Solid electrolyte, positive pole, electrolyte layer, and secondary battery

Abstract

To provide: a solid electrolyte which can be produced by low-temperature sintering and which has high ionic conductivity; and a secondary battery having the same.SOLUTION: A solid electrolyte includes a borated compound including: Li; an element R selected from the group consisting of Yb, Er, Ho, Tm, and La; an element A selected from the group consisting of Al, Fe, Mn, and Ga; and an element M selected from the group consisting of Zr and Ce.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a solid electrolyte, and a positive electrode, an electrolyte layer, and a secondary battery each including the electrolyte. [Background technology]

[0002] All-solid-state secondary batteries using solid electrolytes can improve heat resistance. In addition, the electrolyte does not leak or volatilize, so safety can be improved. Therefore, it is possible to reduce module costs and increase energy density.

[0003] As one of such solid electrolytes, a sulfide-based solid electrolyte has been reported. However, since the sulfide-based solid electrolyte uses sulfide as a raw material for its production, there is a problem in terms of workability. Therefore, as a solid electrolyte other than a sulfide-based solid electrolyte, an oxide-based solid electrolyte has been reported.

[0004] As a Li-based solid electrolyte, NASICON type Li1+xAlxTi 2-x (PO4)3(LATP), a perovskite-type Li 3+x La 2 / 3-x TiO3(LLT), garnet-type cubic Li7La3Zr2O 12 (LLZ) has been reported. In addition, β'' alumina type Na2O ·(5~7 )Al2O3, NASICON type Na3Zr2Si2PO 12 However, these solid electrolytes have problems such as limitations on the anode materials that can be used and the need for sintering at high temperatures exceeding 1000°C to improve electrical conductivity by tightly bonding the interfaces between solid electrolytes or between the solid electrolyte and the active material. In particular, sintering at high temperatures can form high-resistance phases at the interfaces between solid electrolytes or between the solid electrolyte and the active material, limiting the improvement of ionic conductivity.

[0005] For this reason, in recent years, attempts have been made to lower the sintering temperature. 2+xC 1-x B x It has been disclosed that by using a solid electrolyte containing lithium borate, such as O3, it is possible to reduce the firing temperature to around 900°C.

[0006] Moreover, Patent Document 2 states that the sintering temperature for forming a solid electrolyte can be reduced to 650 to 800° C. by mixing Li3BO3 with an LLZ-based oxide. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 5-54712 [Patent Document 2] JP 2013-37992 A Summary of the Invention [Problem to be solved by the invention]

[0008] The firing temperature of the secondary batteries containing the solid electrolytes disclosed in Patent Documents 1 and 2 has been lowered, making it difficult for a high-resistance phase to form as an intermediate layer between the solid electrolyte and other materials. However, the ionic conductivity σ SE At room temperature, 1 × 10 -7 Therefore, there is a need for oxide-based solid electrolytes with improved ionic conductivity.

[0009] An object of the present invention is to provide a solid electrolyte that can be produced by sintering at a low temperature and has high ion conductivity, as well as a positive electrode, an active material layer, and a secondary battery that each contain such a solid electrolyte. [Means for solving the problem]

[0010] The solid electrolyte according to the embodiment of the present invention has the general formula Li 6-x R 1-y-a A y-b M x Includes oxides represented by the formula (BO3)3.

[0011] However, R is at least one or two elements selected from the group including trivalent elements Yb, Er, Ho, and Tm, A is an element selected from Al, Fe, Mn, and Ga, M1 is a tetravalent element, x and y are real numbers satisfying 0 < x, y < 1, and a and b are real numbers satisfying a + b = x. The solid electrolyte according to an embodiment of the present invention contains a borate containing Li, an element R selected from the group including Yb, Er, Ho, Tm, and La, an element A selected from the group including Al, Fe, Mn, and Ga, and an element M selected from the group including Zr and Ce.

[0012] Also, the solid electrolyte according to an embodiment of the present invention contains a borate containing Li, an element R selected from the group including Yb, Er, Ho, Tm, and La, an element A selected from the group including Al, Fe, Mn, and Ga, and an element M selected from the group including Zr and Ce. In the X-ray diffraction analysis using CuKα rays, it exhibits two diffraction peaks in the range where the diffraction angle 2θ is 28.0 degrees or more and 29.0 degrees or less, and the difference in diffraction angle 2θd between the diffraction peak on the high-angle side and the diffraction peak on the low-angle side is 0.416 degrees or more.

[0013] Furthermore, the solid electrolyte according to an embodiment of the present invention has the general formula Li 6-x R 1-y-a A y-b M x (BO3)3. However, in the formula, R includes rare earth elements selected from the group including Yb, Er, Ho, Tm, and La and is at least one or two elements, A is a metal element selected from Al, Fe, Mn, and Ga, M is a tetravalent element, x and y are real numbers satisfying 0 < x, y < 1, and a and b are real numbers satisfying a + b = x. The general formula Li 6-x R 1-y-a A y-b M xIt is a solid electrolyte containing an oxide represented by (BO3)3. However, in the formula, R is a rare earth element selected from the group including Yb, Er, Ho, Tm, and La, A is a metal element selected from Al, Fe, Mn, and Ga, M is an element selected from the group including Zr and Ce, x and y are real numbers satisfying 0 < x, y < 1, and a and b are real numbers satisfying a + b = x.

Advantages of the Invention

[0014] According to the present invention, it is possible to obtain a solid electrolyte that can be produced by sintering at a low temperature and has high ionic conductivity, and a secondary battery having the same.

Brief Description of the Drawings

[0015] [Figure 1] It is a diagram showing the relationship between the ionic conductivity of the solid electrolyte according to Examples 1 to 17 included in the first embodiment and the value of the composition x (x1 + x2) of the substitution element M. [Diagram 2] It is a diagram showing the relationship between the ionic conductivity of the solid electrolyte according to Examples 1 to 17 included in the first embodiment and the value of the composition y of the substitution element A. [Diagram 3] It shows the diffraction curves of the solid electrolytes according to Examples 1 to 14. [Figure 4] It shows the diffraction curves of the solid electrolytes according to Examples 15 to 17. [Diagram 5] It shows the diffraction curves of the solid electrolytes according to Examples 1 to 8. [Figure 6] It shows the diffraction curves of the solid electrolytes according to Examples 12 to 14. [Figure 7] It shows the diffraction curves of the solid electrolytes according to Examples 15 to 17. [Figure 8] It is a schematic cross-sectional view (a) of a secondary battery according to the second embodiment and a partially enlarged view (b) of the positive electrode and the electrolyte layer.

Modes for Carrying Out the Invention

[0016] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0017] (First Embodiment) General formula Li 6-x R 1-y-a A y-b M x It is a solid electrolyte containing an oxide represented by (BO3)3.

[0018] In the formula, R is an element selected from the group consisting of Yb, Tm, Ho, Er, and La, A is an element selected from the group consisting of Al, Fe, Mn, and Ga, and M is a tetravalent element selected from the group containing Zr and Ce. Further, a and b satisfy 0 ≦ a, b < 1 and a + b = x, and x and y are real numbers satisfying 0 < x, y < 1.

[0019] Also, when R in the formula contains at least two elements selected from the group containing the trivalent elements Yb, Er, Ho, Tm, and La, it may be combined with other trivalent elements having an ionic radius close to that of the elements selected from the group containing Yb, Er, Ho, Tm, and La.

[0020] The solid electrolyte according to this embodiment is equivalently described as containing an oxide represented by the general formula Li 6-x R 1-y-a A y-b M x (BO3)3.

[0021] In the formula, R is at least one or two rare earth elements selected from the group consisting of Yb, Er, Ho, Tm, and La, A is an element selected from the group consisting of Al, Fe, Mn, and Ga, and M is an element selected from the group containing Zr and Ce. Further, a and b satisfy 0 ≦ a, b < 1 and a + b = x, and x and y are real numbers satisfying 0 < x, y < 1.

[0022] Also, when R in the formula contains at least two elements selected from the group containing the rare earth elements Yb, Er, Ho, Tm, and La, not only combinations of the rare earth elements in such a group but also combinations of these elements with other rare earth elements having an ionic radius close to them may be used.

[0023] The reason why the ionic conductivity is improved in the solid electrolyte containing the oxide represented by the above general formula is presumed to be as follows.

[0024] When some of the rare earth elements R, Yb, Er, Ho, Tm, and La, are replaced with the element M, which has a tetravalent valence, the charge balance is adjusted so that the crystal as a whole becomes neutral, and the Li in the crystal lattice is + The part where the element is missing is generally called a vacancy. The Li around the vacancy + The ionic conductivity is improved by the concerted action of the phenomenon in which ions move to vacancies, a phenomenon commonly referred to as hopping. In this case, it is believed that the crystal lattice changes when some of the rare earth elements Yb, Er, Ho, Tm, and La are replaced by the metal element A, Al, Fe, Mn, and Ga, which have the same trivalent valence. In this case, Li + The vacancies that serve as the pathways for ions are Li + It is believed that the size of the object will be suitable for movement.

[0025] In general, an atomic radius within ±15% is considered to be suitable for element substitution, but the atomic radii of the rare earth element R and the metal element A mentioned above are outside this range, and it is considered difficult to substitute them. However, although it has not been possible to verify what stabilization mechanism is involved, as shown in the comparison results of XRD in Figures 3 and 4, the crystal structure remains unchanged before and after the substitution, and no impurities are detected, so in this compound, the rare earth element R is substituted with the metal element A. Since the substitution is carried out with an element with a significantly different atomic radius, changes also occur in the crystal lattice, resulting in the above-mentioned Li + It is assumed that this will effectively form a passage for the

[0026] The solid electrolyte of the present embodiment is, in other words, a solid electrolyte containing a borate including Li, an element R selected from the group including Yb, Er, Ho, Tm, and La, an element A selected from the group including Al, Fe, Mn, and Ga, and an element M selected from the group including Zr and Ce.

[0027] The solid electrolyte of the present embodiment preferably has a monoclinic crystal structure.

[0028] In X-ray diffraction analysis (hereinafter, referred to as XRD) using CuKα radiation, a diffraction peak occurring at a diffraction angle 2θ of approximately 28 degrees varies depending on the composition of the solid electrolyte.

[0029] The general formula Li 6-x R 1-y-a A y-b M x In the solid electrolyte of the oxide represented by (BO3)3, where R is Yb and A is Al, it is preferable that the diffraction peak is in the range of 2θ=28.0 degrees or more and 28.20 degrees or less in XRD using CuKα radiation, and more preferably in the range of 2θ=28.10 degrees or more and 28.20 degrees or less.

[0030] In XRD using CuKα radiation, the position of the diffraction peak occurring near 2θ=28 degrees can be controlled by adjusting the value of x in the above general formula and by changing the element represented by M.

[0031] In the above general formula, M is a tetravalent element and at least one element selected from the group including Zr and Ce.

[0032] The trivalent elements Yb, Er, Ho, Tm, and La in R can be easily substituted with elements that have a similar ionic radius. Specifically, Zr 4+ , Ce 4+ , Sn 4+ , Ti 4+ , Nb 4+ , Pb 4+ ,Pr 4+ , Nb 5+ Among them, Zr 4+ , Ce 4+ is more easily replaced.

[0033] In the above general formula, a and b are real numbers satisfying 0 ≦ a, b < 1 and a + b = x, and x and y are real numbers satisfying 0 < x, y < 1. a and b respectively correspond to the ratios of replacing element R and element A with replacing element M. The ratio of replacing element R and element A with replacing element M may be arbitrary, but it is preferable that the ratio of replacing element M be the same as the ratio of element R and element A. That is, it is preferable that a:b = [R]:[A]. As x corresponding to the substitution amount of element R by replacing element M, those of 0.025 or more and 0.4 or less are adopted. Further, as more preferable x, those of 0.050 or more and 0.227 or less are adopted. a and b respectively represent the ratios at which the above elements R and A are replaced with replacing element M. As y corresponding to the substitution amount of element R by element A, those of 0.05 or more and 0.50 or less are adopted. Further, as more preferable x, those of 0.010 or more and 0.200 or less are adopted.

[0034] The reason why the above range of x is preferable is presumed as follows. When the value of x is less than 0.025, since the substitution amount of element R is small, sufficient structural defects cannot be formed, and the path through which Li + ions pass is not sufficiently formed, so that the resulting ionic conductivity is not improved. Also, when the value of x is greater than 0.4, since the amount of replacing element M becomes too large, excessive element M that does not contribute to the substitution with element R in the crystal contributes as an inhibitory component of ionic conduction rather than the substitution effect in the crystal.

[0035] The reason why the above range of y is preferable is presumed as follows. When the value of y is less than 0.050, since the substitution amount of element R is small, sufficient structural changes do not occur, and the path through which ions pass does not change to a suitable size, so that the resulting ionic conductivity is not improved. Also, when the value of y is greater than 0.50, since the amount of replacing element A becomes too large, excessive element A that does not contribute to the substitution with element R in the crystal contributes as an inhibitory component of ionic conduction rather than the substitution effect in the crystal.

[0036] Next, the manufacturing method of the solid electrolyte of the present embodiment will be described.

[0037] The manufacturing method of the solid electrolyte of the present embodiment is the general formula Li6-x R 1-y-a A y-b M x The method includes a firing step of heating elements constituting a solid electrolyte containing an oxide represented by the formula (BO3)3, such as Li, R, A, M, or oxides thereof, in an oxygen-containing atmosphere. (In the formula, R is at least one or two elements selected from the group including rare earth elements Yb, Er, Ho, Tm, and La, A is an element selected from the group including Al, Fe, Mn, and Ga, and M is a tetravalent element.) The method for producing a solid electrolyte of the present embodiment can include a pre-firing step of synthesizing an oxide represented by the above general formula in a solid phase by heat treatment at a temperature below the melting point of the oxide, and a step of densifying the obtained oxide by heat treatment.

[0038] Hereinafter, the method for producing the solid electrolyte of this embodiment, which includes the above-mentioned pre-firing step and the above-mentioned main firing step, will be described in detail, but the method is not limited to the following production method.

[0039] <Pre-firing process> In the pre-sintering process, Li 6-x R 1-y-a A y-b M x To obtain (BO3)3, chemical reagent grade raw materials such as Li3BO3, H3BO3, Yb2O3, Er2O3, Ho2O3, Tm2O3, La2O3, α-Al2O3, Fe2O3, Mn2O3, Ga2O3, ZrO2, and CeO2 are weighed and mixed using a specified stoichiometric ratio as an index. Other raw materials that are weighed to obtain the specified stoichiometric ratio include SnO2 and Nb2O3. Here, R is at least one or two elements selected from the group including rare earth elements Yb, Er, Ho, Tm, and La, A is an element selected from the group including Al, Fe, Mn, and Ga, and M is a tetravalent element.

[0040] The equipment used for mixing may be a mortar and pestle, or a mixer such as a ball mill.

[0041] After the mixed powder of the above-mentioned raw materials is obtained by the mixing process, the mixed powder is pressurized and molded into pellets. Here, the pressurization method may be a known pressurization method such as cold uniaxial molding or cold isostatic pressing. The conditions for pressurization in the calcination step are not particularly limited, but may be, for example, a pressure of 100 to 300 MPa.

[0042] The obtained pellets are calcined at 500° C. to 800° C. using an air calciner or the like to perform solid phase synthesis. The time for the calcination step is not particularly limited, but can be, for example, about 700 to 750 minutes (eg, 720 minutes).

[0043] The obtained calcined body is represented by the general formula Li 6-x R 1-x M x It is an oxide represented by the formula (BO3)3. The pre-sintered body can be pulverized using a mortar and pestle to obtain a pre-fired powder.

[0044] <Main firing process> In the main firing step, the pre-fired body obtained in the pre-firing step and at least one selected from the group including the pre-fired body are pressure-molded and main fired to obtain a dense sintered body.

[0045] The pressure molding and the main sintering may be performed simultaneously using spark plasma sintering or hot pressing, or pellets may be produced by cold uniaxial molding and then the main sintering may be performed in an air atmosphere, etc. The conditions for the pressure molding in the main sintering are not particularly limited, but may be, for example, a pressure of 100 to 300 MPa.

[0046] The temperature during the main firing is preferably 800° C. or lower, more preferably 700° C. or lower, and further preferably 680° C. or lower.

[0047] The time for the main firing step can be appropriately changed depending on the main firing temperature and the like, but can be, for example, about 700 to 750 minutes (eg, 720 minutes).

[0048] The cooling method in the main firing step is not particularly limited, and the material may be naturally cooled, or may be cooled more gradually than naturally cooled.

[0049] Next, the secondary battery of this embodiment will be described.

[0050] A secondary battery generally has a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, an electrolyte containing a solid electrolyte disposed between the positive electrode and the negative electrode, and a current collector as necessary.

[0051] The secondary battery of the present embodiment is a secondary battery having at least a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and an electrolyte, and at least one selected from the group containing the positive electrode, the negative electrode, and the electrolyte contains the solid electrolyte of the present embodiment.

[0052] In the secondary battery of this embodiment, the electrolyte may be the solid electrolyte of this embodiment, or may contain other solid electrolytes. The other solid electrolytes are not particularly limited, and examples thereof include Li3PO4, Li7La3Zr2O 12 , Li 0.33 La 0.55 TiO3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3, Li 1.3 Al 0.3 Ti 1.7 (PO4)3, etc. The content of the solid electrolyte of the present embodiment in the electrolyte of the secondary battery of the present embodiment is preferably 25% by mass or more, more preferably 50% by mass or more, further preferably 75% by mass or more, and particularly preferably 100% by mass.

[0053] The secondary battery of this embodiment can be obtained by a known method, such as stacking a positive electrode, a solid electrolyte, and a negative electrode, molding, and heat treatment. The solid electrolyte of this embodiment can be produced by a heat treatment at a lower temperature than in the prior art, and therefore the formation of a high resistance phase caused by the reaction between the solid electrolyte and the electrode active material can be reduced, thereby obtaining a secondary battery with excellent output characteristics. Note that the term "solid" in this specification includes those that have the self-supporting property to the extent that they maintain a certain shape and volume even if the orientation of the object is changed, and a viscosity of 1×10 7 Less than cP (1 × 10 4 This means that the material has a non-liquidity of less than Pa·sec.

[0054] Next, methods for measuring physical properties according to the present disclosure will be described.

[0055] Identification of R, A, M If the collected sample is not a mixture with other materials, the composition ratio of the sample can be identified by dissolving the collected sample in solution and then using inductively coupled plasma atomic emission spectrometry (ICP-AES), wavelength dispersive X-ray fluorescence spectrometry (WDXRF), etc. WDXRF is sometimes referred to as WDX.

[0056] On the other hand, if the collected sample is highly likely to be a mixture, scanning analysis devices capable of obtaining elemental mapping images, such as X-ray photoelectron spectroscopy (XPS, ESCA) and scanning electron microscopes equipped with energy dispersive X-ray fluorescence (EDXRF) analysis devices, can be applied. Hereinafter, scanning electron microscopes equipped with energy dispersive X-ray fluorescence (EDXRF) analysis devices may be abbreviated as SEM / EDX. Also, if the collected sample is highly likely to be a mixture, the crystal structure may be identified using a transmission electron microscope (TEM-ED) equipped with electron beam diffraction capabilities. Note that EDXRF may be referred to as EDX instead.

[0057] In order to precisely obtain the composition ratio between the light element Li and other elements with higher atomic numbers such as B, O, Al, Zr, and rare earth elements, ICP-AES and XPS are used.

[0058] In addition, when the collected sample is a mixture, pretreatment is used to selectively remove non-target areas of the analysis by physical removal such as dicing or ion beam processing, chemical removal such as dry etching or wet etching, or a combination of these. Pretreatment may involve washing, degreasing, sectioning, crushing, pelleting, etc.

[0059] For standard samples, SEM / EDX can be used with the S-4800 manufactured by Hitachi High-Technologies Corporation as the analytical device.

[0060] -X-ray diffraction peak measurement For the X-ray diffraction analysis of the solid electrolyte, RINT-2100 manufactured by Rigaku Corporation is used.

[0061] The powder obtained by crushing the solid electrolyte with a mortar and pestle is subjected to X-ray diffraction analysis using characteristic X-rays of CuKα. The temperature is room temperature, the analysis range is 10°C to 70°C, the step is 0.016°C, and the scan speed is 0.5 steps / sec.

[0062] Second Embodiment <Secondary battery, positive electrode structure> An electrolyte layer 40 having a solid electrolyte 44 according to the first embodiment and a secondary battery 100 including the electrolyte layer 40 will be described with reference to FIGS. 8(a) and 8(b).

[0063] FIG. 8(a) is a schematic cross-sectional view of a secondary battery 100 including an electrolyte layer 40 to which the solid electrolyte 44 of this embodiment is applied. The secondary battery 100 includes an electrolyte layer 40 on the side opposite to the side of the positive electrode collector layer 10 in contact with the positive electrode active material layer 20. The secondary battery 100 includes an anode 70 on the side opposite to the side where the electrolyte layer 40 is in contact with the positive electrode active material layer 20. The anode 70 includes an anode active material layer 50 on the side opposite to the side where the electrolyte layer 40 is in contact with the positive electrode active material layer 20. The anode 70 includes an anode current collector layer 60 on the side opposite to the side where the negative electrode active material layer 50 is in contact with the electrolyte layer 40. In other words, the secondary battery 100 includes an anode 70, an electrolyte layer 40, and a cathode 30 in the stacking direction 200.

[0064] As shown in FIG. 8(b), the electrolyte layer 40 to which the electrolyte 44 of this embodiment is applied is in contact with a positive electrode 30 having a positive electrode collector layer 10 and a positive electrode active material layer 20 including active material particles 22 and a positive electrode electrolyte 24. In the present specification, a structure in which lithium ions (active material ions) are exchanged between the electrolyte layer 40 and the positive electrode is referred to as a positive electrode, and therefore the positive electrode active material layer 20 obtained by removing the positive electrode collector layer 10 from the positive electrode 30 in FIG. 8(a) may be referred to as a positive electrode 20. In addition, since the positive electrode active material layer 20 of this embodiment includes the positive electrode electrolyte 24, it may be referred to as a composite positive electrode active material layer 20 or a composite positive electrode structure 20.

[0065] The current collector layer 10 is a conductor that conducts electrons between an external circuit (not shown) and the active material layer. The current collector layer 10 may be in the form of a free-standing film of a metal such as SUS or aluminum, a metal foil, or a laminated form with a resin base.

[0066] The positive electrode active material layer 20 includes positive electrode active material layers 20a, 20b, and 20c as sublayers. The positive electrode active material layers 20a, 20b, and 20c are classified by the units of lamination in the layer thickness direction 200 before the active material particles 22 and the positive electrode electrolyte 24 are sintered. The positive electrode active material layers 20a, 20b, and 20c may have a distribution in the layer thickness direction in the volume fraction of the active material particles 22 and the positive electrode electrolyte 24, the conductive additive (not shown), the porosity, and the like. The layer thickness direction 200 is parallel or antiparallel to the lamination direction in which the layers are laminated, and may be referred to as the lamination direction 200.

[0067] The solid electrolyte 44 according to this embodiment is applied to the positive electrode electrolyte 24 contained in the composite positive electrode active material layer 20. The positive electrode electrolyte 24 and the solid electrolyte 44 contained in the electrolyte layer 40 may have a common composition, particle size distribution, and other characteristics, or may have different compositions, particle size distributions, and other characteristics.

[0068] (Negative electrode) Known methods can be applied to the method for manufacturing the negative electrode. As in the second embodiment of the present application, the method for manufacturing the positive electrode 30 of the first embodiment may be applied mutatis mutandis to the creation of the negative electrode. The negative electrode may be in a form in which the negative electrode active material and the solid electrolyte are mixed in the layer, similar to the positive electrode 30, or a metal such as metallic Li or In-Li may be formed as a film.

[0069] [Negative electrode active material] Examples of the negative electrode active material include metals, metal fibers, carbon materials, oxides, nitrides, silicon, silicon compounds, tin, tin compounds, and various alloy materials. Among them, from the viewpoint of capacity density, metals, oxides, carbon materials, silicon, silicon compounds, tin, tin compounds, etc. are preferable. Examples of the metal include metallic Li and In-Li, and examples of the oxide include Li4Ti5O 12 (LTO: lithium titanate), etc. Examples of the carbon material include various natural graphites (graphite), coke, carbon in the process of graphitization, carbon fibers, spherical carbon, various artificial graphites, amorphous carbon, etc. Examples of the silicon compound include silicon-containing alloys, silicon-containing inorganic compounds, silicon-containing organic compounds, solid solutions, etc. Examples of the tin compound include SnO b (0 < b < 2), SnO2, SnSiO3, Ni2Sn4, Mg2Sn, etc. In addition, the above negative electrode material may contain a conductive assistant. Examples of the conductive assistant include graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black. The conductive assistant includes conductive fibers such as carbon fibers, carbon nanotubes, and metal fibers, metal powders such as carbon fluoride and aluminum, conductive whiskers such as zinc oxide, conductive metal oxides such as titanium oxide, and organic conductive materials such as phenylene dielectrics.

Example

[0070] An example in which the solid electrolyte of this embodiment is manufactured and evaluated as a sintered body will be described. Note that the present disclosure is not limited to the following examples.

[0071] [Example 1] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Yb2O3 (Kojundo Chemical Laboratory), α-Al2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.95 Yb 0.85 Al 0.045 Zr 0.1 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0072] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0073] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0074] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Example 1. The heating temperature was 670° C., and the holding time was 720 minutes.

[0075] [Examples 2 to 8] <Pre-firing process> A calcined body and a calcined powder were prepared in the same manner as in Example 1, except that each raw material described in Example 1 was weighed in a predetermined stoichiometric ratio so that each value was the value described in Table 1.

[0076] <Main firing process> The pre-sintered powder obtained above was subjected to the same main sintering process as in Example 1 to produce a sintered body.

[0077] [Examples 9 and 10] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Yb2O3 (Kojundo Chemical Laboratory), α-Al2O3 (Kojundo Chemical Laboratory), ZrO2 (Nippon Denko), and CeO2 (Iwatani Corporation) were prepared as raw materials for the solid electrolyte. 5.875 Yb 0.7875 Al 0.0875 Zr 0.1 Ce 0.025 (BO3) 3, Li 5.877 Yb 0.7591 Al 0.135 Zr 0.104 Ce 0.0186 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0078] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0079] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0080] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Example 1. The heating temperature was 670° C., and the holding time was 720 minutes.

[0081] [Example 11] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Yb2O3 (Kojundo Chemical Laboratory), La2O3 (Kojundo Chemical Laboratory), α-Al2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.875 Yb 0.7200 La 0.090 Al 0.090 Zr 0.1 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0082] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0083] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0084] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Example 26. The heating temperature was 670° C., and the holding time was 720 minutes.

[0085] [Example 12] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Yb2O3 (Kojundo Chemical Laboratory), α-Fe2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.9 Yb 0.81 Fe 0.09 Zr 0.1 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0086] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0087] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0088] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Example 1. The heating temperature was 670° C., and the holding time was 720 minutes.

[0089] [Example 13] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Yb2O3 (Kojundo Chemical Laboratory), Mn2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.9 Yb 0.81 Mn 0.09 Zr 0.1 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0090] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0091] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0092] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Example 1. The heating temperature was 670° C., and the holding time was 720 minutes.

[0093] [Example 14] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Yb2O3 (Kojundo Chemical Laboratory), Ga2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.9 Yb 0.81 Ga 0.09 Zr 0.1 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0094] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0095] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0096] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Example 1. The heating temperature was 670° C., and the holding time was 720 minutes.

[0097] [Example 15] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Tm2O3 (Kojundo Chemical Laboratory), α-Al2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.9 Tm 0.810 Al 0.090 Zr 0.100 A calcined body and a calcined powder were produced in the same manner as in Example 1, except that the components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3.

[0098] <Main firing process> The pre-sintered powder obtained above was subjected to the same main sintering process as in Example 1 to produce a sintered body. The heating temperature was 670° C., and the holding time was 720 minutes.

[0099] [Example 16] Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Ho2O3 (Kojundo Chemical Laboratory), α-Al2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.9 Ho 0.810 Al 0.090 Zr 0.100 A calcined body and a calcined powder were produced in the same manner as in Example 1, except that the components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3.

[0100] <Main firing process> The pre-sintered powder obtained above was subjected to the same main sintering process as in Example 1 to produce a sintered body. The heating temperature was 670° C., and the holding time was 720 minutes.

[0101] [Example 17] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Er2O3 (Kojundo Chemical Laboratory), α-Al2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.9 Er 0.810 Al 0.090 Zr 0.100 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0102] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0103] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0104] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Example 7. The heating temperature was 670° C., and the holding time was 720 minutes.

[0105] [Comparative Example 1] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Y2O3 (Kojundo Chemical Laboratory), α-Al2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.9 Y 0.810 Al 0.090 Zr 0.100 A calcined body and a calcined powder were produced in the same manner as in Example 1, except that the components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3.

[0106] <Main firing process> The pre-sintered powder obtained above was subjected to the same main sintering process as in Example 1 to produce a sintered body. The heating temperature was 670° C., and the holding time was 720 minutes.

[0107] [Comparative Example 2] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Sm2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.9 Sm 0.810 Al 0.090 Zr 0.100 A calcined body and a calcined powder were produced in the same manner as in Example 1, except that the components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3.

[0108] <Main firing process> The pre-sintered powder obtained above was subjected to the same main sintering process as in Example 1 to produce a sintered body. The heating temperature was 670° C., and the holding time was 720 minutes.

[0109] [Reference example 1] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Yb2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.900 Yb 0.900 Zr 0.100 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0110] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0111] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0112] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Reference Example 1. The heating temperature was 650° C., and the holding time was 720 minutes.

[0113] [Reference example 2] <Pre-firing process> Li3BO3 (Toshima Manufacturing), H3BO3 (Kishida Chemical), Y2O3 (Kojundo Chemical Laboratory), and ZrO2 (Nippon Denko) were prepared as raw materials for the solid electrolyte. 5.900 Y 0.900 Zr 0.100 The components were weighed out in a predetermined stoichiometric ratio to obtain (BO3)3, and mixed in a mortar and pestle.

[0114] The mixed powder was then cold uniaxially molded using a hydraulic press SSP-10A manufactured by Shimadzu Corporation, and heat-treated in an air atmosphere at a heating temperature of 650°C and a holding time of 720 minutes.

[0115] The obtained calcined body was pulverized in a mortar and pestle to produce a calcined powder.

[0116] <Main firing process> The calcined powder obtained above was molded and heat-treated in the same manner as in the calcination to produce a sintered body of Reference Example 2. The heating temperature was 650° C., and the holding time was 720 minutes.

[0117] The sintered bodies of Examples 1 to 17, Comparative Examples 1 to 2, and Reference Examples 1 to 2 were subjected to composition analysis and X-ray diffraction peak measurement by the above-mentioned methods. In addition, ion conductivity was measured by the following method. The method for measuring ion conductivity is described below. The obtained evaluation results are shown in Table 1.

[0118] -Ionic conductivity measurement Gold electrodes were formed on the top and bottom surfaces of the flat sintered body obtained by this firing using a magnetron sputtering device MSP-10 manufactured by Vacuum Device Co., Ltd., to prepare a sample for measuring AC impedance.

[0119] The AC impedance was measured using a potentio / galvanostat SI1287A and a frequency response analyzer 1255B manufactured by Solartron Analytical Co., Ltd. The measurement conditions were room temperature and a frequency of 1 MHz to 0.1 Hz.

[0120] The resistance of the sintered body was calculated from a complex impedance plot obtained by impedance measurement. The ionic conductivity was calculated from the calculated resistance, the thickness of the sintered body, and the electrode area using the following formula.

[0121] Ionic conductivity (S / cm) = thickness of sintered body (cm) / (resistance of sintered body (Ω) × electrode area (cm 2 )) ·result Table 1 shows the stoichiometric amounts of raw materials, heating temperatures during main firing, diffraction peak positions, and ionic conductivity when producing the solid electrolytes according to Examples 1 to 17 and Comparative Examples 1 to 2. Fig. 1 also shows the relationship between the ionic conductivity of the solid electrolytes according to Examples 1 to 17, Comparative Examples 1 to 2, and Reference Examples 1 to 3 included in the first embodiment and the value of the composition x (x1+x2) of the substituting element M. Fig. 2 also shows the relationship between the ionic conductivity of the solid electrolytes according to Examples 1 to 17 and Comparative Examples 1 to 2 included in the first embodiment and the value of the composition y of the metal element A.

[0122] As a result of the composition analysis, it was confirmed that all the sintered bodies (solid electrolytes) contained the raw material elements listed in Table 1. Furthermore, the sintered bodies (solid electrolytes) according to Examples 1 to 17 could be densified at a low temperature of less than 700° C., and were solid electrolytes exhibiting high ionic conductivity.

[0123] Diffraction curves obtained by XRD in the range of 2θ=10 degrees to 40 degrees are shown in Figures 3 and 4. It can be seen that Examples 1 to 14 have a crystal structure of Li6Yb(BO3)3, Example 15 has a crystal structure of Li6Er(BO3)3, Example 16 has a crystal structure of Li6Ho(BO3)3, and Example 17 has a crystal structure of Li6Tm(BO3)3, all of which are monoclinic crystal structures.

[0124] 5 and 6 show the diffraction curves in the range of 2θ=27 degrees or more and 29 degrees or less obtained by XRD when R is Yb. It can be seen that the peak positions around the diffraction angles 2θ=28.1 degrees and 28.5 degrees observed in the solid electrolytes according to Examples 1 to 8 are shifted to the higher angle side than the peak position of the solid electrolyte according to Reference Example 1. On the other hand, when comparing the X-ray diffraction profiles of the solid electrolytes according to Examples 1 to 8 with Reference Example 2, it can be seen that the peak positions around the diffraction angles 2θ=28.1 degrees and 28.5 degrees are almost the same. From these, it is considered that the X-ray diffraction profile has changed in response to the change in the crystal structure caused by at least one element selected from the group including M substituting at least a part of the rare earth element Yb and the metal element A.

[0125] FIG. 7 shows X-ray diffraction curves of the solid electrolytes according to Examples 15 to 17 in the range of diffraction angle 2θ=27 degrees or more and 29 degrees or less. It can be seen that the peak positions of the solid electrolyte according to Example 15 near the diffraction angles 2θ=28.1 degrees and 28.5 degrees are shifted to the higher angle side than the peak positions of the solid electrolyte according to Reference Example 2. Furthermore, the peak positions of the solid electrolyte according to Example 15 near the diffraction angles 2θ=28.1 degrees and 28.5 degrees are almost the same as those of the solid electrolyte according to Reference Example 5. From these facts, it is considered that the change in the X-ray diffraction profile corresponds to the change in the crystal structure caused by at least one element selected from the group including M substituting at least a part of Er, which is a rare earth element.

[0126] The solid electrolytes of Examples 16 and 17 also exhibit a peak shift to the high angle side similar to that of Example 15. It is considered that the solid electrolytes of Examples 16 and 17 exhibit a change in the X-ray diffraction profile corresponding to a change in the crystal structure caused by at least one element selected from the group including M substituting at least a part of the rare earth elements Ho and Tm and the metal element A.

[0127] In addition, the ionic conductivity σ is 5×10 -7As shown in Table 1, the solid electrolytes according to Examples 1 to 17 exhibiting a β-S / cm or more show a peak shift of the bimodal diffraction angle peak to the wide angle side with a high-angle shift of the X-ray diffraction angle peak. That is, it can be seen that the difference in diffraction angle 2θd between the high-angle diffraction peak observed at 28.3 to 29.0 degrees and the low-angle diffraction peak observed at 28.0 to 28.3 degrees is 0.416 degrees or more in the range of 28.0 degrees to 29.0 degrees. That is, the solid electrolyte according to this embodiment contains a borate containing Li, an element R selected from the group including Yb, Er, Ho, Tm, and La, an element A selected from the group including Al, Fe, Mn, and Ga, and an element M selected from the group including Zr and Ce. Furthermore, the solid electrolyte according to this embodiment is, in other words, an electrolyte that exhibits two diffraction peaks in a diffraction angle 2θ range of 28.0 degrees or more and 29.0 degrees or less in XRD using CuKα radiation, and the diffraction angle difference 2θd between the high-angle and low-angle diffraction peaks is 0.43 degrees or more.

[0128] In addition, the two diffraction angle peaks observed in the range of diffraction angle 2θ of 27.4 degrees to 29.0 degrees may further exhibit multiple peaks including three peaks and four peaks depending on the crystallinity. In this specification, the diffraction angle 2θ of 28.3 degrees is represented as having one peak each on the low angle side and the high angle side. In this way, the diffraction angle peaks are separated by fitting to a bimodal diffraction angle profile.

[0129] The high-angle diffraction peak is broadened and shifted to the high-angle side more significantly than the low-angle diffraction peak with an increase in the component of the substituting element M or an increase in ionic conductivity. From this, it can be interpreted that the crystal structure of the solid electrolyte 44 of this embodiment is changed compared to the unsubstituted comparative example, so that a plurality of crystal structures having distributions in lattice spacing and crystallite size are mixed.

[0130] In addition, the solid electrolytes according to Examples 1 to 17, which exhibited an ionic conductivity of 5E-7 (S / cm) or more, had an atomic concentration ratio [M] / [R]+[A] of the concentration of the substituting element M to the total concentration of the rare earth element R and the metal element A of 0.05 or more and 0.43 or less. Furthermore, the solid electrolytes according to Examples 1 to 15, which exhibited an ionic conductivity of 2E-5 (S / cm) or more, had an atomic concentration ratio [M] / [R]+[A] of the substituting element M to the rare earth element R and the metal element A of 0.11 or more and 0.25 or less.

[0131] In the solid electrolytes according to Examples 1 to 17 exhibiting an ionic conductivity of 5E-7 (S / cm) or more, the atomic concentration ratio [A] / [R] of the substituting metal element A to the rare earth element R was 0.05 or more and 1.00 or less. Furthermore, in the solid electrolytes according to Examples 1 to 17 exhibiting an ionic conductivity of 2E-5 (S / cm) or more, the atomic concentration ratio [A] / [R] of the substituting metal element A to the rare earth element R was 0.11 or more and 0.25 or less. [Table 1] [Explanation of symbols]

[0132] 44 Solid electrolyte

Claims

1. A solid electrolyte containing an oxide represented by the general formula Li ６－ｘ R １－ｙ－ａ A ｙ－ｂ M ｘ (BO ３ ) ３ where a, b satisfy 0 ≦ a, b < 1 and a + b = x, and x, y are real numbers satisfying 0 < x, y < 1. However, in the formula, R is an element selected from Yb, Tm, Ho, Er, La, A is an element selected from Al, Fe, Mn, Ga, M is a tetravalent element selected from the group containing Zr, Ce,

2. The solid electrolyte according to claim 1, which exhibits a diffraction peak in the range of 2θ = 28.0 degrees or more and 29.0 degrees or less in X-ray diffraction analysis using CuKα rays, and the difference 2θd in the diffraction angle between the diffraction peak on the high-angle side and the diffraction peak on the low-angle side is 0.416 degrees or more.

3. The solid electrolyte according to claim 1, wherein R is Yb, A is Al, and exhibits a diffraction peak in the range of 2θ = 28.10 degrees or more and 28.20 degrees or less in X-ray diffraction analysis using CuKα rays.

4. The solid electrolyte according to claim 1, wherein R is Yb, A is Al, M is Zr, and x satisfies 0 < x < 1.

5. A positive electrode according to claim 1, having a surface on which a lithium ion transfer occurs between the solid electrolyte and the electrolyte, and the solid electrolyte and the active material are arranged.

6. A secondary battery comprising the positive electrode according to claim 5, an electrolyte layer disposed so as to be in contact with the surface and performing lithium ion transfer with the positive electrode, and a negative electrode in contact with the opposite surface of the surface of the electrolyte layer.

7. An electrolyte layer having a surface on which the solid electrolyte according to claim 1 is arranged.

8. A secondary battery comprising the electrolyte layer according to claim 7, a positive electrode arranged to be in contact with the surface and configured to transfer lithium ions with the electrolyte layer, and a negative electrode in contact with the opposite surface of the electrolyte layer.

9. A solid electrolyte containing a borate oxide comprising Li, an element R selected from the group consisting of Yb, Er, Ho, Tm, and La, an element A selected from the group consisting of Al, Fe, Mn, and Ga, and an element M selected from the group consisting of Zr, Ce, and Sn.

10. The solid electrolyte according to claim 9, wherein the atomic concentration ratio [M] / ([R] + [A]) of the element M to the total of the element R and the element A is 0.05 or more and 0.43 or less.

11. The solid electrolyte according to claim 10, wherein the atomic concentration ratio [M] / ([R] + [A]) is 0.11 or more and 0.25 or less.

12. The solid electrolyte according to claim 9, wherein the atomic concentration ratio [A] / [R] of the element A to the element R is 0.05 or more and 0.50 or less.

13. The solid electrolyte according to claim 12, wherein the atomic concentration ratio [A] / [R] is 0.11 or more and 0.25 or less.

14. A solid electrolyte containing a borate oxide comprising Li, an element R selected from the group consisting of Yb, Er, Ho, Tm, and La, an element A selected from the group consisting of Al, Fe, Mn, and Ga, and an element M selected from the group consisting of Zr and Ce, and exhibiting two diffraction peaks in the range of diffraction angle 2θ of 28.0 degrees or more and 29.0 degrees or less in X-ray diffraction analysis using CuKα radiation, and the difference 2θd in diffraction angle between the diffraction peak on the high-angle side and the diffraction peak on the low-angle side is 0.416 degrees or more.

15. General formula Li ６－ｘ R １－ｙ－ａ A ｙ－ｂ M ｘ (BO ３ ) ３ A solid electrolyte containing an oxide represented by. However, in the formula, R is a rare earth element selected from Yb, Tm, Ho, Er, and La; A is a trivalent element selected from Al, Fe, Mn, and Ga; M is a tetravalent element selected from the group including Zr and Ce; a and b satisfy 0 ≦ a, b < 1 and a + b = x; and x and y are real numbers satisfying 0 < x, y < 1.

16. The solid electrolyte according to claim 14, which exhibits two diffraction peaks in the range of diffraction angle 2θ of 28.0 degrees or more and 29.0 degrees or less in X-ray diffraction analysis using CuKα rays, and the difference in diffraction angle 2θd between the diffraction peak on the high-angle side and the diffraction peak on the low-angle side is 0.416 degrees or more.

17. The solid electrolyte according to claim 9, wherein the element M contains Zr.

18. The solid electrolyte according to claim 17, wherein the element M further contains Ce.

19. The solid electrolyte according to claim 9, wherein the element R contains a plurality of rare earth elements.

20. The solid electrolyte according to claim 19, wherein the plurality of rare earth elements at least contain Yb.

21. The solid electrolyte according to claim 9, wherein the element R contains Yb, the A is Al, and in X-ray diffraction analysis using CuKα rays, a diffraction peak is exhibited in the range of diffraction angle 2θ of 28.0 degrees or more and 28.20 degrees or less.

22. The solid electrolyte according to claim 15, wherein the R contains Yb, the A is Al, the M contains Zr, and 0 < x < 1.

23. A positive electrode having the solid electrolyte according to claim 9 and a positive electrode active material in which lithium ions are transferred between the solid electrolyte and the positive electrode active material.

24. The positive electrode according to claim 23, which has a surface on which the solid electrolyte and the positive electrode active material are arranged side by side.

25. The positive electrode according to claim 24, An electrolyte layer disposed to contact the surface and configured to exchange lithium ions with the positive electrode. A secondary battery including a negative electrode that contacts the surface opposite to the side contacting the surface of the electrolyte layer.

26. An electrolyte layer having a surface on which the solid electrolytes described in Claim 9 are arranged.

27. A secondary battery including the electrolyte layer described in Claim 26, a positive electrode disposed to contact the surface and configured to exchange lithium ions with the electrolyte layer, and a negative electrode that contacts the surface opposite to the surface of the electrolyte layer.

28. A resin base, The solid electrolyte according to any one of Claims 1 to 4 provided in the resin base, And a laminate having the same.

29. A resin base, The solid electrolyte according to any one of Claims 9 to 13 provided in the resin base, And a laminate having the same.

30. A resin base, The solid electrolyte according to Claim 14 or 16 provided in the resin base, And a laminate having the same.

31. A resin base, The solid electrolyte according to Claim 15 or 22 provided in the resin base, And a laminate having the same.

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