Ion conductor, electrode, battery, and electrical device

Abstract

The present application relates to the technical field associated with batteries, and provides an ion conductor, an electrode, a battery, and an electrical device. The ion conductor contains lithium, phosphorus, and sulfur. In an X-ray diffraction pattern using CuKα rays, when the peak intensity of a peak having a 2θ value of 17.9° or more and 19.3° or less is denoted as IA, and the peak intensity of a peak having a 2θ value of 16.5° or more and 17.9° or less is denoted as IB, the following is satisfied: 1.00<IA / IB. The ion conductor provided in the present application has excellent ionic conductivity.

Description

Ion conductor, electrode, battery, and electric device

[0001] Cross Reference to Related Applications

[0002] This application claims priority to the Chinese patent application No. 202411386585.5, filed on September 30, 2024, entitled “An ion conductor, electrode, battery, and electric device”, the whole content of the above application is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application belongs to the technical field of batteries, and specifically relates to an ion conductor, electrode, battery, and electric device. BACKGROUND

[0004] In the currently commercially used lithium ion battery, the electrolyte permeates in the porous structure composed of the electrode and the separator, and forms an efficient ion transmission path between the positive and negative active material particles. In the all-solid-state battery, the electrolyte and the separator are replaced by a solid ion conductor, and the ion conductivity in the solid ion transmission path has a strong influence on the charge and discharge performance of the battery. In addition, since ion transport also occurs at the contact interface between the electrode active material and the solid ion conductor, ion transport occurs through the close contact between the electrode active material and the solid ion conductor. The general electrode active material for practical use is hard, and even if pressure is applied to form an interface with the solid ion conductor, it does not deform. Therefore, the solid ion conductor side must be soft, deformed by pressure molding, and tightly bonded to the surface of the electrode active material. Since the solid ion conductor containing lithium, phosphorus, and sulfur has a softer property than the electrode active material, it is effective as a solid ion conductor used in the all-solid-state battery.

[0005] In addition to this deformability, by having higher ion conductivity, the all-solid-state battery can have equal or better performance than the lithium ion battery using liquid electrolyte. Therefore, the high ion conductivity material in the present application is completed.

[0006]

Non-patent document 1

[0007] SUMMARY

[0008] In the prior art, it is desired to improve the ion conductivity.

[0009] To solve the technical problem, the present application provides an ion conductor containing lithium, phosphorus and sulfur, and when X-ray diffraction is performed using CuKα rays, the relative intensity of a diffraction peak having a 2θ of 17.9° or more and less than 19.3° is defined as I A , and when a diffraction peak having a 2θ of 16.5° or more and less than 17.9° is defined as I B , it is required that 1.00 < I A / I B . BRIEF DESCRIPTION OF DRAWINGS

[0010] To make the technical solutions of the embodiments of the present application clearer, the drawings needed in the embodiments will be briefly introduced below, and it should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope. Other related drawings can also be obtained by those of ordinary skill in the art without making any creative effort on the basis of the drawings.

[0011] FIG. 1 is an XRD pattern of the Li3PS4 product prepared in Example 1, Comparative Example 1 and Comparative Example 2. DETAILED DESCRIPTION

[0012] The following describes the embodiments of the present application.

[0013] To make the technical solutions of the embodiments of the present application clearer, the drawings needed in the embodiments will be briefly introduced below, and it should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope. Other related drawings can also be obtained by those of ordinary skill in the art without making any creative effort on the basis of the drawings.

[0014] The ion conductor in the embodiments disclosed in the present specification contains lithium, phosphorus and sulfur, and when X-ray diffraction is performed using CuKα rays, the relative intensity of a diffraction peak having a 2θ of 17.9° or more and less than 19.3° is defined as I A , and when a diffraction peak having a 2θ of 16.5° or more and less than 17.9° is defined as I B , it is required that 1.00 < I A / I B .

[0015] According to the above structure, an ion conductor with improved ion conductivity can be provided.

[0016] In the prior art, the ion conductivity is not sufficient.

[0017] On the other hand, if it is the structure of the embodiment of the present specification, it is considered that the specific crystal plane of the ion conductor is preferentially oriented, and the ion conductivity is improved. More specifically, according to the XRD pattern, compared with the standard XRD, the ion conductor disclosed in the present specification has a diffraction peak intensity at 2θ of 17.9° or more and less than 19.3° much higher than the normal value, showing preferential orientation of the crystal plane corresponding to 2θ of 17.9° or more and less than 19.3°. This can be related to the solvent used in the present specification, and it can be that the solvent promotes the growth of a specific crystal plane, suppresses the growth of other crystal planes, or both.

[0018] In addition, the relative intensity of the diffraction peak in the present specification indicates the peak height when the background component is removed from the XRD pattern, and does not indicate the integrated area of the diffraction peak.

[0019] In addition, the background of the XRD pattern refers to the scattered light from the device and the signal from the air-tight holder present on the XRD pattern.

[0020] In addition, the ion conductor in the present specification can be a solid electrolyte.

[0021] In addition, the ion conductor in the present specification can actually be free of metal elements other than lithium, and can actually be composed only of lithium, phosphorus, and sulfur.

[0022] Further, the relative intensity of the diffraction peak at 2θ of 17.9° or more and 18.8° or less can be defined as I A , the relative intensity of the diffraction peak at 2θ of 17.0° or more and less than 17.9° can be defined as I B , the relative intensity of the diffraction peak at 2θ = 18.3° ± 0.3° can be defined as I A , the relative intensity of the diffraction peak at 2θ = 17.5° ± 0.3° can be defined as I B .

[0023] In addition, in the ion conductor in the present specification, the I A / I B may be 1.1 ≦ I A / I B may be 1.1 < I A / I B may be 1.2 ≦ I A / I B may be 1.2 < I A / I B may be 1.3 ≦ I A / I B may be 1.3 < I A / I B may be 1.4 ≦ IA / I B , and also can be 1.4 A / I B , and also can be 1.5 A / I B , and also can be 1.5 A / I B .

[0024] By the above structure, the ion conductor has a specific crystal plane preferred orientation, and the ion conductivity is further improved.

[0025] In addition, in the present application, the relationship between the relative intensity of the diffraction peak a and the diffraction peak b is IA / IB>1.00, IA / IB>1.10, IA / IB>1.20, IA / IB>1.30, IA / IB>1.40, IA / IB>1.50 or more, and in addition, all ranges and sub-ranges between the above values can also be satisfied. It should be understood that in one embodiment, any range can be combined with any other range. A / I B 1.10, IA / IB>1.20, IA / IB>1.30, IA / IB>1.40, IA / IB>1.50 or more, and in addition, all ranges and sub-ranges between the above values can also be satisfied. It should be understood that in one embodiment, any range can be combined with any other range. A / I B 1.20, IA / IB>1.30, IA / IB>1.40, IA / IB>1.50 or more, and in addition, all ranges and sub-ranges between the above values can also be satisfied. It should be understood that in one embodiment, any range can be combined with any other range. A / I B 1.30, IA / IB>1.40, IA / IB>1.50 or more, and in addition, all ranges and sub-ranges between the above values can also be satisfied. It should be understood that in one embodiment, any range can be combined with any other range. A / I B 1.40, IA / IB>1.50 or more, and in addition, all ranges and sub-ranges between the above values can also be satisfied. It should be understood that in one embodiment, any range can be combined with any other range. A / I B 1.50 or more, and in addition, all ranges and sub-ranges between the above values can also be satisfied. It should be understood that in one embodiment, any range can be combined with any other range.

[0026] In addition, in the ion conductor in the present specification, the molar ratio of Li:P:S=x:y:z can be such that x is 2.5≦x≦3.5, y is 0.5≦y≦1.5, and z is 3.5≦z≦4.5.

[0027] By the above structure, the ion conductor has a specific crystal plane preferred orientation, and the ion conductivity is further improved.

[0028] In addition, in the ion conductor in the present specification, x can be x=3, y can be y=1, and z can be z=4.

[0029] By the above structure, the ion conductor has a specific crystal plane preferred orientation, and the ion conductivity is further improved.

[0030] In addition, in the ion conductor in the present specification, the ion conductivity at room temperature can be 0.1 mS / cm or more.

[0031] By the above structure, the ion conductor has a specific crystal plane preferred orientation, and the ion conductivity is further improved.

[0032] In addition, room temperature is, for example, 25°C.

[0033] In addition, in the present specification, the ionic conductivity is measured while applying a pressure of 690 MPa.

[0034] In addition, the average particle diameter of the ion conductor in the present specification can be 0.1 to 100 μm, or 0.1 to 10 μm.

[0035] According to the above configuration, the battery using the ion conductor in the present specification is more easily densified, and the performance (e.g., energy density) of the battery can be further improved.

[0036] In addition, the average particle diameter is measured by observing ion conductor particles, measuring the longest diameter L of any 10 particles respectively, and averaging the measurement values.

[0037] In addition, the average particle diameter is more preferably 1 to 3 μm.

[0038] In addition, the average particle diameter in the present specification is calculated based on the particle diameter after firing and pulverization.

[0039] In addition, the average particle diameter can be calculated by SEM observation. In the SEM observation, a product manufactured by Hitachi High-Technologies Corporation, product name "SU8000 Type II" (or a product equivalent thereto) can be used. In addition, the ion conductor in the present specification can have a peak attributed to Li3PS4in CuKα ray X-ray diffraction.

[0040] The ionic conductivity is further improved by the above configuration.

[0041] In addition, having a peak attributed to Li3PS4indicates that, for example, in an XRD pattern, a diffraction peak can be present at 2θ = 30.0° ± 0.3°, 29.3° ± 0.3°.

[0042] In addition, the peak intensity at 2θ = 30.0° ± 0.3° is set to I C , and the peak intensity at 2θ = 29.3° ± 0.3° is set to I D , it can be 1.09 < I A / I C , and it can be 0.75 < I A / I D .

[0043] By configuring 1.09 < I A / I C , the ion conductor has a specific crystal plane preferred orientation, and the ionic conductivity is further improved.

[0044] By configuring 0.75 < I A / I DThe ion conductor has a specific crystal plane preferred orientation, and the ion conductivity is further improved.

[0045] In addition, I A / I C may be 1.1≦I A / I C may be 1.1<I A / I C may be 1.2≦I A / I C may be 1.2<I A / I C may be 1.3≦I A / I C may be 1.3<I A / I C .

[0046] In addition, I A / I D may be 0.8<I A / I D may be 0.8≦I A / I D may be 0.9<I A / I D may be 0.9≦I A / I D may be 1.0<I A / I D may be 1.0≦I A / I D may be 1.1<I A / I D may be 1.1≦I A / I D may be 1.2<I A / I D may be 1.2≦I A / I D .

[0047] The ion conductor has a specific crystal plane preferred orientation, and the ion conductivity is further improved.

[0048] In addition, I D >I C .

[0049] In a second aspect, the application further provides a battery comprising the ion conductor provided in the first aspect.

[0050] In a third aspect, the present application also provides an electrical device comprising the ion conductor of the second aspect. The battery comprises the ion conductor of the first aspect.

[0051] The electrical device can be any electrical device that can use a lithium ion solid-state battery, such as an electric vehicle, an aircraft, a ship, a mobile phone, a tablet computer, a portable game console, a portable digital device (e.g., a digital camera), a smart home, a smart wearable (e.g., a smart bracelet, a smart watch, smart glasses), etc.

[0052] [Method for manufacturing the ion conductor]

[0053] The ion conductor of the present application can be prepared by dispersing raw materials containing Li, P, and S into a solvent to obtain a suspension, then mixing, drying, and heat treating the suspension.

[0054] The solvent used in preparing the suspension can be one or two or more of an ester-based solvent, a hydrocarbon-based solvent, and an organic sulfur compound. The ester-based solvent can be one or two or more of ethyl acetate, butyl acetate, etc. The hydrocarbon-based solvent can be one or two or more of petroleum ether, cyclohexane, n-hexane, heptane, etc. The organic sulfur compound can be one or two or more of carbon disulfide, dimethyl sulfoxide, ethyl mercapto, etc. The amount of the solvent used is not particularly limited, as long as it can be mixed with the raw materials to form a solution or a suspension.

[0055] In addition, the solvent used in adjusting the suspension is preferably a solvent having a Hansen solubility parameter (hereinafter referred to as "HSP") "δ" of 17 to 19. Here, the HSP refers to the decomposition of Hildebrand's solubility parameter into three components of the polymerization energy: London dispersion force, dipole force, and hydrogen bond force, and is the basis as a vector. The component corresponding to the London dispersion force of the HSP is the dispersion term "δ d ", the component corresponding to the dipole force is the polarity term "δ", and the component corresponding to the hydrogen bond force is the hydrogen bond term "δ h". Since HSP is a vector, there are almost no pure substances that have exactly the same values. In addition, databases have been established for the HSP of commonly used substances. Therefore, for practitioners, the HSP values of the required substances can be obtained by referring to the database. Even if the HSP values of certain substances are not registered in the database, practitioners can calculate the HSP values according to the chemical structure of the substance using computer software such as Hansen Solubility Parameters in Practice (HSPiP). For a mixture composed of multiple substances, the sum of the volume ratio products of the components and the entire mixture can be calculated. For more information on HSP, please refer to Hiroshi Yamamoto, S. Abbott and C. M. Hansen, Chemical Industry, March 2010.

[0056] The drying process can include reduced pressure drying and vacuum drying. For example, reduced pressure drying is drying performed under a relative vacuum degree of -0.01 to -0.1 MPa, and vacuum drying refers to drying at a relative vacuum degree of less than -0.1 MPa. Note that each of the reduced pressure drying and the vacuum drying can be continued for 0.5 to 48 hours.

[0057] The heat treatment temperature of the heat treatment process can be selected in the range of 50°C to 300°C, and more preferably between 100°C and 200°C. At a temperature above 50°C, the heat treatment effect is more pronounced, and can effectively improve the performance of the ion conductor. On the other hand, below 300°C, it is difficult to affect the structure of the ion conductor, and it is also unlikely to affect its performance. The method of heat treatment is not particularly limited, and conventional heating methods can be generally used, such as hot air, hot water, steam, electric heating, microwave heating, vacuum heat treatment, pressure heat treatment, etc.

[0058] Compared with the XRD pattern of the conventional technology, the XRD pattern of the ion conductor of the present application has a diffraction peak intensity at 2θ = 18.3° ± 0.3° much higher than the normal value, and shows a preferred orientation of the crystal plane corresponding to 2θ = 18.3° ± 0.3°. This structural feature can help to improve the ionic conductivity and other related properties of the LPS ion conductor. This may be related to the solvent used in the present application, which is speculated to promote the growth of a specific crystal plane, inhibit the growth of other crystal planes, or both.

[0059] In order for those skilled in the art to better understand the innovations of the present application, the present specification will be described in detail below in conjunction with the examples. The examples of the present specification described below are exemplary and are only used to explain the present application and cannot be understood as a limitation of the present application.

[0060] Examples

[0061] Preparation of Li3PS4 ion conductor

[0062] Example 1

[0063] In a glove box, lithium sulfide and phosphorus pentasulfide were weighed in a molar ratio of 3:1, and mixed with an appropriate amount of an ester solvent having a value of δ of 17 to 19 to obtain a suspension. Then, ceramic balls and the suspension were put in a reaction vessel. The ceramic balls were rotated and driven by a rotating shaft in the vessel to cause the reaction of the raw materials. The suspension after the reaction was taken out, and centrifuged to separate a solid component, i.e., a precipitate, and a liquid component.

[0064] The obtained precipitate was subjected to 12 hours of drying under reduced pressure, and then to 3 hours of vacuum drying to obtain a precursor powder of the ion conductor.

[0065] The precursor powder was subjected to heat treatment at 170°C for 1 hour, and then the product was pulverized to obtain a Li3PS4 ion conductor.

[0066] Comparative Example 1

[0067] An ion conductor was prepared in the same manner as in Example 1 except that the solvent was changed to a solvent having a higher value of δ than the solvent used in Example 1.

[0068] Comparative Example 2

[0069] An ion conductor was prepared in the same manner as in Example 1 except that the solvent was changed to acetonitrile.

[0070] XRD measurement

[0071] In order to identify the ion conductors obtained in the examples and comparative examples, and to calculate the relative intensity ratio of the diffraction peaks, XRD measurement was performed. The ion conductor powders obtained in the examples and comparative examples were uniformly filled into a groove having a diameter of 20 mm and a depth of 0.2 mm, and used as a sample after being ground with a glass. Then, the sample was sealed with a film for XRD to avoid contact with air, and measurement was performed under the following conditions.

[0072] Measurement device: MiniFlex600, manufacturer: RIGAKU

[0073] Tube voltage: 40 kV

[0074] Tube current: 15 mA

[0075] X-ray wavelength: Cu-Kα ray (wavelength )

[0076] Beam slit structure: Sollar slit 2.5°

[0077] Detector: D / teX Ultra2

[0078] Measurement range: 2 theta = 10 - 70 deg

[0079] Step width, scan speed: 0.02 deg, 2.000 deg / sec

[0080] Fig. 1 shows the XRD pattern of Example 1 obtained by the measurement described above.

[0081] The diffraction peak at 2 theta = 18.3° ± 0.3° in the obtained XRD pattern was defined as diffraction peak A, and the diffraction peak at 2 theta = 17.5° ± 0.3° was defined as diffraction peak B. By comparing the relative intensities of the respective diffraction peaks, I A / I B .

[0082] In addition, by comparing the obtained XRD pattern with the data of ICSD 180318, it was determined whether Li3PS4was being produced.

[0083] Ion conductivity measurement

[0084] The ion conductor obtained in the examples and comparative examples was used as a molded sample in the form of a circular pellet having a diameter of 6 to 20 mm (cross-sectional area S: 0.283 to 3.14 cm 2 ), and a height (L) of 0.1 to 1.0 cm. Electrode terminals were taken out from the upper and lower parts of the sample, and measurement was performed using an alternating current impedance method under conditions of 690 MPa and 25°C (frequency range: 1 MHz to 0.1 Hz, amplitude: 10 mV) to obtain a Cole-Cole curve. In the vicinity of the right end of the circular arc observed in the high frequency region, the real part Z'(Ω) of the point at which -Z"(Ω) was the minimum was taken as the bulk resistance R(Ω) of the electrolyte, and the ion conductivity σ (S / cm) was calculated according to the following formula. The calculation of the ion conductivity of the ion conductor obtained in the examples and comparative examples is shown in Table 1. The measurement device used was SP150e manufactured by Biologic.

[0085] R = p (L / S)

[0086] σ = 1 / p

[0087] Table 1

[0088] <CONCLUSION>

[0089] From the above results, I A / I B is greater than 1.00, an increase in ion conductivity can be observed. From this, it is inferred that the specific crystal plane of the ion conductor has a preferred orientation, which contributes to an increase in ion conductivity.

[0090] The above merely describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims. Industrial applicability

[0091] The present application provides an ion conductor, an electrode, a battery, and an electric device, which can effectively improve the ion conductivity and other related properties of the ion conductor.

[0092] In addition, it can be understood that the ion conductor, the electrode, the battery, and the electric device of the present application are reproducible and can be widely applied to the technical field of batteries.

Claims

1. An ion conductor comprising lithium, phosphorus and sulfur, wherein, In X-ray diffraction using CuKα rays, the relative intensity of a diffraction peak having a 2θ of 17.9° or more and less than 19.3° is defined as I A The relative degree of a diffraction peak having a 2θ of 16.5° or more and less than 17.9° is defined as I B When I A / I B is 1.00 or more, 1.00 2. The ion conductor of claim 1, wherein, The I A / I B 1.20 ≦ I A / I B .

3. The ion conductor of claim 2, wherein, The I A / I B 1.50 ≦ I A / I B .

4. The ion conductor of claim 1, wherein, In the X-ray diffraction pattern using CuKα rays, a diffraction peak C is also present in the range of 2θ = 30.0° ± 0.3°, and a diffraction peak D is also present in the range of 2θ = 29.3° ± 0.3°; wherein the relative intensity of diffraction peak C is defined as I C / I D C, and the relative intensity of diffraction peak D is defined as I A / I C > 1.09, or I A / I D > 0.75, or I A / I C > 1.09 and I A / I D > 0.

75.

5. The ion conductor of claim 4, wherein, I A / I C > 1.30, or I A / I D > 1.20, or I A / I C > 1.30 and I A / I D > 1.

20.

6. The ion conductor of claim 4 or claim 5, wherein, I D > I C .

7. The ion conductor according to claim 1, wherein the molar ratio of Li:P:S = x:y:z; said x is 2.5 ≦ x ≦ 3.5, said y is 0.5 ≦ y ≦ 1.5, and said z is 3.5 ≦ z ≦ 4.

5.

8. The ion conductor of claim 7, wherein, said x is x = 3, said y is y = 1, and said z is z = 4.

9. The ion conductor of claim 1, wherein, The ion conductivity is 0.1 mS / cm or more at room temperature.

10. The ion conductor of claim 1, wherein, In the x-ray diffraction using CuKα rays, peaks attributed to Li3PS4 are present.

11. An electrode comprising the ion conductor according to any one of claims 1 to 10.

12. A battery comprising the ion conductor according to any one of claims 1 to 10.

13. An electric device comprising the battery according to claim 12.

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