LiVO3Electrode material and rapid preparation method thereof
阅读说明：本技术 LiVO3电极材料及其快速制备方法 (LiVO3Electrode material and rapid preparation method thereof ) 是由 曹知勤 左承阳 张雪峰 何逵 庞立娟 郑成松 滕海军 段川游 于 2021-08-24 设计创作，主要内容包括：本发明涉及一种LiVO-(3)正极材料及其快速制备方法,属于储能材料技术领域。本发明的LiVO-(3)电极材料的快速制备方法包括：a.将硝酸铵,偏钒酸铵,胺类有机物,硝酸锂,柠檬酸,葡萄糖与水混合,溶解得到溶液A；b.将所述溶液A加热至水分蒸发完后,剩余物质迅速反应膨胀,生成蓬松的物质B；c.将所述物质B煅烧,得到LiVO-(3)粉末。本发明制备方法反应快,耗时段,生产效率高。本发明的方法制备得到的材料纯度高以该材料作为锂离子电池正极材料组装为电池,具有良好的电化学性能。(The invention relates to LiVO 3 A positive electrode material and a rapid preparation method thereof belong to the technical field of energy storage materials. LiVO of the invention 3 The rapid preparation method of the electrode material comprises the following steps: a. mixing ammonium nitrate, ammonium metavanadate, amine organic matters, lithium nitrate, citric acid and glucose with water, and dissolving to obtain a solution A; b. heating the solution A until the water is evaporated, and then quickly reacting and expanding the residual substances to generate fluffy substances B; c. calcining the substance B to obtain LiVO 3 And (3) powder. The preparation method has the advantages of quick reaction, time-consuming period and high production efficiency. The material prepared by the method has high purity, is assembled into a battery by taking the material as a lithium ion battery anode material, and has good electrochemical performance.)
1.LiVO3A method for the rapid preparation of an electrode material, the method comprising:
a. mixing ammonium nitrate, ammonium metavanadate, amine organic matters, lithium nitrate, citric acid and glucose with water, and dissolving to obtain a solution A;
b. heating the solution A until the water is evaporated, and then quickly reacting and expanding the residual substances to generate fluffy substances B;
c. calcining the substance B to obtain LiVO3And (3) powder.
2. LiVO according to claim 13The rapid preparation method of the electrode material is characterized in that the amine organic matters are glycine, lysine and urea.
3. LiVO according to claim 1 or 23The rapid preparation method of the electrode material is characterized in that the molar ratio of ammonium nitrate, ammonium metavanadate, amine organic matters, lithium nitrate, citric acid and glucose is as follows: 5-30: 1: 0.5-3: 1: 2-12: 0.1-1.
4. LiVO according to claim 1 or 23The rapid preparation method of the electrode material is characterized in that the calcining temperature in the step c is 300-500 ℃.
5. LiVO according to claim 43The rapid preparation method of the electrode material is characterized in that the calcining temperature in the step c is 350-450 ℃.
6. LiVO according to claim 1 or 23The rapid preparation method of the electrode material is characterized in that the calcining time in the step c is 0.5-2 hours.
7. LiVO according to claim 63The rapid preparation method of the electrode material is characterized in that the calcining time in the step c is 1-1.5 hours.
8. LiVO according to claim 1 or 23The rapid preparation method of the electrode material is characterized in that the calcining atmosphere in the step c is air.
9.LiVO3An electrode material, characterized in that the LiVO3The electrode material is prepared by the method of any one of claims 1 to 8.
10. LiVO according to claim 93An electrode material, characterized in that the LiVO3Purity of electrode material>99.9％。
Technical Field
The invention relates to LiVO3A positive electrode material and a rapid preparation method thereof belong to the technical field of energy storage materials.
Background
With the continuous development of society, people greatly increase the energy demand, how to realize the transmission of the energy is more convenient, the loss is reduced, and the portability of the energy is a huge problem. Traditional fossil energy resources are rapidly consumed, and development and utilization of new energy sources have become a focus of world attention. Some new energy sources currently in use have instability, for example, solar energy which is widely used at present still can be influenced by factors such as illumination intensity, illumination duration and the like, and development and utilization of the new energy sources are urgently needed to be supported by means of advanced energy storage technology.
Lithium ion batteries are currently an advanced energy storage technology, and have become an indispensable role in the field of new energy application since the lithium ion batteries are commercialized for the first time to date. Although the current lithium ion battery has a mature application market, the reliability and safety of the current lithium ion battery still cannot meet the requirement of people for rapid development. The positive electrode material of the lithium ion battery directly influences the specific capacity of the battery, is the key for improving the performance of the battery and is an important factor for restricting the development of the lithium ion battery.
Many studies and applications of the positive electrode material for lithium ion batteries have been made, but the studies and research on the positive electrode material for lithium ion batteries are still ongoing.
Vanadium-based oxide positive electrode materials have received wide attention from the world due to the abundant resources and valence states of vanadium. The synthesis of vanadium oxides and derivatives thereofA great deal of work is done in the aspect of characterization, LiVO3The vanadium-based composite cathode material has high theoretical specific capacity, long cycle life and high structural stability relative to other vanadium-based compounds, and is considered as one of the future commercial cathode material candidates.
Conventional LiVO3The synthesis method includes a high-temperature solid-phase melting method, a hydrothermal synthesis method, a sol-gel method and the like. The high-temperature solid-phase melting method has the problems of long time consumption, more impure phases of the obtained product, uneven particles and the like, greatly influences the electrochemical performance of the material, and simultaneously restricts the popularization and application of the material. The high-temperature solid phase method has the advantages of simple and convenient operation, simple process, easy realization of industrial production and the like. But has long high-temperature reaction time and large energy consumption; the volatilization degrees of lithium and vanadium are different at high temperature, and vanadium corrodes vessels and other losses, so that the proportion of lithium and vanadium is difficult to control at an expected metering value; the high-temperature reaction product can be used only after certain post-treatment; the product has the defects of large grain diameter, higher crystallinity, lower capacity caused by uneven grain size, shorter service life and the like.
The sol-gel method is the most studied method in the lithium vanadate low-temperature liquid phase synthesis method, and has the advantages of low reaction temperature, uniform product granularity, small size and the defects of complicated steps and long time consumption. The hydrothermal synthesis method is a preparation method for obtaining highly crystallized powder by placing a precursor at a certain temperature and pressure for hydrothermal reaction. However, the hydrothermal synthesis method has high requirements on equipment, limited preparation amount and high industrial production difficulty.
LiVO (lithium ion battery positive electrode material) of simple snow plum3Preparation and electrochemical Properties [ D ] thereof]Zhejiang university discloses a solid phase method for preparing LiVO3The method for preparing the material mainly comprises two steps, namely mixing a medicine to obtain a precursor, and calcining at a certain temperature for a certain time and then cooling along with a furnace to obtain the material. Ball milling the mixed material with Li2CO3And NH4VO3Taking ethanol as a solvent as a raw material, ball-milling by adopting a planetary ball mill to obtain a uniformly mixed precursor (the rotating speed is 300r/min, the time is 10 hours, and then using ethanol to ball-mill the obtained slurryWashing with alcohol, transferring into a beaker, drying in an oven at 60 deg.C, and calcining at 300 deg.C to 500 deg.C for 12 hr to obtain the final product. Another method is to use oxalic acid and Li2CO3And NH4VO3Grinding raw materials in a mortar for 0.5h to 1h until the raw materials are mixed to form dark reddish brown slurry, then putting the slurry into a drying oven at 90 ℃ for drying, and finally calcining at a certain temperature for 10h to obtain the material. The preparation time is very long, and the production efficiency is low.
Homing, Huzhong, Luxiangzhong, and the like, condition optimization research on preparation of lithium vanadate serving as lithium ion battery anode material by sol-gel method [ J]2012(S3):663-4VO3) And lithium acetate (CH)3COOLi.2H2O) as raw material, citric acid (C)6H8O7.H2O) is taken as a chelating agent, and a sol-gel method is adopted to prepare the LiV3O8The anode material and the synthesis conditions are optimized. The crystal structure, the surface morphology and the electrochemical performance of the synthesized material are characterized by applying the technologies of X-ray diffraction (XRD), a Scanning Electron Microscope (SEM), charge and discharge tests, alternating current impedance spectroscopy (EIS) and the like. The result shows that the optimal optimized conditions of the lithium vanadate anode material are that the pH value of a precursor solution is 3, the sintering temperature is 450 ℃, and the sintering time is 15 h. The charge-discharge test shows that the LiV is synthesized under the optimal condition3O8The first discharge capacity can reach 269.4mAh-1220.9mAh g after 50 times of circulation-1And the electrochemical performance is excellent. However, the preparation time is very long, the energy consumption is high, and the production efficiency is very low.
CN104241626A discloses a sol-gel preparation method of a lithium vanadate anode material of a lithium ion battery, which comprises: sequentially adding precursors of a vanadium-containing compound and a lithium-containing compound into water, fully stirring, adding a water-soluble carbon material serving as a chelate and a carbon source, stirring the water solution until a dry gel is formed, drying the water completely by vacuum drying, placing the colloid into a porcelain boat, pretreating in a reducing atmosphere or an inert atmosphere, and sintering and reacting in the inert atmosphere or the reducing atmosphere to obtain the material. The method has simple process and easy operation, and the structure of the lithium vanadate and the valence state of the vanadium cannot be changed due to the existence of the carbon material and the reducing atmosphere. The carbon-coated lithium vanadate material synthesized by the method has excellent performance as a lithium ion battery cathode material and low lithium intercalation potential, and is expected to become a next generation lithium ion battery cathode material. The synthesis method is suitable for producing the lithium vanadate serving as the negative electrode material of the high-performance lithium ion battery. However, the product is different from the method, needs a reducing atmosphere reaction, and has high cost, the pretreatment time is 2-12 h, the calcination time is 2-12 h, and the total time is more than 4h, the reaction time is long, the energy consumption is high, and the production efficiency is low.
Disclosure of Invention
The first purpose of the invention is to provide LiVO3A rapid preparation method of electrode material.
In order to achieve the first object of the invention, the LiVO3The rapid preparation method of the electrode material comprises the following steps:
a. mixing ammonium nitrate, ammonium metavanadate, amine organic matters, lithium nitrate, citric acid and glucose with water, and dissolving to obtain a solution A;
b. heating the solution A until the water is evaporated, and then quickly reacting and expanding the residual substances to generate fluffy substances B;
c. calcining the substance B to obtain LiVO3And (3) powder.
The amount of water added in step a is such that the raw materials can be dissolved.
In a specific embodiment, the amine organic compound is glycine, lysine, or urea.
In a specific embodiment, the molar ratio of ammonium nitrate, ammonium metavanadate, amine organic matter, lithium nitrate, citric acid and glucose is as follows: 5-30: 1: 0.5-3: 1: 2-12: 0.1-1.
In a specific embodiment, the temperature of the calcination in the step c is 300 to 500 ℃, preferably 300 to 450 ℃.
In a specific embodiment, the calcination time in step c is 0.5 to 2 hours, preferably 1 to 1.5 hours.
In one embodiment, the atmosphere for the calcination in step c is air.
The second purpose of the invention is to provide a new LiVO3An electrode material.
To achieve the second object of the present invention, the LiVO3The electrode material is prepared by the method.
In one embodiment, the LiVO3Purity of electrode material>99.9％。
Has the advantages that:
1. the preparation method has the advantages of quick reaction, time-consuming period and high production efficiency.
2. The material prepared by the method has high purity, is assembled into a battery by taking the material as a lithium ion battery anode material, and has good electrochemical performance.
Drawings
FIG. 1 is a diagram showing a process for preparing a lithium vanadate precursor according to example 1;
FIG. 1 (a) initial solution; (b) in the heating process; (c) gel formation; (d) carrying out a reaction process; (e) the reaction was complete.
FIG. 2 is an XRD pattern of a lithium vanadate precursor of example 1.
FIG. 3 is an XRD pattern of lithium vanadate as the product of example 1.
FIG. 4 shows the product of example 1, lithium vanadate.
FIG. 5 is a graph showing the cycle charge and discharge performance of lithium vanadate as an electrode material in example 1.
FIG. 6 is a graph showing the rate capability test of example 1.
Detailed Description
In order to achieve the first object of the invention, the LiVO3The rapid preparation method of the electrode material comprises the following steps:
a. mixing ammonium nitrate, ammonium metavanadate, amine organic matters, lithium nitrate, citric acid and glucose with water, and dissolving to obtain a solution A;
b. heating the solution A until the water is evaporated, and then quickly reacting and expanding the residual substances to generate fluffy substances B;
c. calcining the substance B to obtain LiVO3And (3) powder.
The fluffy substance B is the lithium vanadate precursor.
In a specific embodiment, the amine organic compound is glycine, lysine, or urea.
In a specific embodiment, the molar ratio of ammonium nitrate, ammonium metavanadate, amine organic matter, lithium nitrate, citric acid and glucose is as follows: 5-30: 1: 0.5-3: 1: 2-12: 0.1-1.
In a specific embodiment, the temperature of the calcination in the step c is 300 to 500 ℃, preferably 300 to 450 ℃.
In a specific embodiment, the calcination time in step c is 0.5 to 2 hours, preferably 1.0 to 1.5 hours.
In one embodiment, the atmosphere for the calcination in step c is air.
To achieve the second object of the present invention, the LiVO3The electrode material is prepared by the method.
In one embodiment, the LiVO3Purity of electrode material>99.9％。
The following examples are provided to further illustrate the embodiments of the present invention and are not intended to limit the scope of the present invention.
Example 1
Weighing 0.4mol of ammonium nitrate, 0.05mol of ammonium metavanadate, 0.16mol of citric acid, 0.05mol of lithium nitrate, 0.04mol of glycine and 0.05mol of glucose. Dissolving the weighed substances by using water as a solution, and heating the substances in a universal furnace in the dissolving process, wherein the dissolving process is as follows: the starting solution is pale yellow, since vanadium is present in the +5 valency; the drug was completely dissolved, the solution changed in color from light yellow to yellow, then to greenish black and finally to blue, at which time vanadium changed from +5 to +3 to +4, and the solution changed in color as shown in (a) - (d) of fig. 1. Boiling the solution until the deionized water is completely evaporated, reacting the residual substances, rapidly expanding the reaction to finally generate brown fluffy substances, and finishing the reaction within a few minutes to obtain the precursorThe product, shown in fig. 1 (e), is vanadium oxide of amorphous titanium, and its XRD diffraction pattern is shown in fig. 2. And (3) placing the precursor in a muffle furnace, adjusting the calcination temperature to 400 ℃, calcining for 1 hour in an air atmosphere, and performing XRD phase analysis on a product obtained by calcining, wherein the result is shown in figure 3, and the result is shown in figure 4. The diffraction peak and LiVO of the material can be obviously seen from the figure3The characteristic peaks of the compounds are completely consistent without redundant miscellaneous peaks, and the product purity is obtained>99.9. The obtained LiVO3The material is used as the anode material of the lithium ion battery to be manufactured into the battery, and the manufacturing method of the battery comprises the following steps:
firstly, weighing 1g of PVDF by using weighing paper, and transferring the PVDF into a brown volume vial which is cleaned and dried; weighing the small bottle with the medicine on a balance, and peeling; 19g of NMP (N-methylpyrrolidone) was dropped with a rubber dropper; after weighing was completed, a stirring rotor was added and stirred overnight with a magnetic stirrer until the PVDF was completely dissolved, to obtain a 5% PVDF solution.
The prepared positive electrode material, the binder and the acetylene black are weighed according to the mass ratio of 7:2:1, and the weighed positive electrode material and the acetylene black are poured into an agate mortar to be ground for about 20min and are fully mixed. And putting the ground active substance, the acetylene black mixture and the binder into a vacuum drying oven, and drying at 55 ℃ for 25 min. After drying, the binder and ground material are removed and the binder is poured into a mortar and ground while hot until no granules are present and the solution flows slowly. The resulting slurry was coated on an aluminum foil with a 60mm coater. And putting the coated aluminum foil into a vacuum drying oven, and performing vacuum drying at 100 ℃ for 10 hours. And putting the vacuum-dried aluminum foil on a slicing machine for slicing, weighing the coated aluminum foil, and numbering. And (4) drying the cut aluminum sheet and the diaphragm in vacuum for 2 hours, and then putting the aluminum sheet and the diaphragm into a glove box.
The button cell is assembled in a vacuum glove box in argon atmosphere, and the glove box must ensure H2O and O2The concentrations were all below 0.1 ppm. The positive electrode is a previously cut circular pole piece, the negative electrode is a metal Li piece in the Tianjin lithium industry, the diaphragm material adopts a polypropylene porous membrane, and the electrolyte is 1MLiPF6Volume of additionEthylene Carbonate (EC) and dimethyl carbonate (DMC) in a 1:1 ratio. Put into vacuum glove box with electrode slice, diaphragm, earlier with dustless cloth clearance operation mesa, take out anodal shell, negative pole shell, gasket, lithium piece again, get appropriate amount of electrolyte with disposable rubber head burette, the battery is put into in proper order from bottom to top: positive electrode can-positive electrode sheet-electrolyte-diaphragm-lithium sheet-gasket-negative electrode can. And finally, finishing the final assembly work by using a button cell packaging machine.
And (3) performing constant-current charge and discharge tests on the button cell by adopting a BTS-5V/1mA battery test system, and performing charge and discharge cycle performance tests on the lithium vanadate anode material lithium ion battery at a rate of 0.1A within a charge and discharge voltage interval range of 1-3.5V.
The rate test was carried out using an electrochemical workstation CHI160, and the charge-discharge specific capacities at different current densities were tested at 50mA/g, 100mA/g, 200mA/g, 400mA/g, 800mA/g, 50mA/g, respectively, under the conditions of 1-3.5V.
The results of the cycle performance test are shown in FIG. 5 and Table 1, and the discharge capacity after 50 cycles is 193.6 mAh/g. The results of the rate test are detailed in fig. 6 and table 2.
TABLE 1 cycle performance test
Cycle number
Specific charging capacity/mAh/g
Specific discharge capacity/mAh/g
1
249.7
244.3
5
248.2
246.8
15
237.9
236.4
20
237.6
238.1
25
228.9
229.3
30
227.7
227
35
218.1
220.5
40
210.7
215.8
45
204.4
206
50
196.4
193.6
TABLE 2 Rate testing
Example 2
Weighing 0.4mol of ammonium nitrate, 0.05mol of ammonium metavanadate, 0.16mol of citric acid, 0.05mol of lithium nitrate, 0.05mol of glycine and 0.05mol of glucose. Dissolving the weighed substances by using water as a solution, heating the solution in a universal furnace in the dissolving process, wherein the reaction process is similar to that of the example 1, finally generating brown fluffy substances, and completing the reaction within a few minutes to obtain a precursor product, wherein the product is vanadium oxide of amorphous titanium. Placing the precursor in a muffle furnace, adjusting the calcining temperature to 500 ℃, and calcining for 0.5 hour in the air atmosphere to obtain the product with the purity>99.9 LiVO3And (3) powder. The obtained LiVO3The material is used as the anode material of the lithium ion battery to be made into the battery. The discharge capacity after 50 times of circulation is 192.6 mAh/g.
Example 3
Weighing 0.4mol of ammonium nitrate, 0.05mol of ammonium metavanadate, 0.16mol of citric acid, 0.05mol of lithium nitrate, 0.05mol of glycine and 0.05mol of glucose. Dissolving the weighed substances by using water as a solution, heating the solution in a universal furnace in the dissolving process, wherein the reaction process is similar to that of the example 1, finally generating brown fluffy substances, and completing the reaction within a few minutes to obtain a precursor product, wherein the product is vanadium oxide of amorphous titanium. Placing the precursor in a muffle furnace, adjusting the calcining temperature to 350 ℃, and calcining for 2 hours in air atmosphere to obtain the product with purity>99.9 LiVO3And (3) powder. The obtained LiVO3The material is used as the anode material of the lithium ion battery to be made into the battery. The discharge capacity after 50 times of circulation is 192.1 mAh/g.