Lithium ion conductor type lithium supplement agent, composite positive electrode material, positive electrode plate and battery
By preparing a lithium-ion conductor-type lithium replenisher, which releases excess lithium during battery cycling, the problem of gaseous residues affecting battery performance in existing technologies is solved, thereby improving battery capacity and cycle performance.
Patent Information
- Application Number
- CN202511693072.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-03-13
AI Technical Summary
Existing commercial cathode lithium replenishment additives generate gases or electrochemically inert residues during the lithium replenishment process, affecting the material's energy density and cycle performance.
A lithium-ion conductor-type lithium replenisher is prepared by reacting a strongly reducing organic lithium reagent with an inorganic solid electrolyte. This lithium-ion conductor-type lithium replenisher gradually releases excess lithium during battery cycling, thereby improving the ion conduction performance of the positive electrode.
It achieves a lithium replenishment process without gas generation, improving battery cycle performance and capacity, and extending battery life.
Smart Images
Figure CN121662817A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery technology, specifically relating to a lithium-ion conductor-type lithium replenishing agent, a composite cathode material, a cathode sheet, and a battery. Background Technology
[0002] Lithium-ion batteries are widely used in power and electronics fields due to their high energy density, fast response speed, high conversion efficiency, and long cycle life. However, lithium loss is inevitable during the cycling process of lithium-ion batteries, causing rapid capacity decay and a significant reduction in lifespan. Therefore, it is necessary to replenish lithium in the system by introducing additional lithium to compensate for the lithium loss during the electrochemical process.
[0003] Cathode lithium replenishment, as a common lithium replenishment method, has advantages such as convenient operation, high safety, and strong lithium replenishment capacity. However, currently available commercial cathode lithium replenishment additives often produce gaseous or electrochemically inert residues after achieving lithium replenishment. These byproducts reduce the energy density of the material to some extent and also have a negative impact on cycle performance. Therefore, there is an urgent need to develop a new lithium replenishment agent to solve these problems. Summary of the Invention
[0004] To address the problems mentioned in the background section, the present invention aims to provide a lithium-ion conductive lithium replenishing agent, a composite cathode material, a cathode electrode, and a battery. The present invention prepares an overlithiated inorganic solid electrolyte, which is used as a lithium replenishing agent without generating additional gas. Even after the lithium replenishing agent has fulfilled its function, the residue still possesses good ion conductivity, improving the cycle performance of the material and effectively increasing the capacity and cycle life of the entire battery. This is a simple and efficient method for replenishing lithium-ion batteries.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a lithium-ion conductor-type lithium replenishing agent, wherein the raw materials of the lithium-ion conductor-type lithium replenishing agent include: a strong reducing organic lithium reagent and an inorganic solid electrolyte;
[0006] The strong reducing organolithium reagent includes at least one of n-butyllithium, tert-butyllithium, and naphthenelithium;
[0007] The inorganic solid electrolyte is Li 1.3 Al 0.3 Ti 1.7 (PO4)3 (LATP).
[0008] Furthermore, the molar ratio of the strongly reducing organic lithium reagent to the inorganic solid electrolyte is (0.8-2):1.
[0009] Furthermore, the chemical formula of the lithium-ion conductor-type lithium supplement is Li. 1.3+xAl 0.3 Ti 1.7 (PO4)3, where 0.1≤x≤1.7.
[0010] The inorganic solid electrolyte used in this invention has good ion conduction performance. It can be reduced and intercalated with excess lithium by simple strong reducing organic reagent treatment. During battery cycling, the excess lithium can be gradually released to replenish the lithium in the battery system. At the same time, LATP, as a lithium-ion conductor, can improve the ion conduction inside the positive electrode and enhance its cycle performance.
[0011] On the other hand, the present invention provides a method for preparing any of the above-mentioned lithium-ion conductor-type lithium supplements, comprising the following steps:
[0012] The lithium-ion conductor-type lithium supplement is obtained by reacting an inorganic solid electrolyte with a strongly reducing organic lithium reagent in a protective atmosphere.
[0013] Furthermore, the reaction temperature is room temperature, and the reaction time is 24-60 hours, preferably 48 hours.
[0014] Furthermore, the protective atmosphere includes an argon atmosphere.
[0015] Furthermore, the process includes the following steps: after the reaction is complete, the mixture is filtered under a protective atmosphere, washed with an organic reagent, and dried.
[0016] Furthermore, the organic reagent is anhydrous n-hexane.
[0017] Furthermore, the drying conditions are vacuum, the drying temperature is 60-120℃, preferably 80℃, and the drying time is 8-24h, preferably 12h.
[0018] The method for preparing the lithium-ion conductor-type lithium replenishing agent used in this invention does not require any heating except for the final drying step. It is simple to operate and easy to prepare in large quantities.
[0019] On the other hand, the present invention provides a composite cathode material, comprising a cathode active material, a conductive additive, a binder, and a lithium-ion conductor-type lithium supplement agent as described above or a lithium-ion conductor-type lithium supplement agent prepared by any of the preparation methods described above.
[0020] Furthermore, the positive electrode active material includes Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O2.
[0021] Furthermore, the conductive additive includes at least one of Super P, carbon nanotubes, and Ketjen Black.
[0022] Furthermore, the adhesive comprises polyvinylidene fluoride (PVDF).
[0023] Furthermore, the mass ratio of the positive electrode active material, conductive additive, and binder is (70-90):(5-15):(5-15);
[0024] The mass ratio of the lithium-ion conductor-type lithium replenishing agent to the total mass of the positive electrode active material, conductive additive, and binder is (1-10):100.
[0025] In another aspect, the present invention provides a method for preparing any of the above-mentioned composite cathode materials, comprising the following steps:
[0026] The positive electrode active material and the lithium-ion conductor type lithium supplement are ground and mixed evenly to obtain the first mixture;
[0027] The first mixture, conductive additive, and binder solution are ground and mixed evenly to obtain the composite cathode material.
[0028] Furthermore, the adhesive solution is prepared by dissolving the adhesive in a solvent.
[0029] Furthermore, the adhesive solution is prepared by dissolving the adhesive in N-methylpyrrolidone.
[0030] The lithium-ion conductor-type lithium replenishing agent used in this invention needs to be pre-ground and mixed with the positive electrode active material to form a coating on its surface, so that it can still coat the surface of the positive electrode active material after delithiation during electrochemical cycling, thereby improving the material's cycle performance.
[0031] In another aspect, the present invention provides a positive electrode sheet comprising any of the lithium-ion conductor-type lithium replenishing agents described above, or lithium-ion conductor-type lithium replenishing agents prepared by any of the preparation methods described above, or composite positive electrode materials described above, or composite positive electrode materials prepared by any of the preparation methods described above.
[0032] Furthermore, it also includes current collectors.
[0033] Furthermore, the present invention provides a method for preparing the above-mentioned positive electrode sheet, comprising the following steps:
[0034] The composite positive electrode material is coated onto the current collector and dried to obtain the positive electrode sheet.
[0035] Furthermore, the current collector is aluminum foil.
[0036] Furthermore, the drying temperature is 60-80℃, and the drying time is 2-8 hours, preferably 4 hours.
[0037] In another aspect, the present invention provides a battery comprising any of the lithium-ion conductor-type lithium replenishing agents described above, or lithium-ion conductor-type lithium replenishing agents prepared by any of the preparation methods described above, or composite cathode materials described above, or composite cathode materials prepared by any of the preparation methods described above, or cathode plates described above.
[0038] Compared with the prior art, the present invention has the following beneficial effects:
[0039] 1) This invention achieves the excessive introduction of lithium ions by overlithiating the lithium-ion conductor and utilizing the valence state change of variable-valence transition metal ions, without introducing any components that generate gas after lithium replenishment. This results in no gas generation after lithium replenishment and the residue has good lithium-ion conductivity, thereby improving the cycle performance of the cathode material.
[0040] 2) When the lithium-ion conductor-type lithium replenishing agent of the present invention is used in lithium-ion batteries, the prepared lithium-ion batteries have excellent cycle stability, high capacity and high first-cycle specific capacity. Attached Figure Description
[0041] Figure 1 The charge-discharge cycle performance diagrams are for lithium-ion batteries prepared with lithium-ion conductor-type lithium replenishing agents provided in Examples 1-7 and Comparative Example 1 of this invention. Detailed Implementation
[0042] To better understand the content of this invention, the following detailed description is provided in conjunction with specific implementation methods. However, the scope of protection of this invention is not limited to the following embodiments.
[0043] In the following examples, abbreviations are used to represent the corresponding compounds, as follows:
[0044] LRMO is Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O2,
[0045] LATP is Li 1.3 Al 0.3 Ti 1.7 (PO4)3,
[0046] PVDF is polyvinylidene fluoride.
[0047] NMP is N-methylpyrrolidone.
[0048] Example 1
[0049] Preparation of lithium-ion conductor type lithium supplement: 684.9 mg of LATP was mixed with 15 mL of 0.2 mol / L n-butyllithium in n-hexane under an argon atmosphere and stirred continuously at room temperature for 48 h to obtain a suspension; the suspension was filtered under an argon atmosphere to obtain an impure lithium-ion conductor type lithium supplement, denoted as L-LATP; the impure L-LATP was mixed with 20 mL of anhydrous n-hexane and stirred for 30 min, and then filtered again; the above operation was repeated twice to obtain L-LATP; the dried L-LATP was obtained by drying in a vacuum oven at 80 °C for 12 h.
[0050] Preparation of composite cathode material: 80 mg of LRMO and 1 mg of L-LATP were ground evenly in an agate mortar, and then 10 mg of Super P and 200 mg of 5% PVDF NMP solution were added and ground evenly to obtain composite cathode material.
[0051] Preparation of positive electrode sheet: The composite positive electrode material is uniformly coated onto the aluminum current collector; the aluminum current collector carrying the composite positive electrode material is placed in a forced-air drying oven and heated to 60°C in an air atmosphere and kept for 4 hours to obtain the positive electrode sheet.
[0052] Example 2
[0053] The difference between Example 2 and Example 1 is that the mass of L-LATP used is 2 mg.
[0054] Example 3
[0055] The difference between Example 3 and Example 1 is that the mass of L-LATP used is 3 mg.
[0056] Example 4
[0057] The difference between Example 4 and Example 1 is that the mass of L-LATP used is 4 mg.
[0058] Example 5
[0059] The difference between Example 5 and Example 1 is that the mass of L-LATP used is 6 mg.
[0060] Example 6
[0061] The difference between Example 6 and Example 1 is that the mass of L-LATP used is 8 mg.
[0062] Example 7
[0063] The difference between Example 7 and Example 1 is that the mass of L-LATP used is 10 mg.
[0064] Comparative Example 1
[0065] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain the positive electrode lithium supplement L-LATP, while all other aspects are the same as Example 1.
[0066] Lithium-ion batteries were prepared using the positive electrode sheets prepared in Examples 1-7 and Comparative Example 1, respectively, as follows:
[0067] The positive electrode sheets prepared in Examples 1-7 and Comparative Example 1 were cut into LRMO positive electrode sheets with a diameter of 10 mm and vacuum dried at 150 °C for 12 h.
[0068] The LRMO positive electrode and graphite negative electrode were separated by a 25 μm thick Celgard 2400 battery separator (polypropylene). A 1 mol / L lithium hexafluorophosphate (LiPF6) solution was used as the electrolyte. The solvent for the lithium hexafluorophosphate solution was a mixed solvent of fluoroethylene carbonate (EC), methyl trifluoroethyl carbonate (FEMC), and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE), with a volume ratio of EC:2:6. The battery was assembled in an argon-filled glove box. The assembled battery was then pressurized to 50 MPa under a hydraulic press to obtain a coin-type lithium-ion battery.
[0069] The positive electrode electrochemical performance of the above-mentioned batteries was tested. The test voltage window was 2-4.7V, and continuous charge-discharge tests were conducted at a 1C rate. The test results are as follows: Figure 1 As shown in Table 1.
[0070] Table 1 Electrochemical performance test data
[0071]
[0072] from Figure 1 As shown in Table 1, the addition of the lithium-ion conductor-type lithium replenisher of this invention significantly improved the battery's initial specific capacity, increasing it by 98.2 mAh / g. Furthermore, the capacity after 300 cycles increased by 22.5%, demonstrating good cycle performance. This indicates that the addition of the lithium replenisher effectively compensated for the lithium ions consumed in SEI layer formation and side reactions, thus promoting capacity utilization and improving cycle performance.
[0073] The above description is only a specific embodiment of the present invention and not all embodiments. Any equivalent modifications made by those skilled in the art to the technical solutions of the present invention by reading the present invention specification shall be covered by the claims of the present invention.
Claims
1. A lithium-ion conductor-type lithium supplement, characterized in that, The raw materials for the lithium-ion conductor-type lithium supplement include: a strong reducing organic lithium reagent and an inorganic solid electrolyte; The strong reducing organolithium reagent includes at least one of n-butyllithium, tert-butyllithium, and naphthenelithium; The inorganic solid electrolyte is Li 1.3 Al 0.3 Ti 1.7 (PO4)3.
2. The lithium-ion conductor-type lithium supplement agent according to claim 1, characterized in that, The molar ratio of the strong reducing organic lithium reagent to the inorganic solid electrolyte is (0.8-2):
1.
3. The method for preparing the lithium-ion conductor-type lithium supplement agent according to any one of claims 1-2, characterized in that, Includes the following steps: The lithium-ion conductor-type lithium supplement is obtained by reacting an inorganic solid electrolyte with a strongly reducing organic lithium reagent in a protective atmosphere.
4. The preparation method according to claim 3, characterized in that, The reaction is carried out at room temperature for 24-60 hours.
5. A composite cathode material, characterized in that, It includes positive electrode active material, conductive additive, binder, and lithium-ion conductor type lithium replenishing agent as described in any one of claims 1-2 or prepared by the preparation method described in any one of claims 3-4.
6. The composite cathode material according to claim 5, characterized in that, The positive electrode active material includes Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O2; Preferably, the conductive additive includes at least one of Super P, carbon nanotubes, and Ketjen Black; Preferably, the adhesive comprises polyvinylidene fluoride.
7. The composite cathode material according to claim 5, characterized in that, The mass ratio of the positive electrode active material, conductive additive, and binder is (70-90):(5-15):(5-15); The mass ratio of the lithium-ion conductor-type lithium replenishing agent to the total mass of the positive electrode active material, conductive additive, and binder is (1-10):
100.
8. The method for preparing the composite cathode material according to any one of claims 5-7, characterized in that, Includes the following steps: The positive electrode active material and the lithium-ion conductor type lithium supplement are ground and mixed evenly to obtain the first mixture; The first mixture, conductive additive, and binder solution are ground and mixed evenly to obtain the composite cathode material.
9. A positive electrode sheet, characterized in that, This includes the lithium-ion conductor-type lithium replenishing agent according to any one of claims 1-2, or the lithium-ion conductor-type lithium replenishing agent prepared by the preparation method according to any one of claims 3-4, or the composite cathode material according to any one of claims 5-7, or the composite cathode material prepared by the preparation method according to claim 8.
10. A battery, characterized in that, Includes the lithium-ion conductor type lithium replenishing agent according to any one of claims 1-2, or the lithium-ion conductor type lithium replenishing agent prepared by the preparation method according to any one of claims 3-4, or the composite cathode material according to any one of claims 5-7, or the composite cathode material prepared by the preparation method according to claim 8, or the cathode sheet according to claim 9.