Electrolyte and preparation method and application thereof

Abstract

The invention provides an electrolyte as well as a preparation method and application thereof, and relates to the technical field of secondary batteries. Specifically, the electrolyte of the present invention includes an electron acceptor polymer and an electron donor polymer having a specific molecular structure. The electrolyte disclosed by the invention has a wide-temperature-range phase change temperature, a charge transfer effect can be generated between the electron donor and the electron acceptor to form a charge transfer complex, and the charge transfer effect has high reversibility and can be regulated and controlled through temperature, so that the electrolyte shows a temperature sensitive characteristic. When the electrolyte is used for preparing a secondary battery, good electrolyte ionic conductivity, low-temperature conductivity, high-temperature safety and cost effectiveness are shown, and the electrolyte has a good application prospect.

Description

Technical Field

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

[0002] Lithium-ion batteries, as a core technology of modern energy storage, dominate the electric vehicle, portable electronic device, and energy storage system markets due to their high energy density and long cycle life. Liquid organic solvents are flammable and explosive, and under high temperatures, overcharging, or mechanical damage, they can easily trigger a chain reaction of exothermic reactions, leading to battery fires or explosions. Furthermore, in fast charging or low-temperature environments, lithium dendrites may pierce the separator, causing short circuits and further exacerbating the risk of thermal runaway. To overcome the safety bottlenecks of liquid systems, solid-state batteries are considered the next-generation solution; they use non-flammable solid electrolytes (polymers / oxides / sulfides), which theoretically can suppress dendrite formation and improve energy density. However, solid-state batteries face the challenge of significantly reduced ionic conductivity at low temperatures, which is one of the key bottlenecks restricting their application in low-temperature scenarios. For example, the ionic conductivity of sulfide solid electrolytes at -20℃ is only 0.1~0.2 mS / cm.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] The primary objective of this invention is to provide an electrolyte that addresses the technical deficiency of simultaneously achieving high-temperature safety and low-temperature ionic conductivity. The electrolyte of this invention is liquid at room temperature and transforms into a solid state at a certain temperature, thus combining the advantages of both liquid and solid electrolytes.

[0005] The second objective of this invention is to provide a method for preparing the electrolyte, which is simple, easy to implement, and readily mass-produced.

[0006] A third objective of this invention is to provide a secondary battery.

[0007] The fourth objective of this invention is to provide an electrical device.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: An electrolyte comprising an electron acceptor polymer and an electron donor polymer; The electron acceptor polymer includes at least one of the following polymers (a) to (c): (a); (b); (c); The electron donor polymer includes the following polymer (d): (d); Furthermore, in polymers (a) to (c), n is independently selected from 100 to 1000, and in polymer (d), m is selected from 1 to 10.

[0009] In one embodiment, the content of the electron acceptor polymer in the electrolyte is 3 wt.% to 12 wt.%, and the content of the electron donor polymer is 3 wt.% to 12 wt.%.

[0010] In one embodiment, the electrolyte further includes an organic solvent; The organic solvent includes at least one of carbonates or ethers, and / or, in the electrolyte, the content of the organic solvent is 65 wt.% to 80 wt.%.

[0011] In one embodiment, the electrolyte further includes a lithium salt; The lithium salt includes at least one of LiPF6, LiBF4, LiFSI, LiTFSI, LiClO4, LiAsF6, LiBOB, and LiDFOB, and / or, in the electrolyte, the content of the lithium salt is 8 wt.% to 18 wt.%.

[0012] In one embodiment, the electrolyte further includes additives; The additive includes at least one of 1,2-dimethoxybenzene, 2,5-oxazolidinone, N,N-dimethyltrifluoroacetamide, 2,3,5,6-tetrafluorop-diazabenzene, and N,N-diethyltrimethylsilylamine, and / or, in the electrolyte, the content of the additive is 2 wt.% to 4 wt.%.

[0013] In one embodiment, the phase transition temperature of the electrolyte is 20°C to 70°C.

[0014] A method for preparing the electrolyte includes: thoroughly mixing the components of the electrolyte to obtain the electrolyte.

[0015] A secondary battery comprising the electrolyte.

[0016] In one embodiment, the secondary battery is a lithium-ion battery; The positive electrode of the lithium-ion battery includes one of lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, or ternary materials, and the negative electrode includes one of graphite, silicon, silicon-carbon composite material, or metallic lithium.

[0017] An electrical device includes the aforementioned secondary battery.

[0018] This invention provides a wide-temperature-range phase-change electrolyte in which charge transfer occurs between the electron donor and electron acceptor, forming a charge-transfer complex. This charge transfer is highly reversible and can be controlled by temperature, making the electrolyte exhibit temperature-sensitive properties. Specifically, the electrolyte is liquid at lower ambient temperatures. As the temperature increases, the charge transfer disappears, the electron donor and acceptor polymer becomes insoluble in the electrolyte, precipitates from the solution, and encapsulates other components of the electrolyte, resulting in a solid electrolyte with high-temperature safety and stability.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) High conductivity at low temperature: By adjusting the content of electron donor / acceptor polymer, lithium salt content, and the type and content of additives, the electrolyte of the present invention can achieve a high ionic conductivity at low temperature, which is 5 to 10 times that of conventional sulfide solid electrolytes.

[0020] (2) High temperature safety: When the lithium battery using the electrolyte of the present invention is in the normal operating temperature range of 20°C to 30°C, the electrolyte is in a liquid state; when the battery temperature rises, the electrolyte undergoes a phase change and becomes solid, thus improving high temperature safety.

[0021] (3) Low cost: Existing temperature phase change electrolytes usually use ionic liquids as carriers, which are expensive. For example, the cost of imidazole ionic liquids is as high as 500~1500 yuan / kg. In contrast, the present invention uses low-cost organic solvents to achieve a wide temperature range phase change of electrolytes from 20℃ to 70℃. Compared with ionic liquids, the present invention has a much lower cost while maintaining similar performance. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A comparison chart of discharge capacity performance in the test examples of this invention is provided. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] A first aspect of the present invention is to provide an electrolyte, which mainly comprises an electron acceptor polymer and an electron donor polymer.

[0026] The electron acceptor polymer of the present invention comprises at least one of the following polymers (a) to (c): (a); (b); (c); The electron donor polymer of the present invention comprises the following polymer (d): (d); Furthermore, in polymers (a) to (c), n is independently selected from 100 to 1000, and in polymer (d), m is selected from 1 to 10.

[0027] This invention provides a temperature-sensitive electrolyte with a wide temperature range phase transition temperature. When the electrolyte of this invention is used, the battery can achieve high ionic conductivity at low temperatures while maintaining high-temperature safety.

[0028] This invention introduces two types of polymers into an electrolyte: one acts as an electron donor, and the other as an electron acceptor. These polymers can interact via charge transfer, forming a charge-transfer complex (CTC). This charge transfer interaction is highly reversible and can be controlled by temperature, giving the electrolyte temperature-sensitive properties. At low temperatures, the electrolyte is liquid; as the temperature rises, the charge transfer interaction disappears, the polymers become insoluble in the electrolyte, precipitate out of the solution, and encapsulate other electrolyte components, resulting in a solid electrolyte with high-temperature safety and stability.

[0029] As an optional implementation, the n value in polymers (a) to (c) can be selected independently, including but not limited to any one or any two of the following numerical ranges: 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, and 1000.

[0030] As an optional implementation, in the polymer (d), m includes, but is not limited to, any one or any two of the following numerical ranges: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

[0031] In a preferred embodiment, the content of the electron acceptor polymer in the electrolyte is 3 wt.% to 12 wt.%, including but not limited to any one or any two of the following values: 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 (wt.%).

[0032] In a preferred embodiment, the content of the electron donor polymer in the electrolyte is 3 wt.% to 12 wt.%, including but not limited to any one or any two of the following values: 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 (wt.%).

[0033] In a preferred embodiment, the electron acceptor polymer and the electron donor polymer are present in the same amount.

[0034] In a preferred embodiment, the electrolyte further includes an organic solvent, which includes at least one of carbonate compounds or ether compounds; in some optional embodiments, the carbonate compounds include, but are not limited to, at least one of ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), or propylene carbonate (PC), and the ether compounds include, but are not limited to, at least one of dimethoxymethane, 1,2-dimethoxyethane, 1,2-dimethoxypropane, and diethylene glycol dimethyl ether.

[0035] In a more preferred embodiment, the content of the organic solvent in the electrolyte is 65 wt.% to 80 wt.%, including but not limited to any one or any two of 65, 68, 70, 72, 75, 78, 80, 82, and 85 (wt.%).

[0036] In a preferred embodiment, the electrolyte further includes a lithium salt, which includes at least one of LiPF6, LiBF4, LiFSI, LiTFSI, LiClO4, LiAsF6, LiBOB, and LiDFOB.

[0037] In a more preferred embodiment, the lithium salt content in the electrolyte is 8 wt.% to 18 wt.%, including but not limited to any one or any two of the following values: 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18 (wt.%).

[0038] In a preferred embodiment, the electrolyte further includes an additive; the additive includes at least one selected from 1,2-dimethoxybenzene, 2,5-oxazolidinone, N,N-dimethyltrifluoroacetamide, 2,3,5,6-tetrafluorop-diazabenzene, and N,N-diethyltrimethylsilylamine.

[0039] In a more preferred embodiment, the content of the additive in the electrolyte is 2wt.% to 4wt.%, including but not limited to any one or any two of the following: 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, and 4 (wt.%).

[0040] In a preferred embodiment, the phase transition temperature of the electrolyte is 20°C to 70°C. It is worth noting that the phase transition temperature refers to the temperature at which the electrolyte changes from a liquid to a solid state. In this invention, the phase transition temperature is affected by various factors such as component composition and weight ratio, and those skilled in the art can customize the specific phase transition temperature of the electrolyte by adjusting the aforementioned preferred features. Furthermore, the electrolyte material of this invention can achieve phase transition over a wide temperature range. By changing the amount and ratio of electron donors and / or acceptors, the phase transition temperature can be controlled. Specifically, when there are more electron donors, the competition among electron donors is enhanced, weakening the charge transfer between electron donors and acceptors, thus lowering the phase transition temperature.

[0041] In a preferred embodiment, the synthetic route of the electron acceptor polymer includes: mixing a first monomer, a second monomer, one of triethylamine or pyridine, and a reaction solvent, and reacting them under stirring at 20°C to 30°C for 3 to 5 hours; after the reaction is completed, removing excess first monomer by vacuum distillation, and then obtaining the precursor of the electron acceptor polymer by washing with water, extraction, and drying. Wherein, the first monomer is When the electron acceptor polymer is polymer (a), the second monomer is... When the electron acceptor polymer is polymer (b), the second monomer is When the electron acceptor polymer is polymer (c), the second monomer is... ; Furthermore, when the electron acceptor polymer is polymer (a), the precursor is... When the electron acceptor polymer is polymer (b), the precursor is... When the electron acceptor polymer is polymer (c), the precursor is... ; As an optional implementation, the extraction uses diethyl ether as the extractant, and the diethyl ether phase is separated after extraction for subsequent drying; the drying is carried out under vacuum at a temperature of 60℃~80℃ for 4h~6h.

[0042] In a more preferred embodiment, the molar ratio of the first monomer to the second monomer is 3:1, and the reaction solvent is DMF and DMSO.

[0043] Further, for the above synthetic route, the preparation of the electron acceptor polymer from the precursor includes the following steps: stirring the precursor, initiator, and second reaction solvent at 60℃~100℃ for 1h~3h, allowing the reaction system to precipitate and separate in a poor solvent after the reaction is completed, and then drying to obtain the electron acceptor polymer.

[0044] As an optional implementation, the drying is carried out under vacuum at a temperature of 80℃~100℃ for a duration of 6h~10h.

[0045] In a more preferred embodiment, the molar ratio of the precursor to the initiator is 100:1 to 200:1, the molar ratio of the precursor to the second reaction solvent is 1:10 to 1:5, the initiator includes at least one of azobisisobutyronitrile (AIBN), azobisisoheptanenitrile (ABVN), and benzoyl peroxide (BPO), the second reaction solvent includes at least one of toluene or ethyl acetate, and the undesirable solvent includes methanol.

[0046] Furthermore, when the electron donor polymer is polymer (d), it can be purchased from commercial channels or prepared by conventional synthetic routes in the art, and is not strictly limited in this invention.

[0047] A second aspect of the present invention is to provide a method for preparing an electrolyte as described in the first aspect, which mainly includes the following steps: thoroughly mixing the components of the electrolyte to obtain the electrolyte.

[0048] In a preferred embodiment, the electrolyte is obtained by thoroughly mixing the electron acceptor polymer, the electron donor polymer, the lithium salt, the additive, and the organic solvent.

[0049] As an optional implementation method, the thorough mixing can be assisted by means of oscillation, stirring, shaking, centrifugation, ultrasound, heating, etc., which helps to accelerate dispersion and obtain a relatively uniform dispersion system.

[0050] A third aspect of the present invention is to provide a secondary battery comprising an electrolyte as described in the second aspect.

[0051] In a preferred embodiment, the secondary battery is a lithium-ion battery.

[0052] In a more preferred embodiment, the positive electrode of the lithium-ion battery comprises one of lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, or a ternary material, and the negative electrode comprises one of graphite, silicon, silicon-carbon composite material, or metallic lithium. In some optional embodiments, the separator of the lithium-ion battery comprises one of polyethylene, polypropylene, polyimide, polyamide, polyvinylidene fluoride, or polytetrafluoroethylene.

[0053] A fourth aspect of the present invention is to provide an electrical device comprising a secondary battery as described in the third aspect.

[0054] It is understood that the electrical equipment can be any kind of equipment or device that relies on electrical energy to work or operate, including but not limited to new energy vehicles, building electrical equipment, industrial electrical appliances, household and agricultural electrical appliances, etc.; when the secondary battery is included, any electrical equipment equipped with the secondary battery can be an embodiment of the present invention.

[0055] Example 1 S1, Synthesis of polymer (b): The first monomer, the second monomer, triethylamine, and solvent (DMF) were added to a three-necked flask equipped with a condenser and purged with nitrogen. The molar ratio of the first monomer to the second monomer was 3:1. The reaction system was stirred at 25°C for 4 hours. After the reaction was completed, excess first monomer was removed by vacuum distillation. The resulting reaction system was washed with water and extracted with diethyl ether. The diethyl ether phase was dried under vacuum at 70°C for 5 hours to obtain the precursor. The first monomer is: The second monomer is: The precursor is: ; The aforementioned precursor, initiator (AIBN), and reaction solvent (ethyl acetate) were then added to a nitrogen-purged three-necked flask equipped with a condenser. The reaction system was stirred at 80°C for 2 hours. The resulting polymer was precipitated in a poor solvent and dried under vacuum at 90°C for 8 hours to obtain the polymer corresponding to the following structural formula (b). In this embodiment, the molar ratio of precursor to initiator is 100:1, and the molar ratio of precursor to reaction solvent is 1:5.

[0056] S2. In an argon-filled glove box, 69 wt.% dimethoxymethane, 15 wt.% LiBF4, 7 wt.% of the polymer corresponding to the following structural formula (b), 7 wt.% of the polymer corresponding to the following structural formula (d), 0.5 wt.% 1,2-dimethoxybenzene, and 1.5 wt.% N,N-diethyltrimethylsilylamine are mixed and placed on a stirring device and stirred at 800 rpm for 30 min to obtain the electrolyte of this embodiment.

[0057] (b), n=550; (d), m=6.

[0058] Example 2 S1 is basically the same as step S1 in Example 1, except that: The second monomer is: ; The precursor is: ; In this embodiment, during the reaction stage of the precursor, initiator and reaction solvent, the reaction system is stirred at 80°C for 3 hours.

[0059] S2. In an argon-filled glove box, 68 wt.% dimethoxyethane, 10 wt.% LiTFSI, 5 wt.% LiDFOB, 8 wt.% of the polymer corresponding to the following structural formula (a), 6 wt.% of the polymer corresponding to the following structural formula (d), 1 wt.% 1,2-dimethoxybenzene, 1 wt.% N,N-dimethyltrifluoroacetamide, and 1 wt.% 2,3,5,6-tetrafluorop-diazabenzene are mixed and placed on a stirring device and stirred at 800 rpm for 30 min to obtain the electrolyte of this embodiment.

[0060] (a), n=750; (d), m=7.

[0061] Example 3 S1 is basically the same as step S1 in Example 2, except that: In this embodiment, the molar ratio of precursor to initiator is 200:1, and the molar ratio of precursor to reaction solvent is 1:10. S2. In an argon-filled glove box, 72 wt.% dimethoxymethane, 12 wt.% LiBOB, 6 wt.% of the polymer corresponding to the following structural formula (a), 8 wt.% of the polymer corresponding to the following structural formula (d), 1.2 wt.% 1,2-dimethoxybenzene, and 0.8 wt.% N,N-dimethyltrifluoroacetamide are mixed and placed on a stirring device and stirred at 800 rpm for 30 min to obtain the electrolyte of this embodiment.

[0062] (a), n=650; (d), m=7.

[0063] Example 4 S1 is basically the same as step S1 in Example 1, except that: The second monomer is: ; The precursor is: ; In this embodiment, the molar ratio of precursor to initiator is 200:1, and the molar ratio of precursor to reaction solvent is 1:10. During the reaction stage of precursor, initiator and reaction solvent, the reaction system is stirred at 80°C for 1 hour. S2. In an argon-filled glove box, 76 wt.% diethylene glycol dimethyl ether, 5 wt.% LiPF6, 5 wt.% LiBF4, 8 wt.% of the polymer corresponding to the following structural formula (c), 5 wt.% of the polymer corresponding to the following structural formula (d), 0.6 wt.% 1,2-dimethoxybenzene, and 0.4 wt.% 2,5-oxazolidinedione are mixed and placed on a stirring device and stirred at 800 rpm for 30 min to obtain the electrolyte of this embodiment.

[0064] (c), n=350; (d), m=5.

[0065] Example 5 S1. Basically the same as Example 4, except that: In this embodiment, the molar ratio of precursor to initiator is 100:1, and the molar ratio of precursor to reaction solvent is 1:5; during the reaction stage of precursor, initiator and reaction solvent, the reaction system is stirred at 80°C for 2 hours. S2. In an argon-filled glove box, 71 wt.% of 1,2-dimethoxypropane, 12 wt.% of LiPF6, 4 wt.% of the polymer corresponding to the following structural formula (c), 9 wt.% of the polymer corresponding to the following structural formula (d), 2 wt.% of N,N-diethyltrimethylsilylamine, and 2 wt.% of 2,5-oxazolidinedione are mixed and placed on a stirring device and stirred at 800 rpm for 30 min to obtain the electrolyte of this embodiment.

[0066] (c), n=550; (d), m=3.

[0067] Comparative Example 1 In an argon-filled glove box, 74 wt.% of 1,2-dimethoxyethane, 10 wt.% of LiTFSI, 5 wt.% of LiDFOB, 8 wt.% of the polymer corresponding to the following structural formula (a), 1 wt.% of 1,2-dimethoxybenzene, 1 wt.% of N,N-dimethyltrifluoroacetamide, and 1 wt.% of 2,3,5,6-tetrafluorop-diazabenzene were mixed and placed on a stirrer and stirred at 800 rpm for 30 min to obtain the electrolyte of this comparative example.

[0068] (a), n=750.

[0069] Comparative Example 2 In an argon-filled glove box, 78 wt.% dimethoxymethane, 12 wt.% LiBOB, 8 wt.% of the polymer corresponding to the following structural formula (d), 1.2 wt.% 1,2-dimethoxybenzene, and 0.8 wt.% N,N-dimethyltrifluoroacetamide were mixed and stirred at 800 rpm for 30 min on a stirrer to obtain the electrolyte of this comparative example.

[0070] (d), m=7.

[0071] Comparative Example 3 In an argon-filled glove box, 76 wt.% of 1,2-dimethoxypropane, 5 wt.% of LiPF6, 8 wt.% of the polymer corresponding to the following structural formula (c), 5 wt.% of the polymer corresponding to the following structural formula (e), 0.6 wt.% of 1,2-dimethoxybenzene, and 0.4 wt.% of 2,5-oxazolidinedione were mixed and placed on a stirrer and stirred at 800 rpm for 30 min to obtain the electrolyte of this comparative example.

[0072] (c), n=350; (e).

[0073] Test case (1) Ionic conductivity test: A 2cm² area was used as the test site. 2 Stainless steel gaskets and electrolytes are assembled into a battery. The battery is placed in a low-temperature test chamber at -20°C for 3 hours. Then, it is connected to an electrochemical workstation. The electrochemical workstation applies a sinusoidal voltage signal with an amplitude of 20mV and a test frequency range of 4MHz to 100MHz. The resistance of the electrolyte is recorded and the ionic conductivity is calculated.

[0074] (2) Discharge capacity test: The electrolytes obtained from each example and the comparative example were used to prepare test batteries; specifically, lithium iron phosphate was used as the positive electrode, lithium metal was used as the negative electrode, and polyvinylidene fluoride was used as the separator. The batteries were assembled into the battery casing to obtain the corresponding lithium batteries for each example.

[0075] Each assembled battery was placed in a high and low temperature test chamber at 25°C and left to stand for 1 hour. Then, it was connected to a charge / discharge apparatus and discharged at a rate of 0.2C with a discharge cutoff voltage of 2V. The capacity of the first discharge at 25°C was recorded (corresponding to...). Figure 1 The capacity value at cycle number 1 is recorded in Table 1. The battery is placed in a temperature chamber, which is heated from the ambient temperature to 75°C at a rate of 5°C / min and maintained at this temperature for 30 minutes. Then, the temperature chamber is cooled to 25°C at a rate of 1°C / min and maintained at this temperature for 30 minutes. The battery is then discharged at a rate of 0.2C with a discharge cutoff voltage of 2V. The discharge capacity (corresponding to...) is recorded. Figure 1 (The capacity value when the number of loops is 2). Repeat the above steps until 5 loops are generated, and plot the results. Figure 1 The capacity performance diagram shown.

[0076] (3) Phase transition temperature test: The phase transition temperature of the electrolyte is determined by measuring the transmittance of the electrolyte solution; the transmittance of the electrolyte solution is measured using a variable temperature ultraviolet-visible spectrometer; the solution is placed on the heating stage of the instrument and heated at a heating rate of 1℃ / min, and the transmittance curve is recorded. The temperature at which the transmittance reaches 0 is defined as the phase transition temperature.

[0077] The results of the above experiments (1) to (3) are recorded in Table 1 below.

[0078] Table 1

[0079] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. An electrolyte, characterized in that, The electrolyte includes an electron acceptor polymer and an electron donor polymer; The electron acceptor polymer includes at least one of the following polymers (a) to (c): (a); (b); (c); The electron donor polymer includes the following polymer (d): （d）； Furthermore, in polymers (a) to (c), n is independently selected from 100 to 1000, and in polymer (d), m is selected from 1 to 10.

2. The electrolyte according to claim 1, characterized in that, In the electrolyte, the content of the electron acceptor polymer is 3 wt.% to 12 wt.%, and the content of the electron donor polymer is 3 wt.% to 12 wt.%.

3. The electrolyte according to claim 1, characterized in that, The electrolyte also includes an organic solvent; The organic solvent includes at least one of carbonates or ethers, and / or, in the electrolyte, the content of the organic solvent is 65 wt.% to 80 wt.%.

4. The electrolyte according to claim 1, characterized in that, The electrolyte also includes lithium salt; The lithium salt includes at least one of LiPF6, LiBF4, LiFSI, LiTFSI, LiClO4, LiAsF6, LiBOB, and LiDFOB, and / or, in the electrolyte, the content of the lithium salt is 8 wt.% to 18 wt.%.

5. The electrolyte according to claim 1, characterized in that, The electrolyte also includes additives; The additive includes at least one of 1,2-dimethoxybenzene, 2,5-oxazolidinone, N,N-dimethyltrifluoroacetamide, 2,3,5,6-tetrafluorop-diazabenzene, and N,N-diethyltrimethylsilylamine, and / or, in the electrolyte, the content of the additive is 2 wt.% to 4 wt.%.

6. The electrolyte according to claim 1, characterized in that, The phase transition temperature of the electrolyte is 20℃~70℃.

7. The method for preparing the electrolyte according to any one of claims 1 to 6, characterized in that, include: The components of the electrolyte are thoroughly mixed to obtain the electrolyte.

8. A secondary battery, characterized in that, Includes the electrolyte as described in any one of claims 1 to 6.

9. The secondary battery according to claim 8, characterized in that, The secondary battery is a lithium-ion battery; The positive electrode of the lithium-ion battery includes one of lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, or ternary materials, and the negative electrode includes one of graphite, silicon, silicon-carbon composite material, or metallic lithium.

10. An electrical appliance, characterized in that, Includes the secondary battery as described in claim 8.

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