Preparation method of lithium-rich manganese base with high compaction density

Abstract

The invention discloses a preparation method of a lithium-rich manganese base with high compaction density, and relates to the technical field of lithium ion batteries, the method comprises the following steps: firstly, a certain amount of nickel source, cobalt source and manganese source are weighed and dissolved in pure water, and the solution preparation concentration is 2.0 mol / L; 2, adding 5-20g of titanium citrate into the solution prepared in the step 1, and mixing; the operation in the step 2 is repeated, the same solution is prepared, the addition amount of the titanium citrate needs to be controlled, and the difference between the addition amount of the titanium citrate and the addition amount of the titanium citrate is about 10 g. The preparation method comprises the following steps: firstly, preparing a manganese-based material precursor by adopting a liquid phase method, in the precursor preparation process, adding citric acid titanium with different concentrations to prepare precursors with different doping concentrations, subsequently uniformly mixing the two precursors, subsequently supplementing a lithium source, and performing high-temperature solid-phase sintering to obtain the lithium-rich manganese-based material with high compaction density and high rate performance.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and particularly to a preparation method of a high tap density lithium-rich manganese-based material. Background Art

[0002] Existing lithium-rich manganese-based cathode materials show advantages of high energy density in the field of lithium-ion batteries. However, problems such as poor crystal structure stability, low lithium-ion diffusion rate, and many surface side reactions lead to serious attenuation of the rate performance of the materials during charge and discharge, making it difficult to simultaneously meet the requirements of high energy density and high power output. The traditional solid-phase synthesis method has defects such as uneven element distribution and uncontrollable particle morphology, resulting in a single particle size distribution of the materials and the inability to form an effective grading structure, which not only limits the construction of fast lithium-ion transport channels but also makes it difficult to balance the contradiction between tap density and electrochemical activity. Although some studies have attempted to improve the performance through element doping, most of them use single-concentration doping or post-doping processes, which are difficult to accurately control the crystal growth kinetics process, and the uniformity of the distribution of doping elements is insufficient, resulting in easy collapse of the structure of the materials during cycling and difficulty in synergistically improving the rate performance and energy density.

[0003] Based on this, a preparation method of a high tap density lithium-rich manganese-based material is now provided, which can eliminate the drawbacks of existing methods. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a high tap density lithium-rich manganese-based material to solve the problems in the background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A preparation method of a high tap density lithium-rich manganese-based material includes the following steps:

[0007] Step 1: First, weigh a certain amount of nickel source, cobalt source, and manganese source and dissolve them in pure water, and the concentration of the prepared solution is 2.0 mol / L;

[0008] Step 2: Add 5 - 20 g of titanium citrate to the solution prepared in Step 1 and mix them;

[0009] Step 3: Repeat the operation in Step 2 to prepare the same solution, and control the addition amount of titanium citrate. Note that the difference in the addition amounts between the two is about 10 g;

[0010] Step 4: Input the two metal solutions prepared in Step 2 and Step 3 into the reaction kettle respectively. The reaction kettle is connected to a nitrogen tank, and at the same time, the Na2CO3 solution as the precipitant and the NH3·H2O solution as the complexing agent are also added to the reaction kettle respectively by peristaltic pumps;

[0011] Step 5: Adjust the pH value and stirring speed of the solution in the reactor in Step 4;

[0012] Step 6: After the solution is fed and reacts for 18 h, the metal mixed solution feeding is completed, the stirring duration continues for 8 h, then the solution is filtered to remove the precipitate, washed with pure water, dried at 120 °C for 24 h, and finally sieved (200 mesh) to produce the target precursor product;

[0013] Step 7: Add the precursors with two different doping amounts obtained in Step 6 into water, add carbon source 1 and carbon source 2 at the same time, and then supplement the lithium source;

[0014] Step 8: Dry the obtained solution in an oven at a drying temperature of 120 °C, and grind it after drying until there are no obvious lumps.

[0015] Step 9: Place the ground powder in a sintering furnace for sintering, sinter for 3 - 12 h under the protection of an inert gas, the sintering temperature is 700 - 900 °C, and perform air flow pulverization after the temperature drops to room temperature to obtain the lithium-rich manganese-based material with graded particle sizes.

[0016] Based on the above technical solutions, the present invention also provides the following alternative technical solutions:

[0017] In an alternative solution: In Step 1, the nickel source is one or more of nickel chloride, nickel sulfate, nickel nitrite, and nickel hydroxide.

[0018] In an alternative solution: In Step 1, the cobalt source is one or more of cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, and cobalt acetate.

[0019] In an alternative solution: In Step 1, the manganese source is one or more of manganese sulfate, manganese nitrate, manganese chloride, and potassium permanganate.

[0020] In an alternative solution: In Step 3, the reactor maintains a constant temperature of 50 °C during the reaction, and the bottom liquid is ammonia water.

[0021] In an alternative solution: In Step 4, the pH value of the solution is between 8 and 9, and the stirring speed of the solution is between 400 and 700 rpm.

[0022] In an alternative solution: In Step 6, carbon source 1 and carbon source 2 are one or more of phenolic resin, polyvinyl alcohol, glucose, sucrose, starch, corn paste, and chitosan.

[0023] In an alternative solution: In Step 6, the lithium source may be one or more of lithium carbonate, lithium hydroxide, and lithium chloride.

[0024] In an alternative solution: In Step 1, Ni in the solution2+ : Co 2+ : Mn 2+ The cation molar ratio is 1:1:4.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. First, the present invention uses the liquid phase method to prepare a manganese-based material precursor. During the preparation of the precursor, titanium citrate with different concentrations is added to prepare precursors with different doping concentrations. Subsequently, the two precursors are mixed evenly, and then a lithium source is added. After high-temperature solid-phase sintering, a lithium-rich manganese-based material with high tap density and high rate performance is obtained.

[0027] 2. The present invention realizes different crystal growth rates by controlling the doping concentration of Ti element, generates particles with different particle sizes, thus realizing the grading effect of large and small particles. At the same time, doping can also ensure the stability of the crystal structure, improve the electrochemical performance of the lithium-rich manganese-based material, solve the problem of poor rate performance of the lithium-rich manganese-based material during use, and at the same time ensure high energy density. Description of the Drawings

[0028] Figure 1 It is the SEM diagram of the lithium-rich manganese-based synthesized by the present invention.

[0029] Figure 2 It is the operation flow chart of the present invention. Detailed Embodiments

[0030] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0031] In one embodiment, as Figure 1 - Figure 2 shown, a preparation method of a lithium-rich manganese-based material with high tap density includes the following steps:

[0032] Step 1: First, weigh a certain amount of nickel source, cobalt source, and manganese source and dissolve them in pure water. The solution concentration is 2.0 mol / L;

[0033] Step 2: Add 5 - 20 g of titanium citrate to the solution prepared in Step 1 and mix;

[0034] Step 3: Repeat the operation in Step 2 to prepare the same solution. The addition amount of titanium citrate needs to be controlled, and pay attention that the addition amounts of the two differ by about 10 g;

[0035] Step 4: Input the two metal solutions prepared in Step 2 and Step 3 into the reaction kettle respectively. The reaction kettle is connected to a nitrogen tank. At the same time, the Na2CO3 solution as the precipitating agent and the NH3·H2O solution as the complexing agent are also added to the reaction kettle by peristaltic pumps respectively;

[0036] Step 5: Adjust the pH value and stirring speed of the solution in the reactor in Step 4;

[0037] Step 6: After 18 h of reaction with the solution fed, when the metal mixed solution feeding is completed, continue stirring for 8 h, then filter out the precipitate from the solution, wash it with pure water, adjust the temperature to 120 °C and dry for 24 h, and finally sieve (200 mesh) to produce the target precursor product;

[0038] Step 7: Add the precursors with two different doping amounts obtained in Step 6 into water, add carbon source 1 and carbon source 2 simultaneously, and then supplement the lithium source;

[0039] Step 8: Dry the obtained solution in an oven at a drying temperature of 120 °C, and grind it after drying until there are no obvious lumps.

[0040] Step 9: Place the ground powder in a sintering furnace for sintering. Sinter for 3 - 12 h under the protection of inert gas, and the sintering temperature is 700 - 900 °C. After the temperature drops to room temperature, perform air flow pulverization to obtain the lithium-rich manganese-based material with graded particle sizes.

[0041] In one embodiment, in Step 1, the nickel source is one or more of nickel chloride, nickel sulfate, nickel nitrite, and nickel hydroxide.

[0042] In one embodiment, in Step 1, the cobalt source is one or more of cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, and cobalt acetate.

[0043] In one embodiment, in Step 1, the manganese source is one or more of manganese sulfate, manganese nitrate, manganese chloride, and potassium permanganate.

[0044] In one embodiment, in Step 3, the reactor maintains a constant temperature of 50 °C during the reaction, and the bottom liquid is ammonia water.

[0045] In one embodiment, in Step 4, the pH value of the solution is between 8 and 9, and the stirring speed of the solution is between 400 and 700 rpm.

[0046] In one embodiment, in Step 6, carbon source 1 and carbon source 2 are one or more of phenolic resin, polyvinyl alcohol, glucose, sucrose, starch, corn paste, and chitosan.

[0047] In one embodiment, in Step 6, the lithium source may be one or more of lithium carbonate, lithium hydroxide, and lithium chloride.

[0048] In one embodiment, in Step 1, Ni in the solution 2+ : Co 2+ : Mn 2+The molar ratio of cations is 1:1:4.

[0049] The present invention will be described in detail below with reference to the embodiments. The embodiments provide detailed implementation manners and specific operation processes on the premise of the technical solution of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0050] Embodiment 1:

[0051] Preparation steps:

[0052] First, take a certain amount of nickel source, cobalt source, and manganese source and dissolve them in pure water. The liquid preparation concentration is 2.0 mol / L (the molar ratio of Ni 2+ : Co 2+ : Mn 2 in the solution is 1:1:4). Then, add 5 g of titanium citrate to the solution; repeat the above operation to prepare the same solution, and the amount of titanium citrate added to this solution is 15 g; subsequently, continuously input the two mixed metal solutions into the reaction kettle respectively. The reaction kettle is connected to a nitrogen tank. At the same time, the Na2CO3 solution as the precipitating agent and the NH3·H2O solution as the complexing agent are also added to the reaction kettle by peristaltic pumps respectively. The system maintains a constant temperature of 50 °C during the reaction, and the bottom liquid is ammonia water; then adjust the pH value of the solution and the stirring speed. The pH value is between 8 and 9, and the stirring speed is between 400 and 700 rpm; next, after feeding and reacting for 18 h, the feeding of the metal mixed solution is completed, and the stirring duration continues for 8 h. Then, filter out the precipitate from the solution, wash it with pure water, adjust it to 120 °C and dry it for 24 h. Finally, sieve it (200 mesh) to produce the target precursor product; subsequently, add the two precursors with different doping amounts obtained according to a certain ratio to water, and at the same time add carbon source 1 and carbon source 2. The usage amounts of carbon source 1 and carbon source 2 are 0.1 wt% to 3 wt%, and then supplement the lithium source; then, dry the obtained solution in an oven at a drying temperature of 120 °C, and grind it after drying until there are no obvious lumps; finally, place the ground powder in a sintering furnace for sintering, sinter it for 3 - 12 h under the protection of an inert gas (N2), and the sintering temperature is 700 - 900 °C. After the temperature drops to room temperature, perform air flow pulverization to obtain the lithium-rich manganese-based material with graded particle sizes.

[0053] Observe the particles with different particle sizes between the particles

[0054] Embodiment 2:

[0055] The preparation steps are the same as those in Embodiment 1. The amount of titanium citrate added to the first solution is 10 g; the amount of titanium citrate added to the second solution is 20 g.

[0056] The materials selected are the same as those in Embodiment 1.

[0057] Embodiment 3:

[0058] The preparation steps are the same as those in Example 1. The amount of titanium citrate added to the first solution is 15 g; the amount of titanium citrate added to the second solution is 25 g.

[0059] Comparative Example 1:

[0060] First, a certain amount of nickel source, cobalt source, and manganese source are dissolved in pure water. The concentration of the liquid preparation is 2.0 mol / L (the molar ratio of Ni2+: Co2+: Mn2+ cations in the solution is 1:1:4). Then, 5 g of titanium citrate is added to the solution. Subsequently, the mixed metal solution is continuously input into the reaction kettle. The reaction kettle is connected to a nitrogen tank. At the same time, the Na2CO3 solution as the precipitant and the NH3·H2O solution as the complexing agent are also added to the reaction kettle by peristaltic pumps respectively. The system maintains a constant temperature of 50 °C during the reaction, and the bottom liquid is ammonia water. Then, the pH value and stirring speed of the solution are adjusted. The pH value is between 8 and 9, and the stirring speed is between 400 and 700 rpm. Next, after 18 h of feeding reaction, the feeding of the metal mixed solution is completed, and the stirring duration continues for 8 h. Then, the solution is filtered to filter out the precipitate, washed with pure water, dried at 120 °C for 24 h, and finally sieved (200 mesh) to produce the target precursor product. Subsequently, the two precursors with different doping amounts obtained are added to water according to a certain ratio, and carbon source 1 and carbon source 2 are added at the same time. The usage amounts of carbon source 1 and carbon source 2 are 0.1 wt% - 3 wt%. Then, the lithium source is supplemented. After that, the obtained solution is dried in an oven at a drying temperature of 120 °C, and then ground until there are no obvious lumps. Finally, the ground powder is placed in a sintering furnace for sintering, sintered for 3 - 12 h under the protection of an inert gas (N2), and the sintering temperature is 700 - 900 °C. After the temperature drops to room temperature, air flow pulverization is carried out to obtain the lithium-rich manganese-based material with graded particle sizes.

[0061] The materials selected are the same as those in Example 1.

[0062] Comparative Example 2:

[0063] First, take a certain amount of nickel source, cobalt source, and manganese source and dissolve them in pure water. The concentration of the liquid preparation is 2.0 mol / L (the molar ratio of Ni2+:Co2+:Mn2+ cations in the solution is 1:1:4). Then, add 10 g of titanium citrate to the solution. Subsequently, continuously input the mixed metal solution into the reaction kettle. The reaction kettle is connected to a nitrogen tank. At the same time, the Na2CO3 solution as the precipitant and the NH3·H2O solution as the complexing agent are also added to the reaction kettle using peristaltic pumps respectively. The system maintains a constant temperature of 50 °C during the reaction, and the bottom liquid is ammonia water. Then, adjust the pH value and stirring speed of the solution. The pH value is between 8 and 9, and the stirring speed is between 400 and 700 rpm. Next, after feeding and reacting for 18 h, the feeding of the metal mixed solution is completed, and the stirring duration continues for 8 h. Then, filter out the precipitate from the solution, wash it with pure water, adjust the temperature to 120 °C and dry it for 24 h. Finally, screen it (200 mesh) to produce the target precursor product. Subsequently, add the obtained two kinds of precursors with different doping amounts to water according to a certain ratio, and at the same time add carbon source 1 and carbon source 2. The usage amounts of carbon source 1 and carbon source 2 are 0.1 wt% - 3 wt%. Then, supplement the lithium source. After that, dry the obtained solution in an oven at a drying temperature of 120 °C, and grind it after drying until there are no obvious lumps. Finally, place the ground powder in a sintering furnace for sintering. Sinter for 3 - 12 h under the protection of inert gas (N2), and the sintering temperature is 700 - 900 °C. After the temperature drops to room temperature, perform air flow pulverization to obtain the lithium-rich manganese-based material with graded particle sizes.

[0064] The materials selected are the same as those in Example 1.

[0065] Comparative Example 2:

[0066] First, take a certain amount of nickel source, cobalt source, and manganese source and dissolve them in pure water. The concentration of the prepared liquid is 2.0 mol / L (the molar ratio of Ni2+, Co2+, and Mn2+ cations in the solution is 1:1:4). Then, add 15 g of titanium citrate to the solution. Subsequently, continuously input the mixed metal solution into the reaction kettle. The reaction kettle is connected to a nitrogen tank. At the same time, use a peristaltic pump to add the Na2CO3 solution as the precipitant and the NH3·H2O solution as the complexing agent to the reaction kettle respectively. The system maintains a constant temperature of 50 °C during the reaction, and the bottom liquid is ammonia water. Then, adjust the pH value of the solution and the stirring speed. The pH value is between 8 and 9, and the stirring speed is between 400 and 700 rpm. Next, after feeding and reacting for 18 h, the feeding of the metal mixed solution is completed, and the stirring duration continues for 8 h. Then, filter out the precipitate from the solution, wash it with pure water, adjust the temperature to 120 °C and dry it for 24 h. Finally, sieve it (200 mesh) to produce the target precursor product. Subsequently, add the obtained two kinds of precursors with different doping amounts to water according to a certain ratio, and at the same time add carbon source 1 and carbon source 2. The usage amounts of carbon source 1 and carbon source 2 are 0.1 wt% - 3 wt%. Then, supplement the lithium source. After that, dry the obtained solution in an oven at a drying temperature of 120 °C, and grind it after drying until there are no obvious lumps. Finally, place the ground powder in a sintering furnace for sintering. Sinter for 3 - 12 h under the protection of an inert gas (N2), and the sintering temperature is 700 - 900 °C. After the temperature drops to room temperature, perform air flow pulverization to obtain the lithium-rich manganese-based material with graded particle sizes.

[0067] The materials selected are the same as those in Example 1.

[0068] The measured tap densities of the above-mentioned Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are shown in Table 1.

[0069] Table 1:

[0070] experimental group compaction density Example 1 2.75 Example 2 2.71 Example 3 2.78 Comparative Example 1 2.65 Comparative Example 1 2.67 Comparative Example 2 2.63

[0071] As Figure 1 shown: Observe the particles with different particle sizes between the particles. The small particles are caused by high doping amounts, and the large particles are caused by smaller doping concentrations. The small particles fill the gaps between the large particles, achieving a better tap density.

[0072] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A preparation method of high-compaction-density lithium-rich manganese-based material, characterized in that It includes the following steps: Step 1: First, weigh a certain amount of nickel source, cobalt source, and manganese source and dissolve them in pure water. The concentration of the prepared solution is 2.0 mol / L. Step 2: Add 5 - 20 g of titanium citrate to the solution prepared in Step 1 and mix them. Step 3: Repeat the operation in Step 2 to prepare the same solution. Control the addition amount of titanium citrate, and note that the difference in the addition amounts between the two is about 10 g. Step 4: Input the two metal solutions prepared in Step 2 and Step 3 into the reaction kettle respectively. The reaction kettle is connected to a nitrogen tank. At the same time, use a peristaltic pump to add the Na2CO3 solution as the precipitant and the NH3·H2O solution as the complexing agent into the reaction kettle respectively. Step 5: Adjust the pH value and stirring speed of the solution in the reaction kettle in Step 4. Step 6: After the solution feeds and reacts for 18 h, the metal mixed solution feeding is completed. The stirring duration continues for 8 h. Then filter out the precipitate from the solution, wash it with pure water, adjust the temperature to 120 °C and dry it for 24 h. Finally, sieve it (200 mesh) to produce the target precursor product. Step 7: Add the two precursors with different doping amounts obtained in Step 6 into water, add carbon source 1 and carbon source 2 at the same time, and then supplement the lithium source. Step 8: Dry the obtained solution in an oven at a drying temperature of 120 °C. After drying, grind it until there are no obvious lumps. Step 9: Place the ground powder in a sintering furnace for sintering. Sinter for 3 - 12 h under the protection of an inert gas. The sintering temperature is 700 - 900 °C. After the temperature drops to room temperature, perform air flow pulverization to obtain the lithium-rich manganese-based material with a graded particle size distribution.

2. The method for preparing a lithium-rich manganese-based product with a high compaction density according to claim 1, wherein: In Step 1, the nickel source is one or more of nickel chloride, nickel sulfate, nickel nitrite, and nickel hydroxide.

3. A method for preparing a lithium-rich manganese-based material with high compaction density according to claim 1, characterized in that, In Step 1, the cobalt source is one or more of cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt carbonate, and cobalt acetate.

4. A preparation method of high-compaction-density lithium-rich manganese-based material according to claim 1, characterized in that, In Step 1, the manganese source is one or more of manganese sulfate, manganese nitrate, manganese chloride, and potassium permanganate.

5. A method for preparing a lithium-rich manganese-based material with high compaction density according to claim 1, characterized in that, In Step 3, the reaction kettle maintains a constant temperature of 50 °C during the reaction, and the bottom liquid is ammonia water.

6. A preparation method of high-compaction-density lithium-rich manganese-based material according to claim 1, characterized in that, In Step 4, the pH value of the solution is between 8 and 9, and the stirring speed of the solution is between 400 and 700 rpm.

7. A preparation method of high-compaction-density lithium-rich manganese-based material according to claim 1, characterized in that, In Step 6, carbon source 1 and carbon source 2 are one or more of phenolic resin, polyvinyl alcohol, glucose, sucrose, starch, corn paste, and chitosan.

8. A preparation method of a lithium-rich manganese-based material with high tap density according to claim 1, characterized in that, In Step 6, the lithium source may be one or more of lithium carbonate, lithium hydroxide, and lithium chloride.

9. A method for preparing a lithium-rich manganese-based material with high tap density according to claim 1, characterized in that, In step 1, Ni 2+ :Co 2+ :Mn 2+ The molar ratio of cations is 1:1:4.

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