A modified lithium manganate electrode material and a method for modifying the same
By modifying lithium manganese oxide electrode materials with hydrogen peroxide solution, the problems of complex surface modification and poor performance were solved, and the lithium-ion diffusion rate and electrochemical performance were improved, making it suitable for the industrial production of lithium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2024-04-24
- Publication Date
- 2026-05-22
AI Technical Summary
Existing lithium manganese oxide electrode materials suffer from complex surface modification processes and poor performance, resulting in long lithium-ion diffusion and electron transport paths, and the material surface is prone to microcracks, which affect electrochemical performance.
A lithium manganese oxide electrode material with high surface smoothness was prepared by mixing hydrogen peroxide solution with lithium manganese oxide, including stirring, filtering, washing and drying, and optimizing parameters such as concentration, stirring rate and temperature.
It effectively removes impurities from the surface of lithium manganese oxide, inhibits particle agglomeration, increases the Li+ diffusion rate, and enhances electrochemical performance. It is suitable for industrial production and is environmentally friendly.
Smart Images
Figure CN118495592B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium battery technology, and in particular to a modified lithium manganese oxide electrode material and its modification method. Background Technology
[0002] Electrode materials are a crucial component of lithium-ion batteries, and their performance determines the battery's energy density and lifespan. Therefore, the healthy development of electrode materials is the most critical technological challenge for lithium-ion batteries. Among existing electrode materials, lithium cobalt oxide (LiCoO2), as the first-generation commercially available electrode material, is considered the most mature electrode material for lithium-ion batteries used in 3C electric vehicles. It has advantages such as a high discharge platform, good cycle performance, and a simple synthesis process. However, this material contains cobalt, an element with high toxicity, and cobaltate resources are relatively scarce.
[0003] Therefore, spinel lithium manganese oxide electrode material has emerged. It not only possesses all the advantages of lithium cobalt oxide electrode material, but is also non-toxic, environmentally friendly, and resource-rich. Furthermore, due to its inherent 3-D lithium-ion diffusion channels, spinel lithium manganese oxide electrode material exhibits fast lithiation and delithiation kinetics, demonstrating excellent rate performance. This material is one of the most promising electrode materials to replace lithium cobalt oxide (LiCoO2) as the next generation of cobalt-free lithium-ion batteries.
[0004] However, existing lithium manganese oxide electrode materials are all composed of micron-sized or larger agglomerates. During charging and discharging, the diffusion paths of lithium ions and electron transport are relatively long, which limits the discharge specific capacity and rate performance of the materials. Furthermore, the internal stress between agglomerated particles can lead to microcracks on the material surface, accelerating the occurrence of surface side reactions and the erosion of the material by the electrolyte, resulting in a rapid decline in the electrochemical performance of the material.
[0005] Therefore, the research on a novel, simple, and easy-to-operate method for modifying lithium manganese oxide electrode materials and the resulting lithium manganese oxide electrode materials is of great significance. Summary of the Invention
[0006] In view of this, the purpose of the present invention is to provide a modified lithium manganese oxide electrode material and a modification method thereof, so as to solve the technical problems of complex surface modification process of existing lithium manganese oxide electrode materials and poor performance of modified lithium manganese oxide electrode materials.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] This invention provides a method for surface modification of lithium manganese oxide electrode materials, comprising the following steps:
[0009] Lithium manganese oxide was mixed with hydrogen peroxide solution to obtain a surface-modified lithium manganese oxide electrode material.
[0010] The concentration of the hydrogen peroxide solution is 0.05–0.15 g / mL; the lithium manganese oxide is spinel-type lithium manganese oxide.
[0011] Preferably, the mass-to-volume ratio of lithium manganese oxide to hydrogen peroxide solution is 1-3 g: 50-150 mL.
[0012] Preferably, the mixing speed is 500-700 rpm, the mixing time is 25-35 min, and the mixing temperature is 18-30℃.
[0013] The present invention also provides a lithium manganese oxide electrode material prepared by the surface modification method of the aforementioned lithium manganese oxide electrode material.
[0014] Preferably, the initial discharge specific capacity of the lithium manganese oxide electrode material is 120-122 mAh / g, and the cycle retention rate is 88-92% after 100 cycles.
[0015] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:
[0016] (1) The surface modification method described in this invention can effectively remove surface impurities of spinel-type lithium manganese oxide without significantly affecting the crystal structure, thereby improving surface smoothness and accelerating the Li... + The diffusion rate; through this surface modification method, the agglomeration of spinel-type lithium manganese oxide particles can be effectively suppressed, thereby effectively suppressing the phenomenon of microcracks on the material surface caused by the internal stress between agglomerated particles; the surface-modified lithium manganese oxide electrode material of this invention has excellent electrochemical performance.
[0017] (2) The surface modification method of the present invention is simple and low in cost, and is suitable for industrial production; moreover, the present invention has low equipment requirements, simple operation, no special requirements for production process, no pollution in production process, and is environmentally friendly. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0019] Figure 1 The XRD patterns of the surface-modified lithium manganese oxide electrode materials obtained in Examples 1-5 and the spinel-type lithium manganese oxide without surface modification as described in Comparative Example 1 are shown.
[0020] Figure 2SEM images of the surface-modified lithium manganese oxide electrode material obtained in Example 1 and the spinel-type lithium manganese oxide without surface modification in Comparative Example 1 are shown. A and B are the spinel-type lithium manganese oxide without surface modification in Comparative Example 1, and C and D are the surface-modified lithium manganese oxide electrode materials obtained in Example 1.
[0021] Figure 3 The graphs show the electrochemical performance of the surface-modified lithium manganese oxide electrode materials obtained in Examples 1-5 and the spinel-type lithium manganese oxide without surface modification as described in Comparative Example 1. Detailed Implementation
[0022] This invention provides a method for surface modification of lithium manganese oxide electrode materials, comprising the following steps:
[0023] Lithium manganese oxide was mixed with hydrogen peroxide solution to obtain a surface-modified lithium manganese oxide electrode material.
[0024] The concentration of the hydrogen peroxide solution is 0.05–0.15 g / mL; the lithium manganese oxide is spinel-type lithium manganese oxide.
[0025] In this invention, the concentration of the hydrogen peroxide solution is preferably 0.06-0.12 g / mL, and more preferably 0.08-0.1 g / mL.
[0026] In this invention, the preferred mass-to-volume ratio of lithium manganese oxide to hydrogen peroxide solution is 1-3 g: 50-150 mL, more preferably 1.5-2.5 g: 80-150 mL, and even more preferably 2 g: 90-100 mL.
[0027] In this invention, the stirring rate is preferably 500-700 rpm, more preferably 550-650 rpm, and even more preferably 580-600 rpm; the mixing time is preferably 25-35 min, more preferably 28-34 min, and even more preferably 30-32 min; and the mixing temperature is preferably 18-30°C, more preferably 20-28°C, and even more preferably 24-26°C.
[0028] In this invention, the mixture is sequentially filtered, washed, and dried.
[0029] In this invention, the filtration is preferably pressure filtration; the washing is sequential washing with water and ethanol, wherein the number of washings with water and ethanol is preferably 3 times independently, and the washing can remove residual hydrogen peroxide on the surface of modified lithium manganese oxide; in the drying, the drying temperature is preferably 50-70°C, more preferably 55-65°C, more preferably 60-64°C, and the drying time is preferably 10-14 hours, more preferably 11-13 hours, and more preferably 12 hours.
[0030] The present invention also provides a lithium manganese oxide electrode material prepared by the surface modification method of the aforementioned lithium manganese oxide electrode material.
[0031] In this invention, the initial discharge specific capacity of the lithium manganese oxide electrode material is 120-122 mAh / g, and the cycle retention rate is 88-92% after 100 cycles.
[0032] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0033] The spinel-type lithium manganese oxide described in Examples 1-5 and Comparative Example 1 of this invention were all produced by Jiangxi Zhili Technology Co., Ltd.
[0034] Example 1
[0035] Take 50 mL of hydrogen peroxide aqueous solution with a concentration of 0.05 g / mL, add 1 g of spinel-type lithium manganese oxide to the hydrogen peroxide aqueous solution while stirring at 600 rpm. After the addition is complete, keep stirring at 600 rpm. After stirring for 30 min, place the obtained product in a vacuum filter and wash it three times each with deionized water and ethanol. Dry the washed product at 60℃ for 12 h to obtain the surface-modified lithium manganese oxide electrode material.
[0036] Example 2
[0037] Take 80 mL of 0.1 g / mL hydrogen peroxide aqueous solution, add 1 g of spinel-type lithium manganese oxide to the hydrogen peroxide aqueous solution while stirring at 600 rpm. After the addition is complete, keep stirring at 600 rpm. After stirring for 30 min, place the obtained product in a vacuum filter and wash it three times each with deionized water and ethanol. Dry the washed product at 60 °C for 12 h to obtain the surface-modified lithium manganese oxide electrode material.
[0038] Example 3
[0039] Take 100 mL of hydrogen peroxide aqueous solution with a concentration of 0.15 g / mL, add 1 g of spinel-type lithium manganese oxide to the hydrogen peroxide aqueous solution while stirring at 600 rpm. After the addition is complete, keep stirring at 600 rpm. After stirring for 30 min, place the obtained product in a vacuum filter and wash it three times each with deionized water and ethanol. Dry the washed product at 60 °C for 12 h to obtain the surface-modified lithium manganese oxide electrode material.
[0040] Example 4
[0041] Take 50 mL of hydrogen peroxide aqueous solution with a concentration of 0.1 g / mL, and add 1 g of spinel-type lithium manganese oxide to the hydrogen peroxide aqueous solution while stirring at 600 rpm. After the addition is complete, keep stirring at 600 rpm. After stirring for 25 min, place the obtained product in a vacuum filter and wash it three times each with deionized water and ethanol. Dry the washed product at 60℃ for 12 h to obtain the surface-modified lithium manganese oxide electrode material.
[0042] Example 5
[0043] Take 50 mL of 0.1 g / mL hydrogen peroxide aqueous solution, add 1 g of spinel-type lithium manganese oxide to the hydrogen peroxide aqueous solution while stirring at 600 rpm. After the addition is complete, keep stirring at 600 rpm. After stirring for 35 min, place the obtained product in a vacuum filter and wash it three times each with deionized water and ethanol. Dry the washed product at 60 °C for 12 h to obtain the surface-modified lithium manganese oxide electrode material.
[0044] Comparative Example 1
[0045] Spinel-type lithium manganese oxide without surface modification treatment.
[0046] The surface-modified lithium manganese oxide electrode materials obtained in Examples 1-5 and the unmodified spinel-type lithium manganese oxide described in Comparative Example 1 were subjected to performance tests.
[0047] (1) The XRD patterns of the surface-modified lithium manganese oxide electrode materials obtained in Examples 1-5 and the unmodified spinel-type lithium manganese oxide described in Comparative Example 1 are as follows: Figure 1 As shown. By Figure 1 As can be seen, the surface-modified lithium manganese oxide electrode materials obtained in Examples 1 to 5 do not have the generation of second-phase impurity peaks. All diffraction peaks correspond one-to-one with the spinel LiMn2O4 standard card (PDF#35-0782) and belong to the Fd-3m space group, which is a standard spinel lithium manganese oxide electrode material.
[0048] (2) SEM images of the surface-modified lithium manganese oxide electrode material obtained in Example 1 and the unmodified spinel-type lithium manganese oxide described in Comparative Example 1 are shown below. Figure 2 As shown. By Figure 2 As can be seen, the surface-modified lithium manganese oxide electrode material obtained in Example 1 exhibits a polyhedral structure of primary particles with a size of 600–1000 nm, and the particle surface is smooth with no impurity particles adhering to it. Furthermore, the agglomeration phenomenon of the lithium manganese oxide electrode material surface-modified by this method is significantly suppressed, and the processing performance of the material is improved.
[0049] (3) Electrochemical performance testing:
[0050] Preparation steps of lithium battery electrode sheets:
[0051] Using N-methylpyrrolidone as a solvent, the electrode material is mixed with conductive carbon black and polyvinylidene fluoride in a mass ratio of 8:1:1 to obtain a slurry. The slurry is then coated onto an aluminum foil, and the aluminum foil coated with the slurry is placed in a vacuum drying oven at 80°C and dried for 12 hours to obtain the lithium battery electrode sheet.
[0052] The surface-modified lithium manganese oxide electrode materials obtained in Examples 1-5 and the unmodified spinel-type lithium manganese oxide described in Comparative Example 1 were used as electrode materials. Following the above-described preparation steps for lithium battery electrode sheets, six sets of lithium battery electrode sheets were obtained. These six sets of lithium battery electrode sheets were then assembled into 2016 coin cells, and the electrochemical performance of the resulting coin cells was tested. The test results are shown in Table 1 and... Figure 3 As shown.
[0053] Table 1 shows the electrochemical performance test results of the surface-modified lithium manganese oxide electrode materials obtained in Examples 1-5 and the unmodified spinel-type lithium manganese oxide described in Comparative Example 1.
[0054]
[0055] The electrochemical performance curves of the surface-modified lithium manganese oxide electrode materials obtained in Examples 1-5 and the unmodified spinel-type lithium manganese oxide described in Comparative Example 1 are shown in the figure below. Figure 3 As shown. Combined with Figure 3 As shown in Table 1, compared with the unmodified spinel-type lithium manganese oxide, the lithium manganese oxide electrode material obtained by the surface modification method of this invention exhibits superior initial discharge specific capacity and cycle retention. Furthermore, after 100 cycles, the discharge specific capacity of the lithium manganese oxide electrode material prepared by this invention does not show a significant decrease compared to the initial discharge specific capacity, demonstrating excellent cycle stability. Therefore, the surface modification method of this invention can significantly improve the electrochemical performance of lithium manganese oxide electrode materials.
[0056] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for surface modification of lithium manganese oxide electrode material, characterized in that, Includes the following steps: Lithium manganese oxide was mixed with hydrogen peroxide solution to obtain a surface-modified lithium manganese oxide electrode material. The concentration of the hydrogen peroxide solution is 0.05~0.15 g / mL; the lithium manganese oxide is spinel-type lithium manganese oxide; The mass-to-volume ratio of lithium manganate to hydrogen peroxide solution is 1~3g:50~150mL; The mixing time is 25-35 minutes, and the mixing temperature is 18-30℃.
2. The surface modification method for lithium manganese oxide electrode material according to claim 1, characterized in that, The mixing speed is 500~700 rpm.