according to Example 1.

[0057] The composite cathode material for inorganic solid-state lithium batteries is a micron-sized O2-type lithium-rich manganese cathode material, Li 5.5 PS5Cl 1.5 Sulfide electrolytes and conductive agents VGCF, including micron-sized single-crystal O2-type lithium-rich manganese cathode materials and Li 5.5 PS5Cl 1.5 The mass ratio of sulfide electrolyte to conductive agent VGCF is 65:35:3.

[0058] Assemble a sulfide solid-state lithium battery as described in Example 1: Assemble a sulfide solid-state lithium battery in a glove box filled with argon gas using the obtained micron-sized O2-type lithium-rich manganese composite cathode, Li6PS5Cl sulfide electrolyte, and lithium-indium alloy anode.

[0059] The sulfide solid-state battery assembled in Example 3 above was tested at 30 °C and 2.0-4.7 V (vs. Li). + / Li), 0.1 C (1 C = 200 mA g) -1 Charge-discharge tests were conducted under the specified conditions. The sulfide solid-state lithium battery assembled in Example 3 achieved a first-cycle discharge capacity of 210.2 mAh g⁻¹. -1 The initial coulombic efficiency was 93.1%, and after 50 cycles, the discharge specific capacity of the solid-state lithium battery reached 186.6 mAh g⁻¹. -1 The voltage decay was 0.41 mV / cycle.

[0060] Example 4 Micron-sized O2-type lithium-rich manganese cathode material was prepared according to Example 1.

[0061] The composite cathode material for inorganic solid-state lithium batteries consists of micron-sized O2-type lithium-rich manganese cathode material, Li3InCl6 halide electrolyte, and conductive agent VGCF, wherein the mass ratio of micron-sized O2-type lithium-rich manganese cathode material, Li3InCl6 halide electrolyte, and conductive agent VGCF is 65:35:3.

[0062] Assemble a halide solid-state lithium battery as described in Example 1: Assemble a sulfide solid-state lithium battery in a glove box filled with argon gas using the obtained micron-sized O2-type lithium-rich manganese composite cathode, Li6PS5Cl sulfide electrolyte, and lithium-indium alloy anode.

[0063] The halide solid-state battery assembled in Example 4 above was tested at 30 °C and 2.0-4.7 V (vs. Li). + / Li), 0.1 C (1 C = 200 mA g) -1 Charge-discharge tests were conducted under the specified conditions. The sulfide solid-state lithium battery assembled in Example 4 achieved a first-cycle discharge capacity of 220.3 mAh g⁻¹. -1 The initial coulombic efficiency was 95.3%, and after 50 cycles, the discharge specific capacity of the solid-state lithium battery reached 191.3 mAh g⁻¹. -1 The voltage decay was 0.56 mV / cycle.

[0064] Comparative Example 1 Inorganic solid-state lithium battery composite cathode material consists of O2-type lithium-rich manganese cathode active material (Li1(Li 0.1 Mn 0.67 Ni 0.23 The electrode is prepared by uniformly mixing O2, sulfide electrolyte (Li6PS5Cl), and conductive agent VGCF. Among them, the positive electrode active material Li1 (Li 0.1 Mn 0.67 Ni 0.23 The mass ratio of O2, Li6PS5Cl sulfide electrolyte, and conductive agent VGCF is 60:40:3.

[0065] O2-type lithium-rich manganese cathode active material Li1 (Li) in composite cathode materials for inorganic solid-state lithium batteries 0.1 Mn 0.67 Ni 0.23 The specific steps for preparing O2 are as follows: Step 1: According to the O2-type lithium-rich manganese cathode active material Li1 (Li 0.1 Mn 0.67 Ni 0.23 O2 molecular formula, accurately weigh manganese sulfate and nickel sulfate in a molar ratio of 0.67:0.23, dissolve them in deionized water, and prepare a 2 mol / L transition metal sulfate solution; according to Mn 0.67 Ni 0.23 The molecular formula of (OH)2 hydroxide precursor is given. Sodium hydroxide reagent is weighed and dissolved in deionized water to prepare a 4 mol / L sodium hydroxide precipitant. Concentrated ammonia solution with a mass fraction of 25 wt.% is weighed and a complexing agent of 1.5 mol / L is prepared, i.e., an ammonia solution.

[0066] Step 2: The above-prepared transition metal salt solution, sodium hydroxide solution, and ammonia solution were sequentially pumped into a 5 L fully automated continuous reactor at flow rates of 1 ml / min, 1 ml / min, and 0.6 ml / min, respectively. The reactor was subjected to aging treatment under nitrogen atmosphere, stirring speed of 800 rpm, reaction temperature of 50 ℃, and reaction pH of 11.0 for 24 h. After aging treatment, the mixture was washed with deionized water, filtered, and vacuum dried at 80 ℃ for 24 h to obtain the hydroxide precursor Mn of the O2-type lithium-rich manganese cathode active material. 0.67 Ni 0.23 (OH)2.

[0067] Step 3: Based on the P2 type lithium-rich manganese sodium electrochemical layered oxide Na1(Li 0.1 Mn 0.67 Ni 0.23 The molecular formula of O2, according to Mn 0.67 Ni 0.23 Accurately weigh the hydroxide precursor, sodium carbonate, and lithium carbonate in a molar ratio of (OH)2:Na2CO3:Li2CO3 of 1:0.5:0.05 and mix them thoroughly. Transfer the resulting powder mixture to a muffle furnace and heat it to 450 °C at a rate of 5 °C / min under air atmosphere, then maintain the temperature for 4 h. Next, heat it to 810 °C and maintain the temperature for 15 h, then cool it to room temperature at a rate of 2 °C / min to obtain P2-type lithium-rich manganese sodium electrolayered oxide Na1(Li 0.1 Mn 0.67 Ni 0.23 )O2.

[0068] Step 4: A mixture of lithium nitrate and lithium chloride with a molar ratio of 88:12 was mixed with the above-mentioned micron-sized P2-type lithium-rich manganese sodium-ion layered oxide at a molar ratio of Li ions to Na ions (provided in the micron-sized P2-type lithium-rich manganese sodium-ion layered oxide) of 10:1 in an inert atmosphere for 1 h. The uniformly mixed powder material was placed in a muffle furnace and heated to 290 °C at a heating rate of 5 °C / min in air atmosphere and maintained for 4 h to carry out the exchange reaction of lithium ions and sodium ions. Then it was naturally cooled to room temperature. The obtained powder material was washed with water, filtered, and dried in a vacuum oven at 100 °C for 24 h to obtain O2-type lithium-rich manganese lithium battery cathode material (see Figure 2 ).

[0069] Depend on Figure 2 As can be seen, the O2-type lithium-rich manganese cathode material prepared in Comparative Example 1 has a particle size of 0.2-1 μm, a wide particle size distribution, and no fusion or growth between nanoparticles occurred.

[0070] According to Example 1, an O2-type lithium-rich manganese composite cathode material was prepared and an inorganic sulfide solid-state lithium battery was assembled. The obtained O2-type lithium-rich manganese composite cathode material, Li6PS5Cl sulfide electrolyte, and lithium-indium alloy anode were assembled into an inorganic sulfide solid-state lithium battery in an argon-filled glove box.

[0071] The sulfide solid-state battery assembled in Comparative Example 1 was tested at 30 °C and 2.0–4.7 V (vs. Li). + / Li), 0.1 C (1 C = 200 mA g) -1 Charge-discharge tests were conducted under the following conditions. The sulfide solid-state lithium battery assembled in Comparative Example 1 exhibited a first-cycle discharge capacity of 130.6 mAh g⁻¹. -1 The initial coulombic efficiency was 82.6%, and the discharge specific capacity of the solid-state lithium battery after 50 cycles was 121.9 mAh g. -1 The voltage decay was 0.38 mV / cycle.

[0072] As can be seen from the electrochemical data of Example 1 and Comparative Example 1, the micron-sized O2-type lithium-rich manganese cathode material with internal and external structure regulation obtained by Example 1 overcomes the shortcomings of previous technologies that only focused on single regulation strategies such as bulk structure or surface modification when preparing O2-type lithium-rich manganese cathodes, or the prepared O2-type lithium-rich manganese cathodes were polycrystalline but not suitable for inorganic solid-state lithium batteries. It can achieve bulk doping of the O2-type lithium-rich manganese cathode active material, stabilizing the crystal structure of the cathode active material; modifying the surface of the O2-type lithium-rich manganese cathode active material particles helps to improve the interfacial stability between the cathode active material and the inorganic solid-state electrolyte, suppress interfacial side reactions, and promote the interfacial transport of lithium ions; finally, the micron-sized O2-type lithium-rich manganese cathode particles help to increase the tap density of the cathode material, avoid the breakage and pulverization of the cathode active particles, achieve good contact between the cathode active material and the inorganic solid-state electrolyte, and reduce the interfacial side reactions between the newly exposed crystal faces of the cathode active material particles and the inorganic solid-state electrolyte due to breakage and pulverization. Therefore, the micron-sized O2-type lithium-rich manganese cathode material with internal and external structure regulation prepared in Example 1 has higher capacity contribution, coulombic efficiency and lower voltage decay in inorganic solid-state lithium batteries.

[0073] Comparative Example 2 Inorganic solid-state lithium battery composite cathode material is an O2-type lithium-rich manganese cathode active material (Li1(Li)) with internal and external structure regulated. 0.1 Mn 0.62 Ni 0.23 Al 0.05 It is prepared by uniformly mixing O2, sulfide electrolyte (Li6PS5Cl) and conductive agent VGCF. Among them, the positive electrode active material Li1 (Li 0.1 Mn 0.62 Ni0.23 Al 0.05 The mass ratio of O2, Li6PS5Cl sulfide electrolyte, and conductive agent VGCF is 60:40:3.

[0074] Li1 (Li2O2-type lithium-rich manganese cathode active material with internal and external structure regulated in composite cathode materials for inorganic solid-state lithium batteries) 0.1 Mn 0.62 Ni 0.23 Al 0.05 The specific steps for preparing O2 are as follows: Step 1: According to the O2-type lithium-rich manganese cathode active material Li1 (Li 0.1 Mn 0.62 Ni 0.23 Al 0.05 O2 molecular formula, accurately weigh manganese sulfate, nickel sulfate and aluminum sulfate in a molar ratio of 0.62:0.23:0.05, and dissolve them in deionized water to prepare a 2 mol / L sulfate solution containing transition metals and doped elements; according to Mn 0.62 Ni 0.23 Al 0.075 The molecular formula of (OH)2 hydroxide precursor is given. Sodium hydroxide reagent is weighed and dissolved in deionized water to prepare a 4 mol / L sodium hydroxide precipitant. Concentrated ammonia solution with a mass fraction of 25 wt.% is weighed and a complexing agent of 1.5 mol / L is prepared, i.e., an ammonia solution.

[0075] Step 2: The sulfate solution, sodium hydroxide solution, and ammonia solution containing transition metals and doped elements prepared above were sequentially pumped into a 5 L fully automated continuous reactor at flow rates of 1 ml / min, 1 ml / min, and 0.6 ml / min, respectively. The reactor was then subjected to a nitrogen atmosphere, a stirring speed of 800 rpm, a reaction temperature of 50 ℃, and a reaction pH of 11.2 for 24 hours for aging treatment. After aging, the reactor was washed with deionized water, filtered, and vacuum dried at 80 ℃ for 24 hours to obtain the hydroxide precursor Mn of the O2-type lithium-rich manganese cathode active material. 0.62 Ni 0.23 Al 0.075 (OH)2.

[0076] Step 3: Based on the P2 type lithium-rich manganese sodium electrochemical layered oxide Na1(Li 0.1 Mn 0.62 Ni 0.23 Al 0.05 The molecular formula of O2, according to Mn 0.62 Ni 0.23 Al 0.075Accurately weigh the hydroxide precursor, sodium carbonate, and lithium carbonate in a molar ratio of (OH)2:Na2CO3:Li2CO3 of 1:0.5:0.05 and mix them thoroughly. Transfer the resulting powder mixture to a muffle furnace and heat it to 450 °C at a rate of 5 °C / min under air atmosphere, then maintain the temperature for 4 h. Next, heat it to 810 °C and maintain the temperature for 15 h, then cool it to room temperature at a rate of 2 °C / min to obtain P2-type lithium-rich manganese sodium electrolayered oxide Na1(Li 0.1 Mn 0.62 Ni 0.23 Al 0.05 )O2.

[0077] Step 4: Mix the lithium nitrate and lithium chloride mixture (88:12 molar ratio) with the above-mentioned micron-sized P2-type lithium-rich manganese sodium electrochemical layered oxide at a molar ratio of Li ions to Na ions (provided in the micron-sized P2-type lithium-rich manganese sodium electrochemical layered oxide) in an inert atmosphere for 1 h; place the uniformly mixed powder material in a muffle furnace and heat it to 290 ℃ at a heating rate of 5 ℃ / min in air atmosphere, then maintain the temperature for 4 h to carry out the exchange reaction of lithium ions and sodium ions, and then cool it naturally to room temperature; wash and filter the obtained powder material with water, and then dry it in a vacuum oven at 100 ℃ for 24 h to obtain the bulk doped modified O2-type lithium-rich manganese cathode material.

[0078] Step 5: Elemental sulfur and the above-mentioned O2-type lithium-rich manganese cathode material are uniformly mixed at a molar ratio of 0.02:1 and vacuum sealed using a high-temperature quartz tube. The temperature is increased to 200 ℃ at a heating rate of 5 ℃ / min and maintained for 8 h. The surface of the O2-type lithium-rich manganese cathode material is modified by the gas-solid interface reaction between sublimed sulfur and the cathode active material, and finally, an O2-type lithium-rich manganese cathode material with uniform aluminum doping in the bulk phase and surface sulfide modification is obtained.

[0079] Assemble an inorganic sulfide solid-state lithium battery as described in Example 1: Assemble an inorganic sulfide solid-state lithium battery in a glove box filled with argon gas by using the above-mentioned O2-type lithium-rich manganese composite cathode material with internal and external structure regulation, Li6PS5Cl sulfide electrolyte, and lithium-indium alloy anode.

[0080] The sulfide solid-state battery assembled in Comparative Example 2 was tested at 30 °C and 2.0–4.7 V (vs. Li). + / Li), 0.1 C (1 C = 200 mA g) -1 Charge-discharge tests were conducted under the following conditions. The sulfide solid-state lithium battery assembled in Comparative Example 2 achieved a first-cycle discharge capacity of 145.5 mAh g⁻¹. -1The initial coulombic efficiency was 88.2%, and the discharge specific capacity of the solid-state lithium battery after 50 cycles was 132.6 mAh g. -1 The voltage decay was 0.36 mV / cycle.

[0081] Comparative Example 3 Inorganic solid-state lithium battery composite cathode material consists of micron-sized O2-type lithium-rich manganese cathode active material (Li1(Li 0.1 Mn 0.67 Ni 0.23 It is prepared by uniformly mixing O2, sulfide electrolyte (Li6PS5Cl) and conductive agent VGCF. Among them, the positive electrode active material Li1 (Li 0.1 Mn 0.67 Ni 0.23 The mass ratio of O2, Li6PS5Cl sulfide electrolyte, and conductive agent VGCF is 60:40:3.

[0082] Micron-sized O2-type lithium-rich manganese cathode active material Li1 (Li) for inorganic solid-state lithium batteries 0.1 Mn 0.67 Ni 0.23 The preparation method of O2, specifically the following steps: Step 1: According to the O2-type lithium-rich manganese cathode active material Li1 (Li 0.1 Mn 0.67 Ni 0.23 O2 molecular formula, accurately weigh manganese sulfate and nickel sulfate in a molar ratio of 0.67:0.23, and then dissolve them together in deionized water to prepare a 2 mol / L transition metal salt solution; according to Mn 0.67 Ni 0.23 The molecular formula of the (OH)₂ hydroxide precursor is given. Sodium hydroxide reagent with a molar excess of 1.2 is weighed and dissolved in deionized water to prepare a 4 mol / L sodium hydroxide precipitant. Concentrated ammonia solution with a mass fraction of 25 wt% is weighed and a 1.5 mol / L complexing agent, i.e., an ammonia solution, is prepared.

[0083] Step 2: Transition metal salt solution, sodium hydroxide solution, and ammonia solution were sequentially pumped into a 5 L fully automated continuous reactor at flow rates of 1 ml / min, 1 ml / min, and 0.6 ml / min, respectively. The reactor was then subjected to a nitrogen atmosphere, a stirring speed of 800 rpm, a reaction temperature of 50 ℃, and a reaction pH of 11.0 for 24 h for aging treatment. After aging, the mixture was washed with deionized water, filtered, and vacuum dried at 80 ℃ for 24 h to obtain the hydroxide precursor Mn of the O2-type lithium-rich manganese cathode active material. 0.67 Ni 0.23 (OH)2.

[0084] Step 3: Based on the P2 type lithium-rich manganese sodium electrochemical layered oxide Na1(Li 0.1 Mn 0.7 Ni 0.23 The molecular formula of O2, according to Mn 0.67 Ni 0.23 Accurately weigh out the hydroxide precursor, sodium carbonate, lithium carbonate, and sodium chloride in a molar ratio of (OH)2:Na2CO3:Li2CO3:NaCl of 1:0.5:0.05:0.5 and mix them thoroughly. Transfer the resulting powder mixture to a muffle furnace and heat it to 450 °C at a rate of 5 °C / min under air atmosphere, then maintain the temperature for 4 h. Next, heat it to 830 °C and maintain the temperature for 15 h, then cool it to room temperature at a rate of 2 °C / min to obtain micron-sized P2-type lithium-rich manganese sodium electrolayered oxide Na1(Li 0.1 Mn 0.67 Ni 0.23 )O2.

[0085] Step 4: Mix the lithium nitrate and lithium chloride mixture (88:12 molar ratio) with the above-mentioned micron-sized P2-type lithium-rich manganese sodium electrochemical layered oxide at a molar ratio of Li ions to Na ions (provided in the micron-sized P2-type lithium-rich manganese sodium electrochemical layered oxide) of 10:1 in an inert atmosphere for 1 h; place the uniformly mixed powder material in a muffle furnace and heat it to 290 ℃ at a heating rate of 5 ℃ / min in air atmosphere, and maintain it for 4 h to carry out the exchange reaction of lithium ions and sodium ions, and then cool it naturally to room temperature; wash the obtained powder material with water, filter it, and dry it in a vacuum oven at 100 ℃ for 24 h to obtain micron-sized O2-type lithium-rich manganese cathode material.

[0086] Assemble an inorganic sulfide solid-state lithium battery as described in Example 1: Assemble the above-mentioned micron-sized O2-type lithium-rich manganese composite cathode material, Li6PS5Cl sulfide electrolyte, and lithium-indium alloy anode in an argon-filled glove box.

[0087] The sulfide solid-state battery assembled in Comparative Example 3 was tested at 30 °C and 2.0–4.7 V (vs. Li). + / Li), 0.1 C (1C = 200 mA g) -1 Under the specified conditions, charge-discharge tests were conducted. The inorganic sulfide solid-state lithium battery assembled in Comparative Example 3 exhibited a first-cycle discharge capacity of 153.1 mAh g⁻¹. -1 The initial coulombic efficiency was 87.1%, and after 50 cycles, the discharge specific capacity of the solid-state lithium battery was 133.6 mAhg. -1 The voltage decay was 0.41 mV / cycle.

[0088] Comparative Example 4 Inorganic solid-state lithium battery composite cathode material is a micron-sized O3-type lithium-rich manganese cathode active material (Li1(Li)) with internal and external structure regulated. 0.2 Mn 0.62 Ni 0.23 Al 0.05 It is prepared by uniformly mixing O2, sulfide electrolyte (Li6PS5Cl) and conductive agent VGCF. Among them, the positive electrode active material Li1 (Li 0.2 Mn 0.62 Ni 0.23 Al 0.05 The mass ratio of O2, Li6PS5Cl sulfide electrolyte, and conductive agent VGCF is 60:40:3.

[0089] Micron-sized O3-type lithium-rich manganese cathode active material Li1 (Li) with internal and external structure regulated in composite cathode materials for inorganic solid-state lithium batteries 0.2 Mn 0.62 Ni 0.23 Al 0.05 The preparation method of O2, specifically the following steps: Step 1: According to the O3-type lithium-rich manganese cathode active material Li1 (Li 0.2 Mn 0.62 Ni 0.23 Al 0.05 O2 molecular formula, accurately weigh manganese sulfate, nickel sulfate and aluminum sulfate in a molar ratio of 0.62:0.23:0.05, and dissolve them in deionized water to prepare a 2 mol / L sulfate solution containing transition metals and doped elements; according to Mn 0.62 Ni 0.23 Al 0.075 The molecular formula of (OH)2 hydroxide precursor is given. Sodium hydroxide reagent is weighed and dissolved in deionized water to prepare a 4 mol / L sodium hydroxide precipitant. Concentrated ammonia solution with a mass fraction of 25 wt.% is weighed and a complexing agent of 1.5 mol / L is prepared, i.e., an ammonia solution.

[0090] Step 2: Sulfate solution containing transition metals and dopants, sodium hydroxide solution, and ammonia solution were sequentially pumped into a 5 L fully automated continuous reactor at flow rates of 1 ml / min, 1 ml / min, and 0.6 ml / min, respectively. The reactor was subjected to a nitrogen atmosphere, a stirring speed of 800 rpm, a reaction temperature of 50 ℃, and a reaction pH of 11.2 for 24 h for aging treatment. After aging, the mixture was washed with deionized water, filtered, and vacuum dried at 80 ℃ for 24 h to obtain the hydroxide precursor Mn of the O3-type lithium-rich manganese cathode active material. 0.62 Ni 0.23 Al 0.075 (OH)2.

[0091] Step 3: According to Mn 0.62 Ni 0.23 Al 0.075 The molar ratio of (OH)2:LiOH.H2O was 1:1.3. The hydroxide precursor and lithium hydroxide monohydrate were accurately weighed and mixed thoroughly. The resulting powder mixture was transferred to a muffle furnace and heated to 450 °C at a rate of 5 °C / min under air atmosphere, then maintained for 4 h. The temperature was then increased to 850 °C and maintained for 15 h, followed by cooling to room temperature at a rate of 2 °C / min to obtain micron-sized O3-type lithium-rich manganese layered oxide Li1(Li 0.2 Mn 0.62 Ni 0.23 Al 0.05 O2 (see) Figure 3 ).

[0092] Depend on Figure 3 It can be seen that the O3-type lithium-rich manganese cathode material prepared in Comparative Example 4 has a particle size of 0.3-1 μm.

[0093] Step 5: Elemental sulfur and the above-mentioned O3-type lithium-rich manganese cathode material are uniformly mixed at a molar ratio of 0.02:1 and vacuum sealed using a high-temperature quartz tube. The temperature is increased to 200 ℃ at a heating rate of 5 ℃ / min and maintained for 8 h. The surface of the O3-type lithium-rich manganese cathode material is modified by the gas-solid interface reaction between sublimed sulfur and the cathode active material, and finally, the O3-type lithium-rich manganese cathode material with uniform doping in the bulk phase and surface modification by sulfurization is obtained.

[0094] Assemble a sulfide solid-state lithium battery as described in Example 1: Assemble a sulfide solid-state lithium battery in a glove box filled with argon gas using the obtained micron-sized O3-type lithium-rich manganese composite cathode material, Li6PS5Cl sulfide electrolyte, and lithium-indium alloy anode.

[0095] The inorganic sulfide solid-state batteries assembled in Comparative Example 4 were tested at 30 °C and 2.0–4.7 V (vs. Li). + / Li), 0.1C (1 C = 200 mA g) -1 Charge and discharge tests were performed under the following conditions (see...). Figure 5 The inorganic sulfide solid-state lithium battery assembled in Comparative Example 4 had a first-cycle discharge capacity of 186.7 mAh g⁻¹. -1 The initial coulombic efficiency was 76.2%, and the discharge specific capacity of the solid-state lithium battery after 50 cycles was 165.3 mAh g. -1 The voltage decay was 0.82 mV / cycle.

[0096] Table 1 compares the composition and electrochemical performance of the composite cathode materials in the above embodiments and comparative examples.

[0097] Table 1. Comparison of composite cathode composition and electrochemical performance between each embodiment and the comparative example.

[0098] In summary, compared with Comparative Examples 1-3, the cathode materials of the embodiments of the present invention, in the stage of preparing O2-type lithium-rich manganese cathode material precursor, achieve bulk internal doping modification of the cathode active material, which helps to stabilize the crystal structure of the O2-type lithium-rich manganese cathode material, inhibit the degradation of the crystal structure of the cathode material during charge and discharge, thereby improving its electrochemical performance such as charge and discharge capacity and cycle stability; in the stage of preparing P2-type lithium-rich manganese sodium electrolayered oxide, by introducing a third component, namely the low-melting-point flux sodium chloride, it helps to lower the sintering temperature of the P2-type lithium-rich manganese sodium electrolayered oxide, promotes the full mixing and uniform dispersion of lithium ions and sodium ions required for the preparation of P2-type lithium-rich manganese sodium electrolayered oxide, compensates for the volatilization loss of sodium ions, and achieves a certain degree of homogeneity in the P2-type lithium-rich manganese sodium electrolayered oxide at a low calcination temperature. The process involves the fusion and growth of sub-nanoparticles and the preparation of micron-sized P2-type lithium-rich manganese sodium electrochemical layered oxides. Simultaneously, the micron-sized preparation strategy helps address the problems of easily broken and pulverized particles, severe interfacial side reactions, and mechanical-chemical contact failure and low tap density in solid-state batteries, as mentioned in the background technology for nanoscale polycrystalline materials. This facilitates good solid-solid interface contact between the O2-type lithium-rich manganese cathode material and the inorganic solid electrolyte, improving the volumetric energy density of solid-state lithium batteries. Finally, sulfidation or fluorination treatment of the micron-sized O2-type lithium-rich manganese cathode surface using sulfur or fluorine sources helps construct an electronically insulating and ion-conducting protective layer on the surface of the cathode active material, blocking interfacial side reactions between the cathode active material and the inorganic solid electrolyte and significantly improving the electrochemical performance of solid-state lithium batteries. Meanwhile, compared with the O2-type lithium-rich manganese cathode materials prepared in Comparative Examples 1-3, the method proposed in this invention, which combines the synergistic regulation of internal and external structures with the micronization of single cathode particles, overcomes the shortcomings of single-phase structure, surface property regulation, or single-particle micronization of O2-type lithium-rich manganese cathode materials. It effectively blocks the strong interaction and positive feedback between the bulk structure instability of the cathode material and the deterioration of the surface and interface structure, significantly improving the internal and external structural stability of the O2-type lithium-rich manganese cathode material and its good mechanical-chemical stability with inorganic solid electrolytes, thereby endowing it with excellent electrochemical performance in solid-state lithium batteries. Compared with the O3-type lithium-rich manganese cathode material with synergistic regulation of internal and external structures prepared in Comparative Example 4, the O2-type lithium-rich manganese cathode material prepared in this invention has the advantages of higher initial discharge capacity, higher initial coulombic efficiency, and higher cycle stability, demonstrating the intrinsic structural advantages of O2-type lithium-rich manganese-based cathode materials and their great application potential in solid-state lithium batteries.

Claims

1. A synergistically modified micron-sized O2-type lithium-rich manganese cathode material, characterized in that: The synergistically modified micron-sized O2-type lithium-rich manganese cathode material is an O2-type lithium-rich manganese cathode active material that has undergone bulk internal doping and external surface modification; wherein, the molecular formula of the O2-type lithium-rich manganese cathode active material is Li1(Li x Mn a TM y O2, wherein 0 < x ≤ 0.25, 0.3 ≤ a ≤ 0.7, 0.1 < y ≤ 0.6, and TM is a transition element of Ni and / or Co; the bulk doping element is one or more of Al, Ti or Zr; the external modification is the surface modification of the active material by means of a sulfur source or a fluorine source.

2. The synergistically modified micron-sized O2-type lithium-rich manganese cathode material according to claim 1, characterized in that: The synergistically modified micron-sized O2-type lithium-rich manganese cathode material is a primary particle of micron-sized O2-type lithium-rich manganese cathode material with a particle size of 0.5-5 μm.

3. A method for preparing the synergistically modified micron-sized O2-type lithium-rich manganese cathode material according to claim 1, characterized in that: 1) Based on the molecular formula of O2-type lithium-rich manganese cathode active material, the transition metal salt, the salt solution corresponding to the bulk doping element, the precipitant and the coordination agent are mixed, and the hydroxide precursor powder of O2-type lithium-rich manganese cathode active material with uniform doping modification in the bulk phase is prepared by co-precipitation method. 2) The hydroxide precursor powder for obtaining O2-type lithium-rich manganese positive electrode active material was mixed with sodium salt, lithium salt and flux by ball milling. The mixture was fused and grown in a high-temperature molten salt environment to obtain micron-sized P2-type lithium-rich manganese sodium electrode layered oxide doped in the bulk phase. 3) The above-obtained P2-type lithium-rich manganese sodium layered oxide and lithium salt mixture are subjected to ion exchange reaction in a low-temperature, molten salt environment to obtain a micron-sized O2-type lithium-rich manganese cathode material uniformly doped in the bulk phase. 4) The O2-type lithium-rich manganese cathode material obtained above is subjected to low-temperature heating treatment under vacuum conditions with a sulfur source or a fluorine source to obtain a micron-sized O2-type lithium-rich manganese cathode material with uniform doping in the bulk phase and surface modification.

4. The method for preparing the synergistically modified micron-sized O2-type lithium-rich manganese cathode material according to claim 3, characterized in that: In step 1), based on the molecular formula of the O2-type lithium-rich manganese cathode active material, salt solutions of transition metal elements and bulk dopants with a molar concentration of 0.5-3 mol / L, a precipitant with a molar concentration of 2-5 mol / L, and a ligand with a molar concentration of 0.5-6 mol / L are sequentially pumped into a nitrogen-filled reactor at flow rates of 0.1-5 ml / min, 0.2-6 ml / min, and 0.1-3 ml / min, respectively. The reaction is carried out continuously for 15-48 h under conditions of stirring speed of 500-1000 rpm, reaction temperature of 40-60 ℃, and reaction pH of 10.5-11.

5. Then, the reaction is allowed to proceed for 10-24 hours under conditions of stirring speed of 300-800 rpm, reaction temperature of 40-60 ℃, and reaction pH of 10.5-11.

5. The aging process involves aging the material with h followed by vacuum drying to obtain the hydroxide precursor powder of the O2-type lithium-rich manganese cathode active material; wherein the transition metal is Ni and / or Co transition elements, and the bulk dopant is one or more of Al, Ti, and Zr.

5. The method for preparing the synergistically modified micron-sized O2-type lithium-rich manganese cathode material according to claim 3, characterized in that: In step 2), the hydroxide precursor powder of the O2-type lithium-rich manganese positive electrode active material is mixed with sodium salt, lithium salt, and flux. The mixture is ball-milled in a molar ratio of 1:0.3-0.8:0.01-0.1:0.2-1.

5. The flux is sodium chloride.

6. The method for preparing the synergistically modified micron-sized O2-type lithium-rich manganese cathode material according to claim 3, characterized in that: In step 3), the ion exchange reaction between the micron-sized P2-type lithium-rich manganese sodium-ion layered oxide and the lithium salt mixture is carried out in a low-temperature, molten salt environment to obtain a micron-sized O2-type lithium-rich manganese cathode material uniformly doped in the bulk phase. The lithium salt mixture and the micron-sized P2-type lithium-rich manganese sodium-ion layered oxide are mixed in a ratio where the molar ratio of Li ions in the lithium salt mixture to Na ions in the micron-sized P2-type lithium-rich manganese sodium-ion layered oxide is greater than 10:1 to obtain a mixture system. The lithium salt mixture is a mixture of lithium nitrate and lithium chloride with a molar ratio of 88:12, and the molten salt environment is a molten salt environment provided by the mixture of lithium nitrate and lithium chloride at low temperature.

7. The application of the synergistically modified micron-sized O2-type lithium-rich manganese cathode material according to claim 1, characterized in that: Application of the micron-sized O2-type lithium-rich manganese cathode active material in the preparation of cathode materials.

8. A cathode material, characterized in that: Micron-sized O2-type lithium-rich manganese cathode material containing the synergistic modification described in claim 1.

9. An application of the cathode material according to claim 8, characterized in that: The application of the cathode material in the preparation of inorganic solid electrolyte all-solid-state batteries.

10. An all-solid-state battery with an inorganic solid electrolyte, characterized in that: The composite cathode material as described in claim 10.

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