An organic polymer electrode material for flexible zinc-ion rechargeable batteries

Abstract

An organic polymer electrode material for flexible zinc-ion rechargeable batteries belongs to the field of zinc-ion batteries. An organic polymer@activated carbon cloth composite electrode is prepared using 1,5-dihydroxynaphthalene organic molecules as a precursor. The prepared electrode is assembled into an aqueous zinc-ion secondary battery. The active groups of the electrode can act as strong electron donors, accommodating repeated insertion and extraction of active ions. Its chemical bond rearrangement helps improve the battery's rate capability and cycle stability. A sandwich-structured flexible zinc-ion battery was assembled using the prepared electrode, and charge-discharge tests were conducted. The results show that the electrode can maintain its discharge capacity well when used in flexible zinc-ion batteries, and its performance is relatively stable. The raw materials for this electrode material are inexpensive and readily available, and can be used for large-scale production. This invention promotes the development of electrode materials for flexible zinc-ion secondary batteries and provides an important reference for the commercialization of flexible batteries.

Description

Technical Field

[0001] This invention belongs to the field of organic polymer aqueous battery science and technology, specifically relating to an organic polymer electrode material for flexible zinc-ion rechargeable batteries and its application. Background Technology

[0002] With the rapid changes in people's lifestyles, the demand for flexible, portable, and wearable electronic devices is also gradually increasing. Since wearable devices are mostly worn on flexible, curved parts of the body, this necessitates the development of suitable flexible power sources to complement them. Currently, flexible batteries are widely used in daily life, and their integration with electronic devices in wearable devices enables diversified application scenarios. In medical testing, they can monitor and analyze health data in real time for medical personnel; in communication and entertainment, personalized apps can be customized for learning and communication; in daily exercise, they can detect body posture and movements, providing corresponding training guidance; and in fire and rescue, they can monitor changing ambient temperatures or measure activity levels to better adapt to the environment and provide timely rescue. Therefore, to adapt to the development of next-generation flexible electronic devices, the development of high-performance flexible energy storage devices has become a research hotspot in recent years.

[0003] Flexible lithium-ion batteries have attracted much attention due to their long cycle time and high energy density. However, lithium resources are scarce, and organic electrolytes are flammable and explosive, posing a risk of thermal runaway during use. Furthermore, when combined with flexible wearable devices to form an integrated electrode, highly sealed packaging is required to prevent electrolyte leakage, which undoubtedly increases the difficulty of manufacturing processes and equipment maintenance. Therefore, the market urgently needs low-cost, highly safe micro-flexible energy storage technology to provide reliable energy storage solutions for these devices.

[0004] Among these, aqueous batteries are the most competitive candidates for the aforementioned devices due to their inherent safety. Electroactive organic materials have received considerable attention over the past two decades due to their diverse structures, excellent overall performance, wide variety, abundant raw materials, low cost, and environmental friendliness. These organic polymer materials not only possess the conductivity of metals but also the flexibility of polymers, making them easy to process. More importantly, they exhibit reversible electrochemical redox activity and high theoretical specific capacity (200-1000 mAh g⁻¹). Therefore, the development of high-performance aqueous organic flexible batteries is of great significance. Summary of the Invention

[0005] To address the above problems and shortcomings in this field, the present invention aims to provide an organic polymer electrode material for flexible zinc-ion batteries. Using the inexpensive organic small-molecule monomer 1,5-dihydroxynaphthalene, a polymer electrode material with excellent hydrophilicity and high conductivity is prepared through polymerization using a simple electrochemical device, overcoming the deficiencies of existing inorganic materials. The organic polymer@activated carbon cloth composite electrode was validated as the working electrode in an aqueous organic battery system. Results showed that it can adapt to repeated insertion / extraction of active ions, exhibiting rapid reaction kinetics and long-term cycle stability, thus paving the way for the practical application of flexible zinc-ion batteries.

[0006] In a first aspect, the present invention provides an organic polymer electrode material, namely an organic polymer@activated carbon cloth composite electrode, wherein the organic polymer is poly(1,5-dihydroxynaphthalene), and the chemical structural formula of its precursor 1,5-dihydroxynaphthalene is shown below:

[0007]

[0008] Secondly, the present invention also provides a method for preparing an organic polymer@activated carbon cloth composite electrode, characterized in that the preparation process is as follows:

[0009] (1) Preparation of activated carbon carbon cloth conductive current collector.

[0010] The untreated carbon cloth was cut into rectangles slightly smaller than the size of the platinum sheet used as the counter electrode.

[0011] Activated carbon, Ketjen black, and polyvinylidene fluoride were mixed and ground in a weight ratio of 8:1:1 to obtain a mixed powder. A certain amount of organic solvent was added to the mixed powder, and the mixture was further wet-ground to prepare a nanoporous carbon slurry with a high specific surface area. The obtained slurry was uniformly coated on a cut carbon cloth and dried in a vacuum oven at 90 ℃ for 24 h to obtain a conductive current collector activated carbon cloth.

[0012] (2) Prepare a dilute sulfuric acid solution, dissolve the organic monomer 1,5-dihydroxynaphthalene in the sulfuric acid solution, stir and then transfer it to an electrolytic cell to obtain an electrolyte;

[0013] (3) Using activated carbon cloth as the working electrode, the working electrode, counter electrode, and reference electrode are placed in an electrolytic cell containing the electrolyte from step (2) and connected to an electrochemical workstation for cyclic voltammetry scanning.

[0014] Furthermore, the organic solvent is N-methylpyrrolidone;

[0015] Step (2) Electrolyte: Dissolve 0.02 M of 1,5-dihydroxynaphthalene organic monomer in a prepared 1 M sulfuric acid solution and stir to obtain solution A. Transfer solution A into the electrolytic cell.

[0016] Step (3) involves performing cyclic voltammetry scanning using an electrochemical workstation, with the voltage range set between -0.2 and 0.9 V and the scan rate controlled at 20 mV s. -1 The number of cycles can be increased as the desired polymerization load increases, and can be controlled between 50 and 300 cycles.

[0017] After the cycle is complete, wash three times with deionized water and vacuum dry.

[0018] Thirdly, the present invention also provides the application of organic polymer electrode materials as working electrodes in zinc-ion batteries. Furthermore, a three-electrode system is employed, comprising a working electrode, a counter electrode, a reference electrode, and an electrolyte, wherein the organic polymer electrode material (i.e., the working electrode) is the aforementioned organic polymer@activated carbon cloth composite electrode.

[0019] According to the aqueous zinc-ion battery provided by the present invention, the counter electrode material is a platinum sheet; the reference electrode is an Ag / AgCl electrode filled with a saturated KCl solution; and the electrolyte is an aqueous zinc-ion electrolyte.

[0020] According to an embodiment of the present invention, the aqueous zinc ion electrolyte may be 1-5 M. Aqueous solution of Zn(OTF)2.

[0021] Furthermore, a semi-solid flexible zinc-ion rechargeable battery is provided, characterized in that it is a sandwich-structured flexible zinc-ion battery, comprising a zinc foil anode layer and an organic polymer electrode material cathode layer of the present invention, with a gel electrolyte layer between the anode layer and the cathode layer.

[0022] The gel electrolyte layer is a polyacrylamide gel electrolyte, which is obtained by dissolving acrylamide, ammonium persulfate, and N,N-methylenebisacrylamide in deionized water, stirring until uniform, heating the resulting solution in a water bath at 60°C until completely solidified, and then immersing it in Zn(OTF)2 electrolyte (e.g., concentration of 0.5-5 M) for 24 hours.

[0023] Through research, this invention has found that using the above-mentioned organic polymer@activated carbon cloth composite electrode, with poly(1,5-dihydroxynaphthalene) as the positive electrode material for aqueous zinc-ion batteries, can effectively improve the cycle stability and rate performance of the battery.

[0024] This invention provides an organic polymer@activated carbon cloth composite electrode and its preparation method, and applies it to an aqueous zinc-ion battery, where the battery exhibits excellent performance. The electrode was assembled into a flexible battery, and its electrochemical performance was tested, demonstrating its normal operation. This organic polymer@activated carbon cloth composite electrode not only has significant scientific research value but also provides important reference for the commercialization of flexible batteries. Attached Figure Description

[0025] Figure 1 Schematic diagram of an electropolymerization device

[0026] Figure 2 The cyclic voltammetry curve of 0.02 M 1,5-dihydroxynaphthalene in 1 M H2SO4 in Example 1 is shown, with a scan frequency of 20 mV / s. -1 ;

[0027] Figure 3 This is a scanning electron microscope image of poly(1,5-dihydroxynaphthalene)@activated carbon cloth in Example 1;

[0028] Figure 4 The infrared spectrum of poly(1,5-dihydroxynaphthalene)@activated carbon cloth in Example 1;

[0029] Figure 5 The image shows the Raman spectrum of poly(1,5-dihydroxynaphthalene)@activated carbon cloth in Example 1.

[0030] Figure 6 The X-ray photoelectron spectrum of poly(1,5-dihydroxynaphthalene)@activated carbon cloth in Example 1 is shown.

[0031] Figure 7 The contact angle test diagram of poly(1,5-dihydroxynaphthalene)@activated carbon cloth in Example 1 is shown.

[0032] Figure 8 , Figure 9 The cyclic voltammetry curves and charge-discharge curves of the zinc-ion aqueous battery assembled with poly(1,5-dihydroxynaphthalene)@activated carbon cloth as the working electrode in Example 1 are shown.

[0033] Figure 10 This is a photograph of the gel electrolyte prepared in Example 2;

[0034] Figure 11 This is a photograph of the flexible zinc-ion battery with a sandwich structure assembled in Example 2.

[0035] Figure 12 The charge-discharge curves of the flexible zinc-ion battery with the sandwich structure in Test Example 1 are shown. Detailed Implementation

[0036] The following preferred embodiments are used to further describe the present invention, but are not intended to limit the scope of the invention.

[0037] Unless otherwise specified, all reagents and instruments used in the following examples are commercially available.

[0038] Example 1

[0039] This embodiment provides a poly(1,5-dihydroxynaphthalene)@activated carbon cloth composite electrode, and the preparation method is as follows:

[0040] The carbon cloth was cut into rectangles slightly smaller than the size of the platinum counter electrode (3 cm x 3 cm). 120 mg of activated carbon, 15 mg of Ketjen black, and 15 mg of polyvinylidene fluoride were mixed and ground evenly, then dissolved in 1.5 ml of N-methylpyrrolidone. The mixture was stirred thoroughly to form a black slurry. The slurry was evenly coated onto the front side of the cut carbon cloth. The coated carbon cloth was placed face up in a vacuum drying oven and dried at 90 °C for 24 h. To quantify the active material, the carbon cloth was weighed before and after coating. 327 mg of 1,5-dihydroxynaphthalene was added to 100 ml of 1 M H₂SO₄ and stirred to form a homogeneous solution. The solution was transferred to a 200 ml electrolytic cell. The dried activated carbon cloth was used as the working electrode and placed in the electrolytic cell along with the platinum counter electrode and the Ag / AgCl reference electrode. A schematic diagram of the apparatus is shown below. Figure 1 As shown, cyclic voltammetry scans were performed using an electrochemical workstation with a voltage range of -0.2 to 0.9 V and a scan rate of 20 mV / s. -1 The number of cycles is 100; the cyclic voltammetry curve of its electropolymerization process is as follows: Figure 2 As shown, the scanning electron microscope image of the obtained poly(1,5-dihydroxynaphthalene)@activated carbon cloth composite electrode is as follows. Figure 3 As shown, the infrared spectrum, Raman spectrum, and X-ray photoelectron spectrum are respectively as follows: Figure 4 , 5 As shown in Figure 6. The electrolyte-electrode interface contact angle test is as follows: Figure 7 As shown.

[0041] The poly(1,5-dihydroxynaphthalene)@activated carbon cloth composite electrode obtained above was used as the electrode material for a zinc-ion battery to assemble a three-electrode battery and tested. Specifically, 10 mL of deionized water was poured into a beaker, and 3.64 g of zinc trifluoromethanesulfonate (Zn(OTF)2) was added. The mixture was magnetically stirred to prepare a 1 M solution as the electrolyte for the aqueous zinc battery. The obtained electrode was used as the working electrode and cut to a size of 0.5*0.5 cm. The areal loading was calculated based on the mass of the carbon cloth before and after electropolymerization. Using a Swagelok battery mold, a three-electrode battery was assembled with a platinum sheet as the counter electrode and an Ag / AgCl reference electrode to test its electrochemical performance. Its cyclic voltammetry and charge-discharge curves in Zn(OTF)2 are shown below. Figure 8 and Figure 9 As shown, the test voltage range is -0.3 to 0.9 V, and the scan rate is 1.0 mV / s. -1 The current density is 0.1 A g. -1 . Figure 9The charge-discharge curves show that at 0.1 Ag -1 At current densities, the specific capacity can reach up to 224 mAh g. -1 Furthermore, after 50 cycles, the specific capacity did not show a significant decrease.

[0042] Example 2

[0043] This embodiment provides a flexible zinc-ion battery with a sandwich structure, which consists of the following structure: a zinc foil anode layer, a gel electrolyte layer, a cathode layer using the above-obtained poly(1,5-dihydroxynaphthalene)@activated carbon cloth composite electrode, and a polyethylene insulating encapsulation layer.

[0044] This embodiment provides a method for fabricating a wearable flexible zinc-ion battery with a sandwich structure, including the following steps:

[0045] 1. Select a 20μm thick zinc foil as the anode, and use a paper cutter to cut the zinc foil into 5cm×5cm squares to obtain the zinc foil anode layer;

[0046] 2. Preparation of polyacrylamide gel electrolyte: Acrylamide, ammonium persulfate, and N,N-methylenebisacrylamide were dissolved in deionized water and stirred until homogeneous. The resulting solution was heated in a water bath at 60°C until completely solidified, and then immersed in 1 M Zn(OTF)₂ electrolyte for 24 hours to obtain the gel electrolyte as shown. Figure 10 As shown.

[0047] 3. Using the poly(1,5-dihydroxynaphthalene)@activated carbon cloth composite electrode obtained above as the cathode layer, cut it into 5cm×5cm squares using a paper cutter.

[0048] 4. Align the cut zinc foil anode layer, gel electrolyte layer, and cathode layer in a top-to-bottom order, and seal them using a vacuum sealing machine in a soft-pack manner to obtain the desired result. Figure 11 A schematic diagram of a flexible zinc-ion battery with a sandwich structure is shown.

[0049] Test Example 1: Performance Testing of Flexible Zinc-Ion Batteries with Sandwich Structure

[0050] The performance of the flexible zinc-ion battery with the sandwich structure in Example 2 was tested, and the test results are as follows: Voltage-specific capacity curve as shown. Figure 12 As shown. From Figure 12 As can be seen, the flexible battery with a sandwich structure can maintain its discharge capacity well, at 0.1 A g. -1 At a current density of [value missing], the discharge specific capacity can reach 185 mAh g. -1 And its performance is relatively stable after 20 cycles.

[0051] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An organic polymer electrode material, characterized in that, It is an organic polymer@activated carbon cloth composite electrode, wherein the organic polymer is poly(1,5-dihydroxynaphthalene).

2. The method for preparing an organic polymer electrode material according to claim 1, characterized in that, The preparation process includes the following: (1) Preparation of activated carbon carbon cloth conductive current collector Activated carbon, Ketjen black, and polyvinylidene fluoride were mixed and ground in a weight ratio of 8:1:1 to obtain a mixed powder. A certain amount of organic solvent was added to the mixed powder, and the mixture was further wet-ground to prepare a nanoporous carbon slurry with a high specific surface area. The obtained slurry was uniformly coated on a cut carbon cloth and dried to obtain a conductive current collector activated carbon cloth. (2) Prepare a dilute sulfuric acid solution, dissolve the organic monomer 1,5-dihydroxynaphthalene in the sulfuric acid solution, stir and then transfer it to an electrolytic cell to obtain an electrolyte; (3) Using activated carbon cloth as the working electrode, the working electrode, counter electrode, and reference electrode are placed in an electrolytic cell containing the electrolyte from step (2) and connected to an electrochemical workstation for cyclic voltammetry scanning.

3. The method according to claim 2, characterized in that, The organic solvent is N-methylpyrrolidone.

4. The method according to claim 2, characterized in that, Step (2) Electrolyte: Dissolve 0.02 M of 1,5-dihydroxynaphthalene organic monomer in a prepared 1 M sulfuric acid solution and stir to obtain solution A. Transfer solution A into the electrolytic cell.

5. The method according to claim 2, characterized in that, Step (3) involves performing cyclic voltammetry scanning using an electrochemical workstation, with the voltage range set between -0.2 and 0.9 V and the scan rate controlled at 20 mV s. -1 The number of cycles increases with the increase of the desired polymerization load, and is controlled between 50 and 300 cycles.

6. The method according to claim 2, characterized in that, After the cycle is complete, wash three times with deionized water and vacuum dry.

7. The application of the organic polymer electrode material according to claim 1, wherein the organic polymer electrode material is used as the working electrode of a zinc-ion battery.

8. The application according to claim 7 employs a three-electrode system comprising a working electrode, a counter electrode, a reference electrode, and an electrolyte, wherein the organic polymer electrode material (i.e., the working electrode) is the aforementioned organic polymer@activated carbon cloth composite electrode.

9. The application according to claim 8, wherein the counter electrode material is a platinum sheet; the reference electrode is an Ag / AgCl electrode filled with saturated KCl solution; and the electrolyte is an aqueous zinc ion electrolyte. The aqueous zinc ion electrolyte is a 1-5 MZn(OTF)2 aqueous solution.

10. A semi-solid flexible zinc-ion rechargeable battery, characterized in that, A flexible zinc-ion battery with a sandwich structure includes a zinc foil anode layer and an organic polymer electrode material cathode layer as described in claim 1, with a gel electrolyte layer between the anode layer and the cathode layer. The gel electrolyte layer is a polyacrylamide gel electrolyte, which is obtained by dissolving acrylamide, ammonium persulfate, and NN methylenebisacrylamide in deionized water, stirring until uniform, heating the resulting solution in a water bath at 60°C until completely solidified, and then immersing it in Zn(OTF)2 electrolyte for 24 hours.