Manganese iron hydrogen phosphate material, preparation method and application thereof
By preparing manganese-iron hydrogen phosphate material, the problems of low energy density and poor safety of lithium iron phosphate batteries have been solved, achieving high plateau voltage and long cycle life. By utilizing the advantages of manganese resources, costs have been reduced, and battery performance and safety have been improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUIZHOU YAYOU NEW MATERIAL CO LTD
- Filing Date
- 2022-11-18
- Publication Date
- 2026-05-12
AI Technical Summary
Existing lithium iron phosphate batteries have low energy density, poor safety and cycle performance, and the high price and thermal runaway of nickel-cobalt materials necessitate importation, which affects their application in the battery field.
Using FexMn(1-x)HPO4, a material structure with manganese enriched in the core and iron enriched in the outer layer was prepared by controlling the feed ratio of divalent manganese salt and ferrous salt, thereby improving conductivity and cycle life. The reaction was stabilized by phosphate flow rate, and lithium manganese iron phosphate was prepared by liquid-phase synthesis and high-temperature sintering.
It improves the platform voltage and cycle life of lithium iron phosphate batteries, utilizes abundant domestic manganese resources, reduces costs, enhances safety, and makes up for the shortcomings of ternary lithium batteries and lithium iron phosphate batteries.
Smart Images
Figure CN116130647B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery materials technology, and in particular to a manganese-iron hydrogen phosphate material, its preparation method and application. Background Technology
[0002] Currently, the automotive power lithium batteries on the market are mainly ternary lithium batteries and lithium iron phosphate batteries. Ternary lithium batteries are characterized by a high single-cell platform voltage (3.7V) and a high theoretical specific capacity (278mAh / g). However, lithium iron phosphate batteries have a single-cell platform voltage of 3.2V and a theoretical specific capacity of 170mAh / g, resulting in a significantly lower energy density than ternary lithium batteries. Furthermore, lithium iron phosphate batteries also have lower volumetric energy density and lower low-temperature performance. However, ternary lithium batteries require the use of nickel-cobalt-manganese materials, and nickel-cobalt materials are particularly expensive, requiring large-scale imports. The inherent structural characteristics of nickel-cobalt materials lead to relatively poor safety, susceptibility to thermal runaway, and a much shorter cycle life compared to lithium iron phosphate materials.
[0003] In comparison, lithium iron phosphate batteries are safer, have better cycle performance, and their low-temperature performance can be improved by onboard auxiliary heating. For most southern regions, low-temperature performance is not a concern, and greatly improving the energy density of lithium iron phosphate batteries is an important development direction.
[0004] Therefore, there is an urgent need to provide a new type of material to improve the energy density of lithium iron phosphate batteries. Summary of the Invention
[0005] The first technical problem to be solved by this invention is:
[0006] A material of manganese phosphate is provided.
[0007] The second technical problem to be solved by this invention is:
[0008] A method for preparing the aforementioned manganese-iron hydrogen phosphate material is provided.
[0009] The third technical problem to be solved by this invention is:
[0010] Application of the aforementioned manganese-iron hydrogen phosphate material.
[0011] To solve the first technical problem, the technical solution adopted by the present invention is as follows:
[0012] A ferromanganese hydrogen phosphate material, wherein the chemical formula of the ferromanganese hydrogen phosphate material is:
[0013] Fe x Mn (1-x) HPO4;
[0014] Where x is between 0.1 and 0.7.
[0015] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:
[0016] The present invention relates to a manganese iron hydrogen phosphate material. By adding manganese to iron phosphate material, the manganese iron hydrogen phosphate material of the present invention achieves a platform voltage of up to 4.1V when used in lithium batteries. Compared with lithium iron phosphate batteries, it can significantly improve cycle life. In addition, manganese material is abundant and readily available in China, inexpensive, and has minimal environmental impact. The manganese iron hydrogen phosphate material of the present invention is sufficient to overcome the shortcomings of ternary and lithium iron phosphate batteries.
[0017] To solve the second technical problem, the technical solution adopted by the present invention is as follows:
[0018] A method for preparing the aforementioned manganese-iron phosphate material includes the following steps:
[0019] A mixture of ferrous salt solution, divalent manganese salt solution, and phosphate solution of equal concentration is reacted to obtain manganese ferric phosphate.
[0020] During the mixing process, in the first 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 2-3:7-8; in the middle 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 5-6:5-6; and in the last 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 7-8:2-3.
[0021] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:
[0022] 1. This invention changes the iron-manganese ratio between the core and shell of a material by controlling the feeding rates of divalent manganese salt and ferrous salt. This allows manganese to accumulate in the crystal core, preventing its dissolution during charging and discharging, while iron accumulates in the outer layer of the material, thereby improving its conductivity and cycle life.
[0023] 2. In the reaction process of this invention, the excess ratio of phosphate to metal salt is stabilized by controlling the phosphate flow rate.
[0024] According to one embodiment of the present invention, during the reaction, the total feed flow rate of the ferrous salt solution and the divalent manganese salt solution is constant. In the initial stage of the reaction, the feed rate of the divalent manganese salt is high and the feed rate of the ferrous salt is low. As the reaction proceeds, the feed rate of the divalent manganese salt decreases and the feed rate of the ferrous salt increases. In the later stage of the reaction, the feed rate of the divalent manganese salt is low and the feed rate of the ferrous salt is high.
[0025] According to one embodiment of the present invention, when mixing ferrous salt solution, divalent manganese salt solution, and phosphate solution of the same concentration, the feed is carried out in a parallel flow simultaneously. This results in more uniform mixing of the reaction system, relatively lower energy consumption, and continuous feeding if uniform iron and manganese abundance is required, thus improving batch stability.
[0026] According to one embodiment of the present invention, the ferrous salt includes at least one of ferrous sulfate, ferrous nitrate and ferrous chloride.
[0027] According to one embodiment of the present invention, the divalent manganese salt includes at least one of divalent manganese sulfate, manganese nitrate, and manganese chloride.
[0028] According to one embodiment of the present invention, the phosphate includes at least one of disodium hydrogen phosphate and sodium dihydrogen phosphate.
[0029] According to one embodiment of the present invention, the concentrations of the ferrous salt solution, the divalent manganese salt solution, and the phosphate solution are all 0.4-1.0 mol / L. The method for preparing the ferromanganese hydrogen phosphate material of the present invention is based on the liquid-phase synthesis of the ferromanganese hydrogen phosphate precursor. A stable molar ratio of metal to phosphorus and the molar ratio between the various metals are synthesized using a liquid-phase method. The prepared metal salt solution and phosphate are reacted under a suitable acidity environment to generate ferromanganese hydrogen phosphate precipitate. Solid-phase high-temperature sintering is then performed using ferromanganese hydrogen phosphate and a lithium source under a protective atmosphere to complete the crystal transformation of lithium manganese hydrogen phosphate, thereby giving it electrochemical activity.
[0030] According to one embodiment of the present invention, when mixing the ferrous salt solution, the divalent manganese salt solution, and the phosphate solution, an inert gas is introduced to purge air. The inert gas protection prevents the oxidation of the divalent manganese.
[0031] According to one embodiment of the present invention, the ratio of the amount of the phosphate solution to the total amount of the ferrous salt solution and the divalent manganese salt solution is 1:1.2 to 1.4.
[0032] According to one embodiment of the present invention, the temperature is 35-60°C during the mixing of ferrous salt solution, divalent manganese salt solution and phosphate solution of the same concentration; the temperature of the reaction is 80-90°C.
[0033] A method for preparing the aforementioned manganese-iron phosphate material includes the following steps:
[0034] 1. Preparation: Prepare equal volumes of ferrous salt and divalent manganese salt solutions, with ferric ion concentration of 0.4-1.0 mol / L and manganese ion concentration of 0.4-1.0 mol / L; prepare disodium hydrogen phosphate solution, containing phosphate ion concentration of 0.4-1.0 mol / L.
[0035] 2. Slurry preparation: Add disodium hydrogen phosphate solution to the reactor. The amount of disodium hydrogen phosphate should be 1.05-1.4 times the molar amount of metal ions. The liquid level should be higher than the stirring blade and the feed pipe outlet.
[0036] 3. Precipitation Synthesis: Start the stirring in the reactor, mix the ferrous salt solution and the divalent manganese salt solution of the same concentration at a volume ratio of x:1-x, where x is 0.1-0.7. Simultaneously, pump the ammonium dihydrogen phosphate solution into the stirred reactor with the pre-existing bottom material in parallel flow. Inert gas (nitrogen or argon) is introduced below the liquid surface in the reactor to remove internal air. Then, start feeding the material, maintaining an inert atmosphere inside the reactor. After the reaction is complete, separate and dry the mother liquor to obtain ferric manganese hydrogen phosphate.
[0037] Another aspect of the present invention relates to the application of the aforementioned ferromanganese hydrogen phosphate material in batteries for electric vehicles. This includes the ferromanganese hydrogen phosphate material described in the first aspect embodiment above. Since this application employs all the technical solutions of the aforementioned ferromanganese hydrogen phosphate material, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.
[0038] Another aspect of the present invention relates to the application of the aforementioned ferromanganese hydrogen phosphate material in automobiles. This includes the ferromanganese hydrogen phosphate material as described in the first aspect embodiment above. Since this application employs all the technical solutions of the aforementioned ferromanganese hydrogen phosphate material, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.
[0039] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description
[0040] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0041] Figure 1 This is a flowchart of the method for preparing manganese-iron hydrogen phosphate material in Example 1.
[0042] Figure 2 This is a 200nm scanning electron microscope image of the manganese-iron hydrogen phosphate material obtained in Example 1.
[0043] Figure 3 This is a 2μm scanning electron microscope image of the manganese iron hydrogen phosphate material obtained in Example 1. Detailed Implementation
[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of the present invention.
[0045] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.
[0046] Example 1
[0047] A method for preparing ferromanganese hydrogen phosphate material includes the following steps:
[0048] 1. Preparation: Prepare 3L of equal volumes of ferrous chloride solution and manganese chloride solution, with ferrous ion concentration of 1.0mol / L and manganese ion concentration of 1.0mol / L; mix the two metal salt solutions evenly and set aside. Prepare 7.2L of disodium hydrogen phosphate solution, with phosphate ion concentration of 1.0mol / L.
[0049] 2. Slurry preparation: Add 1.2L of disodium hydrogen phosphate solution to the reactor. The liquid level should be higher than the stirring blade and the feed pipe outlet. Open the nitrogen valve so that micro-bubbles emerge below the liquid surface and ventilate for 10 minutes.
[0050] 3. Precipitation Synthesis: The reactor was stirred and ferrous chloride solution, manganese chloride solution, and disodium hydrogen phosphate solution were simultaneously pumped into the stirred reactor containing the pre-existing substrate. Feeding began at 35°C. For the first third of the reaction time, the feed volume ratio of ferrous chloride solution to manganese chloride solution was 2:7; for the middle third, it was 5:6; and for the final third, it was 7:2. An inert atmosphere was maintained inside the reactor. After feeding, the temperature was raised to 80°C and stirred continuously for 2 hours. After the reaction was complete, the mother liquor was separated, washed, and dried to obtain ferromanganese hydrogen phosphate material. The scanning electron microscope image of the above ferromanganese hydrogen phosphate material is shown below. Figure 2-3 .in, Figure 2 The scale bar is 200 nm. Figure 3 The scale bar is 2μm.
[0051] Example 2
[0052] A method for preparing ferromanganese hydrogen phosphate material includes the following steps:
[0053] 1. Preparation: Prepare 3L of equal volumes of ferrous chloride solution and manganese chloride solution, with ferrous ion concentration of 1.0mol / L and manganese ion concentration of 1.0mol / L; mix the two metal salt solutions evenly and set aside. Prepare 7.2L of disodium hydrogen phosphate solution, with phosphate ion concentration of 1.0mol / L.
[0054] 2. Slurry preparation: Add 1.2L of disodium hydrogen phosphate solution to the reactor. The liquid level should be higher than the stirring blade and the feed pipe outlet. Open the nitrogen valve so that micro-bubbles emerge below the liquid surface and ventilate for 30 minutes.
[0055] 3. Precipitation Synthesis: The reactor was stirred and ferrous chloride solution, manganese chloride solution, and disodium hydrogen phosphate solution were simultaneously pumped into the stirred reactor containing the pre-existing substrate. Feeding began at 60°C. For the first third of the reaction, the feed volume ratio of ferrous chloride solution to manganese chloride solution was 3:8; for the middle third, it was 6:6; and for the final third, it was 8:3. An inert atmosphere was maintained inside the reactor. After feeding, the temperature was raised to 80°C and the reaction was continuously stirred for 2 hours. After the reaction was complete, the mother liquor was separated, washed, and dried to obtain ferric manganese hydrogen phosphate material.
[0056] Example 3
[0057] A method for preparing ferromanganese hydrogen phosphate material includes the following steps:
[0058] 1. Preparation: Prepare 3L of equal volumes of ferrous chloride solution and manganese chloride solution, with ferrous ion concentration of 1.0mol / L and manganese ion concentration of 1.0mol / L; mix the two metal salt solutions evenly and set aside. Prepare 7.2L of disodium hydrogen phosphate solution, with phosphate ion concentration of 1.0mol / L.
[0059] 2. Slurry preparation: Add 1.2L of disodium hydrogen phosphate solution to the reactor. The liquid level should be higher than the stirring blade and the feed pipe outlet. Open the nitrogen valve so that micro-bubbles emerge below the liquid surface and ventilate for 130 minutes.
[0060] 3. Precipitation Synthesis: The reactor was stirred and ferrous chloride solution, manganese chloride solution, and disodium hydrogen phosphate solution were simultaneously pumped into the stirred reactor containing the pre-existing substrate. Feeding began at 35°C. For the first third of the reaction, the feed volume ratio of ferrous chloride solution to manganese chloride solution was 3:8; for the middle third, it was 6:6; and for the final third, it was 8:3. An inert atmosphere was maintained inside the reactor. After feeding, the temperature was raised to 80°C and stirred continuously for 2 hours. After the reaction was complete, the mother liquor was separated, washed, and dried to obtain ferric manganese hydrogen phosphate material.
[0061] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A manganese-iron hydrogen phosphate material, characterized in that: The chemical formula of the ferromanganese hydrogen phosphate material is: Fe x Mn (1-x) HPO4; Where x ranges from 0.1 to 0.7; The preparation method of the aforementioned ferromanganese hydrogen phosphate material comprises the following steps: A mixture of ferrous salt solution, divalent manganese salt solution, and phosphate solution of equal concentration is reacted to obtain manganese ferric phosphate. During the mixing process, in the first 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 2-3:7-8; in the middle 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 5-6:5-6; and in the last 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 7-8:2-3.
2. A method for preparing the ferromanganese hydrogen phosphate material as described in claim 1, characterized in that: Includes the following steps: A mixture of ferrous salt solution, divalent manganese salt solution, and phosphate solution of equal concentration is reacted to obtain manganese ferric phosphate. During the mixing process, in the first 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 2-3:7-8; in the middle 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 5-6:5-6; and in the last 1 / 3 of the time, the feed volume ratio of ferrous salt solution to divalent manganese salt solution was 7-8:2-3.
3. The method according to claim 2, characterized in that: The ferrous salt includes at least one of ferrous sulfate, ferrous nitrate, and ferrous chloride.
4. The method according to claim 2, characterized in that: The divalent manganese salt includes at least one of divalent manganese sulfate, manganese nitrate, and manganese chloride.
5. The method according to claim 2, characterized in that: The phosphate includes at least one of disodium hydrogen phosphate and sodium dihydrogen phosphate.
6. The method according to claim 2, characterized in that: The concentrations of the ferrous salt solution, the divalent manganese salt solution, and the phosphate solution are all 0.4-1.0 mol / L.
7. The method according to claim 2, characterized in that: When mixing ferrous salt solutions, divalent manganese salt solutions, and phosphate solutions, an inert gas is introduced to remove air.
8. The method according to claim 2, characterized in that: The ratio of the amount of the phosphate solution to the total amount of the ferrous salt solution and the divalent manganese salt solution is 1:1.2~1.
4.
9. The method according to claim 2, characterized in that: During the mixing of ferrous salt solution, divalent manganese salt solution and phosphate solution of the same concentration, the temperature is 35-60℃; the reaction temperature is 80-90℃.
10. The application of the manganese iron hydrogen phosphate material as described in claim 1 in the battery of an electric vehicle.