A highly flexible, low-temperature resistant zinc-ion hybrid capacitor, its preparation method, and its application in energy storage.

Abstract

This invention discloses a highly flexible, low-temperature resistant zinc-ion hybrid capacitor, its preparation method, and its application in energy storage. 2-Acrylamide-2-methylpropanesulfonic acid, acrylic acid, zinc chloride, and ferric chloride are dissolved in deionized water, neutralized with zinc oxide, and filtered to obtain a clear solution. 2-Ketoglutaric acid is added to the resulting liquid as an initiator, and the liquid is dropped into a tetrafluoroethylene mold. Polymerization is carried out under ultraviolet irradiation to obtain a hydrogel electrolyte. Activated carbon and carbon black are dispersed in ethanol, dropped onto carbon cloth, and dried to obtain the cathode material. Zinc foil, after polishing to remove the oxide layer, is directly cut to a suitable size as the anode material. The obtained anode and cathode materials are assembled with the obtained electrolyte material into a sandwich structure to prepare the zinc-ion hybrid capacitor. The zinc-ion hybrid capacitor prepared by this invention has a high specific capacitance, maintains its capacitance under torsional bending conditions, and can operate normally at low temperatures, exhibiting excellent flexibility and low-temperature resistance.

Description

Technical Field

[0001] This invention belongs to the field of capacitor manufacturing, and more specifically, relates to the preparation method of zinc ion hybrid capacitor electrode material and hydrogel electrolyte material, and the assembly of energy storage device. Background Technology

[0002] Zinc-ion hybrid capacitors are a novel energy storage device developed in recent years, combining the characteristics of both zinc-ion batteries and supercapacitors. They possess the excellent properties of high charge / discharge rates of capacitors and high energy density of batteries. With the rapid development of wearable and portable electronic devices in recent years, there is a greater demand for functional energy storage devices (such as high flexibility, safety, and low-temperature resistance). Highly flexible energy storage devices can better meet the needs of wearable devices, while low-temperature resistance ensures that the devices can operate normally in harsh environments. Furthermore, zinc-ion hybrid capacitors using aqueous electrolytes can also effectively meet safety and environmental protection requirements. Therefore, the fabrication of highly flexible, low-temperature resistant zinc-ion hybrid capacitors has become an important research topic. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a highly flexible, low-temperature resistant zinc-ion hybrid capacitor, its preparation method, and its application in energy storage, achieving high flexibility and low-temperature resistance in the zinc-ion hybrid capacitor. The capacitance of the zinc-ion hybrid capacitor reaches 458.7 F g. -1 It also exhibits excellent flexibility, maintaining its capacity essentially unchanged under bending and torsion conditions. It operates normally at low temperatures, retaining 78.9% and 55.5% of its initial capacity at 0℃ and -18℃, respectively.

[0004] The technical objective of this invention is achieved through the following technical solution.

[0005] A highly flexible, low-temperature resistant zinc-ion hybrid capacitor has an overall sandwich structure and uses a hydrogel electrolyte. The hydrogel electrolyte is a copolymer hydrogel of monomers 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid, with a molar ratio of acrylic acid to 2-acrylamide-2-methylpropanesulfonic acid of (1:1) to (1:4). Zinc chloride, ferric chloride, and zinc oxide are added to the copolymer hydrogel. The molar ratio of zinc chloride (molar amount) to the two monomers (i.e., the sum of the molar amounts of monomers 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid) is (0.2-1):1, the molar ratio of ferric chloride to the two monomers is (5-8):100, and the molar ratio of zinc oxide to the two monomers is (0.8-1):2.

[0006] The molar ratio of acrylic acid to 2-acrylamide-2-methylpropanesulfonic acid is (1:1) to (1:3).

[0007] The molar ratio of zinc chloride to the two monomers is (0.5-1):1.

[0008] The molar ratio of ferric chloride to the two monomers is (6-8):100.

[0009] The molar ratio of zinc oxide to the two monomers is 1:2.

[0010] The anode is zinc foil; the cathode is carbon cloth uniformly coated with activated carbon and carbon black, with a mass ratio of activated carbon to carbon black of (6-8):1.

[0011] The zinc-ion hybrid capacitor of the present invention is used in energy storage, in 1A g -1 The specific capacitance at current density is 458.75 F g. -1 In 2A g -1 The specific capacitance at current density is 308.49 F g. -1 In 3A g -1 The specific capacitance at the current density is 234.37 F g. -1 , in 5A g -1 The specific capacitance at the current density is 180.62 F g. -1 , in 10A g -1 The specific capacitance at the current density is 145.62 F g. -1 It exhibits the same charge-discharge curves under torsion, bending at 90 degrees, and bending at 180 degrees, demonstrating excellent flexibility. It can operate normally at low temperatures, retaining 78.9% and 55.5% of its initial capacity at 0℃ and -18℃, respectively.

[0012] The above-mentioned capacitor is manufactured according to the following steps:

[0013] Step 1: 2-Acrylamide-2-methylpropanesulfonic acid, acrylic acid, zinc chloride, ferric chloride, and zinc oxide are uniformly dispersed in deionized water, filtered to obtain a clear solution, and an initiator is added to initiate polymerization to obtain a hydrogel electrolyte.

[0014] Step 2: Activated carbon and carbon black are ultrasonically dispersed in ethanol, then uniformly coated onto carbon cloth, and dried to obtain the cathode material; the zinc foil surface is polished to remove the oxide layer and used as the anode material.

[0015] Step 3: Assemble the anode material, hydrogel electrolyte, and cathode material into a sandwich structure to prepare a zinc ion hybrid capacitor.

[0016] In step 1, 2-acrylamide-2-methylpropanesulfonic acid, acrylic acid, and zinc oxide are reacted to disperse zinc oxide in the reaction system. Consider adding an appropriate amount of zinc oxide to neutralize the reaction system, and filter to obtain a clear solution.

[0017] In step 1, 2-ketoglutaric acid was selected as the initiator, and the hydrogel electrolyte was obtained by polymerization under ultraviolet irradiation.

[0018] In step 1, the clarified solution is dropped into a tetrafluoroethylene mold for polymerization, and the ultraviolet irradiation time is 0.5 h.

[0019] In step 2, the mass ratio of activated carbon to carbon black is (6-8):1, the ultrasonic treatment time is 30-40 min, and the carbon is dried in an oven at 50-60℃ for 30-40 min.

[0020] Compared with existing technologies, the technical solution of this invention uses acidic monomers to provide a uniformly dispersed atmosphere for the added zinc chloride, ferric chloride, and zinc oxide. The prepared zinc ion hydrogel electrolyte exhibits a solid macroscopic appearance and good flexibility, making it a suitable electrolyte material for use in zinc ion hybrid capacitors. This invention achieves the preparation and application of highly flexible, low-temperature resistant zinc ion hybrid capacitors. The method is simple, safe, and environmentally friendly. The zinc ion hybrid capacitor prepared by this invention exhibits excellent electrochemical performance, with a 1A g... -1 The specific capacitance at current density is 458.75 F g. -1 The zinc-ion hybrid capacitor prepared by this invention exhibits excellent flexibility, maintaining its capacitance unchanged under torsion, 90-degree bending, and 180-degree bending conditions. The prepared zinc-ion hybrid capacitor also demonstrates good low-temperature resistance, retaining 78.9% and 55.5% of its initial capacitance at 0℃ and -18℃, respectively. The device prepared by this invention has significant application prospects and enormous research potential. Attached Figure Description

[0021] Figure 1 This is a SEM image of the hydrogel electrolyte prepared in Example 1 of this invention.

[0022] Figure 2 This is a cyclic voltammetry curve of the zinc ion hybrid capacitor assembled in Embodiment 1 of the present invention at different scan rates.

[0023] Figure 3 This is a charge-discharge curve of the zinc-ion hybrid capacitor prepared in Example 1 of the present invention under different current densities.

[0024] Figure 4 This is a charge-discharge curve of the zinc-ion hybrid capacitor prepared in Example 1 of the present invention under different degrees of deformation.

[0025] Figure 5 This is a charge-discharge curve of the zinc ion hybrid capacitor prepared in Example 1 of the present invention at room temperature and low temperature.

[0026] Figure 6This is an AC impedance curve of the zinc ion hybrid capacitor prepared in Example 1 of the present invention.

[0027] Figure 7 This is a cyclic voltammetry curve of the zinc ion hybrid capacitor assembled in Embodiment 2 of the present invention at different scan rates.

[0028] Figure 8 This is a charge-discharge curve of the zinc-ion hybrid capacitor prepared in Example 2 of the present invention under different current densities.

[0029] Figure 9 This is the AC impedance curve of the zinc ion hybrid capacitor prepared in Example 2 of the present invention.

[0030] Figure 10 This is a cyclic voltammetry curve of the zinc ion hybrid capacitor assembled in Embodiment 3 of the present invention at different scan rates.

[0031] Figure 11 This is a charge-discharge curve of the zinc-ion hybrid capacitor prepared in Example 3 of the present invention under different current densities.

[0032] Figure 12 This is the AC impedance curve of the zinc ion hybrid capacitor prepared in Example 3 of the present invention.

[0033] Figure 13 This is a cyclic voltammetry curve of the zinc ion hybrid capacitor assembled in Embodiment 4 of the present invention at different scan rates.

[0034] Figure 14 This is a charge-discharge curve of the zinc-ion hybrid capacitor prepared in Example 4 of the present invention under different current densities.

[0035] Figure 15 This is the AC impedance curve of the zinc ion hybrid capacitor prepared in Example 4 of the present invention. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0037] Example 1

[0038] (1) Dissolve 8.29g of 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 0.72g of acrylic acid (AA), 3.408g of zinc chloride (ZnCl2), 0.052g of ferric chloride (FeCl3), and 2.035g of zinc oxide in 20mL of deionized water (i.e., disperse evenly) and stir magnetically for 30min until the liquid is clear.

[0039] (2) The product from step (1) was filtered to obtain a liquid portion, and 10 mg of 2-ketoglutaric acid was added and magnetically stirred until completely dissolved. The liquid was then dropped into a tetrafluoroethylene mold and polymerized under 365 nm ultraviolet light for 30 min to obtain a hydrogel electrolyte for a zinc ion mixed capacitor.

[0040] (3) Disperse 160 mg of activated carbon and 20 mg of carbon black in 5 mL of ethanol and sonicate for 30 min. Cut a 3 cm × 2 cm piece of carbon cloth, coat the above mixture evenly on the carbon cloth, and dry it in a 60 °C oven for 30 min to obtain the cathode material.

[0041] (4) Cut a 3cm×2cm zinc foil and grind the surface to remove the oxide layer to use as the anode material.

[0042] (5) Assemble the anode material, hydrogel electrolyte and cathode material into a sandwich structure to prepare a zinc ion mixed capacitor.

[0043] The hydrogel electrolyte structure was characterized using a cold field emission scanning electron microscope (S4800). Figure 1 It can be clearly seen that the prepared hydrogel electrolyte exhibits a porous structure after freeze-drying, proving that it has a three-dimensional network of ion transport channels as an electrolyte, which is beneficial for ion transport.

[0044] The zinc-ion hybrid capacitor was tested using cyclic voltammetry with a Shanghai Chenhua CHI660E electrochemical workstation. Cyclic voltammetry was employed to detect the integrated supercapacitor (i.e., the zinc-ion hybrid capacitor prepared in Example 1) at voltammetry rates of 10 mV / s, 20 mV / s, 50 mV / s, 100 mV / s, and 200 mV / s. The obtained cyclic voltammetry curves are shown below. Figure 2 As shown, the zinc-ion hybrid capacitor can be charged and discharged normally within the voltage window of 0-1.8V.

[0045] The energy storage performance of the zinc-ion hybrid capacitor was tested using a Shanghai Chenhua CHI660E electrochemical workstation with charge-discharge curves. The tests were conducted at 10 A g. -1 5A g -1 ,3A g -1 ,2A g -1 1A g -1 The charge-discharge curves obtained under the current density are as follows: Figure 3 As shown, the specific capacitances obtained are as follows:

[0046] <![CDATA[Current density (A g -1 )]]> 1 2 3 5 10 <![CDATA[Specific capacitance (F g -1 )]]> 458.75 308.49 234.37 180.62 145.62

[0047] The flexibility of the zinc-ion hybrid capacitor was characterized using a Shanghai Chenhua CHI660E electrochemical workstation. Figure 4The charge-discharge curves of the zinc-ion hybrid capacitor under different deformation states show that the hybrid capacitor exhibits good performance under twisting and 90-degree bending. 0 ), folding 180 degrees 0 All of them exhibit the same charge-discharge curves, which are basically consistent with the curves in the initial state, demonstrating their excellent flexibility.

[0048] The low-temperature performance of the zinc-ion hybrid capacitor was characterized using a Shanghai Chenhua CHI660E electrochemical workstation. The prepared capacitors were placed in atmospheres at corresponding temperatures, such as 0℃ and -18℃, for insulation before performance testing. Figure 5 The charge-discharge curves of the zinc-ion hybrid capacitor at 25℃, 0℃, and -18℃ show that it can still operate normally at low temperatures, exhibiting excellent low-temperature resistance. Calculations show that the zinc-ion hybrid capacitor retains 78.9% and 55.5% of its initial capacitance at 0℃ and -18℃, respectively.

[0049] The AC impedance of the zinc ion mixed capacitor was characterized using a Shanghai Chenhua CHI660E electrochemical workstation. Figure 6 It can be seen that the EIS curve shows an approximately semi-circular shape in the high-frequency region, controlled by charge transfer behavior, and an approximately straight line in the low-frequency region, controlled by diffusion behavior. The charge transfer resistance is 5 ohms, which is beneficial to improving electrochemical performance.

[0050] Example 2

[0051] (1) Dissolve 8.29g of 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 0.72g of acrylic acid (AA), 6.815g of zinc chloride (ZnCl2), 0.052g of ferric chloride (FeCl3), and 2.035g of zinc oxide in 20mL of deionized water and stir magnetically for 30min until the liquid is clear.

[0052] (2) The product from step (1) was filtered to obtain a liquid portion, and 10 mg of 2-ketoglutaric acid was added and magnetically stirred until completely dissolved. The liquid was then dropped into a tetrafluoroethylene mold and polymerized under 365 nm ultraviolet light for 30 min to obtain a hydrogel electrolyte for a zinc ion mixed capacitor.

[0053] (3) Disperse 160 mg of activated carbon and 20 mg of carbon black in 5 mL of ethanol and sonicate for 30 min. Cut a 3 cm × 2 cm piece of carbon cloth, coat the above mixture evenly on the carbon cloth, and dry it in a 60 °C oven for 30 min to obtain the cathode material.

[0054] (4) Cut a 3cm×2cm zinc foil and grind the surface to remove the oxide layer to use as the anode material.

[0055] (5) Assemble the anode material, hydrogel electrolyte and cathode material into a sandwich structure to prepare a zinc ion mixed capacitor.

[0056] This embodiment aims to improve electrochemical performance by increasing the amount of zinc chloride added during the preparation of the hydrogel electrolyte, thereby increasing the zinc ion concentration in the electrolyte. However, the actual electrochemical performance did not change significantly, and even decreased slightly.

[0057] The zinc-ion hybrid capacitor was tested using cyclic voltammetry with a Shanghai Chenhua CHI660E electrochemical workstation. The integrated supercapacitor was detected at voltammetry rates of 10 mV / s, 20 mV / s, 50 mV / s, 100 mV / s, and 200 mV / s. The obtained cyclic voltammetry curves are shown below. Figure 7 As shown, the zinc-ion hybrid capacitor can be charged and discharged normally within the voltage window of 0-1.8V.

[0058] The energy storage performance of the zinc-ion hybrid capacitor was tested using a Shanghai Chenhua CHI660E electrochemical workstation with charge-discharge curves. The tests were conducted at 10 A g. -1 5A g -1 ,3A g -1 ,2A g -1 1A g -1 The charge-discharge curves obtained under the current density are as follows: Figure 8 As shown, the specific capacitance obtained is lower than that in Example 1, specifically:

[0059] <![CDATA[Current density (Ag -1 )]]> 1 2 3 5 10 <![CDATA[Specific capacitance (F g -1 )]]> 378.13 307.75 239.13 173.43 105.63

[0060] The AC impedance of the zinc ion mixed capacitor was characterized using a Shanghai Chenhua CHI660E electrochemical workstation. Figure 9 It can be seen that the EIS curve shows an approximately semi-circular shape in the high-frequency region, controlled by charge transfer behavior, and an approximately straight line in the low-frequency region, controlled by diffusion behavior. The charge transfer resistance is 3 ohms, which is slightly lower than that in Example 1.

[0061] Example 3

[0062] (1) Dissolve 8.29g of 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 0.72g of acrylic acid (AA), 1.704g of zinc chloride (ZnCl2), 0.052g of ferric chloride (FeCl3), and 2.035g of zinc oxide in 20mL of deionized water and stir magnetically for 30min until the liquid is clear.

[0063] (2) The product from step (1) was filtered to obtain a liquid portion, and 10 mg of 2-ketoglutaric acid was added and magnetically stirred until completely dissolved. The liquid was then dropped into a tetrafluoroethylene mold and polymerized under 365 nm ultraviolet light for 30 min to obtain a hydrogel electrolyte for a zinc ion mixed capacitor.

[0064] (3) Disperse 160 mg of activated carbon and 20 mg of carbon black in 5 mL of ethanol and sonicate for 30 min. Cut a 3 cm × 2 cm piece of carbon cloth, coat the above mixture evenly on the carbon cloth, and dry it in a 60 °C oven for 30 min to obtain the cathode material.

[0065] (4) Cut a 3cm×2cm zinc foil and grind the surface to remove the oxide layer to use as the anode material.

[0066] (5) Assemble the anode material, hydrogel electrolyte and cathode material into a sandwich structure to prepare a zinc ion mixed capacitor.

[0067] This embodiment aims to improve electrochemical performance by increasing the amount of zinc chloride added during the preparation of the hydrogel electrolyte, thereby increasing the zinc ion concentration in the electrolyte. However, the actual electrochemical performance did not change significantly, and even decreased slightly.

[0068] The zinc-ion hybrid capacitor was tested using cyclic voltammetry with a Shanghai Chenhua CHI660E electrochemical workstation. The integrated supercapacitor was detected at voltammetry rates of 10 mV / s, 20 mV / s, 50 mV / s, 100 mV / s, and 200 mV / s. The obtained cyclic voltammetry curves are shown below. Figure 10 As shown, the zinc-ion hybrid capacitor can be charged and discharged normally within the voltage window of 0-1.8V.

[0069] The energy storage performance of the zinc-ion hybrid capacitor was tested using a Shanghai Chenhua CHI660E electrochemical workstation with charge-discharge curves. The tests were conducted at 10 A g. -1 5A g -1 ,3A g -1 ,2A g -1 1A g -1 The charge-discharge curves obtained under the current density are as follows: Figure 11 As shown, the obtained specific capacitance is relatively low, as follows:

[0070] <![CDATA[Current density (Ag -1 )]]> 1 2 3 5 10 <![CDATA[Specific capacitance (F g -1 )]]> 81.63 54.75 44.83 35.63 35

[0071] The AC impedance of the zinc ion mixed capacitor was characterized using a Shanghai Chenhua CHI660E electrochemical workstation. Figure 12It can be seen that the EIS curve shows an approximately semi-circular shape in the high-frequency region, controlled by charge transfer behavior, and an approximately straight line in the low-frequency region, controlled by diffusion behavior. The charge transfer resistance is 5.2 ohms, which is not much different from that in Example 1.

[0072] Example 4

[0073] (1) Dissolve 8.29g of 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 0.72g of acrylic acid (AA), 0.052g of ferric chloride (FeCl3), and 2.035g of zinc oxide in 20mL of deionized water and stir magnetically for 30min until the liquid is clear.

[0074] (2) The product from step (1) was filtered to obtain a liquid portion, and 10 mg of 2-ketoglutaric acid was added and magnetically stirred until completely dissolved. The liquid was then dropped into a tetrafluoroethylene mold and polymerized under 365 nm ultraviolet light for 30 min to obtain a hydrogel electrolyte for a zinc ion mixed capacitor.

[0075] (3) Disperse 160 mg of activated carbon and 20 mg of carbon black in 5 mL of ethanol and sonicate for 30 min. Cut a 3 cm × 2 cm piece of carbon cloth, coat the above mixture evenly on the carbon cloth, and dry it in a 60 °C oven for 30 min to obtain the cathode material.

[0076] (4) Cut a 3cm×2cm zinc foil and grind the surface to remove the oxide layer to use as the anode material.

[0077] (5) Assemble the anode material, hydrogel electrolyte and cathode material into a sandwich structure to prepare a zinc ion mixed capacitor.

[0078] In this embodiment, the amount of zinc chloride added was adjusted to zero. The zinc-ion mixed capacitor was tested using cyclic voltammetry with a Shanghai Chenhua CHI660E electrochemical workstation. The integrated supercapacitor was detected at voltammetry rates of 10 mV / s, 20 mV / s, 50 mV / s, 100 mV / s, and 200 mV / s. The obtained cyclic voltammetry curves are shown below. Figure 13 As shown, the zinc-ion hybrid capacitor can be charged and discharged normally within the voltage window of 0-1.8V.

[0079] The energy storage performance of the zinc-ion hybrid capacitor was tested using a Shanghai Chenhua CHI660E electrochemical workstation with charge-discharge curves. The tests were conducted at 10 A g. -1 5A g -1 ,3A g -1 ,2A g -1 1A g -1 The charge-discharge curves obtained under the current density are as follows: Figure 14 As shown. The obtained specific capacitances are relatively low, as follows:

[0080]

[0081]

[0082] The AC impedance of the zinc ion mixed capacitor was characterized using a Shanghai Chenhua CHI660E electrochemical workstation. Figure 15 It can be seen that the EIS curve shows an approximately semi-circular shape in the high-frequency region, controlled by charge transfer behavior, and an approximately straight line in the low-frequency region, controlled by diffusion behavior. The charge transfer resistance is 12.5 ohms, which is higher than that of Example 1.

[0083] Example 5

[0084] (1) Dissolve 8.29g of 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 0.18g of acrylic acid (AA), 3.408g of zinc chloride (ZnCl2), 0.052g of ferric chloride (FeCl3), and 1.729g of zinc oxide in 20mL of deionized water and stir magnetically for 30min until the liquid is clear.

[0085] (2) The product from step (1) was filtered to obtain a liquid portion, and 10 mg of 2-ketoglutaric acid was added and magnetically stirred until completely dissolved. The liquid was then dropped into a tetrafluoroethylene mold and polymerized under 365 nm ultraviolet light for 30 min to obtain a hydrogel electrolyte for a zinc ion mixed capacitor.

[0086] (3) Disperse 160 mg of activated carbon and 20 mg of carbon black in 5 mL of ethanol and sonicate for 30 min. Cut a 3 cm × 2 cm piece of carbon cloth, coat the above mixture evenly on the carbon cloth, and dry it in a 60 °C oven for 30 min to obtain the cathode material.

[0087] (4) Cut a 3cm×2cm zinc foil and grind the surface to remove the oxide layer to use as the anode material.

[0088] (5) Assemble the anode material, hydrogel electrolyte and cathode material into a sandwich structure to prepare a zinc ion mixed capacitor.

[0089] This comparative study aimed to reduce the amount of AA added and increase the proportion of AMPS in the hydrogel electrolyte to increase the proportion of sulfonic acid groups with better ionic compatibility in the system, thereby improving electrochemical performance. However, the reduction of AA monomers resulted in poorer hydrogel electrolyte molding and difficulty in assembly, making it impractical for real-world applications.

[0090] By adjusting the process parameters according to the content of this invention, the highly flexible, low-temperature resistant zinc-ion hybrid capacitor of this invention can be prepared, exhibiting performance substantially consistent with the embodiments. The invention has been described above as exemplary. It should be noted that any simple modifications, alterations, or other equivalent substitutions that can be made by those skilled in the art without creative effort, without departing from the core of this invention, fall within the protection scope of this invention.

Claims

1. A highly flexible, low-temperature resistant zinc-ion hybrid capacitor, characterized in that, The overall structure is a sandwich structure, using a hydrogel electrolyte, wherein the hydrogel electrolyte is a copolymer hydrogel of monomers 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid, and the molar ratio of acrylic acid to 2-acrylamide-2-methylpropanesulfonic acid is (1:1) to (1:4); zinc chloride, ferric chloride and zinc oxide are added to the copolymer hydrogel, and the molar ratio of zinc chloride to the two monomers is (0.2-1):1, the molar ratio of ferric chloride to the two monomers is (5-8):100, and the molar ratio of zinc oxide to the two monomers is (0.8-1):

2.

2. The highly flexible, low-temperature resistant zinc-ion hybrid capacitor according to claim 1, characterized in that, The anode is zinc foil; the cathode is carbon cloth uniformly coated with activated carbon and carbon black, with a mass ratio of activated carbon to carbon black of (6-8):

1.

3. A highly flexible, low-temperature resistant zinc-ion hybrid capacitor according to claim 1 or 2, characterized in that, The molar ratio of acrylic acid to 2-acrylamide-2-methylpropanesulfonic acid is (1:1) to (1:3).

4. A highly flexible, low-temperature resistant zinc-ion hybrid capacitor according to claim 1 or 2, characterized in that, The molar ratio of zinc chloride to the two monomers is (0.5-1):

1.

5. A highly flexible, low-temperature resistant zinc-ion hybrid capacitor according to claim 1 or 2, characterized in that, The molar ratio of ferric chloride to the two monomers is (6-8):

100.

6. A highly flexible, low-temperature resistant zinc-ion hybrid capacitor according to claim 1 or 2, characterized in that, The molar ratio of zinc oxide to the two monomers is 1:

2.

7. A method for preparing a highly flexible, low-temperature resistant zinc-ion hybrid capacitor, characterized in that, Follow these steps: Step 1: 2-Acrylamide-2-methylpropanesulfonic acid, acrylic acid, zinc chloride, ferric chloride, and zinc oxide are uniformly dispersed in deionized water, filtered to obtain a clear solution, and an initiator is added to initiate polymerization to obtain a hydrogel electrolyte. Step 2: Activated carbon and carbon black are ultrasonically dispersed in ethanol, then uniformly coated onto carbon cloth, and dried to obtain the cathode material; the zinc foil surface is polished to remove the oxide layer and used as the anode material. Step 3: Assemble the anode material, hydrogel electrolyte, and cathode material into a sandwich structure to prepare a zinc ion hybrid capacitor.

8. The method for preparing a highly flexible, low-temperature resistant zinc-ion hybrid capacitor according to claim 7, characterized in that, In step 1, 2-ketoglutaric acid was selected as the initiator, and the hydrogel electrolyte was obtained by polymerization under ultraviolet irradiation.

9. The method for preparing a highly flexible, low-temperature resistant zinc-ion hybrid capacitor according to claim 7, characterized in that, In step 1, the clarified solution is dropped into a tetrafluoroethylene mold for polymerization, and the ultraviolet irradiation time is 0.5 h.

10. The application of a highly flexible, low-temperature resistant zinc-ion hybrid capacitor as described in any one of claims 1-6 in energy storage, characterized in that, In 1Ag -1 The specific capacitance at the current density is 458.75 F g. -1 In 2Ag -1 The specific capacitance at current density is 308.49 F g. -1 In 3Ag -1 The specific capacitance at the current density is 234.37 F g. -1 In 5Ag -1 The specific capacitance at the current density is 180.62 F g. -1 In 10Ag -1 The specific capacitance at the current density is 145.62 F g. -1 It exhibits the same charge-discharge curves under torsion, bending at 90 degrees, and bending at 180 degrees; and retains 78.9% and 55.5% of its initial capacity at 0℃ and -18℃, respectively.

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