High specific energy metal chalcogen cathode new energy material and preparation method thereof

Abstract

This application relates to the field of cathode new energy materials technology, specifically to a high-energy-density metal sulfide cathode new energy material and its preparation method. The method includes the following steps: ammonium heptamolybdate is incorporated into polypyrrole, and then polyacrylic acid is grafted onto it to obtain modified polypyrrole; ferric oxide powder is reacted with dopamine hydrochloride, mixed with sublimed sulfur, and heat-treated to obtain FeS2 / C; FeS2 / C is oxidized to obtain modified FeS2 / C; the modified polypyrrole and modified FeS2 / C are dispersed in acetic acid buffer and dried to obtain a hydrogen-bonded precomplex; the hydrogen-bonded precomplex is ultrasonically dispersed in phosphate buffer, freeze-dried, and heat-treated to obtain a porous composite material; the porous composite material is ball-milled with sulfur powder, heat-treated, cooled, and ground to obtain a high-energy-density metal sulfide cathode new energy material. The high-energy-density metal sulfide cathode new energy material and its preparation method provided in this application exhibit high reversible capacity and cycle stability.

Description

Technical Field

[0001] This application relates to the field of cathode new energy materials technology, specifically to a high-energy-density metal sulfide cathode new energy material and its preparation method. Background Technology

[0002] With the rapid development of electric vehicles and large-scale energy storage, unprecedented demands have been placed on the energy density, power density, and cycle life of rechargeable batteries. Among numerous next-generation battery systems, metal sulfide batteries (especially lithium-sulfur batteries) based on conversion reaction mechanisms are considered a highly promising development direction due to the extremely high theoretical specific capacity and natural abundance of their cathode materials (such as sulfur and metal sulfides). However, practical applications face a series of severe challenges. Firstly, the poor conductivity of metal sulfides limits rate performance and capacity utilization. Secondly, there is a significant volume effect: during lithiation / delithiation, metal sulfides undergo significant lattice structure changes and volume expansion. Repeated stress and strain can cause electrode material pulverization and detachment, leading to the loss of connection between the active material and the conductive network, resulting in rapid capacity decay. Thirdly, there is a severe shuttle effect: during discharge, soluble polysulfide intermediates are generated. These intermediates migrate and shuttle between the positive and negative electrodes, causing irreversible loss of active material, low coulombic efficiency, and corrosion of the lithium anode, exacerbating capacity decay and safety hazards. Therefore, there is an urgent need for a cathode material that can solve the problems of capacity decay and poor cycle stability. Summary of the Invention

[0003] To address the aforementioned issues, the purpose of this application is to provide a high-energy-density metal sulfide cathode new energy material and its preparation method. The prepared cathode new energy material has high reversible capacity and cycle stability.

[0004] To achieve the above objectives, this application provides a method for preparing a high-energy-density metal sulfide-based cathode material, comprising the following steps: S1. Dissolve ammonium heptamolybdate in deionized water at 0-2℃, add pyrrole monomer, stir, and then add ammonium persulfate solution dropwise to react. The reaction is carried out under nitrogen protection throughout. Filter, wash, and dry to obtain pretreated polypyrrole powder. Take the pretreated polypyrrole powder and ultrasonically disperse it in N,N-dimethylformamide. Then add acrylic acid and azobisisobutyronitrile to remove oxygen. React for 5-6 hours, then dropwise into diethyl ether. Filter, wash, and dry to obtain modified polypyrrole. In the above process, ammonium persulfate, as a strong oxidant, abstracts electrons from the α-position of pyrrole monomers, initiating a free radical polymerization reaction to form linear polypyrrole chains. The heptamolybdate ions in ammonium heptamolybdate have a large unit volume and are locked in the polymer matrix by steric hindrance, thereby improving the intrinsic electronic conductivity of the polymer. Under the action of free radicals generated by the decomposition of the initiator azobisisobutyronitrile, acrylic acid monomers undergo graft polymerization on the pyrrole rings of the polypyrrole chains to form polypyrrole-polyacrylic acid copolymers, introducing a large number of carboxyl functional groups as anchoring sites for subsequent interfacial bonding.

[0005] S2. Take ferric oxide powder and add it to tris(hydroxymethyl)aminomethane buffer solution, disperse it by sonication, add dopamine hydrochloride and stir at room temperature, centrifuge, wash and dry to obtain solid A, mix solid A with sublimed sulfur and grind for 10-15 minutes, heat treat under N2 gas for 3-4 hours, cool, wash and dry to obtain FeS2 / C. In the above process, dopamine monomers undergo oxidative self-polymerization in Tris buffer to generate polydopamine. Polydopamine is rich in catechol and amino functional groups, which can firmly adhere to the surface of ferric oxide particles through hydrogen bonding, π-π stacking, and coordination to form a uniform coating layer. Sublimed sulfur and ferric oxide undergo anion displacement reaction at high temperature to generate FeS2. At the same time, the polydopamine coating layer is pyrolyzed under an inert atmosphere, undergoing dehydrogenation, deoxygenation, cyclization, and graphitization microcrystal formation processes to form a carbon layer on the material surface, which improves the binding force with FeS2.

[0006] S3. Add FeS2 / C to HNO3 solution, stir, centrifuge, wash, and dry to obtain modified FeS2 / C; take modified polypyrrole and modified FeS2 / C and ultrasonically disperse them in acetic acid buffer, stir, and dry to obtain hydrogen-bonded precomplex; take hydrogen-bonded precomplex and ultrasonically disperse it in phosphate buffer, stir, freeze-dry, and heat-treat to obtain porous composite material. In the above process, dilute HNO3 oxidizes the carbon on the carbon shell surface, generating oxygen-containing functional groups such as carboxyl and hydroxyl groups, providing reaction sites for bonding with modified polypyrrole. Under acidic conditions, the carboxyl groups on the modified polypyrrole chain and the carboxyl / hydroxyl groups generated by oxidation on the FeS2 / C surface are both in a protonated state, forming a large number of hydrogen bond networks through OH…O or OH…N. Under neutral conditions, the carboxyl groups are partially deprotonated to form carboxylate ions. The oxygen atoms in the carboxylate ions have lone pairs of electrons, which can act as electron donors to bond with iron ions on the FeS2 surface. Coordination bonds are formed on the basis of hydrogen bond network, forming stronger and more stable coordination bonds, locking the interface structure. Modified polypyrrole long chains act like molecular glue, bridging multiple FeS2 / C particles through multiple hydrogen bond and coordination bond interaction sites to form preliminary particle clusters. As the number of connection points increases, these particle clusters are further connected to each other through polymer chains, eventually forming a continuous three-dimensional network structure in the entire solution, wrapping water molecules in the network mesh. Subsequently, water is removed by freeze drying, forming a porous composite material with more mesoporous and macroporous structures.

[0007] S4. Take the porous composite material and sulfur powder, ball mill and mix them, then vacuum heat treat them, and after naturally cooling to room temperature, grind them until they pass through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material.

[0008] In the above process, after heat treatment, elemental sulfur melts into liquid sulfur. Driven by capillary force and surface energy, the liquid sulfur, with its good fluidity, penetrates into the pores of the porous composite material. Sulfur molecules are confined in the gaps of the polymer network, and elemental sulfur is efficiently and uniformly loaded into the pre-constructed conductive composite framework as an active material.

[0009] Furthermore, the ammonium heptamolybdate has a molar ratio of 1-2:10-11:10-11 with pyrrole monomer and ammonium persulfate.

[0010] Furthermore, the mass ratio of the acrylic acid and azobisisobutyronitrile to the pretreated polypyrrole powder is 5-6:0.03-0.04:1-2.

[0011] Furthermore, the mass ratio of the dopamine hydrochloride to ferric oxide is 0.5-1.5:2.

[0012] Furthermore, the sublimed sulfur has a mass ratio of 4-5:1 to solid A.

[0013] Furthermore, the modified polypyrrole has a mass ratio of 1-1.5:1 to the modified FeS2 / C.

[0014] Furthermore, the acetic acid buffer has a pH of 4-4.5.

[0015] Furthermore, the phosphate buffer has a pH of 6.8-7.2.

[0016] Furthermore, the freeze-drying process involves rapidly immersing the freezer in liquid nitrogen for 10-15 minutes, then directly placing it in an ultra-low temperature freezer at -70°C to -80°C for 4-5 hours. Then, under a vacuum of 10-30 Pa, the temperature is increased from -70°C to -80°C to -20°C to -10°C at a rate of 0.5-1°C / hour, and drying continues at this temperature for 4-6 hours. Afterward, under a vacuum of 1-10 Pa, the temperature is increased from -20°C to -10°C to 25-30°C at a rate of 1-2°C / hour, and drying continues at this temperature for 4-6 hours.

[0017] Furthermore, the vacuum heat treatment involves raising the temperature from room temperature to 150-155°C at a heating rate of 2-3°C / minute, and then heat-treating under a vacuum of 1-10 Pa for 12 hours.

[0018] This application also provides a method for preparing a high-energy-density metal chalcogenide cathode new energy material, which yields the metal chalcogenide cathode new energy material.

[0019] In summary, this application has the following beneficial effects: The cathode material prepared in this application modifies polypyrrole by doping it with ammonium heptamolybdate to improve its conductivity, ensuring rapid electron transport during charging and discharging, directly enhancing rate performance and capacity utilization. Grafting polyacrylic acid onto the polypyrrole provides abundant carboxyl groups, and the long polymer chain exhibits excellent elasticity, deforming like a spring during charging and discharging with the expansion and contraction of FeS2, releasing micro-stress and mitigating volume expansion. FeS2 provides a high theoretical specific capacity. Surface modification of FeS2 / C generates abundant oxygen-containing functional groups; a carbon layer coating on the FeS2 surface enables internal electron conduction. This modification of polypyrrole further enhances the performance of the modified polypyrrole. The interconnected segments of the polypyrrole chain, in contact with the carbon layer surface, form long-range electronic conduction bridges between all FeS2 / C particles, ensuring the uniform conductivity of the entire electrode. This connects isolated conductive carbon shells into an integrated three-dimensional conductive network, significantly reducing the electrode's internal resistance. The abundant carboxyl groups in the modified polypyrrole form numerous hydrogen bonds with the oxygen-containing functional groups on the modified FeS2 / C surface. Furthermore, the carboxyl groups on the modified polypyrrole can form stable coordination bonds with the iron ions in FeS2 / C, acting as a chemical anchor to firmly fix FeS2 onto the polymer backbone. The strong adsorption of polysulfide intermediates by FeS2 effectively alleviates... The shuttle effect is mitigated by the fact that the polar carboxyl groups on the modified polypyrrole segments can physically adsorb soluble polysulfide intermediates through polar interactions, confining them near the electrode material. First, rapid and reversible initial cross-linking is achieved using hydrogen bonding under acidic conditions, forming a flexible initial network framework. Then, permanent and robust fixation is achieved using coordination bonds, completely locking the structure and endowing it with sufficient mechanical strength to withstand the stress of subsequent processes and electrochemical cycles. This step-by-step strategy avoids stress concentration and uneven assembly that may result from direct strong bonding, achieving a uniform and tough interface construction. Then, through… Rapid freeze-drying creates macropores and mesopores, which, combined with the adsorption of polysulfide intermediates by FeS2, synergistically restrict the shuttle effect. The chemical anchoring and flexible buffering of the polymer, along with the structural integrity of the robust interface, together form a dual defense against capacity decay. The high theoretical capacity of FeS2, the high conductivity of the hybrid network, and the high ion flux of the hierarchical channels work together to achieve high energy density. The material design in this application provides an operable chemical basis for the preparation method, while the preparation method precisely translates the material design concept into a real structure. The synergy between molecular design and macroscopic performance achieves high initial capacity and high cycling stability. Detailed Implementation

[0020] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this invention.

[0021] The raw materials involved in the specific embodiments of this application are analytical grade. In addition, ferric oxide was purchased from Shenzhen Zhongfayuan Biotechnology Co., Ltd., CAS No.: 1309-37-1.

[0022] Example 1 A method for preparing a high-energy-density metal sulfide-based cathode material includes the following steps: S1. Dissolve 0.01 mol ammonium heptamolybdate in 150 mL of deionized water, cool to 0°C in an ice-water bath, add 0.1 mol pyrrole monomer, stir at 250 rpm for 30 minutes, then slowly add ammonium persulfate solution at a rate of 1 mL / min (dissolve 0.1 mol ammonium persulfate in 50 mL of cold water (temperature 0°C), react at 0°C for 12 hours under nitrogen protection throughout, filter, wash alternately with deionized water and anhydrous ethanol 5 times each, and vacuum dry at 60°C for 24 hours (vacuum degree 8 Pa) to obtain pretreated polypyrrole powder; take 5 g of pretreated polypyrrole powder and ultrasonically disperse (power 200 W, time 25 minutes) in 100 mL In N,N-dimethylformamide, 25g of acrylic acid and 0.15g of azobisisobutyronitrile were added. After purging with nitrogen for 15 minutes to remove oxygen, the mixture was reacted at 65℃ and 150rpm for 6 hours. Then, it was dropped into 500mL of diethyl ether, filtered, washed 3 times with diethyl ether, and dried under vacuum at 40℃ for 12 hours to obtain modified polypyrrole. S2. Take 1g of ferric oxide and add it to 400ml of 10mmol / L tris(hydroxymethyl)aminomethane buffer (pH 8.5). Disperse it by sonication (200W) for 30min. Add 0.25g of dopamine hydrochloride and stir at room temperature (100rpm) for 3 hours. Centrifuge to collect the precipitate, wash it 3 times with deionized water, and vacuum dry it at 60℃ for 12 hours to obtain solid A. Mix 1g of solid A with 4g of sublimed sulfur and grind it for 10min. Transfer it to a sealed tube and treat it at 400℃ for 3 hours under N2 atmosphere. Cool it naturally to room temperature, wash it 3 times with 2M HCl, wash it with deionized water until neutral, and vacuum dry it at 60℃ (8Pa) for 12 hours to obtain FeS2 / C. S3. Add 5g of FeS2 / C to 100mL of 3mol / L HNO3 solution, stir in a 60℃ water bath (80rpm) for 2 hours, centrifuge to collect the precipitate, wash with deionized water to pH 5, and vacuum dry at 60℃ for 12 hours to obtain modified FeS2 / C; take 2.5g of modified polypyrrole and 2.5g of modified FeS2 / C and ultrasonically disperse them in 100mL of acetate buffer (pH=4) (power 200W, time 30 minutes), then stir at room temperature (speed 120rpm) for 6 hours, and vacuum dry at 60℃ (vacuum degree 8Pa) for 6 hours to obtain hydrogen-bonded precomplex; take 5g of hydrogen-bonded precomplex and ultrasonically disperse it in 100mL of... Phosphate buffer (pH=6.8), then stirred at room temperature (120 rpm) for 24 hours, freeze-dried (the freeze-drying process involved rapidly immersing the sample in liquid nitrogen for 15 minutes, then directly placing it in an ultra-low temperature freezer at -80°C for 5 hours, then raising the temperature from -80°C to -20°C at a rate of 0.5°C / hour under a vacuum of 10 Pa, and continuing to dry at this temperature for 4 hours, followed by raising the temperature from -20°C to 25°C at a rate of 1°C / hour under a vacuum of 5 Pa, and drying at this temperature for 4 hours), and finally heat-treated at 80°C under vacuum (5 Pa) for 2 hours to obtain a porous composite material; S4. Take 3g of porous composite material and 7g of sulfur powder and ball mill and mix for 2 hours (250rpm, ball-to-material ratio 10:1). Then, heat the mixture from room temperature to 155℃ at a heating rate of 2℃ / min and heat-treat it under vacuum of 5Pa for 12 hours. After naturally cooling to room temperature, grind it through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material.

[0023] Example 2 A method for preparing a high-energy-density metal sulfide-based cathode material includes the following steps: S1. Dissolve 0.02 mol ammonium heptamolybdate in 150 mL of deionized water, cool to 0°C in an ice-water bath, add 0.11 mol pyrrole monomer, stir at 300 rpm for 30 minutes, then slowly add ammonium persulfate solution at a rate of 2 mL / min (0.11 mol ammonium persulfate dissolved in 50 mL of cold water (temperature 0°C), react at 0°C for 12 hours under nitrogen protection throughout, filter, wash alternately with deionized water and anhydrous ethanol 5 times each, and vacuum dry at 60°C for 24 hours (vacuum degree 8 Pa) to obtain pretreated polypyrrole powder; take 8 g of pretreated polypyrrole powder and ultrasonically disperse (power 250 W, time 25 minutes) in 100 mL In N,N-dimethylformamide, 27g of acrylic acid and 0.17g of azobisisobutyronitrile were added. After purging with nitrogen for 15 minutes to remove oxygen, the mixture was reacted at 70℃ and 200rpm for 6 hours. Then, it was dropped into 500mL of diethyl ether, filtered, washed 3 times with diethyl ether, and dried under vacuum at 40℃ for 12 hours to obtain modified polypyrrole. S2. Take 1g of ferric oxide and add it to 400ml of 10mmol / L tris(hydroxymethyl)aminomethane buffer (pH 8.5). Disperse it by sonication (250W) for 30min. Add 0.5g of dopamine hydrochloride and stir at room temperature (150rpm) for 3h. Centrifuge to collect the precipitate, wash it 3 times with deionized water, and vacuum dry it at 60℃ for 12h to obtain solid A. Mix 1g of solid A with 4.5g of sublimed sulfur and grind it for 10min. Transfer it to a sealed tube and treat it at 400℃ for 3h under N2 atmosphere. Cool it naturally to room temperature, wash it 3 times with 2M HCl, wash it with deionized water until neutral, and vacuum dry it at 60℃ (8Pa) for 12h to obtain FeS2 / C. S3. Add 5g of FeS2 / C to 100mL of 3mol / L HNO3 solution, stir in a 60℃ water bath (90rpm) for 2 hours, centrifuge to collect the precipitate, wash with deionized water to pH 5, and vacuum dry at 60℃ for 12 hours to obtain modified FeS2 / C; take 3g of modified polypyrrole and 2.5g of modified FeS2 / C and ultrasonically disperse in 100mL of acetate buffer (pH=4.5) (power 250W, time 30 minutes), then stir at room temperature (135rpm) for 6 hours, and vacuum dry at 60℃ (vacuum degree 8Pa) for 6 hours to obtain hydrogen-bonded precomplex; take 5g of hydrogen-bonded precomplex and ultrasonically disperse (power 250W, time 30 minutes) in 100mL of acetate buffer (pH=4.5 ... for 6 hours to obtain hydrogen-bonded precomplex. L phosphate buffer (pH=7.0), then stirred at room temperature (135 rpm) for 24 hours, freeze-dried (the freeze-drying process involved rapidly immersing the sample in liquid nitrogen for 10 minutes, then directly placing it in an ultra-low temperature freezer at -80°C for 4 hours, then raising the temperature from -80°C to -20°C at a rate of 1°C / hour under a vacuum of 20 Pa, and continuing to dry at this temperature for 4 hours, followed by raising the temperature from -20°C to 25°C at a rate of 2°C / hour under a vacuum of 5 Pa, and drying at this temperature for 4 hours), and finally heat-treated at 80°C under vacuum (5 Pa) for 2 hours to obtain a porous composite material; S4. Take 3g of porous composite material and 7g of sulfur powder and ball mill and mix for 2 hours (300rpm, ball-to-material ratio 10:1). Then, heat the mixture from room temperature to 155℃ at a heating rate of 3℃ / min and heat-treat it under vacuum of 5Pa for 12 hours. After naturally cooling to room temperature, grind it through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material.

[0024] Example 3 A method for preparing a high-energy-density metal sulfide-based cathode material includes the following steps: S1. Dissolve 0.02 mol ammonium heptamolybdate in 150 mL of deionized water, cool to 0°C in an ice-water bath, add 0.11 mol pyrrole monomer, stir at 350 rpm for 25 minutes, then slowly add ammonium persulfate solution at a rate of 2 mL / min (0.11 mol ammonium persulfate dissolved in 50 mL of cold water (temperature 0°C), react at 0°C for 12 hours under nitrogen protection throughout, filter, wash alternately with deionized water and anhydrous ethanol 5 times each, and vacuum dry at 60°C for 24 hours (vacuum degree 8 Pa) to obtain pretreated polypyrrole powder; take 10 g of pretreated polypyrrole powder and ultrasonically disperse (power 300 W, time 20 minutes) in 100 mL In N,N-dimethylformamide, 30g of acrylic acid and 0.2g of azobisisobutyronitrile were added. After purging with nitrogen for 15 minutes to remove oxygen, the mixture was reacted at 75℃ and 250rpm for 6 hours. Then, it was dropped into 500mL of diethyl ether, filtered, washed 3 times with diethyl ether, and dried under vacuum at 40℃ for 12 hours to obtain modified polypyrrole. S2. Take 1g of ferric oxide and add it to 400ml of 10mmol / L tris(hydroxymethyl)aminomethane buffer (pH 8.5). Disperse by sonication (300W) for 30min. Add 0.75g of dopamine hydrochloride and stir at room temperature (200rpm) for 3h. Centrifuge to collect the precipitate, wash it 3 times with deionized water, and vacuum dry it at 60℃ for 12h to obtain solid A. Mix 1g of solid A with 5g of sublimed sulfur and grind it for 10min. Transfer it to a sealed tube and treat it at 400℃ for 3h under N2 atmosphere. Cool it naturally to room temperature, wash it 3 times with 2M HCl, wash it with deionized water until neutral, and vacuum dry it at 60℃ (8Pa) for 12h to obtain FeS2 / C. S3. Add 5g of FeS2 / C to 100mL of 3mol / L HNO3 solution, stir in a 60℃ water bath (100rpm) for 2 hours, centrifuge to collect the precipitate, wash with deionized water to pH 5, and vacuum dry at 60℃ for 12 hours to obtain modified FeS2 / C; take 3.75g of modified polypyrrole and 2.5g of modified FeS2 / C and ultrasonically disperse in 100mL of acetate buffer (pH=4.5) (300W power, 30min), then stir at room temperature (150rpm) for 6 hours, and vacuum dry at 60℃ (8Pa vacuum) for 6 hours to obtain hydrogen-bonded precomplex; take 5g of hydrogen-bonded precomplex and ultrasonically disperse (300W power, 30min) in 100mL of acetate buffer (pH=4.5), then stir at room temperature (150rpm) for 6 hours, and vacuum dry at 60℃ for 6 hours to obtain hydrogen-bonded precomplex; take 5g of hydrogen-bonded precomplex and ultrasonically disperse in 100mL of acetate buffer (pH=4.5) (300W power, 30min) for 6 hours. mL of phosphate buffer (pH=7.2) was stirred at room temperature (150 rpm) for 24 hours, followed by freeze drying (the freeze drying process involved rapidly immersing the sample in liquid nitrogen for 10-15 minutes, then directly placing it in an ultra-low temperature freezer at -80°C for 4 hours, then raising the temperature from -80°C to -20°C at a rate of 1°C / hour under a vacuum of 30 Pa, and continuing to dry at this temperature for 4 hours, followed by raising the temperature from -20°C to 25°C at a rate of 2°C / hour under a vacuum of 5 Pa, and drying at this temperature for 4 hours), and finally heat-treating at 80°C under vacuum (5 Pa) for 2 hours to obtain a porous composite material. S4. Take 3g of porous composite material and 7g of sulfur powder and ball mill and mix for 2 hours (350rpm, ball-to-material ratio 10:1). Then, heat the mixture from room temperature to 155℃ at a heating rate of 3℃ / min and heat-treat it under vacuum of 5Pa for 12 hours. After naturally cooling to room temperature, grind it through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material.

[0025] Compare with Example 1 The difference between this comparative example and Example 3 is that the preparation method of a high-energy-density metal sulfide-based cathode new energy material in this comparative example includes the following steps: S1. Dissolve 0.02 mol ammonium heptamolybdate in 150 mL of deionized water, cool to 0°C in an ice-water bath, add 0.11 mol pyrrole monomer, stir at 350 rpm for 25 minutes, then slowly add ammonium persulfate solution at a rate of 2 mL / min (0.11 mol ammonium persulfate dissolved in 50 mL of cold water (temperature 0°C), react at 0°C for 12 hours under nitrogen protection throughout, filter, wash alternately with deionized water and anhydrous ethanol 5 times each, and vacuum dry at 60°C for 24 hours (vacuum degree 8 Pa) to obtain pretreated polypyrrole powder; take 10 g of pretreated polypyrrole powder and ultrasonically disperse (power 300 W, time 20 minutes) in 100 mL In N,N-dimethylformamide, 30g of acrylic acid and 0.2g of azobisisobutyronitrile were added. After purging with nitrogen for 15 minutes to remove oxygen, the mixture was reacted at 75℃ and 250rpm for 6 hours. Then, it was dropped into 500mL of diethyl ether, filtered, washed 3 times with diethyl ether, and dried under vacuum at 40℃ for 12 hours to obtain modified polypyrrole. S2. Take 1g of ferric oxide and add it to 400ml of 10mmol / L tris(hydroxymethyl)aminomethane buffer (pH 8.5). Disperse by sonication (300W) for 30min. Add 0.75g of dopamine hydrochloride and stir at room temperature (200rpm) for 3h. Centrifuge to collect the precipitate, wash it 3 times with deionized water, and vacuum dry it at 60℃ for 12h to obtain solid A. Mix 1g of solid A with 5g of sublimed sulfur and grind it for 10min. Transfer it to a sealed tube and treat it at 400℃ for 3h under N2 atmosphere. Cool it naturally to room temperature, wash it 3 times with 2M HCl, wash it with deionized water until neutral, and vacuum dry it at 60℃ (8Pa) for 12h to obtain FeS2 / C. S3. Take 3.75g of modified polypyrrole and 2.5g of FeS2 / C and ultrasonically disperse them in 100mL of acetate buffer (pH=4.5) (power 300W, time 30min). Then stir at room temperature (speed 150rpm) for 6 hours, and vacuum dry at 60℃ (vacuum degree 8Pa) for 6 hours to obtain the hydrogen-bonded precomplex. Take 5g of the hydrogen-bonded precomplex and ultrasonically disperse it in 100mL of phosphate buffer (pH=7.2) (power 300W, time 30min). Then stir at room temperature (speed 150rpm) for 24 hours, and cool. Freeze-drying (the freeze-drying process involves rapidly immersing the sample in liquid nitrogen for 10-15 minutes, then directly placing it in an ultra-low temperature freezer at -80°C for 4 hours, followed by raising the temperature from -80°C to -20°C at a rate of 1°C / hour under a vacuum of 30Pa, and continuing to dry at this temperature for 4 hours, then raising the temperature from -20°C to 25°C at a rate of 2°C / hour under a vacuum of 5Pa, and drying at this temperature for 4 hours), followed by heat treatment at 80°C under vacuum (5Pa) for 2 hours to obtain a porous composite material; S4. Take 3g of porous composite material and 7g of sulfur powder and ball mill and mix for 2 hours (350rpm, ball-to-material ratio 10:1). Then, heat the mixture from room temperature to 155℃ at a heating rate of 3℃ / min and heat-treat it under vacuum of 5Pa for 12 hours. After naturally cooling to room temperature, grind it through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material.

[0026] Compare with Example 2 The difference between this comparative example and Example 3 is that the preparation method of a high-energy-density metal sulfide-based cathode new energy material includes the following steps: S1. Dissolve 0.02 mol ammonium heptamolybdate in 150 mL of deionized water, cool to 0°C in an ice-water bath, add 0.11 mol pyrrole monomer, stir at 350 rpm for 25 minutes, then slowly add ammonium persulfate solution at a rate of 2 mL / min (0.11 mol ammonium persulfate dissolved in 50 mL of cold water (temperature 0°C), react at 0°C for 12 hours under nitrogen protection throughout, filter, wash alternately with deionized water and anhydrous ethanol 5 times each, and vacuum dry at 60°C for 24 hours (vacuum degree 8 Pa) to obtain pretreated polypyrrole powder; take 10 g of pretreated polypyrrole powder and ultrasonically disperse (power 300 W, time 20 minutes) in 100 mL In N,N-dimethylformamide, 30g of acrylic acid and 0.2g of azobisisobutyronitrile were added. After purging with nitrogen for 15 minutes to remove oxygen, the mixture was reacted at 75℃ and 250rpm for 6 hours. Then, it was dropped into 500mL of diethyl ether, filtered, washed 3 times with diethyl ether, and dried under vacuum at 40℃ for 12 hours to obtain modified polypyrrole. S2. Take 1g of ferric oxide and add it to 400ml of 10mmol / L tris(hydroxymethyl)aminomethane buffer (pH 8.5). Disperse by sonication (300W) for 30min. Add 0.75g of dopamine hydrochloride and stir at room temperature (200rpm) for 3h. Centrifuge to collect the precipitate, wash it 3 times with deionized water, and vacuum dry it at 60℃ for 12h to obtain solid A. Mix 1g of solid A with 5g of sublimed sulfur and grind it for 10min. Transfer it to a sealed tube and treat it at 400℃ for 3h under N2 atmosphere. Cool it naturally to room temperature, wash it 3 times with 2M HCl, wash it with deionized water until neutral, and vacuum dry it at 60℃ (8Pa) for 12h to obtain FeS2 / C. S3. Add 5g of FeS2 / C to 100mL of 3mol / L HNO3 solution, stir in a 60℃ water bath (100rpm) for 2 hours, centrifuge to collect the precipitate, wash with deionized water to pH 5, and vacuum dry at 60℃ for 12 hours to obtain modified FeS2 / C; take 3.75g of modified polypyrrole and 2.5g of modified FeS2 / C and ultrasonically disperse them in 100mL of acetate buffer (pH=4.5) (300W power, 30 minutes), then stir at room temperature (150rpm) for 6 hours to obtain hydrogen-bonded precomplex; take 5g of hydrogen-bonded precomplex and ultrasonically disperse it in 100mL of phosphate buffer (pH=4.5) (300W power, 30 minutes). H=7.2), then stirred at room temperature (150 rpm) for 24 hours, freeze-dried (the freeze-drying process involves rapidly immersing the sample in liquid nitrogen for 10-15 minutes, then directly placing it in an ultra-low temperature freezer at -80℃ for 4 hours, then raising the temperature from -80℃ to -20℃ at a rate of 1℃ / hour under a vacuum of 30Pa, and continuing to dry at this temperature for 4 hours, then raising the temperature from -20℃ to 25℃ at a rate of 2℃ / hour under a vacuum of 5Pa, and drying at this temperature for 4 hours), and then heat-treated at 80℃ under vacuum (5Pa) for 2 hours to obtain a porous composite material; S4. Take 3g of porous composite material and 7g of sulfur powder and ball mill and mix for 2 hours (350rpm, ball-to-material ratio 10:1). Then, heat the mixture from room temperature to 155℃ at a heating rate of 3℃ / min and heat-treat it under vacuum of 5Pa for 12 hours. After naturally cooling to room temperature, grind it through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material.

[0027] Compare with Example 3 The difference between this comparative example and Example 3 is that the preparation method of a high-energy-density metal sulfide-based cathode new energy material in this comparative example includes the following steps: S1. Dissolve 0.02 mol ammonium heptamolybdate in 150 mL of deionized water, cool to 0°C in an ice-water bath, add 0.11 mol pyrrole monomer, stir at 350 rpm for 25 minutes, then slowly add ammonium persulfate solution at a rate of 2 mL / min (0.11 mol ammonium persulfate dissolved in 50 mL of cold water (temperature 0°C), react at 0°C for 12 hours under nitrogen protection throughout, filter, wash alternately with deionized water and anhydrous ethanol 5 times each, and vacuum dry at 60°C for 24 hours (vacuum degree 8 Pa) to obtain pretreated polypyrrole powder; take 10 g of pretreated polypyrrole powder and ultrasonically disperse (power 300 W, time 20 minutes) in 100 mL In N,N-dimethylformamide, 30g of acrylic acid and 0.2g of azobisisobutyronitrile were added. After purging with nitrogen for 15 minutes to remove oxygen, the mixture was reacted at 75℃ and 250rpm for 6 hours. Then, it was dropped into 500mL of diethyl ether, filtered, washed 3 times with diethyl ether, and dried under vacuum at 40℃ for 12 hours to obtain modified polypyrrole. S2. Take 1g of ferric oxide and add it to 400ml of 10mmol / L tris(hydroxymethyl)aminomethane buffer (pH 8.5). Disperse by sonication (300W) for 30min. Add 0.75g of dopamine hydrochloride and stir at room temperature (200rpm) for 3h. Centrifuge to collect the precipitate, wash it 3 times with deionized water, and vacuum dry it at 60℃ for 12h to obtain solid A. Mix 1g of solid A with 5g of sublimed sulfur and grind it for 10min. Transfer it to a sealed tube and treat it at 400℃ for 3h under N2 atmosphere. Cool it naturally to room temperature, wash it 3 times with 2M HCl, wash it with deionized water until neutral, and vacuum dry it at 60℃ (8Pa) for 12h to obtain FeS2 / C. S3. Add 5g of FeS2 / C to 100mL of 3mol / L HNO3 solution, stir in a 60℃ water bath (100rpm) for 2 hours, centrifuge to collect the precipitate, wash with deionized water to pH 5, and vacuum dry at 60℃ for 12 hours to obtain modified FeS2 / C; take 3.75g of modified polypyrrole and 2.5g of modified FeS2 / C and ultrasonically disperse in 100mL of acetate buffer (pH=4.5) (300W power, 30 minutes), then stir at room temperature (150rpm) for 6 hours, and vacuum dry at 60℃ (8Pa vacuum) for 6 hours to obtain hydrogen-bonded precomplex; take 5g of hydrogen-bonded precomplex and ultrasonically disperse (300W power, 30 minutes)... The sample was added to 100 mL of phosphate buffer (pH=7.2) and stirred at room temperature (150 rpm) for 24 hours. It was then freeze-dried (the freeze-drying process involved cooling the sample to -50°C at a rate of 10°C / min and holding it there for 4 hours; then, under a vacuum of 30 Pa, the temperature was increased from -50°C to -20°C at a rate of 1°C / hour and dried at this temperature for 4 hours; subsequently, under a vacuum of 5 Pa, the temperature was increased from -20°C to 25°C at a rate of 2°C / hour and dried at this temperature for 4 hours). Finally, it was heat-treated at 80°C under vacuum (5 Pa) for 2 hours to obtain the porous composite material. S4. Take 3g of porous composite material and 7g of sulfur powder and ball mill and mix for 2 hours (350rpm, ball-to-material ratio 10:1). Then, heat the mixture from room temperature to 155℃ at a heating rate of 3℃ / min and heat-treat it under vacuum of 5Pa for 12 hours. After naturally cooling to room temperature, grind it through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material.

[0028] Compare with Example 4 The difference between this comparative example and Example 3 is that the preparation method of a high-energy-density metal sulfide-based cathode new energy material in this comparative example includes the following steps: S1. Dissolve 0.02 mol ammonium heptamolybdate in 150 mL of deionized water, cool to 0°C in an ice-water bath, add 0.11 mol pyrrole monomer, stir at 350 rpm for 25 minutes, then slowly add ammonium persulfate solution at a rate of 2 mL / min (0.11 mol ammonium persulfate dissolved in 50 mL of cold water (temperature 0°C), react at 0°C for 12 hours under nitrogen protection throughout, filter, wash alternately with deionized water and anhydrous ethanol 5 times each, and vacuum dry at 60°C for 24 hours (vacuum degree 8 Pa) to obtain pretreated polypyrrole powder; take 10 g of pretreated polypyrrole powder and ultrasonically disperse (power 300 W, time 20 minutes) in 100 mL In N,N-dimethylformamide, 30g of acrylic acid and 0.2g of azobisisobutyronitrile were added. After purging with nitrogen for 15 minutes to remove oxygen, the mixture was reacted at 75℃ and 250rpm for 6 hours. Then, it was dropped into 500mL of diethyl ether, filtered, washed 3 times with diethyl ether, and dried under vacuum at 40℃ for 12 hours to obtain modified polypyrrole. S2. Take 1g of ferric oxide and add it to 400ml of 10mmol / L tris(hydroxymethyl)aminomethane buffer (pH 8.5). Disperse by sonication (300W) for 30min. Add 1g of dopamine hydrochloride and stir at room temperature (200rpm) for 3h. Centrifuge to collect the precipitate, wash it 3 times with deionized water, and vacuum dry it at 60℃ for 12h to obtain solid A. Mix 1g of solid A with 5g of sublimed sulfur and grind it for 10min. Transfer it to a sealed tube and treat it at 400℃ for 3h under N2 atmosphere. Cool it naturally to room temperature, wash it 3 times with 2M HCl, wash it with deionized water until neutral, and vacuum dry it at 60℃ (vacuum degree 8Pa) for 12h to obtain FeS2 / C. S3. Add 5g of FeS2 / C to 100mL of 3mol / L HNO3 solution, stir in a 60℃ water bath (100rpm) for 2 hours, centrifuge to collect the precipitate, wash with deionized water to pH 5, and vacuum dry at 60℃ for 12 hours to obtain modified FeS2 / C; take 3.75g of modified polypyrrole and 2.5g of modified FeS2 / C and ultrasonically disperse in 100mL of acetate buffer (pH=4.5) (300W power, 30min), then stir at room temperature (150rpm) for 6 hours, and vacuum dry at 60℃ (8Pa vacuum) for 6 hours to obtain hydrogen-bonded precomplex; take 5g of hydrogen-bonded precomplex and ultrasonically disperse (300W power, 30min) in 100mL of acetate buffer (pH=4.5), then stir at room temperature (150rpm) for 6 hours, and vacuum dry at 60℃ for 6 hours to obtain hydrogen-bonded precomplex; take 5g of hydrogen-bonded precomplex and ultrasonically disperse in 100mL of acetate buffer (pH=4.5) (300W power, 30min) for 6 hours. mL of phosphate buffer (pH=7.2) was stirred at room temperature (150 rpm) for 24 hours, followed by freeze drying (the freeze drying process involved rapidly immersing the sample in liquid nitrogen for 10-15 minutes, then directly placing it in an ultra-low temperature freezer at -80°C for 4 hours, then raising the temperature from -80°C to -20°C at a rate of 1°C / hour under a vacuum of 30 Pa, and continuing to dry at this temperature for 4 hours, followed by raising the temperature from -20°C to 25°C at a rate of 2°C / hour under a vacuum of 5 Pa, and drying at this temperature for 4 hours), and finally heat-treating at 80°C under vacuum (5 Pa) for 2 hours to obtain a porous composite material. S4. Take 3g of porous composite material and 7g of sulfur powder and ball mill and mix for 2 hours (350rpm, ball-to-material ratio 10:1). Then, heat the mixture from room temperature to 155℃ at a heating rate of 3℃ / min and heat-treat it under vacuum of 5Pa for 12 hours. After naturally cooling to room temperature, grind it through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material.

[0029] Performance testing Functional tests were conducted on a high-energy-density metal sulfide cathode new energy material prepared in Examples 1-3 and Comparative Examples 1-4.

[0030] A high-energy-density metal chalcogenide cathode material prepared in Examples 1-3 and Comparative Examples 1-4 was weighed with SuperP and PVDF at a mass ratio of 8:1:1. First, the binder PVDF was dissolved in N-methylpyrrolidone and stirred until completely dissolved. Then, the conductive agent SuperP was added. P, grind or stir thoroughly, and finally add the prepared positive electrode material. Stir the mixture at high speed in a planetary centrifugal mixer for 3 hours until a uniform, viscous, particle-free slurry is formed. Use a coater to evenly coat the slurry onto aluminum foil, controlling the wet film thickness (200 μm). Place the coated electrode in a forced-air drying oven and pre-dry at 80°C for 2 hours. Then transfer the electrode to a vacuum drying oven and vacuum dry at 120°C for 12 hours. Gently roll the dried electrode with a roller press, and then punch out small round pieces with a diameter of approximately 12-14 mm as the positive electrode. Place the CR2032 battery case on a platform, place the punched positive electrode in it, and add 70 μL of electrolyte (1M LiTFSI in DOL / DME (1:1v / v) with 2% LiNO3) using a pipette. Cover with a Whatman label. GF / D glass fiber separator, then add 30μL electrolyte, carefully place the lithium sheet, then place the spring sheet and gasket in sequence, finally cover with the negative electrode shell, and then seal it. The battery pack is now complete. After that, connect it to the Blue Battery Testing System for testing. Constant current charge-discharge tests were conducted on the newly assembled batteries of a high-energy-density metal sulfide cathode new energy material prepared in Examples 1-3 and Comparative Examples 1-4. The voltage window was 1.0-3.0V vs. Li / Li⁺, and the current density was 0.1C. The batteries were charged and discharged, and the first charge capacity and the first discharge capacity were recorded. The first coulombic efficiency was calculated. Initial coulombic efficiency = (Initial discharge capacity / Initial charge capacity) × 100% Reversible capacity test: The reversible capacity is the discharge capacity recorded after the 5th cycle of the battery. Cyclic stability test: After testing the initial efficiency, the battery is continuously charged and discharged at the same current density. The discharge capacity of the 500th cycle is recorded, and the capacity retention rate of the 500th cycle is calculated. Capacity retention rate = (Discharge capacity at 500th cycle / Discharge capacity at 5th cycle) × 100%; The test results are shown in Table 1: Table 1 Example 1 83.2 1140 85.8 Example 2 85.6 1180 86.7 Example 3 81.5 1110 85.3 Compare with Example 1 79.8 1010 56.8 Compare with Example 2 65.3 635 45.2 Compare with Example 3 70.1 945 71.4 Compare with Example 4 71.5 872 67.2 As shown in Table 1, the high-specific-energy metal sulfide cathode material prepared in this application exhibits high initial coulombic efficiency, high reversible capacity, and high capacity retention, indicating that the embodiments of this application possess high specific energy and high cycling stability, especially Example 2, which shows the best performance. Compared with Example 3, Comparative Example 1 did not undergo nitric acid oxidation surface modification of FeS2 / C. Although the initial capacity was acceptable, the capacity retention was only 56.8%, far lower than that of Example 3, indicating that the material would undergo structural damage during long-term cycling, leading to rapid capacity decay. This shows that Comparative Example 1 is inferior to Example 3. Compared with Example 3, Comparative Example 2 simplified the pH adjustment process and skipped drying, reacting directly under neutral conditions. The components with opposite charges rapidly and unevenly combined, forming agglomerates of uneven size. These agglomerates formed fewer, smaller, and less interconnected pores during subsequent freeze-drying, resulting in damage to the material structure. The first coulombic efficiency dropped to 65.3%, the reversible capacity plummeted to 635 mAh / g, and the capacity retention was only 45.2%, indicating that Comparative Example 2 was inferior to Example 3. Compared with Example 3, Comparative Example 3 changed the freeze-drying conditions, changing rapid freezing to slow freezing, forming macropores, resulting in uneven sulfur loading, weakened physical confinement ability, and worse physical confinement effect on polysulfides. The test results showed that the first coulombic efficiency decreased, and the reversible capacity and capacity retention decreased significantly, indicating that Comparative Example 3 was inferior to Example 3. Compared with Example 3, Comparative Example 4 increased the amount of dopamine hydrochloride, and after carbonization, formed a thicker or denser carbon shell, shielding the FeS2 surface from the chemical adsorption and catalytic activity of polysulfides, affecting the formation of coordination bonds between FeS2 and polymers. The test results showed that the first coulombic efficiency decreased, and the reversible capacity and capacity retention decreased significantly, indicating that Comparative Example 4 was inferior to Example 3.

[0031] The above description is merely an example and illustration of the concept of this application. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the inventive concept or exceed the scope defined in the claims, they should all fall within the protection scope of this application.

Claims

1. A preparation method of a high specific energy metal chalcogen cathode new energy material, characterized in that, Includes the following steps: S1. Dissolve ammonium heptamolybdate in deionized water at 0-2℃, add pyrrole monomer, stir, and then add ammonium persulfate solution dropwise to react. The reaction is carried out under nitrogen protection throughout. Filter, wash, and dry to obtain pretreated polypyrrole powder. Take the pretreated polypyrrole powder and ultrasonically disperse it in N,N-dimethylformamide. Then add acrylic acid and azobisisobutyronitrile to remove oxygen. React for 5-6 hours, then dropwise into diethyl ether. Filter, wash, and dry to obtain modified polypyrrole. S2. Take ferric oxide powder and add it to tris(hydroxymethyl)aminomethane buffer solution, disperse it by sonication, add dopamine hydrochloride and stir at room temperature, centrifuge, wash and dry to obtain solid A, mix solid A with sublimed sulfur and grind for 10-15 minutes, heat treat under N2 gas for 3-4 hours, cool, wash and dry to obtain FeS2 / C. S3. Add FeS2 / C to HNO3 solution, stir, centrifuge, wash, and dry to obtain modified FeS2 / C; take modified polypyrrole and modified FeS2 / C and ultrasonically disperse them in acetic acid buffer, stir, and dry to obtain hydrogen-bonded precomplex; take hydrogen-bonded precomplex and ultrasonically disperse it in phosphate buffer, stir, freeze-dry, and heat-treat to obtain porous composite material. S4. Take the porous composite material and sulfur powder, ball mill and mix them, then vacuum heat treat them, and after naturally cooling to room temperature, grind them until they pass through a 200-mesh sieve to obtain a high-energy-density metal sulfur-based cathode new energy material. 2.The method for preparing a high specific energy metal chalcogen cathode material according to claim 1, characterized in that, The ammonium heptamolybdate has a molar ratio of 1-2:10-11:10-11 with pyrrole monomer and ammonium persulfate.

3. The method for preparing a high-energy-density metal chalcogenide cathode new energy material according to claim 1, characterized in that, The mass ratio of acrylic acid and azobisisobutyronitrile to pretreated polypyrrole powder is 5-6:0.03-0.04:1-2.

4. The method for preparing a high-energy-density metal chalcogenide cathode new energy material according to claim 1, characterized in that, The mass ratio of dopamine hydrochloride to ferric oxide is 0.5-1.5:

2.

5. The preparation method of the high specific energy metal chalcogen cathode new energy material according to claim 1, characterized in that, The sublimed sulfur has a mass ratio of 4-5:1 to solid A. 6.The method for preparing a high specific energy metal chalcogen cathode material according to claim 1, characterized in that, The modified polypyrrole has a mass ratio of 1-1.5:1 to the modified FeS2 / C. 7.The method of claim 1, wherein the method is characterized by, The acetic acid buffer has a pH of 4-4.

5. 8.The method of claim 1, wherein the method is characterized by, The phosphate buffer solution has a pH of 6.8-7.

2.

9. The method for preparing a high-energy-density metal chalcogenide cathode new energy material according to claim 1, characterized in that, The freeze-drying process involves rapidly immersing the freezer in liquid nitrogen for 10-15 minutes, then directly placing it in an ultra-low temperature freezer at -70°C to -80°C for 4-5 hours. Then, under a vacuum of 10-30 Pa, the temperature is increased from -70°C to -80°C to -20°C to -10°C at a rate of 0.5-1°C / hour, and drying continues at this temperature for 4-6 hours. Afterward, under a vacuum of 1-10 Pa, the temperature is increased from -20°C to -10°C to 25-30°C at a rate of 1-2°C / hour, and drying continues at this temperature for 4-6 hours.

10. A high-energy-density metal sulfide cathode new energy material prepared by a method for preparing high-energy-density metal sulfide cathode new energy material as described in any one of claims 1-9.