A Li3YCl6-based anion-cation dual-doped electrolyte and its preparation method and application

Abstract

The present application provides a Li3YCl6-based anion-cation dual-doped electrolyte and its preparation method and application. The anion-cation dual-doped electrolyte is obtained by ball milling a cation source, an anion source and Li3YCl6 raw materials; the cation source includes a halide containing a cation; the cation includes at least one of indium, scandium and zirconium; the anion source includes a salt containing bromine. The present application selects an anion Br ‑ Cl ‑ Doping, while selecting cation In 3+ Sc 3+ 、Zr 4+ Y 3+ Ions are doped and anion and cation dual-doped electrolytes are prepared by high-energy ball milling, without the need for a sintering process, thus avoiding the influence of subsequent sintering on the lattice.

Description

Technical Field

[0001] The present application relates to the field of lithium battery technology, and in particular to a Li3YCl6-based anion-cation dual-doped electrolyte and its preparation method and application. Background Art

[0002] Lithium-ion batteries, due to their high energy density and high output power, are widely used in daily life and production. However, traditional lithium-ion batteries use flammable and explosive organic compounds as electrolytes, making them prone to failure. All-solid-state lithium-ion batteries offer the potential to significantly improve battery safety and address the flammability and explosiveness of these electrolytes. Among various solid-state electrolytes, halide solid electrolytes have garnered widespread attention due to their superior performance.

[0003] The general formula of halide solid electrolytes is Li3MX6 (M = In, Y, Sc, Er, etc.; X = Cl, Br, etc.), which have high ionic conductivity (10 -4 -10 -3 S cm -1 ), a wide electrochemical window, and good chemical stability with cathode materials. Notably, due to the high electronegativity of halogen atoms, they possess high oxidative stability, thus exhibiting excellent interfacial stability with 4V-class cathode active materials without the need for any coating. Li3YCl6 is a typical representative of halide solid electrolytes.

[0004] The ionic conductivity of Li3YCl6 at room temperature is 0.03-0.51×10 -3 mS·cm -1 Among them, Asano et al. reported the highest ionic conductivity (0.51×10 -3 mS·cm -1 ) of Li3YCl6 solid electrolyte (Adv.Mater.2018,30,1803075.). However, its ionic conductivity is comparable to other halide solid electrolytes, such as Li3YBr6 (0.72-1.7×10 -3 mS·cm -1 )、Li3InCl6(0.84-2.04×10 -3 mS·cm -1 ) is still relatively low compared to other materials (Energy Environ. Sci., 2020, 13, 1429-1461). However, theoretical calculations predict that the electrochemical stability window of Li3YCl6 is 0.62-4.21V, while that of Li3YBr6 is only 0.59-3.15V. Therefore, Li3YCl6 still has great development value.

[0005] Therefore, a new method is urgently needed to further improve the ionic conductivity of Li3YCl6 and promote its application in all-solid-state lithium-ion batteries. Summary of the Invention

[0006] In view of the above problems, this application proposes an anion-cation dual-doped electrolyte based on Li3YCl6; the anion Br - Cl - Doping, while selecting cation In 3+ Sc 3+ 、Zr 4+ Y 3+ Ions are doped and anion and cation dual-doped electrolytes are prepared by high-energy ball milling, which overcomes the shortcomings and defects mentioned in the background technology.

[0007] To achieve the above objectives, this application adopts the following technical solutions:

[0008] The invention of this application is to provide a Li3YCl6-based anion-cation dual-doped electrolyte, which is obtained by ball milling a cation source, an anion source and Li3YCl6 raw materials; the cation source includes a halide containing a cation; the cation includes at least one of indium, scandium and zirconium; and the anion source includes a bromine-containing salt.

[0009] Optionally, the molar ratio of cations to anions and cations in the dual-doped electrolyte is (0.001-0.2):1; the molar ratio of anions to anions and cations in the dual-doped electrolyte is (1-2):1.

[0010] Optionally, the molar ratio of cations to anions and cations in the dual-doped electrolyte is (0.01-0.2):1; the molar ratio of anions to anions and cations in the dual-doped electrolyte is (1.2-1.8):1.

[0011] Optionally, the cation-containing halide comprises a bromide and / or chloride of the cation; and the bromine-containing salt comprises a bromide and / or a bromate.

[0012] Another invention point of the present application is to provide a method for preparing any of the above-mentioned anion-cation dual-doped electrolytes.

[0013] Optionally, in vacuum or inert gas, the cation source, the anion source and the raw material of Li3YCl6 are mixed and then ball-milled to obtain the anion-cation dual-doped electrolyte.

[0014] Optionally, the ball milling time is ≥24 h.

[0015] Preferably, the ball milling time is ≥75 h.

[0016] Optionally, during ball milling, the process is stopped for 3 to 10 minutes after every 10 to 15 minutes; and then the process is ball milled for another 10 to 15 minutes and then stopped for 3 to 10 minutes.

[0017] Optionally, the ball-to-material ratio is (30-50):1; the rotation speed is 200-800 rpm.

[0018] Preferably, the ball-to-material ratio is (30-50):1; the rotation speed is 450-550 rpm.

[0019] Another invention point of the present application is to provide an application of any of the above-mentioned anion-cation dual-doped electrolytes in lithium-ion batteries.

[0020] Compared with the prior art, this application has the following beneficial effects:

[0021] (1) The present invention uses ball milling to dope Li3YCl6 with anions and cations, selects bromine to dope chlorine, cations indium, scandium, and zirconium to dope yttrium, and introduces anion vacancies or cation gaps and anion gaps or cation vacancies, causing the lattice to be distorted, generating more vacancies or gaps, and promoting Li + The transport of ions can construct a solid electrolyte with high ionic conductivity.

[0022] (2) The doping method of this application is ball milling, which does not require a sintering process, thus avoiding the influence of subsequent sintering on the lattice. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is the XRD pattern of the solid electrolyte of Experimental Examples 1 to 3 and Comparative Example 1 of the present application; the abscissa is the double diffraction angle, in degrees; the ordinate is the intensity, without units.

[0024] Figure 2 These are SEM images of the solid electrolytes of Test Examples 1 to 3 and Comparative Example 1 of this application.

[0025] Figure 3 Impedance diagram of the solid electrolyte of Test Examples 1 to 3 and Comparative Example 1 of the present application; the abscissa is Z′, i.e., the real part of the impedance, in Ω; the ordinate is -Z″, i.e., the imaginary part of the impedance, in Ω.

[0026] Figure 4 This is the impedance diagram of the solid electrolyte of Comparative Example 2 of the present application; the abscissa is Z′, i.e., the real part of the impedance, in Ω; the ordinate is -Z″, i.e., the imaginary part of the impedance, in Ω.

[0027] Figure 5 This is the impedance diagram of the solid electrolyte of Comparative Example 3 of the present application; the abscissa is Z′, i.e., the real part of the impedance, in Ω; the ordinate is -Z″, i.e., the imaginary part of the impedance, in Ω. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below. However, it should be understood that the description herein is only used to explain this application and is not intended to limit the scope of this application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended solely for the purpose of describing specific embodiments and are not intended to limit this application. The reagents and instruments used herein are commercially available, and the characterization methods involved can be found in the relevant descriptions in the prior art and will not be further elaborated herein.

[0030] In order to further understand the present application, the present application is further described in detail below in conjunction with the best embodiment.

[0031] Example 1

[0032] This embodiment provides a Li3YCl6-based anion-cation dual-doped electrolyte, which is obtained by ball milling a cation source, an anion source, and Li3YCl6 raw materials; the cation source includes a halide containing a cation; the cation includes at least one of indium, scandium, and zirconium; and the anion source includes a bromine-containing salt.

[0033] The cation doping elements may be one, two or three; for example, they may be doped with indium, scandium or zirconium individually; they may also be doped in pairs, indium and scandium co-doped, scandium and zirconium co-doped or indium and zirconium co-doped; they may also be co-doped with indium, scandium and zirconium.

[0034] The molar ratio of cations to anions and cations in a dual-doped electrolyte is (0.001-0.2):1. That is, the content of Y in the cation-substituted portion is between 0.001 and 0.2. Excessive doping can cause extensive damage to the Y crystals, destroying the main crystal structure. This will not only fail to improve the electrolyte's ionic conductivity, but will actually reduce its electrical properties.

[0035] Whether it is doping with individual indium, scandium, or zirconium, doping with two of them, or doping with three of them, the total doping content is between 0.001 and 0.2, so as to avoid damage to the main structure of Y.

[0036] The molar ratio of anions to anions and cations in the dual-doped electrolyte is (1-2):1.

[0037] Although bromine doping can increase anion vacancies or cation gaps, since the radius of bromine is larger than that of chlorine, excessive bromine doping will cause deformation or even rupture of the crystal structure, produce more impurities, and fail to maintain the crystal structure, thus affecting the Li+ The transport of ions is affected, further impacting ionic conductivity. Therefore, excessive bromine doping is not recommended. However, a small amount of doping will not be effective in increasing anion vacancies or cation interstitials. A molar ratio of (1-2):1 is optimal, for example, 1:1, 1.5:1, or 2:1.

[0038] That is, in the anion-cation dual-doped electrolyte, the ratio of bromine to chlorine is (1-2):(5-4), for example, it can be 1:5, 1.5:4.5 or 2:4.

[0039] The cation-containing halide includes bromide and / or chloride of the cation; the bromine-containing salt includes bromide and / or bromate.

[0040] Example 2

[0041] This embodiment provides a method for preparing an anion-cation dual-doped electrolyte. The anion-cation dual-doped electrolyte is the same as the anion-cation dual-doped electrolyte described in Example 1, and will not be described in detail here.

[0042] In vacuum or inert gas, a cation source, an anion source and a raw material of Li3YCl6 are mixed and ball milled to obtain the anion-cation dual-doped electrolyte.

[0043] The preparation method only requires ball milling of the materials, without the need for a sintering process.

[0044] The ball milling time is ≥ 75 h, for example, 75 h, 76 h, 77 h, 78 h, 79 h, 80 h, 90 h, 100 h or more. The ball milling process not only uniformly mixes the substances but also promotes mutual doping between the substances to form an anion-cation dual-doped electrolyte.

[0045] To further enhance the ball milling effect, the milling process can be paused for 3 to 10 minutes after every 10 to 15 minutes. After another 10 to 15 minutes of ball milling, the milling process can be paused for 3 to 10 minutes until the milling time is complete. This pause allows heat to be released, preventing excessive temperatures from damaging the crystal structure during the milling process. Furthermore, during this time, the various substances can be concentrated, avoiding problems such as incomplete reactions caused by uneven mixing at the beginning. This allows for smoother ball milling and results in a more satisfactory anionic and cationic dual-doped electrolyte.

[0046] The ball milling is preferably high energy ball milling.

[0047] The mass ratio of the ball material is (30-50):1, preferably 40:1.

[0048] The ball milling beads used in the ball milling are made of zirconium oxide, and the size of the ball milling beads can be any common size on the market, for example, Φ=3.5 and 10 mm.

[0049] The rotation speed during ball milling is 450 to 550 rpm, preferably 500 rpm.

[0050] Example 3

[0051] According to the content of this application, the anion-cation dual-doped electrolyte of Example 1 and the preparation method of Example 2 are specifically described as follows:

[0052] (To prevent oxidation of the material in the air, all filler sampling operations should be carried out in a glove box containing an Ar atmosphere)

[0053] Test Example 1

[0054] (1) LiCl, YCl3, InCl3, and LiBr with a molar ratio of 1.4:0.85:0.15:1.6 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0055] (2) The high-energy ball milling method was used for synthesis, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconia and had sizes of Ф=3, 5, and 10 mm. The rotation speed was 500 rpm, and the milling process was repeated for 15 minutes, followed by a 5-minute pause, and then reversed and opened. The total time was 78 hours. After 50 hours of milling, the ball mill was opened in a glove box and the sample was scraped off the wall to allow the sample to be mixed evenly again. Finally, a Li3YCl6-based anion-cation dual-doped electrolyte was obtained, in which the molar ratio of indium to the anion-cation dual-doped electrolyte was 0.15:1; and the molar ratio of bromine to the anion-cation dual-doped electrolyte was 1.6:1.

[0056] Test Example 2

[0057] (1) LiCl, YCl3, ScCl3, and LiBr with a molar ratio of 1.4:0.82:0.18:1.6 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0058] (2) The high-energy ball milling method was used for synthesis, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconia with sizes of Ф=3, 5 and 10 mm. The rotation speed was 500 rpm, and the milling process was repeated for 15 minutes, followed by a 5-minute pause and then reversed for a total of 78 hours. After milling for 50 hours, the milling jar was opened in a glove box and the sample was scraped off the wall to allow the sample to be mixed evenly again. Finally, a Li3YCl6-based anion-cation dual-doped electrolyte was obtained, in which the molar ratio of scandium to the anion-cation dual-doped electrolyte was 0.18:1; and the molar ratio of bromine to the anion-cation dual-doped electrolyte was 1.6:1.

[0059] Test Example 3

[0060] (1) LiCl, YCl3, ZrCl4, and LiBr with a molar ratio of 1.4:0.99:0.01:1.6 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0061] (2) The high-energy ball milling method was used for synthesis, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconium oxide with sizes of Ф=3, 5 and 10 mm. The rotation speed was 500 rpm, and the milling process was repeated for 15 minutes, followed by a 5-minute pause and then reversed for a total of 78 hours. After 50 hours of milling, the milling jar was opened in a glove box and the sample was scraped off the wall to allow the sample to be mixed evenly again. Finally, a Li3YCl6-based anion-cation dual-doped electrolyte was obtained, in which the molar ratio of zirconium to the anion-cation dual-doped electrolyte was 0.18:1; and the molar ratio of bromine to the anion-cation dual-doped electrolyte was 1.6:1.

[0062] Test Example 4

[0063] (1) LiCl, YCl3, InCl3, ScCl3, and LiBr with a molar ratio of 1.4:0.84:0.08:0.08:1.6 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0064] (2) The high-energy ball milling method was used for synthesis, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconia and had sizes of Ф=3, 5 and 10 mm. The rotation speed was 500 rpm, and the milling process was repeated for 15 minutes, then stopped for 5 minutes, and then reversed and opened. The total time was 78 hours. After 50 hours of milling, the ball mill was opened in the glove box and the sample was scraped off the wall to mix the sample evenly again. Finally, a Li3YCl6-based anion-cation dual-doped electrolyte was obtained, in which the molar ratio of cations (indium and scandium) to the anion-cation dual-doped electrolyte was 0.16:1 (indium 0.08, scandium 0.08); the molar ratio of bromine to the anion-cation dual-doped electrolyte was 1.6:1.

[0065] Test Example 5

[0066] (1) LiCl, YCl3, InCl3, ZrCl4, and LiBr with a molar ratio of 1.4:0.84:0.15:0.01:1.6 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0067] (2) The high-energy ball milling method was used for synthesis, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconium oxide with sizes of Ф=3, 5 and 10 mm. The rotation speed was 500 rpm, and the milling time was 78 h after 15 min of rest and 5 min of reversal. After 50 h of milling, the ball mill was opened in the glove box and the sample was scraped off the wall to mix the sample evenly again. Finally, a Li3YCl6-based anion-cation dual-doped electrolyte was obtained, in which the molar ratio of cations (indium, zirconium) to the anion-cation dual-doped electrolyte was 0.16:1 (indium 0.15, zirconium 0.01); the molar ratio of bromine to the anion-cation dual-doped electrolyte was 1.6:1.

[0068] Test Example 6

[0069] (1) LiCl, YCl3, ScCl3, ZrCl4, and LiBr with a molar ratio of 1.4:0.84:0.15:0.01:1.6 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0070] (2) The high-energy ball milling method was used for synthesis, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconium oxide with sizes of Ф=3, 5 and 10 mm. The rotation speed was 500 rpm, and the milling time was 78 h after 15 min of rest and 5 min of reversal. After 50 h of milling, the ball mill was opened in the glove box and the sample was scraped off the wall to mix the sample evenly again. Finally, a Li3YCl6-based anion-cation dual-doped electrolyte was obtained, in which the molar ratio of cations (scandium and zirconium) to the anion-cation dual-doped electrolyte was 0.16:1 (scandium 0.15, zirconium 0.01); the molar ratio of bromine to the anion-cation dual-doped electrolyte was 1.6:1.

[0071] Test Example 7

[0072] (1) LiCl, YCl3, InCl3, ScCl3, ZrCl4 and LiBr with a molar ratio of 1.4:0.84:0.08:0.07:0.01:1.6 were weighed separately in a glove box filled with Ar gas, and then the ball mill was sealed; (2) The synthesis was carried out by high-energy ball milling with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconium oxide with sizes of Φ = 3, 5 and 10 mm; the rotation speed was 500 rpm, and the ball milling was stopped every 15 minutes. 5min, reverse and open, the total time is 78h; after grinding for 50h, the ball mill is opened in the glove box, and the sample is scraped off the wall to make the sample evenly mixed again, and finally an anion-cation dual-doped electrolyte based on Li3YCl6 is obtained, wherein the molar ratio of cations (indium, scandium, zirconium) to the anion-cation dual-doped electrolyte is 0.16:1 (indium 0.08, scandium 0.07, zirconium 0.01); the molar ratio of bromine to the anion-cation dual-doped electrolyte is 1.6:1.

[0073] Test Example 8

[0074] (1) LiCl, YCl3, InCl3, ScCl3, ZrCl4 and LiBr with a molar ratio of 1.4:0.66:0.15:0.18:0.01:1.6 were weighed separately in a glove box filled with Ar gas, and then the ball mill was sealed; (2) The synthesis was carried out by high-energy ball milling with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconium oxide with sizes of Φ = 3, 5 and 10 mm; the rotation speed was 500 rpm, and the ball milling was stopped every 15 minutes. 5min, reverse and open, the total time is 78h; after grinding for 50h, the ball mill is opened in the glove box, and the sample is scraped off the wall to make the sample evenly mixed again, and finally an anion-cation dual-doped electrolyte based on Li3YCl6 is obtained, wherein the molar ratio of cations (indium, scandium, zirconium) to the anion-cation dual-doped electrolyte is 0.34:1 (indium 0.15, scandium 0.18, zirconium 0.01); the molar ratio of bromine to the anion-cation dual-doped electrolyte is 1.6:1.

[0075] Comparative Example 1

[0076] (1) LiCl and YCl3 with a mass ratio of 3:1 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0077] (2) The synthesis was carried out by high-energy ball milling method with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconia with sizes of Ф=3, 5 and 10 mm. The rotation speed was 500 rpm, and the milling process was repeated for 15 minutes, followed by a 5-minute pause and then reversed and opened. The total time was 78 hours. After 50 hours of milling, the ball mill was opened in the glove box and the sample was scraped off the wall to mix the sample evenly again, finally obtaining Li3YCl6.

[0078] Comparative Example 2

[0079] (1) LiCl, YCl3, and LaCl3 with a molar ratio of 3:0.9:0.1 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0080] (2) The high-energy ball milling method was used for synthesis, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconia with sizes of Ф=3, 5 and 10 mm. The rotation speed was 500 rpm, and the milling time was 78 h after 15 min of rotation and 5 min of rest. After 50 h of milling, the ball mill was opened in the glove box and the sample was scraped off the wall to mix the sample evenly again. Finally, a cation-doped electrolyte based on Li3YCl6 was obtained, in which the molar ratio of lanthanum to the doped electrolyte was 0.1:1.

[0081] Comparative Example 3

[0082] (1) LiCl, YCl3, and LiI with a molar ratio of 1.5:1:1.5 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0083] (2) The synthesis was carried out by high-energy ball milling method, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconia with sizes of Ф=3, 5 and 10 mm. The rotation speed was 500 rpm, and the milling time was 78 h after 15 min of rotation and 5 min of rest. The ball milling jar was opened in the glove box after 50 h of milling, and the sample was scraped off the wall to mix the sample evenly again. Finally, an anion-doped electrolyte based on Li3YCl6 was obtained, in which the molar ratio of iodine to the doped electrolyte was 1.5:1.

[0084] Comparative Example 4

[0085] (1) LiCl, YCl3, and LiF with a molar ratio of 2:1:1 were weighed separately in a glove box filled with Ar gas, and then the ball mill jar was sealed;

[0086] (2) The high-energy ball milling method was used for synthesis, with a ball-to-material mass ratio of 40:1. The ball milling beads were made of zirconia and had sizes of Ф = 3, 5, and 10 mm. The rotation speed was 500 rpm, and the milling time was 78 h after 15 min of rotation and 5 min of rest. After 50 h of grinding, the ball mill was opened in the glove box and the sample was scraped off the wall to mix the sample evenly again. However, the final result failed and the doped electrolyte could not be obtained.

[0087] Comparative Example 5

[0088] The method is consistent with that of Experimental Example 7, except that sintering is performed after ball milling. Specifically, the solid electrolyte is ground evenly and then placed in a tubular furnace for calcination at 400°C with argon for 10 hours to obtain a sintered anion-cation dual-doped electrolyte.

[0089] Performance Testing

[0090] (1) XRD test of the four solid electrolytes of Test Examples 1 to 3 and Comparative Example 1

[0091] from Figure 1 It can be seen that the sample after doping basically maintains the original crystal structure of the Li3YCl6 solid electrolyte. With the doping of Br atoms, it can be seen that the diffraction angle on the XRD pattern shifts to a smaller direction. This is because the atomic radius of Br is larger than the atomic radius of Cl. Therefore, it can be determined that Br is successfully doped in Experimental Examples 1 to 3.

[0092] (2) SEM characterization of the four solid electrolytes of Experimental Examples 1 to 3 and Comparative Example 1

[0093] from Figure 2 It can be seen from the above that the morphology of the four solid electrolytes is composed of particles of a few microns in size. With the doping of anions and cations, the particles of the electrolyte are further reduced, which can improve the Li + transport, thereby improving ionic conductivity.

[0094] (3) Impedance test of the solid electrolyte of the test example and the comparative example

[0095] The specific testing process is as follows: the solid electrolyte powder is loaded into an electrically insulating cylindrical cell with an inner diameter of 10 mm and then compressed at 300 MPa. The powder is sandwiched between two stainless steel electrodes. The sample weight is approximately 100 mg, and the thickness of the compressed powder is measured using a vernier caliper. The ionic conductivity value is calculated using the following formula:

[0096]

[0097] Where L is the thickness of the sample powder, R is the resistance value obtained by EIS measurement, and S is its surface area. The specific values ​​and ionic conductivity are shown in Table 1 and Figures 3-5 .

[0098] Table 1

[0099] Thickness (cm) Impedance (Ω) <![CDATA[Ionic conductivity (S·cm -1 )]]> Test Example 1 0.051 157 <![CDATA[4.14×10 -4 ]]> Test Example 2 0.044 213 <![CDATA[2.63×10 -4 ]]> Test Example 3 0.05 84.8 <![CDATA[7.51×10 -4 ]]> Test Example 7 0.048 110 <![CDATA[5.56×10 -4 ]]> Test Example 8 0.051 347 <![CDATA[1.87×10 -4 ]]> Comparative Example 1 0.064 532 <![CDATA[1.53×10 -4 ]]> Comparative Example 2 0.061 830 <![CDATA[9.36×10 -5 ]]> Comparative Example 3 0.037 7200 <![CDATA[6.55×10 -6 ]]> Comparative Example 5 0.05 349 <![CDATA[1.83×10 -4 ]]>

[0100] As shown in Table 1 and Figure 3As shown, the ionic conductivity of the experimental examples of the present application is higher than that of the comparative example 1, indicating that the doping of anions and cations selected in the present application will improve the corresponding performance. However, according to the data of experimental examples 1 to 3 and experimental example 7, when multiple cations are doped, the improvement of ionic conductivity is more obvious. This is because multiple cations will make the types of anion vacancies or cation gaps richer, thereby promoting Li + The transmission of the test examples 4 to 6 has a better effect.

[0101] Comparing Experimental Example 7 with Experimental Example 8, it can be seen that when the cation doping is no more than 0.2, it will promote lattice distortion, but will not affect the main body of the crystal structure; when it is greater than 0.2, it will cause greater damage to the main structure of the crystal, thereby affecting the improvement of ionic conductivity, which is not much different from Li3YCl6 and cannot improve the corresponding performance.

[0102] According to Comparative Example 2 and Figure 4 It can be seen that not all cation doping can improve ionic conductivity, and only the cations selected in this application have these effects.

[0103] Comparative Examples 3 and 4 use iodine and fluorine for anion doping, respectively. Since fluorine doping cannot be achieved by ball milling, there is no relevant data for this comparative example. Figure 5 The data show that iodine doping cannot improve the ionic conductivity, indicating that the present application has a unique effect on the selection of anions, and not all anions, especially chlorine atoms, can achieve this effect.

[0104] After sintering, the ionic conductivity of Experimental Example 7 of the present application was found to be reduced. The reason may be that the high temperature caused the elements to rearrange, the crystal structure changed greatly, and more impurities were generated, which was not conducive to the Li + transmission, resulting in reduced performance.

[0105] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A Li3YCl6-based anion-cation dual-doped electrolyte, characterized in that: The anion-cation dual-doped electrolyte is obtained by ball milling a cation source, anion source and Li3YCl6 raw materials; The cation source is a halide containing cations; the cations include at least two of indium, scandium, and zirconium; the anion source is a bromine-containing salt; the cation-containing halide is a bromide and / or chloride of the cations; the bromine-containing salt is a bromide and / or bromate; the molar ratio of cations to anions and cations in a dual-doped electrolyte is (0.001-0.2):1; the molar ratio of anions to anions and cations in a dual-doped electrolyte is (1-2):

1.

2. The anion-cation dual-doped electrolyte according to claim 1, characterized in that: The molar ratio of cations to anions and cations in dual-doped electrolytes is (0.01~0.2):1; the molar ratio of anions to anions and cations in dual-doped electrolytes is (1.2~1.8):

1.

3. A method for preparing an anion-cation dual-doped electrolyte according to any one of claims 1 to 2, characterized in that: In vacuum or inert gas, a cation source, an anion source and a raw material of Li3YCl6 are mixed and ball milled to obtain the anion-cation dual-doped electrolyte.

4. The preparation method according to claim 3, characterized in that The ball milling time should be ≥24 h.

5. The preparation method according to claim 3, characterized in that During ball milling, stop for 3-10 minutes after every 10-15 minutes; then, ball mill for another 10-15 minutes and then stop for 3-10 minutes.

6. The preparation method according to claim 3, characterized in that The ball-to-material ratio is (30~50):1; the rotation speed is 200~800rpm.

7. Use of the anion-cation dual-doped electrolyte according to any one of claims 1 to 2 in a lithium-ion battery.

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