Oxide solid electrolyte and application thereof
The preparation of the oxide solid electrolyte Li3La(PO4)2 by Li+ replacement of Na3La(PO4)2 is solved, and the problem of difficult processing of oxide solid electrolytes is realized, the preparation of all-solid state batteries is improved, and the safety and energy density of the battery are improved.
Patent Information
- Application Number
- CN202311633376.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-30
- Publication Date
- 2025-07-25
AI Technical Summary
Due to the high Young's modulus, oxide solid electrolytes are difficult to be processed into thin sheets and cannot be used to prepare all-solid state batteries.
Li+ was used to replace Na+ in Na3La(PO4)2 to prepare an oxide solid electrolyte Li3La(PO4)2 with Young's modulus less than 50 Gpa to replace the sulfide solid electrolyte.
The low Young's modulus of oxide solid electrolytes is achieved, which can be used to prepare all-solid state batteries, improving the safety and energy density of the batteries.
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Figure CN120376730A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of all-solid-state batteries, and particularly to an oxide solid electrolyte and its use. Background Art
[0002] Lithium-ion batteries are currently the energy storage devices with the highest energy density. However, the energy density has gradually reached its upper limit, and the improvement of the energy density has made the safety issues of lithium-ion batteries increasingly prominent. All-solid-state batteries are expected to become energy storage devices with higher specific energy density and better safety than lithium-ion batteries. The performance of the solid electrolyte is the most crucial factor determining the performance of all-solid-state batteries.
[0003] Solid electrolytes include oxide solid dielectrics and sulfide solid electrolytes. Among them, sulfide solid electrolytes, due to their relatively small Young's modulus, can usually form a dense film by cold pressing at room temperature and can be directly used for the assembly of all-solid-state batteries. Therefore, sulfide solid electrolytes are particularly suitable for preparing all-solid-state batteries.
[0004] For oxide solid electrolytes, due to their relatively high Young's modulus and large hardness, it is usually difficult to process them into thin sheets. Therefore, oxide solid electrolytes usually cannot be used to prepare all-solid-state batteries. Currently, no oxide solid electrolyte with a low Young's modulus has been found in the industry. Summary of the Invention
[0005] In view of this, the present invention provides an oxide solid electrolyte and its use to solve the problem that oxide solid electrolytes cannot be used to prepare all-solid-state batteries.
[0006] In a first aspect, the present invention provides an oxide solid electrolyte, and the chemical formula of the oxide solid electrolyte is Li3La(PO4)2.
[0007] The present invention provides an oxide solid electrolyte with the chemical formula of Li3La(PO4)2. Through the research of the inventor, it is found that this oxide solid electrolyte has a low Young's modulus and can replace sulfide solid dielectrics and be used to prepare all-solid-state batteries. Therefore, this application provides a new solid electrolyte material for all-solid-state batteries.
[0008] In an optional embodiment, the Young's modulus of the oxide solid electrolyte is less than 50 GPa, preferably less than 20 MPa.
[0009] In an optional embodiment, the oxide solid electrolyte is prepared by replacing Na in Na3La(PO4)2 with Li + After replacing Na in Na3La(PO4)2 with Li + It is found through the research of the inventor that by using Li + To replace Na in Na3La(PO4)2+ Afterwards, the residual lattice stress in the Li3La(PO4)2 lattice endows Li3La(PO4)2 with a low Young's modulus.
[0010] In an alternative embodiment, the preparation process of the oxide solid electrolyte includes:
[0011] (1) Contact Na3La(PO4)2 with a lithium salt, heat and stir. During the heating and stirring process, a substitution reaction between Na ions and Li ions occurs to obtain a mixture;
[0012] (2) Dissolve the soluble salts in the mixture obtained in step (1), then filter and wash the filter cake to obtain a crude Li3La(PO4)2 powder, and repeatedly wash this crude powder with alcohol or distilled water to obtain a pure Li3La(PO4)2 powder;
[0013] (3) Heat-treat the pure Li3La(PO4)2 powder obtained in step (2) to obtain the above-mentioned oxide solid electrolyte.
[0014] In an alternative embodiment, the substitution reaction in step (1) can be carried out in an aqueous solution, a non-aqueous liquid phase or a solid phase. The lithium salt can be an inorganic lithium salt and / or an organic lithium salt. When carrying out the substitution reaction, the heating temperature can be 50 - 600 °C, and the stirring time can be 2 - 100 h.
[0015] In an alternative embodiment, when washing in step (2), methanol, ethanol or deionized water can be used for washing. The temperature of the heat treatment in step (3) can be 50 - 400 °C, and the heat treatment time can be 2 - 10 h.
[0016] In a second aspect, the present invention provides the use of the above-mentioned oxide solid electrolyte in the preparation of a solid electrolyte for a solid-state battery.
[0017] In a third aspect, the present invention provides the use of the above-mentioned oxide solid electrolyte in the preparation of a positive electrode sheet for a solid-state battery.
[0018] In a fourth aspect, the present invention provides the use of the above-mentioned oxide solid electrolyte in the preparation of a solid-state battery.
[0019] In a fifth aspect, the present invention provides a solid electrolyte for a solid-state battery, and the solid electrolyte includes the above-mentioned oxide solid electrolyte.
[0020] In a sixth aspect, the present invention provides a positive electrode sheet for a solid-state battery, and the positive electrode sheet includes the above-mentioned oxide solid electrolyte.
[0021] Seventh aspect, the present invention provides a solid-state battery, and the solid-state battery includes the above-mentioned oxide solid electrolyte. Among them, the positive electrode of the solid-state battery can be a high-nickel positive electrode material or a conventional positive electrode material such as lithium iron phosphate, and the negative electrode can be a lithium metal alloy negative electrode or a carbon negative electrode.
[0022] In an alternative embodiment, the solid-state battery includes a all-solid-state battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0024] Figure 1 It is the x-ray diffraction pattern of Na3La(PO4)2 powder, the first reaction product, and Li3La(PO4)2 powder in Example 1 of the present invention;
[0025] Figure 2 It is the graph of the Young's modulus results of each solid electrolyte tested in Experimental Example 1 of the present invention;
[0026] Figure 3 It is the charge-discharge curve of the half-cell tested in Experimental Example 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0027] The following embodiments are provided to better further understand the present invention, which is not limited to the best embodiment, and does not limit the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior art features falls within the protection scope of the present invention.
[0028] For those embodiments where specific experimental steps or conditions are not indicated, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments whose manufacturers are not indicated, they are all conventional reagent products that can be obtained through commercial purchase.
[0029] The following further describes the present invention in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present invention.
[0030] Embodiment
[0031] Prepare the oxide solid electrolyte Li3La(PO4)2 according to the following method:
[0032] (1) Using Na2CO3 (Adamas, ≥99.8%), La2O3 (Adamas, 99.97%), and NH4H2PO4 (Sigma-Aldrich, ≥99.8%) as raw materials, they were thoroughly ground and mixed according to the stoichiometric molar ratio of Na:La:P of 3:1:4. The obtained mixture was placed in a muffle furnace at 400 °C for pretreatment for 5 h and then taken out, further ground to ensure the uniformity of the mixture, and then transferred to the muffle furnace. It was slowly heated to 1100 °C at a rate of 5 °C / min, maintained at 1100 °C for 10 h, and then the temperature was slowly lowered to room temperature. Finally, white Na3La(PO4)2 powder was obtained;
[0033] (2) In a glove box filled with argon, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid (EMIIM) were weighed and configured into an ionic liquid solution with a LiTFSI concentration of 2 mol / L;
[0034] (3) The Na3La(PO4)2 powder obtained in step (1) was mixed with the ionic liquid solution configured in step (2) such that the molar ratio of Li:Na was 5:1, and then the mixed material was transferred to the reaction kettle of a homogeneous reactor and sealed;
[0035] (4) The reaction kettle prepared in step (3) was transferred to a homogeneous reactor and subjected to ion exchange at 180 °C and a rotation speed of 50 rpm for 24 h and then taken out, cooled to room temperature, and a reaction crude product was obtained;
[0036] (5) The reaction crude product obtained in step (4) was washed with absolute ethanol. After the washing was completed, it was centrifuged at a rotation speed of 6000 rpm for 3 minutes using a centrifuge. After centrifugal washing multiple times, a first reaction product was obtained. Taking this reaction product as a raw material, steps (2), (3), and (4) were repeated. After repeating the reaction for 24 h, fully exchanged white Li3La(PO4)2 powder was obtained.
[0037] The Na3La(PO4)2 powder obtained in step (1), the first reaction product obtained in step (5), and the finally obtained Li3La(PO4)2 powder were respectively subjected to X-ray diffraction detection, and the obtained X-ray diffraction patterns are as Figure 1 shown. It can be seen from Figure 1 that in this example, the oxide solid electrolyte Li3La(PO4)2 was successfully prepared.
[0038] Experimental Example 1
[0039] This experimental example was used to compare the Young's modulus of the oxide solid electrolyte Li3La(PO4)2 prepared in the example with other solid electrolytes. The method was as follows:
[0040] Separate the solid electrolyte powders and place them in a mold. Use a powder press to maintain a uniaxial pressure of 800 MPa for 10 min, and press them into thin slices with a thickness of about 1 mm and a diameter of 10 mm. Test the Young's modulus of each solid electrolyte using an atomic force microscope. The test results are as Figure 2 and Table 1 shows.
[0041] Table 1 Young's modulus of each solid electrolyte
[0042] Solid electrolyte Young's modulus, GPa <![CDATA[Li 0.33 La 0.57 TiO3]]> 186 <![CDATA[Li 6.75 La3Zr 1.75 Ta 0.25 O 12 > 157 <![CDATA[Li 1.3 Al 0.3 Ti 1.7 O(PO4) 12 > 115 <![CDATA[Li3OCl]]> 105 <![CDATA[Li3Zr2Si2PO 12 > 93 <![CDATA[Li6PS5Cl]]> 22 <![CDATA[Na3PS 3.4 O 0.6 > 20.9 <![CDATA[Li3La(PO4)2]]> 19.1
[0043] From Figure 2 and Table 1, it can be seen that the Young's modulus of the oxide solid electrolyte Li3La(PO4)2 prepared in the examples is 19.1 GPa, which is much lower than that of other oxide solid electrolytes and is similar to that of chalcogenide solid electrolytes.
[0044] Experimental Example 2
[0045] Take 0.15 g of the Li3La(PO4)2 solid electrolyte powder prepared in the examples and pour it into a specific insulating mold with a special plunger. Use an automatic powder press to apply a uniaxial pressure of 800 Mpa to the Li3La(PO4)2 powder to press it into a Li3La(PO4)2 solid electrolyte thin slice; mix LiCoO2, Li3La(PO4)2 solid electrolyte, super carbon black, and polyvinylidene fluoride with a surface coating of 3 wt% LiNbO3 in a mass ratio of 4:4:1:1, and press them into a positive electrode plate in the same way; then stick the positive electrode plate and the lithium metal negative electrode on both sides of the Li3La(PO4)2 solid electrolyte thin slice respectively, load them into a special mold, seal it, and apply a uniaxial pressure of 100 Mpa on the press for 2 hours to ensure good interfacial contact between the positive electrode plate / Li3La(PO4)2 solid electrolyte / lithium metal negative electrode; then tighten the pressure maintaining bolt on the special mold and take it out of the press to obtain a LiCoO2 / Li3La(PO4)2 solid electrolyte / lithium metal half-cell.
[0046] Use a charge-discharge device to test the charge-discharge cycle performance of the above-prepared half-cell at room temperature at 0.05C in the voltage range of 3.0 - 4.2V, and plot the charge-discharge curve. The results are as Figure 3 shown. From Figure 3 it can be seen that the charge-discharge curve obtained in this experimental example is good, which indicates that a high-performance all-solid-state battery can be prepared using the oxide solid electrolyte of the present invention.
[0047] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or alterations derived therefrom still fall within the protection scope of this invention.
Claims
1. A solid oxide electrolyte, characterized in that, The chemical formula of the oxide solid electrolyte is Li3La(PO4)2.
2. The oxide solid electrolyte according to claim 1, characterized in that, The Young's modulus of the oxide solid electrolyte is less than 50 GPa, preferably less than 20 MPa.
3. The oxide solid electrolyte according to claim 1 or 2, characterized in that, The oxide solid electrolyte is prepared by using Li + to replace Na in Na3La(PO4)2 + and then obtained by preparation.
4. Use of the oxide solid electrolyte according to any one of claims 1 to 3 in the preparation of a solid electrolyte for a solid-state battery.
5. Use of the oxide solid electrolyte according to any one of claims 1 to 3 in the preparation of a positive electrode sheet for a solid-state battery.
6. Use of the oxide solid electrolyte according to any one of claims 1 to 3 in the preparation of a solid-state battery.
7. A solid electrolyte for a solid-state battery, characterized in that, The solid electrolyte includes the oxide solid electrolyte according to any one of claims 1 to 3.
8. A positive electrode sheet for a solid-state battery, characterized in that, The positive electrode sheet includes the oxide solid electrolyte according to any one of claims 1 to 3.
9. A solid-state battery, characterized in that, The solid-state battery includes the oxide solid electrolyte according to any one of claims 1 to 3.
10. The use according to any one of claims 4 to 6, or the solid electrolyte according to claim 7, or the positive electrode sheet according to claim 8, or the solid-state battery according to claim 9, characterized in that, The solid-state battery includes a all-solid-state battery.