CN105280898A - Vanadium-doped lithium nickel cobalt manganese oxide nanometer material and preparation method and application thereof - Google Patents

Abstract

The invention relates to a preparation method of vanadium-doped lithium-nickel-cobalt-manganese oxide nanomaterials, which can be used as positive electrode active materials for lithium-ion batteries and have a layered structure of α- _NaFeO2 , belonging to Space group, the particle size is 100-300nm, and the particles are agglomerated together. The present invention mainly prepares vanadium-doped lithium nickel cobalt manganese oxide LiNi _{1/ 3} Co _1/3 Mn _1/3 O ₂ nanometer material, when it is used as the positive electrode active material of lithium ion battery, it shows the characteristics of high power and good cycle stability; secondly, the process of the present invention is simple, through simple and easy parallel flow The precursor slurry can be obtained by adding materials, and the slurry is centrifugally washed and dried and solid-phase sintered in an air atmosphere to obtain a vanadium-doped lithium nickel cobalt manganese oxide nanometer material. The method is highly feasible, easy to scale up, conforms to the characteristics of green chemistry, and is conducive to market promotion.

Description

Vanadium doped lithium nickel cobalt manganese oxide nanomaterial and its preparation method and application

technical field

The invention belongs to the technical field of nanometer material and electrochemistry, in particular to a preparation method of vanadium doped lithium nickel cobalt manganese oxide (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) nano material, which can be used as lithium ion Battery cathode active material.

Background technique

Today, in order to further promote the rapid development of the field of electric vehicles, the study of high-capacity, high-power, high-stability, good temperature adaptability and low-cost lithium-ion batteries based on new nanostructures is the frontier of lithium-ion battery research in the current low-carbon economy era and one of the hotspots. LiNi _1/3 Co _1/3 Mn _1/3 O ₂ combines the advantages of LiNiO ₂ , LiCoO ₂ and LiMnO ₂ to form a co-solution system of LiNiO ₂ /LiCoO ₂ /LiMnO ₂ , and there are obvious three meta-synergy. With the advantages of low price, easy synthesis, high theoretical capacity, stable electrochemical performance and good safety, it is considered to be one of the most potential cathode materials for lithium-ion batteries.

LiNi _1/3 Co _1/3 Mn _1/3 O ₂ has a layered structure of α-NaFeO ₂ and belongs to space group. Among them, Ni/Co/Mn mainly exist in the crystal lattice as 2+/3+/4+ respectively. During the charge and discharge process, Ni ²⁺ and Co ³⁺ are active substances participating in the electrochemical reaction, and Mn ⁴⁺ is inactive. The substance does not participate in the electrochemical reaction, but can improve the stability of the crystal structure while reducing the cost of the cathode material. By analyzing the mechanism that affects the electrochemical performance of the material and modifying it, the electrochemical performance of the product has been continuously improved. At present, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ has been put into practical use, but the practicality of the material However, there are still problems to be solved: (1) Since the radius of Ni ²⁺ is close to that of Li ⁺ , Ni ²⁺ is easy to enter the lithium site during synthesis, causing dislocations, resulting in low first discharge efficiency and relatively high first discharge capacity loss. (2) The diffusion coefficient of lithium ions is small, the capacity decays faster at high potentials, the charge and discharge performance at high currents is poor, and the thermodynamic stability of the compound after delithiation is not ideal, which is easy to cause oxygen deficiency and phase transition. In response to these problems, with the help of existing research results, relevant scholars have carried out extensive and detailed studies on bulk phase doping and surface coating modification of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ cathode materials.

Doping and modifying the positive electrode material can improve the structural stability of the material before and after charging and discharging, inhibit the phase transition, increase the degree of delithiation, increase the capacity of the material, and increase the conductivity of the material. According to the theory of crystal chemistry, sometimes a small amount of foreign component doping leads to crystal defects, which can increase the diffusion rate of ions in the bulk phase; according to the energy band theory, semiconductor compounds can be formed by doping with high or low valence ions to form p-type or n-type semiconductors. Thereby increasing the crystal conductivity. In recent years, researchers have explored the effect of different metal elements (Mg, Al, Zr, Ti, Na, Fe, Ru, etc.) on the electrochemical performance of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ cathode materials. influences. However, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanomaterials substituted with trace amounts of vanadium are rarely reported.

Contents of the invention

The technical problem to be solved by the present invention is to provide a kind of vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and preparation method thereof for the above-mentioned prior art, its technique is simple, conforms to The requirements of green chemistry and easy to scale up, on this basis, vanadium doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ also has excellent electrochemical performance.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: vanadium-doped lithium nickel cobalt manganese oxide nanomaterials have a layered structure of α-NaFeO ₂ and belong to The space group, whose particle size is 100-300nm, and the particles are agglomerated together, is a product obtained by the following method, comprising the following steps:

1) adding nickel sulfate, cobalt sulfate, and manganese sulfate to distilled water, stirring and dissolving to obtain a metal salt solution;

2) Weigh the carbonate precipitating agent with a metal salt molar ratio of 1:1, add it to distilled water to obtain a transparent solution, and stir evenly;

3) Take a small amount of concentrated ammonia water and dilute it as the bottom solution; under continuous magnetic stirring conditions, add the solution obtained in steps 1) and 2) dropwise to the ammonia solution in step 3) at the same time, and control the reaction pH value at 8.0;

4) Stir in a water bath at room temperature or 65°C for 24 to 72 hours to obtain a soil color paste, and dry it after centrifugal washing to obtain a precursor powder;

5) After pre-calcining the precursor powder in a muffle furnace, disperse and mix it with vanadium pentoxide and lithium source in alcohol, stir and dry to obtain powder;

6) The powder obtained in step 5) is slightly ground and then calcined to finally obtain a black vanadium-doped lithium nickel cobalt manganese oxide nanomaterial.

According to the above scheme, the carbonate precipitation agent described in step 2) is any one of Na ₂ CO ₃ and NH ₄ HCO ₃ or a mixture thereof.

According to the above scheme, the lithium source in step 3) is any one of LiAc, Li ₂ CO ₃ , LiNO ₃ , LiOH or a mixture thereof.

According to the above scheme, the calcining temperature in step 5) is 500°C and the time is 5 hours, and the calcining temperature in step 6) is 800-900°C and the time is 12-20 hours.

The preparation method of the vanadium-doped lithium nickel cobalt manganese oxide nanomaterial comprises the following steps:

1) adding nickel sulfate, cobalt sulfate, and manganese sulfate to distilled water, stirring and dissolving to obtain a metal salt solution;

2) Weigh the carbonate precipitating agent with a metal salt molar ratio of 1:1, add it to distilled water to obtain a transparent solution, and stir evenly;

3) Take a small amount of concentrated ammonia water and dilute it as the bottom solution; under continuous magnetic stirring conditions, add the solution obtained in steps 1) and 2) dropwise to the ammonia solution in step 3) at the same time, and control the reaction pH value at 8.0;

4) Stir in a water bath at room temperature or 65°C for 24 to 72 hours to obtain a soil color paste, and dry it after centrifugal washing to obtain a precursor powder;

5) After pre-calcining the precursor powder in a muffle furnace, disperse and mix it with vanadium pentoxide and lithium source in alcohol, stir and dry to obtain powder;

6) The powder obtained in step 5) is slightly ground and then calcined to finally obtain a black vanadium-doped lithium nickel cobalt manganese oxide nanomaterial.

The application of the vanadium-doped lithium-nickel-cobalt-manganese oxide nanometer material as the positive electrode active material of the lithium ion battery.

The vanadium-doped lithium-nickel-cobalt-manganese oxide electrode material of the invention has a short ion transmission path, a high ion diffusion rate and electronic conductivity. The substitution of vanadium leads to an increase in the content of trivalent Mn in the lattice, and the trivalent manganese ions improve the lattice stability and electronic conductivity through the change of the valence state during the charge and discharge process, which reduces the extreme electrode material generated during the rapid charge and discharge process. Finally, the application of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ electrode materials in the field of high-power and long-life electrode materials will be realized, making it a potential application material for lithium-ion batteries for electric vehicles.

The beneficial effects of the present invention are: the present invention mainly prepares vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nano material, when it is used as the positive electrode active material of lithium ion battery, it shows the characteristics of high power and good cycle stability; secondly, the process of the present invention is simple, and the precursor slurry can be obtained by simple and feasible co-current feeding, and the slurry The vanadium-doped lithium-nickel-cobalt-manganese oxide nanometer material can be obtained by performing centrifugal washing and drying and solid-phase sintering under air atmosphere. The method is highly feasible, easy to scale up, conforms to the characteristics of green chemistry, and is conducive to market promotion.

Description of drawings

Fig. 1 is the XRD figure of the vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material of the embodiment 1 of the present invention;

Fig. 2 is the SEM figure of the vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material of the embodiment 1 of the present invention;

Fig. 3 is the TEM figure of the vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material of the embodiment 1 of the present invention;

Fig. 4 is a diagram of the normal temperature battery cycle performance of the vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanomaterial in Example 1 of the present invention.

detailed description

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

Example 1:

The preparation method of vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material, it comprises the steps:

1) Add 2.6284g of nickel sulfate (NiSO ₄ ), 2.8115g of cobalt sulfate (CoSO ₄ ), 1.6395g of manganese sulfate (MnSO ₄ ) (Ni:Co:Mn=1:1:0.99) into 15mL of deionized water, at room temperature Stir and dissolve to obtain a wine red metal salt solution;

2) Weigh 3.1797g of sodium carbonate (Na ₂ CO ₃ ) (the molar ratio of sodium carbonate to metal salt is 1:1) and add it into 15mL of deionized water, stir and dissolve at room temperature to obtain a transparent precipitant solution;

3) Measure 0.42ml of concentrated ammonia water (NH ₃ ·H ₂ O) and add it to 20ml of deionized water for dilution. The ammonia solution is used as the bottom liquid. Add the metal salt solution and the precipitant solution in steps 1) and 2) at the same time, and control The pH of the reaction system was around 8.0, and a pink slurry was obtained after the sample was added dropwise;

4) After stirring in a water bath at 65°C for 48 hours, the soil color paste was obtained, which was washed by centrifugation and then dried to obtain the precursor powder;

5) The precursor powder was pre-fired in a muffle furnace at 500°C for 5 hours, and the obtained black powder was mixed with 0.0273g of vanadium pentoxide (V ₂ O ₅ ) and 1.2588g of lithium hydroxide (LiOH) in alcohol and dispersed evenly. Stir and dry at 80°C;

6) The black precursor powder doped with vanadium source and lithium source was slightly ground and then calcined at 800°C for 16 hours in an air atmosphere to finally obtain black vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _{1 /3} O ₂ nanomaterials.

Taking the vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nano material as an example, its structure is determined by X-ray diffractometer. As shown in Figure 1, the X-ray diffraction pattern (XRD) shows that the vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ phase has α-NaFeO ₂ layered structure, belongs to Space group, due to the small amount of doping elements, no heterophase peaks are observed in the XRD pattern.

SEM images (Fig. 2) and TEM images (Fig. 3) show that our prepared LiNi _1/3 Co _1/3 Mn _1/3 O ₂ is nano-sized particles. Individual vanadium-doped LiNi _1/3 Co _1/3 Mn _1/3 O ₂ particles have a size of 0.1-0.3 μm, and small particles aggregate together to form large particles with a size of tens of microns.

The vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ prepared by the invention is used as the positive active material of the lithium ion battery, and the remaining steps of the lithium ion battery preparation method are the same as the usual preparation method. The preparation method of the positive electrode sheet is as follows, using vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ as the active material, Super carbon as the conductive agent, and PVDF as the binder; firstly, 0.27 Dissolve gPVDF in 14.73g of N-methylpyrrolidone (NMP) to obtain a binder solution; weigh 210mg of active material and 60mg of Super carbon and grind them evenly, add 1.6667g of binder solution, grind for 5 minutes and evenly coat on aluminum foil , and then dried in an oven at 80°C for 24 hours before use. 1M LiPF ₆ dissolved in ethylene carbonate (EC) and dimethyl carbonate (DMC) was used as the electrolyte, the lithium sheet was used as the negative electrode, Celgard2325 was used as the diaphragm, and CR2025 stainless steel was used as the battery case to assemble a button-type lithium-ion battery.

Taking the vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ obtained in this embodiment as an example, as shown in Figure 4a, at 0.5C, 1C, 2C, 5C, 10C and At a current density of 20C, the initial discharge specific capacities of vanadium-doped LiNi _1/3 Co _1/3 Mn _1/3 O ₂ can reach 169.4, 161.1, 160.4, 149.9, 142.9 and 137.7mAh/g, respectively. The rate performance of the material is excellent (Figure 4b). After charging and discharging at different current densities from 0.5C to 20C, the discharge capacity of the material at a current density of 20C can still reach 136.6mAh/g. After undergoing the above-mentioned rapid charge and discharge, the capacity of the material at a current density of 0.5C can be recovered to 165.1mAh/g, indicating that the material has good structural stability. In addition, the cycle stability of the material is also very prominent (Figure 4c). At a current density of 1C, the specific capacity of the material after 1000 cycles is still 114mAh/g, the capacity retention rate is 70.8%, and the sub-capacity decay rate is 0.036%. . Most of the Coulombic efficiencies can reach 99% during the whole battery test, indicating the good cycle reversibility of the material. The above properties show that the vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanomaterial has very excellent electrochemical performance and is a potential cathode material for lithium ion batteries.

Example 2:

The preparation method of vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material, it comprises the steps:

1) Add 2.6284g of nickel sulfate (NiSO ₄ ), 2.8115g of cobalt sulfate (CoSO ₄ ), 1.6395g of manganese sulfate (MnSO ₄ ) (Ni:Co:Mn=1:1:0.99) into 15mL of deionized water, at room temperature Stir and dissolve to obtain a wine red metal salt solution;

2) Weigh 1.5899g of sodium carbonate (Na ₂ CO ₃ ) and 1.1859g of ammonium bicarbonate (NH ₄ HCO ₃ ) (Na ₂ CO ₃ :NH ₄ HCO ₃ :metal salt=1:1:2) and add to 15mL Dissolve in deionized water with stirring at room temperature to obtain a transparent precipitant solution;

3) Measure 0.42ml of concentrated ammonia water (NH ₃ ·H ₂ O) and add it to 20ml of deionized water for dilution. The ammonia solution is used as the bottom liquid. Add the metal salt solution and the precipitant solution in steps 1) and 2) at the same time, and control The pH of the reaction system was around 8.0, and a pink slurry was obtained after the sample was added dropwise;

4) After stirring in a water bath at 65°C for 48 hours, the soil color paste was obtained, which was washed by centrifugation and then dried to obtain the precursor powder;

5) The precursor powder was pre-fired in a muffle furnace at 500°C for 5 hours, and the obtained black powder was mixed with 0.0273g of vanadium pentoxide (V ₂ O ₅ ) and 1.2588g of lithium hydroxide (LiOH) in alcohol and dispersed evenly. Stir and dry at 80°C;

6) The black precursor powder mixed with vanadium source and lithium source was slightly ground and then calcined at 800°C for 16 hours in an air atmosphere to finally obtain black lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ Nanomaterials.

Taking the vanadium-doped LiNi _1/3 Co _1/3 Mn _1/3 O ₂ obtained in this example as an example, the first discharge specific capacity at 1C current density can reach 129mAh/g respectively, and the discharge specific capacity after 500 cycles It is 90.4mAh/g.

Example 3:

The preparation method of vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material, it comprises the steps:

1) Add 2.6284g of nickel sulfate (NiSO ₄ ), 2.8115g of cobalt sulfate (CoSO ₄ ), 1.6395g of manganese sulfate (MnSO ₄ ) (Ni:Co:Mn=1:1:0.99) into 15mL of deionized water, at room temperature Stir and dissolve to obtain a wine red metal salt solution;

2) Weigh 3.1797g of sodium carbonate (Na ₂ CO ₃ ) (the molar ratio of sodium carbonate to metal salt is 1:1) and add it into 15mL of deionized water, stir and dissolve at room temperature to obtain a transparent precipitant solution;

3) Measure 0.42ml of concentrated ammonia water (NH ₃ ·H ₂ O) and add it to 20ml of deionized water for dilution. The ammonia solution is used as the bottom liquid. Add the metal salt solution and the precipitant solution in steps 1) and 2) at the same time, and control The pH of the reaction system was around 8.0, and a pink slurry was obtained after the sample was added dropwise;

4) After stirring at room temperature for 48 hours, the soil color paste was obtained, which was centrifuged and washed and then dried to obtain the precursor powder;

5) The precursor powder was pre-fired in a muffle furnace at 500°C for 5 hours, and the obtained black powder was mixed with 0.0273g of vanadium pentoxide (V ₂ O ₅ ) and 1.2588g of lithium hydroxide (LiOH) in alcohol and dispersed evenly. Stir and dry at 80°C;

6) The black precursor powder mixed with vanadium source and lithium source was slightly ground and then calcined at 800°C for 16 hours in an air atmosphere to finally obtain black lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ Nanomaterials.

Taking the vanadium-doped LiNi _1/3 Co _1/3 Mn _1/3 O ₂ obtained in this example as an example, the first discharge specific capacity at a current density of 1C can reach 145.8mAh/g respectively, and the discharge specific capacity after 500 cycles The capacity is 94.3mAh/g.

Example 4:

The preparation method of vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material, it comprises the steps:

1) Add 2.6284g of nickel sulfate (NiSO ₄ ), 2.8115g of cobalt sulfate (CoSO ₄ ), 1.6395g of manganese sulfate (MnSO ₄ ) (Ni:Co:Mn=1:1:0.99) into 15mL of deionized water, at room temperature Stir and dissolve to obtain a wine red metal salt solution;

2) Weigh 3.1797g of sodium carbonate (Na ₂ CO ₃ ) (the molar ratio of sodium carbonate to metal salt is 1:1) and add it into 15mL of deionized water, stir and dissolve at room temperature to obtain a transparent precipitant solution;

3) Measure 0.42ml of concentrated ammonia water and add it to 20ml of deionized water for dilution. The ammonia solution is used as the bottom liquid. Add the metal salt solution and the precipitant solution in steps 1) and 2) at the same time, and control the pH of the reaction system at about 8.0. Samples After the dropwise addition, a pink slurry was obtained;

4) After stirring in a water bath at 65°C for 48 hours, the soil color paste was obtained, which was washed by centrifugation and then dried to obtain the precursor powder;

5) The precursor powder was pre-fired in a muffle furnace at 500°C for 5 hours, and the obtained black powder was mixed with 0.0273g of vanadium pentoxide (V ₂ O ₅ ) and 1.2588g of lithium hydroxide (LiOH) in alcohol and dispersed evenly. Stir and dry at 80°C;

6) The black precursor powder mixed with vanadium source and lithium source was slightly ground and then calcined at 850°C for 16 hours in an air atmosphere to finally obtain black lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ Nanomaterials.

Taking the vanadium-doped LiNi _1/3 Co _1/3 Mn _1/3 O ₂ obtained in this example as an example, the first discharge specific capacity at a current density of 0.5C can reach 153.5mAh/g respectively, and the discharge after 300 cycles The specific capacity is 116.2mAh/g.

Example 5:

The preparation method of vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material, it comprises the steps:

1) Add 2.6284g of nickel sulfate (NiSO ₄ ), 2.8115g of cobalt sulfate (CoSO ₄ ), 1.6395g of manganese sulfate (MnSO ₄ ) (Ni:Co:Mn=1:1:0.99) into 15mL of deionized water, at room temperature Stir and dissolve to obtain a wine red metal salt solution;

2) Weigh 3.1797g of sodium carbonate (Na ₂ CO ₃ ) (the molar ratio of sodium carbonate to metal salt is 1:1) and add it into 15mL of deionized water, stir and dissolve at room temperature to obtain a transparent precipitant solution;

3) Measure 0.42ml of concentrated ammonia water (NH ₃ ·H ₂ O) and add it to 20ml of deionized water for dilution. The ammonia solution is used as the bottom liquid. Add the metal salt solution and the precipitant solution in steps 1) and 2) at the same time, and control The pH of the reaction system was around 8.0, and a pink slurry was obtained after the sample was added dropwise;

4) After stirring in a water bath at 65°C for 48 hours, the soil color paste was obtained, which was washed by centrifugation and then dried to obtain the precursor powder;

5) The precursor powder was pre-fired in a muffle furnace at 500°C for 5 hours, and the obtained black powder was mixed with 0.0273g of vanadium pentoxide (V ₂ O ₅ ) and 1.2588g of lithium hydroxide (LiOH) in alcohol and dispersed evenly. Stir and dry at 80°C;

6) The black precursor powder mixed with vanadium source and lithium source was slightly ground and then calcined at 900°C for 16 hours in an air atmosphere to finally obtain black lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ Nanomaterials.

Taking the vanadium-doped LiNi _1/3 Co _1/3 Mn _1/3 O ₂ obtained in this example as an example, the first discharge specific capacity at a current density of 0.5C can reach 162.2mAh/g, respectively, and discharge after 300 cycles The specific capacity is 119.5mAh/g.

Embodiment 6:

The preparation method of 2% vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material, it comprises the steps:

1) Add 2.6284g of nickel sulfate (NiSO ₄ ), 2.8115g of cobalt sulfate (CoSO ₄ ), 1.5889g of manganese sulfate (MnSO ₄ ) (Ni:Co:Mn=1:1:0.98) into 15mL of deionized water, at room temperature Stir and dissolve to obtain a wine red metal salt solution;

2) Weigh 3.1797g of sodium carbonate (Na ₂ CO ₃ ) (the molar ratio of sodium carbonate to metal salt is 1:1) and add it into 15mL of deionized water, stir and dissolve at room temperature to obtain a transparent precipitant solution;

3) Measure 0.42ml of concentrated ammonia water (NH ₃ ·H ₂ O) and add it to 20ml of deionized water for dilution. The ammonia solution is used as the bottom liquid. Add the metal salt solution and the precipitant solution in steps 1) and 2) at the same time, and control The pH of the reaction system was around 8.0, and a pink slurry was obtained after the sample was added dropwise;

4) After stirring in a water bath at 65°C for 48 hours, the soil color paste was obtained, which was washed by centrifugation and then dried to obtain the precursor powder;

5) The precursor powder was pre-fired in a muffle furnace at 500°C for 5 hours, and the obtained black powder was mixed with 0.0546g of vanadium pentoxide (V ₂ O ₅ ) and 1.2588g of lithium hydroxide (LiOH) in alcohol and dispersed evenly. Stir and dry at 80°C;

6) The black precursor powder doped with vanadium source and lithium source was slightly ground and then calcined at 800°C in an air atmosphere for 16 hours, and finally black lithium nickel cobalt manganese oxide LiNi _1/3 Co with a black vanadium doping content of 2% was obtained. _1/3 Mn _1/3 O ₂ nanomaterials.

Taking the vanadium-doped LiNi _1/3 Co _1/3 Mn _1/3 O ₂ obtained in this example as an example, the first discharge specific capacity at 1C current density can reach 163.4mAh/g respectively, and the discharge specific capacity after 300 cycles The capacity is 120.2mAh/g.

Embodiment 7:

The preparation method of 3% vanadium-doped lithium nickel cobalt manganese oxide LiNi _1/3 Co _1/3 Mn _1/3 O ₂ nanometer material, it comprises the steps:

1) Add 2.6284g nickel sulfate (NiSO ₄ ), 2.8115g cobalt sulfate (CoSO ₄ ), 1.5381g manganese sulfate (MnSO ₄ ) (Ni:Co:Mn=1:1:0.97) into 15mL deionized water, Stir and dissolve to obtain a wine red metal salt solution;

2) Weigh 3.1797g of sodium carbonate (Na ₂ CO ₃ ) (the molar ratio of sodium carbonate to metal salt is 1:1) and add it into 15mL of deionized water, stir and dissolve at room temperature to obtain a transparent precipitant solution;

3) Measure 0.42ml of concentrated ammonia water (NH ₃ ·H ₂ O) and add it to 20ml of deionized water for dilution. The ammonia solution is used as the bottom liquid. Add the metal salt solution and the precipitant solution in steps 1) and 2) at the same time, and control The pH of the reaction system was around 8.0, and a pink slurry was obtained after the sample was added dropwise;

4) After stirring in a water bath at 65°C for 48 hours, the soil color paste was obtained, which was washed by centrifugation and then dried to obtain the precursor powder;

5) The precursor powder was pre-fired in a muffle furnace at 500°C for 5 hours, and the obtained black powder was mixed with 0.0819g of vanadium pentoxide (V ₂ O ₅ ) and 1.2588g of lithium hydroxide (LiOH) in alcohol and dispersed evenly. Stir and dry at 80°C;

6) The black precursor powder mixed with vanadium source and lithium source was slightly ground and then calcined at 800°C for 16 hours in an air atmosphere, and finally obtained black lithium nickel cobalt manganese oxide LiNi _1/3 Co with 3% black vanadium doping _1/3 Mn _1/3 O ₂ nanomaterials.

Taking the vanadium-doped LiNi _1/3 Co _1/3 Mn _1/3 O ₂ obtained in this example as an example, the first discharge specific capacity at a current density of 1C can reach 148.2mAh/g, and the discharge specific capacity after 300 cycles The capacity is 117.4mAh/g.

Claims (9)

1. vanadium doping lithium nickel cobalt manganese oxide nano material, has α-NaFeO ₂layer structure, belongs to R3 ^_m space group, its granular size is 100-300nm, and reunites together between particle, and it is following method products therefrom, includes following steps:

1) join in distilled water by nickelous sulfate, cobaltous sulfate, manganese sulfate, stirring and dissolving, obtains metal salt solution;

2) taking with slaine mol ratio is the carbonate deposition agent of 1:1, is joined in distilled water and obtains clear solution, stir;

3) measure a small amount of concentrated ammonia liquor dilution after as end liquid; Under continuing magnetic force stirring condition, by step 1) and 2) gained solution is added drop-wise to step 3 simultaneously) in ammonia spirit in, control pH value in reaction 8.0;

4) obtain earth mill base body after normal temperature or 65 DEG C of stirring in water bath 24 ~ 72h, centrifuge washing post-drying obtains precursor powder;

5) by precursor powder in Muffle furnace after pre-burning, disperse to mix in alcohol with vanadic oxide and lithium source, stirring and drying obtains powder;

6) by step 5) powder that obtains calcines after grinding a little again, finally obtains the vanadium doping lithium nickel cobalt manganese oxide nano material of black.

2. vanadium doping lithium nickel cobalt manganese oxide nano material according to claim 1, is characterized in that, step 2) described in carbonate deposition agent be Na ₂cO ₃and NH ₄hCO ₃in the mixing of any one or they.

3. vanadium doping lithium nickel cobalt manganese oxide nano material according to claim 1, is characterized in that, step 3) described in lithium source be LiAc, Li ₂cO ₃, LiNO ₃, any one or they in LiOH mixing.

4. vanadium doping lithium nickel cobalt manganese oxide nano material according to claim 1, is characterized in that, step 5) described in calcined temperature be 500 DEG C, the time is 5 hours, step 6) described in calcining heat be 800-900 DEG C, the time is 12 ~ 20 hours.

5. the preparation method of vanadium doping lithium nickel cobalt manganese oxide nano material according to claim 1, includes following steps:

1) join in distilled water by nickelous sulfate, cobaltous sulfate, manganese sulfate, stirring and dissolving, obtains metal salt solution;

2) taking with slaine mol ratio is the carbonate deposition agent of 1:1, is joined in distilled water and obtains clear solution, stir;

3) measure a small amount of concentrated ammonia liquor dilution after as end liquid; Under continuing magnetic force stirring condition, by step 1) and 2) gained solution is added drop-wise to step 3 simultaneously) in ammonia spirit in, control pH value in reaction 8.0;

4) obtain earth mill base body after normal temperature or 65 DEG C of stirring in water bath 24 ~ 72h, centrifuge washing post-drying obtains precursor powder;

5) by precursor powder in Muffle furnace after pre-burning, disperse to mix in alcohol with vanadic oxide and lithium source, stirring and drying obtains powder;

6) by step 5) powder that obtains calcines after grinding a little again, finally obtains the vanadium doping lithium nickel cobalt manganese oxide nano material of black.

6. the preparation method of vanadium doping lithium nickel cobalt manganese oxide nano material according to claim 5, is characterized in that, step 2) described in carbonate deposition agent be Na ₂cO ₃and NH ₄hCO ₃in the mixing of any one or they.

7. the preparation method of vanadium doping lithium nickel cobalt manganese oxide nano material according to claim 5, is characterized in that, step 3) described in lithium source be LiAc, Li ₂cO ₃, LiNO ₃, any one or they in LiOH mixing.

8. the preparation method of vanadium doping lithium nickel cobalt manganese oxide nano material according to claim 5, it is characterized in that, step 5) described in calcined temperature be 500 DEG C, the time is 5 hours, step 6) described in calcining heat be 800-900 DEG C, the time is 12 ~ 20 hours.

9. vanadium doping lithium nickel cobalt manganese oxide nano material according to claim 1 is as the application of anode active material of lithium ion battery.