CN105470481A - Nitrogen-doped carbon-coated manganese monoxide composite material with one-dimensional porous core-shell structure and preparation method of nitrogen-doped carbon-coated manganese monoxide composite material - Google Patents

Abstract

The invention relates to a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material and a preparation method thereof. The composite material is doped with nitrogen and has a one-dimensional porous carbon-coated manganese monoxide core-shell structure, the manganese monoxide has a nano-rod structure, and the outer layer of the manganese monoxide nano-rod is covered with an amorphous carbon layer. The invention adopts the in-situ polymer coating method supplemented by calcination to obtain the nitrogen-doped carbon-coated manganese monoxide porous composite material. The preparation method of the composite material is simple, novel and highly adjustable; at the same time, the nitrogen-doped carbon can also store lithium ion, this ingenious design makes the specific capacity of the composite material exceed the theoretical specific capacity of manganese monoxide; in addition, the composite material solves the problems of low capacity and fast decay caused by pure manganese monoxide material with poor conductivity and large volume strain , so that the composite material has excellent electrochemical performance, cycle life and structural stability.

Description

One-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material and preparation method

technical field

The invention belongs to new energy nanometer energy storage materials, and specifically relates to a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material, a preparation method and an application thereof.

Background technique

The widespread use of energy storage devices such as portable electronic devices, electric vehicles, and grid energy storage systems has greatly promoted the rapid development of lithium-ion batteries, which are outstanding representatives of new energy storage. As a negative electrode material for traditional commercial lithium-ion batteries, graphite has greatly limited the further development of lithium-ion batteries due to its low theoretical capacity (372mAh/g) and low cycle life. Therefore, the development of a lithium-ion battery anode material with high specific capacity and excellent cycle performance is of great significance for expanding the application field of lithium-ion batteries.

Compared with other common transition metal oxide anode materials, manganese monoxide has a relatively low charging potential platform (~1.2V, vs. Li/Li ⁺ ), which can improve the working voltage and energy density of the full battery, and its The source is abundant, the price is low, and it is green and environmentally friendly. In particular, manganese monoxide has a high theoretical specific capacity (756mAh/g) and good safety. It is considered to be a negative electrode material with great potential and has been extensively studied. However, in practical applications, there are mainly two problems: on the one hand, the low electronic conductivity of manganese monoxide leads to poor rate performance and low reversible capacity; on the other hand, the volume strain of manganese monoxide is large during the electrochemical cycle. , thus causing material agglomeration and pulverization, and the capacity decays rapidly. These defects have seriously hindered the popularization and application of manganese monoxide in lithium-ion battery anode materials.

In recent years, researchers at home and abroad have mainly prepared porous or carbon-composite manganese monoxide electrode materials to effectively improve their electrochemical performance. For example, Guo et al. of Shandong University (GuoS, LuG, QiuS, et al. Carbon-coatedMnOmicroparticleporous nanocompositesservingasanodematerialswithinhancedelectrochemicalperformances[J]. NanoEnergy, 2014, 9: 41-49.) prepared carbon-coated manganese monoxide porous microsphere composites by hydrothermal method, Compared with the pure sample, the obtained composite material has excellent performance. At 100mA/g, the first-cycle capacity is 590.6mAh/g. After 100 cycles, the capacity is still 525.4mAh/g. When the current density is 800mA/g, the capacity can reach 238.2mAh/g; Sun Yat-sen University Liu et al. (LiuH, LiZ, LiangY, et al. Facile synthesis of MnOmulti-corenitrogen-doped carbonshell nanoparticles for high performancelithium-ionbatteryanodes[J]. Carbon, 2015,84:419-425.) Prepared a carbon-coated multi-core structure The electrochemical performance of the manganese monoxide nanosphere composite material has been significantly improved. At 100mA/g, the capacity of the first cycle is 799mAh/g, which drops to 608mAh/g after 5 cycles, and the capacity is still 578mAh/g after 60 cycles. , at 1000mA/g, the capacity can reach 254mAh/g; although some progress has been made in the research on the modification of manganese monoxide electrode materials, at present, most of the documents and patents including the above-mentioned documents prepare manganese monoxide composite materials. All are relatively complicated and costly. At the same time, at a high current density (greater than 500mA/g), the cycle life is still difficult to exceed 500 cycles or higher, and the specific capacity is still relatively low.

Contents of the invention

The technical problem to be solved by the present invention is to provide a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material, which has a novel structure and combines the characteristics of porous, one-dimensional, nitrogen-doped, and large specific surface area , which greatly suppresses the problem of rapid capacity decay caused by powdering and agglomeration caused by material volume expansion during charge and discharge. At the same time, nitrogen-doped carbon can also store lithium ions, which improves the reversible specific capacity of the composite material. It has good structural stability and excellent cycle performance; moreover, the preparation method is relatively simple and novel, and the cost is low. The prepared material has good structural stability and excellent cycle performance, and is suitable for industrial production. It has great potential in the field of energy storage materials. Huge application potential.

In order to realize the above-mentioned purpose of the invention, the present invention adopts following technical scheme:

A one-dimensional porous core-shell nitrogen-doped carbon-coated manganese monoxide composite material, which is doped with nitrogen, is a one-dimensional porous carbon-coated manganese monoxide core-shell structure, and the manganese monoxide has a nanorod-like structure. The outer layer of the manganese oxide nanorods is coated with an amorphous carbon layer. Provided is a method for preparing a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material, comprising the following steps:

1) adding manganese dioxide nanorods into the oxidizing agent solution, ultrasonically treating them to disperse them, and stirring them magnetically at 0-10°C to make the manganese dioxide nanorods evenly dispersed;

2) adding the aniline monomer into the acid solution, stirring at 0-10°C, so that the aniline is evenly dispersed in the acid solution, and aniline suspension is obtained;

3) The solution of step 1) is quickly added to the suspension of step 2), and after standing at 0-10° C. for 0.5-36 hours, post-treatment is obtained to obtain a polyaniline polymer-coated manganese dioxide composite;

4) The compound obtained in step 3) is subjected to high-temperature heat treatment in a reducing or inert atmosphere, and cooled naturally to obtain a one-dimensional porous core-shell nitrogen-doped carbon-coated manganese monoxide nanocomposite material.

According to the above scheme, the ultrasonic treatment time in the step 1) is 5-30 minutes, and the stirring time is 10-60 minutes.

According to the above scheme, the post-treatment in step 3) is centrifuged washing with water for 3 times, and drying at 60-120°C.

According to the above scheme, the ratio of the amount of manganese dioxide nanorods to the volume of aniline is: 0.3-50mmol:30-250 μL, and the ratio of the amount of aniline to the oxidizing agent is in the range of 1:1-1:4.

According to the scheme, the oxidizing agent is any one of ferric chloride, hydrogen peroxide, potassium iodate, potassium dichromate, ammonium persulfate and cesium sulfate.

According to the above scheme, the acid is inorganic hydrochloric acid, sulfuric acid, perchloric acid and nitric acid, organic acid dodecylsulfonic acid, phytic acid, oxalic acid, citric acid, dodecylbenzenesulfonic acid, camphorsulfonic acid As well as any one of naphthalenesulfonic acid, the ratio of the volume of aniline to the amount of the acid substance is 30-250 μL: 1-5 mmol.

According to the above scheme, the reducing atmosphere is a mixed gas containing 5% hydrogen by volume percentage and the balance being nitrogen, and the inert atmosphere is nitrogen and argon.

According to the above scheme, the high-temperature heat treatment is to raise the temperature to a target temperature of 500-800° C. for 2-10 hours at a heating rate of 1-10° C./min.

The method is supplemented by in-situ polymer coating method and calcination, and the one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material prepared has a high theoretical specific capacity and comparative The characteristics of the low charging potential platform, and the use of nitrogen-doped carbon can greatly improve the conductivity of the material and provide additional storage capacity; in addition, the carbon layer in the one-dimensional porous core-shell coating structure can overcome the manganese monoxide nanorods. During the charging and discharging process, due to the problem of rapid capacity decay due to structural damage, pulverization, and agglomeration caused by volume expansion, the present invention can obtain a one-dimensional porous core-shell structure nitrogen doped with high capacity and excellent cycle stability. The invention discloses a preparation method of heterocarbon-coated manganese monoxide composite electrode material.

Compared with prior art, the beneficial effect of the present invention is:

1) The present invention effectively combines porous properties, one-dimensional manganese monoxide nanorods, and conductive nitrogen-doped carbon to provide a composite material, which can improve the conductivity and specific surface area of the composite material, so that the electrolyte and the composite material can be effectively contact, which can effectively improve the rate performance and specific capacity; the porous structure and conductive nitrogen-doped carbon introduced at the same time can effectively suppress the rapid capacity fading caused by the drastic volume change, so that the prepared composite material has excellent structural stability and cycle life. The introduced nitrogen-doped carbon also has the function of storing lithium ions, making the specific capacity of the composite material higher than the theoretical capacity of manganese monoxide.

2) The present invention utilizes polyaniline in-situ polymerization coating method, first adds oxidizing agent in the solution containing manganese dioxide, then adds aniline monomer, makes the acid solution containing aniline and the mixed solution containing manganese dioxide nanorod rapidly Mixing and reacting under static conditions for polymerization can inhibit manganese dioxide from participating in the reaction during the in-situ synthesis of polyaniline-coated manganese dioxide nanorods, ensuring that polyaniline can be evenly coated on manganese dioxide nanorods , and furthermore, the obtained polyaniline can also be used as a reducing agent and a carbon source, and a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material can be obtained by high-temperature heat treatment. This method is simple, the raw material is easy to adjust, and the cost is low. Low cost, easy to realize industrialization;

Description of drawings

Fig. 1 is the XRD photo of embodiment 1 gained product;

Fig. 2 is the TEM photograph of the product obtained in embodiment 1 (the accompanying drawing in the upper left corner is a HRTEM figure);

Fig. 3 is the XPS photo of embodiment 1 gained product;

Fig. 4 is the cycle performance photo of the simulated battery prepared by the product obtained in Example 1 at 1000mA/g;

Fig. 5 is the cycle performance photo of the simulated battery prepared by the product obtained in Example 1 at 4000mA/g;

Fig. 6 is the rate performance photo of the simulated battery prepared by the product obtained in Example 1;

detailed description

The technical solutions of the present invention will be further described below with specific implementation examples, but the protection scope of the present invention is not limited thereto.

Example 1

1) Weigh 0.52g of manganese dioxide (MnO ₂ ) nanorods prepared by hydrothermal method and 0.46g of ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) into 30mL of deionized water, and use an ultrasonic cleaner to sonicate After 30 minutes of treatment, stir in an ice bath for 15 minutes; manganese dioxide nanorods can be prepared by the following hydrothermal method: Weigh 1.35g of manganese sulfate monohydrate (MnSO ₄ ·H ₂ O) and 1.83g of ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) was dissolved in 70mL of water, stirred for 30 minutes, transferred to a 100mL polytetrafluoroethylene reactor, hydrothermally reacted at 140°C for 12 hours, centrifuged and washed with clean water for 3 times, dried and ready for use.

2) Add 90 μL of aniline monomer (the molar ratio of aniline to ammonium persulfate is 1:2), 0.15 g of oxalic acid (H ₂ C ₂ O ₄ ) into 24 mL of deionized water, and stir in an ice bath for 15 minutes;

3) After the mixed solution prepared in step 1) stops stirring, quickly add the solution of step 2) into the solution of step (1), move it into the freezer at 0-10°C and let it stand for 12 hours. Dried to obtain polyaniline-coated manganese dioxide nanorods with a core-shell structure;

4) Place the polyaniline-coated manganese dioxide nanorods in a tube furnace filled with nitrogen, heat at 650 °C for 10 hours at a heating rate of 10 °C/min, and wait for the tube furnace to cool naturally to obtain a black powder. It is a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material. Fig. 1 is the X-ray diffraction (XRD) pattern of this material, compared with the standard card, the resulting product is manganese monoxide, and the carbon material fails to show diffraction peaks due to amorphization, and there are no other impurities; Fig. 2 is the product The transmission electron microscope (TEM) photo can be found to be an obvious one-dimensional porous core-shell structure, the length of the nanorod is about 1 μm, and the diameter is 100-150 nm. It can be seen from the upper left corner of Figure 2 that the coated carbon is amorphous carbon. The thickness of the carbon layer is about 10nm; Fig. 3 is the X-ray photoelectron spectrum (XPS) of the composite, it can be found that it contains Mn, O, N, C, and the N and C elements should be nitrogen-doped carbon obtained after polyaniline is calcined. Consistent with the composition of the composite nitrogen-doped carbon-coated manganese monoxide.

The one-dimensional porous core-shell structure nitrogen-doped carbon coated manganese monoxide composite material obtained in Example 1 is used to make an electrode as follows:

Weigh one-dimensional porous nitrogen-doped carbon-coated manganese monoxide composite material with a mass ratio of 7:2:1: acetylene black: polytetrafluoroethylene (PVDF), after grinding, add a specific volume of N-methylpyrrolidone (NMP) ultrasonic treatment for 1 hour, evenly coated on the copper foil to make an electrode, using a metal lithium sheet as the positive electrode, the electrolyte is 1mol/LLiPF ₆ /EC-DMC (volume ratio is 1:1), polypropylene microporous The separator was a separator (Celgard 2300), assembled into a half cell. Figure 4 is the long-term cycle curve of the battery assembled from the composite material in the voltage range of 0.01 to 3.0V at a current density of 1000mA/g. It can be found that the composite electrode material has very good cycle stability. Under the current density, the charging capacity of the first cycle is 641.9mAh/g, after 50 cycles, the capacity tends to be stable, and the reversible capacity is 536.2mAh/g; Figure 5 shows the battery assembled by the composite material under the current density of 4000mA/g The cycle performance graph shows that the charging capacity of the first cycle is 246.6mAh/g. After 50 cycles, the capacity gradually increases to 301mAh/g. After 2100 cycles, the capacity is still 266.7mAh/g. Compared with the previous few cycles, the capacity is almost No attenuation, even compared with the highest capacity in the cycling process, the capacity retention rate is 88.6%. It can be seen from Figure 6 that the composite electrode material has good rate performance, and the capacity is at a current density of 50mA/g. The capacity is about 895.6mAh/g, and then the capacity gradually decreases. After 5 cycles, the charging capacity is 819.2mAh/g. Even after high current density charge and discharge, when it returns to low current density (50mA/g), its charge specific capacity It can be basically recovered, and the capacity is about 795mAh/g.

Example 2

1) Weigh 0.26g of manganese dioxide (MnO ₂ ) nanorods prepared by hydrothermal method and 0.46g of ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) into 30mL of deionized water, and use an ultrasonic cleaner to sonicate After 5 minutes of treatment, stir in an ice bath for 10 minutes;

2) Add 180 μL of aniline monomer (the molar ratio of aniline to ammonium persulfate is 1:1), 1.2 g of phytic acid (C ₆ H ₁₈ O ₂₄ P ₆ ) into 24 mL of deionized water, and stir in an ice bath for 10 minutes;

3) After the mixed solution prepared in step 1) stops stirring, quickly add the solution of step 2) into it, move it into the freezer at 0-10°C and let it stand for 0.5 hours, after washing with water for 3 times, dry it at 60°C to obtain the core-shell structure Manganese dioxide nanorods coated with polyaniline;

4) Place the polyaniline-coated manganese dioxide nanorods in a tube furnace filled with argon, heat at 500 °C for 2 hours at a heating rate of 1 °C/min, and wait for the tube furnace to cool naturally to obtain a black powder , which is a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material.

Example 3

1) Weigh 0.52 g of manganese dioxide (MnO ₂ ) nanorods prepared by hydrothermal method, 80 μL of hydrogen peroxide ((H ₂ O ₂ ) into 30 mL of deionized water, and use an ultrasonic cleaner to sonicate for 30 minutes, Stir in ice bath for 15 minutes;

2) Add 60 μL of aniline monomer (the molar ratio of aniline to hydrogen peroxide is 1:4), 0.15 g of oxalic acid (H ₂ C ₂ O ₄ ) into 24 mL of deionized water, and stir in an ice bath for 15 minutes;

3) After the mixed solution prepared in step 1) stops stirring, quickly add the solution of step 2) into it, move it into the freezer at 0-10°C and let it stand for 6 hours, and after washing with water for 3 times, dry it at 90°C to obtain the core-shell structure Manganese dioxide nanorods coated with polyaniline;

4) Place polyaniline-coated manganese dioxide nanorods in a tube furnace filled with nitrogen, heat at 800 °C for 2 hours at a heating rate of 5 °C/min, and wait for the tube furnace to cool naturally to obtain a black powder. It is a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material.

Example 4

1) Weigh 4.30g of manganese dioxide (MnO ₂ ) nanorods and 0.33g of ferric chloride (FeCl ₃ ) prepared by the hydrothermal method and add them into 30mL of deionized water. Stir for 60 minutes;

2) Add 180 μL of aniline monomer (the molar ratio of aniline to ferric chloride is 1:1), 0.3 g of oxalic acid (H ₂ C ₂ O ₄ ) into 24 mL of deionized water, and stir in an ice bath for 60 minutes;

3) After the mixed solution prepared in step 1) stops stirring, quickly add the solution of step 2) into it, move it into the freezer at 0-10°C and let it stand for 36 hours, after washing with water for 3 times, dry it at 120°C to obtain the core-shell structure Manganese dioxide nanorods coated with polyaniline

4) The polyaniline-coated manganese dioxide nanorods were placed in a tube furnace filled with a reducing gas (nitrogen:hydrogen volume ratio of 95:5), and kept at 800°C for 10 hours at a heating rate of 10°C/min. Hours, after the tube furnace was cooled naturally, black powder was obtained, which was a one-dimensional porous core-shell nitrogen-doped carbon-coated manganese monoxide composite material.

Example 5

1) Weigh 0.26g of manganese dioxide (MnO ₂ ) nanorods prepared by hydrothermal method, 0.86g of potassium iodate (KIO ₃ ) into 30mL of deionized water, ultrasonically treat for 30 minutes with an ultrasonic cleaner, and place in an ice bath Stir for 15 minutes;

2) Add 90 μL of aniline monomer (the molar ratio of aniline to potassium iodate is 1:2), 0.96 g of citric acid (C ₆ H ₈ O ₇ ) into 24 mL of deionized water, and stir in an ice bath for 15 minutes;

3) After the mixture prepared in step 1) stops stirring, quickly add the solution of step 2) into it, move it into the freezer at 0-10°C and let it stand for 30 hours, after washing with water for 3 times, dry it at 90°C to obtain the core-shell structure Manganese dioxide nanorods coated with polyaniline

4) The polyaniline-coated manganese dioxide nanorods were placed in a tube furnace filled with a reducing gas (nitrogen:hydrogen volume ratio of 95:5), and kept at 500°C for 10 hours at a heating rate of 1°C/min. Hours, after the tube furnace was cooled naturally, black powder was obtained, which was a one-dimensional porous core-shell nitrogen-doped carbon-coated manganese monoxide composite material.

Example 6

1) Weigh 1.04g of manganese dioxide (MnO ₂ ) nanorods and 1.76g of potassium dichromate (K ₂ Gr ₂ O ₇ ) prepared by the hydrothermal method and add them into 60mL of deionized water, and ultrasonically treat them with an ultrasonic cleaner for 30 Minutes later, stir in an ice bath for 15 minutes;

2) Add 180 μL of aniline monomer (the molar ratio of aniline to potassium dichromate is 1:2), 1.2 g of oxalic acid (H ₂ C ₂ O ₄ ) into 48 mL of deionized water, and stir in an ice bath for 15 minutes;

3) After the mixture prepared in step 1) stops stirring, quickly add the solution of step 2) into it, move it into a freezer at 0-10°C and let it stand for 24 hours, wash it with water for 3 times, and dry it at 120°C to obtain a core-shell structure Manganese dioxide nanorods coated with polyaniline

4) Place polyaniline-coated manganese dioxide nanorods in a tube furnace filled with nitrogen, heat at 650 °C for 5 hours at a heating rate of 10 °C/min, and wait for the tube furnace to cool naturally to obtain a black powder. It is a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material.

Example 7

1) Weigh 1.04g of manganese dioxide (MnO ₂ ) nanorods prepared by hydrothermal method and 1.09g of cesium sulfate (Cs ₂ SO4) into 60mL of deionized water, and use an ultrasonic cleaner to sonicate for 30 minutes. Stir for 15 minutes;

2) Add 180 μL of aniline monomer (the molar ratio of aniline to cesium sulfate is 1:1.5), 1 mL of hydrochloric acid (HCl; 38% mass fraction concentrated acid) into 48 mL of deionized water, and stir in an ice bath for 15 minutes;

3) After the mixed solution prepared in step 1) stops stirring, quickly add the solution of step 2) into it, move it into the freezer at 0-10°C and let it stand for 36 hours, after washing with water for 3 times, dry it at 100°C to obtain the core-shell structure Manganese dioxide nanorods coated with polyaniline

4) Place polyaniline-coated manganese dioxide nanorods in a tube furnace filled with nitrogen, heat at 700 °C for 5 hours at a heating rate of 5 °C/min, and wait for the tube furnace to cool naturally to obtain a black powder. It is a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material.

Example 8

1) Weigh 0.44g of manganese dioxide (MnO ₂ ) nanorods prepared by the hydrothermal method, 1.81g of cesium sulfate (Cs2SO4) into 30mL of deionized water, ultrasonically treat with an ultrasonic cleaner for 30 minutes, and stir in an ice bath for 15 minutes. minute;

2) Add 180 μL of aniline monomer (the molar ratio of aniline to cesium sulfate is 1:2.5), 1.2 g of phytic acid (C ₆ H ₁₈ O ₂₄ P ₆ ) into 24 mL of deionized water, and stir in an ice bath for 15 minutes;

3) After the mixture prepared in step 1) stops stirring, quickly add the solution of step 2) into it, move it into the freezer at 0-10°C and let it stand for 12 hours, wash it with water for 3 times, and dry it at 90°C to obtain a core-shell structure Manganese dioxide nanorods coated with polyaniline

4) Place the polyaniline-coated manganese dioxide nanorods in a tube furnace filled with argon, heat at 650 °C for 5 hours at a heating rate of 10 °C/min, and wait for the tube furnace to cool naturally to obtain a black powder , which is a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material.

Example 9

1) Weigh 4.30g of manganese dioxide (MnO ₂ ) nanorods and 6.38g of ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) into 300mL of deionized water, ultrasonically treat for 30 minutes with an ultrasonic cleaner, and place on ice Bath stirring for 15 minutes;

2) Add 250 μL of aniline monomer (the molar ratio of aniline to ammonium persulfate is 1:1), 1.5 g of oxalic acid (C ₆ H ₁₈ O ₂₄ P ₆ ) into 240 mL of deionized water, and stir in an ice bath for 15 minutes;

3) After the mixed solution prepared in step 1) stops stirring, quickly add the solution of step 2) into it, move it into the freezer at 0-10°C and let it stand for 12 hours, after washing with water for 3 times, dry it at 120°C to obtain a core-shell structure Manganese dioxide nanorods coated with polyaniline

4) Place the polyaniline-coated manganese dioxide nanorods in a tube furnace filled with argon, heat at 700 °C for 8 hours at a heating rate of 10 °C/min, and wait for the tube furnace to cool naturally to obtain a black powder , which is a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material.

Example 10

1) Weigh 0.52g of manganese dioxide (MnO ₂ ) nanorods prepared by the hydrothermal method and 90 μL of hydrogen peroxide (H ₂ O ₂ ) into 30 mL of deionized water, and use an ultrasonic cleaner to sonicate for 30 minutes. Bath stirring for 15 minutes;

2) Add 90 μL of aniline monomer (the molar ratio of aniline to hydrogen peroxide is 1:3), 1 mL of concentrated sulfuric acid (H ₂ SO ₄ ; 98% mass fraction of concentrated acid) into 24 mL of deionized water, and stir in an ice bath for 15 minutes;

3) After the mixed solution prepared in step 1) stops stirring, quickly add the solution in step 2) to it, move it into the freezer and let it stand for 12 hours, wash it with water for 3 times, and dry it at 90°C to obtain polyaniline coating with core-shell structure Manganese dioxide nanorods

4) Place the polyaniline-coated manganese dioxide nanorods in a tube furnace filled with argon, heat at 550 °C for 10 hours at a heating rate of 2 °C/min, and wait for the tube furnace to cool naturally to obtain a black powder , which is a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material.

The one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material of Examples 2-10 was prepared as an electrode by the method of Reference Example 1, and the battery performance test was carried out. The results are shown in Table 1.

Table 1

Claims (10)

1. the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon, it is characterized in that: doped with nitrogen in this composite material, for the coated manganese monoxide nucleocapsid structure of one dimension porous carbon, manganese monoxide is nano bar-shape structure, and the external sheath of manganese monoxide nanometer rods has amorphous carbon layer.

2. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 1, is characterized in that: comprise the steps:

1) add in oxidizing agent solution by manganese dioxide nano-rod, ultrasonic process makes it disperse, and under 0 ~ 10 DEG C of condition, magnetic agitation, makes manganese dioxide nano-rod be uniformly dispersed;

2) aniline monomer is added in acid solution, stir under 0 ~ 10 DEG C of condition, make aniline be dispersed in acid solution, obtain aniline suspension;

3) by step 1) solution adds step 2 rapidly) suspension, 0 ~ 10 DEG C leaves standstill reprocessing in 0.5 ~ 36 hour, obtains the compound of the coated manganese dioxide of polyaniline polymer;

4) by step 3) gained compound carries out high-temperature heat treatment under reproducibility or inert atmosphere, and naturally cool, obtain the coated manganese monoxide nano composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon.

3. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 2, is characterized in that: described step 1) in sonication treatment time be 5 ~ 30 minutes, mixing time is 10 ~ 60 minutes.

4. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 2, is characterized in that: described step 3) in reprocessing for water centrifuge washing 3 times, dry at 60 ~ 120 DEG C.

5. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 2, it is characterized in that: the ratio of the amount of substance of manganese dioxide nano-rod and the volume of aniline is: 0.3 ~ 50mmol:30 ~ 250 μ L, the amount of substance proportion of aniline and oxidant is 1:1 ~ 1:4.

6. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 2, is characterized in that: described oxidant be iron chloride, hydrogen peroxide, Potassiumiodate, potassium bichromate, ammonium persulfate, cesium sulfate any one.

7. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 2, is characterized in that: described acid is any one in inorganic acid hydrochloric acid, sulfuric acid, perchloric acid and nitric acid, organic acid dodecyl sodium sulfonate, phytic acid, oxalic acid, citric acid, DBSA, camphorsulfonic acid and naphthalene sulfonic acids.

8. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 2, is characterized in that: the ratio of the volume of aniline and the amount of substance of acid is 30 ~ 250 μ L:1 ~ 5mmol.

9. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 2, it is characterized in that: reducing atmosphere is that by volume percentages is the mist of nitrogen containing 5% hydrogen, surplus, and inert atmosphere is nitrogen, argon gas atmosphere.

10. the preparation method of the coated manganese monoxide composite material of one dimension porous nucleocapsid structure nitrogen-doped carbon according to claim 2, it is characterized in that: high-temperature heat treatment is with the heating rate of 1 ~ 10 DEG C/min, be raised to target temperature 500 ~ 800 DEG C insulation 2 ~ 10 hours.