WO2019080310A1

WO2019080310A1 - Molybdenum-doped lithium-rich manganese-based cathode material and preparation method therefor

Info

Publication number: WO2019080310A1
Application number: PCT/CN2017/116377
Authority: WO
Inventors: 何苗; 冯叶锋; 王成民; 王润
Original assignee: 广东工业大学
Priority date: 2017-10-23
Filing date: 2017-12-15
Publication date: 2019-05-02
Also published as: CN107768664A

Abstract

A molybdenum-doped lithium-rich manganese-based cathode material, having a chemical formula as shown in formula I: formula I Li 1.2Mn 0.54-xMo xCo 0.13Ni 0.13O 2, wherein 0.05≤x≤0.1. By replacing manganese ions in a layered lithium-rich manganese-based material with metal cations Mo, body phase doping of the layered lithium-rich manganese-based material is realized; and the molybdenum-doped lithium-rich manganese-based cathode material is stable in structure and can effectively inhibit voltage attenuation and capacity fading in a cycle process. Further provided is a preparation method for the molybdenum-doped lithium-rich manganese-based cathode material. By using a sol-gel method for preparation, the structure stability of the obtained layered lithium-rich manganese-based cathode material is improved, and thereby cycle performance is improved and voltage drop generated in the cycle process is inhibited.

Description

Molybdenum doped lithium-rich manganese-based cathode material and preparation method thereof

The present application claims priority to Chinese Patent Application No. 200910992179.7, entitled "A Molybdenum Doped Lithium Manganese Based Cathode Material and Its Preparation Method", filed on October 23, 2017, The entire contents are incorporated herein by reference.

Technical field

The invention belongs to the technical field of lithium ion battery manufacturing, and in particular relates to a molybdenum doped lithium-rich manganese-based cathode material and a preparation method thereof.

Background technique

With the development of society, two major problems facing humanity are environmental pollution and energy crisis. The development of human society is inseparable from non-renewable energy such as coal, oil and natural gas, but these resources will always be consumed. This has led to the development and development of new energy technologies and forms by humans to improve the efficiency of energy use, such as solar energy, geothermal energy and wind energy. However, these new energy technologies are geographically and discontinuous, limiting their use. Therefore, it is necessary to develop corresponding energy storage devices in order to truly achieve continuous supply of energy to meet human energy use needs.

The emergence of lithium-ion batteries has brought hope to the continued use of new energy sources. It has many advantages such as output battery voltage, high energy density, no memory effect, long cycle life, small self-discharge and good safety performance. Lithium-ion batteries include a positive electrode material, an electrolyte, a separator, and a negative electrode material. As one of the key materials of lithium ion batteries, the positive electrode material is directly related to the performance of the battery. Compared with the negative electrode material, the specific capacity of the positive electrode material is relatively low, such as layered LiCoO ₂ and ternary materials, spinel structure LiMn ₂ O ₄ and olivine-type structure LiFePO ₄ and other positive electrode materials have a specific capacity of 200 mAh / Below g, the lithium ion battery is severely hindered from obtaining high energy density, which hinders its further development. However, the layered lithium-rich material has a capacity of more than 250 mAh/g, is inexpensive, is environmentally friendly, and is rich in raw materials, and is suitable for large-scale industrial production. Unfortunately, the layered lithium-rich material has poor rate performance, poor cycle performance and voltage decay during cycling, which seriously hinders its further development.

Summary of the invention

The object of the present invention is to provide a molybdenum-doped lithium-rich manganese-based cathode material and a preparation method thereof, and the molybdenum-doped lithium-rich manganese-based cathode material of the invention has stable structure, good cycle performance and can effectively inhibit the generation of a cyclic process. Pressure drop.

The invention provides a molybdenum-doped lithium-rich manganese-based cathode material having the chemical formula of formula I:

Li _1.2 Mn _0.54-x Mo _x Co _0.13 Ni _0.13 O ₂ Formula I;

Wherein, 0.05≤x≤0.5.

The invention provides a preparation method of a molybdenum-doped lithium-rich manganese-based cathode material, comprising the following steps:

A) dissolving a lithium source, a nickel source, a cobalt source, and a manganese source in water according to a molar ratio in the chemical formula of Formula I to obtain a mixed metal salt solution;

B) sequentially adding an organic acid and a source of molybdenum to the mixed metal salt solution in the step A) to obtain a mixed solution;

C) evaporating the water in the mixed solution in the step B) to obtain a gel material, and drying the gel material to obtain an intermediate;

D) sintering the intermediate in the step C) at 450 to 600 ° C for 5 to 8 hours, and then holding at 750 to 950 ° C for 10 to 24 hours to obtain a molybdenum-doped lithium-rich manganese having the formula I Base cathode material;

Li _1.2 Mn _0.54-x Mo _x Co _0.13 Ni _0.13 O ₂ Formula I;

Wherein, 0.05≤x≤0.5.

Preferably, the lithium source is one or more of lithium hydroxide, lithium carbonate and lithium acetate;

The nickel source is one or more of nickel nitrate, nickel sulfate and nickel acetate;

The cobalt source is one or more of cobalt nitrate, cobalt sulfate and cobalt acetate;

The manganese source is one or more of manganese nitrate, manganese sulfate and manganese acetate.

Preferably, the mixed metal salt solution has a concentration of 0.1 to 3 mol/L.

Preferably, the organic acid is one or more of citric acid, tartaric acid and glycine;

The molar ratio of the organic acid to all transition metal ions in the mixed solution is (1 to 3):1.

Preferably, the molybdenum source is one or more of sodium molybdate, ammonia molybdate and potassium molybdate.

Preferably, the temperature of the evaporation in the step C) is 80 to 120 ° C;

The time of evaporation in the step C) is 10 to 15 hours.

Preferably, the temperature in the step C) is 100 to 150 ° C;

The drying time in the step C) is 10 to 15 hours.

Preferably, the specific process of sintering in the step C) is:

The intermediate in the step B) is raised from room temperature to 450 to 600 ° C at a rate of 1 to 5 ° C / min, sintered for 5 to 8 hours; then raised to 750 ° at a rate of 1 to 5 ° C / min 900 ° C, keep warm for 10 to 24 hours, A molybdenum-doped lithium-rich manganese-based positive electrode material having the formula I is obtained.

The present invention provides a molybdenum-doped lithium-rich manganese-based positive electrode material having the chemical formula of Formula I: Li _1.2 Mn _0.54-x Mo _x Co _0.13 Ni _0.13 O ₂ Formula I; wherein 0.05≤x≤0.5. The invention replaces the manganese ion in the layered lithium-rich manganese-based material by metal cation Mo to realize bulk phase doping of the layered lithium-rich manganese-based material, and the molybdenum-doped lithium-rich manganese-based positive electrode in the invention The material structure is stable and can reduce voltage attenuation and capacity attenuation during the cycle.

The invention also provides a preparation method of a molybdenum-doped lithium-rich manganese-based cathode material, which is prepared by a sol-gel method, and the obtained layered lithium-rich manganese-based cathode material has structural stability, thereby improving cycle performance and suppression. The pressure drop produced by the cycle.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can obtain other drawings according to the provided drawings without any creative work.

1 is an XRD pattern of a molybdenum doped modified layered lithium-rich manganese-based cathode material and a pure phase layered lithium-rich manganese-based cathode material according to Embodiment 1 of the present invention;

2 is an SEM image of a molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.49 Mo _0.05 Co _0.13 Ni _0.13 O ₂ ) in Example 1 of the present invention;

3 is an SEM image of a pure phase layered lithium-rich manganese-based cathode material according to Embodiment 1 of the present invention;

4 is a cycle curve of a layered lithium-rich manganese-based cathode material before and after molybdenum doping in Example 1 of the present invention;

5 is a charge and discharge curve of a test battery made of a molybdenum (Mo) doped modified layered lithium-rich manganese-based positive electrode material in a cycle of 100 cycles according to Embodiment 1 of the present invention;

6 is a graph showing charge and discharge curves of a laboratory battery made of a pure phase layered lithium-rich manganese-based positive electrode material in a cycle of 100 cycles in Example 1 of the present invention.

Detailed ways

Li _1.2 Mn _0.54-x Mo _x Co _0.13 Ni _0.13 O ₂ Formula I;

Wherein, 0.05≤x≤0.5.

In the present invention, the x may be 0.05, 0.1, 0.25, 0.3 or 0.5. The knot having the formula I The positive electrode material is a layered lithium-rich manganese-based positive electrode material doped with molybdenum phase.

The invention also provides a preparation method of a molybdenum-doped lithium-rich manganese-based cathode material, comprising the following steps:

Li _1.2 Mn _0.54-x Mo _x Co _0.13 Ni _0.13 O ₂ Formula I;

Wherein, 0.05≤x≤0.5.

In the present invention, the lithium source, the manganese source, the cobalt source and the nickel source are preferably dissolved in deionized water according to the molar ratio in the formula (I: 1.2:0.54:0.13:0.13), and then the respective solutions are mixed to obtain a mixed metal. Salt solution. In the present invention, the lithium source is one or more of lithium hydroxide, lithium carbonate and lithium acetate; the nickel source is one or more of nickel nitrate, nickel sulfate and nickel acetate; the cobalt source is nitric acid One or more of cobalt, cobalt sulfate and cobalt acetate; the manganese source is one or more of manganese nitrate, manganese sulfate and manganese acetate. The concentration of all metal ions in the mixed metal salt solution is preferably from 0.1 to 3 mol/L, more preferably from 0.5 to 2.5 mol/L, and most preferably from 1 to 2 mol/L. Wherein, the concentration of the lithium source solution is preferably 0.1 to 3 mol/L, more preferably 0.5 to 2.5 mol/L, most preferably 1 to 2 mol/L; and the concentration of the manganese source solution is preferably 0.1 to 3 mol/L. It is preferably 0.5 to 2.5 mol/L, and most preferably 1 to 2 mol/L; the concentration of the solution of the cobalt source is preferably 0.1 to 3 mol/L, more preferably 0.5 to 2.5 mol/L, and most preferably 1 to 2 mol/L. The concentration of the solution of the nickel source is preferably from 0.1 to 3 mol/L, more preferably from 0.5 to 2.5 mol/L, and most preferably from 1 to 2 mol/L.

In the present invention, it is preferred to add an organic acid to the above mixed metal salt solution, and then add a molybdenum source thereto according to a molar ratio in the chemical formula of the formula I, and stir for 1 to 2 hours to obtain a mixed solution. The organic acid is preferably one or more of citric acid, tartaric acid and glycine; the molar ratio of the organic acid to all transition metals in the mixed metal salt solution is preferably (1 to 3): 1, more preferably It is 2:1. Said The molybdenum source is preferably one or more of sodium molybdate, ammonia molybdate, and potassium molybdate.

In the present invention, the temperature of the evaporation is preferably 80 to 120 ° C, more preferably 90 to 110 ° C, most preferably 100 ° C; and the evaporation time is preferably 10 to 15 hours, more preferably 11 to 14 hours, most preferably 12 to 13 hours. In the present invention, it is preferred to carry out the above-described evaporation under stirring. After all of the deionized water was evaporated to dryness, a gel material was obtained.

The gel material is then dried, preferably at a temperature of from 100 to 150 ° C, more preferably from 110 to 140 ° C, most preferably from 120 to 130 ° C; and the drying time is preferably from 10 to 15 hours, more It is preferably 11 to 14 hours, and most preferably 12 to 13 hours. After obtaining a dried product, the present invention is subjected to ball milling and pulverization to obtain an intermediate.

The invention sinters the above intermediate, and the specific process of the sintering is:

The intermediate in the step B) is raised from room temperature to 450 to 600 ° C at a rate of 1 to 5 ° C / min, preferably 500 to 550 ° C, and sintered for 5 to 8 hours, preferably 6 to 7 hours; Increasing to 750-900 ° C, preferably 800-850 ° C at a rate of 1 ~ 5 ° C / min, holding for 10 ~ 24 hours, preferably 12 ~ 20 hours, after natural cooling after sintering, to obtain a molybdenum of formula I Doped lithium-rich manganese-based cathode material.

In order to further illustrate the present invention, a molybdenum-doped lithium-rich manganese-based positive electrode material provided by the present invention and a method for preparing the same are described in detail below with reference to the embodiments, but are not to be construed as limiting the scope of the present invention.

Example 1

According to the chemical formula shown in the layered lithium-rich manganese-based cathode material, the molar ratio is 1.2:0.54:0.13:0.13, and a certain amount of lithium salt, nickel salt, drill salt and manganese salt are dissolved in deionized water to prepare a concentration of 0.1 mol. An aqueous solution of /L and the above solution is mixed.

Citric acid was added to the above mixed solution in an amount of 1:1 by mole ratio of all transition metal ions to organic acid in the mixed solution.

Ammonium molybdate was added to the above mixed solution in an amount of x=0.05, and the mixture was stirred for 1 hour.

The mixed solution obtained above was stirred at 80 ° C for 10 hours until all of the deionized water was evaporated to dryness to obtain a gel material, which was then dried in a dry box at 100 ° C for 10 hours, and then the dried product was taken out for ball milling.

Finally, the crushed powder material was sintered in an air atmosphere at 25 ° C from 1 ° C / min to 450 ° C for 8 h, and then incubated at 1 ° C / min to 750 ° C for 24 h in an air atmosphere, and naturally cooled to room temperature to obtain molybdenum ( Mo) doped modified layered lithium-rich manganese-based positive electrode material (Li _1.2 Mn _0.49 Mo _0.05 Co _0.13 Ni _0.13 O ₂ ).

The molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.49 Mo _0.05 Co _0.13 Ni _0.13 O ₂ ) obtained in Example 1 and the pure phase layered lithium-rich manganese obtained in Example 1 The base cathode material was subjected to XRD analysis and SEM analysis. 1 to 3, FIG. 1 is an XRD pattern of (A) molybdenum doped modified layered lithium-rich manganese-based cathode material and (B) pure phase layered lithium-rich manganese-based cathode material in Example 1 of the present invention. . It is known from the XRD pattern that the molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material is consistent with the diffraction peak of the layered lithium-rich material before modification, indicating that molybdenum (Mo) doping does not change the layered lithium-rich material. Phase structure of manganese-based cathode material. 2 is an SEM image of a molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.49 Mo _0.05 Co _0.13 Ni _0.13 O ₂ ) in Example 1 of the present invention, and FIG. 3 is an embodiment of the present invention. SEM image of a pure phase layered lithium-rich manganese-based cathode material in 1. It can be seen from the comparison of Fig. 2 and Fig. 3 that the microstructure of the material does not change after molybdenum (Mo) doping.

The prepared molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.49 Mo _0.05 Co _0.13 Ni _0.13 O ₂ ) and conductive carbon black were prepared according to the ratio of 8:1:1 in Example 1: SuperP, binder PVDF was added to N-methylpyrrolidone for stirring and mixing, and the resulting slurry was coated on an aluminum foil and dried at 120 ° C for 12 hours to obtain a positive electrode sheet. The battery was assembled in an argon-filled glove box, the negative electrode was a lithium metal plate, the separator was polypropylene, and LiPF ₆ was an electrolyte. The obtained battery was subjected to a charge and discharge test at a magnification of 1 C, and the obtained cycle curve is shown in FIG. 4 is a cycle curve of a layered lithium-rich manganese-based cathode material before and after molybdenum doping in Example 1 of the present invention.

A and B in Fig. 4 are cycle curves of the molybdenum (Mo) doped modified and pure layered lithium rich materials obtained in Example 1, respectively. 4A, the first discharge specific capacity of the molybdenum (Mo) doped layered lithium-rich material prepared in Example 1 was 183.2 mAh/g, and the capacity retention rate reached 98.3% after 100 cycles, but pure. The layered lithium-rich material has a capacity retention rate of only 45% after 100 cycles. Through the map 5 and Figure 6 can be seen that molybdenum (Mo) doping can effectively suppress voltage decay during cycling. It can be seen from the above results that the molybdenum (Mo) doping modification can effectively improve the material cycle stability, and stabilize the material structure to suppress voltage attenuation.

Example 2

A certain amount of lithium salt, nickel salt, drill salt and manganese salt are weighed and dissolved in deionized water according to the molar ratio shown in the chemical formula of the layered lithium-rich manganese-based positive electrode material, and are prepared into an aqueous solution having a concentration of 1.5 mol/L, and the above The solution was mixed.

Tartaric acid was added to the above mixed solution in an amount of 1:1.5 in a molar ratio of all transition metal ions to organic acid in the mixed solution.

Sodium molybdate was added to the above mixed solution in an amount of x=0.1, and the mixture was stirred for 1.5 hours.

The mixed solution obtained above was stirred at 90 ° C for 12 hours until all of the deionized water was evaporated to dryness to obtain a gel material, which was then dried in a dry box at 120 ° C for 11 hours, and then the dried product was taken out for ball milling.

Finally, the crushed powder material was sintered in an air atmosphere at 25 ° C to 500 ° C for 2 h at 2 ° C / min, and then raised to 800 ° C for 2 h in an air atmosphere at 2 ° C / min, and naturally cooled to room temperature to obtain molybdenum ( Mo) doped modified layered lithium-rich manganese-based positive electrode material (Li _1.2 Mn _0.44 Mo _0.1 Co _0.13 Ni _0.13 O ₂ ).

Electrochemical performance analysis of the molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material obtained in Example 2: 0.8 g of molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.44 Mo _0.1 Co _0.13 Ni _0.13 O ₂ ), 0.05 g of acetylene black and 0.05 g of PVDF, 0.4 g of NMP was added and dispersed, and the obtained slurry was coated on an aluminum foil, and dried in an anaerobic glove box with metallic lithium. The film is a counter electrode and assembled into a CR2025 button battery. At 25 ° C, the 1C rate was tested for 100 charge-discharge cycles between 2-4.8 V. The results showed that the molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.54-x Mo _x Co _0.13 Ni _0.13 O ₂ ) has a high specific capacity, is stable in circulation, and can effectively suppress voltage fluctuation of material structure change, and exhibits excellent electrochemical performance.

Example 3

According to the molar ratio of all transition metal ions to organic acid in the mixed solution, the ratio of glycine is 1:2. It is added to the above mixed solution.

A source of sodium molybdate was added to the above mixed solution in an amount of x=0.25, and the mixture was stirred for 1.5 hours.

The mixed solution obtained above was stirred at 100 ° C for 13 hours until all of the deionized water was evaporated to dryness to obtain a gel material, which was then dried in a dry box at 125 ° C for 13 hours, and then the dried product was taken out for ball milling.

Finally, the crushed powder material was sintered from 25 ° C to 525 ° C in air atmosphere at 5 ° C / min for 5-8 h, then raised to 850 ° C in air at 3 ° C / min for 17 h, and naturally cooled to room temperature. Molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.29 Mo _0.25 Co _0.13 Ni _0.13 O ₂ ).

Electrochemical performance analysis of the molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material obtained in Example 3: 0.8 g of molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.29 Mo _0.25 Co _0.13 Ni _0.13 O ₂ ), 0.05 g acetylene black and 0.05 g PVDF, 0.4 g of NMP was mixed and dispersed, and the obtained slurry was coated on an aluminum foil, and dried in an anaerobic glove box with metallic lithium. The film is a counter electrode and assembled into a CR2025 button battery. At 25 °C, the 1C rate was tested at 100 times charge-discharge cycle between 2-4.8V. The results show that the molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material has high specific capacity, stable cycle, and Effectively suppressing material structure changes produces voltage attenuation and exhibits excellent electrochemical performance.

Example 4

A certain amount of lithium salt, nickel salt, drill salt and manganese salt are weighed in deionized water according to the molar ratio shown in the chemical formula of the layered lithium-rich manganese-based positive electrode material, and are prepared into an aqueous solution having a concentration of 2 mol/L, and the above solution is prepared. Mix.

Citric acid was added to the above mixed solution in an amount of 1:1.3 in a molar ratio of all transition metal ions to organic acid in the mixed solution.

Ammonium molybdate was added to the above mixed solution in an amount of x=0.3, and the mixture was stirred for 1.2 hours.

The mixed solution obtained above was stirred at 110 ° C for 14 hours until all of the deionized water was evaporated to dryness to obtain a gel material, which was then dried in a dry box at 140 ° C for 11 hours, and then the dried material was taken out for ball milling.

Finally, the crushed powder material was sintered in the air atmosphere from 25 ° C to 500 ° C for 7 h in 4 ° C / min, then raised to 900 ° C in air at 4 ° C / min for 15 h, and naturally cooled to room temperature to obtain molybdenum ( Mo) doped modified layered lithium-rich manganese-based positive electrode material (Li _1.2 Mn _0.24 Mo _0.3 Co _0.13 Ni _0.13 O ₂ ).

Electrochemical performance analysis of the molybdenum doped modified layered lithium-rich manganese-based cathode material obtained in Example 4: 0.8 g of molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.24) Mo _0.3 Co _0.13 Ni _0.13 O ₂ ), 0.05 g of acetylene black and 0.05 g of PVDF, 0.4 g of NMP was mixed and dispersed, and the obtained slurry was coated on an aluminum foil, and dried in an anaerobic glove box with a metal lithium plate as a pair. The electrodes are assembled into a CR2025 button battery. At 25 ° C, the 1C rate was tested at 100 times charge-discharge cycle between 2-4.8V. The results show that the molybdenum (Mo) doped layered lithium-rich manganese-based cathode material has high specific capacity, stable cycle, and can be effective. Suppressing material structure changes produces voltage decay and exhibits excellent electrochemical performance.

Example 5

A certain amount of lithium salt, nickel salt, drill salt and manganese salt are weighed in deionized water according to the molar ratio shown in the chemical formula of the layered lithium-rich manganese-based positive electrode material, and are prepared into an aqueous solution having a concentration of 3 mol/L, and the above solution is prepared. Mix.

Tartaric acid was added to the above mixed solution in an amount of 1:3 by mole of all transition metal ions to organic acid in the mixed solution.

Ammonium molybdate was added to the above mixed solution in an amount of molybdenum doping amount of x = 0.5, and stirring was carried out for 2 hours.

The mixed solution obtained above was stirred at 120 ° C for 15 h until all of the deionized water was evaporated to dryness to obtain a gel material, which was then dried in a dry box at 150 ° C for 10 h, and then the dried material was taken out for ball milling.

Finally, the crushed powder material was sintered from 25 ° C to 600 ° C for 5 h in an air atmosphere at 5 ° C / min, and then incubated at 5 ° C / min to 950 ° C for 10 h in an air atmosphere, and naturally cooled to room temperature to obtain molybdenum ( Mo) doped modified layered lithium-rich manganese-based positive electrode material (Li _1.2 Mn _0.04 Mo _0.5 Co _0.13 Ni _0.13 O ₂ ).

Electrochemical performance analysis of the molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material obtained in Example 5: 0.8 g of molybdenum (Mo) doped modified layered lithium-rich manganese-based cathode material (Li _1.2 Mn _0.04 Mo _0.5 Co _0.13 Ni _0.13 O ₂ ), 0.05 g acetylene black and 0.05 g PVDF, 0.4 g of NMP was mixed and dispersed, and the obtained slurry was coated on an aluminum foil, and dried in an anaerobic glove box with metallic lithium. The film is a counter electrode and assembled into a CR2025 button battery. At 25 ° C, the 1C rate was tested at 100 times charge-discharge cycle between 2-4.8V. The results show that the molybdenum (Mo) doped layered lithium-rich manganese-based cathode material has high specific capacity, stable cycle, and can be effective. Suppressing material structure changes produces voltage decay and exhibits excellent electrochemical performance.

The above description is only a preferred embodiment of the present invention, and it should be noted that it is common to the art. The skilled person will be able to make several modifications and refinements without departing from the principles of the invention, and such modifications and refinements are also considered to be within the scope of the invention.

Claims

A molybdenum-doped lithium-rich manganese-based cathode material having the chemical formula of formula I:

Li 1.2 Mn 0.54-x Mo x Co 0.13 Ni 0.13 O 2 Formula I;

Wherein, 0.05≤x≤0.5.
A method for preparing a molybdenum-doped lithium-rich manganese-based cathode material comprises the following steps:

A) dissolving a lithium source, a nickel source, a cobalt source, and a manganese source in water according to a molar ratio in the chemical formula of Formula I to obtain a mixed metal salt solution;

B) sequentially adding an organic acid and a source of molybdenum to the mixed metal salt solution in the step A) to obtain a mixed solution;

C) evaporating the water in the mixed solution in the step B) to obtain a gel material, and drying the gel material to obtain an intermediate;

D) sintering the intermediate in the step C) at 450 to 600 ° C for 5 to 8 hours, and then holding at 750 to 950 ° C for 10 to 24 hours to obtain a molybdenum-doped lithium-rich manganese having the formula I Base cathode material;

Li 1.2 Mn 0.54-x Mo x Co 0.13 Ni 0.13 O 2 Formula I;

Wherein, 0.05≤x≤0.5.
The preparation method according to claim 2, wherein the lithium source is one or more of lithium hydroxide, lithium carbonate and lithium acetate;

The nickel source is one or more of nickel nitrate, nickel sulfate and nickel acetate;

The cobalt source is one or more of cobalt nitrate, cobalt sulfate and cobalt acetate;

The manganese source is one or more of manganese nitrate, manganese sulfate and manganese acetate.
The method according to claim 2, wherein the mixed metal salt solution has a concentration of 0.1 to 3 mol/L.
The preparation method according to claim 2, wherein the organic acid is one or more of citric acid, tartaric acid and glycine;

The molar ratio of the organic acid to all transition metal ions in the mixed solution is (1 to 3):1.
The method according to claim 2, wherein the molybdenum source is one or more of sodium molybdate, ammonia molybdate, and potassium molybdate.
The preparation method according to claim 2, wherein the temperature in the step C) is 80 to 120 ° C;

The time of evaporation in the step C) is 10 to 15 hours.
The preparation method according to claim 2, wherein the drying temperature in the step C) is 100 to 150 ° C;

The drying time in the step C) is 10 to 15 hours.
The preparation method according to claim 2, wherein the specific process of sintering in the step C) is:

The intermediate in the step B) is raised from room temperature to 450 to 600 ° C at a rate of 1 to 5 ° C / min, sintered for 5 to 8 hours; then raised to 750 ° at a rate of 1 to 5 ° C / min The lithium-doped lithium-rich manganese-based positive electrode material having the chemical formula of Formula I is obtained by holding at 900 ° C for 10 to 24 hours.