Solid electrolyte material, preparation method, and electrode

Abstract

The present application provides a solid electrolyte material, a preparation method, an electrode, and a lithium-ion battery. The solid electrolyte material includes a halide solid electrolyte. The chemical formula of the halide solid electrolyte is: Li 2+a‑b Zr 1‑a‑b A a BbX6, wherein element A is at least one of trivalent metal elements, element B is at least one of tantalum or niobium with a valence of five, element X is at least one of F, Cl, Br, and 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, and the value range of a / b is 0.5-3.5. Relative to the standard structure of Li2ZrCl6, by doping with suitable types of A and B elements, the microstructure of the prepared halide solid electrolyte is regulated, the migration barrier of lithium ions therein is reduced, thereby increasing the ionic conductivity of the halide solid electrolyte.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a solid electrolyte material, a preparation method, and an electrode. Background Art

[0002] With the gradual depletion of fossil energy and the increasing prominence of environmental protection issues, new energy sources, represented by lithium-ion batteries, are considered a key means of solving current energy problems. However, traditional liquid lithium-ion batteries, due to their use of flammable, explosive, and toxic electrolytes, lack safety standards that meet increasingly stringent usage requirements, and their energy density is approaching process limits. Solid-state batteries, which use solid-state electrolytes in place of the separators and electrolytes found in traditional lithium-ion batteries, are currently recognized as a next-generation battery technology, and solid-state electrolyte materials are the core technology of solid-state batteries.

[0003] Current solid-state electrolyte materials primarily include polymer solid electrolytes, sulfide solid electrolytes, and oxide solid electrolytes. Each of these materials has its own advantages and disadvantages. For example, while sulfide solid electrolytes offer high ionic conductivity, they are overly sensitive to moisture and air, are costly to prepare, and are difficult to commercialize. While oxide solid electrolytes offer simple preparation processes and ease of commercialization, they exhibit poor interfacial properties with the positive and negative electrodes, impacting the overall performance of the battery.

[0004] Compared with oxide solid electrolytes and sulfide solid electrolytes, halide solid electrolytes are an emerging type of ceramic material, which has attracted attention due to its outstanding comprehensive advantages in terms of electrical conductivity, pressure resistance, mechanical adaptability, environmental stability, cost, etc. For ceramic materials, doping is currently considered an important method to improve material performance. Doping methods are divided into isovalent doping and heterovalent doping. Isovalent doping is generally used to adjust the binding energy between ions; while heterovalent doping can introduce some defects in the material structure, or change the carrier (such as lithium ion) concentration or change the microstructure, which is mainly reflected in some barrier values. However, the above doping theory is only a theoretical speculation, and it often produces many unpredictable effects for different material systems. Li2ZrCl6 has attracted the attention of halide solid electrolyte researchers due to its lower cost and comprehensive performance. For Li2ZrCl6, patent document CN112204675B discloses a halide solid electrolyte with a chemical formula of Li 6-4a M aX6, where M is selected from Group IVB elements such as Zr, Hf, and Ti. The data in the Examples section also recognize the different properties exhibited by elements such as Zr and Hf under different doping and ratios. The applicant's previous research has confirmed that Li2ZrCl6 doped with specific 3+ lanthanide elements such as Eu and Gd exhibits a different structure and higher ionic conductivity than doped with other elements. This doping effect exhibits personalized characteristics. Therefore, it is very necessary to develop a highly targeted doping method for Li2ZrCl6 materials. Summary of the Invention

[0005] In order to solve one or more of the above-mentioned technical problems existing in the prior art, the embodiments of the present application provide a solid electrolyte material, a preparation method, and an electrode to resolve the contradictory relationship between the performance and cost of current halide solid electrolytes, and to prepare a solid electrolyte material with lower cost and higher ionic conductivity.

[0006] In order to achieve the above objectives, the technical solutions adopted by this application to solve the technical problems are:

[0007] In a first aspect, the present application provides a solid electrolyte material, wherein the solid electrolyte material comprises a halide solid electrolyte, and the chemical formula of the halide solid electrolyte is: Li 2+a-b Zr 1-a-b A a B b X6;

[0008] Among them, the valence state of element A is 3;

[0009] The valence state of element B is 5;

[0010] Element X is at least one of F, Cl, Br, and I;

[0011] The value range of 2+ab is 1.85-2.45, preferably 2.0-2.3;

[0012] 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.

[0013] Preferably, element A is Ga3 + 、In 3+ 、Al 3+ 、Fe 3+ 、Y 3+ 、Bi 3+ , at least one of the +3 valent lanthanide metals.

[0014] Further preferably, the average ionic radius of the element A is preferably 90-95 pm.

[0015] It is understood that when element A is a mixture of multiple elements, for example: A1 al A2 a2 ......An an , whose average ionic radius is

[0016] Preferably, element B is niobium.

[0017] In a specific embodiment, the concentration of the element B in the halide solid electrolyte is less than the concentration of the element A.

[0018] 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 is in the range of 80-99.99%. Preferably, the molar ratio of the Cl element in the element X is in the range of 83-96%.

[0019] In a specific embodiment, the halide solid electrolyte is in any form of a glass phase, a glass-ceramic phase or a crystalline phase.

[0020] In a specific embodiment, the solid electrolyte material only includes the halide solid electrolyte, or is mainly composed of the halide solid electrolyte.

[0021] 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:

[0022] The lithium salt, the zirconium salt, the salt corresponding to the element A, and the salt corresponding to the element B are mixed in a mixing device at a preset stoichiometric ratio to obtain an intermediate;

[0023] The intermediate is sintered to obtain the halide solid electrolyte.

[0024] Preferably, the mixing device is a ball mill;

[0025] Further preferably, the mixing equipment is a ZrO2 ball mill.

[0026] Preferably, the ball milling speed of the ball mill is 200-800 rpm, and the ball milling time is 10-50 h.

[0027] Preferably, the sintering temperature is 150-350°C.

[0028] Preferably, the sintering time is 0-40 hours.

[0029] In a third aspect, corresponding to the above-mentioned solid electrolyte material, the present application also provides an electrode, which includes the above-mentioned solid electrolyte material.

[0030] In a specific embodiment, the electrode includes an active material layer, the active material layer includes a solid electrolyte layer, and the solid electrolyte layer includes the solid electrolyte material.

[0031] In a specific embodiment, the solid electrolyte layer is composed of a composite solid electrolyte, and the composite solid electrolyte includes the halide solid electrolyte.

[0032] Preferably, the mass content of the halide solid electrolyte in the solid electrolyte layer is 1-99.99 wt %.

[0033] In a specific embodiment, the thickness of the solid electrolyte layer is 0.1-100 microns; preferably, the thickness of the solid electrolyte layer is 1-20 microns.

[0034] In a specific embodiment, the electrode includes a positive electrode, and the active material layer includes a positive electrode active material layer.

[0035] In a specific embodiment, the electrode includes a negative electrode, and the active material layer includes a negative electrode active material layer.

[0036] In a fourth aspect, corresponding to the above-mentioned solid electrolyte material, the present application also provides a lithium-ion battery, the battery comprising a positive electrode, a negative electrode and an electrolyte, and the electrolyte at least comprises the above-mentioned solid electrolyte material.

[0037] The beneficial effects of the technical solution provided by the embodiments of the present application are:

[0038] The solid electrolyte material, preparation method, electrode, and lithium-ion battery provided in the embodiments of the present application include a halide solid electrolyte. Compared with the standard structure of Li2ZrCl6, by doping appropriate types of trivalent and pentavalent elements, the lithium ion concentration can be precisely controlled and the microstructure can be modified. Surprisingly, the comprehensive performance of the halide solid electrolyte is improved; especially when the pentavalent element is niobium (Nb), due to Nb 5+ The d orbital electrons in the electronic structure are 0, referring to the lithium-rich Li 1.25 Nb 0.25 Mn 0.5 O2 (Electrochem. Commun. 60, 70) and Li 1.3 Nb 0.3+x M 0.4-xO2 (M = Mn, Fe, Co, Ni) (Proc. Natl. Acad. Sci. USA 112, 7650) and other materials. The metal ions of the d0 structure can stabilize cationic disorder. When combined with trivalent elements, better effects can be achieved. This is only a guess and not a limitation on the scope of protection. After the introduction of Nb with d0 structure, the local disorder of the Li2ZrCl6 structure is improved on the basis of trivalent doping. This property is similar to that of inorganic substances with Garnet and NASICON structures (Zeng et al., Science 378, 1320-1324 (2022)). The local disordered structure can reduce the lithium ion migration barrier and accelerate diffusion, thereby improving the lithium ion transport performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0040] Figure 1 This is an impedance diagram of the halide solid electrolyte provided in Example 3 of the present application; DETAILED DESCRIPTION

[0041] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0042] The solution provided by the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0043] As described in the background, halide solid electrolytes such as Li3InCl6 have high production costs due to the use of large amounts of rare earth elements. To address this issue, halide solid electrolytes based on zirconium have been proposed. However, pure halide solid electrolytes based on tetravalent zirconium offer limited performance improvements and fail to effectively address the technical issue of halide solid electrolytes failing to meet practical performance requirements.

[0044] In order to solve one or more of the above problems, the present application creatively proposes a new solid electrolyte material, which includes a halide solid electrolyte. The chemical formula of the halide solid electrolyte is: Li 2+a-bZr 1-a- b A a B b X6, wherein the valence state of element A is +3, the valence state of element B is +5, and element X is at least one of F, Cl, Br, and I.

[0045] For the standard structure of Li2ZrCl6, by doping suitable types of A and B elements, the stoichiometric ratio of lithium elements in the prepared halide solid electrolyte can be precisely controlled within a certain range. Combined with the adjustment of its microstructure, a small amount of lithium deficiency or increasing the lithium concentration within a certain range can make the electrolyte exhibit excellent ionic conductivity. However, if the lithium content is too high or too low, it may bring negative effects. Therefore, in the embodiment of the present application, it is further defined that the value range of 2+ab is 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.

[0046] It is understood that the element represented by A has a valence of +3 in the chemical formula, the element represented by B has a valence of +5 in the chemical formula, and the halogen element represented by X has a valence of -1 in the chemical formula. The lanthanum (La) series 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), and Lu (lutetium).

[0047] Preferably, the element A is Ga3 + 、In 3+ 、Al 3+ 、Fe 3+ 、Y 3+ 、Bi 3+ , one or more of +3 valent lanthanide metals.

[0048] More preferably, the average ionic radius of the element A is preferably 90-95 pm.

[0049] It is understandable that when A is a mixture of multiple elements, for example: A1 a1 A2 a2 ......An an , whose average ionic radius is

[0050] Preferably, element B is niobium.

[0051] Due to the special outermost electronic structure (d 0), the doping of pentavalent niobium increases the disorder of trivalent doped Li2ZrCl6, and the doping effect is improved, thereby improving the ionic conductivity of the halide solid electrolyte.

[0052] The doping method of the present application is particularly suitable for Li2ZrCl6 materials with Zr as the main element.

[0053] In some specific embodiments, the element X is one of F, Cl, Br, and I.

[0054] In other specific embodiments, the element X is a mixture of two or more of F, Cl, Br, and I.

[0055] In the embodiment of the present application, the zirconium-containing halide solid electrolyte is co-doped with a +3-valent element and a +5-valent niobium element, which can effectively improve the ionic conductivity of the halide electrolyte at room temperature and improve the overall performance of the electrolyte material.

[0056] Preferably, the halide solid electrolyte is in any form of a glass phase, a glass-ceramic phase or a crystalline phase.

[0057] Preferably, the solid electrolyte material consists only of a halide solid electrolyte or has a halide solid electrolyte as a main component.

[0058] In a second aspect, the present application also provides a method for preparing the above-mentioned halide solid electrolyte, the method comprising:

[0059] S1: mixing a lithium salt, a zirconium salt, a salt corresponding to element A, and a salt corresponding to element B in a mixing device at a preset stoichiometric ratio to obtain an intermediate product;

[0060] S2: sintering the intermediate product to obtain the halide solid electrolyte.

[0061] Preferably, the mixing equipment in step S1 is a ball mill;

[0062] Further preferably, the mixing equipment in step S1 is a ZrO2 ball mill.

[0063] Preferably, the ball milling speed of the ball mill is 200-800 rpm, and the ball milling time is 10-50 h.

[0064] Preferably, the sintering temperature is 150-350°C.

[0065] Preferably, the sintering time is 0-40h.

[0066] In a preferred embodiment, the lithium salt and zirconium salt referred to in step S1 are lithium and zirconium halides, so as to avoid 2+a-b Zr1-a-b A a B b The introduction of other impurities into X6 halide solid electrolytes affects the structure and performance of the final product.

[0067] Corresponding to the above-mentioned solid electrolyte material, the present application also provides an electrode, which includes the above-mentioned solid electrolyte material.

[0068] In some specific embodiments, the electrode includes an active material layer, the active material layer includes a solid electrolyte layer, and the solid electrolyte layer includes the solid electrolyte material.

[0069] Preferably, the solid electrolyte layer contains only the halide solid electrolyte, that is, the solid electrolyte material is only composed of the halide solid electrolyte.

[0070] Further preferably, the solid electrolyte layer comprises two or more halide solid electrolytes.

[0071] It can be understood that the above two or more halide solid electrolytes are all selected from the halide solid electrolytes described in the first aspect, that is, the solid electrolyte layer is only composed of the halide solid electrolyte material involved in this application.

[0072] In some specific embodiments, the solid electrolyte layer is composed of a composite solid electrolyte, and the composite solid electrolyte includes the halide solid electrolyte.

[0073] It is understood that a composite solid electrolyte refers to a solid electrolyte component composed of two or more solid electrolyte materials. The composite solid electrolyte in this application can be understood as a solid electrolyte material composed of the halide solid electrolyte of this application and other types of solid electrolytes. This application does not specifically limit the types of other types of solid electrolytes. On the basis of not violating the inventive concept of this application, any known type of solid electrolyte can be used in this 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, etc.

[0074] As an embodiment, the oxide solid electrolyte may include 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 6.5 La3Zr 1.75 Te 0.25 O 12 、Li7La3Zr2O 12 、Li 6.2Ga 0.3 La 2.9 Rb 0.05 Zr2O 12 、Li 6.85 La 2.9 Ca 0.1 Zr 1.75 Nb 0.25 O 12 、Li 6.25 Al 0.25 La3Zr2O 12 、Li 6.75 La3Zr 1.75 Nb 0.25 O 12 And combinations thereof. One or more LI SICON type oxides may be selected from the group consisting of: Li 14 Zn(GeO4)4、Li 3+x (P 1-x Si x )O4 (where 0≤x<1), Li 3+x Ge x V 1-x O4 (where 0 < x < 1) and combinations thereof. One or more NASICON-type oxides may be defined by LiMM'(PO4)3, where M and M' are independently selected from Al, Ge, Ti, Sn, Hf, Zr, and La. For example, in certain variations, one or more NASICON-type oxides may be selected from the group consisting of: Li 1+x Al x Ge 2-x (PO4)3(LAGP)(where 0≤x≤2), Li 1+x Al x Ti 2-x (PO4)3(LATP)(where 0≤x≤2), Li 1+x Y x Zr 2-x (PO4)3(LYZP)(where 0≤x≤2), Li 1.a Al 0.3 Ti 1.7 (PO4)3, LiTi2(PO4)3, LiGeTi(PO4)3, LiGe2(PO4)3, LiHr2(PO4)3 and combinations thereof. One or more perovskite ceramics may be selected from the group consisting of: Li 3.3 La 0.53 TiO3、LiSr 1.65 Zr 1.3 Ta 1.7 O9, Li 2x-y Sr 1-x Tay Zr 1-y O3 (where x=0.75y and 0.60<y<0.75), Li 3 / 8 Sr 7 / 16 Nb 3 / 4Zr 1 / 4 O3, (where 0 < x < 0.25) and combinations thereof. In one variation, one or more oxide-based materials may have a -5 S / cm to less than or equal to about 10 -1 S / cm ionic conductivity.

[0075] As an embodiment, the sulfide solid electrolyte may include one or more sulfide-based materials selected from the group consisting of: Li2S-P2S5, Li2S-P2S5-MS x (where M is Si, Ge, and Sn and 0≤x≤2), Li 3.4 Si 0.4 P0.6S4、Li 10 GeP2S 11.700.3 、Li 9.6 P3S 12 、Li7P3S 11 、Li9P3S9O3、Li 10.35 Si 1.35 P1. 65 S 12 、Li 9.81 Sn 0.81 P 2.19 S 12 、Li 10 (Si 0.5 Ge 0.5 )P2S 12 、Li(Ge 0.5 Sn 0.5 )P2S 12 、Li(Si 0.5 Sn 0.5 )PsS 12 、Li 1o GeP2S 12 (LGPS), Li6PS5X (wherein X is Cl, Br or I), Li7P2S8I, Li 10.35 Ge 1.a5 P 1.65 S 12 、Li 3.25 6e 0.25 P 0.75 S4, Li 1o SnP2S 12 、Li 10SiP2S 12 、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 、(1-x)P2S 5-x Li2S (where 0.5≤x≤0.7) and combinations thereof. In one variation, one or more sulfide-based materials may have a carbon content greater than or equal to about 10 -7 S / cm to an ionic conductivity of less than or equal to about 1 S / cm.

[0076] As an embodiment, the halide solid electrolyte may include one or more halide-based materials selected from the group consisting of Li2CdCl4, Li2MgCl4, Li2CdI4, Li2ZnI4, Li3OCl, LiI, Li5ZnI4, Li3OCl, 1-x Br x (where 0 < x < 1) and combinations thereof. In one variation, one or more halide-based materials may have a -8 S / cm to less than or equal to about 10 -1 S / cm ionic conductivity.

[0077] As an embodiment, the borate solid electrolyte may include one or more borate-based materials selected from the group consisting of Li2B4O7, Li2O-(B2O3)-(P2O5), and combinations thereof. In one embodiment, the one or more borate-based materials may have a carbon content greater than or equal to about 10 -7 S / cm to less than or equal to about 10 -2 S / cm ionic conductivity.

[0078] As an embodiment, the nitride solid electrolyte may include one or more nitride-based materials selected from the group consisting of Li3N, Li7PN4, LiSi2N3, and combinations thereof. In one embodiment, the one or more nitride-based materials may have a carbon content greater than or equal to about 10 -9 S / cm to an ionic conductivity of less than or equal to about 1 S / cm.

[0079] As an embodiment, the hydride solid electrolyte may include one or more hydride-based materials selected from the group consisting of Li3AlH6, LiBH4, LiBH4-LiX (wherein X is one of Cl, Br and I), LiNH2, Li2NH, LiBH4-LiNH2 and combinations thereof. In one embodiment, the one or more hydride-based materials may have a carbon content greater than or equal to about 10 -7S / cm to less than or equal to about 10 -2 S / cm ionic conductivity.

[0080] Preferably, the mass content of the halide solid electrolyte in the solid electrolyte layer is 1-99.99 wt %.

[0081] This application does not specifically limit the thickness of the solid electrolyte layer. The thickness of the solid electrolyte layer can be adjusted as necessary without violating the inventive concept of this application. It can be understood that routine adjustments to the thickness of the solid electrolyte layer fall within the scope of protection of this application.

[0082] As an illustrative example only, and not a limitation of the scope of protection, the thickness of the solid electrolyte layer is 0.1-100 microns; preferably, the thickness of the solid electrolyte layer is 1-20 microns.

[0083] In some specific embodiments, the electrode includes a positive electrode, and the active material layer includes a positive electrode active material layer.

[0084] In some specific embodiments, the electrode includes a negative electrode, and the active material layer includes a negative electrode active material layer.

[0085] It's known in the art to incorporate a solid electrolyte layer on the surface of the positive electrode active material layer to improve battery safety. Unlike the solid electrolyte membrane that acts as an electronic insulator between the positive and negative electrodes, this solid electrolyte layer primarily prevents side reactions in the positive electrode material. Furthermore, it also increases the internal resistance of the battery to a certain extent.

[0086] 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 embodiments of the present application do not particularly limit the positive electrode active material and the negative electrode active material. On the basis of not violating the inventive concept of the present application, any known types of positive electrode active materials and negative electrode active materials can be used in the present application. It is only used as an illustrative example, not any limitation on the scope of protection. The negative electrode active material may include a lithium-based negative electrode active material, which includes, for example, lithium metal and / or lithium alloy. In other embodiments, the negative electrode may be a silicon-based negative electrode active material, which includes 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 negative electrode active material may include a carbonaceous-based negative electrode active material, which includes one or more of graphite, graphene, carbon nanotubes (CNTs) and combinations thereof. In yet another embodiment, the negative electrode active material includes one or more negative electrode active materials that accept lithium, such as lithium titanium oxide (Li4Ti5O 12), one or more transition metals (such as tin (Sn)), one or more metal oxides (such as vanadium oxide (V2O5), tin oxide (SnO), titanium dioxide (TiO2)), titanium niobium oxide (TixNbyOz, where 0≤x≤2, 0≤y≤24 and 0≤z≤64), metal alloys (such as copper-tin alloy (Cu6Sn5)) and one or more metal sulfides (such as iron sulfide (FeS)), etc.

[0087] The positive electrode active material can 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 electrode electroactive materials selected from the group consisting of LiCoO2 (LCO), LiNi x Mn y Co 1-x-y O2 (where 0≤x≤1 and 0≤y≤1), LiNi1 -x-y Co x Al y O2 (where 0≤x≤1 and 0≤y≤1), LiNi x Mn 1-x O2 (where 0≤x≤1), and Li 1+x MO2 (wherein M is one of Mn, Ni, Co and Al and 0≤x≤1). The spinel cathode comprises one or more lithium-based positive electroactive materials selected from the group consisting of LiMn2O4 (LMO) and LiNi x Mn 1.5 O4. The olivine-type cathode comprises one or more lithium-based positive electroactive materials LiMPO4 (wherein M is at least one of Fe, Ni, Co and Mn). The polyanion cation comprises, for example, a phosphate such as LiV2(PO4)3 and / or a silicate such as LiFeSiO4.

[0088] The positive electrode active material and the negative electrode active material are optionally mixed with a binder, and the binder includes but is not limited to polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (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. At the same time, the positive electrode active material layer and the negative electrode active material layer can optionally add 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 (such as KETCHEN™ black or DENKA™ black), carbon fibers and nanotubes, graphene, and the like. Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, polypyrrole, and the like.

[0089] Corresponding to the above-mentioned solid electrolyte material, the present application also provides a lithium-ion battery, which includes a positive electrode, a negative electrode and an electrolyte, and the electrolyte at least includes the above-mentioned solid electrolyte material.

[0090] It is understandable that the electrolyte can be composed only of the above-mentioned solid electrolyte material, that is, the lithium-ion battery includes a positive electrode, a negative electrode, and a solid electrolyte material, and the solid electrolyte material is located between the positive electrode and the negative electrode to isolate the positive electrode and the negative electrode.

[0091] As a preferred embodiment, the electrolyte may further include other electrolyte materials.

[0092] It is understandable that any suitable electrolyte that can conduct lithium ions between the positive electrode and the negative electrode can be used in the lithium-ion battery, whether in the form of solid, liquid, solid-liquid mixture or gel. The present application does not particularly limit the electrolyte system of the lithium-ion battery. On the basis of not violating the inventive concept of the present application, the lithium-ion battery can apply any known electrolyte system. Based on the understanding of the prior art knowledge in this field, the solid-liquid mixed electrolyte system is a mixture of a non-aqueous electrolyte and a solid electrolyte, while the solid electrolyte system is composed only of a solid electrolyte. It should be understood that the solid electrolyte can be composed of a solid electrolyte material, or it can be composed of two or more materials, and the two or more solid electrolyte materials can be the same type of solid electrolyte material, or they can be different types of solid electrolyte materials.

[0093] In some specific embodiments, the electrolyte may be a non-aqueous electrolyte. When the electrolyte is a non-aqueous electrolyte, the lithium-ion battery further includes a separator, such as a membrane. The non-aqueous electrolyte comprises 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 in which a liquid or semi-solid electrolyte can be absorbed into the pores.

[0094] The organic solvent herein can use any organic solvent without particular limitation, as long as it can act 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 ε-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), ethyl methyl carbonate (MEC), ethyl methyl 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 an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolanes; or sulfolane.

[0095] As the lithium salt here, any lithium salt may be used without particular limitation as long as it can provide lithium ions used in the lithium secondary battery. Specifically, the points include but are not limited to lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF4), lithium difluorooxalatoborate (LiBF2(C2O4))(LiODFB), lithium tetraphenylborate (LiB(C6H5)4), lithium bis(oxalato)borate (LiB(C2O4)2)(LiBOB), lithium tetrafluorooxalatophosphate (LiPF4(C2O4))(LiFOP), lithium nitrate (LiNO3), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonyl imide) (LITFSI)(LiN(CF3SO2)2), lithium bis(fluorosulfonyl imide) (LiN(FSO2)2)(LIFSI) and combinations thereof. In certain variations, a lithium salt selected from lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl imide) (LiTFSI)(LiN(CF3SO2)2), lithium bis(fluorosulfonyl imide) (LiN(FSO2)2)(LiFSI), lithium fluoroalkyl phosphonate (LiFAP), lithium phosphate (Li3PO4), and combinations thereof can be used as the lithium salt. The lithium salt can be used in a concentration range of 0.1-2.0 M, such as 0.1 M, 0.3 M, 0.5 M, 0.7 M, 0.8 M, 1 M, 1.2 M, 1.3 M, 1.5 M, 1.6 M, 1.8 M, or 2.0 M. 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 efficiently transferred.

[0096] Solid electrolyte materials can be used as both ion conductors to transport and conduct lithium ions and electrical insulators to prevent charge or current from flowing from the negative electrode to the positive electrode. Therefore, a membrane composed of a solid electrolyte material can replace a separator. This application does not specifically limit the relevant solid electrolyte materials, except for the halide solid electrolytes involved in this application. Without violating the inventive concept of this application, any known solid electrolyte material can be used in this application, including but not limited to oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, polymer solid electrolytes, nitride solid electrolytes, boride solid electrolytes, etc. These will not be detailed here one by one, and the relevant content can be referred to as described above.

[0097] The present disclosure is described in more detail with reference to the following examples.

[0098] Example 1

[0099] LiCl, ZrCl4, InCl3, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2:0.8:0.1:0.1, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 h to obtain Li2Zr 0.8 In 0.1 Nb 0.1 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.566 mS / cm.

[0100] Example 2

[0101] LiCl, ZrCl4, LaCl3, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2:0.8:0.1:0.1, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li2Zr 0.8 La 0.1 Nb 0.1 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.524 mS / cm.

[0102] Example 3

[0103] LiCl, ZrCl4, DyCl3, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2:0.8:0.1:0.1, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li2Zr 0.8 Dy 0.1 Nb 0.1 The room temperature ionic conductivity of the obtained electrolyte was measured to be 1.049 mS / cm.

[0104] Example 4

[0105] LiCl, ZrCl4, DyCl3, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 1.97:0.77:0.1:0.13, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li 1.97 Zr 0.77 Dy 0.1 Nb 0.13 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.987 mS / cm.

[0106] Example 5

[0107] LiCl, ZrCl4, DyCl3, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2.07:0.83:0.12:0.05, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li 2.07 Zr 0.83 Dy 0.12 Nb 0.05 The room temperature ionic conductivity of the obtained electrolyte was measured to be 1.143 mS / cm.

[0108] Example 6

[0109] LiCl, ZrCl4, DyCl3, BiCl3, InCl3, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2.1:0.5:0.1:0.1:0.1:0.2, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li 2.1 Zr 0.5 Dy 0.1 Bi 0.1 In 0.1 Nb 0.2 The room temperature ionic conductivity of the obtained electrolyte was measured to be 1.100 mS / cm.

[0110] Example 7

[0111] LiCl, ZrCl4, InCl3, and MoCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2:0.8:0.1:0.1, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 h to obtain Li2Zr 0.8 In 0.1 Mo 0.1 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.436 mS / cm.

[0112] Example 8

[0113] LiCl, LiF, ZrCl4, DyCl3, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 1.87:0.2:0.83:0.12:0.05, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li 2.07 Zr0.83 Dy 0.12 Nb 0.05 Cl 5.8 F 0.2 The room temperature ionic conductivity of the electrolyte was measured to be 1.151 mS / cm.

[0114] Comparative Example 1

[0115] LiCl and ZrCl₄ were added to a ZrO₂ ball mill in a glove box at a molar ratio of 2:1. The corresponding proportion of ZrO₂ ball milling beads was added and the jar was sealed. The mill was then placed in a high-energy ball mill and milled at 530 rpm for 45 hours to produce Li₂ZrCl₆. The resulting electrolyte exhibited a room-temperature ionic conductivity of 0.370 mS / cm.

[0116] Comparative Example 2

[0117] LiCl, ZrCl4, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 1.8:0.8:0.2, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li 1.8 Zr o.8 Nb 0.2 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.413 mS / cm.

[0118] Comparative Example 3

[0119] LiCl, ZrCl4, and MoCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 1.8:0.8:0.2, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li 1.8 Zr 0.8 Mo 0.2 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.304 mS / cm.

[0120] Comparative Example 4

[0121] LiCl, ZrCl4, and DyCl3 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2.2:0.8:0.2, and ZrO2 ball milling beads of the corresponding proportion were added and sealed. Then, the ball mill was placed in a high-energy ball mill and milled at a speed of 530 rpm for 45 hours to obtain Li 2.2 Zr 0.8 Dy 0.2Cl6. The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.980 mS / cm.

[0122] Comparative Example 5

[0123] LiCl, ZrCl4, and InCl3 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2.2:0.8:0.2. ZrO2 ball milling beads were added to the ball mill and sealed. The ball mill was then placed in a high-energy ball mill and milled at 530 rpm for 45 h to obtain Li 2.2 Zr 0.8 In 0.2 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.428 mS / cm.

[0124] Comparative Example 6

[0125] LiCl, ZrCl4, and LaCl3 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2.2:0.8:0.2. ZrO2 ball milling beads were added to the ball mill and sealed. The ball mill was then placed in a high-energy ball mill and milled at 530 rpm for 45 h to obtain Li 2.2 Zr 0.8 La 0.2 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.405 mS / cm.

[0126] Comparative Example 7

[0127] LiCl, ZrCl4, DyCl3, BaCl2, CfCl2, and NbCl5 were added to a ZrO2 ball mill in a glove box at a molar ratio of 2.3:0.5:0.1:0.1:0.1:0.2. ZrO2 ball milling beads were added to the ball mill and sealed. The ball mill was then placed in a high-energy ball mill and milled at 530 rpm for 45 h to obtain Li 2.3 Zr 0.5 Dy 0.1 Ba 0.1 Cd0.1Nb 0.2 The room temperature ionic conductivity of the obtained electrolyte was measured to be 0.359 mS / cm.

[0128] Test method:

[0129] 1. Conductivity related tests:

[0130] Specific test method:

[0131] In the glove box, weigh 80-120 mg of the sample, then pour the sample into a solid-state battery mold with an inner diameter of 1 cm and assemble the mold. Take the mold out of the glove box, apply 3T of pressure to it, and hold it for 1 minute. Then connect the mold to the electrochemical workstation and perform an impedance test to obtain the bulk impedance value of the sample. Take out the sample tablet in the mold and test the thickness of the tablet. Calculate the final conductivity according to the formula σ=l / (ARb), where σ is the conductivity in S / cm, 1 is the thickness of the tablet in cm; A is the area of ​​the tablet in cm2; Rb is the bulk impedance of the sample in Ω).

[0132] All impedance spectra were measured at room temperature (25°C).

[0133] Serial number Halide chemical formula Room temperature ionic conductivity mS / cm Example 1 <![CDATA[Li2Zr 0.8 In 0.1 Nb 0.1 Cl6]]> 0.566 Example 2 <![CDATA[Li2Zr 0.8 There 0.1 Number 0.1 Cl6]]> 0.524 Example 3 <![CDATA[Li2Zr 0.8 Dy 0.1 Nb 0.1 Cl6]]> 1.049 Example 4 <![CDATA[Li 1.97 Zr 0.77 Dy 0.1 Nb 0.13 Cl6]]> 0.987 Example 5 <![CDATA[Li 2.07 Zr 0.83 Dy 0.12 Nb 0.05 Cl6]]> 1.143 Example 6 <![CDATA[Li 2.1 Zr 0.5 Dy 0.1 Bi 0.1 In 0.1 Nb 0.2 Cl6]]> 1.100 Example 7 <![CDATA[Li2Zr 0.8 In 0.1 Mon 0.1 Cl6]]> 0.436 Example 8 <![CDATA[Li 2.07 Zr 0.83 Dy 0.12 Nb 0.05 Cl 5.8 F 0.2 ]]> 1.151 Comparative Example 1 <![CDATA[Li2ZrCl6]]> 0.370 Comparative Example 2 <![CDATA[Li 1.8 Zr 0.8 Nb 0.2 Cl6]]> 0.413 Comparative Example 3 <![CDATA[Li 1.8 Zr 0.8 Mon 0.2 Cl6]]> 0.304 Comparative Example 4 <![CDATA[Li 2.2 Zr 0.8 House 0.2 Cl6]]> 0.980 Comparative Example 5 <![CDATA[Li 2.2 Zr 0.8 In 0.2 Cl6]]> 0.428 Comparative Example 6 <![CDATA[Li 2.2 Zr 0.8 La 0.2 Cl6]]> 0.405 Comparative Example 7 <![CDATA[Li 2.3 Zr 0.5 Dy 0.1 Ba 0.1 Cd 0.1 Nb 0.2 Cl6]]> 0.359

[0134] The examples and comparative examples of this application demonstrate that pentavalent elements can beneficially improve the overall performance of trivalent-doped Li2ZrCl6 due to the unique outer electron structure of pentavalent niobium. While doping with either a trivalent or pentavalent element alone can also improve the ion inversion rate of halide solid electrolyte materials to a certain extent, the improvement is less pronounced than combined doping with niobium and a trivalent element.

[0135] At the same time, compared with other pentavalent elements, Nb has the best effect, and this effect can only be reflected when it is matched with trivalent elements. When it forms a divalent, trivalent, and pentavalent composite doping with related divalent elements, the ionic conductivity will decrease instead.

[0136] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A solid electrolyte material, characterized in that The solid electrolyte material includes a halide solid electrolyte, and the chemical formula of the halide solid electrolyte is: Li 2+a-b Zr 1-a-b A a B b X6; Among them, the valence state of element A is 3; The valence state of element B is 5; Element X is at least one of F, Cl, Br, and I; The value range of 2+ab is 1.85-2.45; The value range of a+b is 0.1-0.5, and the value range of a / b is 0.5-3.5; The element A is Ga 3+ 、In 3+ 、Al 3+ 、Fe 3+ 、Y 3+ 、Bi 3+ , at least one of +3 valent lanthanide metals; The element B is niobium.

2. The solid electrolyte material according to claim 1, characterized in that The average ionic radius of the element A is 90-95 pm.

3. The solid electrolyte material according to claim 1, characterized in that The value range of 2+ab is 2.0-2.

3.

4. The solid electrolyte material according to claim 1, characterized in that The value range of a / b is 1-3.

5. The solid electrolyte material according to any one of claims 1 to 4, characterized in that The concentration of the element B in the halide solid electrolyte is less than the concentration of the element A.

6. The solid electrolyte material according to any one of claims 1 to 4, characterized in that The element X is a mixture, the element X contains Cl, and the molar ratio of Cl in the element X is in the range of 80-99.99%.

7. The solid electrolyte material according to claim 6, characterized in that The molar ratio of the Cl element in the element X ranges from 83% to 96%.

8. A method for preparing a halide solid electrolyte according to any one of claims 1 to 7, characterized in that: The method comprises: The lithium salt, the zirconium salt, the salt corresponding to the element A, and the salt corresponding to the element B are mixed in a mixing device at a preset stoichiometric ratio to obtain an intermediate; The intermediate is sintered to obtain the halide solid electrolyte.

9. An electrode, characterized in that The electrode comprises the solid electrolyte material according to any one of claims 1 to 7.

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