Lithium-rich manganese-based material for lithium supplementation of ternary material and silicon-based lithium battery system and preparation method of lithium-rich manganese-based material

Abstract

The invention discloses a lithium-rich manganese-based material for lithium supplementation of a ternary material and a silicon-based lithium battery system and a preparation method of the lithium-rich manganese-based material, and relates to the technical field of lithium ion battery positive electrode materials. The preparation method comprises the following steps: reacting a mixed solution of Mn salt, Ni salt, Co salt and urea at 180-200 DEG C, cooling, washing, drying, grinding and mixing the obtained carbonate precursor and lithium carbonate, and calcining the obtained mixed material to obtain the lithium-rich manganese-based material Li < 1.2 > Mn < 0.54 > Ni < 0.13 > Co < 0.13 > O2. The preparation method is simple and easy to operate, the prepared lithium-rich manganese-based material is excellent in performance, when the lithium-rich manganese-based material is applied to a ternary material-silicon-based lithium battery system, the specific capacity can be improved, the cycling stability can be enhanced, the first-effect loss can be compensated, the volume expansion damage can be relieved, an SEI film can be optimized, the first coulombic efficiency and the long-cycle performance of a battery can be remarkably improved, and the service life of the battery can be prolonged. And the performance breakthrough of a high-energy density battery system is effectively assisted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion battery cathode materials, in particular to a lithium-rich manganese-based material for lithium supplement of a ternary material and a silicon-based lithium battery system and a preparation method thereof. BACKGROUND

[0002] With the rapid development of new energy vehicles and energy storage technology, lithium ion batteries as the core energy storage and conversion components have increasingly urgent demand for high energy density and long cycle life. The combination of ternary materials (such as lithium nickel cobalt manganese oxide (NCM) and lithium nickel cobalt aluminum oxide (NCA)) and silicon-based anodes (such as silicon-carbon composite materials) has become the core research direction of the next generation of high energy density lithium ion batteries due to its high energy density potential. However, this technology system still faces multiple challenges: on the one hand, silicon-based anodes will undergo significant volume expansion during lithium intercalation, leading to repeated rupture and reconstruction of the solid electrolyte interface (SEI) film, continuous consumption of active lithium ions and irreversible capacity decay; on the other hand, ternary cathode materials are prone to transition metal dissolution and structural phase transition at high voltage, further exacerbating capacity loss.

[0003] To alleviate the above problems, existing technologies often use lithium supplement agents (such as lithium-rich lithium iron oxide) to supplement lithium loss during the first charge and discharge process and lithium ion loss during the cycle process to improve the first coulombic efficiency and stabilize the cycle performance. However, the application of traditional lithium supplement agents still has significant defects: for example, Li2NiO2 is prone to side reactions with electrolyte at high temperatures, releasing gas and causing battery swelling, which threatens safety performance; organic lithium salt lithium supplement agents may introduce impurity ions, interfere with the stability of the electrode / electrolyte interface, and reduce the overall performance of the battery; in addition, the preparation process of some lithium supplement agents is complex, requiring high-precision equipment and harsh operating conditions, significantly increasing production costs. These technical bottlenecks have seriously restricted the large-scale application of silicon-based-ternary systems in high energy density lithium ion batteries, and there is an urgent need to develop new solutions that have high lithium supplement efficiency, environmental stability and process compatibility. SUMMARY

[0004] The purpose of the present application is to provide a lithium-rich manganese-based material for lithium supplement of a ternary material and a silicon-based lithium battery system and a preparation method thereof to solve the problems existing in the prior art.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] One of the technical solutions of the present application is to provide a lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2, and a preparation method thereof, comprising the following steps:

[0007] S1. mixing Mn salt, Ni salt, Co salt with urea in a solvent to obtain a mixed solution;

[0008] S2. reacting the mixed solution at 180-200℃ for 20-28h, cooling, washing, drying to obtain a carbonate precursor;

[0009] S3. grinding and mixing the carbonate precursor with lithium carbonate to obtain a mixture;

[0010] S4. calcining the mixture at 400℃ for 4h, and then calcining at 750-850℃ for 10-20h, cooling to obtain the lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2;

[0011] The ratio of the molar amount of urea to the total molar amount of Mn, Ni and Co is 2-3:1;

[0012] The mass ratio of the carbonate precursor to lithium carbonate is 1:0.4-0.7.

[0013] As a further preferred embodiment of the present application, the Mn salt, Ni salt and Co salt are all acetate salts.

[0014] As a further preferred embodiment of the present application, the drying temperature in step S2 is 70-90℃, and the drying time is 10-14h.

[0015] As a further preferred embodiment of the present application, step S1 comprises the following steps:

[0016] a. dissolving Mn salt, Ni salt and Co salt in a first solvent according to a molar ratio of Mn:Ni:Co of 0.54:0.13:0.13 to obtain a transition metal solution; dissolving urea in a second solvent to obtain a urea solution;

[0017] b. mixing the transition metal solution with the urea solution to obtain the mixed solution.

[0018] As a further preferred embodiment of the present application, the urea solution is dropped into the transition metal solution at a rate of 5-6mL / min.

[0019] As a further preferred embodiment of the present application, the concentration of the transition metal solution is 0.2-0.8mol / L; and the concentration of the urea solution is 0.5-1.5mol / L.

[0020] As a further preferred embodiment of the present application, the first solvent is ethylene glycol, and the second solvent is ethanol.

[0021] The second technical solution of the present application provides the lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 prepared by the preparation method.

[0022] The third technical solution of the present application provides the application of the lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 as a positive electrode material lithium supplement for a lithium battery.

[0023] As a further preferred embodiment of the present application, the positive electrode material of the lithium battery is a ternary material, and the negative electrode material is a silicon-based material.

[0024] As a further preferred embodiment of the present application, the lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 is added to the positive electrode material in an amount of 3-10 wt.%.

[0025] The present application successfully prepares a lithium-rich manganese-based material by a simple method, which is used as a lithium supplement for ternary materials and silicon-carbon materials, and has remarkable effects: in a ternary material system, the lithium loss in the first charge-discharge process can be effectively supplemented, and the specific capacity of the material is improved; at the same time, the excellent layered structure can reduce the charge-discharge polarization, stabilize the material crystal structure, and significantly enhance the cycle stability of the ternary material; for silicon-carbon materials, the huge initial loss of the silicon negative electrode can be compensated in the pre-lithiation process, and lithium ions are continuously provided in the cycle process, which can alleviate the structure damage of the silicon-carbon material caused by volume expansion; the stable chemical properties can also optimize the SEI film on the material surface, inhibit the continuous decomposition of the electrolyte, and further improve the long cycle performance of the silicon-carbon negative electrode.

[0026] The present application has the following technical effects:

[0027] The present application successfully prepares a lithium-rich manganese-based material by a simple method, which is used as a lithium supplement for ternary materials and silicon-carbon materials, and has remarkable effects: in a ternary material system, the lithium loss in the first charge-discharge process can be effectively supplemented, and the specific capacity of the material is improved; at the same time, the excellent layered structure can reduce the charge-discharge polarization, stabilize the material crystal structure, and significantly enhance the cycle stability of the ternary material; for silicon-carbon materials, the huge initial loss of the silicon negative electrode can be compensated in the pre-lithiation process, and lithium ions are continuously provided in the cycle process, which can alleviate the structure damage of the silicon-carbon material caused by volume expansion; the stable chemical properties can also optimize the SEI film on the material surface, inhibit the continuous decomposition of the electrolyte, and further improve the long cycle performance of the silicon-carbon negative electrode. 1.2 Mn 0.54 Ni 0.13 Co 0.13The prepared lithium-rich manganese-based material has excellent performance, the D50 particle size is controlled in 1-5 μm, can be uniformly dispersed in the electrode slurry, is beneficial to lithium ion transmission, the first coulombic efficiency is 50%-65%, can release sufficient lithium ions to supplement battery loss, when applied to a ternary material-silicon-based lithium battery system, can improve specific capacity and enhance cycle stability, compensate for the loss of first efficiency, relieve volume expansion damage and optimize SEI film, significantly improve the first coulombic efficiency and long cycle performance of the battery, and effectively help performance breakthrough of high-energy-density battery systems. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 The micro-morphology diagram of the precursor powder prepared for the present application embodiment 1.

[0030] Figure 2 The SEM diagram and particle size distribution diagram of the lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 prepared for the present application embodiment 1.

[0031] Figure 3 The SEM diagram and particle size distribution diagram of the lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 prepared for the present application embodiment 1.

[0032] Figure 4 The SEM diagram and energy spectrum analysis of the lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 prepared for the present application embodiment 1.

[0033] Figure 5 The capacity retention rate curve of the 2025 button cell prepared for the present application embodiment 1 and comparative example 1. DETAILED DESCRIPTION

[0034] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present application.

[0035] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Additionally, for a range of values of a parameter, unless otherwise stated, the inclusion of either extremity of the range is to be understood as if both are stated. For example, "from 1 to 10" should be interpreted as meaning "from 1 to 10 as well as 1 to 10".

[0036] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice of the present application. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the present specification and any document incorporated by reference, the present specification will control.

[0037] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application.

[0038] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having" or variants thereof are open-ended, and specifically do not exclude additional, unrecited elements or method steps.

[0039] It should be noted that the present application is not limited by what has been particularly shown and described hereinabove; reference should be made to the appended claims to determine the scope of the application.

[0040] Example 1

[0041] (1) Accurately weigh 2.6 g (0.0106 mol) of manganese acetate tetrahydrate, 0.636 g (0.00256 mol) of nickel acetate tetrahydrate, 0.638 g (0.00256 mol) of cobalt acetate tetrahydrate, and dissolve them in 23.4 mL of ethylene glycol to prepare a mixed acetate solution with a total metal ion concentration of 0.67 mol / L.

[0042] (2) Accurately weigh 1.9 g (0.0317 mol) of urea, and dissolve it in 46.6 mL of anhydrous ethanol to prepare a urea-ethanol mixed solution with a concentration of 0.68 mol / L.

[0043] (3) Slowly add the urea-ethanol mixture from step (2) to the acetate mixture from step (1), stirring continuously during the addition process. After the addition is complete, continue stirring for 2 hours to obtain a homogeneous mixture.

[0044] (4) Transfer the homogeneous mixed solution from step (3) to a polytetrafluoroethylene-lined reactor, seal it, and place it in a constant temperature drying oven. React at 190°C for 20 hours. After the reaction is complete, allow it to cool naturally to room temperature to obtain a carbonate precursor precipitate.

[0045] (5) The carbonate precursor precipitate mixture from step (4) was filtered with water until neutral, then washed three times with ethanol, and the filter cake was collected and dried in an oven at 70°C for 12 hours to obtain pink precursor powder.

[0046] (6) Weigh 1.5g of precursor powder and 0.8056g of lithium carbonate into a mortar and grind them thoroughly to obtain a uniform mixture.

[0047] (7) The mixture obtained in step (6) is placed into a crucible and then into a muffle furnace. The temperature is increased to 400℃ at 5℃ / min and held for 4 hours. Then the temperature is increased to 800℃ at 5℃ / min and held for 12 hours. After natural cooling, black lithium-rich manganese-based material Li is obtained. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2.

[0048] The prepared lithium-rich manganese-based material was used as a lithium supplement agent and mixed with NCM523 cathode material at an addition amount of 10 wt.% to prepare a cathode sheet.

[0049] NCM523, Super P, and PVDF were dispersed in NMP at a mass ratio of 8:1:1, and Li was added at 10% relative to NCM523. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2 forms a uniform slurry, which is then coated onto aluminum foil. The resulting electrode is dried at 100°C for 10 hours and then stamped into a circular positive electrode with a diameter of 12 mm. For the positive electrode, the mass loading density is controlled at 4 mg·cm³. -2 .

[0050] The prepared positive electrode and lithium negative electrode were assembled into a 2032 coin cell (using lithium hexafluorophosphate electrolyte (1MLiPF6 in DEC:EC:EMC = 1:1:1V)) and its first-cycle performance and cycle performance were tested. Material performance data are shown in Table 1.

[0051] The prepared positive electrode sheet and silicon-carbon negative electrode sheet were assembled into a 2025 coin cell (using lithium hexafluorophosphate electrolyte (1MLiPF6 in DEC:EC:EMC = 1:1:1V)). Its first-cycle performance and cycle life were tested. Material performance data are shown in Table 2, and the cycle life curves are shown in... Figure 5 As shown. The negative electrode uses Gr-Si@C as the active material, Super P as the electronic conductive agent, and CMC and SBR as binders in a mass ratio of 76:4:10:4:6. An aqueous slurry containing Gr, Si@C, Super P, CMC, and SBR binders was prepared and coated onto copper foil. The resulting electrode was dried at 80°C for 10 hours and then stamped into a circular electrode with a diameter of 12 mm. For the Gr-Si@C active material, the mass loading density of the electrode was maintained at 1.7 mg·cm³. -2 .

[0052] The battery cycle performance test method is as follows: In the first cycle, charge to 4.6V with a current density of 0.1C, let stand for 3 minutes, and then discharge to 2.5V. After that, test and evaluate its cycle life with a current density of 0.5C in the voltage range of 2.5-4.4V.

[0053] Example 2

[0054] (1) Accurately weigh 2.6 g (0.0106 mol) of manganese acetate tetrahydrate, 0.636 g (0.00256 mol) of nickel acetate tetrahydrate, and 0.638 g (0.00256 mol) of cobalt acetate tetrahydrate, dissolve them in 23.4 mL of ethylene glycol, and prepare a mixed acetate solution with a total metal ion concentration of 0.67 mol / L.

[0055] (2) Accurately weigh 1.9g (0.0317mol) of urea and dissolve it in 46.6mL of anhydrous ethanol to prepare a 0.68mol / L urea-ethanol mixed solution.

[0056] (3) Slowly add the urea-ethanol mixture from step (2) to the acetate mixture from step (1), stirring continuously during the addition process. After the addition is complete, continue stirring for 2 hours to obtain a homogeneous mixture.

[0057] (4) Transfer the homogeneous mixed solution from step (3) to a polytetrafluoroethylene-lined reactor, seal it, and place it in a constant temperature drying oven. React at 190°C for 20 hours. After the reaction is complete, allow it to cool naturally to room temperature to obtain a carbonate precursor precipitate.

[0058] (5) The carbonate precursor precipitate mixture from step (4) was filtered with water until neutral, then washed three times with ethanol, and the filter cake was collected and dried in an oven at 70°C for 12 hours to obtain pink precursor powder.

[0059] (6) Weigh 1.5g of precursor powder and 0.7161g of lithium carbonate into a mortar and grind them thoroughly to obtain a uniform mixture.

[0060] (7) The mixture obtained in step (6) is placed into a crucible and then into a muffle furnace. The temperature is increased to 400℃ at 5℃ / min and held for 4 hours. Then the temperature is increased to 800℃ at 5℃ / min and held for 12 hours. After natural cooling, black lithium-rich manganese-based material Li is obtained. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2.

[0061] The prepared lithium-rich manganese-based material was used as a lithium supplement agent and mixed with NCM523 cathode material at an addition amount of 10 wt.% to prepare a cathode sheet.

[0062] The performance test was conducted using the same method as in Example 1.

[0063] Example 3

[0064] (1) Accurately weigh 2.6 g (0.0106 mol) of manganese acetate tetrahydrate, 0.636 g (0.00256 mol) of nickel acetate tetrahydrate, and 0.638 g (0.00256 mol) of cobalt acetate tetrahydrate, dissolve them in 23.4 mL of ethylene glycol, and prepare a mixed acetate solution with a total metal ion concentration of 0.67 mol / L.

[0065] (2) Accurately weigh 1.9g (0.0317mol) of urea and dissolve it in 46.6mL of anhydrous ethanol to prepare a 0.68mol / L urea-ethanol mixed solution.

[0066] (3) Slowly add the urea-ethanol mixture from step (2) to the acetate mixture from step (1), stirring continuously during the addition process. After the addition is complete, continue stirring for 2 hours to obtain a homogeneous mixture.

[0067] (4) Transfer the homogeneous mixed solution from step (3) to a polytetrafluoroethylene-lined reactor, seal it, and place it in a constant temperature drying oven. React at 190°C for 20 hours. After the reaction is complete, allow it to cool naturally to room temperature to obtain a carbonate precursor precipitate.

[0068] (5) The carbonate precursor precipitate mixture from step (4) was filtered with water until neutral, then washed three times with ethanol, and the filter cake was collected and dried in an oven at 70°C for 12 hours to obtain pink precursor powder.

[0069] (6) Weigh 1.5g of precursor powder and 0.8951g of lithium carbonate into a mortar and grind them thoroughly to obtain a uniform mixture.

[0070] (7) The mixture obtained in step (6) is placed into a crucible and then into a muffle furnace. The temperature is increased to 400℃ at 5℃ / min and held for 4 hours. Then the temperature is increased to 800℃ at 5℃ / min and held for 12 hours. After natural cooling, black lithium-rich manganese-based material Li is obtained. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2.

[0071] The prepared lithium-rich manganese-based material was used as a lithium supplement agent and mixed with NCM523 cathode material at an addition amount of 10 wt.% to prepare a cathode sheet.

[0072] The performance test was conducted using the same method as in Example 1.

[0073] Example 4

[0074] (1) Accurately weigh 2.6 g (0.0106 mol) of manganese acetate tetrahydrate, 0.636 g (0.00256 mol) of nickel acetate tetrahydrate, and 0.638 g (0.00256 mol) of cobalt acetate tetrahydrate, dissolve them in 23.4 mL of ethylene glycol, and prepare a mixed acetate solution with a total metal ion concentration of 0.67 mol / L.

[0075] (2) Accurately weigh 1.9g (0.0317mol) of urea and dissolve it in 46.6mL of anhydrous ethanol to prepare a 0.68mol / L urea-ethanol mixed solution.

[0076] (3) Slowly add the urea-ethanol mixture from step (2) to the acetate mixture from step (1), stirring continuously during the addition process. After the addition is complete, continue stirring for 2 hours to obtain a homogeneous mixture.

[0077] (4) Transfer the homogeneous mixed solution from step (3) to a polytetrafluoroethylene-lined reactor, seal it, and place it in a constant temperature drying oven. React at 190°C for 20 hours. After the reaction is complete, allow it to cool naturally to room temperature to obtain a carbonate precursor precipitate.

[0078] (5) The carbonate precursor precipitate mixture from step (4) was filtered with water until neutral, then washed three times with ethanol, and the filter cake was collected and dried in an oven at 70°C for 12 hours to obtain pink precursor powder.

[0079] (6) Weigh 1.5g of precursor powder and 0.8056g of lithium carbonate into a mortar and grind them thoroughly to obtain a uniform mixture.

[0080] (7) The mixture obtained in step (6) is placed into a crucible and then into a muffle furnace. The temperature is increased to 400℃ at 5℃ / min and held for 4 hours. Then the temperature is increased to 850℃ at 5℃ / min and held for 12 hours. After natural cooling, black lithium-rich manganese-based material Li is obtained. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2.

[0081] The prepared lithium-rich manganese-based material was used as a lithium supplement agent and mixed with NCM523 cathode material at an addition amount of 10 wt.% to prepare a cathode sheet.

[0082] The performance test was conducted using the same method as in Example 1.

[0083] Example 5

[0084] (1) Accurately weigh 2.6 g (0.0106 mol) of manganese acetate tetrahydrate, 0.636 g (0.00256 mol) of nickel acetate tetrahydrate, and 0.638 g (0.00256 mol) of cobalt acetate tetrahydrate, dissolve them in 23.4 mL of ethylene glycol, and prepare a mixed acetate solution with a total metal ion concentration of 0.67 mol / L.

[0085] (2) Accurately weigh 1.9g (0.0317mol) of urea and dissolve it in 46.6mL of anhydrous ethanol to prepare a 0.68mol / L urea-ethanol mixed solution.

[0086] (3) Slowly add the urea-ethanol mixture from step (2) to the acetate mixture from step (1), stirring continuously during the addition process. After the addition is complete, continue stirring for 2 hours to obtain a homogeneous mixture.

[0087] (4) Transfer the homogeneous mixed solution from step (3) to a polytetrafluoroethylene-lined reactor, seal it, and place it in a constant temperature drying oven. React at 190°C for 20 hours. After the reaction is complete, allow it to cool naturally to room temperature to obtain a carbonate precursor precipitate.

[0088] (5) The carbonate precursor precipitate mixture from step (4) was filtered with water until neutral, then washed three times with ethanol, and the filter cake was collected and dried in an oven at 70°C for 12 hours to obtain pink precursor powder.

[0089] (6) Weigh 1.5g of precursor powder and 0.8056g of lithium carbonate into a mortar and grind them thoroughly to obtain a uniform mixture.

[0090] (7) The mixture obtained in step (6) is placed into a crucible and then into a muffle furnace. The temperature is increased to 400℃ at 5℃ / min and held for 4 hours. Then the temperature is increased to 800℃ at 5℃ / min and held for 12 hours. After natural cooling, black lithium-rich manganese-based material Li is obtained. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2.

[0091] The prepared lithium-rich manganese-based material was used as a lithium supplement agent and mixed with NCM523 cathode material at an addition amount of 5 wt.% to prepare a cathode sheet.

[0092] The performance test was conducted using the same method as in Example 1.

[0093] Example 6

[0094] (1) Accurately weigh 2.6 g (0.0106 mol) of manganese acetate tetrahydrate, 0.636 g (0.00256 mol) of nickel acetate tetrahydrate, and 0.638 g (0.00256 mol) of cobalt acetate tetrahydrate, dissolve them in 23.4 mL of ethylene glycol, and prepare a mixed acetate solution with a total metal ion concentration of 0.67 mol / L.

[0095] (2) Accurately weigh 1.9g (0.0317mol) of urea and dissolve it in 46.6mL of anhydrous ethanol to prepare a 0.68mol / L urea-ethanol mixed solution.

[0096] (3) Slowly add the urea-ethanol mixture from step (2) to the acetate mixture from step (1), stirring continuously during the addition process. After the addition is complete, continue stirring for 2 hours to obtain a homogeneous mixture.

[0097] (4) Transfer the homogeneous mixed solution from step (3) to a polytetrafluoroethylene-lined reactor, seal it, and place it in a constant temperature drying oven. React at 190°C for 20 hours. After the reaction is complete, allow it to cool naturally to room temperature to obtain a carbonate precursor precipitate.

[0098] (5) The carbonate precursor precipitate mixture from step (4) was filtered with water until neutral, then washed three times with ethanol, and the filter cake was collected and dried in an oven at 70°C for 12 hours to obtain pink precursor powder.

[0099] (6) Weigh 1.5g of precursor powder and 0.8056g of lithium carbonate into a mortar and grind them thoroughly to obtain a uniform mixture.

[0100] (7) The mixture obtained in step (6) is placed into a crucible and then into a muffle furnace. The temperature is increased to 400℃ at 5℃ / min and held for 4 hours. Then the temperature is increased to 800℃ at 5℃ / min and held for 12 hours. After natural cooling, black lithium-rich manganese-based material Li is obtained. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2.

[0101] The prepared lithium-rich manganese-based material was used as a lithium supplement agent and mixed with NCM523 cathode material at an addition amount of 3 wt.% to prepare a cathode sheet.

[0102] The performance test was conducted using the same method as in Example 1.

[0103] Comparative Example 1

[0104] The only difference from Example 1 is the absence of lithium-rich manganese-based material Li. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2.

[0105] The 2025 coin cell was assembled using the method described in Example 1, and the battery cycle performance testing method was the same as in Example 1. Material performance data are shown in Table 2, and the cycle life curves are shown in Table 2. Figure 5 As shown.

[0106] Table 1

[0107]

[0108] Table 2

[0109]

[0110] Figure 5 The figures show the capacity retention curves of the 2025 coin cells prepared in Example 1 and Comparative Example 1 of this invention. It can be seen that the addition of the lithium replenishing agent in this invention significantly improves the initial efficiency and cycle performance of the cells.

[0111] 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 material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 The method for preparing O2 is characterized in that, Includes the following steps: S1. Mix Mn salt, Ni salt, Co salt and urea in a solvent to obtain a mixed solution; S2. React the mixed solution at 180-200℃ for 20-28h, cool, wash, and dry to obtain the carbonate precursor; S3. Grind and mix the carbonate precursor with lithium carbonate to obtain a mixture; S4. The mixture is calcined at 400°C for 4 hours, then calcined at 750-850°C for 10-20 hours, and cooled to obtain the lithium-rich manganese-based material Li. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2; The molar ratio of urea to the total molar ratio of Mn, Ni and Co is 2-3:1; The mass ratio of the carbonate precursor to lithium carbonate is 1:0.4-0.

7.

2. The preparation method according to claim 1, characterized in that, The Mn salt, Ni salt, and Co salt are all acetates.

3. The preparation method according to claim 1, characterized in that, The drying temperature in step S2 is 70-90℃, and the drying time is 10-14h.

4. The preparation method according to claim 1, characterized in that, Step S1 includes the following steps: a. According to the Mn:Ni:Co molar ratio of 0.54:0.13:0.13, Mn salt, Ni salt and Co salt are dissolved in the first solvent to obtain a transition metal solution; urea is dissolved in the second solvent to obtain a urea solution; b. Mix the transition metal solution with the urea solution to obtain the mixed solution.

5. The preparation method according to claim 4, characterized in that, The concentration of the transition metal solution is 0.2-0.8 mol / L; the concentration of the urea solution is 0.5-1.5 mol / L.

6. The preparation method according to claim 4, characterized in that, The first solvent is ethylene glycol, and the second solvent is ethanol.

7. The lithium-rich manganese-based material Li prepared by the preparation method according to any one of claims 1-6 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2.

8. The lithium-rich manganese-based material Li as described in claim 7 1.2 Mn 0.54 Ni 0.13 Co 0.13 Application of O2 as a lithium supplement agent in the positive electrode material of lithium batteries.

9. The application according to claim 8, characterized in that, The positive electrode material of the lithium battery is a ternary material, and the negative electrode material is a silicon-based material.

10. The application according to claim 8, characterized in that, The lithium-rich manganese-based material Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 The amount of O2 added to the cathode material is 3–10 wt.%.

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