High-activity high-purity titanium boride powder for lithium ion battery energy storage and a preparation method thereof

Abstract

The application provides a high-activity high-purity titanium boride powder for lithium ion battery energy storage and a preparation method thereof, and belongs to the technical field of titanium boride powder preparation. Through the conversion of iron oxide / nitrogen-doped carbon quantum dots into iron-based catalytic phases dispersed in the interface at high temperature and the provision of a high-activity carbon source, the conversion of titanium dioxide into titanium boride is facilitated and the generation of titanium carbide and free carbon is inhibited; the polyhydric alcohol-boric acid ester prepolymer serves as a dispersant and a coating layer, improves the mixing uniformity of titanium dioxide, boron carbide and other particles and supplements the boron source, and is converted into amorphous carbon and boron oxide glass phases after heating, thereby providing a local reduction and mass transfer channel and limiting the grain growth and hard agglomeration of titanium boride through the glass phase coating; through the synergy of double carbon sources and double boron sources and the catalysis-glass phase environment, fine titanium boride powder with good dispersity is obtained at a low reaction temperature, which can be used as a conductive ceramic component in a lithium ion battery energy storage electrode and can be used for energy storage battery related electrode coating materials.

Description

Technical Field

[0001] This invention belongs to the field of titanium boride powder preparation technology, and relates to a high-activity and high-purity titanium boride powder for lithium-ion battery energy storage and its preparation method. The powder can also be used as a conductive ceramic component in lithium-ion battery energy storage electrodes, and can be used as a coating material for related electrodes of energy storage batteries. Background Technology

[0002] Titanium boride, as an ultrahard refractory metallic ceramic material, exhibits great application potential in cutting tools, wear-resistant coatings, armor protection, and high-temperature electrodes due to its high melting point, high hardness, excellent electrical conductivity, and chemical stability. Among its preparation methods, the carbothermic reduction method, using titanium oxide and boron carbide as the main raw materials, is one of the paths with the potential for large-scale industrial production due to its relatively low raw material cost and direct process route. However, this traditional technical route still has shortcomings. Specifically, in the field of lithium-ion battery energy storage, conductive ceramic powder can be used as a functional component in electrode composite materials or electrode coatings to improve the conductive contact and heat resistance of electrode materials. In the fields of machining and high-end equipment, titanium boride powder can serve as a base powder for tool ceramic materials or wear-resistant coating materials.

[0003] The formation of titanium boride requires a high thermodynamic driving force, which means that the traditional carbothermic reduction reaction usually needs to be carried out at a high temperature above 1400℃. However, this temperature is far above the sintering activation temperature of the grains, making the newly formed titanium boride prone to neck growth and solid-state sintering, forming hard agglomerates that are difficult to disperse.

[0004] Secondly, titanium oxide, boron carbide, and carbon are all solid phases, and their reactions depend on slow solid-solid diffusion. This inefficient mass transfer process often leads to incomplete reactions and is kinetically prone to generating thermodynamically stable byproducts, especially titanium carbide and residual free carbon. The presence of these impurity phases impairs the final properties of titanium boride materials, and their subsequent removal is complex and may introduce secondary pollution.

[0005] Furthermore, although boron carbide is a cost-effective industrial boron source, its low reactivity is one of the fundamental reasons for the aforementioned high-temperature requirements and incomplete reaction problems. To achieve the reaction at low temperatures, researchers have attempted to use highly reactive amorphous boron powders, but this drastically increases production costs, limiting the widespread application of the technology. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a highly active and high-purity titanium boride powder for lithium-ion battery energy storage and its preparation method, thereby obtaining fine, high-purity titanium boride powder suitable as a conductive ceramic component for lithium-ion battery energy storage electrodes. This application utilizes the transformation of iron oxide / nitrogen-doped carbon quantum dots into an iron-based catalytic phase dispersed at the interface between titanium dioxide and carbon at high temperatures, providing a highly active carbon source. The iron-based phase may promote the interfacial carbothermic reduction of titanium dioxide and improve the reaction contact between the titanium source, carbon source, and boron source. The locally boron-rich liquid phase environment formed by the boron oxide glass phase helps increase the probability of the boration reaction and weakens the tendency to form titanium carbide and excess free carbon. The polyol-boron ester prepolymer acts as a dispersant and coating layer in the precursor stage, improving the mixing uniformity of titanium dioxide, boron carbide, and other particles and supplementing the boron source. After heating, it transforms into amorphous carbon and the boron oxide glass phase, providing both local reduction and mass transfer channels, and limiting the growth and hard agglomeration of titanium boride grains through glass phase coating. By employing a metrological design of dual carbon and dual boron sources and synergistic catalytic-glass phase environment, fine titanium boride powder with good dispersion can be obtained at a lower reaction temperature. This powder can be used as a conductive ceramic component in lithium-ion battery energy storage electrodes and can also be used as an electrode coating material for energy storage batteries.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing highly active and high-purity titanium boride powder for lithium-ion battery energy storage, the method comprising:

[0009] S1: Citric acid, urea and ferric chloride are added to deionized water to obtain a mixture. The pH is adjusted with ammonia to obtain reaction solution A. The mixture is reacted, centrifuged, washed and dried to obtain iron oxide / nitrogen-doped carbon quantum dots. Boric acid and glycerol are mixed and heated under a nitrogen atmosphere and stirred to obtain polyol-boron ester prepolymer.

[0010] S2: Add titanium dioxide, boron carbide, carbon black and iron oxide / nitrogen-doped carbon quantum dots to ethanol to obtain a mixed suspension, add polyol-boron ester prepolymer and ultrasonically disperse to obtain precursor slurry, vacuum dry the precursor slurry, grind and sieve to obtain precursor composite powder.

[0011] S3: The precursor composite powder is placed in a graphite crucible and subjected to programmed carbothermic reduction under an argon atmosphere: the temperature is raised to the first temperature and held, then raised to the second temperature and held, and cooled to room temperature with the furnace to obtain crude titanium boride.

[0012] S4: Crude titanium boride is dispersed in hydrochloric acid solution to obtain an acid washing solution. The solution is stirred at room temperature and centrifuged to obtain a crude product. The product is washed with deionized water, then with hot deionized water, and finally with ethanol. After drying, high-activity and high-purity titanium boride powder for lithium-ion battery energy storage is obtained.

[0013] As a preferred technical solution of the present invention, in step S1, the molar ratio of citric acid to urea is 1:(3-8), for example, it can be 1:3.0, 1:3.5, 1:4.0, 1:4.5, 1:5.0, 1:5.5, 1:6.0, 1:6.5, 1:7.0, 1:7.5 or 1:8.0, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0014] In some alternative embodiments, the molar ratio of citric acid to ferric chloride is 1:(0.05-0.2), for example, it can be 1:0.050, 1:0.065, 1:0.080, 1:0.095, 1:0.110, 1:0.125, 1:0.140, 1:0.155, 1:0.170, 1:0.185 or 1:0.200, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0015] In some optional embodiments, the total mass ratio of citric acid, urea, and ferric chloride to the volume ratio of deionized water is 1g:(15-25)mL, for example, it can be 1g:15mL, 1g:16mL, 1g:17mL, 1g:18mL, 1g:19mL, 1g:20mL, 1g:21mL, 1g:22mL, 1g:23mL, 1g:24mL, or 1g:25mL, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0016] In some alternative embodiments, the concentration of the ammonia water is 1-2M, for example, it can be 1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M, 1.6M, 1.7M, 1.8M, 1.9M or 2.0M, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0017] In some alternative embodiments, the pH of the mixture is adjusted to 6-7 using ammonia, for example, to 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 or 7.0, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0018] In some optional embodiments, the reaction temperature of the reaction solution A is 180-200°C, for example, it can be 180°C, 182°C, 184°C, 186°C, 188°C, 190°C, 192°C, 194°C, 196°C, 198°C or 200°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0019] In some optional embodiments, the reaction time of the reaction solution A is 6-10 hours, for example, 6.0 hours, 6.4 hours, 6.8 hours, 7.2 hours, 7.6 hours, 8.0 hours, 8.4 hours, 8.8 hours, 9.2 hours, 9.6 hours, or 10.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0020] In some alternative embodiments, the molar ratio of boric acid to glycerol is 1:(1.5-2.5), for example, it can be 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4 or 1:2.5, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0021] In some optional embodiments, the temperature at which the boric acid and glycerol are mixed and heated is 130-160°C, for example, 130°C, 133°C, 136°C, 139°C, 142°C, 145°C, 148°C, 151°C, 154°C, 157°C or 160°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0022] In some optional embodiments, the reaction time after mixing boric acid and glycerol is 2-5 hours, for example, 2.0 hours, 2.3 hours, 2.6 hours, 2.9 hours, 3.2 hours, 3.5 hours, 3.8 hours, 4.1 hours, 4.4 hours, 4.7 hours or 5.0 hours, but not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0023] As a preferred technical solution of the present invention, in step S2, the molar ratio of titanium dioxide, boron carbide and carbon black is 2:1:(2.8-3.0), for example, it can be 2:1:2.80, 2:1:2.82, 2:1:2.84, 2:1:2.86, 2:1:2.88, 2:1:2.90, 2:1:2.92, 2:1:2.94, 2:1:2.96, 2:1:2.98 or 2:1:3.00, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] In some optional embodiments, the amount of iron oxide / nitrogen-doped carbon quantum dots fed is 5-10% of the mass of titanium dioxide, for example, it can be 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5% or 10.0%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0025] In some optional embodiments, the solid-liquid mass ratio of the mixed suspension is 1:(5-10), for example, it can be 1:5.0, 1:5.5, 1:6.0, 1:6.5, 1:7.0, 1:7.5, 1:8.0, 1:8.5, 1:9.0, 1:9.5 or 1:10.0, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0026] In some optional embodiments, the amount of the polyol-boron ester prepolymer fed is 15-25% of the mass of titanium dioxide, for example, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0027] In some optional embodiments, the vacuum drying temperature of the precursor slurry is 50-80°C, for example, 50°C, 53°C, 56°C, 59°C, 62°C, 65°C, 68°C, 71°C, 74°C, 77°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0028] In some optional embodiments, the vacuum drying time of the precursor slurry is 12-24 hours, for example, 12.0 hours, 13.2 hours, 14.4 hours, 15.6 hours, 16.8 hours, 18.0 hours, 19.2 hours, 20.4 hours, 21.6 hours, 22.8 hours, or 24.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0029] As a preferred technical solution of the present invention, in step S3, the heating rate is 5-10℃ / min, for example, it can be 5.0℃ / min, 5.5℃ / min, 6.0℃ / min, 6.5℃ / min, 7.0℃ / min, 7.5℃ / min, 8.0℃ / min, 8.5℃ / min, 9.0℃ / min, 9.5℃ / min or 10.0℃ / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] In some alternative embodiments, the first temperature is 550-650°C, for example, it can be 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C or 650°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0031] In some optional embodiments, the heat preservation time at the first temperature is 1-2 hours, for example, it can be 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2.0h, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0032] In some alternative embodiments, the second temperature is 1300-1400°C, for example, it can be 1300°C, 1310°C, 1320°C, 1330°C, 1340°C, 1350°C, 1360°C, 1370°C, 1380°C, 1390°C or 1400°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0033] In some optional embodiments, the heat preservation time at the second temperature is 2-4 hours, for example, it can be 2.0 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3.0 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0034] As a preferred technical solution of the present invention, in step S4, the concentration of the hydrochloric acid solution is 1-2M, for example, it can be 1.0M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M, 1.6M, 1.7M, 1.8M, 1.9M or 2.0M, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0035] In some optional embodiments, the mass-to-volume ratio of the crude titanium boride to the hydrochloric acid solution is 1 g:(20-30) mL, for example, it can be 1 g:20 mL, 1 g:21 mL, 1 g:22 mL, 1 g:23 mL, 1 g:24 mL, 1 g:25 mL, 1 g:26 mL, 1 g:27 mL, 1 g:28 mL, 1 g:29 mL or 1 g:30 mL, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0036] In some optional embodiments, the pickling solution is stirred at room temperature for 3-6 hours, for example, 3.0 hours, 3.3 hours, 3.6 hours, 3.9 hours, 4.2 hours, 4.5 hours, 4.8 hours, 5.1 hours, 5.4 hours, 5.7 hours or 6.0 hours, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0037] In some alternative embodiments, the crude product is washed with deionized water until the pH of the supernatant is 6-7, for example, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 or 7.0, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0038] In some optional embodiments, the temperature of the hot deionized water is 75-85°C, for example, it can be 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C or 85°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0039] In some optional embodiments, the hot deionized water washing is performed 3 to 5 times, for example, 3, 4 or 5 times, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Secondly, the present invention provides a highly active, high-purity titanium boride powder for lithium-ion battery energy storage. The highly active, high-purity titanium boride powder can be used as a conductive ceramic component in the lithium-ion battery energy storage electrode, or as a functional ceramic component in the electrode coating material of the energy storage battery. Furthermore, the highly active, high-purity titanium boride powder can also be used as a base powder for cutting tool materials or wear-resistant coating materials for machine tool equipment.

[0041] The iron oxide / nitrogen-doped carbon quantum dots introduced in this application simultaneously serve as a catalyst and a highly active carbon source. In the iron oxide / nitrogen-doped carbon quantum dots, the iron oxide is dispersed on a large scale within the nitrogen-doped carbon matrix, facilitating uniform distribution on the surfaces of titanium dioxide and boron carbide particles during precursor preparation. At high temperatures, the iron oxide further transforms into a highly catalytically active iron phase or carbon-containing iron phase. The iron phase, located at the interface between titanium dioxide and the carbon source, helps lower the energy barrier of the reduction process, facilitating the transformation of titanium dioxide into low-valence titanium species and then into titanium boride within a lower temperature range. The nitrogen-doped carbon quantum dots, as a carbon source with more structural defects, participate more readily in the reduction process than ordinary carbon black. By preferentially participating in gas generation and interfacial reactions, they synergistically regulate the reduction rate and the distribution of the reaction region in conjunction with the iron phase. With a carbon equivalent that meets or approaches the stoichiometric requirements and a sufficient supply of boron source, the selective catalytic effect of iron-based catalysts on the carbothermic reduction reaction of titanium dioxide is utilized to preferentially promote the conversion pathway of titanium dioxide to titanium boride. Furthermore, the boronization reaction pathway is enhanced in the locally boron-rich environment provided by the boron oxide glass phase, thereby reducing the possibility of the formation of titanium carbide and excess free carbon.

[0042] The nitrogen-doped carbon quantum dots gradually carbonize and graphitize at high temperatures, and their "quantum confinement" structural characteristics largely disappear in the main carbothermic reduction reaction temperature range. However, the morphological advantages of nitrogen-doped carbon quantum dots in precursor preparation and low-temperature pyrolysis stages remain irreplaceable: their nanoscale carbon matrix serves as a carrier for iron oxide nanoparticles, ensuring the uniform dispersion of the iron catalytic precursor on the surfaces of titanium dioxide and boron carbide particles, laying the structural foundation for the subsequent interfacial distribution of the iron-based catalytic phase. Furthermore, the nitrogen-doping sites remaining in the carbon quantum dot framework can introduce local defects into the carbon matrix during carbonization, allowing them to preferentially participate in partial reduction reactions at low temperatures, thus playing a role in assisting in regulating the initial reaction rate.

[0043] In this application, the polyol-boron ester prepolymer primarily functions as a dispersant and a structure-regulating precursor during the precursor preparation stage. The prepolymer, added in liquid form to the mixed suspension, uniformly wets titanium dioxide, boron carbide, carbon black, and iron oxide / nitrogen-doped carbon quantum dot particles under ultrasonic conditions, and solidifies into a coating layer during drying. In this coating structure, the solid particles are separated by an organic boron framework, reducing the agglomeration and segregation phenomena commonly found in simple dry mixing, thus providing a foundation for a more uniform reaction interface in the subsequent high-temperature stage. Simultaneously, the prepolymer itself introduces an additional boron source and a carbonizable organic framework, creating conditions for subsequent construction of a glassy phase environment and supplemental boron supply.

[0044] During the programmed temperature carbothermic reduction process, the polyol-boron ester prepolymer further transforms into amorphous carbon and a boron oxide glass phase dominated by boron oxide. The amorphous carbon is distributed along the original coating layer, providing a localized reduction environment for titanium dioxide and boron oxide. At high temperatures, the boron oxide forms a glass phase with a certain degree of fluidity, filling the spaces between particles or surrounding newly formed titanium boride grains. On one hand, this glass phase, as a temporarily existing liquid medium, facilitates the migration of oxygen, boron, and other species between particles, allowing some of the reduction and borination processes, which were originally limited by solid-solid contact, to proceed with the participation of the glass phase, thereby improving reactant contact efficiency and local reaction rate. On the other hand, the coating of the glass phase on the particle surface weakens the direct sintering necking between titanium boride grains, helping to limit grain growth and hard agglomeration. This makes it easier to dissociate the agglomerates into smaller, more dispersed powders during subsequent washing and dispersion. In the micro-regions formed by the pyrolysis of the prepolymer, amorphous carbon and boron oxide coexist, and at high temperatures, they may undergo limited reduction or migration of boron-containing intermediates. This reaction may consume some carbon and boron, but it helps to create a highly reactive boron-containing reaction environment locally. This environment allows the boron to migrate in the boron oxide liquid medium and participate in the borylation reaction of titanium dioxide, thus, to some extent, converting this side reaction into an effective boron supply pathway for the borylation reaction. By controlling the carbon / boron ratio of the prepolymer (adjusted by the molar ratio of boric acid to glycerol), this internal side reaction can be kept within a reasonable range, preventing it from significantly affecting the overall stoichiometric equilibrium of the reaction.

[0045] In the post-processing stage, acid washing and hot water washing are used to remove the iron-based phase and the boron oxide glassy phase, respectively. Acid washing mainly dissolves and removes residual iron, iron oxides, and some acid-soluble iron-containing phases, allowing the iron-based catalyst to separate from the final powder. Hot water washing gradually removes some of the residual boron oxide glassy phase through hydrolysis and dissolution, releasing the coated titanium boride particles. Ethanol washing and vacuum drying complete the desolvation and drying steps without introducing strong sintering driving forces, reducing secondary agglomeration.

[0046] In this application, there is a synergistic enhancement effect between iron oxide / nitrogen-doped carbon quantum dots and polyol-boron ester prepolymers. Iron oxide / nitrogen-doped carbon quantum dots provide well-dispersed catalytic centers and active carbon sources, enabling the main reaction to proceed at temperatures lower than conventional processes. The glassy phase generated by the pyrolysis of the polyol-boron ester prepolymer provides a three-dimensional liquid-phase environment for these catalytic centers, allowing catalysis to occur over a wider area, no longer limited to finite solid-solid contact points. Simultaneously, the dual carbon sources (carbon generated from the pyrolysis of carbon black and two additives) are quantified to ensure that the added carbon black is close to the theoretical requirement, while the carbon from the pyrolysis of the additives participates in the interfacial reaction as a local compensating carbon source, controlling the overall risk of excess carbon residue. The boron source is jointly provided by boron carbide and the polyol-boron ester prepolymer; the former ensures the stoichiometry of the main reaction, while the latter provides compensating boron supply in the glassy phase to reduce the probability of non-target phase formation due to local boron deficiency. The resulting fine, high-purity, and well-dispersed titanium boride powder is more convenient to be used as a conductive ceramic component in lithium-ion battery energy storage electrodes, and can also be used as a base powder for ceramic materials used in energy storage battery electrode coatings or machining equipment.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] This application utilizes iron oxide / nitrogen-doped carbon quantum dots to provide a catalytic center and a highly active carbon source: the iron oxide is transformed into an iron phase or a carbon-containing iron phase at high temperature at the titanium dioxide / carbon interface, which reduces the temperature and energy barrier of the conversion of titanium dioxide to titanium boride, and in the boron-rich liquid environment provided by the boron oxide glass phase, the borination reaction is kinetically preferential over the carbide reaction, thereby effectively suppressing the generation of titanium carbide and excess free carbon; nitrogen-doped carbon quantum dots, as a carbon source that is more likely to participate in the reaction, work together with the iron phase to regulate the reduction rate and reaction region.

[0049] This application utilizes polyol-boron ester prepolymer as a dispersant and coating layer in the precursor stage to improve the mixing uniformity of titanium dioxide, boron carbide and other particles and introduce an additional boron source. During the heating process, it is transformed into amorphous carbon and boron oxide glass phase, which on the one hand provides a local reduction environment and promotes material migration, and on the other hand, the glass phase coating inhibits the growth and hard agglomeration of titanium boride grains, which is conducive to obtaining fine titanium boride powder with better dispersibility. This is beneficial to its dispersion and interfacial contact in the electrode system when it is used as a conductive ceramic component of lithium-ion battery energy storage electrode.

[0050] This application utilizes the synergistic effect of iron oxide / nitrogen-doped carbon quantum dots and polyol-boron ester prepolymers. Iron oxide / nitrogen-doped carbon quantum dots provide dispersed catalytic centers and active carbon sources, while polyol-boron ester prepolymers form a glassy liquid environment to amplify catalytic and mass transfer effects. Simultaneously, through the metrological design of dual carbon and dual boron sources, the overall carbon and boron equivalents are made close to the theoretical requirements. This reduces the reaction temperature while suppressing the formation of secondary phases caused by excess carbon and local boron deficiency. As a result, the obtained titanium boride powder is more suitable as a base powder for lithium-ion battery energy storage materials, energy storage battery electrode coating materials, and ceramic materials for machining equipment. Attached Figure Description

[0051] Figure 1 Scanning electron microscope image of the high-activity, high-purity titanium boride powder for lithium-ion battery energy storage prepared in Example 1 of this application;

[0052] Figure 2 XRD pattern of the high-activity, high-purity titanium boride powder for lithium-ion battery energy storage prepared in Example 1 of this application. Detailed Implementation

[0053] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include any obvious substitutions and modifications made to the embodiments described herein.

[0054] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone further purification or processing.

[0055] Example 1

[0056] This embodiment provides a highly active, high-purity titanium boride powder for lithium-ion battery energy storage and its preparation method. The preparation method of the highly active, high-purity titanium boride powder for lithium-ion battery energy storage specifically includes the following steps:

[0057] S1: Citric acid, urea, and ferric chloride were added to deionized water to obtain a mixture, wherein the molar ratio of citric acid to urea was 1:7, the molar ratio of citric acid to ferric chloride was 1:0.18, and the total mass of citric acid, urea, and ferric chloride to the volume ratio of deionized water was 1 g:22 mL. The pH was adjusted to 6.8 with 1.8 M ammonia water to obtain reaction solution A. The mixture was reacted at 195 °C for 9 h, centrifuged, washed, and dried to obtain iron oxide / nitrogen-doped carbon quantum dots. Boric acid and glycerol were mixed at a molar ratio of 1:2.2 and heated to 155 °C under a nitrogen atmosphere and stirred for 4 h to obtain a polyol-boron ester prepolymer.

[0058] S2: Titanium dioxide, boron carbide, carbon black, and iron oxide / nitrogen-doped carbon quantum dots are added to ethanol to obtain a mixed suspension, wherein the molar ratio of titanium dioxide, boron carbide, and carbon black is 2:1:2.95, the amount of iron oxide / nitrogen-doped carbon quantum dots is 8% of the mass of titanium dioxide, and the solid-liquid mass ratio of the mixed suspension is 1:9. Polyol-boron ester prepolymer is added and ultrasonically dispersed to obtain a precursor slurry, wherein the amount of polyol-boron ester prepolymer is 22% of the mass of titanium dioxide. The precursor slurry is vacuum dried at 75°C for 20 hours, and then ground and sieved to obtain a precursor composite powder.

[0059] S3: The precursor composite powder was placed in a graphite crucible and subjected to programmed carbothermic reduction under an argon atmosphere: the temperature was increased to the first temperature of 620℃ at a heating rate of 8℃ / min and held for 1.8h, then increased to the second temperature of 1330℃ and held for 3.5h, and then cooled to room temperature with the furnace to obtain crude titanium boride.

[0060] S4: Crude titanium boride was dispersed in a 1.7M hydrochloric acid solution to obtain an acid washing solution, wherein the mass-to-volume ratio of crude titanium boride to hydrochloric acid solution was 1g:28mL. The solution was stirred at room temperature for 5h, centrifuged to obtain a crude product, washed with deionized water until the pH of the supernatant was 6.9, then washed four times with hot deionized water at 82℃, and finally washed with ethanol and dried to obtain high-activity, high-purity titanium boride powder for lithium-ion battery energy storage. Figure 1 The image shows a scanning electron microscope (SEM) image of the prepared powder. The powder is relatively uniformly distributed, with no obviously large particles or severely agglomerated areas observed. Figure 2 As shown, all XRD diffraction peaks of the powder correspond to the standard card for hexagonal titanium boride, and no obvious characteristic peaks of impurity phases such as titanium carbide, titanium dioxide, or boron carbide were observed, indicating that the sample is mainly composed of titanium boride and has high phase purity. This powder can be used as a conductive ceramic component in the energy storage electrode of lithium-ion batteries, or as a functional ceramic component in the electrode coating material of energy storage batteries.

[0061] Example 2

[0062] This embodiment provides a highly active, high-purity titanium boride powder for lithium-ion battery energy storage and its preparation method. The preparation method of the highly active, high-purity titanium boride powder for lithium-ion battery energy storage specifically includes the following steps:

[0063] S1: Citric acid, urea, and ferric chloride were added to deionized water to obtain a mixture, wherein the molar ratio of citric acid to urea was 1:3, the molar ratio of citric acid to ferric chloride was 1:0.05, and the total mass of citric acid, urea, and ferric chloride to the volume ratio of deionized water was 1g:15mL. The pH was adjusted to 6 with 1M ammonia water to obtain reaction solution A. The reaction was carried out at 180℃ for 6h, centrifuged, washed, and dried to obtain iron oxide / nitrogen-doped carbon quantum dots. Boric acid and glycerol were mixed at a molar ratio of 1:1.5 and heated to 130℃ under a nitrogen atmosphere and stirred for 2h to obtain polyol-boron ester prepolymer.

[0064] S2: Titanium dioxide, boron carbide, carbon black, and iron oxide / nitrogen-doped carbon quantum dots are added to ethanol to obtain a mixed suspension, wherein the molar ratio of titanium dioxide, boron carbide, and carbon black is 2:1:2.8, the amount of iron oxide / nitrogen-doped carbon quantum dots is 5% of the mass of titanium dioxide, and the solid-liquid mass ratio of the mixed suspension is 1:5. Polyol-boron ester prepolymer is added and ultrasonically dispersed to obtain a precursor slurry, wherein the amount of polyol-boron ester prepolymer is 15% of the mass of titanium dioxide. The precursor slurry is vacuum dried at 50°C for 12 hours, and then ground and sieved to obtain a precursor composite powder.

[0065] S3: The precursor composite powder is placed in a graphite crucible and subjected to programmed carbothermic reduction under an argon atmosphere: the temperature is increased to the first temperature of 550℃ at a heating rate of 5℃ / min and held for 1h, then increased to the second temperature of 1350℃ and held for 2h, and then cooled to room temperature with the furnace to obtain crude titanium boride.

[0066] S4: Crude titanium boride was dispersed in a 1M hydrochloric acid solution to obtain an acid washing solution, wherein the mass-volume ratio of crude titanium boride to hydrochloric acid solution was 1g:20mL. The solution was stirred at room temperature for 3 hours, centrifuged to obtain a crude product, washed with deionized water until the pH of the supernatant was 6, then washed three times with hot deionized water at 75℃, and finally washed with ethanol and dried to obtain high-activity, high-purity titanium boride powder for lithium-ion battery energy storage.

[0067] Example 3

[0068] This embodiment provides a highly active, high-purity titanium boride powder for lithium-ion battery energy storage and its preparation method. The preparation method of the highly active, high-purity titanium boride powder for lithium-ion battery energy storage specifically includes the following steps:

[0069] S1: Citric acid, urea, and ferric chloride were added to deionized water to obtain a mixture, wherein the molar ratio of citric acid to urea was 1:5, the molar ratio of citric acid to ferric chloride was 1:0.1, and the total mass of citric acid, urea, and ferric chloride to the volume ratio of deionized water was 1g:18mL. The pH was adjusted to 6.2 with 1.2M ammonia water to obtain reaction solution A. The mixture was reacted at 185℃ for 7h, centrifuged, washed, and dried to obtain iron oxide / nitrogen-doped carbon quantum dots. Boric acid and glycerol were mixed at a molar ratio of 1:1.8 and heated to 140℃ under a nitrogen atmosphere with stirring for 3h to obtain polyol-boron ester prepolymer.

[0070] S2: Titanium dioxide, boron carbide, carbon black, and iron oxide / nitrogen-doped carbon quantum dots are added to ethanol to obtain a mixed suspension, wherein the molar ratio of titanium dioxide, boron carbide, and carbon black is 2:1:2.85, the amount of iron oxide / nitrogen-doped carbon quantum dots is 7% of the mass of titanium dioxide, and the solid-liquid mass ratio of the mixed suspension is 1:6. Polyol-boron ester prepolymer is added and ultrasonically dispersed to obtain a precursor slurry, wherein the amount of polyol-boron ester prepolymer is 18% of the mass of titanium dioxide. The precursor slurry is vacuum dried at 60℃ for 16h, and then ground and sieved to obtain a precursor composite powder.

[0071] S3: The precursor composite powder was placed in a graphite crucible and subjected to programmed carbothermic reduction under an argon atmosphere: the temperature was increased to the first temperature of 580℃ at a heating rate of 7℃ / min and held for 1.2h, then increased to the second temperature of 1400℃ and held for 2.5h, and then cooled to room temperature with the furnace to obtain crude titanium boride.

[0072] S4: Crude titanium boride was dispersed in a 1.3M hydrochloric acid solution to obtain an acid washing solution, wherein the mass-to-volume ratio of crude titanium boride to hydrochloric acid solution was 1g:22mL. The solution was stirred at room temperature for 4 hours, centrifuged to obtain a crude product, washed with deionized water until the pH of the supernatant was 6.3, then washed four times with hot deionized water at 78℃, and finally washed with ethanol and dried to obtain high-activity, high-purity titanium boride powder for lithium-ion battery energy storage.

[0073] Example 4

[0074] This embodiment provides a highly active, high-purity titanium boride powder for lithium-ion battery energy storage and its preparation method. The preparation method of the highly active, high-purity titanium boride powder for lithium-ion battery energy storage specifically includes the following steps:

[0075] S1: Citric acid, urea, and ferric chloride were added to deionized water to obtain a mixture, wherein the molar ratio of citric acid to urea was 1:8, the molar ratio of citric acid to ferric chloride was 1:0.2, and the total mass of citric acid, urea, and ferric chloride to the volume ratio of deionized water was 1 g:25 mL. The pH was adjusted to 7 with 2M ammonia water to obtain reaction solution A. The mixture was reacted at 200℃ for 10 h, centrifuged, washed, and dried to obtain iron oxide / nitrogen-doped carbon quantum dots. Boric acid and glycerol were mixed at a molar ratio of 1:2.5 and heated to 160℃ under a nitrogen atmosphere with stirring for 5 h to obtain polyol-boron ester prepolymer.

[0076] S2: Titanium dioxide, boron carbide, carbon black, and iron oxide / nitrogen-doped carbon quantum dots are added to ethanol to obtain a mixed suspension, wherein the molar ratio of titanium dioxide, boron carbide, and carbon black is 2:1:3.0, the amount of iron oxide / nitrogen-doped carbon quantum dots is 10% of the mass of titanium dioxide, and the solid-liquid mass ratio of the mixed suspension is 1:10. Polyol-boron ester prepolymer is added and ultrasonically dispersed to obtain a precursor slurry, wherein the amount of polyol-boron ester prepolymer is 25% of the mass of titanium dioxide. The precursor slurry is vacuum dried at 80℃ for 24h, and then ground and sieved to obtain a precursor composite powder.

[0077] S3: The precursor composite powder is placed in a graphite crucible and subjected to programmed carbothermic reduction under an argon atmosphere: the temperature is increased to the first temperature of 650℃ at a heating rate of 10℃ / min and held for 2h, then increased to the second temperature of 1300℃ and held for 4h, and then cooled to room temperature with the furnace to obtain crude titanium boride.

[0078] S4: Crude titanium boride was dispersed in a 2M hydrochloric acid solution to obtain an acid washing solution, wherein the mass-volume ratio of crude titanium boride to hydrochloric acid solution was 1g:30mL. The solution was stirred at room temperature for 6 hours, centrifuged to obtain a crude product, washed with deionized water until the pH of the supernatant was 7, then washed 5 times with hot deionized water at 85℃, and finally washed with ethanol and dried to obtain high-activity, high-purity titanium boride powder for lithium-ion battery energy storage.

[0079] Comparative Example 1

[0080] This comparative example provides a highly active and high-purity titanium boride powder for lithium-ion battery energy storage. The difference from Example 1 is that no polyol-boron ester prepolymer is added, while the other operating steps and process parameters are exactly the same as in Example 1.

[0081] Comparative Example 2

[0082] This comparative example provides a highly active and high-purity titanium boride powder for lithium-ion battery energy storage. The difference from Example 1 is that no iron oxide / nitrogen-doped carbon quantum dots are added, while the other operating steps and process parameters are exactly the same as in Example 1.

[0083] Comparative Example 3

[0084] This comparative example provides a highly active and high-purity titanium boride powder for lithium-ion battery energy storage. The difference from Example 1 is that it does not contain iron oxide / nitrogen-doped carbon quantum dots and polyol-boron ester prepolymer. Other operating steps and process parameters are exactly the same as in Example 1.

[0085] The performance of the high-activity, high-purity titanium boride powder for lithium-ion battery energy storage in Examples 1-4 and Comparative Examples 1-3 was tested, and the specific process is as follows:

[0086] The purity of the prepared lithium-ion battery energy storage material was tested by XRD.

[0087] The particle size distribution of the high-activity, high-purity titanium boride powder for lithium-ion battery energy storage was tested using a laser particle size analyzer.

[0088] The high-activity, high-purity titanium boride powder for lithium-ion battery energy storage was hot-pressed and sintered under the same conditions, and the relative density of the sintered body was tested to verify the sintering activity of the powder.

[0089] The test results are shown in Table 1.

[0090] Table 1. Performance test results of high-activity, high-purity titanium boride powder for lithium-ion battery energy storage in Examples 1-4 and Comparative Examples 1-3.

[0091]

[0092] As shown in Table 1, the test results of Example 1 and Comparative Example 1 indicate that without the addition of polyol-boron ester prepolymer, the coating and dispersion effect of the precursor stage on titanium dioxide, boron carbide, and catalyst is lacking. Furthermore, the auxiliary effect of local mass transfer and boron source compensation in the boron-containing glass formed by the pyrolysis of the prepolymer is also lacking. Uneven contact between titanium dioxide and boron carbide and local boron deficiency lead to insufficient carbothermic reduction and boronization reactions, resulting in an increase in residual titanium dioxide, boron carbide, and other secondary phases, and a decrease in phase purity. Simultaneously, the newly formed titanium boride grains lack spatial isolation and wetting control of the transient glass phase, leading to an increase in powder particle size. The coarse particles and high impurity content hinder rearrangement and necking during hot-pressing densification, resulting in a decrease in the relative density of the sintered body under the same sintering conditions and a decrease in the sintering activity of the powder. This is detrimental to its formation of a uniformly dispersed functional phase when used as a conductive ceramic component of lithium-ion battery energy storage electrodes or as a coating material for energy storage batteries.

[0093] As shown in Table 1, the test results of Example 1 and Comparative Example 2 reveal that without the addition of iron oxide / nitrogen-doped carbon quantum dots, the system lacks well-dispersed iron-based catalytic centers and highly active carbon sources. This significantly weakens the kinetics of carbothermic reduction and borination reactions, resulting in a slower and less uniform conversion of titanium dioxide to titanium boride. Locally, titanium dioxide, titanium carbide, and boron carbide secondary phases are more likely to remain, leading to a decrease in the purity of the titanium boride phase. Due to the lack of uniformly distributed interfacial activation centers and reaction sites, the formation of titanium boride is more characterized by the slow growth and maturation of a small number of crystal nuclei in a high-temperature and glassy phase environment. Macroscopically, this manifests as increased powder particle size and coarser, denser aggregates. Although the polyol-boron ester prepolymer can still improve mixing in the precursor stage and form a boron oxide glassy phase at high temperatures, promoting particle rearrangement and densification to some extent, its sintering activity is limited by insufficient powder activity and an increased proportion of impurities, resulting in a decrease in the relative density of the sintered body and a decline in the sintering activity of the powder.

[0094] As shown in Table 1, the test results of Example 1 and Comparative Example 3 reveal that without the addition of iron oxide / nitrogen-doped carbon quantum dots and polyol-boron ester prepolymer, the system degenerates into a traditional carbothermal reduction using titanium dioxide / boron carbide / carbon black at a lower temperature. This lacks both iron-based catalysis and a highly active carbon source to lower the reaction temperature, as well as the coating and dispersion of the prepolymer in the precursor stage and the mass transfer and isolation effect of the boron oxide glass phase at high temperatures. Consequently, the reduction and boronization processes of titanium dioxide are difficult to fully proceed, resulting in residual titanium dioxide, boron carbide, and... The amount of secondary phases such as titanium carbide increases significantly, and the phase purity decreases. At the same time, the initial agglomeration of particles in the precursor is severe. At high temperatures, titanium boride grains continue to grow without liquid phase isolation, forming coarse and dense agglomerates, and the powder particle size increases. The coarse, low-activity powder with more impurities has a deteriorated densification ability under the same hot-pressing conditions, the relative density of the sintered body decreases, and the sintering activity of the powder decreases. It is difficult to meet the basic requirements of fine, high-purity and good dispersibility for the conductive ceramic components of lithium-ion battery energy storage electrodes and the coating materials of energy storage battery electrodes.

[0095] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing highly active, high-purity titanium boride powder for lithium-ion battery energy storage, characterized in that, The preparation method includes: S1: Citric acid, urea and ferric chloride are added to deionized water to obtain a mixture. The pH is adjusted with ammonia to obtain reaction solution A. The mixture is reacted, centrifuged, washed and dried to obtain iron oxide / nitrogen-doped carbon quantum dots. Boric acid and glycerol are mixed and heated under a nitrogen atmosphere and stirred to obtain polyol-boron ester prepolymer. S2: Add titanium dioxide, boron carbide, carbon black and iron oxide / nitrogen-doped carbon quantum dots to ethanol to obtain a mixed suspension, add polyol-boron ester prepolymer and ultrasonically disperse to obtain precursor slurry, vacuum dry the precursor slurry, grind and sieve to obtain precursor composite powder. S3: The precursor composite powder is placed in a graphite crucible and subjected to programmed carbothermic reduction under an argon atmosphere: the temperature is raised to the first temperature and held, then raised to the second temperature and held, and cooled to room temperature with the furnace to obtain crude titanium boride. S4: Crude titanium boride is dispersed in hydrochloric acid solution to obtain an acid washing solution. The solution is stirred at room temperature and centrifuged to obtain a crude product. The product is washed with deionized water, then with hot deionized water, and finally with ethanol. After drying, high-activity and high-purity titanium boride powder for lithium-ion battery energy storage is obtained.

2. The method for preparing high-activity, high-purity titanium boride powder for lithium-ion battery energy storage according to claim 1, characterized in that, In S1: The molar ratio of citric acid to urea is 1:(3-8).

3. The method for preparing high-activity, high-purity titanium boride powder for lithium-ion battery energy storage according to claim 1, characterized in that, In S1: The molar ratio of citric acid to ferric chloride is 1:(0.05-0.2); The ratio of the total mass of citric acid, urea, and ferric chloride to the volume of deionized water is 1 g:(15-25) mL.

4. The method for preparing high-activity, high-purity titanium boride powder for lithium-ion battery energy storage according to claim 1, characterized in that, In S1: The molar ratio of boric acid to glycerol is 1:(1.5-2.5); The temperature at which the boric acid and glycerol are mixed and heated is 130-160℃.

5. The method for preparing high-activity, high-purity titanium boride powder for lithium-ion battery energy storage according to claim 1, characterized in that, In S2: The molar ratio of titanium dioxide, boron carbide and carbon black is 2:1:(2.8-3.0).

6. The method for preparing high-activity, high-purity titanium boride powder for lithium-ion battery energy storage according to claim 1, characterized in that, In S2: The amount of iron oxide / nitrogen-doped carbon quantum dots fed is 5-10% of the mass of titanium dioxide.

7. The method for preparing high-activity, high-purity titanium boride powder for lithium-ion battery energy storage according to claim 1, characterized in that, In S2: The solid-liquid mass ratio of the mixed suspension is 1:(5-10); The amount of the polyol-boron ester prepolymer fed is 15-25% of the mass of titanium dioxide.

8. The method for preparing high-activity, high-purity titanium boride powder for lithium-ion battery energy storage according to claim 1, characterized in that, In S3: The first temperature is 550-650℃; The second temperature is 1300-1400℃.

9. The method for preparing high-activity, high-purity titanium boride powder for lithium-ion battery energy storage according to claim 1, characterized in that, In S4: The mass-to-volume ratio of the crude titanium borate to the hydrochloric acid solution is 1g:(20-30)mL; The temperature of the hot deionized water is 75-85℃.

10. A high-activity, high-purity titanium boride powder for lithium-ion battery energy storage prepared by the preparation method according to any one of claims 1-9.

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