CN116315052A

CN116315052A - Solid electrolyte material, preparation method and electrode

Info

Publication number: CN116315052A
Application number: CN202310291415.8A
Authority: CN
Inventors: 张雪; 冯玉川; 张苗; 李峥
Original assignee: Suzhou Qingtao New Energy S&T Co Ltd
Current assignee: Suzhou Qingtao New Energy S&T Co Ltd
Priority date: 2023-03-23
Filing date: 2023-03-23
Publication date: 2023-06-23

Abstract

The application provides a solid electrolyte material, a preparation method, an electrode and a lithium ion battery, wherein the solid electrolyte material comprises a halide solid electrolyte, and the chemical general formula of the halide solid electrolyte is as follows: li (Li) _2+a‑b Zr _1‑a‑b A _a BbX ₆ Wherein, the element A is at least one of 3 valence metal elements, the element B is at least one of 5 valence tantalum or niobium, the element X is at least one of F, cl, br, I, the value range of 2+a-B is 1.85-2.45, preferably 2.0-2.3, the value range of a+b is 0.1-0.5, the value range of a/B is 0.5-3.5, and the ratio of the element A to the element B to Li is equal to or higher than that of the element B ₂ ZrCl ₆ According to the standard structure of the solid electrolyte, the microstructure in the prepared halide solid electrolyte is regulated and controlled by doping A, B elements of proper types, and the migration barrier of lithium ions in the solid electrolyte is reduced, so that the ion conductivity of the solid electrolyte is increased.

Description

Solid electrolyte material, preparation method and electrode

Technical Field

The application relates to the technical field of batteries, in particular to a solid electrolyte material, a preparation method and an electrode.

Background

With the increasing exhaustion of fossil energy and the increasing prominence of environmental protection, new energy sources represented by lithium ions are considered as an important means for solving the current energy sources. However, the safety of the traditional liquid lithium ion battery cannot meet the increasingly severe use requirements due to the use of flammable and explosive and toxic electrolyte; and its energy density approaches the process limit. Solid state batteries using a solid state electrolyte instead of a separator and an electrolyte in conventional lithium ion batteries are currently recognized as a new battery technology of the next generation, and solid state electrolyte materials are core technologies of solid state batteries.

The existing solid electrolyte materials mainly comprise polymer solid electrolyte, sulfide solid electrolyte, oxide solid electrolyte and the like, and the materials have respective advantages and disadvantages. For example, sulfide solid-state electrolytes, though having higher ionic conductivity, are too sensitive to moisture and air, and have high preparation cost and great industrialization difficulty; the oxide solid electrolyte has simple preparation process and easy industrialization, but has poor interface performance with the anode and the cathode, and influences the overall performance of the battery.

Compared with oxide solid electrolytes and sulfide solid electrolytes, halide solid electrolytes are an emerging class of ceramic materials that are of interest due to their outstanding combination of advantages in terms of conductivity, pressure resistance, mechanical suitability, environmental stability, cost, etc. For ceramic materials, doping is currently considered as an important method for improving the material performance, and the doping method is divided into homovalent doping and heterovalent doping, wherein homovalent doping is generally used for adjusting the bonding energy between ions; while heterovalent doping can introduce some defects in the material structure, or change the concentration of carriers (such as lithium ions) or change the microstructure, mainly in some barrier values. However, the above doping theory is only a theoretical presumption, and many unexpected effects are often generated for different material systems. Li (Li) ₂ ZrCl ₆ Due to its low cost and combination of properties, it is of interest to researchers for halide solid state electrolytes. For Li ₂ ZrCl ₆ In other words, patent document CN112204675B discloses a halide solid electrolyte having the chemical structural formula of Li _6-4a M _a X ₆ WhereinM is selected from IVB group elements of Zr, hf and Ti, and the data in the examples also realize the different performances of the elements such as Zr, hf and the like under the conditions of different doping and different proportions; the applicant has confirmed in previous studies that specific 3+ lanthanoid elements such as Eu, gd are doped with Li ₂ ZrCl ₆ Has a different structure and higher ion conductivity than other element doping. This doping effect exhibits a personalized character and is therefore specific to Li ₂ ZrCl ₆ It is necessary to develop materials and doping methods that are more targeted.

Disclosure of Invention

In order to solve one or more of the above technical problems in the prior art, embodiments of the present application provide a solid electrolyte material, a preparation method, and an electrode, so as to solve the contradictory relationship between the performance and cost of the current halide solid electrolyte, and prepare a solid electrolyte material with lower cost and higher ionic conductivity.

In order to achieve the above purpose, the technical scheme adopted by the application for solving the technical problems is as follows:

in a first aspect, the present application provides a solid state electrolyte material comprising a halide solid state electrolyte having the chemical formula: li (Li) _2+a-b Zr _1-a-b A _a B _b X ₆ ；

Wherein the valence state of the element A is 3;

the valence state of the element B is 5;

element X is at least one of F, cl, br, I;

2+a-b has a value in the range of 1.85-2.45, preferably 2.0-2.3;

the value of a+b ranges from 0.1 to 0.5, and the value of a/b ranges from 0.5 to 3.5, preferably from 1 to 3.

Preferably, element A is Ga3 ⁺ 、In ³⁺ 、Al ³⁺ 、Fe ³⁺ 、Y ³⁺ 、Bi ³⁺ At least one of +3 valent lanthanide metals.

Further preferably, the element A has an average ionic radius value of preferably 90-95pm.

It will be appreciated that when element a is a mixture of elements, for example: A1A 1 _al A2 _a2 ......An _an The average ionic radius value is

Preferably, element B is a niobium element.

In a specific embodiment, the concentration of the element B in the halide solid state electrolyte is less than the concentration of the element a.

In a specific embodiment, the element X is a mixture, the element X contains Cl, and the molar ratio of the Cl element in the element X ranges from 80% to 99.99%, preferably, the molar ratio of the Cl element in the element X ranges from 83% to 96%.

In a specific embodiment, the halide solid state electrolyte is in the form of any one of a glassy phase, a glass-ceramic phase, or a crystalline phase.

In a specific embodiment, the solid electrolyte material comprises only the halide solid electrolyte or is composed of the halide solid electrolyte main component.

In a second aspect, corresponding to the above-mentioned halide solid electrolyte, the present application also provides a method for preparing a halide solid electrolyte, the method comprising:

mixing lithium salt, zirconium salt, salt corresponding to element A and salt corresponding to element B in a mixing device according to a preset stoichiometric ratio to obtain an intermediate;

sintering the intermediate to obtain the halide solid electrolyte.

Preferably, the mixing device is a ball milling tank;

further preferably, the mixing device is ZrO ₂ Ball milling jar.

Preferably, the ball milling speed of the ball milling tank is 200-800 rpm, and the ball milling time is 10-50h.

Preferably, the sintering temperature is 150-350 ℃.

Preferably, the sintering time is 0-40h.

In a third aspect, corresponding to the above solid electrolyte material, there is also provided an electrode comprising the solid electrolyte material as described above.

In a specific embodiment, the electrode comprises an active material layer comprising a solid electrolyte layer comprising the solid electrolyte material.

In a specific embodiment, the solid state electrolyte layer is composed of a composite solid state electrolyte comprising the halide solid state electrolyte.

Preferably, the halide solid electrolyte comprises 1 to 99.99wt% of the mass of the solid electrolyte layer.

In a specific embodiment, the solid state electrolyte layer has a thickness of 0.1 to 100 microns; preferably, the solid electrolyte layer has a thickness of 1 to 20 micrometers.

In a specific embodiment, the electrode includes a positive electrode, and the active material layer includes a positive electrode active material layer.

In a specific embodiment, the electrode comprises a negative electrode and the active material layer comprises a negative electrode active material layer.

In a fourth aspect, corresponding to the above solid electrolyte material, there is also provided a lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte comprising at least the solid electrolyte material as described above.

The beneficial effects that technical scheme that this application embodiment provided brought are:

the solid electrolyte material, the preparation method, the electrode and the lithium ion battery provided by the embodiment of the application comprise halide solid electrolyte, and compared with Li ₂ ZrCl ₆ By doping 3-valent and 5-valent elements of proper types, the lithium ion concentration can be accurately regulated and controlled, the microstructure is modified, and the comprehensive performance of the halide solid electrolyte is surprisingly improved; in particular, it isWhen the element of valence 5 is niobium (Nb), nb is the cause of ⁵⁺ D-orbital electron in the electron structure of (2) is 0, referring to Li rich in lithium _1.25 Nb _0.25 Mn _0.5 O ₂ (electrochem. Commun.60, 70) and Li _1.3 Nb _0.3+x M _0.4-x O ₂ (m=mn, fe, co, ni) (proc.Natl. Acad.Sci.U.S. A.112, 7650), the metal ion of the d0 structure can stabilize the disorder of the cation, when it is matched with trivalent elements, it can achieve more excellent effect, only as a guess and not limit the protection scope, after Nb of the d0 structure is introduced, the local disorder of the Li2ZrCl6 structure is improved on the basis of 3-valence doping, the property is similar to the inorganic matter of Garnet, NASICON structure (Zeng et al, science 378, 1320-1324 (2022)), the local disorder structure can reduce the lithium ion migration barrier and accelerate the diffusion, thereby improving the lithium ion transmission performance.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is an impedance plot of a halide solid state electrolyte provided in example 3 of the present application;

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the present application more apparent, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

The following specifically describes schemes provided in the embodiments of the present application with reference to the accompanying drawings.

As described in the background of the invention section,such as Li ₃ InCl ₆ For this problem, a halide solid electrolyte mainly composed of Zr has been proposed, which is produced at high cost due to the use of a large amount of rare earth elements. However, the pure solid state halide electrolyte mainly comprising 4-valent zirconium has limited performance improvement, and the technical problem that the comprehensive performance of the solid state halide electrolyte cannot meet the actual use requirement cannot be effectively solved.

To address one or more of the problems described above, the present application creatively proposes a new solid electrolyte material comprising a halide solid electrolyte having the chemical formula: li (Li) _2+a-b Zr _1-a- _b A _a B _b X ₆ Wherein the valence state of the element A is +3, the valence state of the element B is +5, and the valence state of the element X is at least one of F, cl, br, I.

For Li ₂ ZrCl ₆ According to the standard structure of (2) the stoichiometric ratio of lithium element in the prepared halide solid electrolyte can be accurately regulated and controlled within a certain range by doping A, B element of a proper type, and the electrolyte can show excellent ion conductivity by matching with the regulation of microstructure, a small amount of lithium deficiency or increasing the concentration of lithium within a certain range, but the content of lithium element is too high or too low, so that negative effects can be brought, therefore, the embodiment of the application further limits that the 2+a-b has the value range of 1.85-2.45, preferably 2.0-2.3, the value range of a+b is 0.1-0.5, and the value range of a/b is 0.5-3.5, preferably 1-3.

It is understood that the element represented by A is +3 valent in the chemical formula, the element represented by B is +5 valent in the chemical formula, and the halogen element represented by X is-1 valent in the chemical formula. The lanthanum (La) group metals of the present invention include, but are not limited to, la (lanthanum), ce (cerium), pr (praseodymium), nd (neodymium), pm (promethium), sm (samarium), eu (europium), gd (gadolinium), tb (terbium), dy (dysprosium), ho (holmium), er (erbium), tm (thulium), yb (ytterbium), lu (lutetium).

Preferably, the element A is Ga3 ⁺ 、In ³⁺ 、Al ³⁺ 、Fe ³⁺ 、Y ³⁺ 、Bi ³⁺ +3 valent lanthanoidOne or more of the metals.

It will be appreciated that when a is a mixture of elements, for example: A1A 1 _a1 A2 _a2 ......An _an The average ionic radius value is

Preferably, element B is niobium.

Due to the special outermost electronic structure (d) of niobium in the halide solid electrolyte ⁰ ) Doping of niobium at 5-valence improves doped Li2ZrCl at 3-valence ₆ The degree of disorder of the solid electrolyte is improved, and the ion conductivity of the solid electrolyte is further improved.

The doping method is particularly suitable for Li which takes Zr as a main element ₂ ZrCl ₆ A material.

In some specific embodiments, the element X is one of F, cl, br, I.

In other specific embodiments, the element X is a mixture of two or more F, cl, br, I.

In the embodiment of the application, the solid electrolyte containing the zirconium element is co-doped with the +3 valent element and the +5 valent niobium element, so that the ionic conductivity of the halide electrolyte at room temperature can be effectively improved, and the overall performance of the electrolyte material is improved.

Preferably, the halide solid electrolyte is in any one of a glass phase, a glass-ceramic phase, or a crystalline phase.

Preferably, the solid electrolyte material is composed of only a halide solid electrolyte or is composed of a halide solid electrolyte as a main component.

In a second aspect, the present application also provides a method for preparing the above-mentioned halide solid electrolyte, the method comprising:

s1: mixing lithium salt, zirconium salt, salt corresponding to element A and salt corresponding to element B in a mixing device according to a preset stoichiometric ratio to obtain an intermediate product;

s2: sintering the intermediate product to obtain the halide solid electrolyte.

Preferably, the mixing device in step S1 is a ball milling tank;

further preferably, the mixing device in step S1 is ZrO ₂ Ball milling jar.

Preferably, the sintering temperature is 150-350 ℃.

Preferably, the sintering time is 0-40h.

In a preferred embodiment, the lithium and zirconium salts referred to in step S1 are lithium and zirconium halides, so as not to synthesize Li _2+a-b Zr _1-a-b A _a B _b X ₆ Other impurities are introduced in the halide solid state electrolyte that affect the structure and properties of the final product.

Corresponding to the above solid electrolyte material, the present application also provides an electrode comprising the solid electrolyte material as described above.

In some specific embodiments, the electrode includes an active material layer comprising a solid electrolyte layer comprising the solid electrolyte material.

Preferably, the solid electrolyte layer comprises only the halide solid electrolyte, i.e. the solid electrolyte material consists of only halide solid electrolyte.

Further preferably, the solid electrolyte layer comprises two or more of the halide solid electrolytes.

It will be appreciated that each of the above two or more halide solid electrolytes is selected from the halide solid electrolytes described in the first aspect, i.e. the solid electrolyte layer consists only of the halide solid electrolyte material referred to in the present application.

In some specific embodiments, the solid state electrolyte layer is comprised of a composite solid state electrolyte comprising the halide solid state electrolyte.

It is understood that a composite solid electrolyte refers to a solid electrolyte member composed of two or more solid electrolyte materials, and a composite solid electrolyte in the present application may be understood as a solid electrolyte material composed of a halide solid electrolyte in the present application and other kinds of solid electrolytes. The present application is not particularly limited to the kinds of other kinds of solid electrolytes, and any known solid electrolyte kinds can be used in the present application without departing from the inventive concept of the present application, including but not limited to oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, hydride solid electrolytes, boride solid electrolytes, nitride solid electrolytes, polymer solid electrolytes, and the like.

As an embodiment, the oxide solid electrolyte may comprise one or more garnet ceramics, LIS ICON-type oxides, NASICON-type oxides, and perovskite-type ceramics. For example, the one or more garnet ceramics may be selected from the group consisting of: li (Li) _6.5 La ₃ Zr _1.75 Te _0.25 O ₁₂ 、Li ₇ La ₃ Zr ₂ O ₁₂ 、Li _6.2 Ga _0.3 La _2.9 Rb _0.05 Zr ₂ O ₁₂ 、Li _6.85 La _2.9 Ca _0.1 Zr _1.75 Nb _0.25 O ₁₂ 、Li _6.25 Al _0.25 La ₃ Zr ₂ O ₁₂ 、Li _6.75 La ₃ Zr _1.75 Nb _0.25 O ₁₂ And combinations thereof. The one or more LI SICON-type oxides may be selected from the group comprising: li (Li) ₁₄ Zn(GeO ₄ ) ₄ 、Li _3+x (P _1-x Si _x )O ₄ (wherein x is more than or equal to 0 and less than 1), li _3+x Ge _x V _1-x O ₄ (wherein 0 < x < 1) and combinations thereof. One or more NASICON-type oxides may be formed from LiMM' (PO ₄ ) ₃ And a definition wherein M and M' are independently selected from Al, ge, ti, sn, hf, zr and La. For example, in some variations, one ofOr a plurality of NASICON-type oxides may be selected from the group comprising: li (Li) _1+x Al _x Ge _2-x (PO ₄ ) ₃ (LAGP) (wherein 0.ltoreq.x.ltoreq.2), li _1+x Al _x Ti _2-x (PO ₄ ) ₃ (LATP) (where 0.ltoreq.x.ltoreq.2), li _1+x Y _x Zr _2-x (PO ₄ ) ₃ (LYZP) (wherein 0.ltoreq.x.ltoreq.2), li _1.a Al _0.3 Ti _1.7 (PO ₄ ) ₃ 、LiTi ₂ (PO ₄ ) ₃ 、LiGeTi(PO ₄ ) ₃ 、LiGe ₂ (PO ₄ ) ₃ 、LiHr ₂ (PO ₄ ) ₃ And combinations thereof. The one or more perovskite ceramics may be selected from the group comprising: li (Li) _3.3 La _0.53 TiO ₃ 、LiSr _1.65 Zr _1.3 Ta _1.7 O ₉ 、Li _2x-y Sr _1-x Ta _y Zr _1-y O ₃ (where x=0.75 y and 0.60 < y < 0.75), li _3/8 Sr _7/16 Nb _3/ ₄ Zr _1/4 O ₃ 、

(wherein 0 < x < 0.25) and combinations thereof. In one variation, the one or more oxide-based materials may have a weight of greater than or equal to about 10 ^-5 S/cm to less than or equal to about 10 ^-1 S/cm ionic conductivity.

As an embodiment, the sulfide solid state electrolyte may include one or more sulfide-based materials selected from the group consisting of: li (Li) ₂ S-P ₂ S ₅ 、Li ₂ S-P ₂ S ₅ -MS _x (wherein M is Si, ge and Sn and 0.ltoreq.x.ltoreq.2), li _3.4 Si _0.4 P ₀ . ₆ S ₄ 、Li ₁₀ GeP ₂ S _11.700.3 、Li _9.6 P ₃ S ₁₂ 、Li ₇ P ₃ S ₁₁ 、Li ₉ P ₃ S ₉ O ₃ 、Li _10.35 Si _1.35 P ₁ . ₆₅ S ₁₂ 、Li _9.81 Sn _0.81 P _2.19 S ₁₂ 、Li ₁₀ (Si _0.5 Ge _0.5 )P ₂ S ₁₂ 、Li(Ge _0.5 Sn _0.5 )P ₂ S ₁₂ 、Li(Si _0.5 Sn _0.5 )PsS ₁₂ 、Li _1o GeP ₂ S ₁₂ (LGPS)、Li ₆ PS ₅ X (wherein X is Cl, br or I), li ₇ P ₂ S ₈ I、Li _10.35 Ge _1.a5 P _1.65 S ₁₂ 、Li _3.25 6e _0.25 P _0.75 S ₄ 、Li _1o SnP ₂ S ₁₂ 、Li ₁₀ SiP ₂ S ₁₂ 、Li _9.54 Si _1.74 P _1.44 S _11.7 Cl _0.3 、(1-x)P ₂ S _5-x Li ₂ S (wherein 0.5.ltoreq.x.ltoreq.0.7) and combinations thereof. In one variation, the one or more sulfide-based materials may have a composition of greater than or equal to about 10 ^-7 An ion conductivity of from S/cm to less than or equal to about 1S/cm.

As an embodiment, the halide solid state electrolyte may include one or more halide-based materials selected from the group consisting of: li (Li) ₂ CdCl ₄ 、Li ₂ MgCl ₄ 、Li ₂ CdI ₄ 、Li ₂ ZnI ₄ 、Li ₃ OCl、LiI、Li ₅ ZnI ₄ 、Li ₃ OCl _1-x Br _x (wherein 0 < x < 1) and combinations thereof. In one variation, the one or more halide-based materials may have a weight ratio of greater than or equal to about 10 ^-8 S/cm to less than or equal to about 10 ^-1 S/cm ionic conductivity.

As an embodiment, the borate solid state electrolyte may include one or more borate-based materials selected from the group consisting of: li (Li) ₂ B ₄ O ₇ 、Li ₂ O-(B ₂ O ₃ )-(P ₂ O ₅ ) And combinations thereof. In one variation, the one or more borate-based materials may have a weight ratio of greater than or equal to about 10 ^-7 S/cm to less than or equal to about 10 ^-2 S/cm ionic conductivity.

As an embodiment, the nitride solid state electrolyte may include one or more nitride-based materials selected from the group consisting of: li (Li) ₃ N、Li ₇ PN ₄ 、LiSi ₂ N ₃ And combinations thereof. In one variation, the one or more nitride-based materials may have a composition greater than or equal to about 10 ^-9 An ion conductivity of from S/cm to less than or equal to about 1S/cm.

As an embodiment, the hydride solid state electrolyte may comprise one or more hydride-based materials selected from the group consisting of: li (Li) ₃ AlH ₆ 、LiBH ₄ 、LiBH ₄ -LiX (wherein X is one of Cl, br and I), liNH ₂ 、Li ₂ NH、LiBH ₄ -LiNH ₂ And combinations thereof. In one variation, the one or more hydride-based materials can have a composition of greater than or equal to about 10 ^-7 S/cm to less than or equal to about 10 ^-2 S/cm ionic conductivity.

The thickness of the solid electrolyte layer is not particularly limited, and the thickness of the solid electrolyte layer can be adjusted as necessary on the basis of not departing from the inventive concept of the present application, and it is understood that conventional adjustment of the thickness of the solid electrolyte layer falls within the scope of protection of the present application.

By way of illustrative example only, and not limitation of the scope of protection, the solid electrolyte layer has a thickness of 0.1-100 microns; preferably, the solid electrolyte layer has a thickness of 1 to 20 micrometers.

In some specific embodiments, the electrode includes a positive electrode, and the active material layer includes a positive electrode active material layer.

In some specific embodiments, the electrode comprises a negative electrode and the active material layer comprises a negative electrode active material layer.

It is known in the art to provide a solid electrolyte layer on the surface of a positive electrode active material layer to improve the safety of a battery. The solid electrolyte layer is different from a solid electrolyte membrane which plays an electronic insulation role between a positive electrode and a negative electrode, and the main purpose of the solid electrolyte layer is to prevent side reactions of the positive electrode material; meanwhile, the solid electrolyte layer improves the internal resistance of the battery to some extent.

It is understood that the positive electrode active material layer contains a positive electrode active material, and the negative electrode active material layer contains a negative electrode active material. The present embodiment is not particularly limited to the positive electrode active material and the negative electrode active material, and any known types of positive electrode active material and negative electrode active material can be used in the present application without departing from the inventive concept of the present application, and the negative electrode active material may include a lithium-based negative electrode active material including, for example, lithium metal and/or lithium alloy, by way of illustrative example only, and not by way of any limitation of the scope of protection. In other embodiments, the anode may be a silicon-based anode active material comprising silicon, such as a silicon alloy, silicon oxide, or a combination thereof, which may also be mixed with graphite in some cases. In other embodiments, the anode active material may include a carbonaceous-based anode active material including one or more of graphite, graphene, carbon Nanotubes (CNTs), and combinations thereof. In still other embodiments, the negative electrode active material includes one or more negative electrode active materials that accept lithium, such as lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ) One or more transition metals (e.g., tin (Sn)), one or more metal oxides (e.g., vanadium oxide (V) ₂ O ₅ ) Tin oxide (SnO), titanium dioxide (TiO) ₂ ) Titanium niobium oxide (TixNbyOz, where 0.ltoreq.x.ltoreq.2, 0.ltoreq.y.ltoreq.24, and 0.ltoreq.z.ltoreq.64), metal alloys (such as copper-tin alloys (Cu) ₆ Sn ₅ ) And one or more metal sulfides such as iron sulfide (FeS), etc.

The positive electrode active material may be one of a layered oxide cathode, a spinel cathode, and a polyanion cathode. For example, a layered oxide cathode (e.g., a rock salt layered oxide) comprises one or more lithium-based positive electroactive materials selected from the group consisting of: liCoO ₂ (LCO)，LiNi _x Mn _y Co _1-x-y O ₂ (wherein x is more than or equal to 0 and less than or equal to 1, and y is more than or equal to 0 and less than or equal to 1), and LiNi1 _-x-y Co _x Al _y O ₂ (wherein x is more than or equal to 0 and less than or equal to 1, and y is more than or equal to 0 and less than or equal to 1), and LiNi _x Mn _1-x O ₂ (wherein 0.ltoreq.x.ltoreq.1), and Li _1+x MO ₂ (wherein M is one of Mn, ni, co and Al and 0.ltoreq.x.ltoreq.1). The spinel cathode comprises one or more lithium-based positive electroactive materials selected from the group consisting of: liMn ₂ O ₄ (LMO) and LiNi _x Mn _1.5 O ₄ . Olivine-type cathodes comprising one or more lithium-based positive electroactive materials LiMPO ₄ (wherein M is at least one of Fe, ni, co and Mn). The polyanionic cation comprises, for example, a phosphate such as LiV ₂ (PO ₄ ) ₃ And/or silicates such as life io ₄ 。

The positive and negative electrode active materials may be optionally mixed with a binder including, but not limited to, polytetrafluoroethylene (PTFE), sodium carboxymethylcellulose (CMC), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), nitrile rubber (NBR), styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-butadiene-styrene copolymer (SBS), lithium polyacrylate (LiPAA), sodium polyacrylate (NaPAA), sodium alginate, lithium alginate, or a combination thereof. Meanwhile, the positive electrode active material layer and the negative electrode active material layer may optionally be added with a conductive agent to provide a conductive path, and the conductive agent may include a carbon-based material, powdered nickel or other metal particles, or a conductive polymer. Carbon-based materials may include, for example, carbon black, graphite, acetylene black (e.g., KETCHENTM black or denktatm black), carbon fibers and particles of nanotubes, graphene, and the like. Examples of the conductive polymer include polyaniline, polythiophene, polyacetylene, polypyrrole, and the like.

Corresponding to the above solid electrolyte material, the present application also provides a lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte comprising at least the solid electrolyte material as described above.

It is understood that the electrolyte may be composed of only the above solid electrolyte material, i.e., the lithium ion battery includes a positive electrode, a negative electrode, and a solid electrolyte material interposed between the positive electrode and the negative electrode, and functions to isolate the positive electrode from the negative electrode.

As a preferred embodiment, the electrolyte may also include other electrolyte materials.

It is understood that any suitable electrolyte capable of conducting lithium ions between the positive and negative electrodes may be used in the lithium ion battery, whether in solid, liquid, solid-liquid mixture, or gel form. The electrolyte system of the lithium ion battery is not particularly limited in this application, and any known electrolyte system may be applied to the lithium ion battery without departing from the inventive concept of the present application. Based on the understanding of the prior art, the solid-liquid mixed electrolyte system is used by mixing a nonaqueous electrolytic solution with a solid electrolyte, and the solid electrolyte system is composed of only the solid electrolyte. It should be understood that the solid electrolyte may be one solid electrolyte material, or may be two or more solid electrolyte materials, and the two or more solid electrolyte materials may be the same kind of solid electrolyte material, or may be different kinds of solid electrolyte materials.

In some specific embodiments, the electrolyte may be a non-aqueous electrolyte, and when the electrolyte is a non-aqueous electrolyte, the lithium ion battery further includes a separator, such as a separator or the like. The nonaqueous electrolytic solution includes a lithium salt dissolved in an organic solvent or a mixture of organic solvents. In certain variations, the separator may be formed of a microporous insulating material, wherein a liquid or semi-solid electrolyte is capable of being absorbed into the pores.

The organic solvent herein may use any organic solvent without particular limitation as long as it can serve as a medium through which ions participating in the electrochemical reaction of the battery can move. Specifically, as the organic solvent, ester solvents such as methyl acetate, ethyl acetate, γ -butyrolactone, and epsilon-caprolactone can be used; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents, such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; carbonate solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (MEC), ethylmethyl carbonate (EMC), ethylene Carbonate (EC) and Propylene Carbonate (PC); alcohol solvents such as ethanol and isopropanol; nitriles such as R-CN (wherein R is a linear, branched or cyclic C2-C20 hydrocarbon group and may contain a double bond aromatic ring or ether linkage); amides such as dimethylformamide; dioxolanes, such as 1, 3-dioxolane; or sulfolane.

The lithium salt herein may use any lithium salt without particular limitation as long as it can provide lithium ions used in a lithium secondary battery. Specifically, the inclusion points are not limited to lithium hexafluorophosphate (LiPF ₆ ) Lithium perchlorate (LiClO) ₄ ) Lithium tetrachloroaluminate (LiAlCl) ₄ ) Lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF) ₄ ) Lithium difluorooxalato borate (LiBF) ₂ (C ₂ O ₄ ) (LiODFB), lithium tetraphenylborate (LiB (C) ₆ H ₅ ) ₄ ) Lithium bis (oxalato) borate (LiB (C) ₂ O ₄ ) ₂ ) Lithium tetrafluorooxalate phosphate (LiPF) ₄ (C ₂ O ₄ ) (LiFeP), lithium nitrate (LiNO) ₃ ) Lithium hexafluoroarsenate (LiAsF) ₆ ) Lithium triflate (LiCF) ₃ SO ₃ ) Lithium bis (trifluoromethanesulfonyl imide) (LITFSI) (LiN (CF) ₃ SO ₂ ) ₂ ) Lithium bis (fluorosulfonyl imide) (LiN (FSO) ₂ ) ₂ ) (LIFSI) and combinations thereof. In certain variations, the lithium salt is selected from lithium hexafluorophosphate (LiPF ₆ ) Lithium bis (trifluoromethanesulfonyl imide) (LiTFSI) (LiN (CF) ₃ SO ₂ ) ₂ ) Lithium bis (fluorosulfonyl imide) (LiN (FSO) ₂ ) ₂ ) (LiFSI), lithium fluoroalkylphosphonate (LiFAP), lithium phosphate (Li) ₃ PO ₄ ) And combinations thereof, etc. may be used as the lithium salt. The lithium salt may be used at a concentration ranging from 0.1 to 2.0M, for example 0.1M, 0.3M, 0.5M, 0.7M, 0.8M, 1M, 1.2M, 1.3M, 1.5M, 1.6M, 1.8M, 2.0M, etc. When the concentration of the lithium salt is within the above range, the electrolyte has suitable conductivity and viscosity, thereby exhibiting excellent performance, and lithium ions can be effectively moved.

The solid electrolyte material can serve as both an ion conductor to transport and conduct lithium ions and an electrical insulator to prevent charge or current from flowing from the negative electrode to the positive electrode. Thus, the film of solid electrolyte material may replace the separator, and the related solid electrolyte materials are not particularly limited except for the halide solid electrolyte referred to herein, and any known solid electrolyte material can be used herein without departing from the inventive concept of the present application, including but not limited to oxide solid electrolyte, sulfide solid electrolyte, halide solid electrolyte, polymer solid electrolyte, nitride solid electrolyte, boride solid electrolyte, etc., and the related contents are not described in detail herein.

The present disclosure will be described in more detail with reference to the following examples.

Example 1

LiCl, zrCl ₄ 、InCl ₃ 、NbCl ₅ Adding the mixture to ZrO in a glove box in a molar ratio of 2:0.8:0.1:0.1 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained ₂ Zr _0.8 In _0.1 Nb _0.1 Cl ₆ . The ion conductivity of the electrolyte at room temperature was measured to be 0.566mS/cm.

Example 2

LiCl, zrCl ₄ 、LaCl ₃ 、NbCl ₅ Adding the mixture to ZrO in a glove box in a molar ratio of 2:0.8:0.1:0.1 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained ₂ Zr _0.8 La _0.1 Nb _0.1 Cl ₆ . The electrolyte obtained was found to have an ionic conductivity of 0.524mS/cm at room temperature.

Example 3

LiCl, zrCl ₄ 、DyCl ₃ 、NbCl ₅ Adding the mixture to ZrO in a glove box in a molar ratio of 2:0.8:0.1:0.1 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. ThenPutting the ball milling tank into a high-energy ball mill, and ball milling for 45 hours at a rotating speed of 530rpm to obtain Li ₂ Zr _0.8 Dy _0.1 Nb _0.1 Cl ₆ . The electrolyte obtained was found to have an ionic conductivity of 1.049mS/cm at room temperature.

Example 4

LiCl, zrCl ₄ 、DyCl ₃ 、NbCl ₅ Added to ZrO in a glove box in a molar ratio of 1.97:0.77:0.1:0.13 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _1.97 Zr _0.77 Dy _0.1 Nb _0.13 Cl ₆ . The electrolyte obtained by measurement had an ion conductivity of 0.987mS/cm at room temperature.

Example 5

LiCl, zrCl ₄ 、DyCl ₃ 、NbCl ₅ Added to ZrO in a glove box in a molar ratio of 2.07:0.83:0.12:0.05 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _2.07 Zr _0.83 Dy _0.12 Nb _0.05 Cl ₆ . The electrolyte obtained was found to have an ionic conductivity of 1.143mS/cm at room temperature.

Example 6

LiCl, zrCl ₄ 、DyCl ₃ 、BiCl ₃ 、InCl ₃ 、NbCl ₅ The mixture was introduced into ZrO in a glove box in a molar ratio of 2.1:0.5:0.1:0.1:0.1:0.2 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _2.1 Zr _0.5 Dy _0.1 Bi _0.1 In _0.1 Nb _0.2 Cl ₆ . The electrolyte obtained was found to have an ionic conductivity of 1.100mS/cm at room temperature.

Example 7

LiCl, zrCl4, inCl3, moCl ₅ Adding the mixture to ZrO in a glove box in a molar ratio of 2:0.8:0.1:0.1 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained ₂ Zr _0.8 In _0.1 Mo _0.1 Cl ₆ . The ion conductivity of the electrolyte at room temperature was measured to be 0.436mS/cm.

Example 8

LiCl, liF, zrCl4, dyCl3 and NbCl ₅ Added to ZrO in a glove box in a molar ratio of 1.87:0.2:0.83:0.12:0.05 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _2.07 Zr _0.83 Dy _0.12 Nb _0.05 Cl _5.8 F _0.2 . The ion conductivity of the electrolyte at room temperature was measured to be 1.151mS/cm.

Comparative example 1

LiCl, zrCl ₄ Adding into ZrO in a glove box in a molar ratio of 2:1 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained ₂ ZrCl ₆ . The electrolyte obtained was found to have an ionic conductivity of 0.370mS/cm at room temperature.

Comparative example 2

LiCl, zrCl ₄ 、NbCl ₅ Adding the mixture to ZrO in a glove box in a molar ratio of 1.8:0.8:0.2 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _1.8 Zr _o.8 Nb _0.2 Cl ₆ . The ion conductivity of the electrolyte at room temperature was measured to be 0.413mS/cm.

Comparative example 3

LiCl, zrCl ₄ 、MoCl ₅ Added to Zr in a glove box in a molar ratio of 1.8:0.8:0.2O ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _1.8 Zr _0.8 Mo _0.2 Cl ₆ . The ion conductivity of the electrolyte at room temperature was measured to be 0.304mS/cm.

Comparative example 4

LiCl, zrCl ₄ 、DyCl ₃ Added to ZrO in a glove box in a molar ratio of 2.2:0.8:0.2 ₂ Adding ZrO with corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _2.2 Zr _0.8 Dy _0.2 Cl ₆ . The electrolyte obtained by measurement has room temperature ion conductivity of 0.980mS/cm.

Comparative example 5

LiCl, zrCl ₄ 、InCl ₃ Added to ZrO in a glove box in a molar ratio of 2.2:0.8:0.2 ₂ Adding ZrO in a corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _2.2 Zr _0.8 In _0.2 Cl ₆ . The electrolyte obtained was found to have an ionic conductivity of 0.428mS/cm at room temperature.

Comparative example 6

LiCl, zrCl ₄ 、LaCl ₃ Added to ZrO in a glove box in a molar ratio of 2.2:0.8:0.2 ₂ Adding ZrO in a corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _2.2 Zr _0.8 La _0.2 Cl ₆ . The ion conductivity of the electrolyte at room temperature was measured to be 0.405mS/cm.

Comparative example 7

LiCl, zrCl ₄ 、DyCl ₃ 、BaCl ₂ 、CfCl ₂ 、NbCl ₅ In the glove with the mol ratio of 2.3:0.5:0.1:0.1:0.1:0.2Adding into ZrO in a box ₂ Adding ZrO in a corresponding proportion into a ball milling tank ₂ Ball milling and sealing. Then, the ball milling tank is put into a high-energy ball mill, ball milling is carried out for 45 hours at the rotating speed of 530rpm, and Li is obtained _2.3 Zr _0.5 Dy _0.1 Ba _0.1 Cd0. ₁ Nb _0.2 Cl ₆ . The ion conductivity of the electrolyte at room temperature was measured to be 0.359mS/cm.

The testing method comprises the following steps:

1. conductivity-related test:

the specific test method comprises the following steps:

in a glove box, 80-120mg of the sample was weighed, and then the sample was poured into a solid-state battery mold having an inner diameter of 1cm and the mold was assembled. The mold was transferred out of the glove box, and a pressure of 3T was applied thereto for 1 minute. And then connecting the die to an electrochemical workstation for impedance testing to obtain the body impedance value of the sample. Taking out the sample in the die for tabletting, and testing the thickness of the tabletting. Calculating the final conductivity according to the formula σ=l/(ARb), wherein σ is the conductivity in S/cm,1 is the thickness of the tablet in cm; a is the area of the tablet, and the unit is cm2; rb is the bulk impedance of the sample in Ω).

All impedance spectra were tested at room temperature 25 ℃.

Sequence number	Halide chemical formula	Room temperature ionic conductivity mS/cm
			Example 1	Li ₂ Zr _0.8 In _0.1 Nb _0.1 Cl ₆	0.566
Example 2	Li ₂ Zr _0.8 La _0.1 Nb _0.1 Cl ₆	0.524
			Example 3	Li ₂ Zr _0.8 Dy _0.1 Nb _0.1 Cl ₆	1.049
Example 4	Li _1.97 Zr _0.77 Dy _0.1 Nb _0.13 Cl ₆	0.987
			Example 5	Li _2.07 Zr _0.83 Dy _0.12 Nb _0.05 Cl ₆	1.143
Example 6	Li _2.1 Zr _0.5 Dy _0.1 Bi _0.1 In _0.1 Nb _0.2 Cl ₆	1.100
			Example 7	Li ₂ Zr _0.8 In _0.1 Mo _0.1 Cl ₆	0.436
Example 8	Li _2.07 Zr _0.83 Dy _0.12 Nb _0.05 Cl _5.8 F _0.2	1.151
			Comparative example 1	Li ₂ ZrCl ₆	0.370
Comparative example 2	Li _1.8 Zr _0.8 Nb _0.2 Cl ₆	0.413
			Comparative example 3	Li _1.8 Zr _0.8 Mo _0.2 Cl ₆	0.304
Comparative example 4	Li _2.2 Zr _0.8 Dy _0.2 Cl ₆	0.980
			Comparative example 5	Li _2.2 Zr _0.8 In _0.2 Cl ₆	0.428
Comparative example 6	Li _2.2 Zr _0.8 La _0.2 Cl ₆	0.405
			Comparative example 7	Li _2.3 Zr _0.5 Dy _0.1 Ba _0.1 Cd _0.1 Nb _0.2 Cl ₆	0.359

As can be seen from examples and comparative examples of the present application, the 5-valent element is capable of doping Li with the 3-valent element ₂ ZrCl ₆ The overall properties of (2) are advantageously improved due to the special outer electronic structure of the pentavalent niobium. While the ion inversion rate of the halide solid electrolyte material can be improved to a certain extent by doping 3-valent elements or 5-valent elements independently, the improvement effect is smaller than that of the composite doping of niobium and 3-valent elements.

Meanwhile, nb has the best effect compared to other 5-valent elements, which can be exhibited only when it is matched with 3-valent elements, and when 2-, 3-, and 5-valent composite doping is formed with the relevant 2-valent element, the ion conductivity is rather lowered.

The foregoing description of the preferred embodiments of the present application is not intended to limit the invention to the particular embodiments of the present application, but to limit the scope of the invention to the particular embodiments of the present application.

Claims

1. A solid electrolyte material comprising a halide solid electrolyte having the chemical formula: li (Li) _2+a-b Zr _1-a-b A _a B _b X ₆ ；

Wherein the valence state of the element A is 3;

the valence state of the element B is 5;

element X is at least one of F, cl, br, I;

2+a-b has a value in the range of 1.85-2.45, preferably 2.0-2.3;

2. The solid electrolyte material of claim 1 wherein the element a is Ga ³⁺ 、In ³⁺ 、Al ³⁺ 、Fe ³ ⁺ 、Y ³⁺ 、Bi ³⁺ At least one of +3 valent lanthanide metals.

3. The solid state electrolyte material of claim 1 wherein the element a has an average ionic radius value of preferably 90-95pm.

4. A solid state electrolyte material as claimed in any one of claims 1 to 3 wherein the element B is niobium.

5. A solid state electrolyte material as claimed in any one of claims 1 to 3 wherein the concentration of element B in the halide solid state electrolyte is less than the concentration of element a.

6. A solid state electrolyte material according to any one of claims 1 to 3, wherein element X is a mixture, wherein element X comprises C1 and the molar ratio of C1 element in element X is in the range of 80-99.99%, preferably wherein the molar ratio of Cl element in element X is in the range of 83-96%.

7. A method of preparing the halide solid electrolyte according to any one of claims 1 to 6, wherein the method comprises:

and sintering a plurality of intermediates to obtain the halide solid electrolyte.

8. An electrode comprising the solid electrolyte material according to any one of claims 1 to 6.