solid electrolyte particles

Abstract

To improve oxidation resistance.SOLUTION: A solid electrolyte particle includes Li, Ge, P, and S. The solid electrolyte particle satisfies relationships of 0.20≤IB / IA≤0.35 and 0.30≤IC / IA≤0.45. IA, IB, and IC each indicate a peak height in an X-ray diffraction spectrum measured using a CuKα ray as an X-ray source. IA indicates a peak height at a diffraction angle of 29.4±0.5°. IB indicates a peak height at a diffraction angle of 41.4±0.5°. IC indicates a peak height at a diffraction angle of 47.3±0.5°.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to solid electrolyte particles. [Background technology]

[0002] WO 2017 / 155119 discloses a sulfide solid electrolyte. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 155119 Summary of the Invention [Problem to be solved by the invention]

[0004] Solid electrolytes are the key materials for all-solid-state batteries. Conventionally, sulfide solid electrolytes containing Li, P, and S have been developed. -3 Sulfide solid electrolytes can have high ionic conductivity on the order of S / cm. However, sulfide solid electrolytes tend to have low oxidation resistance. When sulfide solid electrolytes undergo oxidative decomposition, polysulfides can be formed. The formation of polysulfides can reduce ionic conductivity.

[0005] The positive electrode has a high potential. In the positive electrode, the sulfide solid electrolyte may be oxidized and decomposed, resulting in the formation of a resistive layer (polysulfide) at the interface between the positive electrode active material and the sulfide solid electrolyte. -10 The formation of a resistive layer may accelerate the degradation of the performance of solid-state batteries.

[0006] The objective of the present disclosure is to improve oxidation resistance. [Means for solving the problem]

[0007] 1. A solid electrolyte particle according to one aspect of the present disclosure has the following composition: The solid electrolyte particle contains Li, Ge, P, and S. The solid electrolyte particle satisfies the relationship of the following formula (1) and formula (2). 0.20≦I B / I A ≦0.35 …(1) 0.30≦I C / I A ≦0.45 …(2) In the above formula (1) and formula (2), I A , I B and I C and indicate the peak heights in the X-ray diffraction spectrum measured using CuKα radiation as the X-ray source. A indicates the peak height at a diffraction angle of 29.4±0.5°. B indicates the peak height at a diffraction angle of 41.4±0.5°. C indicates the peak height at a diffraction angle of 47.3±0.5°.

[0008] In the X-ray diffraction (XRD) spectrum of the solid electrolyte particles, the peaks appearing at diffraction angles (2θ) of 29.4±0.5°, 41.4±0.5°, and 47.3±0.5° are believed to belong to the LGPS-type crystalline phase. The LGPS-type crystalline phase can have high ionic conductivity. B / I A , I C / I A ) is an index of crystallinity. B / I A , I C / I A ) indicates lower crystallinity. According to the new findings of the present disclosure, an improvement in oxidation resistance is expected due to a moderately low crystallinity. However, if the crystallinity is excessively reduced, the oxidation resistance may actually decrease. In other words, when the relationship of the above formula (1) and formula (2) is satisfied, an improvement in oxidation resistance is expected.

[0009] 2. The solid electrolyte particles described in the above item "1" may have the following configuration: In an X-ray diffraction spectrum, the peak at a diffraction angle of 29.4±0.5° has a full width at half maximum of 0.15° or less.

[0010] When the peak at a diffraction angle of 29.4±0.5° has a full width at half maximum (FWHM) of 0.15° or less, both high ionic conductivity and oxidation resistance are expected.

[0011] 3. The solid electrolyte particles according to the above item "1" or "2" may have the following configuration: The solid electrolyte particles further satisfy the relationship of the following formula (3). 1.2≦I E / I D …(3) In the above formula (3), I D and I E and I respectively indicate the peak height in the Raman spectrum. D is 420±10cm -1 The peak heights at the Raman shifts of I E is 360±10cm -1 The Raman spectrum shows the peak height at the Raman shift of 388 ± 3 cm -1 It has a shoulder peak at the Raman shift of

[0012] In the Raman spectrum of solid electrolyte particles, 388±3 cm -1 The shoulder peak that appears in the Raman shift of is thought to be due to impurity phases such as Li2S. The impurity phase is thought to be generated by oxidative decomposition of the LGPS-type crystal phase. In other words, the impurity phase is the cause of the decrease in crystallinity. When the solid electrolyte particles satisfy the relationship of the above formula (3), it is thought that the crystallinity in the bulk is maintained. By locally introducing the impurity phase while maintaining the bulk crystallinity, it is expected that both high ionic conductivity and oxidation resistance can be achieved.

[0013] 4. The solid electrolyte particle according to any one of the above items "1" to "3" may have the following configuration. The solid electrolyte particle includes a core portion and a shell portion. The shell portion surrounds the core portion. The core portion includes an LGPS-type crystalline phase. The shell portion includes an amorphous phase. The core portion has a particle size of 10×10 -3 The shell has an ionic conductivity of 1×10 S / cm or more. -3 It has an ionic conductivity of less than S / cm.

[0014] For example, the crystallinity may be locally reduced at the outermost surface of the particle. The solid electrolyte particle may have, for example, a core-shell structure. The LGPS-type crystalline phase tends to have high ionic conductivity and low oxidation resistance. The amorphous phase tends to have low ionic conductivity and high oxidation resistance. When the core portion contains the LGPS-type crystalline phase and the shell portion (outermost surface) contains the amorphous phase, both high ionic conductivity and oxidation resistance are expected to be achieved.

[0015] 5. The solid electrolyte particle described in the above item "4" may include, for example, the following configuration: The shell portion has a thickness of 100 nm or less.

[0016] By making the shell (amorphous phase) 100 nm thick, it is expected that both high ionic conductivity and oxidation resistance can be achieved.

[0017] Hereinafter, an embodiment of the present disclosure (hereinafter may be abbreviated as "the present embodiment") and an example of the present disclosure (hereinafter may be abbreviated as "the present example") will be described. However, the present embodiment and the example do not limit the technical scope of the present disclosure. The present embodiment and the example are illustrative in all respects. The present embodiment and the example are non-restrictive. The technical scope of the present disclosure encompasses all modifications within the meaning and scope equivalent to the claims. For example, it is originally intended that any configuration may be extracted from the present embodiment and the example and that they may be arbitrarily combined. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is an example of an XRD spectrum. [Figure 2] FIG. 2 is an example of a Raman spectrum. [Figure 3] FIG. 3 is an example of a cyclic voltammogram. [Figure 4] FIG. 4 is a conceptual diagram of the core-shell structure. [Figure 5] FIG. 5 is a schematic flowchart of a method for producing solid electrolyte particles in this embodiment. [Figure 6] FIG. 6 is a table showing the experimental results. DETAILED DESCRIPTION OF THE INVENTION

[0019] <Terminology> The "XRD spectrum" is measured by powder XRD. The measurement conditions are as follows. However, the measurement device is an example, and an equivalent device may also be used. Measuring device: Product name "RINT-2000", manufactured by Rigaku Corporation X-ray source: Cu-Kα ray Angle range: 2θ=10~60°

[0020] Peak height ratio (I B / I A , I C / I A ) is determined by the following procedure. The background is removed from the raw data of the XRD spectrum. After the background is removed, the XRD spectrum is normalized by setting the height of the peak appearing at a diffraction angle of 29.4±0.5° as "1". In the normalized XRD spectrum, the peak height at a diffraction angle of 41.4±0.5° is determined as the peak height ratio (I B / I A Similarly, in the normalized XRD spectrum, the peak height at a diffraction angle of 47.3±0.5° is considered to be the peak height ratio (I C / I A) Note that, for example, if multiple peaks exist within a range such as 29.4±0.5°, the height of the highest peak is measured. Furthermore, the FWHM of the peak at a diffraction angle of 29.4±0.5° is measured.

[0021] The "Raman spectrum" is measured by Raman spectroscopy. The measurement conditions are as follows. However, the measurement device is an example, and an equivalent device may also be used. Measuring device: Product name "LabRAM HR", manufactured by Horiba Ltd. Laser wavelength: 532nm Grating: 1200 Wavenumber range: 200-2000cm -1

[0022] Peak height ratio (I E / I D ) is determined by the following procedure: 460~500cm -1 The average Raman intensity in the range of 420±10cm is taken as the reference intensity. -1 The difference between the peak top Raman intensity and the reference intensity in the Raman shift of D ) is considered to be 360±10cm -1 The difference between the peak top Raman intensity and the reference intensity in the Raman shift of E ) is considered as the peak height (I E ) is the peak height (I D ) to obtain the peak height ratio (I E / I D ) is obtained.

[0023] "LGPS-type crystalline phase" refers to a crystalline phase having an LGPS-type structure. The LGPS-type structure includes a three-dimensional framework. The three-dimensional framework includes a plurality of one-dimensional chains. Each one-dimensional chain is composed of (Ge 0.5 P 0.5It is formed by one-dimensionally connecting LiS4 tetrahedra and LiS6 octahedra, sharing edges. Two adjacent one-dimensional chains are connected through a PS4 tetrahedron. In the LGPS structure, P atoms can occupy the 4d site and the 2b site. The 4d site constitutes the one-dimensional chain. The 2b site constitutes the link connecting the one-dimensional chains. The 4d site can be occupied by Ge atoms and P atoms. The molar ratio of Ge / P in the 4d site is "1 / 1". The 2b site can be occupied only by P atoms. The XRD spectrum of the LGPS crystalline phase has peaks at diffraction angles (2θ) of 29.4±0.5°, 41.4±0.5°, and 47.3±0.5°.

[0024] Unless otherwise specified, numerical ranges such as "m to n%" include the upper and lower limits. That is, "m to n%" indicates a numerical range of "m% or more and n% or less." "m% or more and n% or less" includes "more than m% but less than n%."

[0025] The terms "comprise," "include," "have," and variations thereof (e.g., "consisting of") are open-ended terms. Open-ended terms may or may not include additional elements in addition to the required elements. The term "consisting of" is a closed term. However, even closed terms do not exclude additional elements that are normally associated impurities or that are unrelated to the disclosed technology. The term "consisting essentially of..." is a semi-closed term. Semi-closed terms allow for the addition of elements that do not substantially affect the basic and novel characteristics of the disclosed technology.

[0026] Elements expressed in the singular include the plural unless otherwise specified. For example, "particle" includes not only "one particle" but also "plural particles (particle group)" and "aggregate of particles (powder)."

[0027] The stoichiometric composition formula indicates a representative example of a compound. The compound may have a non-stoichiometric composition. For example, "Al2O3" is not limited to a compound having a molar ratio of "Al / O=2 / 3". Unless otherwise specified, "Al2O3" indicates a compound containing Al and O in any molar ratio. Furthermore, for example, the compound may be doped with a trace element. A portion of Al and O may be substituted with another element.

[0028] <Solid electrolyte particles> The solid electrolyte particles are Li-ion conductors. The solid electrolyte particles may be, for example, for an all-solid-state battery. The solid electrolyte particles may be, for example, for a positive electrode, a negative electrode, or a separator. The D50 of the solid electrolyte particles may be, for example, any of 0.01 to 10 μm, 0.01 to 1 μm, or 0.1 to 1 μm. "D50" refers to the particle size at which the cumulative total is 50% in the volume-based particle size distribution (cumulative distribution). The particle size distribution can be measured by laser diffraction.

[0029] The solid electrolyte particles contain, as chemical components, Li (lithium), Ge (germanium), P (phosphorus), and S (sulfur). The solid electrolyte particles may have, for example, a bulk composition represented by the following formula (4): Li 10+x Ge 1+x P 2-x S 12 (0≦x≦0.7) …(4) In the above formula (4), x may be, for example, 0.5 or less, 0.3 or less, or 0.1 or less.

[0030] <XRDスペクトル> Figure 1 shows an example of an XRD spectrum. Solid electrolyte particles have a specific XRD spectrum. The peak height ratio (I B / I A ) is 0.20 to 0.35. In this range, improvement in oxidation resistance is expected. B / I A ) may be, for example, 0.31 or less. B / IA ) may be, for example, 0.29 or more.

[0031] Peak height ratio (I C / I A ) is 0.30 to 0.45. In this range, improvement in oxidation resistance is expected. C / I A ) may be, for example, 0.44 or less or 0.43 or less. C / I A ) may be, for example, 0.42 or greater or 0.43 or greater.

[0032] The FWHM at the peak at a diffraction angle of 29.4±0.5° may be, for example, 0.15° or less, 0.14° or less, or 0.13° or more.

[0033] <Raman spectrum> Figure 2 shows an example of a Raman spectrum. The solid electrolyte particles may have a specific Raman spectrum. The Raman spectrum is at 388±3 cm -1 The Raman shift of the SiO2 film may have a shoulder peak. The shoulder peak is thought to be derived from an impurity phase (Li2S, etc.). The presence of an appropriate amount of the impurity phase is expected to improve oxidation resistance.

[0034] Peak height ratio (I E / I D ) may be, for example, 1.2 or more. E / I D When the peak height ratio (I) is 1.2 or more, it is considered that the change in bulk crystallinity is small. A small change in bulk crystallinity is expected to result in high ionic conductivity. E / I D ) may be, for example, 1.30 or more or 1.35 or more. E / I D ) may be, for example, 1.40 or less or 1.35 or less.

[0035] <Cyclic voltammetry> FIG. 3 is an example of a cyclic voltammogram. Oxidation resistance can be evaluated by cyclic voltammetry (CV). The smaller the maximum value of the oxidation current (hereinafter also referred to as "maximum current") in the cyclic voltammogram (current-potential curve), the better the oxidation resistance is considered to be. The solid electrolyte particles may have a maximum current of, for example, 20 μA or less. The maximum current may be, for example, 11 μA or less, or 7 μA or less. The maximum current may be, for example, 1 μA or more, 3 μA or more, or 7 μA or more.

[0036] The cyclic voltammogram may have a peak (maximum value) on the oxidation side. The cyclic voltammogram does not have to have a peak on the oxidation side. When there is no peak on the oxidation side, improvement in oxidation resistance is expected.

[0037] The CV is measured using a half cell. The half cell includes a working electrode and a counter electrode. The counter electrode is Li metal. The working electrode is prepared as follows: A sample (solid electrolyte particles) is compressed to form a first pellet (green compact). A mixture is prepared by mixing the sample with vapor-grown carbon fiber (VGCF). The mixing ratio is "sample / VGCF = 1 / 1 (volume ratio)." The first pellet serves as a substrate, and the mixture is compressed on the substrate to form a second pellet. The working electrode is a stack of the first pellet and the second pellet. The second pellet is pressed onto the first pellet. It is believed that the presence of a conductive material (VGCF) in the working electrode allows for the observation of oxidation reactions that may occur in an actual electrode.

[0038] The conditions for measuring CV are as follows. However, the measuring device is an example, and an equivalent device may also be used. Measurement device: Product name "VMP3", manufactured by BioLogic Sweep speed: 0.1mV / s Sweep potential range: 2.5 to 4.8 V (vs. Li / Li + )

[0039] <AC impedance> The solid electrolyte particles can have high ionic conductivity. For example, the solid electrolyte particles can have a density of 3.0×10 -3 The ionic conductivity may be, for example, 4.5×10 S / cm or more. -3 S / cm or more, or 5.0 x 10 -3 The ionic conductivity may be, for example, 5.5×10 S / cm or more. -3 S / cm or less, or 5.0 x 10 -3 S / cm or less is acceptable.

[0040] The ionic conductivity is measured by an AC impedance method. Solid electrolyte particles (powder) are compressed to form a pellet. The pellet is sandwiched between non-activated electrodes to form a symmetric cell. The non-activated electrode and the solid electrolyte particles have different carrier ions. The non-activated electrode may include, for example, stainless steel. The ionic conductivity is measured in the symmetric cell. The measurement conditions are as follows. However, the measurement device is an example, and an equivalent device may also be used. Measurement device: Product name "VMP3", manufactured by BioLogic Frequency range: 1MHz to 0.1Hz Applied voltage: 10mV Measurement temperature: 25±1℃

[0041] The measured data is plotted on a complex plane to create a Cole-Cole plot. The resistance is calculated from the intersection of the curve with the real axis. The ionic conductivity is calculated using the following equation (5). σ=1 / {(r×s) / t} …(5) σ: ionic conductivity r: resistance s: area of ​​the working electrode t: thickness of the working electrode

[0042] <Core-shell structure> 4 is a conceptual diagram of a core-shell structure. The solid electrolyte particle 10 may have, for example, a core-shell structure. That is, the solid electrolyte particle 10 may include a core portion 11 and a shell portion 12.

[0043] The core 11 includes a highly ion-conductive phase. The core 11 may include, for example, an LGPS-type crystalline phase. The core 11 may include, for example, a 10×10 -3 The ionic conductivity of the core portion 11 may be, for example, 15×10 S / cm or more. -3 S / cm or more, or 20 x 10 -3 The ionic conductivity of the core portion 11 may be, for example, 20×10 -3 S / cm or less, or 15 x 10 -3 The core region 11 may have a Feret diameter of, for example, 0.1 to 1 μm. The "Feret diameter" refers to the distance between the two most distant points on the contour line of the core region 11 in a cross-sectional image of the solid electrolyte particle 10.

[0044] The shell portion 12 covers the periphery of the core portion 11. The shell portion 12 may cover the entire core portion 11. The shell portion 12 may cover a part of the core portion 11. The shell portion 12 includes a low ion conductive phase. The shell portion 12 may have oxidation resistance. The shell portion 12 may have, for example, lower crystallinity than the core portion 11. The shell portion 12 may include, for example, an amorphous phase. The shell portion 12 may have, for example, a crystallinity of 1×10 -3 The ionic conductivity of the shell portion 12 may be, for example, 0.5×10 S / cm or less. -3 S / cm or less, or 0.1 x 10 -3 The ionic conductivity of the shell portion 12 may be, for example, 0.1×10 S / cm or less. -3 S / cm or more, or 0.5 x 10 -3The shell portion 12 may have a thickness of, for example, 100 nm or less. The shell portion 12 may have a thickness of, for example, 50 nm or less, or 10 nm or less. The shell portion 12 may have a thickness of, for example, 1 nm or more, 10 nm or more, or 50 nm or more.

[0045] <Method of manufacturing solid electrolyte particles> 5 is a schematic flowchart of a method for producing solid electrolyte particles according to this embodiment. Hereinafter, the "method for producing solid electrolyte particles according to this embodiment" may be abbreviated as "the present production method." The present production method includes "(a) synthesis of solid electrolyte particles" and "(b) surface treatment."

[0046] (a) Synthesis of solid electrolyte particles The manufacturing method includes synthesizing solid electrolyte particles. The solid electrolyte particles may be synthesized, for example, by a solid-state reaction. The solid electrolyte particles may be synthesized, for example, by a mechanochemical reaction. The solid electrolyte particles are synthesized to include an LGPS-type crystalline phase. For example, Li2S, P2S5, and GeS2 are mixed in a predetermined ratio to form a mixture. For example, the mixing may be performed using a planetary ball mill. The mixing may be performed in an Ar atmosphere. The solid electrolyte particles can be synthesized by subjecting the mixture to heat treatment (calcination).

[0047] (b) Surface treatment The present manufacturing method includes reducing the crystallinity of at least a portion of the surface of a solid electrolyte particle. For example, a damaged layer may be formed by applying mechanical energy to the surface of the particle. The damaged layer has low crystallinity relative to the base material. The damaged layer can form the shell portion 12 of a core-shell structure. The base material excluding the damaged layer can form the core portion 11 of the core-shell structure.

[0048] For example, the solid electrolyte particles may be subjected to a wet milling process. For example, the solid electrolyte particles may be pulverized in the presence of a solvent using a planetary ball mill. The solvent may include, for example, at least one selected from the group consisting of butyl butyrate, heptane, and tetralin. After the wet milling process, the solvent may be removed by drying.

[0049] For example, media (grinding balls) made of ZrO2 may be used. The rotation speed of the planetary ball mill may be, for example, 200 to 250 rpm. The treatment time may be, for example, 1 hour or more. The treatment time may be, for example, 24 hours or less. [Example]

[0050] <Sample> 6 is a table showing the experimental results. Solid electrolyte particles No. 1 to No. 6 were produced according to the following procedure.

[0051] No.1 A first mixture was prepared by mixing 3.902 parts by mass of Li2S, 3.775 parts by mass of P2S5, and 2.323 parts by mass of GeS in a mortar until the mixture was substantially uniform. A first pot (material: ZrO2, volume: 500 mL) and first media (material: ZrO2, diameter: 5 mm) for a planetary ball mill were prepared. 450 parts by mass of the first media and the first mixture were added to the first pot. Dry milling was performed at a rotation speed of 300 rpm for 20 hours. This resulted in a second mixture. The second mixture was formed into pellets. The pellets were sealed in quartz tubes. The quartz tubes were coated with carbon. The pellets were heat-treated at 600°C for 6 hours. This resulted in the synthesis of a solid electrolyte. After the heat treatment, the pellets were pulverized, and solid electrolyte particles were collected.

[0052] A second pot (material: ZrO2, volume: 45 mL), second media (material: ZrO2, diameter: 1 mm), and third media (material: ZrO2, diameter: 0.1 mm) for a planetary ball mill were prepared. 10 parts by mass of the second media, 40 parts by mass of the third media, 0.75 parts by mass of solid electrolyte particles, and 6 parts by mass of butyl butyrate (solvent) were added to the second pot. Wet milling was carried out for 1 hour at a rotation speed of 200 rpm. After wet milling, the solvent was removed by drying.

[0053] No.2~No.6 As shown in the "Wet Milling" section of Figure 6, solid electrolyte particles were produced in the same manner as in No. 1, except that the rotation speed in the wet milling process was changed. Note that No. 3 was not subjected to the wet milling process. No. 3 is the base material (unprocessed product).

[0054] <Evaluation> Figure 1 shows the XRD spectra of samples No. 1 to No. 6. All samples have peaks at 2θ = 29.4 ± 0.5°, 41.4 ± 0.5°, and 47.3 ± 0.5°. The higher the rotation speed of the wet milling process, the higher the peak height ratio (I B / I A ), (I C / I A ) tends to become smaller. This is thought to be because the wet milling process reduces the crystallinity.

[0055] The Raman spectra of No. 1 and No. 3 to No. 5 are shown in Figure 2. In No. 1, the peak intensity was 388±3 cm -1 A shoulder peak was clearly observed in the Raman shift of . The shoulder peak is thought to be derived from impurity phases (Li2S, etc.). The impurity phases are thought to be generated by slight decomposition of the LGPS-type crystalline phase during wet milling.

[0056] Between each sample, the peak height ratio (I E / I D) is small. From this result, it is thought that the bulk crystallinity (the symmetry of the LGPS structure) is hardly changed by the wet milling process. It is thought that the crystallinity is locally reduced at the outermost surface of the particles during the wet milling process.

[0057] Figure 3 shows the cyclic voltammograms for No. 1 to No. 6. There is a tendency for the oxidation current peak to decrease as the rotation speed in the wet milling process increases (No. 1 to No. 6). It is thought that the wet milling process imparts oxidation resistance to the particle surface. However, when the rotation speed in the wet milling process exceeds 250 rpm, the oxidation current increases again (No. 6). This is thought to be due to the destruction of the particles. The destruction of the particles leads to the formation of fine particles. It is thought that the oxidation reaction is promoted by the increase in the amount of interface between the fine particles and VGCF (conductive material).

[0058] Figure 6 shows the ionic conductivities of No. 1 to No. 6. There is a tendency for the wet milling process to reduce the ionic conductivities. -3 High ionic conductivity on the order of S / cm is maintained.

[0059] From the above results, the peak height ratio (I B / I A ) is 0.20 to 0.35, and the peak height ratio (I C / I A ) is 0.30 to 0.45, improvement in oxidation resistance is expected.

[0060] <Additional Notes> In one aspect of the present disclosure, a method for producing solid electrolyte particles is provided. The method for producing solid electrolyte particles includes the following steps (a) and (b). (a) Solid electrolyte particles containing an LGPS-type crystalline phase are synthesized. (b) Surface treatment is applied to the solid electrolyte particles. The surface treatment converts the LGPS-type crystalline phase into an amorphous phase on at least a portion of the surface of the solid electrolyte particles.

[0061] The above (b) may include subjecting the solid electrolyte particles to a wet milling treatment. The wet milling treatment may be performed using a planetary ball mill. The rotation speed of the planetary ball mill may be, for example, 200 to 250 rpm. The treatment time may be, for example, 1 hour or more. [Explanation of symbols]

[0062] 10 solid electrolyte particle, 11 core part, 12 shell part.

Claims

1. containing Li, Ge, P and S, Formula (1) and Formula (2): 0.20≦I B / I A ≦0.35 …(1) 0.30≦I C / I A ≦0.45 …(2) Fulfilling the relationship, In the formula (1) and the formula (2), I A , I B and I C respectively indicate peak heights in an X-ray diffraction spectrum measured using CuKα radiation as an X-ray source, I A indicates the peak height at a diffraction angle of 29.4±0.5°, I B indicates a peak height at a diffraction angle of 41.4±0.5°, and I C indicates the peak height at a diffraction angle of 47.3±0.5°, Furthermore, formula (3): 1.20≦I E / I D …(3) Fulfilling the relationship, In the formula (3), I D and I E respectively represent peak heights in the Raman spectrum, I D denotes the peak height at a Raman shift of 420±10 cm −1 ; I E denotes the peak height at a Raman shift of 360±10 cm −1 , and The Raman spectrum has a shoulder peak at a Raman shift of 388±3 cm −1 . Solid electrolyte particles.

2. In the X-ray diffraction spectrum, The peak at a diffraction angle of 29.4±0.5° has a full width at half maximum of 0.15° or less. The solid electrolyte particles according to claim 1 .

3. It includes a core portion and a shell portion, the shell portion covers the periphery of the core portion, the core portion contains an LGPS-type crystalline phase, the shell portion includes an amorphous phase, The core portion is 10×10 -3 S / cm or more ionic conductivity, and The shell part is 1×10 -3 S / cm or less of ionic conductivity, The solid electrolyte particles according to claim 1 or 2.

4. The shell portion has a thickness of 100 nm or less. The solid electrolyte particles according to claim 3 .

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