Preparation method of TiSi2N4 / TiN carbon composite material with heterogeneous structure

Abstract

The present invention relates to a preparation method of a TiSi2N4 / TiN carbon composite material with a heterogeneous structure, characterized in that the method comprises the following steps: taking 10 50g TiO2 powder, 1 5g carbon nanotubes and 1 5g triamino-s-triazine and mechanically mixing them in a high-energy ball mill, placing the obtained precursor in a tubular furnace for nitriding treatment, mechanically grinding in a high-energy ball mill after naturally cooling, adding 1 10g nano-silicon and 1 5g graphite phase carbon nitride and mechanically mixing them in a high-energy ball mill, sealing the obtained material with a vacuum quartz tube, and putting it into a muffle furnace for sintering treatment, mechanically grinding in a high-energy ball mill after naturally cooling, and obtaining a TiSi2N4 / TiN carbon composite material with a heterogeneous structure. The advantage of the method is that the obtained TiSi2N4 / TiN carbon composite material has good electronic conductivity and structural stability, so that the composite material has a long life and high capacity sodium storage characteristics.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon composite material preparation methods, and in particular to a preparation method of a TiSi2N4 / TiN carbon composite material with a heterogeneous structure. Background Art

[0002] Lithium-ion batteries are one of the most important energy storage and conversion technologies in today's society, widely used in portable electronic devices, power tools, electric vehicles, and drones. In recent years, as the lithium-ion battery market has expanded, the supply and demand of lithium resources has become increasingly tight, resulting in rising lithium salt prices, which in turn restricts the future development of lithium-ion batteries. Therefore, it is necessary to develop new sustainable energy storage and conversion devices. In contrast, sodium resources are extremely abundant in the Earth's crust and oceans, and their extraction technology is very mature, which means that the development of sodium-ion batteries has the advantages of abundant raw materials and low cost.

[0003] Currently, the market for sodium-ion batteries is mainly concentrated in areas such as low-speed electric vehicles and energy storage power stations, which requires sodium-ion batteries to have the characteristics of high capacity, high power, long life and low price. However, the current mainstream electrode materials for sodium-ion batteries (such as polyanion phosphates, Prussian blue and its derivatives, etc.) cannot meet these basic characteristics, so it is necessary to develop new host materials. Layered nitrides are a type of material with stable chemical properties, high electronic conductivity, corrosion resistance, and high temperature resistance. As a host material for sodium-ion batteries, they have the characteristics of high theoretical capacity, stable structure, and good safety. They fully meet the basic requirements for batteries used in low-speed electric vehicles and energy storage power stations, and have the potential value for large-scale development and use in the future. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that existing sodium ion batteries cannot meet the characteristics of high capacity, high power, long life and low price.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure, comprising the following steps:

[0006] 10-50g TiO2 powder, 1-5g carbon nanotubes and 1-5g triamino-s-triazine are mechanically mixed in a high-energy ball mill at 400-800r / min for 5h; the obtained precursor is placed in a tube furnace and nitrided under a 10-100ml / min ammonia gas flow at a heating rate of 2-5℃ / min and treated at 500-800℃ for 0.5-10h; after natural cooling, it is mechanically ground in a high-energy ball mill at 200-500r / min for 1h, and then 1-10g nano-silicon and 1-5g graphite phase carbon nitride are added in a high-energy ball mill. The mixture was mechanically mixed in a ball mill at 600-900 r / min for 5 hours; the obtained material was sealed with a vacuum quartz tube and placed in a muffle furnace for sintering treatment, firstly raised to 500-800°C at a heating rate of 2-5°C / min, kept constant at this temperature for 1-5 hours, then raised to 900-1200°C at a heating rate of 2-5°C / min, kept constant at this temperature for 2-10 hours; after natural cooling, the mixture was mechanically ground in a high-energy ball mill at 200-500 r / min for 1 hour, and the obtained sample was a TiSi2N4 / TiN carbon composite material with a heterogeneous structure.

[0007] Compared with the existing technology, the advantages of the present invention are: TiO2 and carbon nanotubes are used as raw materials to first construct a TiN / topological defect carbon composite material through an ammonia method, and then an appropriate amount of nano-silicon and carbon nitride are introduced to carry out mechanical thermal compounding with TiN / topological defect carbon, thereby obtaining a TiSi2N4 / TiN carbon composite material with a heterogeneous structure, and the obtained TiSi2N4 / TiN carbon composite material has a uniform particle size distribution and high electronic conductivity, which can effectively improve the sodium storage performance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a morphology diagram of the TiSi2N4 / TiN carbon composite material with a heterogeneous structure obtained in the present invention. DETAILED DESCRIPTION

[0009] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0010] A method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure comprises the following steps: first, 10-50g of TiO2 powder, 1-5g of carbon nanotubes and 1-5g of triamino-s-triazine are mechanically mixed in a high-energy ball mill at 400-800 rpm for 5 hours.

[0011] The TiO2 powder is brookite powder with a particle size of 5-9nm. Brookite is another isomorphous mineral of titanium dioxide, with a chemical composition of TiO2 and a titanium content of 59.95%. It has an orthorhombic crystal system and forms a three-dimensional isomorph with rutile and anatase.

[0012] At the same time, the carbon nanotubes are amino-modified multi-walled carbon nanotubes with a diameter of 10-50nm. The amino-modified multi-walled carbon nanotubes are started with carboxylated carbon nanotubes, and the carboxyl groups are converted into amide groups through an amidation reaction, and then decarbonylated at high temperature to obtain them.

[0013] Secondly, triamino-s-triazine is 2,4,6-triamino-s-triazine, also known as melamine, which is a triazine nitrogen-containing heterocyclic organic compound and is used as a chemical raw material.

[0014] The resulting precursor is then placed in a tube furnace and nitrided under a 10-100 ml / min ammonia flow at a heating rate of 2-5°C / min, and treated at 500-800°C for 0.5-10 hours. The precursor is the form of matter that exists before the target product is obtained, and most of the time it exists as a solid organic-inorganic complex or mixture, but some also exist as a sol.

[0015] After natural cooling, the mixture is mechanically ground in a high-energy ball mill at 200-500 r / min for 1 h, and then 1-10 g of nano-silicon and 1-5 g of graphite phase carbon nitride are added and mechanically mixed in a high-energy ball mill at 600-900 r / min for 5 h.

[0016] The particle size of nano-silicon is 10-25nm, and the graphite phase carbon nitride is g-C3N4 with a thickness of 1-2nm. g-C3N4 is a typical polymer semiconductor, and the CN atoms in its structure form a highly delocalized π conjugated system through sp2 hybridization.

[0017] The resulting material was sealed in a vacuum quartz tube and sintered in a muffle furnace. The temperature was first raised to 500-800°C at a rate of 2-5°C / min, held constant for 1-5 hours, and then raised to 900-1200°C at a rate of 2-5°C / min, held constant for 2-10 hours. After cooling naturally, the material was mechanically ground in a high-energy ball mill at 200-500 rpm for 1 hour. The resulting sample was a TiSi2N4 / TiN carbon composite with a heterogeneous structure. The specific structure of the sample was a nitrogen-doped carbon-encapsulated TiSi2N4 / TiN heterostructure dispersed within nitrogen-doped nanocarbon with topological defects. Topological defects refer to chemical bonds in certain regions of the crystal that differ from their surroundings in terms of topological shape and environment.

[0018] Therefore, the TiSi2N4 / TiN carbon composite material prepared by the present invention has a stable structure, uniform particle size distribution, and high electronic conductivity. At the same time, during the synthesis process, carbon nanotubes are a reducing agent and a three-dimensional conductive network, triamino-s-triazine is a solid-phase nitrogen source and a carbon layer coating agent, ammonia is a gaseous nitrogen source, and graphite-phase carbon nitride is a nitrogen source supplement and a carbon layer coating agent. Therefore, the specific structure of the obtained TiSi2N4 / TiN carbon composite material is a nitrogen-doped carbon-coated TiSi2N4 / TiN heterostructure dispersed in nitrogen-doped nanocarbon with topological defects. Moreover, in the composite material, the layered nitride itself has good electronic conductivity and chemical stability, nitrogen doping further improves the electronic conductivity of the composite material, topological defects enhance the affinity for sodium ions, the heterostructure increases the transmission speed of sodium ions and improves the structural stability of the host material, and the carbon coating maintains the long-cycle stability of the heterostructure, thereby ensuring that the prepared material has excellent sodium ion storage performance.

[0019] The values described above are all ranges. The following description uses a value within the range for illustration.

[0020] Example 1:

[0021] 10g TiO2 powder, 1g carbon nanotubes and 1g triamino-s-triazine were mechanically mixed in a high-energy ball mill at 400r / min for 5h; the obtained precursor was placed in a tube furnace and nitrided under a 10ml / min ammonia gas flow, with a heating rate of 2℃ / min and treated at 500℃ for 0.5h; after natural cooling, it was mechanically ground in a high-energy ball mill at 200r / min for 1h, and then 1g nano-silicon and 1g graphite phase carbon nitride were added in the high-energy ball mill. The mixture was mechanically mixed at 600 r / min in a machine for 5 hours; the obtained material was sealed with a vacuum quartz tube and placed in a muffle furnace for sintering treatment, firstly heated to 500°C at a heating rate of 2°C / min, kept constant at this temperature for 1 hour, then heated to 900°C at a heating rate of 2°C / min, kept constant at this temperature for 2 hours; after natural cooling, the mixture was mechanically ground at 200 r / min in a high-energy ball mill for 1 hour, and the obtained sample was a TiSi2N4 / TiN carbon composite material with a heterogeneous structure.

[0022] The obtained product was used as the research electrode, carbon cloth as the counter electrode, AgCl / Ag as the reference electrode, and 1 mol / LNa2SO4 aqueous solution as the electrolyte to assemble a sodium ion battery. The battery was then charged and discharged at a rate of 0.2C in the potential range of 0.0-2.0V. The initial discharge capacity was 289mAh / g, the charge capacity was 283mAh / g, and the reversible capacity after 500 cycles was 275mAh / g, showing excellent electrochemical performance.

[0023] Example 2:

[0024] 50g TiO2 powder, 5g carbon nanotubes and 5g triamino-s-triazine were mechanically mixed in a high-energy ball mill at 800r / min for 5h; the obtained precursor was placed in a tube furnace and nitrided under a 100ml / min ammonia gas flow, with a heating rate of 5℃ / min and treated at 800℃ for 10h; after natural cooling, it was mechanically ground in a high-energy ball mill at 500r / min for 1h, and then 10g nano-silicon and 5g graphite phase carbon nitride were added in the high-energy ball mill. The mixture was mechanically mixed in a machine at 900 r / min for 5 hours; the obtained material was sealed with a vacuum quartz tube and placed in a muffle furnace for sintering treatment, firstly heated to 800°C at a heating rate of 5°C / min, kept constant at this temperature for 5 hours, then heated to 1200°C at a heating rate of 5°C / min, kept constant at this temperature for 10 hours; after natural cooling, the mixture was mechanically ground in a high-energy ball mill at 500 r / min for 1 hour, and the obtained sample was a TiSi2N4 / TiN carbon composite material with a heterogeneous structure.

[0025] The obtained product was used as the research electrode, carbon cloth as the counter electrode, AgCl / Ag as the reference electrode, and 1 mol / LNa2SO4 aqueous solution as the electrolyte to assemble a sodium ion battery. The battery was then charged and discharged at a rate of 0.2C in the potential range of 0.0-2.0V. The initial discharge capacity was 301mAh / g, the charge capacity was 294mAh / g, and the reversible capacity after 500 cycles was 288mAh / g, showing excellent electrochemical performance.

[0026] Example 3:

[0027] 10g TiO2 powder, 5g carbon nanotubes and 3g triamino-s-triazine were mechanically mixed in a high-energy ball mill at 600r / min for 5h; the obtained precursor was placed in a tube furnace and nitrided under a 100ml / min ammonia gas flow, with a heating rate of 3℃ / min and treated at 700℃ for 8h; after natural cooling, it was mechanically ground in a high-energy ball mill at 500r / min for 1h, and then 1g nano-silicon and 5g graphite phase carbon nitride were added in the high-energy ball mill. The obtained material was sealed with a vacuum quartz tube and placed in a muffle furnace for sintering treatment, firstly raised to 600°C at a heating rate of 3°C / min, kept constant at this temperature for 3 hours, then raised to 1000°C at a heating rate of 2°C / min, kept constant at this temperature for 10 hours; after natural cooling, it was mechanically ground in a high-energy ball mill at 400r / min for 1 hour, and the obtained sample was a TiSi2N4 / TiN carbon composite material with a heterogeneous structure.

[0028] The obtained product was used as the research electrode, carbon cloth as the counter electrode, AgCl / Ag as the reference electrode, and 1 mol / LNa2SO4 aqueous solution as the electrolyte to assemble a sodium ion battery. The battery was then charged and discharged at a rate of 0.2C in the potential range of 0.0-2.0V. The initial discharge capacity was 288mAh / g, the charge capacity was 285mAh / g, and the reversible capacity after 500 cycles was 280mAh / g, showing excellent electrochemical performance.

[0029] Example 4:

[0030] 35g TiO2 powder, 3g carbon nanotubes and 4g triamino-s-triazine were mechanically mixed in a high-energy ball mill at 700r / min for 5h; the obtained precursor was placed in a tube furnace and nitrided under a 50ml / min ammonia gas flow, with a heating rate of 4℃ / min and treated at 600℃ for 4h; after natural cooling, it was mechanically ground in a high-energy ball mill at 300r / min for 1h, and then 6g nano-silicon and 2g graphite phase carbon nitride were added in the high-energy ball mill. The obtained material was sealed with a vacuum quartz tube and placed in a muffle furnace for sintering treatment, firstly raised to 700°C at a heating rate of 4°C / min, kept constant at this temperature for 2 hours, then raised to 1100°C at a heating rate of 3°C / min, kept constant at this temperature for 5 hours; after natural cooling, it was mechanically ground in a high-energy ball mill at 300r / min for 1 hour, and the obtained sample was a TiSi2N4 / TiN carbon composite material with a heterogeneous structure.

[0031] The obtained product was used as the research electrode, carbon cloth as the counter electrode, AgCl / Ag as the reference electrode, and 1 mol / LNa2SO4 aqueous solution as the electrolyte to assemble a sodium ion battery. The battery was then charged and discharged at a rate of 0.2C in the potential range of 0.0-2.0V. The initial discharge capacity was 279mAh / g, the charge capacity was 270mAh / g, and the reversible capacity after 500 cycles was 262mAh / g, showing excellent electrochemical performance.

[0032] Example 5:

[0033] 20g TiO2 powder, 4g carbon nanotubes and 2g triamino-s-triazine were mechanically mixed in a high-energy ball mill at 500r / min for 5h; the obtained precursor was placed in a tube furnace and nitrided under a 30ml / min ammonia gas flow, with a heating rate of 2℃ / min and treated at 650℃ for 6h; after natural cooling, it was mechanically ground in a high-energy ball mill at 400r / min for 1h, and then 3g nano-silicon and 3g graphite phase carbon nitride were added in a high-energy ball mill. The obtained material was sealed with a vacuum quartz tube and placed in a muffle furnace for sintering treatment, firstly heated to 600°C at a heating rate of 2°C / min, kept at this temperature for 4 hours, then heated to 950°C at a heating rate of 4°C / min, kept at this temperature for 8 hours; after natural cooling, it was mechanically ground in a high-energy ball mill at 350r / min for 1 hour, and the obtained sample was a TiSi2N4 / TiN carbon composite material with a heterogeneous structure.

[0034] The obtained product was used as the research electrode, carbon cloth as the counter electrode, AgCl / Ag as the reference electrode, and 1 mol / L Na2SO4 aqueous solution as the electrolyte to assemble a sodium ion battery. The charge and discharge cycle was carried out at a rate of 0.2C in the potential range of 0.0-2.0V. The initial discharge capacity was 291mAh / g, the charge capacity was 287mAh / g, and the reversible capacity after 500 cycles was 282mAh / g, thus showing excellent electrochemical performance.

[0035] Example 6:

[0036] 45g TiO2 powder, 5g carbon nanotubes and 3g triamino-s-triazine were mechanically mixed in a high-energy ball mill at 550r / min for 5h; the obtained precursor was placed in a tube furnace and nitrided under a 70ml / min ammonia gas flow with a heating rate of 3℃ / min and treated at 750℃ for 5h; after natural cooling, it was mechanically ground in a high-energy ball mill at 350r / min for 1h, and then 8g nano-silicon and 4g graphite phase carbon nitride were added and the mixture was nitrided in a high-energy ball mill at 70ml / min. Mechanical mixing was carried out at 550r / min for 5h; the obtained material was sealed with a vacuum quartz tube and placed in a muffle furnace for sintering treatment, firstly raised to 500-800℃ at a heating rate of 3℃ / min, kept constant at this temperature for 3 hours, then raised to 1000℃ at a heating rate of 2℃ / min, kept constant at this temperature for 4 hours; after natural cooling, mechanical grinding was carried out in a high-energy ball mill at 400r / min for 1h, and the obtained sample was a TiSi2N4 / TiN carbon composite material with a heterogeneous structure.

[0037] The obtained product was used as the research electrode, carbon cloth as the counter electrode, AgCl / Ag as the reference electrode, and 1 mol / LNa2SO4 aqueous solution as the electrolyte to assemble a sodium ion battery. The charge and discharge cycle was carried out at a rate of 0.2C in the potential range of 0.0-2.0V. The initial discharge capacity was 309mAh / g, the charge capacity was 300mAh / g, and the reversible capacity after 500 cycles was 295mAh / g, thus showing excellent electrochemical performance.

[0038] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. At the same time, the present invention is not limited to the above embodiments. Therefore, the present invention is subject to various changes and improvements without departing from the principles and scope of the present invention. Such changes and improvements fall within the scope of the invention as claimed.

Claims

1. A method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure, characterized in that: The following steps are involved: 10-50g TiO2 powder, 1-5g carbon nanotubes and 1-5g triamino-s-triazine are mechanically mixed in a high-energy ball mill at 400-800r / min for 5h; the obtained precursor is placed in a tube furnace and nitrided under a 10-100ml / min ammonia gas flow at a heating rate of 2-5℃ / min and treated at 500-800℃ for 0.5-10h; after natural cooling, it is mechanically ground in a high-energy ball mill at 200-500r / min for 1h, and then 1-10g nano-silicon and 1-5g graphite phase carbon nitride are added in a high-energy ball mill. The mixture was mechanically mixed in a ball mill at 600-900 r / min for 5 hours; the obtained material was sealed with a vacuum quartz tube and placed in a muffle furnace for sintering treatment, firstly raised to 500-800°C at a heating rate of 2-5°C / min, kept constant at this temperature for 1-5 hours, then raised to 900-1200°C at a heating rate of 2-5°C / min, kept constant at this temperature for 2-10 hours; after natural cooling, the mixture was mechanically ground in a high-energy ball mill at 200-500 r / min for 1 hour, and the obtained sample was a TiSi2N4 / TiN carbon composite material with a heterogeneous structure.

2. The method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure according to claim 1, characterized in that: The specific structure of the TiSi2N4 / TiN carbon composite material is a nitrogen-doped carbon-coated TiSi2N4 / TiN heterostructure dispersed in nitrogen-doped nanocarbon with topological defects.

3. The method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure according to claim 1, characterized in that: The TiO2 powder is brookite powder with a particle size of 5-9 nm.

4. The method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure according to claim 1, characterized in that: The carbon nanotubes are amino-modified multi-walled carbon nanotubes with a diameter of 10-50 nm.

5. The method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure according to claim 1, characterized in that: The triamino-s-triazine is 2,4,6-triamino-s-triazine.

6. The method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure according to claim 1, characterized in that: The particle size of the nano-silicon is 10-25 nm.

7. The method for preparing a TiSi2N4 / TiN carbon composite material with a heterogeneous structure according to claim 1, characterized in that: The graphite phase carbon nitride is g-C3N4 and has a thickness of 1-2 nm.

Images