CN102916188B - Preparation method of hierarchical porous carbon/organo polysulfide/polyaniline composite material - Google Patents

Abstract

The invention relates to the technical field of new energy materials and discloses a preparation method of a hierarchical porous carbon/organo polysulfide/polyaniline composite material. The preparation method is characterized by using hierarchical porous carbon as a carrier and depositing organo polysulfide and polyaniline inside or on the surface of the hierarchical porous carbon by an in-situ oxidative polymerization method to prepare the hierarchical porous carbon/organo polysulfide/polyaniline composite material. The method is simple in process, high in controllability, low in raw material cost and available to raw material, is low in impact on environment during preparation, and is easy for industrial production. The composite material prepared by the method has high discharge specific capacity and excellent charge and discharge cycle performances and can be used as a rechargeable lithium battery cathode material.

Description

Preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material

technical field

The invention relates to the technical field of new energy materials, and relates to a method for preparing a positive electrode material for a secondary lithium battery, in particular to a method for preparing a hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material.

Background technique

Polyorganic polysulfides, a new type of energy storage material, have potential application value as cathode materials for lithium batteries due to their theoretically high capacity and environmental friendliness. In 1988, the National Energy Research Center of the United States (Lawrence Berkeley) reported the metal sodium/polyorganodisulfide battery for the first time [ J. Electrochem. Soc. , Vol. 135, 2905, (1999)]. In the early 1990s, Japanese researchers proposed to use polyorganic polysulfides as positive electrode materials for batteries, among which poly2,5-dimercapto-1,3,4-thiadiazole was the most researched. However, the electrochemical reaction rate of poly 2,5-dimercapto-1,3,4-thiadiazole is slow at room temperature, and the small molecular sulfur mercapto compound generated during discharge is easily soluble in the organic electrolyte, resulting in a stable cycle of the material. Sex is poor.

In order to improve the electrochemical activity and stability of 2,5-dimercapto-1,3,4-thiadiazole, in recent years, people have used conductive polymers, metal nanoparticles, layered compounds and nano-carbon materials to conduct research on it. compound modification. In this regard, N. Oyama et al. prepared dithiol-polyaniline composites, which significantly increased the oxidation reaction rate and specific capacity of dithiol [ Nature , Vol. 373, 598, (1995)]. Chinese patent ZL97109622.8 discloses "a composite material of coordination and complexation of organic disulfide and copper ions". The composite material has high energy density, charge and discharge efficiency and good cycle stability. Chinese patent ZL200910200630.2 discloses "a graphene/poly-2,5-dimercapto-1,3,4-thiadiazole composite material", which is combined with a single poly-2,5-dimercapto-1, Compared with 3,4-thiadiazole, it has better conductivity, and its cycle stability has been improved to a certain extent. However, the electrochemical cycling performance of the polyorganopolysulfide composites obtained by the above modification method is still far from practical application.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a preparation method of hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material, which has the advantages of simple process, strong controllability, environmental friendliness and low cost , the composite material prepared by this method has high specific capacity and good cycle performance, and can meet the requirements of the positive electrode material of the secondary lithium ion battery.

Thinking of the present invention is:

(1) Nano-calcium carbonate aqueous dispersion is used instead of nano-calcium carbonate powder as the secondary pore-forming agent to overcome the defects that nano-calcium carbonate powder is easy to agglomerate and difficult to disperse; phenolic resin is used as the carbon source, and it is carbonized, calcined and etched Obtain hierarchically porous carbon with uniform pore size and interpenetration; using hierarchically porous carbon as a support, poly 2,5-dimercapto-1,3,4-thiadiazole and polyaniline are deposited on hierarchically porous carbon by in-situ chemical oxidative polymerization The inner and surface of the nanopores, and the hierarchical porous carbon/poly 2,5-dimercapto-1,3,4-thiadiazole/polyaniline ternary composite material was prepared.

(2) Introducing polyaniline into the ternary composite material, so that it has high electrical conductivity and can form a charge transfer complex with 2,5-dimercapto-1,3,4-thiadiazole. This is beneficial to increase the electrochemical reaction rate of 2,5-dimercapto-1,3,4-thiadiazole and improve the electrochemical performance of 2,5-dimercapto-1,3,4-thiadiazole .

(3) Hierarchical porous carbon is selected as the carrier, and the hierarchical porous carbon has the characteristics of large specific surface area, high electrical conductivity, strong adsorption capacity and good stability, so as to facilitate the parasitism of active substances and the diffusion of electrolyte, and improve the charge transport performance , thereby improving the cycle stability of the ternary composite. It endows the ternary composite with high specific capacity and good cycle stability.

In order to realize the purpose of the above invention, the present invention adopts the following technical solutions.

A preparation method of hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material is characterized in that it comprises the following steps:

(1) Preparation of hierarchical porous carbon

① After filtering the nano-calcium carbonate aqueous dispersion, washing with absolute ethanol, and then ultrasonically treating it for 2 to 6 hours, the nano-calcium carbonate is evenly dispersed in ethanol to obtain an ethanol dispersion of nano-calcium carbonate;

② Mix the phenolic resin into 10-30wt% ethanol solution, and then mix it with the ethanol dispersion of nano-calcium carbonate obtained in step (1) ① by magnetic stirring, and control the mass ratio of phenolic resin to nano-calcium carbonate to 1:0.3 ~2, get the mixed solution;

③ Volatilize the ethanol in the mixture obtained in step (1)② to obtain light yellow powder;

④ The light yellow powder obtained in step (1) ③ is carbonized and calcined in a tube furnace in an inert gas atmosphere: gradually rise from room temperature to 850°C, control the heating rate at 2-5°C/min, and heat at 300°C , 700°C, and 850°C for 90 minutes, 60 minutes, and 60 minutes, respectively, to obtain calcined products;

⑤ Remove the calcium oxide in the calcined product obtained in step (1) ④ with 0.5-3mol/L hydrochloric acid, then wash with deionized water until neutral, and obtain hierarchical porous carbon after drying;

(2) Preparation of composite materials

① Vacuumize the graded porous carbon obtained in step (1) for 0.5 to 2 hours;

② Add 2,5-dimercapto-1,3,4-thiadiazole alcohol solution and aniline 0.5-2mol/L protonic acid solution under vacuum, and control the concentration of hierarchical pore carbon to 0.5-3mg/mL , stirring for 4 to 24 hours, adding a protonic acid solution of ammonium persulfate under stirring, and stirring and reacting at 25 to 60°C for 12 to 48 hours;

③ Filtration, washing, and drying to obtain the target product——hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material.

Further, the inert gas described in step (1)④ is one of argon or nitrogen.

Further, the alcohol solution described in step (2) ② is one of ethanol or isopropanol.

Further, the protonic acid described in step (2)② is one of sulfuric acid, hydrochloric acid or perchloric acid.

Further, in step (2)②, the molar ratio of 2,5-dimercapto-1,3,4-thiadiazole to aniline is 1:0.2-2.

Further, in step (2)②, the mass ratio of the hierarchical pore carbon to the total amount of 2,5-dimercapto-1,3,4-thiadiazole and aniline is 1:1-5.

Further, in step (2)②, the molar ratio of the ammonium persulfate to the total amount of 2,5-dimercapto-1,3,4-thiadiazole and aniline is 1:0.8-1.5.

The positive effect of the present invention is:

(1) The method of the present invention has the advantages of simple process, strong controllability, cheap and easy-to-obtain raw materials, less impact on the environment during the preparation process, and easy industrial production.

(2) The hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material prepared by the method of the present invention has high discharge specific capacity and good charge-discharge cycle performance, and can be used as anode material for secondary lithium batteries.

Description of drawings

Accompanying drawing 1 is the scanning electron micrograph of the graded hole carbon of the embodiment 1 of the present invention.

Accompanying drawing 2 is the field emission scanning electron microscope photograph of embodiment 1 of the present invention.

Accompanying drawing 3 is the field emission scanning electron micrograph of comparative example 1 of the present invention.

Accompanying drawing 4 is the field emission scanning electron micrograph of comparative example 2 of the present invention.

Accompanying drawing 5 is the discharge capacity-voltage relation graph of the button lithium battery made of positive electrode materials of Example 1 (a), Comparative Example 2 (b) and Comparative Example 1 (c) at a current density of 20mA/g.

Accompanying drawing 6 is the charge-discharge cycle performance diagram of the button lithium battery made of positive electrode materials of Example 1 (a), Comparative Example 2 (b) and Comparative Example 1 (c).

Detailed ways

The specific implementation of the preparation method of the hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material of the present invention will be further introduced below in conjunction with the accompanying drawings, providing 6 examples and 2 comparative examples. However, implementation of the present invention is not limited to the following embodiments.

Example 1

A preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material, comprising the following steps:

(1) Preparation of hierarchical porous carbon

① After filtering the aqueous dispersion of nano-calcium carbonate, washing with absolute ethanol, and then ultrasonically treating it for 6 hours, the nano-calcium carbonate was evenly dispersed in ethanol to obtain an ethanol dispersion of nano-calcium carbonate.

② The phenolic resin is made into 25wt% ethanol solution, and then mixed evenly with the ethanol dispersion of nano-calcium carbonate obtained in step (1) ① by magnetic stirring, and the mass ratio of phenolic resin and nano-calcium carbonate is controlled to be 1: 1.5 to obtain Mixture.

③ Volatilize the ethanol in the mixture obtained in step (1) ② to obtain light yellow powder.

④ The light yellow powder obtained in step (1) ③ is carbonized and calcined in a tube furnace in an argon atmosphere: from room temperature to 300°C at a rate of 2°C/min, and kept at 300°C for 90 minutes; then The temperature was raised from 300°C to 700°C at a rate of 5°C/min, and kept at 700°C for 60 minutes; then the temperature was raised from 700°C to 850°C at a rate of 5°C/min, and kept at 850°C for 60 minutes to obtain a calcined product.

⑤ The calcium oxide in the calcined product obtained in step (1) ④ is removed with 2mol/L hydrochloric acid solution, then washed with deionized water until neutral, and the product obtained after drying is hierarchical porous carbon.

(2) Preparation of composite materials

① Vacuumize 0.5g of the hierarchical porous carbon obtained in step (1) for 1 hour.

② Add 0.75g of 2,5-dimercapto-1,3,4-thiadiazole in 200mL ethanol solution and 0.47g of aniline in 100mL 2mol/L sulfuric acid solution under vacuum, and stir for 12 hours; 50 mL of 2.28 g of ammonium persulfate dissolved in 2 mol/L sulfuric acid solution was added to the above solution, and stirred at 40°C for 24 hours.

③ Filter the product, wash with deionized water and ethanol, and then dry to obtain the target product——hierarchical porous carbon/polyorganic polysulfide (2,5-dimercapto-1,3,4-thiadiazole) / Polyaniline composite.

The product analysis of embodiment 1:

The electrical conductivity of the hierarchically porous carbon/polyorganopolysulfide/polyaniline composite material prepared in Example 1 was measured by a four-probe tester at 0.6 S/cm.

Field emission scanning electron microscopy (FESEM) photos show that the pore size of the hierarchically porous carbon prepared in Example 1 is uniform and interpenetrating (see Figure 1); the hierarchically porous carbon/polyorganic polysulfide/polyaniline conductive composite prepared in Example 1 In the material, part of poly-2,5-dimercapto-1,3,4-thiadiazole/polyaniline forms an interpenetrating network structure with hierarchical porous carbon in a fibrous structure, and some pores of hierarchical porous carbon are also occupied by polymerization products (See Figure 2) This is due to the polymerization of aniline and 2,5-dimercapto-1,3,4-thiadiazole both inside and outside the pores of the hierarchically porous carbon. This structure is not only beneficial to the parasitism of the active material and the diffusion of the electrolyte, but also improves the charge transport performance, which is helpful for improving the cycle stability of poly-2,5-dimercapto-1,3,4-thiadiazole/polyaniline. positive effects.

The graph showing the relationship between discharge capacity and voltage (see accompanying drawing 5, curve a), uses the hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material prepared in Example 1 as the positive electrode material to make the lithium button battery for the first time. The discharge specific capacity is 330.4mAh/g.

The battery charge and discharge cycle performance graph shows (see Figure 6 curve a), the button lithium battery made of the hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material prepared in Example 1 as the positive electrode material after 20 cycles (Voltage range: 1.8～3.8V; current density: 20mA/g; room temperature), the discharge capacity can still maintain nearly 50%.

Comparative example 1--- be the comparative example with embodiment 1

A kind of preparation method of poly 2,5-dimercapto-1,3,4-thiadiazole:

Dissolve 1.5g of 2,5-dimercapto-1,3,4-thiadiazole monomer in a mixed solution of 300mL ethanol and 2mol/L sulfuric acid (the volume ratio of ethanol to sulfuric acid is 2:1), and stir Add 50mL of 2mol/L sulfuric acid solution dissolved with 2.28g of ammonium persulfate into the above solution, stir and react at 40°C for 24 hours, the product is filtered, washed with deionized water and ethanol, and dried to obtain polyorganopoly Sulfide (poly-2,5-dimercapto-1,3,4-thiadiazole).

The product analysis of comparative example 1:

Field emission scanning electron microscope photos (see accompanying drawing 3) show: the polyorganopolysulfide (poly 2,5-dimercapto-1,3,4-thiadiazole) prepared in Comparative Example 1 has a rod-like structure, which indicates that: poly 2,5-Dimercapto-1,3,4-thiadiazole is oriented during polymerization growth.

After testing, the electrical conductivity of the poly 2,5-dimercapto-1,3,4-thiadiazole prepared in Comparative Example 1 was less than 10 ^-8 S/cm.

With the poly 2,5-dimercapto-1,3,4-thiadiazole prepared in comparative example 1 as active material, poly 2,5-dimercapto-1,3,4-thiadiazole, conductive carbon black and The polyvinylidene fluoride binder is mixed in a mass ratio of 80:10:10 to prepare the positive electrode material of the secondary lithium battery. The button lithium battery with the poly 2,5-dimercapto-1,3,4-thiadiazole as the positive electrode material was subjected to a charge-discharge cycle test on the LAND CT2001A battery tester (see Figure 5 curve c), and it was found that the first discharge The specific capacity is 240mAh/g, and the second discharge specific capacity is only 49mAh/g (see Figure 6 curve c). This shows that the cycle performance of the poly 2,5-dimercapto-1,3,4-thiadiazole prepared in Comparative Example 1 is very poor.

Comparative example 2--- be the comparative example with embodiment 1

A method for preparing a hierarchical porous carbon/poly 2,5-dimercapto-1,3,4-thiadiazole composite material, comprising the following steps:

(1) Prepare hierarchical porous carbon (the specific content is the same as that in Example 1).

(2) Preparation of composite materials

① Vacuumize 0.5g of the hierarchical porous carbon obtained in step (1) for 1 hour.

② Quickly add a mixed solution of 1.5g of 2,5-dimercapto-1,3,4-thiadiazole dissolved in 300mL of ethanol and 2mol/L of sulfuric acid in a vacuum state (the volume ratio of ethanol to sulfuric acid is 2:1, ), stirred for 12 hours; under stirring, 50 mL of 2.28 g of ammonium persulfate dissolved in 2 mol/L sulfuric acid solution was added to the above solution, and stirred at 40°C for 24 hours.

③ The product was filtered, washed with deionized water and ethanol, and then dried to obtain the target product—hierarchical porous carbon/poly-2,5-dimercapto-1,3,4-thiadiazole composite material.

The product analysis of comparative example 2:

Measured using a four-probe tester, the electrical conductivity of the hierarchically porous carbon/poly 2,5-dimercapto-1,3,4-thiadiazole composite material prepared in Comparative Example 2 was 0.18 S/cm, which was the same as that in Comparative Example 1. Compared with that, its conductivity has been significantly improved.

Field emission scanning electron microscopy (FESEM) photos (see accompanying drawing 4) show that: the hierarchical porous carbon/poly 2,5-dimercapto-1,3,4-thiadiazole composite material prepared in Comparative Example 2 also has a porous structure, but Some nanopore surfaces and pores are filled with poly-2,5-dimercapto-1,3,4-thiadiazole.

The graph showing the relationship between discharge capacity and voltage (see Figure 5 curve b) shows that the first discharge specific capacity of the button lithium battery made of the positive electrode material of Comparative Example 2 is 291.2mAh/g, compared with Comparative Example 1, its specific capacity has Significantly improved.

The charge-discharge cycle performance diagram of the battery shows (see the curve b in Figure 6) that after 20 cycles of the button lithium battery made of the positive electrode material of Comparative Example 2, the discharge capacity drops rapidly in the first 5 cycles, and then it is relatively stable. The capacity is basically maintained at 33.3%, and compared with Comparative Example 1, the stability has been improved to a certain extent.

The comparison result of embodiment 1 and comparative example 1 and comparative example 2

The hierarchical porous carbon/polyorganopolysulfide (poly2,5-dimercapto-1,3,4-thiadiazole)/polyaniline composite material prepared in Example 1 was compared with the poly2,5- The comparison results of dimercapto-1,3,4-thiadiazole and the hierarchical porous carbon/poly 2,5-dimercapto-1,3,4-thiadiazole composite material prepared in Comparative Example 2 are as follows.

Using the hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material prepared in Example 1 as the positive electrode material, the first discharge specific capacity of the button lithium battery is 330.4mAh/g, which is significantly higher than that of Comparative Example 1 (240mAh/g). and Comparative Example 2 (291.2mAh/g).

The button lithium battery made of the hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material prepared in Example 1 as the positive electrode material can still maintain nearly 50% of the discharge capacity after 20 cycles, which is significantly higher than that of Comparative Example 1 Compared with Comparative Example 2 (33.3%), this can significantly improve the charge-discharge cycle performance of the button lithium battery.

Example 2

A preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material, comprising the following steps:

(1) Preparation of hierarchical porous carbon

① After filtering the aqueous dispersion of nano-calcium carbonate, washing with absolute ethanol, and then ultrasonically treating it for 4 hours, the nano-calcium carbonate is evenly dispersed in ethanol to obtain an ethanol dispersion of nano-calcium carbonate.

② Make the phenolic resin into 10wt% ethanol solution, and then mix it evenly with the ethanol dispersion of nano-calcium carbonate obtained in step (1) ① by magnetic stirring, and control the mass ratio of phenolic resin to nano-calcium carbonate to be 1: 2 to obtain Mixture.

③ Volatilize the ethanol in the mixture obtained in step (1) ② to obtain light yellow powder.

④ The light yellow powder obtained in step (1) ③ is carbonized and calcined in a tube furnace in a nitrogen atmosphere: from room temperature to 300°C at a rate of 3°C/min, and kept at 300°C for 90 minutes; The temperature was raised from 300°C to 700°C at a rate of ℃/min, and kept at 700°C for 60 minutes; then the temperature was raised from 700°C to 850°C at a rate of 5°C/min, and kept at 850°C for 60 minutes to obtain a calcined product.

⑤ Remove the calcium oxide in the calcined product obtained in step (1) ④ with 3mol/L hydrochloric acid solution, then wash with deionized water until neutral, and the product obtained after drying is hierarchical porous carbon.

(2) Preparation of composite materials

① Vacuumize 0.18g of the hierarchical porous carbon obtained in step (1) for 0.5 hours.

② Add 200mL ethanol solution with 0.24g of 2,5-dimercapto-1,3,4-thiadiazole and 100mL of 0.5mol/L hydrochloric acid solution with 0.03g of aniline under vacuum, and stir for 4 hours; Under stirring state, 50 mL of 0.5 mol/L hydrochloric acid solution dissolved with 0.30 g of ammonium persulfate was added to the above solution, and stirred and reacted at 25° C. for 12 hours.

③ The product was filtered, washed with deionized water and ethanol, and then dried to obtain the target product—hierarchical porous carbon/2,5-dimercapto-1,3,4-thiadiazole/polyaniline composite material.

Example 3

A preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material, comprising the following steps:

(1) Preparation of hierarchical porous carbon

① After filtering the aqueous dispersion of nano-calcium carbonate, washing with absolute ethanol, and then ultrasonically treating it for 2 hours, the nano-calcium carbonate is evenly dispersed in ethanol to obtain an ethanol dispersion of nano-calcium carbonate.

② Make the phenolic resin into 30wt% ethanol solution, and then mix with the ethanol dispersion of nano-calcium carbonate obtained in step (1) ① by magnetic stirring, and control the mass ratio of phenolic resin to nano-calcium carbonate to be 1: 0.3 to obtain Mixture.

③ Volatilize the ethanol in the mixture obtained in step (1) ② to obtain light yellow powder.

④ The light yellow powder obtained in step (1) ③ is carbonized and calcined in a tube furnace in an argon atmosphere: from room temperature to 300°C at a rate of 5°C/min, and kept at 300°C for 90 minutes; The temperature was raised from 300°C to 700°C at a rate of 2°C/min, and kept at 700°C for 60 minutes; then the temperature was raised from 700°C to 850°C at a rate of 5°C/min, and kept at 850°C for 60 minutes to obtain a calcined product.

⑤ The calcium oxide in the calcined product obtained in step (1) ④ is removed with 0.5mol/L hydrochloric acid solution, then washed with deionized water until neutral, and the product obtained after drying is hierarchical porous carbon.

(2) Preparation of composite materials

① Vacuumize 0.8g of the hierarchical porous carbon obtained in step (1) for 0.5 hours.

② Add 1.5g of 2,5-dimercapto-1,3,4-thiadiazole in 200mL of ethanol solution and 0.46g of aniline in 100mL of 0.5mol/L sulfuric acid solution under vacuum, and stir for 12 hours; 50 mL of 0.5 mol/L sulfuric acid solution dissolved with 3.42 g of ammonium persulfate was added to the above solution under stirring state, and stirred and reacted at 25° C. for 48 hours.

③ The product was filtered, washed with deionized water and ethanol, and then dried to obtain the target product—hierarchical porous carbon/2,5-dimercapto-1,3,4-thiadiazole/polyaniline composite material.

Example 4

A preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material, comprising the following steps:

(1) Preparation of hierarchical porous carbon

① After filtering the aqueous dispersion of nano-calcium carbonate, washing with absolute ethanol, and then ultrasonically treating it for 4 hours, the nano-calcium carbonate is evenly dispersed in ethanol to obtain an ethanol dispersion of nano-calcium carbonate.

② Make the phenolic resin into 20wt% ethanol solution, and then mix evenly with the ethanol dispersion of nano-calcium carbonate obtained in step (1) ① by magnetic stirring, and control the mass ratio of phenolic resin to nano-calcium carbonate to be 1: 2 to obtain Mixture.

③ Volatilize the ethanol in the mixture obtained in step (1) ② to obtain light yellow powder.

④ The light yellow powder obtained in step (1) ③ is carbonized and calcined in a tube furnace in a nitrogen atmosphere: from room temperature to 300°C at a rate of 2°C/min, and kept at 300°C for 90 minutes; The temperature was raised from 300°C to 700°C at a rate of ℃/min, and kept at 700°C for 60 minutes; then the temperature was raised from 700°C to 850°C at a rate of 5°C/min, and kept at 850°C for 60 minutes to obtain a calcined product.

⑤ Remove the calcium oxide in the calcined product obtained in step (1) ④ with 1mol/L hydrochloric acid solution, then wash with deionized water until neutral, and the product obtained after drying is hierarchical porous carbon.

(2) Preparation of composite materials

① Vacuumize 1g of the hierarchical porous carbon obtained in step (1) for 2 hours.

② Add 200mL isopropanol solution containing 0.75g of 2,5-dimercapto-1,3,4-thiadiazole and 100mL of 0.5mol/L perchloric acid solution containing 0.47g of aniline under vacuum, and stir 24 hours; 50 mL of 1 mol/L perchloric acid solution dissolved with 1.82 g of ammonium persulfate was added to the above solution under stirring, and stirred and reacted at 60° C. for 48 hours.

③ The product was filtered, washed with deionized water and ethanol, and then dried to obtain the target product—hierarchical porous carbon/2,5-dimercapto-1,3,4-thiadiazole/polyaniline composite material.

Example 5

A preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material, comprising the following steps:

(1) Preparation of hierarchical porous carbon

(the same as the step content of the embodiment).

(2) Preparation of composite materials

① Vacuumize 0.5g of the hierarchical porous carbon obtained in step (1) for 2 hours.

② Add 0.9g of 2,5-dimercapto-1,3,4-thiadiazole in 200mL ethanol solution and 1.16g of aniline in 100mL 2mol/L perchloric acid solution under vacuum, and stir for 12 hours; 50 mL of 2 mol/L perchloric acid solution dissolved with 4.1 g of ammonium persulfate was added to the above solution under stirring state, and stirred and reacted at 60° C. for 36 hours.

③ The product was filtered, washed with deionized water and ethanol, and dried to obtain the target product—hierarchical porous carbon/2,5-dimercapto-1,3,4-thiadiazole/polyaniline composite material.

Example 6

A preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material, comprising the following steps:

(1) Preparation of hierarchical porous carbon

(the same as the step content of the embodiment).

(2) Preparation of composite materials

① Vacuumize 0.5g of the hierarchical porous carbon obtained in step (1) for 1 hour.

② Add 0.30g of 2,5-dimercapto-1,3,4-thiadiazole in 200mL of isopropanol solution and 0.37g of aniline in 100mL of 1mol/L hydrochloric acid solution under vacuum, and stir for 12 hours; 50 mL of 1 mol/L hydrochloric acid solution dissolved with 1.37 g of ammonium persulfate was added to the above solution under stirring state, and stirred and reacted at 30° C. for 12 hours.

③ The product was filtered, washed with deionized water and ethanol, and dried to obtain the target product—hierarchical porous carbon/2,5-dimercapto-1,3,4-thiadiazole/polyaniline composite material.

The hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material obtained by the method of the present invention can be used as the positive electrode material of a secondary lithium battery. After the electrode is assembled into a battery with metal lithium, the electrochemical performance is tested as follows :

(1) Preparation of composite electrodes: using hierarchical porous carbon/polyorganopolysulfide/polyaniline conductive composite material and polyorganopolysulfide as active materials, the active materials were bonded with conductive carbon black and polyvinylidene fluoride. The binder was mixed in a mass ratio of 80:10:10, the above mixture was evenly mixed, coated on an aluminum foil, and then dried under vacuum at 70°C for 48 hours to obtain a composite electrode.

(2) Battery assembly: the composite electrode prepared by the above method is used as the positive electrode, the metal lithium sheet is used as the negative electrode, the polyethylene porous film is used as the diaphragm, and the 1mol/L lithium hexafluorophosphorus solution (dimethyl carbonate, ethyl carbonate, etc.) A solution with a volume ratio of 1:1:1 to ethyl methyl carbonate) was used as the electrolyte, and a button cell was assembled in an argon atmosphere glove box.

(3) Battery performance test: the button battery was charged and discharged at a current density of 20mA/g, and the charge and discharge voltage range was 1.8-3.8V.

Claims (3)

1. A preparation method of hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material, is characterized in that, comprises the following steps: (1) Preparation of hierarchical porous carbon ① After filtering the nano-calcium carbonate aqueous dispersion, washing with absolute ethanol, and then ultrasonically treating it for 2 to 6 hours, the nano-calcium carbonate is evenly dispersed in ethanol to obtain an ethanol dispersion of nano-calcium carbonate; ② Mix the phenolic resin into 10-30wt% ethanol solution, and then mix it with the ethanol dispersion of nano-calcium carbonate obtained in step (1) ① by magnetic stirring, and control the mass ratio of phenolic resin to nano-calcium carbonate to 1:0.3 ~2, get the mixed solution; ③ Volatilize the ethanol in the mixture obtained in step (1)② to obtain light yellow powder; ④ The light yellow powder obtained in step (1) ③ is carbonized and calcined in a tube furnace in an inert gas atmosphere: gradually rise from room temperature to 850°C, control the heating rate at 2-5°C/min, and heat at 300°C , 700°C, and 850°C for 90 minutes, 60 minutes, and 60 minutes, respectively, to obtain calcined products; The inert gas is one of argon or nitrogen; ⑤ Remove the calcium oxide in the calcined product obtained in step (1) ④ with 0.5-3mol/L hydrochloric acid, then wash with deionized water until neutral, and obtain hierarchical porous carbon after drying; (2) Preparation of composite materials ① Vacuumize the graded porous carbon obtained in step (1) for 0.5 to 2 hours; ② Add 2,5-dimercapto-1,3,4-thiadiazole alcohol solution and aniline 0.5~2mol/L protonic acid solution under vacuum, control the concentration of hierarchical pore carbon to 0.5~3mg/mL , stirring for 4 to 24 hours, adding a protonic acid solution of ammonium persulfate under stirring, and stirring and reacting at 25 to 60°C for 12 to 48 hours; The mass ratio of the hierarchical porous carbon to the total amount of 2,5-dimercapto-1,3,4-thiadiazole and aniline is 1:1-5; Described alcoholic solution is a kind of in ethanol or Virahol; Described protonic acid is a kind of in sulfuric acid, hydrochloric acid or perchloric acid; ③ Filtration, washing, and drying to obtain the target product——hierarchical porous carbon/polyorganic polysulfide/polyaniline composite material. 2. The preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material according to claim 1, characterized in that, in step (2)②, the 2,5-dimercapto-1, The molar ratio of 3,4-thiadiazole to aniline is 1:0.2~2. 3. The preparation method of hierarchical porous carbon/polyorganopolysulfide/polyaniline composite material according to claim 1, characterized in that, in step (2) ②, the ammonium persulfate and 2,5-di The molar ratio of mercapto-1,3,4-thiadiazole to the total amount of aniline is 1:0.8-1.5.