Electrolyte, method for producing the same, electrolyte film layer, and secondary battery

Abstract

The application provides an electrolyte, a preparation method of the electrolyte, an electrolyte film layer and a secondary battery. The electrolyte comprises multiple cation elements and anion elements. The multiple cation elements comprise a first cation element, a second cation element and a third cation element. The first cation element comprises at least one of lithium, sodium, potassium, iron, cobalt and nickel. The second cation element comprises at least one of group IIIA elements. The third cation element comprises at least one of group VA elements. The anion element comprises at least one of group VIA elements and halogen elements. The molar ratio of the group VA elements to the group IIIA elements is less than 5. The electrolyte can keep good contact between particles in the secondary battery, thereby reducing impedance, so that the secondary battery has good cycle performance.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to an electrolyte and its preparation method, an electrolyte membrane layer, and a secondary battery. Background Technology

[0002] Solid-state batteries are a strong alternative to liquid batteries due to their high energy density and safety. However, solid-state batteries also suffer from poor interfacial contact, leading to excessive impedance and decreased cycle performance. Summary of the Invention

[0003] This application provides an electrolyte and its preparation method, an electrolyte membrane, and a secondary battery. The electrolyte enables good contact between particles in the secondary battery, thereby reducing impedance and giving the secondary battery good cycle performance.

[0004] This application is achieved through the following technical solution: In a first aspect, embodiments of this application provide an electrolyte comprising a plurality of cation elements and anionic elements. The plurality of cation elements include a first cation element, a second cation element, and a third cation element. The first cation element includes at least one of lithium, sodium, potassium, iron, cobalt, and nickel. The second cation element includes at least one of group IIIA elements. The third cation element includes at least one of group VA elements. The anionic elements include at least one of group VIA elements and halogen elements. The molar ratio of group VA elements to group IIIA elements is less than or equal to 6.

[0005] In the above technical solution, the second cation element includes at least one of Group IIIA elements, and the third cation element includes at least one of Group VA elements. The molar ratio of Group VA elements to Group IIIA elements is less than or equal to 6. This allows the electrolyte to have adhesive properties and also allows it to have different morphologies. These different morphologies of electrolyte help maintain good contact between particles in the battery. Therefore, the electrolyte provided in this application, when applied to a secondary battery, helps to reduce the internal impedance of the secondary battery, thereby enabling the secondary battery to have good cycle performance.

[0006] In some possible implementations, the molar ratio of Group VA elements to Group IIIA elements is 0.1 to 6.

[0007] In some possible implementations, the electrolyte has the chemical formula A a M m Y y X xWhere A is the first cation element, M is the third cation element, Y is the second cation element, X is the anion element, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y≤6, 0.1≤x≤30.

[0008] In some possible implementations, the electrolyte has the chemical formula A a M m Y y D d Where A is the first cation element, M is the third cation element, Y is the second cation element, D is the anion element, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y≤6, 1≤d≤10.

[0009] In some possible implementations, the electrolyte has the chemical formula A a M m Y y X x D d Wherein, A is the first cation element, M is the third cation element, Y is the second cation element, X includes at least one element from the halogen group, D includes at least one element from group VIA, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y≤6, 0.1≤x≤30, and 1≤d≤10.

[0010] In some possible implementations, the electrolyte is in the form of at least one of emulsion, sol, gel, paste, ointment, clay, wax, block, sheet and granules.

[0011] In some possible implementations, Group VA elements include phosphorus.

[0012] In some possible implementations, Group IIIA elements include at least one of boron, aluminum, gallium, and indium.

[0013] In some possible implementations, the halogen element includes at least one of fluorine, chlorine, bromine, and iodine.

[0014] In some possible implementations, Group VIA elements include at least one of oxygen, sulfur, and selenium.

[0015] In some possible implementations, the electrolyte has the chemical formula A. a P m B y F x O d , where 0.1≤a≤6, 0.1≤m≤6, 0.1≤y≤2, 0.1≤x≤30, and 1≤d≤3.

[0016] In some possible implementations, 0.1 ≤ d / x ≤ 10.

[0017] In some possible implementations, the electrolyte has the chemical formula A. a P m Al y F x O d , where 0.1≤a≤3, 0.1≤m≤3, 0.1≤y≤2, 0.1≤x≤18, and 1≤d≤3.

[0018] In some possible implementations, the electrolyte includes a solid electrolyte with an average particle size of 100 nm to 10,000 nm.

[0019] In some possible implementations, the ionic conductivity of the electrolyte at 25°C is 0.001 mS / cm to 20 mS / cm.

[0020] Secondly, embodiments of this application provide a method for preparing an electrolyte as described in the first aspect of this application, the method comprising: The first precursor and the second precursor are ground or sintered to obtain an electrolyte. The first precursor includes an inorganic polyanionic salt precursor, and the cation in the inorganic polyanionic salt precursor includes at least one of lithium, sodium, potassium, iron, cobalt and nickel. The polyanion in the inorganic polyanionic salt precursor includes at least one of group IIIA and group VA elements, as well as at least one of halogen and group VIA elements. The second precursor includes at least one of group IIIA, group VA, halogen and group VIA elements.

[0021] In some possible implementations, the molar ratio of the inorganic polyanionic salt precursor to the second precursor is (0.1~6):1.

[0022] In some possible implementations, the electrolyte obtained by the grinding process has at least one of the following forms: emulsion, sol, gel, paste, ointment, clay, wax, block, flake, and granules.

[0023] In some possible implementations, the grinding process includes at least one of the following conditions: (I) The grinding speed is 200 r / min to 1000 r / min; (II) The grinding time is 0.5h~40h; (III) The grinding process includes at least one of ball milling, planetary milling or sand milling.

[0024] In some possible implementations, the electrolyte obtained by sintering treatment has at least one of the following forms: clay-like, wax-like, blocky, flake-like, and granular.

[0025] In some possible implementations, the sintering process includes at least one of the following conditions: (Ⅳ) The sintering temperature is 50℃~500℃; (V) The sintering time is 0.5h~10h; (VI) The heating and cooling rates of the sintering process are 1℃ / min to 10℃ / min; (VII) Sintering treatment methods include solid-state sintering.

[0026] In some possible implementations, the inorganic polyanionic salt precursors include LiClO3, LiClO4, LiOH, Li2SO4, LiNH2, Li2NH, LiNO3, Li3PO4, Li4P2O7, Li2PO3F, LiPO2F2, LiPF6, Li2CO3, Li2C2O4, Li2SiO3, Li4SiO4, LiBH4, LiB3H8, and Li2B2H. 12 , Li2BH4NH2, LiBO2, Li3BO3, Li2B4O7, LiBF4, LiAlH4, Li3AlH6, Li3AlF6, LiAlF4, LiAlO2, Li2WO4, LiVO3, Li3VO4, LiV3O8, LiNbO3, LiTaO3, Li2TiF6, Li2TiO3, Li4Ti5O 12 At least one of Li2ZrO3 and LiMg(BH4)3.

[0027] In some possible implementations, the second precursor includes at least one of oxides, sulfides, and halides.

[0028] In some possible embodiments, the oxides include Li₂O, Li₂O₂, Na₂O, Na₂O₂, K₂O, K₂O₂, KO₂, MgO, CaO, Sc₂O₃, Y₂O₃, La₂O₃, TiO₂, ZrO₂, HfO₂, V₂O₃, V₂O₅, Nb₂O₅, Ta₂O₅, Cr₂O₃, CrO₂, CrO₃, MoO₃, WO₂, WO₃, MnO, MnO₂, TcO₂, ReO₂, ReO₃, Re₂O₇, Fe. O, Fe2O3, Fe3O4, CoO, Co2O3, Co3O4, Ni2O3, Cu2O, CuO, Ag2O, Au2O3, ZnO, B2O3, Al2O3, Ga2O3, In2O3, Tl2O3 , at least one of SiO2, GeO, GeO2, SnO, SnO2, P2O3, P2O5, Sb2O3, Sb2O5, Bi2O3, SeO2, SeO3, TeO2, TeO3, I2O4, I2O5; Sulfides include Li2S, Na2S, K2S, MgS, CaS, Sc2S3, Y2S3, La2S3, TiS2, ZrS2, HfS2, V2S3, V2S5, Nb2S5, Ta2S 5. Cr2S3, CrS2, CrS3, MoS3, WS2, WS3, MnS, MnS2, TcS2, ReS2, ReS3, Re2S7, FeS, Fe2S3, Fe3S4, CoS , Co2S3, Co3S4, Ni2S3, Cu2S, CuS, Ag2S, Au2S3, ZnS, B2S3, Al2S3, Ga2S3, In2S3, Tl2S3, SiS2, Ge At least one of S, GeS2, SnS, SnS2, P2S3, P2S5, Sb2S3, Sb2S5, Bi2S3, SeS2, SeS3, TeS2, TeS3, I2S4, and I2S5; Halides include LiX, NaX, KX, CsX, MgX2, CaX2, YX3, LaX3, TiX2, TiX4, ZrX2, ZrX4, HfX2, HfX4, VX2, VX5, NbX2, NbX5, TaX2, TaX5, CrX2, CrX3, MoX4, MoX6, WX4, WX5, WX6, MnX2, MnX3, FeX2, FeX3, CoX2, NiX2, CuX, CuX2, AgX, AuX, AuX3, ZnX2, BX3, AlX3, GaX3, InX3, TlX, TlX3, GeX4, SnX2, SnX4, PX3, PX5, SbX3, BiX3, SeX4, BrF3, IF5, ICl, ICl3, IBr, where X includes at least one of the halogen elements.

[0029] In some possible implementations, the inorganic polyanionic salt precursor includes at least one of LiPF6, LiBF4, LiBO2, and LiAlF4; And / or, the oxides include at least one of P2O5 and B2O3; And / or, the sulfides include at least one of P2S5 and B2S3.

[0030] In some possible implementations, the first precursor comprises an organic polyanionic salt.

[0031] In some possible implementations, the organic polyanionic salt includes at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalateborate) and lithium difluorooxalateborate.

[0032] Thirdly, embodiments of this application provide an electrolyte membrane layer, which includes the electrolyte of the first aspect of this application or the electrolyte prepared by the preparation method of the second aspect of this application.

[0033] In some possible implementations, the electrolyte membrane layer further includes a carrier having a porous structure, with the electrolyte located in the pores of the porous structure.

[0034] Fourthly, embodiments of this application provide a secondary battery, which includes a positive electrode, a negative electrode, and an electrolyte membrane. The positive electrode includes a positive current collector and a positive electrode membrane disposed on at least one side of the positive current collector. The negative electrode includes a negative current collector and a negative electrode membrane disposed on at least one side of the negative current collector. The electrolyte membrane is located between the positive electrode and the negative electrode. At least one of the positive electrode membrane, the negative electrode membrane, and the electrolyte membrane comprises the electrolyte of the first aspect of this application or the electrolyte prepared by the preparation method of the second aspect of this application.

[0035] In some possible implementations, the positive electrode film layer includes an electrolyte, a positive electrode active material, and a positive electrode conductive agent. Based on the mass of the positive electrode film layer, the mass content of the electrolyte is 2.5% to 30%, the mass content of the positive electrode active material is 50% to 95%, and the mass content of the positive electrode conductive agent is 2.5% to 20%.

[0036] In some possible implementations, the negative electrode film layer includes an electrolyte, a negative electrode active material, and a negative electrode conductive agent. Based on the total mass of the negative electrode film layer, the mass content of the electrolyte is 2.5% to 30%, the mass content of the negative electrode active material is 50% to 95%, and the mass content of the negative electrode conductive agent is 2.5% to 20%.

[0037] In some possible implementations, the negative electrode active material includes carbon-based negative electrode active materials and / or silicon-containing negative electrode active materials.

[0038] In some possible implementations, the carbon-based anode active material includes at least one of artificial graphite, natural graphite, graphitized carbon fiber, amorphous carbon, soft carbon, and hard carbon.

[0039] In some possible implementations, the secondary battery further includes a first interface layer comprising the electrolyte described above, the first interface layer being located between the positive electrode and the electrolyte membrane layer.

[0040] In some possible implementations, the secondary battery further includes a second interface layer comprising the electrolyte described above, the second interface layer being located between the negative electrode and the electrolyte membrane layer.

[0041] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0042] To better describe and illustrate the embodiments, examples, or models provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments, examples, or models, or the best mode of these applications as currently understood. It should also be noted that the drawings are drawn in a simplified form and are only used to facilitate and clarify the illustration of this application. The various dimensions of each component shown in the drawings are arbitrarily shown and may be precise or not drawn to actual scale. For example, the dimensions of components are appropriately exaggerated in some places in the drawings to make the illustration clearer. Unless otherwise specified, the components in the drawings are not drawn to scale. The drawings of this application do not limit every dimension of every component. Furthermore, the same reference numerals are used to denote the same components throughout all the drawings. In the drawings: Figure 1 Different morphological diagrams of electrolytes provided for embodiments of this application.

[0043] Figure 2 This is a schematic diagram of the electrolyte to the electrolyte membrane layer provided for an embodiment of this application.

[0044] Figure 3 An electrolyte membrane layer diagram provided for an embodiment of this application.

[0045] Figure 4 An electrolyte membrane layer diagram provided for another embodiment of this application. Detailed Implementation

[0046] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0047] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having" and any variations thereof in the description, claims and foregoing drawings of this application are intended to cover non-exclusive inclusion.

[0048] The terms "first," "second," etc., in the specification, claims, or the accompanying drawings of this application are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0049] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0050] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0051] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0052] In this application, "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0053] The ion transport pathways within solid-state batteries rely on rigid interfacial contacts formed between solid particles. This contact state requires high external pressure to maintain stability. However, during actual charge-discharge cycles, the active electrode material undergoes volume deformation due to the insertion and extraction of active ions. Even with sustained high external pressure, this periodic expansion and contraction can still cause cracks to appear in the originally tight solid-state interface. As these interfacial cracks extend further, the ion transport pathways are blocked, leading to increased battery impedance. This increased impedance further triggers capacity decay, ultimately resulting in a decline in the cycle performance of the solid-state battery.

[0054] In view of this, the present application provides an electrolyte and its preparation method, an electrolyte membrane layer and a secondary battery. The electrolyte can maintain good contact between particles in the secondary battery, thereby helping to reduce impedance and thus enabling the secondary battery to have good cycle performance.

[0055] [Electrolytes] This application provides an electrolyte comprising a plurality of cations and anions. The plurality of cations include a first cation, a second cation, and a third cation. The first cation includes at least one of lithium, sodium, potassium, iron, cobalt, and nickel. The second cation includes at least one of Group IIIA elements. The third cation includes at least one of Group VA elements. The anion includes at least one of halogens and Group VIA elements. The molar ratio of the Group VA elements to the Group IIIA elements is less than or equal to 6.

[0056] In this application, the "electrolyte" can be identified using methods known in the art, such as using inductively coupled plasma spectrometry (ICP) to determine the types of elements in the electrolyte and the molar ratio of each element, thereby determining the chemical formula.

[0057] In the electrolyte provided in the embodiments of this application, the second cation includes at least one element from Group IIIA, and the third cation includes at least one element from Group VA. The molar ratio of the Group VA element to the Group IIIA element is less than or equal to 6. This allows the electrolyte to have adhesive properties and also allows it to have different morphologies. These different morphologies of the electrolyte help maintain good contact between particles in the battery. Therefore, when the electrolyte provided in this application is used in a secondary battery, it is beneficial to reduce the internal impedance of the secondary battery, thereby enabling the secondary battery to have good cycle performance.

[0058] In some implementations, the molar ratio of Group VA elements to Group IIIA elements is 0.1 to 6.

[0059] In the above embodiments, the molar ratio of Group VA elements and Group IIIA elements is controlled within the above range, which allows them to have different forms while also having good ionic conductivity.

[0060] For example, the molar ratio of Group VA elements to Group IIIA elements can be, but is not limited to, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, and 2.8. 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6 or any value within either of its two ranges.

[0061] In some embodiments, the electrolyte has the chemical formula A. a M m Y y X x Where A is the first cation element, M is the third cation element, Y is the second cation element, X is the anion element, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y≤6, 0.1≤x≤30.

[0062] In some embodiments, the electrolyte has the chemical formula A. a M m Y y D d Where A is the first cation element, M is the third cation element, Y is the second cation element, D is the anion element, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y≤6, 1≤d≤10.

[0063] In some embodiments, the electrolyte has the chemical formula A. a M m Y y X x D d Wherein, A is the first cation element, M is the third cation element, Y is the second cation element, X includes at least one element from the halogen group, D includes at least one element from group VIA, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y≤6, 0.1≤x≤30, and 1≤d≤10.

[0064] In the above embodiments, the electrolyte includes the above chemical formula, which can make it have different forms and also have a high electrochemical window, so as to improve the energy density of the battery using it.

[0065] As an example, the electrolyte can be, but is not limited to, LiPB2F6O3, Li 1.5 P 1.5 B2F9O3, Li 1.8 P 1.8 B2F 10.8 O3, Li2P2B2F 12 O3, Li 2.5 P 2.5 B2F 15 O3 and Li4P4B2F 24 At least one of S3.

[0066] In some embodiments, the electrolyte is in the form of at least one of emulsion, sol, gel, paste, ointment, clay, wax, block, flake and granules.

[0067] In this article, "emulsion-like" refers to a mixture in which a liquid phase containing electrolytes is dispersed in another liquid phase by mechanical force, forming a mixture that has both ionic conductivity and fluid properties.

[0068] In this paper, "sol-like" refers to a colloidal dispersion system formed by solid particles dispersed in a liquid medium.

[0069] In this paper, "gel-like" refers to the formation of a network in which liquid electrolytes are loaded onto a matrix, combining the integrity of a solid morphology with the ionic conductivity close to that of a liquid.

[0070] In this article, "paste-like" refers to a thick slurry formed by mixing a solid electrolyte with a small amount of liquid electrolyte, which is easy to coat or fill.

[0071] In this article, "clay-like" refers to a soft solid material with a water content between solid and liquid states and excellent plasticity.

[0072] In this article, "waxy" refers to a soft, malleable solid with a low melting point at room temperature, exhibiting a waxy luster and a slippery feel.

[0073] In this paper, "blocky" refers to a solid aggregate with a visible three-dimensional macroscopic size and a regular or irregular shape.

[0074] In this paper, "sheet-like" refers to solid aggregates with three-dimensional macroscopic dimensions visible to the naked eye and regular or irregular shapes.

[0075] In this paper, "granular" refers to aggregates of discrete solid particles with tiny sizes (typically micrometers to millimeters).

[0076] In the embodiments of this application, "room temperature" generally refers to 4℃ to 35℃, and may refer to 20℃ ± 5℃. In some embodiments, room temperature refers to 20℃ to 30℃.

[0077] In some implementations, Group VA elements include phosphorus (P).

[0078] In some embodiments, Group IIIA elements include at least one of boron (B), aluminum (Al), gallium (Ga), and indium (In).

[0079] In the above embodiments, the inclusion of Group IIIA elements can give the electrolyte a better high viscosity, thereby reducing the amount of binder used and increasing the amount of active material used, which is beneficial to improving the energy density of the battery.

[0080] In some embodiments, the halogen element includes at least one of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

[0081] In the above embodiments, the halogen elements include the aforementioned elements, which is beneficial for improving the chemical stability of the electrolyte.

[0082] In some embodiments, Group VIA elements include at least one of oxygen (O), sulfur (S), and selenium (Se).

[0083] In the above embodiments, the VIA group elements include the aforementioned elements, which is beneficial for adjusting their morphology.

[0084] In some embodiments, the electrolyte has the chemical formula A. a P m B y F x O d , where 0.1≤a≤6, 0.1≤m≤6, 0.1≤y≤2, 0.1≤x≤30, and 1≤d≤3.

[0085] In the above embodiments, the electrolyte has the above chemical formula, which allows it to have more forms and a wider electrochemical window.

[0086] In some implementations, 0.1 ≤ d / x ≤ 10.

[0087] In the above embodiments, controlling d / x within the above range helps the electrolyte to have more morphologies and broaden the electrochemical window.

[0088] In some embodiments, the electrolyte has the chemical formula A. a P m Al y F x O d , where 0.1≤a≤3, 0.1≤m≤3, 0.1≤y≤2, 0.1≤x≤18, and 1≤d≤3.

[0089] In some embodiments, the electrolyte includes a solid electrolyte with an average particle size of 100 nm to 10,000 nm.

[0090] In this paper, the average particle size of solid electrolytes has a meaning known in the art, and it can be determined by any known test method in the art. For example, the average particle size can be obtained by using an instrument for particle size distribution laser diffraction (Mastersizer 3000E laser particle size analyzer from Malvern Instruments Ltd.) in accordance with GB / T19077-2016.

[0091] In the above embodiments, the average particle size of the solid electrolyte is within the above range, which can form a good gradation with the active material particles, so as to maintain good contact between the solid electrolyte and the active material particles.

[0092] In some embodiments, the ionic conductivity of the electrolyte at 25°C is 0.001 mS / cm to 20 mS / cm.

[0093] In this paper, 120 mg of electrolyte was poured into a 10 mm diameter tableting mold and pressed into a dense disc at 350 MPa. Then, a 10 mm diameter cylindrical stainless steel current collector was used to clamp the electrolyte disc within the mold at 120 MPa. The current collector was then connected to an electrochemical workstation, and electrochemical impedance spectroscopy (EIS) was performed on the electrolyte disc at a bias voltage of 10 mV and a frequency range of 10 Hz to 106 Hz. The resistance R was recorded as the intersection of the electrochemical impedance spectrum curve from high frequency to low frequency with the Z' axis. The ionic conductivity could be calculated using formula (1). σ=1 / R d / A (1); Where d is the thickness of the electrolyte sheet in cm; A is the contact area between the electrolyte sheet and the current collector in cm². 2 σ is the ionic conductivity, with units of S / cm.

[0094] [Methods for preparing electrolytes] This application provides a method for preparing the above-mentioned electrolyte, the method comprising: The first precursor and the second precursor are ground or sintered to obtain an electrolyte. The first precursor includes an inorganic polyanionic salt precursor, and the cation in the inorganic polyanionic salt precursor includes at least one of lithium, sodium, potassium, iron, cobalt and nickel. The polyanion in the inorganic polyanionic salt precursor includes at least one of group IIIA and group VA elements, as well as at least one of halogen and group VIA elements. The second precursor includes at least one of group IIIA, group VA, halogen and group VIA elements.

[0095] In the above embodiments, the preparation method is simple and can prepare electrolytes in one step by grinding or sintering, and the preparation cost is low.

[0096] In some embodiments, the molar ratio of the inorganic polyanionic salt precursor to the second precursor is (0.1~6):1. Exemplary examples include, but are not limited to, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, etc. 1, 3.0:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4.0:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1, 5.0:1, 5.1:1, 5.2:1, 5.3:1, 5.4:1, 5.5:1, 5.6:1, 5.7:1, 5.8:1, 5.9:1, 6.0:1, or any value within either of these two ranges.

[0097] In the above embodiments, electrolytes of different forms can be prepared by controlling the molar ratio of the inorganic polyanionic salt precursor and the second precursor within the above range.

[0098] In some embodiments, the electrolyte obtained by the grinding process is in at least one of the following forms: emulsion, sol, gel, paste, ointment, clay, wax, block, flake, and granules.

[0099] In some embodiments, the grinding speed is 200 r / min to 1000 r / min. Exemplary examples include, but are not limited to, 200 r / min, 220 r / min, 240 r / min, 260 r / min, 280 r / min, 300 r / min, 320 r / min, 340 r / min, 360 r / min, 380 r / min, 400 r / min, 420 r / min, 440 r / min, 460 r / min, 480 r / min, 500 r / min, 520 r / min, 540 r / min, 560 r / min, 580 r / min, and 600 r / min. 0 r / min, 620 r / min, 640 r / min, 660 r / min, 680 r / min, 700 r / min, 720 r / min, 740 r / min, 760 r / min, 780 r / min, 800 r / min, 820 r / min, 840 r / min, 860 r / min, 880 r / min, 900 r / min, 920 r / min, 940 r / min, 960 r / min, 980 r / min, 1000 r / min, or any value within either of these two ranges.

[0100] In some embodiments, the grinding process takes 0.5 hours to 40 hours. For example, the grinding process may be, but is not limited to, 0.5 hours, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours, 36 hours, 38 hours, 40 hours, or any value within both of these ranges.

[0101] In the above embodiments, controlling the grinding time within the above range is beneficial for forming an electrolyte with high ionic conductivity.

[0102] In some embodiments, the grinding process includes at least one of ball milling, planetary milling, or sand milling.

[0103] In some embodiments, the electrolyte obtained by sintering treatment has at least one of the following forms: clay-like, waxy, blocky, flake-like, and granular.

[0104] In some embodiments, the sintering temperature is 50°C to 500°C. Exemplary examples include, but are not limited to, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, and 230°C. 0℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, or any value within either of these two ranges.

[0105] In some embodiments, the sintering time is 0.5h to 10h. For example, the sintering time may be, but is not limited to, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, or any value within both of these ranges.

[0106] In some embodiments, the heating and cooling rates of the sintering process are 1°C / min to 10°C / min. The heating and cooling rates of the sintering process may be, but are not limited to, 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, or any value within the range of two such values.

[0107] In some implementations, the sintering process includes solid-state sintering.

[0108] In some embodiments, the inorganic polyanionic salt precursor includes LiClO3, LiClO4, LiOH, Li2SO4, LiNH2, Li2NH, LiNO3, Li3PO4, Li4P2O7, Li2PO3F, LiPO2F2, LiPF6, Li2CO3, Li2C2O4, Li2SiO3, Li4SiO4, LiBH4, LiB3H8, and Li2B2H. 12, Li2BH4NH2, LiBO2, Li3BO3, Li2B4O7, LiBF4, LiAlH4, Li3AlH6, Li3AlF6, LiAlF4, LiAlO2, Li2WO4, LiVO3, Li3VO4, LiV3O8, LiNbO3, LiTaO3, Li2TiF6, Li2TiO3, Li4Ti5O 12 At least one of Li2ZrO3 and LiMg(BH4)3.

[0109] In some embodiments, the second precursor includes at least one of oxides, sulfides, and halides.

[0110] In some embodiments, the oxides include Li₂O, Li₂O₂, Na₂O, Na₂O₂, K₂O, K₂O₂, KO₂, MgO, CaO, Sc₂O₃, Y₂O₃, La₂O₃, TiO₂, ZrO₂, HfO₂, V₂O₃, V₂O₅, Nb₂O₅, Ta₂O₅, Cr₂O₃, CrO₂, CrO₃, MoO₃, WO₂, WO₃, MnO, MnO₂, TcO₂, ReO₂, ReO₃, Re₂O₇, FeO, Fe2O3, Fe3O4, CoO, Co2O3, Co3O4, Ni2O3, Cu2O, CuO, Ag2O, Au2O3, ZnO, B2O3, Al2O3, Ga2O3, In2O3, Tl2O3, At least one of SiO2, GeO, GeO2, SnO, SnO2, P2O3, P2O5, Sb2O3, Sb2O5, Bi2O3, SeO2, SeO3, TeO2, TeO3, I2O4, and I2O5.

[0111] In some embodiments, the sulfides include Li₂S, Na₂S, K₂S, MgS, CaS, Sc₂S₃, Y₂S₃, La₂S₃, TiS₂, ZrS₂, HfS₂, V₂S₃, V₂S₅, Nb₂S₅, Ta₂S₅, Cr₂S₃, CrS₂, CrS₃, MoS₃, WS₂, WS₃, MnS, MnS₂, TcS₂, ReS₂, ReS₃, Re₂S₇, FeS, Fe₂S₃, Fe₃S 4. CoS, Co2S3, Co3S4, Ni2S3, Cu2S, CuS, Ag2S, Au2S3, ZnS, B2S3, Al2S3, Ga2S3, In2S3, Tl2S3, SiS2, At least one of GeS, GeS2, SnS, SnS2, P2S3, P2S5, Sb2S3, Sb2S5, Bi2S3, SeS2, SeS3, TeS2, TeS3, I2S4, and I2S5.

[0112] In some embodiments, the halides include LiX, NaX, KX, CsX, MgX2, CaX2, YX3, LaX3, TiX2, TiX4, ZrX2, ZrX4, HfX2, HfX4, VX2, VX5, NbX2, NbX5, TaX2, TaX5, CrX2, CrX3, MoX4, MoX6, WX4, WX5, WX6, MnX2, MnX3, FeX2, FeX3, CoX2, NiX2, CuX, CuX2, AgX, AuX, AuX3, ZnX2, BX3, AlX3, GaX3, InX3, TlX, TlX3, GeX4, SnX2, SnX4, PX3, PX5, SbX3, BiX3, SeX4, BrF3, IF5, ICl, ICl3, IBr, where X includes at least one of the halogen elements.

[0113] In some embodiments, the inorganic polyanionic salt precursor includes at least one of LiPF6, LiBF4, LiBO2, and LiAlF4.

[0114] In some embodiments, the oxide includes at least one of P2O5 and B2O3.

[0115] In some embodiments, the sulfide includes at least one of P2S5 and B2S3.

[0116] In some embodiments, the first precursor comprises an organic polyanionic salt.

[0117] In some embodiments, the organic polyanionic salt includes at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalateborate) and lithium difluorooxalateborate.

[0118] [Electrolyte membrane layer] like Figures 2-4 As shown, an embodiment of this application provides an electrolyte membrane layer, which includes the electrolyte of the first aspect of this application or the electrolyte prepared by the preparation method of the second aspect of this application.

[0119] In some embodiments, the electrolyte membrane layer further includes a carrier having a porous structure, with the electrolyte located in the pores of the porous structure.

[0120] In the above embodiments, the carrier can be a separating membrane, a filter membrane, a filter screen, etc. In some embodiments, the carrier material can be polypropylene, polytetrafluoroethylene, etc.

[0121] In some embodiments, the thickness of the electrolyte membrane layer is 5µm to 1000µm.

[0122] In this paper, the test method for "electrolyte membrane thickness" includes: taking a secondary battery at 100% SOC, taking a combination of a positive electrode, an electrolyte membrane, and a negative electrode, cutting it by ion beam cutting, and then taking pictures of the cut surface using a scanning electron microscope (e.g., magnification 1000x). Taking any ten pictures, in each picture, along the length of the cut surface, randomly selecting five positions, and measuring the thickness of the electrolyte membrane at the five positions. There are a total of 50 thickness values ​​in the five pictures. The average of the 50 thickness values ​​is the thickness of the electrolyte membrane.

[0123] As an example, the thickness of the electrolyte membrane layer may be, but is not limited to, any value within the range of 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 140 μm, 150 μm, 200 μm, 500 μm, 1000 μm, and both of these ranges.

[0124] In the process of preparing the electrolyte membrane layer, a small amount of binder may also be mixed in, for example, a binder with a mass ratio of 1% to 20%. Further, the binder includes at least one of polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0125] [Rechargeable Battery] This application provides a secondary battery comprising a positive electrode, a negative electrode, and an electrolyte membrane. The positive electrode includes a positive current collector and a positive electrode membrane disposed on at least one side of the positive current collector. The negative electrode includes a negative current collector and a negative electrode membrane disposed on at least one side of the negative current collector. The electrolyte membrane is located between the positive electrode and the negative electrode. At least one of the positive electrode membrane, the negative electrode membrane, and the electrolyte membrane comprises the electrolyte described above or an electrolyte prepared by the method described above.

[0126] In this document, "a positive electrode film layer disposed on at least one side of the positive electrode current collector" means that: the positive electrode current collector has two sides opposite to each other in its own thickness direction, and a positive electrode film layer can be formed on one side of the positive electrode current collector, or a positive electrode film layer can be formed on both sides of the positive electrode current collector. In the same electrode assembly, a positive electrode film layer can be formed on one side of some positive electrode current collectors, and a positive electrode film layer can be formed on both sides of some positive electrode current collectors; or a positive electrode film layer can be formed on one side of all positive electrode current collectors in the same electrode assembly; or a positive electrode film layer can be formed on both sides of all positive electrode current collectors in the same electrode assembly. This application does not limit this.

[0127] In this document, "a negative electrode film layer disposed on at least one side of the negative electrode current collector" means that: the negative electrode current collector has two sides opposite to each other in its own thickness direction, and a negative electrode film layer can be formed on one side of the negative electrode current collector, or a negative electrode film layer can be formed on both sides of the negative electrode current collector. In the same electrode assembly, a negative electrode film layer can be formed on one side of some negative electrode current collectors, and a negative electrode film layer can be formed on both sides of some negative electrode current collectors; or a negative electrode film layer can be formed on one side of all negative electrode current collectors in the same electrode assembly; or a negative electrode film layer can be formed on both sides of all negative electrode current collectors in the same electrode assembly. This application does not limit this.

[0128] In some embodiments, the positive electrode film layer includes an electrolyte and a positive electrode active material, wherein the mass content of the electrolyte is 2.5% to 25% and the mass content of the positive electrode active material is 50% to 95% based on the mass of the positive electrode film layer.

[0129] In this application, the "mass content of electrolyte in the positive electrode film" can be determined using any test method known in the art. For example, the test method could be: take a secondary battery at 100% SOC and disassemble it, take a positive electrode, scrape powder from the dry positive electrode film, and test the content of each element in the scraped powder according to the electrolyte element content detection method in T / CSAE 479-2025 "Chemical Analysis Methods for Sulfide Solid Electrolytes", and determine the electrolyte content based on the measured mass ratio of each element.

[0130] In this paper, the "mass percentage of positive electrode active material in the positive electrode film" can be determined using any known testing method in the art. For example, the testing method could be as follows: Take a secondary battery at 100% SOC and disassemble it. After removing the positive electrode sheet, scrape off the powder and weigh it, recording the weight as m1. Dissolve the binder in the positive electrode powder thoroughly with xylene, a weakly polar solvent. After three dissolution and filtration processes, add ethanol solvent to the remaining powder to remove the electrolyte. After three dissolution and filtration processes, decompose the remaining powder at 400°C to volatilize the residual solvent and pyrolyze the remaining organic binder. Further heat to 800°C to remove the positive electrode conductive agent, then weigh the remaining powder and record the weight as m2. m2 is the mass of the positive electrode active material, and m2 / m1 is the mass percentage of the positive electrode active material in the positive electrode film.

[0131] In the above embodiments, when the mass ratio of the positive electrode active material in the positive electrode film layer is within the above range, and the above electrolyte is added to the positive electrode film layer, not only can the energy density of the secondary battery be improved, but the mass ratio of the binder can also be reduced to reduce the risk of the positive electrode film layer falling off and thus enhance its ionic conductivity.

[0132] In some embodiments, the positive electrode active material may include lithium iron phosphate, lithium manganese iron phosphate, lithium cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, etc.

[0133] In some embodiments, the positive electrode film layer further includes a positive electrode conductive agent, which includes at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. Based on the mass of the positive electrode film layer, the mass percentage of the positive electrode conductive agent is 2.5% to 25%.

[0134] In some embodiments, the positive electrode film layer also includes a positive electrode binder, wherein the positive electrode binder accounts for 0.1% to 15% of the mass of the positive electrode film layer.

[0135] As an example, the positive electrode binder includes at least one of polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, and tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer.

[0136] In some embodiments, the negative electrode film layer includes an electrolyte, a negative electrode active material, and a negative electrode conductive agent. Based on the total mass of the negative electrode film layer, the mass content of the electrolyte is 2.5% to 25%, the mass content of the negative electrode active material is 50% to 95%, and the mass content of the negative electrode conductive agent is 2.5% to 25%.

[0137] In some embodiments, the negative electrode active material includes carbon-based negative electrode active materials and / or silicon-containing negative electrode active materials.

[0138] In some embodiments, the carbon-based anode active material includes at least one of artificial graphite, natural graphite, graphitized carbon fiber, amorphous carbon, soft carbon, and hard carbon.

[0139] In some embodiments, the negative electrode conductive agent includes at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0140] In some embodiments, the negative electrode film layer further includes a negative electrode binder, wherein the negative electrode binder accounts for 0.1% to 15% of the mass of the negative electrode film layer.

[0141] As an example, the negative electrode binder includes at least one of hydrogenated nitrile rubber, polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0142] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0143] In some embodiments, the secondary battery further includes a first interface layer, which includes the electrolyte described in the first aspect, and the first interface layer is located between the positive electrode and the electrolyte film layer.

[0144] In some embodiments, the secondary battery further includes a second interface layer, which includes the electrolyte described in the first aspect, and the second interface layer is located between the negative electrode and the electrolyte membrane layer.

[0145] I. Implementation Examples The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0146] Example 1 This embodiment provides a method for preparing an electrolyte, the method comprising: Lithium hexafluorophosphate (LiPF6) and boron trioxide (B2O3) were mixed in a 1:1 molar ratio and then ground to obtain an electrolyte with the chemical formula LiPB2F6O3. The grinding speed was 1000 r / min and the grinding time was 40 h.

[0147] Examples 2-6 and Comparative Examples 1-2 The difference between Examples 2-6 and Comparative Examples 1-2 and Example 1 is that electrolytes of different forms were prepared by adjusting the molar ratio of LiPF6 and B2O3.

[0148] Examples 7-8 The difference between Examples 7 and 8 and Example 1 is that the electrolyte is prepared by adjusting the grinding time.

[0149] Examples 9-10 The difference between Examples 9 and 10 and Example 2 is that the electrolyte is prepared by adjusting the grinding time.

[0150] Examples 11-12 The difference between Examples 11-12 and Example 3 is that the electrolyte is prepared by adjusting the grinding time.

[0151] Example 13 This embodiment provides a method for preparing an electrolyte, the method comprising: Lithium hexafluorophosphate (LiPF6) and boron trioxide (B2O3) were mixed in a 1:1 molar ratio and sintered to obtain an electrolyte with the chemical formula LiPB2F6O3. The sintering temperature was 500℃ and the sintering time was 10h.

[0152] Example 14 This embodiment provides a method for preparing an electrolyte, the method comprising: Lithium hexafluorophosphate (LiPF6) and boron trioxide (B2O3) were mixed in a molar ratio of 2:1 and then sintered to obtain the chemical formula Li2P2B2F. 12 The electrolyte is O3, wherein the sintering temperature is 500℃ and the sintering time is 10h.

[0153] Examples 15-18 The difference between Examples 15-18 is that the electrolyte was prepared by adjusting the types of raw materials.

[0154] Table 1 lists the main parameters for the preparation of electrolytes in Examples 1-18 and Comparative Examples 1-2.

[0155] Table 1: Preparation parameters of electrolytes in Examples 1-18 and Comparative Examples 1-2

[0156] Note: a:b represents the molar ratio of the inorganic polyanionic salt precursor to the second precursor.

[0157] Test section The electrolytes in Examples 1-18 and Comparative Examples 1-2 were tested respectively, and the test results are shown in Table 2. The specific test methods are as follows: (1) Chemical formula test of electrolytes Inductively coupled plasma spectrometry (ICP) is used to determine the types of elements in the electrolyte and the molar ratio of each element, thereby determining the chemical formula.

[0158] (2) Electrolyte speciation test The macroscopic morphology of electrolytes can be directly observed under standard illumination, and can also be observed using auxiliary tools, such as standard light source boxes, digital cameras, and optical microscopes. Figure 1 As shown, the electrolyte forms in Examples 1 to 6 are illustrated in turn.

[0159] (3) Electrolyte ionic conductivity test 100 mg of electrolyte was poured into a 10 mm diameter tableting mold and pressed into a dense disc at 350 MPa. Then, a 10 mm diameter cylindrical stainless steel current collector was used to clamp the electrolyte disc within the mold at 120 MPa. The current collector was then connected to an electrochemical workstation with a bias voltage of 10 mV and a frequency range of 10 Hz to 10 Hz. 6 Electrochemical impedance spectroscopy (EIS) was performed on the electrolyte sheet within the Hz range. The intersection point of the electrochemical impedance spectrum curve from the high-frequency band to the low-frequency band with the Z' axis was recorded as the resistance value R. The ionic conductivity can be calculated using formula (1): σ=1 / R d / A (1); Where d is the thickness of the electrolyte sheet in cm; A is the contact area between the electrolyte sheet and the current collector in cm². 2 σ is the ionic conductivity, with units of S / cm.

[0160] (4) Impedance test The impedance was obtained by fitting the Nyquist curve obtained from the EIS test. The test temperature was 25℃.

[0161] Table 2: Electrolyte test results in Experimental Examples 1-18 and Comparative Examples 1-2

[0162] Note: m / y represents the molar ratio of Group VA elements to Group IIIA elements, and / or the molar ratio of Group VA elements to Group IVA elements; the electrochemical window in Experimental Examples 3-4 is as high as 4.5V.

[0163] According to Table 1, comparing the test results of Examples 1-6 and Comparative Examples 1-2, it can be seen that in the electrolyte provided by the embodiments of this application, the second cation element includes at least one of Group IIIA elements, the third cation element includes at least one of Group VA elements, and the molar ratio of Group VA elements to Group IIIA elements is less than or equal to 6, which can make the electrolyte have different forms and also have high ionic conductivity and low impedance, so that when it is applied to a battery, the battery has good cycle performance.

[0164] Comparing the test results of Examples 1 and 7-8, it can be seen that as the grinding time increases, the ionic conductivity of the prepared electrolyte gradually increases and the impedance gradually decreases. Similarly, the same conclusion can be drawn from the test results of Examples 2 and 9-10, and Examples 4 and 11-12.

[0165] Comparing the test results of Examples 7 and 13, it can be seen that the emulsion electrolyte prepared by grinding has higher ionic conductivity and lower impedance than the wax electrolyte prepared by sintering.

[0166] Comparing the test results of Examples 3 and 14, it can be seen that the ointment-like electrolyte prepared by grinding has higher ionic conductivity and lower impedance than the block electrolyte prepared by sintering.

[0167] Comparing the test results of Examples 1 and 15-16, it can be seen that the sol-like electrolyte prepared by using sulfur as an anion has higher ionic conductivity and lower impedance than the emulsion electrolyte prepared by using oxygen as an anion or the particulate electrolyte prepared by using fluorine.

[0168] Comparing the test results of Example 1 and Example 17, it can be seen that the electrolyte does not contain halogen elements, so the ionic conductivity is relatively low and the impedance is higher.

[0169] Comparing the test results of Examples 17 and 18, it can be seen that the electrolyte prepared in Example 18 contains halogen elements, which results in higher ionic conductivity and lower impedance.

[0170] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electrolyte, characterized in that, The electrolyte comprises multiple cation and anion elements. The multiple cation elements include a first cation element, a second cation element, and a third cation element. The first cation element includes at least one of lithium, sodium, potassium, iron, cobalt, and nickel. The second cation element includes at least one of Group IIIA elements. The third cation element includes at least one of Group VA elements. The anion element includes at least one of Group VIA and halogen elements. The molar ratio of the Group VA element to the Group IIIA element is less than 5.

2. The electrolyte according to claim 1, characterized in that, The molar ratio of the Group VA element to the Group IIIA element is greater than or equal to 0.1 and less than 5.

3. The electrolyte according to claim 1, characterized in that, The chemical formula of the electrolyte includes A a M m Y y X x Wherein, A is the first cation element, M is the third cation element, Y is the second cation element, X is the anion element, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y<5, 0.1≤x≤30.

4. The electrolyte according to claim 1, characterized in that, The chemical formula of the electrolyte includes A a M m Y y D d Wherein, A is the first cation element, M is the third cation element, Y is the second cation element, D is the anion element, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y<5, 1≤d≤10.

5. The electrolyte according to claim 1, characterized in that, The chemical formula of the electrolyte includes A a M m Y y X x D d Wherein, A is the first cation element, M is the third cation element, Y is the second cation element, X includes at least one of the halogen elements, D includes at least one of the VIA group elements, 0.1≤a≤8, 0.1≤m≤8, 0.1≤y≤2, and m / y<5, 0.1≤x≤30, 1≤d≤10.

6. The electrolyte according to any one of claims 1 to 5, characterized in that, The electrolyte is in at least one of the following forms: emulsion, sol, gel, paste, ointment, clay, and wax.

7. The electrolyte according to claim 1, characterized in that, The Group VA elements include phosphorus; And / or, the Group IIIA elements include at least one of boron, aluminum, gallium and indium.

8. The electrolyte according to claim 1 or 7, characterized in that, The halogen elements include at least one of fluorine, chlorine, bromine, and iodine; And / or, the Group VIA elements include at least one of oxygen, sulfur and selenium.

9. The electrolyte according to claim 8, characterized in that, The electrolyte has the chemical formula A. a P m B y F x O d , where 0.1≤a≤6, 0.1≤m≤6, 0.1≤y≤2, 0.1≤x≤30, and 1≤d≤3.

10. The electrolyte according to claim 9, characterized in that, 0.1≤d / x≤10.

11. The electrolyte according to claim 1, characterized in that, The electrolyte has the chemical formula A. a P m Al y F x O d , where 0.1≤a≤3, 0.1≤m≤3, 0.1≤y≤2, 0.1≤x≤18, and 1≤d≤3.

12. The electrolyte according to claim 1, characterized in that, The electrolyte includes a solid electrolyte, and the average particle size of the solid electrolyte is 100 nm to 10000 nm.

13. The electrolyte according to claim 1, characterized in that, The electrolyte has an ionic conductivity of 0.001 mS / cm to 20 mS / cm at 25°C.

14. A method for preparing an electrolyte according to any one of claims 1 to 13, characterized in that, The preparation method includes: The first precursor and the second precursor are ground or sintered to obtain an electrolyte. The first precursor includes an inorganic polyanionic salt precursor, and the cationic element in the inorganic polyanionic salt precursor includes at least one of lithium, sodium, potassium, iron, cobalt and nickel. The polyanion in the inorganic polyanionic salt precursor includes at least one of group IIIA and group VA elements, and at least one of group VIA and halogen elements. The second precursor includes at least one of group IIIA, group VA, group VIA and halogen elements.

15. The preparation method according to claim 14, characterized in that, The molar ratio of the inorganic polyanionic salt precursor to the second precursor is greater than or equal to 0.1 and less than 5.

16. The preparation method according to claim 15, characterized in that, The electrolyte obtained by the grinding process has at least one of the following forms: emulsion, sol, gel, paste, ointment, clay, and wax.

17. The preparation method according to claim 14 or 15, characterized in that, The grinding process includes at least one of the following conditions: (Ⅰ) Rotation speed is 200 r / min to 1000 r / min; (II) The grinding process takes 0.5 h to 40 h; (III) The grinding process includes at least one of ball milling, planetary milling or sand milling.

18. The preparation method according to claim 14, characterized in that, The electrolyte obtained by the sintering treatment has at least one of the following forms: clay-like, wax-like, blocky, flake-like, and granular.

19. The preparation method according to claim 18, characterized in that, The sintering process includes at least one of the following conditions: (Ⅳ) The sintering temperature is 50℃~500℃; (V) The sintering time is 0.5h~10h; (VI) The heating and cooling rates of the sintering process are 1℃ / min to 10℃ / min; (VII) The sintering process includes solid-state sintering.

20. The preparation method according to claim 14, characterized in that, The inorganic polyanionic salt precursors include LiClO3, LiClO4, LiOH, Li2SO4, LiNH2, Li2NH, LiNO3, Li3PO4, Li4P2O7, Li2PO3F, LiPO2F2, LiPF6, Li2CO3, Li2C2O4, Li2SiO3, Li4SiO4, LiBH4, LiB3H8, and Li2B2H. 12 , Li2BH4NH2, LiBO2, Li3BO3, Li2B4O7, LiBF4, LiAlH4, Li3AlH6, Li3AlF6, LiAlF4, LiAlO2, Li2WO4, LiVO3, Li3VO4, LiV3O8, LiNbO3, LiTaO3, Li2TiF6, Li2TiO3, Li4Ti5O 12 At least one of Li2ZrO3 and LiMg(BH4)3.

21. The preparation method according to claim 14, characterized in that, The second precursor includes at least one of oxides, sulfides, and halides.

22. The preparation method according to claim 21, characterized in that, The oxides include Li₂O, Li₂O₂, Na₂O, Na₂O₂, K₂O, K₂O₂, KO₂, MgO, CaO, Sc₂O₃, Y₂O₃, La₂O₃, TiO₂, ZrO₂, HfO₂, V₂O₃, V₂O₅, Nb₂O₅, Ta₂O₅, Cr₂O₃, CrO₂, CrO₃, MoO₃, WO₂, WO₃, MnO, MnO₂, TcO₂, ReO₂, ReO₃, Re₂O₇, FeO, Fe₂O₃. O3, Fe3O4, CoO, Co2O3, Co3O4, Ni2O3, Cu2O, CuO, Ag2O, Au2O3, ZnO, B2O3, Al2O3, Ga2O3, In2O3, Tl2O3, S At least one of iO2, GeO, GeO2, SnO, SnO2, P2O3, P2O5, Sb2O3, Sb2O5, Bi2O3, SeO2, SeO3, TeO2, TeO3, I2O4, I2O5; And / or, the sulfides include Li₂S, Na₂S, K₂S, MgS, CaS, Sc₂S₃, Y₂S₃, La₂S₃, TiS₂, ZrS₂, HfS₂, V₂S₃, V₂S₅, Nb₂S₅, Ta₂S₅, Cr₂S₃, CrS₂, CrS₃, MoS₃, WS₂, WS₃, MnS, MnS₂, TcS₂, ReS₂, ReS₃, Re₂S₇, FeS, Fe₂S₃, Fe₃S₄. CoS, Co2S3, Co3S4, Ni2S3, Cu2S, CuS, Ag2S, Au2S3, ZnS, B2S3, Al2S3, Ga2S3, In2S3, Tl2S3, SiS2, G At least one of eS, GeS2, SnS, SnS2, P2S3, P2S5, Sb2S3, Sb2S5, Bi2S3, SeS2, SeS3, TeS2, TeS3, I2S4, and I2S5; And / or, the halides include LiX, NaX, KX, CsX, MgX2, CaX2, YX3, LaX3, TiX2, TiX4, ZrX2, ZrX4, HfX2, HfX4, VX2, VX5, NbX2, NbX5, TaX2, TaX5, CrX2, CrX3, MoX4, MoX6, WX4, WX5, WX6, MnX2, MnX3, Fe X2, FeX3, CoX2, NiX2, CuX, CuX2, AgX, AuX, AuX3, ZnX2, BX3, AlX3, GaX3, InX3, TlX, TlX3, GeX4, SnX2, SnX4, PX3, PX5, SbX3, BiX3, SeX4, BrF3, IF5, ICl, ICl3, IBr, where X includes at least one of the halogen elements.

23. The preparation method according to claim 14, characterized in that, The inorganic polyanionic salt includes at least one of LiPF6, LiBF4, LiBO2, and LiAlF4; And / or, the oxide includes at least one of P2O5 and B2O3; And / or, the sulfide includes at least one of P2S5 and B2S3.

24. The preparation method according to claim 14, characterized in that, The first precursor comprises an organic polyanionic salt.

25. The preparation method according to claim 24, characterized in that, The organic polyanionic salt includes at least one of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalateborate)borate, and lithium difluorooxalateborate.

26. An electrolyte membrane layer, characterized in that, The electrolyte membrane layer comprises the electrolyte of any one of claims 1 to 13 or the electrolyte prepared by the preparation method of any one of claims 14 to 25.

27. The electrolyte membrane layer according to claim 26, characterized in that, The electrolyte membrane layer further includes a carrier having a porous structure, and the electrolyte is located in the pores of the porous structure.

28. A single battery cell, characterized in that, The battery cell includes: A positive electrode sheet includes a positive current collector and a positive electrode film layer disposed on at least one side of the positive current collector; A negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one side of the negative current collector; An electrolyte membrane layer is located between the positive electrode and the negative electrode; Wherein, at least one of the positive electrode film layer, the negative electrode film layer and the electrolyte film layer comprises the electrolyte of any one of claims 1 to 13 or the electrolyte prepared by the preparation method of any one of claims 14 to 25.

29. The battery cell according to claim 28, characterized in that, The positive electrode film includes the electrolyte, the positive electrode active material, and the positive electrode conductive agent. Based on the mass of the positive electrode film, the mass content of the electrolyte is 2.5% to 30%, the mass content of the positive electrode active material is 50% to 95%, and the mass content of the positive electrode conductive agent is 2.5% to 20%.

30. The battery cell according to claim 28, characterized in that, The negative electrode film layer includes the electrolyte, the negative electrode active material, and the negative electrode conductive agent. Based on the total mass of the negative electrode film layer, the mass content of the electrolyte is 2.5% to 30%, the mass content of the negative electrode active material is 50% to 95%, and the mass content of the negative electrode conductive agent is 2.5% to 20%.

31. The battery cell according to claim 30, characterized in that, The negative electrode active material includes carbon-based negative electrode active materials and / or silicon-containing negative electrode active materials.

32. The battery cell according to claim 31, characterized in that, The carbon-based anode active material includes at least one of artificial graphite, natural graphite, graphitized carbon fiber, amorphous carbon, soft carbon, and hard carbon.

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