A supercapacitor with high specific surface area and its preparation method

Abstract

This invention discloses a supercapacitor with a high specific surface area and its preparation method, relating to the field of supercapacitor technology. The method includes: performing layer-by-layer cladding forming on TC4 alloy powder to obtain a three-dimensional biomimetic surface structure with a Gyroid topology in a three-period minimal surface; forming randomly distributed microscopic columnar protrusions on the surface of the three-dimensional biomimetic surface structure as a metal current collector; continuously depositing polyaniline along the three-dimensional biomimetic surface structure and its surface microscopic columnar protrusions using pulsed electrodeposition to obtain a TC4@PANI electrode; preparing a PVA-g-TMAC polymer by grafting polyvinyl alcohol with an epoxy compound containing quaternary ammonium groups under alkaline conditions; preparing a PVA-g-TMAC hydrogel electrolyte and injecting it into a mold; arranging two TC4@PANI electrodes at a predetermined interval in the mold and sandwiching the three-dimensional biomimetic surface structure; and obtaining a sandwich-structured supercapacitor through freeze-thaw solidification.

Description

Technical Field

[0001] This invention relates to the field of supercapacitor technology, and in particular to a supercapacitor with a high specific surface area and its preparation method. Background Technology

[0002] While supercapacitors offer advantages such as high power density and long lifespan, existing electrodes are mostly planar current collectors or conventional porous frameworks supporting active materials, which generally suffer from limited effective specific surface area and insufficient utilization of three-dimensional channels. When depositing conductive polymers on complex three-dimensional frameworks, discontinuous deposition, local accumulation, and channel blockage are prone to occur, leading to longer ion transport paths, increased internal resistance, and decreased rate performance. When gel / hydrogel electrolytes have insufficient adhesion or unstable contact at the electrode interface, interfacial contact resistance is easily formed, causing cycling fluctuations. Therefore, increasing the specific surface area, constructing a continuous conductive layer, and achieving integrated electrode-electrolyte bonding while maintaining channel connectivity remain key technical challenges. Summary of the Invention

[0003] In view of this, this application provides a supercapacitor with high specific surface area and a method for its preparation.

[0004] According to one aspect of this disclosure, a method for fabricating a supercapacitor with a high specific surface area is provided, comprising: layer-by-layer cladding forming of TC4 alloy powder to obtain a three-dimensional biomimetic surface structure with a Gyroid topology in a three-period minimal surface, and forming randomly distributed microscopic columnar protrusions on the surface of the three-dimensional biomimetic surface structure as a metal current collector; continuously depositing polyaniline along the contour of the three-dimensional biomimetic surface structure of the metal current collector and its surface microscopic columnar protrusions using pulsed electrodeposition, and forming a continuous coating layer of polyaniline on the surface of the metal current collector while maintaining three-dimensional channel connectivity to obtain a TC4@PANI electrode; and then, under alkaline conditions... PVA-g-TMAC polymer is prepared by grafting polyvinyl alcohol with an epoxy compound containing quaternary ammonium groups. The PVA-g-TMAC polymer is dissolved in water to obtain PVA-g-TMAC hydrogel, which is then injected into a mold. Two TC4@PANI electrodes are arranged in the mold at a predetermined interval, and a biomimetic curved structure is placed in the middle position between the two TC4@PANI electrodes. The assembled mold is subjected to low-temperature freezing and then restored to room temperature. During the freeze-thaw process, the PVA-g-TMAC hydrogel, the two TC4@PANI electrodes, and the middle three-dimensional biomimetic curved structure are integrally solidified to form a sandwich structure, which serves as a supercapacitor.

[0005] According to another aspect of this disclosure, a supercapacitor with a high specific surface area is provided, characterized in that it includes a pair of TC4@PANI electrodes, a three-dimensional biomimetic curved surface structure disposed between the two TC4@PANI electrodes, and a PVA-g-TMAC hydrogel electrolyte layer filling the space between the two TC4@PANI electrodes and covering the three-dimensional biomimetic curved surface structure.

[0006] The beneficial effects of this invention are as follows: A three-dimensional biomimetic curved surface structure with Gyroid topology and its random microscopic columnar protrusions are used as metal current collectors to increase the effective interface area and maintain pore connectivity. Combined with pulsed electrodeposition, polyaniline is continuously deposited along the three-dimensional contour to form a continuous coating layer, thus balancing electron channel continuity and electrolyte wettability. Simultaneously, paired TC4@PANI electrodes and an intermediate three-dimensional biomimetic curved surface structure are arranged within the mold, and PVA-g-TMAC hydrogel is introduced. After freeze-thaw solidification, an integral sandwich structure is formed, enabling the electrolyte layer and the electrode / intermediate structure to achieve integrated bonding and stable interface contact, reducing interface contact resistance and improving charge / discharge response and cycle stability, thereby achieving a comprehensive improvement in both specific surface area and structural consistency. Attached Figure Description

[0007] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a schematic diagram of a supercapacitor with a high specific surface area.

[0009] Figure 2 This is a flowchart for preparing the TC4@PANI electrode.

[0010] Figure 3 The flowchart for preparing PVA-g-TMAC hydrogel.

[0011] Figure 4 A flowchart for assembling a sandwich-structured symmetrical supercapacitor.

[0012] In the figure: 1-Laser powder bed melting equipment; 2-Three-dimensional biomimetic curved surface structure; 3-Polyaniline electrodeposition solution; 4-TC4@PANI electrode; 5-Pulse electrodeposition equipment; 6-TC4 alloy powder; 7-Microscopic columnar protrusion structure; 8-Gyroid topology; 9-Alkaline conditions; 10-Epoxy compound containing quaternary ammonium groups; 11-Feeding and reaction conditions; 12-PVA-g-TMAC polymer; 13-Deionized water; 14-PVA-g-TMAC hydrogel; 15-Polyvinyl alcohol; 16-Supercapacitor; 17-Cryogenic freezing; 18-Ceramic mold. Detailed Implementation

[0013] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0014] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0015] This invention provides a supercapacitor with a high specific surface area and its preparation method, comprising: layer-by-layer cladding forming of TC4 alloy powder 6 to obtain a three-dimensional biomimetic surface structure 2 with a Gyroid topology 8 in a three-period minimal surface, and forming randomly distributed microscopic columnar protrusion structures 7 on the surface of the three-dimensional biomimetic surface structure 2 as a metal current collector; continuously depositing polyaniline along the contour of the three-dimensional biomimetic surface structure 2 of the metal current collector and its surface microscopic columnar protrusions using pulsed electrodeposition, and forming a continuous coating layer of polyaniline on the surface of the metal current collector while maintaining three-dimensional channel connectivity to obtain a TC4@PANI electrode 4; and reacting polyvinyl alcohol 15 with quaternary ammonium under alkaline conditions 9. A grafting reaction is performed on the epoxy compound 10 of the group to obtain a PVA-g-TMAC polymer 12. The PVA-g-TMAC polymer 12 is dissolved in water to obtain a PVA-g-TMAC hydrogel 14, which is then injected into a mold 18. Two TC4@PANI electrodes 4 are arranged in the mold 18 at a predetermined interval, and the biomimetic curved structure is placed in the middle position between the two TC4@PANI electrodes 4. The assembled mold 18 is subjected to low temperature freezing 17 and then restored to room temperature, so that the PVA-g-TMAC hydrogel 14 is solidified with the two TC4@PANI electrodes 4 and the middle three-dimensional biomimetic curved structure 2 during the freeze-thaw process to form a sandwich structure, which serves as a supercapacitor 16.

[0016] Preferably, when performing layer-by-layer cladding forming of TC4 alloy powder 6, a laser powder bed melting device 1 is used, with the Gyroid topology 8 in the three-period minimal surface as the target structure for trajectory scanning control, so that the channels of the three-dimensional biomimetic surface structure 2 are connected, and during and / or after forming, the scanning path is adjusted and the surface microstructure construction process is used to form randomly distributed microscopic columnar protrusion structures 7 on the surface of the biomimetic surface structure, and the three-dimensional biomimetic surface structure 2 as a whole is used as a metal current collector.

[0017] Preferably, the pulse electrodeposition method refers to using a metal current collector as a working electrode, immersing it in a polyaniline electrodeposition solution 3, and using a pulse electrodeposition device 5 to deposit polyaniline on the three-dimensional biomimetic curved surface structure 2 and its surface micro-columnar protrusion structure 7, so that the polyaniline grows continuously along the three-dimensional contour and forms a continuous coating layer on the surface of the metal current collector.

[0018] Preferably, the predetermined spacing is 18~25mm.

[0019] Preferably, the temperature of the low-temperature freezing 17 is -70℃ to -80℃ and the freezing time is 15 to 25 minutes.

[0020] The present invention also provides a supercapacitor with a high specific surface area, including a pair of TC4@PANI electrodes 4, a three-dimensional biomimetic curved surface structure 2 disposed between the two TC4@PANI electrodes 4, and a PVA-g-TMAC hydrogel 14 electrolyte layer filled between the two TC4@PANI electrodes 4 and covering the three-dimensional biomimetic curved surface structure 2.

[0021] In some embodiments of this application, the three-dimensional biomimetic curved surface structure 2 is made of titanium alloy and has a three-dimensional porous structure with a Gyroid topology 8, with multiple microscopic columnar protrusions randomly distributed on its surface.

[0022] In some embodiments of this application, the effective electrode surfaces of the two TC4@PANI electrodes 4 are arranged opposite each other and spaced apart by a predetermined distance.

[0023] In Example 1, TC4 alloy powder 6 was subjected to layer-by-layer cladding under an inert atmosphere. The laser power of the laser powder bed melting equipment 1 was set to 156W, the scanning speed to 1285mm / s, the layer thickness to 40μm, and the spot diameter to 57μm. A three-dimensional biomimetic curved surface structure 2 of Gyroid topology 8 was obtained, and its surface was formed with randomly distributed microscopic columnar protrusions. The Gyroid unit size of the formed structure was 1.18mm, the porosity was 79.1%, the height of the columnar protrusions was 41.7μm, and the diameter of the columnar protrusions was 8.0μm. This structure was used as a metal current collector. In the polyaniline electrodeposition solution 3, pulsed electrodeposition was used to continuously deposit polyaniline along the three-dimensional contour to form a film. The pulse current density was... With a capacitance of 2.08 A / dm², a duty cycle of 0.29, a frequency of 106 Hz, and a deposition cutoff charge of 9.5 C, a TC4@PANI electrode 4 was formed with a polyaniline loading of 1.46 mg / cm². A PVA-g-TMAC polymer 12 was prepared, and its grafting degree was controlled to be 12.8% under the feeding and reaction conditions 11. PVA-g-TMAC was dissolved in deionized water 13 to prepare a 6.2 wt% hydrogel electrolyte. Two TC4@PANI electrodes 4 were placed in a mold 18 with an electrode spacing of 22.3 mm. The three-dimensional biomimetic curved surface structure 2 was arranged between the two electrodes and hydrogel was poured in. After freezing at −75℃ for 20.4 min, the mixture was refrigerated for 10 min to solidify, thus obtaining a sandwich structure supercapacitor 16.

[0024] Example 2: A three-dimensional biomimetic curved surface structure 2 was prepared according to the layer-by-layer cladding route of Example 1. The laser power of the laser powder bed melting equipment 1 was set to 198W, the scanning speed to 1462mm / s, the layer thickness to 38μm, and the spot diameter to 52μm, resulting in a Gyroid unit size of 0.96mm, a porosity of 84.0%, a columnar protrusion height of 58.3μm, and a columnar protrusion diameter of 10.1μm. A continuous polyaniline film layer was formed by pulsed electrodeposition in the polyaniline electrodeposition solution 3. With a flux density of 2.22 A / dm², a duty cycle of 0.26, a frequency of 111 Hz, a deposition cutoff charge of 10.3 C, and a polyaniline loading of 2.52 mg / cm², a PVA-g-TMAC with a grafting degree of 18.1% was prepared and an 8.0 wt% hydrogel electrolyte was formulated. Two TC4@PANI electrodes 4 were assembled at a spacing of 19.6 mm, and a three-dimensional biomimetic curved surface structure 2 was sandwiched between them before hydrogel was injected. After freezing at −78℃ for 18.2 min and then thawing and solidifying for 10 min, a sandwich structure supercapacitor 16 was obtained.

[0025] Example 3: A three-dimensional biomimetic curved surface structure 2 was prepared according to the layer-by-layer cladding route of Example 1. The laser power of the laser powder bed melting equipment 1 was set to 184W, the scanning speed to 1398mm / s, the layer thickness to 37μm, and the spot diameter to 54μm, resulting in a Gyroid unit size of 1.06mm, a porosity of 82.7%, a columnar protrusion height of 52.4μm, and a columnar protrusion diameter of 9.3μm. A continuous polyaniline coating layer was formed using pulsed electrodeposition with a pulse current density of 2.35. A / dm², duty cycle 0.25, frequency 100Hz, deposition cutoff charge 11.8C, polyaniline loading 3.06mg / cm²; PVA-g-TMAC with grafting degree of 20.9% was prepared and 10.1wt% hydrogel electrolyte was prepared. Two TC4@PANI electrodes 4 were assembled at a spacing of 20.4mm and sandwiched with a three-dimensional biomimetic curved surface structure 2. After hydrogel was injected, the mixture was frozen at −80℃ for 16.7min and then refrigerated for 10min to obtain a sandwich structure supercapacitor 16.

[0026] Example 4: A three-dimensional biomimetic curved surface structure 2 was prepared according to the layer-by-layer cladding route of Example 1. The laser power of the laser powder bed melting equipment 1 was set to 236W, the scanning speed to 1720mm / s, the layer thickness to 36μm, and the spot diameter to 46μm, resulting in a Gyroid unit size of 0.82mm, a porosity of 87.5%, a columnar protrusion height of 68.6μm, and a columnar protrusion diameter of 12.0μm. A continuous polyaniline coating layer was formed using pulsed electrodeposition with a pulse current density of 2.5. With a capacitance of 7 A / dm², a duty cycle of 0.24, a frequency of 97 Hz, a deposition cutoff charge of 13.5 C, and a polyaniline loading of 3.58 mg / cm², a PVA-g-TMAC with a grafting degree of 24.0% was prepared and an 11.7 wt% hydrogel electrolyte was formulated. Two TC4@PANI electrodes 4 were assembled at a spacing of 18.2 mm and sandwiched with a three-dimensional biomimetic curved surface structure 2. After the hydrogel was injected, the electrode was frozen at −80℃ for 15.4 min and then refrigerated for 10 min to solidify, thus obtaining a sandwich structure supercapacitor 16.

[0027] Example 5: A three-dimensional biomimetic curved surface structure 2 was prepared according to the layer-by-layer cladding route of Example 1. The laser power of the laser powder bed melting equipment 1 was set to 176W, the scanning speed to 1368mm / s, the layer thickness to 39μm, and the spot diameter to 53μm, resulting in a Gyroid unit size of 1.01mm, a porosity of 83.3%, a columnar protrusion height of 55.1μm, and a columnar protrusion diameter of 9.7μm. A continuous polyaniline coating layer was formed using pulsed electrodeposition with a pulse current density of 2.26... A / dm², duty cycle 0.27, frequency 109Hz, deposition cutoff charge 11.2C, polyaniline loading 2.79mg / cm²; PVA-g-TMAC with grafting degree of 18.6% was prepared and 9.3wt% hydrogel electrolyte was prepared. Two TC4@PANI electrodes 4 were assembled at a spacing of 20.1mm and sandwiched with a three-dimensional biomimetic curved surface structure 2. After hydrogel was injected, the mixture was frozen at −79℃ for 17.1min and then refrigerated for 10min to obtain a sandwich structure supercapacitor 16.

[0028] Example 6: A three-dimensional biomimetic curved surface structure 2 was prepared according to the layer-by-layer cladding route of Example 1. The laser power of the laser powder bed melting equipment 1 was set to 224W, the scanning speed to 1628mm / s, the layer thickness to 36μm, and the spot diameter to 47μm, resulting in a Gyroid unit size of 0.90mm, a porosity of 86.0%, a columnar protrusion height of 64.2μm, and a columnar protrusion diameter of 11.1μm. A continuous polyaniline coating layer was formed using pulsed electrodeposition with a pulse current density of 2.44. A / dm², duty cycle 0.25, frequency 101Hz, deposition cutoff charge 12.8C, polyaniline loading 3.33mg / cm²; PVA-g-TMAC with grafting degree of 22.6% was prepared and 10.9wt% hydrogel electrolyte was prepared. Two TC4@PANI electrodes 4 were assembled at a spacing of 18.7mm and sandwiched with a three-dimensional biomimetic curved surface structure 2. After hydrogel was injected, the mixture was frozen at −80℃ for 15.6min and then refrigerated for 10min to obtain a sandwich structure supercapacitor 16.

[0029] Comparative Example 1: TC4@PANI electrode 4 and PVA-g-TMAC hydrogel 14 electrolyte were prepared according to the layer-by-layer cladding and pulse electrodeposition conditions of Example 4. The polyaniline loading was controlled at 3.60 mg / cm², the PVA-g-TMAC grafting degree was 24.0%, and the hydrogel concentration was 11.7 wt%. During the assembly stage, the three-dimensional biomimetic curved surface structure 2 was not arranged. The intermediate structure was replaced by a flat TC4 sheet in the mold 18 while maintaining an electrode spacing of 18.2 mm. After the hydrogel was poured in, the device was frozen at −80℃ for 15.4 min and then refrigerated for 10 min to obtain the comparative example device.

[0030] Comparative Example 2: A three-dimensional biomimetic curved surface structure 2 was obtained by layer-by-layer cladding forming according to Example 4, and a device was prepared under the same assembly and freeze-thaw solidification conditions. In the polyaniline deposition stage, a DC constant current electrodeposition method was used with a current density of 2.10 A / dm² and a deposition time of 26 min. The polyaniline loading was controlled at 3.56 mg / cm². The PVA-g-TMAC grafting degree was 24.0%, the hydrogel concentration was 11.7 wt%, the electrode spacing was 18.2 mm, and the device was frozen at −80℃ for 15.4 min and then thawed for 10 min to obtain the comparative example device.

[0031] Comparative Example 3: A three-dimensional biomimetic curved surface structure 2 and a TC4@PANI electrode 4 were prepared according to Example 4, with the polyaniline loading maintained at 3.58 mg / cm². No quaternary ammonium grafting reaction was performed during the electrolyte preparation stage. 12.0 wt% PVA hydrogel electrolyte was prepared using polyvinyl alcohol 15. The two TC4@PANI electrodes 4 were assembled at a spacing of 18.2 mm and sandwiched with the three-dimensional biomimetic curved surface structure 2. After PVA hydrogel was poured in, the device was frozen at −80℃ for 15.4 min and then refrigerated for 10 min to obtain the comparative example device.

[0032] Electrochemical performance testing and calculation methods:

[0033] Each sample was allowed to stand at 25℃ for 30 minutes before testing. A constant current charge-discharge method was used, with discharge tests conducted at current densities of 1 mA / cm² and 10 mA / cm² within a voltage window of 0–1.0V. Discharge current, discharge time, effective electrode area, and voltage drop were recorded. Sheet capacitance was calculated according to… Calculate, where, It is a surface capacitance. This is the discharge current. Discharge time, The effective area of ​​the electrode. For voltage drop;

[0034] The equivalent series resistance (ESR) is obtained by AC impedance testing. The ESR is taken as the real intercept in the high-frequency region and converted to (Ω·cm²) according to the effective area of ​​the electrode.

[0035] Effective thickness of device Five measuring points were selected within the effective area of ​​the electrode using a digital thickness gauge, and the average value was taken. = As effective volume; according to The volume capacitance is obtained.

[0036] Energy density according to Calculation, where The upper limit of the test voltage window; power density is calculated according to... Calculation, where The discharge time is taken under the condition of 10mA / cm².

[0037] Cyclic testing was performed at 10 mA / cm² for 10,000 charge-discharge cycles. The sheet capacitance was recorded on the first and 10,000th cycles and then adjusted according to the retention rate. Calculate the cycle retention rate; the coulombic efficiency is converted as the ratio of discharge time to charging time.

[0038] Each sample group was prepared independently three times, and Table 2 shows the mean ± standard deviation.

[0039] Table 1. Comparison of structural and process parameters between the examples and comparative examples:

[0040] sample Gyroid unit size (mm) Porosity (%) Height of columnar protrusion (µm) Diameter of columnar protrusion (µm) Polyaniline loading (mg / cm²) PVA-g-TMAC grafting degree (%) Hydrogel concentration (wt%) Electrode spacing (mm) Freezing temperature (°C) Freezing time (min) Example 1 1.18 79.1 41.7 8 1.46 12.8 6.2 22.3 -75 20.4 Example 2 0.96 84 58.3 10.1 2.52 18.1 8 19.6 -78 18.2 Example 3 1.06 82.7 52.4 9.3 3.06 20.9 10.1 20.4 -80 16.7 Example 4 0.82 87.5 68.6 12 3.58 24 11.7 18.2 -80 15.4 Example 5 1.01 83.3 55.1 9.7 2.79 18.6 9.3 20.1 -79 17.1 Example 6 0.9 86 64.2 11.1 3.33 22.6 10.9 18.7 -80 15.6 Comparative Example 1 - - - - 3.6 24 11.7 18.2 -80 15.4 Comparative Example 2 0.82 87.5 68.6 12 3.56 24 11.7 18.2 -80 15.4 Comparative Example 3 0.82 87.5 68.6 12 3.58 0 12 18.2 -80 15.4

[0041] As shown in Table 1, the differences between the embodiments and the comparative examples lie in four reproducible experimental conditions: structure, deposition, electrolyte, and assembly / consolidation. On the structure side, the effective interface area and pore morphology of the three-dimensional current collector are characterized by the size of the Gyroid unit, porosity, and the size of the microscopic columnar protrusions. On the deposition side, the continuity of the active layer and the degree of pore retention are characterized by the deposition method and the polyaniline loading. On the electrolyte side, the ion migration and interfacial bonding stability are characterized by the PVA-g-TMAC grafting degree and the hydrogel concentration. On the assembly / consolidation side, the internal wetting and molding consistency of the device are characterized by the electrode spacing and freezing conditions. The three comparative examples respectively address the three key differences: removal of the intermediate three-dimensional biomimetic curved surface structure 2, pulsed deposition replaced by DC deposition, and PVA-g-TMAC replaced by PVA hydrogel, allowing performance differences to be attributed to corresponding distinguishing features.

[0042] Table 2. Comparison of electrochemical performance between examples and comparative examples (n=3, mean ± standard deviation):

[0043] sample Shear capacitance @ 1mA / cm² (F / cm²) Shear capacitance @ 10mA / cm² (F / cm²) Ratio retention rate (10 / 1, %) Equivalent series resistance ESR (Ω·cm²) Energy density (1 mA, mWh / cm³) Power density (10 mA, mW / cm³) Cycle retention rate (10,000 cycles, %) Coulomb efficiency (%, steady state) Example 1 0.790±0.015 0.659±0.027 83.4±0.6 1.781±0.053 8.25±0.23 146.2±5.0 90.0±0.5 97.33±0.24 Example 2 1.042±0.016 0.881±0.015 84.5±1.0 1.691±0.039 10.92±0.43 176.4±5.5 89.7±0.5 97.26±0.14 Example 3 1.137±0.028 0.946±0.016 83.2±0.9 1.663±0.034 11.62±0.41 191.1±3.7 90.2±0.5 97.30±0.22 Example 4 1.223±0.029 0.933±0.026 76.3±0.9 1.571±0.050 12.56±0.21 206.5±3.9 89.5±0.6 97.59±0.19 Example 5 1.103±0.018 0.925±0.016 83.9±0.7 1.723±0.028 11.34±0.20 183.6±6.4 89.3±0.6 97.73±0.08 Example 6 1.176±0.016 0.987±0.025 84.0±1.0 1.642±0.048 11.48±0.41 202.7±5.1 89.6±0.4 97.41±0.20 Comparative Example 1 0.884±0.016 0.693±0.023 78.4±0.8 1.919±0.022 8.06±0.44 121.4±7.2 84.5±0.8 97.12±0.25 Comparative Example 2 1.176±0.033 0.857±0.02 72.9±1.0 1.862±0.036 12.04±0.43 160.3±5.4 85.0±0.9 96.83±0.11 Comparative Example 3 1.198±0.033 0.829±0.027 69.2±1.0 1.953±0.052 11.82±0.31 156.1±3.7 85.6±0.7 96.91±0.22

[0044] As shown in Table 2, under the same test conditions and calculation caliber, the example group maintained a high rate retention rate and a low ESR while increasing the surface capacitance. When the intermediate three-dimensional biomimetic curved surface structure 2 was removed in Comparative Example 1, the surface capacitance and power density decreased and the cycle retention rate decreased due to the reduction in effective interface area and pore connectivity. When pulse electrodeposition was replaced with DC constant current electrodeposition in Comparative Example 2, the uniformity of the active layer coverage on the complex surface decreased, and the rate retention rate and cycle retention rate decreased. When the quaternary ammonium grafting was removed and PVA hydrogel electrolyte was used in Comparative Example 3, the stability of ion transport and interfacial adhesion decreased, the ESR increased and the rate retention rate decreased.

Claims

1. A method for preparing a supercapacitor having a high specific surface area, characterized in that, The preparation method comprises, Step 1, layer-by-layer cladding forming is performed on TC4 alloy powder to obtain a three-dimensional biomimetic curved surface structure with a Gyroid topology in a three-period minimal surface, and a random distribution of microcolumnar protrusion structures is formed on the surface of the three-dimensional biomimetic curved surface structure as a metal current collector; Step 2, polyaniline is continuously deposited on the three-dimensional biomimetic curved surface structure and the profile of the microcolumnar protrusions on the surface of the metal current collector in a pulse electrodeposition manner to form a film, and the polyaniline forms a continuous coating layer on the surface of the metal current collector and keeps the three-dimensional pores connected to obtain a TC4@PANI electrode; Step 3, polyvinyl alcohol is grafted with a quaternary ammonium group-containing epoxy compound under alkaline conditions to prepare a PVA-g-TMAC polymer, the PVA-g-TMAC polymer is dissolved in water to obtain a PVA-g-TMAC hydrogel, the hydrogel is injected into a mold, two TC4@PANI electrodes are arranged in the mold at a predetermined interval, and the biomimetic curved surface structure is arranged at an intermediate position between the two TC4@PANI electrodes, the mold is subjected to low-temperature freezing and then restored to room temperature, and the PVA-g-TMAC hydrogel is integrally solidified with the two TC4@PANI electrodes and the intermediate three-dimensional biomimetic curved surface structure in a freeze-thaw process to form a sandwich structure as a supercapacitor.

2. The method for preparing a supercapacitor with high specific surface area as described in claim 1, characterized in that, When the layer-by-layer cladding forming is performed on the TC4 alloy powder, a laser powder bed melting equipment is used to perform trajectory scanning control with the Gyroid topology in a three-period minimal surface as a target structure, so that the three-dimensional biomimetic curved surface structure is connected with the pores, and the biomimetic curved surface structure is formed with a random distribution of microcolumnar protrusion structures on the surface through scanning path adjustment and surface microstructure construction during and / or after the forming.

3. The method of claim 2, wherein the supercapacitor having a high specific surface area is prepared by the steps of: The pulse electrodeposition manner refers to that the metal current collector is used as a working electrode, the metal current collector is immersed in a polyaniline electrodeposition solution, and a pulse electrodeposition equipment is used to deposit polyaniline on the three-dimensional biomimetic curved surface structure and the microcolumnar protrusion structure on the surface thereof, so that the polyaniline continuously grows along the three-dimensional profile and forms a continuous coating layer on the surface of the metal current collector. ​ 4. The method of claim 1 or 2, wherein the supercapacitor having a high specific surface area is prepared by the steps of: The predetermined interval is 18-25 mm. ​ 5. The method for preparing a supercapacitor with high specific surface area as described in claim 1 or 2, characterized in that, The low-temperature freezing is performed at a temperature of-70℃ to-80℃ for 15-25 min.

6. A supercapacitor with high specific surface area, prepared by the method of any one of claims 1 to 5. The supercapacitor comprises a pair of TC4@PANI electrodes, a three-dimensional biomimetic curved surface structure arranged between the two TC4@PANI electrodes, and a PVA-g-TMAC hydrogel electrolyte layer filled between the two TC4@PANI electrodes and covering the three-dimensional biomimetic curved surface structure.

7. The supercapacitor with high specific surface area as claimed in claim 6 wherein, The three-dimensional biomimetic curved surface structure is made of titanium alloy and has a three-dimensional porous structure with a Gyroid topology, and a plurality of microcolumnar protrusions are randomly distributed on the surface thereof.

8. The supercapacitor with high specific surface area as claimed in claim 7, wherein, The effective electrode surfaces of the two TC4@PANI electrodes are oppositely arranged and spaced at a distance.

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