Tannin TA beta nucleating agent doped gel electrolyte, preparation method and application

Abstract

The present application relates to the technical field of energy storage materials, and specifically discloses a tannic acid TA beta nucleating agent doped gel electrolyte, a preparation method and application. The gel electrolyte prepared by in-situ polymerization technology through radiation in the present application effectively improves the problem of complex preparation process of the gel electrolyte. The lithium ion battery using the gel electrolyte not only has a significant improvement in energy density and cycle life, but also can maintain stable electrochemical performance. The high free radical capture and consumption characteristics improve the capacity retention capability of the battery under high voltage and high rate conditions, and the obtained gel electrolyte battery has a discharge specific capacity of about 169 mAh / g under 5C conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage materials, and specifically discloses a tannic acid TA@β nucleating agent doped gel electrolyte, a preparation method thereof, and an application thereof. Technical Background

[0002] With the continuous growth of energy demand in modern society and the pursuit of environmentally friendly energy solutions, lithium-ion batteries have become the preferred energy source for portable electronic devices, electric vehicles, and large-scale energy storage systems due to their advantages such as high energy density, long cycle life, and low self-discharge rate. However, traditional lithium-ion batteries have some limitations, such as the flammability, volatility, and poor thermal stability of the electrolyte, which limit the further improvement of battery performance and the expansion of the application scope.

[0003] Gel electrolytes combine the high safety of solid electrolytes and the high ionic conductivity of liquid electrolytes, and are expected to become the key materials for next-generation lithium-ion batteries. Although many literatures (Ma, Chao, et al. InfoMat. 2022, 002, 004; Nan Chen, et al. Adv, Energy Mater, 2018, 8, 12; Shuai Tang, Wei Guo, et al. Adv, Energy Mater, 2020, 11, 2) and patents (Chinese invention patent CN118344353A; Chinese invention patent CN118146447A) report that gel electrolytes show great potential in terms of safety and electrochemical performance, they still face some challenges in practical applications. For example, the preparation process of gel electrolytes is complex, and under harsh conditions such as high rate, high voltage, and high temperature in the battery, there are many side reactions between the internal electrolyte and the electrode, resulting in a sharp decline in the cycle stability of the battery and other problems.

[0004] Therefore, it is necessary to seek a gel electrolyte with excellent performance to overcome the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to develop a method of γ-ray or electron beam for synthesizing a novel gel electrolyte (TA@β-x / GPE-y) composite material doped with tannic acid @β nucleating agent (TA@β-x represents the mass of tannic acid @β nucleating agent, GPE-y represents the gel fraction, where 0 < x < 20, 0 < y < 60%), and in-situ polymerize the composite material inside a lithium battery as an electrolyte for isolating the electron transmission of lithium ions.

[0006] The technical solution adopted by the present invention is as follows:

[0007] In the first aspect, the present invention provides a preparation method of a TA@β nucleating agent doped gel electrolyte, including the following steps:

[0008] S1: Weigh tannic acid (TA) and β-nucleating agent in a mass ratio of 1:5 to 5:1, then mix them in water, stir at room temperature until fully reacted, and then separate, purify, and dry to obtain TA@β free radical scavenger;

[0009] S2: Add the free radical scavenger obtained in step S1, as well as the phosphate ester monomer and the acrylate monomer to the lithium salt electrolyte and stir to mix well; the amounts added are 1 to 100 parts by mass for the free radical scavenger and 200 to 600 parts by mass for both the phosphate ester monomer and the acrylate monomer.

[0010] The lithium salt is one or a mixture of two or more of lithium hexafluorophosphate, lithium dioxalatoborate, lithium tetrafluoroborate, lithium bis(difluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide; the phosphate ester monomer is one or a mixture of two or more of di[2-(methacryloyloxy)ethyl]phosphate, di[2-(acryloyloxy)ethyl]phosphate, dimethyl vinyl phosphate, diethyl vinyl phosphate, dipropyl vinyl phosphate, and 2-(methacryloyloxy)ethyl-2-(trimethylamino)ethyl phosphate; and the acrylate monomer is one or a mixture of two or more of trimethylolpropane triacrylate, cyanuric acid triacrylate, pentaerythritol tetraacrylate, and 1,6-hexanediol diacrylate.

[0011] S3: Irradiate the mixed solution obtained in step S2 using gamma rays or an electron beam; after irradiation, a novel gel electrolyte is obtained.

[0012] Preferably, in step S1, the reaction time at room temperature with stirring is 1-10 days.

[0013] Preferably, in step S1, the concentration of tannic acid is 5–50 g / L.

[0014] Preferably, in step S2, the mass concentration of the free radical scavenger is 0.1–10 g / L, and the mass concentrations of the phosphate ester monomer and the acrylate monomer are 20–60 g / L and 20–60 g / L, respectively.

[0015] Furthermore, in step S2, the stirring time is 0.1-48 hours.

[0016] Preferably, in step S3, the irradiation absorbed dose rate is 10-150 Gy / min, and the absorbed dose is 0.1-20 kGy.

[0017] Preferably, in step S3, the radiation source that generates γ rays is... 60 Co source or 137 Cs source; the electron beam is generated by an electron accelerator with an energy of 0.1–10 MeV.

[0018] Secondly, the present invention provides the TA@β-doped gel electrolyte described in the first aspect.

[0019] Thirdly, the present invention provides an application of the second aspect in a TA@β-doped gel electrolyte lithium-ion battery.

[0020] A novel gel-type lithium battery was synthesized by adding TA@β free radical scavenger, phosphate ester monomers, and acrylate monomers to a lithium salt electrolyte, stirring and mixing, and then injecting the mixture into a lithium-ion battery. The battery was then synthesized by in-situ polymerization using γ-rays or electron beams.

[0021] Fourthly, the present invention provides a lithium-ion battery, wherein the lithium-ion battery uses the TA@β-doped gel electrolyte described in the first aspect as an electrolyte.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1) Currently, lithium-ion batteries aim for higher energy density. Adding comonomers with high-voltage resistance to the electrolyte creates a gel framework that can adapt to a higher voltage range, effectively improving the energy density of gel-type batteries. Simultaneously, flame-retardant phosphate ester compounds can mitigate / inhibit thermal runaway at high energy densities, significantly enhancing the longevity of lithium-ion batteries.

[0024] 2) Under high energy density conditions, efficient charge-discharge capability can significantly expand the application range of batteries. Adding specially designed free radical scavenging additives to the gel electrolyte can significantly slow down / inhibit battery side reactions under high energy density conditions, enabling the battery to maintain excellent capacity retention at higher rate conditions and meet the requirements of efficient charge-discharge capability.

[0025] 3) Gel electrolytes can be synthesized using gamma rays or electron beams. This method has near-zero activation energy, resulting in relatively mild reaction conditions that can be completed at room temperature. Furthermore, the process requires no additional initiators, ensuring high product purity. Simultaneously, the reaction rate and extent of the monomers can be altered by adjusting the distance between the sample and the radiation source, as well as the irradiation time, leading to in-situ formation of gel-type batteries. Attached Figure Description

[0026] Figure 1 Infrared spectrum of tannic acid combined with β-nucleating agent.

[0027] The horizontal axis represents wavenumber, in cm. -1 The vertical axis represents transmittance, in percentage. I, II, and III represent TA, β nucleating agent, and TA@β, respectively.

[0028] Figure 2UV absorption spectrum of DPPH· solution after reaction with TA and TA@β.

[0029] The horizontal axis represents wavelength in nm, and the vertical axis represents absorbance.

[0030] Figure 3 Nuclear magnetic resonance (NMR) C-index spectra of radiation-synthesized gel electrolytes. The horizontal axis represents chemical shift in ppm, and the vertical axis represents intensity.

[0031] Figure 4 Voltage-capacity curves of TA@β-doped novel gel electrolyte batteries under 3-4.8V, 5C conditions.

[0032] The horizontal axis represents specific capacity in mAh / g, and the vertical axis represents voltage in V. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0036] Example 1

[0037] A novel TA@β-doped gel electrolyte composite material for high-energy-density lithium batteries is prepared by the following method:

[0038] 1) Add 1g of tannic acid (TA) and 1g of β-nucleating agent to a container containing 100mL of deionized water. Mix the mixture with sonication and stir for 1 day. After the reaction is complete, filter the white particles in the container, wash them with distilled water and ethanol repeatedly with sonication, and dry them in a vacuum oven at 60℃ for later use. The resulting particles are named TA@β free radical scavenger.

[0039] 2) In a reaction vessel containing 10 mL of 1 mol LiPF6 electrolyte solvent, 0.2 g of diethyl vinyl phosphate monomer, 0.3 g of pentaerythritol tetraacrylate monomer, and 20 mg of the TA@β free radical scavenger obtained in step 1) were stirred for 30 minutes to mix thoroughly. After mixing, the mixture was sent to a cobalt source chamber for γ-irradiation at a dose rate of 40 Gy / min and an absorbed dose of 2 kGy. The resulting product was named TA@β-x / GPE-y, where x = 20 and y = 30% (x represents the mass of TA@β free radical scavenger, and y represents the gel fraction of the gel electrolyte).

[0040] The tannic acid (TA) composite β-nucleating agent material prepared in this invention was characterized by infrared spectroscopy, and the results are as follows: Figure 1 As shown, I is the infrared spectrum of tannic acid (TA), II is the infrared spectrum of the β-nucleating agent, and III is the infrared spectrum of TA@β. It can be clearly seen that at 1650 cm⁻¹... -1 The carbon-carbon double bond peak of tannic acid (TA) appeared in the infrared spectrum of TA@β, confirming the successful preparation of the composite material. Further characterization of the composite gel's C10 NMR spectrum was performed, as shown in... Figure 2 The C-spectral peak shown corresponds perfectly to the drawn gel structure, proving the successful preparation of this composite gel material. Simultaneously, to verify whether TA@β possesses free radical scavenging ability, the UV absorption spectrum of the DPPH solution after the reaction of tannic acid (TA) and TA@β was measured. Figure 3 As shown, the DPPH solution has a significant peak at a wavenumber of 522 nm. When tannic acid (TA) is added, the same peak disappears. Similarly, the peak of the DPPH solution with added TA@β also disappears. This fully demonstrates that the composite material has excellent free radical scavenging ability.

[0041] Performance Study of TA@β-Doped Novel Gel Electrolyte in Lithium-ion Batteries

[0042] The electrolyte obtained in Example 1, containing 20 mg of TA@β free radical scavenger, 0.2 g of diethyl vinyl phosphate monomer and 0.3 g of pentaerythritol tetraacrylate monomer, was injected into a lithium battery with lithium nickel cobalt manganese oxide as the positive electrode, lithium sheet as the negative electrode and Celgard 2035 separator. The encapsulated battery was then irradiated with gamma rays or electron beams. Finally, the electrochemical performance of the irradiated gel battery was tested using the Wuhan Landian charge / discharge system.

[0043] The novel TA@β-doped gel electrolyte battery was tested at 3-4.8V and 5C. Figure 4 The horizontal axis represents specific capacity in mAh / g, and the vertical axis represents voltage in V. It is clear that under high voltage and high rate conditions, gel batteries containing free radical scavengers exhibit excellent charge and discharge capabilities.

[0044] Example 2

[0045] In step 2 of embodiment 1 60 The Co-γ rays were replaced with an electron beam generated by an electron accelerator, with an absorbed dose rate of 40 kGy / min and an absorbed dose of 2 kGy. Other conditions were the same as in Example 1, resulting in a TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 30%.

[0046] Example 3

[0047] The absorbed dose rate in step 2) of Example 1 was changed to 60 Gy / min, and other conditions were the same as in Example 1, to obtain the TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 29%.

[0048] Example 4

[0049] The absorbed dose rate in step 2) of Example 1 was changed to 80 Gy / min, and other conditions were the same as in Example 1, to obtain the TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 27%.

[0050] Example 5

[0051] The absorbed dose rate in step 2) of Example 1 was changed to 100 Gy / min, and other conditions were the same as in Example 1, to obtain the TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 25%.

[0052] Example 6

[0053] The absorbed dose rate in step 2) of Example 1 was changed to 120 Gy / min, and other conditions were the same as in Example 1, to obtain the TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 21%.

[0054] Example 7

[0055] The absorbed dose in step 2) of Example 1 was changed to 4 kGy, and other conditions were the same as in Example 1, to obtain the TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 33%.

[0056] Example 8

[0057] The absorbed dose in step 2) of Example 1 was changed to 6 kGy, and other conditions were the same as in Example 1, to obtain TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 38%.

[0058] Example 9

[0059] The absorbed dose in step 2) of Example 1 was changed to 8 kGy, and other conditions were the same as in Example 1, to obtain the TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 47%.

[0060] Example 10

[0061] The absorbed dose in step 2) of Example 1 was changed to 10 kGy, and other conditions were the same as in Example 1, to obtain TA@β-x / GPE-y gel composite material for lithium batteries, where x = 20 and y = 60%.

[0062] Example 11

[0063] The free radical scavenger in step 2) of Example 1 was changed to 1 mg, and other conditions were the same as in Example 1, to obtain TA@β-x / GPE-y gel composite material for lithium batteries, where x = 1 and y = 30%.

[0064] Example 12

[0065] The free radical scavenger in step 2) of Example 1 was changed to 5 mg, and other conditions were the same as in Example 1, to obtain TA@β-x / GPE-y gel composite material for lithium batteries, where x = 5 and y = 30%.

[0066] Example 13

[0067] The free radical scavenger in step 2) of Example 1 was changed to 10 mg, and other conditions were the same as in Example 1, to obtain TA@β-x / GPE-y gel composite material for lithium batteries, where x = 10 and y = 30%.

[0068] Example 14

[0069] The free radical scavenger in step 2) of Example 1 was changed to 30 mg, and other conditions were the same as in Example 1, to obtain TA@β-x / GPE-y gel composite material for lithium batteries, where x = 30 and y = 30%.

[0070] Example 15

[0071] The free radical scavenger in step 2) of Example 1 was changed to 40 mg, and other conditions were the same as in Example 1, to obtain TA@β-x / GPE-y gel composite material for lithium batteries, where x = 40 and y = 30%.

[0072] Test Results

[0073] The specific capacity of the TA@β-x / GPE-y gel electrolyte assembled batteries prepared in Examples 2-15 was tested at 5C according to the methods and test conditions described in Example 1. The results are recorded in Table 1 along with the test results of Example 1.

[0074] Table 1. Electrolyte performance test results of TA@β-x / GPE-y gels prepared in Examples 1-15

[0075]

[0076] As shown in Table 1, when the TA@β-x / GPE-y gel material prepared in the embodiments of the present invention is used in lithium batteries, the TA@β-x / GPE-y gel can suppress the side reactions generated by the internal electrolyte and electrodes under the harsh conditions of high voltage and high rate, and further improve the cycle stability of the battery.

[0077] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Those skilled in the art can make various modifications to the technical solutions in the embodiments based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations. Any modifications, variations, substitutions, etc., made based on the technical content disclosed in this invention are equivalent to equivalent implementations and should be included within the protection scope of this invention.

Claims

1. A method for preparing a tannic acid (TA@β) nucleating agent-doped gel electrolyte, characterized in that, The steps include the following: S1: Weigh tannic acid (TA) and β-nucleating agent in a mass ratio of 1:5 to 5:1, then mix them in water, stir at room temperature until fully reacted, and then separate, purify, and dry to obtain TA@β free radical scavenger; S2: Add the free radical scavenger obtained in step S1, as well as phosphate ester monomers and acrylate monomers to the lithium salt electrolyte, stir and mix to obtain a mixed solution, inject it into the lithium-ion battery, and then encapsulate the battery. The free radical scavenger is present in a quantity of 1-100 parts by weight, and the phosphate ester monomer and the acrylate monomer are both present in a quantity of 200-600 parts by weight; the mass concentration of the free radical scavenger is 0.1-10 g / L, and the mass concentrations of the phosphate ester monomer and the acrylate monomer are 20-60 g / L and 20-60 g / L, respectively. The lithium salt is one or a mixture of two or more of lithium hexafluorophosphate, lithium dioxalatoborate, lithium tetrafluoroborate, lithium bis(difluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide; the phosphate ester monomer is one or a mixture of two or more of di[2-(methacryloyloxy)ethyl]phosphate, di[2-(acryloyloxy)ethyl]phosphate, dimethyl vinyl phosphate, diethyl vinyl phosphate, dipropyl vinyl phosphate, and 2-(methacryloyloxy)ethyl-2-(trimethylamino)ethyl phosphate; and the acrylate monomer is one or a mixture of two or more of trimethylolpropane triacrylate, cyanuric acid triacrylate, pentaerythritol tetraacrylate, and 1,6-hexanediol diacrylate. S3: Irradiate the encapsulated battery obtained in step S2 using gamma rays or an electron beam, and polymerize the mixed solution in situ inside the lithium-ion battery to obtain tannic acid TA@β nucleating agent-doped gel electrolyte TA@β- x / GPE- y , where TA@β- x Represents the quality of tannic acid@β nucleating agent, GPE- y Represents the gel electrolyte gel fraction, 0 < x <20, 0< y <60%; The irradiation absorbed dose rate is 10-150 Gy / min, and the absorbed dose is 0.1-20 kGy.

2. The method for preparing tannic acid TA@β nucleating agent-doped gel electrolyte according to claim 1, characterized in that, In step S1, the reaction time at room temperature with stirring is 1-10 days.

3. The method for preparing tannic acid TA@β nucleating agent-doped gel electrolyte according to claim 1, characterized in that, In step S1, the concentration of tannic acid is 5~50 g / L.

4. The method for preparing tannic acid TA@β nucleating agent-doped gel electrolyte according to claim 1, characterized in that, In step S2, the stirring time is 0.1-48 h.

5. The method for preparing tannic acid TA@β nucleating agent-doped gel electrolyte according to claim 1, characterized in that, In step S3, the radiation source that generates γ rays is 60 Co source or 137 Cs source; the electron beam is generated by an electron accelerator with an energy of 0.1~10 MeV.

6. A TA@β nucleating agent-doped gel electrolyte prepared by the method of any one of claims 1 to 5.

7. The application of the TA@β nucleating agent-doped gel electrolyte of claim 6 in a lithium-ion battery.

8. A lithium-ion battery, characterized in that, The lithium-ion battery uses the TA@β nucleating agent doped gel electrolyte as described in claim 6.

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