Nitrile functional group-containing material as well as preparation method and application thereof
By using pyrosulfuric acid/pyroboronic acid materials containing nitrile functional groups as electrolyte additives, the problem of instability of sulfuric acid esters/boronic acid esters-nitrile materials in high-voltage battery systems has been solved, achieving long-term cycle performance and high yield of high-voltage lithium-ion batteries, which are suitable for large-scale production.
Patent Information
- Application Number
- CN202510932426.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-10-21
AI Technical Summary
Existing sulfate/boronate-nitrile materials have unstable performance in high-voltage battery systems, and their preparation process is complex and has low yield, which cannot meet the long-term application requirements of high-voltage lithium-ion batteries.
Using pyrosulfuric acid/pyroboronic acid materials containing nitrile functional groups as electrolyte additives, free Co³⁺ is captured through chelation to form a stable SEI film, improving the cycle performance of lithium-ion batteries. It also provides a simple preparation method, avoids the use of high-cost catalysts, and is suitable for large-scale industrial production.
It significantly improves the cycle performance of lithium-ion batteries, especially in high-voltage systems, extending battery life. At the same time, the preparation method is simple, energy-efficient, and has a high product yield.
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Figure CN120817876A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of electrolyte materials, and particularly relates to a nitrile functional group-containing material and a preparation method and application thereof. Background Art
[0002] In the field of battery electrolytes, nitrile additives (such as hexanetricarbonitrile and glutaronitrile) have high oxidation potentials (typically above 4.5V vs. Li⁺ / Li), significantly improving electrolyte stability at high voltages and inhibiting solvent decomposition. Furthermore, nitrile additives can form a stable cathode interface film (CEI) on the positive electrode surface, preventing the dissolution of transition metal ions (such as Co²⁺ and Ni²⁺) and reducing electrolyte corrosion on the positive electrode. Sulfate and borate electrolyte additives (such as vinyl sulfate (DTD), propylene sulfate (DPS), dimethyl sulfate (DMS), and lithium difluorooxalatoborate (LiODFB)) offer unique performance advantages in lithium-ion batteries, significantly improving cycle stability, safety, and interfacial properties. Phosphate compounds, as electrolyte additives, can enhance the battery's flame retardancy, film-forming ability, and electrochemical stability.
[0003] Based on the above, since sulfate / borate-nitrile substances can combine the advantages of two functional groups, they have certain application prospects in high-temperature lithium-ion batteries. However, although some technologies have proposed sulfate / borate-nitrile substances, their application performance in high-voltage system batteries is unstable and short-lived. In addition, existing sulfate / borate-nitrile substances also have problems such as complex preparation process, low yield or unstable application effect.
[0004] To this end, the applicant hopes to seek technical solutions to improve the above technical problems. Summary of the Invention
[0005] In view of this, the object of the present invention is to provide a nitrile functional group-containing material and its preparation method and application, which effectively improves the cycle performance of lithium-ion batteries (especially significantly improves the cycle performance in high-voltage systems) and extends battery life; at the same time, the preparation method of the nitrile functional group-containing pyrosulfuric acid / pyroboric acid material provided in this application is simple, the reaction conditions are mild, there are no high reaction requirements, no need to use expensive catalysts, low energy consumption and high product yield, and it is very suitable for large-scale industrial production.
[0006] The technical solution adopted in the present invention is as follows: A nitrile functional group-containing material having the following structural formula: ; where X is or ; Y is or ; R is a C2-C6 carbon chain cyano group or a benzonitrile group.
[0007] Preferably, the nitrile functional group-containing material comprises the following structure: 、 、 and Any one or a mixture of several.
[0008] A nitrile functional group-containing material having the following structural formula: ; Wherein, R is a C2-C6 carbon chain cyano group or a benzonitrile group.
[0009] Preferably, the nitrile functional group-containing material comprises the following structure: and / or .
[0010] Preferably, a method for preparing the above-mentioned material containing nitrile functional groups comprises the following steps: S11, mixing the pyrosulfate, the solvent, and the catalyst to obtain a mixed solution; S12, adding the bromonitrile organic compound and / or the iodonitrile organic compound dropwise to the mixed solution of step S11 under low temperature conditions; S13, after the dropwise addition is completed, the bromonitrile organic compound and / or the iodonitrile organic compound reacts with the pyrosulfate in the mixed solution under certain temperature conditions to obtain a reaction product; S14, after-treating the reaction product to obtain the nitrile functional group-containing material.
[0011] Preferably, a method for preparing the above-mentioned material containing nitrile functional groups comprises the following steps: S21, mixing the pyroborate, the solvent, and the catalyst to obtain a mixed solution; S22, adding the bromonitrile organic compound and / or the iodonitrile organic compound dropwise to the mixed solution of step S21 under low temperature conditions; S23, after the dropwise addition is completed, the bromonitrile organic compound and / or the iodonitrile organic compound reacts with the pyroborate in the mixed solution under certain temperature conditions to obtain a reaction product; S24, after-treating the reaction product to obtain the nitrile functional group-containing material.
[0012] Preferably, the pyrosulfate is sodium pyrosulfate and / or potassium pyrosulfate; the pyroborate is sodium pyroborate and / or potassium pyroborate; the bromononitrile organic compound is any one of 3-bromopropionitrile, 4-bromobutyronitrile, 5-bromovaleronitrile, 4-bromobenzonitrile and 4-bromophenylacetonitrile, or a mixture thereof; and / or the iodonium nitrile organic compound is 3-iodopropionitrile and / or 4-iodobutyronitrile; and / or the solvent is any one of dichloromethane, dichloroethane, ether, acetone, toluene, xylene, ethylbenzene, acetonitrile and water, or a mixture thereof; and / or the catalyst is any one of cuprous oxide, lead acetate, mercuric acetate and mercuric isooctanoate, or a mixture thereof.
[0013] Preferably, the amount of the bromononitrile organic compound and / or the iodononitrile organic compound added is 2.5-4.0 times, preferably 2.5-3.0 times, the molar amount of the corresponding pyrosulfate or pyroborate; and / or the amount of the catalyst added is 0.01-0.2 times, preferably 0.02-0.06 times, the molar amount of the corresponding pyrosulfate or pyroborate; and / or the amount of the solvent added is 2.0-5.0 times, preferably 2.0-3.0 times, the molar amount of the corresponding bromononitrile organic compound and / or the iodononitrile organic compound; and / or the low temperature conditions used for the dropwise addition are set to -10°C to 20°C, preferably -10°C to 0°C; and / or the temperature conditions of the reaction are set to 30-80°C, preferably 40-60°C, and the reaction time is 3-10 hours, preferably 4-6 hours.
[0014] Preferably, according to an application of the above-mentioned nitrile functional group-containing material, the nitrile functional group-containing material is added to the electrolyte of a lithium-ion battery, and the addition amount of the nitrile functional group-containing material in the electrolyte is 0.05-5wt%.
[0015] Preferably, the lithium-ion battery is a lithium cobalt oxide (LiCoO2) ion battery.
[0016] This application specifically proposes a specific pyrosulfuric acid / pyroboric acid material containing a nitrile functional group. When used as an electrolyte additive for lithium-ion batteries, it not only captures free Co³⁺ through chelation, reducing damage to the negative electrode SEI film, but also forms an SEI of lithium (boron) sulfate, effectively improving the cycle performance of the lithium-ion battery (especially significantly improving the cycle performance in a high voltage system of 4.4V-4.8V), and extending the battery life. At the same time, the preparation method of the pyrosulfuric acid / pyroboric acid material containing a nitrile functional group provided in this application is simple, the reaction conditions are mild, there are no high reaction requirements, no need to use expensive catalysts, low energy consumption and high product yield, and it is very suitable for large-scale industrial production. DETAILED DESCRIPTION
[0017] This embodiment proposes a nitrile functional group-containing material having the following structural formula: ; where X is or ; Y is or ; R is a C2-C6 carbon chain cyano group or a benzonitrile group; Preferably, in this embodiment, the nitrile functional group-containing material includes the following structure: 、 、 and Any one or a mixture of several.
[0018] Preferably, this embodiment provides a method for preparing the above-mentioned nitrile functional group-containing material, comprising the following steps: S11, mixing the pyrosulfate, the solvent, and the catalyst to obtain a mixed solution; S12, adding the bromonitrile organic compound and / or the iodonitrile organic compound dropwise to the mixed solution of step S11 under low temperature conditions; preferably, in this step, the low temperature conditions used for the dropwise addition are set to -10°C to 20°C, preferably -10°C to 0°C; S13, after the dropwise addition is completed, the bromonitrile organic compound and / or the iodonitrile organic compound and the pyrosulfate in the mixed solution react under certain temperature conditions to obtain a reaction product; preferably, in this step, the reaction temperature is set to 30-80° C., preferably 40-60° C., and the reaction time is 3-10 hours, preferably 4-6 hours; S14, after post-processing the reaction product to obtain a nitrile functional group-containing material; wherein, preferably, in this embodiment, the post-processing includes filtration and / or rotary evaporation; Preferably, in this embodiment, the pyrosulfate is sodium pyrosulfate and / or potassium pyrosulfate; preferably, in this embodiment, the bromonitrile organic compound is any one of 3-bromopropionitrile, 4-bromobutyronitrile, 5-bromovaleronitrile, 4-bromobenzonitrile and 4-bromophenylacetonitrile, or a mixture thereof; preferably, in this embodiment, the iodinated nitrile organic compound is 3-iodopropionitrile and / or 4-iodobutyronitrile; preferably, in this embodiment, the solvent is any one of dichloromethane, dichloroethane, ether, acetone, toluene, xylene, ethylbenzene, acetonitrile and water, or a mixture thereof; preferably, in this embodiment, the catalyst is any one of cuprous oxide, lead acetate, mercuric acetate and mercuric isooctanoate, or a mixture thereof; Preferably, in this embodiment, the amount of the bromononitrile organic compound and / or the iodononitrile organic compound added is 2.5-4.0 times the molar amount of the corresponding pyrosulfate, more preferably 2.5-3.0 times; preferably, in this embodiment, the amount of the catalyst added is 0.01-0.2 times the molar amount of the corresponding pyrosulfate, more preferably 0.02-0.06 times; preferably, in this embodiment, the amount of the solvent added is 2.0-5.0 times the molar amount of the corresponding bromononitrile organic compound and / or the iodononitrile organic compound, more preferably 2.0-3.0 times.
[0019] This embodiment also proposes another nitrile functional group-containing material having the following structural formula: ; wherein R is a C2-C6 carbon chain cyano group or a benzonitrile group; preferably, in this embodiment, the nitrile functional group-containing material includes the following structure: and / or .
[0020] Preferably, a method for preparing the above-mentioned material containing nitrile functional groups comprises the following steps: S21, mixing the pyroborate, the solvent, and the catalyst to obtain a mixed solution; S22, adding the bromonitrile organic compound and / or the iodonitrile organic compound dropwise to the mixed solution of step S21 under low temperature conditions; preferably, in this step, the low temperature conditions used for the dropwise addition are set to -10°C to 20°C, preferably -10°C to 0°C; S23, after the dropwise addition is completed, the bromonitrile organic compound and / or the iodonitrile organic compound and the pyroborate in the mixed solution react under certain temperature conditions to obtain a reaction product; preferably, in this step, the reaction temperature is set to 30-80 ° C, preferably 40-60 ° C, and the reaction time is 3-10 hours, preferably 4-6 hours; S24, after-treating the reaction product to obtain a material containing a nitrile functional group; wherein, preferably, in this embodiment, the after-treatment includes filtering and / or rotary evaporation; Preferably, in this embodiment, the pyroborate is sodium pyroborate and / or potassium pyroborate; preferably, in this embodiment, the bromonitrile organic compound is any one of 3-bromopropionitrile, 4-bromobutyronitrile, 5-bromovaleronitrile, 4-bromobenzonitrile and 4-bromophenylacetonitrile, or a mixture thereof; preferably, in this embodiment, the iodonitrile organic compound is 3-iodopropionitrile and / or 4-iodobutyronitrile; preferably, in this embodiment, the solvent is any one of dichloromethane, dichloroethane, ether, acetone, toluene, xylene, ethylbenzene, acetonitrile and water, or a mixture thereof; preferably, in this embodiment, the catalyst is any one of cuprous oxide, lead acetate, mercuric acetate and mercuric isooctanoate, or a mixture thereof; Preferably, in this embodiment, the amount of the bromononitrile organic compound and / or the iodononitrile organic compound added is 2.5-4.0 times the molar amount of the corresponding pyroborate, more preferably 2.5-3.0 times; preferably, in this embodiment, the amount of the catalyst added is 0.01-0.2 times the molar amount of the corresponding pyroborate, more preferably 0.02-0.06 times; preferably, in this embodiment, the amount of the solvent added is 2.0-5.0 times the molar amount of the corresponding bromononitrile organic compound and / or the iodononitrile organic compound, more preferably 2.0-3.0 times.
[0021] Preferably, this embodiment also proposes an application of the nitrile functional group material described above, adding the nitrile functional group material to the electrolyte of a lithium ion battery, and the amount of the nitrile functional group material added to the electrolyte is 0.05-5wt%, more preferably 0.08%-3%; further preferably, in this embodiment, the lithium ion battery is a lithium cobalt oxide LiCoO2 ion battery.
[0022] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.
[0023] Based on the above-described embodiments, the present application further proposes the following specific embodiments: First, it should be noted that the sources of the reagents and raw materials used in the following specific examples and comparative examples of the present invention are as follows: Unless otherwise specified, the raw materials are common commercially available products.
[0024] The testing methods used in the specific embodiments of the present invention and the comparative examples are as follows: Nuclear magnetic resonance analysis was performed using a Bruker AVANCE II 400 MHz spectrometer. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.
[0025] Example 1: Sodium pyrosulfate (222.1 g, 1.0 mol) and mercuric acetate (6.37 g, 0.02 mol) were mixed in 424.5 g of dichloromethane to obtain a mixed solution. 3-Bromopropionitrile (334.9 g, 2.5 mol) was then added dropwise to the mixed solution at 0°C for 3 hours. The mixture was then heated to 40°C and reacted for 4 hours. The reaction solution was filtered, and the dichloromethane and excess 3-Bromopropionitrile were removed by rotary evaporation to obtain a liquid product having the structure: ; The NMR analysis characterization is as follows: 1 H NMR (400 MHz, acetonitrile-d): 3.91 (t, 4h), 2.89 (t, 4h).
[0026] Example 2: Sodium pyroborate (201.2 g, 1.0 mol) and cuprous oxide (4.3 g, 0.03 mol) were mixed in 369.5 g of acetonitrile to obtain a mixed solution. 4-bromobenzonitrile (546.1 g, 3.0 mol) was then added dropwise to the mixed solution at 0°C for 4 hours. The mixture was then heated to 60°C and reacted for 5 hours. The reaction solution was filtered, and the acetonitrile and excess 4-bromobenzonitrile were removed by rotary evaporation to obtain a liquid product having the structure: ; The NMR analysis characterization is as follows: 1 H NMR (400 MHz, acetonitrile-d): 7.70 (d, 4h), 7.00 (d, 4h).
[0027] Example 3: Sodium pyrosulfate (222.1 g, 1.0 mol) and mercuric acetate (6.37 g, 0.02 mol) were mixed in 424.5 g of dichloromethane to obtain a mixed solution. 3-Bromopropionitrile (334.9 g, 2.5 mol) was then added dropwise to the mixed solution at 0°C for 3 hours. The mixture was then heated to 40°C and reacted for 4 hours. The reaction solution was filtered, and the dichloromethane and excess 3-Bromopropionitrile were removed by rotary evaporation to obtain a liquid product having the structure: ; The NMR analysis characterization is as follows: 1 H NMR (400 MHz, acetonitrile-d): 4.65 (t, 2h), 4.40 (t, 2h), 2.85 (m, 4h).
[0028] Example 4: Sodium pyrosulfate (222.1 g, 1.0 mol) and mercuric acetate (6.37 g, 0.02 mol) were mixed in 424.5 g of dichloromethane to obtain a mixed solution. 4-Bromobenzylpropionitrile (525.2 g, 2.5 mol) was then added dropwise to the mixed solution at 0°C for 3 hours. The mixture was then heated to 40°C and reacted for 4 hours. The reaction solution was filtered, and the dichloromethane and excess 4-Bromobenzylpropionitrile were removed by rotary evaporation to obtain a liquid product having the structure: ; The NMR analysis characterization is as follows: 1 H NMR (400 MHz, acetonitrile-d): 7.65 (m, 4h), 7.20 (m, 4h).
[0029] Example 5: Sodium pyroborate (201.2 g, 1.0 mol) and cuprous oxide (4.3 g, 0.03 mol) were mixed in 369.5 g of acetonitrile to obtain a mixed solution. 3-bromoacetonitrile (833.2 g, 3.0 mol) was then added dropwise to the mixed solution at 0°C for 4 hours. The mixture was then heated to 60°C and reacted for 5 hours. The reaction solution was filtered, and the acetonitrile and excess 3-bromoacetonitrile were removed by rotary evaporation to obtain a liquid product having the structure: ; The NMR analysis characterization is as follows: 1 H NMR (400 MHz, acetonitrile-d): 4.17 (t, 4h), 2.74 (t, 4h).
[0030] Comparative Example 1: The remaining technical solutions of this comparative example 1 are the same as those of Example 1, except that, in this comparative example 1, the addition of mercuric acetate is omitted; a liquid product is obtained, the structure of which is: .
[0031] Comparative Example 2: The remaining technical solutions of this comparative example 2 are the same as those of Example 2, except that, in this comparative example 2, the addition of cuprous oxide is omitted; a liquid product is obtained, the structure of which is: .
[0032] Comparative Example 3: The remaining technical solutions of this Comparative Example 3 are the same as those of Example 1, except that, in this Comparative Example 3, the dropping temperature of 3-bromopropionitrile is raised to 40° C.; a liquid product is obtained, the structure of which is: .
[0033] Comparative Example 4: The remaining technical solutions of this Comparative Example 4 are the same as those of Example 2, except that, in this Comparative Example 4, the dropping temperature of 4-bromobenzonitrile is raised to 60° C. to obtain a liquid product having the structure: .
[0034] Comparative Example 5: This Comparative Example 5 uses 1,3,6-hexanetrinitrile HTCN as the product.
[0035] The product purity and yield of Examples 1-5 and Comparative Examples 1-4 are shown in Table 1 below:
[0036] In order to further verify the application effects achieved by Examples 1-5 of the present application, the present application conducted the following application comparison experiments on the products provided in Examples 1-5 and Comparative Example 5: The soft-pack batteries corresponding to Examples 1-5 and Comparative Example 5 were prepared according to the following steps: Preparation of electrolyte: Prepared in a glove box with N2 atmosphere, the water content of the organic solvent system is less than 10ppm; the electrolyte includes: An organic solvent system with a mass fraction of 84.5%, specifically composed of ethylene carbonate EC:ethyl methyl carbonate EMC:dimethyl carbonate DMC in a mass ratio of 1:1:1 (wt%); The lithium salt system uses 1.0 mol·L -1 Lithium hexafluorophosphate LiPF6; The products provided in Examples 1-5 and Comparative Example 5 were respectively selected, and the mass fraction of the products in the electrolyte was 1%; The rest are other additives, specifically composed of ethylene carbonate VC: fluoroethylene carbonate FEC = 1:2 (wt%); The raw materials of the organic solvent system are mixed uniformly in a fixed ratio, and then refrigerated for 1.5-2 hours to obtain an organic solvent mixture; the lithium salt system is added and mixed uniformly, and finally the products provided in Examples 1-5 and Comparative Example 5 and other additives are added, mixed uniformly and set aside.
[0037] Preparation of the battery positive electrode: Using methyl pyrrolidone NMP as solvent, 2% of polyvinylidene fluoride (PVDF) is evenly dispersed to obtain a mixed solution. Then, 2% of carbon nanotubes (CNT) are added and mixed evenly. Then, 96% of the positive electrode active material (lithium cobalt oxide LiCoO2) is added and mixed evenly. The mixture is then evenly coated on aluminum foil using a coating machine. After drying, roller pressing and cutting, the positive electrode sheet is made. The surface density range is 350-450g / cm 2 (double-sided); Preparation of the battery negative electrode: Using deionized water as the solvent, evenly disperse 1% by mass of carboxymethyl cellulose (CMC) to obtain a mixed solution. Then, add 2% by mass of conductive carbon black SP and 96% by mass of negative electrode active material (specifically, vapor-deposited silicon carbon, material model SH-S02) and mix them evenly. Finally, add 1% by mass of styrene-butadiene rubber (SBR) and mix them evenly. After mixing evenly, use a coating machine to evenly coat the mixture on copper foil, dry it, roll it, and cut it into negative electrode sheets. The surface density range of the negative electrode sheets is 200-350g / cm. 2 (double-sided); Therefore, the following soft-pack batteries were obtained by assembling the electrolytes containing the products provided in Examples 1-5 and Comparative Example 5 as specific additives, and the amount of electrolyte used in each soft-pack battery was 25 g. The following performance comparison tests were then performed on each soft-pack battery: Three groups of soft-pack batteries corresponding to Examples 1-5 and Comparative Example 5 were prepared. Each group was cycled for 200 cycles at 25°C, 45°C, and 55°C. The charge and discharge conditions used in each cycle test were: a charge and discharge rate of 1C / 1C and a voltage range of 4.4V-4.8V. The measured lithium-ion battery capacity retention rate is shown in Table 2 below:
[0038] In order to further exert the effect of applying the nitrile functional group material to high-voltage lithium-ion batteries proposed in the above embodiment of the present application, the present embodiment also proposes a lithium-ion battery electrolyte based on the nitrile functional group material, including an organic solvent system, a lithium salt system and an additive system; the organic solvent system is composed of at least one carboxylate and at least one cyclic carbonate and / or chain carbonate; the lithium salt system includes any one or a mixture of lithium hexafluorophosphate LiPF6, lithium bis(fluorosulfonyl)imide LiFSI, lithium bis(trifluoromethylsulfonyl)imide LiTFSI, lithium bis(oxalatoborate) LiBOB and lithium tetrafluoroborate LiBF4; the additive system includes a nitrile functional group material, wherein the nitrile functional group material adopts the nitrile functional group material provided in the above embodiment of the present application.
[0039] Preferably, in this embodiment, the mass fraction of the organic solvent system in the lithium-ion battery electrolyte is 80%-92%, preferably 82.5%-87.5%; further preferably, in this embodiment, the mass fraction of the carboxylate in the lithium-ion battery electrolyte is 66%-80%; the mass fraction of the cyclic carbonate and / or the chain carbonate in the lithium-ion battery electrolyte is 7%-24%, more preferably 7.5%-21.5%; further preferably, in this embodiment, the carboxylate is ethyl acetate EA, ethyl propionate EP, or propyl propionate PP; the cyclic carbonate is ethylene carbonate EC or propylene carbonate PC; and the chain carbonate is dimethyl carbonate DMC, ethyl methyl carbonate EMC, or diethyl carbonate DEC.
[0040] Preferably, in this embodiment, the concentration of the lithium salt system in the lithium ion battery electrolyte is 0.8-1.0 mol·L -1 ; Preferably, in this embodiment, the mass fraction of the nitrile functional group-containing material in the lithium-ion battery electrolyte is 0.08%-3%, more preferably 0.1%-2%.
[0041] Preferably, in this embodiment, the additive system accounts for 0.5%-8% by mass of the lithium-ion battery electrolyte; the additive system further includes at least two of ethylene carbonate VC, fluoroethylene carbonate FEC, vinyl sulfate DTD, propane sultone PS, and methylene methanedisulfonate MMDS, accounting for 0.1%-5% by mass of the lithium-ion battery electrolyte.
[0042] This embodiment also proposes a method for preparing a lithium-ion battery electrolyte based on the above-mentioned nitrile functional group-containing material, wherein the raw materials of the organic solvent system are mixed to obtain an organic solvent mixture, the organic solvent mixture is frozen for 1-3 hours (preferably 1.5-2 hours), a lithium salt system is added to the organic solvent mixture and mixed, and finally an additive system is added and mixed to obtain a high-voltage lithium-ion battery electrolyte.
[0043] This embodiment also proposes a high-voltage lithium-ion battery, which uses the lithium-ion battery electrolyte based on the nitrile functional group-containing material described above; its positive electrode active material includes lithium cobalt oxide LiCoO2; and its negative electrode active material includes a carbon-silicon composite material.
[0044] In order to further verify the implementation effect of the high-voltage lithium-ion battery electrolyte proposed in the above embodiments of the present application, the present application further provides the following embodiments and comparative examples: Example 6: A high-voltage lithium-ion battery electrolyte, comprising: An organic solvent system with a mass fraction of 84.5%, specifically composed of ethyl propionate EP: propyl propionate PP: ethylene carbonate EMC = 3:5:2 (wt%); The lithium salt system uses 1.0 mol·L -1 Lithium hexafluorophosphate LiPF6; The product is provided by Example 1 with a mass fraction of 1%; The rest are other additives, specifically composed of ethylene carbonate VC: fluoroethylene carbonate FEC = 1:2 (wt%); The electrolyte was prepared in a glove box with an N2 atmosphere to ensure that the water content of the solvent system was less than 10 ppm. During the preparation, the raw materials of the organic solvent system were first mixed uniformly in a fixed ratio, and then refrigerated for 1.5-2 hours to obtain an organic solvent mixture; the lithium salt system was added and mixed uniformly, and finally the product provided in Example 1 and other additives were added, mixed uniformly and set aside.
[0045] Example 7: The rest of the technical solutions of Example 7 are the same as those of Example 6, except that, in Example 7, the product provided in Example 2 is used instead of the product provided in Example 1.
[0046] Example 8: The rest of the technical solutions of Example 8 are the same as those of Example 6, except that, in Example 8, the product provided in Example 3 is used instead of the product provided in Example 1.
[0047] Example 9: The rest of the technical solutions of Example 9 are the same as those of Example 6, except that, in Example 9, the product provided in Example 4 is used instead of the product provided in Example 1.
[0048] Example 10: The rest of the technical solutions of Example 10 are the same as those of Example 6, except that, in Example 10, the product provided in Example 5 is used instead of the product provided in Example 1.
[0049] Comparative Example 6: The remaining technical solutions of this Comparative Example 6 are the same as those of Example 6, except that, in this Comparative Example 6, the product provided in Comparative Example 5 is used instead of the product provided in Example 1.
[0050] Comparative Example 7: The rest of the technical solutions of this Comparative Example 7 are the same as those of Example 6, except that, in this Comparative Example 7, the organic solvent system is specifically composed of ethylene carbonate EC:ethyl propionate EP:fluoroethylene carbonate FEC=3:2:5 (wt%).
[0051] Comparative Example 8: The rest of the technical solutions of Comparative Example 8 are the same as those of Example 6, except that, in Comparative Example 8, the organic solvent system specifically consists of propylene carbonate PC: fluoroethylene carbonate FEC = 3:2 (wt%).
[0052] Comparative Example 9: The rest of the technical solutions of Comparative Example 9 are the same as those of Example 6, except that, in Comparative Example 9, the organic solvent system is specifically composed of ethyl propionate EP:propyl propionate PP:fluoroethylene carbonate FEC = 2:2:1 (wt%).
[0053] Then, the soft-pack batteries corresponding to Examples 6-10 and Comparative Examples 6-9 were prepared according to the following steps: Preparation of the battery positive electrode: Using methyl pyrrolidone NMP as solvent, 2% of polyvinylidene fluoride (PVDF) is evenly dispersed to obtain a mixed solution. Then, 2% of carbon nanotubes (CNT) are added and mixed evenly. Then, 96% of the positive electrode active material (lithium cobalt oxide LiCoO2) is added and mixed evenly. The mixture is then evenly coated on aluminum foil using a coating machine. After drying, roller pressing and cutting, the positive electrode sheet is made. The surface density range is 350-450g / cm 2 (double-sided); Preparation of the battery negative electrode: Using deionized water as the solvent, evenly disperse 1% by mass of carboxymethyl cellulose (CMC) to obtain a mixed solution. Then, add 2% by mass of conductive carbon black SP and 96% by mass of negative electrode active material (specifically, vapor-deposited silicon carbon, material model SH-S02) and mix them evenly. Finally, add 1% by mass of styrene-butadiene rubber (SBR) and mix them evenly. After mixing evenly, use a coating machine to evenly coat the mixture on copper foil, dry it, roll it, and cut it into negative electrode sheets. The surface density range of the negative electrode sheets is 200-350g / cm. 2 (double-sided); Therefore, the following soft-pack batteries were obtained by assembling the electrolytes containing the products provided in Examples 6-10 and Comparative Examples 6-9 respectively, with the amount of electrolyte used in each soft-pack battery being 25 g. The following performance comparison tests were then performed on the soft-pack batteries: Three groups of soft-pack batteries corresponding to Examples 6-10 and Comparative Examples 6-9 were prepared. Each group was cycled for 200 cycles at 25°C, 45°C, and 55°C. The charge and discharge conditions used in each cycle test were: a charge and discharge rate of 1C / 1C and a voltage range of 4.4V-4.8V. The measured lithium-ion battery capacity retention rate is shown in Table 3 below:
[0054] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.
[0055] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. A nitrile functional group-containing material, characterized in that Contains the following structural formula: ; where X is or ; Y is or ; R is a C2-C6 carbon chain cyano group or a benzonitrile group.
2. The nitrile functional group-containing material according to claim 1, wherein The nitrile functional group-containing material comprises the following structure: 、 、 and Any one or a mixture of several.
3. A nitrile functional group-containing material, characterized in that Contains the following structural formula: ; Wherein, R is a C2-C6 carbon chain cyano group or a benzonitrile group.
4. The nitrile functional group-containing material according to claim 3, wherein The nitrile functional group-containing material comprises the following structure: and / or .
5. A method for preparing a nitrile functional group-containing material according to claim 1 or 2, characterized in that: The following steps are involved: S11, mixing the pyrosulfate, the solvent, and the catalyst to obtain a mixed solution; S12, adding the bromonitrile organic compound and / or the iodonitrile organic compound dropwise to the mixed solution of step S11 under low temperature conditions; S13, after the dropwise addition is completed, the bromonitrile organic compound and / or the iodonitrile organic compound reacts with the pyrosulfate in the mixed solution under certain temperature conditions to obtain a reaction product; S14, after-treating the reaction product to obtain the nitrile functional group-containing material.
6. A method for preparing a nitrile functional group-containing material according to claim 3 or 4, characterized in that: The following steps are involved: S21, mixing the pyroborate, the solvent, and the catalyst to obtain a mixed solution; S22, adding the bromonitrile organic compound and / or the iodonitrile organic compound dropwise to the mixed solution of step S21 under low temperature conditions; S23, after the dropwise addition is completed, the bromonitrile organic compound and / or the iodonitrile organic compound reacts with the pyroborate in the mixed solution under certain temperature conditions to obtain a reaction product; S24, after-treating the reaction product to obtain the nitrile functional group-containing material.
7. The method for preparing a nitrile functional group-containing material according to claim 5 or 6, wherein: The pyrosulfate is sodium pyrosulfate and / or potassium pyrosulfate; the pyroborate is sodium pyroborate and / or potassium pyroborate; the bromononitrile organic compound is any one of 3-bromopropionitrile, 4-bromobutyronitrile, 5-bromovaleronitrile, 4-bromobenzonitrile and 4-bromophenylacetonitrile, or a mixture thereof; and / or the iodonium nitrile organic compound is 3-iodopropionitrile and / or 4-iodobutyronitrile; and / or the solvent is any one of dichloromethane, dichloroethane, ether, acetone, toluene, xylene, ethylbenzene, acetonitrile and water, or a mixture thereof; and / or the catalyst is any one of cuprous oxide, lead acetate, mercuric acetate and mercuric isooctanoate, or a mixture thereof.
8. The method for preparing a nitrile functional group-containing material according to claim 5 or 6, wherein: The amount of the bromononitrile organic compound and / or the iodononitrile organic compound added is 2.5-4.0 times, preferably 2.5-3.0 times, the molar amount of the corresponding pyrosulfate or pyroborate; and / or the amount of the catalyst added is 0.01-0.2 times, preferably 0.02-0.06 times, the molar amount of the corresponding pyrosulfate or pyroborate; and / or the amount of the solvent added is 2.0-5.0 times, preferably 2.0-3.0 times, the molar amount of the corresponding bromononitrile organic compound and / or the iodononitrile organic compound; and / or the low temperature conditions used for the dropwise addition are set to -10°C to 20°C, preferably -10°C to 0°C; and / or the temperature conditions of the reaction are set to 30-80°C, preferably 40-60°C, and the reaction time is 3-10 hours, preferably 4-6 hours.
9. An application of the nitrile functional group-containing material according to any one of claims 1 to 4, characterized in that: The nitrile functional group-containing material is added to the electrolyte of a lithium ion battery, wherein the addition amount of the nitrile functional group-containing material in the electrolyte is 0.05-5 wt %.
10. The use of the nitrile functional group-containing material according to claim 9, wherein The lithium-ion battery is a lithium cobalt oxide (LiCoO2) ion battery.