Chloride solid-state electrolyte stable to lithium metal negative electrode and preparation method and application thereof

Abstract

This invention discloses a type of chloride solid electrolyte that stabilizes the lithium metal anode, its preparation method, and its application in solid-state lithium metal batteries. The chloride solid electrolyte of this invention, which stabilizes the lithium metal anode, has the chemical formula shown in formula (Ⅰ): ZrCl4· x Li3PO4· y M(SO4) n (I), where 0.2≤x≤1, 0.05≤y≤0.6; M is selected from Ca 2+ Mg 2+ Co 2+ Ni 2+ Mn 2+ Zn 2+ Cu 2+ Ba 2+ 、Sr 2+ Pb 2+ Fe 2+ Fe 3+ Al 3+ Zr 4+ K + Na + One, two, or more of the following. This invention prepares a chloride solid electrolyte that stabilizes the lithium metal anode by introducing sulfate, effectively improving the lithium-ion conductivity of the chloride solid electrolyte (≥ 2×10⁻⁶). ‑4 S cm ‑1 It also improves the thermodynamic stability potential of the electrolyte, enabling stable lithium ion transport at the high-voltage cathode / electrolyte interface at 4.5 V, making it more suitable for all-solid-state batteries with high capacity and high voltage operation of lithium metal anode.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, specifically relating to a type of chloride solid electrolyte that is stable to lithium metal anode, its preparation method and application. Background Technology

[0002] In recent years, with the rapid development of the large-scale energy storage equipment market, all-solid-state batteries have attracted much attention due to their advantages such as high safety and high energy density. Solid-state electrolytes are a crucial component in the development of all-solid-state batteries; they not only serve as the carrier for ion transport but also determine the battery's interface stability, cycle life, and overall electrochemical performance. An ideal solid-state electrolyte must simultaneously meet several requirements: First, it must possess high lithium-ion conductivity (typically exceeding 1 mS·cm at room temperature). -1 First, it must have a wide electrochemical stability window to ensure high power output of the battery. Second, it must have a certain mechanical properties to achieve close contact with the electrode material and suppress lithium dendrite growth.

[0003] For solid-state electrolytes, current research mainly focuses on the following types: polymer-based, oxide-based, sulfide-based, and halide-based lithium-ion conductive materials. Each material has its own advantages and disadvantages. Polymer-based solid-state electrolytes possess excellent mechanical properties but exhibit low ionic conductivity at room temperature and insufficient high-voltage withstand capability. Oxide-based solid-state electrolytes have high oxidation stability and good chemical stability, but their low ionic conductivity and high solid-solid interface impedance limit their commercialization progress. Sulfide-based solid-state electrolytes, while demonstrating excellent lithium-ion conductivity and flexibility, have a narrow electrochemical window, making them incompatible with high-voltage cathode materials and lithium metal anodes. In contrast, halide-based solid-state electrolytes (especially chlorides) exhibit unique comprehensive advantages, possessing both high ionic conductivity and high voltage stability with good flexibility. This combination of characteristics makes halide electrolytes a highly promising material platform for realizing high-energy-density, high-safety all-solid-state lithium metal batteries.

[0004] However, existing chloride solid electrolytes still face two major bottlenecks: first, their interfacial stability with lithium metal anodes is generally insufficient; second, their high-performance composition often relies on expensive and rare rare earth elements (such as Y, In, Ta, La, Sc, etc.), resulting in high material costs and poor resource sustainability. Therefore, developing a type of chloride solid electrolyte that combines high ionic conductivity, a wide electrochemical window, excellent mechanical properties, low cost, and long-term stable compatibility with lithium metal anodes has become a core issue that urgently needs to be addressed to advance the commercialization of all-solid-state batteries. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A type of chloride solid electrolyte that is stable to a lithium metal anode has the chemical formula shown in formula (Ⅰ): ZrCl4· x Li3PO4· y M(SO4) n (I) Where 0.2≤x≤1, 0.05≤y≤0.6; M is selected from Ca 2+ Mg 2+ Co 2+ Ni 2+ Mn 2+ Zn 2+ Cu 2+ Ba 2+ 、Sr 2+ Pb 2+ Fe 2+ Fe 3+ Al 3+ Zr 4+ K + Na + One, two, or more of the following.

[0006] Preferably, 0.3 ≤ x ≤ 0.6, for example, 0.3, 0.4, 0.5, 0.6 or any two of the above values.

[0007] Preferably, 0.1≤y≤0.25, for example, 0.1, 0.15, 0.2, 0.25 or any two of the above values.

[0008] According to an exemplary embodiment of the present invention, the chloride solid electrolyte that stabilizes the lithium metal anode is ZrCl4·0.4Li3PO4·0.1CaSO4.

[0009] According to an exemplary embodiment of the present invention, the chloride solid electrolyte that stabilizes the lithium metal anode is ZrCl4·0.4Li3PO4·0.2CaSO4.

[0010] According to an exemplary embodiment of the present invention, the chloride solid electrolyte that stabilizes the lithium metal anode is ZrCl4·0.5Li3PO4·0.2CaSO4.

[0011] According to an exemplary embodiment of the present invention, the chloride solid electrolyte that stabilizes the lithium metal anode is ZrCl4·0.6Li3PO4·0.1BaSO4.

[0012] According to an exemplary embodiment of the present invention, the chloride solid electrolyte that stabilizes the lithium metal anode is ZrCl4·0.5Li3PO4·0.1BaSO4.

[0013] According to an exemplary embodiment of the present invention, the chloride solid electrolyte that stabilizes the lithium metal anode is ZrCl4·0.3Li3PO4·0.1Zr(SO4)2.

[0014] According to an exemplary embodiment of the present invention, the chloride solid electrolyte that stabilizes the lithium metal anode is ZrCl4·0.5Li3PO4·0.1Zr(SO4)2.

[0015] According to an embodiment of the present invention, the ionic conductivity of the chloride solid electrolyte is greater than 2 × 10⁻⁶. -4 S cm -1 The electrochemical window of the chloride solid electrolyte is 0–5 V (relative to Li). + / Li electrode) inside.

[0016] The present invention also provides a method for preparing the above-mentioned chloride solid electrolyte that is stable for lithium metal anode. The preparation method includes the following steps: weighing metal chloride, lithium salt and sulfate respectively, mixing and ball milling to obtain the chloride solid electrolyte that is stable for lithium metal anode.

[0017] According to an embodiment of the present invention, the metal chloride is ZrCl4.

[0018] According to an embodiment of the present invention, the lithium salt is Li3PO4.

[0019] According to an embodiment of the present invention, the sulfate is selected from one, two or more of the following: CaSO4, MgSO4, CoSO4, NiSO4, MnSO4, ZnSO4, CuSO4, BaSO4, SrSO4, PbSO4, FeSO4, Fe2(SO4)3, Al2(SO4)3, Zr(SO4)2, K2SO4, Na2SO4, etc.

[0020] According to an embodiment of the present invention, the molar ratio of the metal chloride, lithium salt and sulfate is 1:x:y, where x and y have the meanings described above.

[0021] According to an embodiment of the invention, the grinding is ball milling. Preferably, the ball milling is performed in a ball mill known in the art.

[0022] According to an embodiment of the present invention, the ball milling conditions are as follows: the rotation speed is 300~1000 rpm, preferably 400~600 rpm; the time is 1~50 h, preferably 4~30 h.

[0023] According to an embodiment of the present invention, the preparation method is carried out in an inert gas atmosphere; for example, weighing, mixing, and ball milling are all carried out in an inert gas atmosphere. Preferably, the inert gas in the inert gas atmosphere is selected from gases known in the art, such as Ar. Further, the O2 content in the inert gas atmosphere is less than 0.1 ppm and the H2O content is less than 0.1 ppm.

[0024] The present invention also provides the application of the above-mentioned chloride solid electrolyte that stabilizes the lithium metal anode, preferably in the preparation of solid-state batteries.

[0025] The present invention also provides a composite cathode material, the composite cathode material comprising the above-mentioned chloride solid electrolyte that stabilizes the lithium metal anode, the cathode active material, and the conductive agent.

[0026] According to an embodiment of the present invention, the positive electrode active material is LiFePO4, LiCoO2, LiNiO2, LiMn2O4, or LiNi 0.5 Mn 1.5 O4, Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O4, Li 1.2 Ni 0.2 Mn 0.6 O4, LiNi 0.6 Co 0.2 Mn 0.2 O4, LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LiNi 0.9 Co 0.5 Mn 0.5 O4 and LiNi 0.92 Co 0.03 Mn 0.05 One, two, or more of the following: O2 (NCM92).

[0027] According to an embodiment of the present invention, the conductive agent is one or more of Super-P, superconducting carbon black, acetylene black and Ketjen black.

[0028] According to an embodiment of the present invention, each 100 parts by weight of the composite cathode material comprises: 60-90 parts by weight of positive electrode active material 10-40 parts by weight of chloride solid electrolyte that is stable for lithium metal anode. Conductive agent: 0-6 parts by weight.

[0029] Furthermore, the mass ratio of the positive electrode active material, the chloride solid electrolyte that stabilizes the lithium metal negative electrode, and the conductive agent is (60~90):(10~40):(0~6), preferably (70~80):(20~30):(0~2).

[0030] According to an exemplary embodiment of the present invention, the positive electrode active material in the composite positive electrode is LiNi. 0.92 Co 0.03 Mn 0.05 The chloride solid electrolyte that is stable for lithium metal anode is ZrCl4·0.3Li3PO4·0.1Zr(SO4)2, and the mass ratio of positive electrode active material to chloride solid electrolyte that is stable for lithium metal anode is 80:20.

[0031] The present invention also provides a method for preparing the above-mentioned composite cathode material, the method comprising: mixing the lithium metal anode-stabilizing chloride solid electrolyte, the cathode active material, and the conductive agent in a certain proportion, followed by grinding or ball milling. Preferably, the proportion refers to the mass ratio of the lithium metal anode-stabilizing chloride solid electrolyte, the cathode active material, and the conductive agent as described above.

[0032] Preferably, grinding or ball milling can be performed using methods known in the art.

[0033] The present invention also provides an energy storage element, the energy storage element comprising the above-mentioned chloride solid electrolyte and / or composite cathode material that are stable for lithium metal anodes.

[0034] Furthermore, the energy storage element is a solid-state battery.

[0035] The present invention also provides a solid-state battery, the solid-state battery comprising a positive electrode, a solid electrolyte, and a negative electrode; wherein, The solid electrolyte is selected from the above-mentioned chloride solid electrolyte that is stable for lithium metal anodes; The positive electrode is selected from the above-mentioned composite positive electrode material; The negative electrode is selected from one of the following: metallic Li, Li-In alloy, and Si.

[0036] The present invention also provides a method for preparing the above-mentioned solid-state battery, the method comprising: First, the solid electrolyte is pressed under pressure to form a solid electrolyte sheet. Then, the composite positive electrode material is placed on one side of the solid electrolyte sheet and pressed under pressure to form a positive electrode. The negative electrode material is placed on the other side of the solid electrolyte sheet and pressed under pressure to form a negative electrode. The solid battery is then assembled under pressure.

[0037] According to an embodiment of the present invention, the pressure pressing or pressure assembly in the present invention can be carried out using conditions known in the art, as long as the solid-state battery can be obtained.

[0038] According to an embodiment of the present invention, the solid-state battery is prepared under an inert gas atmosphere. Preferably, the inert gas atmosphere has the meaning described above.

[0039] Beneficial effects: This invention prepares a chloride solid electrolyte that is stable against a lithium metal anode by introducing sulfate. By adjusting the type and proportion of sulfate, the electrochemical stability window of the solid electrolyte can be increased, effectively improving the lithium-ion conductivity of the chloride solid electrolyte (≥ 2×10⁻⁶). -4 S cm -1 It also improves the thermodynamic stability potential of the electrolyte, enabling stable lithium ion transport at the high-voltage cathode / electrolyte interface at 4.5 V when matched with the high-voltage cathode, making it more suitable for all-solid-state batteries with high capacity and high voltage operation of lithium metal anode.

[0040] The raw materials used in this invention are inexpensive, the preparation method of the chloride solid electrolyte is simple, and it can be easily combined with existing battery production processes to achieve large-scale production, thus broadening the application prospects of this type of solid electrolyte. Attached Figure Description

[0041] Figure 1 The results of scanning electron microscopy and X-ray energy dispersive spectroscopy (SEM-EDS) analysis of the chloride solid electrolyte ZrCl4·0.4Li3PO4·0.1CaSO4, which is stable for lithium metal anodes, in Example 1 of this invention.

[0042] Figure 2 The X-ray diffraction (XRD) test results are shown for the chloride solid electrolyte ZrCl4·0.4Li3PO4·0.1CaSO4 that is stable at the lithium metal anode in Example 1 of this invention.

[0043] Figure 3 The results are obtained by electrochemical impedance spectroscopy (EIS) of ZrCl4·0.4Li3PO4·0.1CaSO4, a chloride solid electrolyte that is stable at the lithium metal anode, in Example 1 of this invention.

[0044] Figure 4 The results are as follows: The lithium metal symmetric battery assembled with ZrCl4·0.4Li3PO4·0.1CaSO4, a chloride solid electrolyte that stabilizes the lithium metal anode, is shown in Example 1 of this invention, under a current of 0.1 mA / cm.

[0045] Figure 5The first charge-discharge curve of the all-solid-state lithium metal battery with a stable lithium metal anode, consisting of a chloride solid electrolyte ZrCl4·0.4Li3PO4·0.1CaSO4, is shown at 4.5V in Example 1 of this invention.

[0046] Figure 6 The results of scanning electron microscopy and X-ray energy dispersive spectroscopy (SEM-EDS) analysis of the chloride solid electrolyte ZrCl4·0.5Li3PO4·0.1BaSO4, which is stable for lithium metal anodes, in Example 5 of this invention.

[0047] Figure 7 The X-ray energy dispersive spectroscopy (XRD) results are shown for the chloride solid electrolyte ZrCl4·0.5Li3PO4·0.1BaSO4, which is stable for lithium metal anodes, in Example 5 of this invention.

[0048] Figure 8 The electrochemical impedance spectroscopy (EIS) results are shown for ZrCl4·0.5Li3PO4·0.1BaSO4, a chloride solid electrolyte that stabilizes the lithium metal anode, in Example 5 of this invention.

[0049] Figure 9 The results are as follows: The lithium metal symmetric battery assembled with ZrCl4·0.5Li3PO4·0.1BaSO4, a chloride solid electrolyte that stabilizes the lithium metal anode, is shown in Example 5 of this invention, under a current of 0.1 mA / cm.

[0050] Figure 10 The results are for the lithium metal symmetric battery assembled with the chloride solid electrolyte ZrCl4·0.4Li2O·0.1CaSO4 in Comparative Example 1 at a current of 0.1 mA / cm.

[0051] Figure 11 The results are for the lithium metal symmetric battery assembled with the chloride solid electrolyte ZrCl4·0.4Li3PO4·0.01CaSO4 in Comparative Example 2, at a current of 0.1 mA / cm. Detailed Implementation

[0052] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0053] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0054] Example 1 Preparation and performance testing of ZrCl4·0.4Li3PO4·0.1CaSO4, a chloride solid electrolyte stable with lithium metal anode. I. Preparation of Chloride Solid Electrolytes Stabilized by Lithium Metal Anodes Accurately weigh ZrCl4, Li3PO4, and CaSO4 in the appropriate molar ratios into a ball mill jar in a glove box. Tighten the jar to ensure an inert argon atmosphere with O2 and H2O contents less than 0.1 ppm. Ball mill at 450 rpm for 15 h to obtain a solid electrolyte ZrCl4·0.4Li3PO4·0.1CaSO4 that is stable for the lithium metal anode.

[0055] II. Characterization of lithium metal anode stabilized chloride solid electrolyte The scanning electron microscope (SEM) image and X-ray energy dispersive spectroscopy (EDS) image of the lithium metal anode-stabilized chloride solid electrolyte prepared in this embodiment are shown below. Figure 1 As shown, Zr, Ca, O, P, S, and Cl elements are uniformly distributed within the particles. X-ray diffraction (XRD) is as follows... Figure 2 As shown. In summary, this embodiment successfully obtained a stable chloride solid electrolyte ZrCl4·0.4Li3PO4·0.1CaSO4 for lithium metal anodes.

[0056] III. Testing of Lithium-ion Conductivity The prepared electrolyte powder was placed in a 10 mm diameter polytetrafluoroethylene mold, and then an EIS test was performed after applying pressure of 450 MPa using a 10 mm diameter iron cylinder. The test results are as follows. Figure 3 As shown, the obtained ionic conductivity at room temperature is 5.7. 10 -4 S cm -1 .

[0057] IV. Electrochemical Performance Testing 1. Preparation of a composite cathode material for a lithium metal anode stabilized by a chloride solid electrolyte, ZrCl4·0.4Li3PO4·0.1CaSO4: The positive electrode material NCM92 and the lithium metal negative electrode stabilizing chloride solid electrolyte ZrCl4·0.4Li3PO4·0.1CaSO4 were weighed at a mass ratio of 80:20, mixed in an agate mortar, and ground for 30 min to ensure uniform mixing, thus obtaining the composite positive electrode material.

[0058] 2. Assemble solid-state batteries: Lithium metal symmetric battery: 100 mg of ZrCl4·0.4Li3PO4·0.1CaSO4 was added to a mold with a diameter of 10 mm and pressurized to 1 t. Subsequently, a lithium metal anode with a diameter of 10 mm was added to each side of the chloride electrolyte and pressurized to 0.5 t. The preparation process must be carried out in a glove box.

[0059] Lithium metal full cell: 100 mg of ZrCl4·0.4Li3PO4·0.1CaSO4 was added to a mold with a diameter of 10 mm and pressurized to 1 t. Then, 8 mg of composite positive electrode material was added to one side of the chloride electrolyte and pressurized to 3 t, followed by the addition of a lithium metal negative electrode to the other side and pressurized to 0.5 t. The preparation process must be carried out in a glove box.

[0060] 3. Solid-state battery testing: Lithium metal symmetric battery: Test temperature 25 ℃, test current 0.1 mA / cm. Test data as follows: Figure 4 As shown.

[0061] All-solid-state lithium metal battery: The test temperature was 25 ℃, and the voltage range for constant current charge-discharge testing was 3.0~4.5 V. The charge-discharge curve of the all-solid-state battery at a charge-discharge rate of 0.1 C is shown below. Figure 5 As shown. The battery's discharge specific capacity at a 0.1 C rate is 207.8 mAh g. -1 .

[0062] Example 2 Preparation and performance testing of ZrCl4·0.4Li3PO4·0.2CaSO4, a lithium metal anode-stabilized chloride solid electrolyte. I. Preparation of Chloride Solid Electrolytes Stabilized by Lithium Metal Anodes The preparation steps are basically the same as in Example 1, except that different molar mass ratios are used.

[0063] II. Testing of Lithium-ion Conductivity The test conditions were basically the same as in Example 1, and the obtained ionic conductivity at room temperature was 4.3. 10 -4 S cm -1 .

[0064] Example 3 Preparation and performance testing of ZrCl4·0.5Li3PO4·0.2CaSO4, a lithium metal anode-stabilized chloride solid electrolyte. I. Preparation of Chloride Solid Electrolytes Stabilized by Lithium Metal Anodes The preparation steps are basically the same as in Example 1, except that different molar mass ratios are used.

[0065] III. Testing of Lithium-ion Conductivity The test conditions are basically the same as in Example 1, such as... Figure 5 As shown, the obtained ionic conductivity at room temperature is 6.7. 10 -4 Scm -1 .

[0066] Example 4 Preparation and performance testing of ZrCl4·0.6Li3PO4·0.1BaSO4, a lithium metal anode-stabilized chloride solid electrolyte. I. Preparation of Chloride Solid Electrolytes Stabilized by Lithium Metal Anodes Accurately weigh ZrCl4, Li3PO4, and BaSO4 in the appropriate molar ratios into a ball mill jar in a glove box. Tighten the jar to ensure an inert argon atmosphere with O2 and H2O contents less than 0.1 ppm. Ball mill at 450 rpm for 12 h to obtain the solid electrolyte ZrCl4·0.6Li3PO4·0.1BaSO4.

[0067] II. Testing of Lithium-ion Conductivity The test conditions were basically the same as in Example 1, and the obtained ionic conductivity at room temperature was 1.3. 10 -3 S cm -1 .

[0068] Example 5 Preparation and performance testing of ZrCl4·0.5Li3PO4·0.1BaSO4, a lithium metal anode-stabilized chloride solid electrolyte. I. Preparation of Chloride Solid Electrolytes Stabilized by Lithium Metal Anodes The preparation steps are basically the same as in Example 4, except that different molar mass ratios are used.

[0069] II. Characterization of lithium metal anode stabilized chloride solid electrolyte The scanning electron microscope (SEM) image and X-ray energy dispersive spectroscopy (EDS) image of the lithium metal anode-stabilized chloride solid electrolyte prepared in this embodiment are shown below. Figure 6 As shown, Zr, Ba, O, P, S, and Cl elements are uniformly distributed within the particles. X-ray diffraction (XRD) is as follows... Figure 7 As shown. In summary, this embodiment successfully obtained a stable chloride solid electrolyte ZrCl4·0.5Li3PO4·0.1BaSO4 for lithium metal anodes.

[0070] III. Testing of Lithium-ion Conductivity The test conditions were basically the same as in Example 1, and the test results were as follows: Figure 8As shown, the obtained ionic conductivity at room temperature is 7.5. 10 -4 S cm -1 .

[0071] IV. Electrochemical Performance Testing 1. Assemble lithium metal symmetric batteries: 100 mg of ZrCl4·0.5Li3PO4·0.1BaSO4 was added to a 10 mm diameter mold and pressurized to 1 t. Subsequently, a 10 mm diameter lithium metal anode was added to each side of the chloride electrolyte and pressurized to 0.5 t. The preparation process must be carried out in a glove box.

[0072] 2. Testing of lithium metal symmetric batteries: The test temperature was 25 ℃, and the test current was 0.1 mA / cm. Test data are as follows: Figure 9 As shown.

[0073] Example 6 Preparation and performance testing of ZrCl4·0.3Li3PO4·0.1Zr(SO4)2, a lithium metal anode-stabilized chloride solid electrolyte. I. Preparation of Chloride Solid Electrolytes Stabilized by Lithium Metal Anodes Accurately weigh ZrCl4, Li3PO4, and Zr(SO4)2 in the appropriate molar ratio into a ball mill jar in a glove box. Tighten the ball mill jar to ensure an inert argon atmosphere with O2 and H2O contents both less than 0.1 ppm. Ball mill at 450 rpm for 25 h to obtain a stable solid electrolyte for lithium metal anode: ZrCl4·0.3Li3PO4·0.1Zr(SO4)2.

[0074] II. Testing of Lithium-ion Conductivity The test conditions were basically the same as in Example 1, and the test results were as follows: Figure 9 As shown, the obtained ionic conductivity at room temperature is 4.6. 10 -4 S cm -1 .

[0075] Example 7 Preparation and performance testing of ZrCl4·0.5Li3PO4·0.1Zr(SO4)2, a lithium metal anode-stabilized chloride solid electrolyte. I. Preparation of Chloride Solid Electrolytes Stabilized by Lithium Metal Anodes The preparation steps are basically the same as in Example 6, except that different molar mass ratios are used. II. Testing of Lithium-ion Conductivity The test conditions were basically the same as in Example 1, and the obtained ionic conductivity at room temperature was 1.5. 10 -3 S cm -1 .

[0076] Comparative Example 1 This comparative example refers to Example 1, except that Li3PO4 is replaced with the same molar amount of Li2O; the other conditions are the same as in Example 1, and the solid electrolyte ZrCl4·0.4Li2O·0.1CaSO4 is obtained.

[0077] II. Testing of Lithium-ion Conductivity The test conditions were basically the same as in Example 1, and an ionic conductivity of 1.2 was obtained at room temperature. 10 -4 S cm -1 .

[0078] III. Electrochemical Performance Testing 1. Assemble lithium metal symmetric batteries: 100 mg of ZrCl4·0.4Li2O·0.1CaSO4 was added to a 10 mm diameter mold and pressurized to 1 t. Subsequently, a 10 mm diameter lithium metal anode was added to each side of the chloride electrolyte and pressurized to 0.5 t. The preparation process must be carried out in a glove box.

[0079] 2. Testing of lithium metal symmetric batteries: The test temperature was 25 ℃, and the test current was 0.1 mA / cm. Test data are as follows: Figure 10 As shown.

[0080] Comparative Example 2 This comparative example is based on Example 1, except that the raw materials were prepared according to the molar ratio of ZrCl4·0.4Li3PO4·0.01CaSO4 for the solid electrolyte; the other conditions are the same as in Example 1.

[0081] II. Testing of Lithium-ion Conductivity The test conditions were basically the same as in Example 1, and the ionic conductivity at room temperature was obtained as 9. 10 -5 S cm -1 .

[0082] III. Electrochemical Performance Testing 1. Assemble lithium metal symmetric batteries: 100 mg of ZrCl4·0.4Li3PO4·0.01CaSO4 was added to a 10 mm diameter mold and pressurized to 1 t. Subsequently, a 10 mm diameter lithium metal anode was added to each side of the chloride electrolyte and pressurized to 0.5 t. The preparation process must be carried out in a glove box.

[0083] 2. Testing of lithium metal symmetric batteries: The test temperature was 25 ℃, and the test current was 0.1 mA / cm. Test data are as follows: Figure 11 As shown.

[0084] The exemplary embodiments of the present invention have been described above. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A type of chloride solid electrolyte that is stable to a lithium metal anode, characterized in that, Its chemical formula is shown in formula (Ⅰ): ZrCl4· x Li3PO4· y M(SO4) n (Ⅰ) Where 0.2≤x≤1, 0.05≤y≤0.6; M is selected from Ca 2+ Mg 2+ Co 2+ Ni 2+ Mn 2+ Zn 2+ Cu 2+ Ba 2+ 、Sr 2+ Pb 2+ Fe 2+ Fe 3+ Al 3+ Zr 4+ K + Na + One, two, or more of them.

2. The chloride solid electrolyte according to claim 1, characterized in that, The ionic conductivity of the chloride solid electrolyte is greater than 2 × 10⁻⁶. -4 S cm -1 The electrochemical window of the chloride solid electrolyte is within 0~5 V.

3. The method for preparing a chloride solid electrolyte that stabilizes a lithium metal anode as described in claim 1 or 2, characterized in that, The preparation method includes the following steps: weighing metal chloride, lithium salt and sulfate respectively, mixing and ball milling to obtain the chloride solid electrolyte that is stable for lithium metal anode.

4. The preparation method according to claim 3, characterized in that, The metal chloride is ZrCl4; The lithium salt is Li3PO4; The sulfate is selected from one, two or more of the following: CaSO4, MgSO4, CoSO4, NiSO4, MnSO4, ZnSO4, CuSO4, BaSO4, SrSO4, PbSO4, FeSO4, Fe2(SO4)3, Al2(SO4)3, Zr(SO4)2, K2SO4, and Na2SO4. The molar ratio of the metal chloride, lithium salt, and sulfate is 1:x:y; The preparation method is carried out in an inert gas atmosphere.

5. The application of the chloride solid electrolyte that stabilizes the lithium metal anode as described in claim 1 or 2 in the preparation of solid-state batteries.

6. A composite cathode material, characterized in that, The composite cathode material includes the chloride solid electrolyte, cathode active material, and conductive agent that stabilize the lithium metal anode as described in claim 1 or 2. Preferably, the positive electrode active material is LiFePO4, LiCoO2, LiNiO2, LiMn2O4, or LiNi 0.5 Mn 1.5 O4, Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O4, Li 1.2 Ni 0.2 Mn 0.6 O4, LiNi 0.6 Co 0.2 Mn 0.2 O4, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.9 Co 0.5 Mn 0.5 O4 and LiNi 0.92 Co 0.03 Mn 0.05 One, two, or more of O2 (NCM92); Preferably, the conductive agent is one or more of Super-P, superconducting carbon black, acetylene black, and Ketjen black; Preferably, each 100 parts by weight of the composite cathode material comprises: 60-90 parts by weight of positive electrode active material 10-40 parts by weight of chloride solid electrolyte that is stable for lithium metal anode. 0-6 parts by weight of conductive agent; Preferably, the mass ratio of the positive electrode active material, the chloride solid electrolyte that stabilizes the lithium metal negative electrode, and the conductive agent is (60~90):(10~40):(0~6).

7. The method for preparing the composite cathode material according to claim 6 or 7, characterized in that, The preparation method includes: mixing the chloride solid electrolyte that is stable for lithium metal anode, the positive electrode active material and the conductive agent in proportion and then grinding or ball milling them.

8. An energy storage element, the energy storage element comprising the chloride solid electrolyte and / or composite cathode material that is stable for lithium metal anodes as described in claim 1 or 2; Preferably, the energy storage element is a solid-state battery.

9. A solid-state battery, characterized in that, The solid-state battery includes a positive electrode, a solid electrolyte, and a negative electrode; wherein... The solid electrolyte is selected from the chloride solid electrolyte that is stable for lithium metal anode as described in claim 1 or 2. The positive electrode is selected from the composite positive electrode material according to claim 6 or 7; The negative electrode is selected from one of the following: metallic Li, Li-In alloy, and Si.

10. The method for preparing a solid-state battery according to claim 9, characterized in that, The method for preparing the solid-state battery includes: First, the solid electrolyte is pressed under pressure to form a solid electrolyte sheet. Then, the composite positive electrode material is placed on one side of the solid electrolyte sheet and pressed under pressure to form a positive electrode. The negative electrode material is placed on the other side of the solid electrolyte sheet and pressed under pressure to form a negative electrode. The solid battery is then assembled under pressure.

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