A halide solid-state electrolyte and its application in all-solid-state batteries
Patent Information
- Application Number
- CN202611012347.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-08
- Publication Date
- 2026-08-18
AI Technical Summary
[0003]目前，现有的具有电化学活性的Li3MCl6(M=Ti, V)固态电解质由于离子电导率较低，以该类材料单独作为正极和氧化物正极添加剂，组装的全固态电池的倍率性能和循环稳定性较差
本发明提出了一种基于多元素掺杂的电化学活性卤化物固态电解质 Li-Ti/V/Cr-M-Cl，通过引入特定Ta 元素对材料进行掺杂改性，调控卤化物固态电解质的结构特征与离子传输行为，从而提高锂离子电导率并改善全固态锂电池的倍率性能和循环稳定性；同时，将所述电化学活性卤化物固态电解质引入氧化物正极复合体系中，可在不降低结构稳定性的前提下减少惰性组分比例，提高正极的有效容量与整体能量密度。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of all-solid-state lithium batteries and relates to a halide solid electrolyte and its application in all-solid-state batteries. Background Technology
[0002] The composite cathode of inorganic all-solid-state lithium batteries typically consists of an oxide cathode active material, a solid electrolyte, and a conductive carbon material. Since the solid electrolyte and conductive carbon materials used in the composite cathode generally do not participate in electrochemical reactions and are considered inert components, their mass fraction can typically reach approximately 30-40 wt%, leading to a decrease in the effective energy density of the composite cathode. Therefore, developing electrochemically active solid electrolyte materials while ensuring ion transport performance and structural stability is crucial for reducing the proportion of inert components and improving the energy density of all-solid-state lithium batteries.
[0003] Currently, existing electrochemically active Li3MCl6 (M=Ti, V) solid electrolytes suffer from low ionic conductivity, resulting in poor rate performance and cycle stability in all-solid-state batteries when used alone as the cathode or as an oxide cathode additive. Therefore, developing electrochemically active solid electrolytes with higher ionic conductivity is crucial for improving battery performance. Summary of the Invention
[0004] This invention prepares a Ta-doped electrochemically active halide solid electrolyte, Li-Ti / V / Cr-M-Cl. Ta doping modification improves the lithium-ion transport capability of the material, resulting in a lithium-ion conductivity of 10⁻⁶ for the electrochemically active halide solid electrolyte. -3 S cm -1 Introducing the electrochemically active halide solid electrolyte into the composite cathode and assembling an all-solid-state lithium battery can achieve good rate performance and cycle stability. At the same time, when it is used in combination with oxide cathode materials (including lithium iron phosphate, lithium cobalt oxide and lithium nickel cobalt manganese oxide), the effective capacity and overall energy density of the cathode can be improved without reducing structural stability.
[0005] The present invention adopts the following technical solution: This invention provides a solid electrolyte with the chemical formula Li. x A 1-y M y Cl6, where A is selected from one or more of Ti, V and Cr, and M is Ta; the valence state of A is a+ and the valence state of M is b+, then x = 6 - a + (ab)y, and 0 ≤ y < 0.25.
[0006] In the above technical solution, the solid electrolyte has the chemical formula Li. 2.8 Ti0.9 Ta 0.1 Cl6.
[0007] The present invention also provides a method for preparing the above-mentioned solid electrolyte, the method comprising mixing a halide containing Li, Ti, V or Cr with a halide containing Ta in a stoichiometric ratio, ball milling and then calcining.
[0008] In the above technical solution, the halide containing Li, Ti, V or Cr is one or more of LiCl, TiCl3, VCl3 and CrCl3; the halide containing Ta is TaCl5.
[0009] In the above technical solution, the ball milling is further described as a process of ball milling at a speed of 300-500 rpm for 12-36 hours.
[0010] In the above technical solution, the sintering temperature is further described as 200-300 ℃.
[0011] The present invention also provides the application of the above-mentioned solid electrolyte in all-solid-state batteries.
[0012] Furthermore, in the above technical solution, the solid electrolyte is used alone as the electrochemically active component in the positive electrode of the all-solid-state battery, thereby improving the rate performance and energy density of the all-solid-state lithium battery.
[0013] In the above technical solution, when the positive electrode of the all-solid-state battery is a composite positive electrode, the composite positive electrode comprises an oxide positive electrode material and the solid electrolyte; the oxide positive electrode material is lithium iron phosphate, lithium cobalt oxide, or lithium nickel cobalt manganese oxide.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention proposes a multi-element doped electrochemically active halide solid electrolyte, Li-Ti / V / Cr-M-Cl. By introducing specific Ta elements to modify the material, the structural characteristics and ion transport behavior of the halide solid electrolyte are regulated, thereby improving lithium-ion conductivity and enhancing the rate performance and cycle stability of all-solid-state lithium batteries. Simultaneously, introducing the electrochemically active halide solid electrolyte into the oxide cathode composite system can reduce the proportion of inert components without compromising structural stability, thus increasing the effective capacity and overall energy density of the cathode. Attached Figure Description
[0015] Figure 1 X-ray diffraction (XRD) spectrum of the solid electrolyte prepared in Example 1 of the application.
[0016] Figure 2 Scanning electron microscope (SEM) image of the solid electrolyte prepared in Example 1 of the application.
[0017] Figure 3 Electrochemical impedance spectroscopy (EIS) of the solid electrolyte prepared in Example 1 of the application.
[0018] Figure 4 The cycle performance of an all-solid-state battery assembled with the solid electrolyte prepared in Example 1 as the positive electrode alone.
[0019] Figure 5 The first charge-discharge curve of the solid electrolyte prepared in Example 1 of the application in a lithium iron phosphate (LFP) all-solid-state battery.
[0020] Figure 6 The first charge-discharge curve of the solid electrolyte prepared in Example 1 of the application in a lithium cobalt oxide (LCO) all-solid-state battery.
[0021] Figure 7 The first charge-discharge curve of the solid electrolyte prepared in Example 1 of the application in a lithium nickel cobalt manganese oxide (NCM811) all-solid-state battery.
[0022] Figure 8 The cycling performance of the solid electrolyte prepared in Example 1 of this application in a lithium nickel cobalt manganese oxide (NCM811) all-solid-state battery was investigated.
[0023] Figure 9 Electrochemical impedance spectroscopy (EIS) of the solid electrolyte prepared for Comparative Example 1.
[0024] Figure 10 The first charge-discharge curve of the solid electrolyte prepared for Comparative Example 1 in a lithium iron phosphate (LFP) all-solid-state battery.
[0025] Figure 11 The first charge-discharge curve of the solid electrolyte prepared for Comparative Example 1 in a lithium cobalt oxide (LCO) all-solid-state battery.
[0026] Figure 12 The first charge-discharge curve of the solid electrolyte prepared for Comparative Example 1 in a lithium nickel cobalt manganese oxide (NCM811) all-solid-state battery.
[0027] Figure 13 Electrochemical impedance spectroscopy (EIS) of the solid electrolyte prepared for Comparative Example 2.
[0028] Figure 14 Electrochemical impedance spectroscopy (EIS) of the solid electrolyte prepared for Comparative Example 3.
[0029] Figure 15 The first charge-discharge curve of the solid electrolyte prepared for Comparative Example 3 in a lithium iron phosphate (LFP) all-solid-state battery.
[0030] Figure 16 The first charge-discharge curve of the solid electrolyte prepared for Comparative Example 3 in a lithium cobalt oxide (LCO) all-solid-state battery.
[0031] Figure 17 The first charge-discharge curve of the solid electrolyte prepared for Comparative Example 3 in a lithium nickel cobalt manganese oxide (NCM811) all-solid-state battery.
[0032] Figure 18 The application is for the cycling performance of the solid electrolyte prepared in Comparative Example 3 in an all-solid-state battery of lithium nickel cobalt manganese oxide (NCM811).
[0033] Figure 19 Electrochemical impedance spectroscopy (EIS) of the solid electrolyte prepared in Comparative Example 4 for application.
[0034] Figure 20 The application is to evaluate the cycle performance of an all-solid-state battery assembled with the solid electrolyte prepared in Comparative Example 4 as the sole positive electrode. Detailed Implementation
[0035] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0036] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0037] Example 1 This embodiment provides an electrochemically active halide solid electrolyte Li 2.8 Ti 0.9 Ta 0.1 Preparation of Cl6 and its application in all-solid-state lithium batteries.
[0038] Preparation of solid electrolyte Li 2.8 Ti 0.9 Ta 0.1 The method for preparing Cl6 is as follows: LiCl, TiCl3, and TaCl5 are weighed and mixed in an argon-filled glove box at a molar ratio of 1:0.9:0.1, and then placed in a ball mill jar at a ball-to-material ratio of 1:40 by mass. The mixture is ball-milled at 400 rpm for 24 h, and then the resulting powder is sintered at 200°C for 6 h to obtain the solid electrolyte Li. 2.8 Ti 0.9 Ta 0.1 Cl6, structural and morphological characterization as follows Figure 1-2 The introduction of Ta did not change the original crystal structure, and Ta was uniformly distributed in the material.
[0039] In this embodiment, Ta is doped, specifically high-valence Ta. 5+ Ti in Li3TiCl6 3+This can create more vacancies in the material, which is beneficial to Li + Migration can simultaneously cause the transition metal layer to shrink and the Li layer to expand, further promoting Li migration. + Migration, thereby increasing the ionic conductivity of Li3TiCl6.
[0040] The solid electrolyte was tested and found to have a lithium-ion conductivity of 1.5 mS / cm. -1 The relevant test results are as follows Figure 3 As shown.
[0041] Li 2.8 Ti 0.9 Ta 0.1 Cl6 and C65 were ground in an agate mortar at a mass ratio of 9:1 for 10 minutes. 60 mg of Li3YCl6 and 40 mg of Li... 5.5 PS 4.5 Cl 1.5 As a double separator, using Li-In alloy as the negative electrode, and the prepared Li 2.8 Ti 0.9 Ta 0.1 A solid-state battery was assembled using Cl6 cathode material. The battery was subjected to long-cycle performance testing at 0.5C rate, and the results are as follows: Figure 4 As shown.
[0042] Lithium iron phosphate (LFP), lithium cobalt oxide (LCO), and lithium nickel cobalt manganese oxide (NCM811) were used as positive electrode active materials, respectively, and reacted with the Li 2.8 Ti 0.9 Ta 0.1 A composite positive electrode (10 mg) was prepared using Cl6 solid electrolyte and conductive carbon C65, including positive electrode active materials and Li. 2.8 Ti 0.9 Ta 0.1 The mass ratio of Cl6 solid electrolyte to conductive carbon C65 is 60:40:5, and Li3ZrCl4O is used. 1.5 (60 mg) and Li 5.5 PS 4.5 Cl 1.5 A double-layer separator structure composed of 40 mg of [material name missing] was assembled into an all-solid-state battery using a Li-In alloy as the negative electrode. The electrochemical performance of the battery was tested at a 0.1 C rate, and the results are as follows: Figures 5-8 As shown.
[0043] Comparative Example 1 This comparative example provides an inert halide oxide solid electrolyte Li3ZrCl4O 1.5 Preparation of and application of it in all-solid-state lithium batteries.
[0044] Li₂O and ZrCl₄ were weighed and mixed in an argon-filled glove box at a molar ratio of 1.5:1, and then placed in a ball mill jar at a ball-to-material ratio of 1:40 by mass. The mixture was ball-milled at 400 rpm for 18 h, and the resulting powder was collected to prepare the inert solid electrolyte Li₃ZrCl₄O. 1.5 .
[0045] Lithium iron phosphate (LFP), lithium cobalt oxide (LCO), and lithium nickel cobalt manganese oxide (NCM811) were used as positive electrode active materials, respectively, and reacted with the Li3ZrCl4O 1.5 Solid electrolyte and conductive carbon C65 are used to prepare a composite positive electrode, positive electrode active material, Li3ZrCl4O 1.5 The mass ratio of solid electrolyte to conductive carbon C65 is 60:40:5; Li3ZrCl4O is used. 1.5 / Li 5.5 PS 4.5 Cl 1.5 A double-layer separator structure was constructed, with a Li-In alloy as the negative electrode, to assemble an all-solid-state lithium battery. The electrochemical performance of the battery was tested at a 0.1 C rate, and the results are as follows: Figure 10 – Figure 12 As shown. Compared with the solid electrolyte of Example 1, the capacity of the composite cathode prepared using the solid electrolyte of Comparative Example 1 was not significantly improved.
[0046] Comparative Example 2 This comparative example provides an electrochemically active halide solid electrolyte Li 2.5 Ti 0.75 Ta 0.25 Preparation of Cl6 and its application in all-solid-state lithium batteries.
[0047] LiCl, TiCl3, and TaCl5 were weighed and mixed in an argon-filled glove box at a molar ratio of 1:0.75:0.25, and then placed in a ball mill jar at a ball-to-powder ratio of 1:40 by mass. The mixture was ball-milled at 400 rpm for 24 h, and the resulting powder was then sintered at 200 °C for 6 h to prepare the solid electrolyte Li. 2.5 Ti 0.75 Ta 0.25 Cl6.
[0048] The solid electrolyte was tested and found to have a lithium-ion conductivity of 0.63 mS / cm. 1 The relevant test results are as follows Figure 13 As shown. Due to a large amount of Ta 5+ The introduction of the LiTaCl6 phase resulted in a significant reduction in ionic conductivity compared to the solid electrolyte synthesized in Example 1.
[0049] Comparative Example 3 This comparative example provides the preparation of an undoped electrochemically active halide solid electrolyte, Li3TiCl6, and its application in all-solid-state lithium batteries.
[0050] LiCl and TiCl3 were weighed and mixed in an argon-filled glove box at a molar ratio of 3:1, and then placed in a ball mill jar at a ball-to-material ratio of 1:40 by mass. The mixture was ball-milled at 400 rpm for 18 h, and the resulting powder was then sintered at 200 °C for 6 h to prepare the solid electrolyte Li3TiCl6. The lithium-ion conductivity of this solid electrolyte was measured to be 0.52 mS / cm. 1 The relevant test results are as follows Figure 14 As shown, due to the confined lithium-ion migration pathways within the material, a larger lithium-ion migration activation energy is achieved, resulting in a significant decrease in ionic conductivity compared to the solid electrolyte of Example 1.
[0051] Lithium iron phosphate (LFP), lithium cobalt oxide (LCO), and lithium nickel cobalt manganese oxide (NCM811) were used as positive electrode active materials, respectively, and composite positive electrodes were prepared with the Li3TiCl6 solid electrolyte and conductive carbon C65. The mass ratio of positive electrode active material, Li3TiCl6 solid electrolyte, and conductive carbon C65 was 60:40:5. Li3ZrCl4O was used. 1.5 / Li 5.5 PS 4.5 Cl 1.5 A double-layer separator structure was constructed, with a Li-In alloy as the negative electrode, to assemble an all-solid-state lithium battery. The electrochemical performance of the battery was tested at a 0.1 C rate, and the results are as follows: Figure 15 – Figure 17 As shown. Compared with the solid electrolyte of Example 1, the composite cathode prepared using the solid electrolyte of Comparative Example 3 showed less capacity improvement.
[0052] Comparative Example 4 This embodiment provides an electrochemically active halide solid electrolyte Li 2.6 Ti 0.6 Zr 0.4 Preparation of Cl6 and its application in all-solid-state lithium batteries.
[0053] LiCl, TiCl3, and ZrCl4 were weighed and mixed in an argon-filled glove box at a molar ratio of 1:0.6:0.4, and then placed in a ball mill jar at a ball-to-powder ratio of 1:40 by mass. The mixture was ball-milled at 400 rpm for 24 h, and the resulting powder was then sintered at 300°C for 6 h to prepare the solid electrolyte LiCl. 2.6 Ti 0.6 Zr0.4 Cl6. The lithium-ion conductivity of this solid electrolyte was tested to be 1.4 mS / cm. 1 The relevant test results are as follows Figure 19 As shown. Compared with Example 1, the ionic conductivity decreased slightly.
[0054] Li 2.6 Ti 0.6 Zr 0.4 Cl6 and C65 were ground in an agate mortar at a mass ratio of 9:1 for 10 minutes. 60 mg of Li3YCl6 and 40 mg of Li... 5.5 PS 4.5 Cl 1.5 As a double separator, using Li-In alloy as the negative electrode, and the prepared Li 2.6 Ti 0.6 Zr 0.4 A Cl6 cathode was assembled into an all-solid-state battery. Electrochemical performance tests were conducted on the battery at a rate of 0.1C. The cycle stability of the all-solid-state battery was significantly lower than that of the solid electrolyte prepared in Example 1 at 0.5C, as shown in the results below. Figure 20 As shown.
[0055] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A solid electrolyte, characterized in that, The solid electrolyte has the chemical formula Li. x A 1-y M y Cl6, Where A is selected from one or more of Ti, V and Cr, and M is Ta; the valence state of A is a+, and the valence state of M is b+, then x = 6 - a + (ab)y, and 0 ≤ y < 0.
25.
2. The solid electrolyte according to claim 1, characterized in that, The solid electrolyte has the chemical formula Li. 2.8 Ti 0.9 Ta 0.1 Cl6.
3. A method for preparing a solid electrolyte as described in claim 1, characterized in that, According to the stoichiometric ratio, halides containing Li, Ti, V or Cr are mixed with halides containing Ta, ball-milled and then calcined.
4. The method for preparing a solid electrolyte according to claim 3, characterized in that, The halide containing Li, Ti, V or Cr is one or more of LiCl, TiCl3, VCl3 and CrCl3; the halide containing Ta is TaCl5.
5. The method for preparing a solid electrolyte according to claim 3, characterized in that, The ball milling process is carried out at a speed of 300-500 rpm for 12-36 hours.
6. The method for preparing a solid electrolyte according to claim 3, characterized in that, The sintering temperature is 200-300 ℃.
7. The solid electrolyte of claim 1 is used in an all-solid-state battery.
8. The application according to claim 7, characterized in that, The solid electrolyte is used alone as the electrochemically active component in the positive electrode of the all-solid-state battery.
9. The application according to claim 7, characterized in that, The positive electrode of the all-solid-state battery comprises an oxide positive electrode material and the solid electrolyte; the oxide positive electrode material is lithium iron phosphate, lithium cobalt oxide, or lithium nickel cobalt manganese oxide.