Layered Co3O4Lithium ion battery cathode material and preparation method thereof
阅读说明：本技术 一种层状Co3O4锂离子电池负极材料及其制备方法 (Layered Co3O4Lithium ion battery cathode material and preparation method thereof ) 是由 李烁烁 程威 李华峰 卢必娟 顾鹏 王栋 于 2021-09-30 设计创作，主要内容包括：本发明公开了一种层状Co-(3)O-(4)锂离子电池负极材料及其制备方法,涉及电池的领域。包括以下步骤：S1、称取Co(NO-(3))-(2)·6H-(2)O和CoCl-(3)·6H-(2)O加入到含有氨水和乙二醇的形貌导向剂中,制得前驱体溶液；S2、对所述前驱体溶液进行搅拌,随后经溶剂热反应,制得固态悬浮液；S3、将所述固态悬浮液经过滤后保留固相产物,将固相产物清洗并干燥后,制得前驱体β-Co(OH)-(2)；S4、将所述前驱体β-Co(OH)-(2)置于空气氛围中加热煅烧后,即得层状Co-(3)O-(4)。本申请中获得具有棒状轮廓的层状Co-(3)O-(4),其自身的层状结构有助于加快锂离子的传输速率,提供稳定的放电平台,增强电池的倍率,提高材料的比容量。(The invention discloses a layered Co 3 O 4 A lithium ion battery cathode material and a preparation method thereof relate to the field of batteries. The method comprises the following steps: s1, weighing Co (NO) 3 ) 2 ·6H 2 O and CoCl 3 ·6H 2 Adding O into a morphology directing agent containing ammonia water and glycol to prepare a precursor solution; s2, stirring the precursor solution, and then carrying out solvothermal reaction to obtain a solid suspension; s3, filtering the solid suspension, reserving a solid phase product, cleaning and drying the solid phase product to obtain a precursor beta-Co (OH) 2 (ii) a S4, mixing the precursor beta-Co (OH) 2 Heating and calcining the mixture in the air atmosphere to obtain layered Co 3 O 4 . Obtained in this application with a rod-shaped profileLayered Co 3 O 4 The layered structure of the lithium ion battery is beneficial to accelerating the transmission rate of lithium ions, providing a stable discharge platform, enhancing the multiplying power of the battery and improving the specific capacity of the material.)
1. Layered Co3O4The preparation method of the lithium ion battery cathode material is characterized in thatThe method comprises the following steps:
s1, weighing Co (NO)3)2·6H2O and CoCl3·6H2Adding O into the morphology directing agent to prepare a precursor solution;
s2, stirring the precursor solution, and then carrying out solvothermal reaction to obtain a solid suspension;
s3, filtering the solid suspension, reserving a solid phase product, cleaning and drying the solid phase product to obtain a precursor beta-Co (OH)2；
S4, mixing the precursor beta-Co (OH)2Heating and calcining the mixture in the air atmosphere to obtain layered Co3O4；
Wherein the morphology directing agent is a mixed solution of ammonia water and ethylene glycol.
2. A layered Co composition according to claim 13O4The preparation method of the lithium ion battery negative electrode material is characterized in that in the step S4, the calcination is to obtain a precursor beta-Co (OH)2Heating to 450-550 ℃ in air atmosphere, wherein the heating rate is 1 ℃/min, and then keeping the constant temperature for 1-3 h.
3. A layered Co composition according to claim 13O4The preparation method of the lithium ion battery cathode material is characterized in that in the S1, the mass fraction of ammonia water in the morphology directing agent is 5% -10%.
4. A layered Co composition according to claim 13O4The preparation method of the lithium ion battery negative electrode material is characterized in that in the step S1, the concentration of the precursor solution is 0.2-0.6 mol/L.
5. A layered Co as claimed in any one of claims 1 to 43O4A method for preparing a negative electrode material for a lithium ion battery, wherein in S1, the Co (NO) is3)2·6H2O and CoCl3·6H2The molar ratio of O is 1: 1.
6. a layered Co composition according to claim 13O4The preparation method of the lithium ion battery cathode material is characterized in that in the step S1, the solvothermal reaction is to place the stirred precursor solution in a reaction device at 180-250 ℃ for 12-24 h.
7. A layered Co composition according to claim 13O4The preparation method of the lithium ion battery cathode material is characterized in that in the step S3, the cleaning is to sequentially clean the solid-phase product by adopting ethanol and deionized water.
8. A layered Co composition according to claim 13O4The preparation method of the lithium ion battery negative electrode material is characterized in that in the step S3, the drying is to dry the solid-phase product for 24 hours at the temperature of 60 ℃.
9. A layered Co composition according to claim 13O4The preparation method of the lithium ion battery negative electrode material is characterized in that in the step S2, the stirring time is 1-2 h.
10. Layered Co3O4The lithium ion battery cathode material is characterized by comprising layered Co for preparing the lithium ion battery cathode material3O4Said layered Co3O4Using a layered Co as claimed in any one of claims 1 to 93O4The layered Co is prepared by a preparation method of a lithium ion battery cathode material3O4Is a laminated stack structure of the laminated Co3O4The stack forms a rod-like profile.
Technical Field
The invention relates to the field of batteries, in particular to layered Co3O4A lithium ion battery cathode material and a preparation method thereof.
Background
With the rapid increase of the number of the population in the world, the problem of energy shortage is increasingly serious, the main energy storage devices at present comprise chemical power supply energy storage and mechanical energy storage, the mechanical energy storage has uncontrollable randomness and variability, compared with the higher requirement of the mechanical energy storage on the environment, the chemical energy storage has higher energy density and power density and easy portability, and the chemical energy storage is mainly provided with a lithium ion battery, a lead-acid battery, a liquid flow battery and the like and is widely applied to the industries of consumer electronics and electric automobiles.
Compared with the traditional secondary battery, the lithium ion battery has the advantages of high working voltage, large specific energy, stable discharge voltage, long cycle life, no environmental pollution and the like. The negative electrode material is one of the key materials of the lithium battery, mainly comprises carbon materials such as graphite, porous carbon and the like, but the carbon materials have low specific capacity, poor rate capability and low structural rigidity, are easy to agglomerate and pulverize, are not beneficial to prolonging the service life of the lithium battery, so that the graphite negative electrode material used by the current commercial lithium ion battery has low specific capacity, the specific capacity range is 200-400mAh/g, and can not meet the energy requirement of rapid development.
Disclosure of Invention
The invention provides a layered Co3O4The material utilizes the layered structure of the material to accelerate the transmission rate of lithium ions and improve the specific capacity so as to solve the problem of lithium batteriesThe specific capacity of the negative electrode material is low.
To solve the above technical problems, an object of an embodiment of the present invention is to provide a layered Co3O4The preparation method of the lithium ion battery negative electrode material comprises the following steps:
s1, weighing Co (NO)3)2·6H2O and CoCl3·6H2Adding O into the morphology directing agent to prepare a precursor solution;
s2, stirring the precursor solution, and then carrying out solvothermal reaction to obtain a solid suspension;
s3, filtering the solid suspension, reserving a solid phase product, cleaning and drying the solid phase product to obtain a precursor beta-Co (OH)2；
S4, mixing the precursor beta-Co (OH)2Heating and calcining the mixture in the air atmosphere to obtain layered Co3O4；
Wherein the morphology directing agent is a mixed solution of ammonia water and ethylene glycol.
By the above scheme, CO3 2+With OH in ammonia-The precursor beta-Co (OH) with hydrotalcite layered double-hydroxyl structure is generated by reaction2Organic small molecules of ammonia water and ethylene glycol in the morphology directing agent are hydrogen bonded with a precursor beta-Co (OH)2OH of dihydroxyl structure-Connected and inserted between the layers to avoid stacking between the layers and further avoid ion channel disappearance, and finally, the layered Co with overall rod-shaped outline is obtained by calcination and dehydration3O4The layered Co3O4By lamellar Co between different layers3O4Stacked to form a rod-shaped profile, the original layered structure is maintained in the calcining process, the morphology of the calcining process is not changed, and the Co of the layered stack3O4The material is more beneficial to improving the transmission speed of Li ions, is convenient for the insertion or extraction of the Li ions, improves a stable discharge platform, enhances the multiplying power of the battery, improves the specific capacity of the material, and can reach 900 mAh/g.
Preferably, inIn the S4, the calcination is to convert the precursor beta-Co (OH)2Heating to 450-550 ℃ in air atmosphere, wherein the heating rate is 1 ℃/min, and then keeping the constant temperature for 1-3 h.
By adopting the scheme, the precursor is beta-Co (OH)2The interlaminar ammonia water and the glycol form carbon after high-temperature calcination, thereby accelerating Co3O4By controlling the Co temperature during calcination by limiting the ramp rate and final heating temperature3O4The lattice spacing is widened, and the wider lattice spacing is beneficial to the transmission of lithium ions, so that the specific capacity of the material is improved.
Preferably, in the S1, the mass fraction of ammonia water in the morphology directing agent is 5% to 10%.
Preferably, in the step S1, the concentration of the precursor solution is 0.2mol/L-0.6 mol/L.
Preferably, in the S1, the Co (NO)3)2·6H2O and CoCl3·6H2The molar ratio of O is 1: 1.
preferably, in the S1, the solvothermal reaction is to place the stirred precursor solution in a reaction apparatus at 180-250 ℃ for 12-24 h.
Preferably, in S3, the washing is to wash the solid-phase product with ethanol and deionized water sequentially.
Preferably, in the S3, the drying is to dry the solid phase product for 24 hours at a temperature of 60 ℃.
Preferably, in the step S2, the stirring time is 1h to 2 h.
To solve the above technical problems, it is a second object of the embodiments of the present invention to provide a layered Co3O4The lithium ion battery cathode material comprises layered Co used for preparing the lithium ion battery cathode material3O4Said layered Co3O4Using a layered Co as described above3O4The layered Co is prepared by a preparation method of a lithium ion battery cathode material3O4Is a laminated stack structure of the laminated Co3O4The stack forms a rod-like profile.
Compared with the prior art, the embodiment of the invention has the following beneficial effects:
1. the precursor beta-Co (OH) with hydrotalcite layered double-hydroxyl structure can be generated after the solvothermal reaction2Organic micromolecules of ammonia water and ethylene glycol in the morphology guiding agent are inserted between layers, stacking between the same layers is avoided, and finally, the lamellar Co with a rod-shaped outline is obtained by calcining and dehydrating3O4The layered stacked Co3O4The material is more beneficial to improving the transmission speed of Li ions, improving a stable discharge platform, enhancing the multiplying power of the battery and improving the specific capacity of the material, and the specific discharge capacity can reach 900 mAh/g.
2. Precursor beta-Co (OH)2The interlaminar ammonia water and the glycol form carbon after high-temperature calcination, thereby accelerating Co3O4By controlling the Co temperature during calcination by limiting the ramp rate and final heating temperature3O4The lattice spacing is widened, and the wider lattice spacing is beneficial to the transmission of lithium ions, so that the specific capacity of the material is improved.
Drawings
FIG. 1: a layered Co layer in the first embodiment of the invention3O4An XRD diffraction peak spectrum of the lithium ion battery negative electrode material;
FIG. 2: a layered Co layer in the first embodiment of the invention3O4SEM image of lithium ion battery cathode material with resolution of 500 nm;
FIG. 3: a layered Co layer in the first embodiment of the invention3O4TEM image with resolution of 0.5 μm of lithium ion battery negative electrode material;
FIG. 4: a layered Co layer in the first embodiment of the invention3O4SEM image of lithium ion battery cathode material with resolution of 5 nm;
FIG. 5: a layered Co layer in the first embodiment of the invention3O4Charging and discharging of lithium ion battery cathode materialGraph of electrical characteristics (Note: 1)st、2nd、4th、5thEach representing a different number of cycles of the same sample).
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Layered Co3O4The lithium ion battery cathode material comprises layered Co which can be used for preparing the lithium ion battery cathode material3O4Of layered Co3O4Is a laminated stack structure of laminated Co3O4The bar-shaped profile is formed after stacking, and the bar-shaped profile is prepared by the following steps:
s1, mixing Co (NO)3)2·6H2O and CoCl3·6H2O is mixed according to a molar ratio of 1: 1, and then adding the mixture into 60mL of morphology directing agent to prepare a precursor solution, wherein the concentration of the precursor solution is 0.33mol/L, and the morphology directing agent is a mixed solution containing glycol and 8.3 wt% of ammonia water;
s2, stirring the precursor solution for 1h, then transferring the fully reacted precursor solution to a reaction kettle for solvothermal reaction, controlling the reaction temperature to be 220 ℃ and the heating time to be 18h, standing the reaction kettle after the heating is finished, and cooling to room temperature to obtain a solid suspension;
s3, filtering the solid suspension, reserving the solid phase product, washing the solid phase product for 3 times by using absolute ethyl alcohol and deionized water respectively, and then drying the solid phase product in a drying oven at the temperature of 60 ℃ for 24 hours to obtain a precursor beta-Co (OH)2；
S4, mixing the precursor beta-Co (OH)2Arranged in a tubeHeating and calcining in a furnace in air atmosphere, controlling the heating rate at 1 ℃/min, heating to 500 ℃, and keeping the constant temperature for 1h to obtain the layered Co3O4。
Example two
Layered Co3O4The lithium ion battery cathode material comprises layered Co which can be used for preparing the lithium ion battery cathode material3O4Of layered Co3O4Is a laminated stack structure of laminated Co3O4The bar-shaped profile is formed after stacking, and the bar-shaped profile is prepared by the following steps:
s1, mixing Co (NO)3)2·6H2O and CoCl3·6H2O is mixed according to a molar ratio of 1: 1, and then adding the mixture into 60mL of morphology directing agent to prepare a precursor solution, wherein the concentration of the precursor solution is 0.6mol/L, and the morphology directing agent is a mixed solution containing glycol and 10 wt% of ammonia water;
s2, stirring the precursor solution for 2 hours, transferring the fully reacted precursor solution to a reaction kettle for solvothermal reaction, controlling the reaction temperature to be 180 ℃ and the heating time to be 24 hours, standing the reaction kettle after the heating is finished, and cooling to room temperature to obtain a solid suspension;
s3, filtering the solid suspension, reserving the solid phase product, washing the solid phase product for 3 times by using absolute ethyl alcohol and deionized water respectively, and then drying the solid phase product in a drying oven at the temperature of 60 ℃ for 24 hours to obtain a precursor beta-Co (OH)2；
S4, mixing the precursor beta-Co (OH)2Placing in a tube furnace, heating and calcining in air atmosphere, controlling the heating rate at 1 deg.C/min, heating to 450 deg.C, and maintaining the constant temperature for 3 hr to obtain layered Co3O4。
EXAMPLE III
Layered Co3O4The lithium ion battery cathode material comprises layered Co which can be used for preparing the lithium ion battery cathode material3O4Of layered Co3O4Is in the form of layersStacked structure, layered Co3O4The bar-shaped profile is formed after stacking, and the bar-shaped profile is prepared by the following steps:
s1, mixing Co (NO)3)2·6H2O and CoCl3·6H2O is mixed according to a molar ratio of 1: 1, and then adding the mixture into 60mL of morphology directing agent to prepare a precursor solution, wherein the concentration of the precursor solution is 0.2mol/L, and the morphology directing agent is a mixed solution containing ethylene glycol and 5 wt% of ammonia water;
s2, stirring the precursor solution for 2 hours, transferring the fully reacted precursor solution to a reaction kettle for solvothermal reaction, controlling the reaction temperature to be 250 ℃ and the heating time to be 12 hours, standing the reaction kettle after the heating is finished, and cooling to room temperature to obtain a solid suspension;
s3, filtering the solid suspension, reserving the solid phase product, washing the solid phase product for 3 times by using absolute ethyl alcohol and deionized water respectively, and then drying the solid phase product in a drying oven at the temperature of 60 ℃ for 24 hours to obtain a precursor beta-Co (OH)2；
S4, mixing the precursor beta-Co (OH)2Placing in a tube furnace, heating and calcining in air atmosphere, controlling the heating rate at 1 deg.C/min, heating to 550 deg.C, and maintaining the constant temperature for 1 hr to obtain layered Co3O4。
Results of performance testing
As can be seen from the results of FIG. 1, the layered Co obtained in the first example3O4Diffraction peak pattern formed by material and Co3O4The diffraction peak patterns formed by the standard cards correspond to each other, and the Co material obtained in the first example is proved to be3O4。
As is clear from the results of FIGS. 2, 3 and 5, example 1 is based on CO3 2+With OH in ammonia-The precursor beta-Co (OH) with hydrotalcite layered double-hydroxyl structure is generated by reaction2Organic small molecules of ammonia water and ethylene glycol in the morphology directing agent are hydrogen bonded with a precursor beta-Co (OH)2OH of dihydroxyl structure-Is connected and inserted intoInterlamination is avoided, and finally, the layered Co is obtained by calcining and dehydrating3O4The original layered structure is kept in the calcining process, the whole body is in a rod-like structure, and the morphology change does not occur in the calcining process. As shown in FIG. 5, both 1.25V and 2.0V had significant charge-discharge plateaus during charging and discharging, and there was a large difference between the first charge and discharge specific capacities, indicating that the layered Co was layered3O4Formation of a surface SEI film and loss of electrochemically active sites when used as an anode material. Co illustrating the layered stack3O4The material is more favorable for improving the transmission speed of Li ions, improving a stable discharge platform, enhancing the multiplying power of the battery and improving the specific capacity of the material, and the specific capacity of the material is 1Ag-1At a current density of (2), making the layered Co3O4The specific discharge capacity of the material reaches 900 mAh/g.
As is clear from the results of FIGS. 4 and 5, the precursor beta-Co (OH)2The interlaminar ammonia water and the glycol form carbon after high-temperature calcination, thereby accelerating Co3O4By controlling the Co temperature during calcination via the ramp rate and final heating temperature3O4To widen the lattice spacing, layered Co3O4The crystal spacing can influence the Li + insertion and extraction in the lithium ion battery, and the layered Co is seen in the result of high-power TEM image3O4The lattice spacing of the material is 0.46nm, and the wider lattice spacing is beneficial to the transmission of lithium ions and improves the specific capacity of the material.
The above-mentioned embodiments are provided to further explain the objects, technical solutions and advantages of the present invention in detail, and it should be understood that the above-mentioned embodiments are only examples of the present invention and are not intended to limit the scope of the present invention. It should be understood that any modifications, equivalents, improvements and the like, which come within the spirit and principle of the invention, may occur to those skilled in the art and are intended to be included within the scope of the invention.
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