Carbonic ester containing unsaturated bond and preparation method and application thereof
By using carbonate containing unsaturated bonds as additives in lithium-ion batteries to form a stable solid electrolyte layer, the problem of improving battery performance in the prior art is solved, and the battery life is extended and the feasibility of industrial production is achieved.
Patent Information
- Application Number
- CN202411196803.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2024-12-20
AI Technical Summary
The performance improvement of existing lithium-ion batteries is difficult to meet the growing application needs, especially in electrolyte additives, and there is a lack of materials that can effectively protect the negative electrode interface.
A carbonate containing an unsaturated bond was developed, prepared by reacting with alcohol and carbon dioxide in the presence of a composite catalyst to form a solid electrolyte layer (SEI) capable of forming a stable solid electrolyte layer (SEI) on the negative electrode and used as an additive for lithium-ion batteries.
This carbonate can significantly improve battery life and achieve high yield and high purity industrial production through simplified preparation methods and low-cost processes, which is suitable for negative electrode protection of lithium-ion batteries.
Smart Images
Figure CN119161250A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of lithium ion battery material preparation, and relates to a carbonate containing an unsaturated bond and a preparation method and application thereof. Background Art
[0002] In recent years, lithium-ion batteries have developed rapidly and have been widely used in electric vehicles, energy storage, and various types of power tools. The industrial scale of new energy vehicles, energy storage, and other fields will maintain an exponential growth trend in the next few years, which will greatly stimulate the production demand of lithium-ion batteries. With the increasing use of lithium-ion batteries in different fields, higher requirements are placed on the performance of batteries. The use of electrolyte additives is the most economical and effective means to improve the performance of lithium-ion batteries.
[0003] Developing carbonate additives that can further improve battery performance is a research focus in this field. Summary of the invention
[0004] In view of the deficiencies of the prior art, the object of the present invention is to provide a carbonate containing unsaturated bonds and a preparation method and application thereof. The carbonate containing unsaturated bonds of the present invention contains multiple unsaturated bonds, can form a stable solid electrolyte layer (SEI) at the negative electrode to protect the negative electrode interface, and improve the battery life. In addition, the preparation method thereof is simple, has no by-products, has mild reaction conditions, is not easy to corrode equipment, has low cost, high yield, and high product purity, and is suitable for industrial production.
[0005] To achieve this object, the present invention adopts the following technical solutions:
[0006] In one aspect, the present invention provides a carbonate containing an unsaturated bond, wherein the carbonate containing an unsaturated bond has a structure as shown in the following formula I:
[0007]
[0008] Wherein R1 is selected from substituted or unsubstituted C1-C3 straight chain alkane groups, and the substituents in the substituted C1-C3 alkane groups are selected from halogens; two R1s are the same or different;
[0009] R3 and R4 are independently selected from substituted or unsubstituted C1-C3 straight-chain alkylene groups, wherein the substituents in the substituted C1-C3 straight-chain alkylene groups are selected from halogens;
[0010] R2 is selected from substituted or unsubstituted C1-C5 straight or branched alkane groups, and the substituents in the substituted C1-C5 alkane groups are selected from halogens.
[0011] The carbonate containing unsaturated bonds in the present invention contains two double bonds, and when applied as an additive for lithium-ion batteries, it can form a stable solid electrolyte layer (SEI) at the negative electrode to protect the negative electrode interface and improve the battery life.
[0012] Preferably, R1 is independently selected from the following groups or the following groups substituted with halogen: CH3-, CH3-CH2- or CH3-CH2-CH2-.
[0013] Preferably, R3 and R4 are independently selected from any one of -CH2-, -CH2-CH2-, or -CH2-CH2-CH2-.
[0014] Preferably, R2 is independently selected from the following groups or the following groups substituted with halogen: CH3-, CH3-CH2-, CH3-CH2-CH2-, CH3-CH2-CH2-CH2-, CH3-CH2-CH2-CH2-CH2-, -CH2(CH3)2, -CH2 CH2(CH3)2, -CH2(CH3)(CH2CH3), -CH2(CH2CH3)2 or -CH2(CH3)(CH2CH2CH3).
[0015] Preferably, the carbonate containing an unsaturated bond is any one of the following compounds:
[0016]
[0017] On the other hand, the present invention provides a method for preparing the carbonate containing unsaturated bonds as described above, the preparation method comprising the following steps:
[0018] (1) reacting the compound represented by formula II with alcohol R1-OH and carbon dioxide in the presence of a composite catalyst to obtain butyne dicarbonate, wherein the composite catalyst is a combination of a metal and a metal oxide;
[0019] (2) adding an olefin compound represented by formula III to the reaction solution of step (1) to react to obtain a carbonate containing an unsaturated bond represented by formula I;
[0020]
[0021] In the present invention, the use of a composite catalyst can effectively improve the reaction activity and yield, inhibit side reactions and improve product purity. The two-step reaction is simple to operate, has no by-products and is environmentally friendly. The reaction environment is neutral and does not require high corrosion resistance of the equipment. The same composite catalyst is used in the two steps, no additional solvent is required, methanol can be recovered and reused, the purification method is simple, and cost is saved.
[0022] Preferably, the mass ratio of the metal to the metal oxide in the composite catalyst is 1:(1-4), such as 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5 or 1:4, preferably 1:3.
[0023] Preferably, the metal in the composite catalyst is selected from any one of Fe, Ni, Cu, Zn, Mn or Sn, or a combination of at least two thereof.
[0024] Preferably, the metal oxide in the composite catalyst is selected from any one of Fe3O4, MnO2, CuO, Al2O3, MgO or V2O5, or a combination of at least two thereof.
[0025] Preferably, the amount of the composite catalyst used in step (1) is 0.2-5% by mass of the compound represented by formula II, for example 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 5%, preferably 3.5%.
[0026] Preferably, the molar ratio of the compound represented by formula II in step (1) to the alcohol R1-OH is 1:(2-2.5), for example 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4 or 1:2.5, preferably 1:2.2.
[0027] In step (1), the carbon dioxide is added into the reaction system by gas introduction.
[0028] Preferably, the reaction in step (1) is carried out at a pressure of 0.5-5 MPa; for example, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 4 MPa or 5 MPa.
[0029] Preferably, the reaction temperature in step (1) is 80-120°C, for example 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or 120°C.
[0030] Preferably, the reaction time of step (1) is 2-4 h, for example 2 h, 2.5 h, 3 h, 3.5 h or 4 h.
[0031] Preferably, the molar ratio of the olefin compound represented by formula III in step (2) to the compound represented by formula II in step (1) is (1-1.2):1, for example, 1:1, 1.01:1, 1.05:1, 1.1:1 or 1.2:1, preferably 1.05:1.
[0032] Preferably, the reaction temperature in step (2) is 70-90°C, such as 70°C, 75°C, 80°C, 85°C, or 90°C.
[0033] Preferably, the reaction time of step (2) is 2-4 h, for example, 1 h, 1.5 h, 2 h, 2.5 h or 3 h.
[0034] Preferably, the reaction in step (2) is carried out at a pressure of 0.5-5 MPa, for example 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 4 MPa or 5 MPa.
[0035] After the reaction in step (2) is completed, the reaction solution is filtered, and the filtrate is distilled and purified to obtain the purified carbonate containing unsaturated bonds.
[0036] As a preferred technical solution of the present invention, the preparation method specifically comprises the following steps:
[0037] (1) Add the compound represented by formula II, alcohol R1-OH and composite catalyst into a reaction kettle, introduce carbon dioxide gas, and react at 80-120°C for 2-4 hours under a pressure of 0.5-5MPa; the molar ratio of the compound represented by formula II to the alcohol R1-OH is 1:(2-2.5); the composite catalyst is a combination of metal and metal oxide; the metal is selected from any one or a combination of at least two of Fe, Ni, Cu, Zn, Mn or Sn, and the metal oxide is selected from any one or a combination of at least two of Fe3O4, MnO2, CuO, Al2O3, MgO or V2O5; the mass ratio of metal to metal oxide in the composite catalyst is 1:(1-4), and the amount of the composite catalyst used in step (1) is 0.2-5% of the mass of 1,4-butynediol;
[0038] (2) After the reaction of step (1) is completed, the olefin compound represented by formula III is added to the reactor in a molar ratio of (1-1.2):1 to the compound represented by formula II, and the reaction is carried out at 70-90° C. for 2-4 hours under a pressure of 0.5-5 MPa. After the reaction is completed, the filtrate is filtered and the filtrate is purified by distillation to obtain a carbonate containing an unsaturated bond represented by formula I.
[0039] In another aspect, the present invention provides the use of the carbonate containing unsaturated bonds as described above as an additive for lithium ion battery electrolyte.
[0040] Compared with the prior art, the present invention has the following beneficial effects:
[0041] (1) The unsaturated bond-containing carbonate of the present invention contains multiple unsaturated bonds, which can form a stable solid electrolyte layer (SEI) at the negative electrode to protect the negative electrode interface and improve the battery life.
[0042] (2) In the preparation method of the carbonate containing unsaturated bonds of the present invention, the composite catalyst can effectively improve the reaction activity and yield; inhibit side reactions and improve product purity; the two-step reaction is simple to operate; there are no by-products and it is environmentally friendly; the reaction environment is neutral and does not require high corrosion resistance of the equipment; the same composite catalyst is used in the two steps, there is no additional solvent, methanol can be recycled and reused, the purification method is simple, and cost is saved. The preparation method of the present invention can effectively reduce production costs, improve product yield and purity, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Figure 1 This is the H NMR spectrum of the product prepared in Example 1. DETAILED DESCRIPTION
[0044] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.
[0045] Example 1
[0046] In this embodiment, a carbonate A containing an unsaturated bond is provided. The preparation method comprises the following steps:
[0047] Add 100g 1,4-butynediol, 82g methanol, 3.5g composite catalyst (including metal Ni and metal oxide CuO) to the reactor, the mass ratio of metal: metal oxide in the composite catalyst is 1:3. Fill with carbon dioxide gas to 1.6MPa, heat to 110℃ and react at constant temperature and pressure for 3 hours. Release the pressure after the reaction. Add 120g 1-heptene to the reactor, flush with air and pressurize to 0.9MPa, heat to 85℃, and react at constant temperature and pressure for 3 hours. After the reaction, cool to room temperature and filter, and purify the filtrate by distillation. Obtain carbonate A326.2g, yield 93.6%, purity 99.97%.
[0048] The product has a hydrogen nuclear magnetic resonance spectrum (instrument model Bruker AVANCE NEO 600MHz), a hydrogen spectrum (the deuterated reagent used is deuterated dimethyl sulfoxide) as shown in Figure 1 As shown, 1H NMR: δppm 0.87(3H,t,J=7.0Hz),1.23-1.48(4H,1.29(h,J=7.0Hz),1.41(tt,J=7.4, 7.0Hz)),1.97(2H,q,J=7.4Hz),2.66(2H,d,J=7.4Hz),3.77-3.87(6H,3.82 (s),3.82(s)),4.59-4.74(4H,4.65(d,J=6.6Hz),4.69(s)),5.35-5.56(3 H, 5.42 (dt, J = 15.7, 7.4Hz), 5.48 (dt, J = 15.7, 7.4Hz), 5.46 (t, J = 6.6Hz)).
[0049] Example 2
[0050] The difference from Example 1 is that 74.5 g of methanol is added to obtain 317.8 g of carbonate A with a yield of 91.2% and a purity of 99.95%.
[0051] Example 3
[0052] The difference from Example 1 is that 93 g of methanol is added to obtain 322.0 g of carbonate A with a yield of 91.2% and a purity of 99.95%.
[0053] Example 4
[0054] The difference from Example 1 is that 115 g of 1-heptene is added to obtain 319.6 g of carbonate A with a yield of 91.7% and a purity of 99.95%.
[0055] Example 5
[0056] The difference from Example 1 is that 136 g of 1-heptene is added to obtain 324.5 g of carbonate A with a yield of 93.1% and a purity of 99.97%.
[0057] Example 6
[0058] The difference from Example 1 is that 0.2 g of composite catalyst is added to obtain 307.7 g of carbonate A with a yield of 88.3% and a purity of 99.92%.
[0059] Example 7
[0060] The difference from Example 1 is that 5 g of composite catalyst is added to obtain 15.4 g of carbonate A3 with a yield of 90.5% and a purity of 99.94%.
[0061] Example 8
[0062] The difference from Example 1 is that the first step reaction temperature is 80°C and the pressure is 5 MPa, and the second step reaction temperature is 70°C and the pressure is 5 MPa. 303.9 g of carbonate A is obtained with a yield of 87.2% and a purity of 99.91%.
[0063] Example 9
[0064] The difference from Example 1 is that the first step reaction temperature is 120°C and the pressure is 0.5 MPa, and the second step reaction temperature is 90°C and the pressure is 0.5 MPa. 309.8 g of carbonate A is obtained with a yield of 88.9% and a purity of 99.92%.
[0065] Example 10
[0066] In this embodiment, a carbonate B containing an unsaturated bond is provided. The preparation method comprises the following steps:
[0067] Add 100g 1,4-butynediol, 82g methanol, 3.5g composite catalyst (including metal Ni and metal oxide MnO2) to the reactor, the mass ratio of metal: metal oxide in the composite catalyst is 1:3. Fill with carbon dioxide gas to 1.6MPa, heat to 80℃ and react at constant temperature and pressure for 4 hours. Release the pressure after the reaction. Add 70g 1-butene to the reactor, flush with air and pressurize to 2MPa, heat to 90℃, and react at constant temperature and pressure for 2 hours. After the reaction, cool to room temperature and filter, and purify the filtrate by distillation. Obtain carbonate B278.2g, yield 92.8%, purity 99.95%.
[0068] The data of the product's hydrogen nuclear magnetic resonance spectrum (instrument model Bruker AVANCE NEO 600MHz, the deuterated reagent used is deuterated dimethyl sulfoxide) are as follows: 1 H NMR: δppm 1.53(3H,d,J=7.2Hz),2.65(2H,d,J=7.4Hz),3.77-3.87(6H,3.82(s),3.82(s)),4.59-4.74(4H,4.65(d,J= 6.6Hz), 4.69 (s)), 5.32-5.52 (3H, 5.39 (dq, J = 15.7, 7.2Hz), 5.41 (dt, J = 15.7, 7.4Hz), 5.46 (t, J = 6.6Hz)).
[0069] Embodiment 11
[0070] In this embodiment, a carbonate C containing an unsaturated bond is provided. The preparation method comprises the following steps:
[0071] Add 100g 1,4-butynediol, 118g ethanol, 3.5g composite catalyst (including metal Fe and metal oxide Fe3O4) to the reactor, the mass ratio of metal: metal oxide in the composite catalyst is 1:1. Fill with carbon dioxide gas to 3MPa, heat to 100℃ and react at constant temperature and pressure for 2 hours. Release the pressure after the reaction. Add 86g 1-pentene to the reactor, flush with air and pressurize to 4MPa, heat to 90℃, and react at constant temperature and pressure for 2 hours. After the reaction is completed, cool to room temperature and filter, and purify the filtrate by distillation. Obtain carbonate C312g, yield 89.5%, purity 99.81%.
[0072] The data of the product's hydrogen nuclear magnetic resonance spectrum (instrument model Bruker AVANCE NEO 600MHz, the deuterated reagent used is deuterated dimethyl sulfoxide) are as follows: 1 H NMR: δppm 1.09(3H,t,J=7.5Hz),1.18-1.32(6H,1.24(t,J=7.1Hz),1.26(t,J=7.1Hz)),2 .07(2H,qd,J=7.5,6.9Hz),2.66(2H,d,J=7.4Hz),4.22-4.33(4H,4.27(q,J=7.1 Hz),4.28(q,J=7.1Hz)),4.59-4.74(4H,4.65(d,J=6.6Hz),4.69(s)),5.31-5. 55(3H, 5.39(dt,J=15.7,6.9Hz), 5.47(dt,J=15.7,7.4Hz), 5.46(t,J=6.6Hz)).
[0073] Example 12
[0074] In this embodiment, a carbonate D containing an unsaturated bond is provided. The preparation method comprises the following steps:
[0075] Add 133g 1,4-hexynediol, 82g methanol, 4.7g composite catalyst (including metal Sn and metal oxide MgO) to the reactor, the mass ratio of metal: metal oxide in the composite catalyst is 1:3. Fill with carbon dioxide gas to 1.6MPa, heat to 110℃ and react at constant temperature and pressure for 3 hours. Release the pressure after the reaction. Add 86g 1-pentene to the reactor, flush with air and pressurize to 0.9MPa, heat to 85℃, and react at constant temperature and pressure for 3 hours. After the reaction is completed, cool to room temperature and filter, and purify the filtrate by distillation. Obtain carbonate D326.2g, yield 93.6%, purity 99.97%.
[0076] The data of the product's hydrogen nuclear magnetic resonance spectrum (instrument model Bruker AVANCE NEO 600MHz, the deuterated reagent used is deuterated dimethyl sulfoxide) are as follows: 1 H NMR: δppm 1.09(3H,t,J=7.5Hz),2.07(2H,qd,J=7.5,6.9Hz),2.49-2.70(6H,2.55(t,J= 7.4Hz),2.57(td,J=7.4,7.2Hz),2.64(d,J=7.4Hz)),3.77-3.87(6H,3.82(s) ,3.82(s)),4.38-4.52(4H,4.44(t,J=7.4Hz),4.46(t,J=7.4Hz)),5.31-5.47 (3H, 5.37 (t, J = 7.2Hz), 5.39 (dt, J = 15.7, 6.9Hz), 5.40 (dt, J = 15.7, 7.4Hz)).
[0077] Example 13
[0078] In this embodiment, a carbonate E containing an unsaturated bond is provided. The preparation method comprises the following steps:
[0079] Add 100g 1,4-butynediol, 128g fluoromethanol, 3.5g composite catalyst (including metal Ni and metal oxide V2O5) to the reactor, the mass ratio of metal: metal oxide in the composite catalyst is 1:3. Fill with carbon dioxide gas to 1.6MPa, heat to 110℃ and react at constant temperature and pressure for 3 hours. Release the pressure after the reaction. Add 86g 1-pentene to the reactor, flush with air and pressurize to 0.9MPa, heat to 85℃, and react at constant temperature and pressure for 3 hours. After the reaction is completed, cool to room temperature and filter, and purify the filtrate by distillation. Obtain carbonate E323.6g, yield 90.4%, purity 99.83%.
[0080] The data of the product's hydrogen nuclear magnetic resonance spectrum (instrument model Bruker AVANCE NEO 600MHz, the deuterated reagent used is deuterated dimethyl sulfoxide) are as follows: 1H NMR: δppm 1.09(3H,t,J=7.5Hz),2.07(2H,qd,J=7.5,6.9Hz),2.66(2H,d,J=7.4Hz),4 .28-4.41(4H,4.34(t,J=6.6Hz),4.35(t,J=6.6Hz)),4.49-4.74(8H,4.55( t,J=6.6Hz),4.55(t,J=6.6Hz),4.65(d,J=6.6Hz),4.69(s)),5.31-5.55(3 H, 5.39 (dt, J = 15.7, 6.9 Hz), 5.47 ( dt, J = 15.7, 7.4 Hz), 5.46 ( t, J = 6.6 Hz)).
[0081] Embodiment 14
[0082] In this embodiment, a carbonate F containing an unsaturated bond is provided. The preparation method comprises the following steps:
[0083] Add 100g 1,4-butynediol, 82g methanol, 3.5g composite catalyst (including metal Zn and metal oxide V2O5) to the reactor, the mass ratio of metal: metal oxide in the composite catalyst is 1:3. Fill with carbon dioxide gas to 1.6MPa, heat to 110℃ and react at constant temperature and pressure for 3 hours. Release the pressure after the reaction. Add 86g 5,5,5-trifluoro-1-pentene to the reactor, flush with air and pressurize to 0.9MPa, heat to 85℃, and react at constant temperature and pressure for 3 hours. After the reaction is completed, cool to room temperature and filter, and purify the filtrate by distillation. Obtain carbonate F343.6g, yield 90.7%, purity 99.85%.
[0084] The data of the product's hydrogen nuclear magnetic resonance spectrum (instrument model Bruker AVANCE NEO 600MHz, the deuterated reagent used is deuterated dimethyl sulfoxide) are as follows: 1 H NMR: δppm 2.31(2H,d,J=6.5Hz),2.70(2H,d,J=7.4Hz),3.77-3.87(6H,3.82(s),3.82(s)),4.59-4.74(4H,4.65(d,J= 6.6Hz), 4.69 (s)), 5.40-5.66 (3H, 5.46 (t, J = 6.6Hz), 5.49 (dt, J = 15.7, 6.5Hz), 5.58 (dt, J = 15.7, 7.4Hz)).
[0085] Comparative Example 1
[0086] The only difference from Example 1 is that the mass ratio of metal to metal oxide in the composite catalyst is 3:1, and 83.7 g of carbonate A is obtained with a yield of 81.4% and a purity of 98.5%.
[0087] Comparative Example 2
[0088] The only difference from Example 1 is that the composite catalyst does not contain metal, and 234.5 g of carbonate A is obtained with a yield of 67.3% and a purity of 96.7%.
[0089] Comparative Example 3
[0090] The only difference from Example 1 is that the composite catalyst does not contain metal oxides. 39.4 g of carbonate A was obtained with a yield of 68.7% and a purity of 96.9%.
[0091] It can be seen that the preparation method of the present invention can make the product yield as high as 88% or more and the purity as high as 99.9% or more.
[0092] The applicant declares that the present invention illustrates the carbonate containing unsaturated bonds and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.
Claims
1. A carbonate containing an unsaturated bond, characterized in that: The carbonate containing an unsaturated bond has a structure shown in the following formula I: wherein R1 is selected from substituted or unsubstituted C1-C3 straight chain alkane groups, and the substituents in the substituted C1-C3 alkane groups are selected from halogens; R3 and R4 are independently selected from substituted or unsubstituted C1-C3 straight-chain alkylene groups, wherein the substituents in the substituted C1-C3 straight-chain alkylene groups are selected from halogens; R2 is selected from substituted or unsubstituted C1-C5 straight or branched alkane groups, and the substituents in the substituted C1-C5 alkane groups are selected from halogens.
2. The carbonate containing unsaturated bonds according to claim 1, characterized in that Said R1 is independently selected from the following groups or the following groups substituted by halogen: CH3-, CH3-CH2- or CH3-CH2-CH2-; Preferably, R3 and R4 are independently selected from any one of -CH2-, -CH2-CH2-, or -CH2-CH2-CH2-; Preferably, R2 is independently selected from the following groups or the following groups substituted with halogen: CH3-, CH3-CH2-, CH3-CH2-CH2-, CH3-CH2-CH2-CH2-, CH3-CH2-CH2-CH2-CH2-, -CH2(CH3)2, -CH2 CH2(CH3)2, -CH2(CH3)(CH2CH3), -CH2(CH2CH3)2 or -CH2(CH3)(CH2CH2CH3).
3. The carbonate containing unsaturated bonds according to claim 1 or 2, characterized in that: The carbonate containing an unsaturated bond is any one of the following compounds:
4. The method for preparing a carbonate containing an unsaturated bond according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) reacting the compound represented by formula II with alcohol R1-OH and carbon dioxide in the presence of a composite catalyst to obtain butyne dicarbonate, wherein the composite catalyst is a combination of a metal and a metal oxide; (2) adding an olefin compound represented by formula III to the reaction solution of step (1) to react to obtain a carbonate containing an unsaturated bond represented by formula I; 5. The preparation method according to claim 3, characterized in that: The mass ratio of metal to metal oxide in the composite catalyst is 1:(1-4), preferably 1:3; Preferably, the metal in the composite catalyst is selected from any one or a combination of at least two of Fe, Ni, Cu, Zn, Mn or Sn; Preferably, the metal oxide in the composite catalyst is selected from any one of Fe3O4, MnO2, CuO, Al2O3, MgO or V2O5, or a combination of at least two thereof.
6. The preparation method according to any one of claims 2 to 4, characterized in that: The amount of the composite catalyst used in step (1) is 0.2-5% by mass of the compound represented by formula II, preferably 3.5%; Preferably, the molar ratio of the compound represented by formula II in step (1) to the alcohol R1-OH is 1:(2-2.5), preferably 1:2.
2.
7. The preparation method according to any one of claims 2 to 6, characterized in that: The reaction in step (1) is carried out under a pressure of 0.5-5 MPa; Preferably, the reaction temperature in step (1) is 80-120°C; Preferably, the reaction time in step (1) is 2-4 hours.
8. The preparation method according to any one of claims 2 to 7, characterized in that: The molar ratio of the olefin compound represented by formula III in step (2) to the compound represented by formula II in step (1) is (1-1.2):1; Preferably, the reaction temperature in step (2) is 70-90°C; Preferably, the reaction time in step (2) is 2-4 hours; Preferably, the reaction in step (2) is carried out at a pressure of 0.5-5 MPa; Preferably, after the reaction in step (2) is completed, the reaction solution is filtered, and the filtrate is distilled and purified to obtain the purified carbonate containing an unsaturated bond.
9. The preparation method according to any one of claims 2 to 8, characterized in that: The preparation method specifically comprises the following steps: (1) Add the compound represented by formula II, alcohol R1-OH and composite catalyst into a reaction kettle, introduce carbon dioxide gas, and react at 80-120°C for 2-4 hours under a pressure of 0.5-5MPa; the molar ratio of the compound represented by formula II to the alcohol R1-OH is 1:(2-2.5); the composite catalyst is a combination of metal and metal oxide; the metal is selected from any one or a combination of at least two of Fe, Ni, Cu, Zn, Mn or Sn, and the metal oxide is selected from any one or a combination of at least two of Fe3O4, MnO2, CuO, Al2O3, MgO or V2O5; the mass ratio of metal to metal oxide in the composite catalyst is 1:(1-4), and the amount of the composite catalyst used in step (1) is 0.2-5% of the mass of 1,4-butynediol; (2) After the reaction of step (1) is completed, the olefin compound represented by formula III is added to the reactor in a molar ratio of (1-1.2):1 to the compound represented by formula II, and the reaction is carried out at 70-90° C. for 2-4 hours under a pressure of 0.5-5 MPa. After the reaction is completed, the filtrate is filtered and the filtrate is purified by distillation to obtain a carbonate containing an unsaturated bond represented by formula I.
10. Use of the carbonate containing unsaturated bonds according to claim 1 as an additive for lithium ion battery electrolyte.