Method for preparing a composite positive electrode containing a halide electrolyte and use thereof

Abstract

The application discloses a preparation method of a composite positive electrode containing a halide electrolyte and application thereof, and belongs to the technical field of positive electrode materials of full solid-state lithium ion batteries, and particularly relates to mixing a halide electrolyte and an organic ligand, and obtaining a core-shell modified halide electrolyte through ball milling treatment; obtaining a composite positive electrode powder through ball milling treatment of the core-shell modified halide electrolyte, NCM83125 and conductive carbon; obtaining the composite positive electrode through grinding and mixing of the composite positive electrode powder and a binder and roller pressing. The application provides a core-shell modified halide electrolyte, the inner core is a halide electrolyte material, the outer layer is a coordination organic shell, and based on the steric hindance effect of the organic shell, the dispersion of the modified halide electrolyte in the composite positive electrode can be effectively promoted, the proportion of positive electrode active substances is improved, a good lithium ion conduction network is constructed, the energy density of the whole battery is improved, the positive electrode reaction kinetics is improved, and the capacity and rate performance of the battery are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of positive electrode materials of all-solid-state lithium ion batteries, and particularly relates to a preparation method of a composite positive electrode containing halide electrolyte and application thereof. BACKGROUND

[0002] With the wide application 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 have been difficult to meet the stringent requirements of new-generation electronic devices for high-energy-density energy storage systems due to the bottleneck of the theoretical capacity of electrode materials. More importantly, as the scale of battery energy storage continues to expand, safety issues have become increasingly prominent - the safety hazards such as leakage, flammability and explosiveness of traditional liquid electrolytes cannot be ignored. Under this background, the development of a new energy storage system with high energy density and excellent safety has become a top priority, which makes all-solid-state lithium ion batteries a research hotspot in the current energy storage field.

[0003] As the most critical component in all-solid-state lithium batteries, the performance of solid-state electrolyte 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, monovalent halogen ions in halide electrolytes have larger ionic radius, weaker lithium ion interaction and higher redox potential, which makes halide electrolytes the most advanced positive electrolyte filler in current all-solid-state lithium ion batteries, exhibiting excellent lithium ion transference rate, processability and electrochemical stability.

[0004] Although halide electrolytes have been widely used in all-solid-state lithium batteries, the composite positive electrode based on halide electrolytes still faces the problem of limited capacity. Due to the large particle size of halide electrolyte, up to 30% mass fraction of halide electrolyte needs to be added in the composite positive electrode, which limits the utilization rate of active materials. High-energy ball milling is a common method to reduce the particle size of electrolyte and construct a percolated ion conduction network. However, the mechanical crushing process will cause serious degradation of the crystal structure of halide electrolyte and generate high surface energy, which will trigger strong thermodynamic agglomeration tendency, thereby affecting the dispersion uniformity of halide electrolyte particles in the composite positive electrode. In addition, the grain boundaries existing in the crystalline halide electrolyte will hinder the achievement of high relative density during plastic deformation, thereby affecting the interface contact between halide electrolyte and active material, leading to interface contact failure. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of a composite positive electrode containing halide electrolyte, which can be used to prepare all-solid-state lithium ion batteries, has good safety performance, high energy density, low impedance, high discharge capacity and good long cycle stability after the lithium ion battery is prepared.

[0006] The technical scheme adopted by the present application to achieve the above-mentioned purpose is:

[0007] A preparation method of a core-shell modified halide electrolyte, comprising: mixing a halide electrolyte and an organic ligand, and obtaining the core-shell modified halide electrolyte after ball milling treatment; the mass ratio of the use amount of the halide electrolyte to the organic ligand is 1:0.003-0.05. The core-shell modified halide electrolyte is an organic ligand coordinated modified halide electrolyte, has a core-shell structure, the inner core is a halide electrolyte material, and the outer layer is an organic shell. The core-shell modified halide electrolyte can be used to prepare a composite positive electrode. The core-shell structure of the core-shell modified halide electrolyte has a good promoting effect on the dispersibility thereof in the composite positive electrode. Compared with the unmodified halide electrolyte, the organic ligand on the surface of the core-shell structure inhibits the agglomeration tendency of the halide electrolyte in the dispersion process, further promotes the particle rearrangement in combination with the dry hot rolling effect, reduces the porosity in the composite positive electrode, constructs a more efficient lithium ion transmission network, and improves the use efficiency of the electrolyte in the composite positive electrode and the battery energy density.

[0008] Preferably, in the ball milling treatment, the ball milling treatment is performed at a rotation speed of 50-300 rpm for 0.5-5 h.

[0009] Preferably, the halide electrolyte is a crystalline halide electrolyte.

[0010] 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.

[0011] Preferably, the ball milling treatment is performed in an inert gas atmosphere. The inert gas is argon.

[0012] Preferably, the core-shell modified halide electrolyte is an electrolyte with a surface amorphous state wrapping an internal crystalline state, and the particle size is 0.1-60 μm.

[0013] Preferably, in the preparation of the core-shell modified halide electrolyte, the halide electrolyte and the organic ligand are mixed, and the ball milling treatment is performed at a rotation speed of 50-300 rpm for 0.5-5 h to obtain the core-shell modified halide electrolyte.

[0014] More preferably, in the preparation of the core-shell modified halide electrolyte, the halide electrolyte is at least one of Li3InCl6, Li3YCl6, and Li2ZrCl6.

[0015] 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.

[0016] More preferably, in the preparation of the core-shell modified halide electrolyte, the mass ratio of the halide electrolyte to the amount of the organic ligand used is 1:0.003-0.05.

[0017] More preferably, in the preparation of the core-shell modified halide electrolyte, the organic ligand further includes o-TCBQ and 2-amino-3-(3-indolyl) propionic acid, and the mass ratio of the amount of o-TCBQ to the amount of 2-amino-3-(3-indolyl) propionic acid used is 1:0.1-1. After the coordination modification of the halide electrolyte by o-TCBQ and 2-amino-3-(3-indolyl) propionic acid, the amorphization of the spherical shell eliminates the grain boundaries on the surface of the electrolyte, improves the contact area of the electrolyte and the positive active material, and the good mechanical compatibility ensures the cycle stability of the composite positive electrode. The uniform and efficient lithium ion transmission channel constructed by the coordination modification of the halide electrolyte by o-TCBQ and 2-amino-3-(3-indolyl) propionic acid leads to uniform volume change in the composite positive electrode, thereby producing a self-densification effect, further improving the cycle stability of the full solid-state lithium ion battery prepared from the composite positive electrode.

[0018] 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, and the mass ratio of the amount of o-TCBQ to the amount of 2-amino-3-(3-indolyl) propionic acid to the amount of cyanuric acid used is 1:0.1-1:0.05-0.5. In the present application, after o-TCBQ and 2-amino-3-(3-indolyl) propionic acid are used, cyanuric acid can be further added to form a spherical shell formed by o-TCBQ, 2-amino-3-(3-indolyl) propionic acid and cyanuric acid, which further improves the performance of the composite positive electrode and improves the cycle stability of the full solid-state lithium ion battery prepared from the composite positive electrode.

[0019] The core-shell modified halide electrolyte obtained by the above preparation method is disclosed.

[0020] A preparation method of a composite positive electrode containing a halide electrolyte is disclosed, comprising: the preparation method of the core-shell modified halide electrolyte described above.

[0021] Preferably, the composite positive electrode powder is obtained after the core-shell modified halide electrolyte, NCM83125 and conductive carbon are ball milled; the composite positive electrode is obtained after the composite positive electrode powder is ground and mixed with a binder and then rolled.

[0022] More preferably, the conductive carbon is at least one of Super P, acetylene black, Ketjen black, carbon nanofiber, carbon nanotube, graphene and graphene oxide.

[0023] More preferably, the mass ratio of the use amount of the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon is 2-12:20-30:1.

[0024] Preferably, in the preparation of the composite positive electrode powder, the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon are mixed and ball milled at a speed of 50-300 rpm for 0.5-5 h to obtain the composite positive electrode powder.

[0025] More preferably, in the preparation of the composite positive electrode powder, the conductive carbon is at least one of Super P, carbon nanotube and carbon nanofiber.

[0026] More preferably, in the preparation of the composite positive electrode powder, the mass ratio of the use amount of the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon is 2-12:20-30:1.

[0027] Preferably, in the preparation of the composite positive electrode, the composite positive electrode powder and the PTFE binder are mixed and ground and rolled for 0.2-3 h to obtain the composite positive electrode.

[0028] More preferably, in the preparation of the composite positive electrode, the mass ratio of the use amount of the PTFE binder and the composite positive electrode powder is 1:0.005-0.02.

[0029] More preferably, in the preparation of the composite positive electrode, the mixing and grinding are carried out by ball milling at a speed of 50-300 rpm for 0.5-5 h.

[0030] More preferably, in the preparation of the composite positive electrode, the thickness of the composite positive electrode is 40-100 microns.

[0031] The application discloses a composite positive electrode containing a halide electrolyte prepared by the above method.

[0032] The application discloses a full solid-state lithium ion battery, comprising: the above-mentioned core-shell modified halide electrolyte; or the above-mentioned composite positive electrode containing a halide electrolyte.

[0033] Preferably, in the preparation of the full solid-state lithium ion battery, a metal lithium or a lithium alloy is used as a negative electrode material, stacked with a solid-state electrolyte thin film and a composite positive electrode sheet to assemble and prepare the full solid-state lithium ion battery.

[0034] The application further discloses a preparation method of a solid-state electrolyte thin film.

[0035] Preferably, in the preparation of the solid electrolyte thin film, the solid electrolyte is mixed, ground and sheared with the polytetrafluoroethylene binder to prepare the solid electrolyte thin film.

[0036] More preferably, in the preparation of the solid electrolyte thin film, the mass ratio of the use amount of the polytetrafluoroethylene binder to the solid electrolyte is 1:0.005-0.02.

[0037] More preferably, in the preparation of the solid electrolyte thin film, the solid electrolyte comprises a sulfide solid electrolyte and a halide solid electrolyte.

[0038] More preferably, in the preparation of the solid electrolyte thin film, the sulfide solid electrolyte comprises at least one of Li6PS5Cl, Li 10 GeP2S 12 and Li7P3S 11 .

[0039] More preferably, in the preparation of the solid electrolyte thin film, the halide solid electrolyte comprises at least one of Li3InCl6, Li3YCl6 and Li2ZrCl6.

[0040] More preferably, in the preparation of the solid electrolyte thin film, the thickness of the solid electrolyte thin film is 0.05-0.3 mm.

[0041] The application discloses a full solid-state lithium ion battery, which is prepared by stacking a solid electrolyte thin film and a composite positive electrode sheet with metal lithium or a lithium alloy as a negative electrode material.

[0042] Preferably, the lithium alloy is a Li-In alloy with a mass fraction of 0-3 wt%.

[0043] The application adopts an organic coordination modified halide electrolyte as a lithium ion conductor in the composite positive electrode. Compared with the unmodified halide electrolyte, on the one hand, due to the steric hindance effect of the organic ligand, the agglomeration tendency caused by the increase of surface energy after the reduction of particle size can be inhibited; on the other hand, compared with the crystalline electrolyte, the amorphous region on the surface of the organic coordination modified halide electrolyte eliminates the grain boundary, improves the contact area of the positive electrode active material and the electrolyte in the positive electrode, and improves the ion transmission efficiency.

[0044] The core-shell structure of the organic coordination modified halide electrolyte introduced in the composite positive electrode has a good promoting effect on the dispersibility of the composite positive electrode. Compared with the unmodified halide electrolyte, the organic ligand on the surface of the core-shell structure inhibits the agglomeration tendency of the halide electrolyte in the dispersion process, and in combination with the dry hot rolling effect, further promotes the particle rearrangement, reduces the porosity in the composite positive electrode, constructs a more efficient lithium ion transmission network, and improves the use efficiency of the electrolyte in the composite positive electrode and the energy density of the battery. The amorphization of the organic coordination modified halide electrolyte shell eliminates the grain boundaries on the surface of the electrolyte, improves the contact area between the electrolyte and the positive active material, and the good mechanical compatibility ensures the cycle stability of the composite positive electrode. The uniform and efficient lithium ion transmission channel constructed by the organic coordination modified halide electrolyte leads to uniform volume change in the composite positive electrode, thereby producing a self-densification effect, further improving the cycle stability of the composite positive electrode. The full solid-state lithium ion battery using the composite positive electrode developed by the application has the characteristics of excellent cycle performance, high charge-discharge specific capacity, good safety, etc. Therefore, the application is a composite positive electrode containing halide electrolyte preparation method which can prepare full solid-state lithium ion batteries, has good safety performance, high energy density, low impedance, high discharge capacity and long cycle stability after the lithium ion battery is prepared. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 SEM image of the core-shell type modified halide electrolyte of Example 1.

[0046] Figure 2 SEM image of the core-shell type modified halide electrolyte of Example 2.

[0047] Figure 3 SEM image of the composite positive electrode of Example 2. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the application will be described clearly and completely in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0049] The concepts involved in the present application will be described below in combination with the drawings. It should be pointed out here that the following descriptions of the concepts are only to make the content of the present application easier to understand, and do not represent the limitation of the protection scope of the present application; meanwhile, the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0050] Example 1: A preparation method of a composite cathode containing halide electrolyte

[0051] Preparation of core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a speed of 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 the use amounts of the halide electrolyte and the organic ligand was 1:0.005. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0052] Preparation of composite cathode powder: the core-shell modified halide electrolyte, the NCM83125, and the conductive carbon were mixed and ball-milled at a speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, the mass ratio of the use amounts of the core-shell modified halide electrolyte, the NCM83125, and the conductive carbon was 5.67:26.67:1. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0053] Preparation of composite cathode: the composite cathode powder and the PTFE binder were ground and mixed and roll-pressed for 1 h to obtain the composite cathode. The mass ratio of the use amounts of the PTFE binder and the composite cathode powder was 1:0.01. In the grinding and mixing, the ball-milling was performed at a speed of 100 rpm for 1 h. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0054] Example 2: A preparation method of a composite cathode containing halide electrolyte

[0055] Preparation of core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a speed of 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 the use amounts of the halide electrolyte and the organic ligand was 1:0.01. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

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

[0057] Preparation of the composite cathode: the composite cathode powder was mixed with the PTFE binder by grinding and roll-pressed for 1 h to obtain the composite cathode. The mass ratio of the use amount of the PTFE binder to the composite cathode powder was 1:0.01. In the grinding and mixing, the ball milling treatment was performed at a speed of 100 rpm for 1 h. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0058] Example 3: A preparation method of a composite cathode containing a halide electrolyte

[0059] Preparation of the core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a speed of 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 the use amount of the halide electrolyte to the organic ligand was 1:0.02. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon.

[0060] Preparation of the composite cathode powder: the core-shell modified halide electrolyte, the NCM83125, and the conductive carbon were mixed and ball-milled at a speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of the use amount of the core-shell modified halide electrolyte, the NCM83125, and the conductive carbon was 5.67:26.67:1. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon.

[0061] Preparation of the composite cathode: the composite cathode powder was mixed with the PTFE binder by grinding and roll-pressed for 1 h to obtain the composite cathode. The mass ratio of the use amount of the PTFE binder to the composite cathode powder was 1:0.01. In the grinding and mixing, the ball milling treatment was performed at a speed of 100 rpm for 1 h. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0062] Example 4: A preparation method of a composite cathode containing a halide electrolyte

[0063] Preparation of the core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a speed of 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 the use amount of the halide electrolyte to the organic ligand was 1:0.005. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon.

[0064] Preparation of the composite cathode powder: the core-shell modified halide electrolyte, NCM 83125 and conductive carbon were mixed and ball-milled at a rotation speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of the use amount of the core-shell modified halide electrolyte, NCM 83125 and conductive carbon was 5.67:26.67:1. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0065] Preparation of the composite cathode: the composite cathode powder and PTFE binder were mixed and roll-pressed for 1 h to obtain the composite cathode. The mass ratio of the use amount of the PTFE binder and the composite cathode powder was 1:0.01. In the mixing, the ball-milling was performed at a rotation speed of 100 rpm for 1 h. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0066] Example 5: A preparation method of a composite cathode containing a halide electrolyte

[0067] Preparation of the core-shell modified halide electrolyte: the halide electrolyte and organic ligand were mixed and ball-milled at a rotation speed of 150 rpm for 1 h to obtain the core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, and the organic ligand was p-TCBQ. The mass ratio of the use amount of the halide electrolyte and the organic ligand was 1:0.01. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0068] Preparation of the composite cathode powder: the core-shell modified halide electrolyte, NCM 83125 and conductive carbon were mixed and ball-milled at a rotation speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of the use amount of the core-shell modified halide electrolyte, NCM 83125 and conductive carbon was 5.67:26.67:1. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0069] Preparation of the composite cathode: the composite cathode powder and PTFE binder were mixed and roll-pressed for 1 h to obtain the composite cathode. The mass ratio of the use amount of the PTFE binder and the composite cathode powder was 1:0.01. In the mixing, the ball-milling was performed at a rotation speed of 100 rpm for 1 h. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0070] Example 6: A preparation method of a composite cathode containing a halide electrolyte

[0071] Preparation of core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a rotation speed of 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 the use amount of the halide electrolyte to the organic ligand was 1:0.02. The ball-milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0072] Preparation of composite cathode powder: the core-shell modified halide electrolyte, the NCM83125, and the conductive carbon were mixed and ball-milled at a rotation speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, the mass ratio of the use amount of the core-shell modified halide electrolyte, the NCM83125, and the conductive carbon was 5.67:26.67:1. The ball-milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0073] Preparation of composite cathode: the composite cathode powder and the PTFE binder were ground and mixed and roll-pressed for 1 h to obtain the composite cathode. The mass ratio of the use amount of the PTFE binder to the composite cathode powder was 1:0.01. In the grinding and mixing, the ball-milling was carried out at a rotation speed of 100 rpm for 1 h. The ball-milling was carried out in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0074] Example 7: A preparation method of a composite cathode containing a halide electrolyte

[0075] Preparation of core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a rotation speed of 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 2-amino-3-(3-indolyl)propionic acid, and the mass ratio of the use amount of the halide electrolyte to the organic ligand was 1:0.01, and the mass ratio of the use amount 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.

[0076] Preparation of composite cathode powder: the core-shell modified halide electrolyte, the NCM83125, and the conductive carbon were mixed and ball-milled at a rotation speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, the mass ratio of the use amount of the core-shell modified halide electrolyte, the NCM83125, and the conductive carbon was 5.67:26.67:1. The ball-milling was carried out in an inert gas atmosphere. The inert gas was argon.

[0077] Preparation of the composite cathode: the composite cathode powder and the PTFE binder were mixed by grinding and rolling for 1 h to obtain the composite cathode. The mass ratio of the use amount of the PTFE binder to the composite cathode powder was 1:0.01. In the grinding and mixing, the ball milling treatment was performed at a speed of 100 rpm for 1 h. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0078] Example 8: A preparation method of a composite cathode containing a halide electrolyte

[0079] Preparation of the core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a speed of 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 2-amino-3-(3-indolyl)propionic acid, the mass ratio of the use amount of the halide electrolyte to the organic ligand was 1:0.01, and the mass ratio of the use amount of o-TCBQ to 2-amino-3-(3-indolyl)propionic acid was 1:0.2. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon.

[0080] Preparation of the composite cathode powder: the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon were mixed and ball-milled at a speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of the use amount of the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon was 5.67:26.67:1. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon.

[0081] Preparation of the composite cathode: the composite cathode powder and the PTFE binder were mixed by grinding and rolling for 1 h to obtain the composite cathode. The mass ratio of the use amount of the PTFE binder to the composite cathode powder was 1:0.01. In the grinding and mixing, the ball milling treatment was performed at a speed of 100 rpm for 1 h. The ball milling treatment was performed in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0082] Example 9: A preparation method of a composite cathode containing a halide electrolyte

[0083] Preparation of the core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a rotation speed of 150 rpm for 1 h to obtain the core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, the organic ligand was o-TCBQ, 2-amino-3-(3-indolyl)propionic acid and cyanuric acid, and the mass ratio of the use amounts of the halide electrolyte and the organic ligand was 1:0.01, and the mass ratio of the use amounts of o-TCBQ, 2-amino-3-(3-indolyl)propionic acid and cyanuric acid was 1:0.8:0.4. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0084] Preparation of the composite cathode powder: the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon were mixed and ball-milled at a rotation speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of the use amounts of the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon was 5.67:26.67:1. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0085] Preparation of the composite cathode: the composite cathode powder and the PTFE binder were ground and mixed and roll-pressed for 1 h to obtain the composite cathode. The mass ratio of the use amounts of the PTFE binder and the composite cathode powder was 1:0.01. In the grinding and mixing, the ball-milling was performed at a rotation speed of 100 rpm for 1 h. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon. The thickness of the composite cathode was 70 microns.

[0086] Example 10: A preparation method of a composite cathode containing a halide electrolyte

[0087] Preparation of the core-shell modified halide electrolyte: the halide electrolyte and the organic ligand were mixed and ball-milled at a rotation speed of 150 rpm for 1 h to obtain the core-shell modified halide electrolyte. The halide electrolyte was Li3InCl6, the organic ligand was o-TCBQ, 2-amino-3-(3-indolyl)propionic acid and cyanuric acid, and the mass ratio of the use amounts of the halide electrolyte and the organic ligand was 1:0.01, and the mass ratio of the use amounts of o-TCBQ, 2-amino-3-(3-indolyl)propionic acid and cyanuric acid was 1:0.8:0.1. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0088] Preparation of the composite cathode powder: the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon were mixed and ball-milled at a rotation speed of 100 rpm for 1 h to obtain the composite cathode powder. The conductive carbon was carbon nanofiber, and the mass ratio of the use amounts of the core-shell modified halide electrolyte, the NCM83125 and the conductive carbon was 5.67:26.67:1. The ball-milling was performed in an inert gas atmosphere. The inert gas was argon.

[0089] 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.

[0090] Comparative Example 1: A method for preparing a composite positive electrode containing a halide electrolyte

[0091] The difference between this comparative example and Example 7 lies in the preparation of the core-shell modified halide electrolyte.

[0092] 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.

[0093] Experimental example:

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] The solid electrolyte thin film is a sulfide electrolyte thin film, and the sulfide electrolyte thin film is prepared by the following method: sulfide solid electrolyte Li6PS5Cl and polytetrafluoroethylene binder are mixed, ground and sheared at a ratio of 1:0.01 to prepare an electrolyte thin film with a thickness of about 0.1 mm.

[0099] The obtained all-solid-state lithium ion battery is subjected to constant current charge and discharge and electrochemical impedance test by using a blue battery test system and an electrochemical workstation, and the electrochemical test is carried out at 25 DEG C.

[0100] The test results are shown in Table 1.

[0101] Table 1: Performance test results of all-solid-state lithium ion battery

[0102]

[0103] The impedance results of the all-solid-state lithium ion battery in the application are shown in Table 1. The core-shell modified halide electrolyte is prepared by mixing the halide electrolyte and the organic ligand, then the composite positive electrode powder is prepared by mixing the core-shell modified halide electrolyte, NCM83125 and conductive carbon, and finally the composite positive electrode is prepared by mixing the composite positive electrode powder and the binder. The organic matter can use at least one of o-TCBQ, p-TCBQ, o-TFBQ and p-TFBQ. The interfacial impedance of the all-solid-state lithium ion battery assembled by Example 1, Example 2, Example 3, Example 4, Example 5 and Example 6 before cycling is 34, 23, 32, 30, 36 and 45 Ω respectively. When preparing the core-shell modified halide electrolyte, 2-amino-3-(3-indolyl) propionic acid can also be added. After using 2-amino-3-(3-indolyl) propionic acid and o-TCBQ to prepare the core-shell modified halide electrolyte, the interfacial impedance of the all-solid-state lithium battery containing the core-shell modified halide electrolyte of Example 7, Example 8 and Comparative Example 1 before cycling is 21, 22 and 23 Ω respectively. Further organic matter can use cyanuric acid. After using 2-amino-3-(3-indolyl) propionic acid, cyanuric acid and o-TCBQ to prepare the core-shell modified halide electrolyte, the interfacial impedance of the all-solid-state lithium battery containing the core-shell modified halide electrolyte of Example 9 and Example 10 before cycling is 19 and 20 Ω respectively. It shows that the high-performance composite positive electrode provided by the application can improve the mass transfer kinetics of lithium ions and electrons at the electrode interface. The interfacial impedance can reflect the ion mass transfer kinetics at the electrode and electrolyte interface to some extent. The smaller the interfacial impedance, the better the kinetics of lithium ions at the electrode interface, which is conducive to the electrochemical reaction and further improves the electrochemical performance of the battery.

[0104] The first circle / 200 circle discharge capacity results of the all-solid-state lithium ion battery in the application under 0.5 C current density are shown in Table 1. The core-shell type modified halide electrolyte is prepared by mixing halide electrolyte and organic ligand, then the composite positive electrode powder is prepared by mixing the core-shell type modified halide electrolyte, NCM83125 and conductive carbon, and finally the composite positive electrode is prepared by mixing the composite positive electrode powder and the binder. The organic matter can be at least one of o-TCBQ, p-TCBQ, o-TFBQ and p-TFBQ. Under the condition of 1.9-3.65 V voltage interval and 0.5 C current density, the assembled battery is tested by constant current charge and discharge. The initial discharge capacity of the solid-state lithium ion battery assembled by Example 1, Example 2, Example 3, Example 4, Example 5 and Example 6 is 166, 174, 154, 156, 141 and 128 mAh g respectively -1 When preparing the core-shell type modified halide electrolyte, 2-amino-3-(3-indolyl) propionic acid can also be added. After using 2-amino-3-(3-indolyl) propionic acid and o-TCBQ together to prepare the core-shell type modified halide electrolyte, the interfacial impedance of the all-solid-state lithium battery containing the core-shell type modified halide electrolyte of Example 7, Example 8 and Comparative Example 1 before cycling is 181, 179 and 175 mAh g respectively -1 Further, the organic matter can also use cyanuric acid. After using 2-amino-3-(3-indolyl) propionic acid, cyanuric acid and o-TCBQ together to prepare the core-shell type modified halide electrolyte, the interfacial impedance of the all-solid-state lithium battery containing the core-shell type modified halide electrolyte of Example 9 and Example 10 before cycling is 186 and 184 mAh g respectively -1 ; the discharge capacity of Example 2 after stable cycling for 200 cycles is 171 mAh g -1 , and there is no dramatic increase in polarization and short circuit; the discharge capacity of Example 1 after stable cycling for 200 cycles is 146 mAh g -1 , and there is no dramatic increase in polarization and short circuit; the discharge capacity of Example 3 after stable cycling for 200 cycles is 134 mAh g -1 ; the discharge capacity of Example 5 after cycling for 200 cycles is only 134 mAh g -1 ; it shows that the high-performance composite positive electrode provided by the application has excellent long cycle stability. When the organic matter is modified by o-TCBQ on the halide electrolyte in the application, 2-amino-3-(3-indolyl) propionic acid and / or cyanuric acid can also be used together, and the battery obtained has higher first circle discharge capacity and higher discharge capacity after 100 cycles, and has good long cycle stability.

[0105] The first circle / 500 circle discharge capacity results of the all-solid-state lithium ion battery in the application under 1C current density are shown in Table 1. The all-solid-state lithium ion battery of Example 2 is assembled and tested, and under the condition of a voltage range of 1.9-3.65 V and a current density of 0.1 C, the discharge capacity of the battery under the condition of 500 cycles is 148 mAh g -1 The organic matter in the application can also be used together with o-TCBQ, 2-amino-3-(3-indolyl) propionic acid and / or cyanuric acid, which has higher first circle discharge capacity and higher discharge capacity after 500 cycles, indicating that the high-performance composite positive electrode provided by the application still has excellent long cycle stability under the condition of high active material load.

[0106] The above-described examples and / or embodiments are only used to illustrate the preferred embodiments and / or implementations of the application, and do not limit the embodiments of the application in any form. Any person skilled in the art can make some changes or modifications to other equivalent embodiments without departing from the scope of the technology disclosed in the application, but should be considered as the same technology or embodiment as the application.

[0107] The principles and implementations of the application are described by using specific examples in this paper, and the above example descriptions are only used to help understand the method and core idea of the application. The above-mentioned preferred embodiments of the application should be noted that due to the limited expression of the text, there are infinite specific structures, and for ordinary skilled persons in the art, without departing from the principles of the application, some improvements, refinements or changes can be made, and the above technical features can be combined in an appropriate way; these improvements, refinements, changes or combinations, or the application of the concept and technical scheme of the application to other occasions without improvement, should be considered as the protection scope of the application.

Claims

1. A method for preparing a core-shell modified halide electrolyte, comprising: The halide electrolyte and organic ligand were mixed and ball-milled to obtain a core-shell modified halide electrolyte. The mass ratio of the halide electrolyte to the organic ligand used is 1:0.003-0.05; The halide electrolyte is at least one of Li3InCl6, Li3YCl6 and Li2ZrCl6; the organic ligand is o-TCBQ and 2-amino-3-(3-indolyl)propionic acid, and the mass ratio of o-TCBQ to 2-amino-3-(3-indolyl)propionic acid is 1:0.2-0.

8.

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 core-shell modified halide electrolyte obtained by any of the preparation methods described in claims 1-2.

4. 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.

5. The method for preparing a composite positive electrode containing a halide electrolyte according to claim 4, 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.

6. The method for preparing a composite positive electrode containing a halide electrolyte according to claim 5, 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.

7. The method for preparing a composite positive electrode of a halide-containing electrolyte according to claim 5, characterized in that: The mass ratio of the core-shell modified halide electrolyte, NCM83125, and conductive carbon used is 2-12:20-30:

1.

8. A composite cathode of a halide-containing electrolyte prepared by any of the methods described in claims 4-7.

9. An all-solid-state lithium-ion battery, comprising: The core-shell modified halide electrolyte of claim 3; Alternatively, the composite cathode of the halide-containing electrolyte as described in claim 8.

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