Preparation of nitrogen-chlorine-based halide electrolyte and application of nitrogen-chlorine-based halide electrolyte in low-temperature battery

Abstract

The invention discloses preparation of a nitrogen-chlorine-based halide electrolyte and application of the nitrogen-chlorine-based halide electrolyte in a low-temperature battery, the chemical formula of the nitrogen-chlorine-based halide solid electrolyte is Li3xNx-MCly, x is greater than or equal to 0.1 and less than or equal to 1, y is greater than or equal to 1 and less than or equal to 5, and M is one of Y, In, Zr, Yb, Ta and Nb. The solid electrolyte is prepared by mixing metal nitride Li3N and metal chloride MCly according to the element stoichiometric ratio of a target chemical formula and carrying out high-energy ball milling reaction in an anhydrous and oxygen-free atmosphere, and the solid electrolyte is of an amorphous structure, has no resistance grain boundary and has excellent low-temperature ion transmission performance. And when the working voltage reaches 4.3 V, the interface of the electrolyte and the high-voltage positive electrode material can still keep good lithium ion transmission stability in an extremely low-temperature environment, can stably circulate for 50 times under the condition of-40 DEG C, can be used for assembling a low-temperature-resistant all-solid-state battery with high energy density and long cycle life, and has a wide commercial application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid-state batteries, and particularly relates to preparation of a nitrogen-chlorine-based halide electrolyte and application thereof in a low-temperature battery. BACKGROUND

[0002] With the development of new energy technology in the fields of polar exploration, high-altitude power stations, and transportation in low-temperature areas, stringent requirements are put forward for the working performance of lithium ion batteries under extremely low-temperature conditions. Traditional liquid lithium ion batteries use organic electrolyte, which will have problems such as significant increase in viscosity, sharp decrease in ionic conductivity, and increase in interfacial impedance under low-temperature conditions, resulting in a significant decrease in battery capacity and even failure to normally charge and discharge. In addition, the formation of lithium dendrites under low temperature will also bring serious safety hazards, greatly limiting the application of lithium ion batteries in low-temperature scenarios.

[0003] All-solid-state batteries use solid-state electrolyte to replace organic electrolyte, effectively solving the safety problem of liquid batteries, and the solid-state electrolyte has lower sensitivity to temperature fluctuations, providing the possibility for the development of low-temperature applicable batteries. Halide solid-state electrolyte has become one of the research hotspots in the field of solid-state electrolyte because of its high lithium ion conductivity and good interface compatibility. Among them, halide electrolyte has attracted widespread attention due to its low raw material cost and relatively simple synthesis process. However, the existing halide electrolyte is mostly polycrystalline structure, and the high activation energy at the grain boundary leads to blocked ion transport under low temperature, and there are problems such as poor interface stability under high pressure, which limits its application in high-energy-density all-solid-state batteries under extremely low temperature. Therefore, it is of great practical significance to develop a halide solid-state electrolyte with high lithium ion conductivity, excellent high-pressure stability and low-temperature resistance. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a nitrogen-chlorine-based composite halide solid-state electrolyte. Through the synergistic doping of nitrogen atoms and lithium ions, an amorphous structure electrolyte system is constructed to eliminate the grain boundary resistance and improve the low-temperature ion transport capacity and high-pressure stability.

[0005] In order to achieve the above technical purpose, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, the nitrogen-chlorine-based composite halide solid-state electrolyte provided by the present application has a chemical formula of Li 3x N x -MCl y , wherein 0.1≤x≤1, 1≤y≤5, and M is one of Y, In, Zr, Yb, Ta, and Nb.

[0007] Optionally, 0.1 < x < 1, 1 < y < 5, M is one of Y, In, Zr, Yb, Ta, Nb.

[0008] Optionally, the halide solid state electrolyte has a room temperature lithium ion conductivity > 0.1 mS / cm.

[0009] Optionally, the halide solid state electrolyte material is selected from Li 0.5 N 0.17 -YCl3, LiN 0.33 -YCl3, Li 1.5 N 0.5 -YCl3, Li2N 0.67 -YCl3, Li 2.5 N 0.83 -YCl3, Li3N -YCl3, Li 0.5 N 0.17 -InCl3, LiN 0.33 -InCl3, Li 1.5 N 0.5 -InCl3, Li2N 0.67 -InCl3, Li 2.5 N 0.83 -InCl3, Li3N -InCl3, Li 0.5 N 0.17 -ZrCl4, LiN 0.33 -ZrCl4, Li 1.5 N 0.5 -ZrCl4, Li2N 0.67 -ZrCl4, Li 2.5 N 0.83 -ZrCl4, Li3N -ZrCl4, Li 0.5 N 0.17 -YbCl3, LiN 0.33 -YbCl3, Li 1.5 N 0.5 -YbCl3, Li2N 0.67 -YbCl3, Li 2.5 N 0.83 -YbCl3, Li3N -YbCl3, Li 0.5 N 0.17 -TaCl5, LiN 0.33 -TaCl5, Li 1.5 N 0.5 -TaCl5, Li2N 0.67 -TaCl5, Li 2.5 N 0.83 -TaCl5, Li3N -TaCl5, Li 0.5 N 0.17-NbCl5, LiN 0.33 -NbCl5, Li 1.5 N 0.5 -NbCl5, Li2N 0.67 -NbCl5, Li 2.5 N 0.83 -NbCl5, Li3N-NbCl5one or more of.

[0010] The second aspect of the present application provides a preparation method of the above-mentioned nitrogen-chlorine-based composite halide solid-state electrolyte, comprising the following steps:

[0011] According to the chemical formula, the raw materials including Li3N, YCl3, InCl3, ZrCl4, YbCl3, TaCl5, NbCl5 are weighed in molar ratio;

[0012] The Li3N, YCl3, InCl3, ZrCl4, YbCl3, TaCl5, NbCl5 are ground into powder respectively and mixed to obtain a raw material mixture;

[0013] The raw material mixture is placed in a zirconia ball mill tank, argon or nitrogen is introduced into the ball mill tank to replace air, and the oxygen content and water content are ensured to be lower than 0.1 ppm; zirconia grinding balls are used, the mass ratio of ball to material is 15:1~50:1, the rotation speed of the ball mill is set to 400~800 rpm, the ball milling time is 5~60 h, and the ball milling process adopts an alternating forward and reverse rotation mode (such as forward rotation for 15 min, rest for 5 min, then reverse rotation for 15 min, rest for 5 min), and the amorphous structure of the nitrogen-chlorine-based composite halide solid-state electrolyte powder is obtained after ball milling;

[0014] The third aspect of the present application provides a nitrogen-chlorine-based composite halide solid-state electrolyte, which can be used as a lithium ion transmission medium in a low-temperature working condition solid-state battery:

[0015] The nitrogen-chlorine-based composite halide solid-state electrolyte is a halide solid-state electrolyte prepared by the preparation method described above;

[0016] The low-temperature working condition is -40℃~25℃.

[0017] The fourth aspect of the present application provides a full solid-state battery, which comprises oppositely arranged positive and negative electrode sheets, and a solid-state electrolyte arranged between the positive and negative electrode sheets, wherein the solid-state electrolyte comprises the solid-state electrolyte described above.

[0018] The advantages of the present application are:

[0019] The preparation of the nitrogen-chlorine-based halide electrolyte of the application effectively solves the problem of sharp drop of ion conductivity at low temperature of the traditional liquid electrolyte, and cannot charge and discharge, and also overcomes the defect of low-temperature ion transmission blockage of the existing zirconium-based halide electrolyte, and can meet the use requirements of polar exploration, high-altitude power station and other extremely low-temperature scenes. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the X-ray diffraction analysis spectrum of the nitrogen-chlorine-based composite halide solid-state electrolyte prepared in embodiment 1 of the application.

[0021] Figure 2 is the electrochemical impedance test curve of the nitrogen-chlorine-based composite halide solid-state electrolyte prepared in embodiment 1 of the application.

[0022] Figure 3 is the direct current polarization test curve of the nitrogen-chlorine-based composite halide solid-state electrolyte prepared in embodiment 1 of the application.

[0023] Figure 4 is the low-temperature cycle performance graph of the nitrogen-chlorine-based composite halide solid-state electrolyte prepared in embodiment 1 of the application for a full solid-state battery. DETAILED DESCRIPTION

[0024] In a first aspect, the embodiment of the application provides a nitrogen-chlorine-based composite halide solid-state electrolyte material, the chemical formula of the composite halide solid-state electrolyte material is Li 3x N x -MCl y , wherein 0.1≤x≤1, 1≤y≤5, and M is one of Y, In, Zr, Yb, Ta and Nb.

[0025] In the embodiment of the application, x is preferably 0.1≤x≤0.9, and 3≤y≤5.

[0026] In the embodiment of the application, the halide solid-state electrolyte material is selected from Li 0.5 N 0.17 -YCl3, LiN 0.33 -YCl3, Li 1.5 N 0.5 -YCl3, Li2N 0.67 -YCl3, Li 2.5 N 0.83 -YCl3, Li3N-YCl3, Li 0.5 N 0.17 -InCl3, LiN 0.33 -InCl3, Li 1.5 N 0.5 -InCl3, Li2N 0.67 -InCl3, Li2.5 N 0.83 -InCl3, Li3N-InCl3, Li 0.5 N 0.17 -ZrCl4, LiN 0.33 -ZrCl4, Li 1.5 N 0.5 -ZrCl4, Li2N 0.67 -ZrCl4, Li 2.5 N 0.83 -ZrCl4, Li3N-ZrCl4, Li 0.5 N 0.17 -YbCl3, LiN 0.33 -YbCl3, Li 1.5 N 0.5 -YbCl3, Li2N 0.67 -YbCl3, Li 2.5 N 0.83 -YbCl3, Li3N-YbCl3, Li 0.5 N 0.17 -TaCl5, LiN 0.33 -TaCl5, Li 1.5 N 0.5 -TaCl5, Li2N 0.67 -TaCl5, Li 2.5 N 0.83 -TaCl5, Li3N-TaCl5, Li 0.5 N 0.17 -NbCl5, LiN 0.33 -NbCl5, Li 1.5 N 0.5 -NbCl5, Li2N 0.67 -NbCl5, Li 2.5 N 0.83 -NbCl5, Li3N-NbCl5, one or more of the resulting lithium ion conductivity ≥ 0.1 mS / cm.

[0027] In a second aspect, the embodiments of the present application provide a preparation method of a nitrogen-chlorine-based composite halide solid-state electrolyte, comprising the following steps:

[0028] According to the chemical formula, the raw materials are taken in a molar ratio, and the raw materials include Li3N, YCl3, InCl3, ZrCl4, YbCl3, TaCl5, and NbCl5.

[0029] The Li3N and YCl3 or InCl3 or ZrCl4 or YbCl3 or TaCl5 or NbCl5 are ground into powder and mixed, respectively, to obtain a raw material mixture.

[0030] The weighed raw materials are placed in a zirconium oxide ball mill tank, and after ball milling, an amorphous structure of a nitrogen-chlorine-based composite halide solid-state electrolyte powder is obtained.

[0031] In the embodiments of the present application, argon or nitrogen is introduced into the ball mill tank to replace air, so as to ensure that the oxygen content and water content are lower than 0.1 ppm.

[0032] In the embodiments of the present application, zirconium oxide grinding balls are used, the ball-to-material mass ratio is 15:1 to 50:1, the ball mill speed is set to 400 to 800 rpm, the ball milling time is 5 to 60 h, and the ball milling process adopts an alternating forward and reverse rotation mode (for example, forward rotation for 15 min, rest for 5 min, reverse rotation for 15 min, and rest for 5 min).

[0033] In a third aspect, the nitrogen-chlorine-based composite halide solid-state electrolyte provided by the embodiments of the present application can be used as a lithium ion transmission medium in a low-temperature working condition solid-state battery, and the low-temperature working condition is -40℃ to 25℃.

[0034] In a fourth aspect, the embodiments of the present application provide a full solid-state battery, which comprises oppositely arranged positive and negative electrode sheets, and a solid-state electrolyte as described in any of the preceding embodiments, and the solid-state electrolyte film is arranged between the positive and negative electrode sheets.

[0035] The present application will be described more completely and in greater detail below with reference to the accompanying drawings and embodiments. The embodiments described below are part of the embodiments of the present application, and the scope of protection of the present application is not limited to the following embodiments.

[0036] Embodiment 1

[0037] Synthesis of the solid-state electrolyte: in an argon-filled glove box, 2 g of corresponding Li3N and ZrCl4 chemical raw materials are accurately weighed, wherein the raw material ratio is: the molar ratio of Li3N and ZrCl4 is 0.33:1. After grinding into powder, the raw material mixture is placed in a zirconium oxide ball mill tank, and after ball milling, an amorphous structure of a nitrogen-chlorine-based composite halide solid-state electrolyte powder is obtained. The obtained product is LiN 0.33 -ZrCl4 material.

[0038] The halide electrolyte synthesized above is tested: an X-ray diffractometer is used to analyze the X-ray diffraction of the electrolyte, and the results are shown in Figure 1 As can be seen from the figure, the XRD curve presents an amorphous state characteristic, and no impurity phase appears.

[0039] The synthesized nitrogen-chlorine complex halide solid electrolyte was pressed into tablets, assembled in a PEEK mold, and subjected to electrochemical impedance spectroscopy and DC polarization tests on an electrochemical workstation. The test frequency range was 1 Hz to 10 MHz. The electrochemical impedance spectroscopy curves are shown below. Figure 2 As shown in the figure, based on the thickness of the test piece, the lithium-ion conductivity of the material can be calculated to be 0.83 mS / cm; its DC polarization test curve is shown in the figure. Figure 3 As shown in the figure, the electronic conductivity of this material can be calculated to be 1.9 × 10⁻⁶. -8 The S / cm indicates that the above-mentioned nitrogen-chlorine composite halide solid electrolyte is a pure lithium-ion conductor.

[0040] All-solid-state batteries were assembled in an argon-filled vacuum glove box using the synthesized halide electrolyte described above. The positive electrode was a bare high-nickel ternary electrode, and the negative electrode was a LiIn alloy. Electrochemical performance was then tested, and the cycle performance is shown in the figure below. Figure 4 As shown, after 50 cycles at -40℃ and 0.05C, the capacity retention rate is still 98%, and the capacity release is 98 mAh / g, which overcomes the defect of low-temperature ion transport obstruction in existing zirconium-based halide electrolytes.

[0041] Example 2

[0042] This embodiment is basically the same as Embodiment 1, except that the molar ratio of Li3N to ZrCl4 in the synthesis of the solid electrolyte is changed to 0.17:1. All other parameters and steps remain unchanged.

[0043] Example 3

[0044] This embodiment is basically the same as Example 1, except that the molar ratio of Li3N to ZrCl4 is changed to 0.5:1 in the synthesis of the solid electrolyte. All other parameters and steps remain unchanged.

[0045] Example 4

[0046] This embodiment is basically the same as Embodiment 1, except that the molar ratio of Li3N to ZrCl4 in the synthesis of the solid electrolyte is changed to 0.67:1. All other parameters and steps remain unchanged.

[0047] Example 5

[0048] This embodiment is basically the same as Example 1, except that the molar ratio of Li3N to ZrCl4 in the synthesis of the solid electrolyte is changed to 0.83:1. All other parameters and steps remain unchanged.

[0049] Example 6

[0050] This example is basically the same as example 1, the only difference is that in the synthesis of the solid-state electrolyte of this example, the molar ratio of Li3N, ZrCl4 is changed to 1:1. Except for this, other parameters and steps are unchanged.

[0051] Comparative example 1

[0052] This comparative example is basically the same as example 1, the only difference is that in the synthesis of the solid-state electrolyte of this comparative example, the molar ratio of LiCl, ZrCl4 is changed to 0.5:1. Except for this, other parameters and steps are unchanged.

[0053] The comparison of the room temperature ionic conductivity of all examples and comparative examples is shown in Table 1.

[0054] Table 1: Chemical Formula Ionic conductivity (mS / cm) Example 1 Li 0.5 N 0.17 -ZrCl4]]> 0.14 Example 2 LiN 0.33 -ZrCl4]] 0.83 Example 3 Li 1.5 N 0.5 -ZrCl4]]> 0.21 Example 4 Li2N 0.67 ZrCl4 0.045 Example 5 , Li 2.5 N 0.83 -ZrCl4]]> 0.012 Example 6 Li3N-ZrCl4 0.006 Comparative Example 1 Li2ZrCl6 0.40

[0055] From the above test results, it can be seen that the ionic conductivity of the halide solid-state electrolyte prepared in the example of the present application is obviously improved compared with the halide solid-state electrolyte material of comparative example 1.

Claims

1. A nitrogen-chlorine-based composite halide solid electrolyte material, which can be used as a lithium-ion transport medium in low-temperature solid-state batteries, characterized in that, The chemical formula of the halide solid electrolyte material is Li 3x N x -MCl y , where 0.1≤x≤1, 1≤y≤5, and M is one of Y, In, Zr, Yb, Ta, and Nb.

2. The method for preparing the nitrogen-chlorine-based composite halide solid electrolyte according to claim 1, characterized in that, Includes the following steps: According to the elemental stoichiometry of the chemical formula in claim 1, weigh out the metal nitride Li3N and the metal chloride MCl. y After mixing in an anhydrous and oxygen-free atmosphere, the mixture is subjected to high-energy ball milling. After ball milling, the nitrogen-chlorine-based composite halide solid electrolyte is obtained.

3. This solid electrolyte has an amorphous structure and an ionic conductivity greater than 0.8 × 10⁻⁶ at room temperature. -3 S / cm, with an ionic conductivity of not less than 0.02×10 at -40℃. -3 S / cm, electrochemical stability window is 2.6~4.3V (relative to Li). + / Li electrode.

4. The halide solid electrolyte material according to any one of claims 1 to 3, characterized in that, The halide solid electrolyte material is selected from Li 0.5 N 0.17 -YCl3, LiN 0.33 -YCl3, Li 1.5 N 0.5 -YCl3, Li2N 0.67 -YCl3, Li 2.5 N 0.83 -YCl3, Li3N - YCl3, Li 0.5 N 0.17 -InCl3, LiN 0.33 -InCl3, Li 1.5 N 0.5 -InCl3, Li2N 0.67 -InCl3, Li 2.5 N 0.83 -InCl3, Li3N - InCl3, Li 0.5 N 0.17 -ZrCl4, LiN 0.33 -ZrCl4, Li 1.5 N 0.5 -ZrCl4, Li2N 0.67 -ZrCl4, Li 2.5 N 0.83 -ZrCl4, Li3N - ZrCl4, Li 0.5 N 0.17 -YbCl3, LiN 0.33 -YbCl3, Li 1.5 N 0.5 -YbCl3, Li2N 0.67 -YbCl3, Li 2.5 N 0.83 -YbCl3, Li3N - YbCl3, Li 0.5 N 0.17 -TaCl5, LiN 0.33 -TaCl5, Li 1.5 N 0.5 -TaCl5, Li2N 0.67 -TaCl5, Li 2.5 N 0.83 -TaCl5, Li3N - TaCl5, Li 0.5 N 0.17 -NbCl5, LiN 0.33 -NbCl5, Li 1.5 N 0.5 -NbCl5, Li2N 0.67 -NbCl5, Li 2.5 N 0.83 One or more of -NbCl5 and Li3N-NbCl5.

5. The preparation method according to claim 2, characterized in that: The ball milling conditions are a rotation speed of 400~800 rpm and a ball milling time of 5~60 h.

6. The preparation method according to claim 2, characterized in that: The anhydrous and oxygen-free atmosphere is an argon or nitrogen atmosphere, wherein the oxygen content is less than 0.01 ppm and the water content is less than 0.01 ppm.

7. The preparation method according to claim 2, characterized in that: The ball mill uses a zirconia ball mill jar and zirconia ball mill beads, with a ball-to-material mass ratio of 15:1 to 50:

1.

8. The application of the nitrogen-chlorine composite halide solid electrolyte of claim 1 as a lithium-ion transport medium in a low-temperature solid-state battery, wherein the low-temperature condition is -40℃ to 25℃.

9. An all-solid-state battery, characterized in that, It includes a positive electrode and a negative electrode arranged opposite to each other, and a solid electrolyte disposed between the positive electrode and the negative electrode, wherein the solid electrolyte includes the nitrogen-chlorine complex halide solid electrolyte of claim 1.

Images