Preparation method of titanium-doped ferrous phosphate and application thereof

Abstract

The application relates to the technical field of titanium-doped ferrous phosphate, and particularly discloses a preparation method of titanium-doped ferrous phosphate and application thereof, which comprises the following steps: S1, dissolving iron in mixed acid; S2, preparing a reaction stock solution; S3, preparing a titanium-containing solution; S4, co-precipitation reaction; and S5, post-treatment. The application proposes a preparation process for dissolving and reducing by using iron powder and iron concentrate powder as iron sources in cooperation with sulfur-phosphorus mixed acid, the Fe 3+ The application can precisely control the dissolution rate of ores and the precipitation behavior of impurities by using the sulfur-phosphorus mixed acid system, effectively reduce the residual sulfur impurities of the product, realize uniform lattice embedding of titanium elements by combining with a liquid-phase in-situ doping mechanism, and finally prepare high-purity, high-stability and high-quality titanium-doped ferrous phosphate, which takes into account the production cost, production safety and product performance, and meets the needs of large-scale industrialized continuous production.

Description

Technical Field

[0001] This invention relates to the field of titanium-doped ferrous phosphate technology, specifically to a method for preparing titanium-doped ferrous phosphate and its application. Background Technology

[0002] Titanium-doped ferrous phosphate, as a functional material, holds significant promise for applications in the field of lithium-ion battery cathode precursors. By introducing titanium into the ferrous phosphate lattice for doping, the crystal structure of the material can be effectively controlled, electronic conductivity and ion diffusion performance can be improved, thereby enhancing the electrochemical performance of the final lithium iron phosphate cathode material. Therefore, developing methods for preparing high-quality titanium-doped ferrous phosphate is of great significance for promoting the development of high-performance lithium iron phosphate cathode materials.

[0003] Currently, the main methods for preparing ferrous phosphate-based materials include high-temperature solid-state methods, liquid-phase coprecipitation methods, and hydrothermal methods. Among these, liquid-phase coprecipitation is the most commonly used method due to its mild process conditions and good product uniformity. In existing technologies for preparing titanium-doped ferrous phosphate, the conventional approach involves mixing ferrous salts such as ferrous sulfate with titanium sources such as titanium oxysulfate or titanium tetrachloride in the liquid phase, followed by the addition of phosphate and a precipitant for coprecipitation to obtain the titanium-doped ferrous phosphate precursor. However, this process has the following drawbacks: First, the ferrous salt raw materials, such as ferrous sulfate (a byproduct of titanium dioxide production), have high impurity content, making it difficult to meet the requirements for preparing high-purity doped products. Pure ferrous sulfate heptahydrate is expensive, and sulfur impurities are difficult to remove. Second, titanium sources are easily hydrolyzed in water, generating metatitanic acid precipitate, leading to uneven distribution of titanium elements during coprecipitation and making it difficult to achieve uniform doping of titanium in the ferrous phosphate lattice. Third, ferrous ions are easily oxidized to ferric iron during the reaction, affecting the phase purity and doping effect of the product. To address the aforementioned issues, recent studies have proposed a technical route for the direct preparation of ferrous phosphate using iron powder as the iron source and phosphoric acid as the phosphorus source. For example, patent CN121651307A discloses a method and system for preparing ferrous phosphate based on mixed acid and iron powder. The technical solution involves mixing dilute phosphoric acid and dilute sulfuric acid, adding pure iron powder to the mixed acid at an n(P):n(Fe) ratio of 0.67~1:1 to initiate an iron dissolution reaction, and waiting for the Fe in the ferrous solution to... 2+After the content reaches 3.5%~5.0%, ammonia is added to adjust the pH to 5.0~6.5. After aging, pressure filtration, washing, and drying, ferrous phosphate octahydrate is obtained. This technology provides a new approach for the high-purity preparation of ferrous phosphate, but it does not involve titanium doping. If a titanium source is introduced to achieve titanium doping based on this pure iron powder-phosphoric acid system, the following technical challenges will be faced: Titanium sources such as titanium oxysulfate have complex forms in acidic solutions, making it difficult to match their co-precipitation behavior with the iron-phosphoric acid system, easily leading to phase separation precipitation of titanium and iron, making uniform doping impossible. Regarding the selection of iron sources, existing technologies, whether for pure phosphoric acid systems or mixed acid systems, use pure iron powder as the sole iron source. The high production cost of pure iron powder results in high raw material costs for ferrous phosphate and its doped products. To reduce raw material costs, some technologies attempt to use a mixture of iron powder and iron ore powder or iron oxides as the iron source, but their process routes are usually geared towards the preparation of ferric phosphate, i.e., oxidizing divalent iron to trivalent iron. Compared with the titanium-doped ferrous phosphate of this invention, the Fe content needs to be maintained... 2+ The direction is opposite, and it cannot be directly applied to the preparation of titanium-doped ferrous phosphate. Furthermore, existing techniques for preparing ferrous phosphate generally suffer from the following shortcomings: First, there is a lack of effective protection against the oxidation of divalent iron. In the liquid-phase reaction system, Fe... 2+ It is readily oxidized to Fe by dissolved oxygen. 3+ For the preparation of titanium-doped ferrous phosphate, Fe 3+ The formation of impurities not only affects the phase purity of the product but may also co-precipitate with titanium ions, forming a heterogeneous phase that severely interferes with the uniform doping of titanium. Secondly, process safety needs improvement. The reaction of iron powder with acid produces flammable and explosive hydrogen gas. In existing technologies, when iron powder is directly reacted with mixed acid to prepare ferrous liquid, hydrogen production is unavoidable, requiring additional treatment of large amounts of hydrogen, and there is a lack of effective means to control the amount of hydrogen produced. Thirdly, the technical challenges of using iron concentrate as a partial iron source remain unresolved. Iron concentrate, mainly composed of Fe2O3 or Fe3O4, is inexpensive and an ideal source of cheap iron. However, iron concentrate is chemically stable, and its dissolution rate is slow and inefficient under conventional acid dissolution conditions; simultaneously, the iron dissolved from iron concentrate is mainly Fe... 3+ It exists in the form required by ferrous phosphate, with Fe 2+ Valence inconsistency. Currently, there is no effective technical solution to address the low dissolution efficiency and valence conversion issues of inexpensive iron concentrate while simultaneously utilizing it in the preparation of titanium-doped ferrous phosphate.

[0004] Therefore, there is an urgent need to develop a method for preparing titanium-doped ferrous phosphate that can use inexpensive iron concentrate as part of the iron source, achieve uniform doping of titanium in the ferrous phosphate lattice, effectively control the oxidation of ferrous iron, and ensure process safety. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing titanium-doped ferrous phosphate and its application, solving problems such as high raw material costs, easy oxidation of ferrous iron, hydrogen safety hazards, difficulty in effectively utilizing iron concentrate, and lack of effective means for uniform titanium doping through co-precipitation with titanium sources in existing ferrous phosphate preparation technologies.

[0006] In a first aspect, the present invention provides a method for preparing titanium-doped ferrous phosphate, comprising the following steps: S1. Mixed Acid Dissolution of Iron: A mixed acid solution is prepared by mixing phosphoric acid and sulfuric acid. An iron source is added to carry out the acid dissolution reaction. After the reaction is completed, the solution is filtered and the filtrate is collected. The molar ratio of phosphoric acid to sulfuric acid is 1~2:2~1, and the mass percentage concentration of the mixed acid solution is 20%~35%. The iron source is a mixture of iron powder and iron concentrate, and the mass ratio of iron powder to iron concentrate is 1:1~3. The molar ratio of total iron in the iron source to phosphoric acid is 1.48~1.52:1. S2. Preparation of reaction stock solution: Add antioxidant to the filtrate to obtain reaction stock solution; S3. Preparation of titanium-containing solution: Dissolve the titanium source in sulfuric acid solution to prepare a titanium-containing solution; S4. Co-precipitation reaction: Under inert gas protection, the reaction stock solution, the titanium-containing solution and ammonia water are subjected to a co-precipitation reaction, and the reaction pH is controlled to be 4.5~5.5 to obtain a precipitated slurry. S5. Post-processing: The precipitated slurry is filtered, washed, and dried to obtain titanium-doped ferrous phosphate product.

[0007] Furthermore, in S1, the temperature of the acid dissolution reaction is 40~80℃.

[0008] Furthermore, in S2, the antioxidant is selected from one or more of ascorbic acid, phytic acid, ethylenediaminetetraacetic acid, and water-soluble vitamin E.

[0009] Furthermore, in S3, the titanium source is selected from one or more of titanium citrate, titanium malate, titanium tartrate, and titanium oxysulfate.

[0010] Furthermore, in S4, the temperature of the coprecipitation reaction is 40~60℃.

[0011] Furthermore, in S5, before filtration, the precipitated slurry is allowed to stand and age for 1-2 hours.

[0012] Secondly, the present invention also provides a titanium-doped ferrous phosphate as described in the first aspect.

[0013] Thirdly, the present invention also provides the application of titanium-doped ferrous phosphate in lithium-ion battery cathode materials as described in the second aspect.

[0014] Compared with existing technologies, this solution has the following advantages: 1. Significantly Reduced Raw Material Costs: This invention uses inexpensive iron concentrate to replace part of the high-cost pure iron powder as the iron source. The price of iron concentrate is typically only 1 / 3 to 1 / 2 of that of pure iron powder. By controlling the mass ratio of iron powder to iron concentrate to 1:1 to 3, the raw material cost of ferrous phosphate is significantly reduced while ensuring product quality.

[0015] 2. Achieving safe and controllable process: This invention utilizes the simultaneous addition of iron powder and iron concentrate to a mixed acid system, allowing the iron powder to reduce the Fe dissolved from the iron concentrate. 3+ Simultaneously, the amount of hydrogen produced by the side reaction is actively controlled by adjusting the ratio of iron powder to iron concentrate. Iron powder preferentially reacts with Fe. 3+ The reduction reaction does not produce hydrogen gas; the remaining iron powder then reacts with acid to produce hydrogen gas. By precisely proportioning the components, the hydrogen production rate can be controlled within a safe range, overcoming the safety hazards of uncontrollable hydrogen production in traditional iron powder-acid systems.

[0016] 3. Effectively prevents Fe 2+ Oxidation to ensure high product purity: This invention adds antioxidants such as ascorbic acid, phytic acid, ethylenediaminetetraacetic acid, and water-soluble vitamin E to the reaction stock solution. Nitrogen gas is purged throughout the co-precipitation reaction for protection. These dual measures effectively prevent Fe oxidation. 2+ Oxidized to Fe 3+ .

[0017] 4. Achieving uniform doping of titanium in the ferrous phosphate lattice: This invention achieves uniform doping of titanium by adding the titanium-containing solution, the reaction stock solution, and ammonia water in a co-precipitation stage, and controlling the pH at 4.5~5.5 throughout the process, thus achieving uniform doping of Ti. 4+ with Fe 2+ PO4 3- Simultaneous precipitation enabled atomic-level uniform doping of titanium in the ferrous phosphate lattice. Attached Figure Description

[0018] Figure 1 This is a SEM image of the titanium-doped ferrous phosphate prepared in Example 1 of the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 This embodiment provides a method for preparing titanium-doped ferrous phosphate, the specific steps of which are as follows: S1, Mixed acid iron dissolution Take 85% concentrated phosphoric acid and 98% concentrated sulfuric acid, mix them in a molar ratio of phosphoric acid:sulfuric acid = 1:1, and dilute with water to prepare a mixed acid solution with a mass concentration of 25%. Place the mixed acid solution in a reaction vessel and heat it to 60°C.

[0021] Weigh out the iron source according to a total iron content to phosphoric acid molar ratio of 1.50:1, wherein the mass ratio of iron powder to iron concentrate is 1:1.5. Add the iron powder and iron concentrate simultaneously to the above mixed acid solution and stir until the iron source is fully dissolved. After the reaction is complete, filter to remove insoluble residue, collect the filtrate, and obtain the filtrate.

[0022] S2, Preparation of the reaction stock solution Ascorbic acid and phytic acid were added to the filtrate as antioxidants. The amount of ascorbic acid added was 2% of the total mass of the iron source, and the amount of phytic acid added was 0.5% of the total mass of the iron source. The mixture was stirred evenly to obtain the reaction stock solution.

[0023] S3, Preparation of titanium-containing liquid Titanium oxysulfate was dissolved in a 10% (w / w) dilute sulfuric acid solution to prepare Ti. 4+ A titanium-containing solution with a concentration of 0.1 mol / L is prepared for use. The amount of titanium source added is based on the molar ratio of titanium to iron in the final product, Ti:Fe = 0.02:1.

[0024] S4, coprecipitation reaction Under a nitrogen atmosphere, the reaction stock solution, titanium-containing solution, and ammonia water were simultaneously added to the reactor in a parallel flow. The feeding rate was controlled to ensure the co-precipitation reaction time was approximately 1 hour. During the reaction, the pH value of the reaction system was maintained between 4.5 and 5.5 throughout by adjusting the dropping rate of the ammonia water, and the reaction temperature was controlled at 40°C. After the reaction was completed, the feeding was stopped, and the mixture was stirred and aged for another 1.5 hours under nitrogen protection to obtain a precipitate slurry containing titanium-doped ferrous phosphate.

[0025] S5, Post-processing The precipitated slurry was filtered, and the filter cake was repeatedly washed with deionized water until no sulfate ions were detected in the washing liquid. The filter cake was then vacuum dried at 60°C to constant weight to obtain the titanium-doped ferrous phosphate product. Its SEM image is shown below. Figure 1 As shown.

[0026] Example 2 S1, Mixed acid iron dissolution Take 85% concentrated phosphoric acid and 98% concentrated sulfuric acid, mix them in a molar ratio of phosphoric acid:sulfuric acid = 1.5:1, and dilute with water to prepare a 30% (w / w) mixed acid solution. Place the mixed acid solution in a reaction vessel and heat it to 70°C.

[0027] Weigh out the iron source according to a molar ratio of total iron to phosphoric acid of 1.48:1, wherein the mass ratio of iron powder to iron concentrate is 1:1.2. Add the iron powder and iron concentrate to the above mixed acid solution simultaneously, stir until the iron source is fully dissolved, filter after the reaction is complete, and collect the filtrate.

[0028] S2, Preparation of the reaction stock solution Add ascorbic acid and water-soluble vitamin E to the filtrate as antioxidants. The amount of ascorbic acid added is 1.5% of the total mass of the iron source, and the amount of water-soluble vitamin E added is 0.3% of the total mass of the iron source. Stir well to obtain the reaction stock solution.

[0029] S3, Preparation of titanium-containing liquid Titanium citrate was dissolved in a 10% (w / w) dilute sulfuric acid solution to prepare Ti. 4+ A titanium-containing solution with a concentration of 0.08 mol / L is prepared for use. The amount of titanium source added is based on a final product Ti:Fe ratio of 0.015:1 (molar ratio).

[0030] S4, coprecipitation reaction Under a nitrogen atmosphere, the reaction stock solution, titanium-containing solution, and ammonia water were simultaneously added to the reactor in a parallel flow, with the feeding rate controlled to ensure a co-precipitation reaction time of approximately 1.2 hours. During the reaction, the pH of the reaction system was maintained between 4.8 and 5.2 throughout by adjusting the ammonia water dripping rate, and the reaction temperature was controlled at 45°C. After the reaction was completed, feeding was stopped, and the mixture was stirred and aged for another 2 hours under nitrogen protection to obtain a precipitated slurry.

[0031] S5, Post-processing Same as Example 1.

[0032] Example 3 S1, Mixed acid iron dissolution Take 85% concentrated phosphoric acid and 98% concentrated sulfuric acid, mix them in a molar ratio of phosphoric acid:sulfuric acid = 2:1, and dilute with water to prepare a mixed acid solution with a mass concentration of 20%. Place the mixed acid solution in a reaction vessel and heat it to 80°C.

[0033] Weigh out the iron source according to a molar ratio of total iron to phosphoric acid of 1.52:1, wherein the mass ratio of iron powder to iron concentrate is 1:2. Add the iron powder and iron concentrate to the above mixed acid solution simultaneously, stir until the iron source is fully dissolved, filter after the reaction is complete, and collect the filtrate.

[0034] S2, Preparation of the reaction stock solution Ethylenediaminetetraacetic acid (EDTA) and phytic acid were added to the filtrate as antioxidants. The amount of EDTA added was 1% of the total mass of the iron source, and the amount of phytic acid added was 0.8% of the total mass of the iron source. The mixture was stirred evenly to obtain the reaction stock solution.

[0035] S3, Preparation of titanium-containing liquid Titanium malate was dissolved in a 10% (w / w) dilute sulfuric acid solution to prepare Ti. 4+ A titanium-containing solution with a concentration of 0.12 mol / L is prepared for use. The amount of titanium source added is based on a final product Ti:Fe ratio of 0.025:1 (molar ratio).

[0036] S4, coprecipitation reaction Under a nitrogen atmosphere, the reaction stock solution, titanium-containing solution, and ammonia water were simultaneously added to the reactor in a parallel flow, with the feeding rate controlled to ensure a co-precipitation reaction time of approximately 0.8 hours. During the reaction, the pH of the reaction system was maintained between 4.5 and 5.5 throughout by adjusting the ammonia water dripping rate, and the reaction temperature was controlled at 55°C. After the reaction was completed, feeding was stopped, and the mixture was stirred and aged for another 1 hour under nitrogen protection to obtain a precipitated slurry.

[0037] S5, Post-processing Same as Example 1.

[0038] Example 4 S1, Mixed acid iron dissolution Take 85% concentrated phosphoric acid and 98% concentrated sulfuric acid, mix them in a molar ratio of phosphoric acid:sulfuric acid = 1:2, and dilute with water to prepare a 35% (w / w) mixed acid solution. Place the mixed acid solution in a reaction vessel and heat it to 40°C.

[0039] Weigh out the iron source according to a molar ratio of total iron to phosphoric acid of 1.50:1, wherein the mass ratio of iron powder to iron concentrate is 1:1. Add the iron powder and iron concentrate to the above mixed acid solution simultaneously, stir until the iron source is fully dissolved, filter after the reaction is complete, and collect the filtrate.

[0040] S2, Preparation of the reaction stock solution Add ascorbic acid as an antioxidant to the filtrate. The amount of ascorbic acid added is 3% of the total mass of the iron source. Stir well to obtain the reaction stock solution.

[0041] S3, Preparation of titanium-containing liquid Titanium tartrate was dissolved in a 10% (w / w) dilute sulfuric acid solution to prepare Ti. 4+ A titanium-containing solution with a concentration of 0.1 mol / L is prepared for use. The amount of titanium source added is based on a final product Ti:Fe ratio of 0.02:1 (molar ratio).

[0042] S4, coprecipitation reaction Under a nitrogen atmosphere, the reaction stock solution, titanium-containing solution, and ammonia water were simultaneously added to the reactor in a parallel flow, with the feeding rate controlled to ensure a co-precipitation reaction time of approximately 1.5 hours. During the reaction, the pH of the reaction system was maintained between 4.5 and 5.5 throughout by adjusting the ammonia water dripping rate, and the reaction temperature was controlled at 60°C. After the reaction was completed, feeding was stopped, and the mixture was stirred and aged for another 1.5 hours under nitrogen protection to obtain a precipitated slurry.

[0043] S5, Post-processing Same as Example 1.

[0044] Comparative Example 1 (No antioxidants added) The other conditions are exactly the same as in Example 1, except that no antioxidant is added in step S2, and the filtrate is used directly as the reaction stock solution for subsequent reactions.

[0045] Results: During the coprecipitation reaction, the color of the original reaction solution gradually changed from light green to yellowish-brown, indicating that Fe 2+ Oxidized to Fe 3+ The final product was light yellow, and FePO4 impurity peaks appeared in the XRD pattern, indicating a significant decrease in product purity.

[0046] Comparative Example 2 (no iron concentrate added, iron powder used as the iron source only) The other conditions are exactly the same as in Example 1, except that in step S1, only iron powder is used as the iron source (the amount of iron powder added is calculated based on a total iron element to phosphate molar ratio of 1.50:1), and no iron concentrate is added.

[0047] Results: The raw material cost increased by approximately 40% compared to Example 1. Due to the vigorous reaction between iron powder and acid, a large amount of hydrogen was generated, reducing the safety of the reaction process.

[0048] Comparative Example 3 (no aging, filtered directly after reaction). The other conditions are exactly the same as in Example 1, except that: after the reaction in step S4, no aging is performed, and the precipitated slurry is directly filtered, washed and dried.

[0049] Results: The precipitate particles were fine and colloidal, making filtration difficult (filtering time increased by approximately 3 times), the filtrate was turbid, and some fine particles passed through the filter, causing material loss. The titanium element in the product was unevenly distributed, resulting in poor doping effect.

[0050] Comparative Example 4 (pH control range deviated, maintained at pH=6.5 throughout) The other conditions are exactly the same as in Example 1, except that the pH value of the reaction system is maintained at 6.5 throughout the S4 step, which is outside the range of 4.5 to 5.5 of this invention.

[0051] Results: TiO2 (anatase) impurity peaks appeared in the XRD pattern of the product, and EDS surface scanning showed that the titanium element was not uniformly distributed, indicating that titanium was not effectively incorporated into the ferrous phosphate lattice, but precipitated separately in the form of metatitanic acid.

[0052] Comparative Example 5 (The ratio of phosphoric acid to sulfuric acid in the mixed acid solution deviates from the original ratio of phosphoric acid to sulfuric acid = 1:4). All other conditions are exactly the same as in Example 1, except that in step S1, the ratio of phosphoric acid to sulfuric acid is 1:4.

[0053] Results: The product S impurities exceeded the standard, and the product purity decreased; the product D10 decreased, making filtration difficult (the filtration time was extended by about 1.5 times), and some fine particles passed through the filter, causing material loss.

[0054] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing titanium-doped ferrous phosphate, characterized in that: Includes the following steps: S1. Mixed Acid Dissolution of Iron: A mixed acid solution is prepared by mixing phosphoric acid and sulfuric acid. An iron source is added to carry out the acid dissolution reaction. After the reaction is completed, the solution is filtered and the filtrate is collected. The molar ratio of phosphoric acid to sulfuric acid is 1~2:2~1, and the mass percentage concentration of the mixed acid solution is 20%~35%. The iron source is a mixture of iron powder and iron concentrate, and the mass ratio of iron powder to iron concentrate is 1:1~3. The molar ratio of total iron in the iron source to phosphoric acid is 1.48~1.52:

1. S2. Preparation of reaction stock solution: Add antioxidant to the filtrate to obtain reaction stock solution; S3. Preparation of titanium-containing solution: Dissolve the titanium source in sulfuric acid solution to prepare a titanium-containing solution; S4. Co-precipitation reaction: Under inert gas protection, the reaction stock solution, the titanium-containing solution and ammonia water are subjected to a co-precipitation reaction, and the reaction pH is controlled to be 4.5~5.5 to obtain a precipitated slurry. S5. Post-processing: The precipitated slurry is filtered, washed, and dried to obtain titanium-doped ferrous phosphate product.

2. The method for preparing titanium-doped ferrous phosphate according to claim 1, characterized in that: In S1, the temperature of the acid dissolution reaction is 40~80℃.

3. The method for preparing titanium-doped ferrous phosphate according to claim 1, characterized in that: In S2, the antioxidant is selected from one or more of ascorbic acid, phytic acid, ethylenediaminetetraacetic acid, and water-soluble vitamin E.

4. The method for preparing titanium-doped ferrous phosphate according to claim 1, characterized in that: In S3, the titanium source is selected from one or more of titanium citrate, titanium malate, titanium tartrate, and titanium oxysulfate.

5. The method for preparing titanium-doped ferrous phosphate according to claim 1, characterized in that: In S4, the temperature of the coprecipitation reaction is 40~60℃.

6. The method for preparing titanium-doped ferrous phosphate according to claim 1, characterized in that: In step S5, before filtration, the precipitated slurry is allowed to stand and age for 1-2 hours.

7. A titanium-doped ferrous phosphate, characterized in that: It is prepared by any one of claims 1 to 6.

8. The application of titanium-doped ferrous phosphate as described in claim 7 in the preparation of cathode materials for lithium-ion batteries.

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