A method of using an argon plasma to improve the electrochemical performance of an electrolyte

Abstract

The application discloses a method for improving the electrochemical performance of an electrolyte by using argon plasma, which comprises the following steps: (1) mixing and stirring a silk fibroin solution, a sodium dodecyl sulfate (SDS) solution and a poly(3,4-ethylenedioxythiophene): polystyrene sulfonic acid (PEDOT:PSS) solution to obtain a mixed solution, and placing the mixed solution in a container; and (2) injecting a low-temperature argon plasma jet into the container to perform normal-temperature and normal-pressure treatment, so as to obtain a hydrogel electrolyte precursor solution after plasma treatment, and standing to obtain a hydrogel electrolyte. The method can improve the electrochemical performance of the electrolyte by using argon plasma, and can improve the electrochemical performance of the electrolyte without affecting the mechanical strength of the electrolyte.

Description

Technical Field

[0001] This invention relates to the field of improving the electrochemical performance of electrolytes, specifically a method for using argon plasma to improve the electrochemical performance of electrolytes. Background Technology

[0002] Electrolytes significantly influence the electrochemical parameters of batteries, such as energy density and capacitance. Common methods to improve the electrochemical performance of electrolytes include changing the amount of conductive dopant. However, this inevitably comes at the cost of reduced mechanical properties of the hydrogel electrolyte. For example, in the publication "Polyacrylamide / Chitosan-Based Conductive Double Network Hydrogels with Outstanding Electrical and Mechanical Performance at Low Temperatures," the antifreeze conductive chitosan hydrogel shows that increasing the polyaniline content can improve the conductivity of the hydrogel, but decreases the Young's modulus (ACS Applied Materials & Interfaces 2021, 13, 34942-34953); in "The Manufacture of Unbreakable Bionics via Multifunctional and Self-Healing Silk–Graphene Hydrogels," the ultra-viscous silk-graphene hydrogel shows that increasing the graphene content can enhance conductivity, but decreases self-healing properties and viscosity (Advanced Materials 2021, 33, 2100047); and in "Deep Learning Assisted Body Area Triboelectric Hydrogel Sensor,"... In Network for Infant Care, increasing the NaCl content in the agarose gel increased the output voltage of the biosensor monitoring infant movement, but decreased the hydrogel strength (Advanced Functional Materials 2022, 32, 2204803). This loss of mechanical properties in the hydrogel electrolyte subsequently affects battery life and efficiency.

[0003] Plasma applications in the hydrogel field include the preparation of bactericidal gels using plasma. For example, Chinese patent CN109890121A describes a plasma gel prepared from physiological saline treated with plasma, which can efficiently inactivate various bacteria and fungi in a short time (publication date: June 14, 2019). This invention uses argon plasma jets to enhance the electrochemical performance of the hydrogel electrolyte without affecting its mechanical properties. Summary of the Invention

[0004] To overcome the shortcomings of existing methods that improve the electrochemical performance of hydrogel electrolytes by changing the amount of conductive doping, which often results in a loss of mechanical properties, this invention provides a method for improving the electrochemical performance of electrolytes using argon plasma. This invention employs argon plasma to improve the electrochemical performance of electrolytes, a method that not only enhances electrochemical performance but also does not affect the mechanical strength of the electrolyte.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A method for using argon plasma to improve the electrochemical performance of electrolytes includes the following steps:

[0007] (1) Mix the silk fibroin solution, sodium dodecyl sulfate (SDS) solution and poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) solution evenly to obtain a mixed solution, and place the mixed solution in a container;

[0008] (2) A low-temperature argon plasma jet is injected into the container and treated at room temperature and pressure to obtain a plasma-treated hydrogel electrolyte precursor solution. After standing, the hydrogel electrolyte is obtained.

[0009] Further, in step (1), 6 mL of a 4.00 wt% silk fibroin solution, 600 μL of a 5.00 wt% sodium dodecyl sulfate (SDS) solution, and 575 μL of a 1.05 wt% poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) solution are stirred evenly, and the mixed solution is placed in a beaker.

[0010] Furthermore, in step (2), the processing time is 3 minutes and the settling time is 15 minutes.

[0011] Further, in step (2), the device for generating the low-temperature argon plasma jet is a dual-electrode low-temperature plasma jet device. The low-temperature plasma jet device includes a plasma generator, a copper tube, a glass tube a, a thin glass tube b, an argon gas cylinder gas source device, a rotor flow meter, a square copper sheet, a hydrogel electrolyte, and a container. The plasma generator is equipped with a high-voltage output terminal, a voltage regulator, an output frequency adjustment knob, a low-voltage output terminal, and a ground wire. The high-voltage output terminal of the plasma generator is connected to the copper tube. The copper tube is covered with a glass tube a. The lower end of the glass tube a is connected to the thin glass tube b. The argon gas cylinder gas source device is connected to the rotor flow meter and the copper tube in sequence. The voltage regulator is connected to the plasma generator. The low-voltage output terminal of the plasma generator is connected to the square copper sheet. The hydrogel electrolyte is placed in the container. The container is placed on the square copper sheet. The container is placed below the opening of the thin glass tube b. The ground wire of the plasma generator is grounded.

[0012] Further, in step (2), the high-voltage output terminal of the plasma generator and the copper tube are connected by copper clips. The copper tube serves as the positive electrode, and the outlet of the glass tube a is a thin glass tube b. An argon gas cylinder gas source device is connected above the copper tube. The gas flow rate is controlled by a rotor flow meter and the flow rate is set to 2L / min. The voltage regulator and output frequency adjustment knob of the plasma generator are adjusted to pass 20kV high voltage to the copper tube to ionize the argon gas and generate a low-temperature argon plasma jet at the outlet of the copper tube. The negative electrode of the dual-electrode structure low-temperature plasma jet device is a square copper sheet, which is placed below the copper tube and connected to the low-voltage output terminal of the plasma generator by copper clips. The argon plasma discharge time is set to 3 minutes. The generated low-temperature argon plasma jet is injected into a container containing hydrogel electrolyte.

[0013] Furthermore, in step (2), the inner diameter of the copper tube is 3mm; the inner diameter of the glass tube a is 4mm and the thickness is 2mm; the inner diameter of the thin glass tube b is 3mm and the height is 10mm.

[0014] Furthermore, in step (2), the side length of the square copper sheet is 65mm.

[0015] Specifically, a method for using argon plasma to improve the electrochemical performance of electrolytes employs a dual-electrode low-temperature plasma jet device. A copper tube with an inner diameter of 3mm is connected to the high-voltage output terminal of a CTP-2000K plasma generator via a copper clamp as the positive electrode. For safety, a glass tube a, with an inner diameter of 4mm and a thickness of 2mm, is fitted over the copper tube. The outlet of glass tube a is a short, thin glass tube b, with an inner diameter of 3mm and a height of 10mm. An argon gas cylinder is connected above the copper tube, and the gas flow rate is controlled using a rotor flow meter, set to 2L / min. Adjusting the voltage regulator and output frequency control knob of the plasma generator allows 20kV high voltage to be applied to the copper tube to ionize the argon gas, generating a low-temperature argon plasma jet at the outlet of the copper tube. The negative electrode is a square copper sheet with a side length of 65mm, placed below the copper tube and connected to the low-voltage output terminal of the plasma generator via a copper clamp. The plasma generator requires a grounding wire. The argon plasma discharge time is set to 3 minutes. The generated low-temperature argon plasma jet is injected into a beaker containing hydrogel electrolyte, which causes the hydrogel electrolyte to contain a large number of ions, reducing its impedance. At the same time, the electrolyte also acquires many active substances, which improves its capacitance performance.

[0016] In this invention, the low-temperature argon plasma jet has a temperature range of 100K to 1000K and an argon plasma temperature range of 303K to 313K.

[0017] The beneficial effect of this invention is that argon plasma improves the electrochemical performance (including capacitance and resistance) of hydrogel electrolytes without affecting the mechanical properties of the electrolytes.

[0018] By injecting argon plasma into the hydrogel electrolyte, the hydrogel electrolyte contains a large number of ions, resulting in a more than 50% reduction in impedance in the low-frequency range (0.01–1 Hz). Furthermore, the contained active materials reduce the capacitance of the hydrogel electrolyte from the original 1.597 × 10⁻⁶ Ω·cm. -5 F increased to 2.7418*10 -5 F, and argon plasma does not affect the mechanical properties of hydrogel electrolytes. Attached Figure Description

[0019] Figure 1 This is a diagram of the process apparatus for improving the electrochemical performance of electrolytes using argon plasma, as described in this invention.

[0020] In the diagram, 1. Plasma generator, 2. High-voltage output terminal, 3. Copper tube, 4. Glass tube a, 5. Thin glass tube b, 6. Argon gas cylinder gas source device, 7. Rotor flow meter, 8. Pressure regulator, 9. Output frequency adjustment knob, 10. Argon plasma jet, 11. Square copper sheet, 12. Low-voltage output terminal, 13. Ground wire, 14. Hydrogel electrolyte, 15. Beaker.

[0021] Figure 2 The AC impedance spectra of the hydrogel electrolyte before and after argon plasma treatment are shown. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. However, the following embodiments are only for explaining the present invention, and the scope of protection of the present invention should include all the contents of the claims. Moreover, through the description of the following embodiments, those skilled in the art can fully implement all the contents of the claims of the present invention.

[0023] Figure 1 This is a diagram of a process apparatus for using argon plasma to improve the electrochemical performance of electrolytes. Figure 1 As shown, this invention uses a dual-electrode structure low-temperature plasma jet device, which includes a CTP-2000K plasma generator 1, a copper tube 3, a glass tube a4, a thin glass tube b5, an argon gas cylinder supply device 6, a rotor flowmeter 7, a square copper sheet 11, a hydrogel electrolyte 14, and a beaker 15. The plasma generator is a CTP-2000K plasma generator. The plasma generator 1 is equipped with a high-voltage output terminal 2, a voltage regulator 8, an output frequency adjustment knob 9, a low-voltage output terminal 12, and a ground wire 13. The high-voltage output terminal 2 of the plasma generator 1 is connected to the copper tube 3. The glass tube a4 is wrapped around the copper tube. The lower end of the glass tube a4 is connected to the thin glass tube b5. The lower end of the glass tube a4 is connected to the thin glass tube b5. The argon gas cylinder supply device 6 is connected to the rotor flowmeter 7 and the copper tube 3 in sequence. The voltage regulator 8 is connected to the plasma generator 1. The low-voltage output terminal 12 of plasma generator 1 is connected to the square copper plate 11. The hydrogel electrolyte 14 is placed inside beaker 15. Beaker 15 is placed on the square copper plate 11. Beaker 15 is positioned below the opening of the thin glass tube b5. The ground wire 13 of plasma generator 1 is grounded.

[0024] In use, the dual-electrode structure cryogenic plasma jet device uses a copper tube 3 connected to the high-voltage output terminal 2 of the CTP-2000K plasma generator 1 via a copper clamp as the positive electrode. The inner diameter of the copper tube is 3mm. For safety, a glass tube a4 is fitted over the copper tube, with an inner diameter of 4mm and a thickness of 2mm. A short, thin glass tube b5 exits from glass tube a4. The thin glass tube b5 has an inner diameter of 3mm and a height of 10mm. An argon gas cylinder gas source device 6 is connected above the copper tube 3; air and helium gas source devices can also be used. The gas flow rate is controlled by adjusting the knob of the rotor flowmeter 7, set to 2L / min. Other flow rates can be used, but the voltage of the ionizing gas needs to be adjusted accordingly. By adjusting the voltage regulator 8 and the output frequency adjustment knob 9 of the plasma generator 1, a 20kV high-voltage current is applied to the copper tube to ionize the argon gas, generating a cryogenic argon plasma jet 10 at the outlet of the copper tube. The negative electrode of the device is a square copper sheet 11 with a side length of 65 mm, placed below the copper tube, and connected to the low-voltage output terminal 12 of the plasma generator with a copper clip. The plasma generator needs to be grounded 13. The argon plasma discharge time is set to 3 minutes, and the discharge time can be changed as needed. The generated low-temperature argon plasma jet is injected into a beaker 15 containing a hydrogel electrolyte (6 mL of 4.00% silk fibroin solution + 600 μL of 5.00% sodium dodecyl sulfate (SDS) solution + 575 μL of 1.05% poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) solution, where silk fibroin is the gel base material, SDS is the gel accelerator, and PEDOT:PSS is the doped conductive material) 14, so that the argon plasma improves the electrochemical performance of the electrolyte.

[0025] This invention does not have any particular limitation on the source of silk fibroin and poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS), and commercially available products well known in the art are acceptable.

[0026] Example:

[0027] Using the aforementioned dual-electrode low-temperature plasma jet apparatus, argon was used as the discharge gas at a flow rate of 2 L / min and a discharge voltage of 20 kV. 6 mL of a 4.00 wt% silk fibroin solution, 600 μL of a 5.00 wt% sodium dodecyl sulfate (SDS) solution, and 575 μL of a 1.05 wt% poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) solution were stirred until homogeneous, and the mixture was placed in a beaker. Low-temperature argon plasma was injected into the mixture at room temperature and pressure for 3 min. The plasma-treated hydrogel electrolyte precursor solution was obtained. After standing for 15 min, the hydrogel electrolyte (denoted as Ar180s) was obtained.

[0028] (1) Impedance testing of hydrogel electrolyte after argon plasma treatment

[0029] For hydrogel electrolytes in the frequency range of 0.01–10 5 AC impedance testing was performed at a scan rate of 0.1 V / s and a Hz refresh rate. For example... Figure 2 As shown, the hydrogel electrolyte (Ar180s) treated with argon plasma for 3 min exhibits a significantly reduced impedance of over 50% in the low-frequency (0.01–1 Hz) range compared to the hydrogel without argon plasma treatment (referred to as the blank sample).

[0030] The preparation method of the hydrogel without argon plasma treatment (denoted as the blank sample) is as follows: 6 mL of a 4.00 wt% silk fibroin solution, 600 μL of a 5.00 wt% sodium dodecyl sulfate (SDS) solution, and 575 μL of a 1.05 wt% poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) solution were stirred until homogeneous. The mixture was then placed in a beaker and allowed to stand for 15 min to obtain the hydrogel without argon plasma treatment.

[0031] (2) Capacitance test of hydrogel electrolyte after argon plasma treatment

[0032] The capacitance of the hydrogel electrolyte after argon plasma treatment was measured using cyclic voltammetry. The capacitance was calculated using the following formula: C = (∫idV) / 2vV, where ∫idV is the area enclosed by the cyclic voltammetry curve, v is the voltage scan rate (set to 0.1V / s), and V is the scan voltage range (set to -0.5V to 0.5V). The calculated capacitance of the hydrogel without argon plasma treatment was 1.5969 * 10⁻⁶. -5 F, while the hydrogel electrolyte capacitance increased to 2.7418*10 after argon plasma treatment for 3 minutes. -5 F.

[0033] (3) Compressive strength test of hydrogel electrolyte after argon plasma treatment

[0034] Cylindrical hydrogel samples with a diameter of 1.0 cm and a height of 1.5 cm were cut out. Compression tests were performed on the hydrogel samples at a speed of 1 cm / min. Each sample was tested three times, and the average value was calculated. The results showed that the compressive strength of the hydrogel electrolyte was 0.15 MPa before and after argon plasma treatment, indicating that argon plasma did not affect the mechanical strength of the hydrogel electrolyte.

[0035] The parts of this invention not described in detail are well-known to those skilled in the art. The embodiments described above are merely preferred embodiments of the invention, and do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Various modifications and improvements to the technical solutions of this invention made by those skilled in the art without departing from the spirit of the invention should fall within the protection scope defined by the claims of this invention.

Claims

1. A method for using argon plasma to improve the electrochemical performance of electrolytes, characterized in that, Includes the following steps: (1) Mix the silk fibroin solution, sodium dodecyl sulfate (SDS) solution and poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) solution evenly to obtain a mixed solution, and place the mixed solution in a container; (2) Inject a low-temperature argon plasma jet into the container, treat it at room temperature and pressure to obtain a plasma-treated hydrogel electrolyte precursor solution, let it stand, and obtain a hydrogel electrolyte; In step (2), the device for generating the low-temperature argon plasma jet is a dual-electrode structure low-temperature plasma jet device, which includes a plasma generator (1), a copper tube (3), a glass tube a (4), a thin glass tube b (5), an argon gas cylinder gas source device (6), a rotor flow meter (7), a square copper sheet (11), a hydrogel electrolyte (14), and a container; The plasma generator (1) is equipped with a high-voltage output terminal (2), a voltage regulator (8), an output frequency adjustment knob (9), and a low-voltage output terminal (2). High-voltage output terminal (12) and ground wire (13); high-voltage output terminal (2) of plasma generator (1) is connected to copper tube (3); glass tube a (4) is wrapped around the outer layer of copper tube; the lower end of glass tube a (4) is connected to thin glass tube b (5); argon gas cylinder gas source device (6) is connected to rotor flow meter (7) and copper tube (3) in sequence; voltage regulator (8) is connected to plasma generator (1); low-voltage output terminal (12) of plasma generator (1) is connected to square copper plate (11); hydrogel electrolyte (14) is placed in container; container is placed on square copper plate (11); container is placed below the opening of thin glass tube b (5); ground wire (13) of plasma generator (1) is grounded.

2. The method according to claim 1, characterized in that: In step (1), 6 mL of 4.00 wt% silk fibroin solution, 600 μL of 5.00 wt% sodium dodecyl sulfate (SDS) solution and 575 μL of 1.05 wt% poly(3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) solution are stirred evenly and the mixed solution is placed in a beaker.

3. The method according to claim 1, characterized in that: In step (2), the processing time is 3 minutes and the settling time is 15 minutes.

4. The method according to claim 1, characterized in that: In step (2), the high voltage output terminal of the plasma generator and the copper tube (3) are connected by copper clips. The copper tube (3) serves as the positive electrode glass tube a (4) and the outlet is a thin glass tube b (5). An argon gas cylinder gas source device is connected above the copper tube. The gas flow rate is controlled by a rotor flow meter (7) and the flow rate is set to 2 L / min. Adjust the voltage regulator (8) and output frequency adjustment knob (9) of the plasma generator to pass 20 kV high voltage to ionize argon gas through the copper tube, and generate a low-temperature argon plasma jet at the outlet of the copper tube; the negative electrode of the dual-electrode structure low-temperature plasma jet device is a square copper sheet (11), which is placed below the copper tube (3) and connected to the low-voltage output terminal (12) of the plasma generator with a copper clip; the argon plasma discharge time is set to 3 minutes; the generated low-temperature argon plasma jet is injected into a container containing the mixed solution.

5. The method according to claim 1, characterized in that: In step (2), the inner diameter of the copper tube (3) is 3 mm; the inner diameter of the glass tube a (4) is 4 mm and the thickness is 2 mm; the inner diameter of the thin glass tube b (5) is 3 mm and the height is 10 mm.

6. The method according to claim 1, characterized in that: In step (2), the side length of the square copper sheet (11) is 65mm.

7. The method according to claim 1, characterized in that: In step (2), the dual-electrode structure low-temperature plasma jet device is used, with argon as the discharge gas, an argon flow rate of 2L / min, and a plasma generator discharge voltage of 20kV.

Images