CN110165152B

CN110165152B - Solid-state positive electrode composite material, preparation method and application thereof

Info

Publication number: CN110165152B
Application number: CN201810139903.6A
Authority: CN
Inventors: 李静; 胡晨吉; 沈炎宾; 卢威; 吴晓东; 陈立桅
Original assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Current assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Priority date: 2018-02-11
Filing date: 2018-02-11
Publication date: 2020-08-28
Anticipated expiration: 2038-02-11
Also published as: CN110165152A

Abstract

The invention discloses a solid-state anode composite material, a preparation method and application thereof. The solid state positive electrode composite material comprises: a continuous organic phase formed by the aggregation of organic fibrous material having at least the function of an ion conductor; a positive active material distributed in pores contained in the continuous organic phase; and the electrolyte salt is distributed in the organic fiber material and in holes contained in a network structure formed by the organic fiber material and the positive active material. The solid-state anode composite material is in a flexible film form. The solid-state anode composite material has the characteristics of flexibility, high ionic conductivity, high electronic conductivity, excellent processing performance, excellent electrochemical performance and the like.

Description

Solid-state positive electrode composite material, preparation method and application thereof

Technical Field

The invention relates to a positive electrode material, in particular to a flexible solid positive electrode composite material, a flexible solid positive electrode, a preparation method of the flexible solid positive electrode and application of the flexible solid positive electrode in an electrochemical device, and belongs to the field of electrochemistry.

Background

In the last 20 years, with the rapid development of the portable consumer electronics industry, the lithium ion battery has been commercialized with great success due to high energy density, good cycle performance and rate capability. However, lithium ion battery safety accidents that have occurred continuously over the past decades have been a concern in the field.

The lithium ion battery has the potential hazards of fire and explosion due to the fact that the internal temperature of the battery is too high due to internal short circuit or other reasons, and the most important reason is that high-temperature inflammable organic electrolyte is used as a lithium ion conductive network. Therefore, once the internal temperature of the battery reaches the ignition point of the organic solvent for various reasons (such as internal short circuit of the battery), ignition or even explosion of the battery is caused, and the higher the energy density of the battery, the greater the hazard. This safety problem exists as early as the birth of lithium ion batteries. Research in recent decades suggests that it is possible to fundamentally solve this safety hazard by developing all solid-state lithium ion batteries.

Particularly, in the all-solid-state battery, because no flammable and easily-degradable organic solvent exists, the safety performance of the battery can be greatly improved, and meanwhile, the battery does not have the problems of liquid leakage, electrolyte dryness, air inflation and the like which influence the electrochemical performance of the battery. Moreover, the all-solid-state battery has smaller mass, higher volume energy density and more flexible design and assembly. Therefore, the development of all solid-state lithium ion batteries that are not flammable is a necessary choice for the next generation of batteries to develop high safety, high energy density, high power density, and long cycle life. However, the popularization and application of the all-solid-state battery are limited by many technical aspects, and the development of the high-conductivity solid electrolyte and the construction of the electronic ion conductive network in the anode and the cathode have many technical challenges.

Generally, an important requirement for the battery to be able to operate is the rapid conduction of electrons and ions in the system in a continuous network of ionic conductors. For a liquid battery, the liquid can flow and can be continuously filled in the battery, and each electrode material particle is connected, so that the transmission of ions is naturally not problematic. For the quasi-solid battery which is industrialized at present, the gel-state electrolyte can flow and is well filled in the battery, and the transmission of ions is not problematic when each electrode material particle is connected. However, in all-solid batteries, even if the solid particles are in close contact with each other in the battery, the solid particles are usually in a point-to-point contact state, and ion transport between the particles is particularly difficult.

At present, inorganic ion conductors, conductive carbon and adhesives are mixed with positive active materials and then coated into pole pieces in the existing solid positive preparation technology, but the ionic and electronic conductive networks are constructed by the method, the electronic conductivity is not too large, but the contact between the ionic conductors and the positive materials is still point-to-point contact, the interface impedance is larger, and meanwhile, the pole pieces contain the adhesives, so that the transmission of lithium ions is easily hindered, and the ionic conductive networks still have larger problems. Therefore, the development of a solid-state positive electrode with high electron ion conductivity is an important research direction for realizing the industrialization of all-solid-state batteries.

Disclosure of Invention

The invention mainly aims to provide a solid-state positive electrode composite material and a solid-state positive electrode so as to overcome the defects in the prior art.

Another objective of the present invention is to provide a solid-state positive electrode composite material and a method for preparing a solid-state positive electrode.

The invention also provides a solid positive electrode composite material and application of the solid positive electrode.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

the embodiment of the invention provides a solid-state anode composite material, which comprises the following components:

a continuous organic phase formed by the aggregation of organic fibrous material having at least the function of an ion conductor;

a positive active material distributed in pores contained in the continuous organic phase;

electrolyte salt distributed in the organic fiber material and in pores of the network structure formed by the organic fiber material and the positive electrode active material;

optionally adding an electronic conductor additive which is dispersed in the solid positive electrode composite material; and the number of the first and second groups,

optionally adding inorganic ion conductor additive dispersed in the solid positive electrode composite material;

and the solid-state positive electrode composite material is in a flexible film form and has a thickness of 30-500 mu m.

In some preferred embodiments, the solid state positive electrode composite comprises:

a continuous two-or three-dimensional structure formed primarily by the intimate aggregation of the organic fibrous material;

a positive electrode active material dispersed in the two-dimensional or three-dimensional structure; and the number of the first and second groups,

and the electrolyte salt is dispersed in holes contained in a network structure formed by the organic fiber material and the positive electrode active material.

In some preferred embodiments, the organic fibrous material also has an electronic conductor function.

Preferably, the solid-state positive electrode composite material further comprises an electronic conductor additive dispersed in the solid-state positive electrode composite material.

Preferably, the solid positive electrode composite material further comprises an inorganic ion conductor additive dispersed in the solid positive electrode composite material.

In the embodiment of the invention, the continuous organic phase is formed by adopting the organic fiber material, so that a large number of special interface ion transport channels can be provided by utilizing the organic fibers, and the ionic conductivity of the solid-state positive electrode composite material is greatly improved.

The embodiment of the invention also provides a solid-state positive electrode composite material which is mainly formed by pressurizing the composite material and then soaking the composite material by electrolyte salt solution;

the composite material comprises:

the continuous organic phase is a continuous two-dimensional or three-dimensional structure formed by spraying a polymer solution onto a selected receiving surface by adopting an electrostatic spinning technology, and the organic fiber material at least has an ion conductor function;

spraying a dispersion of a positive electrode active material or a mixed dispersion of the positive electrode active material and an electron conductor additive and/or an inorganic ion conductor additive onto the selected receiving surface by an electrostatic spraying technique while spraying the polymer solution,

the electrolyte salt is distributed in the organic fiber material and in the holes contained in the network structure formed by the organic fiber material and the positive electrode active material;

if the electronic conductor additive and/or the inorganic ion conductor additive exist, the electronic conductor additive and/or the inorganic ion conductor additive are dispersed in the solid positive electrode composite material;

The addition of the anode active material can enhance the dissociation of electrolyte salt, increase the free volume of an organic phase, reduce the crystallinity, and interact with an organic fiber material to form more interface ion transport channels, thereby further improving the ionic conductivity of the solid anode composite material.

The embodiment of the invention also provides a solid positive electrode which comprises a positive electrode current collector, wherein the solid positive electrode composite material is covered on the positive electrode current collector.

The embodiment of the invention also provides a preparation method of the solid-state anode composite material, which comprises the following steps:

spraying a polymer solution onto a selected receiving surface by adopting an electrostatic spinning technology to form a continuous two-dimensional or three-dimensional structure, wherein the organic fiber material at least has an ion conductor function;

spraying a dispersion liquid of a positive electrode active material or a mixed dispersion liquid of the positive electrode active material and an electronic conductor additive and/or an inorganic ion conductor additive onto the selected receiving surface by adopting an electrostatic spraying technology while spraying the polymer solution, then carrying out pressurization treatment on the obtained composite material to densify the composite material so as to distribute the positive electrode active material in holes contained in a continuous organic phase, and then impregnating the composite material with an electrolyte salt solution so as to enable the electrolyte salt to enter the organic fiber material in the composite material and holes contained in a network structure formed by the organic fiber material and the positive electrode active material to form the solid positive electrode composite material;

In the embodiment of the invention, the organic fiber material can form a compact continuous organic phase through pressurization treatment, and then the electrolyte salt is added, so that the ionic conductivity of the solid-state positive electrode composite material can be further greatly improved while the dosage proportion of the electrolyte salt is greatly reduced.

The embodiment of the invention also provides a preparation method of the solid-state anode, which comprises the following steps: and preparing the solid positive electrode composite material according to the method, and uniformly covering the solid positive electrode composite material on a positive electrode current collector to obtain the solid positive electrode.

The embodiment of the invention also provides application of the solid-state positive electrode composite material or the solid-state positive electrode in preparation of an electrochemical device.

Compared with the prior art, the invention has the advantages that:

1) the solid-state anode composite material provided by the invention has the advantages of high ionic conductivity, excellent electrochemical performance, high mechanical property, good processability and the like, and has wide application prospect;

2) the solid-state anode composite material provided by the invention has a simple preparation process, does not contain a binder and a complex coating process which are included in the traditional anode pole piece, can improve the mass specific capacity and the volume specific capacity of the anode, can be integrally prepared with the cathode and the diaphragm, and improves the interface compatibility and the stability between electrode electrolytes; meanwhile, the preparation method can be used for batch preparation, the cost of used raw materials is low, the conditions are mild, expensive production equipment is not needed, the yield is high, the controllability and the stability are good, and the large-scale batch preparation is easy to realize;

3) the preparation method of the solid-state anode composite material provided by the invention can be suitable for different battery systems, provides a good idea for the research and development of all-solid-state batteries, is not only suitable for the preparation of the anode film, but also suitable for the preparation of all inorganic material films, and has universal significance.

Drawings

FIG. 1 is a scanning electron micrograph of a prior art positive electrode material;

FIG. 2 is a schematic flow chart illustrating the preparation of a solid state positive electrode film according to an exemplary embodiment of the present invention;

FIG. 3 is a schematic diagram of a solid state positive electrode composite fabricated cell according to an exemplary embodiment of the present invention;

FIG. 4 is a scanning electron micrograph of a flexible solid positive electrode film prepared in example 1 of the present invention;

FIG. 5 is a photomicrograph of a flexible solid state positive film made in example 1 of the present invention;

FIG. 6 is a scanning electron microscope image of a flexible solid positive electrode thin film obtained after dropping a lithium salt in example 1 of the present invention;

FIG. 7 is a graph of the electrochemical cycling performance of the flexible solid state positive electrode film prepared in example 1 of the present invention;

FIG. 8 is a scanning electron micrograph of a flexible solid positive film prepared in example 2 of the present invention;

FIG. 9 is a graph showing the first charge and discharge when the flexible solid-state positive electrode film prepared in example 2 of the present invention is used as a positive electrode;

FIG. 10 is a scanning electron micrograph of a flexible solid positive film prepared in example 3 of the present invention;

fig. 11 is a charge and discharge curve of the flexible solid state positive electrode thin film prepared in example 3 of the present invention;

FIG. 12 is a scanning electron micrograph of a flexible solid positive film prepared in example 4 of the present invention;

fig. 13 is a scanning electron micrograph of a flexible solid positive electrode thin film prepared in comparative example 2 of the present invention.

Detailed Description

In view of the defects of the prior art, the inventor of the present invention has made extensive research and practice to propose the technical solution of the present invention, and further explains the technical solution, the implementation process and the principle, etc. as follows. It is to be understood, however, that within the scope of the present invention, each of the above-described features of the present invention and each of the features described in detail below (examples) may be combined with each other to form new or preferred embodiments. Not to be reiterated herein, but to the extent of space.

An aspect of an embodiment of the present invention provides a solid state positive electrode composite material, including:

In some embodiments of the invention, the organic fibrous material also functions as an electron conductor. Accordingly, the solid positive electrode composite material may include only the positive electrode active material, the organic fiber material, and the electrolyte salt.

In other embodiments of the present invention, although the organic fiber material also has the function of an electron conductor, the solid state positive electrode composite material may also include an electron conductor additive and/or an inorganic ion conductor additive, etc. to further improve the performance of the solid state positive electrode composite material. These electron conductor additives and/or inorganic ion conductor additives may be dispersed within the solid state positive electrode composite.

In some embodiments of the invention, the organic fibrous material has only the function of an ionic conductor. Accordingly, the solid positive electrode composite may include a positive electrode active material, an electron conductor additive, an organic fiber material, and an electrolyte salt. These electron conductor additives may be dispersed within the solid state positive electrode composite.

In some embodiments of the present invention, the organic fiber material has only the function of an ion conductor, and the solid-state positive electrode composite may include a positive electrode active material, an electron conductor additive, an inorganic ion conductor additive, an organic fiber material, and an electrolyte salt. The electronic conductor additive and the inorganic ion conductor additive can be dispersed in the solid positive electrode composite material.

In some preferred embodiments, the thickness of the solid positive electrode composite material is 30 to 500 μm, preferably 50 to 300 μm, and particularly preferably 150 to 250 μm.

Further, the ionic conductivity of the solid positive electrode composite material is 1.0x10^-4～1.0x10^-2S/cm。

Further onThe ionic conductivity of the solid positive electrode composite material at 25 ℃ is 1.0x10^-4～1.0x10^-2S/cm。

Further, the density of the solid-state positive electrode composite material is 1-5 g/cm³。

Furthermore, the bending strength of the solid-state positive electrode composite material is 1-20 MPa.

In some preferred embodiments, the mass ratio of the electrolyte salt to the organic fiber material in the solid state positive electrode composite material is 1: 2-1: 10, preferably 1: 3-1: 6.

further, the content of the electrolyte salt in the solid positive electrode composite material is 1-10 wt%, preferably 1-5 wt%.

Preferably, the electrolyte salt may be one or a combination of two or more of lithium salts such as lithium bistrifluoromethanesulfonimide (LiTFSI), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium hexafluorophosphate (LiPF6), and the like, and may also be a lithium salt of a small molecule polymer such as lithium succinonitrile bistrifluoromethanesulfonimide, but is not limited thereto. The electrolyte salt may be any electrolyte salt used in secondary metal batteries such as sodium salt, magnesium salt, and aluminum salt.

In some embodiments, the diameter of the organic fibrous material in the solid positive electrode composite is 50nm to 2 μm, preferably 100nm to 1 μm, more preferably 150nm to 800nm, and particularly preferably 300nm to 600 nm.

Further, the content of the organic fiber material in the solid-state positive electrode composite material is 5-60 wt%, preferably 10-20 wt%.

In some embodiments, the material of the organic fiber material includes a polymer, which has at least an ion conducting function.

Preferably, the polymer includes any one or a combination of two or more of Polyacrylonitrile (PAN), polyethylene oxide (pe), polyvinylpyrrolidone (PVP), polyethylene glycol (peg), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), and Polytetrafluoroethylene (PTFE), but is not limited thereto.

More preferably, the organic fiber material comprises a polymer which is formed by blending and grafting a conductive polymer and an ion-conducting polymer and has the functions of ionic and electronic conductors.

In some preferred embodiments, the content of the positive active material in the solid positive electrode composite material is 30 to 95 wt%, preferably 50 to 90 wt%, further preferably 60 to 80 wt%, and particularly preferably 70 to 80 wt%. In the invention, when the content of the positive electrode active material particles is more than 70 wt%, the solid positive electrode composite material still has good flexibility.

In some embodiments, the particle size of the inorganic cathode active material particles is 2nm to 20 μm, preferably 5nm to 1 μm, more preferably 10nm to 1 μm, and particularly preferably 20nm to 1 μm.

In some preferred embodiments, the material of the positive electrode active material may be any one or a precursor of an oxide positive electrode material, a sulfide positive electrode material, a polyanion positive electrode material, or the like, or may be all positive electrode materials and precursors thereof applicable to a secondary battery, such as a sodium ion battery positive electrode material, a magnesium ion battery positive electrode material, an aluminum ion battery positive electrode material, or the like.

Preferably, the material of the positive electrode active material includes lithium iron phosphate, lithium manganate, lithium cobaltate, lithium nickel cobalt manganese oxide (li (nicomn) O)₂) Any one or a combination of two or more of lithium manganate and lithium nickel manganate, but not limited thereto.

In some embodiments, the content of the electron conductor additive in the solid positive electrode composite material is 0 to 50 wt%, preferably 0 to 20 wt%, and more preferably 0 to 10 wt%.

Further, the electronic conductor additive includes any one or a combination of two or more of acetylene black, Super P conductive carbon black, ketjen black, carbon nanotubes, carbon fibers, and conductive graphite, but is not limited thereto.

In some embodiments, the content of the inorganic ion conductor additive in the solid positive electrode composite material is 0 to 70 wt%, preferably 0 to 40 wt%, and more preferably 0 to 20 wt%.

Further, the inorganic ionThe sub-conductor additive comprises a lithium ion conductor additive, a sodium ion conductor additive, a magnesium ion conductor additive or an aluminum ion conductor additive, wherein the lithium ion conductor additive comprises a NASICON type lithium ceramic electrolyte, a perovskite type lithium ceramic electrolyte, a garnet type lithium ceramic electrolyte, a LISICON type lithium ceramic electrolyte, Li₃N-type lithium ceramic electrolyte, lithiated BPO₄Lithium-conducting ceramic electrolyte and lithium ion battery using the same₄SiO₄The lithium ceramic electrolyte used as a precursor may be any one or a combination of two or more of Lithium Lanthanum Zirconium Tantalum Oxide (LLZTO), for example, but is not limited thereto.

The addition amount of the anode active material in the solid anode composite material can be more than 70 wt%, and the addition of the anode active material can enhance the dissociation of electrolyte salt, increase the free volume of an organic phase and reduce the crystallinity, thereby prolonging the cycle life of the lithium ion battery and improving the coulombic efficiency of the battery. Meanwhile, under the condition of adding the anode active material, the organic fiber material, the anode active material and the electrolyte salt in the solid anode composite material are cooperated with each other, so that the ionic conductivity of the solid anode composite material can be further improved, and the solid anode composite material shows good electrochemical performance in the application of a secondary battery.

Preferably, the solid positive electrode composite material is in the form of a flexible film.

One aspect of the embodiments of the present invention provides a solid-state positive electrode composite material, which is formed by subjecting a composite material to pressure treatment and then impregnating the composite material with an electrolyte salt solution;

the composite material comprises:

the cathode active material is distributed in holes contained in the continuous organic phase, and the electrolyte salt is distributed in the organic fiber material and in holes contained in a network structure formed by the organic fiber material and the cathode active material;

Further, the solid state positive electrode composite material has an ionic conductivity of 1.0x10 at 25 ℃^-4～1.0x10^-2S/cm。

Preferably, the material of the positive electrode active material includes iron phosphateLithium, lithium manganate, lithium cobaltate, lithium nickel cobalt manganese (Li (NiCoMn) O)₂) Any one or a combination of two or more of lithium manganate and lithium nickel manganate, but not limited thereto.

Further, the inorganic ion conductor additive comprises a lithium ion conductor additive, a sodium ion conductor additive, a magnesium ion conductor additive or an aluminum ion conductor additive, wherein the lithium ion conductor additive comprises a NASICON type lithium ceramic electrolyte, a perovskite type lithium ceramic electrolyte, a garnet type lithium ceramic electrolyte, a LISICON type lithium ceramic electrolyte, Li₃N-type lithium ceramic electrolyte, lithiated BPO₄Lithium-conducting ceramic electrolyte and lithium ion battery using the same₄SiO₄The lithium ceramic electrolyte used as a precursor may be any one or a combination of two or more of Lithium Lanthanum Zirconium Tantalum Oxide (LLZTO), for example, but is not limited thereto.

Preferably, in the electrostatic spinning technology, the distance between an electrostatic spinning liquid outlet and the receiving surface is 5-30 cm, and the electrostatic voltage is 5-50 KV.

Preferably, in the electrostatic spraying technology, the distance between an electrostatic spraying liquid outlet and the receiving surface is 5-30 cm, and the electrostatic voltage is 5-50 KV.

In some embodiments, the spray direction of the electrospinning liquid outlet and the spray direction of the electrostatic spraying liquid outlet form an angle greater than or equal to 0 and less than 90 °.

Preferably, the flow ratio of the polymer solution to the dispersion liquid of the positive electrode active material or the mixed dispersion liquid is 100: 1-1: 100, preferably 1: 10-1: 50, particularly preferably 1: 5-1: 7. the invention can prepare flexible films with different anode material contents by controlling the flow rate ratio of spinning and spraying.

Further, the pressure of the pressurization treatment is 100 KPa-20 MPa, the time is 1-60 minutes, preferably 1-10 minutes, and the temperature is 25-60 ℃.

Further, the dipping time is 1 minute to 24 hours, preferably 5 minutes to 10 minutes.

Preferably, the solid positive electrode composite material is film-shaped, and particularly preferably is flexible film-shaped.

In summary, the addition of the organic fiber material in the solid-state positive electrode composite material of the present invention imparts the characteristic of flexibility to the positive electrode material, can be made very thin (10-20 microns) and still maintain good integrity and processability. The inorganic material can effectively inhibit the growth of lithium dendrites and the like in energy storage equipment such as a lithium ion battery and the like, so that the cycle life of the equipment is prolonged, and the coulomb efficiency of the battery is improved.

The solid-state anode composite material provided by the invention has the following performance characteristics: 1) the ionic conductivity is high (meeting the application requirement of an electrochemical device); 2) the material has special mechanical properties, can still maintain mechanical integrity under the condition of being made into a very thin film, is not broken when being bent, and has good processability; 3) exhibit good electrochemical performance in secondary battery applications.

Preferably, the positive electrode current collector includes any one of aluminum foil, carbon-coated aluminum foil, carbon felt, and carbon paper, but is not limited thereto.

Further, the solid-state anode composite material is uniformly coated on the surface of the anode current collector, the thickness of the solid-state anode composite material is 30-500 micrometers, preferably 50-300 micrometers, further preferably 150-250 micrometers, and the ionic conductivity is 1.0x10 at 25 DEG C^-4～1.0x10^-2S/cm。

Referring to fig. 2, another aspect of the embodiment of the present invention further provides a method for preparing a solid positive electrode composite material, including:

using an electrostatic spinning technology to spray a polymer solution (which can be called as solution 1) onto a selected receiving surface to form a continuous two-dimensional or three-dimensional structure, wherein the organic fiber material at least has an ion conductor function;

spraying a dispersion liquid of a positive electrode active material or a mixed dispersion liquid (which can be called as a solution 2) of the positive electrode active material and an electronic conductor additive and/or an inorganic ion conductor additive onto the selected receiving surface by adopting an electrostatic spraying technology while spraying the polymer solution, then pressurizing the obtained composite material to densify the composite material so that the positive electrode active material is distributed in holes contained in a continuous organic phase, and then soaking the composite material by an electrolyte salt solution so that an electrolyte salt enters the inside of an organic fiber material in the composite material and holes contained in a network structure formed by the organic fiber material and the positive electrode active material to form the solid positive electrode composite material;

In the foregoing embodiment, the organic fiber material is pressurized to form a dense continuous organic phase, and then the electrolyte salt is added, so that the ionic conductivity of the organic polymer solid-state positive electrode composite material can be further greatly improved while the dosage proportion of the electrolyte salt is greatly reduced.

Preferably, the solid state positive electrode composite is in the form of a film, preferably a flexible film.

As one of the preferred embodiments, the preparation method comprises: an electrospinning liquid outlet for ejecting the polymer solution and an electrostatic spraying liquid outlet for ejecting the dispersion liquid of the positive electrode active material or the mixed dispersion liquid are arranged in parallel in a side-by-side manner.

As one of the preferred embodiments, the preparation method comprises: and enabling the spraying direction of the electrostatic spinning liquid outlet and the spraying direction of the electrostatic spraying liquid outlet to form an included angle which is more than or equal to 0 and less than 90 degrees.

As a preferred embodiment, the shape of the electrospinning exit orifice and/or the electrostatic spraying exit orifice comprises a circular shape or a slit shape, preferably a slit shape, wherein the slit shape has a high throughput. The liquid outlet with the slit structure can make the polymer solution sprayed on the receiving surface and the dispersion liquid of the positive electrode active material or the mixed dispersion liquid more uniformly distributed.

As one of the preferred embodiments, the dispersion liquid of the cathode active material or the mixed dispersion liquid further contains a surfactant to prevent the cathode active material from settling in the dispersion liquid, which may cause blockage of the electrostatic spray outlet and uneven spraying, thereby affecting the uniformity and performance of the formed solid cathode film.

Preferably, the content of the surfactant in the dispersion liquid of the positive electrode active material or the mixed dispersion liquid is 0.1 to 1 wt%.

Preferably, the surfactant can be selected from ionic surfactants such as cationic surfactants, anionic surfactants, etc., nonionic surfactants, amphoteric surfactants, built surfactants, other surfactants, etc., but is not limited thereto.

As one of the preferred embodiments, the preparation method further comprises: and applying an external electric field between the receiving surface and the electrostatic spinning liquid outlet and/or the electrostatic spraying liquid outlet, and spraying the polymer solution onto the receiving surface by adopting an electrostatic spinning technology under the action of the external electric field, and spraying the dispersion liquid or the mixed dispersion liquid of the positive electrode active material onto the receiving surface by adopting the electrostatic spraying technology.

In some embodiments, the receiving surface is a surface of a receiving device.

Preferably, the receiving device includes any one or a combination of two or more of a roller receiving device, a plane receiving device and an aqueous solution receiving device, but is not limited thereto.

In some embodiments, the receiving surface is further provided with negative charge generating means.

Further, when the polymer solution and the dispersion liquid of the positive electrode active material or the mixed dispersion liquid are sprayed toward the receiving surface, the electrospinning liquid outlet and the electrostatic spraying liquid outlet are relatively moved with respect to the receiving surface in the axial direction of the receiving device.

Further, when the polymer solution and the dispersion liquid of the positive electrode active material or the mixed dispersion liquid are ejected toward the receiving surface, the electrospinning liquid outlet and the electrostatic spraying liquid outlet perform reciprocating relative movement with respect to the receiving surface in the longitudinal direction or the width direction of the receiving surface.

Furthermore, the receiving surface, the electrostatic spinning liquid outlet and the electrostatic spraying liquid outlet are arranged at a set angle.

Further, the set angle includes 0 to 89.9 °.

In some embodiments, the drum is maintained in a rotating state while the polymer solution and the dispersion of the positive active material or the mixed dispersion are sprayed to the surface of the drum receiving device. Maintaining the above working state for a period of time to obtain a film, and easily peeling the obtained product off the roller.

Furthermore, the rotating speed of the roller receiving device is 300-1000 rpm.

In some embodiments, when the polymer solution and the dispersion liquid of the positive electrode active material or the mixed dispersion liquid are ejected toward the receiving surface, the flow ratio of the polymer solution to the dispersion liquid of the positive electrode active material or the mixed dispersion liquid is 100: 1-1: 100, preferably 1: 10-1: 50, particularly preferably 1: 5-1: and 7, flexible films with different contents of the cathode material can be prepared by controlling the flow rate ratio of spinning and spraying.

Preferably, the distance between the electrostatic spinning liquid outlet and the receiving surface and the distance between the electrostatic spraying liquid outlet and the receiving surface are 5-30 cm.

Preferably, the electrostatic voltage adopted by the electrostatic spinning technology and the electrostatic spraying technology is 5-50 KV.

As one of the preferred embodiments, the preparation method comprises: and placing the film collected from the receiving surface on a roller press for repeated rolling under the pressure of 100 KPa-20 MPa.

As one of the preferred embodiments, the preparation method further comprises: and soaking the solid positive electrode composite material with an electrolyte salt solution for 1-24 hours, preferably 5-10 minutes, and then drying.

Further, the electrolyte salt may be a lithium salt, such as lithium bistrifluoromethanesulfonylimide (LiTFSI), lithium perchlorate (LiClO)₄) Lithium hexafluoroarsenate (LiAsF)₆) Lithium hexafluorophosphate (LiPF)₆) And the like, and also lithium salts of small-molecule polymers, such as, but not limited to, succinonitrile-lithium bistrifluoromethanesulfonylimide. The electrolyte salt may be any electrolyte salt used in secondary metal batteries such as sodium salt, magnesium salt, and aluminum salt.

In some embodiments, the method of making comprises: dissolving a polymer in a first solvent to obtain the polymer solution.

The first solvent includes, but is not limited to, all liquids that can dissolve the aforementioned polymer, such as water, all alcoholic liquids such as N-methylpyrrolidone and ethanol, and any one or a combination of two or more of N, N-dimethylformamide, dimethyl sulfoxide and dimethylacetamide.

In some embodiments, the method of making comprises: uniformly dispersing a positive electrode active material in a second solvent to obtain a dispersion liquid of the positive electrode active material;

or, uniformly dispersing the positive electrode active material and the electron conductor additive and/or the inorganic ion conductor additive in a second solvent to obtain the mixed dispersion liquid.

In some preferred embodiments, the material of the inorganic cathode active material particles may be any one or a precursor of an oxide cathode material, a sulfide cathode material, a polyanion cathode material, or the like, or may be all cathode materials and precursors thereof applicable to secondary batteries, such as a sodium ion battery cathode material, a magnesium ion battery cathode material, an aluminum ion battery cathode material, or the like.

Preferably, the material of the positive electrode active material includes lithium iron phosphate, lithium manganate, lithium cobaltate, lithium nickel cobalt manganese oxide (li (nicomn) O)₂) Any one or more of lithium manganate and nickel lithium manganateA combination of two or more, but not limited thereto.

Further, the inorganic ion conductor additive comprises a lithium ion conductor additive, a sodium ion conductor additive, a magnesium ion conductor additive or an aluminum ion conductor additive, wherein the lithium ion conductor additive comprises a NASICON type lithium ceramic electrolyte, a perovskite type lithium ceramic electrolyte, a garnet type lithium ceramic electrolyte, a LISICON type lithium ceramic electrolyte, Li₃N-type lithium ceramic electrolyte, lithiated BPO₄Lithium-conducting ceramic electrolyte and lithium ion battery using the same₄SiO₄Any one or a combination of two or more of lithium ceramic electrolytes as a precursor, but not limited thereto.

Preferably, the second solvent may be any liquid in which the positive electrode active material, the electron conductor additive, and the inorganic ion conductor additive are dispersed, and may be any one or a combination of two or more of water, an alcohol liquid such as ethanol and isopropyl alcohol, and another ketone liquid such as acetone, but is not limited thereto.

By the technical scheme, the solid-state anode composite material disclosed by the invention is simple in preparation process, can be prepared in batches, is low in cost of used raw materials, mild in condition, high in yield, adjustable and controllable, good in repeatability and stability, can be suitable for different battery systems, provides a good idea for research and development of all-solid-state batteries, is not only suitable for preparation of an anode film, but also suitable for preparation of all inorganic material films, and has universal significance.

In addition, as the spun fiber has good flexibility, the film prepared by the method also has flexibility, and the flexible films with different contents of the positive active materials can be prepared by controlling the flow rate ratio of the spinning to the spraying. The system can realize the preparation of the flexible solid-state anode film by utilizing the characteristics of easy process and easy control of the preparation process.

Another aspect of the embodiments of the present invention also provides a method for preparing a solid positive electrode, including: and preparing the solid positive electrode composite material according to the method, and uniformly covering the solid positive electrode composite material on a positive electrode current collector to obtain the solid positive electrode.

In another aspect of the embodiments of the present invention, there is also provided a use of the aforementioned solid positive electrode composite material or solid positive electrode in the preparation of an electrochemical device.

Preferably, the electrochemical device comprises an energy storage device comprising a battery and/or an electrochromic device.

Further, the electrochromic device includes a black-and-white electronic book, a color electronic book, and the like.

For example, the embodiment of the invention also provides a battery, which comprises a positive electrode, a negative electrode and an electrolyte, wherein the positive electrode comprises the solid positive electrode composite material.

Further, the battery may be an all-solid-state battery.

Further, a sandwich-structured symmetrical battery is formed by using the solid positive electrode composite material or the solid positive electrode thin film as a working electrode, a common secondary battery electrolyte as an electrolyte, and a common secondary battery negative electrode material (metal, oxide, carbon material, etc.) as a counter electrode, as shown in fig. 3. The battery may be a lithium battery, a sodium battery, a magnesium battery, an aluminum battery, etc., depending on the selected metal electrode, but is not limited thereto.

The technical scheme of the invention is further explained in detail by a plurality of embodiments and the accompanying drawings. However, the examples are chosen only for the purpose of illustrating the invention and are not to be construed as limiting the scope of the invention.

Example 1

About 1g of commercially available polyvinylidene fluoride (PVDF) powder was dissolved in about 10g of N, N-Dimethylformamide (DMF) to obtain a polyvinylidene fluoride solution. About 1g of commercially available lithium iron phosphate powder having a particle size of about 700nm and 0.14g of commercially available acetylene black were added to about 20g of ethanol containing about 1% by weight of a surfactant andstirring and dispersing to obtain a mixed dispersion liquid of the positive electrode active material and the acetylene black. Spinning and spraying are simultaneously carried out under the high pressure of about 20KV, the distance between two needles and a roller receiving device is about 8cm, the flow rate of polyvinylidene fluoride solution in the spinning needle is about 10 mu l/min, and the flow rate of positive active material dispersion liquid in the spraying needle is about 80 mu l/min, so that after about 8 hours of operation, a flexible positive film can be taken off from the roller receiving device, and then rolling is carried out at about 100KPa for about 60 minutes, thus obtaining a flexible solid positive film with the thickness of 80 mu m, wherein the ionic conductivity of the flexible solid positive film is 1.0x10^-2S/cm, density of 2.5g/cm³Wherein the content of the positive electrode active material is up to about 70 wt%. A scanning electron micrograph of the flexible solid positive electrode film prepared by this example is shown in fig. 4, and a macro photograph thereof is shown in fig. 5. In addition, succinonitrile-5 wt% lithium bis (trifluoromethanesulfonyl) imide (SN-5 wt% LITFSI) is heated and melted and then dropped into the flexible positive electrode film, so that the mass ratio of the electrolyte salt to the organic fiber material in the solid positive electrode composite material is 1: and 6, a scanning electron microscope image of the flexible solid-state positive electrode film is shown in FIG. 6, and the flexible solid-state positive electrode film added with SN-5 wt% of LITFSI after the flexible solid-state positive electrode film is applied to an all-solid-state lithium battery also shows good electrochemical performance, and the cycle performance of the flexible solid-state positive electrode film is shown in FIG. 7.

Example 2

About 1g of commercially available Polytetrafluoroethylene (PTFE) was dissolved in about 10g of N-methylpyrrolidone to obtain a polytetrafluoroethylene solution. About 0.8g of commercially available lithium iron phosphate powder having a particle size of about 700nm, about 0.14g of commercially available ketjen black having a particle size of about 30 to 45nm, and about 0.2g of lithium ion fast conductor Lithium Lanthanum Zirconium Tantalum Oxide (LLZTO) having a particle size of about 300 to 450nm were added to about 20g of ethanol containing about 1wt% of a surfactant and stirred and dispersed to obtain a mixed dispersion. Spinning and spraying are simultaneously carried out under the high pressure of about 15KV, the distance between two needles and a roller receiving device is about 5cm, the flow rate of polytetrafluoroethylene solution in the spinning needle is about 10 mu l/min, and the flow rate of mixed dispersion liquid in the spraying needle is about 100 mu l/min, so that after working for about 8 hours, a flexible solid anode film can be taken off from the roller receiving device, and the film is rolled under the pressure of about 1MPa for about 1 minute, and then the thickness of the film is increasedThe degree is 100 mu m, and then the lithium perchlorate/ethanol solution is soaked for 24 minutes and dried, so that the mass ratio of the electrolyte salt to the organic fiber material in the solid positive electrode composite material is 1: 3, preparing the flexible solid anode film with the ionic conductivity of 1.0x10^-3S/cm, density of 2.8g/cm³Wherein the content of the lithium iron phosphate positive active material reaches about 80 wt%. A scanning electron micrograph of the flexible solid positive electrode film prepared by this example is shown in fig. 8, and its first charge-discharge curve is shown in fig. 9.

Example 3

About 1g of commercially available Polyacrylonitrile (PAN) powder was dissolved in about 10g of N, N-Dimethylformamide (DMF) to obtain a polyacrylonitrile solution. About 1g of lithium nickel manganese oxide (LiNi)_0.5Mn_0.5O₂) The powder and 0.14g of commercially available ketjen black were added to about 20g of ethanol containing about 1% by weight of a surfactant and dispersed with stirring to obtain a mixed dispersion. Spinning and spraying are carried out simultaneously in a side-by-side parallel mode under the high pressure of about 15KV, the distance between two needles and a roller receiving device is about 15cm, the flow rate of polyacrylonitrile solution in a spinning needle is about 10 mu l/min, and the flow rate of mixed dispersion liquid in a spraying needle is about 70 mu l/min, so that after about 16 hours of operation, a flexible solid anode film can be pulled off from the roller receiving device, rolling is carried out at about 1MPa for about 1 minute, the thickness is 250 mu m, and then soaking is carried out in lithium perchlorate/ethanol solution for 1 minute and drying is carried out, so that the mass ratio of electrolyte salt and organic fiber material in the solid anode composite material is 1: 5, preparing the flexible solid anode film with the ionic conductivity of 1.0x10^-4S/cm, density 3.8g/cm³Wherein the lithium nickel manganese oxide content is about 85 wt%. A scanning electron micrograph of the flexible solid positive electrode film prepared by this example is shown in fig. 10, and its first charge-discharge curve is shown in fig. 11.

Example 4

About 0.4g of commercially available polyvinylidene fluoride (PVDF) powder was dissolved in about 10g of N-methylpyrrolidone to obtain a polyvinylidene fluoride solution. About 1g of commercially available lithium nickel cobalt manganese oxide Li (NiCoMn) O having a particle size of about 5 μm₂A powder and about 0.15g of commercially available, particle size of aboutAdding 30-45 nm acetylene black into about 20g of acetone containing about 0.1 wt% of a surfactant, and stirring and dispersing to obtain a mixed dispersion liquid. Spinning and spraying are simultaneously carried out under the high pressure of about 50KV, the distance between two needles and a roller receiving device is about 20cm, the flow rate of a polyvinylidene fluoride solution in the spinning needle is about 200 mu l/min, and the flow rate of a mixed dispersion liquid in the spraying needle is about 2 mu l/min, so that after about 15 hours of operation, a flexible solid-state anode film can be uncovered from the roller receiving device, and then rolling is carried out under about 10MPa for about 5 minutes to obtain the flexible solid-state anode film with the thickness of 200 mu m, wherein the content of inorganic anode active material particles, namely nickel cobalt lithium manganate, reaches about 95 wt%. In addition, 1mol/L lithium bis (trifluoromethylsulfonyl) imide-ethanol solution is dripped into the flexible positive electrode film and dried, so that the mass ratio of the electrolyte salt to the organic fiber material in the solid positive electrode composite material is 1: 4, its ionic conductivity was 1.0x10^-4S/cm, density 4.3g/cm³The scanning electron microscope image thereof is shown in fig. 12.

Example 5

About 1g of commercially available Polyacrylonitrile (PAN) powder was dissolved in about 10g of dimethyl sulfoxide to obtain a polyacrylonitrile solution. About 2g of commercially available lithium manganate powder having a particle size of about 700nm was added to about 20g of isopropyl alcohol and dispersed with stirring to obtain a lithium manganate dispersion. Spinning and spraying are carried out simultaneously in a side-by-side parallel mode under the high pressure of about 5KV, the distance between two needles and a roller receiving device is about 5cm, the flow rate of polyacrylonitrile solution in a spinning needle is about 10 mu l/min, and the flow rate of lithium manganese oxide dispersion liquid in a spraying needle is about 500 mu l/min, so that after about 30 hours of operation, a flexible solid positive electrode film can be pulled off from the roller receiving device, the thickness of the film is 300 mu m after rolling is carried out for about 1 minute under the pressure of about 20MPa, and then the film is soaked in a lithium salt solution for 10 minutes and dried, so that the mass ratio of electrolyte salt and organic fiber material in the solid positive electrode composite material is 1: 3, preparing the flexible solid anode film with the ionic conductivity of 1.0x10^-4S/cm, density of 2.5g/cm³Wherein the amount of lithium manganate is about 60 wt%.

Example 6

About 1g of commercially available polymethyl methacrylate (PMMA) was dissolved in about 10g of acetonitrile to obtain a polymethyl methacrylate solution. About 1g of a commercially available lithium cobaltate powder having a particle size of about 700nm and about 0.14g of a commercially available acetylene black having a particle size of about 30 to 45nm were added to about 20g of water and dispersed with stirring to obtain a mixed dispersion. Spinning and spraying are simultaneously carried out under the high pressure of about 25KV, the distance between two needles and a roller receiving device is about 30cm, the flow rate of the polymethyl methacrylate solution in the spinning needle is about 10 mu l/min, and the flow rate of the mixed dispersion liquid in the spraying needle is about 30 mu l/min, so that after about 10 hours of operation, a flexible solid positive electrode film is stripped from the roller receiving device, then rolling is carried out at about 100KPa for about 60 minutes, the thickness is 30 mu m, then soaking is carried out in the lithium perchlorate/ethanol solution for 24 hours, and drying is carried out, so that the mass ratio of electrolyte salt and organic fiber material in the solid positive electrode composite material is 1: 5, preparing the flexible solid anode film with the ionic conductivity of 1.0x10^-4S/cm, density 1.9g/cm³Wherein the content of the positive electrode active material is up to about 30 wt%.

Example 7

About 1g of commercially available Polyacrylonitrile (PAN) powder was dissolved in about 10g of N, N-Dimethylformamide (DMF) to obtain a polyacrylonitrile solution. About 1g of commercially available sodium cobaltate (Na) with a particle size of about 700nm was added_0.5CoO₂) And was not added to about 20g of ethanol containing about 1% by weight of a surfactant and dispersed with stirring to obtain a dispersion liquid of a positive electrode active material. Spinning and spraying are carried out simultaneously under the high pressure of about 15KV, the distance between two needles and a roller receiving device is about 6cm, the flow rate of polyacrylonitrile solution in a spinning needle is about 2 mul/min, and the flow rate of dispersion liquid of a positive active material in a spraying needle is about 200 mul/min, so that after about 8 hours of operation, a flexible film can be taken off from the roller receiving device, then rolling is carried out for about 5 minutes under about 5MPa, a flexible solid positive film with the thickness of 500 mu M can be prepared, wherein the content of the positive active material reaches about 50 wt%, then a proper amount of 0.5M sodium perchlorate-ethanol solution is dripped into the flexible positive film, and the ethanol solution is removed under the vacuum heating state, so that the solid is obtainedThe mass ratio of the electrolyte salt to the organic fiber material in the state positive electrode composite material is 1: 10, obtaining the flexible solid anode film with the ionic conductivity of 1.0x10^-4S/cm, density of 2.6g/cm³。

Comparative example 1 (Positive electrode suspension without dispersant)

About 1g of commercially available Polyacrylonitrile (PAN) powder was dissolved in about 10g of N, N-Dimethylformamide (DMF) to obtain a polyacrylonitrile solution. About 1gNa_0.5CoO₂Adding to about 20g of ethanol and stirring to disperse to obtain Na_0.5CoO₂And (3) dispersing the mixture. Spinning and spraying are carried out simultaneously in a side-by-side parallel mode under the high pressure of about 25KV, the distance between the two needles and the roller receiving device is about 10cm, the flow rate of polyacrylonitrile solution in the spinning needle is about 10 mul/min, and Na in the spraying needle_0.5CoO₂The dispersion flow rate was about 70. mu.l/min, and after about 8 hours of operation, a sheet of flexible Na was removed from the roll receiver_0.5CoO₂Film of Na therein_0.5CoO₂Is about 75 wt%. However, the uniformity of the film was poor, and there was particle agglomeration or no particle phenomenon in many places.

Comparative example 2 (side by side with vertical to each other)

About 1g of commercially available polyvinylidene fluoride (PVDF) powder was dissolved in about 10g of N, N-Dimethylformamide (DMF) to obtain a polyvinylidene fluoride solution. About 1g of commercially available lithium nickel manganese oxide having a particle size of about 0.5 μm was added to about 20g of ethanol containing about 0.1% by weight of a surfactant and dispersed with stirring to obtain a lithium nickel manganese oxide dispersion. Spinning and spraying are simultaneously carried out by two spray heads in a mutually perpendicular mode under the high pressure of about 25KV, the distance between the two spray heads and the roller receiving device is about 10cm, the flow rate of the polyvinylidene fluoride solution in the spinning spray heads is about 10 mu l/min, and the flow rate of the lithium nickel manganese oxide dispersion liquid in the spraying needle head is about 70 mu l/min, so that after about 10 hours of operation, a flexible anode film can be pulled off from the roller receiving device, wherein the content of the lithium nickel manganese oxide is 60 wt%, and the uniformity is poor. A scanning electron micrograph of the flexible positive electrode film prepared by the present comparative example is shown in fig. 13.

Comparative example 3 (spinning together after compounding Polymer and Positive electrode active Material)

In the prior art, 1g of commercially available polyvinylidene fluoride (PVDF) powder and 1g of commercially available lithium nickel manganese oxide powder with a particle size of about 0.5 micron are dispersed in N, N-Dimethylformamide (DMF), the mixture is stirred uniformly for a long time, the uniformly mixed solution is spun at a high pressure of about 15KV, the distance between a nozzle and a roller receiving device is about 8cm, the flow rate of the positive electrode mixed solution in the spinning nozzle is about 15 μ l/min, after about 20 hours of operation, a film can be taken off from the roller receiving device, and then the film is rolled at about 1000KPa for about 10 minutes, so that the porosity of the obtained film is high, and the solid content of inorganic particles is about 50%.

Comparative example 4 (knife coating)

In the prior art, 1g of commercially available polyvinylidene fluoride (PVDF) powder and 1g of commercially available lithium nickel manganese oxide powder with the particle size of about 0.5 micron are dispersed in N, N-Dimethylformamide (DMF), the mixture is uniformly stirred for a long time, and then a blade coating or tape casting method is selected to prepare the positive electrode film, but the positive electrode material of the positive electrode film prepared by the method is not uniformly dispersed and the electric conductivity of a pole piece is lower.

Through examples 1-7 and comparative examples 1-4, it can be seen that the flexible solid-state positive electrode thin film obtained by the above technical scheme of the present invention has high ionic conductivity (meeting the application requirements of electrochemical devices), and simultaneously has special mechanical properties, no fracture during bending, good processability, and good electrochemical properties in secondary battery applications.

In addition, the inventors have also conducted experiments with other raw materials and conditions and the like listed in the present specification by referring to the manner of example 1 to example 7, and also produced a flexible solid positive electrode thin film having high ionic conductivity and excellent mechanical properties and electrochemical properties.

It should be understood that the above-mentioned embodiments are merely illustrative of the technical concepts and features of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a solid positive electrode composite material, characterized by comprising:

spraying a polymer solution onto a selected receiving surface by adopting an electrostatic spinning technology to form a continuous two-dimensional or three-dimensional structure to obtain a continuous organic phase which is formed by aggregating organic fiber materials at least having the function of an ion conductor;

spraying a dispersion liquid of a positive electrode active material or a mixed dispersion liquid of the positive electrode active material and an electronic conductor additive and/or an inorganic ion conductor additive onto the selected receiving surface by adopting an electrostatic spraying technology while spraying the polymer solution, then carrying out pressurization treatment on the obtained composite material to densify the composite material so as to distribute the positive electrode active material in holes contained in the continuous organic phase, and then impregnating the composite material with an electrolyte salt solution so as to enable the electrolyte salt to enter the organic fiber material in the composite material and holes contained in a network structure formed by the organic fiber material and the positive electrode active material to form the solid positive electrode composite material;

2. The production method according to claim 1, characterized by comprising: an electrospinning liquid outlet for ejecting the polymer solution and an electrostatic spraying liquid outlet for ejecting the dispersion liquid of the positive electrode active material or the mixed dispersion liquid are arranged in parallel in a side-by-side manner.

3. The production method according to claim 2, characterized by comprising: and enabling the spraying direction of the electrostatic spinning liquid outlet and the spraying direction of the electrostatic spraying liquid outlet to form an included angle which is more than or equal to 0 and less than 90 degrees.

4. The production method according to claim 2 or 3, characterized in that: the shapes of the electrostatic spinning liquid outlet and/or the electrostatic spraying liquid outlet comprise a circular shape or a slit shape.

5. The method of claim 1, wherein: the dispersion liquid of the positive electrode active material or the mixed dispersion liquid further contains a surfactant.

6. The method of claim 5, wherein: the content of the surfactant in the dispersion liquid of the positive electrode active material or the mixed dispersion liquid is 0.1-1 wt%.

7. The method of claim 5, wherein: the surfactant comprises any one or the combination of more than two of ionic surfactant, nonionic surfactant, amphoteric surfactant and compound surfactant.

8. The method of claim 7, wherein: the ionic surfactant comprises a cationic surfactant and/or an anionic surfactant.

9. The method of claim 2, further comprising: and an external electric field is applied between the receiving surface and the electrostatic spinning liquid outlet and/or the electrostatic spraying liquid outlet.

10. The method of claim 2, wherein: the receiving surface is a surface of a receiving device.

11. The method of manufacturing according to claim 10, wherein: the receiving device comprises any one or the combination of more than two of a roller receiving device, a plane receiving device and an aqueous solution receiving device.

12. The method of manufacturing according to claim 10, wherein: the receiving surface is provided with a negative charge generating device.

13. The method of manufacturing according to claim 10, wherein: when the polymer solution and the dispersion liquid of the positive electrode active material or the mixed dispersion liquid are sprayed to the receiving surface, the electrospinning liquid outlet and the electrostatic spraying liquid outlet are relatively moved with respect to the receiving surface in the axial direction of the receiving device.

14. The method of claim 2, wherein: when the polymer solution and the dispersion liquid of the positive electrode active material or the mixed dispersion liquid are jetted toward the receiving surface, the electrospinning liquid outlet and the electrostatic spraying liquid outlet perform reciprocating relative movement with the receiving surface along the length direction or the width direction of the receiving surface.

15. The method of claim 11, wherein: the drum is maintained in a rotating state while the polymer solution and the dispersion of the positive electrode active material or the mixed dispersion are sprayed to the surface of the drum receiving device.

16. The method of claim 15, wherein: the rotating speed of the roller receiving device is 300-1000 rpm.

17. The method of claim 1, wherein: when the polymer solution and the dispersion liquid or the mixed dispersion liquid of the positive electrode active material are ejected toward the receiving surface, the flow ratio of the polymer solution to the dispersion liquid or the mixed dispersion liquid of the positive electrode active material is 100: 1-1: 100.

18. the method of claim 17, wherein: when the polymer solution and the dispersion liquid or the mixed dispersion liquid of the positive electrode active material are ejected toward the receiving surface, the flow ratio of the polymer solution to the dispersion liquid or the mixed dispersion liquid of the positive electrode active material is 1: 10-1: 50.

19. the method of claim 18, wherein: when the polymer solution and the dispersion liquid or the mixed dispersion liquid of the positive electrode active material are ejected toward the receiving surface, the flow ratio of the polymer solution to the dispersion liquid or the mixed dispersion liquid of the positive electrode active material is 1: 3-1: 7.

20. the method of claim 2, wherein: and the distance between the electrostatic spinning liquid outlet and the receiving surface and the distance between the electrostatic spraying liquid outlet and the receiving surface are 5-30 cm.

21. The method of claim 2, wherein: the electrostatic spinning technology and the electrostatic spraying technology adopt electrostatic voltage of 5-50 KV.

22. The method of claim 1, wherein: the pressure of the pressurization treatment is 100 KPa-20 MPa, the time is 1-60 minutes, and the temperature is 25-60 ℃.

23. The method of claim 22, wherein: the time of the pressurization treatment is 1-10 minutes.

24. The method of claim 1, wherein: the dipping time is 1 minute to 24 hours.

25. The method of claim 24, wherein: the dipping time is 5-10 minutes.

26. The method of claim 1, wherein: the electrolyte salt includes a lithium salt, a sodium salt, a magnesium salt, or an aluminum salt.

27. The method of claim 26, wherein: the lithium salt comprises any one or the combination of more than two of lithium bis (trifluoromethane sulfonyl) imide, lithium perchlorate, lithium hexafluoroarsenate, lithium hexafluorophosphate and lithium succinonitrile-bis (trifluoromethane sulfonyl) imide.

28. The production method according to claim 1, characterized by comprising: dissolving a polymer in a first solvent to obtain the polymer solution.

29. The method of claim 28, wherein: the polymer comprises any one or the combination of more than two of polyacrylonitrile, polyethylene oxide, polyvinylpyrrolidone, polyethylene glycol, polymethyl methacrylate, polyvinylidene fluoride and polytetrafluoroethylene.

30. The method of claim 28, wherein: the polymer comprises a polymer which is formed by blending and grafting a conductive polymer and an ion-conducting polymer and has the functions of ionic and electronic conductors.

31. The method of claim 28, wherein: the first solvent comprises one or the combination of more than two of water, N-methyl pyrrolidone, alcohol, N-dimethylformamide, dimethyl sulfoxide and dimethylacetamide.

32. The method of claim 31, wherein: the alcohol comprises ethanol.

33. The production method according to claim 1, characterized by comprising: uniformly dispersing a positive electrode active material in a second solvent to obtain a dispersion liquid of the positive electrode active material;

34. The method of claim 33, wherein: the material of the positive electrode active material comprises any one or a precursor of any one of an oxide positive electrode material, a sulfide positive electrode material and a polyanion positive electrode material and/or any one or a precursor of any one of a sodium ion battery positive electrode material, a magnesium ion battery positive electrode material and an aluminum ion battery positive electrode material.

35. The method of claim 34, wherein: the material of the positive active material comprises any one or the combination of more than two of lithium iron phosphate, lithium manganate, lithium cobaltate and lithium nickel manganese oxide.

36. The method of claim 33, wherein: the electronic conductor additive comprises any one or the combination of more than two of acetylene black, Super P conductive carbon black, Ketjen black, carbon nano tubes, carbon fibers and conductive graphite.

37. The method of claim 33, wherein: the inorganic ion conductor additive comprises a lithium ion conductor additive, a sodium ion conductor additive, a magnesium ion conductor additive or an aluminum ion conductor additive, wherein the lithium ion conductor additive comprises a NASICON type lithium ceramic electrolyte, a perovskite type lithium ceramic electrolyte, a garnet type lithium ceramic electrolyte, a LISICON type lithium ceramic electrolyte, Li₃N-type lithium ceramic electrolyte, lithiated BPO₄Lithium-conducting ceramic electrolyte and lithium ion battery using the same₄SiO₄Any one or a combination of two or more of lithium ceramic electrolytes as a precursor.

38. The method of claim 33, wherein: the second solvent comprises any one or the combination of more than two of water, alcohol and ketone.

39. The method of claim 38, wherein: the alcohol comprises ethanol and/or isopropanol.

40. The method of claim 38, wherein: the ketone comprises acetone.

41. A method for producing a solid positive electrode, characterized by comprising: preparing a solid positive electrode composite material according to the method of any one of claims 1 to 40, and uniformly coating the solid positive electrode composite material on a positive electrode current collector to obtain a solid positive electrode.

42. Use of a solid state positive electrode composite material prepared by the method of any one of claims 1-40 or a solid state positive electrode prepared by the method of claim 41 in the manufacture of an electrochemical device.

43. Use according to claim 42, characterized in that: the electrochemical device includes an energy storage device and/or an electrochromic device.

44. Use according to claim 43, characterized in that: the energy storage device includes a battery.

45. Use according to claim 43, characterized in that: the electrochromic device includes an electronic book.

46. Use according to claim 45, characterized in that: the electronic book comprises a black-and-white electronic book and/or a color electronic book.