Preparation and application of nickel vanadate / carbon nanotube composite nanospheres

Abstract

The application discloses a preparation method and application of a nickel vanadate / carbon nanotube composite nanosphere. NiCl2.6H2O and nickel-plated carbon nanotubes are added into an ammonium metavanadate solution, and then anhydrous ethanol is slowly added. The mixture is heated at a temperature of 160-200 DEG C for 6-10 hours. The mixture is centrifuged and the precipitate is dried to obtain the nickel vanadate / carbon nanotube composite nanosphere. The nickel vanadate / carbon nanotube composite nanosphere is synthesized by a one-step hydrothermal method for the first time, and has high dispersion and uniform particle size. The unique CNT winding main body structure can provide an electrically conductive path for electron transmission. The ultra-small nickel vanadate nanoparticles are uniformly embedded on the CNT, which accelerates electron transmission and greatly reduces the transmission distance of lithium ions, and improves the electrochemical performance of the nickel vanadate / CNT composite nanosphere. The nickel vanadate / CNT lithium ion battery negative electrode material prepared by the method has good cycle stability and rate performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nanocomposites and its application, and particularly relates to preparation of nickel vanadate / carbon nanotube (Ni3V2O8 / CNT) composite nanospheres and application thereof in lithium ion batteries. BACKGROUND

[0002] Industrial graphite has been widely used in lithium ion battery negative electrodes, but due to its low specific capacity (372 mA h g -1 ), its further application in lithium ion batteries is limited. Therefore, exploring new high-energy, high-power-density lithium ion battery negative electrode materials and improving their electrochemical performance are currently one of the important research directions of lithium ion batteries.

[0003] The transition metal vanadate materials have high electrode specific capacity due to the multiple valence of vanadium in the materials, and are also beneficial to the application of batteries in a wider potential range. Therefore, metal vanadate is considered as an anode material with development potential for lithium-ion batteries. Among them, nickel vanadate electrode material has high specific capacity, excellent rate performance, environmental friendliness and other advantages. At the same time, the price of nickel is only one third of that of cobalt, and the cost is low, so it is a new type of lithium-ion battery anode material with great application prospect. [LU Y, NAI J W, LOU X W. Formation of NiCo2V2O8 yolk-doubleshell spheres with enhanced lithium storage properties. Angewandte Chemie International Edition, 2018, 57(11): 2899-2903; YANG G Z, LI S Y, WU M M, et al. Zinc pyrovanadate nanosheets of atomic thickness: excellent Li-storage properties and investigation of their electrochemical mechanism. Journal of Materials Chemistry A, 2016, 4(28): 10974-10985.] However, nickel vanadate as a lithium-ion battery anode material also has some shortcomings in practical application. The conductivity of metal vanadate material is poor, and the volume expands greatly during charging and discharging, which is easy to pulverize, leading to the detachment of active material from the current collector, and thus significantly affecting the cycle stability. And the specific surface area of the prepared metal vanadate material is not high, which affects its electrochemical performance. In order to solve the above inherent shortcomings of nickel vanadate and improve the electrochemical performance of nickel vanadate as a lithium-ion battery anode material, researchers have focused on the micro-nano, surface coating and composite of nickel vanadate electrode material in recent years. Special nanostructure can inhibit the volume effect during charging and discharging, and improve the cycle stability of electrode material, such as hollow sphere, porous and ultrafine particle morphology, especially ultrafine nanoparticles, which have extraordinary performance due to their ultra-small particle size.Among many carbon-based materials, carbon nanotubes as one-dimensional nanomaterials, light weight, tube wall hexagonal structure perfect connection, have many abnormal mechanical, electrical and chemical properties [WANG C, FANG D, WANG H E, et al. Uniform nickel vanadate (Ni3V2O8) nanowire arrays organized by ultrathin nanosheets with enhanced lithium storage properties. Scientific Reports, 2016, 6: 20826- 20834; SAMBANDAM B, SOUNDHARRAJAN V, SONG J, et al. Ni3V2O8 nanoparticles as an excellent anode material for high-energy lithium-ion batteries. Journal of Electroanalytical Chemistry, 2018, 810: 34-40; SOUNDHARRAJAN V, SAMBANDAM B, SONG J, et al. Bitter gourd-shaped Ni3V2O8 anode developed by a one-pot metal-organic framework-combustion technique for advanced Li-ion batteries. Ceramics International, 2017, 43(16): 13224-13232.]. How to combine carbon nanotubes with ultrafine nickel vanadate nanoparticles, find a simple and controllable method, to alleviate the volume expansion / contraction phenomenon caused by electrode material aggregation powder off, to improve the cycle stability of nickel vanadate electrode material has important significance. SUMMARY

[0004] The purpose of the application is to provide a kind of nickel vanadate / carbon nanotube composite nanosphere Ni3V2O8 / CNT and its application in lithium ion battery, the nickel vanadate / carbon nanotube composite nanosphere prepared by using the method has the characteristics such as good dispersibility, large specific capacity, good cycle performance and long service life.

[0005] A kind of nickel vanadate / carbon nanotube composite nanosphere is prepared by the following method, it includes:

[0006] 1) 300-500 mg of ammonium metavanadate powder was added to 30-50 mL of deionized water, heated to 60-80 °C, stirred, dissolved, and then cooled to room temperature;

[0007] 2) 30-60 mg of NiCl2·6H2O and 500-800 mg of nickel-plated carbon nanotubes were weighed and added to the ammonium metavanadate solution obtained in step 1), stirred for 10-20 min, and then 50-70 mL of anhydrous ethanol was slowly added to the above solution and stirred until uniform;

[0008] 3) The mixed solution obtained in step 2) was heated at a temperature of 160-200 °C for 6-10 h; centrifuged, the precipitate was dried, and Ni3V2O8 / CNT composite nanospheres were obtained.

[0009] The drying in step 3) was performed in a 50-70 °C oven for 10-20 h;

[0010] The centrifugation in step 3) was performed at 5000-6000 rpm for 5-7 min.

[0011] In step 1), the ammonium metavanadate was 300 mg and the deionized water was 30 mL;

[0012] In step 2), the NiCl2·6H2O was 30 mg, the nickel-plated carbon nanotubes were 500 mg, and the anhydrous ethanol was 50 mL;

[0013] In step 3), the temperature was 170 °C and the heating time was 10 h.

[0014] In step 1), the ammonium metavanadate was 500 mg and the deionized water was 50 mL;

[0015] In step 2), the NiCl2·6H2O was 60 mg, the nickel-plated carbon nanotubes were 800 mg, and the anhydrous ethanol was 70 mL;

[0016] In step 3), the temperature was 180 °C and the heating time was 6 h.

[0017] In step 1), the ammonium metavanadate was 400 mg and the deionized water was 40 mL;

[0018] In step 2), the NiCl2·6H2O was 50 mg, the nickel-plated carbon nanotubes were 600 mg, and the anhydrous ethanol was 60 mL;

[0019] In step 3), the temperature was 190 °C and the heating time was 6 h.

[0020] The application provides a preparation method and application of a nickel vanadate / carbon nanotube composite nanosphere, which comprises the following steps: adding NiCl2.6H2O and nickel-plated carbon nanotubes into an ammonium metavanadate solution, then slowly adding anhydrous ethanol, heating at a temperature of 160-200 DEG C for 6-10 h, and centrifugally separating and drying the precipitate. The Ni3V2O8 / CNT composite nanosphere with high dispersion and uniform particle size is synthesized by a one-step hydrothermal method for the first time. The unique CNT-wrapped main structure can provide an electrically conductive path for electron transmission. The ultra-small Ni3V2O8 nanoparticles are uniformly embedded on the CNT, which accelerates electron transmission and greatly reduces the transmission distance of lithium ions, thereby improving the electrochemical performance of the Ni3V2O8 / CNT composite nanosphere. The Ni3V2O8 / CNT lithium ion battery negative electrode material prepared by the method has good cycle stability and rate performance.

[0021] The application has the following advantages:

[0022] 1) The synthesis method is simple, and the Ni3V2O8 / CNT composite nanosphere with high dispersion and uniform particle size is synthesized by a one-step hydrothermal method for the first time.

[0023] 2) The CNT-wrapped main structure can provide an electrically conductive path for electron transmission and accelerate electrochemical reaction kinetics.

[0024] 3) The ultra-small Ni3V2O8 nanoparticles are uniformly embedded on the CNT, which accelerates electron transmission and greatly reduces the transmission distance of lithium ions, thereby improving the electrochemical performance of the Ni3V2O8 / CNT composite nanosphere.

[0025] 4) The Ni3V2O8 / CNT composite nanomaterial prepared by the method has high capacity and good cycle stability. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A transmission electron microscope picture of the nickel-plated CNT prepared in Example 1 of the application;

[0027] Figure 2 A scanning electron microscope picture of the Ni3V2O8 / CNT composite nanosphere prepared in Example 1 of the application;

[0028] Figure 3 A transmission electron microscope picture of a single Ni3V2O8 / CNT composite nanosphere prepared in Example 1 of the application;

[0029] Figure 4 A face scanning picture of the Ni3V2O8 / CNT composite nanosphere prepared in Example 1 of the application;

[0030] Figure 5The charge-discharge cycle curves of the Ni3V2O8 / CNT composite nanomaterial prepared in Embodiment 1 under different current densities are shown in FIG. 1. DETAILED DESCRIPTION

[0031] Embodiment 1

[0032] A nickel vanadate / carbon nanotube composite nanosphere Ni3V2O8 / CNT

[0033] Ammonium metavanadate powder of 300 mg was added to 30 mL of deionized water, and the mixture was placed in a 60 ℃ oil bath for heating and stirring for 5 min. After the solid powder was completely dissolved, the mixture was cooled to room temperature for standby. 30 mg of NiCl2·6H2O and 500 mg of nickel-plated carbon nanotubes (3A, item number: A60059, CAS: 308068-56-6) were weighed and added to the above solution, respectively. After stirring at room temperature for 10 min, 50 mL of anhydrous ethanol was slowly added to the above solution, and the mixture was stirred and mixed uniformly. Subsequently, the mixed solution was transferred to an autoclave, and the autoclave was heated at 170 ℃ for 10 h. After centrifugal separation (speed: 5000 rpm, time: 7 min) and oven drying (temperature: 50 ℃ , time: 20 h), the Ni3V2O8 / CNT composite nanospheres were obtained.

[0034] Embodiment 2

[0035] A nickel vanadate / carbon nanotube composite nanosphere Ni3V2O8 / CNT

[0036] Ammonium metavanadate powder of 500 mg was added to 50 mL of deionized water, and the mixture was placed in a 75 ℃ oil bath for heating and stirring for 5 min. After the solid powder was completely dissolved, the mixture was cooled to room temperature for standby. 60 mg of NiCl2·6H2O and 800 mg of nickel-plated carbon nanotubes were weighed and added to the above solution, respectively. After stirring at room temperature for 20 min, 70 mL of anhydrous ethanol was slowly added to the above solution, and the mixture was stirred and mixed uniformly. Subsequently, the mixed solution was transferred to an autoclave, and the autoclave was heated at 180 ℃ for 6 h. After centrifugal separation (speed: 6000 rpm, time: 6 min) and oven drying (temperature: 70 ℃ , time: 10 h), the Ni3V2O8 / CNT composite nanospheres were obtained.

[0037] Embodiment 3

[0038] A nickel vanadate / carbon nanotube composite nanosphere Ni3V2O8 / CNT

[0039] Add 400 mg of ammonium metavanadate powder to 40 mL of deionized water, and place the mixture at 80 °C. ℃ The mixture was heated and stirred in an oil bath for 6 minutes until the solid powder was completely dissolved, then cooled to room temperature for later use. 40 mg of NiCl₂·6H₂O and 600 mg of nickel-plated carbon nanotubes were weighed and added sequentially to the above solution. After stirring at room temperature for 15 minutes, 60 mL of anhydrous ethanol was slowly added to the solution, and the mixture was stirred until homogeneous. The resulting solution was then transferred to an autoclave and heated at 190°C. ℃ Heating for 6 hours. Then centrifuging (7000 rpm, 5 min) and drying (temperature: 50°C). ℃ After 12 h, Ni3V2O8 / CNT composite nanospheres were obtained.

[0040] Experimental Example

[0041] Example 1 prepared a nickel vanadate / carbon nanotube composite nanosphere NNi3V2O8 / CNT composite nanomaterial for use in lithium-ion batteries.

[0042] Three materials were selected: Ni3V2O8 / CNT composite nanospheres, a conductive agent (SuperP), and a binder (PVDF). They were weighed according to a ratio of m1:m2:m3 = 8:1:1. An appropriate amount of N-methylpyrrolidone solution was added, and the mixture was stirred thoroughly. This mixture was then coated onto a pre-cut copper-coated foil and placed horizontally at 120°C. ℃ The drying time was set to 12 hours in a vacuum oven, and then the cells were punched into round electrode sheets using a button cell slicing machine for later use.

[0043] The assembly of the button cells was carried out in a glove box filled with high-purity Ar, with O2 < 0.1 ppm and H2O < 0.1 ppm controlled. First, the negative electrode shell was placed on a horizontal platform, and the negative electrode sheet was placed in the center of the electrode shell. Electrolyte was added to the center of the electrode sheet, and then the separator was placed over the electrode sheet. The separator needed to be wetted with electrolyte. Lithium sheets, gaskets, and springs were placed on the separator. After the positive electrode shell was covered, the sheets were pressed and transferred outside the glove box.

[0044] Experiments show that the prepared Ni3V2O8 / CNT composite nanomaterials possess high capacity and good cycling stability. Figure 5 As shown, in 1 Ag -1 10 A g -1 and 20 A g -1 After 500 charge-discharge cycles at the specified rate, the capacity was 880.4 mA hg. -1 490.9 mA hg -1 and 316.1 mA hg -1 .

Claims

1. A kind of nickel vanadate / carbon nanotube composite nanosphere, it is prepared by the following method, it includes: 1) 300-500 mg of ammonium metavanadate powder is added to 30-50 mL deionized water, heated to 60-80 ℃, stirring, after dissolving, cooling to room temperature; 2) 30-60 mg NiCl2 6H2O and 500-800 mg nickel-plated carbon nanotube are weighed and added to the ammonium metavanadate solution obtained in step 1) in turn, after stirring for 10-20 min, 50-70 mL of anhydrous ethanol is slowly added to the above solution, and stirred to mix uniformly; 3) the mixed solution obtained in step 2) is heated at a temperature of 160-200 ℃ for 6-10 h; Centrifugal separation, precipitate drying, to obtain Ni3V2O8 / CNT composite nanosphere. 2.The nickel vanadate / carbon nanotube composite nanosphere according to claim 1, characterized in that: The drying in step 3) is dried in a 50-70 ℃ oven for 10-20 h. 3.The nickel vanadate / carbon nanotube composite nanosphere according to claim 2, characterized in that: The centrifugation in step 3) is 5000-6000 rpm for 5-7 min.

4. The nickel vanadate / carbon nanotube composite nanosphere according to claim 1, 2 or 3, characterized in that: In step 1), the ammonium metavanadate is 300 mg, and the deionized water is 30 mL; In step 2), the NiCl2 6H2O is 30 mg, the nickel-plated carbon nanotube is 500 mg, and the anhydrous ethanol is 50 mL; In step 3), the temperature is 170 ℃, and the heating time is 10 h.

5. The nickel vanadate / carbon nanotube composite nanosphere according to claim 1, 2 or 3, characterized in that: In step 1), the ammonium metavanadate is 500 mg, and the deionized water is 50 mL; In step 2), the NiCl2 6H2O is 60 mg, the nickel-plated carbon nanotube is 800 mg, and the anhydrous ethanol is 70 mL; In step 3), the temperature is 180 ℃, and the heating time is 6 h.

6. The nickel vanadate / carbon nanotube composite nanosphere according to claim 1, 2 or 3, characterized in that: In step 1), the ammonium metavanadate is 400 mg, and the deionized water is 40 mL; In step 2), the NiCl2 6H2O is 50 mg, the nickel-plated carbon nanotube is 600 mg, and the anhydrous ethanol is 60 mL; In step 3), the temperature is 190 ℃, and the heating time is 6 h.

Images