A fast-charging layered lithium-rich cathode material, a preparation method and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGDAO UNIV
- Filing Date
- 2026-03-11
- Publication Date
- 2026-05-29
Smart Images
Figure CN122117885A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium-ion battery cathode material technology, and more specifically, to a fast-charging layered lithium-rich cathode material, its preparation method, and its application. Background Technology
[0002] High-capacity, high-voltage cathode materials are crucial for improving the energy density of lithium-ion batteries and achieving fast charging. Among numerous candidate materials, lithium-rich manganese-based materials with layered structures (xLi2MnO3·(1-x)LiMO2) and lithium-rich ruthenium-based materials (such as Li2RuO3 and its derivatives) have attracted much attention due to their reversible capacity (>250 mAh / g) far exceeding that of traditional lithium cobalt oxide or ternary materials. Among them, lithium-rich ruthenium-based material Li2RuO3 is considered a highly promising system for achieving both high energy density and high power density due to its unique anionic redox activity and relatively better structural stability and electronic conductivity. However, pure-phase Li2RuO3 is expensive, and during deep delithiation (corresponding to the end of high-rate charging), it still faces the problem of irreversible precipitation of lattice oxygen and structural relaxation, leading to capacity decay and voltage hysteresis, which seriously restricts its cycle stability at ultra-high rates (such as >5C). The core challenge for this material to move towards fast-charging applications is how to further stabilize its structure without sacrificing its advantages of high capacity and high conductivity.
[0003] While techniques such as nanostructuring and carbon coating can generally improve the rate performance of electrode materials, these methods have significant limitations for lithium-rich ruthenium-based materials. For example, while nanostructuring can shorten the lithium-ion diffusion path, it significantly increases the specific surface area, exacerbates interfacial side reactions, and reduces tap density and volumetric energy density. Furthermore, conventional carbon coatings may hinder the rapid transport of lithium ions at ultra-high rates.
[0004] Bulk doping is a classic strategy for improving the performance of lithium-rich materials. For the Li₂RuO₃ system, previous studies have attempted to introduce other elements to stabilize the lattice. For example, partially replacing Ru with Sn in Li₂RuO₃ effectively suppressed oxygen loss and improved cycle stability. However, this research mainly focused on capacity retention under long cycles and did not systematically evaluate or report its fast-charging performance at extremely high rates (such as 10C). Furthermore, the introduction of elements such as Sn has limited effect on improving the intrinsic electronic and ionic conductivity of the material, making it difficult to meet the ultrafast lithium-ion diffusion kinetics required for 10C fast charging. Summary of the Invention
[0005] To address the problems existing in the prior art, this invention provides a fast-charging layered lithium-rich cathode material, its preparation method, and its applications. This invention aims to solve the problem of sluggish lithium-ion diffusion kinetics in high-energy-density layered lithium battery cathode materials during ultra-high rate (e.g., 10C) charging. Through an innovative doping design, while ensuring the stability of the material structure, its intrinsic ion diffusion rate is greatly improved, thereby obtaining a cathode material with both high capacity and excellent 10C fast-charging performance. Specifically, this invention focuses on the following technical path: a preparation method using specific Ti element doping to modify Li2RuO3, utilizing the strong Ti-O bond to stabilize the crystal structure and suppress oxygen evolution. More importantly, through precise control of the doping process, the two-dimensional diffusion channels of lithium ions are optimized and activated, significantly reducing the lithium-ion migration barrier, thus fundamentally solving the kinetic obstacle of fast charging. The prepared material exhibits a charging capacity retention rate far exceeding that of conventional modified Li2RuO3 materials under 10C (6 minutes) ultra-high rate charging conditions. While achieving 10C fast charging, the material maintains a high reversible specific capacity and exhibits excellent capacity retention and structural integrity in long-term high-rate cycling tests, overcoming the problem that fast charging typically accelerates material degradation. This design solves a long-standing bottleneck in fast-charging dynamics that has remained unresolved in existing technologies, providing a key material solution for the development of next-generation fast-charging high-energy-density batteries.
[0006] This application utilizes Ti to equivalently dissolve and substitute Ru in Li₂RuO₃, which enhances the stability of the oxygen framework and suppresses lattice oxygen loss during high-voltage charge-discharge processes by leveraging the strong Ti–O bond. Simultaneously, Ti doping can also modulate interlayer spacing and local structure, constructing two-dimensional Li₂ with lower energy barriers. + Diffusion Channel. Unlike existing technologies that focus on structural stability and cycle life improvement at low to medium rates, this invention further addresses the kinetic bottleneck at the end of a 10C (approximately 6 min) ultra-high rate fast charge under a high cutoff voltage of 4.6 V. It proposes a synergistic design of "doping amount window + sintering-controlled cooling regime" to simultaneously enhance structural stability and fast charging kinetics. Without sacrificing high reversible capacity, it achieves high capacity retention and long-term cycle stability of the Li2RuO3-based lithium-rich cathode under 10C ultra-high rate conditions.
[0007] To achieve the above objectives, the present invention provides the following technical solution:
[0008] One objective of this application is to provide a fast-charging layered lithium-rich cathode material, wherein the cathode material is a Ti-doped lithium ruthenium oxide material with the general chemical formula Li₂Ru. 1-x Ti xO3, wherein 0.01 < x ≤ 0.25, preferably 0.03 ≤ x ≤ 0.12, more preferably 0.04 ≤ x ≤ 0.08, for example, x values are 0.01, 0.03, 0.04, 0.05, 0.08, 0.1, 0.12, 0.25.
[0009] In a preferred embodiment, Ti is uniformly distributed in the layered crystal structure of lithium ruthenium oxide in the form of a solid solution, forming a stable Li₂Ru. 1-x Ti x O3 single-phase structure.
[0010] Preferably, the cathode material has an initial discharge specific capacity of ≥150 mAh / g at 10C rate; and / or, after 100 cycles at 10C rate and room temperature of 2–4.6 V, the capacity retention is ≥80%.
[0011] In a preferred embodiment, the cathode material has a submicron-scale polyhedral particle morphology, with a typical particle size on the order of hundreds of nanometers; and the Ru, Ti and O in the cathode material are uniformly distributed within the particles.
[0012] The second objective of this application is to provide a method for preparing the fast-charging layered lithium-rich cathode material as described above, comprising the following steps:
[0013] S1. Weigh lithium source, ruthenium source and titanium source according to stoichiometric ratio, and mix them by solid-phase high-energy ball milling to obtain a uniform precursor mixture;
[0014] S2. The precursor mixture is subjected to solid-phase compression to obtain a block precursor (the precursor is actually still a powder, but because it has been compressed, it appears as a block).
[0015] S3. The block precursor is sintered at high temperature in air: the temperature is increased to 930–980°C at a heating rate of 2–8°C / min, and held for 18–30 hours; preferably, the sintering temperature is 940–960°C, and the holding time is 20–26 hours. For example, the sintering temperatures are 930°C, 940°C, 950°C, 960°C, 970°C, and 980°C; and the holding times are 18h, 19h, 20h, 21h, 22h, 23h, 24h, 25h, and 26h.
[0016] S4. The sintered product is cooled to room temperature at a controlled rate of 1–5℃ / min, then ground and sieved to obtain a fast-charging layered lithium-rich cathode material.
[0017] In a preferred embodiment, in step S1, the lithium source is at least one of Li2CO3 and LiOH·H2O; and / or, the ruthenium source is at least one of RuO2 and RuCl3; and / or, the titanium source is at least one of TiO2 and H2TiO3.
[0018] The third objective of this application is to provide the application of the cathode material as described above or the cathode material prepared by the above method in high energy density, fast-charging lithium-ion batteries.
[0019] The beneficial effects of this invention are as follows:
[0020] 1. Achieve groundbreaking 10C fast charging performance at a high cutoff voltage of 4.6V.
[0021] Achieving 295 mAh g at 0.1C rate. -1 High reversible specific capacity; exhibiting excellent rate performance, maintaining 180 mAh g at a high rate of 10C. -1 After 100 cycles at a high cutoff voltage of 4.6V, the capacity retention rate is as high as 83%.
[0022] 2. This invention limits the Ti doping amount to a specific window (preferably x = 0.03–0.12): insufficient doping makes it difficult to simultaneously stabilize the oxygen framework and reduce the Li+ migration barrier, while excessive doping may weaken the effective Ru active sites and introduce transport side effects, leading to a decrease in rate performance. Therefore, this invention achieves the synergistic benefits of both 10C fast charging and high capacity through windowed composition design.
[0023] 3. The “sintering-controlled cooling” process brings about synergistic structural and kinetic strengthening.
[0024] This invention employs a sintering process involving high-energy ball milling for uniform mixing, tableting-crushing molding, high-temperature long-term solution treatment (930–980℃), and controlled-rate cooling (1–5℃ / min, preferably 2–4℃ / min) to promote full solution of Ti at Ru sites and suppress segregation and defect accumulation, thus maintaining continuous two-dimensional Li. + The diffusion channels and structural integrity significantly reduce polarization and improve cycle stability under 10C fast charging conditions.
[0025] 4. Provide a controllable, scalable, and highly consistent preparation method.
[0026] The preparation method of this invention has well-defined process parameters, good repeatability, and is easy to scale up. By controlling the Ti doping amount (x value) and sintering regime, the crystal structure, morphology, and electrochemical performance of the material can be precisely controlled, providing a reliable technical route for the development of a series of fast-charging lithium-rich layered cathode materials. Attached Figure Description
[0027] Figure 1 This is a SEM image of the cathode material prepared in Example 1 of the present invention;
[0028] Figure 2 The image shows the XRD pattern of the cathode material prepared in Example 1 of this invention.
[0029] Figure 3 The first charge-discharge curves at 0.1C are shown for the cathode materials prepared in Example 1 and Comparative Example 1 of this invention.
[0030] Figure 4 This is a rate capability curve diagram of the cathode materials prepared in Example 1 and Comparative Example 1 of the present invention;
[0031] Figure 5 This is a cycling curve of the cathode material of Embodiment 1 of the present invention under room temperature conditions of 10C-4.6V.
[0032] Figure 6 The image shows the XRD pattern of the cathode material prepared in Comparative Example 1 of this invention. Detailed Implementation
[0033] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application.
[0034] In all examples and comparative examples, the purity of RuO2 was 99.9%, the purity of TiO2 was 98%, the purity of Li2CO3 was 99.0%, the purity of RuCl3 was 99.0%, the purity of H2TiO3 was 99.0%, and the purity of LiOH·H2O was 99.0%.
[0035] Example 1:
[0036] Li2Ru 0.95 Ti 0.05 Preparation of O3
[0037] 0.600 g RuO2, 0.019 g TiO2, and 0.403 g (15 wt% excess to compensate for volatilization at high temperature) of Li2CO3 were weighed and mixed in a solid state using a high-energy ball mill at 400 r / min for 1 h. The mixture was then pressed into a blocky precursor powder. The precursor powder was heated to 950 °C in air and held for 24 h, then cooled to room temperature. The heating and cooling rates were maintained at 5 °C / min. The mixture was then ground and sieved to obtain the fast-charging layered lithium-rich cathode material Li2Ru. 0.95 Ti 0.05 O3.
[0038] Doped Li2Ru 0.95 Ti 0.05 SEM image of O3 as follows Figure 1 As shown, the cathode material exhibits a submicron-scale polyhedral particle morphology, with Ru, Ti, and O uniformly distributed within the particles. XRD results are as follows. Figure 2 As shown, the XRD peaks exhibited are consistent with those of the parent material, indicating that titanium is uniformly doped into the bulk phase. The Li₂Ru obtained in this embodiment... 0.95 Ti 0.05 The electrochemical performance of O3 was tested. The test voltage range was 2–4.6 V, and the charge / discharge rate was 0.1 C. Figure 3 It can be seen that the first-cycle charge-discharge specific capacity of the lithium-rich layered cathode prepared in this embodiment is 295 mAh / g, and the coulombic efficiency is 95%; the rate performance of the lithium-rich layered cathode prepared in this embodiment is as follows: Figure 4 As shown, the 10C stability test performance is as follows: Figure 5 As shown ( Figure 5 The black curve represents specific capacity, and the gray curve represents efficiency. After 100 cycles of 10 C fast charging, the capacity retention rate is 83%. This indicates that the material exhibits excellent structural integrity during high-rate cycling, effectively suppressing crack generation and exacerbation of interfacial side reactions caused by strain accumulation, thus achieving excellent long-term cycling stability while realizing fast charging.
[0039] Example 2
[0040] Li2Ru 0.9 Ti 0.1 Preparation of O3
[0041] 0.935 g RuCl3, 0.040 g TiO2, and 0.426 g (15 wt% excess to compensate for volatilization at high temperature) of Li2CO3 were weighed and mixed in a solid state using a high-energy ball mill at 400 r / min for 1 h. The mixture was then pressed into a blocky precursor powder. The precursor powder was heated to 930 °C in air and held for 30 h, then cooled to room temperature at a heating rate of 2 °C / min and a cooling rate of 1 °C / min. After grinding and sieving, the fast-charging layered lithium-rich cathode material Li2Ru was obtained. 0.9 Ti 0.1 O3. The lithium-rich layered cathode prepared in this embodiment has a first-cycle charge-discharge specific capacity of 248 mAh / g and a coulombic efficiency of 79%; the capacity retention rate of the lithium-rich layered cathode prepared in this embodiment after 100 cycles of 10 C fast charging is 88%.
[0042] Example 3
[0043] Li2Ru0.99 Ti 0.01 Preparation of O3
[0044] 0.6 g RuO2, 0.005 g H2TiO3, and 0.387 g (15 wt% excess to compensate for volatilization at high temperature) of Li2CO3 were weighed and mixed in a solid state using a high-energy ball mill at a speed of 400 r / min for 1 h. The mixture was then pressed into a blocky precursor powder. The precursor powder was heated to 980 °C in air and held for 18 h, then cooled to room temperature. The heating rate was maintained at 8 °C / min, and the cooling rate at 2 °C / min. After grinding and sieving, the fast-charging layered lithium-rich cathode material Li2Ru was obtained. 0.99 Ti 0.01 O3. The lithium-rich layered cathode prepared in this embodiment has a first-cycle charge-discharge specific capacity of 268 mAh / g and a coulombic efficiency of 88%; the capacity retention rate of the lithium-rich layered cathode prepared in this embodiment after 100 cycles of 10 C fast charging is 83%.
[0045] Example 4
[0046] Li2Ru 0.75 Ti 0.25 Preparation of O3
[0047] Weigh out 0.468g RuCl3, 0.300g RuO2, 0.147g H2TiO3, and 0.511g (15wt% excess to compensate for volatilization at high temperature) of LiOH·H2O. Mix the three materials in a solid-state environment using a high-energy ball mill at 400 r / min for 1 h. Then, perform solid-state compression to obtain a blocky precursor powder. Heat the precursor powder to 940℃ in air and hold for 20 hours, then cool to room temperature. Maintain a heating rate of 3℃ / min and a cooling rate of 2℃ / min. Grind and sieve to obtain the fast-charging layered lithium-rich cathode material Li2Ru. 0.75 Ti 0.25 O3. The lithium-rich layered cathode prepared in this embodiment has a first-cycle charge-discharge specific capacity of 234 mAh / g and a coulombic efficiency of 70%; the lithium-rich layered cathode prepared in this embodiment retains 80% of its capacity after 100 cycles of 10 C fast charging.
[0048] Example 5
[0049] Li2Ru 0.97 Ti 0.03 Preparation of O3
[0050] 0.935 g RuCl3, 0.011 g TiO2, and 0.395 g (15 wt% excess to compensate for volatilization at high temperature) of Li2CO3 were weighed and mixed in a solid state using a high-energy ball mill at 400 r / min for 1 h. The mixture was then pressed into a blocky precursor powder. The precursor powder was heated to 960 °C in air and held for 26 h, then cooled to room temperature at a heating rate of 6 °C / min and a cooling rate of 2 °C / min. After grinding and sieving, the fast-charging layered lithium-rich cathode material Li2Ru was obtained. 0.88 Ti 0.12 O3. The lithium-rich layered cathode prepared in this embodiment has a first-cycle charge-discharge specific capacity of 275 mAh / g and a coulombic efficiency of 91%; the capacity retention rate of the lithium-rich layered cathode prepared in this embodiment after 100 cycles of 10 C fast charging is 82%.
[0051] Example 6
[0052] Li2Ru 0.88 Ti 0.12 Preparation of O3
[0053] Weigh out 0.300g RuO2, 0.468g RuCl3, 0.064g H2TiO3, 0.025g TiO2, and 0.435g (15wt% excess to compensate for volatilization at high temperature) of Li2CO3. Mix the three materials in a solid-state environment using a high-energy ball mill at 400 r / min for 1 h. Then, perform solid-state compression to obtain a blocky precursor powder. Heat the precursor powder to 950℃ in air and hold for 23 hours, then cool to room temperature. Maintain a heating rate of 5℃ / min and a cooling rate of 4℃ / min. Grind and sieve to obtain the fast-charging layered lithium-rich cathode material Li2Ru. 0.88 Ti 0.12 O3. The lithium-rich layered cathode prepared in this embodiment has a first-cycle charge-discharge specific capacity of 246 mAh / g and a coulombic efficiency of 87%; the lithium-rich layered cathode prepared in this embodiment retains 70% of its capacity after 100 cycles of 10 C fast charging.
[0054] Example 7
[0055] Li2Ru 0.96 Ti 0.04 Preparation of O3
[0056] 0.6 g RuO2, 0.015 g TiO2, and 0.399 g (15 wt% excess to compensate for volatilization at high temperature) of Li2CO3 were weighed and mixed in a solid state using a high-energy ball mill at 400 r / min for 1 h. The mixture was then pressed into a blocky precursor powder. The precursor powder was heated to 970 °C in air and held for 18 h, then cooled to room temperature. The heating rate was maintained at 8 °C / min, and the cooling rate at 2 °C / min. After grinding and sieving, the fast-charging layered lithium-rich cathode material Li2Ru was obtained. 0.96 Ti 0.04 O3. The lithium-rich layered cathode prepared in this embodiment has a first-cycle charge-discharge specific capacity of 290 mAh / g and a coulombic efficiency of 92%; the lithium-rich layered cathode prepared in this embodiment retains 80% of its capacity after 100 cycles of 10 C fast charging.
[0057] Example 8
[0058] Li2Ru 0.92 Ti 0.08 Preparation of O3
[0059] 0.6 g RuO2, 0.031 g TiO2, and 0.416 g (15 wt% excess to compensate for volatilization at high temperature) of Li2CO3 were weighed and mixed in a solid state using a high-energy ball mill at 400 r / min for 1 h. The mixture was then pressed into a blocky precursor powder. The precursor powder was heated to 980 °C in air and held for 20 h, then cooled to room temperature. The heating rate was maintained at 5 °C / min, and the cooling rate at 2 °C / min. After grinding and sieving, the fast-charging layered lithium-rich cathode material Li2Ru was obtained. 0.92 Ti 0.08 O3. The lithium-rich layered cathode prepared in this embodiment has a first-cycle charge-discharge specific capacity of 262 mAh / g and a coulombic efficiency of 89%; the capacity retention rate of the lithium-rich layered cathode prepared in this embodiment after 100 cycles of 10 C fast charging is 82%.
[0060] Comparative Example 1
[0061] Li₂RuO₃ powder was synthesized by solid-state sintering. 0.383 g of Li₂CO₃ (15 wt.% excess) and 0.600 g of RuO₂ were weighed and mixed in a solid state using a high-energy ball mill at 400 r / min for 1 h. The mixture was then calcined at 900 °C for 12 h at a heating rate of 2 °C / min, followed by natural cooling. The XRD results of the unmodified material obtained in this comparative example are shown below. Figure 6As shown in the figure, its characteristic peaks agree well with the standard PDF card, indicating a classic layered structure of Li₂RuO₃. This demonstrates good crystallinity and a well-developed layered structure. The electrochemical performance of the Li₂RuO₃ obtained in this comparative example was then tested. The test voltage range was 2–4.6 V, and the charge / discharge rate was 0.1 C. Figure 3 It can be seen that the first charge-discharge specific capacity of the lithium-rich layered cathode prepared in this comparative example is 265 mAh / g, and the coulombic efficiency is 87%. Figure 4 The scaling tests showed that this comparative sample could not cycle normally under 10C test conditions.
[0062] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A fast-charging layered lithium-rich cathode material, characterized in that, The cathode material is Ti-doped lithium ruthenium oxide with the general chemical formula Li₂Ru. 1-x Ti x O3, where 0.01 < x ≤ 0.
25.
2. The cathode material according to claim 1, characterized in that, In the general chemical formula, 0.03 ≤ x ≤ 0.
12.
3. The cathode material according to claim 2, characterized in that, In the general chemical formula, 0.04 ≤ x ≤ 0.
08.
4. The cathode material according to claim 1, characterized in that, Ti is uniformly distributed in the layered crystal structure of lithium ruthenium oxide in the form of a solid solution, forming a stable Li₂Ru. 1-x Ti x O3 single-phase structure.
5. The positive electrode material according to claim 1, characterized in that, The cathode material has an initial discharge specific capacity of ≥150 mAh / g at 10C rate; and / or, after 100 cycles at 10C rate and room temperature of 2–4.6 V, the capacity retention is ≥80%.
6. The cathode material according to claim 1, characterized in that, The cathode material exhibits a submicron-scale polyhedral particle morphology, with a typical particle size on the order of hundreds of nanometers; and the Ru, Ti, and O in the cathode material are uniformly distributed within the particles.
7. A method for preparing the fast-charging layered lithium-rich cathode material as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Weigh lithium source, ruthenium source and titanium source according to stoichiometric ratio, and mix them by solid-phase high-energy ball milling to obtain a uniform precursor mixture; S2. The precursor mixture is subjected to solid-phase compression to obtain a block precursor; S3. The block precursor is sintered at high temperature in air: the temperature is increased to 930–980°C at a heating rate of 2–8°C / min, and held for 18–30 hours. S4. The sintered product is cooled to room temperature at a controlled rate of 1–5℃ / min, then ground and sieved to obtain a fast-charging layered lithium-rich cathode material.
8. The preparation method according to claim 7, characterized in that, In step S1, the lithium source is at least one of Li2CO3 and LiOH·H2O; and / or, the ruthenium source is at least one of RuO2 and RuCl3; and / or, the titanium source is at least one of TiO2 and H2TiO3.
9. The preparation method according to claim 7, characterized in that, In step S3, the sintering temperature is 940–960℃, and / or the holding time is 20–26 hours.
10. The application of the cathode material as described in any one of claims 1-6 or the cathode material prepared by any one of claims 7-9 in a high-energy-density, fast-charging lithium-ion battery.