Electrolyte, battery, battery pack, electric device

Abstract

The application provides an electrolyte, a battery, a battery pack and an electric device, which comprise a flame-retardant additive; the flame-retardant additive comprises a polysiloxane additive and a phosphazene additive. The electrolyte provided by the application can simultaneously improve the flame-retardant performance and the cycle stability of the battery.

Description

Technical Field

[0001] This invention relates to an electrolyte, and more particularly to an electrolyte, a battery, a battery pack, and electrical equipment, belonging to the field of secondary batteries. Background Technology

[0002] With continuous technological advancements, the energy industry is undergoing an unprecedented revolution, and rechargeable batteries, as a reusable and environmentally friendly energy source, are attracting increasing attention. In recent years, the rapid growth of markets such as electric vehicles and mobile devices has brought unprecedented development opportunities to the rechargeable battery market.

[0003] However, batteries may experience short circuits, overcharging, or mechanical damage during use, all of which can lead to overheating and fires, causing not only economic losses but also endangering consumers' lives and health. Therefore, it is necessary not only to improve the rate performance and cycle performance of batteries but also to enhance their flame-retardant properties.

[0004] Electrolyte, as a crucial component throughout the entire battery, plays a key role in improving its flame-retardant performance. Appropriate additives can be added to the electrolyte to enhance its flame-retardant properties. Currently, commonly used electrolyte additives include phosphorus-containing additives, halogenated additives, and nitrogen-containing additives. However, using a single electrolyte additive of these types may affect the stability of the SEI film during use, leading to a decrease in battery cycle stability, and thus failing to simultaneously achieve both flame-retardant and cycle performance. Summary of the Invention

[0005] This invention provides an electrolyte comprising polysiloxane additives and phosphazene additives, which, when used in batteries, can improve battery safety while maintaining excellent cycle life.

[0006] The present invention also provides a battery comprising the above-described electrolyte, thereby exhibiting excellent cycle life and safety.

[0007] The present invention also provides a battery pack comprising the above-described battery, which thus has excellent cycle life and safety.

[0008] The present invention also provides an electrical device comprising the aforementioned battery or battery pack, which has excellent performance.

[0009] In one aspect, the present invention provides an electrolyte including flame retardant additives; the flame retardant additives include polysiloxane additives and phosphazene additives.

[0010] In the electrolyte described above, the mass ratio of the polysiloxane additive to the phosphazene additive is 1:(1-3).

[0011] In the electrolyte described above, the polysiloxane additive includes at least one of polydimethylsiloxane, polyphenylsiloxane, and epoxysilane.

[0012] And / or, the phosphazene additive is at least one of ethoxy(pentafluoro)cyclotriphosphazene, methoxypentafluorocyclotriphosphazene, hexafluorocyclotriphosphazene, and phenoxycyclotriphosphazene.

[0013] In the electrolyte described above, the end capping of at least one end of the polysiloxane additive is selected from at least one of hydroxyl, amino, epoxy, or trimethylsiloxy groups.

[0014] And / or, the molecular weight of the polysiloxane additive is less than 1000.

[0015] In the electrolyte described above, the polysiloxane additive is polydimethylsiloxane, the phosphazene additive is ethoxy(pentafluoro)cyclotriphosphazene, and the mass ratio of the polydimethylsiloxane to the ethoxy(pentafluoro)cyclotriphosphazene is 1:(1-2).

[0016] The electrolyte as described above further includes sodium salts and ester solvents;

[0017] The mass ratio of the sodium salt, the ester solvent, and the flame retardant additive is (1-20):(60-90):(1-20).

[0018] In the electrolyte as described above, the sodium salt includes at least one of sodium hexafluorophosphate, sodium perchlorate, sodium difluorosulfonate imide, and sodium bis(trifluoromethylsulfonyl)imide.

[0019] And / or, the ester solvent includes at least one of ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, and dimethyl carbonate.

[0020] In another aspect, the present invention provides a battery comprising the electrolyte as described above.

[0021] In another aspect, the present invention provides a battery pack comprising the battery as described above.

[0022] In another aspect, the present invention provides an electrical device comprising a battery as described above or a battery pack as described above.

[0023] The electrolyte provided by this invention includes polysiloxane and phosphazene additives as flame retardant additives. The simultaneous use of polysiloxane and phosphazene additives helps form a stable inorganic interface film containing Si and P on the negative electrode surface. The polysiloxane additives facilitate the formation of Si-O bonds in the SEI, combining with metal ions to form an ion-conducting layer without hindering ion extraction / intercalation. The P-containing SEI component formed by the phosphazene additives helps scavenge O and H free radicals, reducing the flammability of the electrolyte and improving the battery's flame retardancy. The synergistic effect of these two additives forms a stable SEI that also allows for ion conduction, and both contribute to scavenging O and H free radicals, reducing electrolyte flammability, and improving battery flame retardancy. Therefore, when used in batteries, these electrolyte additives not only improve cycle performance but also provide a high level of flame retardancy. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] Currently, commonly used electrolyte additives include phosphorus-containing additives, halogenated additives, and nitrogen-containing additives. However, the SEI film formed by a single electrolyte additive has limited thermal stability and cannot guarantee ion conduction between the negative electrode and the electrolyte, thus failing to improve the safety of secondary batteries while maintaining their cycle life.

[0026] In one aspect, the present invention provides an electrolyte including flame retardant additives; the flame retardant additives include polysiloxane additives and phosphazene additives.

[0027] When the electrolyte includes flame-retardant additives, such as polysiloxane and phosphazene additives, its use in batteries can significantly improve cycle life and safety. Specifically, the combination of polysiloxane and phosphazene additives helps form a stable inorganic interface film containing both Si and P on the negative electrode surface. Polysiloxane additives facilitate the formation of Si-O bonds, binding with metal ions to form an ion-conducting layer without hindering ion extraction / intercalation. The P-containing SEI component formed by phosphazene additives helps scavenge O and H free radicals, reducing the flammability of the electrolyte and improving the battery's flame retardancy. This synergistic effect not only ensures the ion conduction characteristics of the negative electrode-electrolyte interface but also suppresses side reactions at the interface. By combining these two additives, the safety performance of sodium-ion batteries is further improved without sacrificing their energy density and cycle stability.

[0028] Polysiloxane additives refer to polymers with repeating Si-O bonds as the main chain and organic groups directly attached to silicon atoms, while phosphazene additives refer to compounds containing phosphazene groups.

[0029] The mass ratio of polysiloxane additives to phosphazene additives has a significant impact on their synergistic effect.

[0030] The mass ratio of polysiloxane additives to phosphazene additives is 1:(1-3).

[0031] In detail, the mass ratio of polysiloxane additives to phosphazene additives includes, but is not limited to, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, or any combination thereof.

[0032] When the mass ratio of polysiloxane additives to phosphazene additives is within the above range, the cyclic stability of polysiloxane additives and the flame retardant effect of phosphazene additives can be fully utilized, and the resulting SEI has a certain thermal stability without hindering ion transport.

[0033] Different types of polysiloxane additives and phosphazene additives can also affect the performance. In one specific embodiment of the present invention, the polysiloxane additives include at least one of polydimethylsiloxane, polyphenylsiloxane, and epoxysilane. The above-mentioned types of polysiloxane additives exhibit excellent thermal and chemical stability, reducing the risk of decomposition under high temperatures or harsh environments and improving cycle performance.

[0034] Phosphazene additives are at least one of ethoxy(pentafluoro)cyclotriphosphazene (PFPN), methoxypentafluorocyclotriphosphazene, hexafluorocyclotriphosphazene, and phenoxycyclotriphosphazene. During combustion, phosphazene additives decompose to produce more fluorine free radicals (F·), and the phosphides readily combine with hydrogen free radicals (H·), further enhancing the flame retardant effect.

[0035] Furthermore, in one specific embodiment, the end capping of at least one end of the polysiloxane additive is selected from at least one of hydroxyl, amino, epoxy, or trimethylsiloxy groups; the aforementioned end capping improves the compatibility of the polysiloxane additive with the solvent, improves the dispersibility of the polysiloxane additive, and fully exerts its function.

[0036] In another specific embodiment, the molecular weight of the polysiloxane additive is less than 1000. When the mass-average molecular weight of the polysiloxane additive is within the above range, the electrolyte used in the battery has superior safety and cycle performance. The polysiloxane additive with the above-mentioned mass-average molecular weight has better thermal stability and chemical stability, and is more likely to form a stable sodium-rich, low-resistivity interface film, thereby improving the safety and cycle stability of the battery.

[0037] In another specific embodiment, the polysiloxane additive is polydimethylsiloxane, and the phosphazene additive is ethoxy(pentafluoro)cyclotriphosphazene (PFPN), with a mass ratio of polydimethylsiloxane to ethoxy(pentafluoro)cyclotriphosphazene of 1:(1-2).

[0038] When the above-mentioned types of polysiloxane additives and phosphazene additives are mixed in the above proportions, they exhibit superior performance. The resulting SEI has a certain degree of thermal stability but does not hinder ion transport.

[0039] It is understandable that, in order to ensure the uniformity and conductivity of the electrolyte, the electrolyte also includes sodium salt and ester solvent; the mass ratio of sodium salt, ester solvent and flame retardant additive is (1-20):(60-90):(1-20).

[0040] Sodium salts can improve conductivity, maintain charge balance in the electrolyte, enhance ion migration rates, and improve reaction kinetics. Ester solvents, on the other hand, have good solubility, effectively dissolving the electrolyte to form a homogeneous electrolyte, which facilitates ion migration and improves ionic conductivity.

[0041] In detail, this invention does not limit the specific types of sodium salts and ester solvents, and types commonly used in the art can be selected according to actual conditions. For example, the ester solvent can be at least one of cyclic carbonates and chain carbonates. In a specific embodiment of this invention, the sodium salt includes at least one of sodium hexafluorophosphate, sodium perchlorate, sodium difluorosulfonate imide, and sodium bis(trifluoromethanesulfonyl)imide; the ester solvent includes at least one of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC).

[0042] When sodium salts of the above types are selected, conductivity and cycle stability can be effectively improved. The above types of ester solvents have good solubility and stability, high temperature resistance, strong pressure resistance and can effectively transfer charge, thereby maintaining the charging and discharging process of the battery and further improving the cycle performance and safety of the battery.

[0043] Ester solvents include at least one of ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, and dimethyl carbonate.

[0044] This invention does not limit the acquisition channels of polysiloxane additives and phosphazene additives; suitable polysiloxane additives and phosphazene additives can be purchased commercially.

[0045] In another aspect, the present invention provides a battery comprising the electrolyte as described above.

[0046] Because it contains the electrolyte described above, this battery has excellent cycle life and safety.

[0047] In one specific embodiment, in addition to the electrolyte provided by this invention, the battery also includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process, active ions repeatedly insert and extract between the positive and negative electrode. The electrolyte acts as a conductor of ions between the positive and negative electrode. The separator, positioned between the positive and negative electrode, primarily prevents short circuits between the positive and negative electrodes while allowing ions to pass through.

[0048] This invention does not strictly limit the specific type of positive electrode active material in the positive electrode sheet. It can be a positive electrode active material commonly used in secondary batteries, such as at least one of NaNiO2, NaCoO2, NaMnO2, NaFePO4, Na3V2(PO4)2F3, Na3M(PO4)2 (M = Fe, Co, etc.), Na2FeP2O7, Na3SbS4, Na2S, NaTiS2, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganese oxide, nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium iron phosphate (LFP), lithium nickel manganese oxide, lithium-rich manganese-based materials, etc.

[0049] This invention does not strictly limit the negative electrode active material in the negative electrode sheet. It can be at least one of the negative electrode active materials commonly used in batteries, such as graphite, hard carbon, soft carbon, mesophase carbon microspheres, silicon-based negative electrode materials (mainly including silicon suboxide and silicon-carbon negative electrodes), and tin-based negative electrode materials (mainly including tin and tin alloys).

[0050] This invention does not strictly limit the choice of separator material. It can be a separator material commonly used in batteries, such as polypropylene separator (PP), polyethylene separator (PE), polypropylene / polyethylene double-layer composite membrane (PP / PE), polyimide electrospun separator (PI), polypropylene / polyethylene / polypropylene triple-layer composite membrane (PP / PE / PP), cellulose nonwoven separator, and separator with ceramic coating.

[0051] In battery manufacturing, the positive electrode, separator, and negative electrode are wound or stacked to obtain a bare cell, which is then packaged into a pre-stamped aluminum-plastic film bag. After the packaged battery is dried at 85°C, the electrolyte is injected into the dried battery. The battery undergoes resting, formation, and secondary sealing to complete battery manufacturing.

[0052] In another aspect, the present invention provides a battery pack comprising the battery as described above.

[0053] Since the battery pack provided by the present invention includes the above-mentioned battery, it has excellent cycle performance and safety.

[0054] In another aspect, the present invention provides an electrical device comprising a battery as described above or a battery pack as described above.

[0055] This invention does not limit the specific types of electrical equipment, and may include any equipment that requires batteries to power it, such as electric vehicles, mobile phones, smart home devices, robots, drones, e-cigarettes, and speakers.

[0056] The electrical equipment provided by the present invention includes the battery described above or the battery pack described above, and therefore has good safety performance and cycle stability.

[0057] The electrolyte provided by the present invention will be described in detail below through specific embodiments.

[0058] Unless otherwise specified, the reagents, materials and instruments used in the following examples are all conventional reagents, materials and instruments in the art, and can be obtained commercially. The reagents involved can also be synthesized by conventional methods in the art.

[0059] Example 1

[0060] The electrolyte preparation method provided in this embodiment includes the following steps:

[0061] A highly dispersed and clear electrolyte was prepared by mixing sodium electrolyte (NaPF6), ester solvent (containing PC, EC, and DEC in a volume ratio of 3:2:6), and flame retardant additive (trimethylsiloxy-terminated polydimethylsiloxane (Mw=770) and PFPN in a mass ratio of 1:2) in a mass ratio of 2:6:1.

[0062] The mass of polydimethylsiloxane is 1.0 mg, and the mass of PFPN is 2.0 mg.

[0063] Example 2

[0064] The electrolyte preparation method provided in this embodiment includes the following steps:

[0065] A highly dispersed and clear electrolyte was prepared by mixing sodium electrolyte (NaPF6), ester solvent (containing PC, EC, and DEC in a volume ratio of 3:2:6), and flame retardant additive (trimethylsiloxy-terminated polydimethylsiloxane (Mw=770) and PFPN in a mass ratio of 1:1) in a mass ratio of 2:6:1.

[0066] The mass of polydimethylsiloxane is 2.0 mg, and the mass of PFPN is 2.0 mg.

[0067] Example 3

[0068] The electrolyte preparation method provided in this embodiment includes the following steps:

[0069] A highly dispersed and clear electrolyte was prepared by mixing sodium electrolyte (NaClO4), ester solvent (containing PC, EC, and DEC in a volume ratio of 3:2:6), and flame retardant additive (trimethylsiloxy-terminated polydimethylsiloxane (Mw=770) and PFPN in a mass ratio of 1:2) in a mass ratio of 2:6:1.

[0070] The mass of polydimethylsiloxane is 1.0 mg, and the mass of PFPN is 2.0 mg.

[0071] Example 4

[0072] The electrolyte preparation method provided in this embodiment includes the following steps:

[0073] A highly dispersed and clear electrolyte was prepared by mixing sodium electrolyte (NaPF6), ester solvent (containing PC and EC in a volume ratio of 3:2), and flame retardant additive (trimethylsiloxy-terminated polydimethylsiloxane (Mw=770) and PFPN in a mass ratio of 1:2) in a mass ratio of 2:6:1.

[0074] The mass of polydimethylsiloxane is 1.0 mg, and the mass of PFPN is 2.0 mg.

[0075] Example 5

[0076] The electrolyte preparation method provided in this embodiment includes the following steps:

[0077] A highly dispersed and clear electrolyte was prepared by mixing sodium electrolyte (NaPF6), ester solvent (containing PC, EC, and DEC in a volume ratio of 3:2:6), and flame retardant additive (trimethylsiloxy-terminated polydimethylsiloxane (Mw=770) and PFPN in a mass ratio of 1:3) in a mass ratio of 2:6:1.

[0078] The mass of polydimethylsiloxane is 1.0 mg, and the mass of PFPN is 3.0 mg.

[0079] Example 6

[0080] The preparation method of the electrolyte provided in this embodiment is basically the same as that in Example 1, except that:

[0081] The electrolyte contains sodium salt (NaPF6), ester solvents (containing PC, EC, and DEC in a volume ratio of 3:2:6), and the flame retardant additives are in a mass ratio of 2:5:3.

[0082] Example 7

[0083] The preparation method of the electrolyte provided in this embodiment is basically the same as that in Example 1, except that:

[0084] Trimethylsiloxy-terminated polydimethylsiloxane (Mw=770) and PFPN in a mass ratio of 2:1.

[0085] Example 8

[0086] The electrolyte preparation method provided in this embodiment includes the following steps:

[0087] A highly dispersed and clear electrolyte was prepared by mixing sodium electrolyte (NaPF6), ester solvent (containing PC, EC, and DEC in a volume ratio of 3:2:6), and flame retardant additives (hydroxyl-terminated polydimethylsiloxane (Mw=500) and PFPN in a mass ratio of 2:1) in a mass ratio of 2:6:1.

[0088] The mass of polydimethylsiloxane is 2.0 mg, and the mass of PFPN is 1.0 mg.

[0089] Example 9

[0090] The preparation method of the electrolyte provided in this embodiment is basically the same as that in Example 1, except that:

[0091] Sodium hexafluorophosphate was replaced with lithium hexafluorophosphate.

[0092] Comparative Example 1

[0093] The preparation method of the electrolyte provided in this comparative example includes the following steps:

[0094] A highly dispersed and clear electrolyte was prepared by mixing sodium salt of electrolyte (NaPF6) and ester solvent (containing PC, EC, and DEC in a volume ratio of 3:2:6) at a mass ratio of 1:9.

[0095] Comparative Example 2

[0096] The preparation method of the electrolyte provided in this comparative example includes the following steps:

[0097] A highly dispersed and clear electrolyte was prepared by mixing sodium electrolyte (NaPF6), ester solvent (containing PC, EC, and DEC in a volume ratio of 3:2:6) and hydroxyl-terminated polydimethylsiloxane (Mw=500) in a mass ratio of 1:6:3.

[0098] Comparative Example 3

[0099] The preparation method of the electrolyte provided in this comparative example includes the following steps:

[0100] A highly dispersed and clear electrolyte was prepared by mixing sodium electrolyte (NaPF6), ester solvent (containing PC, EC, and DEC in a volume ratio of 3:2:6) and ethoxy(pentafluoro)cyclotriphosphazene (PFPN) in a mass ratio of 1:6:3.

[0101] Comparative Example 4

[0102] The preparation method of the electrolyte provided in this comparative example is basically the same as that in comparative example 3, except that:

[0103] Replace NaPF6 with lithium hexafluorophosphate.

[0104] Test case

[0105] The electrolytes provided in Examples 1-8 and Comparative Examples 1-3 were used to prepare pouch cells, respectively, including the following steps:

[0106] The positive electrode active materials from the examples and comparative examples were mixed with conductive carbon black and PVDF at a weight ratio of 96%:2%:2%, respectively, and dispersed to obtain a positive electrode slurry. This slurry was then coated onto an aluminum foil current collector, with a positive electrode areal density of 2.03 g / cm³. 3 The positive electrode sheet is prepared by rolling.

[0107] 2) Hard carbon, styrene-diene rubber (SBR), sodium carboxymethyl cellulose, and conductive carbon black are mixed in a weight ratio of 94%:3%:2%:1%. The mixture is then dispersed in water to obtain a negative electrode slurry. This slurry is coated onto an aluminum current collector, followed by rolling and drying to obtain the negative electrode sheet.

[0108] 3) Assemble the positive electrode, negative electrode, and separator into a sodium-ion battery, and inject a flame-retardant electrolyte. The electrolyte is added in a mass ratio of sodium salt, organic solvent, and the flame-retardant additive of 1-20:60-90:1-20, and then processed through encapsulation and formation capacity testing.

[0109] The electrolytes provided in Example 9 and Comparative Example 4 were used to prepare pouch cells, respectively, including the following steps:

[0110] The positive electrode active materials from the examples and comparative examples were mixed with conductive carbon black and PVDF at a weight ratio of 96%:2%:2%, respectively, and dispersed to obtain a positive electrode slurry. This slurry was then coated onto an aluminum foil current collector, with a positive electrode areal density of 4.12 g / cm³. 3 The positive electrode sheet is prepared by rolling.

[0111] 2) Artificial graphite, styrene-diene rubber (SBR), sodium carboxymethyl cellulose, and conductive carbon black are mixed in a weight ratio of 94%:3%:2%:1%. The mixture is then dispersed in water to obtain a negative electrode slurry. This slurry is coated onto a copper current collector, followed by rolling and drying to obtain the negative electrode sheet.

[0112] 3) Assemble the positive electrode, negative electrode, and separator into a lithium-ion battery, and inject a flame-retardant electrolyte. The electrolyte is prepared by mixing ethylene carbonate (EC): diethyl carbonate (DEC): propylene carbonate (PC) in a volume ratio of 2:5:3. Then, add 5% fluoroethylene carbonate (FEC) and 1% lithium hexafluorophosphate (LiPF6) by volume, along with flame-retardant additives at 2% of the total electrolyte volume. The battery is then encapsulated and subjected to formation and capacity testing.

[0113] 1. Safety performance test

[0114] The assembled pouch cells were adjusted to 100% SOC and tested using an accelerated calorimeter (ARC). The test results are shown in Table 1.

[0115] Table 1

[0116]

[0117]

[0118] As can be seen from the table, the self-heating initiation temperature (151.7℃) and thermal runaway initiation temperature (253.1℃) of the sodium-ion pouch battery in Example 1 are higher than those of Examples 2-8 and Comparative Examples 1-3, while its maximum thermal runaway temperature (448.6℃) is lower than that of Comparative Examples 1-3. This indicates that the sodium-ion battery in Example 1 containing a 1:2 mass ratio of polydimethylsiloxane to PFPN flame retardant additive has better safety performance. The self-heating initiation temperature (103.8℃) and thermal runaway initiation temperature (180.5℃) of the lithium-ion pouch battery in Example 9 are higher than those of Comparative Example 4, indicating that the lithium-ion battery in Example 9 containing a 1:2 mass ratio of polydimethylsiloxane to PFPN flame retardant additive has better safety performance.

[0119] 2. Electrochemical performance testing

[0120] The assembled pouch cells were tested in an electrochemical testing cabinet. The voltage range for Examples 1-8 and Comparative Examples 1-3 was 2V-3.4V, and the voltage range for Example 9 and Comparative Example 4 was 2.5-3.65V. The test results are shown in Table 2.

[0121] Table 2

[0122]

[0123]

[0124] As shown in Table 2, the sodium-ion battery in Example 1 containing a 1:2 molar ratio of polydimethylsiloxane to PFPN flame retardant additive maintained a discharge capacity of 1.45 Ah / g after 500 cycles at a current density of 1.5 A / g, with a capacity retention of 96.6% and an energy efficiency of 95.5%. Example 3, at a current density of 1.5 A / g, maintained a discharge capacity of 1.43 Ah / g after 500 cycles, with a capacity retention of 97.0% and an energy efficiency of 95.2%. The performance of these two examples of sodium-ion batteries is superior to other examples and Comparative Examples 1-3. Example 9 exhibited a discharge capacity of 1.60 Ah / g after 500 cycles, with a capacity retention of 95.1% and an energy efficiency of 94.7%, which is superior to Comparative Example 4. Electrolyte ignition experiments showed that, compared to electrolytes with other ratios, the self-extinguishing time in Examples 1 and 3 was shorter, indicating better flame retardant performance. Therefore, flame-retardant electrolytes containing both polydimethylsiloxane and PFPN additives help improve the capacity retention, cycle stability, and flame retardancy of sodium-ion batteries.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electrolyte, characterized in that, It includes flame retardant additives; the flame retardant additives include polysiloxane additives and phosphazene additives.

2. The electrolyte according to claim 1, characterized in that, The mass ratio of the polysiloxane additive to the phosphazene additive is 1:(1-3).

3. The electrolyte according to claim 1 or 2, characterized in that, The polysiloxane additives include at least one of polydimethylsiloxane, polyphenylsiloxane, and epoxysilane. And / or, the phosphazene additive is at least one of ethoxy(pentafluoro)cyclotriphosphazene, methoxypentafluorocyclotriphosphazene, hexafluorocyclotriphosphazene, and phenoxycyclotriphosphazene.

4. The electrolyte according to claim 3, characterized in that, The end capping of at least one end of the polysiloxane additive is selected from at least one of hydroxyl, amino, epoxy or trimethylsiloxy. And / or, the molecular weight of the polysiloxane additive is less than 1000.

5. The electrolyte according to claim 1, characterized in that, The polysiloxane additive is polydimethylsiloxane, and the phosphazene additive is ethoxy(pentafluoro)cyclotriphosphazene. The mass ratio of the polydimethylsiloxane to the ethoxy(pentafluoro)cyclotriphosphazene is 1:(1-2).

6. The electrolyte according to claim 1, characterized in that, The electrolyte also includes sodium salts and ester solvents; The mass ratio of the sodium salt, the ester solvent, and the flame retardant additive is (1-20):(60-90):(1-20).

7. The electrolyte according to claim 6, characterized in that, The sodium salt includes at least one of sodium hexafluorophosphate, sodium perchlorate, sodium difluorosulfonate imide, and sodium bis(trifluoromethylsulfonyl)imide. And / or, the ester solvent includes at least one of ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, and dimethyl carbonate.

8. A battery, characterized in that, Includes the electrolyte as described in any one of claims 1-7.

9. A battery pack, characterized in that, Includes the battery as described in claim 8.

10. An electrical appliance, characterized in that, Includes the battery as described in claim 8 or the battery pack as described in claim 9.

Images