Preparation method and application of composite positive electrode containing halide electrolyte

Abstract

The invention discloses a preparation method and application of a composite positive electrode containing a halide electrolyte, belongs to the technical field of all-solid-state lithium ion battery positive electrode materials, and particularly relates to a core-shell type modified halide electrolyte obtained by mixing a halide electrolyte and an organic ligand and carrying out ball milling treatment. Carrying out ball milling treatment on the core-shell type modified halide electrolyte, NCM83125 and conductive carbon to obtain composite positive electrode powder; and grinding, mixing and rolling the composite positive electrode powder and a binder to obtain the composite positive electrode. According to the core-shell type modified halide electrolyte provided by the invention, the inner core is a halide electrolyte material, the outer layer is a coordination organic matter shell, and the dispersion of the modified halide electrolyte in a composite positive electrode can be effectively promoted based on the steric hindrance effect of the organic matter shell; and a good lithium ion conduction network is constructed while the proportion of the positive active material is increased, so that the overall energy density of the battery is improved, the positive reaction kinetics is improved, and the capacity and rate capability of the battery are improved.

Description

Technical Field

[0001] This invention belongs to the field of all-solid-state lithium-ion battery cathode material technology, specifically relating to a method for preparing a composite cathode containing a halide electrolyte and its application. Background Technology

[0002] With the widespread use of portable electronic devices and the rapid development of the electric vehicle industry, the demand for high-performance energy storage devices in modern society continues to rise. Traditional liquid lithium-ion batteries, limited by the theoretical capacity bottleneck of electrode materials, are struggling to meet the stringent requirements of next-generation electronic devices for high-energy-density energy storage systems. More importantly, as the scale of battery energy storage continues to expand, safety issues are becoming increasingly prominent—the safety hazards of leakage, flammability, and explosion inherent in traditional liquid electrolytes cannot be ignored. Against this backdrop, developing a new energy storage system that combines high energy density and excellent safety has become an urgent priority, making all-solid-state lithium-ion batteries a current research hotspot in the energy storage field.

[0003] Solid-state electrolytes are the most critical component of all-solid-state lithium batteries, and their performance directly determines the overall performance of the battery. In recent years, halide solid-state electrolytes have attracted much attention due to their excellent room-temperature ionic conductivity and wide electrochemical window. Compared with sulfide and oxide solid-state electrolytes, the monovalent halide ions in halide electrolytes have larger ionic radii, weaker lithium-ion interactions, and higher redox potentials. This makes halide electrolytes the most advanced cathode electrolyte filler in current all-solid-state lithium-ion batteries, exhibiting superior lithium-ion mobility, processability, and electrochemical stability.

[0004] Although halide electrolytes have been widely used in all-solid-state lithium batteries, composite cathodes based on halide electrolytes still face capacity limitations. Due to the large particle size of halide electrolytes, composite cathodes typically require up to 30% by mass of halide electrolyte, which limits the utilization rate of active materials. High-energy ball milling is a common method to reduce electrolyte particle size and construct a permeable ion conduction network. However, the mechanical crushing process leads to severe degradation of the halide electrolyte crystal structure and the generation of high surface energy. This metastable state induces a strong thermodynamic agglomeration tendency, thus affecting the dispersion uniformity of halide electrolyte particles in the composite cathode. Furthermore, the grain boundaries present in crystalline halide electrolytes hinder the achievement of high relative density during plastic deformation, thereby affecting the interfacial contact between the halide electrolyte and the active material, leading to interfacial contact failure. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a composite cathode containing a halide electrolyte that can be used to prepare all-solid-state lithium-ion batteries, and which has good safety performance, high energy density, low impedance, high discharge capacity and good long-cycle stability after being made into lithium-ion batteries.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows: A method for preparing a core-shell modified halide electrolyte includes: mixing a halide electrolyte and an organic ligand, followed by ball milling to obtain the core-shell modified halide electrolyte; the mass ratio of the halide electrolyte to the organic ligand is 1:0.003-0.05. The core-shell modified halide electrolyte is an organically coordinated modified halide electrolyte with a core-shell structure, containing a core halide electrolyte material and an outer organic shell. This core-shell modified halide electrolyte can be used to prepare composite cathodes. The core-shell structure of the core-shell modified halide electrolyte has a good promoting effect on its dispersibility in composite cathodes. Compared with unmodified halide electrolytes, the organic ligands on the surface of this core-shell structure inhibit the agglomeration tendency of the halide electrolyte during dispersion. Combined with dry hot rolling, it further promotes particle rearrangement, reduces the porosity in the composite cathode, constructs a more efficient lithium-ion transport network, and improves the electrolyte utilization efficiency and battery energy density in the composite cathode.

[0007] Preferably, in the ball milling process, the ball milling is performed at a speed of 50-300 rpm for 0.5-5 hours.

[0008] Preferably, the halide electrolyte is a crystalline halide electrolyte.

[0009] Preferably, the halide electrolyte is at least one of Li3InCl6, Li3YCl6 and Li2ZrCl6; or, the organic ligand is at least one of o-TCBQ, p-TCBQ, o-TFBQ and p-TFBQ.

[0010] Preferably, the ball milling process is carried out in an inert gas atmosphere. The inert gas is argon.

[0011] Preferably, the core-shell modified halide electrolyte is an electrolyte with an amorphous surface encapsulating an internal crystalline state, and has a particle size of 0.1~60μm.

[0012] Preferably, in the preparation of the core-shell modified halide electrolyte, the halide electrolyte and organic ligand are mixed and ball-milled at a speed of 50-300 rpm for 0.5-5 h to obtain the core-shell modified halide electrolyte.

[0013] More preferably, in the preparation of the core-shell modified halide electrolyte, the halide electrolyte is at least one of Li3InCl6, Li3YCl6 and Li2ZrCl6.

[0014] More preferably, in the preparation of the core-shell modified halide electrolyte, the organic ligand is at least one of o-TCBQ, p-TCBQ, o-TFBQ, and p-TFBQ.

[0015] More preferably, in the preparation of the core-shell modified halide electrolyte, the mass ratio of the amount of halide electrolyte to organic ligand is 1:0.003-0.05.

[0016] More preferably, in the preparation of the core-shell modified halide electrolyte, the organic ligands further include o-TCBQ and 2-amino-3-(3-indole)propionic acid, with a mass ratio of o-TCBQ to 2-amino-3-(3-indole)propionic acid of 1:0.1-1. After the halide electrolyte is modified by coordination of o-TCBQ and 2-amino-3-(3-indole)propionic acid, the amorphization of the spherical shell eliminates the grain boundaries on the electrolyte surface, increases the contact area between the electrolyte and the positive electrode active material, and ensures the cycle stability of the composite positive electrode due to good mechanical compatibility. The uniform and efficient lithium-ion transport channels constructed by the halide electrolyte modified by coordination of o-TCBQ and 2-amino-3-(3-indole)propionic acid lead to a uniform volume change in the composite positive electrode, thereby generating a self-compacting effect and further improving the cycle stability of the all-solid-state lithium-ion battery prepared from the composite positive electrode.

[0017] More preferably, in the preparation of the core-shell modified halide electrolyte, the organic ligand further includes o-TCBQ, 2-amino-3-(3-indolyl)propionic acid, and cyanuric acid, with a mass ratio of o-TCBQ, 2-amino-3-(3-indolyl)propionic acid, and cyanuric acid of 1:0.1-1:0.05-0.5. In this invention, after using o-TCBQ and 2-amino-3-(3-indolyl)propionic acid, cyanuric acid can be further added to form a spherical shell composed of o-TCBQ, 2-amino-3-(3-indolyl)propionic acid, and cyanuric acid. This further improves the performance of the composite cathode and enhances the cycle stability of the all-solid-state lithium-ion battery prepared from the composite cathode.

[0018] This invention discloses a core-shell modified halide electrolyte obtained by the above preparation method.

[0019] This invention discloses a method for preparing a composite positive electrode containing a halide electrolyte, comprising: the above-mentioned method for preparing a core-shell modified halide electrolyte.

[0020] Preferably, a composite cathode powder is obtained by ball milling a core-shell modified halide electrolyte, NCM83125, and conductive carbon; the composite cathode powder is then ground, mixed with a binder, and rolled to obtain a composite cathode.

[0021] More preferably, the conductive carbon is at least one of Super P, acetylene black, Ketjen black, carbon nanofibers, carbon nanotubes, graphene, and graphene oxide.

[0022] More preferably, the mass ratio of the core-shell modified halide electrolyte, NCM83125 and conductive carbon used is 2-12:20-30:1.

[0023] Preferably, in the preparation of the composite cathode powder, a core-shell modified halide electrolyte, NCM83125 and conductive carbon are mixed and ball-milled at a speed of 50-300 rpm for 0.5-5 h to obtain the composite cathode powder.

[0024] More preferably, in the preparation of the composite cathode powder, the conductive carbon is at least one of Super P, carbon nanotubes, and carbon nanofibers.

[0025] More preferably, in the preparation of the composite cathode powder, the mass ratio of the amount of core-shell modified halide electrolyte, NCM83125 and conductive carbon used is 2-12:20-30:1.

[0026] Preferably, in the preparation of the composite positive electrode, the composite positive electrode powder is ground and mixed with PTFE binder and rolled for 0.2-3 hours to obtain the composite positive electrode.

[0027] More preferably, in the preparation of the composite cathode, the mass ratio of the amount of PTFE binder to the amount of composite cathode powder is 1:0.005-0.02.

[0028] More preferably, in the preparation of the composite cathode, the grinding and mixing process involves ball milling at a speed of 50-300 rpm for 0.5-5 hours.

[0029] More preferably, in the preparation of the composite cathode, the thickness of the composite cathode is 40-100 micrometers.

[0030] This invention discloses a composite positive electrode of a halide-containing electrolyte prepared by the above method.

[0031] This invention discloses an all-solid-state lithium-ion battery, comprising: the core-shell modified halide electrolyte described above; or, the composite cathode containing the halide electrolyte described above.

[0032] Preferably, in the preparation of all-solid-state lithium-ion batteries, metallic lithium or lithium alloy is used as the negative electrode material, which is stacked with a solid electrolyte film and a composite positive electrode to assemble and prepare an all-solid-state lithium-ion battery.

[0033] The present invention also discloses a method for preparing a solid electrolyte thin film.

[0034] Preferably, in the preparation of the solid electrolyte film, the solid electrolyte is mixed and ground with a polytetrafluoroethylene binder and shear force is applied to prepare the solid electrolyte film.

[0035] More preferably, in the preparation of the solid electrolyte film, the mass ratio of the solid electrolyte to the polytetrafluoroethylene binder is 1:0.005-0.02.

[0036] More preferably, in the preparation of the solid electrolyte film, the solid electrolyte includes sulfide solid electrolyte and halide solid electrolyte.

[0037] More preferably, in the preparation of the solid electrolyte film, the sulfide solid electrolyte includes Li6PS5Cl, Li 10 GeP2S 12 and Li7P3S 11 At least one of them.

[0038] More preferably, in the preparation of the solid electrolyte film, the halide solid electrolyte includes at least one of Li3InCl6, Li3YCl6 and Li2ZrCl6.

[0039] More preferably, in the preparation of the solid electrolyte film, the thickness of the solid electrolyte film is 0.05~0.3mm.

[0040] This invention discloses an all-solid-state lithium-ion battery, which uses metallic lithium or lithium alloy as the negative electrode material and stacks it with a solid electrolyte film and a composite positive electrode to assemble and prepare an all-solid-state lithium-ion battery.

[0041] Preferably, the lithium alloy is a Li-In alloy with a mass fraction of 0-3 wt%.

[0042] This invention employs an organically coordinated halide electrolyte as the lithium-ion conductor in a composite cathode. Compared to unmodified halide electrolytes, on the one hand, the steric hindrance introduced by the organic ligands can suppress the agglomeration tendency caused by the increase in surface energy after the particle size decreases; on the other hand, compared to crystalline electrolytes, the amorphous region on the surface of the organically coordinated halide electrolyte eliminates grain boundaries, increases the contact area between the cathode active material and the electrolyte inside the cathode, and improves ion transport efficiency.

[0043] The core-shell structure of the organic-coordinated modified halide electrolyte introduced in this invention significantly promotes its dispersibility in the composite cathode. Compared to the unmodified halide electrolyte, the organic ligands on the surface of this core-shell structure suppress the agglomeration tendency of the halide electrolyte during dispersion. Combined with dry hot rolling, this further promotes particle rearrangement, reduces the porosity of the composite cathode, constructs a more efficient lithium-ion transport network, and improves the electrolyte's performance and battery energy density. The amorphization of the organic-coordinated modified halide electrolyte's spherical shell eliminates grain boundaries on the electrolyte surface, increases the contact area between the electrolyte and the cathode active material, and ensures the cycle stability of the composite cathode due to good mechanical compatibility. The uniform and efficient lithium-ion transport channels constructed by the organic-coordinated modified halide electrolyte lead to uniform volume changes in the composite cathode, resulting in a self-compacting effect and further improving the cycle stability of the composite cathode. The all-solid-state lithium-ion battery using the composite cathode developed in this invention exhibits excellent cycle performance, high charge-discharge specific capacity, and good safety. Therefore, this invention provides a method for preparing a composite cathode containing a halide electrolyte that can be used to prepare all-solid-state lithium-ion batteries, resulting in lithium-ion batteries with good safety performance, high energy density, low impedance, high discharge capacity, and good long-cycle stability. Attached Figure Description

[0044] Figure 1 This is a SEM image of the core-shell modified halide electrolyte from Example 1.

[0045] Figure 2 This is a SEM image of the core-shell modified halide electrolyte from Example 2.

[0046] Figure 3 This is a SEM image of the composite cathode from Example 2. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0049] Example 1: A method for preparing a composite positive electrode containing a halide electrolyte. Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, the organic ligand was o-TCBQ, and the mass ratio of halide electrolyte to organic ligand was 1:0.005. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0050] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0051] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0052] Example 2: A method for preparing a composite positive electrode containing a halide electrolyte Preparation of core-shell modified halide electrolyte: The halide electrolyte and organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain the core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, the organic ligand was o-TCBQ, and the mass ratio of halide electrolyte to organic ligand was 1:0.01. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0053] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0054] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0055] Example 3: A method for preparing a composite positive electrode containing a halide electrolyte. Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, the organic ligand was o-TCBQ, and the mass ratio of halide electrolyte to organic ligand was 1:0.02. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0056] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0057] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0058] Example 4: A method for preparing a composite positive electrode containing a halide electrolyte Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, the organic ligand was p-TCBQ, and the mass ratio of halide electrolyte to organic ligand was 1:0.005. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0059] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0060] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0061] Example 5: A method for preparing a composite positive electrode containing a halide electrolyte. Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, and the organic ligand was p-TCBQ, with a mass ratio of halide electrolyte to organic ligand of 1:0.01. The ball milling was carried out in an inert gas atmosphere, using argon.

[0062] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0063] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0064] Example 6: A method for preparing a composite positive electrode containing a halide electrolyte Preparation of core-shell modified halide electrolyte: The halide electrolyte and organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain the core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, the organic ligand was p-TCBQ, and the mass ratio of halide electrolyte to organic ligand was 1:0.02. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0065] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0066] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0067] Example 7: A method for preparing a composite positive electrode containing a halide electrolyte Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, and the organic ligands were o-TCBQ and 2-amino-3-(3-indolyl)propionic acid. The mass ratio of halide electrolyte to organic ligand was 1:0.01, and the mass ratio of o-TCBQ to 2-amino-3-(3-indolyl)propionic acid was 1:0.8. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0068] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0069] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0070] Example 8: A method for preparing a composite positive electrode containing a halide electrolyte Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, and the organic ligands were o-TCBQ and 2-amino-3-(3-indolyl)propionic acid. The mass ratio of halide electrolyte to organic ligand was 1:0.01, and the mass ratio of o-TCBQ to 2-amino-3-(3-indolyl)propionic acid was 1:0.2. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0071] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0072] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0073] Example 9: A method for preparing a composite positive electrode containing a halide electrolyte Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, and the organic ligands were o-TCBQ, 2-amino-3-(3-indolyl)propionic acid, and cyanuric acid. The mass ratio of halide electrolyte to organic ligand was 1:0.01, and the mass ratio of o-TCBQ, 2-amino-3-(3-indolyl)propionic acid, and cyanuric acid was 1:0.8:0.4. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0074] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0075] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0076] Example 10: A method for preparing a composite positive electrode containing a halide electrolyte. Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, and the organic ligands were o-TCBQ, 2-amino-3-(3-indolyl)propionic acid, and cyanuric acid. The mass ratio of halide electrolyte to organic ligand was 1:0.01, and the mass ratio of o-TCBQ, 2-amino-3-(3-indolyl)propionic acid, and cyanuric acid was 1:0.8:0.1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0077] Preparation of composite cathode powder: Core-shell modified halide electrolyte, NCM83125, and conductive carbon were mixed and ball-milled at 100 rpm for 1 hour to obtain composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of core-shell modified halide electrolyte, NCM83125, and conductive carbon was 5.67:26.67:1. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0078] Preparation of the composite positive electrode: The composite positive electrode powder was ground and mixed with PTFE binder and rolled for 1 hour to obtain the composite positive electrode. The mass ratio of PTFE binder to composite positive electrode powder was 1:0.01. During the grinding and mixing process, the mixture was ball-milled at 100 rpm for 1 hour. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite positive electrode was 70 micrometers.

[0079] Comparative Example 1: A method for preparing a composite positive electrode containing a halide electrolyte The difference between this comparative example and Example 7 lies in the preparation of the core-shell modified halide electrolyte.

[0080] Preparation of core-shell modified halide electrolyte: A halide electrolyte and an organic ligand were mixed and ball-milled at 150 rpm for 1 h to obtain a core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, and the organic ligands were o-TCBQ and 2-amino-3-(3-indolyl)propionic acid. The mass ratio of halide electrolyte to organic ligand was 1:0.01, and the mass ratio of o-TCBQ to 2-amino-3-(3-indolyl)propionic acid was 1:0.02. The ball milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0081] Experimental example: The core-shell modified halide electrolyte prepared in Example 1 of this invention was subjected to scanning electron microscopy, and the results are as follows: Figure 1 As shown, the particle size range of the core-shell modified halide electrolyte prepared in Example 1 is 0.5~60 μm.

[0082] The core-shell modified halide electrolyte prepared in Example 2 of this invention was subjected to scanning electron microscopy, and the results are as follows: Figure 2 As shown, the particle size range of the core-shell modified halide electrolyte prepared in Example 2 is 0.1~50 μm.

[0083] The composite cathode prepared in Example 2 of this invention was subjected to scanning electron microscopy testing, and the results are as follows: Figure 3 As shown.

[0084] This invention involves assembling the following components in an argon glove box with both water and oxygen concentrations less than 0.1 ppm: a positive electrode shell, a positive electrode sheet, a solid electrolyte film, a lithium sheet, a gasket, a spring sheet, and a negative electrode shell. The assembly is then sealed using a fully automated sealing machine to obtain an all-solid-state lithium-ion battery. The positive electrode sheet is the composite positive electrode prepared in the examples and comparative examples. The lithium sheet is the negative electrode sheet.

[0085] The solid electrolyte film is a sulfide electrolyte film. The preparation method of the sulfide electrolyte film is as follows: the sulfide solid electrolyte Li6PS5Cl and polytetrafluoroethylene binder are mixed and ground in a ratio of 1:0.01 and shear force is applied to prepare an electrolyte film with a thickness of about 0.1 mm.

[0086] The obtained all-solid-state lithium-ion battery was subjected to constant current charge-discharge and electrochemical impedance testing using the Blue Battery Testing System and an electrochemical workstation. All electrochemical tests were conducted at 25°C.

[0087] The test results are shown in Table 1.

[0088] Table 1 Performance test results of all-solid-state lithium-ion batteries

[0089] The impedance results of the all-solid-state lithium-ion batteries in this invention are shown in Table 1. This invention first prepares a core-shell modified halide electrolyte by mixing a halide electrolyte and an organic ligand. Then, a composite cathode powder is prepared by mixing the core-shell modified halide electrolyte with NCM83125 and conductive carbon. Finally, a composite cathode is prepared by mixing the composite cathode powder with a binder. The organic material can be at least one of o-TCBQ, p-TCBQ, o-TFBQ, and p-TFBQ. The all-solid-state lithium-ion batteries assembled in Examples 1, 2, 3, 4, 5, and 6 have interfacial impedances of 34, 23, 32, 30, 36, and 45 μm before cycling, respectively. Ω; In preparing the core-shell modified halide electrolyte, 2-amino-3-(3-indolyl)propionic acid can also be added. After preparing the core-shell modified halide electrolyte using 2-amino-3-(3-indolyl)propionic acid and o-TCBQ, the interfacial impedances of all-solid-state lithium batteries containing the core-shell modified halide electrolytes of Examples 7, 8, and Comparative Example 1 before cycling are 21, 22, and 23 Ω, respectively. Furthermore, cyanuric acid can also be used as the organic material. After preparing the core-shell modified halide electrolyte using 2-amino-3-(3-indolyl)propionic acid, cyanuric acid, and o-TCBQ, the interfacial impedances of all-solid-state lithium batteries containing the core-shell modified halide electrolytes of Examples 9 and 10 before cycling are 19 and 20 Ω, respectively. This shows that the high-performance composite cathode provided by the present invention can improve the mass transfer kinetics of lithium ions and electrons at the electrode interface. Interfacial impedance can reflect the ion mass transfer kinetics at the electrode-electrolyte interface to some extent. The smaller the interfacial impedance, the better the kinetics of lithium ions at the electrode interface, which is more conducive to the electrochemical reaction and will further improve the electrochemical performance of the battery.

[0090] The discharge capacity results of the all-solid-state lithium-ion battery in this invention at a current density of 0.5C for the first / 200 cycles are shown in Table 1. This invention first prepares a core-shell modified halide electrolyte by mixing a halide electrolyte and an organic ligand. Then, a composite cathode powder is prepared by mixing the core-shell modified halide electrolyte with NCM83125 and conductive carbon. Finally, a composite cathode is prepared by mixing the composite cathode powder with a binder. The organic material can be at least one of o-TCBQ, p-TCBQ, o-TFBQ, and p-TFBQ. Constant current charge-discharge tests were conducted on the assembled batteries under a voltage range of 1.9-3.65 V and a current density of 0.5 C. The initial discharge capacities of the solid-state lithium-ion batteries assembled in Examples 1, 2, 3, 4, 5, and 6 were 166, 174, 154, 156, 141, and 128 mAh g, respectively. -1 In preparing the core-shell modified halide electrolyte, 2-amino-3-(3-indolyl)propionic acid can also be added. After preparing the core-shell modified halide electrolyte using 2-amino-3-(3-indolyl)propionic acid and o-TCBQ, the interfacial impedances of the all-solid-state lithium batteries containing the core-shell modified halide electrolytes of Examples 7, 8, and Comparative Example 1 before cycling were 181, 179, and 175 mAhg, respectively. -1 Furthermore, cyanuric acid can also be used as an organic compound. After preparing a core-shell modified halide electrolyte using 2-amino-3-(3-indolyl)propionic acid, cyanuric acid, and o-TCBQ, the interfacial impedances of all-solid-state lithium batteries containing the core-shell modified halide electrolytes of Examples 9 and 10 before cycling were 186 and 184 mAh g, respectively. -1 Example 2 showed a discharge capacity of 171 mAh g after 200 stable cycles. -1 Furthermore, no dramatic increase in polarization or short circuit occurred; after 200 stable cycles in Example 1, the discharge capacity was 146 mAh g. -1 Furthermore, no dramatic increase in polarization or short circuit occurred; in Example 3, the discharge capacity was 134 mAh g after 200 stable cycles. -1 Example 5 showed a discharge capacity of only 134 mAh g after 200 cycles. -1 This demonstrates that the high-performance composite cathode provided by this invention exhibits excellent long-cycle stability. In this invention, when the organic material is modified with o-TCBQ to modify the halide electrolyte, 2-amino-3-(3-indolyl)propionic acid and / or cyanuric acid can also be used together, resulting in a battery with higher initial discharge capacity and still possessing high discharge capacity after 100 cycles, demonstrating good long-cycle stability.

[0091] The discharge capacity results of the all-solid-state lithium-ion battery in this invention under 1C current density for the first / 500 cycles are shown in Table 1. The all-solid-state lithium-ion battery assembled in Example 2 was tested. Under a voltage range of 1.9-3.65 V and a current density of 0.1 C, its discharge capacity after 500 cycles was 148 mAh g⁻¹. -1 In this invention, the organic material can also be used in combination with o-TCBQ and 2-amino-3-(3-indolyl)propionic acid and / or cyanuric acid, resulting in a higher initial discharge capacity and a high discharge capacity even after 500 cycles; this demonstrates that the high-performance composite cathode provided by this invention still exhibits excellent long-cycle stability under conditions of high-activity material loading.

[0092] The embodiments and / or implementation methods described above are merely preferred embodiments and / or implementation methods for implementing the technology of the present invention, and are not intended to limit the implementation methods of the technology of the present invention in any way. Any person skilled in the art can make some modifications or alterations to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but they should still be regarded as the technology or embodiments that are substantially the same as the present invention.

[0093] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A method for preparing a core-shell modified halide electrolyte, comprising: A core-shell modified halide electrolyte was obtained by mixing halide electrolyte and organic ligand and then ball milling. The mass ratio of the halide electrolyte to the organic ligand is 1:0.003-0.

05.

2. The method for preparing a core-shell modified halide electrolyte according to claim 1, characterized in that: In the ball milling process, the ball milling is performed at a speed of 50-300 rpm for 0.5-5 hours.

3. The method for preparing a core-shell modified halide electrolyte according to claim 1, characterized in that: The halide electrolyte is at least one of Li3InCl6, Li3YCl6 and Li2ZrCl6; or the organic ligand is at least one of o-TCBQ, p-TCBQ, o-TFBQ and p-TFBQ.

4. The core-shell modified halide electrolyte obtained by any of the preparation methods described in claims 1-3.

5. A method for preparing a composite positive electrode containing a halide electrolyte, comprising: The method for preparing the core-shell modified halide electrolyte according to claim 1.

6. The method for preparing a composite positive electrode of a halide-containing electrolyte according to claim 5, characterized in that: A composite cathode powder was obtained by ball milling a core-shell modified halide electrolyte, NCM83125, and conductive carbon. The composite cathode powder was then ground, mixed with a binder, and rolled to obtain a composite cathode.

7. The method for preparing a composite positive electrode containing a halide electrolyte according to claim 6, characterized in that: The conductive carbon is at least one of Super P, acetylene black, Ketjen black, carbon nanofibers, carbon nanotubes, graphene, and graphene oxide.

8. The method for preparing a composite positive electrode containing a halide electrolyte according to claim 6, characterized in that: The mass ratio of the core-shell modified halide electrolyte, NCM83125, and conductive carbon used is 2-12:20-30:

1.

9. A composite positive electrode of a halide-containing electrolyte prepared by any one of the methods described in claims 5-8.

10. An all-solid-state lithium-ion battery, comprising: The core-shell modified halide electrolyte of claim 4; or the composite cathode of the halide-containing electrolyte of claim 9.

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