Preparation method of a multi-metal sulfide hollow nanocage composite material

Abstract

The application relates to the technical field of battery materials, in particular to a preparation method of a multi-metal sulfide hollow nanocage composite material, which comprises the following steps: S1, precursor preparation; S2, sulfidation agent preparation; and S3, composite preparation.In the application, the graphene oxide in the additive component is used as a conductive base material, can provide a macroscopic scale high-speed electron transmission channel, forms a three-dimensional cross-linked polymer conductive network, effectively fills the gaps between the graphene sheet layers, physically prevents the re-stacking of the graphene sheet layers due to the van der Waals force, and significantly enhances the toughness of the overall structure, the doping of the phytic acid can improve the conductivity of the polyaniline molecular chain by using the rich phosphoric acid groups of the phytic acid, and the phytic acid molecules can also be intercalated between the graphene sheet layers to prevent the layer accumulation, cooperatively maintain the high specific surface area and the unblocked ion transmission channel of the composite material, so that the conductivity of the composite material is comprehensively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery materials, in particular to a preparation method of a multi-metal sulfide hollow nanocage composite material. BACKGROUND

[0002] The multi-metal sulfide hollow nanocage composite material is a kind of frontier material with special microstructure and excellent performance, which has broad application prospects in the field of energy storage and conversion. The core advantage is that the transition metal sulfide is prepared into a nanocage with a hollow structure, which can significantly increase the specific surface area and expose more electrochemical active sites, thereby providing higher specific capacity and excellent rate performance. Usually, such materials are prepared by using metal-organic frameworks as precursors through template method or in-situ sulfuration method.

[0003] In the prior art, during the preparation of the multi-metal sulfide hollow nanocage composite material, the sheets of graphene oxide and other conductive components are prone to uncontrollable restacking and aggregation due to van der Waals force, which leads to the blockage of effective ion transmission channels, the lengthening and discontinuity of electron transmission paths, and the inability to form a high-efficiency and stable three-dimensional conductive network inside the composite material, resulting in a decrease in the conductivity. Based on this, the present application provides a preparation method of a multi-metal sulfide hollow nanocage composite material. SUMMARY

[0004] The present application aims to provide a preparation method of a multi-metal sulfide hollow nanocage composite material. The multi-metal sulfide hollow nanocage composite material prepared by the present application not only has good material structure performance, but also has good electrochemical performance.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a preparation method of a multi-metal sulfide hollow nanocage composite material, comprising the following steps:

[0006] S1: precursor preparation, the raw materials of the precursor include cobalt nitrate hexahydrate, nickel nitrate hexahydrate, deionized water, 2-methyl imidazole, and an additive, and the raw materials of the additive include graphene oxide, aniline, phytic acid, deionized water, and ammonium persulfate;

[0007] S2: preparation of a sulfuration agent, the raw materials of the sulfuration agent include sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol;

[0008] S3: composite preparation, the precursor and the sulfuration agent are compounded to prepare a multi-metal sulfide hollow nanocage composite material.

[0009] Preferably, the method for preparing the precursor is as follows: cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and deionized water are added into a mixer, the mixer is set to 60-80 rpm for stirring for 10-20 min, then the additive and 2-methylimidazole are added into the mixer, and stirring is continued for 2-3 h, the obtained product is sent into a centrifuge, the centrifuge is set to 6000-8000 rpm for centrifugal treatment for 6-10 min, the precipitate is obtained after centrifugal treatment, the precipitate is washed with methanol for 4-6 times, the obtained product is sent into an oven, the oven is set to 40-50℃ for drying for 2-3 h, then the temperature is increased to 50-60℃, and drying is performed for 1-2 h, thereby obtaining the precursor.

[0010] Preferably, the mass ratio of cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and deionized water is 1:1:6-8, the mass of the additive is 2-4% of the mass of deionized water, and the mass of 2-methylimidazole is 1-2% of the mass of deionized water.

[0011] Preferably, the additive is prepared by the following method: graphene oxide, aniline, phytic acid, and multi-walled carbon nanotubes are dispersed in deionized water, and then standing for 20-40 min, followed by ultrasonic treatment for 10-20 min, the obtained product is placed in a water bath, ammonium persulfate is added into the water bath under ice water bath conditions, and reaction is performed for 2-4 h, the obtained product is sent into a centrifuge, the centrifuge is set to 8000-10000 rpm for centrifugal treatment for 6-10 min, the solid obtained after centrifugal treatment is washed with deionized water, and the obtained product is sent into a vacuum drying box, the vacuum drying box is set to 60-70℃ for drying for 4-6 h, thereby obtaining the additive.

[0012] Preferably, the mass ratio of graphene oxide, aniline, phytic acid, multi-walled carbon nanotubes, and deionized water is 1:3-5:0.4-0.6:0.2-0.4:6-8, and the mass of ammonium persulfate is 6-8% of the mass of graphene oxide.

[0013] Preferably, the method for preparing the vulcanizing agent is as follows: sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol are added into a ball mill, which is set to 200-300 rpm for ball milling for 3-5 h, the obtained product is sent into a vacuum drying box, the vacuum drying box is set to 60-70℃ for drying for 6-8 h, the obtained product is sent into a water bath, the water bath temperature is set to 65-75℃, and heat preservation is performed for 1-2 h, oscillation treatment is performed every 15 min during heat preservation, after cooling to room temperature, the obtained product is ground, thereby obtaining the vulcanizing agent.

[0014] Preferably, the mass ratio of sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol is 1:1:0.1-0.2:4-6.

[0015] Preferably, the five water sodium thiosulfate, calcium sulfate dihydrate, activated clay are pre-dried before preparing the vulcanizing agent, the treatment temperature is 80-90 DEG C, and the time is 8-10h.

[0016] Preferably, the method for preparing the composite is as follows: the precursor, the vulcanizing agent and deionized water are added into a mixer, the mixer is set to 80-100 rpm for stirring for 20-40 min, the obtained product is transferred into a reaction kettle, the reaction kettle is set to 80-90 DEG C for heat preservation for 40-60 min, then the temperature is raised to 180-220 DEG C at a rate of 4-6 DEG C / min, and heat preservation is carried out for 8-10h, after cooling to room temperature, the obtained product is added into a centrifuge, the centrifuge is set to 8000-10000 rpm for centrifugal treatment for 6-10 min, the solid obtained by centrifugal treatment is washed 4-6 times alternately with deionized water and ethanol, and the obtained product is sent into a vacuum drying box, the vacuum drying box is set to 55-65 DEG C for drying for 6-8h, the composite preparation is completed, and the multi-metal sulfide hollow nanocage composite material is prepared.

[0017] Preferably, the mass ratio of the precursor, the vulcanizing agent and deionized water is 1:2-3:6-8.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1、In the present application, the graphene oxide in the additive component can provide a macro-scale electron high-speed transmission channel, the polyaniline can be in-situ polymerized between the graphene oxide layers to form a three-dimensional cross-linked polymer conductive network, effectively filling the gap between the graphene layers, physically preventing the re-stacking of the graphene layers due to van der Waals force, and significantly enhancing the toughness of the overall structure, the doping of phytic acid can improve the conductivity of the polyaniline molecular chain by using the rich phosphoric acid groups, and the phytic acid molecules can also intercalate between the graphene layers to prevent the stacking of the layers, thereby synergistically maintaining the high specific surface area and smooth ion transmission channel of the composite material, and comprehensively improving the conductivity of the composite material, and the addition of the multi-walled carbon nanotubes can provide an additional electron transmission path, form a cross-linked network structure with the graphene oxide, enhance the correlation of the material and prevent the stacking of the material, and further improve the conductivity of the composite material.

[0020] In the subsequent vulcanization and heat treatment process, the additives can be partially reduced and carbonized to form a nitrogen and phosphorus co-doped porous carbon network together with the carbon produced by the pyrolysis of the metal material framework, thereby tightly wrapping and connecting the metal sulfide nanoparticles, greatly reducing the interface contact resistance, and providing an ideal path for the rapid transmission of electrons and ions.

[0021] 2、In the present application, during the subsequent vulcanization and heat treatment process, the additive can be partially reduced and carbonized, and the carbonaceous material produced by the pyrolysis of the metal material frame precursor forms a nitrogen and phosphorus co-doped porous carbon network together with the carbonaceous material, which can tightly wrap and connect the metal sulfide nanoparticles generated by the vulcanization reaction, greatly reducing the interface contact resistance, not only providing an excellent electron conduction path, but also providing an ideal channel for the rapid migration of ions, ultimately creating a synergistically optimized ideal path for the rapid transmission of electrons and ions inside the electrode material, significantly improving the rate performance and cycle stability of the composite material. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A flowchart of a preparation method of a multi-metal sulfide hollow nanocage composite material is proposed for the present application;

[0023] Figure 2 A scanning electron microscope image of a multi-metal sulfide hollow nanocage composite material is proposed for the present application, wherein Figure (a) is a scanning electron microscope image of a multi-metal sulfide hollow nanocage composite material prepared in Example 1, Figure (b) is a scanning electron microscope image of a multi-metal sulfide hollow nanocage composite material prepared in Comparative Example 2, and Figure (c) is a scanning electron microscope image of a multi-metal sulfide hollow nanocage composite material prepared in Comparative Example 1. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0025] It should be noted that the raw materials used in the following examples are commercially available.

[0026] Example 1:

[0027] A preparation method of a multi-metal sulfide hollow nanocage composite material includes the following steps:

[0028] S1: Preparation of a precursor, the raw materials of the precursor include cobalt nitrate hexahydrate, nickel nitrate hexahydrate, deionized water, 2-methyl imidazole, and an additive, the raw materials of the additive include graphene oxide, aniline, phytic acid, deionized water, and ammonium persulfate;

[0029] The method for preparing the precursor is: the cobalt nitrate hexahydrate, the nickel nitrate hexahydrate and the deionized water are added into a mixer at a mass ratio of 1:1:6, the mixer is set to 60 rpm for stirring for 10 min, then the additive and the 2-methylimidazole are added into the mixer, and the stirring is continued for 2 h, the obtained product is sent into a centrifuge, the centrifuge is set to 6000 rpm for centrifugal treatment for 6 min, the precipitate is obtained after the centrifugal treatment, the precipitate is washed with methanol for 4 times, the obtained product is sent into an oven, the oven is set to 40 DEG C for drying treatment for 2 h, then the temperature is increased to 50 DEG C, and the drying treatment is performed for 1 h, and the precursor is prepared, wherein the mass of the additive is 2% of the mass of the deionized water, and the mass of the 2-methylimidazole is 1% of the mass of the deionized water.

[0030] S2: preparation of a vulcanizing agent, raw materials of the vulcanizing agent include sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay and anhydrous ethanol;

[0031] The method for preparing the vulcanizing agent is: the sodium thiosulfate pentahydrate, the calcium sulfate dihydrate, the activated clay and the anhydrous ethanol are added into a ball mill at a mass ratio of 1:1:0.1:4, and the ball mill is set to 200 rpm for ball milling treatment for 3 h, the obtained product is sent into a vacuum drying box, the vacuum drying box is set to 60 DEG C for drying treatment for 6 h, the obtained product is sent into a water bath, the water bath temperature is set to 65 DEG C, and the obtained product is treated by oscillation every 15 min during the heat preservation for 1 h, after the obtained product is cooled to room temperature, the obtained product is treated by grinding, and the vulcanizing agent is prepared.

[0032] S3: composite preparation, the precursor and the vulcanizing agent are subjected to composite preparation, and the multi-metal sulfide hollow nanocage composite material is prepared.

[0033] The method for the composite preparation is: the precursor, the vulcanizing agent and the deionized water are added into a mixer at a mass ratio of 1:2:6, the mixer is set to 80 rpm for stirring treatment for 20 min, the obtained product is transferred into a reaction kettle, the reaction kettle is set to 80 DEG C for heat preservation for 40 min, then the temperature increasing rate is set to 4 DEG C / min, the temperature is increased to 180 DEG C, and the heat preservation is performed for 8 h, after the obtained product is cooled to room temperature, the obtained product is added into a centrifuge, the centrifuge is set to 8000 rpm for centrifugal treatment for 6 min, the solid obtained after the centrifugal treatment is washed with the deionized water and the ethanol alternately for 4 times, the obtained product is sent into a vacuum drying box, the vacuum drying box is set to 55 DEG C for drying treatment for 6 h, the composite preparation is completed, and the multi-metal sulfide hollow nanocage composite material is prepared.

[0034] The additive is prepared by the following method: graphene oxide, aniline, phytic acid, and multi-walled carbon nanotubes are dispersed in deionized water, and then left to stand for 20 min, and then ultrasonic treatment is performed for 10 min, the obtained product is placed in a water bath, and under the condition of ice water bath, ammonium persulfate is added to the water bath, and the reaction is performed for 2 h, the obtained product is placed in a centrifuge, the centrifuge is set to 8000 rpm for centrifugal treatment for 6 min, the solid obtained by centrifugal treatment is washed with deionized water, and the obtained product is placed in a vacuum drying oven, the vacuum drying oven is set to 60 DEG C for drying treatment for 4 h, and the additive is prepared, wherein the mass ratio of graphene oxide, aniline, phytic acid, multi-walled carbon nanotubes, and deionized water is 1:3:0.4:0.2:6, and the mass of ammonium persulfate is 6% of the mass of graphene oxide.

[0035] The sodium thiosulfate pentahydrate, calcium sulfate dihydrate, and activated clay are pre-dried before preparing the vulcanizing agent, the treatment temperature is 80 DEG C, and the time is 8 h.

[0036] Example 2:

[0037] A preparation method of a multi-metal sulfide hollow nanocage composite material, comprising the following steps:

[0038] S1: precursor preparation, the raw materials of the precursor include cobalt nitrate hexahydrate, nickel nitrate hexahydrate, deionized water, 2-methyl imidazole, and an additive, the raw materials of the additive include graphene oxide, aniline, phytic acid, deionized water, and ammonium persulfate;

[0039] The method for preparing the precursor is as follows: the cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and deionized water are added to a mixer at a mass ratio of 1:1:7, the mixer is set to 70 rpm for stirring treatment for 15 min, then the additive and 2-methyl imidazole are added to the mixer, and the stirring treatment is continued for 2.5 h, the obtained product is placed in a centrifuge, the centrifuge is set to 7000 rpm for centrifugal treatment for 8 min, the precipitate is obtained after centrifugal treatment, the precipitate is washed with methanol for 5 times, and the obtained product is placed in an oven, the oven is set to 45 DEG C for drying treatment for 2.5 h, and then the temperature is increased to 55 DEG C for drying treatment for 1.5 h, and the precursor is prepared, wherein the mass of the additive is 3% of the mass of the deionized water, and the mass of 2-methyl imidazole is 1.5% of the mass of the deionized water.

[0040] S2: preparation of a vulcanizing agent, the raw materials of the vulcanizing agent include sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol;

[0041] The method for preparing the vulcanizing agent is as follows: sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol are added into a ball mill at a mass ratio of 1:1:0.15:5, and a ball milling treatment is performed at 250 rpm for 4 h. The obtained product is sent into a vacuum drying box, and a drying treatment is performed at 65℃ for 7 h. The obtained product is sent into a water bath, and the water bath temperature is set to 70℃. The product is kept at this temperature for 1.5 h, and oscillation treatment is performed every 15 min during the keeping process. After the product is cooled to room temperature, the product is ground to obtain the vulcanizing agent.

[0042] S3: composite preparation, the precursor is combined with the vulcanizing agent to obtain the multi-metal sulfide hollow nanocage composite material.

[0043] The method for composite preparation is as follows: the precursor, the vulcanizing agent, and deionized water are added into a mixer at a mass ratio of 1:2.5:7, and a stirring treatment is performed at 90 rpm for 30 min. The obtained product is transferred into a reaction kettle, and the temperature of the reaction kettle is set to 85℃. The product is kept at this temperature for 50 min, and then the temperature is increased to 200℃ at a rate of 5℃ / min, and the product is kept at this temperature for 9 h. After the product is cooled to room temperature, the product is added into a centrifuge, and a centrifugal treatment is performed at 9000 rpm for 8 min. The solid obtained by the centrifugal treatment is washed with deionized water and ethanol alternately for 5 times. The obtained product is sent into a vacuum drying box, and a drying treatment is performed at 60℃ for 7 h to complete the composite preparation, thereby obtaining the multi-metal sulfide hollow nanocage composite material.

[0044] The additive is prepared by the following method: graphene oxide, aniline, phytic acid, and multi-walled carbon nanotubes are dispersed in deionized water, and then left to stand for 30 min. After that, an ultrasonic treatment is performed for 15 min. The obtained product is placed into a water bath, and ammonium persulfate is added into the water bath under ice water bath conditions. The reaction is performed for 3 h. The obtained product is added into a centrifuge, and a centrifugal treatment is performed at 9000 rpm for 8 min. The solid obtained by the centrifugal treatment is washed with deionized water. The obtained product is sent into a vacuum drying box, and a drying treatment is performed at 65℃ for 5 h to obtain the additive. The mass ratio of graphene oxide, aniline, phytic acid, multi-walled carbon nanotubes, and deionized water is 1:4:0.5:0.3:7. The mass of ammonium persulfate is 7% of the mass of graphene oxide.

[0045] The sodium thiosulfate pentahydrate, calcium sulfate dihydrate, and activated clay are pre-dried before being used to prepare the vulcanizing agent. The treatment temperature is 85℃, and the treatment time is 9 h.

[0046] Example 3:

[0047] A method for preparing a multi-metal sulfide hollow nanocage composite material includes the following steps:

[0048] S1: precursor preparation, the raw materials of the precursor include cobalt nitrate hexahydrate, nickel nitrate hexahydrate, deionized water, 2-methylimidazole, and an additive, and the raw materials of the additive include graphene oxide, aniline, phytic acid, deionized water, and ammonium persulfate;

[0049] The method for preparing the precursor is as follows: cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and deionized water are added into a mixer at a mass ratio of 1:1:8, the mixer is set to stir at 80 rpm for 20 min, then the additive and 2-methylimidazole are added into the mixer, and stirring is continued for 3 h, the obtained product is sent into a centrifuge, the centrifuge is set to centrifugal treatment at 8000 rpm for 10 min, the precipitate is obtained after centrifugal treatment, the precipitate is washed with methanol for 6 times, the obtained product is sent into an oven, the oven is set to drying treatment at 50℃ for 3 h, then the temperature is increased to 60℃, and drying treatment is performed for 2 h, thereby the precursor is prepared, wherein the mass of the additive is 4% of the mass of the deionized water, and the mass of 2-methylimidazole is 2% of the mass of the deionized water.

[0050] S2: preparation of a vulcanizing agent, the raw materials of the vulcanizing agent include sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol;

[0051] The method for preparing the vulcanizing agent is as follows: sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol are added into a ball mill at a mass ratio of 1:1:0.2:6, the ball mill is set to ball milling treatment at 300 rpm for 5 h, the obtained product is sent into a vacuum drying box, the vacuum drying box is set to drying treatment at 70℃ for 8 h, the obtained product is sent into a water bath, the water bath temperature is set to 75℃, and heat preservation is performed for 2 h, oscillation treatment is performed every 15 min during the heat preservation, after the obtained product is cooled to room temperature, the obtained product is ground, thereby the vulcanizing agent is prepared.

[0052] S3: composite preparation, the precursor and the vulcanizing agent are subjected to composite preparation, thereby the multi-metal sulfide hollow nanocage composite material is prepared.

[0053] The method for composite preparation is as follows: the precursor, the vulcanizing agent, and deionized water are added into a mixer at a mass ratio of 1:3:8, the mixer is set to stirring treatment at 100 rpm for 40 min, the obtained product is transferred into a reaction kettle, the reaction kettle is set to a temperature of 90℃, heat preservation is performed for 60 min, then the temperature increasing rate is set to 6℃ / min, the temperature is increased to 220℃, and heat preservation is performed for 10 h, after the obtained product is cooled to room temperature, the obtained product is added into a centrifuge, the centrifuge is set to centrifugal treatment at 10000 rpm for 10 min, the solid obtained after centrifugal treatment is washed with deionized water and ethanol alternately for 6 times, the obtained product is sent into a vacuum drying box, the vacuum drying box is set to drying treatment at 65℃ for 8 h, thereby the composite preparation is completed, and the multi-metal sulfide hollow nanocage composite material is prepared.

[0054] The additive is prepared by the following method: graphene oxide, aniline, phytic acid, and multi-walled carbon nanotubes are dispersed in deionized water, and then left to stand for 40 min, followed by ultrasonic treatment for 20 min. The obtained product is placed in a water bath, and ammonium persulfate is added to the water bath under ice water bath conditions. The reaction is carried out for 2-4 h. The obtained product is placed in a centrifuge, and the centrifuge is set to 10,000 rpm for centrifugal treatment for 10 min. The solid obtained by centrifugal treatment is washed with deionized water. The obtained product is placed in a vacuum drying oven, and the vacuum drying oven is set to 70°C for drying treatment for 6 h. The additive is prepared, wherein the mass ratio of graphene oxide, aniline, phytic acid, multi-walled carbon nanotubes, and deionized water is 1:5:0.6:0.4:8, and the mass of ammonium persulfate is 8% of the mass of graphene oxide.

[0055] The sodium thiosulfate pentahydrate, calcium sulfate dihydrate, and activated clay are pre-dried before preparing the vulcanizing agent, and the treatment temperature is 90°C and the treatment time is 10 h.

[0056] Comparative Example 1, the difference between the comparative example and Example 1 is that the comparative example does not contain an additive.

[0057] Comparative Example 2, the difference between the comparative example and Example 1 is that the comparative example does not add activated clay during the preparation of the sulfide.

[0058] Comparative Example 3, the difference between the comparative example and Example 1 is that the comparative example does not add nickel nitrate hexahydrate during the preparation of the precursor.

[0059] Performance test: the performance of the composite material samples prepared in Examples 1-3 and Comparative Examples 1-3 is tested.

[0060] Specific surface area test: the test is carried out in accordance with the standard GB / T19587-2017, and the obtained data is recorded in Table 1.

[0061] Average pore size test: the test is carried out in accordance with the standard GB / T19587-2017, and the obtained data is recorded in Table 1.

[0062] Electrochemical performance test: the specific capacitance (F / g) is tested at 1 A / g by constant current charge and discharge method, and recorded in Table 2. The capacitance retention rate is tested at 5 A / g, the rate performance is obtained, and recorded in Table 2. The capacity retention rate is tested by 5000 times of cyclic charge and discharge at 10 A / g, and recorded in Table 2.

[0063] Table 1:

[0064]

[0065] As can be seen from the data in Table 1, the composite material prepared in Examples 1-3 has an ideal structure, a high specific surface area and a moderate pore size, indicating that the material has developed porous channels, because the additive and activated clay have a synergistic effect.

[0066] Referring to Figure 2 As shown in FIG. 1, the surface of the multi-metal sulfide hollow nanocage composite material prepared in Example 1 is rich in pores with moderate pore size and has developed porous channels. Although the surface of the multi-metal sulfide hollow nanocage composite material prepared in Comparative Example 2 also has a rich pore structure, the porous structure is uneven, and there are many positions with uneven pore size. The surface of the multi-metal sulfide hollow nanocage composite material prepared in Comparative Example 1 has a large pore size and poor specific surface area performance.

[0067] Further analysis of the data in Table 1 shows that the specific surface area of Comparative Example 1 without an additive is the lowest, the pore size is the largest, the surface material is dense, the pore channel is thickened, and there are problems of structure collapse and performance bottleneck. This is mainly because the absence of an additive cannot form a three-dimensional conductive network, the van der Waals force causes the graphene oxide layers to stack, blocking the ion channels, the absence of polyaniline makes the electronic transmission path discontinuous, and the absence of phytic acid further loses the effect of inhibiting stacking and doping to improve electrical conductivity.

[0068] The specific surface area and pore size of Comparative Example 2 without activated clay are inferior to those of Comparative Example 3, and there is a problem of pore structure degradation. This shows that activated clay, as a pore-forming agent and structural support agent, is missing, which causes the material to be unable to form a suitable mesoporous structure for ion transmission, the pore channel is narrow and poorly distributed, and the ion diffusion resistance is increased.

[0069] Table 2:

[0070]

[0071] As can be seen from the data in Table 2, the specific capacitance, rate performance and cycle stability of the composite materials prepared in Examples 1-3 are better than those of Comparative Examples 1-3.

[0072] Further analysis of the data in Table 2 shows that Comparative Example 1 has the worst performance, indicating that the three-dimensional conductive network formed by the additive is the core of high performance, and the electronic transmission is blocked, causing the internal resistance to increase and the polarization to be severe under high current.

[0073] The performance of Comparative Example 2 is second, and although the specific capacitance is good, the rate performance is insufficient, indicating the importance of ion transmission. The optimized pore channel formed by the absence of activated clay causes a bottleneck for ion diffusion.

[0074] The specific capacitance of Comparative Example 3 is slightly lower than that of Comparative Example 2, and the other performances are only inferior to those of Examples 1-3, indicating that the synergistic effect of the double metal can provide more active sites.

[0075] Table 2, comparative example 1 has the worst stability, which indicates that the carbon network without the additive cannot protect the active material from pulverization and peeling off during cycling, resulting in a sharp decrease in capacity, and comparative example 2 has insufficient stability, which indicates that the unsatisfactory pore structure leads to local stress concentration, accelerating the structure decay, while the stability performance of examples 1-3 is outstanding, because the additive-derived nitrogen and phosphorus co-doped carbon layer including sulfide particles can inhibit pulverization and maintain electrical contact, thereby maintaining excellent capacity retention.

[0076] By comparison and analysis of the relevant data in the table, it can be seen that the multi-metal sulfide hollow nanocage composite material prepared by the application not only has good material structure performance, but also has good electrochemical performance. Therefore, it is shown that the multi-metal sulfide hollow nanocage composite material provided by the application has a wider market prospect and is more suitable for promotion.

[0077] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0078] The preferred embodiments of the application disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details, nor limit the application to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of the present specification. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the application, so that those skilled in the art can well understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a multi-metal sulfide hollow nanocage composite material, characterized in that: The method comprises the following steps: S1: precursor preparation, the raw materials of the precursor include cobalt nitrate hexahydrate, nickel nitrate hexahydrate, deionized water, 2-methyl imidazole, and an additive, and the raw materials of the additive include graphene oxide, aniline, phytic acid, deionized water, and ammonium persulfate; S2: sulfidation agent preparation, the raw materials of the sulfidation agent include sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol; S3: composite preparation, the precursor is compounded with the sulfidation agent to prepare a multi-metal sulfide hollow nanocage composite material; The method for preparing the precursor is as follows: cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and deionized water are added into a mixer, the mixer is set to 60-80 rpm for stirring for 10-20 min, then the additive and 2-methyl imidazole are added into the mixer, and stirring is continued for 2-3 h; the obtained product is sent into a centrifugal machine, the centrifugal machine is set to 6000-8000 rpm for centrifugal treatment for 6-10 min; after centrifugal treatment, the precipitate is obtained, the precipitate is washed with methanol for 4-6 times, the obtained product is sent into an oven, the oven is set to 40-50 DEG C for drying for 2-3 h, then the temperature is increased to 50-60 DEG C, and drying is performed for 1-2 h to obtain the precursor; the mass ratio of cobalt nitrate hexahydrate, nickel nitrate hexahydrate, and deionized water is 1:1:6-8, the mass of the additive is 2-4% of the mass of deionized water, and the mass of 2-methyl imidazole is 1-2% of the mass of deionized water; The additive is prepared by the following method: graphene oxide, aniline, phytic acid, and multi-walled carbon nanotubes are dispersed in deionized water, and then the mixture is left to stand for 20-40 min, and then ultrasonic treatment is performed for 10-20 min; the obtained product is placed in a water bath, and under the condition of ice water bath, ammonium persulfate is added into the water bath, and reaction is performed for 2-4 h; the obtained product is sent into a centrifugal machine, the centrifugal machine is set to 8000-10000 rpm for centrifugal treatment for 6-10 min, the obtained solid is washed with deionized water, and the obtained product is sent into a vacuum drying box, the vacuum drying box is set to 60-70 DEG C for drying for 4-6 h to obtain the additive; the mass ratio of graphene oxide, aniline, phytic acid, multi-walled carbon nanotubes, and deionized water is 1:3-5:0.4-0.6:0.2-0.4:6-8, and the mass of ammonium persulfate is 6-8% of the mass of graphene oxide; The method for preparing the sulfidation agent is as follows: sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol are added into a ball mill, and ball milling is performed at 200-300 rpm for 3-5 h; the obtained product is sent into a vacuum drying box, the vacuum drying box is set to 60-70 DEG C for drying for 6-8 h; the obtained product is sent into a water bath, the water bath temperature is set to 65-75 DEG C, and the mixture is kept for 1-2 h; during the keeping, the mixture is oscillated every 15 min; after the mixture is cooled to room temperature, the obtained product is ground to obtain the sulfidation agent; the mass ratio of sodium thiosulfate pentahydrate, calcium sulfate dihydrate, activated clay, and anhydrous ethanol is 1:1:0.1-0.2:4-6. The sodium thiosulfate pentahydrate, calcium sulfate dihydrate and activated clay are pre-dried at a temperature of 80-90 DEG C for 8-10 hours before being used as vulcanizing agents; The method for preparing the composite material is as follows: the precursor, vulcanizing agent and deionized water are added into a mixer, the mixer is set to 80-100 rpm for stirring for 20-40 minutes, the obtained product is transferred into a reaction kettle, the reaction kettle is set to 80-90 DEG C for heat preservation for 40-60 minutes, then the temperature is raised at a rate of 4-6 DEG C / min until 180-220 DEG C, heat preservation is carried out for 8-10 hours, after cooling to room temperature, the obtained product is added into a centrifuge, the centrifuge is set to 8000-10000 rpm for centrifugal treatment for 6-10 minutes, the solid obtained by centrifugal treatment is washed with deionized water and ethanol alternately for 4-6 times, the obtained product is sent into a vacuum drying oven, the vacuum drying oven is set to 55-65 DEG C for drying treatment for 6-8 hours, the composite preparation is completed, and the multi-metal sulfide hollow nanocage composite material is prepared, the mass ratio of the precursor, vulcanizing agent and deionized water is 1:2-3:6-8.

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