Silicate glass fast ion conductor material and preparation method thereof

Abstract

The invention discloses a silicate glass fast ion conductor material and a preparation method thereof, the chemical component of the silicate glass fast ion conductor material is AnBmSieOkMyXq, A is a carrier and comprises one or more of Li, Na, K, Ag and Cu; b is a doping ion in a silicate glass structure and comprises one or more of P, B, Al, Zn, Ca, Y, In, Zr, Hf, La, Ce, Ti, Sb, Bi, C, Ge, Sn, Pb and Ga; m is one or more of Ta, Ti, Zr, Hf, V, Nb, Y, In and Ga; x is one or more of F, Cl, Br, I, O, S and N; n, m, e, k, y and q are all integers, 0 < n < = 6, 0 < = m < = 3, 1 < = e < = 6, 4 < = k < = 16, 0 < = y < = 2, and 0 < = q < = 4. According to the invention, the network polymerization degree and the softening point of the material are obviously reduced, the Young modulus is regulated and controlled, an ion migration channel is expanded, the activation energy is reduced, and the quick charge requirement of a solid-state battery is met.

Description

Technical Field

[0001] The present invention relates to the field of silicate fast ion conductor materials, in particular to a silicate glass fast ion conductor material and a preparation method thereof. Background Art

[0002] Silicate glass fast ion conductors use Si, an element abundant in the Earth's crust, as their primary network component, offering the advantages of abundant resources and low cost. Therefore, the development of silicate glass fast ion conductors facilitates the large-scale production of solid-state electrolytes, thereby reducing reliance on scarce metal resources and alleviating pressure on resource consumption. Consequently, silicate glass fast ion conductors have become a promising class of materials due to their high stability, low cost, and abundance of key components. However, the application of silicate glass fast ion conductors in solid-state batteries is limited by two issues: first, poor interfacial contact between the electrode and the electrolyte prevents close contact between the electrode and the solid electrolyte; second, point-to-point contact between the electrode and the solid electrolyte during long cycling processes leads to slow ion transport, resulting in increased interfacial impedance and degradation of battery performance, necessitating attention to chemical-electro-mechanical phenomena; and finally, the low conductivity of oxide ions prevents them from meeting the high power output requirements of solid-state batteries.

[0003] Publication No. CN107437633A reports a method for sintering oxide electrolytes. By adding a lithium-containing flux, the sintering temperature is lowered, solving the problem of high sintering temperatures in traditional oxide electrolytes. However, the ionic conductivity of oxide electrolytes is low, which cannot meet the high power output requirements of solid-state batteries.

[0004] Publication number CN117691173A reports on the introduction of a polycrystalline oxide electrolyte material with a highly conductive grain boundary phase, which improves the ionic conductivity of the electrolyte material, but does not improve its mechanical properties. During the solid-state battery cycle, solid-solid contact problems still occur, resulting in a decrease in cycle stability. Summary of the Invention

[0005] To solve the above problems, the present invention aims to provide a silicate glass fast ion conductor material and a preparation method. In the present invention, carrier oxides, doping atom oxides and softeners cooperate to break the Si-O-Si bonds in the silicate glass network to form a new bond structure. Halogen atoms, sulfur atoms and nitrogen atoms react with the bridging oxygen (Si-O-Si) in the [SiO4] network to form non-bridging oxygen terminals, significantly reducing the network polymerization degree and the softening point of the material, and regulating the Young's modulus to make its Young's modulus as low as 5-25GPa.

[0006] The present invention is achieved through the following technical solutions:

[0007] A silicate glass fast ion conductor material, the chemical composition of which is A nB m Si e O k M y X q , wherein A is a carrier, including one or more of Li, Na, K, Ag, and Cu; B is a dopant ion in the silicate glass structure, including one or more of P, B, Al, Zn, Ca, Y, In, Zr, Hf, La, Ce, Ti, Sb, Bi, C, Ge, Sn, Pb, and Ga; M is one or more of Ta, Ti, Zr, Hf, V, Nb, Y, In, and Ga; X is one or more of F, Cl, Br, I, O, S, and N; n, m, e, k, y, and q are ratios of the element components, all of which are integers, wherein 0<n≤6, 0≤m≤3, 1≤e≤6, 4≤k≤16, 0≤y≤2, and 0≤q≤4.

[0008] A silicate glass fast ion conductor material, the chemical composition of which is Na2Al2SiO6TaCl5, Na2Al2SiO6ZrCl4, Na2Al2SiO6VCl5 or Na2P2SiO8TaCl5.

[0009] The Young's modulus of silicate glass fast ion conductor material is 5-25GPa.

[0010] It is prepared by softening reaction of carrier oxide, silicate glass, doping atomic oxide and softener; the carrier oxide includes Li2O, Na2O, K2O, Ag2O, CuO; the doping atomic oxide includes one or more of P2O5, B2O3, Al2O3, ZnO, CaO, Y2O3, In2O3, ZrO2, Hf2O5, La2O3, CeO2, TiO2, Sb2O3, Bi2O3, CO, CO2, GeO2, SnO2, Pb2O3, Ga2O3; the softener is one or more of the following four types: halide, halide oxide, nitride with van der Waals crystal structure, sulfide with van der Waals crystal structure; preferably, the carrier oxide, silicate glass, doping atomic oxide and softener are Na2O, SiO2, Al2O3, TaCl5,.

[0011] The molar ratio of the carrier oxide, silicate glass, doping atom oxide and softener is 1-2:1-3:1-5:1-3; preferably, the molar ratio of the four raw materials is 1:1:1:1.

[0012] Silicate glass is a network-forming body having silicon-oxygen bonds Si—O—Si—O—Si.

[0013] The softening reaction is one of a melting method, a hot pressing sintering assisted softening method, and a vapor infiltration method.

[0014] The softening reaction is a melting process, specifically, the raw materials are first melted into a uniform liquid phase, then quenched to obtain amorphous glass, and finally annealed.

[0015] The carrier oxide, silicate glass, doping atom oxide and softener are mixed in appropriate proportions, and softening reaction is carried out by one or more of melting method, hot pressing sintering assisted softening and vapor infiltration method. Preferably, the softening method is melting method.

[0016] The three preparation methods are as follows: the melting method is to mix carrier oxide, silicate glass, dopant atomic oxide and softener in proportion, place them in a platinum crucible or alumina crucible, and heat them in an electric furnace at a rate of 10°C / min to 200-2000°C. The mixture is kept at this temperature for 1-48 hours to completely melt into a uniform liquid phase, followed by rapid quenching (water quenching or copper plate pressing) to obtain amorphous glass, and finally annealing (300-500°C) to eliminate internal stress;

[0017] The hot pressing assisted softening method is to first ball-mill the carrier oxide, silicate glass, doping atom oxide and softener, put them into a mold, place them in a hot pressing furnace, and heat them to 200-2000°C at 5-10°C / min under an inert atmosphere (Ar or N2). At the same time, an axial pressure of 20-100 MPa is applied. The temperature is kept for 1-48 hours to allow halides, oxyhalides and nitrides or sulfides with van der Waals crystal structures to promote particle rearrangement and densification. Then, the mixture is slowly cooled (2-5°C / min) to avoid cracks, and a glass ceramic with a relative density of >95% is obtained.

[0018] The vapor infiltration method involves placing carrier oxides, silicate glass, and doped atom oxides in a tube furnace. Halide, oxyhalide, and nitride or sulfide vapors with a van der Waals crystal structure are introduced at 180-300°C. The carrier gas (Ar) flow rate is controlled at 50-200 mL / min. The infiltration is performed for 2-6 hours to allow the halogen atoms to diffuse into the glass network. Subsequently, an oxidation treatment (with the introduction of O2) at 500-700°C is performed to convert the remaining halides, oxyhalide, and nitride or sulfide with a van der Waals crystal structure into oxides, forming a gradient softening layer. All three methods can produce silicate glass fast ion conductor materials with a network structure.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] The present invention uses carrier oxides, doping atomic oxides, and softeners to synergistically break the Si-O-Si bonds in the silicate glass network to form a new bond structure. Halogen atoms, sulfur atoms, and nitrogen atoms react with the bridging oxygen (Si-O-Si) in the [SiO4] network to form non-bridging oxygen terminals, significantly reducing the network polymerization degree and the softening point of the material, regulating the Young's modulus, improving the mechanical matching with the electrode material, reducing interface cracks, and improving the long-cycle stability of solid-state batteries. The ion migration channel is expanded and the activation energy is reduced, thereby increasing the room temperature ionic conductivity by 1-2 orders of magnitude and meeting the fast charging requirements of solid-state batteries. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0022] Example 1

[0023] The carrier oxide Na₂O, silicate glass SiO₂, dopant atom oxide Al₂O₃, and softener TaCl₅ were mixed in a molar ratio of 1:1:1:1 and heated to 600°C in an electric furnace at a rate of 10°C / min. After melting at 600°C for 3 hours, the mixture was quenched and annealed at 400°C to obtain a softened silicate glass fast ion conductor. Assembly: In an inert gas-protected glove box, a solid-state battery was assembled using NCM as the positive electrode, the softened silicate glass fast ion conductor as the positive electrolyte, Li₂PS₅Cl as the negative electrolyte, and a lithium-indium alloy as the negative electrode.

[0024] The preparation process steps of the softened silicate glass fast ion conductor in Examples 2-4 are the same as those in Example 1, with the only difference being the selection of the doping atomic oxide. See Table 1 for details.

[0025] Table 1. Comparison of the performance of silicate glass fast ion conductors with different doping atoms

[0026]

[0027] The preparation process of the softened silicate glass fast ion conductors in Examples 5-7 is the same as that in Example 1, except that the molar ratios of the carrier oxide Na2O, silicate glass SiO2, doping atom oxide Al2O3, and softener TaCl5 are different. For details, see Table 2. Table 2. Comparison of the performance of silicate glass fast ion conductors with different doping atoms

[0028]

[0029] The softening method and steps of the silicate glass fast ion conductor after softening in Examples 8-13 are the same as those in Example 1, and the only difference is the selection of the softener. See Table 3 for details.

[0030] Table 3. Performance of silicate glass fast ion conductors with different doping atomic oxides

[0031]

[0032] Example 1, Examples 14-15 were prepared using the same raw materials by the melting method, the hot pressing sintering assisted softening method, and the vapor infiltration method, respectively, and the methods are as follows:

[0033] Example 1 Melting method: Carrier oxide, silicate glass, doping atom oxide, and softener are mixed in proportion, placed in a platinum crucible or an alumina crucible, and heated in an electric furnace at a rate of 10°C / min to 600°C (the specific temperature depends on the formulation). The mixture is kept at this temperature for 3 hours to completely melt into a uniform liquid phase, followed by rapid quenching (water quenching or copper plate pressing) to obtain amorphous glass. Finally, the mixture is annealed at 400°C to eliminate internal stress.

[0034] Example 11: A hot pressing sintering assisted softening method comprises first ball-milling a carrier oxide, silicate glass, doping atom oxide, and a softener, placing the mixture into a mold, and placing the mixture in a hot pressing furnace. The mixture is heated to 600° C. at a rate of 5° C. / min under an inert atmosphere (Ar or N2) while applying an axial pressure of 30 MPa. The mixture is kept at this temperature for 3 hours to allow the halides, oxyhalides, and nitrides or sulfides having a van der Waals crystal structure to promote particle rearrangement and densification. The mixture is then slowly cooled (3° C. / min) to avoid cracks, thereby obtaining a glass-ceramic having a relative density greater than 95%.

[0035] Example 12 The vapor infiltration method is to place the carrier oxide, silicate glass, and doped atomic oxide in a tube furnace, and introduce halide, halide oxide, and nitride or sulfide vapor with a van der Waals crystal structure at 240°C, control the carrier gas (Ar) flow rate to 150 mL / min, and infiltrate for 4 hours to allow the halogen atoms to diffuse into the interior of the glass network, and then perform oxidation treatment at 600°C (introducing O2) to convert the residual halide, halide oxide, and nitride or sulfide with a van der Waals crystal structure into oxides to form a gradient softening layer.

[0036] The properties of the fast ion conductors prepared in Examples 1, 11, and 12 are shown in Table 4.

[0037] Table 4. Comparison of silicate glass fast ion conductor performance after softening by different softening methods

[0038]

[0039] It can be seen from Table 4 that when the softening method is the melting method, the softened silicate glass sample has a lower Young's modulus, a higher ionic conductivity, and better cycle stability.

[0040] The softening method and steps of the silicate glass fast ion conductor after softening in Examples 16-18 are the same as those in Example 1, except that the melting temperature is different. For details, see Table 5.

[0041] Table 5. Comparison of fast ion conductor properties of silicate glass after softening at different melting temperatures

[0042]

[0043]

[0044] As can be seen from Table 5, when the melting temperature is 600°C, the softened silicate glass sample has a lower Young's modulus, a higher ionic conductivity, and better cycle stability.

[0045] The softening method and steps of the silicate glass fast ion conductor after softening in Examples 19-21 are the same as those in Example 1, and the only difference is the melting time. See Table 6 for details.

[0046] Table 6. Comparison of fast ion conductor properties of silicate glass after softening at different melting times

[0047]

[0048] It can be seen from Table 6 that when the melting time is 3 h, the softened silicate glass sample has a lower Young's modulus, a higher ionic conductivity, and better cycle stability.

[0049] The Young's modulus of currently reported oxide electrolytes (such as LLZO, LATP, LAGP, etc.) is usually >100 GPa (much higher than sulfide and polymer electrolytes), while the Young's modulus of the present invention is in the range of 5-25 GPa, which is a significant effect.

[0050] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A silicate glass fast ion conductor material, characterized in that: Its chemical composition is A n B m Si e O k M y X q , wherein A is a carrier, including one or more of Li, Na, K, Ag, and Cu; B is a dopant ion in the silicate glass structure, including one or more of P, B, Al, Zn, Ca, Y, In, Zr, Hf, La, Ce, Ti, Sb, Bi, C, Ge, Sn, Pb, and Ga; M is one or more of Ta, Ti, Zr, Hf, V, Nb, Y, In, and Ga; X is one or more of F, Cl, Br, I, O, S, and N; n, m, e, k, y, and q are ratios of the element components, all of which are integers, wherein 0<n≤6, 0≤m≤3, 1≤e≤6, 4≤k≤16, 0≤y≤2, and 0≤q≤8.

2. The silicate glass fast ion conductor material according to claim 1, characterized in that The chemical components are Na2Al2SiO6TaCl5, Na2Al2SiO6ZrCl4, Na2Al2SiO6VCl5 or Na2P2SiO8TaCl5.

3. The silicate glass fast ion conductor material according to claim 1, characterized in that Young's modulus is less than 25GPa.

4. The silicate glass fast ion conductor material according to claim 1, characterized in that It is prepared by softening reaction of carrier oxide, silicate, doping atomic oxide and softener; the carrier oxide includes Li2O, Na2O, K2O, Ag2O, CuO; the doping atomic oxide includes one or more of P2O5, B2O3, Al2O3, ZnO, CaO, Y2O3, In2O3, ZrO2, Hf2O5, La2O3, CeO2, TiO2, Sb2O3, Bi2O3, CO, CO2, GeO2, SnO2, Pb2O3, Ga2O3; the softener is one or more of the following four types: halide, halide oxide, nitride with van der Waals crystal structure, sulfide with van der Waals crystal structure; the silicate includes one or more of orthosilicate and hydrates thereof, orthosilicate and hydrates thereof, hydrated silicate, metasilicate and hydrates thereof.

5. The silicate glass fast ion conductor material according to claim 4, wherein the carrier oxide, silicate, and dopant atom oxide are partially or completely replaced by corresponding metal oxyhalide compounds, halides, and hydroxides to reduce the energy required for their reactions.

6. The silicate glass fast ion conductor material according to claim 5, characterized in that The molar ratio of the carrier oxide, the silicate, the doping atom oxide and the softener is 1-2:1-3:1-5:1-3.

7. The silicate glass fast ion conductor material according to claim 6, characterized in that The molar ratio of the carrier oxide, the silicate, the doping atom oxide and the softener is 1:1:1:

1.

8. The silicate glass fast ion conductor material according to claim 7, characterized in that: The softening reaction is one or a combination of ball milling method, melting method, hot pressing sintering assisted softening, and vapor infiltration method.

9. A solid-state battery, characterized in that: The positive electrode, negative electrode or electrolyte layer of the solid-state battery comprises the silicate glass fast ion conductor material according to any one of claims 1 to 8.

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