阅读说明：本技术 一种基于碘掺杂石墨烯包裹的分级孔普鲁士蓝纳米球及其制备方法和应用 (hierarchical-pore Prussian-blue nanospheres wrapped by iodine-doped graphene as well as preparation method and application of nanospheres ) 是由 刘丹 张新民 王严杰 于 2019-10-29 设计创作，主要内容包括：本发明提供一种基于碘掺杂石墨烯包裹的分级孔普鲁士蓝纳米球及其制备方法和应用,其采用在不同温度下,向FeFe(CN)<Sub>6</Sub>纳米球前驱体加入无机酸进行刻蚀反应,制备出具有中空分级孔结构的FeFe(CN)<Sub>6</Sub>纳米球,并通过超声、冷冻复合干燥的工艺,加入碘掺杂石墨烯进行均匀致密包覆,得到掺杂石墨烯包裹的分级孔普鲁士蓝纳米球(即FeFe(CN)<Sub>6</Sub>@IG)。通过本制备方法,可以进一步增加中空分级孔FeFe(CN)<Sub>6</Sub>纳米球的导电性能,并且能够提高多次充放电后仍保持较好的性能。由该材料制备的锂离子电池负极极材料,具有较好的容量,稳定循环性好,容量维持率高达90％以上,并且该制备方法工艺简单,操作方便,适合大规模工业化生产。(The invention provides hierarchical pore Prussian blue nanospheres coated on basis of iodine-doped graphene as well as a preparation method and application thereof 6 Adding inorganic acid into the nanosphere precursor for etching reaction to prepare FeFe (CN) with a hollow hierarchical pore structure 6 Nanospheres are added with iodine-doped graphene for uniform and dense coating through the ultrasonic and freezing composite drying process to obtain doped grapheneHetero-graphene-encapsulated hierarchical pore prussian blue nanospheres (i.e., fefe (cn)) 6 @ IG) by the preparation method, steps can be further added to form hollow grading holes FeFe (CN) 6 The nanosphere has the conductive performance, and can improve the performance of the nanosphere after multiple charging and discharging. The lithium ion battery cathode material prepared from the material has good capacity, good stable cyclicity, capacity maintenance rate of more than 90 percent, simple preparation method process and convenient operation, and is suitable for large-scale industrial production.)

1, preparation methods of hierarchical pore Prussian blue nanospheres wrapped on iodine-doped graphene, which comprise the following steps:

A. will K₃[Fe(CN)₆]Dissolving in deionized water, adding surfactant, ultrasonic stirring to obtain clear solution, adding inorganic acid solution, stirring, heating, magnetically stirring, heating to 70-90 deg.C, reacting for 22-26 hr, and cooling to room temperature; centrifuging to collect precipitate, washing with distilled water and ethanol several times, and vacuum drying at 50-70 deg.C for 10-14 h to obtain solid FeFe (CN)₆A nanosphere precursor;

B. solid FeFe (CN) prepared above₆Mixing the nanosphere precursor and a surfactant, adding the mixture into an inorganic acid solution, uniformly stirring, heating to 120 ℃ in a sealed environment, continuously reacting for 4-6h, and gradually cooling to room temperature to obtain FeFe (CN) with graded pores₆Nanospheres;

C. iodine doped graphene and the prepared FeFe (CN) with graded pores₆Adding the nanosphere into ionized water, performing ultrasonic treatment for 1-2h, and freeze-drying for 46-50h to obtain iodine-doped graphene-coated hierarchical pore FeFe (CN)₆Nanospheres.

2. The method for preparing graded-pore Prussian-blue nanospheres based on iodine-doped graphene coating according to claim 1, wherein in step A, K is₃[Fe(CN)₆]And the amount of surfactantThe ratio is 1:15-1:30, and the concentration of the inorganic acid solution is 0.5M.

3. The method for preparing graded-pore prussian blue nanospheres based on iodine-doped graphene coating according to claim 2, wherein in step B, solid FeFe (CN)₆The mass ratio of the nanosphere precursor to the surfactant is 1:3-1:5, the concentration of the inorganic acid solution is 1.0-2.0M, the reaction time of temperature rise is 4.5-5h, the temperature rise rate is 2-5 ℃/min, the temperature drop rate is 0.2-2 ℃/min, and the nanosphere precursor and the surfactant have hierarchical pores FeFe (CN)₆The particle size of the nanosphere is 100-200 nm.

4. The preparation method of graded-pore Prussian-blue nanospheres based on iodine-doped graphene wrapping according to claim 3, wherein the surfactant is any of polyvinylpyrrolidone, cetyl trimethyl ammonium bromide or polyvinylidene fluoride.

5. The method for preparing graded-hole Prussian-blue nanospheres based on iodine-doped graphene wrapping according to claim 3, wherein the inorganic acid solution is any of hydrochloric acid, sulfuric acid and nitric acid.

6. The method for preparing Prussian blue nanospheres based on iodine-doped graphene wrapping classification holes according to claim 3, wherein in step C, the iodine-doped graphene and the Prussian blue nanospheres with classification holes are FeFe (CN)₆The mass ratio of the nanospheres is 1:5-1:10, ultrasonic treatment is carried out for 1.0-1.5h, and freeze drying is carried out for 48-50 h.

7. The preparation method of graded-pore prussian blue nanospheres based on iodine-doped graphene coating according to claim 3, which comprises the following steps:

a1, mixing K₃[Fe(CN)₆]Dissolving in deionized water, adding polyvinylpyrrolidone, ultrasonic stirring to obtain clear solution, adding HCl solution, stirring, heating to 80 deg.C under magnetic stirring, reacting for 24 hr,then cooling to room temperature; the precipitate was collected by centrifugation, washed several times with distilled water and ethanol and dried under vacuum at 60 ℃ for 12h to obtain solid FeFe (CN)₆A nanosphere precursor;

b1, solid FeFe (CN) prepared by the above method₆Respectively adding the nanosphere precursor and the surfactant into an inorganic acid solution, uniformly stirring, carrying out programmed heating to 120 ℃ in a sealed environment, continuously reacting for 5 hours, and gradually carrying out programmed cooling to room temperature to obtain FeFe (CN) with graded pores₆Nanospheres;

c1, doping iodine with graphene and FeFe (CN) with hierarchical pore prepared by the method₆Adding the nanosphere into ionized water, performing ultrasonic treatment for 1.5h, and freeze-drying for 48h to obtain the iodine-doped graphene-coated hierarchical pore FeFe (CN)₆Nanospheres.

8, graded-pore prussian blue nanospheres based on iodine-doped graphene wrapping prepared by the method of claims 1-6- , characterized in that the iodine-doped graphene wrapping graded-pore fefe (cn)₆The nanosphere is a dark blue powder structure, and the spherical particle size is 150-200 nm.

applications of iodine doped graphene coated based hierarchical pore prussian blue nanospheres according to claim 8, characterized in that said iodine doped graphene coated based hierarchical pore fefe (cn)₆The nanospheres are applied to the negative electrode of a lithium electronic battery.

10. The use of iodine doped graphene coated hierarchical pore prussian blue nanospheres according to claim 9, wherein: the working electrode of the lithium ion battery is prepared from the following components in percentage by mass of 80: 10: iodine doped graphene coated hierarchical pores FeFe (CN) of 10₆Nanosphere, acetylene black and polyvinylidene fluoride.

Technical Field

The invention relates to the field of battery application, in particular to hierarchical-pore Prussian-blue nanospheres wrapped by iodine-doped graphene and a preparation method and application thereof.

Background

With the rapid development of intelligent robots and new energy electric vehicles, Lithium Ion Batteries (LIBs) are widely used as main energy storage devices by , and the existing lithium ion batteries mostly adopt graphite as a negative electrode material due to relatively low theoretical capacity (LiC) of the graphite₆Is 372 mAh g^-1) The practical application of the lithium battery is limited, particularly in new energy electric vehicles, so that the development of new -generation lithium battery electrode materials is imminent.

Prussian blue (Fe) as an artificially synthesized polymer of th₄[Fe(CN)₆]₃·14H₂O, Prussianblue, PB for short) has the advantages of excellent electrochemical reversibility, high stability, easiness in preparation and the like, so that the method has a great application prospect in the aspects of chemically modified electrodes, electrochromism, secondary batteries and the like.

However, for the reported application of prussian blue to the negative electrode of the lithium ion battery, the research of the prussian blue generally has the characteristics of poor conductivity, low charge and discharge capacity, unstable cycle and the like. Thus, the prior art is yet to be improved and enhanced.

Disclosure of Invention

The invention aims to provide graded-pore Prussian-blue nanospheres coated on the basis of iodine-doped graphene as well as a preparation method and application thereof, and aims to solve the technical problems of poor conductivity, low charge and discharge capacity and unstable cycle of lithium batteries in the prior art.

The technical scheme of the invention comprises the following steps:

preparation method of hierarchical pore Prussian blue nanospheres wrapped by iodine-doped graphene, which comprises the following steps of A, adding K₃[Fe(CN)₆]Dissolving in deionized water, adding surfactant, ultrasonic stirringAdding inorganic acid solution into the clear solution, stirring, heating to 70-90 ℃ under magnetic stirring, reacting for 22-26h, and cooling to room temperature; centrifuging to collect precipitate, washing with distilled water and ethanol several times, and vacuum drying at 50-70 deg.C for 10-14 h to obtain solid FeFe (CN)₆A nanosphere precursor;

B. solid FeFe (CN) prepared above₆Respectively adding the nanosphere precursor and the surfactant into an inorganic acid solution, uniformly stirring, heating to 120 ℃ in a sealed environment, continuously reacting for 4-6h, and gradually cooling to room temperature to obtain FeFe (CN) with graded pores₆Nanospheres;

C. iodine doped graphene and the prepared FeFe (CN) with graded pores₆Adding the nanosphere into ionized water, performing ultrasonic treatment for 1-2h, and freeze-drying for 46-50h to obtain iodine-doped graphene-coated hierarchical pore FeFe (CN)₆Nanospheres.

The preparation method of the hierarchical pore Prussian blue nanospheres based on iodine-doped graphene coating comprises the step A of preparing the K₃[Fe(CN)₆]And the surfactant in a mass ratio of 1:15 to 1:30, wherein the concentration of the inorganic acid solution is 0.5M.

The preparation method of the graded-pore Prussian blue nanospheres coated on the basis of iodine-doped graphene comprises the step B of solid FeFe (CN)₆The mass ratio of the nanosphere precursor to the surfactant is 1:3-1:5, the concentration of the inorganic acid solution is 1.0-2.0M, the reaction time of temperature rise is 4.5-5h, the temperature rise rate is 2-5 ℃/min, the temperature drop rate is 0.2-2 ℃/min, and the nanosphere precursor and the surfactant have hierarchical pores FeFe (CN)₆The particle size of the nanosphere is 100-200 nm.

The preparation methods of hierarchical pore Prussian blue nanospheres wrapped by iodine-doped graphene comprise the step of preparing the hierarchical pore Prussian blue nanospheres, wherein the surfactant is any of polyvinylpyrrolidone, cetyl trimethyl ammonium bromide or polyvinylidene fluoride.

According to the preparation method of the graded-hole Prussian blue nanospheres wrapped by the iodine-doped graphene, the inorganic acid solution is any of hydrochloric acid, sulfuric acid and nitric acid.

The preparation method of the hierarchical pore Prussian blue nanospheres based on iodine-doped graphene wrapping comprises the step C of adding iodine-doped graphene and FeFe (CN) with hierarchical pores₆The mass ratio of the nanospheres is 1:5-1:10, ultrasonic treatment is carried out for 1.0-1.5h, and freeze drying is carried out for 48-50 h.

The preparation method of the hierarchical pore Prussian blue nanospheres based on iodine-doped graphene wrapping comprises the following steps of A1 and K₃[Fe(CN)₆]Dissolving in deionized water, adding polyvinylpyrrolidone, ultrasonically stirring to obtain clear solution, adding HCl solution, stirring, heating to 80 deg.C under magnetic stirring, reacting for 24 hr, and cooling to room temperature; the precipitate was collected by centrifugation, washed several times with distilled water and ethanol and dried under vacuum at 60 ℃ for 12h to obtain solid FeFe (CN)₆A nanosphere precursor;

b1, solid FeFe (CN) prepared by the above method₆Respectively adding the nanosphere precursor and the surfactant into an inorganic acid solution, uniformly stirring, heating to 120 ℃ in a sealed environment, continuously reacting for 5 hours, and then gradually cooling to room temperature to obtain FeFe (CN) with graded pores₆Nanospheres;

c1, doping iodine with graphene and FeFe (CN) with hierarchical pore prepared by the method₆Adding the nanosphere into ionized water, performing ultrasonic treatment for 1.5h, and freeze-drying for 48h to obtain iodine-doped graphene-coated hierarchical pore FeFe (CN)₆Nanospheres.

hierarchical pore Prussian blue nanospheres based on iodine doped graphene encapsulation prepared by the Nian method described above, wherein the iodine doped graphene encapsulated hierarchical pore FeFe (CN)₆The nanosphere is a dark blue powder structure, and the spherical particle size is 150-200 nm.

applications of the hierarchical pore Prussian blue nanospheres based on iodine doped graphene wrapping as described above, which are applied to the negative electrode of the lithium electronic battery.

According to the application of the iodine-doped graphene-coated hierarchical pore Prussian blue nanospheres, the working electrode of the lithium electronic battery is prepared from the following components in percentage by mass of 80: 10: 10 graded pore based on iodine doped graphene encapsulation FeFe (CN)₆Nanosphere, acetylene black and polyvinylidene fluoride.

The technical scheme of the invention has the following beneficial effects:

1. the invention firstly mixes the iodine doped graphene (IG for short) with a large amount of electrochemical active sites and enhanced conductivity with FeFe (CN) with uniformly graded pores₆The iodine-doped graphene-coated hierarchical pore Prussian blue nanospheres prepared by the method have the advantages of small and uniform size of and high reaction yield, and have the characteristics of strong crystallinity, good stability and the like of reaction products after being etched by inorganic acid solutions (particularly HCl solutions) with different temperatures and proper concentrations.

2. The hierarchical pore Prussian blue nanospheres coated by the iodine-doped graphene, which are obtained by the invention, are used as main cathode materials in lithium ion batteries, wherein FeFe (CN)₆The nanospheres have the characteristic of hierarchical pores, can be mutually communicated and have hierarchical porous structures with pores of different scales, are favorable for improving the electrochemical performance of the cathode, keep good appearance before and after reaction, do not collapse or deform at all, can achieve the electrochemical effect superior to the existing product, and show the characteristics of difficult attenuation of the cathode capacity of the lithium ion battery, good rate capability and the like.

By the preparation method, Prussian blue FeFe (CN) can be effectively added₆The conductivity of the nanospheres can be improved, and Prussian blue FeFe (CN)₆The nanosphere still keeps better performance after being charged and discharged for many times. The lithium ion battery cathode material prepared from the material has the advantages of good capacity, low attenuation tendency and long service life. And the preparation method of the embodiment has simple process and convenient operation, and is suitable for large-scale industrial production.

Drawings

FIG. 1 shows iodine doped graphene, solid FeFe (CN) in the preparation process of examples 1 to 7 of the present invention₆Nanosphere precursor, FeFe (CN) with hierarchical pores₆Nanosphere and iodine doped graphene coated hierarchical pores FeFe (CN)₆Nano meterBall (i.e. FeFe (CN))₆@ IG);

FIG. 2 shows FeFe (CN) having graded pores in the preparation processes of examples 1 to 7 of the present invention₆A nanosphere XRD spectrogram;

FIG. 3 shows FeFe (CN) having graded pores in the preparation processes of examples 1 to 7 of the present invention₆Nanosphere element distribution images;

FIG. 4 shows the iodine doped graphene and the iodine doped graphene coated hierarchical pore FeFe (CN) during the preparation of the embodiments 1 to 7 of the present invention₆X-ray photoelectron spectroscopy of nanospheres;

FIG. 5 shows the iodine doped graphene coated hierarchical pore FeFe (CN) during the preparation of examples 1 to 7 of the present invention₆The nanospheres have electrochemical performance as electrode materials;

FIG. 6 shows the iodine doped graphene coated hierarchical pore FeFe (CN) during the preparation of examples 1 to 7 of the present invention₆A nanosphere circulating CV curve and a first-circle discharging platform;

FIG. 7 shows the iodine doped graphene coated hierarchical pore FeFe (CN) during the preparation of examples 1 to 7 of the present invention₆Nanosphere at 2000mA g^-1Current density of (a);

FIG. 8 shows the iodine doped graphene coated hierarchical pore FeFe (CN) during the preparation of examples 1 to 7 of the present invention₆Nanosphere (FeFe (CN)₆@ IG) as electrode material before and after reaction.

Detailed Description

The specific implementation process of the iodine-doped graphene-coated hierarchical pore prussian blue nanosphere, the preparation method and the application thereof is described below.

The embodiment provides a preparation method of hierarchical pore Prussian blue nanospheres based on iodine-doped graphene wrapping, which comprises the following steps of firstly, adding K₃[Fe(CN)₆]Dissolving in deionized water, adding surfactant, ultrasonic stirring to obtain clear solution, adding inorganic acid solution, stirring, heating, magnetically stirring, heating to 70-90 deg.C, reacting for 22-26 hr, and cooling to room temperature; centrifuging to collect precipitate, washing with distilled water and ethanol for several times, and vacuum drying at 50-70 deg.CDrying for 10-14 h to obtain solid FeFe (CN)₆And (5) a nanosphere precursor. In this step, K is₃[Fe(CN)₆]And a surfactant at a mass ratio of preferably 1:15 to 1:30, and the concentration of the inorganic acid solution is 0.5M, and it is possible to prepare a hierarchical pore FeFe (CN) having a size of only by using the above experimental conditions in the present invention₆The concentration of the inorganic acid solution in the embodiment is relatively high, if the concentration of the inorganic acid (such as hydrochloric acid) is too high, the etched cavity is too large, no action constraint is imposed on the migration of lithium ion of the lithium ion battery, if the concentration of the inorganic acid is too low, the etching is incomplete, and a sample with graded holes cannot be obtained, so that the optimal concentration of the inorganic acid solution in the embodiment is about 0.5M, and the optimal preparation effect is achieved.

Next, the solid FeFe (CN) prepared above was mixed₆Respectively adding the nanosphere precursor and the surfactant into an inorganic acid solution, uniformly stirring, heating to 120 ℃ in a sealed environment, continuously reacting for 4-6h, and gradually cooling to room temperature to obtain FeFe (CN) with graded pores₆Nanospheres. In this step, the solid FeFe (CN)₆The mass ratio of the nanosphere precursor to the surfactant is 1:3-1:5, the concentration of the inorganic acid solution is 1.0-2.0M, the reaction time of temperature rise is 4.5-5h, the temperature rise rate is 2-5 ℃/min, the temperature drop rate is 0.2-2 ℃/min, and the nanosphere precursor and the surfactant have hierarchical pores FeFe (CN)₆The particle size of the nanosphere is 100-200 nm.

Finally, iodine doped graphene and the prepared FeFe (CN) with hierarchical pores₆Adding the nanosphere into ionized water, performing ultrasonic treatment for 1-2h, and freeze-drying for 46-50h to obtain iodine-doped graphene-coated hierarchical pore FeFe (CN)₆Nanospheres. Preferably, in this step, the iodine doped graphene and the FeFe (CN) having hierarchical pores₆The mass ratio of the nanospheres is 1:5-1:10, ultrasonic treatment is carried out for 1.0-1.5h, and freeze drying is carried out for 48-50 h.

In the preferred embodiment, PVP is adopted as the surfactant, which is synthetic water-soluble polymer surfactants, the molecule contains hydrophobic methylene carbon chain and strong polar internal acyl group, and the PVP can be adsorbed on the surface of the nano particle in various ways to ensure that the PVP can be adsorbed on the surface of the nano particle in various waysRemarkably reduced surface tension, and has effect in preventing FeFe (CN)₆The effect of particle agglomeration. In addition, the inorganic acid solution adopted by the invention is hydrochloric acid (HCl) or sulfuric acid (H)₂SO₄) And nitric acid (HNO)₃) Among , hydrochloric acid solution is particularly preferable, and it is advantageous that Cl is dissociated in the solution^-Minimal anion volume, cause FeFe (CN)₆The change of agglomeration on the particle surface is minimal.

The iodine-doped graphene-coated hierarchical pore FeFe (CN) can be prepared by the preparation method₆Nanospheres (i.e. FeFe (CN))₆@ IG) having a spherical particle diameter of 150-. The FeFe (CN) thus prepared₆The @ IG is applied to the negative electrode of the lithium-ion battery, is favorable for improving the electrochemical performance of the negative electrode, keeps good appearance before and after reaction, does not collapse or deform, can achieve the electrochemical effect superior to the existing product, and shows the characteristics that the capacity of the negative electrode of the lithium-ion battery is not easy to attenuate and the rate capability is good.

The technical solution of the present invention is further illustrated by through the following specific examples.