A benzene sulfonate additive and its application in sodium ion battery electrolyte
By adding benzenesulfonate additives to the sodium-ion battery electrolyte, a stable SEI film is formed, which solves the performance shortcomings of sodium-ion battery electrolyte and achieves improved battery performance with high safety and long cycle life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGDONG JUSHI CHEM CO LTD
- Filing Date
- 2024-12-12
- Publication Date
- 2026-07-03
AI Technical Summary
Existing sodium-ion battery electrolytes suffer from problems such as easy gas generation during cycling, poor high and low temperature performance, and short cycle life. Furthermore, the use of multiple additives may lead to incompatibility, affecting battery performance.
By using benzene sulfonate additives, 0.1% to 10% of benzene sulfonate additives are added to the electrolyte of sodium-ion batteries to form a stable inorganic solid electrolyte interface film (SEI film), thereby improving the battery's overcharge protection and oxidation stability.
It improves the high voltage resistance, operating temperature range and safety of sodium-ion batteries, and extends cycle life, making it suitable for the promotion and application of low-cost and high-safety sodium-ion secondary batteries in the energy storage field.
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Figure CN119708043B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery electrolyte additives, and in particular to a benzenesulfonate ester additive and its application in sodium-ion battery electrolytes. Background Technology
[0002] Since their commercialization, lithium-ion batteries have been widely used in electronics, communications, military aerospace, and electric vehicles. However, the low reserves and uneven distribution of lithium resources have led to high costs associated with lithium mining, thus limiting the development of the new energy industry. In contrast, sodium is abundant and evenly distributed in the Earth's crust. Therefore, developing sodium-ion batteries as energy storage devices offers advantages such as low cost and high sustainability. Lithium and sodium belong to the same group of elements, possessing similar physicochemical properties. Furthermore, sodium-ion batteries and lithium-ion batteries share similar working principles and highly similar manufacturing processes. Therefore, developing high-performance sodium-ion batteries has promising application prospects and is expected to replace lead-acid and lithium-ion batteries in some applications in the future, thereby supporting the sustainable development of large-scale energy storage technology.
[0003] Sodium-ion battery cathode and anode materials have been extensively developed and explored, and their capacity is now comparable to that of lithium-ion batteries. However, the matching electrolyte system is still under investigation. Optimizing sodium salts, solvents, and introducing functional additives can effectively improve sodium-ion battery electrolytes. However, the types of sodium salts are limited, restricting their improvement potential, and they are also costly. Optimizing new solvents involves long development cycles, large investments, and high production costs, resulting in poor cost-effectiveness. Introducing functional additives, on the other hand, requires less dosage, significantly improves performance, and offers advantages such as low cost and good economics. Therefore, developing novel electrolyte additives is of great significance to the development of sodium-ion batteries.
[0004] Currently, reported electrolyte additives for sodium-ion batteries include vinyl sulfite (ES), succinate (SN), and vinylene carbonate (VC). However, these additives offer limited performance improvement for sodium-ion batteries, exhibiting problems such as easy gas generation during cycling, poor high and low temperature performance, and short cycle life. Therefore, designing appropriate additive molecules can preferentially decompose to form a uniform and stable SEI film, thereby significantly improving the electrochemical performance of sodium-ion batteries. Studies have shown that introducing aromatic ring groups into the electrolyte can effectively suppress overcharging; sulfonate groups can improve the ionic conductivity of the electrolyte, which is beneficial for constructing a low-resistance SEI film, thus achieving high-rate performance and long-cycle stability. However, using multiple additives together may lead to incompatibility, which could negatively impact battery performance.
[0005] To address the aforementioned issues, there is an urgent need to design a benzenesulfonate-based electrolyte additive to improve the properties of sodium-ion battery electrolytes, thereby enabling the construction of sodium-ion batteries with a wide temperature range, long lifespan, and high rate. Summary of the Invention
[0006] To address the aforementioned technical problems, this invention provides a benzenesulfonate additive and its application in sodium-ion battery electrolytes.
[0007] To achieve the above objectives, the present invention is implemented according to the following technical solution:
[0008] One objective of this invention is to provide a benzenesulfonate additive, which is a compound with the structural formula shown in formula (I):
[0009]
[0010] Among them: R1, R2, R3, R4 and R5 are one of the following: hydrogen atoms, fluorine atoms or carbon atoms in fluorinated alkane or fluorinated ether groups with 1 to 3 carbon atoms;
[0011] R6 is one of the following groups: alkanes, fluorinated alkanes, cyanoalkyl alkanes, and silane groups, which have 1 to 5 carbon atoms.
[0012] Furthermore, R1, R2, R3, R4, and R5 are one of the following groups:
[0013]
[0014] R6 is one of the following groups:
[0015]
[0016] Preferably, the benzenesulfonate additive is one of the following compounds 1 to 52:
[0017]
[0018]
[0019] A second objective of this invention is to provide an application of benzenesulfonate additives in sodium-ion battery electrolytes.
[0020] Specifically, the sodium-ion battery electrolyte contains 0.1% to 10% by volume of benzenesulfonate additives.
[0021] Compared with existing technologies, the phenyl groups in the benzene sulfonate electrolyte additives of this invention can improve the overcharge protection performance of the battery, and the sulfonate groups can form a stable inorganic SEI film and improve oxidation stability. When used as an additive in sodium-ion battery electrolytes, it can not only effectively improve the battery's high voltage resistance, operating temperature range, safety, and cycle stability, but also promote the application of low-cost, high-safety, and long-cycle sodium-ion secondary batteries in the energy storage field, thus solving many performance shortcomings of existing sodium-ion secondary battery electrolytes. The synthesis method of the phenyl sulfonate molecules of this invention is simple, safe to operate, and produces high-purity products. At the same time, it exhibits excellent performance in sodium-ion secondary batteries and is suitable for widespread application. Attached Figure Description
[0022] Figure 1 The graph shows the electrochemical performance of NFPP||Na batteries at room temperature in EDF and EDFM electrolytes.
[0023] Figure 2 The graph shows the electrochemical performance of the NFPP||Na battery at 55℃ in Baseline and BEN electrolytes.
[0024] Figure 3 The graph shows the long-cycle performance of NFPP||Na batteries in ED and EDM electrolytes at -20℃.
[0025] Figure 4 The graph shows the rate performance of NFPP||Na batteries at room temperature in PF and PFM electrolytes.
[0026] Figure 5 The graph shows the long-cycle performance of NFPP||Na batteries at high rate and room temperature in NPF and NPFM electrolytes.
[0027] Figure 6 The graph shows the long-cycle performance of NFPP||HC batteries in TEMS electrolyte.
[0028] The above Figures 1-6 The symbols “△” and “○” in the diagram represent the coulombic efficiency of the battery, while the symbols “▲” and “●” represent the battery capacity. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.
[0030] Unless otherwise specified, all raw materials and reagents used in the following examples are commercially available; and the following examples use several typical compounds as sulfonamide / ester electrolyte additives.
[0031] Example 1
[0032] Trimethylchlorosilane (TMSCl) was slowly added dropwise to a tetrahydrofuran (THF) solution of 4-fluoromethylbenzenesulfonic acid at 0 °C and reacted for 4-6 h. After the reaction was completed, the THF solvent was removed by rotary evaporation, and the crude product was obtained. The crude product was purified by vacuum distillation and recrystallization to finally obtain compound 1 with high purity.
[0033] The reaction formula is as follows:
[0034]
[0035] Example 2
[0036] Trimethylchlorosilane (TMSCl) was slowly added dropwise to a tetrahydrofuran (THF) solution of benzenesulfonic acid at 0 °C and reacted for 4-6 h. After the reaction was completed, the THF solvent was removed by rotary evaporation, and the crude product was obtained. The crude product was purified by vacuum distillation and recrystallization to finally obtain compound 9 with high purity.
[0037] The reaction formula is as follows:
[0038]
[0039] Example 3
[0040] Fluoroacetonitrile was slowly added dropwise to a tetrahydrofuran (THF) solution of benzenesulfonic acid at 0℃ and reacted for 4-6 hours. After the reaction was completed, the THF solvent was removed by rotary evaporation, and the crude product was obtained. The crude product was purified by vacuum distillation and recrystallization to finally obtain compound 19 with high purity.
[0041] The reaction formula is as follows:
[0042]
[0043] Example 4
[0044] Trifluoromethanol was slowly added dropwise to a tetrahydrofuran (THF) solution of benzenesulfonic acid at 0°C and reacted for 4-6 hours. After the reaction was completed, the THF solvent was removed by rotary evaporation, and the crude product was obtained. The crude product was purified by vacuum distillation and recrystallization to finally obtain compound 28 with high purity.
[0045] The reaction formula is as follows:
[0046]
[0047] Example 5
[0048] Trifluoroethanol was slowly added dropwise to a tetrahydrofuran (THF) solution of 4-trifluoromethylbenzenesulfonic acid at 0℃ and the reaction was carried out for 4-6 hours. After the reaction was completed, the THF solvent was removed by rotary evaporation, and then the crude product was obtained. The crude product was purified by vacuum distillation and recrystallization to finally obtain compound 35 with high purity.
[0049] The reaction formula is as follows:
[0050]
[0051] Test case
[0052] Exemplary examples show that electrolytes for sodium-ion batteries were prepared using high-purity compounds 1, 9, 19, 28, and 35 prepared in Examples 1-5, respectively:
[0053] Electrolyte containing high-purity compound 1
[0054] 1) In a glove box at 25°C with both water and oxygen content below 0.01 ppm, 0.168 g of sodium hexafluorophosphate was weighed and dissolved in 1 mL of a solution of ethylene carbonate, diethyl carbonate, and fluoroethylene carbonate (2:2:1 by vol.). The solution was stirred overnight to ensure complete dissolution, yielding a solution with a concentration of 1 mol / L. -1 The basic electrolyte for sodium-ion batteries (denoted as EDF).
[0055] 2) In a glove box at 25°C with water and oxygen content both below 0.01 ppm, take 20 μL of compound 1 and mix it with 1 mL of 1 mol / L sodium ion battery electrolyte (EDF). The electrolyte is denoted as EDFM.
[0056] Electrolyte containing high-purity compound 9
[0057] 1) In a glove box at 25°C with water and oxygen content both below 0.01 ppm, 0.168 g of sodium hexafluorophosphate was weighed and dissolved in 1 mL of a solution of ethylene carbonate, propylene carbonate, diethyl carbonate, and fluoroethylene carbonate (6:6:6:1 by vol.). The solution was stirred overnight to ensure complete dissolution, thus preparing a sodium-ion battery electrolyte with a concentration of 1 mol / L (denoted as Baseline).
[0058] 2) In a glove box at 25°C with water and oxygen content both below 0.01 ppm, take 10 μL of compound 9 and mix it with 1 mL of 1 mol / L sodium ion battery electrolyte (Baseline). The electrolyte is denoted as BEN.
[0059] Electrolyte containing high-purity compound 19
[0060] 1) In a glove box at 25°C with water and oxygen content both below 0.01 ppm, 0.168 g of sodium hexafluorophosphate was weighed and dissolved in 1 mL of a propylene carbonate and fluoroethylene carbonate (19:1 by vol.) solution and stirred overnight to ensure complete dissolution, thus preparing a sodium-ion battery electrolyte (denoted as ED) with a concentration of 1 mol / L.
[0061] 2) In a glove box at 25°C with water and oxygen content both below 0.01 ppm, take 10 μL of compound 19 and mix it with 1 mL of 1 mol / L sodium ion battery electrolyte (Baseline). The electrolyte is denoted as EDM.
[0062] Electrolyte containing high-purity compound 28
[0063] 1) In a glove box at 25°C with both water and oxygen content below 0.01 ppm, 0.1224 g of sodium perchlorate was weighed and dissolved in 1 mL of a propylene carbonate and fluoroethylene carbonate (9:1 by vol.) solution. The solution was stirred overnight to ensure complete dissolution and homogeneity, yielding a solution with a concentration of 1 mol / L. -1 Sodium-ion battery electrolyte (denoted as PF).
[0064] 2) In a glove box at 25°C with water and oxygen content both below 0.01 ppm, take 5 μL of compound 28 and mix it with 1 mL of 1 mol / L sodium ion battery electrolyte (PF). The electrolyte is denoted as PFM.
[0065] Electrolyte containing high-purity compound 35
[0066] 1) In a glove box at 25°C with water and oxygen content both below 0.01 ppm, 0.1224 g of sodium perchlorate was weighed and dissolved in 1 mL of a propylene carbonate and fluoroethylene carbonate (19:1 by vol.) solution and stirred overnight to ensure complete dissolution and uniform mixing, thus preparing a sodium-ion battery electrolyte (denoted as NPF) with a concentration of 1 mol / L.
[0067] 2) In a glove box at 25°C with water and oxygen content both below 0.01 ppm, take 20 μL of compound 35 and mix it with 1 mL of 1 mol / L sodium ion battery electrolyte (NPF). The electrolyte is denoted as NPFM.
[0068] Preparation of NFPP electrode sheets: Sodium iron pyrophosphate (NFPP) was used as the positive electrode material. NFPP, acetylene black, and PVDF binder were mixed at a mass ratio of 8:1:1 and dispersed in N-methylpyrrolidone (NMP) to prepare a slurry. The slurry was then transferred to a vacuum degassing machine and stirred to obtain a uniform slurry. The slurry was then uniformly coated onto aluminum foil using a 100μm scraper and vacuum dried at 80℃ for 12h. The coated aluminum foil was then cut into electrode sheets with a diameter of 12mm using a cutting machine and stored in a glove box.
[0069] The hard carbon (HC) electrode was prepared by dispersing HC, SuperP, and PVDF binder in an NMP ratio of 8:1:1. After stirring, a uniform slurry was obtained and uniformly coated onto aluminum foil using a 50μm scraper. The slurry was then vacuum dried at 80℃ for 12h and cut into electrode sheets with a diameter of 12mm. The sheets were then stored in a glove box.
[0070] In a glove box, the prepared NFPP electrode sheet was used as the positive electrode; the HC electrode sheet and a sodium sheet with a diameter of 14 mm were used as the negative electrodes; glass fiber was used as the separator; EDFM, BEN, DEM, PFM, NPFM, and EMS electrolytes prepared using sodium electrolytes (EDF, Baseline, ED, PF, and NPF) and high-purity compounds 1, 9, 19, 28, and 35 as electrolyte additives were used to assemble NFPP||Na, HC||Na, and NFPP||HC sodium-ion pouch batteries, respectively. Test data were obtained using an electrochemical testing system at temperatures ranging from -20℃ to 55℃.
[0071] Electrochemical performance tests were conducted on the prepared batteries. NFPP||Na and NFPP||HC batteries were assembled using different electrolyte systems within different temperature ranges (-20℃ to 55℃) with NFPP as the positive electrode and HC and sodium metal as the negative electrode. Their rate performance and cycle stability were then tested.
[0072] NFPP||Na batteries were assembled using EDF and EDFM electrolytes under conditions of 25℃, 4V high voltage, and 5C discharge rate. The specific capacity and coulombic efficiency of the batteries were then tested, and the results are as follows: Figure 1 As shown in (a) in the figure, and through Figure 1 (b) and (c) in the figure show the charge-discharge curves of NFPP||Na batteries assembled with the two electrolyte systems.
[0073] from Figure 1 (a) and Figure 1 As can be seen in (b), the NFPP||Na battery using basic electrolyte (EDF) experienced overcharging after 1077 cycles, resulting in a short circuit. Figure 1 (a) and Figure 1 As can be seen in (c), the EDFM electrolyte with compound 1 added to the basic electrolyte (EDF) can stably cycle for 5000 cycles with the NFPP||Na battery using this electrolyte. The capacity retention rate after cycling is as high as 91.86%, and the average coulombic efficiency reaches 99.97%.
[0074] Furthermore, the specific capacity and coulombic efficiency of NFPP||Na batteries with Baseline and BEN electrolyte systems were tested under conditions of 55℃, 4V high voltage, and 0.5C discharge rate. The results are as follows: Figure 2 As shown in (a) in the figure, and through Figure 2 (b) and (c) in the figure show the charge-discharge curves of NFPP||Na batteries assembled with the two electrolyte systems.
[0075] from Figure 2 (a) and Figure 2 As can be seen in (b), the NFPP||Na battery using Baseline electrolyte experienced overcharging after 470 cycles, resulting in a short circuit. Figure 2 (a) and Figure 2 As can be seen from (c), the NFPP||Na battery using BEN electrolyte still has good cycle stability at a high temperature of 55℃, and the capacity retention rate is as high as 88.23% after 2000 cycles.
[0076] Furthermore, the specific capacity and coulombic efficiency of NFPP||Na batteries with ED and EDM electrolyte systems were tested under conditions of -20℃, 4V high voltage, and 0.5C discharge rate. The results are as follows: Figure 3 As shown.
[0077] from Figure 3 It can be seen that the NFPP||Na battery using EDM electrolyte retains 100% capacity after 400 cycles under extreme conditions of -20℃, with almost no capacity decay. At the same time, the average coulombic efficiency reaches 99.95%, demonstrating excellent cycle stability, which is significantly better than the NFPP||Na battery using ED electrolyte.
[0078] The specific capacity of NFPP||Na batteries with PF and PFM electrolyte systems was tested under conditions of 25℃ and 4V high voltage, respectively. The results are as follows: Figure 4 As shown in Table 1.
[0079] Table 1 Electrochemical performance of NFPP||Na batteries in different electrolytes
[0080]
[0081]
[0082] from Figure 4 As can be seen from the data in Table 1, the discharge specific capacity of the PF electrolyte battery is lower than that of the PFM electrolyte battery at different rates. Furthermore, the PFM electrolyte system still has a considerable specific capacity at a super-high rate of 100C, while the PF electrolyte system cannot continue to release a high specific capacity at a high rate of 100C. This fully demonstrates that the NFPP||Na battery assembled with compound 28 as an electrolyte additive has good rate performance.
[0083] The specific capacity of NFPP||Na batteries with NPF and NPFM electrolyte systems was tested under the conditions of 25℃, 4V high voltage, and 20C discharge rate. The results are as follows: Figure 5 As shown.
[0084] from Figure 5 It can be seen that the battery with NPFM electrolyte can stably cycle 10,000 times with a capacity retention of 74.1% and an average coulombic efficiency of 99.81%, while the specific capacity of the NPF battery is very low after 6,000 cycles. This shows that the NPFM system still exhibits excellent cycle stability at high rates.
[0085] The specific capacity and coulombic efficiency of the NFPP||HC sodium-ion pouch cell with TEMS electrolyte system were tested under conditions of 3.65V voltage and 1C discharge rate. The results are as follows: Figure 6 As shown.
[0086] from Figure 6 It can be seen that under the conditions of 3.65V voltage and 1C rate, the NFPP||HC pouch cell with TEMS electrolyte exhibits excellent cycle stability, and still has 81.57% capacity retention after 500 cycles. This indicates that BEN electrolyte improves the interfacial conditions and reduces the side reactions between the positive and negative electrodes, thereby enabling rapid ion conduction and giving it good electrochemical performance.
[0087] In summary, the phenyl groups in the benzenesulfonate electrolyte additives of this invention improve overcharge protection, while the sulfonate groups can form a stable inorganic SEI film and improve oxidation stability. Using these additives in sodium-ion battery electrolytes not only effectively improves the battery's high-voltage resistance, operating temperature range, safety, and cycle stability, but also promotes the widespread application of low-cost, high-safety, and long-cycle sodium-ion secondary batteries in the energy storage field, thus solving many performance shortcomings of existing sodium-ion secondary battery electrolytes.
[0088] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.
Claims
1. The application of a benzenesulfonate additive in sodium-ion battery electrolyte, characterized in that: The sodium-ion battery electrolyte contains 0.1% to 10% by volume of a benzenesulfonate additive; the benzenesulfonate additive is one of the following compounds: 。