Integrated positive electrode and all-solid-state battery

Abstract

The invention belongs to the field of solid-state batteries, and particularly relates to an integrated positive electrode and an all-solid-state battery. The invention discloses an integrated positive electrode material. The integrated positive electrode material is obtained by ball-milling a halide positive electrode material subjected to heat treatment and TaCl5. The integrated positive electrode material inhibits generation of a space charge layer and promotes interface transmission of lithium ions on one hand, and prevents direct contact between sulfide electrolyte and the positive electrode on the other hand, so that the interface stability is improved. The invention also provides an all-solid-state battery which takes the integrated positive electrode material as a positive electrode layer of the battery. In addition, the negative electrode of the battery is treated by adopting ionic liquid of which anions are selected from bis (trifluoromethanesulfonyl) imine, and a single-ion conductive modification film is formed on the surface of a negative electrode material, so that the interface stability of a negative electrode layer and a solid electrolyte layer is improved; therefore, the interface resistance between the layers of the all-solid-state battery is reduced, and the cycle performance of the all-solid-state battery is improved.

Description

Technical Field

[0001] The present invention belongs to the field of solid-state batteries, and particularly relates to an integrated cathode and a all-solid-state battery. Background Art

[0002] With the increasing popularity of electric vehicles, in order to eliminate range anxiety, higher requirements are put forward for the energy density of power batteries. However, for liquid lithium-ion batteries, high energy density means low safety. In recent years, with the progress of solid-state battery technology, especially the successful development of high ionic conductivity solid electrolytes, it has become possible to solve the battery safety problem by using highly safe solid-state batteries instead of liquid batteries. However, the common solid electrolytes have a relatively narrow electrochemical window and are prone to interfacial reactions with the positive and negative electrodes. Although interface modification can solve the above problems to a certain extent, it often involves complex processes and high processing costs. In addition, since the material systems of the positive electrode and the solid electrolyte are generally different, their chemical potentials and ion mobilities are different, and a space charge layer is often formed, resulting in an increase in interfacial resistance. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an integrated cathode that can suppress the space charge layer problem between the positive electrode and the solid electrolyte.

[0004] Another purpose of the present invention is to provide a solid-state lithium battery.

[0005] In order to achieve the above purposes, the present invention is implemented by adopting the following technical solutions:

[0006] An integrated cathode material, which is formed by ball milling a halide cathode material after heat treatment with TaCl5;

[0007] The formula of the halide cathode material is Li 2-2y M 1+y Cl 4-x A x , where M is selected from at least one of Fe, Ni, Mn, Co, Mg, Zn, Cu, and A is selected from at least one of F, Br, I. In the formula, 0≤x≤0.5, 0≤y≤0.3;

[0008] The weight ratio of the halide cathode material to TaCl5 is 5-20:1;

[0009] The ball milling time is 2-20 hours, and the ball milling speed is 300-500 rpm.

[0010] The inventor found that the integrated cathode material obtained by the above treatment can have good interfacial stability and low interfacial resistance when assembled into an all-solid-state battery with a sulfide solid electrolyte layer.

[0011] More preferably, the preparation method of the halide cathode material is to mix and ball-mill Li halide and M halide, and then perform heat treatment to obtain it.

[0012] The heat treatment can be carried out with reference to the conventional techniques in the art, generally in a vacuum quartz tube. Preferably, the temperature of the heat treatment is 300 - 500 °C, and the time of the heat treatment is 2 - 20 hours. Through the heat treatment, the crystallinity and capacity of the halide cathode material can be improved.

[0013] The inventor also observed that during the above ball-milling process, part of the halide cathode material Li 2- 2y M 1+y Cl 4-x A x reacts with TaCl5, and a uniform Li 2-2y M 1+y Cl 4-x A x / TaCl5 lithium ion conductive layer is formed on the surface of the particles; and Li 2-2y M 1+y Cl 4-x A x and Li 2-2y M 1+y Cl 4-x A x and Li 2-2y M 1+y Cl 4-x A x / TaCl5 become integrated. Therefore, it is inferred that this amorphous lithium ion conductive layer improves the interfacial stability and low interfacial resistance.

[0014] Preferably, an amorphous lithium ion conductive layer is formed on the surface of the halide cathode material.

[0015] According to the comparison of the impedance spectra of the materials before and after the ball-milling treatment, the inventor speculates that the ionic conductivity of the amorphous lithium ion conductive layer is approximately ≥ 10 -3 S / cm.

[0016] More preferably, at least two elements are contained in M, one of which is selected from Fe, Ni, Mn, Co; and the other is selected from Mg, Zn, Cu.

[0017] More preferably, at least two elements are contained in M, one of which is Fe, and the other is selected from Mg, Zn, Cu.

[0018] An integrated cathode layer includes the integrated cathode material, a binder, and a conductive agent.

[0019] Preferably, the mass ratio of the integrated cathode material, binder, and conductive agent is 80-95:1-5:1-10.

[0020] The binder described in the present invention can refer to the prior art.

[0021] More specifically, the binder is selected from polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, polycarbonate, polyethylene oxide, or polybutene.

[0022] More preferably, the binder is selected from polytetrafluoroethylene.

[0023] The conductive agent described in the present invention can refer to the prior art. More preferably, the conductive agent is selected from at least one of graphene, fullerene, acetylene black, Super P, carbon nanotubes, and carbon nanofibers.

[0024] A all-solid-state battery includes a negative electrode layer, a solid electrolyte layer, and the integrated positive electrode layer.

[0025] Preferably, the thickness of the integrated positive electrode layer is 50-200 μm.

[0026] Preferably, the negative electrode layer includes a negative electrode material and a modification film coated on the surface of the negative electrode material; the modification film contains lithium nitride, lithium sulfide, and lithium fluoride at the same time.

[0027] The inventors found that the negative electrode layer with this modification film has single-ion conductivity, can achieve rapid lithium ion transmission, and inhibit the formation of lithium dendrites.

[0028] The preparation method of the negative electrode layer can be obtained by surface-treating the negative electrode material with an ionic liquid. The anion of the ionic liquid is selected from bis(trifluoromethanesulfonyl)imide; the cation of the ionic liquid can be a pyrrolidine cation or a pyridine cation.

[0029] Specifically, the pyrrole-based ionic liquid can be specifically selected from N-methyl-N-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt, N-methyl-N-ethylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt, etc.; the pyridine-based ionic liquid can be specifically selected from N-butylpyridinium bis(trifluoromethanesulfonyl)imide salt, N-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide salt, N-octylpyridinium bis(trifluoromethanesulfonyl)imide salt.

[0030] Preferably, the surface treatment is specifically to immerse the negative electrode material in the ionic liquid. Preferably, the temperature of the immersion is 20-80 °C. Preferably, the immersion time is 10-60 minutes.

[0031] According to electron microscopy observation, the thickness of the modification film is approximately 2-10 nm.

[0032] Preferably, the negative electrode material is selected from metallic lithium or lithium alloys.

[0033] More preferably, the lithium alloy is selected from any one of lithium-silicon alloy, lithium-tin alloy, lithium-silver alloy, lithium-carbon alloy, lithium-boron alloy, lithium-magnesium alloy or lithium-zinc alloy.

[0034] Preferably, the thickness of the negative electrode layer is 10-100 μm.

[0035] Preferably, the electrolyte of the solid electrolyte layer is selected from sulfide electrolytes.

[0036] Preferably, the sulfide electrolyte is selected from Li 10 GeP2S 12 , Li6PS5Cl, Li3PS4, Li7P3S 11 or their derivatives; the derivative of Li 10 GeP2S 12 is Li 10 Ge 1-a B a P2S 12 , where B is selected from at least one of Sn and Si, and 0 < a ≤ 0.5; the derivative of Li6PS5Cl is Li 6-b PS 5-b D 1+b , where D is selected from at least one of Cl, Br and I, and 0 ≤ b ≤ 0.7; the derivative of Li3PS4 is Li3P 1-c Sb c S4, where 0 < c ≤ 0.5; the derivative of Li7P3S 11 is Li7P 3- d Sb d S 11 , where 0 < d ≤ 1.

[0037] More preferably, the room temperature lithium ion conductivity of the electrolyte of the solid electrolyte layer is ≥ 10 -3 S / cm.

[0038] Preferably, the solid electrolyte layer is obtained by mixing an electrolyte with a binder, roll-pressing them, and then pressing the mixture onto the surface of the negative electrode layer.

[0039] The preparation method of the all-solid-state battery includes the following steps:

[0040] S1. Prepare the negative electrode layer;

[0041] S2. Prepare the electrolyte into a solid electrolyte membrane and press it onto the surface of the negative electrode layer to obtain the solid electrolyte layer;

[0042] S3. Prepare the integrated cathode material;

[0043] S4. Mix the integrated cathode material with a binder and a conductive agent, and press it onto the surface of the solid electrolyte layer to form an integrated cathode layer;

[0044] S5. Package to obtain the all-solid-state battery.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention discloses an integrated cathode material, which is formed by ball-milling a halide cathode material after heat treatment with TaCl5. On the one hand, this integrated cathode material inhibits the generation of the space charge layer and promotes the interfacial transport of lithium ions. On the other hand, it prevents the direct contact between the sulfide electrolyte and the cathode, improving the interfacial stability; as a result, the interfacial resistance between the integrated cathode layer and the solid electrolyte layer is significantly reduced. The present invention also provides an all-solid-state battery, using the above integrated cathode material as the cathode layer of the battery. In addition, the negative electrode of the battery is treated with an ionic liquid whose anion is bis(trifluoromethanesulfonyl)imide to form a single-ion conductive modification film on the surface of the negative electrode material, improving the interfacial stability between the negative electrode layer and the solid electrolyte layer and enhancing the cycling performance of the all-solid-state battery. Description of the Drawings

[0047] Figure 1 Transmission electron microscope photograph of the integrated cathode material prepared in Example 1;

[0048] Figure 2 Schematic structural diagram of the all-solid-state battery prepared in Example 1;

[0049] Figure 3 Charge-discharge curve of the all-solid-state battery prepared in Example 1;

[0050] Figure 4 Cycling life diagram of the all-solid-state battery prepared in Example 1;

[0051] Figure 5 Charge-discharge curve of the all-solid-state battery prepared in Comparative Example 1;

[0052] Figure 6 Cycling life diagram of the all-solid-state battery prepared in Comparative Example 1. Detailed Description of the Invention

[0053] The following further elaborates the present invention with specific examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. The test methods used in the following examples are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0054] Example 1

[0055] Preparation of integrated cathode material:

[0056] Using LiCl, LiBr, FeCl2 and MnCl2 as raw materials, mixing them according to the stoichiometric ratio, and obtaining Li 1.8 FeMn 0.1 Cl 3.9 Br 0.1 through ball milling and heat treatment, where the ball milling time is 10 hours, the rotation speed is 400 rpm, the heat treatment temperature is 400 °C, the heat treatment time is 6 hours, and the heat treatment conditions are: first vacuum-packaged in a quartz tube, and then the quartz tube is placed in an electric furnace for heat treatment. Then the obtained Li 1.8 FeMn 0.1 Cl 3.9 Br 0.1 is mixed with TaCl5 at a ratio of 10:1, and then ball milled to obtain the integrated cathode material, where the ball milling time is 20 hours and the rotation speed is 500 rpm. The transmission electron microscope photograph confirms that the surface of the Li 1.8 FeMn 0.1 Cl 3.9 Br 0.1 cathode particles contains an amorphous lithium ion conductive layer, as shown in Figure 1 .

[0057] Preparation of all-solid-state battery:

[0058] S1. Soak a lithium-silver alloy foil with a silver content of 20 wt% in N-methyl-N-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt for 20 minutes at a soaking temperature of 60 °C, and then roll it to obtain a modified negative electrode layer with a thickness of 50 μm. It can be seen from the electron microscope observation that a modification film is formed on the surface of the lithium-silver alloy foil. Through X-ray photoelectron spectroscopy analysis, the modification film contains lithium nitride, lithium sulfide and lithium fluoride at the same time.

[0059] S2. Mix Li7P3S 11 with polytetrafluoroethylene at a weight ratio of 100:2, shear disperse and roll it to obtain a sulfide electrolyte film with a thickness of 50 μm, and then roll the electrolyte film onto the surface of the modified negative electrode layer to obtain a solid electrolyte layer.

[0060] S3. Mix the above integrated cathode material, polytetrafluoroethylene and acetylene black in a weight ratio of 89:3:8, shear disperse and roll it to obtain an integrated cathode film with a thickness of 90 μm, and then roll the film onto the surface of the solid electrolyte layer to obtain an integrated cathode layer.

[0061] S4. Place aluminum foil and copper foil current collectors on the positive and negative sides of the above laminated material respectively, perform isostatic pressing treatment, and then encapsulate and assemble it into an all-solid-state battery. The structure of the battery is shown in Figure 2 .

[0062] The battery was charged and discharged at 2.5 - 4.1 V, 0.1 C (1 C is defined as 120 mA / g) at room temperature. The discharge capacity was 118.2 mAh / g, as shown in Figure 3 , and the capacity retention rate was 94.1% after 200 cycles at 1 C, as shown in Figure 4 . Through electrochemical impedance analysis, the interfacial impedance between the integrated positive electrode layer and the solid electrolyte layer was 6.2 Ω·cm 2 .

[0063] Example 2

[0064] Preparation of integrated positive electrode material:

[0065] Using LiCl, LiBr, MnCl2, FeCl2, and MgCl2 as raw materials, the materials were mixed according to the stoichiometric ratio, and after ball milling and heat treatment, Li 1.4 Fe 1.1 Mn 0.1 Mg 0.1 Cl 3.7 Br 0.3 was obtained, where the ball milling time was 10 hours, the rotation speed was 400 rpm, the heat treatment temperature was 400 °C, the heat treatment time was 6 hours, and the heat treatment conditions were: first vacuum encapsulated in a quartz tube, and then the quartz tube was placed in an electric furnace for heat treatment. Then the obtained Li 1.4 Fe 1.1 Mn 0.1 Mg 0.1 Cl 3.7 Br 0.3 was mixed with TaCl5 in a ratio of 5:1 and then ball milled to obtain the integrated positive electrode material, where the ball milling time was 20 hours and the rotation speed was 500 rpm. Transmission electron microscope photos confirmed that the surface of the Li 1.4 Fe 1.1 Mn 0.1 Mg 0.1 Cl 3.7 Br 0.3 positive electrode particles contained an amorphous lithium ion conductive layer.

[0066] Preparation of all-solid-state battery:

[0067] S1. The lithium-magnesium alloy foil with a magnesium content of 15 wt% was immersed in N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt for 20 minutes at a soaking temperature of 60 °C, and then roll-pressed to obtain a modified negative electrode layer with a thickness of 50 μm. Electron microscopy observation showed that a modification film was formed on the surface of the lithium-magnesium alloy foil. Through X-ray photoelectron spectroscopy analysis, the modification film contained lithium nitride, lithium sulfide, and lithium fluoride at the same time.

[0068] S2. Li 5.5 PS4.5 ClBr 0.5 Mix with polytetrafluoroethylene in a weight ratio of 100:2, subject to shear dispersion and rolling, to obtain a sulfide electrolyte membrane with a thickness of 60 microns, and then roll the electrolyte membrane onto the surface of the modified negative electrode layer to obtain a solid electrolyte layer.

[0069] S3. Mix the above integrated cathode material, polytetrafluoroethylene, and acetylene black in a weight ratio of 90:4:6, subject to shear dispersion and rolling, to obtain an integrated cathode membrane with a thickness of 100 microns, and then roll this membrane onto the surface of the solid electrolyte layer to obtain an integrated cathode layer.

[0070] S4. Place aluminum foil and copper foil current collectors on the positive and negative sides of the above laminated material respectively, perform isostatic pressing treatment, and then encapsulate and assemble into a all-solid-state battery.

[0071] Charge and discharge the battery at 2.5 - 4.1V, 0.1C (1C is defined as 120 mA / g), and room temperature. The discharge capacity is 126.4 mAh / g, and the capacity retention rate is 93.3% after 200 cycles at 1C. Through electrochemical impedance analysis, the interfacial impedance between the integrated cathode layer and the solid electrolyte layer is 6.8 Ω·cm. 2 。

[0072] Example 3

[0073] Preparation of integrated cathode material:

[0074] Using LiCl, LiI, FeCl2, and MgCl2 as raw materials, mix them according to the stoichiometric ratio, and obtain Li2Fe 0.95 Mg 0.05 Cl 3.95 I 0.05 through ball milling and heat treatment, where the ball milling time is 10 hours, the rotation speed is 400 rpm, the heat treatment temperature is 400 °C, the heat treatment time is 6 hours, and the heat treatment conditions are: first vacuum package in a quartz tube, and then place the quartz tube in an electric furnace for heat treatment. Then mix the obtained Li2Fe 0.95 Mg 0.05 Cl 3.95 I 0.05 with TaCl5 in a ratio of 20:1, and then obtain the integrated cathode material through ball milling. The ball milling time is 20 hours, the rotation speed is 500 rpm. Transmission electron microscope photos confirm that the surface of the Li2Fe 0.95 Mg 0.05 Cl 3.95 I 0.05 cathode particles contains an amorphous lithium ion conductive layer.

[0075] Preparation of all-solid-state battery:

[0076] S1. Immerse a lithium-zinc alloy foil with a zinc content of 10 wt% in N-methyl-N-ethylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt for 20 minutes at a soaking temperature of 60 °C. After rolling, a modified negative electrode layer with a thickness of 60 microns is obtained. Electron microscopy observation shows that a modification film is formed on the surface of the lithium-zinc alloy foil. According to X-ray photoelectron spectroscopy analysis, the modification film contains lithium nitride, lithium sulfide, and lithium fluoride simultaneously.

[0077] S2. Mix Li3P 0.9 Sb 0.1 S4 and polytetrafluoroethylene in a weight ratio of 100:2, and after shear dispersion and rolling, a sulfide electrolyte film with a thickness of 55 microns is obtained. Then roll the electrolyte film onto the surface of the modified negative electrode layer to obtain a solid electrolyte layer.

[0078] S3. Mix the above integrated positive electrode material, polytetrafluoroethylene, and acetylene black in a weight ratio of 92:2:6, and after shear dispersion and rolling, an integrated positive electrode film with a thickness of 80 microns is obtained. Then roll this film onto the surface of the solid electrolyte layer to obtain an integrated positive electrode layer.

[0079] S4. Place aluminum foil and copper foil current collectors on the positive and negative sides of the above laminated material respectively, and after isostatic pressing treatment, package and assemble them into an all-solid-state battery.

[0080] Charge and discharge the battery at 2.5 - 4.1 V, 0.1 C (1 C is defined as 120 mA / g) at room temperature. The discharge capacity is 115.3 mAh / g, and the capacity retention rate after 200 cycles at 1 C is 92.9%. According to electrochemical impedance analysis, the interfacial impedance between the integrated positive electrode layer and the solid electrolyte layer is 7.1 Ω·cm 2 .

[0081] Example 4

[0082] Preparation of integrated positive electrode material:

[0083] Using LiCl, LiBr, FeCl2, and CuCl2 as raw materials, mix them according to the stoichiometric ratio, and obtain Li 1.6 Fe 1.15 Cu 0.05 Cl 3.5 Br 0.5 through ball milling and heat treatment, where the ball milling time is 10 hours, the rotation speed is 400 rpm, the heat treatment temperature is 400 °C, the heat treatment time is 6 hours, and the heat treatment conditions are: first vacuum package in a quartz tube, and then place the quartz tube in an electric furnace for heat treatment. Then the obtained Li 1.6 Fe 1.15 Cu 0.05 Cl 3.5 Br 0.5Mix with TaCl5 at a ratio of 10:1, and then obtain the integrated cathode material through ball milling. The ball milling time is 20 hours, and the rotation speed is 500 rpm. Transmission electron microscope photos confirm that Li 1.6 Fe 1.15 Cu 0.05 Cl 3.5 Br 0.5 The surface of the cathode particles contains an amorphous lithium-ion conductive layer.

[0084] Preparation of all-solid-state battery:

[0085] S1. Immerse the lithium-tin alloy foil with a tin content of 30 wt% in N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt for 20 minutes at a soaking temperature of 60 °C. After rolling, a modified negative electrode layer with a thickness of 65 μm is obtained. Electron microscopy observation shows that a modification film is formed on the surface of the lithium-tin alloy foil. Through X-ray photoelectron spectroscopy analysis, the modification film contains lithium nitride, lithium sulfide, and lithium fluoride at the same time.

[0086] S2. Mix Li 5.5 PS 4.5 Cl 1.5 with polytetrafluoroethylene at a weight ratio of 100:2, and through shear dispersion and rolling, a sulfide electrolyte membrane with a thickness of 65 μm is obtained. Then roll the electrolyte membrane onto the surface of the modified negative electrode layer to obtain a solid electrolyte layer.

[0087] S3. Mix the above integrated cathode material, polytetrafluoroethylene, and acetylene black at a weight ratio of 92:3:5, and through shear dispersion and rolling, an integrated cathode membrane with a thickness of 110 μm is obtained. Then roll this membrane onto the surface of the solid electrolyte layer to obtain an integrated cathode layer.

[0088] S4. Place aluminum foil and copper foil current collectors on the positive and negative sides of the above laminated material respectively. After isostatic pressing treatment, it is assembled into an all-solid-state battery through encapsulation.

[0089] Charge and discharge the battery at 2.4 - 4.0 V, 0.1 C (1 C is defined as 120 mA / g) at room temperature. The discharge capacity is 113.8 mAh / g, and the capacity retention rate after 200 cycles at 1 C is 92.1%. Through electrochemical impedance analysis, the interfacial impedance between the integrated cathode layer and the solid electrolyte layer is 7.3 Ωcm 2 .

[0090] Comparative Example 1

[0091] The production process of the all-solid-state battery is the same as that in Example 1, except that Li 1.8 FeMn 0.1 Cl 3.9 Br 0.1The positive electrode, rather than the integrated positive electrode, i.e., without adding TaCl5, has a discharge capacity of 100.3 mAh / g at 0.1C, as shown in Figure 5 , and the capacity retention rate is 81.1% after 100 cycles at 1C, as shown in Figure 6 . Through electrochemical impedance analysis, the interfacial impedance between the integrated positive electrode layer and the solid electrolyte layer is 230.1 Ωcm.

[0092] Comparative Example 2

[0093] The manufacturing process of the all-solid-state battery is the same as that of Example 1, except that TaCl5 is replaced with an equimolar amount of NbCl5. The discharge capacity is 97.4 mAh / g at 0.1C, and the capacity retention rate is 80.7% after 200 cycles at 1C. Through electrochemical impedance analysis, the interfacial impedance between the integrated positive electrode layer and the solid electrolyte layer is 160.9 Ωcm 2 .

[0094] Comparative Example 3

[0095] The manufacturing process of the all-solid-state battery is the same as that of Example 1, except that TaCl5 is replaced with an equimolar amount of Ta2O5. The discharge capacity is 91.5 mAh / g at 0.1C, and the capacity retention rate is 79.3% after 200 cycles at 1C. Through electrochemical impedance analysis, the interfacial impedance between the integrated positive electrode layer and the solid electrolyte layer is 211.4 Ωcm 2 .

[0096] Comparative Example 4

[0097] The manufacturing process of the all-solid-state battery is the same as that of Example 1, except that the positive electrode material is Li 1.8 FeMn 0.1 Cl 3.3 Br 0.7 . The discharge capacity is 101.6 mAh / g at 0.1C, and the capacity retention rate is 82.7% after 200 cycles at 1C. Through electrochemical impedance analysis, the interfacial impedance between the integrated positive electrode layer and the solid electrolyte layer is 31.2 Ωcm 2 .

[0098] Comparative Example 5

[0099] The manufacturing process of the all-solid-state battery is the same as that of Example 1, except that the positive electrode material is Li 1.2 FeMn 0.4 Cl 3.9 Br 0.1 . The discharge capacity is 102.2 mAh / g at 0.1C, and the capacity retention rate is 78.3% after 200 cycles at 1C. Through electrochemical impedance analysis, the interfacial impedance between the integrated positive electrode layer and the solid electrolyte layer is 44.3 Ωcm 2 .

[0100] Comparative Example 6

[0101] The manufacturing process of the all-solid-state battery was the same as that of Example 1, except that the cathode material was Li 1.2 Fe 1.3 Mn 0.1 Cl 3.9 Br 0.1 The discharge capacity at 0.1C was 106.2 mAh / g, and the capacity retention rate after 200 cycles at 1C was 82.0%. Through electrochemical impedance analysis, the interfacial impedance between the integrated cathode layer and the solid electrolyte layer was 28.6 Ω·cm 2 .

[0102] Comparative Example 7

[0103] The manufacturing process of the all-solid-state battery was the same as that of Example 1, except that the anode was not modified, that is, the lithium-silver alloy foil was not soaked in the ionic liquid. The discharge capacity at 0.1C was 112.5 mAh / g, and the capacity retention rate after 200 cycles at 1C was 83.1%.

[0104] Comparative Example 8

[0105] The manufacturing process of the all-solid-state battery was the same as that of Example 1, except that an equal amount of N-methyl-N-butylpyrrolidinium tetrafluoroborate was used to replace N-methyl-N-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt for the surface treatment of the anode layer. It can be seen from electron microscopy observation that a modification film was formed on the surface of the lithium-silver alloy foil. Through X-ray photoelectron spectroscopy analysis, the modification film only contained lithium fluoride. The measured discharge capacity at 0.1C was 114.1 mAh / g, and the capacity retention rate after 200 cycles at 1C was 85.2%.

[0106] Comparative Example 9

[0107] The manufacturing process of the all-solid-state battery was the same as that of Example 1, except that the surface treatment of the anode layer was carried out with reference to the prior art, as described in CN113258130A. Through X-ray photoelectron spectroscopy analysis, a lithium nitride film was formed on the anode layer. The discharge capacity at 0.1C was 113.7 mAh / g, and the capacity retention rate after 200 cycles at 1C was 84.1%.

[0108] Examples 5-6 and Comparative Examples 10-11

[0109] It was consistent with the formulation of the integrated cathode and all-solid-state battery of Example 1, except that the rotation speed and time of ball milling were adjusted when ball milling Li 1.8 FeMn 0.1 Cl 3.9 Br 0.1 with TaCl5, and the performance of the all-solid-state battery assembled therefrom is shown in Table 1.

[0110] Table 1

[0111]

[0112]

[0113] It can be seen from the comparison between the examples and the comparative examples that for the integrated cathode material prepared by the method of the present invention, when assembled into an all-solid-state battery, the interfacial resistance between the cathode layer and the solid electrolyte layer can be significantly reduced. The all-solid-state battery formed by the modified anode layer of the present invention in combination with the integrated cathode and the solid electrolyte layer has higher discharge capacity and cycling performance.

[0114] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. An integrated cathode material, characterized in that, The integrated cathode material is formed by ball-milling a halide cathode material after heat treatment with TaCl5; The molecular formula of the halide cathode material is Li 2-2y M 1+y Cl 4-x A x , where M is selected from at least one of Fe, Ni, Mn, Co, Mg, Zn, and Cu, and A is selected from at least one of F, Br, and I. In the formula, 0 ≤ x ≤ 0.5 and 0 ≤ y ≤ 0.3; The weight ratio of the halide cathode material to TaCl5 is 5-20:1; The ball-milling time is 2-20 hours, and the ball-milling rotation speed is 300-500 rpm.

2. The integrated cathode material according to claim 1, wherein An amorphous lithium-ion conductive layer is formed on the surface of the halide cathode material.

3. An integrated positive electrode layer, characterized in that, It includes the integrated cathode material according to claim 1 or 2, a binder, and a conductive agent.

4. The integrated positive electrode layer according to claim 3, wherein, The mass ratio of the integrated cathode material, the binder, and the conductive agent is 80-95:1-5:1-10.

5. A all-solid-state battery, characterized in that, It includes a negative electrode layer, a solid electrolyte layer, and the integrated cathode layer according to claim 3 or 4.

6. The all-solid-state battery according to claim 5, characterized in that, The thickness of the integrated cathode layer is 50-200 μm.

7. The all-solid-state battery according to claim 5, wherein The negative electrode layer includes a negative electrode material and a modification film coated on the surface of the negative electrode material; the modification film contains lithium nitride, lithium sulfide, and lithium fluoride at the same time.

8. The all-solid-state battery according to claim 7, wherein The negative electrode layer is obtained by surface-treating the negative electrode material with an ionic liquid; the anion of the ionic liquid is selected from bis(trifluoromethanesulfonyl)imide.

9. The all-solid-state battery according to claim 5, wherein The solid electrolyte in the solid electrolyte layer is selected from Li 10 GeP2S 12 , Li6PS5Cl, Li3PS4, Li7P3S 11 or their derivatives.

10. The all-solid-state battery according to claim 6, wherein, The electrolyte of the solid electrolyte layer is selected from sulfide electrolytes.

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