High-temperature-resistant electrolyte for lithium-manganese battery as well as preparation method and application of high-temperature-resistant electrolyte

Abstract

The invention provides a high-temperature-resistant electrolyte for a lithium-manganese battery and a preparation method and application of the high-temperature-resistant electrolyte, and belongs to the technical field of battery electrolytes.The high-temperature-resistant electrolyte comprises lithium salt, an organic solvent, a high-temperature-resistant additive and a flame retardant, and the high-temperature-resistant additive is polydimethylsiloxane, hexamethyldisilazane, fluoroethylene carbonate and 1, 2-propylene glycol; and one or more of 1, 3-propane sultone. Aiming at the defects of the existing electrolyte, the invention develops the electrolyte with high thermal stability and strong compatibility with the lithium elementary substance, and the electrolyte can still keep stable performance under the condition of long-time storage at 80 DEG C, and has good performance on parameters such as differential pressure, internal resistance after storage, electrolyte loss rate after storage and the like. The decomposition of the electrolyte under a high-temperature condition is reduced, the electrolyte is better matched with the system characteristics and the use environment of the lithium-manganese battery, and the application range and field of the lithium-manganese battery are widened.

Description

Technical Field

[0001] The present invention relates to the technical field of battery electrolytes, and in particular to a high temperature resistant electrolyte for lithium manganese batteries and a preparation method and application thereof. Background Art

[0002] Lithium-manganese batteries are used in scenarios that require long-term storage, maintenance-free or high energy density due to their advantages such as high energy density, low self-discharge rate and safety. However, due to the harsh environmental conditions in such scenarios and the need for long-term storage, higher requirements are placed on the high-temperature storage and working performance of lithium-manganese batteries.

[0003] The electrolyte is an important component of the battery. It is responsible for transferring ions between the positive and negative electrodes through the battery. It has an important impact on the battery's capacity, operating temperature range, storage performance and safety performance. Lithium-manganese batteries generate a lot of heat when working, and their internal temperature can reach above 90°C when working at a high rate. The most widely used electrolyte system in commercial applications is a mixed carbonate solution of lithium hexafluorophosphate. The solute lithium hexafluorophosphate in this system will decompose at 75°C, is sensitive to water, and is prone to produce HF to corrode the current collector and electrode active substances, causing the battery performance to decay rapidly; the solvent has a low boiling point and flash point, is easy to burn or explode, and causes safety problems. In addition, the most widely used commercial electrolytes are mostly used in lithium-ion batteries. The negative electrode of lithium-ion batteries is mainly a graphite negative electrode, while the negative electrode of lithium-manganese batteries is a metal lithium negative electrode. The electrochemical reaction mechanisms of the two are significantly different, which makes it difficult for existing secondary battery electrolytes to be used in lithium-manganese batteries. At the same time, the electrolytes of lithium primary batteries are currently mostly used at room temperature. There is still a lack of research on their use in high temperature environments (above 60°C), and the electrolyte system needs to be further modified. Summary of the invention

[0004] In view of the technical problems existing in the background technology, the present application provides a high temperature resistant electrolyte for lithium manganese batteries and its preparation method and application, aiming to solve the technical problems that the existing lithium manganese electrolyte is easy to decompose at high temperature, is flammable and explosive, and has low compatibility with lithium element.

[0005] In a first aspect, an embodiment of the present application provides a high temperature resistant electrolyte for a lithium manganese battery, the electrolyte comprising a lithium salt, an organic solvent, a high temperature resistant additive and a flame retardant, wherein the high temperature resistant additive is one or more of polydimethylsiloxane, hexamethyldisilazane, fluoroethylene carbonate, and 1,3-propanesultone.

[0006] In the technical solution of the embodiment of the present application, polydimethylsiloxane (PDMS) in the high temperature resistant additive can be successfully grafted on the surface of the metal oxide, and Si-OM (metal) bonds are formed with the help of -OH groups, forming an active surface to inhibit the formation of lithium dendrites; hexamethyldisilazane (HMDS) can increase the stability of the electrolyte and inhibit the electrolyte from LiPF during storage. 6 Hydrolysis and pyrolysis of the electrolyte reduce H 2 O and HF content.

[0007] Preferably, the high temperature resistant additive accounts for 0.5% to 2% of the total mass of the electrolyte.

[0008] Preferably, the flame retardant includes one or more of trimethyl phosphate, ethyl hexafluorophosphate, propyl pentafluorophosphate, phosphite, and dimethyl methylphosphonate.

[0009] In the technical solution of the embodiment of the present application, adding a flame retardant to the electrolyte can prevent the temperature from rising too quickly due to internal factors of the battery. When the additive is heated, it generates free radicals, which can capture H and hinder the occurrence of free radical chain exothermic reactions of hydrocarbons. The flame retardant should also have a large specific heat capacity to slow down the rate of temperature increase.

[0010] Preferably, the flame retardant accounts for 0.5% to 2% of the total mass of the electrolyte.

[0011] Preferably, the lithium salt includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium dioxalatoborate, lithium bis(trifluoromethylsulfonyl)imide, lithium trifluoromethylsulfonate, and lithium difluorooxalatoborate.

[0012] In the technical solution of the embodiment of the present application, the lithium salt used in the present application has high stability itself, and has high chemical and electrochemical stability with the current collector, active material, conductive agent, etc.

[0013] Preferably, the concentration of the lithium salt in the organic solvent is 0.8-1.2 mol / L.

[0014] Preferably, the organic solvent is one or more of propylene carbonate, dimethyl carbonate, ethylene carbonate, γ-butyrolactone, dimethyl sulfoxide, and sulfolane.

[0015] In the technical solution of the embodiment of the present application, a variety of solvents are selected for mixing. The mixed solvent has a high boiling point, a high flash point, a large dielectric constant and good stability, which helps to form a dense double SEI film on the surface of the electrode material, can better cover the surface of the negative electrode material, enhance the compatibility of the electrolyte with the lithium single negative electrode in the lithium manganese battery, and effectively reduce the reduction and decomposition of the contact surface between the electrolyte and the battery negative electrode material at high temperature, thereby increasing the storage stability of the battery and reducing the self-discharge rate of the battery.

[0016] In a second aspect, an embodiment of the present application provides a method for preparing a high temperature resistant electrolyte for a lithium manganese battery, comprising the following steps: adding a lithium salt to an organic solvent and mixing evenly, adding a high temperature resistant additive and a flame retardant thereto, stirring and dispersing under heating conditions, and obtaining an electrolyte after cooling.

[0017] Preferably, the heating temperature is 50-60°C.

[0018] In a third aspect, an embodiment of the present application provides a lithium manganese battery, comprising the above-mentioned high temperature resistant electrolyte, and the lithium manganese battery is a lithium manganese primary battery.

[0019] Different from the existing technical solutions, the beneficial effects of this application include: In view of the shortcomings of existing electrolytes, this application has developed an electrolyte with high thermal stability and strong compatibility with lithium. It can still maintain stable performance under long-term storage conditions at 80°C, and has good performance in parameters such as pressure difference, internal resistance after storage, and electrolyte loss rate after storage. It reduces the decomposition of the electrolyte under high temperature conditions, and better matches the characteristics and use environment of the lithium-manganese battery system, broadening the scope and field of application of lithium-manganese batteries.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. DETAILED DESCRIPTION

[0021] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the description and claims of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0023] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0026] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0027] At present, the most widely used electrolytes are mostly used in lithium-ion batteries. The negative electrode of lithium-ion batteries is mainly graphite, while the negative electrode of lithium-manganese batteries is metal lithium. The electrochemical reaction mechanisms of the two are significantly different, which makes it difficult for existing secondary battery electrolytes to be used in lithium-manganese batteries. At the same time, the electrolytes of lithium primary batteries are mostly used in room temperature environments. There is still a lack of research on their use in high temperature environments (above 60°C), and the electrolyte system needs to be further modified.

[0028] In order to solve the technical problems that the existing lithium manganese electrolyte is easy to decompose, flammable and explosive at high temperature, and has low compatibility with lithium, this application provides a high temperature resistant electrolyte for lithium manganese battery and its preparation method and application, and develops an electrolyte with high thermal stability and strong compatibility with lithium. It can still maintain stable performance under the condition of long-term storage at 80°C, and has good performance in parameters such as pressure difference, internal resistance after storage, and electrolyte loss rate after storage. It reduces the decomposition of the electrolyte under high temperature conditions, and better matches the characteristics and use environment of the lithium manganese battery system, broadening the scope and field of application of lithium manganese batteries.

[0029] In a first aspect, an embodiment of the present application provides a high temperature resistant electrolyte for a lithium manganese battery, the electrolyte comprising a lithium salt, an organic solvent, a high temperature resistant additive and a flame retardant, wherein the high temperature resistant additive is one or more of polydimethylsiloxane, hexamethyldisilazane, fluoroethylene carbonate, and 1,3-propanesultone.

[0030] In the technical solution of the embodiment of the present application, polydimethylsiloxane (PDMS) in the high temperature resistant additive can be successfully grafted on the surface of the metal oxide, and Si-OM (metal) bonds are formed with the help of -OH groups, forming an active surface to inhibit the formation of lithium dendrites; hexamethyldisilazane (HMDS) can increase the stability of the electrolyte and inhibit the electrolyte from LiPF during storage. 6 Hydrolysis and pyrolysis of the electrolyte reduce H 2 O and HF content.

[0031] Preferably, the high temperature resistant additive accounts for 0.5% to 2% of the total mass of the electrolyte.

[0032] Preferably, the flame retardant includes one or more of trimethyl phosphate, ethyl hexafluorophosphate, propyl pentafluorophosphate, phosphite, and dimethyl methylphosphonate.

[0033] In the technical solution of the embodiment of the present application, adding a flame retardant to the electrolyte can prevent the temperature from rising too quickly due to internal factors of the battery. When the additive is heated, it generates free radicals, which can capture H and hinder the occurrence of free radical chain exothermic reactions of hydrocarbons. The flame retardant should also have a large specific heat capacity to slow down the rate of temperature increase.

[0034] Preferably, the flame retardant accounts for 0.5% to 2% of the total mass of the electrolyte.

[0035] Preferably, the lithium salt includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium dioxalatoborate, lithium bis(trifluoromethylsulfonyl)imide, lithium trifluoromethylsulfonate, and lithium difluorooxalatoborate.

[0036] In the technical solution of the embodiment of the present application, the lithium salt used in the present application has high stability itself, and has high chemical and electrochemical stability with the current collector, active material, conductive agent, etc.

[0037] Preferably, the concentration of the lithium salt in the organic solvent is 0.8-1.2 mol / L.

[0038] Preferably, the organic solvent is one or more of propylene carbonate, dimethyl carbonate, ethylene carbonate, γ-butyrolactone, dimethyl sulfoxide, and sulfolane.

[0039] In the technical solution of the embodiment of the present application, a variety of solvents are selected for mixing. The mixed solvent has a high boiling point, a high flash point, a large dielectric constant and good stability, which helps to form a dense double SEI film on the surface of the electrode material, can better cover the surface of the negative electrode material, and effectively reduce the reduction and decomposition of the contact surface between the electrolyte and the battery negative electrode material at high temperature, thereby increasing the storage stability of the battery and reducing the self-discharge rate of the battery.

[0040] In a second aspect, an embodiment of the present application provides a method for preparing a high temperature resistant electrolyte for a lithium manganese battery, comprising the following steps: adding a lithium salt to an organic solvent and mixing evenly, adding a high temperature resistant additive and a flame retardant thereto, stirring and dispersing under heating conditions, and obtaining an electrolyte after cooling.

[0041] Preferably, the heating temperature is 50-60°C.

[0042] In a third aspect, an embodiment of the present application provides a lithium manganese battery, including the above-mentioned high temperature resistant electrolyte lithium manganese battery as a lithium manganese primary battery.

[0043] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained commercially.

[0044] 1. Preparation method Example 1 Preparation method of high temperature resistant lithium manganese battery electrolyte: at room temperature, in a glove box, take 60 ml of dimethyl carbonate, 30 ml of ethylene carbonate, and 10 ml of γ-butyrolactone, respectively, and mix them evenly, then add 0.098 mol of lithium hexafluorophosphate and 0.002 mol of lithium dioxalate borate to the prepared solvent, so that the concentration of lithium hexafluorophosphate and lithium dioxalate borate mixture in the organic solvent is 1 mol / L, and then add 2.81 g of polydimethylsiloxane and 2.81 g of trimethyl phosphate to the prepared solvent to prepare an electrolyte of corresponding concentration, the high temperature resistant additive and the flame retardant respectively account for 2% of the mass of the battery electrolyte, stir the obtained electrolyte at 55°C until it is completely dissolved, cool to room temperature, and stir the obtained electrolyte evenly to obtain the electrolyte of this embodiment.

[0045] Example 2 Preparation method of high temperature resistant lithium manganese battery electrolyte: at room temperature, in a glove box, take 60 ml of dimethyl carbonate, 30 ml of ethylene carbonate, and 10 ml of γ-butyrolactone, respectively, and mix them evenly, then add 0.096 mol of lithium hexafluorophosphate and 0.004 mol of lithium dioxalate borate to the prepared solvent, so that the concentration of lithium hexafluorophosphate and lithium dioxalate borate mixture in the organic solvent is 1 mol / L, and then add 2.81 g of ethyl hexafluorophosphate and 2.81 g of fluoroethylene carbonate to the prepared solvent to prepare an electrolyte of corresponding concentration, the high temperature resistant additive and the flame retardant respectively account for 2% of the mass of the battery electrolyte, stir the obtained electrolyte at 60°C until it is completely dissolved, cool to room temperature, and stir the obtained electrolyte evenly to obtain the electrolyte of this embodiment.

[0046] Example 3 Preparation method of high temperature resistant lithium manganese battery electrolyte: at room temperature, in a glove box, take 60 ml of dimethyl carbonate, 30 ml of ethylene carbonate, and 10 ml of γ-butyrolactone, respectively, and mix them evenly, then add 0.094 mol of lithium hexafluorophosphate and 0.006 mol of lithium dioxalate borate to the prepared solvent, so that the concentration of lithium hexafluorophosphate and lithium dioxalate borate mixture in the organic solvent is 1 mol / L, and then add 2.81 g of polydimethylsiloxane and 2.81 g of fluoroethylene carbonate to the prepared solvent to prepare an electrolyte of corresponding concentration, the high temperature resistant additive and the flame retardant respectively account for 2% of the mass of the battery electrolyte, stir the obtained electrolyte at 50°C until it is completely dissolved, cool to room temperature, and stir the obtained electrolyte evenly to obtain the electrolyte of this embodiment.

[0047] Example 4 Preparation method of high temperature resistant lithium manganese battery electrolyte: at room temperature, in a glove box, take 60 ml of dimethyl carbonate, 30 ml of ethylene carbonate, and 10 ml of γ-butyrolactone, respectively, and mix them evenly, then add 0.092 mol of lithium hexafluorophosphate and 0.008 mol of lithium dioxalate borate to the prepared solvent, so that the concentration of lithium hexafluorophosphate and lithium dioxalate borate mixture in the organic solvent is 1 mol / L, and then add 2.81 g of polydimethylsiloxane and 2.81 g of fluoroethylene carbonate to the prepared solvent to prepare an electrolyte of corresponding concentration, the high temperature resistant additive and the flame retardant respectively account for 2% of the mass of the battery electrolyte, stir the obtained electrolyte at 60°C until it is completely dissolved, cool to room temperature, and stir the obtained electrolyte evenly to obtain the electrolyte of this embodiment.

[0048] Comparative Example 1 The room temperature electrolyte of a lithium manganese battery comprises an organic solvent composed of dimethyl carbonate and ethylene carbonate in a volume ratio of 1:1; and lithium hexafluorophosphate in an organic solvent concentration of 1 mol / L.

[0049] Comparative Example 2 The room temperature electrolyte of a lithium manganese battery comprises an organic solvent consisting of dimethyl carbonate and ethylene carbonate in a volume ratio of 1:1; lithium hexafluorophosphate in an organic solvent concentration of 1 mol / L; and polydimethylsiloxane accounting for 2% of the electrolyte mass.

[0050] Comparative Example 3 The room temperature electrolyte of a lithium manganese battery comprises an organic solvent consisting of dimethyl carbonate and ethylene carbonate in a volume ratio of 1:1; lithium hexafluorophosphate in an organic solvent concentration of 1 mol / L; and polyfluoroethylene carbonate accounting for 2% of the electrolyte mass.

[0051] Comparative Example 4 The room temperature electrolyte of a lithium manganese battery comprises an organic solvent consisting of dimethyl carbonate and ethylene carbonate in a volume ratio of 1:1; lithium hexafluorophosphate in an organic solvent concentration of 1 mol / L; and polydimethylsiloxane and polyfluoroethylene carbonate each accounting for 5% of the mass of the electrolyte.

[0052] 2. Test Method 1. High temperature storage test method: Battery preparation: A mixture of manganese dioxide, expanded graphite and Ketjen black is used as the positive electrode of the battery, a lithium ribbon is used as the negative electrode of the battery, and the diaphragm is a polypropylene ceramic diaphragm. The electrolyte is injected to make a soft-pack lithium-manganese primary battery.

[0053] The main test steps of high temperature storage test are as follows: a) Place the sample in a high temperature test chamber at 80°C; b) After 7 days, take out the battery from the high temperature test chamber, wipe it clean, and store it in a desiccator for at least 2 hours before weighing it; c) Then place the sample in a high temperature test chamber and store it for 21 days (28 days in total); d) Take out the sample and observe the battery status to check whether there is swelling or leakage, and test the battery internal resistance and pressure difference.

[0054] e) Wipe the batteries clean and store them in a desiccator for at least 2 hours before weighing them.

[0055] f) Calculate the electrolyte loss rate based on the weight percentage of the electrolyte loss of the sample from the 7th day to the 28th day and the mass percentage of the electrolyte initially injected:

[0056] Where: M L —Loss rate of monomer electrolyte, %; M 0 —The mass of the single cell before the electrolyte is injected, g; M 1 —Mass of single battery, g; M 2 —The mass of the single battery after 7 days, g; M 3 —The mass of the single cell after 28 days, g.

[0057] 2. Heating test method: Place the battery in a high temperature test chamber, and heat it from ambient temperature to 90°C at a heating rate of 5°C / min and keep it for 2 hours. Observe whether the sample releases. If not, continue to heat it to 149°C and keep the temperature for 2 hours. After 2 hours, observe the battery status. The qualified criterion is: no smoke, no fire, and no explosion.

[0058] III. Analysis of test results of various embodiments and comparative examples (1) The electrolytes prepared in Examples 1 to 4 and Comparative Example 1 were used to prepare lithium manganese batteries. The prepared batteries were subjected to a high temperature storage test. The test results are shown in Table 1 below.

[0059] Table 1 Storage test results of various embodiments and comparative examples

[0060] As can be seen from Table 1, the lithium manganese battery prepared using the formulas in Examples 1 to 4 has good stability under high temperature conditions, while the lithium manganese battery in Comparative Example 1 swells and leaks, proving that adding a high temperature resistant additive to the electrolyte can effectively improve the high temperature resistance of the lithium manganese battery. It can be seen from Comparative Examples 2 and 3 that adding a single component of high temperature resistant additives or flame retardants at the same time cannot effectively prevent the battery from swelling due to high temperature storage. It can be seen from Comparative Example 4 that when the content of the high temperature resistant additive or flame retardant is too high, it has a significant impact on the ion transportability of the electrolyte and has a negative effect on the electrical performance of the battery, so it is necessary to control the ratio of the addition of the two.

[0061] (2) The electrolytes prepared in Examples 1 to 4 and Comparative Example 1 were used to prepare lithium manganese batteries. The batteries were placed in a high-temperature test box and subjected to a heating test. The test results are shown in Table 2 below.

[0062] Table 2 Heating test results of various embodiments and comparative examples

[0063] It can be seen from Table 2 that adding flame retardants to the electrolyte can effectively improve the flame retardant properties of lithium manganese batteries.

[0064] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A high temperature resistant electrolyte for lithium manganese battery, characterized in that: The electrolyte comprises lithium salt, organic solvent, high temperature resistant additive and flame retardant, wherein the high temperature resistant additive is one or more of polydimethylsiloxane, hexamethyldisilazane, fluoroethylene carbonate and 1,3-propane sultone.

2. The high temperature electrolyte for lithium manganese battery according to claim 1, characterized in that: The high temperature resistant additive accounts for 0.5% to 2% of the total mass of the electrolyte.

3. The high temperature resistant electrolyte for lithium manganese battery according to claim 1, characterized in that: The flame retardant includes one or more of trimethyl phosphate, ethyl hexafluorophosphate, propyl pentafluorophosphate, phosphite, and dimethyl methylphosphonate.

4. The high temperature resistant electrolyte for lithium manganese battery according to claim 1, characterized in that: The flame retardant accounts for 0.5% to 2% of the total mass of the electrolyte.

5. The high temperature resistant electrolyte for lithium manganese battery according to claim 1, characterized in that: The lithium salt includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium dioxalatoborate, lithium bis(trifluoromethylsulfonyl)imide, lithium trifluoromethylsulfonate, and lithium difluorooxalatoborate.

6. The high temperature resistant electrolyte for lithium manganese battery according to claim 1, characterized in that: The concentration of the lithium salt in the organic solvent is 0.8-1.2 mol / L.

7. The high temperature resistant electrolyte for lithium manganese battery according to claim 1, characterized in that: The organic solvent is one or more of propylene carbonate, dimethyl carbonate, ethylene carbonate, γ-butyrolactone, dimethyl sulfoxide, and sulfolane.

8. A method for preparing a high temperature resistant electrolyte for a lithium manganese battery according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: adding lithium salt into an organic solvent and mixing evenly, adding a high temperature resistant additive and a flame retardant thereto, stirring and dispersing under heating conditions, and obtaining an electrolyte after cooling.

9. The method for preparing a high temperature resistant electrolyte for a lithium manganese battery according to claim 8, characterized in that: The heating temperature is 50-60°C.

10. A lithium manganese battery, characterized in that: The invention comprises the high temperature resistant electrolyte according to any one of claims 1 to 7, wherein the lithium manganese battery is a lithium manganese primary battery.

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