Preparation method and application of MnO2/PPy composite material with three-dimensional mesoporous microsphere structure
阅读说明：本技术 一种三维介孔微球结构MnO2/PPy复合材料的制备方法及其应用 (Preparation method and application of MnO2/PPy composite material with three-dimensional mesoporous microsphere structure ) 是由 尹成杰 廖晓波 潘成岭 于 2021-09-28 设计创作，主要内容包括：本发明公开了一种三维介孔微球结构MnO-(2)/PPy复合材料的制备方法及其应用,先通过化学氧化聚合制备得到PPy纳米线,并以PPy纳米线为模板通过氧化还原反应在PPy纳米线团中穿插合成MnO-(2)纳米棒,得到具有三维介孔微球结构的MnO-(2)/PPy复合材料。这种复合材料用作锌离子电池正极时,表现出优异的电化学性能,具有高达361.8mAh/g的放电比容量。本发明所用原料可再生,环境友好,在水系锌离子电池大规模能量存储方面有良好的应用前景。(The invention discloses MnO with a three-dimensional mesoporous microsphere structure 2 Firstly, PPy nano-wire is prepared by chemical oxidation polymerization, and MnO is synthesized in PPy nano-wire group by redox reaction with PPy nano-wire as template 2 Nano-rods to obtain MnO with a three-dimensional mesoporous microsphere structure 2 a/PPy composite material. When the composite material is used as a positive electrode of a zinc ion battery, excellent electricity is shownChemical property, and has a specific discharge capacity as high as 361.8 mAh/g. The raw materials used in the invention are renewable and environment-friendly, and have good application prospect in the aspect of large-scale energy storage of the water system zinc ion battery.)
1. MnO with three-dimensional mesoporous microsphere structure2The preparation method of the/PPy composite material is characterized by comprising the following steps:
s1: synthesizing a PPy nanowire by using a chemical oxidative polymerization method by using a pyrrole monomer and an ammonium persulfate solution as raw materials and cetyl trimethyl ammonium bromide as a template;
s2: dispersing PPy nano-wires in deionized water, and then adding MnSO4•H2O, obtaining a mixed solution, and forming a PPy nanowire group in the mixed solution by the PPy nanowire;
s3: adding ammonium persulfate solution into the mixed solution under the stirring condition to obtain a mixture, and performing hydrothermal reaction to obtain MnSO4•H2MnO formed by thermal decomposition of O2Interpenetration and synthesis of MnO in PPy nanowire coils2Washing and drying the nano-rods to obtain MnO with a three-dimensional mesoporous microsphere structure2a/PPy composite material.
2. The three-dimensional mesoporous microsphere structure MnO of claim 12The preparation method of the/PPy composite material is characterized by comprising the following steps: in step S1, the molar ratio of pyrrole monomer to ammonium persulfate is 1: 1.2.
3. the preparation method of the three-dimensional mesoporous microsphere structure MnO2/PPy composite material of claim 1, wherein the preparation method comprises the following steps: in step S1, the molar ratio of cetyltrimethylammonium bromide to pyrrole monomer is 1: 4.
4. the three-dimensional mesoporous microsphere structure MnO of claim 12The preparation method of the/PPy composite material is characterized by comprising the following steps: in step S1, the temperature of the chemical oxidative polymerization method is 0-5%oAnd C, the time is 4 hours.
5. The three-dimensional mesoporous microsphere junction according to claim 1Form MnO2The preparation method of the/PPy composite material is characterized by comprising the following steps: in step S2, the amount of PPy nanowires was 0.04g, and the amount of deionized water was 40 ml.
6. The three-dimensional mesoporous microsphere structure MnO of claim 12The preparation method of the/PPy composite material is characterized by comprising the following steps: in step S2, MnSO4•H2The amount of O was 4.6 mmol.
7. The three-dimensional mesoporous microsphere structure MnO of claim 12The preparation method of the/PPy composite material is characterized by comprising the following steps: in step S3, the amount of ammonium persulfate added was 9.2 mmol.
8. The three-dimensional mesoporous microsphere structure MnO of claim 12The preparation method of the/PPy composite material is characterized by comprising the following steps: in step S3, the hydrothermal reaction was carried out at 120 ℃ for 12 hours.
9. A zinc ion battery positive electrode is characterized in that: the material of the positive electrode of the zinc ion battery comprises MnO with a three-dimensional mesoporous microsphere structure prepared by the method of any one of claims 1 to 82a/PPy composite material.
10. A zinc ion battery comprises a zinc ion battery body and is characterized in that: the positive electrode of the zinc-ion battery body is the positive electrode of the zinc-ion battery according to claim 9.
Technical Field
The invention relates to the field of water-based zinc ion batteries, in particular to MnO with a three-dimensional mesoporous microsphere structure2A preparation method and application of a/PPy composite material.
Background
With the excessive consumption of fossil fuels, energy crisis and climate deterioration have become issues to be solved urgently in the world. Currently, a lithium ion battery, as a traditional energy storage device, is widely used in the fields of electrochemical energy storage, electric vehicles, flexible and wearable electronic devices, and the like due to its advantages of high energy density, long service life, and the like. However, due to the poor safety performance of lithium ion batteries and the increasing shortage of lithium resources, the development of new batteries with high specific energy and low cost will become an important research direction in the battery field.
Benefit from Zn2+Low redox potential (-0.76V vs. standard hydrogen electrode), high theoretical specific capacity (820mAh g/Zn-1) And good cycle stability, zinc ion batteries have become increasingly popular for research. Meanwhile, due to the outstanding influence of the anode material on the electrochemical performance of the zinc ion battery, various anode materials, such as manganese-based materials, vanadium-based materials, Prussian blue analogues, carbon materials, polymer materials and the like, are widely researched. Among these positive electrode materials, manganese-based materials are being intensively studied due to their relatively high energy density.
The manganese dioxide material belongs to one of manganese-based anode materials, the unique tunnel structure and the crystal form diversity of the manganese dioxide material can obviously improve the structure designability of the anode material of the zinc ion battery, and meanwhile, the manganese dioxide anode material is low in cost, environment-friendly and high in safety, so that the manganese dioxide anode material has a wide application prospect. However, the manganese dioxide cathode material has poor conductivity and low structural stability, thereby causing adverse effects on the rate capability and long-cycle stability of the zinc ion battery. At present, commercial manganese dioxide particles are large in size, poor in conductivity and low in charging and discharging specific capacity, and the phenomena of nonuniform dispersion and the like easily occur in the process of preparing an electrode by mixing the manganese dioxide particles with a conductive agent, so that the stable high-rate charging and discharging cycle performance is difficult to maintain under high current density. Therefore, the overall performance of the zinc ion battery can be effectively improved by modifying and optimizing the manganese dioxide material.
The method disclosed in chinese document CN110364693A optimizes the electrochemical performance of manganese dioxide material by using porous hollow nano three-dimensional conductive skeleton to be compounded with manganese dioxide. The porous hollow nano three-dimensional conductive framework is obtained by calcining the MOF material at high temperature, and the method not only consumes energy, but also has complex synthetic process and increases the cost of large-scale application. In the method disclosed in chinese document CN112582602A, a mechanical ball milling method is used to compound commercial manganese dioxide with graphite nanoplatelets. The composite material obtained by the ball milling method is unstable in composite state, and a zinc battery prepared by taking the composite material obtained by the invention as a positive electrode material has general electrochemical performance.
Disclosure of Invention
In view of the above, there is a need to provide MnO with a three-dimensional mesoporous microsphere structure having higher specific capacity and cycle stability2A preparation method and application of a/PPy composite material.
In order to solve the technical problems, the technical scheme of the invention is as follows: a preparation method of a three-dimensional mesoporous microsphere structure MnO2/PPy composite material comprises the following steps:
s1: synthesizing a PPy nanowire by using a chemical oxidative polymerization method by using a pyrrole monomer and an ammonium persulfate solution as raw materials and cetyl trimethyl ammonium bromide as a template;
s2: dispersing PPy nano-wires in deionized water, and then adding MnSO4•H2O, obtaining a mixed solution, and forming a PPy nanowire group in the mixed solution by the PPy nanowire;
s3: adding ammonium persulfate solution into the mixed solution under the stirring condition to obtain a mixture, and performing hydrothermal reaction to obtain MnSO4•H2MnO formed by thermal decomposition of O2Interpenetration and synthesis of MnO in PPy nanowire coils2Washing and drying the nano-rods to obtain MnO with a three-dimensional mesoporous microsphere structure2a/PPy composite material.
Further, in step S1, the molar ratio of pyrrole monomer to ammonium persulfate is 1: 1.2.
further, in step S1, the molar ratio of cetyltrimethylammonium bromide to pyrrole monomer is 1: 4.
further, in step S1, the temperature of the chemical oxidative polymerization method is 0-5 deg.CoC，The time period required was 4 hours.
Further, in step S2, the amount of PPy nanowire was 0.04g, and the amount of deionized water was 40 ml.
Further, in step S2, MnSO4•H2The amount of O was 4.6 mmol.
Further, in step S3, the amount of ammonium persulfate added was 9.2 mmol.
Further, in step S3, the hydrothermal reaction was carried out at 120 ℃ for 12 hours.
In order to solve the technical problems, the second technical scheme of the invention is as follows: the zinc ion battery anode is made of MnO with the three-dimensional mesoporous microsphere structure prepared by the method2a/PPy composite material.
In order to solve the technical problems, the third technical scheme of the invention is as follows: a zinc ion battery comprises a zinc ion battery body, wherein the positive electrode of the zinc ion battery body is the positive electrode of the zinc ion battery.
Compared with the prior art, the invention has the following beneficial effects:
1. MnO with three-dimensional mesoporous microsphere structure2The source of the raw materials of the/PPy composite material is wide, the synthesis method is simple and easy to operate, and the electrochemical performance of the manganese dioxide material can be obviously improved.
2. MnO with three-dimensional mesoporous microsphere structure2the/PPy composite material has a unique three-dimensional mesoporous microsphere structure, and is beneficial to the insertion/extraction of zinc ions in the charge and discharge process of a zinc ion battery.
3. MnO with three-dimensional mesoporous microsphere structure2PPy nanowires in/PPy composites are effective for MnO reduction2The nanorods are connected in series, so that the conductivity of the material is greatly improved.
4. The method is simple, convenient, easy to operate and recyclable, and the MnO with the three-dimensional mesoporous microsphere structure prepared by the method is utilized2The zinc ion battery using the/PPy composite material as the positive electrode material has high charge and discharge stability, low cost of raw materials, suitability for industrial production and wide application prospect in the aspect of zinc ion positive electrode materials.
In order to make the aforementioned and other objects, features and advantages of the invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
FIG. 1 shows MnO with a three-dimensional mesoporous microsphere structure prepared in the first embodiment of the present invention2XRD pictures in the/PPy composite.
FIG. 2 shows MnO with a three-dimensional mesoporous microsphere structure prepared in the first embodiment of the present invention2And (3) low-magnification scanning electron microscope pictures in the/PPy composite material.
FIG. 3 shows MnO with a three-dimensional mesoporous microsphere structure prepared according to the first embodiment of the present invention2High magnification scanning electron microscope picture in the/PPy composite material.
FIG. 4 is pure MnO2MnO with three-dimensional mesoporous microsphere structure prepared in the first embodiment of the invention2The multiplying power performance of the/PPy composite material is compared with that of the other composite material.
FIG. 5 is pure MnO2MnO with three-dimensional mesoporous microsphere structure prepared in the first embodiment of the invention2And the charge and discharge performance of the 50 th circle and the 100 th circle in the long-cycle test of the/PPy composite material are compared.
Detailed Description
To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments, structures, features and effects according to the present invention will be made with reference to the accompanying drawings and preferred embodiments.
Example one
MnO with three-dimensional mesoporous microsphere structure2The preparation method of the/PPy composite material comprises the following steps:
s1: cetyl trimethyl ammonium bromide and pyrrole monomers are mixed in a molar ratio of 1:4 in 200ml of deionized water to form a first solution, and 44ml of 0.2mol/L ammonium persulfate solution is dropwise added into the first solution under magnetic stirring. Stirring for 4 hr, washing with deionized water and ethanol for three times, and washing at 60 deg.CoAnd (3) drying for 12 hours in vacuum at the temperature of C to obtain the PPy nanowire.
S2: 0.04g of the dried PPy nano-wire is weighed and dispersed in 40ml of deionized water, and the mixture is stirred by magnetic forceAdding 4.6mmol of MnSO into the dispersion liquid4•H2And O and 9.2mmol of ammonium persulfate to obtain a mixed solution, wherein the PPy nanowire forms a PPy nanowire group in the mixed solution.
S3: the mixed solution is stirred for 30min and transferred into a 50ml autoclave at 120 DEG CoHydrothermal treatment at C temperature for 12 hours, MnSO4•H2MnO formed by thermal decomposition of O2Interpenetration and synthesis of MnO in PPy nanowire coils2And (4) nanorods. Finally washing with deionized water and ethanol for three times, and washing at 60 deg.CoVacuum drying for 24 hours at the temperature of C to obtain MnO with a three-dimensional mesoporous microsphere structure2the/PPy composite material is ground and weighed, and then the mass product is filled into a weighing bottle for standby.
The XRD pattern of the composite material is shown in figure 1. The material has XRD diffraction peak and standard beta-MnO2The XRD patterns of the PPy nano-wire are corresponding, and the XRD diffraction peak of the PPy nano-wire is displayed at the same time. And compared with standard beta-MnO2The XRD pattern of the composite material has small shift of each XRD diffraction peak, which proves that MnO2Successful synthesis of the/PPy composite, and MnO2And PPy is not simply physical adsorption. The MnO2The scanning electron microscope pictures of the low power and the high power of the/PPy composite material are shown in the figure 2 and the figure 3. Can prove the present MnO2the/PPy composite material has a three-dimensional mesoporous microsphere structure and is composed of PPy nanowires and MnO2And (4) nano rods.
MnO with three-dimensional mesoporous microsphere structure prepared in example one2the/PPy composite material is used as a zinc ion battery anode material, and the rate capability and the charge-discharge cycle performance of the composite material are tested.
Example two
MnO with three-dimensional mesoporous microsphere structure prepared by using method2Zinc ion battery anode made of/PPy composite material
0.04g of conductive carbon black is added into 1g of N-methylpyrrolidone solution of polyvinylidene fluoride with the concentration of 2wt% at normal temperature and normal pressure to obtain a mixed solution. After stirring for 20min, 0.14g of MnO with the three-dimensional mesoporous microsphere structure prepared in the first embodiment is added into the mixed solution2And stirring the/PPy composite material for 4 hours to obtain uniformly mixed anode slurry. The stirring is finishedAnd then uniformly coating the obtained slurry on the surface of the titanium foil. And drying the coated titanium foil, and cutting into small wafers with the diameter of 14mm, namely the zinc ion battery anode.
Zinc ion battery manufactured by using zinc ion battery anode manufactured by using method
The zinc foil is cut into small 14mm pieces as the negative electrode material of the battery, 16mm glass filter paper is used as the positive and negative electrode separation membrane, and the mixed solution of 2M zinc sulfate and 0.1M manganese sulfate is used as the electrolyte to assemble the zinc ion battery.
Testing the rate capability of the prepared zinc ion battery
And (3) testing the rate capability of the prepared zinc ion battery at room temperature by using a newware battery testing system. The prepared zinc ion battery is clamped on a neware battery tester, and the current density of the first three circles of charge-discharge circulation is set to be 0.05A/g, so that the zinc ion battery is used as the activation process of the battery anode material. And then setting the current density to be 0.1, 0.2, 0.5, 1, 1.5, 2 and 3A/g in sequence, wherein the number of charging and discharging cycles is 20 circles under each current density, and finally resetting the current density to be 0.1A/g for 100 circles to obtain the rate performance map of the prepared zinc ion battery.
As shown in FIG. 4, the results show that MnO in the three-dimensional mesoporous microsphere structure prepared by the method of the invention2the/PPy composite material as a zinc battery positive electrode material has more excellent rate performance compared with commercial electrolytic manganese dioxide. And when the final current density returns to 0.1A/g, the zinc battery prepared by the material of the invention shows higher discharge specific capacity than the initial specific capacity. This is largely due to its particular morphology and the good conductivity of PPy nanowires.
And testing the charge-discharge long-cycle performance of the prepared zinc ion battery.
And (3) testing the long-cycle performance of the prepared zinc ion battery at room temperature by using a newware battery testing system. The obtained zinc ion battery is clamped on a neware battery tester, and the current density of the first three circles of charge-discharge circulation is set to be 0.05A/g, so that the zinc ion battery is used as the activation process of the battery anode material. And then setting the current density to be 0.2A/g, and circulating for 1000 circles to obtain a charge-discharge long cycle performance map of the prepared zinc ion battery.
As shown in FIG. 5, the results show that MnO in the three-dimensional mesoporous microsphere structure prepared by the method of the present invention2Compared with commercial electrolytic manganese dioxide, the specific capacity of the zinc battery anode material made of the/PPy composite material is higher at the 50 th circle, and the specific capacity of the zinc battery assembled by commercial manganese dioxide serving as the anode material is reduced to 85.3mAh/g along with the charging and discharging, while the specific capacity of the zinc battery made of the composite material serving as the anode material is increased to 361.8 mAh/g. This phenomenon indicates that the MnO of the present invention has a three-dimensional mesoporous microsphere structure2the/PPy composite material has higher cycle stability and conductivity.
The pseudocapacitance property of the prepared zinc ion battery is tested.
The pseudocapacitance properties of the prepared zinc ion battery were tested at room temperature using the CHI660 electrochemical workstation. The obtained zinc ion battery is clamped into a CHI660 electrochemical workstation, and the CV curve of the zinc ion battery is measured by using cyclic voltammetry at different scanning rates and with a voltage window ranging from 1.8V to 0.8V. And simulating the occupation ratio of the pseudocapacitance in the total capacity of the zinc ion battery according to the obtained CV curve. The different scan rates were 0.4, 0.6, 0.8, 1.0mV/s, respectively.
The results show that the contribution ratios of the pseudocapacitance characteristics in the total specific capacity of the zinc ion battery are 46%, 52.6%, 55.6% and 61.4% in sequence at different scan rates (0.4, 0.6, 0.8, 1.0 mV/s). Proves that the invention has a three-dimensional mesoporous microsphere structure MnO2The zinc ion battery with the/PPy composite material as the anode material has good pseudo-capacitance characteristics.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.