Non-aqueous electrolyte, electrochemical device comprising same, and electronic device
Patent Information
- Application Number
- PCT/CN2025/083848
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-03-20
- Publication Date
- 2026-09-24
Smart Images
Figure CN2025083848_24092026_PF_FP_ABST
Abstract
Description
Non-aqueous electrolytes and electrochemical and electronic devices containing such non-aqueous electrolytes. Technical Field
[0001] This application belongs to the field of battery technology, and particularly relates to the field of lithium-ion battery technology, specifically to a non-aqueous electrolyte and an electrochemical device and electronic device containing the non-aqueous electrolyte. Background Technology
[0002] Electrochemical devices (e.g., lithium-ion batteries, sodium-ion batteries) have broad application prospects in energy storage, consumer electronics, and electric vehicles. However, factors such as cycle life, low-temperature discharge, and self-discharge often affect the stability and user experience of electrochemical devices, thus placing higher demands on them. For example, electric vehicles are expected to have a lifespan comparable to that of gasoline vehicles (8-10 years), and cold winters in northern regions require low-temperature discharge performance; energy storage devices need to have low long-term self-discharge and a long-term reliable lifespan. All of these factors place high demands on the cycle life, low-temperature discharge, and self-discharge performance of electrochemical devices. Summary of the Invention
[0003] The purpose of this application is to provide a non-aqueous electrolyte and an electrochemical and electronic device comprising the non-aqueous electrolyte, so as to improve the self-discharge performance and low-temperature cycling performance of the electrochemical device. The specific solution is as follows:
[0004] According to a first aspect of this application, this application provides a non-aqueous electrolyte comprising a compound of formula I and a dinitrile compound;
[0005] The general formula of the dinitrile compound is: NC-(CR 21 R 22 )nN, where n is an integer selected from 2 to 10, R 21 R 22 Each is independently selected from any one of hydrogen (H), halogen atoms, and methyl (CH3);
[0006] In Equation I, R 11 R 12 R 13 R 14 R 15 Each is independently selected from any one of hydrogen, fluorine atom, unsubstituted or fluorinated C1-C4 alkyl, unsubstituted or fluorinated C2-C4 alkenyl, unsubstituted or fluorinated C3-C4 alkynyl, and unsubstituted or fluorinated phenyl.
[0007] Based on the total mass of the non-aqueous electrolyte, the mass percentage of the compound of formula I is a, and the mass percentage of the dinitrile compound is b, wherein a satisfies: 0.001% to 0.8%, and b satisfies: 0.01% to 7%.
[0008] Firstly, while the compound of formula I can form a stable protective film on the electrode surface, increasing the cycle life of the electrochemical device, the poor ionic conductivity of the film-forming component affects the low-temperature performance of the electrochemical device. Simultaneously, the compound of formula I contains nitrogen (N), which has a lone pair of electrons that can complex with metal ions, dissolve in the electrolyte, and then be reduced and deposited at the negative electrode, causing a micro-short circuit and increasing the self-discharge of the electrochemical device. This application has found that combining a dinitrile compound with the compound of formula I in the electrolyte, where the dinitrile compound contains nitrile (-CN) groups, which have a stronger adsorption effect on metal ions, and form a precipitate after adsorption and complexation with metal ions, reduces the presence of metal ions in the electrolyte, further preventing metal ions from depositing at the negative electrode. Reduction deposition significantly improves the self-discharge and cycle performance of the electrochemical device. Simultaneously, the content of compound I in the electrolyte further affects film formation. Too low a content results in uneven film formation and insufficient protection of the electrode interface; too high a content prevents further improvement in self-discharge performance and results in an excessively thick film with high impedance, further impacting cycle performance. The content of dinitrile compounds in the electrolyte further affects metal ion deposition, electrolyte viscosity, and interfacial impedance. Too low a content is insufficient for complete deposition of dissolved metal ions in the electrochemical device; too high a content increases electrolyte viscosity and electrode interfacial impedance, also affecting cycle performance. Therefore, in the technical solution provided in this application, controlling the mass percentage 'a' of compound I and the mass percentage 'b' of dinitrile compounds within the aforementioned ranges allows the electrochemical device to achieve better improvements in self-discharge and cycle performance.
[0009] In some embodiments of this application, 'a' satisfies the condition: 0.01% to 0.8%. Further adjusting the mass percentage 'a' of the compound of formula I within the above range can further improve the self-discharge performance and cycle performance of the electrochemical device.
[0010] In some embodiments of this application, b satisfies: 0.05%–7%; preferably, b satisfies: 0.8%–7%; preferably, b satisfies: 3%–5%. The content of the dinitrile compound in the electrolyte further affects the deposition of metal ions, as well as the viscosity and interfacial impedance of the electrolyte. If the content of the dinitrile compound in the electrolyte is too low, it is insufficient to ensure complete deposition of the dissolved metal ions in the electrochemical device; if the content of the dinitrile compound is too high, it will further increase the viscosity of the electrolyte, increase the electrode interfacial impedance, and also affect the cycle performance. In the technical solution provided in this application, when the amount of dinitrile compound is further controlled within the above-mentioned range, the self-discharge of the electrochemical device can be further improved while improving the cycle performance.
[0011] In some embodiments of this application, the compound of formula I includes at least one of the following compounds (formula I-1) to (formula I-20):
[0012] In the technical solution provided in this application, when the compound of formula I is selected from at least one of the above compounds, a better self-discharge effect can be achieved.
[0013] In some embodiments of this application, the dinitrile compound includes at least one selected from butadionitrile, glutaronitrile, adiponitrile, heptacyanide, caprylylnitrile, sebacic acid, anonadionitrile, or 2-methylglutaronitrile. In the technical solutions provided in this application, when the dinitrile compound is selected from at least one of the above compounds, better self-discharge and improved cycle performance can be achieved.
[0014] In some embodiments of this application, the non-aqueous electrolyte further comprises difluorophosphate (MPO2F2), which includes at least one of lithium difluorophosphate (LiPO2F2), sodium difluorophosphate (NaPO2F2), potassium difluorophosphate (KPO2F2), or cesium difluorophosphate (CsPO2F2). Based on the total mass of the non-aqueous electrolyte, the mass percentage of difluorophosphate (MPO2F2) is c, where c satisfies 0.001% to 1%. This application has found that when difluorophosphate (MPO2F2) is further added to an electrolyte containing both a compound of formula I and a dinitrile compound, the difluorophosphate (MPO2F2) has a special POF structure, which can form a protective film rich in M ions of POF inorganic components on the electrode surface. This protective film has good ionic conductivity, which can increase the ionic conductivity of the protective film on the electrode surface and reduce Li... +The resistance to penetration through the protective film, and the fact that the inorganic components formed by difluorophosphate (MPO2F2) are generally distributed in an island-like pattern, combined with the protective film formed by compound I, increases the density of the protective film on the electrode surface and improves ionic conductivity. This ensures improved self-discharge performance of the electrochemical device while further guaranteeing its cycle performance and low-temperature discharge performance. Simultaneously, the content of difluorophosphate (MPO2F2) further affects the low-temperature performance of the electrochemical device. Too low a content is insufficient to form a adequate interfacial protective film, while too high a content may prevent dissolution or cause a decrease in electrolyte conductivity, thus affecting the low-temperature discharge performance of the electrochemical device. Therefore, in the further solution provided in this application, by further controlling the amount of difluorophosphate (MPO2F2) within the aforementioned range, it is possible to improve the self-discharge of the electrochemical device while significantly improving its cycle performance and low-temperature discharge performance.
[0015] In some embodiments of this application, c satisfies: 0.01% to 1%; preferably, c satisfies: 0.5% to 1%. The content of difluorophosphate (MPO2F2) further affects the low-temperature performance of the electrochemical device. If the content of difluorophosphate (MPO2F2) is too low, it is insufficient to form a sufficient interfacial protective film; if the content of difluorophosphate (MPO2F2) is too high, it may not dissolve or cause a decrease in the conductivity of the electrolyte, thereby affecting the low-temperature discharge performance of the electrochemical device. In a further solution provided in this application, when the amount of difluorophosphate (MPO2F2) is further controlled within the above-mentioned range, it is possible to improve the self-discharge of the electrochemical device while further improving the cycle performance and low-temperature discharge performance of the electrochemical device.
[0016] In some embodiments of this application, the non-aqueous electrolyte further comprises a compound of formula IV;
[0017] In Equation IV, R 41 and R 42Each compound is independently selected from any one of methyl, ethyl, n-propyl, isopropyl, fluorinated methyl, fluorinated ethyl, fluorinated n-propyl, or fluorinated isopropyl; based on the total mass of the non-aqueous electrolyte, the mass percentage of the compound of formula IV is 0.001% to 0.8%. Compound of formula IV is a decomposition product of the electrolyte. This application has found that, in a further embodiment provided in this application, adding compound of formula IV to the electrolyte can further suppress the occurrence of side reactions in the electrolyte. The content of compound of formula IV affects the degree of side reactions; for example, if the content of compound of formula IV is too high, it will further increase side reactions due to its own decomposition. Further controlling the amount of compound of formula IV in the electrolyte within the above-mentioned range can further reduce side reactions in the electrolyte, thereby further improving the self-discharge performance of the electrochemical device while significantly improving the cycle and low-temperature discharge performance of the electrochemical device.
[0018] In some embodiments of this application, the mass percentage of the compound of formula IV is 0.1% to 0.8%. Further adjusting the mass percentage of the compound of formula IV within the above range can improve the self-discharge performance of the electrochemical device, while also further improving the cycle performance and low-temperature discharge performance of the electrochemical device.
[0019] In some embodiments of this application, the Formula IV compound includes at least one of the following (Formula IV-1) to (Formula IV-6) compounds:
[0020] In a further embodiment of this application, when the compound of formula IV is selected from at least one of the above compounds, the self-discharge effect of the electrochemical device can be improved, while the cycling and low-temperature discharge performance of the electrochemical device can be further improved.
[0021] According to a second aspect of this application, an electrochemical device is also provided, comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte as described in any of the first aspects of this application. The electrochemical device using the above-described electrolyte system exhibits excellent low-temperature discharge, cycling, and self-discharge performance.
[0022] In some embodiments of this application, the non-aqueous electrolyte content (w) of the electrochemical device is 1.5–4.5 g / Ah; preferably, the non-aqueous electrolyte content (w) of the electrochemical device is 2.0–4.0 g / Ah. Too low a non-aqueous electrolyte content (liquid content) will lead to functional failure of the electrochemical device after long-term use (such as short cycle life, inability to charge and discharge, etc.), while too high a content will lead to excessive electrolyte side reactions (such as gas expansion) and increased costs. Controlling an appropriate electrolyte content can fully meet the long-term service life requirements of the electrochemical device.
[0023] According to a third aspect of this application, this application also provides an electronic device, said electronic device including any of the electrochemical devices described in the second aspect of this application. Detailed Implementation
[0024] The technical solutions of this application are further illustrated below through specific embodiments. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.
[0025] I. Electrolyte
[0026] According to a first aspect of this application, this application provides a non-aqueous electrolyte comprising a compound of formula I and a dinitrile compound;
[0027] The general formula of the dinitrile compound is: NC-(CR 21 R 22 )n-NC, where n is an integer selected from 2 to 10, R 21 R 22 Each is independently selected from any one of hydrogen (H), halogen atoms, and methyl (CH3);
[0028] In Equation I, R 11 R 12 R 13 R 14 R 15 Each is independently selected from at least one of hydrogen (H), fluorine atom (F), unsubstituted or fluorinated C1-C4 alkyl, unsubstituted or fluorinated C2-C4 alkenyl, unsubstituted or fluorinated C3-C4 alkynyl, and unsubstituted or fluorinated phenyl.
[0029] Based on the total mass of the non-aqueous electrolyte, the mass percentage of the compound of formula I is a, and the mass percentage of the dinitrile compound is b, wherein a satisfies: 0.001% to 0.8%, and b satisfies: 0.01% to 7%.
[0030] Specifically, the "unsubstituted or fluorinated C1-C4 alkyl group" includes: a C1-C4 alkyl group or a group in which the H in a C1-C4 alkyl group is monosubstituted or polysubstituted with fluorine; the "unsubstituted or fluorinated C2-C4 alkenyl group" includes: a C2-C4 alkenyl group or a group in which the H in a C2-C4 alkenyl group is monosubstituted or polysubstituted with fluorine; the "unsubstituted or fluorinated C3-C4 alkynyl group" includes a C3-C4 alkynyl group or a group in which the H in a C3-C4 alkynyl group is monosubstituted or polysubstituted with fluorine; the "unsubstituted or fluorinated phenyl group" includes a phenyl group or a group in which the H in a phenyl group is monosubstituted or polysubstituted with fluorine. The "halogen atom" includes, but is not limited to, any one of: fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).
[0031] Specifically, in some embodiments of this application, based on the total mass of the non-aqueous electrolyte, the mass percentage 'a' of the compound of Formula I can be 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, or a range of any two of the above values. Specifically, in some embodiments of this application, based on the total mass of the non-aqueous electrolyte, the mass percentage b of the dinitrile compound can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1 0.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, 5.5%, 6%, 6.5%, 7%, or a range consisting of any two of the above values.
[0032] Firstly, while the compound of formula I can form a stable protective film on the electrode surface, increasing the cycle life of the electrochemical device, the poor ionic conductivity of the film-forming components affects the low-temperature performance of the electrochemical device. Simultaneously, the compound of formula I contains nitrogen (N), which has lone pairs of electrons that can complex with metal ions, dissolve in the electrolyte, and then be reduced and deposited at the negative electrode, causing micro-short circuits and increasing the self-discharge of the electrochemical device. This application has found that combining a dinitrile compound with the compound of formula I in the electrolyte, where the dinitrile compound contains nitrile (-CN) groups, strengthens the adsorption of metal ions and forms precipitates after adsorption and complexation, reducing the presence of metal ions in the electrolyte and further preventing metal ions from depositing at the negative electrode. The reduction deposition significantly improves the self-discharge performance and low-temperature cycling performance of the electrochemical device. Simultaneously, the content of compound I in the electrolyte further affects the film formation effect. If the content of compound I is too low, uniform film formation is impossible, failing to adequately protect the electrode interface. If the content of compound I is too high, self-discharge performance cannot be further improved, and the film will be too thick, resulting in high impedance and further affecting cycling performance. The content of dinitrile compound in the electrolyte further affects the deposition of metal ions, as well as the viscosity and interfacial impedance of the electrolyte. If the content of dinitrile compound in the electrolyte is too low, it is insufficient to completely deposit the dissolved metal ions in the electrochemical device. If the content of dinitrile compound is too high, it will further increase the electrolyte viscosity and electrode interfacial impedance, also affecting cycling performance. Therefore, in the technical solution provided in this application, controlling the mass ratio 'a' of compound I and the mass ratio 'b' of dinitrile compound within the above-mentioned ranges can achieve better improvement in the self-discharge performance and cycling performance of the electrochemical device.
[0033] In some embodiments of this application, 'a' satisfies the condition: 0.01% to 0.8%. Further adjusting the mass percentage 'a' of the compound of formula I within the above range can further improve the self-discharge performance and cycle performance of the electrochemical device.
[0034] In some embodiments of this application, b satisfies: 0.05%–7%; preferably, b satisfies: 0.8%–7%; preferably, b satisfies: 3%–5%. The content of the dinitrile compound in the electrolyte further affects the deposition of metal ions, as well as the viscosity and interfacial impedance of the electrolyte. If the content of the dinitrile compound in the electrolyte is too low, it is insufficient to ensure complete deposition of the dissolved metal ions in the electrochemical device; if the content of the dinitrile compound is too high, it will further increase the viscosity of the electrolyte, increase the electrode interfacial impedance, and also affect the cycle performance. In the technical solution provided in this application, when the amount of dinitrile compound is further controlled within the above-mentioned range, the self-discharge of the electrochemical device can be further improved while improving the cycle performance.
[0035] In some embodiments of this application, the compound of formula I includes at least one of the following compounds (formula I-1) to (formula I-20):
[0036] In the technical solution provided in this application, when the compound of formula I is selected from at least one of the above compounds, a better self-discharge effect can be achieved.
[0037] In some embodiments of this application, the dinitrile compound includes at least one selected from butadionitrile, glutaronitrile, adiponitrile, heptacyanide, caprylylnitrile, sebacic acid, anonadionitrile, or 2-methylglutaronitrile. In the technical solutions provided in this application, when the dinitrile compound is selected from at least one of the above compounds, better self-discharge and improved cycle performance can be achieved.
[0038] In some embodiments of this application, the non-aqueous electrolyte further comprises difluorophosphate (MPO2F2), wherein the difluorophosphate (MPO2F2) includes at least one of lithium difluorophosphate (LiPO2F2), sodium difluorophosphate (NaPO2F2), potassium difluorophosphate (KPO2F2), or cesium difluorophosphate (CsPO2F2); based on the total mass of the non-aqueous electrolyte, the mass percentage of the difluorophosphate (MPO2F2) is c, where c satisfies: 0.001% to 1%.
[0039] Specifically, in some embodiments of this application, based on the total mass of the non-aqueous electrolyte, the mass percentage of the difluorophosphate (MPO2F2) is c, where c satisfies 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or a range consisting of any two of the above values.
[0040] This application has discovered that when difluorophosphate (MPO2F2) is further added to an electrolyte containing both a compound of formula I and a dinitrile compound, the difluorophosphate (MPO2F2) has a special POF structure, which can form a protective film rich in M ions and inorganic POF components on the electrode surface. This protective film has good ionic conductivity, which can increase the ionic conductivity of the protective film on the electrode surface and reduce Li... +The resistance to penetration through the protective film, and the fact that the inorganic components formed by difluorophosphate (MPO2F2) are generally distributed in an island-like pattern, combined with the protective film formed by compound I, increases the density of the protective film on the electrode surface and improves ionic conductivity. This ensures improved self-discharge performance of the electrochemical device while further guaranteeing its cycle performance and low-temperature discharge performance. Simultaneously, the content of difluorophosphate (MPO2F2) further affects the low-temperature performance of the electrochemical device. Too low a content is insufficient to form a adequate interfacial protective film, while too high a content may prevent dissolution or cause a decrease in electrolyte conductivity, thus affecting the low-temperature discharge performance of the electrochemical device. Therefore, in the further solution provided in this application, by further controlling the amount of difluorophosphate (MPO2F2) within the aforementioned range, it is possible to improve the self-discharge of the electrochemical device while significantly improving its cycle performance and low-temperature discharge performance.
[0041] In some embodiments of this application, c satisfies: 0.01% to 1%; more preferably, c satisfies: 0.5% to 1%. The content of difluorophosphate (MPO2F2) further affects the low-temperature performance of the electrochemical device. If the content of difluorophosphate (MPO2F2) is too low, it is insufficient to form a sufficient interfacial protective film; if the content of difluorophosphate (MPO2F2) is too high, it may not dissolve or cause a decrease in the conductivity of the electrolyte, thereby affecting the low-temperature discharge performance of the electrochemical device. In a further solution provided in this application, when the amount of difluorophosphate (MPO2F2) is further controlled within the above-mentioned range, it is possible to improve the self-discharge of the electrochemical device while further improving the cycle performance and low-temperature discharge performance of the electrochemical device.
[0042] In some embodiments of this application, the non-aqueous electrolyte further comprises a compound of formula IV;
[0043] In Equation IV, R 41 and R 42 Each compound is independently selected from any one of methyl, ethyl, n-propyl, isopropyl, fluorinated methyl, fluorinated ethyl, fluorinated n-propyl, or fluorinated isopropyl; the mass percentage of the compound of formula IV is 0.001% to 0.8% based on the total mass of the non-aqueous electrolyte.
[0044] Specifically, fluorinated methyl refers to methyl with hydrogen mono- or poly-substituted fluorine; fluorinated ethyl refers to ethyl with hydrogen mono- or poly-substituted fluorine; fluorinated n-propyl refers to n-propyl with hydrogen mono- or poly-substituted fluorine; and fluorinated isopropyl refers to isopropyl with hydrogen mono- or poly-substituted fluorine. Specifically, the mass percentage of the compound of formula IV can be 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, or a range consisting of any two of the above values.
[0045] Compound IV is a decomposition product of the electrolyte. This application has found that, in a further embodiment provided in this application, adding compound IV to the electrolyte can further suppress side reactions in the electrolyte. The content of compound IV affects the degree of side reactions; for example, excessive content of compound IV will further increase side reactions due to its own decomposition. Further controlling the amount of compound IV in the electrolyte within the aforementioned range can further reduce side reactions in the electrolyte, thereby further improving the self-discharge performance of the electrochemical device while significantly improving its cycle and low-temperature discharge performance.
[0046] In some embodiments of this application, the mass percentage of the compound of formula IV is 0.1% to 0.8%. By controlling the mass percentage of the compound of formula IV within the above range, it is possible to improve the self-discharge performance of the electrochemical device, while further improving the cycle performance and low-temperature discharge performance of the electrochemical device.
[0047] In some embodiments of this application, the Formula IV compound includes at least one of the following (Formula IV-1) to (Formula IV-6) compounds:
[0048] In a further embodiment of this application, when the compound of formula IV is selected from at least one of the above compounds, the self-discharge effect of the electrochemical device can be further improved, while the cycling and low-temperature discharge performance of the electrochemical device can be further improved.
[0049] In some embodiments of this application, the electrolyte provided may also contain other components, including but not limited to at least one of carbonate compounds, carboxylic acid ester compounds, ether compounds, or other organic solvents. The aforementioned carbonate compounds include, but are not limited to, at least one of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, propylene carbonate, butenyl carbonate, or di-2,2,2-trifluoroethyl carbonate. The aforementioned carboxylic acid ester compounds include, but are not limited to, at least one of methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, γ-butyrolactone, 2,2-difluoroethyl acetate, valproic acid lactone, butyrolactone, ethyl 2-fluoroacetate, ethyl 2,2-difluoroacetate, or ethyl trifluoroacetate. The aforementioned ether compounds include, but are not limited to, at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dibutyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, or bis(2,2,2-trifluoroethyl) ether. Other organic solvents may include, but are not limited to, at least one of dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolium ketone, N-methyl-2-pyrrolidone, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, or trioctyl phosphate.
[0050] In some embodiments of this application, the electrolyte provided may further include lithium salts as the electrolyte. The lithium salts in the electrolyte include, but are not limited to: lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium hexafluorophosphate (LiPF6), lithium hexafluoroantimonyate (LiSbF6), lithium fluorosulfonate (LiSO3F), lithium bis(fluorosulfonyl)imide (LiN(FSO2)2), lithium trifluoromethanesulfonate (LiCF3SO3), lithium di(trifluoromethanesulfonyl)imide (LiN(FSO2)(CF3SO2)), lithium trifluoromethanesulfonylimide (LiN(CF3SO2)2), lithium bis(trifluoromethanesulfonyl)imide (LiN(C2F5SO2)2), lithium bis(oxalate)borate, lithium tri(oxalate)phosphate, lithium difluorobis(oxalate)phosphate, or lithium tetrafluoro(oxalate)phosphate. Furthermore, one of the above lithium salts may be used alone, or two or more may be used simultaneously. In some embodiments, the lithium salt includes LiPF6. In some embodiments, the mass content of lithium salt in the electrolyte is 10% to 20% based on the total mass of the electrolyte. Specifically, the mass content of lithium salt in the electrolyte is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or a range of any two of the above values, based on the total mass of the electrolyte.
[0051] In some embodiments of this application, the preparation method of the electrolyte provided in this application is not limited and can be prepared in accordance with conventional electrolyte preparation methods. In some embodiments, the electrolyte of this application can be prepared by mixing the components.
[0052] II. Electrochemical Device
[0053] According to a second aspect of this application, an electrochemical device is also provided, comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte as described in any of the first aspects of this application. The electrochemical device using the above-described electrolyte system exhibits excellent low-temperature discharge, cycling, and self-discharge performance.
[0054] In some embodiments of this application, the electrochemical device includes, but is not limited to, all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In some embodiments of this application, the electrochemical device is a lithium secondary battery. In some embodiments of this application, the lithium secondary battery includes, but is not limited to, lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries. In some embodiments of this application, the electrochemical device can also be a negative electrode-free battery system.
[0055] In some embodiments of this application, the non-aqueous electrolyte content (w) of the electrochemical device is 1.5–4.5 g / Ah. Specifically, the non-aqueous electrolyte content (w) of the electrochemical device can be 1.5 g / Ah, 1.6 g / Ah, 1.7 g / Ah, 1.8 g / Ah, 1.9 g / Ah, 2.0 g / Ah, 2.1 g / Ah, 2.2 g / Ah, 2.3 g / Ah, 2.4 g / Ah, 2.5 g / Ah, 2.6 g / Ah, 2.7 g / Ah, 2.8 g / Ah, or 2.9 g / Ah. The concentrations of the non-aqueous electrolyte in the electrochemical device are 3.0 g / Ah, 3.1 g / Ah, 3.2 g / Ah, 3.3 g / Ah, 3.4 g / Ah, 3.5 g / Ah, 3.6 g / Ah, 3.7 g / Ah, 3.8 g / Ah, 3.9 g / Ah, 4.0 g / Ah, 4.1 g / Ah, 4.2 g / Ah, 4.3 g / Ah, 4.4 g / Ah, 4.5 g / Ah, or any two of the above values. Preferably, the amount (w) of the non-aqueous electrolyte in the electrochemical device is 2.0–4.0 g / Ah or any two of the above values. If the amount of non-aqueous electrolyte in an electrochemical device is too low, it will lead to functional failure after long-term use (such as short cycle life, inability to charge and discharge, etc.). If the amount of electrolyte is too high, it will lead to excessive electrolyte side reactions (such as gas expansion) and increase costs. Controlling the appropriate amount of electrolyte can fully meet the long-term service life requirements of the electrochemical device.
[0056] 1. Positive electrode
[0057] In some embodiments of this application, the positive electrode includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The specific type of positive electrode active material in the positive electrode active material layer is not specifically limited and can be selected according to requirements. In some embodiments of this application, the positive electrode active material includes a lithium transition metal composite oxide. In some embodiments, the positive electrode active material is selected from at least one of the following: lithium cobalt oxide, lithium nickel manganese cobalt ternary materials, lithium manganese oxide, lithium nickel manganese oxide (or lithium iron phosphate).
[0058] In some embodiments of this application, the positive electrode active material layer further includes an adhesive. In some embodiments, the adhesive includes, but is not limited to, polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, and nylon, etc.
[0059] In some embodiments of this application, the positive electrode active material layer further includes a conductive agent. In some embodiments, the conductive agent may include any conductive material, as long as it does not cause a chemical change. Non-limiting examples of conductive materials include carbon-based materials (e.g., carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (e.g., metal powder, metal fiber, etc., including, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives), and mixtures thereof.
[0060] In some embodiments of this application, the positive current collector is a metal, such as aluminum foil.
[0061] In some embodiments of this application, the structure of the positive electrode is a positive electrode structure known in the art that can be used in electrochemical devices.
[0062] In some embodiments of this application, the method for preparing the positive electrode is a well-known method in the art for preparing positive electrodes for electrochemical devices. For example, the positive electrode can be obtained by mixing a positive electrode active material, a conductive agent, and a binder in a solvent to prepare a positive electrode active material slurry, coating the positive electrode active material slurry onto a positive electrode current collector, drying, and cold pressing to form a positive electrode active material layer. In some embodiments, the solvent may include water, N-methylpyrrolidone, etc., but is not limited thereto.
[0063] 2. Negative electrode
[0064] In some embodiments of this application, the negative electrode includes a negative electrode current collector and a negative polar material layer located on at least one surface of the negative electrode current collector. The negative electrode active material layer includes a negative electrode active material, which is any material capable of electrochemically adsorbing and releasing metal ions such as lithium ions. In some embodiments of this application, the negative electrode active material includes carbonaceous materials (graphite), silicon materials, hard carbon materials, or lithium metal materials. In some embodiments of this application, the negative electrode active material includes one or more of the above-mentioned materials.
[0065] In some embodiments of this application, the negative electrode active material layer further includes a conductive agent. In some embodiments, the conductive agent includes, but is not limited to: carbon-based materials, such as carbon black, acetylene black, Ketjen black, carbon fiber, etc.; metal-based materials, such as metal powders or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers, such as polyphenylene derivatives, etc.; or mixtures thereof.
[0066] In some embodiments of this application, the negative electrode active material layer further includes a thickener. The thickener may be selected from sodium carboxymethyl cellulose (CMC-Na), styrene-butadiene rubber (SBR), and polyvinylidene fluoride (PVDF).
[0067] In some embodiments of this application, the negative electrode active material layer further includes an adhesive, which may include various adhesive polymers such as polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.
[0068] In some embodiments of this application, the negative electrode current collector includes, but is not limited to: copper foil, aluminum foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and any combination thereof. In some embodiments, the negative electrode current collector is copper foil.
[0069] In some embodiments of this application, the structure of the negative electrode can be a negative electrode structure known in the art that can be used in electrochemical devices.
[0070] In some embodiments of this application, the method for preparing the negative electrode is a method known in the art for preparing negative electrodes that can be used in electrochemical devices. Exemplarily, the negative electrode can be obtained by mixing a negative electrode active material, a conductive agent, and a binder in a solvent, and heating a thickener as needed to prepare a negative electrode active material slurry, coating the negative electrode active material slurry onto a negative electrode current collector, drying, and cold pressing to form a negative electrode active material layer. In some embodiments, the solvent may include, but is not limited to, water and N-methylpyrrolidone.
[0071] 3. Separating membrane
[0072] In some embodiments of this application, the electrochemical device further includes a separating membrane. In some embodiments, the separating membrane includes a substrate layer, which is a nonwoven fabric, membrane, or composite membrane with a porous structure. The material of the substrate layer may be selected from at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyimide. Specifically, the material of the substrate layer may be selected from at least one of polypropylene porous membrane, polyethylene porous membrane, polypropylene nonwoven fabric, polyethylene nonwoven fabric, or polypropylene-polyethylene-polypropylene porous composite membrane. At least one surface of the substrate layer is provided with a surface treatment layer. The surface treatment layer may be a polymer layer, an inorganic layer, or a layer formed by a mixture of polymers and inorganic materials. Specifically, the inorganic layer comprises inorganic particles and a binder. The inorganic particles may be selected from one or more of the following: alumina, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, or barium sulfate. The binder may be selected from one or more of the following: polyvinylidene fluoride, a polymer of polyvinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, and polyhexafluoropropylene.
[0073] In some embodiments of this application, the preparation method of the electrochemical device provided in this application is not limited and can be carried out in accordance with conventional electrochemical device preparation methods. In some embodiments, the electrochemical device of this application can be prepared by the following method: the prepared positive electrode, negative electrode and separator are stacked in sequence, with the separator positioned between the positive electrode and negative electrode to provide isolation; the electrode assembly is wound up; then adhesive tape is attached to the outermost ring of the wound layer of the electrode assembly to fix the wound structure; then the electrode assembly is placed in a packaging bag, injected with a non-aqueous electrolyte, and sealed. The electrochemical device is obtained through processes such as resting, formation, degassing, trimming, and capacity testing.
[0074] III. Electronic Devices
[0075] According to a third aspect of this application, this application also provides an electronic device, which includes the electrochemical device described in any of the second aspects of this application. In some embodiments, the electronic device of this application includes, but is not limited to: laptop computers, pen-based computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CD-ROMs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc. Furthermore, the electrochemical device provided in this application is applicable not only to the electronic devices exemplified above, but also to energy storage power stations, maritime transport vehicles, and air transport vehicles, including air transport vehicles within the atmosphere and air transport vehicles outside the atmosphere.
[0076] The following describes the implementation of this application in more detail through specific embodiments and comparative examples.
[0077] I. Battery performance testing methods:
[0078] (1) Self-discharge performance test of lithium-ion batteries
[0079] The battery was charged at a constant current of 0.5C to 4.2V at room temperature, and then charged at a constant voltage of 4.2V to a current of 0.025C. After standing for 15 minutes, it was discharged at 0.5C for 60 minutes. The battery voltage V1 at the end of the discharge was recorded. The battery was then placed at 45℃ for 24 hours, and then transferred to room temperature and placed for 24 hours. The battery voltage V2 at this time was recorded. The self-discharge performance of the battery (V / h) = (V1-V2) / 48h.
[0080] (2) Low-temperature discharge performance test of lithium-ion batteries
[0081] Place the battery in a high and low temperature chamber, set the temperature to 25℃, and let it stand for 60 minutes. First, charge the battery at a constant current of 0.5C to 4.2V, then charge it at a constant voltage of 4.2V to the cutoff current of 0.025C. Let it stand for 5 minutes, and then discharge it at 0.5C to 3.0V. Record the discharge capacity C at this point. 25 Then, it is charged at a constant current of 0.5C to 4.2V, and then charged at a constant voltage of 4.2V to the cutoff current of 0.025C. The temperature of the high and low temperature chamber is adjusted to -20℃, and it is left to stand for 60 minutes. Then, it is discharged at 0.5C to 3.0V, and the discharge capacity C is recorded at this time. -20 Then the low-temperature discharge capacity retention rate / % = (C 25 -C -20 ) / C25 *100%, evaluating the low-temperature discharge performance of lithium-ion batteries by low-temperature discharge capacity retention rate.
[0082] (3) Lithium-ion battery cycle performance test
[0083] Place the battery in a high-temperature chamber at 45°C. Then, charge the battery at a constant current of 0.5C to 4.2V, and then charge it at a constant voltage of 4.2V to the cutoff current of 0.025C. Let it rest for 5 minutes, and then discharge it at a constant current of 0.5C to 3.0V. Let it rest for 5 minutes. Repeat the above charge-discharge process 400 times. Record the discharge capacity of the nth cycle as C. n The cycle performance is calculated as follows: Cyclic performance (%) = (C 400 -C3) / C3*100%, where C 400 C1 represents the discharge capacity after the 400th cycle, and C2 represents the discharge capacity after the 3rd cycle.
[0084] (4) Test of electrolyte retention w in lithium-ion batteries:
[0085] The battery was charged at a constant current of 0.5C to 4.2V at room temperature, then charged at a constant voltage of 4.2V to the cutoff current of 0.025C. After standing for 5 minutes, it was discharged at a constant current of 0.5C to 3.0V. The discharge capacity at this step was recorded as C (Ah). The battery weight W1 (g) was then measured using an electronic balance. The battery was then disassembled, and all disassembled components (including electrodes, separator, tabs, packaging, etc.) were cleaned with dimethyl carbonate (soaked and dried). The weight of all components after cleaning was recorded as W2 (g). The electrolyte retention was then calculated as w = (W1 - W2) / C, in g / Ah.
[0086] II. Specific Implementation Examples and Comparative Examples
[0087] Example 1-1
[0088] (1) Preparation of the positive electrode
[0089] The positive electrode active material LiMn2O4, conductive agent Super P, and binder polyvinylidene fluoride were mixed in a weight ratio of 96.7:1.6:1.7 and added to N-methylpyrrolidone (NMP) solvent. The mixture was stirred evenly under vacuum to obtain a positive electrode slurry with a solid content of 72 wt%. The positive electrode slurry was uniformly coated onto the positive electrode current collector aluminum foil. The coated aluminum foil was dried at 85°C, and then cold-pressed, cut, and slit. Finally, it was dried under vacuum at 85°C for 4 hours to obtain the positive electrode.
[0090] (2) Preparation of negative electrode
[0091] Artificial graphite (anode active material), Super P (conductive agent), sodium carboxymethyl cellulose (CMC) (thickener), and styrene-butadiene rubber (SBR) (binder) were mixed in a weight ratio of 96:2:0.8:1.2. Deionized water was added, and the mixture was stirred in a vacuum mixer to obtain a cathode slurry with a solid content of 54 wt%. The cathode slurry was uniformly coated onto a copper foil current collector. The coated copper foil was dried at 85°C, then cold-pressed, cut, and slit, and finally dried under vacuum at 120°C for 12 hours to obtain the cathode.
[0092] (3) Electrolyte preparation
[0093] In a dry (water content <10ppm) argon atmosphere glove box, the solvent was mixed in a mass ratio of EC:DEC:EMC = 30:40:30. Then, fully dried lithium salt LiPF6 (1mol / kg, abbreviated as 1M) was added, dissolved, and stirred thoroughly. The compound of formula I and the dinitrile compound were then added to the electrolyte and mixed evenly to obtain the electrolyte. The mass percentage of compound of formula I was 0.001% and the mass percentage of dinitrile compound was 0.5% based on the total mass of the electrolyte.
[0094] (4) Preparation of the separating membrane
[0095] A 9μm thick polyethylene (PE) separator membrane was selected. After coating with PVDF slurry and inorganic particles (flaky boehmite and Al2O3 in a mass ratio of 70:30) and drying, the final separator membrane was obtained with a coating thickness of 3μm and a membrane porosity of 55%.
[0096] (5) Preparation of lithium-ion batteries
[0097] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a barrier between the positive and negative electrodes. Then, they are wound to obtain a bare cell. After welding the tabs, the bare cell is placed in an outer packaging foil aluminum-plastic film, and the prepared electrolyte is injected (different amounts of electrolyte can be injected depending on the situation). Then, after vacuum sealing, settling, formation (0.02C constant current charging to 3.3V, then 0.1C constant current charging to 4.0V), shaping, and capacity testing, a soft-pack lithium-ion battery is obtained.
[0098] Examples 1-2 to 1-17 and Examples 1-23 to 1-26
[0099] Except for adjusting the specific category and mass percentage a / % of Formula I compounds and the specific category and mass percentage b / % of Formula II compounds according to Table 1, the other parameters are the same as in Examples 1-1.
[0100] Examples 1-18 to Examples 1-22
[0101] Except for adjusting the specific category and mass percentage a / % of Formula I compounds and the specific category and mass percentage b / % of Formula II compounds according to Table 1, the electrolyte injection amount during battery preparation was further adjusted, and the other parameters were the same as in Examples 1-1.
[0102] Comparative Examples 1-1 to 1-5
[0103] Except for adjusting the specific category and mass percentage a / % of Formula I compounds and the specific category and mass percentage b / % of Formula II compounds according to Table 1, the other parameters are the same as in Examples 1-1.
[0104] The self-discharge performance (V / h) and cycle performance (%) of the lithium-ion batteries prepared by Examples 1-1 to 1-26 and Comparative Examples 1-1 to 1-5 were tested according to the above test methods. Simultaneously, the electrolyte content (w) in the lithium-ion batteries was also tested. The results are shown in Table 1.
[0105] Table 1 Note: "\" indicates that it was not added, and the same applies below.
[0106] According to the results shown in Table 1, and referring to Comparative Examples 1-1 to 1-3 and Examples 1-1 to 1-7, the simultaneous addition of Formula I compound and dinitrile compound to the electrolyte can significantly improve the cycle performance and self-discharge performance of the battery. Furthermore, as the content of Formula I compound increases, the self-discharge performance and cycle performance of lithium-ion batteries are gradually improved. However, when too much Formula I compound is added, the self-discharge performance and cycle performance of lithium-ion batteries decrease instead of increasing. This is because battery self-discharge is caused by both physical and chemical self-discharge. The film formation of Formula I compound on the electrode surface can reduce self-discharge caused by chemical side reactions, but the increased dissolution of metal ions will cause micro-short circuits (physical self-discharge). In other words, the amount of Formula I compound has a significant impact on the improvement effect of the corresponding performance. Meanwhile, referring to Comparative Examples 1-1 to 1-3 and Examples 1-8 to 1-17, as the content of dinitrile compound increases, the self-discharge performance of lithium-ion batteries is significantly improved. However, when too much dinitrile compound is added, the self-discharge performance and cycle performance of lithium-ion batteries decrease instead of increasing. In other words, the amount of dinitrile compound has a significant impact on the improvement effect of the corresponding performance. Therefore, by further adjusting the amounts of the Formula I compound and the dinitrile compound within the scope of this application, better self-discharge performance and cycle performance improvement can be achieved.
[0107] Examples 2-1 to 2-19
[0108] Based on the results in Table 1, the corresponding examples further investigated the effects of other components and dosages on the self-discharge, low-temperature cycling, and low-temperature discharge performance of lithium-ion batteries. Except for adjusting the specific type and mass percentage (c / %) of MPO2F2 and the specific type and mass percentage of Formula IV compounds according to Table 2, the remaining parameters of Examples 2-1 to 2-19 were the same as those of Examples 1-3.
[0109] The self-discharge performance (V / h), cycle performance (%), and low-temperature discharge performance (low-temperature discharge capacity retention, %) of the lithium-ion batteries prepared in Examples 2-1 to 2-19 were tested according to the above test methods. The results are shown in Table 2.
[0110] Table 2
[0111] Based on the results presented in Table 2, and referring to Examples 1-3 and 2-1 to 2-10, the addition of MPO2F2 to the electrolyte further improved the battery's cycle performance and enhanced its low-temperature discharge capability. As the MPO2F2 content in the electrolyte increased, the cycle performance and low-temperature discharge performance of the lithium-ion battery gradually improved. However, when excessive amounts of MPO2F2 were added, the improvement in the cycle performance and low-temperature discharge performance of the lithium-ion battery decreased instead of increasing. That is, while the addition of MPO2F2 can further improve the cycle performance and low-temperature discharge performance of the lithium-ion battery, its dosage also significantly affects the improvement effect. Further controlling the dosage of MPO2F2 within the range specified in this application can achieve good improvements in both cycle performance and low-temperature discharge performance while ensuring the improvement in battery self-discharge performance. Meanwhile, referring to Examples 1-3 and 2-11 to 2-17, the addition of compound IV to the electrolyte can further improve the battery's cycle performance. The effects of compound IV on the cycle performance and low-temperature discharge performance are observed. As the content of compound IV in the electrolyte increases, the cycle performance and low-temperature discharge performance of lithium-ion batteries are gradually improved. However, when too much compound IV is added, the improvement effect on the cycle performance and low-temperature discharge performance of lithium-ion batteries decreases instead of increasing. That is, although the addition of compound IV can further improve the cycle performance and low-temperature discharge performance of lithium-ion batteries, its dosage will also have a significant impact on the improvement effect of the corresponding performance. Further, by controlling the dosage of compound IV within the range of this application, while ensuring the improvement effect of battery self-discharge performance, a better improvement effect on cycle performance and low-temperature discharge performance can be achieved. Referring to Examples 2-18 and 2-19, when MPO2F2 and compound IV are added to the electrolyte simultaneously, the cycle performance and low-temperature discharge performance of the battery can be further improved. This may be because MPO2F2 interacts with compound IV, enhancing the stability of compound IV in the electrolyte and avoiding the side effects of instability of compound IV itself.
[0112] It is understood that this application has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the scope of this application. Furthermore, based on the teachings of this application, these features and embodiments can be modified to adapt to specific situations and materials without departing from the scope of this application. Therefore, this application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by this application.
Claims
1. A non-aqueous electrolyte, characterized in that, The non-aqueous electrolyte contains compound I and a dinitrile compound; The general formula of the dinitrile compound is: NC-(CR 21 R 22 )n-NC; n is an integer selected from 2 to 10; R 21 R 22 Each is independently selected from any one of hydrogen, halogen atoms, and methyl groups; In Equation I, R 11 R 12 R 13 R 14 R 15 Each is independently selected from any one of hydrogen, fluorine atom, unsubstituted or fluorinated C1-C4 alkyl, unsubstituted or fluorinated C2-C4 alkenyl, unsubstituted or fluorinated C3-C4 alkynyl, and unsubstituted or fluorinated phenyl. Based on the total mass of the non-aqueous electrolyte, the mass percentage of the compound of formula I is a, and the mass percentage of the dinitrile compound is b, wherein a satisfies: 0.001% to 0.8%, and b satisfies: 0.01% to 7%.
2. The non-aqueous electrolyte according to claim 1, characterized in that, a satisfies the following range: 0.01% to 0.8%.
3. The non-aqueous electrolyte according to claim 1, characterized in that, b satisfies the following range: 0.05% to 7%.
4. The non-aqueous electrolyte according to claim 1, characterized in that, b satisfies the following range: 0.8% to 7%.
5. The non-aqueous electrolyte according to claim 1, characterized in that, b satisfies: 3% to 5%.
6. The non-aqueous electrolyte according to claim 1, characterized in that, The compound of formula I includes at least one of the following compounds (formula I-1) to (formula I-20):
7. The non-aqueous electrolyte according to claim 1, characterized in that, The dinitrile compound includes at least one of butadionitrile, glutaronitrile, adiponitrile, heptaonitrile, octadionitrile, sebaonitrile, nonadionitrile, or 2-methylglutaronitrile.
8. The non-aqueous electrolyte according to claim 1, characterized in that, The non-aqueous electrolyte further comprises difluorophosphate; the difluorophosphate includes at least one of lithium difluorophosphate, sodium difluorophosphate, potassium difluorophosphate, or cesium difluorophosphate; based on the total mass of the non-aqueous electrolyte, the mass percentage of the difluorophosphate is c, where c satisfies: 0.001% to 1%.
9. The non-aqueous electrolyte according to claim 8, characterized in that, c satisfies the following range: 0.01% to 1%.
10. The non-aqueous electrolyte according to claim 8, characterized in that, c satisfies: 0.5% to 1%.
11. The non-aqueous electrolyte according to claim 1, characterized in that, The non-aqueous electrolyte also contains a compound of formula IV; In Equation IV, R 41 and R 42 Each is independently selected from any one of methyl, ethyl, n-propyl, isopropyl, fluorinated methyl, fluorinated ethyl, fluorinated n-propyl, or fluorinated isopropyl; Based on the total mass of the non-aqueous electrolyte, the mass percentage of the compound of formula IV is 0.001% to 0.8%.
12. The non-aqueous electrolyte according to claim 11, characterized in that, The mass percentage of the compound of formula IV is 0.1% to 0.8%.
13. The non-aqueous electrolyte according to claim 11, characterized in that, The compound of formula IV includes at least one of the following compounds (formula IV-1) to (formula IV-6):
14. An electrochemical device, characterized in that, The electrochemical device includes a positive electrode, a negative electrode, and a non-aqueous electrolyte as described in any one of claims 1-13.
15. The electrochemical device according to claim 14, characterized in that, The non-aqueous electrolyte content of the electrochemical device ranges from 1.5 to 4.5 g / Ah.
16. An electronic device, characterized in that, The electronic device includes the electrochemical device as described in any one of claims 14-15.