CN117096336A - Manganese-based layered oxide positive electrode material, preparation method thereof, positive electrode sheet and secondary battery - Google Patents

Manganese-based layered oxide positive electrode material, preparation method thereof, positive electrode sheet and secondary battery Download PDF

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CN117096336A
CN117096336A CN202311202747.0A CN202311202747A CN117096336A CN 117096336 A CN117096336 A CN 117096336A CN 202311202747 A CN202311202747 A CN 202311202747A CN 117096336 A CN117096336 A CN 117096336A
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manganese
based layered
layered oxide
positive electrode
sodium
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陈逊杰
李诗文
农廷峰
谢思思
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Gaodian Shenzhen Technology Co ltd
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Gaodian Shenzhen Technology Co ltd
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    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
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    • C01G45/1221—Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof
    • C01G45/1228—Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof of the type [MnO2]n-, e.g. LiMnO2, Li[MxMn1-x]O2
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    • C01G51/50—Cobaltates containing alkali metals, e.g. LiCoO2 containing manganese of the type [MnO2]n-, e.g. Li(CoxMn1-x)O2, Li(MyCoxMn1-x-y)O2
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    • C01G53/44—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Nickelates containing alkali metals, e.g. LiNiO2 containing manganese of the type [MnO2]n-, e.g. Li(NixMn1-x)O2, Li(MyNixMn1-x-y)O2
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    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
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    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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    • H01M2004/028—Positive electrodes
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    • Y02E60/10—Energy storage using batteries

Abstract

The invention provides a manganese-based layered oxide positive electrode material, a preparation method thereof, a positive electrode plate and a secondary battery, wherein the positive electrode material comprises 10-20% of Na element, 30-45% of Mn element, 1-25% of doped metal element Me and the balance of oxygen, and the 2 theta diffraction angle of the positive electrode material has the following characteristic peaks under the XRD spectrum of a copper target K alpha 1: 15.8-16.2 °, 31.9-32.3 °, 35.7-36.1 °, 39.2-39.6 °, 43.3-43.7 °, 48.7-49.1 °, 62.1-62.5 °, 64.3-64.7 °, 66.6-67 °, and 66.9-67.3 °. The manganese-based layered oxide positive electrode material has higher specific discharge capacity and a working platform.

Description

Manganese-based layered oxide positive electrode material, preparation method thereof, positive electrode sheet and secondary battery
Technical Field
The invention relates to the field of secondary batteries, in particular to a manganese-based layered oxide positive electrode material, a preparation method thereof, a positive electrode plate and a secondary battery.
Background
The lithium ion battery has the advantages of poor energy density, light weight, long cycle life and the like, and is widely applied to various fields of traffic, energy storage and consumption at present. However, reserves of lithium resources on earth are relatively scarce and unevenly distributed. Therefore, the development of a new generation secondary battery is of great importance to the national energy storage strategy layout. Among them, sodium ion batteries are considered to be a new secondary battery that is the most promising alternative to lithium ion batteries because of their abundant and widely distributed metal sodium resources and low cost. The sodium ion battery has an energy storage mechanism similar to that of a lithium ion battery, and belongs to a rocking chair type battery, namely, reversible intercalation and deintercalation between an anode and a cathode are realized by means of charged metal ions (Na+/Li+), so that the conversion between chemical energy and electric energy is realized. Currently, positive electrode materials capable of achieving stable removal/intercalation of sodium ions are major obstacles limiting the application of sodium ion batteries.
Sodium ion positive electrode materials are mainly classified into three categories, namely layered oxides, phosphoric acid compounds and Prussian blue analogues. The layered oxide has high theoretical capacity, simple preparation mode and controllable property, and is widely studied. Although most layered oxides have a higher theoretical capacity, their voltage plateau is lower.
Patent number CN 115924978A describes the preparation and application of a manganese-based layered sodium-ion battery positive electrode material having the chemical formula Na y Mn 1-x M x O 2 The method comprises the steps of carrying out a first treatment on the surface of the Wherein 0.6<y<1，0<x<0.5; m includes at least one of Zn, al, mg, fe and Cu. The sample had a specific discharge capacity of 193mAh/g at 2.0V to 4.6V and 0.1C, whereas the capacity of 3.0V or more was only 41.5%.
Disclosure of Invention
One of the objects of the present invention is: aiming at the defects of the prior art, the manganese-based layered oxide anode material is provided, and has higher voltage platform and discharge specific capacity.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the manganese-based layered oxide positive electrode material comprises 10-20% of Na element, 30-45% of Mn element, 1-25% of doped metal element Me and at least one of the doped metal elements Me and Ni, fe, mg, co, cu, ti, wherein the balance is oxygen; the 2 theta diffraction angle of the manganese-based layered oxide positive electrode material has the following characteristic peaks under the XRD spectrum of a copper target K alpha 1: 15.8-16.2 °, 31.9-32.3 °, 35.7-36.1 °, 39.2-39.6 °, 43.3-43.7 °, 48.7-49.1 °, 62.1-62.5 °, 64.3-64.7 °, 66.6-67 °, and 66.9-67.3 °.
The chemical formula Na of the manganese-based layered oxide positive electrode material of the invention 0.5+x Mn y Me 1-y O 2 (x≥0，0<y<1) The positive electrode material containing a certain chemical element composition is arranged, so that the positive electrode material has good specific discharge capacity, a higher working platform and higher output power. The charging curve of the sodium ion battery provided by the invention under the voltage interval of 2.0-4.35V and the current density of 0.1C is provided with at least two charging and discharging platforms, namely, the manganese-based layered oxide positive electrode material is converted from P2 phase to O2 phase. Meanwhile, the sodium ion battery has a specific discharge capacity of 120 mAh/g-160 mAh/g in a voltage interval of 2.0-4.35V and a current density of 0.1C, so that the overall energy efficiency is relatively high. From the above characteristic peaks, it is apparent that the manganese-based layered oxide positive electrode material of the present invention has a P2 phaseStructure is as follows.
Wherein the manganese-based layered oxide positive electrode material has a single crystal morphology of 2-6 mu m. Specifically, the manganese-based layered oxide cathode material may have a single crystal morphology of 2 μm, 3 μm, 4 μm, 5 μm, 6 μm. The manganese-based layered oxide positive electrode material with the single crystal morphology has a stable structure and good electrochemical performance. The manganese-based layered oxide with single crystal morphology is set as certain particles, so that the positive electrode material has certain compaction density.
The second purpose of the invention is to provide a preparation method of the manganese-based layered oxide positive electrode material, which adopts a liquid phase method to prepare the manganese-based layered oxide positive electrode material, so that the elements are mixed more uniformly, and the prepared manganese-based layered oxide positive electrode material has a more stable structure.
The preparation method of the manganese-based layered oxide cathode material comprises the following steps:
s1, dissolving a sodium source, a manganese source and a doped metal source in a solvent to obtain a precursor mixed solution;
s2, transferring the precursor mixed solution into a hydrothermal kettle for precipitation reaction, filtering, washing and drying the precipitate to obtain a precursor;
and step S3, placing the precursor in a muffle furnace for sintering to obtain the manganese-based layered oxide cathode material.
According to the invention, liquid phase mixing is adopted, so that the mixing uniformity and consistency of each element can be improved, a precursor with good mixing property is obtained, and then the precursor is placed in a muffle furnace for sintering, so that the manganese-based layered oxide positive electrode material with stable uniformity structure is obtained.
Wherein, in the step S1, the mass part ratio of the sodium source, the manganese source and the doped metal source is 1-30: 2-20: 1 to 20.
Wherein the sodium source is one or more than two of sodium nitrate, sodium carbonate, sodium bicarbonate and sodium hydroxide; the manganese source is one or a mixture of more than two of manganese nitrate, manganese acetate, manganese sulfate and manganese chloride; the doped metal source is one or more than two of carbonate, acetate, chloride and sulfate.
Wherein the solvent in the step S1 is one or more than two of water, isopropanol, ethanol and methanol.
Wherein the temperature of the precipitation reaction in the step S2 is 120-160 ℃, and the reaction time is 6-10 h. The precipitation reaction temperature can be 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃ and the reaction time can be 6 hours, 7 hours, 8 hours, 9 hours and 10 hours.
Wherein the sintering temperature in the step S3 is 700-1000 ℃ and the sintering time is 6-12 h. Specifically, the sintering temperature may be 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, 980 ℃, 1000 ℃ and the sintering time may be 6h, 7h, 8h, 9h, 10h, 11h, 12h.
The third object of the present invention is to provide a positive electrode sheet having excellent electrochemical performance and cycle performance.
The positive electrode sheet comprises the manganese-based layered oxide positive electrode material. Specifically, the positive plate comprises a positive current collector and a positive active coating arranged on the surface of the positive current collector, wherein the positive active coating comprises a manganese-based layered oxide positive electrode material.
The fourth object of the present invention is to provide a secondary battery having a good service life and safety performance.
A secondary battery comprises the positive plate. Specifically, the secondary battery comprises a negative plate, a separation membrane, electrolyte, a shell and the positive plate, wherein the separation membrane is used for separating the negative plate from the positive plate, and the shell is used for mounting and packaging the negative plate, the separation membrane, the positive plate and the electrolyte.
The secondary battery has at least two charge and discharge platforms in the charge and discharge curve of 2.0-4.35V and 0.1C current density.
Wherein the capacity ratio of the secondary battery under the voltage interval of 4.0-4.35V and the current density of 0.1C is 30-50%; the capacity ratio under the voltage interval of 3.0-4.0V and the current density of 0.1C is 40-60 percent; the capacity ratio is 1-20% under the voltage interval of 2.0-3.0V and the current density of 0.1C.
Compared with the prior art, the invention has the beneficial effects that: the manganese-based layered oxide anode material has higher specific discharge capacity, a working platform and higher output power.
Drawings
Fig. 1 is an XRD pattern of the manganese-based layered oxide cathode materials of examples 1 to 5.
Fig. 2 is an SEM image of the manganese-based layered oxide cathode material of the present example 1.
Fig. 3 is an SEM image of the manganese-based layered oxide cathode material of this example 3.
Fig. 4 is a first charge-discharge graph of the present example 1.
Fig. 5 is a first charge-discharge graph of this example 2.
Fig. 6 is a first charge-discharge graph of this example 3.
Detailed Description
In order to make the technical solution and advantages of the present invention more apparent, the present invention and its advantageous effects will be described in further detail below with reference to the specific embodiments, but the embodiments of the present invention are not limited thereto.
Example 1
The manganese-based layered oxide positive electrode material comprises 14.8% of Na, 31.7% of Mn and 22.6% of Ni elements by mass, and the preparation method comprises the following steps:
respectively weighing sodium nitrate, manganese nitrate and nickel nitrate, dissolving the sodium nitrate, the manganese nitrate and the nickel nitrate in a mixed solution of water and ethanol (the volume ratio is 1:1) to obtain a precursor mixed solution;
transferring the precursor mixed solution into a hydrothermal kettle, reacting for 8 hours at 150 ℃, filtering, washing and drying the precipitate to obtain a precursor;
step (3), placing the precursor in a muffle furnace, heating to 900 ℃ at normal temperature, preserving heat for 10 hours, naturally cooling to room temperature, and grinding to obtain the manganese-based layered oxide with a chemical formula of Na 0.67 Mn 0.6 Ni 0.4 O 2 . Wherein, the mass ratio of Na, mn and Ni elements is 14.8%, 31.7% and 22.6% respectively.
X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) tests are carried out on the manganese-based layered oxide sodium ion battery anode material, and specific test results are shown in fig. 1 and 2.
XRD results show that the sample has a P2 type layered structure and complete structure, and no other impurity phase exists; according to SEM results, the appearance of the sample is amorphous, the surface is smooth, and the size is 2-4 mu m.
Specifically, the manufacturing process of the sodium ion battery comprises the following steps: the manganese-based layered oxide, a conductive agent and a binder are mixed according to the mass ratio of 8:1:1, adding N-methyl pyrrolidone for pulping and coating on an aluminum foil, drying, and then forming a punching sheet by a punching machine to obtain the positive plate. And assembling the obtained positive plate, metal sodium and a diaphragm into a battery, injecting electrolyte, and standing for 12 hours to test the electrical property.
The first charge-discharge curve graph of the positive electrode material of the sodium ion battery after assembly and buckling is shown in fig. 4, has a reversible specific capacity of 140mAh/g at a current density of 0.1C, and has an average working voltage of 3.65V. Notably, three distinct pairs of voltage plateaus, 3.28/3.11V, 3.65/3.60V and 4.20/4.10V, respectively, occur during both charge and discharge, representing a reversible transition of the structure through the P2-O2 configuration. Wherein, the capacity of 4.0-4.35V is 40 percent; 3.0 to 4.0V of 55.7 percent; the capacity ratio of 2.0-3.0V is 4.3%.
Example 2
The manganese-based layered oxide sodium ion battery anode material comprises 17.2% of Na, 30.9% of Mn and 22.0% of Ni elements by mass, and the preparation method comprises the following steps:
sodium nitrate, manganese nitrate and nickel nitrate are respectively weighed and prepared according to the method of the steps (1) - (3) in the embodiment 1, wherein the mass ratio of Na, mn and Ni elements of the manganese-based layered oxide is 17.2%, 30.9% and 22.0% respectively.
The positive electrode material of the sodium ion battery has a P2 layered structure similar to that of example 1 and has no other impurity phase, as shown in fig. 1.
The manganese-based layered oxide obtained in example 2 was used as a positive electrode active material and assembled with a metallic sodium negative electrode to form a sodium ion battery, and the assembly method was the same as that of example 1, and will not be repeated. The first charge-discharge curve of the positive electrode material is shown in fig. 5. From the graph, it can be found that the increase of sodium content in the structure has a significant effect on the increase of specific discharge capacity, wherein the capacity ratio of 4.0-4.35V is 36.2%;3.0-4.0V of 50.2%; the capacity ratio of 2.0 to 3.0V is 13.6%, and thus, an increase in Na content can be used for capacity improvement of 3.0V or less.
Example 3
The manganese-based layered oxide sodium ion battery anode material comprises 14.8% of Na, mn, ni, co elements, 31.7% of the manganese-based layered oxide sodium ion battery anode material, 17.0% of the manganese-based layered oxide sodium ion battery anode material and 5.7% of the manganese-based layered oxide sodium ion battery anode material, wherein the preparation method comprises the following steps:
sodium nitrate, manganese nitrate, nickel nitrate and cobalt nitrate are respectively weighed and prepared according to the method of the steps (1) - (3) in the embodiment 1, wherein the mass ratio of Na, mn, ni, co elements of the manganese-based layered oxide is 14.8%, 31.7%, 17.0% and 5.7% respectively.
The positive electrode material of the sodium ion battery has a P2 layered structure similar to that of the embodiment 1 and has no other impurity phases, as shown in fig. 1; the SEM results according to FIG. 3 show that the sample morphology is amorphous and smooth, with dimensions of 2-4. Mu.m.
The manganese-based layered oxide obtained in example 3 was used as a positive electrode active material and assembled with a metallic sodium negative electrode to form a sodium ion battery, and the assembly method was the same as that of example 1, and will not be repeated. The first charge-discharge curve of the positive electrode material is shown in fig. 6. It can be found from the graph that the introduction of Co element can significantly raise the charge-discharge plateau voltage of the material, and compared with the embodiment 1, each plateau voltage is raised by 0.5-1.0V, which has an important supporting effect on the design of the high-energy-density sodium ion battery. Wherein, the capacity ratio of 4.0-4.35V is 38.1 percent; the capacity ratio of 3.0-4.0V is 46.5%; the capacity ratio of 2.0-3.0V is 15.4%.
Example 4
The manganese-based layered oxide sodium ion battery anode material comprises 14.8% of Na, mn, ni, cu elements, 31.7% of the manganese-based layered oxide sodium ion battery anode material, 17.0% of the manganese-based layered oxide sodium ion battery anode material and 6.1% of the manganese-based layered oxide sodium ion battery anode material, wherein the preparation method comprises the following steps:
sodium nitrate, manganese nitrate, nickel nitrate and copper nitrate are respectively weighed and prepared according to the method of the steps (1) - (3) in the embodiment 1, wherein the mass ratio of Na, mn, ni, cu elements of the manganese-based layered oxide is 14.8%, 31.7%, 17.0% and 6.1% respectively.
The positive electrode material of the sodium ion battery has a P2 layered structure similar to that of example 1 and has no other impurity phase, as shown in fig. 1.
The manganese-based layered oxide obtained in example 4 was used as a positive electrode active material and assembled with a metallic sodium negative electrode to form a sodium ion battery, and the assembly method was the same as that of example 1, and will not be repeated. The capacity ratio of each potential interval of the positive electrode material is shown in table 1.
Example 5
The manganese-based layered oxide sodium ion battery anode material comprises 14.8% of Na, mn, ni, mg elements, 31.7% of the manganese-based layered oxide sodium ion battery anode material, 17.0% of the manganese-based layered oxide sodium ion battery anode material and 4.6% of the manganese-based layered oxide sodium ion battery anode material, wherein the preparation method comprises the following steps:
sodium nitrate, manganese nitrate, nickel nitrate and magnesium nitrate are respectively weighed and prepared according to the method of the steps (1) - (3) in the example 1, wherein the mass ratio of Na, mn, ni, mg elements of the manganese-based layered oxide is 14.8%, 31.7%, 17.0% and 2.4% respectively.
The positive electrode material of the sodium ion battery has a P2 layered structure similar to that of example 1 and has no other impurity phase, as shown in fig. 1.
The manganese-based layered oxide obtained in example 5 was used as a positive electrode active material and assembled with a metallic sodium negative electrode to form a sodium ion battery, and the assembly method was the same as that of example 1, and will not be repeated. The capacity ratio of each potential interval of the positive electrode material is shown in table 1.
Example 6
Unlike example 1, the following is: and in the step S3, placing the precursor in a muffle furnace, and sintering for 10 hours at 700 ℃ to obtain the manganese-based layered oxide cathode material.
The remainder is the same as embodiment 1 and will not be described here again.
Example 7
Unlike example 1, the following is: and in the step S3, placing the precursor in a muffle furnace, and sintering for 10 hours at 800 ℃ to obtain the manganese-based layered oxide cathode material.
The remainder is the same as embodiment 1 and will not be described here again.
Example 8
Unlike example 1, the following is: and in the step S3, placing the precursor in a muffle furnace, and sintering for 10 hours at 1000 ℃ to obtain the manganese-based layered oxide cathode material.
The remainder is the same as embodiment 1 and will not be described here again.
Example 9
Unlike example 1, the following is: and in the step S3, placing the precursor in a muffle furnace, and sintering for 8 hours at 900 ℃ to obtain the manganese-based layered oxide cathode material.
The remainder is the same as embodiment 1 and will not be described here again.
Example 10
Unlike example 1, the following is: and in the step S3, placing the precursor in a muffle furnace, and sintering for 12h at 900 ℃ to obtain the manganese-based layered oxide cathode material.
The remainder is the same as embodiment 1 and will not be described here again.
Comparative example 1
The preparation method of the manganese-based layered sodium ion battery anode material provided by the embodiment comprises the following steps:
(1) According to the mole ratio Na: mn: mg=0.67: 0.8:0.2 weighing Na 2 CO 3 (sodium Source), mn 3 O 4 (manganese source) and MgO (M element-containing compound, wherein M is Mg), then adding the mixture into deionized water, and performing wet ball milling in a ball mill to obtain uniformly mixed ball milling slurry. Wherein, the adding amount of deionized water is weighed according to the solid content of the slurry of wet ball milling being 20 percent. The stirring frequency of wet ball milling is 35Hz, and the time of wet ball milling is 2h. The molar ratio Na: mn: mg means a molar ratio of sodium element in a sodium source, manganese element in a manganese source, and M element in a compound containing M element, and each of the following examples and each of the comparative examples are the same.
(2) Transferring the ball milling slurry obtained in the step (1) into a sand mill for sand milling to obtain D 50 Sand abrasive with particle size of 0.24 μm. Wherein, the rotational speed of sanding is 1200rpm, and the time of sanding is 2h.
(3) And (3) spray drying the sand grinding material obtained in the step (2) to obtain uniform powder (light brown) of particles. Wherein, the air inlet temperature of spray drying is 260 ℃, the air outlet temperature is 95 ℃, and the rotating speed of a peristaltic pump is 30rpm.
(4) And (3) placing the powder obtained in the step (3) into a crucible, sintering in an air atmosphere, and naturally cooling after heat preservation is finished to obtain the manganese-based layered sodium-ion battery anode material. Wherein the sintering temperature is 900 ℃, and the sintering heat preservation time is 10 hours.
The chemical formula of the manganese-based layered sodium ion battery anode material provided in the embodiment is Na 0.67 Mn 0.8 Mg 0.2 O 2 。
The positive electrode materials of examples 1 to 5 were tested for the first-turn charge-discharge specific capacity and the capacity ratio in each potential interval.
TABLE 1
As can be seen from the above examples 1 to 5, the manganese-based layered sodium ion positive electrode material of the present invention has a specific discharge capacity of 134.7mAh/g or more, a voltage ratio of 95.7% between 3.0V and 4.35V, and a high discharge power. As can be seen from the comparison of examples 1 to 5, when the mass ratio of Na element in the manganese-based layered sodium ion positive electrode material is 17.2%, the mass ratio of Mn element is 30.9%, the mass ratio of Ni element is 22.0% and the mass ratio of oxygen element is 29.9%, the prepared manganese-based layered sodium ion positive electrode material has higher specific discharge capacity; when the mass ratio of Na element in the manganese-based layered sodium ion positive electrode material is 14.8%, the mass ratio of Mn element is 31.7%, the mass ratio of Ni element is 17.0%, and the mass ratio of Cu element is 6.1%, the positive electrode material prepared by the method has higher specific capacity with a higher ratio between 3.0 and 4.35V.
The positive electrode materials obtained in examples 1 to 10 and comparative example 1 were prepared into positive electrode sheets and secondary batteries for cycle performance test, and the test results were recorded in table 2.
The sodium ion secondary battery is charged to 4.35V at a constant current of 0.1C, then charged to 0.05C at a constant voltage of 4.35V, kept stand for 5min, and then discharged to 2.0V at a constant current of 0.1C, which is a charge-discharge cycle process, and the discharge capacity at this time is the discharge capacity of the first cycle. The sodium ion secondary battery was subjected to 100-cycle charge-discharge test according to the above method, and the discharge capacity per cycle was recorded. Cycle capacity retention (%) =discharge capacity of the 100 th cycle/discharge capacity of the first cycle×100%.
TABLE 2
As can be seen from the comparison of examples 1 to 10 and comparative example 1, the secondary battery prepared by the present invention has better electrochemical performance, and the capacity retention rate after 100 charge and discharge cycles still has a cyclic capacity retention rate of 86% or more, and has good electrochemical performance. As shown by comparison of examples 1 and 6-10, when the precursor in the step S3 is placed in a muffle furnace to react for 8 hours at 900 ℃, the prepared positive electrode material has a cyclic capacity retention rate of up to 89%.
Variations and modifications of the above embodiments will occur to those skilled in the art to which the invention pertains from the foregoing disclosure and teachings. Therefore, the present invention is not limited to the above-described embodiments, but is intended to be capable of modification, substitution or variation in light thereof, which will be apparent to those skilled in the art in light of the present teachings. In addition, although specific terms are used in the present specification, these terms are for convenience of description only and do not limit the present invention in any way.

Claims (12)

1. The manganese-based layered oxide positive electrode material is characterized in that the mass ratio of Na element is 10-20%, the mass ratio of Mn element is 30-45%, the mass ratio of doped metal element Me is 1-25%, the balance is oxygen, and the doped metal element Me is at least one of Ni, fe, mg, co, cu, ti; the 2 theta diffraction angle of the manganese-based layered oxide positive electrode material has the following characteristic peaks under the XRD spectrum of a copper target K alpha 1: 15.8-16.2 °, 31.9-32.3 °, 35.7-36.1 °, 39.2-39.6 °, 43.3-43.7 °, 48.7-49.1 °, 62.1-62.5 °, 64.3-64.7 °, 66.6-67 °, and 66.9-67.3 °.
2. The manganese-based layered oxide cathode material according to claim 1, wherein the manganese-based layered oxide cathode material has a single crystal morphology of 2-6 μm.
3. The method for preparing a manganese-based layered oxide cathode material according to claim 1 or 2, comprising the steps of:
s1, dissolving a sodium source, a manganese source and a doped metal source in a solvent to obtain a precursor mixed solution;
s2, transferring the precursor mixed solution into a hydrothermal kettle for precipitation reaction, filtering, washing and drying the precipitate to obtain a precursor;
and step S3, placing the precursor in a muffle furnace for sintering to obtain the manganese-based layered oxide cathode material.
4. The method for preparing a manganese-based layered oxide cathode material according to claim 3, wherein in the step S1, the mass ratio of the sodium source to the manganese source to the doped metal source is 1-30: 2-20: 1 to 20.
5. The method for preparing a manganese-based layered oxide cathode material according to claim 3, wherein the sodium source is one or a mixture of two or more of sodium nitrate, sodium carbonate, sodium bicarbonate and sodium hydroxide; the manganese source is one or a mixture of more than two of manganese nitrate, manganese acetate, manganese sulfate and manganese chloride; the doped metal source is one or more than two of carbonate, acetate, chloride and sulfate.
6. The method for preparing a manganese-based layered oxide cathode material according to claim 3, wherein the solvent in the step S1 is one or a mixture of two or more of water, isopropanol, ethanol and methanol.
7. The method for preparing a manganese-based layered oxide cathode material according to claim 3, wherein the precipitation reaction temperature in the step S2 is 120 ℃ to 160 ℃ and the reaction time is 6 to 10 hours.
8. The method for preparing a manganese-based layered oxide cathode material according to claim 3, wherein the sintering temperature in the step S3 is 700 ℃ to 1000 ℃ and the sintering time is 6 hours to 12 hours.
9. A positive electrode sheet comprising the manganese-based layered oxide positive electrode material according to claim 1 or 2.
10. A secondary battery comprising the positive electrode sheet according to claim 9.
11. The secondary battery according to claim 10, wherein the secondary battery has at least two charge and discharge plateau in a charge and discharge curve at a voltage interval of 2.0 to 4.35V and a current density of 0.1C.
12. The secondary battery according to claim 10, wherein the capacity ratio of the secondary battery at a voltage interval of 4.0 to 4.35V and a current density of 0.1C is 30 to 50%; the capacity ratio under the voltage interval of 3.0-4.0V and the current density of 0.1C is 40-60 percent; the capacity ratio is 1-20% under the voltage interval of 2.0-3.0V and the current density of 0.1C.
CN202311202747.0A 2023-09-18 2023-09-18 Manganese-based layered oxide positive electrode material, preparation method thereof, positive electrode sheet and secondary battery Pending CN117096336A (en)

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