Quasi-solid-state electrolyte, method for producing the same, battery, and electric device

Abstract

The application discloses a kind of quasi-solid electrolyte and preparation method thereof, battery, electrical device, electrolyte salt is mixed with carbonate solvent, and preparation base electrolyte solution;Diluent and initiator are added to base electrolyte solution and are reacted, and quasi-solid electrolyte is prepared;The diluent includes ring-opening polymerizable cyclic monomer diluent, and the mass ratio of the diluent, the initiator and the base electrolyte solution is (30-70) : (0.1-0.5) : (30-70) in turn.The precursor solution containing local high concentration solvation structure is formed in the preparation process of quasi-solid electrolyte of the application, and quasi-solid electrolyte with low impedance, high ionic conductivity, excellent high rate performance and good safety performance is prepared using in-situ polymerization technology.The quasi-solid electrolyte prepared by the application is assembled into battery, with excellent charge-discharge performance, excellent cycle stability under high rate conditions, and low economic cost and high practicality.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to quasi-solid-state electrolytes and their preparation methods, batteries, and electrical devices. Background Technology

[0002] In recent years, with the rapid development of portable electronic devices and electric vehicles, batteries have become increasingly important energy storage systems. Electrolytes are an indispensable component of batteries, playing a crucial role in several ways, including: conducting ions (providing ion transport channels during charging and discharging, enabling ions to migrate between the positive and negative electrodes, thus transferring charge and completing the charging and discharging process); participating in electrochemical reactions (participating in a series of complex electrochemical reactions on the battery electrode surface, crucial for energy conversion and storage); and maintaining electrode potential (interacting with electrode materials to help maintain a stable electrode potential, ensuring normal battery operation). Currently, batteries primarily use liquid and solid electrolytes. However, the reactivity of metal ions with the electrolyte in liquid electrolytes is difficult to control, affecting charging and discharging speed and high-rate performance. Furthermore, the extensive use of organic solvents increases costs, and some organic solvents also cause environmental pollution. The inherent leakage and flammability risks of liquid electrolytes make them unsuitable for high-safety applications. Solid electrolytes have relatively high chemical and thermal stability, and there is no problem with electrolyte leakage, resulting in relatively high safety and reliability. However, the interface contact between solid electrolytes and electrodes is poor, leading to a significant increase in interface impedance, which affects the battery's electrical cycle performance and lifespan.

[0003] As a result, in recent years people have been increasing their requirements for high energy density and high safety energy storage devices, and electrolyte performance remains one of the core technical problems that energy storage batteries urgently need to solve. Summary of the Invention

[0004] Therefore, it is necessary to provide a quasi-solid electrolyte with low impedance, high ionic conductivity, excellent high-rate performance and excellent safety performance, as well as its preparation method, battery and electrical device.

[0005] In a first aspect, the present invention provides a method for preparing a quasi-solid-state electrolyte, comprising the following steps:

[0006] A basic electrolyte is prepared by mixing an electrolyte salt with a carbonate solvent.

[0007] A quasi-solid electrolyte is prepared by adding a diluent and an initiator to a base electrolyte and carrying out a polymerization reaction.

[0008] The diluent includes ring-opening polymerizable cyclic monomer diluents;

[0009] The mass ratio of the diluent, the initiator, and the base electrolyte is (30-70):(0.1-0.5):(30-70).

[0010] In some embodiments, the method for preparing the quasi-solid electrolyte further satisfies at least one of the following (1) to (7):

[0011] (1) The electrolyte salt includes sodium salt;

[0012] Optionally, the sodium salt includes a conductive sodium salt;

[0013] Optionally, the conductive sodium salt includes one or more of sodium difluoromethanesulfonylimide, sodium hexafluorophosphate, and sodium tetrafluoroborate;

[0014] (2) The electrolyte salt includes lithium salt;

[0015] Optionally, the lithium salt includes a conductive lithium salt;

[0016] Optionally, the conductive lithium salt includes one or more of lithium tetrafluoroborate, lithium hexafluorophosphate, and lithium difluorooxalate borate;

[0017] (3) The ring-opening polymerizable cyclic monomers include cyclic ether monomers;

[0018] Optionally, the cyclic ether monomer includes one or more of tetrahydrofuran, dioxolane, and dioxane;

[0019] (4) The carbonate solvents include one or more of fluoroethylene carbonate, ethylene carbonate, methyl ethyl carbonate and diethyl carbonate;

[0020] Optionally, the carbonate solvent includes two or more of fluoroethylene carbonate, ethylene carbonate, methyl ethyl carbonate, diethyl carbonate, and fluorohexene.

[0021] (5) The initiator includes a cationic initiator;

[0022] Optionally, the cationic initiator includes one or more of tris(pentafluorophenyl)borane, tris(hexafluoroisopropyl)borate, lithium hexafluorophosphate, and tin fluoride;

[0023] (6) The concentration of the electrolyte salt in the basic electrolyte solution is 1.5 mol / L-3 mol / L;

[0024] (7) The volume ratio of the carbonate solvent to the diluent is 1:(0.5-3).

[0025] In some embodiments, the carbonate solvent includes methyl ethyl carbonate and diethyl carbonate;

[0026] Optionally, the volume ratio of methyl ethyl carbonate to diethyl carbonate is (0.8-1.2):(0.8-1.2).

[0027] In some embodiments, the carbonate solvent includes ethyl methyl carbonate, diethyl carbonate, and fluoroethylene carbonate;

[0028] Optionally, the volume of the fluoroethylene carbonate is 1%-10% of the total volume of methyl ethyl carbonate and diethyl carbonate.

[0029] In some embodiments, the carbonate solvent includes methyl ethyl carbonate, diethyl carbonate, and ethylene carbonate;

[0030] Optionally, the volume ratio of methyl ethyl carbonate, diethyl carbonate and ethylene carbonate is (0.8-1.2):(0.8-1.2):(0.8-1.2).

[0031] In some embodiments, the carbonate solvent includes methyl ethyl carbonate, diethyl carbonate, ethylene carbonate, and fluoroethylene carbonate;

[0032] Optionally, the volume of the fluoroethylene carbonate is 1%-10% of the total volume of methyl ethyl carbonate, diethyl carbonate, and ethylene carbonate.

[0033] Secondly, the present invention provides a quasi-solid electrolyte, which is prepared by the preparation method of the quasi-solid electrolyte provided in the first aspect.

[0034] Thirdly, the present invention provides a battery comprising electrodes, a separator, and an electrolyte, wherein the quasi-solid electrolyte comprises a quasi-solid electrolyte prepared by the preparation method of the quasi-solid electrolyte provided in the first aspect, or a quasi-solid electrolyte provided in the second aspect.

[0035] In some embodiments, the battery further comprises the features shown in (1) and / or (2):

[0036] (1) The electrode includes a positive electrode and a negative electrode;

[0037] Optionally, the material of the positive electrode includes oxides containing transition metals and / or sodium vanadium phosphate;

[0038] Optionally, the negative electrode material includes metallic sodium and / or metallic lithium;

[0039] (2) The material of the diaphragm includes glass fiber and / or polypropylene;

[0040] Optionally, the diaphragm comprises at least one layer of diaphragm material.

[0041] Fourthly, an electrical device, characterized in that the electrical device comprises the battery and accessories provided in the third aspect.

[0042] Compared with traditional technologies, the technical solution of this application has the following beneficial effects:

[0043] This invention discloses a method for preparing a quasi-solid-state electrolyte. The method involves mixing a base electrolyte containing an electrolyte salt and a carbonate solvent with a diluent comprising a ring-opening polymerizable cyclic monomer to form a precursor solution containing locally high-concentration solvation structures. Under the initiation of an initiator, the quasi-solid-state electrolyte is then prepared. This method achieves in-situ polymerization, producing a quasi-solid-state electrolyte with low impedance, high ionic conductivity, excellent high-rate performance, and excellent safety performance. Compared to the safety issues associated with exposure in traditional liquid electrolytes or the interfacial contact problems of traditional solid electrolytes, this invention effectively overcomes the technical defects of traditional electrolytes. Batteries assembled with the quasi-solid-state electrolyte prepared by this invention exhibit excellent charge-discharge performance, superior cycle stability under high-rate conditions, and advantages such as low cost and high practicality. Attached Figure Description

[0044] Figure 1 The results of electrochemical impedance spectroscopy tests were performed on the battery assembled with the electrolyte corresponding to Example 1 at different temperatures.

[0045] Figure 2 The number of ions transferred during operation of the battery assembled with the electrolyte corresponding to Example 1.

[0046] Figure 3 The voltammetric curves are the electrochemical windows of the electrolytes in the batteries assembled with the electrolytes corresponding to Example 1, Comparative Example 1, and Comparative Example 2.

[0047] Figure 4 The long-term cycle performance of the batteries assembled with electrolytes corresponding to Example 1, Comparative Example 1, and Comparative Example 2.

[0048] Figure 5 The rate performance of the batteries assembled with electrolytes corresponding to Example 1, Comparative Example 1, and Comparative Example 2. Detailed Implementation

[0049] To facilitate understanding of the present invention, preferred embodiments are provided below to provide a more comprehensive description of the technical solutions of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a thorough and complete understanding of the disclosure of the present invention.

[0050] It should be noted that the experimental methods in the following embodiments of the present invention, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the embodiments are commercially available products.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0052] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this document; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, stating that a parameter is an integer ≥2 is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, stating that a parameter is an integer selected from "2-10" is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0053] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0054] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0055] Unless otherwise specified, the terms "comprising," "containing," and "including" as used in this application can be open-ended or closed-ended. In open-ended cases, for example, "comprising," "containing," and "including" can mean that other members, elements, or method steps not listed can also be included, or that only the listed members, elements, or method steps can be included.

[0056] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". Further, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0057] In this application, unless otherwise specified, A (e.g., B) means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0058] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0059] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0060] In this application, if the unit of a data range is only followed by the right endpoint, it means that the units of the left and right endpoints are the same.

[0061] Solid-state electrolytes (SSEs) are solid ion-conducting electrolytes and are characteristic components of solid-state batteries. They are further divided into all-solid-state electrolytes and quasi-solid-state electrolytes (QSSEs). All-solid-state electrolytes are also classified into inorganic solid electrolytes (ISEs), solid polymer electrolytes (SPEs), and composite polymer electrolytes (CPEs).

[0062] Quasi-solid electrolytes (QSSEs), also known as gel polymer electrolytes (GPEs), are independent membranes containing a certain amount of liquid components immobilized within a solid matrix.

[0063] Among mainstream battery technologies, liquid electrolytes and solid electrolytes are the main types. Liquid electrolytes contain a large amount of organic solvents, which can easily cause safety issues such as leakage, volatilization, and flammability. However, liquid electrolytes have high reactivity with electrode materials and a wide electrochemical window, enabling the battery to operate at higher voltages and improving energy density. But their high reactivity also brings corresponding negative effects, such as difficulty in control, numerous side reactions, and problems like coulombic efficiency decay and thermal runaway. Compared to liquid electrolytes, solid electrolytes have higher stability and safety performance, and do not exhibit liquid leakage. However, the interface problem between solid electrolytes and electrodes still lacks a good solution. Liquid electrolytes can effectively wet the electrode surface, while solid electrolytes struggle to cover and contact the electrode surface, resulting in more voids between the solid electrolyte and the electrode. This leads to higher interfacial impedance at the electrode surface, significantly limiting high-rate performance.

[0064] Based on the technical problems of the electrolytes mentioned above, the present invention provides a quasi-solid-state electrolyte with high safety, good energy storage effect and excellent electrocycle performance, as well as its preparation method, battery and electrical device.

[0065] In a first aspect, the present invention provides a method for preparing a quasi-solid-state electrolyte, comprising the following steps:

[0066] A basic electrolyte is prepared by mixing an electrolyte salt with a carbonate solvent.

[0067] A quasi-solid electrolyte is prepared by adding a diluent and an initiator to a base electrolyte and carrying out a polymerization reaction.

[0068] The diluent includes ring-opening polymerizable cyclic monomer diluents;

[0069] The mass ratio of the diluent, the initiator, and the base electrolyte is (30-70):(0.1-0.5):(30-70).

[0070] The quasi-solid electrolyte provided by this invention involves adding a carbonate solvent during its preparation process, which causes the electrolyte to contain a certain amount of liquid components fixed within a solid matrix. A high-concentration electrolyte is prepared by mixing the electrolyte salt with the carbonate solvent. This electrolyte is then mixed with a ring-opening polymerizable cyclic monomer diluent to produce a synergistic effect, forming a precursor solution containing a locally high-concentration solvation structure. Under the action of an initiator, the ring-opening polymerization of the ring-opening polymerizable cyclic monomer diluent is initiated, resulting in the quasi-solid electrolyte.

[0071] This invention involves mixing a base electrolyte containing electrolyte salts and carbonate solvents with a diluent to form a precursor solution with locally high-concentration solvation structures. Adjusting the mass ratio of the diluent, initiator, and base electrolyte to (30-70):(0.1-0.5):(30-70) results in an excellent solvation structure, enabling rapid ion conduction and stable interfacial film formation. This promotes rapid ion conduction and desolvation within the polymer framework, thereby improving interfacial compatibility and ion conductivity under high salt concentration conditions, and enhancing the stability and performance of the electrolyte. The quasi-solid-state electrolyte provided by this invention exhibits good contact with the electrode interface, significantly reducing interfacial porosity and impedance. It offers the technical advantages of low impedance, high ionic conductivity, excellent high-rate performance, and excellent safety performance, while also being both highly safe and cost-effective.

[0072] As a non-limiting example, the mass ratio of the diluent, the initiator, and the base electrolyte includes, but is not limited to, 30:0.1:70, 30:0.5:70, 40:0.1:60, 40:0.5:60, 50:0.1:50, 50:0.5:50, 60:0.1:40, 60:0.5:40, 70:0.1:30, 70:0.5:30, or any of the foregoing ranges and values ​​within those ranges.

[0073] Compared to off-site film-forming processes (such as solution casting and hot pressing) for preparing all-solid or quasi-solid electrolytes, which lead to electrode / electrolyte interface problems, high interfacial impedance, and severe limitations on high-rate performance, this invention utilizes in-situ polymerization technology to largely solve the aforementioned technical problems. It produces a quasi-solid electrolyte with low impedance, high ionic conductivity, excellent high-rate performance, and excellent safety performance.

[0074] As a non-limiting example, the quasi-solid electrolyte provided by the present invention includes a quasi-solid polymer electrolyte.

[0075] In some embodiments, the electrolyte salt includes a sodium salt and / or a lithium salt.

[0076] In some embodiments, the sodium salt includes a conductive sodium salt.

[0077] As a non-limiting example, in some embodiments, the conductive sodium salt includes one or more of sodium difluoromethanesulfonylimide, sodium hexafluorophosphate, and sodium tetrafluoroborate.

[0078] In some embodiments, the lithium salt includes a conductive lithium salt.

[0079] As a non-limiting example, in some embodiments, the conductive lithium salt includes one or more of lithium tetrafluoroborate, lithium hexafluorophosphate, and lithium difluorooxalate borate.

[0080] In recent years, with the rapid development of portable electronic devices and electric vehicles, lithium-ion batteries have faced challenges such as lithium resource scarcity and rising costs. Sodium resources, on the other hand, are abundant and widely distributed, making sodium batteries an ideal candidate technology for large-scale energy storage systems. Among these, metallic sodium anodes, with their high theoretical specific capacity of 1165 mAh / g (far exceeding the 300-350 mAh / g of hard carbon) and the lowest redox potential (-2.71 V vs. SHE), are considered key to breaking through the energy density bottleneck. However, the high reactivity of sodium metal with the electrolyte leads to uncontrolled dendrite growth and frequent interfacial side reactions, causing safety hazards such as coulombic efficiency decay and thermal runaway, seriously hindering its practical application.

[0081] Based on this, the preparation method of the quasi-solid electrolyte provided by the present invention particularly solves the key technical problems of resource shortage and battery performance in the battery field.

[0082] Furthermore, as a non-limiting example, in some embodiments, the conductive salt provided by the present invention uses a conductive sodium salt, which can better achieve mixing with carbonate solvents, thereby increasing the solubility of the conductive sodium salt in carbonate solvents and reducing its solubility in diluents. This enables the conductive sodium salt and carbonate solvents to form a high-concentration electrolyte, solving the core technical problem in the current sodium battery technology field.

[0083] As a non-limiting example, in some embodiments, the ring-opening polymerizable cyclic monomer includes cyclic ether monomers. The use of cyclic ether monomers in this invention better improves the compatibility of conductive salts, allowing the basic electrolyte containing electrolyte salts and carbonate solvents to produce a synergistic effect when mixed with the cyclic ether monomers, forming a precursor solution with locally high concentrations of solvated structures. This promotes uniform deposition of electrolyte salt ions and the formation of anion-derived stable SEI (solid electrolyte interface) layers. Studies have shown that compared to introducing fluoroether diluents (such as HFE, TTE), this invention achieves better technical effects. Furthermore, fluoroether diluents are expensive, and the fluorinated components have high environmental toxicity. The use of cyclic ether monomers in this invention offers better safety and economy.

[0084] The use of cyclic ether monomers in the preparation of the quasi-solid electrolyte of this invention has the following advantages: (1) Ring-opening polymerization can be achieved at room temperature, without the need for high-temperature ring-opening polymerization, and without the need for additional high-temperature resistant equipment and conditions, which has a great advantage of ease of operation in practical applications. (2) After the cyclic ether monomers of this invention are mixed with the basic electrolyte of this invention, a synergistic effect is produced, forming a precursor solution containing a locally high concentration of solvation structure, which can achieve the technical effect of this invention better than other types of diluent monomers. (3) Cyclic ether monomers have good ion transport capabilities. The oxygen atoms of cyclic ether monomers have lone pairs of electrons, which are easy to react with Li + / Na + The formation of coordination interactions effectively promotes the dissociation of conductive salts and improves ionic conductivity; furthermore, the polyether substances obtained by ring-opening polymerization of cyclic ether monomers possess strong electron-donating and chain segment mobility capabilities in their structural units, exhibiting excellent Li... + / Na + (4) Cyclic ether monomers have good electrochemical stability and can remain stable over a wide voltage range. They are not prone to redox reactions, which helps to improve the electrochemical window of the quasi-solid electrolyte of this invention, enabling the battery to work at higher voltages, thereby improving the energy density and performance of the battery. (5)

[0085] The polymers formed by the ring-opening and polymerization of cyclic ether monomers have good compatibility with electrode materials, can form a stable interface on the electrode surface, reduce side reactions between the electrode and the electrolyte, and improve the cycle stability and service life of the battery. (6) Cyclic ether monomers usually have relatively low cost and are widely available, which is of great significance for the large-scale production and application of the quasi-solid electrolyte provided by this invention.

[0086] The cyclic ether diluent provided by this invention needs to have extremely low solubility for electrolyte salts. This reduces the possibility of electrolyte salts agglomerating or crystallizing in the electrolyte, allowing more electrolyte salt ions to remain in a free state. This is beneficial for improving ionic conductivity and also prevents uneven deposition or crystallization of electrolyte salts on the electrode surface or inside the electrolyte during battery charging and discharging. This avoids problems such as changes in electrode surface morphology and damage to the electrolyte structure, helping to maintain the stability of the interface and the internal structure of the battery, and extending the cycle life of the battery. In particular, the cyclic ether diluent provided by this invention needs to have extremely low solubility for conductive sodium salts. As a non-limiting example, in some embodiments, the cyclic ether monomer includes one or more of tetrahydrofuran (THF), dioxolane, and dioxane. The dioxolane is selected from 1,3-dioxolane (DOL). The dioxane is selected from 1,4-dioxane (DOX) and 1,3-dioxane.

[0087] In some embodiments, the initiator includes a cationic initiator. On one hand, the cationic initiator can provide protons or accept electron pairs, effectively initiating the polymerization reaction of ring-opening polymerizable cyclic monomers in the quasi-solid electrolyte, especially cyclic ether monomers. The cationic initiator can promote their ring-opening polymerization, rapidly forming a polymer electrolyte network, which helps shorten battery fabrication time and improve production efficiency. On the other hand, the cationic initiator can promote the dissociation of electrolyte salts, especially conductive sodium salts, leaving more sodium ions in a free state, thereby improving ionic conductivity. Furthermore, the interaction between the cationic initiator and the polymer electrolyte may alter the electrolyte's microstructure, forming channels conducive to sodium ion transport, further enhancing ion migration efficiency. In addition, the polymerization reaction initiated by the cationic initiator affects parameters such as the polymer's molecular weight and degree of crosslinking. In particular, initiating the ring-opening and polymerization of cyclic ether monomers can optimize the electrolyte's mechanical properties, enabling it to better adapt to volume changes and mechanical stresses during battery charging and discharging, preventing problems such as electrolyte cracking and breakage, and ensuring long-term stable battery operation. As a non-limiting example, in some embodiments, the cationic initiator includes one or more of tris(pentafluorophenyl)borane (TPFPB), tris(hexafluoroisopropyl) borate (THB), lithium hexafluorophosphate, and tin fluoride, especially using tris(pentafluorophenyl)borane (TPFPB) and / or tris(hexafluoroisopropyl) borate (THB) as initiators to better achieve the technical effects of the present invention.

[0088] The use of carbonate solvents in this invention has the following advantages: firstly, they have a high dielectric constant, enabling effective dissociation of electrolyte salts, especially conductive sodium salts, thus allowing Na... + The high mobility in carbonate solvents improves the ionic conductivity of the quasi-solid-state electrolyte, thus contributing to enhanced charge / discharge and rate performance of sodium batteries. Furthermore, its high solubility for electrolyte salts further reduces their solubility in cyclic ether diluents, suppressing the insufficient ionic conductivity caused by dissolution and crystallization of electrolyte salts in cyclic ether diluents. As a non-limiting example, in some embodiments, the carbonate solvent includes one or more of fluoroethylene carbonate (FEC), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC). Compared to polycarbonate solvents, some of their strongly polar groups can exacerbate the decomposition of conductive salts, leading to decreased electrolyte stability. Therefore, the use of the carbonate solvent in this invention is necessary to achieve the technical effects of this invention.

[0089] In some embodiments, the carbonate solvent includes at least two of fluoroethylene carbonate, ethylene carbonate, methyl ethyl carbonate, and diethyl carbonate. Using a mixture of at least two of these carbonate solvents enables more efficient dissociation of the electrolyte salt, further improving the ionic conductivity of the quasi-solid-state electrolyte and contributing to enhanced battery charge / discharge performance and rate performance.

[0090] As a non-limiting example, in some embodiments, the carbonate solvent includes methyl ethyl carbonate and diethyl carbonate. Further, the volume ratio of methyl ethyl carbonate to diethyl carbonate is (0.8-1.2):(0.8-1.2), including but not limited to 0.8:1.2, 0.8:1, 1:0.8, 1:1, 1:1.2, 1.2:0.8, or any of the foregoing ranges and values ​​within those ranges. Within these ratio ranges, the technical effects of the present invention can be better achieved.

[0091] As a non-limiting example, in some embodiments, the carbonate solvent includes methyl ethyl carbonate, diethyl carbonate, and fluoroethylene carbonate. Further, the volume of the fluoroethylene carbonate is 1%-10% of the total volume of methyl ethyl carbonate and diethyl carbonate, including but not limited to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any of the foregoing ranges and values ​​within those ranges. Within this proportional range, the technical effects of the present invention can be better achieved.

[0092] As a non-limiting example, in some embodiments, the carbonate solvent includes methyl ethyl carbonate, diethyl carbonate, and ethylene carbonate. Further, the volume ratio of the methyl ethyl carbonate, diethyl carbonate, and ethylene carbonate is (0.8-1.2):(0.8-1.2):(0.8-1.2), including but not limited to 0.8:0.8:1.2, 0.8:1:1.2, 1:0.8:0.8, 1:0.8:1.2, 1:1:1, 1:1.2:0.8, 1.2:0.8:0.8, 1.2:1:0.8, 1.2:1.2:0.8, or any of the foregoing ranges and values ​​within those ranges. Within these ratio ranges, the technical effects of the present invention can be better achieved.

[0093] As a non-limiting example, in some embodiments, the carbonate solvent includes methyl ethyl carbonate, diethyl carbonate, ethylene carbonate, and fluoroethylene carbonate. Further, the volume of the fluoroethylene carbonate is 1%-10% of the total volume of methyl ethyl carbonate, diethyl carbonate, and ethylene carbonate, including but not limited to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any combination thereof and values ​​within that range. Within this proportional range, the technical effects of the present invention can be better achieved.

[0094] In the quasi-solid-state electrolyte prepared by this invention, the concentration of the electrolyte salt has a certain influence on the electrolyte and battery performance. In some embodiments, the concentration of the electrolyte salt in the base electrolyte is 1.5 mol / L-3 mol / L. Within this electrolyte salt concentration range, excellent ionic conductivity is observed, effectively improving the electrolyte's ability to conduct current. When the electrolyte salt concentration is below 1.5 mol / L, the ionic conductivity is insufficient, resulting in poor electrolyte current conduction. When the electrolyte salt concentration is above 3 mol / L, the interaction between ions is enhanced, potentially forming ion clusters, which conversely restricts ion migration, leading to a decrease in ionic conductivity. As a non-limiting example, the concentration of the electrolyte salt in the quasi-solid-state electrolyte prepared by this invention includes, but is not limited to, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.5 mol / L, 2.8 mol / L, 3 mol / L, or any range formed by both of the foregoing and values ​​within that range.

[0095] In the preparation process of the quasi-solid electrolyte provided by this invention, the electrolyte salt, carbonate solvent, and diluent work synergistically to form a precursor solution containing locally high concentrations of solvated structures. Therefore, the ratio of carbonate solvent to diluent has a significant impact on the solvated structure. In some embodiments, the volume ratio of the carbonate solvent to the diluent is 1:(0.5-3). As a non-limiting example, it includes, but is not limited to, 1:0.5, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, or any of the foregoing ranges and values ​​within those ranges.

[0096] In the preparation process of the quasi-solid electrolyte provided by this invention, the basic electrolyte containing electrolyte salt and carbonate solvent, along with the diluent, synergistically forms a precursor solution with locally high concentrations of solvated structures. Therefore, the proportions of electrolyte salt, carbonate solvent, and diluent all have a significant impact on the solvated structure. In some embodiments, the mass ratio of the diluent, the initiator, and the basic electrolyte is (50-70):(0.2-0.3):(30-50). As non-limiting examples, these include, but are not limited to, 50:0.2:50, 50:0.3:50, 55:0.2:45, 50:0.3:45, 60:0.2:40, 60:0.3:40, 70:0.2:30, 70:0.3:30, or any of the foregoing ranges and values ​​within those ranges.

[0097] The quasi-solid electrolyte provided by this invention achieves in-situ ring-opening polymerization at room temperature through a local high-concentration in-situ polymerization method, and completes the polymerization by standing for 1 to 3 days, thus preparing a quasi-solid electrolyte with high safety, good energy storage effect and excellent electrocycle performance.

[0098] Secondly, the present invention provides a quasi-solid-state electrolyte, which is prepared by the preparation method of the quasi-solid-state electrolyte provided in the first aspect. The electrolyte has an electrochemical window ≥4V, a sodium ion transport number of 0.4-0.9, and an ionic conductivity ≥0.5 mS / cm, exhibiting excellent energy storage performance, good electrocycling performance, and safety and reliability. In particular, in some embodiments, the electrolyte can also achieve an electrochemical window ≥4.5V, a sodium ion transport number of 0.6-0.9, and an ionic conductivity ≥0.6 mS / cm.

[0099] Thirdly, the present invention provides a battery comprising electrodes, a separator, and an electrolyte, wherein the quasi-solid electrolyte comprises a quasi-solid electrolyte prepared by the preparation method of the quasi-solid electrolyte provided in the first aspect, or a quasi-solid electrolyte provided in the second aspect.

[0100] In some embodiments, the electrode includes a positive electrode and a negative electrode.

[0101] In some embodiments, the positive electrode material includes oxides containing transition metals and / or sodium vanadium phosphate.

[0102] As a non-limiting example, the oxide containing the transition metal includes layered high-entropy oxides.

[0103] In some embodiments, the negative electrode material includes metallic sodium and / or metallic lithium.

[0104] In some embodiments, the membrane is made of glass fiber and / or polypropylene.

[0105] In some embodiments, the diaphragm comprises at least one layer of diaphragm material.

[0106] In some embodiments, the battery may further comprise one or more of a negative electrode shell, a spring sheet, a gasket, and a positive electrode shell.

[0107] As a non-limiting example, in some embodiments, the battery comprises: stacked sequentially in the order of negative electrode shell, spring sheet, gasket, negative electrode sheet, electrolyte, separator, electrolyte, positive electrode sheet, and positive electrode shell.

[0108] In some embodiments, the battery is encapsulated in an argon atmosphere.

[0109] As a non-limiting example, in some embodiments, the battery includes, but is not limited to, sodium batteries and lithium batteries.

[0110] As a non-limiting example, in some embodiments, the sodium and lithium batteries are in the form of, but are not limited to, button batteries.

[0111] Fourthly, an electrical device, characterized in that the electrical device comprises the battery and accessories provided in the third aspect.

[0112] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0113] The raw materials and reagents involved in the following specific embodiments can be obtained commercially or prepared by those skilled in the art using known methods.

[0114] The model specifications of some of the raw materials and reagents involved in this invention are as follows:

[0115] Sodium difluoromethanesulfonyl imide (NaFSI, CAS No.: 100669-96-3); Sodium hexafluorophosphate (CAS No.: 21324-39-0); Sodium tetrafluoroborate (CAS No.: 13755-29-8); Fluorinated vinyl carbonate (FEC, CAS No.: 114435-02-8), vinyl carbonate (EC, CAS No.: 96-49-1), ethyl methyl carbonate (EMC, CAS No.: 623-53-0), diethyl carbonate Ester (DEC, CAS No.: 105-58-8); Tetrahydrofuran (THF, CAS No.: 109-99-9), 1,3-dioxolane (DOL, CAS No.: 646-06-0), 1,4-dioxane (DOX, CAS No.: 123-91-1); Tris(pentafluorophenyl)borane (TPFPB, CAS No.: 1109-15-5), Tris(hexafluoroisopropyl)borate (THB, CAS No.: 6919-80-8).

[0116] Example 1

[0117] The preparation method of the quasi-solid electrolyte in this embodiment is as follows:

[0118] Under an argon atmosphere, sodium difluoromethanesulfonylimide (NaFSI) was first dissolved in a mixed solvent (EMC: DEC: EC = 1:1:1 volume ratio, Vol% + 5% FEC) to form a mixed solution with a NaFSI concentration of 3 mol / L. 1,3-dioxolane (DOL) was added as a cyclic ether diluent monomer, and tris(pentafluorophenyl)borane (TPFPB) was added as an initiator. The mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte was 70:0.3:30. The solution was magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0119] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell, and then encapsulated. The entire assembly process was completed in an argon-filled glove box. After encapsulation, the batteries were placed at room temperature for 3 days to allow the electrolyte to complete the initiation of polymerization, resulting in a button sodium battery.

[0120] Example 2

[0121] The preparation method of the quasi-solid electrolyte in this embodiment is as follows:

[0122] Under an argon atmosphere, sodium hexafluorophosphate was first dissolved in a mixed solvent (DEC: EC = 1:1 volume ratio) to form a mixed solution with a sodium hexafluorophosphate concentration of 2.5 mol / L. Tetrahydrofuran (THF) was added as a cyclic ether diluent monomer, and tris(pentafluorophenyl)borane (TPFPB) was added as an initiator. The mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte was 45:0.2:55. The solution was magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0123] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell, and then encapsulated. The entire assembly process was completed in an argon-filled glove box. After encapsulation, the batteries were placed at room temperature for 3 days to allow the electrolyte to complete the initiation of polymerization, resulting in a button sodium battery.

[0124] Example 3

[0125] The preparation method of the quasi-solid electrolyte in this embodiment is as follows:

[0126] Under an argon atmosphere, sodium hexafluorophosphate was first dissolved in a mixed solvent (EMC: DEC: EC = 1:1:1 volume ratio) to form a mixed solution with a sodium hexafluorophosphate concentration of 3 mol / L. 1,4-dioxane (DOX) was added as a cyclic ether diluent monomer, and tri(hexafluoroisopropyl) borate (THB) was added as an initiator. The mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte was 55:0.2:45. The solution was magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0127] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell, and then encapsulated. The entire assembly process was completed in an argon-filled glove box. After encapsulation, the batteries were placed at room temperature for 3 days to allow the electrolyte to complete the initiation of polymerization, resulting in a button sodium battery.

[0128] Example 4

[0129] The preparation method of the quasi-solid electrolyte in this embodiment is as follows:

[0130] Under an argon atmosphere, sodium difluoromethanesulfonylimide (NaFSI) and sodium tetrafluoroborate were first dissolved in a mixed solvent (EMC: DEC = 1:1 volume ratio) to form a mixed solution with NaFSI concentration of 2 mol / L and sodium tetrafluoroborate concentration of 0.3 mol / L. 1,3-dioxolane (DOL) was added as a cyclic ether diluent monomer and tris(pentafluorophenyl)borane (TPFPB) as an initiator. The mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte was 60:0.3:40. The solution was magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0131] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell, and then encapsulated. The entire assembly process was completed in an argon-filled glove box. After encapsulation, the batteries were placed at room temperature for 3 days to allow the electrolyte to complete the initiation of polymerization, resulting in a button sodium battery.

[0132] Example 5

[0133] The preparation method of the quasi-solid electrolyte in this embodiment is as follows:

[0134] Under an argon atmosphere, sodium hexafluorophosphate and sodium tetrafluoroborate were first dissolved in a mixed solvent (EMC: DEC: EC = 1:1:1 volume ratio) to form a mixed solution with a sodium hexafluorophosphate concentration of 1.5 mol / L and a sodium tetrafluoroborate concentration of 0.3 mol / L. 1,3-dioxolane (DOL) was added as a cyclic ether diluent monomer, and tris(hexafluoroisopropyl) borate (THB) was added as an initiator. The mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte was 60:0.3:40. The solution was magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0135] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell, and then encapsulated. The entire assembly process was completed in an argon-filled glove box. After encapsulation, the batteries were placed at room temperature for 3 days to allow the electrolyte to complete the initiation of polymerization, resulting in a button sodium battery.

[0136] Example 6

[0137] The preparation method of the quasi-solid electrolyte in this embodiment is as follows:

[0138] Under an argon atmosphere, sodium difluoromethanesulfonylimide (NaFSI) was first dissolved in a mixed solvent (PFH : EC = 1:1 volume ratio) to form a mixed solution with a NaFSI concentration of 2.5 mol / L. 1,4-dioxane (DOX) was added as a cyclic ether diluent monomer and tris(pentafluorophenyl)borane (TPFPB) was added as an initiator. The mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte was 40:0.2:60. The solution was magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0139] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell, and then encapsulated. The entire assembly process was completed in an argon-filled glove box. After encapsulation, the batteries were placed at room temperature for 3 days to allow the electrolyte to complete the initiation of polymerization, resulting in a button sodium battery.

[0140] Example 7

[0141] The preparation method of the quasi-solid electrolyte in this embodiment is as follows:

[0142] Under an argon atmosphere, sodium hexafluorophosphate was first dissolved in a mixed solvent (FEC: EC = 1:1 volume ratio) to form a mixed solution with a sodium hexafluorophosphate concentration of 1.5 mol / L. Tetrahydrofuran (THF) was added as a cyclic ether diluent monomer, and tris(pentafluorophenyl)borane (TPFPB) was added as an initiator. The mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte was 30:0.2:70. The solution was magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0143] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell, and then encapsulated. The entire assembly process was completed in an argon-filled glove box. After encapsulation, the batteries were placed at room temperature for 3 days to allow the electrolyte to complete the initiation of polymerization, resulting in a button sodium battery.

[0144] Example 8

[0145] The difference from Example 1 is that the initiator is different. In this example, an equal amount of lithium hexafluorophosphate is used as the initiator, while the other components, contents, and preparation methods are the same as in Example 1.

[0146] Example 9

[0147] The difference from Example 1 is that the initiator is different. In this example, an equal amount of tin fluoride is used as the initiator, while the other components, contents, and preparation methods are the same as in Example 1.

[0148] Comparative Example 1

[0149] The preparation method of this comparative quasi-solid electrolyte is as follows:

[0150] Under an argon atmosphere, sodium difluoromethanesulfonylimide (NaFSI) was first dissolved in a mixed solvent (DMC: DEC: EC = 1:1:1 volume ratio Vol% + 5% FEC) to form a mixed solution with a NaFSI concentration of 3 mol / L. The solution was then magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0151] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell. The entire assembly process was completed in a glove box filled with argon gas. After sealing, the batteries were placed at room temperature for 3 days to obtain button sodium batteries.

[0152] Comparative Example 2

[0153] The preparation method of this comparative quasi-solid electrolyte is as follows:

[0154] Under an argon atmosphere, sodium difluoromethanesulfonylimide (NaFSI) was first dissolved in a mixed solvent (FEC: EC = 1:1 volume ratio) to form a mixed solution with a NaFSI concentration of 3 mol / L. 1,3-dioxolane (DOL) was added as a cyclic ether diluent monomer, wherein the mass ratio of the cyclic ether diluent monomer to the basic electrolyte was 30:70. The solution was magnetically stirred to form a transparent and homogeneous solution as a quasi-solid electrolyte precursor.

[0155] Sodium metal sheet was selected as the negative electrode of the battery, sodium vanadium phosphate was selected as the positive electrode, and commercially available GF / D glass fiber separator was used. The quasi-solid electrolyte precursor prepared above was used as the electrolyte of the sodium battery. The batteries were stacked in the following order: negative electrode shell - spring sheet - gasket - negative electrode sheet - electrolyte - separator - electrolyte - positive electrode sheet - positive electrode shell. The entire assembly process was completed in a glove box filled with argon gas. After sealing, the batteries were placed at room temperature for 3 days to obtain button sodium batteries.

[0156] Comparative Example 3

[0157] The difference from Example 1 is that the mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte is different. In this comparative example, the mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte is 75:0.3:25. The other components, contents, and preparation methods are the same as in Example 1.

[0158] Comparative Example 4

[0159] The difference from Example 1 is that the mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte is different. In this comparative example, the mass ratio of the cyclic ether diluent monomer, initiator, and basic electrolyte is 25:0.3:75. The other components, contents, and preparation methods are the same as in Example 1.

[0160] Experimental Example 1

[0161] The batteries prepared in Examples 1-9 and Comparative Examples 1-4 were subjected to relevant performance tests, and the specific test methods are as follows:

[0162] (1) The electrochemical impedance of the battery was tested using an Autolab electrochemical workstation.

[0163] (2) A polarization voltage of 10 mV was applied to the battery using an Autolab electrochemical workstation. The initial current and steady-state current were measured using the chronoamperometry method. The initial current (I0) and steady-state current (I2) were recorded using the chronoamperometry method. S ), and polarization voltage (ΔV = 10mV). Sodium ion transport number (t+ The result is calculated using formula (I). Where R0 and R... S These are the electrochemical impedances of the symmetrical cells before and after polarization.

[0164] (I)

[0165] (3) Set the scan rate to 5 mV s using the Autolab electrochemical workstation. −1 The scanning range is 1V~6V, and the voltammetric curves of the electrochemical window of the electrolyte are measured by linear sweep voltammetry (LSV).

[0166] (4) Battery cycle performance test: The electrochemical performance of the assembled battery was tested using the Wuhan Land-CT2001A battery testing system. Constant current density charge-discharge tests were conducted within the set voltage window to study the battery cycle performance.

[0167] (5) Rate performance testing of the battery: The electrochemical performance of the assembled battery was tested using the Wuhan Land-CT2001A battery testing system. Charge and discharge tests were conducted within the set voltage window to study the battery's charge and discharge specific capacity, cycle performance, coulombic efficiency, rate performance, etc. at different current densities.

[0168] (6) Long-term cycle stability test of the battery at a high rate of 10C: The electrochemical performance of the assembled battery was tested using the Wuhan Land-CT2001A battery testing system. Charge and discharge tests were conducted within the set voltage window to study the charge and discharge specific capacity and cycle performance of the battery at a high rate of 10C.

[0169] The battery performance results obtained using the above testing method are shown in Table 1 and appendix. Figure 1 To be continued Figure 5 As shown:

[0170] Table 1: Battery performance test results of quasi-solid-state electrolyte assembly

[0171]

[0172] The introduction of ring-opening polymerizable cyclic monomer diluents and the locally high-concentration solvation structure constructed together with carbonate-based electrolyte salts effectively improved the cycle performance of the electrolyte under rapid charge and discharge. At the same time, in-situ cationic ring-opening polymerization improved the electrochemical window and chemical stability of the electrolyte. Meanwhile, the locally solvation structure in the polymer ensured that it still had high ionic conductivity after polymerization. In comparison, the non-polymerized system has a narrower electrochemical window, non-specific initiators lead to side reactions causing battery capacity loss, and the addition of non-specific proportions of diluents can cause sodium salt precipitation and battery failure.

[0173] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0174] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a quasi-solid-state electrolyte, characterized in that, Includes the following steps: A basic electrolyte is prepared by mixing an electrolyte salt with a carbonate solvent. A quasi-solid electrolyte is prepared by adding a diluent and an initiator to the basic electrolyte and carrying out a polymerization reaction. The electrolyte salt is a sodium salt; The diluent comprises a ring-opening polymerizable cyclic monomer; the ring-opening polymerizable cyclic monomer comprises a cyclic ether monomer; The carbonate solvents include methyl ethyl carbonate, diethyl carbonate, ethylene carbonate, and fluoroethylene carbonate; the volume of the fluoroethylene carbonate is 1%-10% of the total volume of methyl ethyl carbonate, diethyl carbonate, and ethylene carbonate. The initiator includes a cationic initiator, which includes one or more of tris(pentafluorophenyl)borane and tris(hexafluoroisopropyl) borate; The mass ratio of the diluent, the initiator, and the base electrolyte is (30-70):(0.1-0.5):(30-70).

2. The method for preparing the quasi-solid electrolyte according to claim 1, characterized in that, The sodium salt includes a conductive sodium salt.

3. The method for preparing the quasi-solid electrolyte according to claim 2, characterized in that, The conductive sodium salt includes one or more of sodium difluoromethanesulfonylimide, sodium hexafluorophosphate, and sodium tetrafluoroborate.

4. The method for preparing the quasi-solid electrolyte according to claim 1, characterized in that, The cyclic ether monomers include one or more of tetrahydrofuran, dioxolane, and dioxane.

5. The method for preparing the quasi-solid electrolyte according to claim 1, characterized in that, The concentration of the electrolyte salt in the basic electrolyte is 1.5 mol / L-3 mol / L; and / or the volume ratio of the carbonate solvent to the diluent is 1:(0.5-3).

6. The method for preparing the quasi-solid electrolyte according to claim 1, characterized in that, The volume ratio of the methyl ethyl carbonate, the diethyl carbonate, and the ethylene carbonate is (0.8-1.2):(0.8-1.2):(0.8-1.2).

7. A quasi-solid-state electrolyte, characterized in that, The quasi-solid electrolyte is prepared by the method for preparing quasi-solid electrolyte according to any one of claims 1 to 6.

8. A battery, characterized in that, The battery comprises electrodes, a separator, and an electrolyte, wherein the electrolyte comprises a quasi-solid-state electrolyte prepared by the preparation method according to any one of claims 1 to 6, or a quasi-solid-state electrolyte according to claim 7.

9. The battery according to claim 8, characterized in that, The battery also has the following features as shown in (1) and / or (2): (1) The electrode includes a positive electrode and a negative electrode; (2) The material of the diaphragm includes one or more of glass fiber and polypropylene.

10. The battery according to claim 9, characterized in that, The positive electrode material includes one or more of transition metal oxides and sodium vanadium phosphate; and / or, the negative electrode material includes metallic sodium; and / or, the separator includes at least one layer of separator material.

11. An electrical device, characterized in that, The electrical device comprises the battery and accessories as described in any one of claims 8 to 10.

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