CN117712468A - Surface amorphous oxygen-containing solid electrolyte and preparation method and application thereof - Google Patents

Surface amorphous oxygen-containing solid electrolyte and preparation method and application thereof Download PDF

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Publication number
CN117712468A
CN117712468A CN202311670149.6A CN202311670149A CN117712468A CN 117712468 A CN117712468 A CN 117712468A CN 202311670149 A CN202311670149 A CN 202311670149A CN 117712468 A CN117712468 A CN 117712468A
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solid electrolyte
containing solid
oxygen
amorphous
crystalline
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邹魁
李延凤
周龙捷
李立飞
王振伟
赵辉
何培琪
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Jiangsu Langu New Energy Technology Co ltd
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Jiangsu Langu New Energy Technology Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0088—Composites
    • H01M2300/0094—Composites in the form of layered products, e.g. coatings
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Condensed Matter Physics & Semiconductors (AREA)
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Abstract

The invention provides a surface amorphous oxygen-containing solid electrolyte, a preparation method and application thereof. The surface amorphous oxygen-containing solid electrolyte comprises a crystalline oxygen-containing solid electrolyte body and an amorphous oxygen-containing solid electrolyte surface layer in-situ contacted with the body, so that the amorphous surface layer can be contacted with the crystalline atomic level, and the interface contact resistance is greatly reduced. Unlike the rigid oxygen-containing solid electrolyte in the prior art, the surface amorphous oxygen-containing solid electrolyte has better flexibility, can improve the wettability with the electrolyte when contacting with the electrolyte, is used for pole piece blending, and can greatly improve the liquid absorption rate of the pole piece; the coating method is used for coating the diaphragm, can improve the wettability of the diaphragm and electrolyte, and can reduce the internal resistance of the battery; the coating material is used for coating the anode material, and can improve the chemical stability and electrochemical stability of the anode material and electrolyte. In addition, the preparation method is simple, low in cost and convenient for realizing large-scale production.

Description

Surface amorphous oxygen-containing solid electrolyte and preparation method and application thereof
Technical Field
The invention belongs to the technical field of lithium battery preparation, and particularly relates to a surface amorphous oxygen-containing solid electrolyte, and a preparation method and application thereof.
Background
The lithium ion battery is widely applied to the fields of electronic products, electric automobiles, military industry, aerospace and the like because of the advantages of high energy density, long cycle life and the like. In particular, in recent years, the improvement of the requirements of the electric automobile on the endurance mileage has become a research hot spot how to improve the energy density of the lithium ion battery.
Solid-state batteries have a higher advantage in terms of safety and energy density as a next-generation battery technology than liquid lithium ion batteries. However, since many scientific problems of the solid-state battery are not solved, the development of the hybrid solid-liquid battery as a technical transition at present has become an industry consensus. In the mixed solid-liquid battery, the electrochemical performance of the battery can be effectively improved by coating the electrode with the oxygen-containing solid electrolyte, blending the electrode pole piece or coating the separator. However, since the oxygen-containing solid electrolyte is an inorganic rigid particle, there is a problem of poor wettability when in contact with the electrolyte, and the interface resistance increases, which affects the electrochemical performance of the lithium ion battery.
In the technical field of all-solid-state batteries, CN107611476B discloses a preparation method of an inorganic solid-state electrolyte with an amorphous substance on the surface, which comprises the following three steps: the first step, pressing the crystalline solid electrolyte under a high pressure and sintering the pressed solid electrolyte into a solid electrolyte ceramic sheet; the second step is to amorphize the crystalline solid electrolyte by melt quenching or high-energy ball milling to prepare amorphous solid electrolyte powder; and thirdly, mixing amorphous solid electrolyte powder with a binder and a solvent to prepare composite slurry, and coating the mixed slurry containing the amorphous solid electrolyte on the surface of the crystalline solid electrolyte ceramic sheet prepared in the first step through coating. Although the method can obtain the inorganic solid electrolyte with the amorphous surface, as the amorphous state is compounded on the surface of the crystalline electrolyte in a coating mode, the contact between the amorphous state and the crystalline state is still macroscopic solid-solid contact, and the interface contact resistance is large. In addition, the technical scheme is that the crystalline solid electrolyte is prepared into the ceramic sheet, so that after the amorphous coating layer is added, the wettability of metallic lithium is improved, and the contact between the solid electrolyte and a lithium negative electrode in the all-solid-state battery is improved. In the solid-liquid hybrid battery at the present stage, the metal lithium used for the negative electrode has the problems of unstable interface, penetration of lithium dendrite through the diaphragm, huge volume change and the like, so the ceramic plate prepared by the method is not suitable for the solid-liquid hybrid battery, and the ceramic plate cannot be used for positive electrode coating, pole piece blending or diaphragm coating and the like.
Disclosure of Invention
In view of the above, the present invention aims to provide a surface amorphous oxygen-containing solid electrolyte, and a preparation method and application thereof. The surface amorphous oxygen-containing solid electrolyte is in a powder form, can improve the wettability with electrolyte when contacting with the electrolyte, is used for pole piece blending, and can greatly improve the liquid absorption rate of the pole piece; the coating method is used for coating the diaphragm, so that the wettability of the diaphragm and electrolyte can be improved, and the internal resistance of the battery can be reduced; the coating material is used for coating the anode material, and can improve the chemical stability and the electrochemical stability of the anode material and the electrolyte.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a surface layer amorphous oxygen-containing solid electrolyte comprising a crystalline oxygen-containing solid electrolyte body and an amorphous oxygen-containing solid electrolyte surface layer in-situ contact with the crystalline oxygen-containing solid electrolyte body.
Preferably, the particle size of the crystalline oxygen-containing solid electrolyte body is 100-500 nm.
Preferably, the thickness of the amorphous oxygen-containing solid electrolyte surface layer is 5-50 nm.
Preferably, the crystalline oxygen-containing solid electrolyte body is selected from the following materials:
Li 4 XO 4 si, ge, ti, zr or Li 3 YO 4 Wherein X is at least one of Si, ge, ti or Zr, and Y is at least one of P, as, V, nb or Ta;
or (b)
Li 1+x+3y A x B 2-x (P 1-y Si y O 4 ) 3 、Li 1+x+3y C x B 2-1.5x (P 1-y Si y O 4 ) 3 Or Li (lithium) 1+x+3y D x B 2-1.75x (P 1- y Si y O 4 ) 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein a is at least one of Al, fe, sc, lu, Y, la, cr, ga or In; b is at least one of Ti, ge, zr, hf or Sn; c is at least one of V, nb or Ta; d is at least one of Mo or W; x is more than 0 and less than 0.6,0, y is more than or equal to 0.6;
or (b)
Li 1+x H 1-x Al(PO 4 )O 1-y M 2y Wherein 0.ltoreq.x<1，0<y<0.1, M is F, cl, br or I
At least one of (a) and (b);
or (b)
Li x A’ 3 B’ 2 O 12 The method comprises the steps of carrying out a first treatment on the surface of the Wherein A' is at least one of La, nb, mg, ba, ca or Sr; b' is at least one of Te, ta, nb, zr or In; x is more than 0 and less than or equal to 7;
or (b)
Li 3x La 2/3-x TiO 3 ；0＜x≤2/3；
Or (b)
Li 3 OX’、Li 3-2x A” x B”O、Li 1.9 OHCl 0.9 Or Li (lithium) 2 At least one of OHCl; wherein X' is at least one of F, cl, br or I; a' is at least one of Mg, ca, sr or Ba; b' is Cl and/or I; x is more than or equal to 0 and less than 3/2;
or (b)
Li-Al-Si-O system compounds specifically include: li (Li) 3 AlSiO 5 、LiAlSi 2 O 6 、LiAlSi 4 O 10 、LiAlSi 2 O 6 Or LiAlSiO 4 At least one of them.
In a second aspect, the present invention provides a method for preparing the surface amorphous oxygen-containing solid electrolyte, comprising the steps of:
s1: mixing crystalline oxygen-containing solid electrolyte body particles with a solvent, and performing first sanding treatment to obtain submicron crystalline oxygen-containing solid electrolyte body slurry;
S2: pretreating the submicron crystalline oxygen-containing solid electrolyte bulk slurry under the action of a pretreatment agent;
s3: mixing the pretreated crystalline oxygen-containing solid electrolyte body slurry with an amorphous additive, and performing second sanding treatment to obtain a surface amorphous oxygen-containing solid electrolyte;
preferably, the pretreatment agent is any one or more of oxalic acid, citric acid, pyruvic acid, acetic acid, salicylic acid or phenylglycolic acid.
Preferably, the pretreatment agent is added in an amount of 0.1 to 10wt% based on the mass of the crystalline oxygen-containing solid electrolyte bulk particles.
Preferably, the preprocessing in step S2 is specifically: adding the pretreatment agent to the submicron crystalline oxygen-containing solid electrolyte bulk slurry, in the presence of100～300Stirring and homogenizing for 1-5 h at rpm.
Preferably, the amorphous additive in step S3 is selected from any one or more of amorphous alumina, amorphous silica, amorphous titania and amorphous zirconia.
Preferably, the average particle diameter of the amorphous additive is 10 to 50nm.
Preferably, the amorphous additive is present in the form of an amorphous additive suspension.
Preferably, the amorphous additive suspension is obtained by mixing an amorphous additive with a suspension medium and dispersing the mixture.
Preferably, the suspension medium is the same material as the solvent in the submicron crystalline oxygen-containing solid electrolyte slurry
Preferably, the addition amount of the amorphous additive suspension is 10-30wt% of the mass of the submicron crystalline oxygen-containing solid electrolyte body slurry.
Preferably, in the amorphous additive suspension, the mass ratio of the amorphous additive to the suspension medium is 1:10-3.5:10.
Preferably, the mass ratio of the solvent to the crystalline oxygen-containing solid electrolyte bulk particles is 2:1 to 5:1.
Preferably, the solvent is selected from any one or more of deionized water, absolute ethanol, isopropanol or N-methylpyrrolidone.
Preferably, the first sanding treatment is performed in the presence of a first abrasive ball.
Preferably, the mass ratio of the crystalline oxygen-containing solid electrolyte bulk particles to the first grinding balls is 1 (5-20).
Preferably, the second sanding treatment is performed in the presence of a second abrasive ball.
Preferably, the mass ratio of the crystalline oxygen-containing solid electrolyte bulk particles to the second grinding balls is 1 (5-20);
the first grinding balls and the second grinding balls are respectively and independently selected from zirconia balls, alumina balls or agate balls, and the diameters of the first grinding balls and the second grinding balls are respectively and independently selected from 0.1-0.6 mm;
The linear speeds of the first sanding treatment and the second sanding treatment are respectively and independently selected from 15-25 m/s.
Preferably, the time of the first sanding treatment in step S1 is 8 to 24 hours.
Preferably, the second sanding treatment in step S3 takes 1 to 5 hours.
In a third aspect, the invention provides an application of the surface amorphous oxygen-containing solid electrolyte in positive electrode coating, diaphragm coating or pole piece blending.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention provides a surface amorphous oxygen-containing solid electrolyte, which can greatly reduce interface contact resistance by generating an amorphous surface layer on the surface of a crystalline oxygen-containing solid electrolyte body in situ to realize atomic-level contact of the amorphous surface layer and the crystalline oxygen-containing solid electrolyte body. Unlike available technology, the present invention provides amorphous oxygen-containing solid electrolyte with excellent flexibility, and the amorphous oxygen-containing solid electrolyte has raised electrolyte wetting performance, high pole piece liquid absorption rate; the coating method is used for coating the diaphragm, so that the wettability of the diaphragm and electrolyte can be improved, and the internal resistance of the battery can be reduced; the coating material is used for coating the anode material, so that the chemical stability and the electrochemical stability of the anode material and the electrolyte can be improved;
(2) The invention provides a preparation method of a surface amorphous oxygen-containing solid electrolyte, which comprises the steps of firstly carrying out submicron treatment on the oxygen-containing solid electrolyte in a sand mill, and then adding a pretreatment agent into submicron oxygen-containing solid electrolyte slurry. The pretreatment agent has certain acidity, can effectively destroy the crystal structure of the solid electrolyte, introduces line defects, surface defects and bulk defects, and accelerates the surface amorphization of powder. The pretreatment agent has a certain acidity but is less corrosive and acidic than inorganic acids such as hydrofluoric acid, sulfuric acid, and hydrochloric acid. Inorganic acids such as hydrofluoric acid, sulfuric acid, hydrochloric acid, etc. have strong acidity, and when in contact with the solid electrolyte, they react with the solid electrolyte, and cause decomposition of the solid electrolyte.
In the present invention, the higher the content of the pretreatment agent, the higher the degree of amorphization of the oxygen-containing solid electrolyte. The thickness of the amorphous layer of the oxygen-containing solid electrolyte is controlled by controlling the content of the pretreatment agent.
And then uniformly mixing amorphous additive powder (such as amorphous aluminum oxide, amorphous silicon oxide, amorphous titanium oxide and amorphous zirconium oxide) with the pretreated crystalline oxygen-containing solid electrolyte body slurry, and then sanding. In the process, the amorphous additive powder is in an amorphous form, and the amorphous additive is very easy to cause amorphization of the surface of the solid electrolyte through extrusion collision under the drive of a grinding medium of a sand mill in the grinding process. In addition, the invention can also effectively control the thickness of the amorphous layer on the surface of the solid electrolyte by adjusting the addition amount of the amorphous additive and the corresponding parameters of the grinding process, thereby achieving the ideal amorphization effect of the surface of the oxygen-containing solid electrolyte. The preparation method has simple process and low cost, and is convenient for realizing large-scale industrial production.
Drawings
FIG. 1 is a schematic diagram of the structure of a surface layer amorphized oxygen-containing solid electrolyte provided by the invention;
FIG. 2 is a TEM image of the surface-layer-amorphized oxygen-containing solid electrolyte obtained in example 1;
FIG. 3 is a TEM image of the crystalline oxygen-containing solid electrolyte obtained in comparative example 1;
fig. 4 is a TEM image of the fully amorphous oxygen-containing solid electrolyte obtained in comparative example 2.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Aiming at the problem that amorphous and crystalline contacts in the surface amorphous inorganic solid electrolyte are still macroscopic solid-solid contacts in the prior art and have larger interface contact resistance, the invention provides a surface amorphous oxygen-containing solid electrolyte, the structure of which is shown in figure 1, which comprises a crystalline oxygen-containing solid electrolyte body and an amorphous oxygen-containing solid electrolyte surface layer in-situ contact with the crystalline oxygen-containing solid electrolyte body.
In the present invention, the particle diameter of the crystalline oxygen-containing solid electrolyte bulk is preferably 100 to 500nm, more preferably 200 to 300nm, and the oxygen-containing solid electrolyte bulk material is selected from the group consisting of an oxide solid electrolyte and an oxygen-doped halide solid electrolyte, more specifically, including but not limited to any one of the following materials (1) to (7):
(1)、Li 4 XO 4 Si，Ge，ti, zr or Li 3 YO 4 Wherein X is at least one of Si, ge, ti or Zr, and Y is at least one of P, as, V, nb or Ta;
(2)、Li 1+x+3y A x B 2-x (P 1-y Si y O 4 ) 3 、Li 1+x+3y C x B 2-1.5x (P 1-y Si y O 4 ) 3 or Li (lithium) 1+x+3y D x B 2-1.75x (P 1- y Si y O 4 ) 3 ；
Wherein a is at least one of Al, fe, sc, lu, Y, la, cr, ga or In; b is at least one of Ti, ge, zr, hf or Sn; c is at least one of V, nb or Ta; d is at least one of Mo or W; x is more than 0 and less than 0.6,0, y is more than or equal to 0.6;
(3)、Li 1+x H 1-x Al(PO 4 )O 1-y M 2y wherein 0.ltoreq.x<1，0<y<0.1, M is at least one of F, cl, br or I;
(4)、Li x A’ 3 B’ 2 O 12 the method comprises the steps of carrying out a first treatment on the surface of the Wherein A' is at least one of La, nb, mg, ba, ca or Sr; b' is at least one of Te, ta, nb, zr or In; x is more than 0 and less than or equal to 7;
(5)、Li 3x La 2/3-x TiO 3 ；0＜x≤2/3；
(6)、Li 3 OX’、Li 3-2x A” x B”O、Li 1.9 OHCl 0.9 or Li (lithium) 2 At least one of OHCl; wherein X' is at least one of F, cl, br or I; a' is at least one of Mg, ca, sr or Ba; b' is Cl and/or I; x is more than or equal to 0 and less than 3/2;
(7) Li-Al-Si-O system compounds, specifically including: li (Li) 3 AlSiO 5 、LiAlSi 2 O 6 、LiAlSi 4 O 10 、LiAlSi 2 O 6 Or LiAlSiO 4 At least one of them.
In the invention, the submicron oxygen-containing solid electrolyte is obtained by first performing first sanding treatment on a crystalline oxygen-containing solid electrolyte body, and then adding a pretreatment agent into the submicron oxygen-containing solid electrolyte slurry. The pretreatment agent is any one or more of oxalic acid, citric acid, pyruvic acid, acetic acid, salicylic acid or phenylglycolic acid. Wherein the addition amount of the pretreatment agent is preferably 0.1 to 10wt%, more preferably 2 to 5wt% of the mass of the solid electrolyte powder. The pretreatment agent has certain acidity, can effectively destroy the crystal structure of the solid electrolyte, introduces line defects, surface defects and bulk defects, and accelerates the surface amorphization of powder. And then, continuing to carry out second sanding treatment by adding an amorphous additive, wherein in extrusion collision of the second sanding treatment, the amorphous additive causes amorphization of the surface of the crystalline oxygen-containing solid electrolyte, so that the amorphous oxygen-containing solid electrolyte surface layer in-situ contact with the crystalline oxygen-containing solid electrolyte body is obtained.
In the invention, the pretreatment agent is any one or more of oxalic acid, citric acid, pyruvic acid, acetic acid, salicylic acid and phenylglycolic acid.
The addition amount of the pretreatment agent is 0.1 to 10 weight percent of the mass of the solid electrolyte powder
In the present invention, the thickness of the surface layer of the amorphous oxygen-containing solid electrolyte is preferably 5 to 50nm, and may be 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, or the like.
The invention provides the amorphous oxygen-containing solid electrolyte on the surface layer, and the amorphous surface layer is in-situ generated on the surface of the crystalline oxygen-containing solid electrolyte body, so that the amorphous surface layer is in atomic level contact with the crystalline oxygen-containing solid electrolyte body, and the interface contact resistance can be greatly reduced. Unlike available technology, the present invention provides amorphous oxygen-containing solid electrolyte with excellent flexibility, and the amorphous oxygen-containing solid electrolyte has raised electrolyte wetting performance, high pole piece liquid absorption rate; the coating method is used for coating the diaphragm, so that the wettability of the diaphragm and electrolyte can be improved, and the internal resistance of the battery can be reduced; the coating material is used for coating the anode material, and can improve the chemical stability and the electrochemical stability of the anode material and the electrolyte.
The invention also provides a preparation method of the surface amorphous oxygen-containing solid electrolyte, which comprises the following steps:
S1: mixing crystalline oxygen-containing solid electrolyte body particles with a solvent, and performing first sanding treatment to obtain submicron crystalline oxygen-containing solid electrolyte body slurry;
s2: pretreating the submicron crystalline oxygen-containing solid electrolyte body slurry under the action of a pretreatment agent;
s3: and mixing the pretreated crystalline oxygen-containing solid electrolyte body slurry with an amorphous additive, and performing second sanding treatment to obtain the surface amorphous oxygen-containing solid electrolyte.
According to the invention, crystalline oxygen-containing solid electrolyte bulk particles are first mixed with a solvent and then subjected to a first sanding treatment to obtain submicron crystalline oxygen-containing solid electrolyte bulk slurry. Wherein the crystalline oxygen-containing solid electrolyte bulk particles can be purchased directly or prepared according to methods of preparation well known to those skilled in the art. After the crystalline oxygen-containing solid electrolyte bulk particles are obtained, they are mixed with a solvent and subjected to a first sanding treatment. The invention preferably uses jaw crusher, mechanical crushing and jet milling to crush crystalline oxygen-containing solid electrolyte body particles into powder, and then mixes the powder with solvent to carry out first sand milling treatment. In the invention, the solvent is selected from any one or more of deionized water, absolute ethyl alcohol, isopropanol or N-methyl pyrrolidone. The mass ratio of the solvent to the crystalline oxygen-containing solid electrolyte bulk particles is preferably 2:1-5:1, and can be specifically 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1 or the like. In the present invention, the abrasive balls used in the first sanding treatment may be zirconia balls, alumina balls or agate balls, preferably zirconia balls; the diameter of the grinding balls is 0.1-0.6 mm, preferably 0.3mm. The ball-to-material ratio in the first sanding treatment is (5-20): 1, and can be 5:1, 8:1, 10:1, 12:1, 15:1, 18:1, 20:1 or the like. In the invention, the ball-to-material ratio is the mass of grinding balls, namely the mass of crystalline oxygen-containing solid electrolyte body particles. The first sanding treatment is preferably carried out in a sand mill, where The linear speed of the sand mill is 15-25 m/s, and can be specifically 15m/s, 16m/s, 17m/s, 18m/s, 19m/s, 20m/s, 21m/s, 22m/s, 23m/s, 24m/s or 25m/s, etc. In the present invention, after the crystalline oxygen-containing solid electrolyte bulk particles and the solvent are mixed in proportion according to the parameters of the first sand milling treatment, the first sand milling is carried out for 8 to 24 hours, preferably 12 to 20 hours, and the medium particle diameter (D 50 ) Stopping the first sand grinding when the wavelength is within the range of 100-500 nm, and obtaining the submicron crystalline oxygen-containing solid electrolyte body slurry.
According to the invention, after obtaining submicron crystalline oxygen-containing solid electrolyte bulk slurry, pretreatment is carried out under the action of a pretreatment agent. And mixing the amorphous additive with the amorphous additive, and then continuing to carry out second sanding treatment to obtain the surface amorphous oxygen-containing solid electrolyte. The selection and the dosage of the pretreatment agent are consistent with those of the technical scheme, and are not repeated here. In some preferred embodiments of the present invention, the amorphous additive is present in the form of an amorphous additive suspension, preferably mixed with a suspension medium, which preferably is consistent with the solvent in the submicron crystalline oxygen-containing solid electrolyte bulk slurry, so as to avoid some unknown possible side reactions of the various solvents present in the prepared slurry, affecting the control of amorphization and the performance of the solid electrolyte. In the invention, in the amorphous additive suspension, the mass ratio of the amorphous additive to the suspension medium is 1:10-3.5:10, and specifically can be 1:10, 1.5:10, 2:10, 2.5:10, 3:10, 3.5:10 or the like. Then, the mixed suspension of the amorphous additive and the suspension medium is preferably subjected to ultrasonic dispersion by adopting a 600W ultrasonic dispersing machine so as to ensure that the amorphous additive powder is uniformly dispersed in the suspension medium to form uniform amorphous additive suspension, and then the amorphous additive suspension is mixed with submicron crystalline oxygen-containing solid electrolyte body slurry and subjected to second sanding treatment. In the present invention, the amorphous additive includes, but is not limited to, any one or more of amorphous aluminum oxide, amorphous silicon oxide, amorphous titanium oxide, or amorphous zirconium oxide. It is considered that the larger the addition amount of the amorphous additive suspension, the larger the amorphous layer thickness of the solid electrolyte surface. The dosage and the grain size of the amorphous additive are important indexes for controlling the amorphization degree, too little dosage cannot play the amorphization role, too much dosage has too strong action effect, can cause the amorphous layer to be too thick or completely amorphized, and can influence the transmission performance of lithium ions in the solid electrolyte. Thus, in the present invention, the particle diameter of the crystalline oxygen-containing solid electrolyte body is 100 to 500nm, wherein the average particle diameter of the amorphous additive is preferably 10 to 50nm, and specifically may be 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, or the like; the addition amount of the amorphous additive suspension is preferably 10 to 30wt% of the mass of the submicron crystalline oxygen-containing solid electrolyte bulk slurry, and specifically may be 10wt%, 12wt%, 15wt%, 17wt%, 20wt%, 22wt%, 25wt%, 27wt%, 30wt%, or the like. In the present invention, the ball-to-material ratio, the grinding ball, the diameter thereof, and the linear velocity of the second sanding process are the same as those of the first sanding process, and will not be described herein. In the present invention, the time of the second sanding treatment in this step is preferably 1 to 5 hours, and may be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or the like. In the invention, the product obtained after the second sanding treatment is surface amorphous oxygen-containing solid electrolyte slurry, so the invention preferably dries the slurry at 100-120 ℃, preferably 110 ℃ to obtain powder agglomerated into a block, and the powder is ground by a mortar and passes through a 80-400-mesh screen to obtain the surface amorphous oxygen-containing solid electrolyte.
In the present invention, the above-listed point values are merely illustrative and not limited, and other point values within the numerical range are applicable, and are not repeated here to avoid complexity.
According to the preparation method of the surface amorphous oxygen-containing solid electrolyte, firstly, under the high-speed rotation of a rotor of a sand mill through the first sand milling treatment, large-particle oxygen-containing solid electrolytes (hereinafter referred to as materials) collide, grinding balls cut the large-particle materials, and break the large-particle materials, so that crystalline submicron-sized particles with smaller particle sizes are obtained, and in the subsequent grinding process, the particle sizes of the oxygen-containing solid electrolytes are smaller and smaller, but still remain crystalline. The pretreatment agent and the amorphous additive are added into the system, and the pretreatment agent is any one or more of oxalic acid, citric acid, pyruvic acid, acetic acid, salicylic acid and phenylglycolic acid. The pretreatment agent has certain acidity and can effectively destroy the crystal structure of the solid electrolyte. And then adding an amorphous additive, wherein the amorphous additive is in an amorphous form and has a particle size of 10-50 nm, and the amorphous additive is extremely easy to cause amorphization of the surface of the solid electrolyte through extrusion collision under the drive of a grinding medium of a sand mill in the second grinding process. In addition, the thickness of the amorphous layer on the surface of the solid electrolyte can be effectively controlled by adjusting the addition amount of the amorphous additive suspension and the grinding process, so that the ideal amorphous effect on the surface of the solid electrolyte can be achieved. It is generally considered that the larger the linear speed of the sand mill is, the longer the grinding time is, and the larger the thickness of the amorphous layer is, and conversely, the smaller the thickness of the amorphous layer is, after a certain amount of the amorphous additive suspension is added. In addition, the preparation method has simple process and low cost, and is convenient for realizing large-scale industrial production.
In the present invention, TEM test was performed on the obtained surface layer amorphous oxygen-containing solid electrolyte material powder, and the thickness of the amorphous layer thereof was tested. Tests show that compared with the TEM image (such as 3) of the crystalline oxygen-containing solid electrolyte and the TEM image (figure 4) of the completely amorphous oxygen-containing solid electrolyte, the TEM image of the surface amorphous oxygen-containing solid electrolyte material powder provided by the invention is shown as figure 2, the TEM image of the surface amorphous oxygen-containing solid electrolyte material powder can be seen to have orderly and ordered internal atomic arrangement, maintain a crystalline structure, extend outwards at the edge of the crystalline state, gradually disorder the atomic arrangement, namely an amorphous layer, the demarcation is not particularly obvious, and the crystalline layer and the amorphous layer belong to atomic level contact.
The invention also provides application of the prepared surface layer amorphized oxygen-containing solid electrolyte, which comprises positive electrode coating, diaphragm coating and pole piece blending.
In some embodiments of the invention, the surface layer amorphized oxygen-containing solid electrolyte is used with a coating machine for the positive ternary material NCM811 (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) And (5) coating. After the coating is finished, the anode ternary material coated with the surface amorphous oxygen-containing solid electrolyte can be obtained after sintering for 4 to 10 hours at the temperature of 400 to 800 ℃. The coating amount of the surface amorphous oxygen-containing solid electrolyte is 0.5-2 wt% of the positive electrode material. It should be noted that the present invention is not limited to the ternary material of NCM811, and other ternary materials of positive electrode known to those skilled in the art are also applicable, such as NCM523 (LiNi 0.5 Co 0.2 Mn 0.3 O 2 )、NCM622(LiNi 0.6 Co 0.2 Mn 0.2 O 2 ) Etc.
After the positive electrode is coated, the coated positive electrode is preferably assembled into a 2032 button cell, the electrochemical performance test is carried out, the test of the cell is carried out under the constant temperature condition of 25 ℃, and the charge and discharge modes are as follows: constant current is firstly carried out, then constant voltage is carried out for 30 minutes for charging and constant current discharging. For the test of cycle performance, the battery was first activated three times by 0.1C low current charge-discharge, and then charged and discharged 100 times by 0.5C constant current. For the rate performance test, the battery is respectively charged and discharged in a constant current manner at 1C in a voltage interval of 2.75-4.3V.
In some embodiments of the invention, the surface layer amorphous oxygen-containing solid electrolyte powder is taken to prepare oil-based slurry according to the solid content of 30%, a certain proportion of wetting agent and binder are added to prepare composite slurry, the composite slurry is coated on a polyethylene diaphragm or a polypropylene diaphragm on one side or both sides by using a diaphragm coating machine, and the diaphragm coated by the surface layer amorphous oxygen-containing solid electrolyte is obtained after drying. Wherein the wetting agent and the binder are selected according to routine practice by a person skilled in the art. For example, isopropanol, alkyl sulfonate, sulfonate anionic surfactant, silanol nonionic surfactant or siloxane surfactant, etc. may be used as wetting agent, and carboxymethyl cellulose (CMC), water-based polyacrylate, polyvinyl alcohol or organosilicon modified acrylic resin, etc. may be used as adhesive. After the separator coating is completed, the invention preferably assembles 2032 button cell from the coated separator for electrochemical performance testing. The testing method of the battery is consistent with the testing method of the battery with the coated positive electrode.
In some embodiments of the invention, anode materials NCM811, polyvinylidene fluoride (PVDF), conductive carbon black (SP) and the surface amorphous oxygen-containing solid electrolyte are subjected to anode homogenization according to the mass ratio of 90:4:4:2, coated on an aluminum foil current collector, dried by an oven, and rolled on a roll squeezer to prepare a required anode sheet; wherein polyvinylidene fluoride (PVDF) is used as a binder, conductive carbon black (SP) is used as a conductive agent, a positive electrode material NCM811 is used as a positive electrode active substance, and the surface layer amorphized oxygen-containing solid electrolyte is used as a blending additive. The electrochemical performance of the blended pole piece assembled 2032 button cell is tested.
In order to further illustrate the present invention, the following examples are provided.
Example 1
1. Solid electrolyte powder Li containing oxygen 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Adding 400g and 1600g of deionized water into a sand mill, performing first sand milling by using a zirconia grinding ball with the thickness of 0.6mm for 24 hours, wherein the ball-material ratio is 20, the linear speed of the first sand mill is 25m/s, stopping the first sand milling when the average particle size is 300nm, obtaining submicron solid electrolyte slurry, and discharging for later use;
2. citric acid is added into the submicron solid electrolyte slurry as a pretreatment agent, wherein the amount of the citric acid is 0.1wt% of the amount of the oxygen-containing solid electrolyte powder, and the slurry is homogenized for 1h.
3. Weighing 50nm amorphous zirconia powder and deionized water according to a mass percentage of 1:10, and using a 600W ultrasonic dispersing machine to uniformly ultrasonically disperse the amorphous zirconia powder in the deionized water to form uniformly dispersed amorphous zirconia suspension;
4. 600g of the above amorphous zirconia suspension was added to the pretreated solid-state electrolyte slurry obtained in step 2. Continuously performing second sand grinding for 1h under the same condition to obtain oxygen-containing solid electrolyte slurry with an amorphized surface layer;
5. the slurry was dried at 120 ℃. And (3) drying to obtain powder agglomerated into blocks, grinding the powder by using a mortar, and sieving the powder with a 400-mesh sieve to obtain the oxygen-containing solid electrolyte material powder with the amorphous surface layer.
Example 2
The same materials as in example 1 were used, except that citric acid was added in an amount of 0.5wt% based on the amount of the solid electrolyte powder, and homogenized for 1 hour. The mass ratio of the amorphous additive zirconia to the solvent is 1.5:10, the second sanding time is 1.5 hours, and other preparation conditions are the same.
Example 3
The same materials as in example 1 were used, except that citric acid was added in an amount of 1.5wt% based on the amount of the solid electrolyte powder, and homogenized for 1 hour. The mass ratio of the amorphous additive zirconia to the solvent is 2:10, the second sanding time is 1.5 hours, and other preparation conditions are the same.
Example 4
The same materials as in example 1 were used, except that citric acid was added in an amount of 3.5wt% based on the amount of the solid electrolyte powder, and homogenized for 1 hour. The mass ratio of the amorphous additive zirconia to the solvent is 2.6:10, the second sanding time is 2 hours, and other preparation conditions are the same.
Example 5
The same materials as in example 1 were used, except that citric acid was added in an amount of 6wt% based on the amount of the solid electrolyte powder, and homogenized for 2 hours. The mass ratio of the amorphous additive zirconia to the solvent is 3:10, the second sanding time is 2.5 hours, and other preparation conditions are the same.
Example 6
The same materials as in example 1 were used except that citric acid was added in an amount of 8.5wt% based on the amount of the solid electrolyte powder, and homogenized for 3 hours. The mass ratio of the amorphous additive zirconia to the solvent is 3.5:10, the second sanding time is 4.5 hours, and other preparation conditions are the same.
Example 7
1. Solid electrolyte powder Li containing oxygen 7 La 3 Zr 2 O 12 Adding 500g and 1500g of absolute ethyl alcohol into a sand mill, selecting 0.1mm zirconia grinding balls for first sand milling for 8 hours, wherein the ball-to-material ratio is 5, the linear speed of the sand mill is 15m/s, monitoring the particle size, and stopping the first sand milling when the average particle size is 100nm to obtain submicron solid-state electricityDischarging the electrolyte slurry for standby;
2. Adding pyruvic acid as a pretreatment agent into the submicron solid electrolyte slurry, wherein the pyruvic acid accounts for 2wt% of the oxygen-containing solid electrolyte powder, and homogenizing for 2 hours;
3. weighing 10nm amorphous titanium oxide powder and absolute ethyl alcohol according to a mass percentage of 1:10, and then using a 600W ultrasonic dispersing machine to uniformly ultrasonically disperse the amorphous titanium oxide powder in the absolute ethyl alcohol to form uniformly dispersed amorphous titanium oxide suspension;
4. 200g of the amorphous titanium oxide suspension was added to the pretreated solid electrolyte slurry obtained in step 2. Under the same condition, continuing to sand for 5 hours to obtain oxygen-containing solid electrolyte slurry with the amorphized surface layer;
5. the slurry was dried at 100 ℃. And (3) drying to obtain powder agglomerated into blocks, grinding the powder by using a mortar, and then sieving the powder with a 80-mesh sieve to obtain the oxygen-containing solid electrolyte material powder with the amorphous surface layer.
Example 8
1. Solid electrolyte powder Li containing oxygen 3 Zr 2 Si 2 PO 12 Adding 500g and 1000g of isopropanol into a sand mill, performing first sand milling by using an alumina grinding ball with the thickness of 0.3mm for 12 hours, wherein the ball-material ratio is 10, the linear speed of the sand mill is 20m/s, monitoring the particle size, stopping the first sand milling when the average particle size is 200nm, obtaining submicron solid electrolyte slurry, and discharging for later use;
2. Adding acetic acid into the submicron solid electrolyte slurry as a pretreatment agent, wherein the amount of the acetic acid is 2 weight percent of the amount of the oxygen-containing solid electrolyte powder, and homogenizing for 2 hours;
3. weighing 30nm amorphous silicon oxide powder and isopropanol according to a mass percentage of 2:10, and using a 600W ultrasonic dispersing machine to uniformly ultrasonically disperse the amorphous silicon oxide powder in the isopropanol to form uniformly dispersed amorphous silicon oxide suspension;
4. 300g of the above amorphous silicon oxide suspension was added to the submicron solid electrolyte slurry obtained in step 2. Continuing the second sand grinding for 3 hours to obtain oxygen-containing solid electrolyte slurry with the amorphized surface layer;
5. the slurry was dried using a temperature of 110 ℃. And (3) drying to obtain powder agglomerated into blocks, grinding the powder by using a mortar, and sieving the powder with a 200-mesh sieve to obtain the oxygen-containing solid electrolyte material powder with the amorphous surface layer.
Example 9
1. Solid electrolyte powder Li containing oxygen 0.33 La 0.56 TiO 3 Adding 300g and 1500g of N methyl pyrrolidone into a sand mill, selecting 0.3mm zirconia ball grinding balls for first sand milling for 10 hours, wherein the ball-to-material ratio is 5, the linear speed of the sand mill is 15m/s, monitoring the particle size, stopping the first sand milling when the average particle size is 100nm, obtaining submicron solid electrolyte slurry, and discharging for later use;
2. Adding salicylic acid into the submicron solid electrolyte slurry as a pretreatment agent, wherein the salicylic acid accounts for 3 weight percent of the oxygen-containing solid electrolyte powder, and homogenizing for 4 hours;
3. weighing 30nm amorphous alumina powder and N-methyl pyrrolidone according to a mass percentage of 3:10, and using a 600W ultrasonic dispersing machine to uniformly ultrasonically disperse the amorphous alumina powder in the N-methyl pyrrolidone to form uniformly dispersed amorphous alumina suspension;
4. 180g of the above amorphous alumina suspension was added to the submicron solid electrolyte slurry obtained in step 2. Continuing the second sand grinding for 5 hours to obtain oxygen-containing solid electrolyte slurry with the amorphized surface layer;
5. the slurry was dried at 100 ℃. And (3) drying to obtain powder agglomerated into blocks, grinding the powder by using a mortar, and sieving the powder with a 300-mesh sieve to obtain the oxygen-containing solid electrolyte material powder with the amorphous surface layer.
Example 10
1. Oxygen-containing solid electrolyte powder LiAlSi 2 O 6 Adding 500g and 1500g of absolute ethyl alcohol into a sand mill, performing first sand milling by using 0.1mm alumina ball grinding balls for 8 hours, wherein the ball-to-material ratio is 20, the linear speed of the sand mill is 20m/s, monitoring the particle size, stopping the first sand milling when the average particle size is 200nm, obtaining submicron solid electrolyte slurry, and discharging for later use;
2. Adding phenylglycolic acid as a pretreatment agent into the submicron solid electrolyte slurry, wherein the amount of the phenylglycolic acid is 6 weight percent of the amount of the oxygen-containing solid electrolyte powder, and homogenizing for 4 hours;
3. weighing 50nm amorphous alumina powder and absolute ethyl alcohol according to a mass percentage of 2:10, and using a 600W ultrasonic dispersing machine to uniformly ultrasonically disperse the amorphous alumina powder in the absolute ethyl alcohol to form uniformly dispersed amorphous alumina suspension;
4. 600g of the above amorphous alumina suspension was added to the submicron solid electrolyte slurry obtained in step 2. Continuing the second sand grinding for 1h to obtain oxygen-containing solid electrolyte slurry with the amorphized surface layer;
5. the slurry was dried at 120 ℃. And (3) drying to obtain powder agglomerated into blocks, grinding the powder by using a mortar, and sieving the powder with a 400-mesh sieve to obtain the oxygen-containing solid electrolyte material powder with the amorphous surface layer.
Example 11
1. Solid electrolyte powder Li containing oxygen 4 GeO 4 Adding 300g and 1500g of deionized water into a sand mill, performing first sand milling by using an agate grinding ball with the thickness of 0.3mm for 16 hours, wherein the ball-to-material ratio is 15, the linear speed of the sand mill is 18m/s, monitoring the particle size, stopping the first sand milling when the average particle size is 200nm, obtaining a micron solid electrolyte slurry, and discharging for later use;
2. Adding phenylglycolic acid as a pretreatment agent into the submicron solid electrolyte slurry, wherein the phenylglycolic acid accounts for 9.5 weight percent of the oxygen-containing solid electrolyte powder, and homogenizing for 4 hours;
3. weighing amorphous titanium oxide powder with the mass percentage of 30nm and deionized water according to the mass percentage of 1:10, and using a 600W ultrasonic dispersing machine to uniformly ultrasonically disperse the amorphous titanium oxide powder in the deionized water to form uniformly dispersed amorphous titanium oxide suspension;
4. 360g of the amorphous titanium oxide suspension was added to the submicron solid electrolyte slurry obtained in step 3. Continuing the second sand grinding for 3 hours to obtain oxygen-containing solid electrolyte slurry with the amorphized surface layer;
5. the slurry was dried using a temperature of 110 ℃. And (3) drying to obtain powder agglomerated into blocks, grinding the powder by using a mortar, and then sieving the powder with a 80-mesh sieve to obtain the oxygen-containing solid electrolyte material powder with the amorphous surface layer.
Comparative example 1
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Except that no amorphization treatment was performed.
Comparative example 2
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Except that oxalic acid of 50wt% of the mass of the solid electrolyte powder was added, and amorphous zirconia was added as an amorphous additive to prepare completely amorphous Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 A material.
Comparative example 3
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Except that oxalic acid of 0.1wt% of the mass of the solid electrolyte powder was added, and amorphous zirconia was not added as an amorphous additive, to obtain an oxygen-containing solid electrolyte free of amorphization.
Comparative example 4
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 The difference is that citric acid with the mass of 1wt% of the solid electrolyte powder is added, and amorphous zirconia is not added as an amorphous additive, so that the oxygen-containing solid electrolyte without amorphization is obtained.
Comparative example 5
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Except that citric acid was not added as a pretreatment agent, and the rest of the operation procedure was the same as in example 1, to obtain an oxygen-containing solid electrolyte free from amorphization. Comparative example 6
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Except that oxalic acid was added in an amount of 0.05wt% based on the mass of the solid electrolyte powder. Amorphous zirconia was added as an amorphous additive in the same proportions as in the examples to prepare Li having an amorphous layer thickness of 3nm 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 A material.
Comparative example 7
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Oxalic acid with a mass of 20wt% of the solid electrolyte powder was added. Amorphous zirconia was added as an amorphous additive in the same proportions as in the examples to prepare Li having an amorphous layer thickness of 60nm 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 A material.
Comparative example 8
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Oxalic acid with 25wt% of the solid electrolyte powder mass is added. Amorphous zirconia was added as an amorphous additive in the same proportions as in the examples to prepare Li having an amorphous layer thickness of 68nm 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 A material.
Comparative example 9
The same oxygen-containing solid electrolyte Li as in example 1 was used 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 Oxalic acid with a mass of 30wt% of the solid electrolyte powder was added. Adding amorphous zirconia as an amorphous additive, wherein the ratio of 50nm amorphous zirconia to deionized water is 1.5:10, and preparing Li with the amorphous layer thickness of 82nm 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 A material. Comparative example 10
As in example 7, li is selected 7 La 3 Zr 2 O 12 The material is distinguished in that it has not been subjected to an amorphization treatment.
Comparative example 11
As in example 8, li is selected 3 Zr 2 Si 2 PO 12 The material is distinguished in that it has not been subjected to an amorphization treatment.
Comparative example 12
As in example 9, li is selected 0.33 La 0.56 TiO 3 The material is distinguished in that it has not been subjected to an amorphization treatment.
Comparative example 13
As in example 10, liAlSi is selected 2 O 6 The material is distinguished in that it has not been subjected to an amorphization treatment.
Comparative example 14
As in example 11, li is selected 4 GeO 4 The material is distinguished in that it has not been subjected to an amorphization treatment.
TEM characterization
The products obtained in examples 1 to 11 and comparative examples 1 to 14 were subjected to TEM test to verify the degree of amorphization thereof. In the process of measuring the thickness of the surface layer of the amorphous oxygen-containing solid electrolyte, the specific test method is as follows: and selecting the surface layer of the amorphous oxygen-containing solid electrolyte, measuring 5 thickness data values, and taking an average value. Recorded in table 1. Fig. 2 is a TEM image of the surface layer amorphous oxygen-containing solid electrolyte obtained in example 1, and according to the test result, the surface layer thickness of the amorphous oxygen-containing solid electrolyte in example 1 is 6nm. Fig. 3 is a TEM image of the crystalline oxygen-containing solid electrolyte obtained in comparative example 1, and according to the test result, the oxygen-containing solid electrolyte material in comparative example 1 has no amorphous oxygen-containing solid electrolyte surface layer, and thus the thickness of the amorphous oxygen-containing solid electrolyte surface layer is 0nm. Fig. 4 is a TEM image of the fully amorphous oxygen-containing solid electrolyte obtained in comparative example 2, and according to the test result, the oxygen-containing solid electrolyte material in comparative example 2 has been fully amorphous, and the thickness of the amorphous oxygen-containing solid electrolyte surface layer is greater than 50nm.
Table 1 below shows thickness data of the amorphous layers (i.e., amorphous oxygen-containing solid electrolyte surface layers) measured by TEM test of examples 1 to 11 and comparative examples 1 to 14.
TABLE 1
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From example 1 to example 6, according to the results of table 1, the thickness of the amorphous layer increased with the increase in the content of the pretreatment agent and the amorphous additive and the increase in the polishing time. From a comparison of example 1 with comparative example 1, it was found that the same oxygen-containing solid electrolyte did not exhibit an amorphous layer without the addition of the pretreatment agent and the amorphous additive. By comparing example 1 with comparative examples 3 to 5, it was found that the amorphous oxygen-containing solid electrolyte could not be obtained by adding only the pretreatment agent, no amorphous additive, or no pretreatment agent, and only the amorphous additive. By comparing example 1 with comparative example 2, it was found that the addition of an excessive amount of the pretreatment agent resulted in a completely amorphous oxygen-containing solid electrolyte. The thickness of the amorphous layer of the oxygen-containing solid electrolyte material can be controlled by the technology of the invention.
It is to be noted that examples 7 to 11 do not belong to the same type of solid state electrolyte as the NASICON type solid state electrolyte, and therefore the hardness and surface properties of the materials are different. And thus cannot be compared during the amorphization treatment.
Application-cathode coating
Testing the electrochemical performance of the coated anode
TABLE 2
Group of Capacity retention rate (%) Capacity retention rate (%)
Example 1 92.3 88.2
Example 2 91.7 87.1
Example 3 92.2 88.4
Example 4 91.5 87.3
Example 5 91.4 86.8
Example 6 92.2 87.6
Example 7 92.1 87.5
Example 8 93.2 88.3
Example 9 91.4 87.1
Example 10 92.8 88.1
Example 11 93.0 87.1
Comparative example 1 83.4 74.3
Comparative example 2 84.2 73.2
Comparative example 6 82.8 70.4
Comparative example 7 78.8 70.2
Comparative example 8 83.5 72.8
Comparative example 9 77.3 69.7
Comparative example 10 75.8 67.3
Comparative example 11 81.2 71.4
Comparative example 12 80.4 70.1
Comparative example 13 75.1 66.4
Comparative example 14 74.3 61.4
As can be seen from the data in table 2, the surface amorphous oxygen-containing solid electrolyte prepared by the invention is applied to the positive electrode coating, and has better performance in cycle performance and rate performance than the crystalline and completely amorphous oxygen-containing solid electrolyte coating. The amorphous surface layer of the oxygen-containing solid electrolyte with the amorphous surface layer has flexibility, can be well infiltrated with electrolyte, reduces the solid-liquid interface resistance, realizes the rapid transmission of lithium ions, and is superior to crystalline oxygen-containing solid electrolyte; the crystalline structure inside the lithium ion battery has a stable lithium ion transmission path, so that the lithium ion battery can provide higher ion conductivity than an amorphous state, and meanwhile, the direct contact between the positive electrode material and electrolyte can be avoided, and the stability of the positive electrode material is improved. And thus also in combination is superior to fully amorphized oxygen-containing solid electrolytes.
Application-diaphragm coating
The electrochemical properties of the coated separator were tested and the test results are shown in table 3.
TABLE 3 Table 3
From the data, the amorphous oxygen-containing solid electrolyte on the surface layer prepared by the invention is applied to diaphragm coating, and compared with the crystalline and completely amorphous oxygen-containing solid electrolyte for diaphragm coating, the lithium battery has better performance in cycle performance and rate performance. The oxygen-containing solid electrolyte with the amorphous surface layer prepared in the embodiment can fully infiltrate electrolyte because the surface layer is in an amorphous state after the membrane is coated with the oxygen-containing solid electrolyte, so that lithium ions in the electrolyte can conveniently pass through the membrane directly or through the oxygen-containing solid electrolyte layer and then pass through the membrane, the internal resistance of the battery is effectively reduced, and the improvement of the cycle and the rate performance is realized. The crystalline oxygen-containing solid electrolyte has poor wettability with the electrolyte, and the completely amorphous oxygen-containing solid electrolyte has low lithium ion conductivity. In combination, crystalline oxygen-containing solid electrolytes and fully amorphous oxygen-containing solid electrolytes are less effective than surface amorphous solid electrolytes in membrane coating applications.
application-Pole piece blending
The electrochemical properties of the blended pole pieces were tested and the test results are shown in table 4 below.
TABLE 4 Table 4
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As can be seen from the data in Table 4 above, the electrode sheet prepared by using the surface layer amorphous oxygen-containing solid electrolyte prepared by the invention as the positive electrode blending additive has better performance in both cycle performance and rate performance compared with the crystalline and completely amorphous oxygen-containing solid electrolyte. The mixed surface layer amorphized oxygen-containing solid electrolyte is filled in gaps of the positive electrode active material, the amorphized surface layer has flexibility, can be well infiltrated with electrolyte, and greatly improves the liquid absorption rate of the pole piece, thereby reducing the solid-liquid interface resistance, realizing the full and rapid transmission of lithium ions, improving the capacity and service life of the battery, and being superior to crystalline oxygen-containing solid electrolyte. However, after the fully amorphous oxygen-containing solid electrolyte is mixed, although the wettability of the electrolyte can be improved, the lithium ion conductivity is low, the lithium ion transmission is blocked, and the corresponding cycle and rate performance of the battery are inferior to those of the oxygen-containing solid electrolyte with the amorphous surface layer. Note that in comparative example 6, the amorphous layer had a thickness of only 3nm, not in the range of 5 to 50nm, and the wettability with the electrolyte was poor, resulting in poor capacity retention of the battery. In comparative examples 7 to 9, the amorphous layer exceeding 50nm affects the transport of lithium ions in the solid electrolyte, resulting in poor performance of the battery.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (14)

1. A surface amorphous oxygen-containing solid electrolyte comprising a crystalline oxygen-containing solid electrolyte body and an amorphous oxygen-containing solid electrolyte surface in-situ contact with the crystalline oxygen-containing solid electrolyte body.
2. The surface amorphous oxygen-containing solid electrolyte according to claim 1, wherein the crystalline oxygen-containing solid electrolyte body has a particle size of 100 to 500nm;
the thickness of the surface layer of the amorphous oxygen-containing solid electrolyte is 5-50 nm.
3. The surface amorphous oxygen-containing solid electrolyte of claim 1, wherein the crystalline oxygen-containing solid electrolyte body is selected from the group consisting of:
Li 4 XO 4 Si, ge, ti, zr or Li 3 YO 4 Wherein X is at least one of Si, ge, ti or Zr, and Y is at least one of P, as, V, nb or Ta;
or (b)
Li 1+x+3y A x B 2-x (P 1-y Si y O 4 ) 3 、Li 1+x+3y C x B 2-1.5x (P 1-y Si y O 4 ) 3 Or Li (lithium) 1+x+3y D x B 2-1.75x (P 1-y Si y O 4 ) 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein a is at least one of Al, fe, sc, lu, Y, la, cr, ga or In; b is at least one of Ti, ge, zr, hf or Sn; c is at least one of V, nb or Ta; d is at least one of Mo or W; x is more than 0 and less than 0.6,0, y is more than or equal to 0.6;
or (b)
Li 1+x H 1-x Al(PO 4 )O 1-y M 2y Wherein 0.ltoreq.x<1，0<y<0.1, M is F, cl, br or I
At least one of (a) and (b);
or (b)
Li x A’ 3 B’ 2 O 12 The method comprises the steps of carrying out a first treatment on the surface of the Wherein A' is at least one of La, nb, mg, ba, ca or Sr; b' is at least one of Te, ta, nb, zr or In; x is more than 0 and less than or equal to 7;
or (b)
Li 3x La 2/3-x TiO 3 ；0＜x≤2/3；
Or (b)
Li 3 OX’、Li 3-2x A” x B”O、Li 1.9 OHCl 0.9 Or Li (lithium) 2 At least one of OHCl; wherein X' is at least one of F, cl, br or I; a' is at least one of Mg, ca, sr or Ba; b' is Cl and/or I; x is more than or equal to 0 and less than 3/2;
or (b)
Li 3 AlSiO 5 、LiAlSi 2 O 6 、LiAlSi 4 O 10 、LiAlSi 2 O 6 Or LiAlSiO 4 At least one of them.
4. A method for producing the surface-layer-amorphized oxygen-containing solid electrolyte according to any one of claims 1 to 3, comprising the steps of:
s1: mixing crystalline oxygen-containing solid electrolyte body particles with a solvent, and performing first sanding treatment to obtain submicron crystalline oxygen-containing solid electrolyte body slurry;
S2: pretreating the submicron crystalline oxygen-containing solid electrolyte bulk slurry under the action of a pretreatment agent;
s3: and mixing the pretreated crystalline oxygen-containing solid electrolyte slurry body with an amorphous additive, and performing second sanding treatment to obtain the surface amorphous oxygen-containing solid electrolyte.
5. The method according to claim 4, wherein the pretreatment agent in step S2 is any one or more of oxalic acid, citric acid, pyruvic acid, acetic acid, salicylic acid, and phenylglycolic acid;
the addition amount of the pretreatment agent is 0.1-10wt% of the mass of the crystalline oxygen-containing solid electrolyte body particles.
6. The method according to claim 4, wherein the pretreatment in step S2 is specifically: the pretreatment agent is added into submicron crystalline oxygen-containing solid electrolyte body slurry, and stirring and homogenizing treatment is carried out for 1-5 h at 100-300 rpm.
7. The method according to claim 4, wherein the amorphous additive is selected from any one or more of amorphous aluminum oxide, amorphous silicon oxide, amorphous titanium oxide, and amorphous zirconium oxide;
the average particle diameter of the amorphous additive is 10-50 nm.
8. The method of claim 4, wherein the amorphous additive is present in the form of an amorphous additive suspension;
the amorphous additive suspension is obtained by mixing and dispersing an amorphous additive and a suspension medium;
the suspension medium and the solvent in the submicron crystalline oxygen-containing solid electrolyte slurry are the same material.
9. The method according to claim 8, wherein the amorphous additive suspension is added in an amount of 10 to 30wt% based on the mass of the submicron crystalline oxygen-containing solid electrolyte bulk slurry.
10. The method according to claim 8, wherein the mass ratio of the amorphous additive to the suspension medium in the amorphous additive suspension is 1:10 to 3.5:10.
11. The method according to claim 4, wherein the mass ratio of the solvent to the crystalline oxygen-containing solid electrolyte bulk particles is 2:1 to 5:1;
the solvent is selected from any one or more of deionized water, absolute ethyl alcohol, isopropanol or N-methyl pyrrolidone.
12. The method of manufacturing according to claim 4, wherein the first sanding treatment is performed in the presence of a first abrasive ball;
The mass ratio of the crystalline oxygen-containing solid electrolyte body particles to the first grinding balls is 1 (5-20);
the second sanding treatment is performed in the presence of a second abrasive ball;
the mass ratio of the crystalline oxygen-containing solid electrolyte body particles to the second grinding balls is 1 (5-20);
the first grinding balls and the second grinding balls are respectively and independently selected from zirconia balls, alumina balls or agate balls, and the diameters of the first grinding balls and the second grinding balls are respectively and independently selected from 0.1-0.6 mm;
the linear speeds of the first sanding treatment and the second sanding treatment are respectively and independently selected from 15-25 m/s.
13. The method according to claim 4, wherein the first sanding treatment in step S1 is performed for 8 to 24 hours;
and (3) the time of the second sanding treatment in the step (S3) is 1-5 h.
14. Use of the surface-layer-amorphized oxygen-containing solid electrolyte according to any one of claims 1 to 3 or the surface-layer-amorphized oxygen-containing solid electrolyte prepared according to the preparation method of any one of claims 4 to 13 in positive electrode coating, separator coating or pole piece blending.
CN202311670149.6A 2023-12-06 2023-12-06 Surface amorphous oxygen-containing solid electrolyte and preparation method and application thereof Pending CN117712468A (en)

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