Halide solid electrolyte and preparation method and application thereof

Abstract

The invention provides a halide solid electrolyte as well as a preparation method and application thereof, and particularly relates to the technical field of lithium batteries. The chemical formula of the halide solid electrolyte is Li < 2.8 > In M X < 6 >, m is a doping element and is selected from at least one of Nb, Ta, Zr, Mo, W, Gd, Al, Sc, Sb, Sn and V; x is halogen and is selected from at least one of F, Cl, Br and I; a and b satisfy 3a + mb = 3.2, wherein m is the valence state of M. According to the halide solid electrolyte provided by the invention, In is partially replaced by the doping element, a cation vacancy is introduced by the high valence state of the doping element, a three-dimensional diffusion channel of lithium ions is expanded, and the ionic conductivity of the solid electrolyte at room temperature is improved; meanwhile, halide generates a stable halogen-rich interface layer on the surface of the positive electrode in situ, so that side reaction is inhibited, and the cycle performance is improved. The halide solid electrolyte is better matched with a positive electrode material, the loading capacity and the reversible capacity of a positive electrode active material can be further improved, and the energy density of the battery is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium batteries, in particular to a halide solid-state electrolyte and a preparation method and application thereof. BACKGROUND

[0002] In recent years, all-solid-state lithium ion batteries have become the focus of research for next-generation energy storage technology due to their higher safety, expected energy density improvement, and long cycle life. Among them, the solid-state electrolyte is the key material that determines its performance: compared with the liquid system, it does not contain flammable solvents, can eliminate the risk of liquid leakage and inhibit dendrite penetration, thereby fundamentally improving the safety and reliability of the battery.

[0003] However, in the inorganic solid-state electrolyte system represented by halides, the following bottlenecks still exist: 1. The room temperature ionic conductivity has not reached the level of liquid electrolytes; 2. The interface stability with the positive active material is insufficient, resulting in continuous increase in interface impedance; Therefore, the present application is proposed. SUMMARY

[0004] The present application aims to provide a halide solid-state electrolyte and a preparation method and application thereof, and at least one of the above technical problems in the prior art is solved.

[0005] In order to achieve the above-mentioned purpose of the present application, the following technical solutions are adopted: The first aspect of the present application provides a halide solid-state electrolyte, the chemical formula of which is Li 2.8 In a M b X6; wherein M is a doping element, selected from at least one of Nb, Ta, Zr, Mo, W, Gd, Al, Sc, Sb, Sn and V; X is a halogen, selected from at least one of F, Cl, Br and I.

[0006] a and b satisfy 3a+mb=3.2, wherein m is the valence state of M.

[0007] Further, the chemical formula of the halide solid-state electrolyte is Li 2.8 In a Nb b X6, wherein 3a+5b=3.2.

[0008] Further, the chemical formula of the halide solid-state electrolyte is Li 2.8 In 0.9 Nb 0.1 X6.

[0009] Further, in the halide solid-state electrolyte, X is selected from two of F, Cl, Br and I.

[0010] Preferably, X is selected from F and Cl.

[0011] The second aspect of the present application provides a preparation method of the halide solid-state electrolyte, wherein LiX, InX and MX are weighed according to a stoichiometric ratio, mixed uniformly, and then ball milled under inert gas protection; and the ball milled product is pressed into a tablet and calcined to obtain the halide solid-state electrolyte.

[0012] Further, the ball milling speed is 300-800 rpm, and the ball milling time is 12-24 h.

[0013] Preferably, the ratio of the bead material in the ball milling is 20-40:1.

[0014] Preferably, the ball milling process is: according to the process cycle of forward rotation, intermittent, reverse rotation and intermittent.

[0015] Preferably, the time of forward rotation or reverse rotation is 20-40 min.

[0016] Preferably, the intermittent time is 3-8 min.

[0017] Further, the tablet pressing pressure is 18-22 MPa, and the pressure holding time is 1-5 min.

[0018] Preferably, the calcination temperature is 200-300℃, and the calcination time is 4-10 h.

[0019] Preferably, the calcination temperature is 200-300℃, and the calcination time is 4-10 h.

[0020] The third aspect of the present application provides an application of the halide solid-state electrolyte in a lithium ion solid-state battery.

[0021] Compared with the prior art, the present application has at least the following beneficial effects: The halide solid-state electrolyte provided by the present application uses a doping element to partially replace In, the high valence state of the doping element introduces cation vacancies, expands the three-dimensional diffusion channel of lithium ions, and improves the ionic conductivity of the solid-state electrolyte at room temperature; at the same time, the halide generates a stable halogen-rich interface layer in situ on the surface of the positive electrode, suppresses the side reaction, and improves the cycle performance. The halide solid-state electrolyte has better matching with the positive electrode material, can further improve the loading capacity and reversible capacity of the positive electrode active material, and improves the energy density of the battery.

[0022] The preparation method provided by the application realizes atomic-level mixing through ball milling, and then tabletting and calcination, so that high-purity phase halide solid electrolyte can be generated in one step. The process utilizes mechanical-thermal synergy to simultaneously complete doping, vacancy construction and lattice densification, significantly improves ionic conductivity, and ensures that the electrolyte and high-voltage positive electrode form a stable interface, thereby providing a reliable material basis for subsequent high-load, long-cycle all-solid-state batteries.

[0023] The application of the halide solid electrolyte in lithium ion solid-state batteries, in view of the above-mentioned halide solid electrolyte which has high room temperature ionic conductivity, wide electrochemical window and stable interface formed in situ with high-nickel positive electrode, the lithium ion solid-state battery assembled therefrom exhibits higher energy density, better rate performance and longer cycle life, while completely eliminating the risk of liquid leakage and thermal runaway, significantly improving the safety and reliability of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0025] Figure 1 is the AC impedance diagram of Example 2; Figure 2 is the AC impedance diagram of Example 3; Figure 3 is the AC impedance diagram of Example 8; Figure 4 is the AC impedance diagram of Example 10; Figure 5 is the AC impedance diagram of Example 11; Figure 6 is the AC impedance diagram of Comparative Example 1; Figure 7 is the AC impedance diagram of Comparative Example 2; Figure 8 is the AC impedance diagram of Comparative Example 3; Figure 9 is the AC impedance diagram of Comparative Example 4; Figure 10 is the AC impedance diagram of Comparative Example 5; Figure 11 is the scanning electron microscope (SEM) diagram of Example 2. DETAILED DESCRIPTION

[0026] In order to make the objects, technical solutions and advantages of the present application clearer, the following will combine the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application.

[0027] Hereinafter, the terms “include”, “have”, and their synonymous words used in various embodiments of the present application are only intended to indicate that specific features, numbers, steps, operations, elements, components, or combinations thereof are present, and should not be understood as excluding the possibility of existence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations thereof.

[0028] The first aspect of the present application provides a halide solid-state electrolyte, with a chemical formula of Li 2.8 In a M b X6; wherein M is a doping element, selected from at least one of Nb, Ta, Zr, Mo, W, Gd, Al, Sc, Sb, Sn, and V; and X is a halogen, selected from at least one of F, Cl, Br, and I.

[0029] a and b satisfy 3a+mb=3.2, wherein m is the valence state of M.

[0030] The halide solid-state electrolyte provided by the present application uses a doping element to partially replace In, and the high valence state of the doping element introduces cation vacancies, expands the three-dimensional diffusion channel of lithium ions, and improves the ionic conductivity of the solid-state electrolyte at room temperature. At the same time, the halide generates a stable halogen-rich interfacial layer in situ on the surface of the positive electrode, suppresses the side reaction, and improves the cycle performance. The halide solid-state electrolyte has better matching with the positive electrode material, can further improve the loading capacity and reversible capacity of the positive electrode active material, and improve the energy density of the battery.

[0031] Further, the halide solid-state electrolyte has a chemical formula of Li 2.8 In a Nb b X6, wherein 3a+5b=3.2.

[0032] Further, the halide solid-state electrolyte has a chemical formula of Li 2.8 In 0.9 Nb 0.1 X6.

[0033] Further, in the halide solid-state electrolyte, the X is selected from two of F, Cl, Br, and I.

[0034] Preferably, the X is selected from F and Cl.

[0035] The second aspect of the present application provides a preparation method of the halide solid-state electrolyte, wherein LiX, InX and MX are weighed according to a stoichiometric ratio, uniformly mixed, and then ball milled under inert gas protection; and the ball milled product is pressed into a tablet and calcined to obtain the halide solid-state electrolyte.

[0036] The preparation method provided by the present application realizes atomic-level mixing through ball milling, and then the tablet is calcined to generate a high-purity phase halide solid-state electrolyte in one step. The process utilizes mechanical-thermal synergy to simultaneously complete doping, vacancy construction and lattice densification, significantly improves the ionic conductivity, and ensures the formation of a stable interface between the electrolyte and the high-voltage positive electrode, thereby providing a reliable material basis for subsequent high-load and long-cycle all-solid-state batteries.

[0037] Further, the rotation speed of the ball milling is 300-800 rpm, and the time is 12-24 h.

[0038] Typically but not limitedly, the rotation speed of the ball milling may be, for example, 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm or 800 rpm, or any value within the range of 300-800 rpm; and the total time of the ball milling may be, for example, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h or 24 h, or any value within the range of 12-24 h.

[0039] Preferably, the bead-to-material ratio in the ball milling is 20-40:1.

[0040] Typically but not limitedly, the bead-to-material ratio in the ball milling may be, for example, 20:1, 22:1, 24:1, 26:1, 28:1, 30:1, 32:1, 34:1, 36:1, 38:1 or 40:1, or any value within the range of 20-40:1.

[0041] Preferably, the ball milling process is a process cycle of forward rotation, intermittent, reverse rotation and intermittent.

[0042] Preferably, the time of the forward rotation or the reverse rotation is 20-40 min.

[0043] Typically but not limitedly, the time of a single forward rotation or a single reverse rotation may be, for example, 20 min, 25 min, 30 min, 35 min or 40 min, or any value within the range of 20-40 min.

[0044] Preferably, the time of the intermittent is 3-8 min.

[0045] Typically but not exclusively, the intermittent time between two adjacent positive and negative rotations can be, for example, 3 min, 4 min, 5 min, 6 min, 7 min or 8 min, or any value within the range of 3-8 min.

[0046] Further, the pressure for tabletting is 18-22 MPa, and the dwell time is 1-5 min.

[0047] Typically but not exclusively, the pressure for tabletting can be, for example, 18 MPa, 19 MPa, 20 MPa, 21 MPa or 22 MPa, or any value within the range of 18-22 MPa; and the dwell time can be, for example, 1 min, 2 min, 3 min, 4 min or 5 min, or any value within the range of 1-5 min.

[0048] Preferably, the temperature for calcination is 200-300℃, and the time is 4-10 h.

[0049] Typically but not exclusively, the temperature for calcination can be, for example, 200℃, 220℃, 240℃, 260℃, 280℃ or 300℃, or any value within the range of 200-300℃; and the calcination time can be, for example, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, or any value within the range of 4-10 h.

[0050] Preferably, the heating rate for calcination is 0.5-3℃ / min.

[0051] Typically but not exclusively, the heating rate for calcination can be, for example, 0.5℃ / min, 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min or 3℃ / min, or any value within the range of 0.5-3℃ / min.

[0052] The third aspect of the present application provides the application of the halide solid-state electrolyte in lithium ion solid-state batteries.

[0053] The application of the halide solid-state electrolyte in lithium ion solid-state batteries, in view of the above-mentioned halide solid-state electrolyte which has high room-temperature ionic conductivity, wide electrochemical window and stable interface formed in situ with high-nickel positive electrodes, the lithium ion solid-state battery assembled therefrom exhibits higher energy density, better rate performance and longer cycle life, while completely eliminating the risk of liquid leakage and thermal runaway, significantly improving the safety and reliability of the battery.

[0054] The present application will be further illustrated by the following specific examples and comparative examples, but it should be understood that these examples are only for a more detailed illustration and should not be understood as limiting the present application in any form. The raw materials used in the examples and comparative examples of the present application are carried out under conventional conditions or the conditions recommended by the manufacturer, unless otherwise specified. The reagents or instruments used are conventional products that can be obtained by commercial purchase, unless otherwise specified.

[0055] Example 1 This example provides a halide solid-state electrolyte with the chemical formula Li 2.8 In 0.9 Nb 0.1 Cl 5.8 F 0.2 , and the preparation process is as follows: (1) According to the stoichiometric ratio of Li 2.8 In 0.9 Nb 0.1 Cl 5.8 F 0.2 , weigh 2 g of LiCl, LiF, InCl3, and NbCl5 respectively, and transfer them to an agate mortar. Manually grind the powder mixture for 15 minutes.

[0056] (2) Transfer the uniform mixture obtained in step (1) to a zirconia jar with a ball-to-material ratio of 30:1, all using 5 mm zirconia beads, and then seal the zirconia jar with tape in an argon-filled glove box.

[0057] (3) Move the zirconia jar in step (2) to a planetary ball mill, rotate at 500 rpm, and ball mill for 18 hours. The ball milling process is cycled in the following way: forward rotation for 30 minutes, stop for 5 minutes, reverse rotation for 30 minutes, and stop for 5 minutes.

[0058] (4) Transfer the zirconia jar in step (3) to an argon-filled glove box, and press it into a sheet shape using a tablet press at room temperature. Apply a pressure of 20 MPa for 2 minutes.

[0059] (5) In an argon-filled glove box, move the sheet-shaped material obtained in step (4) to a quartz glass tube and seal it with a hydrogen flame.

[0060] (6) Move the quartz glass tube in step (5) to a muffle furnace, heat it to 260°C at a rate of 1°C / min, and calcine it for 6 hours. After natural cooling, a halide solid-state electrolyte is obtained. The ionic conductivity of the solid-state electrolyte is 1.55 mS / cm.

[0061] Example 2 This example provides a halide solid-state electrolyte with the chemical formula Li 2. 6 In0.8 Ta 0.2 Cl 5.9 Br 0.1 The preparation method is the same as that in Example 1, except that LiF is replaced by LiBr, NbCl5 is replaced by TaCl5, the ball-to-material ratio is 40:1, the ball milling time is 24 hours, the calcination temperature is 250 ℃, the heating rate is 2 ℃ / min, and the holding time is 5 hours. The ionic conductivity of the solid-state electrolyte is 3.48 mS / cm.

[0062] Example 3 This example provides a halide solid-state electrolyte with a chemical formula of Li 2.9 In 0.9 Zr 0.1 Cl 5.7 F 0.3 The preparation method is the same as that in Example 1, except that NbCl5 is replaced by ZrCl4, and the heating rate is 2 ℃ / min. The ionic conductivity of the solid-state electrolyte is 2.87 mS / cm.

[0063] Example 4 This example provides a halide solid-state electrolyte with a chemical formula of Li 2.4 In 0.7 Mo 0.3 Cl 5.8 I 0.2 The preparation method is the same as that in Example 1, except that LiF is replaced by LiI, NbCl5 is replaced by MoCl5, the ball milling time is 20 hours, the calcination temperature is 200 ℃, the heating rate is 2 ℃ / min, and the holding time is 5 hours. The ionic conductivity of the solid-state electrolyte is 2.16 mS / cm.

[0064] Example 5 This example provides a halide solid-state electrolyte with a chemical formula of Li 2.7 In 0.85 W 0.15 Cl 5.7 F 0.3 The preparation method is the same as that in Example 1, except that NbCl5 is replaced by WCl5, the ball milling time is 24 hours, the calcination temperature is 250 ℃, and the heating rate is 1 ℃ / min. The ionic conductivity of the solid-state electrolyte is 1.85 mS / cm.

[0065] Example 6 This example provides a halide solid-state electrolyte with a chemical formula of Li3In 0.95 Gd 0.05 Cl 5.8 I 0.2The preparation method is the same as in Example 1, except that LiF is replaced by LiI, NbCl5 is replaced by GdCl3, the ball milling time is 24 hours, the temperature increasing rate is 2 ℃ / min, and the holding time is 8 hours. The ionic conductivity of the solid-state electrolyte is 1.22 mS / cm.

[0066] Example 7 This example provides a halide solid-state electrolyte with the chemical formula Li3In 0.8 Al 0.2 Cl 5.9 Br 0.1 The preparation method is the same as in Example 1, except that LiF is replaced by LiBr, NbCl5 is replaced by AlCl3, the ball milling time is 22 hours, the calcination temperature is 230 ℃, and the holding time is 5 hours. The ionic conductivity of the solid-state electrolyte is 2.13 mS / cm.

[0067] Example 8 This example provides a halide solid-state electrolyte with the chemical formula Li3In 0.7 Sc 0.3 Cl 5.9 F 0.1 The preparation method is the same as in Example 1, except that NbCl5 is replaced by ScCl3, the ball milling time is 24 hours, the temperature increasing rate is 2 ℃ / min, and the holding time is 5 hours. The ionic conductivity of the solid-state electrolyte is 2.59 mS / cm.

[0068] Example 9 This example provides a halide solid-state electrolyte with the chemical formula Li3In 0.8 Sb 0.2 Cl 5.9 F 0.1 The preparation method is the same as in Example 1, except that NbCl5 is replaced by SbCl3, the calcination temperature is 280 ℃, and the holding time is 4 hours. The ionic conductivity of the solid-state electrolyte is 1.74 mS / cm.

[0069] Example 10 This example provides a halide solid-state electrolyte with the chemical formula Li 2.75 In 0.75 Sn 0.25 Cl 5.7 Br 0.3 The preparation method is the same as in Example 1, except that LiF is replaced by LiBr, NbCl5 is replaced by SnCl4, the ball milling time is 20 hours, the calcination temperature is 240 ℃, and the holding time is 8 hours. The ionic conductivity of the solid-state electrolyte is 2.03 mS / cm.

[0070] Example 11 This example provides a halide solid-state electrolyte with a chemical formula of Li3In 0.7 V 0.3 Cl 5.8 I 0.2 The preparation method is the same as that of Example 1, except that LiF is replaced by LiI, NbCl5 is replaced by VCl3, the ball milling time is 24 hours, and the heating rate is 5 ℃ / min. The ionic conductivity of the solid-state electrolyte is 2.41 mS / cm.

[0071] Comparative Example 1 This comparative example provides a halide solid-state electrolyte with a chemical formula of Li3InCl6, which is prepared as follows: (1) LiCl and InCl3 are weighed according to the stoichiometric ratio of Li3InCl6, and a total of 2 g is transferred to an agate mortar. The powder mixture is manually ground for 15 minutes.

[0072] (2) The uniform mixture obtained in step (1) is transferred to a zirconia jar, with a ball-to-powder ratio of 30:1, and all 5 mm zirconia beads are used. Then the zirconia jar is sealed with tape in an argon-filled glove box.

[0073] (3) The zirconia jar in step (2) is moved to a planetary ball mill, with a rotation speed of 500 revolutions per minute, and the ball milling time is 18 hours. The ball milling process is cycled in the following manner: forward rotation for 30 minutes, stop for 5 minutes, reverse rotation for 30 minutes, and stop for 5 minutes.

[0074] (4) The zirconia jar in step (3) is transferred to an argon-filled glove box, and a tablet is pressed at room temperature using a tablet press, with an applied pressure of 20 MPa and a pressure holding time of 2 minutes.

[0075] (5) The tablet-shaped material obtained in step (4) is moved to a quartz glass tube in an argon-filled glove box, and is sealed by a hydrogen flame.

[0076] (6) The quartz glass tube in step (5) is moved to a muffle furnace, and is heated to 260 ℃ at a heating rate of 1 ℃ / min for 6 hours. After natural cooling, a halide solid-state electrolyte is obtained. The ionic conductivity of the solid-state electrolyte is 0.84 mS / cm.

[0077] Comparative Example 2 This comparative example provides a halide solid-state electrolyte with a chemical formula of Li 2.8 In 0.9 Nb 0.1 Cl6, which is prepared in the same way as Comparative Example 1, except that NbCl5 is added according to the stoichiometric ratio. The ionic conductivity of the solid-state electrolyte is 0.98 mS / cm.

[0078] Comparative Example 3 This comparative example provides a halide solid-state electrolyte with the chemical formula Li3InCl6 5.8 F 0.2 The preparation method is the same as that of Comparative Example 1, except that LiF is added according to the stoichiometric ratio. The ionic conductivity of the solid-state electrolyte is 0.60 mS / cm.

[0079] Comparative Example 4 This comparative example provides a halide solid-state electrolyte with the chemical formula Li 2.9 In 0.9 Zr 0.1 6, the preparation method of which is the same as that of Comparative Example 1, except that ZrCl4 is added according to the stoichiometric ratio. The ionic conductivity of the solid-state electrolyte is 0.86 mS / cm.

[0080] Comparative Example 5 This comparative example provides a halide solid-state electrolyte with the chemical formula Li3InCl6 5.7 Br 0.3 The preparation method is the same as that of Comparative Example 1, except that LiBr is added according to the stoichiometric ratio. The ionic conductivity of the solid-state electrolyte is 0.92 mS / cm.

[0081] Test Example 1 About 100 mg of the halide solid-state electrolyte obtained above was placed in an insulating battery mold with a diameter of 10 mm, and was pressed at a pressure of 4 MPa for 1 minute, and then was integrally pressed to 38 MPa for 2 minutes to assemble a solid-state battery for testing ionic conductivity. Under this pressure, it was placed in a 25°C incubator, and the solid-state electrolytes obtained in the examples and comparative examples were tested by alternating current impedance using an electrochemical workstation (CHI 660E).

[0082] The ionic conductivity was calculated based on the formula where σ is the ionic conductivity, L is the thickness of the electrolyte material subjected to pressure, R is the resistance of the electrolyte material, and S is the surface area of the electrolyte material subjected to pressure.

[0083] The ionic conductivities obtained above were recorded in Table 1 below.

[0084] Table 1

[0085] As can be seen from Table 1, the ionic conductivity of the solid-state electrolyte obtained by simultaneously doping high-valence metals and non-metals in Li3InCl6 is significantly higher than that obtained by simply doping metal elements or halogen elements, which illustrates the effectiveness of the doping strategy.

[0086] The AC impedance plots of Examples 2, 3, 8-11 and Comparative Examples 1-5 correspond to as shown in FIGS. 1-5. Figures 1 to 10 As can be seen from FIGS. 1-5, the ionic conductivity of the examples is higher than that of the comparative examples, and the grain boundary resistance of the comparative examples is significantly higher than that of the examples, which can be the reason for the low ionic conductivity of the comparative examples. Figures 1 to 10

[0087] The SEM image of the halide solid-state electrolyte obtained in Example 2 is shown in FIG. 6. Figure 11

[0088] Test Example 2 The halide solid-state electrolyte obtained, conductive carbon fiber (VGCF) and ternary high-nickel positive electrode material N92 were manually ground into a composite positive electrode at a mass ratio of 28%, 2% and 70%. In the full battery test, 100 mg of LPSC sulfide electrolyte was first weighed and laid in an insulating battery mold with a diameter of 10 mm, then 20 mg of the halide solid-state electrolyte obtained above was laid on one side of the LPSC sulfide electrolyte and pressed under a pressure of 4 MPa for 1 minute, then 28.6 mg of the composite positive electrode material obtained was poured into one side of the electrolyte layer which had been pressed, and a pressure of 10 MPa was applied for 2 minutes, and finally 10 mg of lithium-silicon alloy was weighed as the battery negative electrode. Aluminum foil and copper foil were used as the positive and negative electrode current collectors, respectively, and the whole was pressed to 38 MPa for 2 minutes to assemble a full solid-state battery for testing.

[0089] The assembled full solid-state battery was placed in a 25°C constant temperature box, and the test conditions were: 0.1 C rate, voltage range 2.5 ~ 4.3 V vs . Li + / Li. The specific operation is: constant current charging to the upper cut-off voltage 4.3 V vs . Li + / Li at 0.1 C rate, and the charge specific capacity at this time was recorded as the initial charge specific capacity; constant current discharging from 4.3 V vs . Li + / Li to the lower cut-off voltage 2.5 V vs vs . Li + / Li, and the discharge specific capacity at this time was recorded as the initial discharge specific capacity.

[0090] The capacity retention rate after 100 cycles was: 100 cycle discharge specific capacity / first cycle discharge specific capacity * 100%.

[0091] The solid-state battery prepared above was subjected to electrical performance testing, including the initial charge specific capacity, the initial discharge specific capacity, and the capacity retention rate after 100 cycles, as shown in Table 2.

[0092] Table 2​​

[0093] As can be seen from Table 2, the sample of the embodiment with high ionic conductivity exhibits higher charge / discharge specific capacity, and the first circle charge-discharge efficiency can reach 90.2%, which is better than the best sample (81.4%) of the comparative example. In addition, the capacity retention rate of all the sample of the embodiment after 100 cycles is higher than 90%, which shows that the simultaneous doping of high-valence metal and non-metal in Li3InCl6 can improve the stability of the all-solid-state battery.

[0094] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present application, which are used to illustrate the technical solutions of the present application, but not to limit the same. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can make modifications or easily think of changes to the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features thereof within the technical range disclosed by the present application. Such modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A halide solid state electrolyte characterized in that, Li 2.8 In a M b X6; wherein M is a doping element selected from at least one of Nb, Ta, Zr, Mo, W, Gd, Al, Sc, Sb, Sn, and V; X is halogen selected from at least one of F, Cl, Br, and I; a and b satisfy 3a+mb=3.2, wherein m is the valence of M.

2. The halide solid state electrolyte of claim 1, wherein, Li 2.8 In a Nb b X6, where 3a + 5b = 3.

2.

3. The halide solid state electrolyte of claim 1, wherein, Li 2.8 In 0.9 Nb 0.1 X6.

4. The halide solid state electrolyte of claim 1, wherein, The X is selected from two of F, Cl, Br, and I; Preferably, the X is selected from F and Cl.

5. A method for producing the halide solid electrolyte according to any one of claims 1 to 4, characterized by, LiX, InX, and MX are weighed according to stoichiometric ratio, mixed uniformly, and then ball-milled under inert gas protection; after ball-milling, tabletting and calcination are performed to obtain the halide solid-state electrolyte.

6. The preparation method according to claim 5, characterized in that, The rotation speed of the ball-milling is 300-800 rpm, and the time is 12-24 h; Preferably, the ratio of the bead material in the ball-milling is 20-40:

1.

7. The preparation method according to claim 5, characterized in that, The ball-milling process is: according to the process cycle of forward rotation, intermittent, reverse rotation, and intermittent.

8. The preparation method according to claim 7, characterized in that, The time of the forward rotation or the reverse rotation is 20-40 min; Preferably, the time of the intermittent is 3-8 min.

9. The preparation method according to claim 5, characterized in that, The pressure of the tabletting is 18-22 MPa, and the pressure maintaining time is 1-5 min; Preferably, the temperature of the calcination is 200-300℃, and the time is 4-10 h; Preferably, the heating rate of the calcination is 0.5-3℃ / min.

10. Application of the halide solid-state electrolyte according to any one of claims 1-4 in a lithium ion solid-state battery.

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