A low-carrier oxohalide solid electrolyte material and a preparation method thereof

Abstract

The present invention provides a low-carrier oxohalide solid electrolyte material and a preparation method thereof; the low-carrier oxohalide solid electrolyte material provided by the present invention has a general formula: A a M b OB c ; wherein, 0.3 < a < 0.7, 0.35 < b < 1.1, 1 < c < 4; the raw materials of the material include a transition metal oxide M z1 O z2 as a host structure, an alkali metal halide A x1 B x2 as a filler, and a transition metal halide M y1 B y2 ; the material A a M b OB c and the host structure M z1 O z2 have the same crystal structure; the consistency of the crystal structure helps to efficiently transport with fewer carriers, achieving the purpose of improving the ionic conductivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state batteries, and particularly relates to a low-carrier oxygen halide solid electrolyte material and a preparation method thereof. Background Art

[0002] Traditional liquid ion batteries have relatively high safety hazards due to the use of flammable organic liquid electrolytes, and the energy density of traditional liquid ion batteries has approached its theoretical value, making it difficult to further improve; therefore, there is an urgent need to develop a new energy storage system with high safety and high energy density.

[0003] Developing inorganic solid electrolytes and matching them with high-energy-density metal anodes can achieve high energy density and solve the flammability problem of traditional liquid batteries. The current research on inorganic solid electrolytes mainly focuses on materials such as oxides, sulfides, and halides; among them, halide solid electrolytes are a type of superionic conductor composed of halogen elements as anionic structural frameworks and metal elements acting as central metal cations; halide solid electrolytes have higher ionic conductivity and excellent deformability compared to oxides; compared with sulfide solid electrolytes, they have excellent oxidation stability and good water / air stability, so they are considered to have good commercial prospects.

[0004] However, despite the above advantages of inorganic solid electrolytes, they still face some challenges in practical applications. Whether it is inorganic solid electrolytes such as oxides, sulfides, or halides, a large amount of carriers such as lithium and sodium are required to maintain the crystal structure and high ionic conductivity; this not only increases the cost of the materials but also poses challenges to the sustainable use of resources. In addition, the ionic conductivity of inorganic solid electrolytes is usually lower than that of liquid electrolytes, which limits their charge and discharge rates and the rate performance of the batteries. At the same time, the interfacial stability between inorganic solid electrolytes and electrode materials is a challenge. Poor physical and mechanical stability may lead to structural stress at the electrode / electrolyte interface, affecting the electrochemical performance of the batteries. Therefore, how to research and optimize an inorganic solid electrolyte material that can improve battery performance while reducing the dependence on expensive metal resources such as lithium and improving the safety and economy of the batteries is of great significance for promoting the development and commercialization of solid-state battery technology. Summary of the Invention

[0005] In view of the problems in the prior art, the present invention discloses a low-carrier oxygen halide solid electrolyte material and a preparation method thereof. In the low-carrier oxygen halide solid electrolyte material provided by the present invention, the raw materials include transition metal oxide M z1 O z2 as the host structure, and alkali metal halide A x1 B x2and transition metal halide M y1 B y2 ; the material A a M b OB c and the host structure M z1 O z2 have the same crystal structure; the consistency of the crystal structure helps to efficiently transport with fewer carriers, achieving the purpose of improving ionic conductivity.

[0006] The present invention is achieved through the following technical solutions:

[0007] In the first aspect, the present invention provides a low-carrier oxohalide solid electrolyte material; the material has the general formula: A a M b OB c ; 0.3 < a < 0.7, 0.35 < b < 1.1, 1 < c < 4;

[0008] The raw materials of the material include transition metal oxide M z1 O z2 as the host structure, alkali metal halide A x1 B x2 and transition metal halide M y1 B y2 ; the material A a M b OB c and the host structure M z1 O z2 have the same crystal structure;

[0009] Among them, the alkali metal A includes one or more of lithium (Li), sodium (Na), and potassium (K); M includes transition metal elements with a valence of +4 or higher; the halogen atom B includes one or more of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I); the transition metal elements with a valence of +4 or higher include one or more of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), hafnium (Hf), zirconium (Zr), cobalt (Co), nickel (Ni), tantalum (Ta), tungsten (W), rhenium (Re), vanadium (V), niobium (Nb), and tin (Sn).

[0010] As a further solution, in A x1 B x2 , M z1 O z2 and M y1 B y2 , x1, x2, y1, y2, z1, and z2 are all greater than 0; x1 = x2.

[0011] As a further solution, the material A a M b OB c is preferably selected from 1.2 < b / a < 2;

[0012] Furthermore, the material A a M b OB c is preferably selected from 0.5 < a < 0.6, 0.75 < b < 0.88, 2 < c < 3.5, 1.45 < b / a < 1.65.

[0013] As a further solution, the transition metal oxide M z1 O z2 is preferably selected from oxides containing transition metal elements with a +5 valence.

[0014] As a further solution, the transition metal oxide M z1 O z2 is preferably selected from one or more of Ta2O5, Nb2O5; the alkali metal halide A used as a filler x1 B x2 is preferably selected from one or more of LiCl, LiF, NaCl, LiBr; the transition metal halide M used as a filler y1 B y2 is preferably selected from one or more of TaCl5, NbCl5, TaBr5, NbBr5.

[0015] As a further solution, the low-carrier oxohalide solid electrolyte material is selected from Li 0.53 Nb 0.4 Ta 0.4 OCl 2.53 、Li 0.53 Ta 0.8 OCl2Br 0.53 、Li 0.42 Ta 0.32 Zr 0.32 OCl 1.26 、Li 0.66 Ta 0.5 Zr 0.5 OCl 3.16 、Li 0.6 TaOCl 3.79 、Li 0.405 Ta 0.5 OCl 1.9 、Li 0.325 Ta 0.6 OCl 1.325 、Li 0.56 Ta 0.8 OCl 2.56 、Li0.4 Ta 0.7 OCl 1.9 、Li 0.53 Ta 0.8 OCl 1.32 、Li 0.53 Ta 0.8 OCl 2.53 、Li 0.53 Nb 0.8 OCl 2.53 、Li 0.53 Zr 0.8 OCl 2.53 、Li 0.66 Ta 0.5 Sn 0.5 OCl 3.16 、Na 0.53 Ta 0.8 OCl 2.53 、Na 0.53 Nb 0.8 OCl 2.53 、Na 0.53 Zr 0.8 OCl 2.53 、K 0.53 Ta 0.8 OCl 2.53 、K 0.53 Nb 0.8 OCl 2.53 、K 0.53 Zr 0.8 OCl 2.53 、Li 0.53 Ta 0.8 OClF 2.53 、Li 0.53 Nb 0.8 OClF 2.53 、Li 0.53 Zr 0.8 OClF 2.53 、Na 0.53 Ta 0.8 OClF 2.53 、Na 0.53 Nb 0.8 OClF 2.53 、Na 0.53 Zr 0.8 OClF 2.53 、K 0.53 Ta 0.8 OF 2.53 、K 0.53 Nb 0.8 OF 2.53 、K 0.53 Zr 0.8 OF 2.53 、Li0.53 Ta 0.8 OBr 2.53 、Li 0.53 Nb 0.8 OBr 2.53 、Li 0.53 Zr 0.8 OBr 2.53 、Na 0.53 Ta 0.8 OBr 2.53 、Na 0.53 Nb 0.8 OBr 2.53 、Na 0.53 Zr 0.8 OBr 2.53 、K 0.53 Ta 0.8 OBr 2.53 、K 0.53 Nb 0.8 OBr 2.53 、K 0.53 Zr 0.8 OBr 2.53 one of

[0016] As a further option, the transition metal M is preferably one or more selected from niobium (Nb) and tantalum (Ta).

[0017] As a further option, the alkali metal A is preferably lithium (Li) ions.

[0018] As a further option, the halogen atom B is preferably one or more selected from Cl and Br.

[0019] As a further option, the material A a M b OB c is preferably selected from one or more of Li a Ta b OCl c 、Li a Nb b OCl c 、Li a Ta b OBr c 、Li a Nb b OBr c ; where 0.3 < a < 0.7, 0.35 < b < 1.1, 1 < c < 4, 1.2 < b / a < 2.

[0020] As a further option, the ionic conductivity of the material is greater than 1 mS cm -1 .

[0021] As a further embodiment, the mass percentage of A atoms in the material is selected from 1-3%, where the mass percentage refers to the proportion of the total mass of A atoms in the material A a M b OB c to the total mass.

[0022] Furthermore, the mass percentage of A atoms in the material is preferably selected from 1-1.5%.

[0023] In a second aspect, the present invention provides a method for preparing a low-carrier oxohalide solid electrolyte material; the preparation method includes:

[0024] Weigh A x1 B x2 , M y1 B y2 , M z1 O z2 under an inert gas according to the stoichiometric ratio of the required general formula, and mix them evenly to obtain a mixed material. Then, use the mechanical ball milling method to prepare the low-carrier oxohalide solid electrolyte material.

[0025] In the preparation method of the present invention, those skilled in the art can determine the corresponding stoichiometric ratio by feeding materials according to the stoichiometric ratio, that is, according to the proportional relationship between the elements of the low-carrier oxohalide solid electrolyte material, considering the losses during the feeding preparation process.

[0026] As a further embodiment, the inert gas in the preparation method includes one of argon or nitrogen.

[0027] As a further embodiment, the parameter conditions of the mechanical ball milling method in the preparation method are selected from: rotation speed: 300-600 rpm; diameter of the ball milling beads: 1-10 mm; mass of the ball milling beads: mass of the mixed material = (10-80):1; ball milling time is greater than 10 h.

[0028] In a third aspect, the present invention provides a battery, which includes the low-carrier oxohalide solid electrolyte, a positive electrode sheet, a negative electrode sheet, and a separator described in the first aspect.

[0029] The features and beneficial effects of the present invention are:

[0030] The present invention prepares an oxygen halide solid electrolyte material with low carriers by selecting oxides of transition metals with a valence of +4 or higher as the host structure and filling them with halides of transition metals with a valence of +4 or higher and halides of alkali metals; a stable crystal framework is constructed by oxides of transition metals with a valence of +4 or higher; subsequently, halides of transition metals with a valence of +4 or higher and halides of alkali metals with high compatibility with the crystal framework are filled synergistically; making the migration of alkali metal ions in the solid electrolyte easier, thereby contributing to improving the charge-discharge efficiency and cycle stability of the battery.

[0031] Meanwhile, the present invention also finely regulates the composition elements and ratios of the materials to ensure good interfacial compatibility between the materials, thereby reducing the diffusion barrier between the interfaces, enhancing the mobility, promoting the structural stability during crystal growth, and obtaining a low-carrier oxygen halide solid electrolyte material with the same crystal structure as the host cell; the consistency of the crystal structure helps to achieve efficient transmission with fewer carriers, achieving the purpose of improving the ionic conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is the XRD diffraction pattern of Embodiment 1 of the present invention;

[0034] Figure 2 It is the XRD diffraction pattern of Embodiment 6 of the present invention;

[0035] Figure 3 It is the electrochemical impedance test pattern of Embodiment 1 of the present invention;

[0036] Figure 4 It is the electrochemical impedance test pattern of Embodiment 6 of the present invention;

[0037] Figure 5 It is the XRD diffraction pattern of Comparative Example 1 of the present invention;

[0038] Figure 6 It is the electrochemical impedance test pattern of Comparative Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] To facilitate the understanding of the present invention, the following will provide a more comprehensive description of the present invention, giving embodiments of the present invention, but not limiting the scope of the present invention thereby.

[0040] The applicant has found that oxygen halide inorganic solid electrolytes generally have high ionic conductivity, and their electrochemical window stability and deformability are excellent. The synthesis method is simple, and it has high research and application value. In addition, the applicant has also found that a high carrier concentration in inorganic solid electrolyte materials may lead to interface stability problems, increase the internal resistance of the battery, and may trigger interface side reactions, thus affecting the cycle stability and electrochemical performance of the battery. Therefore, this study is seeking a solid electrolyte material that maintains high ionic conductivity while reducing the carrier concentration; and the following research has been carried out.

[0041] In a first aspect, the present invention provides a low-carrier oxygen halide solid electrolyte material; the material has a general formula: A a M b OB c ; 0.3 < a < 0.7, 0.35 < b < 1.1, 1 < c < 4;

[0042] The raw materials of the material include transition metal oxide M z1 O z2 as the host structure, alkali metal halide A x1 B x2 as the filler, and transition metal halide M y1 B y2 ; the material A a M b OB c and the host structure M z1 O z2 have the same crystal structure;

[0043] Among them, the alkali metal A includes one or more of lithium (Li), sodium (Na), and potassium (K); M includes transition metal elements with a valence of +4 or higher; the halogen atom B includes one or more of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I); the transition metal elements with a valence of +4 or higher include one or more of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), hafnium (Hf), zirconium (Zr), cobalt (Co), nickel (Ni), tantalum (Ta), tungsten (W), rhenium (Re), vanadium (V), niobium (Nb), and tin (Sn).

[0044] Compared with the prior art, the preparation of inorganic solid electrolytes requires a large amount of carriers to maintain the crystal structure and high ionic conductivity, which easily causes problems such as high interface impedance and poor interface stability. In this application, the host structure of oxide M z1 O z2 is selected to be constructed, and through M y1 B y2 halide, A that forms carriersx1 B x2 It is prepared by compounding as a filler; during the preparation process, by finely regulating the composition elements and ratios of the materials, good interfacial compatibility between the materials can be ensured, thereby reducing the diffusion barrier between the interfaces, enhancing the mobility, promoting the structural stability during the crystal growth process, and obtaining a low-carrier oxohalide solid electrolyte material with the same crystal structure as the host cell; usually, the consistency of the crystal structure is mostly manifested as the consistency of the XRD peaks during the testing process, and the consistent XRD peaks are beneficial for efficient transmission with fewer carriers, achieving the purpose of improving the ionic conductivity.

[0045] In the process of preparing the low-carrier oxohalide solid electrolyte of this application, oxides of transition metals with a valence of more than +4 are selected as the host structure, and halides of transition metals with a valence of more than +4 and halides of alkali metals are filled to prepare the low-carrier oxohalide solid electrolyte material; on the one hand, because oxides of transition metals with a valence of more than +4 tend to have a more stable electron arrangement, which helps to form various chemical bonds, making the interaction forces between the constructed structures stronger, providing a stable crystal framework, helping to maintain the structural integrity of the entire electrolyte material, and transition metal oxides with a high valence usually have larger ion channels and voids, which is beneficial for the filling of other substances, involving more electron transfer, thus storing and releasing more energy, making them have a higher energy density.

[0046] On the second hand, after constructing a stable crystal framework, we selected halides of transition metals with a valence of more than +4 that have high compatibility with the crystal framework. They have the same cations as the crystal framework, which can not only further maintain the stability of the host crystal structure, but also have good interfacial compatibility during the compounding process, which is beneficial for reducing side reactions at the interface, thereby enhancing the mobility, reducing the diffusion barrier, forming an efficient and through ionic transport channel, and optimizing the migration path and rate of the carriers; it is beneficial for maintaining a high ionic conductivity while reducing the required carrier content. On the third hand, we also used halides of alkali metals for co-filling; alkali metal ions have a low charge density and a small ionic radius, which makes their migration in the solid electrolyte easier, thus helping to improve the charge and discharge efficiency and cycle stability of the battery; and halides of alkali metals have relatively high thermal stability and chemical stability compared with other alkali metal compounds, and have good compatibility with the halide fillers of transition metals with a valence of more than +4, which helps to stably exist in the crystal structure, fully exert the ionic transport performance of the carriers; reduce the amount of carriers used and enhance the structural stability.

[0047] Filling the host structure with oxides of transition metals with a valence of +4 or higher, halides of transition metals with a valence of +4 or higher, and halides of alkali metals is beneficial to maintaining the consistency of the product crystal structure and the host crystal structure; mainly because the crystal structures have high compatibility, avoiding the formation of other crystalline phases or amorphous phases during the preparation process, which affects the ion transport rate and reduces the electrochemical application performance. The consistent crystal structure has a positive effect on both the thermal stability and physical and mechanical stability of the battery, helping to reduce the lattice mismatch and stress at the interface, thereby reducing the transport resistance of carriers at the interface, improving the ion migration efficiency, enhancing the interface stability, and thus achieving the purpose of high-speed transmission while reducing the amount of carriers used.

[0048] As a further solution, the A x1 B x2 , M z1 O z2 and M y1 B y2 wherein x1, x2, y1, y2, z1, z2 are all greater than 0; and x1 = x2.

[0049] As a further solution, the material A a M b OB c is preferably selected such that 1.2 < b / a < 2;

[0050] Furthermore, the material A a M b OB c is preferably selected such that 0.5 < a < 0.6, 0.75 < b < 0.88, 2 < c < 3.5, 1.45 < b / a < 1.65.

[0051] The element ratio of the material A a M b OB c within the preferred range ensures the formation of a stable structure in the solid electrolyte and simultaneously optimizes the ion migration path. By precisely controlling the values of a, b, and c, the conductivity and mechanical strength of the material can be further improved, thus meeting the requirements for battery performance in different application scenarios. In addition, the materials within this preferred range exhibit good chemical stability and thermal stability during the preparation process, helping to extend the service life of the battery.

[0052] As a further solution, the transition metal oxide M z1 O z2 is preferably selected from oxides containing transition metal elements with a valence of +5.

[0053] Elements within this range have stable valence states of chemical combination. The formed oxides have more stable mechanical properties and thermal stability within a relatively wide electrochemical window. When preparing solid electrolytes with other fillers, it is conducive to reducing the volume change during the lattice growth process and decreasing the generation of side reactions, thereby forming a consistent lattice structure; reducing the transport energy barrier of carriers and achieving the preparation of oxygen halide solid electrolyte fillers with low carriers and high conductivity.

[0054] As a further solution, the transition metal oxide M z1 O z2 is preferably selected from one or more of Ta2O5 and Nb2O5; the alkali metal halide A x1 B x2 used as a filler is preferably selected from one or more of LiCl, LiF, NaCl, and LiBr; the transition metal halide M y1 B y2 used as a filler is preferably selected from one or more of TaCl5, NbCl5, TaBr5, and NbBr5.

[0055] As a further solution, the low-carrier oxygen halide solid electrolyte material is selected from Li 0.53 Nb 0.4 Ta 0.4 OCl 2.53 、Li 0.53 Ta 0.8 OCl2Br 0.53 、Li 0.42 Ta 0.32 Zr 0.32 OCl 1.26 、Li 0.66 Ta 0.5 Zr 0.5 OCl 3.16 、Li 0.6 TaOCl 3.79 、Li 0.405 Ta 0.5 OCl 1.9 、Li 0.325 Ta 0.6 OCl 1.325 、Li 0.56 Ta 0.8 OCl 2.56 、Li 0.4 Ta 0.7 OCl 1.9 、Li 0.53 Ta 0.8 OCl 1.32 、Li 0.53 Ta 0.8 OCl 2.53 、Li0.53 Nb 0.8 OCl 2.53 、Li 0.53 Zr 0.8 OCl 2.53 、Li 0.66 Ta 0.5 Sn 0.5 OCl 3.16 、Na 0.53 Ta 0.8 OCl 2.53 、Na 0.53 Nb 0.8 OCl 2.53 、Na 0.53 Zr 0.8 OCl 2.53 、K 0.53 Ta 0.8 OCl 2.53 、K 0.53 Nb 0.8 OCl 2.53 、K 0.53 Zr 0.8 OCl 2.53 、Li 0.53 Ta 0.8 OClF 2.53 、Li 0.53 Nb 0.8 OClF 2.53 、Li 0.53 Zr 0.8 OClF 2.53 、Na 0.53 Ta 0.8 OClF 2.53 、Na 0.53 Nb 0.8 OClF 2.53 、Na 0.53 Zr 0.8 OClF 2.53 、K 0.53 Ta 0.8 OF 2.53 、K 0.53 Nb 0.8 OF 2.53 、K 0.53 Zr 0.8 OF 2.53 、Li 0.53 Ta 0.8 OBr 2.53 、Li 0.53 Nb 0.8 OBr 2.53 、Li 0.53 Zr 0.8 OBr 2.53 、Na0.53 Ta 0.8 OBr 2.53 、Na 0.53 Nb 0.8 OBr 2.53 、Na 0.53 Zr 0.8 OBr 2.53 、K 0.53 Ta 0.8 OBr 2.53 、K 0.53 Nb 0.8 OBr 2.53 、K 0.53 Zr 0.8 OBr 2.53 One of TaOBr, NaNbOBr, NaZrOBr, KTaOBr, KNbOBr, KZrOBr.

[0056] As a further solution, the transition metal M is preferably one or more selected from niobium (Nb) and tantalum (Ta).

[0057] As a further solution, the alkali metal A is preferably lithium (Li) ions. Among alkali metal ions, lithium ions have a smaller ionic radius and a lower migration barrier, which helps to exhibit a higher mobility in the solid electrolyte; at the same time, lithium ions also have better electrochemical stability. Therefore, lithium ions as carriers have a more excellent performance in improving the electrochemical performance of the battery.

[0058] As a further solution, the halogen atom B is preferably one or more selected from Cl and Br; the optimized halogen atoms can form a stable oxohalide structure with the transition metal M and the alkali metal A. Their ionic radii have a good matching effect with the radius of oxygen ions, which makes it easier for them to maintain the original arrangement in the crystal structure and avoid causing serious lattice distortion in the crystal structure, thus maintaining the consistency of the crystal structure; this consistency helps to maintain the stability of the electrolyte material, thereby forming a stable ion transport channel in the solid electrolyte. In addition, the electronegativity difference between Cl and Br can regulate the chemical stability of the solid electrolyte, so that the solid electrolyte can maintain good chemical and electrochemical stability during the charge and discharge process of the battery, thereby extending the service life of the battery.

[0059] As a further solution, the material A a M b OB c is preferably selected from LiTaOCl, LiNbOCl, LiTaOBr a Ta b OCl c 、Li a Nb b OCl c 、Li a Ta b OBr c, Li a Nb b OBr c One or more of them; wherein, 0.3 < a < 0.7, 0.35 < b < 1.1, 1 < c < 4, 1.2 < b / a < 2.

[0060] The materials within this range can achieve the best coordination between the crystal structure and the ion migration path; have a relatively fast ion migration path, so that a lower carrier can be used to achieve better ionic conductivity, improving the electrochemical performance and cycle stability of the battery.

[0061] As a further solution, the ionic conductivity of the material is greater than 1 mS cm -1 .

[0062] As a further solution, the mass percentage of A atoms in the material is selected from 1-3%, wherein the mass percentage refers to the proportion of the total mass of A atoms in the total mass of the material A a M b OB c total mass.

[0063] Furthermore, the mass percentage of A atoms in the material is preferably selected from 1-1.5%.

[0064] The mass percentage of A atoms in this application can ensure that within the range of maintaining a low carrier content, a higher ion migration ability is provided; avoiding the over-high carrier content, which may cause a crowding effect in the electrolyte and hinder the movement of ions; at the same time, avoiding the serious problems of increased resistance and dendritic growth that may be caused.

[0065] In the second aspect, the present invention provides a preparation method of a low-carrier oxygen halide solid electrolyte material; the preparation method includes:

[0066] Weigh A x1 B x2 , M y1 B y2 , M z1 O z2 in the stoichiometric ratio of the required general formula under an inert gas, and mix them evenly to obtain a mixed material, and prepare the low-carrier oxygen halide solid electrolyte material by mechanical ball milling of the mixed material.

[0067] In the preparation method of the present invention, those skilled in the art can determine the corresponding stoichiometric ratio according to the stoichiometric ratio of the feed, that is, according to the proportional relationship between the elements of the low-carrier oxygen halide solid electrolyte material, considering the loss during the feed preparation process.

[0068] As a further solution, the inert gas in the preparation method includes one of argon or nitrogen.

[0069] As a further solution, the parameter conditions of the mechanical ball milling method in the preparation method are selected from the rotation speed: 300 - 600 rpm; the diameter of the ball milling beads: 1 - 10 mm; the mass of the ball milling beads: the mass of the mixed material = (10 - 80):1; the ball milling time is greater than 10 h.

[0070] In a third aspect, the present invention provides a battery, which includes the low-carrier oxohalide solid electrolyte, a positive electrode sheet, a negative electrode sheet, and a separator described in the first aspect.

[0071] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0072] The chemical raw materials involved in the following examples and comparative examples are all prior art and are obtained through commercial purchase. The experimental devices, testing devices, etc. involved in the following examples and comparative examples are all conventional devices in the art, without special requirements and limitations.

[0073] Example 1

[0074] Li 0.53 Ta 0.8 OCl 2.53 Preparation: Under a nitrogen atmosphere, LiCl, Ta2O5, and TaCl5 are weighed according to the stoichiometric ratio of the general formula, and the above materials are mixed evenly; then the above mixed powder is subjected to high-energy ball milling at a rotation speed of 500 rpm (revolutions per minute) under a nitrogen atmosphere (the diameter of the ball milling beads is 5 mm, the mass of the ball milling beads: the mass of the mixed material = 30:1), for 20 h to obtain the low-carrier oxohalide solid electrolyte.

[0075] Example 2

[0076] The specific steps and preparation method are the same as those in Example 1, except that: for the preparation of Li 0.53 Nb 0.4 Ta 0.4 OCl 2.53 : Under an inert gas, LiCl, Ta2O5, and NbCl5 are weighed according to the stoichiometric ratio of the general formula, and the above materials are mixed evenly.

[0077] Example 3

[0078] The specific steps and preparation method are the same as those in Example 1, except that: for the preparation of Li 0.53 Ta 0.8 OCl2Br 0.53: Weigh LiBr, Ta2O5, and TaCl5 according to the stoichiometric ratio of the general formula under an inert gas, and mix the above materials evenly.

[0079] Example 4

[0080] The specific steps and preparation method are the same as those in Example 1, except that: prepare Li 0.53 Nb 0.4 Ta 0.4 OCl 2.53 : Weigh LiCl, Nb2O5, and TaCl5 according to the stoichiometric ratio of the general formula under an inert gas, and mix the above materials evenly.

[0081] Example 5

[0082] The specific steps and preparation method are the same as those in Example 1, except that: prepare Li 0.42 Ta 0.32 Zr 0.32 OCl 1.26 Weigh LiCl, ZrCl4, and Ta2O5 according to the stoichiometric ratio of the general formula under an inert gas, and mix the above materials evenly.

[0083] Example 6

[0084] The specific steps and preparation method are the same as those in Example 1, except that: prepare Na 0.53 Ta 0.8 OCl 2.53 ; Weigh NaCl, Ta2O5, and TaCl5 according to the stoichiometric ratio of the general formula under an inert gas, and mix the above materials evenly.

[0085] Example 7

[0086] The specific steps and preparation method are the same as those in Example 1, except that: prepare Li 0.66 Ta 0.5 Zr 0.5 OCl 3.16 ; Weigh LiCl, ZrO2, and TaCl5 according to the stoichiometric ratio of the general formula under an inert gas, and mix the above materials evenly.

[0087] Example 8

[0088] The specific steps and preparation method are the same as those in Example 1, except that: prepare Li 0.66 Ta 0.5 Sn 0.5 OCl 3.16 ;; Weigh LiCl, SnO2, and TaCl5 according to the stoichiometric ratio of the general formula under an inert gas, and mix the above materials evenly.

[0089] Example 9

[0090] The specific steps and preparation method are the same as those in Example 1, with the difference that: to prepare Li 0.6 TaOCl 3.79 ; under an inert gas, weigh LiCl, Ta2O5 and TaCl5 according to the stoichiometric ratio of the general formula, and mix the above materials evenly.

[0091] Comparative Example 1

[0092] The specific steps and preparation method are the same as those in Example 1, with the difference that: to prepare Li 0.88 Ta 0.66 Sb 0.66 OCl 4.21 ; under an inert gas, weigh LiCl, Sb2O3 and TaCl5 according to the stoichiometric ratio of the general formula, and mix the above materials evenly.

[0093] Comparative Example 2

[0094] The specific steps and preparation method are the same as those in Example 1, with the difference that: to prepare Li 2.17 Ta2OCl 10.16 ; under an inert gas, weigh LiCl, Ta2O5 and TaCl5 according to the stoichiometric ratio of the general formula, and mix the above materials evenly.

[0095] Comparative Example 3

[0096] Li 0.3 Ta 0.4 Cl 2.53 Preparation of: Under a nitrogen atmosphere, weigh LiCl and TaCl5 according to the stoichiometric ratio of the general formula, and mix the above materials evenly; then, under a nitrogen atmosphere, perform high-energy ball milling on the above mixed powder at a rotation speed of 500 rpm (revolutions per minute) (the diameter of the ball milling beads is 5 mm, and the mass of the ball milling beads: the mass of the mixed material = 30:1) for 20 h to obtain a solid electrolyte.

[0097] Comparative Example 4

[0098] Li 0.3 Ta 0.4 Cl 2.53 Preparation of: Under a nitrogen atmosphere, weigh LiCl and TaCl5 according to the stoichiometric ratio of the general formula, and mix the above materials evenly; then, under a nitrogen atmosphere, perform high-energy ball milling on the above mixed powder at a rotation speed of 500 rpm (revolutions per minute) (the diameter of the ball milling beads is 5 mm, and the mass of the ball milling beads: the mass of the mixed material = 30:1) for 40 h to obtain a solid electrolyte.

[0099] Specific test methods and conditions:

[0100] Put ~130 mg of electrolyte powder into a customized test battery mold with a diameter of 10 mm, where stainless steel serves as the blocking electrode, apply a pressure of 380 MPa, and perform tablet pressing. Use an SP-300 (Bio-logic) electrochemical workstation to test its electrochemical impedance information. Use electrochemical impedance spectroscopy to calculate its ionic conductivity according to the formula (σ = L / RA, where L is the thickness of the solid electrolyte, R is the resistance measured by electrochemical impedance spectroscopy, and A is the area).

[0101] Table 1

[0102]

[0103]

[0104] From the data in Table 1 and the examples and comparative examples, it can be seen that the oxyhalide solid electrolyte material prepared in Table 1, compared with the oxyhalide solid electrolyte material obtained in the comparative example, has a lower carrier content, higher ionic conductivity, and lower interfacial impedance, and shows better electrochemical performance in battery applications; in addition, through Figure 1 、 Figure 2 It can also be seen that the low-carrier oxyhalide solid electrolyte material prepared in the example has XRD diffraction peaks consistent with the host structure of its transition metal oxide; indicating that its lattice structure is consistent during the preparation process, thus obtaining a lower interfacial impedance and an efficient carrier transport path, so as to achieve the effect of improving the electrical performance with a lower carrier.

[0105] From Example 1 and Comparative Examples 1 and 2, it can be seen that when the prepared solid electrolyte material is not within the optimization range of this application, its ionic conductivity and impedance are not in a better range compared with the example, and its Figure 5 The X-ray diffraction peaks of the prepared solid electrolyte material and the host structure transition metal oxide do not show consistency; indicating that the crystal structure of the solid electrolyte product has changed during the preparation process. During the filler filling process, the lattice change inconsistent with the host structure will cause too high interfacial impedance, hinder the ion migration path, cannot effectively improve the ionic conductivity, and easily lead to unstable electrochemical performance. However, the solid electrolyte material prepared in Example 1 according to the optimization range of the present invention has X-ray diffraction peaks consistent with the host structure transition metal oxide, indicating a stable crystal structure, thus ensuring the ion migration rate and electrochemical stability of the battery.

[0106] It can be seen from Example 1 and Comparative Examples 3 and 4 that during the preparation of the solid electrolyte material, without adding transition metal oxides to construct the host structure, its ionic conductivity and electrochemical impedance are both poor, indicating that constructing the host structure with consistent XRD-derived peaks helps to improve the ionic conductivity of the material.

[0107] It can be seen from Examples 1-4 and Examples 5-9 that the solid electrolyte materials within the preferred element content and element ratio range exhibit excellent ionic conductivity and low interfacial impedance in the electrochemical performance test. Examples 5-9 further confirm that when the types, contents, and element ratios of the raw materials for preparing the solid electrolyte of the present invention vary within a certain range, the electrochemical performance of the solid electrolyte material remains stable. This indicates that the solid electrolyte material prepared in the examples of the present invention achieves high ionic conductivity with a low carrier concentration; and the prepared solid electrolyte material has high electrochemical performance in the electrochemical performance test of the battery.

[0108] It should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low-carrier oxohalide solid electrolyte material; the material has the general formula: A a M b OB c ; 0.3 < a < 0.7, 0.35 < b < 1.1, 1 < c < 4; The raw materials of the said material include a transition metal oxide M as the host structure z1 O z2 , an alkali metal halide A as the filler x1 B x2 and a transition metal halide M y1 B y2 ; the material A a M b OB c and the host structure M z1 O z2 have the same crystal structure; Among them, The alkali metal A includes one or more of lithium (Li), sodium (Na), and potassium (K); M includes transition metal elements with a valence of +4 or higher; the halogen atom B includes one or more of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I); the transition metal elements with a valence of +4 or higher include one or more of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), hafnium (Hf), zirconium (Zr), cobalt (Co), nickel (Ni), tantalum (Ta), tungsten (W), rhenium (Re), vanadium (V), niobium (Nb), tin (Sn), etc.; The mass percentage of A atoms in the material is selected from 1 - 3%, where the mass percentage refers to the proportion of the total mass of A atoms in the total mass of the material A a M b OB c The proportion of the total mass 2. The low-carrier oxohalide solid electrolyte material according to claim 1, characterized in that, The said A x1 B x2 , M z1 O z2 and M y1 B y2 wherein x1, x2, y1, y2, z1, z2 are all greater than 0; and x1 = x2.

3. The low-carrier oxohalide solid electrolyte material according to claim 1, characterized in that, The material A a M b OB c Selected from 1.2 < b / a < 2.

4. The low-carrier oxohalide solid electrolyte material according to claim 1, wherein The said Material A a M b OB c Selected from 0.5 < a < 0.6, 0.75 < b < 0.88, 2 < c < 3.5, 1.45 < b / a < 1.

65.

5. The low-carrier oxohalide solid electrolyte material according to claim 1, characterized in that, The transition metal oxide M z1 O z2 is selected from oxides of transition metal elements with a +5 valence state.

6. The low-carrier oxohalide solid electrolyte material according to claim 5, characterized in that, The transition metal oxide M z1 O z2 is selected from one or more of Ta2O5 and Nb2O5; the alkali metal halide A as the filler x1 B x2 is selected from one or more of LiCl, LiF, NaCl, and LiBr; the transition metal halide M as the filler y1 B y2 is selected from one or more of TaCl5, NbCl5, TaBr5, and NbBr5.

7. The low-carrier oxohalide solid electrolyte material according to claim 1, characterized in that, The low-carrier oxohalide solid electrolyte material is selected from Li 0.53 Nb 0.4 Ta 0.4 OCl 2.53 、Li 0.53 Ta 0.8 OCl2Br 0.53 、Li 0.42 Ta 0.32 Zr 0.32 OCl 1.26 、Li 0.66 Ta 0.5 Zr 0.5 OCl 3.16 、Li 0.6 TaOCl 3.79 、Li 0.405 Ta 0.5 OCl 1.9 、Li 0.325 Ta 0.6 OCl 1.325 、Li 0.56 Ta 0.8 OCl 2.56 、Li 0.4 Ta 0.7 OCl 1.9 、Li 0.53 Ta 0.8 OCl 1.32 、Li 0.53 Ta 0.8 OCl 2.53 、Li 0.53 Nb 0.8 OCl 2.53 、Li 0.53 Zr 0.8 OCl 2.53 、Li 0.66 Ta 0.5 Sn 0.5 OCl 3.16 、Na 0.53 Ta 0.8 OCl 2.53 、Na 0.53 Nb 0.8 OCl 2.53 、Na 0.53 Zr 0.8 OCl 2.53 、K 0.53 Ta 0.8 OCl 2.53 、K 0.53 Nb 0.8 OCl 2.53 、K 0.53 Zr 0.8 OCl 2.53 , Li 0.53 , Ta 0.8 , OClF 2.53 , Li 0.53 , Nb 0.8 , OClF 2.53 , Li 0.53 , Zr 0.8 , OClF 2.53 , Na 0.53 , Ta 0.8 , OClF 2.53 , Na 0.53 , Nb 0.8 , OClF 2.53 , Na 0.53 , Zr 0.8 , OClF 2.53 , K 0.53 , Ta 0.8 , OF 2.53 , K 0.53 , Nb 0.8 , OF 2.53 , K 0.53 , Zr 0.8 , OF 2.53 , Li 0.53 , Ta 0.8 , OBr 2.53 , Li 0.53 , Nb 0.8 , OBr 2.53 , Li 0.53 , Zr 0.8 , OBr 2.53 , Na 0.53 , Ta 0.8 , OBr 2.53 , Na 0.53 , Nb 0.8 , OBr 2.53 , Na 0.53 , Zr 0.8 , OBr 2.53 , K 0.53 , Ta 0.8 , OBr 2.53 , K 0.53 , Nb 0.8 , OBr 2.53 , K 0.53 , Zr 0.8 , OBr 2.53 among them.

8. The low-carrier oxohalide solid electrolyte material according to claim 3, characterized in that, The transition metal element M is selected from one or more of niobium (Nb) and tantalum (Ta); The halogen atom B is selected from one or more of Cl and Br; The alkali metal A is lithium (Li).

9. The low-carrier oxohalide solid electrolyte material according to claim 3, wherein The material A a M b OB c selected from Li a Ta b OCl c 、Li a Nb b OCl c 、Li a Ta b OBr c 、Li a Nb b OBr c one or more of; wherein, 0.3 < a < 0.7, 0.35 < b < 1.1, 1 < c < 4, 1.2 < b / a < 2.

10. The low-carrier oxohalide solid electrolyte material according to claim 1, wherein The ionic conductivity of the material is greater than 1 mS cm -1 .

11. The low-carrier oxohalide solid electrolyte material according to claim 1, wherein The mass percentage of A atoms in the said material is selected from 1 - 1.5%; 12. A preparation method of a low-carrier oxohalide solid electrolyte material; the said preparation method includes: Weigh A in a stoichiometric ratio of the required general formula under an inert gas x1 B x2 、M y1 B y2 、M z1 O z2 and mix them evenly to obtain a mixed material. The mixed material is prepared by mechanical ball milling to obtain a low-carrier oxohalide solid electrolyte material.

13. The preparation method according to claim 12, characterized in that, In the said preparation method, the inert gas includes one of argon or nitrogen; In the said preparation method, the parameter conditions of the mechanical ball milling method are selected as follows: rotation speed: 300 - 600 rpm; diameter of the ball milling beads: 1 - 10 mm; mass of the ball milling beads: mass of the mixed material = (10 - 80):1; ball milling time is greater than 10 h.

14. A battery, the said battery includes the low-carrier oxohalide solid electrolyte according to any one of claims 1 - 11, a positive electrode sheet, a negative electrode sheet, and a separator.

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