A lithium-rich manganese-based substrate cathode material with both cation and anion doping, its preparation method and application

Abstract

This invention discloses a lithium-rich manganese-based substrate cathode material doped with both cations and anions, its preparation method, and its applications, relating to the field of lithium-ion battery technology. The material of this invention achieves synergistic modification by having cations and anions occupy different lattice sites, effectively suppressing unfavorable phase transitions during charge and discharge, mitigating capacity and voltage decay under long-cycle conditions, and significantly improving discharge specific capacity, cycle stability, and voltage retention. The preparation process of this invention is simple, easily controllable, and highly reproducible, suitable for large-scale industrial production. The resulting cathode material exhibits outstanding comprehensive electrochemical performance, meeting the requirements of high energy density, long cycle life, and high voltage stability for lithium-ion batteries in new energy vehicles, large-scale energy storage, and portable electronic devices, and has broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a lithium-rich manganese-based cathode material with both anion and cation doping, its preparation method, and its application. Background Technology

[0002] With the rapid development of new energy vehicles, large-scale energy storage, and portable electronic devices, lithium-ion batteries are placing increasingly stringent demands on the energy density, cycle life, and safety performance of cathode materials. Lithium-rich manganese-based layered cathode materials possess advantages such as high theoretical specific capacity, high operating voltage, and low raw material cost, making them one of the core candidate systems for next-generation high-energy-density lithium-ion battery cathode materials. This material has a layered crystal structure with alternating lithium and transition metal layers. During the first charge, in addition to the transition metal cations participating in the redox reaction, lattice oxygen can also participate in charge compensation, resulting in a reversible capacity significantly superior to traditional layered cathode materials.

[0003] However, lithium-rich manganese-based layered cathode materials still face numerous technical limitations in practical applications. Under high-voltage charge-discharge conditions, lattice oxygen participation in redox reactions easily leads to oxygen hole accumulation, lattice oxygen precipitation, and local structural rearrangement, causing the bulk and surface phases of the material to irreversibly transform from a layered structure to a spinel or rock salt phase. Simultaneously, during cycling, transition metal ions easily migrate from the transition metal layer to the lithium layer, crowding out lithium-ion diffusion channels, resulting in deteriorated lithium-ion migration kinetics, rate performance degradation, and a continuous decrease in discharge voltage. Furthermore, lattice oxygen instability and transition metal ion migration exhibit a coupling effect, further inducing rapid capacity decay, average voltage decline, and irreversible crystal structure evolution during long-cycle periods, severely restricting the commercialization and application of this type of material.

[0004] Currently, common modification methods for lithium-rich manganese-based substrate cathode materials mainly include bulk doping, surface coating, interface modification, anion doping, and morphology control. Among these, bulk doping, which can regulate the structure and electronic states from within the crystal, is the mainstream technical approach to improve the structural stability of the material. Conventional cation doping can improve material performance by strengthening local bonding strength, stabilizing the lattice framework, and regulating transition metal migration behavior. Anion doping, on the other hand, can optimize the coordination environment and local electronic structure of transition metals by replacing some lattice oxygen sites, thereby regulating lattice oxygen redox activity and inhibiting irreversible oxygen evolution. However, the modification dimensions of single cation or single anion doping are limited, and they cannot simultaneously solve the core problems of poor lattice oxygen stability, easy transition metal migration, and low anion redox reversibility, resulting in a significant bottleneck in modification effectiveness. Therefore, developing a dual-site synergistic doping modification strategy that can simultaneously achieve lattice oxygen stabilization, inhibit transition metal migration, and regulate anion redox behavior is a key technology that urgently needs to be mastered to improve the overall electrochemical performance of lithium-rich manganese-based substrate cathode materials. SUMMARY OF THE INVENTION

[0005] The object of the present invention is to provide a lithium-rich manganese-based layered cathode material with dual doping of cations and anions, and its preparation method and application, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions: The present invention provides a lithium-rich manganese-based layered cathode material with dual doping of cations and anions, and its chemical formula is Li 1.2 TM 0.8 M y N z O 2-y , where TM is a composite transition metal composed of Mn and Ni, and the molar ratio of Mn to Ni is 2.5 - 4.0; M is an anion doping element, selected from S or F; N is a cation doping element, selected from B, P or Si; 0 < y ≤ 0.3, 0 < z ≤ 0.3.

[0007] The cation doping elements B, P, Si occupy the crystal tetrahedral sites, and can form B-O, P-O, Si-O chemical bonds with high bond energy with the surrounding oxygen atoms, stabilize the local oxygen skeleton, improve the lattice oxygen structure stability under high voltage conditions, hinder the migration of transition metal ions into the lithium layer, and effectively inhibit the irreversible phase transformation from the layered phase to the spinel phase and the rock salt phase. When the doping coefficient z is too small, the lattice pinning and skeleton support effects are lacking; when z exceeds the upper limit, the excessive doping atoms will occupy the tetrahedral sites and block the Li + octahedron-tetrahedron-octahedron diffusion channels, inducing lattice distortion and precipitating borate, phosphate, silicate heterophases, so 0 < z ≤ 0.3 is defined. The anion doping elements S, F replace some oxygen sites in the lattice, optimize the coordination bonding environment of transition metals, inhibit the irreversible removal of lattice oxygen under high voltage, and reduce the transition metal migration and surface structure reconstruction of the material induced by oxygen vacancies. If the doping coefficient y is too low, it is difficult to achieve the oxygen lattice modification effect; if y is too high, it is easy to cause anion sublattice distortion, increase the lithium ion diffusion resistance and precipitate heterophases. Therefore, 0 < y ≤ 0.3 is defined.

[0008] This invention employs a dual-site synergistic doping strategy of cations and anions to achieve dual regulation of lattice oxygen stability and transition metal migration behavior in lithium-rich manganese-based layered cathode materials. On one hand, cation dopants preferentially occupy tetrahedral sites in the material lattice, forming stable BO, PO, or Si-O strong bonding structures with surrounding lattice oxygen. This enhances local oxygen coordination stability and spatially blocks the migration channels of transition metal ions to the lithium layer. On the other hand, anion dopants replace some lattice oxygen sites, constructing stable transition metal-anion bonding structures with transition metals. Simultaneously, they regulate the local electronic structure and anion redox behavior, effectively suppressing excessive oxidation of lattice oxygen, oxygen vacancy generation, and lattice oxygen precipitation. The synergistic effect of these two dopants stabilizes the layered crystal framework, suppresses irreversible structural phase transitions during charge and discharge, and significantly improves the material's structural stability, cycle life, and voltage retention.

[0009] This invention also provides a method for preparing the above-mentioned lithium-rich manganese-based substrate cathode material with both cation and anion doping, comprising the following steps: The Mn-Ni composite transition metal precursor was mixed with lithium salt, and then M source and N source were added. The mixture was heat-treated at 600-950℃ for 8-24 hours. After cooling, it was washed with water and dried to obtain an intermediate. The intermediate was calcined at 300-500°C to obtain the lithium-rich manganese-based cathode material with both cation and anion doping. The M source is an S source or an F source; the N source is a B source, a P source, or a Si source.

[0010] Furthermore, the calcination time is 2-10 hours.

[0011] Furthermore, the molar ratio of the Mn, Ni composite transition metal precursor to lithium ions in the lithium salt is 1:(1-5).

[0012] Furthermore, the Mn, Ni composite transition metal precursor is a transition metal carbonate, namely TMCO3; wherein TM is a composite transition metal composed of Mn and Ni.

[0013] Furthermore, the lithium salt is one or more of lithium carbonate, lithium hydroxide, lithium acetate, lithium nitrate, or lithium chloride.

[0014] Furthermore, the sulfur source is one or more of lithium sulfide, thiourea, thioacetamide, silicon sulfide, and ammonium sulfide; the fluorine source is one or more of lithium fluoride, ammonium fluoride, sodium fluoride, and potassium fluoride.

[0015] Further, the boron source is one or more of boric acid, boron oxide, lithium borate, and ammonium borate; the phosphorus source is one or more of phosphoric acid, phosphorus pentoxide, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate; and the silicon source is one or more of silicon dioxide, lithium silicate, silicon sulfide, tetraethyl silicate, and sodium silicate.

[0016] The preparation process of this invention is simple and can effectively improve the defects of traditional solid-phase methods, such as insufficient mixing of raw materials, uneven doping distribution, local component segregation, and large fluctuations in modification effect. It does not require complex equipment, the process parameters are easy to control, and the batch repeatability is good, making it suitable for large-scale production and industrial promotion.

[0017] The present invention further provides the application of the above-mentioned lithium-rich manganese-based substrate cathode material with both cation and anion doping in lithium-ion batteries.

[0018] This invention employs a dual-site synergistic doping mechanism of cations and anions, addressing the inherent defects of lithium-rich manganese-based materials, namely, the susceptibility to lattice oxygen instability and transition metal migration. The cation dopant, by occupying tetrahedral sites and forming a strong bond, acts as a lattice pinning agent, suppressing cation mixing and the irreversible transformation of layered structures into spinel and rock salt phases. The anion dopant, by occupying oxygen sites and regulating electronic states, improves the redox reversibility of anions, reducing the risk of lattice oxygen instability and precipitation. The structural solidification effect of cations and the electronic state regulation effect of anions synergistically achieve simultaneous lattice oxygen stabilization, transition metal migration suppression, voltage decay mitigation, and improved cycle performance.

[0019] The present invention discloses the following technical effects: This invention employs a dual-doping method with anions and cations to prepare lithium-rich manganese-based substrate cathode materials, significantly optimizing the overall electrochemical performance of the material through the synergistic effect of anions and cations. The cathode material of this invention can effectively suppress unfavorable phase transitions during charge and discharge, and significantly improve the capacity and voltage decay problems during long-cycle operation.

[0020] The preparation process of this invention is simple and controllable, with good process repeatability and low production threshold, making it suitable for industrial-scale preparation needs.

[0021] The dual-doped cathode material obtained by this invention has higher discharge specific capacity, excellent cycle stability and voltage retention capability. The material has excellent electrochemical performance and can be well adapted to the use requirements of new energy vehicles, large-scale energy storage and portable electronic devices for high energy density, long cycle life and high voltage stability of lithium-ion batteries. It has good practical application value and industrialization prospects. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The X-ray diffraction pattern is shown for the undoped lithium-rich manganese-based substrate cathode material powder in Example 1.

[0024] Figure 2 This is a SEM image of the undoped lithium-rich manganese-based basal cathode material powder from Example 1.

[0025] Figure 3 The undoped lithium-rich manganese-based substrate cathode material powder from Example 1 was used as the cathode at room temperature at 200 mA g. -1 The initial charge-discharge curve at that time.

[0026] Figure 4 The undoped lithium-rich manganese-based substrate cathode material powder from Example 1 was used as the cathode at room temperature at 200 mA g. -1 Capacity stability curve at that time.

[0027] Figure 5 The undoped lithium-rich manganese-based substrate cathode material powder from Example 1 was used as the cathode at room temperature at 200 mA g. -1 The voltage stability curve at that time.

[0028] Figure 6 The X-ray diffraction pattern of the S / Si anion and cation doped lithium-rich manganese-based substrate cathode material powder in Example 2 is shown.

[0029] Figure 7 This is a SEM image of the lithium-rich manganese-based substrate cathode material powder with S / Si dual doping of anions and cations in Example 2.

[0030] Figure 8 The S / Si dual-doped lithium-rich manganese-based substrate cathode material powder used in Example 2 was used as the cathode at room temperature at 200 mA g. -1 The initial charge-discharge curve at that time.

[0031] Figure 9 When the S / Si dual-doped lithium-rich manganese-based substrate cathode material powder in Example 2 is used as the cathode, the 200 mA g at room temperature... -1 Capacity stability curve.

[0032] Figure 10When the S / Si dual-doped lithium-rich manganese-based substrate cathode material powder in Example 2 is used as the cathode, the 200 mA g at room temperature... -1 Voltage stability curve. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0038] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0039] Example 1 (1) Preparation of intermediates: Weigh out 0.9271 g (i.e., 0.0080 mol) of the transition metal carbonate precursor (Mn). 0.75 Ni 0.25Add 0.4655 g (0.0063 mol) of lithium carbonate, 3.5784 g of potassium chloride, and 1.8701 g of sodium chloride to CO3, and grind for 20 min to ensure uniform grinding of all components. Then transfer to a muffle furnace and heat at 2 °C for 1 min. -1 The heating rate was increased to 780℃, and sintering was carried out at this temperature for 12 hours. After sintering, the temperature was increased by 5℃ per minute. -1 The temperature was lowered to 300℃, and then allowed to cool naturally to room temperature. The product cooled to room temperature was placed in 500 ml of ultrapure water and stirred for 30 min, followed by washing three times with deionized water to remove impurities. The washed sample was then dried at 180℃ for 8 h to obtain the intermediate.

[0040] (2) Preparation of undoped lithium-rich manganese-based basal cathode material powder: The above intermediate was transferred to a muffle furnace and heated to 2°C for 1 minute. -1 The heating rate was increased to 400℃, and sintering was carried out at this temperature for 3 hours. After sintering, the temperature was increased to 5℃ and then decreased by 0.5℃. -1 The temperature was lowered to 300℃, and then allowed to cool naturally to room temperature. This yielded undoped lithium-rich manganese-based substrate cathode material powder (chemical formula Li). 1.2 Mn 0.6 Ni 0.2 O2).

[0041] Figure 1 This is the X-ray diffraction pattern of the undoped lithium-rich manganese-based substrate cathode material powder in this embodiment. Figure 1 It can be seen that the synthesized powder is a mixed phase composed of hexagonal α-NaFeO2 (space group R-3m) and monoclinic Li2MnO3 (space group C2 / m). The main phase of the material has a typical layered structure, good crystallinity, and low degree of cation mixing.

[0042] Figure 2 SEM image of undoped lithium-rich manganese-based basal cathode material powder. From Figure 2 It can be seen that the synthesized cathode material powder is a micron-sized sphere assembled from irregular primary nanoparticles.

[0043] The test was conducted using coin cells. The undoped lithium-rich manganese-based substrate cathode material powder prepared above was mixed with a conductive agent (conductive carbon black) and a binder (polyvinylidene fluoride (PVDF)) at a mass ratio of 8:1:1 to form an electrode. A lithium metal sheet served as the counter electrode. 1 mol·L⁻¹ -1 LiPF6 and 0.2 mol·L -1The electrolyte is LiDFOB / FEC+EMC+EDFA (FEC:EMC:EDFA volume ratio 1:2:1), the separator is polypropylene, the battery testing system is NEWARE, the charge / discharge voltage window is 2.0–4.8V, and the charge / discharge current density is 200 mA g. -1 This material exhibits poor electrochemical performance when used as the positive electrode in lithium-ion batteries.

[0044] Figure 3 In this embodiment, the undoped lithium-rich manganese-based substrate cathode material powder is used as the cathode at room temperature (200 mA g). -1 The initial charge-discharge curve at that time. From Figure 3 It can be seen that at 200mA g -1 The initial discharge specific capacity at the charge / discharge current density is 264.52 mAh·g. -1 ; Figure 4 In this embodiment, the undoped lithium-rich manganese-based substrate cathode material powder, when used as the cathode, has a 200 mAg content at room temperature. -1 Capacity stability curve. From Figure 4 It can be seen that at 200mA g -1 At the specified charge / discharge current density, the capacity retention rate was 67.37% after 300 cycles. Figure 5 In this embodiment, the undoped lithium-rich manganese-based substrate cathode material powder is used as the cathode at room temperature (200 mA g). -1 Voltage stability curve. From Figure 5 It can be seen that at 200mAg -1 At the charge / discharge current density, the voltage decay rate is 0.93 mV / cycle between 20 and 300 cycles.

[0045] Example 2 (1) Preparation of intermediate: Weigh 0.9271 g (i.e. 0.0080 mol) of transition metal carbonate precursor (Mn 0.75 Ni 0.25 Add 0.4655 g (0.0063 mol) of lithium carbonate, 3.5784 g of potassium chloride, and 1.8701 g of sodium chloride to CO3, grind for 20 min, and after grinding until uniform, add 0.0092 g (0.0001 mol) of silicon disulfide (SiS2) and continue grinding for 10 min to ensure uniformity of all components; then transfer to a muffle furnace and heat at 2 °C for min. -1 The heating rate was increased to 780℃, and sintering was carried out at this temperature for 12 hours. After sintering, the temperature was increased by 5℃ per minute. -1The temperature was lowered to 300°C and then allowed to cool naturally to room temperature. The product cooled to room temperature was placed in 50 ml of ultrapure water and stirred for 30 min, followed by washing three times with deionized water to remove impurities. The washed sample was then dried at 180°C using a forced-air drying method to obtain the intermediate.

[0046] (2) Preparation of lithium-rich manganese-based substrate cathode material with both cation and anion doping: The above intermediate was transferred to a muffle furnace and heated to 2°C for 1 minute. -1 The heating rate was increased to 400℃, and sintering was carried out at this temperature for 3 hours. After sintering, the temperature was increased to 5℃ and then decreased by 0.5℃. -1 The temperature was lowered to 300℃, and then allowed to cool naturally to room temperature. This yielded S / Si dual-doped lithium-rich manganese-based substrate cathode material powder (chemical formula Li). 1.2 Mn 0.6 Ni 0.2 S 0.02 Si 0.01 O 1.98 ).

[0047] Figure 6 This is the X-ray diffraction pattern of the S / Si dual-doped lithium-rich manganese-based substrate cathode material powder in this embodiment. Figure 6 It can be seen that the synthesized powder is a mixed phase composed of hexagonal α-NaFeO2 (space group R-3m) and monoclinic Li2MnO3 (space group C2 / m). The main phase of the material has a typical layered structure, good crystallinity, and low degree of cation mixing.

[0048] Figure 7 SEM images of lithium-rich manganese-based substrate cathode material powders doped with both S / Si cations and anions. Figure 7 It can be seen that the synthesized cathode material powder is a micron-sized sphere assembled from irregular primary nanoparticles. Its surface morphology is rougher and it has a fine porous structure, which is beneficial to improving the wettability of the electrolyte in the material, thereby improving the lithium-ion transport kinetics.

[0049] The test was conducted using coin cells. The S / Si dual-doped lithium-rich manganese-based substrate cathode material powder prepared above was mixed with a conductive agent (conductive carbon black) and a binder (polyvinylidene fluoride (PVDF)) at a mass ratio of 8:1:1 to form an electrode. A lithium metal sheet served as the counter electrode. 1 mol·L⁻¹ -1 LiPF6 and 0.2 mol·L -1 The electrolyte is LiDFOB / FEC+EMC+EDFA (FEC:EMC:EDFA volume ratio 1:2:1), the separator is polypropylene, the battery testing system is NEWARE, the charge / discharge voltage window is 2.0–4.8V, and the charge / discharge current density is 200 mA g.-1 This material exhibits excellent electrochemical performance when used as the positive electrode in lithium-ion batteries.

[0050] Figure 8 In this embodiment, the S / Si dual-doped lithium-rich manganese-based substrate cathode material powder, when used as the cathode, achieves 200 mA g at room temperature. -1 The first charge-discharge curve at that time; from Figure 8 It can be seen that at 200mA g -1 The initial discharge specific capacity at the charge / discharge current density is 268.79 mAh g. -1 . Figure 9 In this embodiment, the S / Si dual-doped lithium-rich manganese-based substrate cathode material powder, when used as the cathode, achieves 200 mA g at room temperature. -1 Capacity stability curve; from Figure 9 It can be seen that at 200mA g -1 At the charge / discharge current density, the capacity retention rate is 93.34% after 300 cycles. Figure 10 In this embodiment, the lithium-rich manganese-based substrate cathode material powder, doped with both cations and anions, is used as the cathode at room temperature at 200 mA g. -1 Voltage stability curve; from Figure 10 It can be seen that at 200mA g -1 At the charge / discharge current density, the voltage decay rate is 0.66 mV / cycle between 20 and 300 cycles.

[0051] Example 3 (1) Preparation of intermediates: Weigh out 0.9271 g (i.e., 0.0080 mol) of the transition metal carbonate precursor (Mn). 0.75 Ni 0.25 Add 0.4655 g (0.0063 mol) of lithium salt A (anhydrous lithium carbonate Li₂CO₃), 3.5784 g of potassium chloride (KCl), and 1.8701 g of sodium chloride (NaCl) to CO₃. Grind for 20 min. After homogenization, add 0.0074 g (0.0002 mol) of ammonium fluoride (NH₄F) and 0.0115 g (0.0001 mol) of ammonium dihydrogen phosphate (NH₄H₂PO₄), and continue grinding for 10 min to ensure uniformity of all components. Then transfer to a muffle furnace and heat at 2 °C for 1 min. -1 The heating rate was increased to 780℃, and sintering was carried out at this temperature for 12 hours. After sintering, the temperature was increased by 5℃ per minute. -1The temperature was lowered to 300°C and then allowed to cool naturally to room temperature. The product cooled to room temperature was placed in 50 ml of ultrapure water and stirred for 30 min, followed by washing three times with deionized water to remove impurities. The washed sample was then dried at 180°C using a forced-air drying method to obtain the intermediate.

[0052] (2) Preparation of lithium-rich manganese-based substrate cathode material with both cation and anion doping: The above intermediate was transferred to a muffle furnace and heated to 2°C for 1 minute. -1 The heating rate was increased to 400℃, and sintering was carried out at this temperature for 3 hours. After sintering, the temperature was increased to 5℃ and then decreased by 0.5℃. -1 The temperature was lowered to 300℃, and then allowed to cool naturally to room temperature. This yielded F / P dual-doped lithium-rich manganese-based substrate cathode material powder (chemical formula Li). 1.2 Mn 0.6 Ni 0.2 F 0.02 P 0.01 O 1.98 ).

[0053] Electrochemical performance was tested using coin cells. The positive electrode material powder prepared in this embodiment was mixed with conductive carbon black (conductive agent) and polyvinylidene fluoride (PVDF) (binder) at a mass ratio of 8:1:1 to prepare an electrode sheet. A lithium metal sheet was used as the counter electrode. (1 mol•L) - 1 LiPF6 and 0.2 mol•L -1 The electrolyte was a LiDFOB composite salt and a mixed solvent of FEC, EMC, and EDFA, with polypropylene as the separator. Testing was conducted on a NEWARE battery testing system, with a charge / discharge voltage window of 2.0–4.8 V and a current density of 200 mA·g. -1 .

[0054] Example 4 (1) Preparation of intermediate: Weigh 0.9271 g (i.e. 0.0080 mol) of transition metal carbonate precursor (Mn 0.75 Ni 0.25 Add 0.4655 g (0.0063 mol) of lithium salt A (anhydrous lithium carbonate Li₂CO₃), 3.5784 g of potassium chloride (KCl), and 1.8701 g of sodium chloride (NaCl). Grind for 20 min. After homogenization, add 0.0152 g of thiourea (0.0002 mol) (CH₄N₂S) and 0.0115 g (0.0001 mol) of ammonium dihydrogen phosphate (NH₄H₂PO₄). Continue grinding for 10 min to ensure uniformity of all components. Then transfer to a muffle furnace and heat at 2 °C for 1 min. -1The heating rate was increased to 780℃, and sintering was carried out at this temperature for 12 hours. After sintering, the temperature was increased by 5℃ per minute. -1 The temperature was lowered to 300°C and then allowed to cool naturally to room temperature. The product cooled to room temperature was placed in 50 ml of ultrapure water and stirred for 30 min, followed by washing three times with deionized water to remove impurities. The washed sample was then dried at 180°C using a forced-air drying method to obtain the intermediate.

[0055] (2) Preparation of lithium-rich manganese-based substrate cathode material with both cation and anion doping: The above intermediate was transferred to a muffle furnace and heated to 2°C for 1 minute. -1 The heating rate was increased to 400℃, and sintering was carried out at this temperature for 3 hours. After sintering, the temperature was increased to 5℃ and then decreased by 0.5℃. -1 The temperature was lowered to 300℃, and then allowed to cool naturally to room temperature. This yielded S / P dual-doped lithium-rich manganese-based substrate cathode material powder (chemical formula Li). 1.2 Mn 0.6 Ni 0.2 S 0.02 P 0.01 O 1.98 ).

[0056] Electrochemical performance was tested using coin cells. The positive electrode material powder prepared in this embodiment was mixed with conductive carbon black (conductive agent) and polyvinylidene fluoride (PVDF) (binder) at a mass ratio of 8:1:1 to prepare an electrode sheet. A lithium metal sheet was used as the counter electrode. (1 mol•L) - 1 LiPF6 and 0.2 mol•L -1 The electrolyte was a LiDFOB composite salt and a mixed solvent of FEC, EMC, and EDFA, with polypropylene as the separator. Testing was conducted on a NEWARE battery testing system, with a charge / discharge voltage window of 2.0–4.8 V and a current density of 200 mA·g. -1 .

[0057] Example 5 (1) Preparation of intermediates: Weigh out 0.9271 g (i.e., 0.0080 mol) of the transition metal carbonate precursor (Mn). 0.75 Ni 0.25Add 0.4655 g (0.0063 mol) of lithium salt A (anhydrous lithium carbonate Li₂CO₃), 3.5784 g of potassium chloride (KCl), and 1.8701 g of sodium chloride (NaCl) to CO₃. Grind for 20 min. After homogenization, add 0.0152 g of thiourea (0.0002 mol) (CH₄N₂S) and 0.0062 g (0.0001 mol) of boric acid (H₃BO₃), and continue grinding for 10 min to ensure uniformity of all components. Then transfer to a muffle furnace and heat at 2 °C for min. -1 The heating rate was increased to 780℃, and sintering was carried out at this temperature for 12 hours. After sintering, the temperature was increased by 5℃ / min. -1 The temperature was lowered to 300°C and then allowed to cool naturally to room temperature. The product cooled to room temperature was placed in 50 ml of ultrapure water and stirred for 30 min, followed by washing three times with deionized water to remove impurities. The washed sample was then dried at 180°C using a forced-air drying method to obtain the intermediate.

[0058] (2) Preparation of lithium-rich manganese-based substrate cathode material with both cation and anion doping: The above intermediate was transferred to a muffle furnace and heated to 2°C for 1 minute. -1 The heating rate was increased to 400℃, and sintering was carried out at this temperature for 3 hours. After sintering, the temperature was increased to 5℃ and then decreased by 0.5℃. -1 The temperature was lowered to 300℃, and then allowed to cool naturally to room temperature. This yielded S / B dual-doped lithium-rich manganese-based substrate cathode material powder (chemical formula Li). 1.2 Mn 0.6 Ni 0.2 S 0.02 B 0.01 O 1.98 ).

[0059] Electrochemical performance was tested using coin cells. The positive electrode material powder prepared in this embodiment was mixed with conductive carbon black (conductive agent) and polyvinylidene fluoride (PVDF) (binder) at a mass ratio of 8:1:1 to prepare an electrode sheet. A lithium metal sheet was used as the counter electrode. (1 mol•L) - 1 LiPF6 and 0.2 mol•L -1 The electrolyte was a LiDFOB composite salt and a mixed solvent of FEC, EMC, and EDFA, with polypropylene as the separator. Testing was conducted on a NEWARE battery testing system, with a charge / discharge voltage window of 2.0–4.8 V and a current density of 200 mA·g. -1 .

[0060] Comparative Example 1 (1) Preparation of intermediates: Weigh out 0.9271 g (i.e., 0.0080 mol) of the transition metal carbonate precursor (Mn). 0.75 Ni 0.25 Add 0.4655 g (0.0063 mol) of lithium salt A (anhydrous lithium carbonate Li₂CO₃), 3.5784 g of potassium chloride (KCl), and 1.8701 g of sodium chloride (NaCl) to CO₃. Grind for 20 min. After grinding until homogeneous, add 0.0152 g of thiourea (0.0002 mol) (CH₄N₂S) and continue grinding for 10 min to ensure uniformity of all components. Then transfer to a muffle furnace and heat at 2 °C for min. -1 The heating rate was increased to 780℃, and sintering was carried out at this temperature for 12 hours. After sintering, the temperature was increased by 5℃ per minute. -1 The temperature was lowered to 300°C and then allowed to cool naturally to room temperature. The product cooled to room temperature was placed in 50 ml of ultrapure water and stirred for 30 min, followed by washing three times with deionized water to remove impurities. The washed sample was then dried at 180°C using a forced-air drying method to obtain the intermediate.

[0061] (2) Preparation of single-ion doped lithium-rich manganese-based substrate cathode material: The above intermediate was transferred to a muffle furnace and heated to 2°C for 1 minute. -1 The heating rate was increased to 400℃, and sintering was carried out at this temperature for 3 hours. After sintering, the temperature was increased to 5℃ and then decreased by 0.5℃. -1 The temperature was lowered to 300℃, and then allowed to cool naturally to room temperature. This yielded S-doped lithium-rich manganese-based cathode material powder (chemical formula Li). 1.2 Mn 0.6 Ni 0.2 S 0.02 O 1.98 ).

[0062] Electrochemical performance was tested using coin cells. The positive electrode material powder prepared in this embodiment was mixed with conductive carbon black (conductive agent) and polyvinylidene fluoride (PVDF) (binder) at a mass ratio of 8:1:1 to prepare an electrode sheet. A lithium metal sheet was used as the counter electrode. (1 mol•L) - 1 LiPF6 and 0.2 mol•L -1 The electrolyte was a LiDFOB composite salt and a mixed solvent of FEC, EMC, and EDFA, with polypropylene as the separator. Testing was conducted on a NEWARE battery testing system, with a charge / discharge voltage window of 2.0–4.8 V and a current density of 200 mA·g. -1 .

[0063] Comparative Example 2 (1) Preparation of intermediates: Weigh out 0.9271 g (i.e., 0.0080 mol) of the transition metal carbonate precursor (Mn). 0.75 Ni 0.25 Add 0.4655 g (0.0063 mol) of lithium salt A (anhydrous lithium carbonate Li₂CO₃), 3.5784 g of potassium chloride (KCl), and 1.8701 g of sodium chloride (NaCl) to CO₃²⁻. Grind for 20 min until homogeneous. Then add 0.0062 g (0.0001 mol) of boric acid (H₃BO₃) and continue grinding for 10 min to ensure uniformity of all components. Transfer the mixture to a muffle furnace and heat at 2 °C for [time missing]. -1 The heating rate was increased to 780℃, and sintering was carried out at this temperature for 12 hours. After sintering, the temperature was increased by 5℃ per minute. -1 The temperature was lowered to 300°C and then allowed to cool naturally to room temperature. The product cooled to room temperature was placed in 50 ml of ultrapure water and stirred for 30 min, followed by washing three times with deionized water to remove impurities. The washed sample was then dried at 180°C using a forced-air drying method to obtain the intermediate.

[0064] (2) Preparation of single-ion doped lithium-rich manganese-based substrate cathode material: The above intermediate was transferred to a muffle furnace and heated to 2°C for 1 minute. -1 The heating rate was increased to 400℃, and sintering was carried out at this temperature for 3 hours. After sintering, the temperature was increased to 5℃ and then decreased by 0.5℃. -1 The temperature was lowered to 300℃, and then allowed to cool naturally to room temperature. This yielded B-doped lithium-rich manganese-based cathode material powder (chemical formula Li). 1.2 Mn 0.6 Ni 0.2 B 0.01 O2).

[0065] Electrochemical performance was tested using coin cells. The positive electrode material powder prepared in this embodiment was mixed with conductive carbon black (conductive agent) and polyvinylidene fluoride (PVDF) (binder) at a mass ratio of 8:1:1 to prepare an electrode sheet. A lithium metal sheet was used as the counter electrode. (1 mol•L) - 1 LiPF6 and 0.2 mol•L -1 The electrolyte was a LiDFOB composite salt and a mixed solvent of FEC, EMC, and EDFA, with polypropylene as the separator. Testing was conducted on a NEWARE battery testing system, with a charge / discharge voltage window of 2.0–4.8 V and a current density of 200 mA·g. -1 .

[0066] According to the above electrochemical testing conditions, the cathode materials prepared in Examples 3-5 and Comparative Examples 1-2 were characterized for electrochemical performance at room temperature. The initial discharge specific capacity, capacity retention after 300 cycles, and average voltage decay rate after 20-300 cycles were tested for each sample. The specific electrochemical performance test results are shown in Table 1. It can be seen that compared with undoped and single-doped lithium-rich manganese-based substrate cathode materials, the cathode materials modified by dual doping of anions and cations in this invention exhibit superior discharge specific capacity, cycle stability, and voltage stability.

[0067] Table 1 This invention employs a dual-site synergistic doping approach with both cations and anions to address the inherent challenges of lithium-rich manganese-based layered cathode materials, such as lattice oxygen instability and transition metal migration. A structure-electronic dual-regulation strategy is constructed. Cation dopants preferentially occupy tetrahedral sites in the material's lattice, forming stable cation-oxygen strong bonds with surrounding lattice oxygen. This effectively enhances local oxygen coordination stability and spatially blocks the migration path of transition metal ions to the lithium layer, suppressing cation mixing during cycling and the irreversible phase transition from layered structures to spinel and rock salt phases. Anion dopants replace some lattice oxygen sites, constructing stable transition metal-anion bonds with transition metals. Simultaneously, they regulate the local electronic structure and anion redox behavior, mitigating excessive lattice oxygen oxidation, reducing oxygen vacancy generation and lattice oxygen evolution, and improving the reversibility of anion redox reactions from an electronic structure perspective. Cation doping plays a role in pinning the crystal structure, while anion doping enables precise control of the electronic state of oxygen sites. The two work synergistically to improve the lattice oxygen stability, transition metal migration suppression, voltage stability, and long cycle life of lithium-rich manganese-based substrate cathode materials.

[0068] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A lithium-rich manganese-based substrate cathode material with both cation and anion doping, characterized in that, The chemical formula is Li 1.2 TM 0.8 M y N z O 2-y TM is a composite transition metal composed of Mn and Ni, wherein the molar ratio of Mn to Ni is 2.5~4.0; M is an anion dopant selected from S or F; N is a cation dopant selected from B, P or Si; 0 <y≤0.3,0<z≤0.3。 2. The method for preparing the lithium-rich manganese-based substrate cathode material with both cation and anion doping as described in claim 1, characterized in that, Includes the following steps: The Mn-Ni composite transition metal precursor was mixed with lithium salt, and then M source and N source were added. The mixture was heat-treated at 600-950℃ for 8-24 hours. After cooling, it was washed with water and dried to obtain an intermediate. The intermediate was calcined at 300-500°C to obtain the lithium-rich manganese-based cathode material with both cation and anion doping. The M source is at least one of an S source or an F source; the N source is a B source, a P source, or a Si source.

3. The preparation method according to claim 2, characterized in that, The calcination time is 2-10 hours.

4. The preparation method according to claim 2, characterized in that, The molar ratio of the Mn, Ni composite transition metal precursor to lithium ions in the lithium salt is 1:(1-5).

5. The preparation method according to claim 2, characterized in that, The Mn, Ni composite transition metal precursor is a transition metal carbonate, namely TMCO3; wherein TM is a composite transition metal composed of Mn and Ni.

6. The preparation method according to claim 2, characterized in that, The lithium salt is one or more of lithium carbonate, lithium hydroxide, lithium acetate, lithium nitrate, or lithium chloride.

7. The preparation method according to claim 2, characterized in that, The sulfur source is one or more of lithium sulfide, thiourea, thioacetamide, silicon sulfide, and ammonium sulfide; the fluorine source is one or more of lithium fluoride, ammonium fluoride, sodium fluoride, and potassium fluoride.

8. The preparation method according to claim 2, characterized in that, The boron source is one or more of boric acid, boron oxide, lithium borate, and ammonium borate; the phosphorus source is one or more of phosphoric acid, phosphorus pentoxide, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate; and the silicon source is one or more of silicon dioxide, lithium silicate, silicon sulfide, tetraethyl silicate, and sodium silicate.

9. The application of the lithium-rich manganese-based substrate cathode material with both anion and cation doping as described in claim 1 in lithium-ion batteries.

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