A modified lithium nickel cobalt manganese oxide cathode material, a preparation method and application thereof
By forming a double-layer coating of isoflurane diisocyanate and polyaniline on the surface of lithium nickel cobalt manganese oxide cathode material, the cycle stability and safety issues of lithium nickel cobalt manganese oxide cathode material in lithium batteries are solved, achieving higher energy density and longer cycle life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUILIN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2026-05-19
- Publication Date
- 2026-07-21
Smart Images
Figure CN122436484A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery materials technology, and in particular to a modified lithium nickel cobalt manganese oxide cathode material, its preparation method, and its application. Background Technology
[0002] With the increasing demand for longer driving ranges in electric vehicles and the pursuit of higher performance in consumer electronics, the need for higher energy density batteries is growing, making the demand for high-energy-density batteries extremely urgent. Among known cathode materials, lithium nickel cobalt manganese oxide (LiCO) is considered one of the most promising due to its high specific capacity and low cost. When lithium metal (Li) is paired with LiCO, the energy density of lithium-ion batteries is expected to approach 500 Wh / kg.
[0003] Despite the advantage of high energy density, lithium nickel cobalt manganese oxide cathode materials have two key problems throughout the entire battery lifecycle: performance degradation (manifested as a decrease in capacity and operating voltage, as well as an increase in battery volume and impedance, resulting in poor cycle stability) and safety hazards. Summary of the Invention
[0004] In view of this, the purpose of this invention is to provide a modified lithium nickel cobalt manganese oxide cathode material, its preparation method, and its application. The modified lithium nickel cobalt manganese oxide cathode material provided by this invention can significantly improve the cycle stability of lithium batteries and significantly enhance their safety performance.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: The present invention provides a modified lithium nickel cobalt manganese oxide cathode material, comprising NCM@IPDI and a polyaniline layer coated on the surface of the NCM@IPDI, wherein the NCM@IPDI comprises lithium nickel cobalt manganese oxide cathode material and an isoflurone diisocyanate layer grafted onto the surface of the lithium nickel cobalt manganese oxide cathode material.
[0006] Preferably, the lithium nickel cobalt manganese oxide cathode material includes one or more of the NCM5, NCM6 and NCM8 cathode materials.
[0007] This invention provides a method for preparing the modified lithium nickel cobalt manganese oxide cathode material described above, comprising the following steps: A grafting reaction was carried out by mixing isoflurone diisocyanate, catalyst, first organic solvent and lithium nickel cobalt manganese oxide cathode material to obtain NCM@IPDI; Polyaniline, a second organic solvent, and the NCM@IPDI were mixed and subjected to a coating reaction to obtain the modified lithium nickel cobalt manganese oxide cathode material.
[0008] Preferably, the catalyst comprises one or more of stannous octoate, dibutyltin diacetate, and dibutyltin dilaurate.
[0009] Preferably, the ratio of isoflurane diisocyanate to the first organic solvent is (2~25) g:1 L, the ratio of catalyst to the first organic solvent is (4~120) μg:1 L, and the mass ratio of isoflurane diisocyanate to lithium nickel cobalt manganese oxide cathode material is (0.01~0.1):1.
[0010] Preferably, the grafting reaction is carried out at a temperature of 60-90°C for 1-3 hours.
[0011] Preferably, the mass ratio of polyaniline to NCM@IPDI is (0.005~0.05):1.
[0012] Preferably, the coating reaction is carried out at a temperature of 80-100°C for 1-3 hours.
[0013] This invention provides the application of the modified lithium nickel cobalt manganese oxide cathode material described in the above technical solutions or the modified lithium nickel cobalt manganese oxide cathode material prepared by the above technical solutions in lithium-ion batteries or lithium metal batteries.
[0014] Preferably, the negative electrode of the lithium-ion battery is graphite or silicon, and the negative electrode of the lithium metal battery is metallic lithium or a lithium alloy.
[0015] This invention provides a modified lithium nickel cobalt manganese oxide cathode material, comprising NCM@IPDI and a polyaniline layer coated on the surface of the NCM@IPDI. The NCM@IPDI comprises the lithium nickel cobalt manganese oxide cathode material and an isophorone diisocyanate layer grafted onto the surface of the lithium nickel cobalt manganese oxide cathode material. Compared with the prior art, this invention has the following beneficial effects: The conductive polymer polyaniline (PANI) can effectively improve the cycle stability and rate performance of lithium nickel cobalt manganese oxide (NCM) cathode materials due to its high conductivity, excellent environmental stability, and low cost. However, pure PANI lacks strong interaction with the NCM material surface, making it difficult to form a uniform and dense coating layer, which limits its modification effect. Isophorone diisocyanate (IPDI), as a highly efficient crosslinking agent, can generate strong hydrogen bonds with the -NH- groups of PANI, resulting in the PANI polymer being tightly adsorbed onto the NCM material surface, allowing PANI to uniformly cover the NCM material surface. In addition, IPDI also acts as a "bridge" connecting NCM, limiting the amount of PANI bonding and promoting the formation of a uniform PANI conductive layer on the NCM surface. The IPDI layer and PANI coating layer act as physical barriers to inhibit excessive oxidation and structural collapse of NCM materials under high voltage, and delay oxygen release. The conjugated structure of PANI acts as an electron buffer layer, temporarily storing excess charge during overcharging, avoiding the aggravation of side reactions caused by local current concentration, and reducing the risk of thermal runaway. As a bifunctional crosslinking agent, IPDI connects multiple linear PANI chains to form a three-dimensional network crosslinked structure. The PANI network after IPDI crosslinking has good elasticity and extensibility, and can maintain the coating of NCM particles under the severe thermal shock and mechanical stress caused by short circuit, preventing the internal short circuit caused by particle breakage from further expanding. At the same time, its efficient thermal conductivity can quickly diffuse the local hot spots generated by short circuit, avoid thermal runaway caused by heat accumulation, and improve the safety of the battery under short circuit abuse conditions.
[0016] This invention employs a strategy of progressively coating NCM materials with IPDI and PANI, which can achieve uniform and stable modification of NCM materials. This effectively suppresses side reactions between the cathode material and the electrolyte, reduces the dissolution of metal ions, improves electron transport efficiency, fundamentally enhances the energy density and cycle life of lithium batteries, and significantly improves their safety performance under abuse conditions such as overcharging, overheating, and short circuits. Attached Figure Description
[0017] Figure 1 XRD patterns of the original NCM523 cathode material (Pristine NCM523), NCM523@IPDI, and NCM523@IPDI@PANI; Figure 2 Cycle performance diagrams for NCM523, NCM523@IPDI, and NCM523@IPDI@PANI cathode materials; Figure 3 SEM image of NCM622@IPDI@PANI cathode material; Figure 4 Cycle performance diagrams for NCM622, NCM622@IPDI, and NCM622@IPDI@PANI cathode materials; Figure 5 Cyclic voltammetry curves of the original NCM811 cathode material (Pristine NCM811) and the modified NCM811 cathode material (NCM811@IPDI@PANI); Figure 6 The graph shows the cycle performance of NCM811, NCM811@IPDI, and NCM811@IPDI@PANI cathode materials. Detailed Implementation
[0018] The present invention provides a modified lithium nickel cobalt manganese oxide cathode material, comprising NCM@IPDI and a polyaniline (PANI) layer coated on the surface of the NCM@IPDI, wherein the NCM@IPDI comprises lithium nickel cobalt manganese oxide cathode material (NCM) and an isoflurane diisocyanate (IPDI) layer grafted onto the surface of the lithium nickel cobalt manganese oxide cathode material.
[0019] In this invention, the lithium nickel cobalt manganese oxide cathode material preferably includes one or more of NCM5, NCM6 and NCM8 cathode materials. Specifically, the NCM5 cathode material can be NCM523, the NCM6 cathode material can be NCM622, and the NCM8 cathode material can be NCM811.
[0020] In this invention, the modified lithium nickel cobalt manganese oxide cathode material is referred to as NCM@IPDI@PANI.
[0021] The modified nickel-cobalt-manganese lithium cathode material provided by this invention has a dual protective layer of organic small molecules (i.e., isoflurane diisocyanate) and conductive polymer (i.e., polyaniline), which can effectively suppress the side reactions between the cathode material and the electrolyte, reduce the dissolution of metal ions, improve electron transport efficiency, and significantly improve the stability of the nickel-cobalt-manganese ternary cathode material.
[0022] This invention provides a method for preparing the modified lithium nickel cobalt manganese oxide cathode material described above, comprising the following steps: A grafting reaction was carried out by mixing isoflurone diisocyanate, catalyst, first organic solvent and lithium nickel cobalt manganese oxide cathode material to obtain NCM@IPDI; Polyaniline, a second organic solvent, and the NCM@IPDI were mixed and subjected to a coating reaction to obtain the modified lithium nickel cobalt manganese oxide cathode material.
[0023] Unless otherwise specified, all raw materials involved in this invention are commercially available products well known in the art.
[0024] This invention involves a grafting reaction of isoflurane diisocyanate, catalyst, first organic solvent and lithium nickel cobalt manganese oxide cathode material to obtain NCM@IPDI.
[0025] In this invention, the lithium nickel cobalt manganese oxide cathode material is the same as the above-described technical solution, and will not be repeated here. In this invention, the catalyst preferably includes one or more of stannous octoate, dibutyltin diacetate, and dibutyltin dilaurate; the first organic solvent can be N-methylpyrrolidone (NMP). In this invention, the preferred ratio of isoflurane diisocyanate to the first organic solvent is (2~25) g:1 L, which can be (5~20) g:1 L, specifically 9 g:1 L, 10 g:1 L, or 19 g:1 L; the preferred ratio of the catalyst to the first organic solvent is (4~120) μg:1 L. In this invention, the preferred mass ratio of isoflurane diisocyanate to lithium nickel cobalt manganese oxide cathode material is (0.01~0.1):1, which can be 0.04:1, 0.05:1 or 0.09:1. Controlling the mass ratio of isoflurane diisocyanate to lithium nickel cobalt manganese oxide cathode material within the above range is beneficial to improving the capacity retention rate and rate performance of the material.
[0026] In an embodiment of the present invention, the preferred method for mixing isoflurane diisocyanate, catalyst, first organic solvent and lithium nickel cobalt manganese oxide cathode material is as follows: in a glove box, isoflurane diisocyanate is added to the first organic solvent, then the catalyst is added, the resulting mixture is stirred evenly, and then lithium nickel cobalt manganese oxide cathode material is added to it.
[0027] In this invention, the grafting reaction temperature is preferably 60-90°C, which can be 60, 70, 80, or 90°C, and the time is preferably 1-3 hours, which can be 1, 2, or 3 hours; the grafting reaction is preferably carried out under stirring conditions. During the grafting reaction, the hydroxyl groups on the surface of the lithium nickel cobalt manganese oxide cathode material bond with the highly reactive NCO groups in isoflurane diisocyanate, thus covalently anchoring the isoflurane diisocyanate to the surface of the lithium nickel cobalt manganese oxide cathode material. This invention uses isoflurane diisocyanate, which has an asymmetric alicyclic structure. The two NCO groups have different activities. The highly reactive NCO bonds preferentially react with the hydroxyl groups on the surface of the lithium nickel cobalt manganese oxide cathode material, and the remaining less reactive NCOs can then slowly bond with polyaniline. Compared with other diisocyanates, isoflurane diisocyanate can be covalently bonded stepwise, its activity is controllable, and the thickness of the coating layer is easily controlled.
[0028] After the grafting reaction is completed, the present invention preferably cools the resulting reaction solution to room temperature, and then performs centrifugation, washing and vacuum drying in sequence to obtain NCM@IPDI.
[0029] After obtaining NCM@IPDI, the present invention mixes polyaniline, a second organic solvent and the NCM@IPDI to carry out a coating reaction to obtain the modified lithium nickel cobalt manganese oxide cathode material.
[0030] This invention does not have any special requirements for the polyaniline used; any polyaniline well-known to those skilled in the art can be used. In this embodiment, the polyaniline was purchased from Aladdin, catalog number P169039. In this invention, the second organic solvent can be N-methylpyrrolidone (NMP). This invention does not have any special requirements for the amount of the second organic solvent used, as long as it is sufficient to completely dissolve the polyaniline. In this invention, the preferred mass ratio of polyaniline to NCM@IPDI is (0.005~0.05):1, which can be 0.005:1, 0.01:1, 0.02:1, 0.03:1, 0.04:1, or 0.05:1. Controlling the mass ratio of polyaniline to NCM@IPDI within the above range in this invention is beneficial for improving the initial capacity and cycle performance of the material.
[0031] In this embodiment of the invention, the preferred method for mixing polyaniline, the second organic solvent, and NCM@IPDI is as follows: in a glove box, polyaniline is added to the second organic solvent and stirred to form a uniform solution, and then NCM@IPDI is added to it.
[0032] In this invention, the coating reaction temperature is preferably 80~100℃, which can be 80, 90 or 100℃, and the time is preferably 1~3h, which can be 1, 2 or 3h; the coating reaction is preferably carried out under stirring conditions. In this invention, the coating reaction specifically involves: firstly, the strong hydrogen bonding between the -NCO bond reserved in isophorone diisocyanate and the -NH2 group of polyaniline causes polyaniline to be tightly adsorbed onto the surface of the lithium nickel cobalt manganese oxide cathode material, thereby uniformly covering the surface of the lithium nickel cobalt manganese oxide cathode material with polyaniline. After isophorone diisocyanate bonds with polyaniline, the imine nitrogen in the polyaniline on the surface undergoes a cross-linking reaction, and a uniform polyaniline layer is easily formed on the outside of the polyaniline polymer.
[0033] After the coating reaction is completed, the present invention preferably cools the resulting reaction solution to room temperature, and then performs centrifugal washing and vacuum drying in sequence to obtain the modified nickel cobalt manganese oxide cathode material (NCM@IPDI@PANI); the centrifugal washing is sufficient to effectively remove impurities from the material surface, and the present invention does not have special requirements for the temperature and time of the vacuum drying, as long as the material reaches a completely dry state.
[0034] This invention focuses on lithium nickel cobalt manganese oxide cathode material, selecting isophorone diisocyanate (IPDI) and polyaniline (PANI), and through a simple heating and stirring process, a uniform IPDI and PANI double coating layer is sequentially formed on the surface of the lithium nickel cobalt manganese oxide cathode material.
[0035] This invention provides the application of the modified lithium nickel cobalt manganese oxide cathode material described in the above technical solutions or the modified lithium nickel cobalt manganese oxide cathode material prepared by the above technical solutions in lithium-ion batteries or lithium metal batteries.
[0036] In this invention, the negative electrode of the lithium-ion battery is preferably graphite or silicon, and the negative electrode of the lithium metal battery is preferably metallic lithium or a lithium alloy. This invention does not impose special requirements on the assembly of the lithium-ion battery or lithium metal battery, the loading of the positive electrode material, the type of electrolyte, or the amount of electrolyte added, as long as the battery can operate normally.
[0037] In this invention, the modified lithium nickel cobalt manganese oxide cathode material is applied to lithium-ion batteries or lithium metal batteries, resulting in lithium batteries with higher energy density and longer cycle life.
[0038] To further illustrate the present invention, the modified lithium nickel cobalt manganese oxide cathode material, its preparation method, and its application are described in detail below with reference to examples, but these should not be construed as limiting the scope of protection of the present invention.
[0039] In the examples, polyaniline was purchased from Aladdin, catalog number P169039.
[0040] Example 1 A modified lithium nickel cobalt manganese oxide cathode material (NCM523@IPDI@PANI) is prepared by the following steps: (1) In a glove box, isoflurane diisocyanate (IPDI) was added to N-methylpyrrolidone (NMP) to a concentration of 19 g / L, and then stannous octoate was added to a concentration of 106 μg / L. The above mixture was stirred until it was completely homogeneous, and then NCM523 cathode material was added to make the mass ratio of IPDI to NCM523 0.09:1. Then, the mixture was heated to 80°C for 3 h under stirring. After the reaction was completed, it was cooled to room temperature, the mixture was removed, centrifuged and washed, and then vacuum dried to obtain NCM523@IPDI.
[0041] (2) In a glove box, polyaniline (PANI) was added to N-methylpyrrolidone (NMP) to dissolve and form a homogeneous solution (2.5 mg / mL); then the NCM523@IPDI intermediate prepared in step (1) was added, and the mass ratio of PANI to NCM523@IPDI was controlled to be 0.005:1; then the mixture was heated to 100°C for 2 h under stirring. After the reaction was completed, it was naturally cooled to room temperature. The mixture was taken out, centrifuged and washed, and then vacuum dried to obtain the reaction product NCM523@IPDI@PANI.
[0042] (3) The NCM523@IPDI and NCM523@IPDI@PANI positive electrode materials obtained in steps (1) and (2) are prepared into electrode sheets and assembled into a battery with a lithium metal negative electrode. The electrolyte is a mixture of 1 M LiPF6 dissolved in dimethyl carbonate (DMC), ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (1:1:1 v / v).
[0043] Figure 1 The XRD patterns are of the original NCM523 cathode material (Pristine NCM523), NCM523@IPDI, and NCM523@IPDI@PANI. Figure 1 The XRD patterns showed that the key characteristics of the NCM523 cathode material, such as peak position, peak intensity, and peak shape, did not change significantly after being modified with isoflurane diisocyanate (IPDI) alone or with a combination of isoflurane diisocyanate (IPDI) and polyaniline (PANI). This result indicates that the applied surface coating did not affect the original layered crystal structure of the NCM523 cathode material.
[0044] Cyclic performance tests were conducted on the original NCM523 cathode material (NCM523), NCM523@IPDI, and NCM523@IPDI@PANI cathode materials. The test conditions were set as follows: voltage range 2.8–4.3V, temperature 28℃, and charge / discharge rate of 1C (1C = 170 mAh / g). The test results are shown below. Figure 2 , Figure 2 The cycling performance diagrams are for NCM523, NCM523@IPDI, and NCM523@IPDI@PANI. Figure 2 Test results show that the cycling stability of the three cathode materials differed significantly throughout the cycling process, directly reflecting the progressive optimization path of the material coating strategy. Specifically, the NCM523@IPDI@PANI cathode material exhibited more stable cycling performance, with a capacity retention of 87.17% after 100 cycles; the NCM523@IPDI cathode material retained 81.50% of its capacity; while the original NCM523 cathode material only retained 57.80%. This significant improvement in cycling stability is attributed to the dual protection provided by IPDI and PANI to the NCM523 cathode material.
[0045] Example 2 A modified lithium nickel cobalt manganese oxide cathode material (NCM622@IPDI@PANI) is prepared by the following steps: (1) In a glove box, isoflurane diisocyanate (IPDI) was added to N-methylpyrrolidone (NMP) to a concentration of 10 g / L, and then dibutyltin diacetate was added to a concentration of 53 μg / L. The above mixture was stirred until it was completely homogeneous, and then NCM622 cathode material was added to make the mass ratio of IPDI to NCM622 0.05:1. Then, the mixture was heated to 80 °C for 3 h under stirring. After the reaction was completed, it was cooled to room temperature, the mixture was removed, centrifuged and washed, and then vacuum dried to obtain NCM622@IPDI.
[0046] (2) In a glove box, polyaniline (PANI) was added to N-methylpyrrolidone (NMP) to dissolve and form a homogeneous solution (2.5 mg / mL). Then, the NCM622@IPDI intermediate prepared in step (1) was added, and the mass ratio of PANI to NCM622@IPDI was controlled to be 0.01:1. Then, the mixture was heated to 100°C for 2 h under stirring. After the reaction was completed, it was naturally cooled to room temperature. The mixture was removed, centrifuged and washed, and then vacuum dried to obtain the reaction product NCM622@IPDI@PANI.
[0047] (3) The NCM622@IPDI and NCM622@IPDI@PANI positive electrode materials obtained in steps (1) and (2) are used to prepare electrode sheets and assembled into a battery with a lithium metal negative electrode. The electrolyte is a mixture of 1 M LiPF6 dissolved in dimethyl carbonate (DMC), ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (1:1:1 v / v).
[0048] The morphology of the NCM622@IPDI@PANI cathode material was characterized, such as... Figure 3 As shown, Figure 3 SEM images of the NCM622@IPDI@PANI cathode material. Figure 3 As can be seen, the NCM622 particles, after joint surface modification with isoflurane diisocyanate (IPDI) and polyaniline (PANI), have a dense and smooth protective layer on their surface. The presence of this protective layer effectively reduces the direct contact between the cathode material and the electrolyte, suppressing potential side reactions. Furthermore, it significantly enhances the electronic conductivity of the cathode material, contributing to improved overall electrochemical performance of the battery.
[0049] Cyclic performance tests were conducted on the original NCM622 cathode material (NCM622), NCM622@IPDI, and NCM622@IPDI@PANI cathode materials. The test conditions were set as follows: voltage range 2.8~4.3V, temperature 28℃, and charge / discharge rate of 1C (1C=180mAh / g). The results are as follows: Figure 4As shown in the figure, the test results indicate that the cycling stability of the three cathode materials differed significantly throughout the entire cycle, directly reflecting the progressive optimization path of the material coating strategy. Specifically, the NCM622@IPDI@PANI cathode material exhibited more stable cycling performance, with a capacity retention of up to 90.10% after 100 cycles; the NCM622@IPDI cathode material had a capacity retention of 87.17%; while the original NCM622 cathode material had a capacity retention of only 66.12%. This significant improvement in cycling stability is attributed to the dual protection of the NCM811 cathode material by IPDI and PANI.
[0050] Example 3 A modified lithium nickel cobalt manganese oxide cathode material (NCM811@IPDI@PANI) is prepared by the following steps: (1) In a glove box, isoflurane diisocyanate (IPDI) was added to N-methylpyrrolidone (NMP) to a concentration of 9 g / L, and then dibutyltin dilaurate catalyst was added to a concentration of 53 μg / L. The above mixture was stirred until completely homogeneous, and then NCM811 cathode material was added to make the mass ratio of IPDI to NCM811 0.04:1. The mixture was then heated to 80 °C for 3 h under stirring. After the reaction was completed, it was cooled to room temperature, the mixture was removed, centrifuged and washed, and then vacuum dried to obtain NCM811@IPDI.
[0051] (2) In a glove box, polyaniline (PANI) was added to N-methylpyrrolidone (NMP) to dissolve and form a homogeneous solution (2.5 mg / mL). Then, the NCM811@IPDI intermediate prepared in step (1) was added, and the mass ratio of PANI to NCM811@IPDI was controlled to be 0.02:1. Then, the mixture was heated to 100°C for 2 h under stirring. After the reaction was completed, it was naturally cooled to room temperature. The mixture was removed, centrifuged and washed, and then vacuum dried to obtain the reaction product NCM811@IPDI@PANI.
[0052] (3) The NCM811@IPDI and NCM811@IPDI@PANI positive electrode materials obtained in steps (1) and (2) are used to prepare electrode sheets and assembled with lithium metal negative electrodes to form a battery. The electrolyte is a mixture of 1 M LiPF6 dissolved in dimethyl carbonate (DMC), ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (1:1:1 v / v).
[0053] Within a voltage range of 2.8 to 4.3 V, at a rate of 0.1 mV·s -1 Cyclic voltammetry tests were performed on NCM811 and NCM811@IPDI@PANI cathode materials at a scan rate of [missing information]. Figure 5 A comparison of the cyclic voltammetry curves shows that ( Figure 5 The figures show the cyclic voltammetry curves of the original NCM811 cathode material (Pristine NCM811) and the modified NCM811 cathode material (NCM811@IPDI@PANI). The significant reduction in the peak potential difference of the NCM811@IPDI@PANI cathode material indicates a marked improvement in its reversibility. Furthermore, throughout the entire voltage scan range, the current response of the NCM811@IPDI@PANI cathode material is generally higher than that of the NCM811 material. This means that the modified cathode material can provide a larger current under the same voltage conditions, demonstrating higher electrochemical activity and superior ion / electron conduction performance.
[0054] Cyclic performance tests were conducted on NCM811, NCM811@IPDI, and NCM811@IPDI@PANI cathode materials. Test conditions were set at a voltage range of 2.8–4.3 V, a temperature of 28 °C, and a charge / discharge rate of 1C (1C = 200 mAh / g). The test results are shown below. Figure 6 , Figure 6 The graphs show the cycling performance of NCM811, NCM811@IPDI, and NCM811@IPDI@PANI cathode materials. The test results indicate that the cycling stability of the three cathode materials differs significantly throughout the cycling process, directly reflecting the progressive optimization path of the material coating strategy. Specifically, the NCM811@IPDI@PANI cathode material exhibits more stable cycling performance, with a capacity retention of 93.40% after 100 cycles; the NCM811@IPDI cathode material retains 85.04% of its capacity; while the original NCM811 cathode material retains only 72.31%. This significant improvement in cycling stability is attributed to the dual protection provided by IPDI and PANI to the NCM811 cathode material.
[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles 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 modified lithium nickel cobalt manganese oxide cathode material, characterized in that, It includes NCM@IPDI and a polyaniline layer covering the surface of the NCM@IPDI, wherein the NCM@IPDI includes lithium nickel cobalt manganese oxide cathode material and an isoflurane diisocyanate layer grafted onto the surface of the lithium nickel cobalt manganese oxide cathode material.
2. The modified lithium nickel cobalt manganese oxide cathode material according to claim 1, characterized in that, The lithium nickel cobalt manganese oxide cathode material includes one or more of the NCM5, NCM6 and NCM8 series cathode materials.
3. The method for preparing the modified lithium nickel cobalt manganese oxide cathode material according to claim 1 or 2, characterized in that, Includes the following steps: A grafting reaction was carried out by mixing isoflurone diisocyanate, catalyst, first organic solvent and lithium nickel cobalt manganese oxide cathode material to obtain NCM@IPDI; Polyaniline, a second organic solvent, and the NCM@IPDI were mixed and subjected to a coating reaction to obtain the modified lithium nickel cobalt manganese oxide cathode material.
4. The preparation method according to claim 3, characterized in that, The catalyst includes one or more of stannous octoate, dibutyltin diacetate, and dibutyltin dilaurate.
5. The preparation method according to claim 3 or 4, characterized in that, The ratio of isoflurane diisocyanate to the first organic solvent is (2~25) g:1 L, the ratio of catalyst to the first organic solvent is (4~120) μg:1 L, and the mass ratio of isoflurane diisocyanate to lithium nickel cobalt manganese oxide cathode material is (0.01~0.1):
1.
6. The preparation method according to claim 3, characterized in that, The grafting reaction is carried out at a temperature of 60-90°C for 1-3 hours.
7. The preparation method according to claim 3, characterized in that, The mass ratio of polyaniline to NCM@IPDI is (0.005~0.05):
1.
8. The preparation method according to claim 3 or 7, characterized in that, The coating reaction is carried out at a temperature of 80-100℃ for 1-3 hours.
9. The application of the modified lithium nickel cobalt manganese oxide cathode material according to claim 1 or 2, or the modified lithium nickel cobalt manganese oxide cathode material prepared by the preparation method according to any one of claims 3 to 8, in lithium-ion batteries or lithium metal batteries.
10. The application according to claim 9, characterized in that, The negative electrode of the lithium-ion battery is graphite or silicon, and the negative electrode of the lithium metal battery is metallic lithium or a lithium alloy.