Preparation method for synergistically modifying ternary positive electrode material by utilizing double-element doping
By modifying ternary cathode materials with nano-WO3 and NdN3O9·6H2O dual-element doping, the problem of structural instability under high voltage was solved, and excellent electrochemical performance of high-energy-density lithium-ion batteries was achieved, especially in terms of stability and high capacity performance over high voltage and wide temperature range.
Patent Information
- Application Number
- CN202510848774.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-11-11
AI Technical Summary
Existing ternary cathode materials are structurally unstable under high voltage, exhibiting problems such as microcracks and lattice oxygen extraction. The effect of single-element doping modification is limited, making it difficult to meet the requirements of high-energy-density lithium-ion batteries.
A method for preparing ternary cathode materials using dual-element doping of nano-WO3 and NdN3O9·6H2O was adopted. Through high-temperature sintering, strong metallic bonds between Nd-O and WO were formed, lattice oxygen was stabilized, electronic conductivity was improved, and microcrack formation was suppressed through columnar effect.
It achieves excellent cycle performance and rate performance of ternary cathode materials under high voltage, has higher operating voltage and discharge specific capacity, and can operate stably over a wide temperature range.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium-ion battery cathode material preparation, specifically to the modification of nickel-cobalt-manganese ternary cathode materials. Background Technology
[0002] Compared to traditional fossil fuels, lithium-ion batteries offer advantages such as high specific capacity, high energy density, long cycle life, and environmental friendliness, making them considered the most suitable energy storage device currently available. With the rapid development of the new energy vehicle sector, higher energy density requirements are being placed on lithium-ion batteries, and high-capacity cathode materials play a crucial role in the electrochemical performance of lithium-ion batteries. Ternary layered oxides LiNi x Co y Mn z O2 (NCM, x + y + z = 1) has become a promising candidate cathode for lithium-ion batteries due to its competitive advantages such as high specific capacity and relatively high operating voltage. In order to further improve the energy density of ternary cathode materials, research has not only focused on increasing the nickel content of NCM cathodes, but also on further improving the operating voltage (≥4.5V) of LIBs.
[0003] Ternary cathode materials also present some problems under high voltage. High operating voltage accelerates the decomposition of the organic electrolyte, and the byproducts of this decomposition lead to undesirable side reactions at the interface with the cathode active material, further deteriorating the structural stability of the NCM cathode. Simultaneously, performance degradation problems existing under conventional voltages become more pronounced at high voltages, such as structural degradation, microcracks, and lattice oxygen extraction. Current modification strategies for addressing these problems mainly include doping and coating. Previous studies have used Al doping technology to modify LiNi... 0.8 Co 0.1 Mn 0.1 O2 was used to study Al doping modification, and it was found that Al and O can form stronger Al-O bonds, thereby effectively improving the structural strength of the material (Journal of The Electrochemical Society, 2020, 167(2): 020522). Cheng Jianli's team studied in detail the effect of single different ion doping on the performance of ternary cathode materials (Journal of Materials Chemistry A, 2020, 8(44):23293-23303). The doping sites and surface stability of the elements in the layered materials were calculated using first-principles calculations. The results showed that high-valence elements have stronger MO bonds, which are beneficial to the stability of the structure. At the same time, these elements are more likely to segregate to the surface layer.
[0004] While single-element doping has some effect on the modification of ternary cathode materials, its ability to suppress performance degradation under high voltage is limited. Therefore, it is necessary to explore new modification strategies from multiple perspectives to improve the structural stability and electrochemical performance of ternary cathode materials under high voltage, thereby obtaining lithium-ion power batteries with higher energy density. Summary of the Invention
[0005] In view of this, the purpose of this invention is to provide a low-cost, simple, and high-performance modification method for ternary cathode materials, so as to achieve excellent cycle performance and rate performance of ternary cathode materials under high voltage.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing ternary cathode materials using dual-element doping synergistic modification, comprising the following steps: 1) Weigh nano WO3 and NdN3O9·6H2O according to a certain molar ratio, add them to a certain amount of anhydrous ethanol, and stir vigorously to obtain a mixed solution L1. 2) Weigh a certain amount of ternary cathode material precursor, pour it into L1 solution and continue stirring. After stirring for a certain period of time, transfer it to a heated stirring table until the slurry is dried to obtain precursor powder. 3) The precursor powder was mixed and ground with a certain proportion of LiOH·H2O and sintered at high temperature to obtain a ternary cathode material with dual-element synergistic modification.
[0007] Preferably, the optimal addition amounts of nano WO3 and NdN3O9·6H2O are 0~1% and 0~1% (molar ratio) of the ternary cathode material precursor, respectively.
[0008] Preferably, the volume of anhydrous ethanol is 30 ml, and the stirring time is 1 h.
[0009] Preferably, the heating stirrer is set to a temperature of 60°C and a rotation speed of 400 r / min.
[0010] Preferably, the sintering process includes a first sintering stage and a second sintering stage performed sequentially. The temperature of the first sintering stage is 500°C and the time of the first sintering stage is 5 hours. The temperature of the second sintering stage is 850°C and the time of the second sintering stage is 12 hours. The sintering atmosphere is oxygen.
[0011] Preferably, the chemical formula of the modified ternary cathode material can be represented as Li(Ni) 0.80 Co 0.10 Mn 0.10 ) 1-x- y O2Wx Nd y , where 0≤x≤0.01, 0≤y≤0.01.
[0012] The present invention has the following beneficial effects: 1. The key feature of this invention is the synergistic modification effect of "1+1>2" achieved through multi-element doping. The "columnar effect" of W induces the primary particles to pack tightly along the radial direction, effectively suppressing the formation of microcracks during long-term cycling; Nd introduces additional electronic defects, increasing the electronic conductivity of the material, and the modified cathode material still exhibits excellent electrochemical performance at low temperatures. Furthermore, Nd-O and WO bonds stabilize the lattice oxygen through strong metallic bonding; 2. Compared with other modification methods, the raw materials are inexpensive and readily available, and the preparation process is simple. It is prepared by solid-state reaction supplemented by sintering process. 3. The ternary cathode material prepared by the method described in this invention has a higher operating voltage, high discharge specific capacity, excellent cycle performance and rate performance at 2.5-4.5 and 4.7V, and can still operate stably at high capacity at -20℃ and 60℃. Attached Figure Description
[0013] Figure 1 This is a SEM image of the ternary polycrystalline cathode material prepared in Comparative Example 1.
[0014] Figure 2 This is a SEM image of the modified ternary polycrystalline cathode material prepared in Example 1.
[0015] Figure 3 This is a rate performance diagram of a coin cell prepared with modified ternary cathode material.
[0016] Figure 4 This is a cycle diagram of coin cells prepared with modified ternary cathode materials at 2.5-4.7V, 25℃, and 1C.
[0017] Figure 5 This is a cycle diagram of preparing modified ternary cathode material coin cells at 2.5-4.5V, 60℃, and 1C.
[0018] Figure 6 This is a cycle diagram of a coin cell prepared with modified ternary cathode material at 2.5-4.5V, -20℃, and 0.2C.
Claims
1. A method for preparing ternary cathode materials using dual-element doping synergistic modification, characterized in that, The method includes the following steps: 1) Weigh different metal compounds according to a certain molar ratio, add them to a certain amount of anhydrous ethanol, and stir vigorously to obtain a mixed solution L1; 2) Weigh a certain amount of ternary cathode material precursor, pour it into L1 solution and continue stirring. After stirring for a certain period of time, transfer it to a heated stirring table until the slurry is dried to obtain precursor powder. 3) The precursor powder was mixed and ground with a certain proportion of LiOH·H2O and sintered at high temperature to obtain a ternary cathode material with dual-element synergistic modification.
2. Among them, The metal element compound is preferably at the nanoscale or is an easily decomposable material, preferably WO3 and NdN3O9·6H2O.
3. According to the preparation method described in claim 1, the optimal addition amounts of nano WO3 and NdN3O9·6H2O are 0~1% and 0~1% (molar ratio) of the ternary cathode material precursor, respectively.
4. The preparation method according to claim 1, characterized in that, In step 1), nano-WO3 and NdN3O9·6H2O are uniformly dispersed in anhydrous ethanol at a certain stoichiometric ratio. The volume of anhydrous ethanol is 30 ml, and the stirring time is 1 h.
5. The preparation method according to claim 1, characterized in that, After adding the ternary cathode material precursor in step 2), continue stirring vigorously for 1 hour, then transfer it to a heated stirrer. The temperature of the heated stirrer is set to 60℃ and the speed is 400r / min.
6. The preparation method according to claim 1, characterized in that, The high-temperature sintering process in step 3) includes a first stage sintering and a second stage sintering performed sequentially. The temperature of the first stage sintering is 500℃ and the sintering time of the first stage is 5h. The temperature of the second stage sintering is 850℃ and the sintering time of the second stage is 12h. The sintering atmosphere is oxygen.