CN102044700B - Lithium lanthanum bismuthate-based solid electrolyte material and preparation method thereof - Google Patents

Abstract

The invention discloses a bismuth lanthanum lithium-based solid electrolyte material and a preparation method thereof. The material is lanthanum-lithium bismuth-based lanthanum-site and bismuth-site doped chemical formula is La _3-X A _X Li _5+δ Bi _2-Y B _Y O ₁₂ , A in the chemical formula is the lanthanum-site dopant, x _{0 to} 1.25, B is a bismuth dopant, and _y is 0 to 1.25; the method is to weigh lithium _{, lanthanum ,} Bismuth, lanthanum dopant and/or bismuth dopant nitrate or carbonate or chloride or acetate or alkoxide or oxide soluble in acid are formulated into solution, firstly add lithium salt Add lanthanum salt solution, bismuth salt solution, lanthanum dopant solution and/or bismuth dopant solution dropwise into the solution, then add citric acid and nitric acid to it in order to obtain a sol, and then add water-soluble high The molecular polymer forms a gel, and then the gel is dried and then heat-treated to obtain a nanocrystalline powder, which is then molded into a green body and then calcined to prepare a lanthanum lithium bismuthate-based solid electrolyte material. It can be used as a solid-state electrolyte material for all-solid-state lithium-ion batteries.

Description

Lanthanum lithium bismuth-based solid-state electrolyte material and preparation method thereof

technical field

The invention relates to a solid electrolyte material and a preparation method, in particular to a lanthanum bismuth lithium-based solid electrolyte material and a preparation method thereof.

Background technique

All-solid-state lithium-ion battery is a new generation of lithium-ion battery recently developed. Compared with the current commercial lithium battery, it has the advantages of easy miniaturization, good safety performance, easy processing, and no battery internal pressure. It can effectively eliminate the traditional Liquid electrolyte lithium-ion batteries have safety problems such as flammability, volatility, electrolyte leakage, and poor heat resistance, and it is expected to use metal lithium as the negative electrode to greatly increase the specific capacity of the battery. Therefore, all-solid-state lithium-ion batteries are expected to have broad application prospects in fields requiring high safety such as microelectronic devices and microsensors. At present, people have made some attempts and efforts in order to obtain all-solid-state lithium-ion batteries. For example, in the "Lithium Inorganic Solid Electrolyte" article published in March 2003 in "Chemical Progress", Volume 15, No. 2, a Lithium lanthanum titanate and its analogues. This kind of lanthanum lithium titanate with a perovskite structure and lithium inorganic solid electrolyte materials with similar structures have disadvantages. First, although the bulk conductivity at 25°C is 10 ^-3 S/cm, it is comparable to the existing ones. The practical polymer liquid electrolyte is comparable, but its grain boundary resistance is as high as 50 times the bulk resistance, resulting in a total conductivity of only 10 ^-5 S/cm at room temperature; secondly, poor electrochemical stability , when it is in direct contact with metal lithium, the two will undergo a redox reaction, resulting in the reduction of Ti ⁴⁺ to Ti ³⁺ , resulting in a higher electronic conductivity, so it is not suitable as an electrolyte in an all-solid-state lithium-ion battery ; Again, the synthesis temperature for preparing it is too high, reaching 1300° C., such a high preparation and synthesis temperature causes a large loss of lithium oxide, and makes it difficult to control the components of titanium, lanthanum and lithium.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a lithium bismuthate-based solid electrolyte material with good electrochemical stability.

Another technical problem to be solved by the present invention is to provide a method for preparing a lithium lanthanum bismuthate-based solid electrolyte material with a low synthesis temperature during preparation.

In order to solve the technical problem of the present invention, the adopted technical scheme is: the lanthanum lithium bismuth acid base solid electrolyte material comprises the lanthanum lithium bismuth acid base with La ₃ Li ₅ Bi ₂ O ₁₂ chemical formula composition, especially,

The chemical formula after doping the lanthanum and bismuth sites of the lanthanum lithium bismuthate base is La _3-X A _X Li _5+δ Bi _2-Y B _Y O ₁₂ , and A in the chemical formula is a lanthanum-site dopant, It is barium (Ba) or calcium (Ca) or potassium (K) or a rare earth element, x is 0-1.25, B is a bismuth dopant, which is indium (In) or vanadium (V) or tantalum (Ta) Or niobium (Nb) or antimony (Sb), y is 0-1.25.

As a further improvement of the lanthanum lithium bismuth-based solid electrolyte material, the grain diameter of the La _3-X A _X Li _5+δ Bi _2-Y B _Y O ₁₂ is 2-10 μm; the rare earth element is praseodymium (Pr) or neodymium (Nd) or yttrium (Y) or cerium (Ce) or samarium (Sm) or gadolinium (Gd).

In order to solve another technical problem of the present invention, another technical scheme adopted is: the preparation method of lanthanum bismuth lithium-based solid electrolyte material comprises a sol-gel method, and the particularly finishing steps are as follows,

Step 1, according to the composition ratio of La _3-X A _X Li _5+δ Bi _2-Y B _{YO 12} , weigh the corresponding amount of lithium, lanthanum, bismuth, lanthanum dopant and/or bismuth dopant Nitrate or carbonate or chloride or acetate or alkoxide or oxides soluble in acid, and add them to the solvent to prepare the corresponding solution, first place it at 30 ~ 100 ℃, Add dropwise lanthanum salt solution, bismuth salt solution, lanthanum dopant solution and/or bismuth dopant solution to the stirred lithium salt solution to obtain a mixed solution with a total metal ion concentration of 0.1 to 10 mol/L, and then add After adding citric acid to the mixed solution and stirring, wherein the molar ratio of citric acid to the total metal ions in the mixed solution is 0.5-2:1, then, after adding nitric acid to adjust the pH value to 0.5-5, it is placed in Stir at 30-100°C for 1-2 hours to obtain a transparent and clear sol;

Step 2, after adding a water-soluble polymer to the sol, place it at 30-100°C and stir until a gel is formed, wherein the mass ratio of the water-soluble polymer to citric acid is 1-2:1 ~40;

Step 3, first place the gel at 80-100°C to dry for 22-26 hours to obtain a fluffy xerogel, then heat-treat the xerogel at 600-800°C for 2-10 hours to obtain a nanocrystalline powder, then First, the nanocrystalline powder is molded into a green body, and then placed at 730-800 ° C for 5-10 hours to calcinate to prepare a lithium-bismuth-based solid electrolyte material.

As a further improvement of the preparation method of lanthanum lithium bismuth-based solid electrolyte material, the solvent is water or ethanol or ethylene glycol or a mixture of two or more of the foregoing; the corresponding solution is a corresponding clear solution; the The water-soluble polymer mentioned above is polyethylene glycol or polyvinyl alcohol or polyvinyl pyrrolidone; The heating rate is 0.5-4° C./min; the grain diameter of the nanocrystalline powder is 50-200 nm.

Compared with the beneficial effects of the prior art, firstly, the obtained product is characterized by field emission scanning electron microscope and X-ray diffractometer respectively. It can be known from the results that the grain diameter of the product is 2-10 μm, and the product It is composed of lanthanum bismuth lithium base doped with lanthanum and/or bismuth. The chemical formula after doping is La _3-X A _X Li _5+δ Bi _2-Y B _Y O ₁₂ , and A in the chemical formula is lanthanum Position dopant, it is barium or calcium or potassium or rare earth element, x is 0-1.25, B is bismuth position dopant, it is indium or vanadium or tantalum or niobium or antimony, y is 0-1.25, rare earth element It is praseodymium or neodymium or yttrium or cerium or samarium or gadolinium. Lanthanum lithium bismuthate is a typical garnet structure; second, after testing, the total conductivity of the product at room temperature is 10 ^-5 ~ 10 ^-4 S/cm, compared with the existing lithium lanthanum titanate and similar structures The room temperature total conductivity of lithium inorganic solid electrolyte materials has been improved to a certain extent, and there is no phenomenon similar to that in lithium lanthanum titanate that reacts with metal lithium to reduce Ti ⁴⁺ to Ti ³⁺ to produce electronic conductance; its Third, the temperature of heat treatment and calcination during the preparation of the product is low, the highest is only 800°C, which is much lower than 1300°C, which will not cause a large loss of lithium oxide, so that the components of titanium, lanthanum and lithium are very easy to control; other Fourth, the doping process is easy to control the chemical composition of the product conveniently and accurately, conveniently realize the doping of various components and contents, the time for heat treatment and calcination is short, the operation process is convenient, and it is suitable for large-scale industrial production.

As a further manifestation of beneficial effects, firstly, the grain diameter of La _3-X A _X Li _5+δ Bi _2-Y B _Y O ₁₂ is preferably 2-10 μm, which is beneficial for it to be used as a solid electrolyte material for all-solid-state lithium-ion batteries The second is that the doped rare earth element is preferably praseodymium or neodymium or yttrium or cerium or samarium or gadolinium, which not only makes the source of raw materials more abundant, but also makes the preparation process easier to implement and flexible; the third is that the solvent is preferably water or ethanol or ethylene glycol Or aforementioned two or more mixed solutions, the water-soluble polymer is preferably polyethylene glycol or polyvinyl alcohol or polyvinylpyrrolidone, which not only makes the selection of the solvent and the water-soluble polymer more room for maneuver, It is also beneficial to the preparation of products; Fourth, the pressure of uniaxial molding is preferably 150-600 MPa, which is easy to form products.

Description of drawings

The preferred modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 is one of the SEM photos taken after using a field emission scanning electron microscope (SEM) to observe the morphology of numerous intermediates-nanocrystalline powders and products prepared. Among them, Fig. 1a and Fig. 1b are SEM photos of the nanocrystalline powder, from which it can be seen that the particle size of the nanocrystalline powder is relatively uniform, and its grain diameter is 50-200nm. Figure 1c and Figure 1d are SEM photos of the product, from which it can be seen that the crystal grain diameter of the product is 2-10 μm.

Fig. 2 is one of the XRD spectrograms obtained after using an X-ray diffraction (XRD) instrument to test many products prepared. It can be seen from the XRD spectrum that the product is a lithium bismuthate-based solid electrolyte material doped with calcium at the lanthanum site.

Fig. 3 is one of the AC impedance spectrograms obtained after using an AC impedance meter to test many of the prepared products. From the AC impedance spectrum, the grain resistance and grain boundary resistance of the product at the test temperature can be obtained by fitting, and then the conductivity value of the product can be obtained through the following formula

$\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; l</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; gi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; gb</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ,</span>$

In the formula, l is the thickness of the product, S is the electrode area on the surface of the product, R _gi is the grain resistance, and R _gb is the grain boundary resistance.

Detailed ways

Firstly, the nitrate, carbonate, chloride, acetate, alkoxide of lithium, lanthanum, bismuth, lanthanum dopant and bismuth dopant are prepared by conventional method or purchased from the market and can be used in acid Soluble oxide, in which the lanthanum dopant is barium, calcium, potassium and rare earth elements, the bismuth dopant is indium, vanadium, tantalum, niobium and antimony, and the rare earth element is praseodymium, neodymium, yttrium, cerium, samarium and gadolinium, water, ethanol, ethylene glycol, and a mixture of two or more of the above solvents, and polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone as water-soluble polymers. then,

Example 1

The concrete steps of preparation are:

Step 1, according to the composition ratio of La _3-X A _X Li _5+δ Bi _{2-Y B} YO ₁₂ , where x is 0 and y is 1.25, weigh the corresponding amount of lithium, lanthanum, bismuth and bismuth doped Nitrates or carbonates or chlorides or acetates or alkoxides or oxides soluble in acid, which are added to solvents to prepare corresponding solutions; among them, lithium, lanthanum, bismuth and bismuth-site dopants are their nitrates, specifically lithium nitrate, lanthanum nitrate, bismuth nitrate and indium nitrate, the solvent is water, and the corresponding solution is a corresponding clear solution. First add the lanthanum salt solution, the bismuth salt solution and the bismuth dopant solution dropwise to the lithium salt solution placed at 30°C under stirring, wherein the lithium salt solution is lithium nitrate solution, the lanthanum salt solution is lanthanum nitrate solution, bismuth The salt solution is a bismuth nitrate solution, the bismuth dopant solution is an indium nitrate solution, and a mixed solution with a total metal ion concentration of 0.1 mol/L is obtained. Then add citric acid to the mixed solution and stir, wherein the molar ratio of citric acid to the total metal ions in the mixed solution is 0.5:1. Next, after nitric acid was added thereto to adjust the pH to 0.5, it was placed at 30° C. and stirred for 2 hours to obtain a transparent and clear sol.

Step 2, after adding a water-soluble polymer to the sol, it is placed at 30°C and stirred until a gel is formed; wherein, the mass ratio of the water-soluble polymer to citric acid is 1:40, and the water solubility is high The molecular polymer is polyethylene glycol.

Step 3, first dry the gel at 80°C for 26 hours to obtain a fluffy dry gel, and then heat-treat the dry gel at 600°C for 10 hours; the heating rate is 0.5°C/ min, the nanocrystalline powder similar to that shown in Figure 1a and Figure 1b is obtained. Next, the nanocrystalline powder is first molded into a green body; wherein, the molding is uniaxial pressing, and the forming pressure is 150 MPa. It was then calcined at 730° C. for 10 h to prepare a lithium bismuthate-based solid electrolyte material similar to that shown in Figure 1c and Figure 1d , and similar to the curves shown in Figure 2 and Figure 3 .

Example 2

The concrete steps of preparation are:

Step 1, according to the composition ratio of La _3-X A _X Li _5+δ Bi _{2-Y B} YO ₁₂ , where x is 0.1 and y is 0.8, weigh the corresponding amount of lithium, lanthanum, bismuth, lanthanum doped Nitrate or carbonate or chloride or acetate or alkoxide or acid-soluble oxides of sundries and bismuth-site dopants are added to solvents to prepare corresponding solutions; Lithium, lanthanum, bismuth, lanthanum dopant and bismuth dopant are all their nitrates, specifically lithium nitrate, lanthanum nitrate, bismuth nitrate, calcium nitrate and indium nitrate, the solvent is water, and the corresponding solution is the corresponding clear solution. First, add lanthanum salt solution, bismuth salt solution, lanthanum dopant solution and bismuth dopant solution dropwise to the lithium salt solution placed at 50°C under stirring, wherein the lithium salt solution is lithium nitrate solution, lanthanum salt solution The solution is lanthanum nitrate solution, the bismuth salt solution is bismuth nitrate solution, the lanthanum dopant solution is calcium nitrate solution, the bismuth dopant solution is indium nitrate solution, and a mixed solution with a total metal ion concentration of 0.8 mol/L is obtained. Then add citric acid to the mixed solution and stir, wherein the molar ratio of citric acid to the total metal ions in the mixed solution is 0.8:1. Next, nitric acid was added thereto to adjust the pH value to 1, and then placed at 50° C. and stirred for 1.8 h to obtain a transparent and clear sol.

Step 2, after adding a water-soluble polymer to the sol, it is placed at 50°C and stirred until a gel is formed; wherein, the mass ratio of the water-soluble polymer to citric acid is 1.2:30, which is highly water-soluble The molecular polymer is polyethylene glycol.

Step 3, first dry the gel at 85°C for 25 hours to obtain a fluffy dry gel, and then heat-treat the dry gel at 650°C for 8 hours; the heating rate is 1°C/ min, the nanocrystalline powder similar to that shown in Figure 1a and Figure 1b is obtained. Next, the nanocrystalline powder is first molded into a green body; wherein, the molding is uniaxial pressing, and the forming pressure is 250 MPa. It was then calcined at 750° C. for 9 hours to prepare a lithium bismuthate-based solid electrolyte material similar to that shown in Figure 1c and Figure 1d and similar to the curves shown in Figure 2 and Figure 3 .

Example 3

The concrete steps of preparation are:

Step 1, according to the composition ratio of La _3-X A _X Li _5+δ Bi _2-Y B _{YO 12} , where x is 0.5 and y is 0, weigh the corresponding amount of lithium, lanthanum, bismuth and lanthanum doped Nitrates or carbonates or chlorides or acetates or alkoxides or oxides soluble in acid, which are added to solvents to prepare corresponding solutions; among them, lithium, lanthanum, bismuth and lanthanum-site dopants are its nitrates, specifically lithium nitrate, lanthanum nitrate, bismuth nitrate and calcium nitrate, the solvent is water, and the corresponding solution is a corresponding clear solution. First add the lanthanum salt solution, the bismuth salt solution and the lanthanum dopant solution dropwise to the lithium salt solution placed at 65°C under stirring, wherein the lithium salt solution is lithium nitrate solution, the lanthanum salt solution is lanthanum nitrate solution, bismuth The salt solution is a bismuth nitrate solution, the lanthanum dopant solution is a calcium nitrate solution, and a mixed solution with a total metal ion concentration of 3 mol/L is obtained. Then add citric acid to the mixed solution and stir, wherein the molar ratio of citric acid to the total metal ions in the mixed solution is 1.2:1. Next, after nitric acid was added thereto to adjust the pH to 3, it was placed at 65° C. and stirred for 1.5 h to obtain a transparent and clear sol.

Step 2, after adding a water-soluble polymer to the sol, place it at 65°C and stir until a gel is formed; wherein, the mass ratio of the water-soluble polymer to citric acid is 1.5:20, which is highly water-soluble The molecular polymer is polyethylene glycol.

Step 3, first dry the gel at 90°C for 24 hours to obtain a fluffy dry gel, and then heat-treat the dry gel at 700°C for 6 hours; the heating rate is 2°C/ min, the nanocrystalline powder as shown in Figure 1a and Figure 1b is obtained. Next, the nanocrystalline powder is first molded into a green body; wherein, the molding is uniaxial pressing, and the forming pressure is 350 MPa. Then it was calcined at 765° C. for 8 hours to prepare the lanthanum lithium bismuth oxide-based solid electrolyte material as shown in FIG. 1c and FIG. 1d , and the curves in FIG. 2 and FIG. 3 .

Example 4

The concrete steps of preparation are:

Step 1, according to the composition ratio of La _3-X A _X Li _5+δ Bi _{2-Y B} YO ₁₂ , where x is 0.8 and y is 0.4, weigh the corresponding amount of lithium, lanthanum, bismuth, lanthanum doped Nitrate or carbonate or chloride or acetate or alkoxide or acid-soluble oxides of sundries and bismuth-site dopants are added to solvents to prepare corresponding solutions; Lithium, lanthanum, bismuth, lanthanum dopant and bismuth dopant are all their nitrates, specifically lithium nitrate, lanthanum nitrate, bismuth nitrate, calcium nitrate and indium nitrate, the solvent is water, and the corresponding solution is the corresponding clear solution. First add dropwise lanthanum salt solution, bismuth salt solution, lanthanum dopant solution and bismuth dopant solution to the lithium salt solution placed at 80°C under stirring, wherein the lithium salt solution is lithium nitrate solution, lanthanum salt solution The solution is lanthanum nitrate solution, the bismuth salt solution is bismuth nitrate solution, the lanthanum dopant solution is calcium nitrate solution, the bismuth dopant solution is indium nitrate solution, and a mixed solution with a total metal ion concentration of 7mol/L is obtained. Then add citric acid to the mixed solution and stir, wherein the molar ratio of citric acid to the total metal ions in the mixed solution is 1.6:1. Next, after adding nitric acid therein to adjust the pH to 4.5, it was placed at 80° C. and stirred for 1.2 h to obtain a transparent and clear sol.

Step 2, after adding a water-soluble polymer to the sol, it is placed at 80°C and stirred until a gel is formed; wherein, the mass ratio of the water-soluble polymer to citric acid is 1.8:10, and the water solubility is high The molecular polymer is polyethylene glycol.

Step 3, first dry the gel at 95°C for 23 hours to obtain a fluffy xerogel, then heat-treat the xerogel at 750°C for 4 hours; the heating rate is 3°C/ min, the nanocrystalline powder similar to that shown in Figure 1a and Figure 1b is obtained. Next, the nanocrystalline powder is first molded into a green body; wherein, the molding is uniaxial pressing, and the forming pressure is 500 MPa. It was then calcined at 780° C. for 6 hours to prepare a lithium bismuthate-based solid electrolyte material similar to that shown in Figure 1c and Figure 1d , and similar to the curves shown in Figure 2 and Figure 3 .

Example 5

The concrete steps of preparation are:

Step 1, according to the composition ratio of La _3-X A _X Li _5+δ Bi _{2-Y B} YO ₁₂ , where x is 1.25 and y is 0.1, weigh the corresponding amount of lithium, lanthanum, bismuth, lanthanum doped Nitrate or carbonate or chloride or acetate or alkoxide or acid-soluble oxides of sundries and bismuth-site dopants are added to solvents to prepare corresponding solutions; Lithium, lanthanum, bismuth, lanthanum dopant and bismuth dopant are all their nitrates, specifically lithium nitrate, lanthanum nitrate, bismuth nitrate, calcium nitrate and indium nitrate, the solvent is water, and the corresponding solution is the corresponding clear solution. First, add lanthanum salt solution, bismuth salt solution, lanthanum dopant solution and bismuth dopant solution dropwise to the lithium salt solution placed at 100°C under stirring, wherein the lithium salt solution is lithium nitrate solution, lanthanum salt solution The solution is lanthanum nitrate solution, the bismuth salt solution is bismuth nitrate solution, the lanthanum dopant solution is calcium nitrate solution, the bismuth dopant solution is indium nitrate solution, and a mixed solution with a total metal ion concentration of 10mol/L is obtained. Then add citric acid to the mixed solution and stir, wherein the molar ratio of citric acid to the total metal ions in the mixed solution is 2:1. Next, after nitric acid was added thereto to adjust the pH to 5, it was placed at 100° C. and stirred for 1 h to obtain a transparent and clear sol.

Step 2, after adding a water-soluble polymer to the sol, it is placed at 100°C and stirred until a gel is formed; wherein, the mass ratio of the water-soluble polymer to citric acid is 2:1, and the water solubility is high The molecular polymer is polyethylene glycol.

Step 3, first dry the gel at 100°C for 22 hours to obtain a fluffy dry gel, and then heat-treat the dry gel at 800°C for 2 hours; the heating rate when the temperature is raised to 800°C for heat treatment is 4°C/ min, the nanocrystalline powder similar to that shown in Figure 1a and Figure 1b is obtained. Next, the nanocrystalline powder is first molded into a green body; wherein, the molding is uniaxial pressing, and the forming pressure is 600 MPa. It was then calcined at 800° C. for 5 h to prepare a lithium bismuthate-based solid electrolyte material similar to that shown in Figure 1c and Figure 1d, and similar to the curves shown in Figure 2 and Figure 3 .

Respectively select lithium, lanthanum, bismuth, lanthanum dopant and bismuth dopant nitrate or carbonate or chloride or acetate or alkoxide or oxide soluble in acid, wherein the lanthanum The site dopant is barium or calcium or potassium or rare earth elements, the bismuth site dopant is indium or vanadium or tantalum or niobium or antimony, and the rare earth element is praseodymium or neodymium or yttrium or cerium or samarium or gadolinium for lanthanum site doping Miscellaneous or bismuth doping or double doping, water or ethanol or ethylene glycol or a mixture of two or more of the above solvents, polyethylene glycol or polyvinyl alcohol or polyethylene as a water-soluble polymer Pyrrolidone, repeat the above-mentioned Examples 1-5, and also prepare the lanthanum lithium bismuthate-based solid electrolyte material as or similar to that shown in Figure 1, and as or similar to the curves shown in Figures 2 and 3.

Apparently, those skilled in the art can make various changes and modifications to the lithium lanthanum bismuth oxide-based solid electrolyte material and its preparation method of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (9)

1. a lithium lanthanum bismuthate-based solid electrolyte material comprises and intends it is carried out the La that has of doping treatment ₃Li ₅Bi ₂O ₁₂The basic configuration of the bismuthic acid lanthanum lithium base that chemical formula forms is characterized in that:

Chemical formula after mixing in the lanthanum position of described bismuthic acid lanthanum lithium base and bismuth position consists of La _3-XA _XLi _{5+ δ}Bi _2-YB _YO ₁₂, the A in the chemical formula is lanthanum position alloy, and it is barium or calcium or potassium or rare earth element, and x is that 0～1.25, B is bismuth position alloy, and it is indium or vanadium or tantalum or niobium or antimony, y is 0～1.25.

2. lithium lanthanum bismuthate-based solid electrolyte material according to claim 1 is characterized in that La _3-XA _XLi _{5+ δ}Bi _2-YB _YO ₁₂Crystal grain diameter be 2～10 μ m.

3. lithium lanthanum bismuthate-based solid electrolyte material according to claim 1 is characterized in that rare earth element is praseodymium, or neodymium, or yttrium, or cerium, or samarium, or gadolinium.

4. the preparation method of the described lithium lanthanum bismuthate-based solid electrolyte material of claim 1 comprises sol-gel process, it is characterized in that completing steps is as follows:

Step 1 is according to La _3-XA _XLi _{5+ δ}Bi _2-YB _YO ₁₂The composition ratio, take by weighing the lithium of respective amount, lanthanum, bismuth, the nitrate of lanthanum position alloy and/or bismuth position alloy or carbonate or chloride or acetate or alkoxide or soluble oxide in acid, and with its add respectively be mixed with corresponding solution in the solvent after, first to placing 30～100 ℃, drip the lanthanum salting liquid in the lithium salt solution under stirring, the bismuth salting liquid, lanthanum position alloy solution and/or bismuth position alloy solution, obtain the mixed solution that the metal ion total concentration is 0.1～10mol/L, stir after adding citric acid in the mixed solution again, wherein, the mol ratio of the total metal ion in citric acid and the mixed solution is 0.5～2: 1, then, to wherein adding after the nitre acid for adjusting pH value is 0.5～5, be placed on 30～100 ℃ of lower 1～2h of stirring, obtain the colloidal sol of transparent clear;

Step 2, add high molecular weight water soluble polymer in the colloidal sol after, be placed on and be stirred to the formation gel under 30～100 ℃, wherein, the mass ratio of high molecular weight water soluble polymer and citric acid is 1～2: 1～40;

Step 3, first gel is placed 80～100 ℃ of lower dry 22～26h, obtain fluffy xerogel, again xerogel is placed 600～800 ℃ of lower heat treatment 2～10h, obtain nanocrystalline powder, then, first nanocrystalline powder is molded into base substrate, be placed on again 730～800 ℃ of lower calcining 5～10h, make lithium lanthanum bismuthate-based solid electrolyte material.

5. the preparation method of lithium lanthanum bismuthate-based solid electrolyte material according to claim 4 is characterized in that solvent is water, or ethanol, or ethylene glycol, or aforementioned two or more mixed liquor.

6. the preparation method of lithium lanthanum bismuthate-based solid electrolyte material according to claim 4 is characterized in that high molecular weight water soluble polymer is polyethylene glycol, or polyvinyl alcohol, or polyvinylpyrrolidone.

7. the preparation method of lithium lanthanum bismuthate-based solid electrolyte material according to claim 4 is characterized in that mold pressing is that single shaft is pressed, and the pressure of its shaping is 150～600MPa.

8. the preparation method of lithium lanthanum bismuthate-based solid electrolyte material according to claim 4, the heating rate when it is characterized in that being warming up to 600～800 ℃ of heat treatment is 0.5～4 ℃/min.

9. the preparation method of lithium lanthanum bismuthate-based solid electrolyte material according to claim 4, the crystal grain diameter that it is characterized in that nanocrystalline powder is 50～200nm.

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