A pyrite-based transition metal-doped energy storage material, its preparation method and application

Abstract

This invention discloses a pyrite-based transition metal-doped energy storage material, its preparation method, and its applications. The energy storage material is prepared by ultrasonic high-speed shearing of pyrite suspension A with an oxidant and a transition metal salt to obtain suspension B, which is then filtered, dried, and sintered with a carbon source to obtain the final product. Based on the high theoretical specific capacity of pyrite, this energy storage material significantly improves the energy band gap of pyrite through transition metal doping modification, effectively reducing material defects, thereby promoting electron transport and increasing interfacial electron conversion efficiency. Supercapacitors or secondary batteries prepared using the energy storage material provided by this invention have advantages such as high specific capacity, high rate capability, no volume effect, and good stability. Testing shows that lithium-ion batteries prepared using the material provided by this invention have a specific capacity of approximately 1200 mA g after 100 cycles. ‑1 The specific capacity of the sodium-ion battery after 100 cycles is consistently around 700 mA g. ‑1 above.

Description

Technical Field

[0001] This invention relates to a metal-doped energy storage material, specifically to a pyrite-based transition metal-doped energy storage material, its preparation method, and its application, belonging to the field of energy storage material development technology. Background Technology

[0002] Pyrite is the most widely distributed sulfide mineral in the Earth's crust. Its main component, FeS2, is an ideal alternative for secondary battery electrode materials, possessing excellent properties such as high specific capacity (theoretical specific capacity of 890 mAh / g), abundant resources, non-toxicity and environmental friendliness (both Fe and S are non-toxic), and a wide voltage plateau, making it a current research hotspot. At the same time, pyrite has unique magnetic and photoelectric properties, making it one of the promising materials for energy storage applications. Currently, some researchers have used natural pyrite directly as a secondary battery electrode material. However, during battery cycling, its poor conductivity, excessive volume expansion, and the shuttle effect of soluble polysulfides limit its application.

[0003] Therefore, it is of great significance to develop a pyrite-based battery material with high capacity, good cycle performance, and simple preparation method. Summary of the Invention

[0004] To address the problems existing in the prior art, the first objective of this invention is to provide a pyrite-based transition metal-doped energy storage material. This energy storage material is based on the high theoretical specific capacity of pyrite. Through transition metal doping modification, the energy band gap of pyrite is significantly improved, material defects are effectively reduced, thereby promoting electron transport and increasing the interface electron conversion efficiency.

[0005] The second objective of this invention is to provide a method for preparing pyrite-based transition metal doped energy storage materials. This method is based on the synergistic effect between the components. Through ultrasonic high-speed shearing force, pyrite, oxidant, and doped metal are simultaneously dissolved and reacted. The pyrite matrix has abundant heterogeneous doping defects, providing abundant doping sites for the transition metal. By adjusting the ratio of the three components, parameters such as the specific capacity and rate performance of the material can be directionally adjusted, thereby obtaining an energy storage material with excellent comprehensive performance.

[0006] The third objective of this invention is to provide an application of a pyrite-based transition metal-doped energy storage material for preparing a secondary battery anode material. The energy storage material provided by this invention has advantages such as high specific capacity, high rate capability, no volume effect, and good stability. The secondary battery anode prepared based on the energy storage material provided by this invention, after testing, showed that the specific capacity of the resulting lithium-ion battery after 100 cycles was consistently around 1200 mA g. -1 The specific capacity of the sodium-ion batteries obtained above after 100 cycles is consistently around 700 mA g. -1 above.

[0007] To achieve the above-mentioned technical objectives, this invention provides a method for preparing a pyrite-based transition metal doped energy storage material. Pyrite powder is added to water to obtain suspension A; an oxidant and a soluble metal salt are added to suspension A and mixed evenly, followed by ultrasonic high-speed shearing to obtain suspension B; suspension B is filtered, dried, mixed with a carbon source, and calcined to obtain the final product. The mass ratio of pyrite to water is 1:1 to 50; the mass percentage concentration of the oxidant in suspension B is 0.05% to 2%; the molar concentration of the soluble metal salt in suspension B is 0.2 to 2 mol / L; the soluble metal salt is at least one selected from soluble cobalt salt, soluble nickel salt, soluble zinc salt, and soluble copper salt.

[0008] As a preferred embodiment, the pyrite powder is natural pyrite or high-purity pyrite concentrate with a purity ≥90%.

[0009] As a preferred embodiment, the pyrite has a particle size of 1 to 100 micrometers.

[0010] As a preferred embodiment, the mass ratio of pyrite to water is 1:4 to 29. More preferably, the mass ratio of pyrite to water is 1:9 to 19.

[0011] As a preferred embodiment, the pyrite has a purity of ≥95% and a particle size of 1–50 micrometers. More preferably, the pyrite has a particle size of 1–20 μm.

[0012] As a preferred embodiment, the high-speed ultrasonic shearing is performed using an ultrasonic homogenizer, with the following conditions: rotation speed of 5000–6500 r / min and time of 1–8 h. More preferably, the ultrasonic homogenizer conditions are: 6000 r / min and time of 2–6 h.

[0013] As a preferred embodiment, the oxidant is at least one selected from hydrogen peroxide, perchloric acid, hypochlorous acid, sodium hypochlorite, ozone, and potassium permanganate.

[0014] As a preferred embodiment, the soluble metal salt is at least one of cobalt chloride, nickel sulfate, zinc chloride, and copper sulfate.

[0015] As a preferred embodiment, the oxidant has a mass percentage concentration of 0.1% to 1% in suspension B.

[0016] As a preferred embodiment, the soluble metal salt has a molar concentration of 0.5–1 mol / L in suspension B.

[0017] As a preferred embodiment, the carbon source is at least one of the following polymers: polyacrylamide, polyvinylpyrrolidone, polyurethane, polystyrene, polyethylene, polyolefin resin, and phenolic resin. The carbon source selected in this invention is an encapsulating polymeric carbon source. This is intended, on the one hand, to utilize the excellent encapsulation properties of the carbon source to form an integrated precursor, thereby ensuring that the calcined product has a uniform carbon encapsulation layer; on the other hand, because the intermediate and product particles in the preparation process of this invention are relatively large, the polymeric carbon source can prevent insufficient adsorption force leading to detachment during calcination. If a two-dimensional carbon source, such as graphite, graphene, or graphene oxide, is used, this cannot be guaranteed, resulting in carbon layer anisotropy and detachment problems.

[0018] As a preferred embodiment, in the pyrite-based energy storage material, the mass ratio of pyrite to carbon source is 1:1 to 10. More preferably, in the pyrite-based energy storage material, the mass ratio of pyrite to carbon source is 1:1 to 5.

[0019] As a preferred embodiment, the calcination temperature is 550–900℃, and the calcination time is 1–5 hours. More preferably, the calcination temperature is 600–750℃, and the calcination time is 2–3 hours.

[0020] The present invention also provides a pyrite-based transition metal doped energy storage material, which is prepared by any of the preparation methods described above.

[0021] This invention also provides an application of pyrite-based transition metal-doped energy storage materials for preparing secondary battery anode materials.

[0022] Compared with the prior art, the beneficial technical effects of the technical solution of the present invention are as follows:

[0023] 1) The pyrite-based transition metal doped energy storage material provided by the present invention is based on the high theoretical specific capacity of pyrite. Through transition metal doping modification, the energy band gap of pyrite is greatly improved, material defects are effectively reduced, thereby promoting electron transport and increasing the interface electron conversion efficiency.

[0024] 2) The preparation method provided by the present invention is based on the synergistic effect between the components. Through ultrasonic high-speed shearing force, pyrite-oxidant-doped metal are simultaneously dissolved and reacted. The pyrite matrix has abundant heterogeneous doping defects, which provide abundant doping sites for transition metals. By adjusting the ratio of the three components, the specific capacity, rate performance and other parameters of the material can be directionally adjusted, thereby obtaining an energy storage material with excellent comprehensive performance.

[0025] 3) The energy storage material provided by this invention has advantages such as high specific capacity, high rate capability, no volume effect, and good stability. The secondary battery anode prepared based on the energy storage material provided by this invention, after testing, showed that the specific capacity of the resulting lithium-ion battery after 100 cycles was consistently around 1200 mA g. -1 The specific capacity of the sodium-ion batteries obtained above after 100 cycles is consistently around 700 mA g. -1 above. Detailed Implementation

[0026] Example 1

[0027] Pyrite suspension A was prepared by mixing 10g of 98% pure natural pyrite concentrate with pure water at a mass ratio of 1:10. Hydrogen peroxide and nickel sulfate were added sequentially to the suspension, and the mixture was stirred thoroughly to dissolve. The solution was then subjected to high-speed ultrasonic shearing in an ultrasonic homogenizer at 6000 rpm for 4 hours, resulting in suspension B with a hydrogen peroxide mass percentage concentration of 0.5% and a nickel sulfate molar concentration of 0.5 mol / L. Suspension B was filtered, and the filtered product was dried at 70°C for 24 hours to obtain pyrite powder with adsorbed nickel ions. Polyacrylamide was added to the powder at a mass ratio of 1:3 (pyrite to polyacrylamide), and the mixture was thoroughly mixed and ground for 30 minutes. The mixture was then calcined in a tube furnace at 650°C for 3 hours, yielding a pyrite-based high-performance battery material. When used as a lithium-ion battery anode material, it exhibits high performance at a current density of 100 mA g / g. -1 After 100 cycles, a capacity of 1239 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, an 885mAh capacity can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mA g -1 After 100 cycles, a capacity of 728mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, a capacity of 560mAh can be obtained. -1 Specific capacity.

[0028] Example 2

[0029] A pyrite suspension was prepared by mixing 10g of 98% pure natural pyrite concentrate with 15μm particle size with pure water at a mass ratio of 1:15. Hypochlorous acid and cobalt chloride were added sequentially to suspension A, and the mixture was stirred thoroughly to dissolve. The solution was then subjected to high-speed ultrasonic shearing in an ultrasonic homogenizer at 6000 rpm for 4 hours, resulting in suspension B with a hypochlorous acid mass percentage concentration of 0.5% and a cobalt chloride molar concentration of 1 mol / L. Suspension B was filtered, and the filtered product was dried at 70℃ for 24 hours to obtain pyrite powder with cobalt ions adsorbed on its surface. Polystyrene was added to the powder at a mass ratio of pyrite to polystyrene of 1:3, and the mixture was thoroughly mixed and ground for 30 minutes. The mixture was then calcined in a tube furnace at 650℃ for 3 hours, yielding a pyrite-based high-performance battery material. When used as a lithium-ion battery anode material, it exhibits high performance at a current density of 100 mA g / g. -1 After 100 cycles, a capacity of 1264 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, a capacity of 906 mAh can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mA g -1 After 100 cycles, a capacity of 746 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, a capacity of 575mAh g can be obtained. -1 Specific capacity.

[0030] Example 3

[0031] Pyrite suspension A was prepared by mixing 10g of 98% pure natural pyrite concentrate with pure water at a mass ratio of 1:10. Perchloric acid and zinc chloride were added sequentially to suspension A, and the mixture was stirred thoroughly to dissolve. The solution was then subjected to high-speed ultrasonic shearing in an ultrasonic homogenizer at 6000 rpm for 4 hours, resulting in suspension B with a perchloric acid mass percentage concentration of 0.5% and a zinc chloride molar concentration of 0.5 mol / L. Suspension B was filtered, and the filtered product was dried at 70°C for 24 hours to obtain pyrite powder with zinc ion adsorbed on its surface. Polyethylene was added to the powder at a mass ratio of pyrite to polyethylene of 1:4, and the mixture was thoroughly mixed and ground for 30 minutes. The mixture was then calcined in a tube furnace at 650°C for 3 hours, yielding a pyrite-based high-performance battery material. When used as a negative electrode material for lithium-ion batteries, it exhibits high performance at a current density of 100 mA g / g. -1 After 100 cycles, a capacity of 1224 mAh g can be obtained. -1The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, 878mAh g can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mAg... -1 After 100 cycles, a capacity of 722mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, a capacity of 554 mAh g can be obtained. -1 Specific capacity.

[0032] Example 4

[0033] Pyrite suspension A was prepared by mixing 10g of 98% pure natural pyrite concentrate with pure water at a mass ratio of 1:15. Sodium hypochlorite and copper sulfate were added sequentially to suspension A, and the mixture was stirred thoroughly to dissolve. The solution was then subjected to high-speed ultrasonic shearing in an ultrasonic homogenizer at 6000 rpm for 4 hours, resulting in suspension B with a sodium hypochlorite mass percentage concentration of 1% and a copper sulfate molar concentration of 1 mol / L. Suspension B was filtered, and the filtered product was dried at 70°C for 24 hours to obtain pyrite powder with copper ions adsorbed on its surface. Phenolic resin was added to the powder at a mass ratio of pyrite to phenolic resin of 1:3, and the mixture was thoroughly mixed and ground for 30 minutes. The mixture was then calcined in a tube furnace at 650°C for 3 hours, yielding the pyrite-based high-performance battery material. When used as a lithium-ion battery anode material, it exhibits high performance at a current density of 100 mA g / g. -1 After 100 cycles, a capacity of 1315 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, a capacity of 924 mAh g can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mA g -1 After 100 cycles, a capacity of 786 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, a capacity of 604 mAh g can be obtained. -1 Specific capacity.

[0034] Comparative Example 1

[0035] The preparation process in Example 1 was performed in the same manner as in Example 1, except that hydrogen peroxide was not added. The resulting material, when used as a negative electrode material for lithium-ion batteries, exhibited performance at a current density of 100 mA g / g. -1 After 100 cycles, a capacity of 915mAh g can be obtained.-1 The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, 611mAh g can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mA g -1 After 100 cycles, a capacity of 554 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, a capacity of 356 mAh g can be obtained. -1 Specific capacity.

[0036] Comparative Example 2

[0037] The preparation process in Example 1 was performed in the same manner as in Example 1, except that nickel sulfate was not added. The resulting material, when used as a negative electrode material for lithium-ion batteries, exhibited performance at a current density of 100 mA g / g. -1 After 100 cycles, 856mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, a capacity of 398mAh g can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mA g -1 After 100 cycles, a capacity of 508mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, a capacity of 250mAh can be obtained. -1 Specific capacity.

[0038] Comparative Example 3

[0039] The preparation process in Example 1 was performed in the same manner as in Example 1, except that polyacrylamide was not added. The resulting material, when used as a negative electrode material for lithium-ion batteries, exhibited performance at a current density of 100 mA g / g. -1 After 100 cycles, 664 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, a capacity of 134 mAh g can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mA g -1 After 100 cycles, a capacity of 286 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, 72mAh g can be obtained. -1 Specific capacity.

[0040] Comparative Example 4

[0041] The preparation process in Example 1 was performed according to the steps of Example 1, except that the mass percentage concentration of hydrogen peroxide was changed to 0.02%. The resulting material, when used as a negative electrode material for lithium-ion batteries, exhibited performance at a current density of 100 mA g / g. -1 After 100 cycles, 875mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, 552 mAh g can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mAg... -1 After 100 cycles, a capacity of 598mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, a capacity of 384 mAh g can be obtained. -1 Specific capacity.

[0042] Comparative Example 5

[0043] The preparation process in Example 1 was performed according to the steps of Example 1, except that the concentration of nickel sulfate was changed to 0.1 mol / L. The resulting material, when used as a negative electrode material for lithium-ion batteries, exhibited performance at a current density of 100 mA g / g. -1 After 100 cycles, a capacity of 924 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 1000 cycles, a capacity of 588mAh can be obtained. -1 The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mAg... -1 After 100 cycles, a capacity of 612 mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mAg -1 After 500 cycles, a capacity of 396 mAh g can be obtained. -1 Specific capacity.

[0044] Comparative Example 6

[0045] The preparation process in Example 1 was performed according to the steps of Example 1, except that the mass ratio of pyrite to polyacrylamide was changed to 1:20. The resulting material, when used as a negative electrode material for lithium-ion batteries, exhibited performance at a current density of 100 mAg. -1 After 100 cycles, 806mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mAg -1 After 1000 cycles, a capacity of 674 mAh g can be obtained. -1The specific capacity. When used as a negative electrode material in sodium-ion batteries, at a current density of 100 mA g -1 After 100 cycles, a capacity of 595mAh g can be obtained. -1 The specific capacitance at a current density of 1500 mA g -1 After 500 cycles, a capacity of 387mAh g can be obtained. -1 Specific capacity.

Claims

1. A method for preparing a pyrite-based transition metal doped energy storage material, comprising: adding pyrite powder to water to obtain suspension A; adding an oxidant and a soluble metal salt to suspension A and mixing them evenly, followed by ultrasonic high-speed shearing to obtain suspension B; filtering and drying suspension B, then mixing it with a carbon source and calcining it to obtain the final product; wherein the mass ratio of pyrite to water is 1:1~50; the mass percentage concentration of the oxidant in suspension B is 0.05%~2%; the molar concentration of the soluble metal salt in suspension B is 0.2~2 mol / L; and the soluble metal salt is at least one selected from soluble cobalt salt, soluble nickel salt, soluble zinc salt, and soluble copper salt.

2. The method for preparing a pyrite-based transition metal doped energy storage material according to claim 1, wherein the pyrite powder is natural pyrite or high-purity pyrite concentrate with a purity ≥90%; and the particle size of the pyrite is 1~100 micrometers.

3. The method for preparing a pyrite-based transition metal doped energy storage material according to claim 1, wherein the mass ratio of pyrite to water is 1:4~29; the purity of the pyrite is ≥95%, and the particle size is 1~50 micrometers.

4. The method for preparing a pyrite-based transition metal doped energy storage material according to claim 1, wherein the process comprises: the ultrasonic high-speed shearing is performed by an ultrasonic homogenizer, and the conditions are: rotation speed of 5000~6500 r / min, time of 1~8 h.

5. The method for preparing a pyrite-based transition metal doped energy storage material according to claim 1, wherein the oxidant is at least one of hydrogen peroxide, perchloric acid, hypochlorous acid, sodium hypochlorite, ozone, and potassium permanganate; and the soluble metal salt is at least one of cobalt chloride, nickel sulfate, zinc chloride, and copper sulfate.

6. The method for preparing a pyrite-based transition metal doped energy storage material according to claim 1, wherein the oxidant has a mass percentage concentration of 0.1% to 1% in suspension B; and the soluble metal salt has a molar concentration of 0.5 to 1 mol / L in suspension B.

7. The method for preparing a pyrite-based transition metal doped energy storage material according to claim 1, wherein the carbon source is at least one of polyacrylamide, polyvinylpyrrolidone, polyurethane, polystyrene, polyethylene, polyolefin resin and phenolic resin; and the mass ratio of pyrite to carbon source in the energy storage material is 1:1 to 10.

8. The method for preparing a pyrite-based transition metal doped energy storage material according to claim 1, wherein the calcination temperature is 550~900℃ and the calcination time is 1~5h.