Electrolyte of total chlorine solvent and electrochemical device

Abstract

The invention relates to an electrolyte of a whole-chlorine solvent and an electrochemical device, the electrolyte of the whole-chlorine solvent comprises electrolyte salt and the whole-chlorine solvent, and the whole-chlorine solvent is composed of chlorinated ether and chlorinated carbonic ester. The electrolyte of the whole-chlorine solvent provided by the invention adopts the chlorinated ether and the chlorinated carbonate as the solvent of the electrolyte, does not contain flash point components, and has low volatility, low inflammability, flame retardance and compatibility with positive and negative electrodes, so that the battery shows good electrochemical performance and relatively high safety.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to an electrolyte of a perchlorinated solvent and an electrochemical device. Background Art

[0002] At present, lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and energy storage systems due to their advantages such as high energy density and long cycle life.

[0003] However, the application of lithium-ion batteries is limited by safety issues. Under extreme conditions such as overcharging, short circuit or mechanical damage, lithium-ion batteries may experience thermal runaway, causing the battery to overheat, swell or even burn. Moreover, the lithiated graphite anode in lithium-ion batteries may react with the components in the electrolyte at high temperatures, releasing a large amount of heat, further aggravating the aforementioned thermal runaway process. In addition, the existing electrolyte is highly flammable, which will also aggravate the aforementioned thermal runaway problem. Summary of the invention

[0004] In view of this, in order to solve at least one of the above technical problems, the present application provides an electrolyte of a perchlorinated solvent.

[0005] In addition, the present application also provides an electrochemical device using the electrolyte of the aforementioned perchlorinated solvent.

[0006] The embodiment of the present application provides an electrolyte of a perchlorinated solvent, which includes: an electrolyte salt and a perchlorinated solvent, wherein the perchlorinated solvent is composed of a chlorinated ether and a chlorinated carbonate.

[0007] In some possible embodiments, the chloroether is a linear chloroether.

[0008] In some possible embodiments, the chloroether has a general structural formula as shown in formula (I): (I), Among them, R 1 and R 2 Each of the following is independently selected from chlorine and alkyl chloride, and n is an integer of 1 to 10.

[0009] In some possible embodiments, the chlorocarbonate is a cyclic chlorocarbonate.

[0010] In some possible embodiments, the chlorocarbonate has a general structural formula as shown in formula (II): (II), Among them, R 3 and R 4 Each of the following is independently selected from chlorine and alkyl chloride, and n is an integer of 1 to 10.

[0011] In some possible embodiments, the chloroether includes at least one of bis[2-(2-chloroethoxy)ethyl]ether, 1,2-bis(2-chloroethoxy)ethane, chloromethyl ether, chloroethyl ether, chloropropyl ether and chlorobutyl ether.

[0012] In some possible embodiments, the chlorinated carbonate includes at least one of chloroethylene carbonate and dichloroethylene carbonate.

[0013] In some possible embodiments, in the perchlorinated solvent, the volume ratio of the chlorinated ether to the chlorinated carbonate is 1:(0.1~1).

[0014] In some possible embodiments, the electrolyte salt is a lithium salt, and the lithium salt includes Li 2 SO 4 、LiClO 4 、LiNO 3 、LiCl、LiCF 3 SO 3 、LiPF 6 、Li(FSO 2 ) 2 N, LiBF 4 、LiDFOB、Li(CF 3 CF 2 SO 2 ) 2 N and Li(CF 3 SO 2 ) 2 At least one of N.

[0015] An embodiment of the present application also provides an electrochemical device, which includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte of the aforementioned perchlorinated solvent, wherein the separator is disposed between the positive electrode sheet and the negative electrode sheet.

[0016] Compared with the prior art, the electrolyte of the perchlorinated solvent provided in the embodiment of the present application is composed of chloroether and chlorocarbonate. Chloroether and chlorocarbonate have lower volatility and low flammability than traditional organic solvents, and chlorine atoms can react with free radicals in the flame to inhibit combustion, play a flame retardant role, thereby reducing the release and combustion risk of toxic gases. Therefore, the electrolyte can have the characteristics of low volatility and high flame retardancy, which can effectively reduce the risk of electrolyte combustion and improve the flame retardant effect of the electrolyte on the negative electrode of the electrochemical device, thereby enhancing the safety of the electrolyte. At the same time, since the electrolyte has a weak solvation structure, it helps anions (such as chloride ions) to form a protective interface layer on the electrode surface, and chlorocarbonate also helps to form a stable organic layer on the electrode surface to further protect the electrode, so the electrolyte has high compatibility with both positive and negative electrodes. In addition, the electrolyte has high kinetic performance at the contact interface with the positive and negative electrodes, which is conducive to the rapid transmission and reaction of electrolyte ions. The electrochemical device using the electrolyte has both good electrochemical performance and high safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a graph of the mass fraction of common battery components and combustion heat generation.

[0018] Figure 2 This is a graph showing the results of the electrolyte self-extinguishing test in Example 1 and Comparative Examples 1-2 of the present application, wherein Figure 2 a is the electrolyte self-extinguishing test result of comparative example 1, Figure 2 b is the electrolyte self-extinguishing test result of comparative example 2, Figure 2 c is the electrolyte self-extinguishing test result of Example 1.

[0019] Figure 3 This is a graph showing the flame retardancy test results of the electrolyte negative electrode in Example 1 and Comparative Examples 1-2 of the present application, wherein Figure 3 a is the flame retardant test result of the negative electrode of the electrolyte in comparative example 1, Figure 3 b is the flame retardant test result of the negative electrode of the electrolyte in comparative example 2, Figure 3 c is the flame retardancy test result of the negative electrode of the electrolyte in Example 1.

[0020] Figure 4 This is a test chart of the cycle performance of batteries prepared with the electrolytes in Example 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0022] See also Figure 1The inventors of this application have found that the heat released during the combustion of lithium batteries mainly comes from the negative electrode material and the electrolyte. The negative electrode material, especially the lithium graphite negative electrode, may react with the components in the electrolyte at high temperatures, releasing a large amount of heat, further aggravating the process of thermal runaway.

[0023] To this end, the present invention provides an electrolyte of a perchlorinated solvent, which includes an electrolyte salt and a perchlorinated solvent, wherein the perchlorinated solvent is composed of a chlorinated ether and a chlorinated carbonate. The electrolyte of the perchlorinated solvent provided in the present invention has both low volatility and high flame retardancy.

[0024] Among them, chloroethers can effectively improve the electrochemical performance and safety of batteries. First, chloroethers have good solubility and can effectively dissolve electrolyte salts, such as lithium salts, to improve the ionic conductivity of the electrolyte, thereby improving the performance of the battery. Secondly, chloroethers have good stability, which can enhance the stability of the electrolyte, reduce the decomposition of the electrolyte, and reduce the adverse reactions between the electrolyte and the electrode materials, thereby improving the intrinsic safety of the electrolyte. Especially under high temperature, high voltage or abuse conditions, the stability of chloroethers helps to reduce the safety hazards when the battery is overheated, thereby improving the safety of the battery. In addition, chloroethers can also form a protective interface layer on the electrode surface, reduce interface side reactions, and reduce the corrosion reaction between the electrolyte and the electrode, thereby extending the service life of the battery. Through the above mechanism, chloroethers not only improve the performance of the battery, but also effectively reduce the risk of thermal runaway and improve the safety of the battery.

[0025] Chlorocarbonates can form a stable organic film on the surface of the positive and negative electrodes of the battery. This film can not only effectively isolate the direct contact between the electrolyte and the electrode material, reduce the occurrence of side reactions, and extend the service life of the battery, but also improve the interface stability and kinetic performance of the positive and negative electrode materials, and reduce the stress caused by the volume change of the electrode material during the charge and discharge process, thereby improving the cycle performance and rate performance of the battery. Chlorocarbonates also have good stability, which helps to improve the thermal stability of the battery, reduce the risk of thermal runaway of the battery, and enhance the safety of the battery under high temperature, high pressure or abuse conditions.

[0026] Chloroether and chlorocarbonate are used together as solvents for the electrolyte. The synergistic effect of the two can effectively improve the intrinsic safety of the electrolyte and the overall thermal stability of the battery. Chlorine atoms can react with free radicals in the flame to inhibit combustion, so that the electrolyte has high flame retardancy. When the battery is facing high temperature or other external heat sources, it can effectively slow down or prevent the combustion of the electrolyte, thereby reducing the possibility of safety risks such as thermal runaway, fire or explosion of the battery. In addition, chloroether and chlorocarbonate also improve the electrochemical performance of the battery.

[0027] The chloroether can be a linear chloroether, which can further improve the interaction with the lithium salt, thereby enhancing the solubility of the lithium salt and improving the ionic conductivity of the electrolyte. The linear chloroether has low volatility, which further improves the thermal stability of the electrolyte. In addition, the linear chloroether also has low viscosity, can still maintain good fluidity at low temperatures, and improves the low temperature performance of the battery.

[0028] Specifically, the chloroether has a general structural formula as shown in formula (I): (I), Among them, R 1 and R 2 Each of the chloroalkyl groups is independently selected from chlorine and chloroalkyl, and n is an integer of 1 to 10. Further, the chloroalkyl group may include at least one of monochloromethyl, dichloromethyl, trichloromethyl, monochloroethyl and monochlorobutyl.

[0029] In some embodiments, the chloroether may include at least one of bis[2-(2-chloroethoxy)ethyl]ether, 1,2-bis(2-chloroethoxy)ethane, chloromethyl ether, chloroethyl ether, chloropropyl ether, and chlorobutyl ether. The chloroether may further include at least one of [2-(2-chloroethoxy)ethyl]ether and 1,2-bis(2-chloroethoxy)ethane. The above chloroethers can make the electrolyte have good lithium salt solubility and interface stability.

[0030] The chlorinated carbonate may be a cyclic chlorinated carbonate, which is conducive to further reacting with the surface of the electrode material during the charge and discharge process, forming a stable organic interface layer on the surface of the electrode material, and further improving the battery interface stability and thermal stability. At the same time, the stable interface layer helps to protect the electrode under heat and reduce the generation of gas.

[0031] Specifically, the chlorocarbonate has a general structural formula as shown in formula (II): (II), Among them, R 3 and R 4 Each of the chloroalkyl groups is independently selected from chlorine and chloroalkyl, and n is an integer of 1 to 10. Further, the chloroalkyl group may include at least one of monochloromethyl, dichloromethyl, trichloromethyl, monochloroethyl and monochlorobutyl.

[0032] In some embodiments, the chlorocarbonate may include at least one of chloroethylene carbonate and dichloroethylene carbonate. The chlorocarbonate enables the battery to have better interfacial film-forming performance and further improves the thermal stability of the battery. The chlorocarbonate may further be chloroethylene carbonate.

[0033] In the electrolyte provided in the embodiment of the present application, the solvent is composed only of chloroether and chlorocarbonate, which is a fully chlorinated solvent. Existing electrolytes usually contain low flash point components (such as ethyl methyl carbonate, dimethyl carbonate, etc.) to increase the conductivity of the electrolyte, but low flash point components may cause safety issues. The electrolyte provided in the embodiment of the present application uses chloroether and chlorocarbonate as solvents, which can improve the thermal safety of the electrolyte while satisfying the conductivity of the electrolyte, reduce or avoid the addition of low flash point components, and meet the dual requirements of conductivity and safety of the electrolyte.

[0034] In the electrolyte of the perchlorinated solvent, the volume ratio of the chloroether and the chlorocarbonate can be 1: (0.1~1). Within this range, a good balance between the solubility of the electrolyte salt and the interfacial film-forming performance can be achieved, further improving the battery's electrical performance and safety. Exemplarily, the volume ratio of the chloroether and the chlorocarbonate can be 1: 0.1, 1: 0.2, 1: 0.25, 1: 0.3, 1: 0.4, 1: 0.5, 1: 0.6, 1: 0.7, 1: 08, 1: 0.9, 1: 1 or any value within the range of values ​​composed of any two of the above values. Further, the volume ratio of the chloroether and the chlorocarbonate can be 1: (0.2~0.5).

[0035] The electrolyte salt may be a lithium salt, which may include Li 2 SO 4 、LiClO 4 、LiNO 3 、LiCl、LiCF 3 SO 3 、LiPF 6 、Li(FSO 2 ) 2 N, LiBF 4 、LiDFOB、Li(CF 3 CF 2 SO 2 ) 2 N and Li(CF 3 SO 2 ) 2 At least one of N, etc. It is understandable that the electrolyte salt includes but is not limited to the above-mentioned lithium salt, and a suitable electrolyte salt can be selected according to different application requirements.

[0036] Compared with the prior art, the electrolyte of the perchlorinated solvent provided in the embodiment of the present application has the following beneficial effects: 1. Use chloroethers and chlorocarbonates as perchlorinated solvents for electrolytes: On the one hand, chloroethers can efficiently dissolve electrolyte salts, improving the conductivity and intrinsic safety of the electrolyte; on the other hand, chlorocarbonates can improve the film-forming properties of the electrolyte, forming a stable organic film on the surface of the positive and negative electrodes of the battery, effectively isolating the direct contact between the electrolyte and the electrode material, and improving the battery's cycle performance, rate performance, and overall thermal stability. Through the synergistic effect of the two, the electrolyte has low volatility, high flame retardancy, and good electrochemical properties.

[0037] 2. Further use of linear chloroethers and / or cyclic chlorocarbonates can increase the overall flash point of the electrolyte and further improve the safety of the battery.

[0038] 3. The solvent of the electrolyte is composed only of chlorinated ethers and chlorinated carbonates, which is a fully chlorinated solvent. No low-flash point components are added to the fully chlorinated solvent, which can further improve the safety of the electrolyte while ensuring the conductivity of the electrolyte.

[0039] The present application also provides an electrochemical device, comprising a positive electrode sheet, a negative electrode sheet, a diaphragm and an electrolyte, wherein the electrolyte is the electrolyte of the aforementioned perchlorinated solvent. Specifically, the diaphragm is disposed between the positive electrode sheet and the negative electrode sheet.

[0040] The electrolyte adopts the electrolyte of the aforementioned perchlorinated solvent. Since the solvent of the electrolyte is composed of chloroethers and chlorocarbonates, chloroethers and chlorocarbonates have the characteristics of low volatility, low flammability and flame retardancy, which can effectively reduce the risk of electrolyte combustion and improve the flame retardant effect of the electrolyte on the negative electrode of the electrochemical device, thereby enhancing the safety of the electrolyte. At the same time, the electrolyte has high compatibility with both the positive and negative electrodes, and has high kinetic properties at the contact interface with the positive and negative electrodes, which is conducive to the rapid transmission and reaction of electrolyte ions. Therefore, the electrochemical device using the electrolyte of the aforementioned perchlorinated solvent has both good electrochemical performance and high safety. The application of the electrolyte of the perchlorinated solvent provided in the embodiment of the present application in the battery provides a new path for achieving high-safety batteries.

[0041] Specifically, the electrochemical device can be a lithium battery, the positive electrode plate can include positive electrode materials such as lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt oxide, nickel cobalt manganese ternary positive electrode material and nickel cobalt aluminum ternary positive electrode material, and the negative electrode plate can be a lithiated graphite negative electrode.

[0042] The electrolyte and electrochemical device of the above-mentioned perchlorinated solvent are further described below through specific examples.

[0043] Example 1 This embodiment provides an electrolyte of a perchlorinated solvent, the electrolyte comprising: an electrolyte salt, a chloroether and a chlorocarbonate. The electrolyte salt is LiDFOB and Li(FSO2 ) 2 N, the chloroether is bis[2-(2-chloroethoxy)ethyl]ether, the chlorocarbonate is ethylene carbonate, the volume ratio of bis[2-(2-chloroethoxy)ethyl]ether to ethylene carbonate in the electrolyte is 1:0.25, and the electrolyte salt is Li(FSO 2 ) 2 The concentration of N is 3.5 mol·L -1 , the concentration of LiDFOB is 2 wt% of the total mass of the electrolyte, and the electrolyte is a fully chlorinated solvent electrolyte (ACSE1).

[0044] The specific preparation method includes the following steps, which can be carried out in an argon-filled glove box: Step S1, weigh 0.0035 mol Li(FSO 2 ) 2 N salt.

[0045] Step S2: Li(FSO 2 ) 2 The N salt was dissolved in a mixed solution of 0.8 mL of bis[2-(2-chloroethoxy)ethyl]ether and 0.2 mL of ethylene chloride carbonate.

[0046] Step S3, adding LiDFOB salt with a mass fraction of 2 wt% of the electrolyte and mixing well to obtain ACSE1.

[0047] Example 2 This embodiment provides an electrolyte of a perchlorinated solvent, the electrolyte comprising: an electrolyte salt, a chloroether and a chlorocarbonate. The electrolyte salt is LiDFOB and Li(FSO 2 ) 2 N, the chloroether is bis[2-(2-chloroethoxy)ethyl]ether, the chlorocarbonate is ethylene carbonate, the volume ratio of bis[2-(2-chloroethoxy)ethyl]ether to ethylene carbonate in the electrolyte is 1:0.5, and the electrolyte salt concentration is approximately Li(FSO 2 ) 2 N is 3.5 mol·L -1 , LiDFOB is 2 wt% of the total mass of the electrolyte, and the electrolyte is a fully chlorinated solvent electrolyte (ACSE2).

[0048] The specific preparation method includes the following steps, which can be carried out in an argon-filled glove box: Step S1, weigh 0.0035 mol Li(FSO 2 ) 2 N salt.

[0049] Step S2: Li(FSO2 ) 2 The N salt was dissolved in a mixed solution of 0.67 mL of bis[2-(2-chloroethoxy)ethyl]ether and 0.33 mL of ethylene chloride carbonate.

[0050] Step S3, adding LiDFOB salt with a mass fraction of 2 wt% of the electrolyte and mixing evenly to obtain ACSE2.

[0051] Example 3 This embodiment provides an electrolyte of a perchlorinated solvent, the electrolyte comprising: an electrolyte salt, a chloroether and a chlorocarbonate. The electrolyte salt is LiDFOB and Li(FSO 2 ) 2 N, the chlorinated ether is 1,2-bis(2-chloroethoxy)ethane, the chlorinated carbonate is chloroethylene carbonate, the volume ratio of 1,2-bis(2-chloroethoxy)ethane to chloroethylene carbonate in the electrolyte is 1:0.25, and the electrolyte salt concentration is approximately Li(FSO 2 ) 2 N is 3.5 mol·L -1 , LiDFOB is 2wt% of the total mass of the electrolyte, and the electrolyte is a fully chlorinated solvent electrolyte (ACSE3).

[0052] The specific preparation method includes the following steps, which can be carried out in an argon-filled glove box: Step S1, weigh 0.0035 mol Li(FSO 2 ) 2 N salt.

[0053] Step S2: Li(FSO 2 ) 2 The N salt was dissolved in a mixed solution of 0.8 ml 1,2-bis(2-chloroethoxy)ethane and 0.2 ml chloroethylene carbonate.

[0054] Step S3, adding LiDFOB salt with a mass fraction of 2 wt% of the electrolyte and mixing evenly to obtain ACSE3.

[0055] Comparative Example 1 This comparative example provides a carbonate-based electrolyte, which includes an electrolyte salt and a carbonate-based solvent. The electrolyte salt is LiPF 6 The carbonate-based solvents are ethylene carbonate and dimethyl carbonate. The volume ratio of ethylene carbonate to dimethyl carbonate in the carbonate-based electrolyte is 1:1, and the electrolyte salt concentration is approximately 1 mol·L -1 .

[0056] The specific preparation method includes the following steps, which can be carried out in an argon-filled glove box: Step S1, weigh 0.001 mol LiPF 6 Salt.

[0057] Step S2: LiPF 6 The salt was dissolved in 0.5 mL of ethylene carbonate and 0.5 mL of dimethyl carbonate and mixed well to obtain an electrolyte.

[0058] Comparative Example 2 This comparative example provides an ether electrolyte solution, which includes: an electrolyte salt and an ether solvent. The electrolyte salt is Li(FSO 2 ) 2 N, namely LiFSI, the ether solvent is ethylene glycol dimethyl ether and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE), the volume ratio of ethylene glycol dimethyl ether and HFE in the ether electrolyte is 1:1, and the electrolyte salt concentration is approximately 1 mol·L -1 .

[0059] The specific preparation method includes the following steps, which can be carried out in an argon-filled glove box: Step S1, weigh 0.001 mol Li(FSO 2 ) 2 N salt.

[0060] Step S2: Li(FSO 2 ) 2 The N salt was dissolved in 0.5 mL of ethylene glycol dimethyl ether and 0.5 mL of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, and the mixture was mixed uniformly to obtain an electrolyte.

[0061] 1. The electrolytes obtained in Example 1 and Comparative Examples 1-2 were subjected to the following tests: (I) Self-extinguishing test: The same mass of the electrolyte prepared in Example 1 and Comparative Examples 1-2 was placed in the positive electrode shell, and an ignition test was performed using an igniter to test the self-extinguishing time of the electrolyte. The self-extinguishing time refers to the time it takes for the electrolyte or battery to extinguish itself after being affected by an external heat source such as ignition or high temperature, which reflects the safety of the electrolyte. The test results are shown in Figure 2 .

[0062] (II) Negative electrode flame retardancy test: A certain amount of the electrolyte prepared in Example 1 and Comparative Examples 1-2 and the lithium graphite negative electrode plate are placed in the positive electrode shell, and an ignition test is performed using an igniter to test the self-extinguishing time. The test results are shown in Figure 3 .

[0063] (III) The electrical performance test conditions are as follows: the electrolyte prepared in Example 1 and Comparative Example 1 is used as the electrolyte, and the electrolyte addition amount is 40~100 μL; lithium iron phosphate is used as the positive electrode material and graphite is used as the negative electrode material to prepare a graphite||lithium iron phosphate full battery.

[0064] The battery prepared above was subjected to a cycle performance test under the following conditions: at 25°C, the voltage range was 2.4V~4.2V, the charge and discharge rate was 0.5C, and the battery charge and discharge specific capacity and coulomb efficiency were measured. The results are as follows: Figure 4 shown.

[0065] The above results show: like Figure 2 As shown, compared with the conventional carbonate-based electrolyte and ether solvent in Comparative Examples 1-2, the electrolyte of the perchlorinated solvent in Example 1 is more difficult to ignite, and the self-extinguishing time is 0 s·g -1 , while the self-extinguishing time of comparative example 1 is 50s·g -1 The self-extinguishing time of comparative example 2 is 62s·g -1 This indicates that the electrolyte of the perchlorinated solvent in Example 1 has higher flame retardancy, which helps to reduce the safety hazard when the battery overheats.

[0066] like Figure 3 As shown, when the lithium-ion graphite negative electrode is added to the ignition test, compared with Comparative Examples 1-2, the electrolyte of the perchlorinated solvent in Example 1 is difficult to ignite, and the self-extinguishing time is 0 s·g -1 , while the self-extinguishing time of comparative example 1 is 65s·g -1 The self-extinguishing time of comparative example 2 is 86s·g -1 This indicates that the perchlorinated solvent electrolyte in Example 1 has high flame retardancy and can also play an effective flame retardant effect when ignited together with the negative electrode.

[0067] like Figure 4 As shown, in the cycle test of the battery prepared by the electrolyte of Example 1 and Comparative Example 1, the specific capacity and coulombic efficiency of Example 1 are better than those of Comparative Example 1, and the battery of Example 1 can be stably cycled for more than 1000 cycles, which indicates that the electrolyte of perchlorinated solvent has better cycle stability.

[0068] Therefore, the solvent of the perchlorinated solvent electrolyte provided in Examples 1-3 of the present application is composed of chlorinated ethers and chlorinated carbonates, and has the characteristics of low volatility and high flame retardancy. The electrolyte not only has good safety, but also has good electrochemical properties, which can ensure the safety and stable cycle of the battery.

[0069] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An electrolyte of a perchlorinated solvent, characterized in that: include: Electrolyte salt and perchlorinated solvent, wherein the perchlorinated solvent is composed of chlorinated ether and chlorinated carbonate.

2. The electrolyte of the perchlorinated solvent according to claim 1, characterized in that The chloroether is a linear chloroether.

3. The electrolyte of the perchlorinated solvent according to claim 2, characterized in that The chloroether has a general structural formula as shown in formula (I): （Ⅰ）， Wherein, R1 and R2 are independently selected from one of chlorine and chloroalkyl, and n is an integer of 1 to 10.

4. The electrolyte of the perchlorinated solvent according to claim 1, characterized in that The chlorocarbonate is a cyclic chlorocarbonate.

5. The electrolyte of perchlorinated solvent according to claim 4, characterized in that The chlorocarbonate has a general structural formula as shown in formula (II): （Ⅱ）， Wherein, R3 and R4 are independently selected from chlorine and chloroalkyl, and n is an integer of 1 to 10.

6. The electrolyte of perchlorinated solvent according to claim 1, characterized in that The chloroether includes at least one of bis[2-(2-chloroethoxy)ethyl]ether, 1,2-bis(2-chloroethoxy)ethane, chloromethyl ether, chloroethyl ether, chloropropyl ether and chlorobutyl ether.

7. The electrolyte of perchlorinated solvent according to claim 1, characterized in that The chlorinated carbonate includes at least one of chloroethylene carbonate and dichloroethylene carbonate.

8. The electrolyte of perchlorinated solvent according to claim 1, characterized in that In the perchlorinated solvent, the volume ratio of the chlorinated ether to the chlorinated carbonate is 1:(0.1-1).

9. The electrolyte of perchlorinated solvent according to claim 1, characterized in that The electrolyte salt is a lithium salt, and the lithium salt includes at least one of Li2SO4, LiClO4, LiNO3, LiCl, LiCF3SO3, LiPF6, Li(FSO2)2N, LiBF4, LiDFOB, Li(CF3CF2SO2)2N and Li(CF3SO2)2N.

10. An electrochemical device, characterized in that: It comprises a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte, wherein the separator is arranged between the positive electrode sheet and the negative electrode sheet, wherein the electrolyte is the electrolyte of the perchlorinated solvent as claimed in any one of claims 1 to 9.

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