Molybdenum oxide-molybdenum disulfide@polytannic acid electrode materials, their preparation methods and applications

Abstract

This invention belongs to the field of supercapacitor technology, specifically relating to a molybdenum oxide-molybdenum disulfide@polytannic acid electrode material, its preparation method, and its applications. Using molybdenum foil as the current collector and electrode, this invention prepares a molybdenum oxide-molybdenum disulfide electrode using electrochemical oxidation and hydrothermal methods. A polytannic acid coating is deposited on its surface to prepare a biodegradable molybdenum oxide-molybdenum disulfide@polytannic acid electrode. This electrode is then sandwiched with a biodegradable gel electrolyte and encapsulated with a biodegradable encapsulation material to construct a biodegradable supercapacitor with self-discharge suppression capabilities. By depositing a polytannic acid coating on the surface of the supercapacitor electrode, its self-discharge behavior is suppressed. The polytannic acid coating can prevent parasitic Faraday reactions of impurity ions on the electrode surface and prevent charge transfer, thereby suppressing the capacitor's self-discharge behavior. Simultaneously, the electrode, electrolyte, and encapsulation material can all degrade in simulated body fluids, potentially opening up applications in implantable medical electronic devices.

Description

Technical Field

[0001] This invention belongs to the field of supercapacitor technology, and specifically relates to a molybdenum oxide-molybdenum disulfide@polytannic acid electrode material, its preparation method, and its application. Background Technology

[0002] With the development of modern medical technology, implantable medical electronic devices (IMEs) have become an important component of the healthcare system. Because they can sense specific physicochemical parameters within the body and deliver electrical stimulation or drugs to target tissues or organs, they enable precise diagnosis and treatment of diseases. Typically, an IME consists of modules such as programming circuits, actuators, and a power supply device, with the power supply device being the core component driving the stable operation of the electronic device within the body.

[0003] Supercapacitors (SCs) hold promise for addressing the power needs of IMEs due to their high power density, long cycle life, and fast charge / discharge rates. However, the Gibbs free energy of SCs in the charging state is higher than in the discharging state, leading to severe self-discharge, voltage drop, current leakage, and capacity loss, thus affecting their normal operation. Furthermore, during implantation, the capacitor components (including electrodes, electrolyte, and encapsulation layer) may trigger inflammatory responses in the body, and they typically require a second surgery for removal after completing their biomedical function, placing an additional physical and financial burden on patients. Summary of the Invention

[0004] To address the above problems, in a first aspect, this invention proposes a method for preparing a molybdenum oxide-molybdenum disulfide@polytannic acid electrode material, characterized by comprising the following steps:

[0005] Molybdenum oxide nanosheets were grown on the surface of cleaned molybdenum foil using an anodic oxidation method.

[0006] Thiourea was added to a reaction vessel containing molybdenum oxide nanosheets to carry out a hydrothermal reaction, thereby preparing a molybdenum oxide-molybdenum disulfide electrode material.

[0007] The molybdenum oxide-molybdenum disulfide electrode material was placed in a tannic acid buffer solution and irradiated with ultraviolet light to deposit a polytannic acid coating on the surface of the electrode material, thus obtaining the molybdenum oxide-molybdenum disulfide@polytannic acid electrode material.

[0008] Furthermore, the method also includes ultrasonically cleaning the molybdenum foil sequentially with hydrochloric acid, acetone, anhydrous ethanol, and purified water;

[0009] The anodic oxidation method employs a three-electrode system with a voltage window of 0–0.8 V and a scan rate of 0.08–0.1 Vs. -1 The oxidation time is 4 to 10 minutes.

[0010] Furthermore, the specific conditions for the hydrothermal reaction are: hydrothermal reaction at 160~200℃ for 10~14 hours;

[0011] The concentration of the thiourea solution is 0.5~1.0M; specifically, the thiourea concentration can be 0.5M, 0.8M, or 1.0M, with 0.8M being the preferred concentration.

[0012] Furthermore, the buffer solution is a trihydroxymethylaminomethane hydrochloride buffer solution with a concentration of 5-20 mM; specifically, the concentration of the trihydroxymethylaminomethane hydrochloride buffer solution is 5, 10, or 20 mM, and the preferred Tris concentration is 10 mM.

[0013] The concentration of tannic acid in the buffer solution is 5~20 mg / mL; specifically, the concentration of tannic acid is 5, 10, or 20 mg / mL, and the preferred concentration of tannic acid is 10 mg / mL.

[0014] The wavelength of the ultraviolet light is 254~365nm, and the irradiation time is 0.5~5 hours. Specifically, the wavelength of the ultraviolet light is 254, 280, 310, or 365nm, and the irradiation time is 0.5, 1, 2, 3, or 5 hours. The preferred wavelength is 254nm, and the irradiation time is 2 hours.

[0015] Secondly, the present invention proposes a method for preparing a biodegradable molybdenum oxide-molybdenum disulfide@polytannic acid electrode material using the aforementioned preparation method.

[0016] Thirdly, the present invention proposes a method for suppressing the self-discharge behavior of a supercapacitor, using the aforementioned molybdenum oxide-molybdenum disulfide@polytannic acid electrode material as the electrode of the supercapacitor.

[0017] Fourthly, the present invention proposes a molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor, comprising a first electrode layer, a second electrode layer, and an electrolyte layer disposed between and in contact with the first electrode layer and the second electrode layer;

[0018] The first electrode layer and / or the second electrode layer are the molybdenum oxide-molybdenum disulfide@polytannic acid electrode material described above;

[0019] The electrolyte layer is a polyvinyl alcohol / sodium chloride gel electrolyte.

[0020] Fifthly, this invention proposes a method for preparing a molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor, comprising the following steps:

[0021] Polyvinyl alcohol was dissolved in sodium chloride solution at a concentration of 0.1~0.3 g / mL. After stirring, the solution was allowed to stand until it became transparent to obtain polyvinyl alcohol / sodium chloride gel electrolyte.

[0022] Polyvinyl alcohol / sodium chloride gel electrolyte is coated on the surface of the first electrode layer and the second electrode layer as described in claim 7, and the coated first electrode layer and the second electrode layer are bonded together to form a primary supercapacitor.

[0023] The polylactic acid-glycolic acid copolymer was mixed with chloroform at a ratio of 0.01~0.03:1 g / mL, dissolved by ultrasonication, and then coated onto the surface of the supercapacitor. The mixture was then left to stand under ventilation for 10~14 hours.

[0024] After ventilation, the supercapacitor is immersed in a liquid mixture of beeswax and candelilla wax, and then removed and naturally dried at room temperature to obtain an encapsulated molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor.

[0025] Furthermore, in the preparation process of polyvinyl alcohol / sodium chloride gel electrolyte:

[0026] The concentration of the sodium chloride solution is 0.5~2M;

[0027] The dissolution conditions for polyvinyl alcohol in sodium chloride solution are: stirring at room temperature for 20-40 minutes, then heating to 80-100℃ and stirring for 2-4 hours;

[0028] The settling conditions are 2~6℃ for 12~24 hours.

[0029] Furthermore, the ratio of the polylactic acid-glycolic acid copolymer to chloroform is 0.01~0.03:1 g / mL;

[0030] The mass ratio of beeswax to candelilla wax is 2-4:1;

[0031] The heating temperature of the beeswax and candelilla wax is 70~90℃.

[0032] The beneficial effects of this invention are:

[0033] This invention effectively suppresses the self-discharge behavior of supercapacitors by depositing a polytannic acid coating on the electrode surface. The polytannic acid coating reduces side reactions between the electrode and the electrolyte, slows down charge loss, and allows the supercapacitor to retain its charge for a longer period during storage. This significantly improves energy storage capacity, extends its effective operating time, and provides more reliable energy support for equipment that requires long standby or intermittent operation.

[0034] The molybdenum oxide-molybdenum disulfide@polytannic acid electrode material used in this invention, through an optimized preparation process, not only ensures the good conductivity and electrochemical activity of the electrode material, but also further improves the key performance indicators such as the cycle stability and specific capacitance of the electrode through the modification of the polytannic acid coating. This makes the supercapacitor's performance decay slowly during charge and discharge cycles and can work stably for a long time.

[0035] The supercapacitor prepared in this invention comprises biodegradable materials for all its components, including the electrode layer, electrolyte layer, and encapsulation material. The electrode layer material, molybdenum oxide-molybdenum disulfide@polytannic acid, is biodegradable. The biodegradable electrolyte layer uses PVA gel, and the encapsulation material employs biodegradable materials such as polylactic acid-glycolic acid copolymer (PLGA), beeswax, and candelilla wax. This avoids the environmental pollution problems caused by the disposal of traditional electronic devices, aligns with the trend of green environmental protection, reduces the generation of electronic waste, and is beneficial to ecological protection. Biodegradable materials can be gradually degraded into low-molecular-weight compounds or monomers through hydrolysis or enzymatic hydrolysis, and ultimately absorbed or excreted by the body through metabolism. On the one hand, biodegradable materials can avoid the side effects of secondary surgical removal; on the other hand, they can reduce the body's inflammatory response. Applying biodegradable materials to capacitors and inhibiting their self-discharge behavior is of great significance in promoting the further clinical application of IME (electrode electrocapacitor).

[0036] In terms of preparation and application, the relevant preparation methods are clear and easy to operate, the raw materials involved are readily available, and the preparation process does not use complex or highly polluting processes, making it suitable for large-scale production. Furthermore, the manufacturing method of this supercapacitor is simple, and the assembly and packaging processes are easy to control, ensuring product consistency and stability. Its excellent performance and biodegradable properties make it promising for applications in flexible electronic devices, biomedical implants, environmental monitoring equipment, and other fields, meeting the demand for high-performance, environmentally friendly energy storage devices in various scenarios.

[0037] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 Cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line comparisons, and electrochemical impedance spectroscopy (EIS) spectra of molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared with different tannic acid concentrations (5, 10, and 20 mg / mL) in Examples 1, 3, and 5 of this invention are shown. Wherein a) is the electrochemical impedance spectroscopy (EIS) spectrum of molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared with different tannic acid concentrations at 100 mV / s. -1 Comparison of CV values ​​at different scan rates, b) shows the molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared with different tannic acid concentrations at 0.5 mA cm⁻¹. -2 The GCD comparison diagrams at different current densities are as follows: c) is a comparison diagram of the specific capacitance results calculated based on the discharge time for molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared with different tannic acid concentrations; d) is a comparison diagram of the EIS of molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared with different tannic acid concentrations; e) and f) are comparison diagrams of molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared with a preferred tannic acid concentration of 10 mg / mL at current densities of 5, 10, 20, 30, 40, 50, and 100 mV s, respectively. -1 CV curves at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA / cm² -2 GCD curve at current density.

[0040] Figure 2 The images show the cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line comparisons, and self-discharge curves of the molybdenum oxide-molybdenum disulfide@polytannic acid capacitors (tannic acid concentrations of 5, 10, and 20 mg / mL) prepared in Examples 2, 4, and 6 of this invention. Specifically, a) shows the cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line comparisons, and self-discharge curves of the molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared with different tannic acid concentrations at 100 mV / s. -1 Comparison of CV curves at different scan rates, b) shows molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared with different tannic acid concentrations at 0.5 mA cm⁻¹. -2 Comparison of GCD curves under different current densities: c) is a line graph comparing the specific capacitance of molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared with different tannic acid concentrations, calculated based on discharge time; d) is a comparison of the self-discharge curves of molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared with different tannic acid concentrations; e) and f) are the GCD curves of molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared with a preferred tannic acid concentration of 10 mg / mL at current densities of 5, 10, 20, 30, 40, 50, 60, 80, and 100 mVs, respectively. -1 CV curves at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA / cm² -2 GCD curve at current density.

[0041] Figure 3Cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line graphs, and electrochemical impedance spectroscopy (EIS) spectra of molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared with different Tris concentrations (5, 10, and 20 mM) in Examples 3, 7, and 9 of this invention. Where a) represents 100 mV s. -1 Comparison of CV values ​​at different scan rates, b) is 0.5 mA cm⁻¹ -2 The GCD comparison diagrams at different current densities are shown in Figures 1-3. c) is a comparison diagram of the specific capacitance calculated based on the discharge time; d) is a comparison diagram of the EIS; and e) and f) are comparison diagrams of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared with the preferred Tris concentration of 10 mM at current densities of 5, 10, 20, 30, 40, 50, and 100 mV s. -1 CV curves at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA / cm² -2 GCD curve at current density.

[0042] Figure 4 Cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line graphs, and self-discharge curves are shown for molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared with different Tris concentrations (5, 10, and 20 mM) in Examples 4, 8, and 10 of this invention. Where a) represents 100 mV s. -1 Comparison of CV curves at different scan rates, b) is 0.5 mA cm⁻¹ -2 Comparison of GCD curves under current density: c) is a line graph comparing the specific capacitance calculated based on discharge time; d) is a comparison of the self-discharge curves of the capacitors; e) and f) are comparisons of molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared with a preferred Tris concentration of 10 mM at current densities of 5, 10, 20, 30, 40, 50, 60, 80, and 100 mV s, respectively. -1 CV curves at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA / cm² -2 GCD curve at current density.

[0043] Figure 5 Cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line graphs, and electrochemical impedance spectroscopy (EIS) spectra of molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared at different deposition times (0.5, 2, and 5 hours) in Examples 3, 11, and 13 of this invention. Where a) represents 100 mV s. -1 Comparison of CV curves at different scan rates, b) is 0.5 mA cm⁻¹ -2Comparison of GCD curves at current densities: c) is a comparison of specific capacitance results calculated based on discharge time; d) is an EIS comparison; e) and f) are comparisons of molybdenum oxide-molybdenum disulfide@polytannic acid electrodes prepared with an optimal deposition time of 2 hours at current densities of 5, 10, 20, 30, 40, 50, and 100 mV s. -1 CV plots at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA cm⁻¹ -2 GCD curve at current density.

[0044] Figure 6 The figures show the cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line graphs, and self-discharge curves of molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared at different deposition times in Examples 4, 12, and 14 of this invention. Where a) represents 100 mV s. -1 Comparison of CV curves at different scan rates, b) is 0.5 mA cm⁻¹ -2 Comparison of GCD curves under current density: c) is a line graph comparing the specific capacitance calculated based on discharge time; d) is a comparison of the self-discharge curves of the capacitor; e) and f) are the preferred molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared for 2 hours at 5, 10, 20, 30, 40, 50, 60, 80, and 100 mV s, respectively. -1 CV curves at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA / cm² -2 GCD curve at current density.

[0045] Figure 7 Cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line comparisons, and electrochemical impedance spectroscopy (EIS) spectra of molybdenum oxide electrodes prepared for different oxidation times (4, 6, and 10 minutes) in Comparative Examples 1-3 and the molybdenum oxide@polytannic acid electrode prepared in Comparative Example 5 are shown. Wherein a) represents the molybdenum oxide electrodes prepared for different oxidation times at 100 mV s⁻¹. -1 Comparison of CV curves at different scan rates, b) shows molybdenum oxide electrodes prepared at different oxidation times at 0.5 mA cm⁻¹. -2 Comparison of GCD curves at different current densities: c) is a line graph comparing the specific capacitance calculated from the discharge time for molybdenum oxide electrodes prepared at different oxidation times; d) is a comparison of EIS curves for molybdenum oxide electrodes prepared at different oxidation times; e) is a comparison of the EIS curves of the molybdenum oxide electrode prepared with a preferred oxidation time of 6 minutes and the electrode with polytannic acid deposited on the molybdenum oxide electrode selected in Comparative Example 3 at 100 mV s. -1 Comparison of CV curves at different scan rates, f) is 0.5 mA cm. -2 The comparison graphs of GCD curves under current density are shown in g), which is a comparison graph of the specific capacitance calculated based on the discharge time, and h) is a comparison graph of EIS.

[0046] Figure 8 The figures show the cyclic voltammetry (CV) curves, constant current charge-discharge (GCD) curves, specific capacitance line graphs, and self-discharge curves of the molybdenum oxide capacitor prepared in Comparative Example 4 and the molybdenum oxide@polytannic acid capacitor prepared in Comparative Example 6 of this invention. Where a) represents 100 mV / s. -1 Comparison of CV curves at different scan rates, b) is 0.5 mA cm⁻¹ -2 Comparison of GCD curves under current density: c) is a comparison of the specific capacitance calculated based on discharge time; d) is a comparison of the self-discharge curves of the capacitors; e) and f) are the preferred molybdenum oxide@polytannic acid capacitors at current densities of 5, 10, 20, 30, 40, 50, and 100 mV s. -1 CV curves at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA / cm² -2 GCD curve at current density.

[0047] Figure 9 The images show the cyclic voltammetry (CV) curves, galvanostatic charge-discharge (GCD) curves, specific capacitance line graphs, and electrochemical impedance spectroscopy (EIS) spectra of molybdenum oxide-molybdenum disulfide electrodes prepared with different thiourea concentrations (0.5, 0.8, 1.0 M) prepared in Comparative Examples 7-9 of this invention. Where a) represents 100 mV s. -1 Comparison of CV curves at different scan rates, b) is 0.5 mA cm⁻¹ -2 Comparison of GCD curves at current densities: c) is a comparison of specific capacitance results calculated based on discharge time; d) is an EIS comparison; e) and f) are comparisons of molybdenum oxide-molybdenum disulfide electrodes prepared with a preferred thiourea concentration of 0.8 M at current densities of 5, 10, 20, 30, 40, 50, and 100 mV s. -1 CV curves at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA / cm² -2 GCD curve at current density.

[0048] Figure 10 Cyclic voltammetry (CV) curves, constant current charge-discharge (GCD) curves, specific capacitance line graphs, and self-discharge curves are shown for the molybdenum oxide-molybdenum disulfide capacitor prepared in Comparative Example 10 and the molybdenum oxide-molybdenum disulfide@polytannic acid capacitor prepared in Example 4. Where a) represents 100 mV / s. -1 Comparison of CV curves at different scan rates, b) is 0.5 mA cm⁻¹ -2Comparison of GCD curves under current density: c) is a comparison of the specific capacitance calculated based on discharge time; d) is a comparison of the self-discharge curves of the capacitors; e) and f) are comparisons of the GCD curves of the preferred molybdenum oxide-molybdenum disulfide@polytannic acid capacitors at current densities of 5, 10, 20, 30, 40, 50, 60, 80, and 100 mV s, respectively. -1 CV curves at scan rates and at 0.5, 1, 2, 4, 6, and 8 mA / cm² -2 GCD curve at current density.

[0049] Figure 11A The molybdenum oxide-molybdenum disulfide@polytannic acid electrode is used at 3 mA cm⁻¹ -2 The curves after 20,000 cycles at current density are shown in the attached figure, which is a comparison of the GCD curves for the first three cycles and the last three cycles.

[0050] Figure 11B For molybdenum oxide-molybdenum disulfide@polytannic acid capacitors at 2mA cm -2 The graph shows the current density after 5000 cycles. The attached graph shows the LED light and timer after the capacitor is connected in series.

[0051] Figure 12A Optical images of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode sheet prepared in Example 4, which was immersed in 0.1M phosphate buffer (PBS) solution at 37°C for 15 weeks;

[0052] Figure 12B The graph shows the mass change of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode sheet prepared in Example 4 after immersion in 0.1M phosphate buffer (PBS) solution at 37°C for 15 weeks.

[0053] Figure 12C Optical images of the supercapacitor packaged in Example 15, immersed in 0.1M phosphate buffer (PBS) solution at 80°C for 6 weeks.

[0054] Figure 13 The images shown are scanning electron microscope (SEM) images (scale bar 5 μm) of the electrodes of Examples 3, Comparative Examples 1-3, and 8. Wherein a) is a blank molybdenum foil; b), c), and d) are molybdenum oxide electrodes of Comparative Examples 1-3 with oxidation times of 4, 6, and 10 minutes, respectively; e) is the preferred Comparative Example 8 molybdenum oxide-molybdenum disulfide electrode (thiourea concentration of 0.8 M); and f) is the SEM image of the preferred Example 3 molybdenum oxide-molybdenum disulfide@polytannic acid electrode (tannic acid concentration of 10 mg / mL, Tris concentration of 10 mM, deposition time of 2 hours).

[0055] Figure 14The images show scanning electron microscope (SEM) images of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode sheet prepared in Example 3 after degradation experiments over 1-9 weeks. a)~i) represent the microscopic changes on the electrode material surface from week 1 to week 9, respectively. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Example 1

[0058] Preparation of molybdenum oxide-molybdenum disulfide@polytannic acid electrode.

[0059] 1) Sonicate the molybdenum foil with dilute hydrochloric acid solution for 30 minutes to remove impurities such as oxides on the surface of the molybdenum foil, then sonicate wash with acetone, ethanol and purified water for 10 minutes respectively, and dry at 60°C to obtain clean molybdenum foil.

[0060] 2) Using cleaned molybdenum foil as a substrate, molybdenum oxide nanosheets were grown on its surface via anodic oxidation using an electrochemical workstation. Specifically, the molybdenum foil was used as the working electrode, a platinum (Pt) sheet as the counter electrode, and silver / silver chloride (Ag / AgCl) as the reference electrode. A constant voltage of 0–0.8 V was applied to the molybdenum foil in a 1 M NaCl electrolyte for 6 minutes. During anodic oxidation, the distance between the Pt sheet and the molybdenum foil remained constant. After oxidation, the oxidized molybdenum foil was carefully rinsed with purified water and dried under vacuum for 30 minutes to prepare the molybdenum oxide electrode.

[0061] 3) The prepared molybdenum oxide electrode was transferred to a 50 mL high-pressure reactor lined with polytetrafluoroethylene, and 30 mL of 0.8 M thiourea was added. The hydrothermal reaction was carried out at 180 °C for 12 hours to prepare a molybdenum oxide-molybdenum disulfide electrode.

[0062] 4) Take 50 mg of tannic acid and add it to 10 mL of 10 mM Tris-hydroxymethylaminomethane hydrochloride (Tris) buffer solution to prepare a tannic acid solution with a concentration of 5 mg / mL. Place the molybdenum oxide-molybdenum disulfide electrode at the bottom of a glass culture dish and use a UV analyzer at a wavelength of 254 nm. After crosslinking for 2 hours, the molybdenum oxide-molybdenum disulfide@polytannic acid electrode is prepared.

[0063] Example 2

[0064] Dissolve 2g of polyvinyl alcohol (PVA) gel in 10mL of sodium chloride (NaCl) solution (1M). Stir slowly at room temperature for 30 minutes to allow the PVA to swell fully. Then gradually raise the temperature to 90℃ and stir for 3 hours. Once the solution becomes transparent, pour the homogeneous solution into a glass dish and let it stand overnight at 4℃ to obtain the PVA / NaCl gel electrolyte.

[0065] PVA / NaCl gel electrolyte was coated onto the surface of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared in Example 1. The molybdenum oxide-molybdenum disulfide@polytannic acid electrode was used as the first electrode layer and the second electrode layer. The two coated electrode layers were glued together and assembled into a whole with a sandwich-like structure to prepare a molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor.

[0066] Example 3

[0067] The molybdenum oxide-molybdenum disulfide@polytannic acid electrode was prepared using the same method as in Example 1, except that the concentration of tannic acid was 10 mg / mL.

[0068] Example 4

[0069] The biodegradable supercapacitor was constructed in the same manner as in Example 2, except that the first and second electrode layers used the molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared in Example 3 (tannic acid concentration of 10 mg / mL).

[0070] Example 5

[0071] The molybdenum oxide-molybdenum disulfide@polytannic acid electrode was prepared using the same method as in Example 1, except that the concentration of tannic acid was 20 mg / mL.

[0072] Example 6

[0073] The biodegradable supercapacitor was constructed in the same manner as in Example 2, except that the first and second electrode layers used the molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared in Example 5 (tannic acid concentration of 20 mg / mL).

[0074] Example 7

[0075] The molybdenum oxide-molybdenum disulfide@polytannic acid electrode was prepared using the same method as in Example 1, except that the Tris concentration was 5 mM.

[0076] Example 8

[0077] The biodegradable supercapacitor was constructed in the same manner as in Example 2, except that the first and second electrode layers used the molybdenum oxide-molybdenum disulfide@polytannic acid electrode (Tris concentration of 5mM) prepared in Example 7.

[0078] Example 9

[0079] The molybdenum oxide-molybdenum disulfide@polytannic acid electrode was prepared using the same method as in Example 1, except that the Tris concentration was 20 mM.

[0080] Example 10

[0081] The biodegradable supercapacitor was constructed in the same manner as in Example 2, except that the first and second electrode layers used the molybdenum oxide-molybdenum disulfide@polytannic acid electrode (Tris concentration of 20 mM) prepared in Example 9.

[0082] Example 11

[0083] The molybdenum oxide-molybdenum disulfide@polytannic acid electrode was prepared using the same method as in Example 1, except that it was cross-linked and deposited using a UV analyzer for 0.5 hours.

[0084] Example 12

[0085] The biodegradable supercapacitor was constructed in the same manner as in Example 2, except that the first and second electrode layers used the molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared in Example 11 (crosslinked deposition using a UV analyzer for 0.5 hours).

[0086] Example 13

[0087] The molybdenum oxide-molybdenum disulfide@polytannic acid electrode was prepared using the same method as in Example 1, except that it was cross-linked and deposited using a UV analyzer for 5 hours.

[0088] Example 14

[0089] The biodegradable supercapacitor was constructed in the same manner as in Example 2, except that the first and second electrode layers used the molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared in Example 11 (crosslinked deposition using a UV analyzer for 5 hours).

[0090] Example 15

[0091] Encapsulation of a biodegradable supercapacitor with self-discharge suppression function.

[0092] (1) Prepare molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitors in the same manner as in Example 4.

[0093] (2) After coating and sealing the edge of the supercapacitor with 1 mL of PVA gel, let it solidify for 3 hours; separately weigh 0.1 g of polylactic acid-hydroxyacetic acid copolymer (PLGA) and add 6 mL of chloroform, sonicate to dissolve and coat it on the surface of the supercapacitor, and place it in a fume hood for 12 hours; finally weigh 12 g of beeswax and 4 g of candelilla wax, heat and stir at 80 °C, melt it and immerse the supercapacitor in it, take it out and let it dry naturally at room temperature to prepare the wax-sealed molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor.

[0094] Comparative Example 1

[0095] Preparation of molybdenum oxide electrode: Molybdenum oxide electrode was prepared according to steps 1) and 2) in Example 1 (anodic oxidation treatment time was 6 minutes).

[0096] Comparative Example 2

[0097] Following steps 1) and 2) in Example 1, a molybdenum oxide electrode was prepared, except that the anodic oxidation treatment time was 4 minutes.

[0098] Comparative Example 3

[0099] Following steps 1) and 2) in Example 1, a molybdenum oxide electrode was prepared, except that the anodic oxidation treatment time was 10 minutes.

[0100] Comparative Example 4

[0101] Construction of a molybdenum oxide supercapacitor. A molybdenum oxide supercapacitor was constructed using the same method as in Example 2, except that the first and second electrode layers used were the molybdenum oxide electrodes prepared in Comparative Example 1 (anodic oxidation treatment time was 6 minutes).

[0102] Comparative Example 5

[0103] Preparation of molybdenum oxide@polytannic acid electrode. The molybdenum oxide electrode prepared in Comparative Example 1 was placed in a solution containing 10 mg / mL... -1 Molybdenum oxide@polytannic acid electrode was prepared by crosslinking molybdenum oxide in a Tris buffer solution (10 mM) of tannic acid for 2 hours using a UV analyzer.

[0104] Comparative Example 6

[0105] Construction of a molybdenum oxide@polytannic acid supercapacitor. A molybdenum oxide@polytannic acid supercapacitor was constructed using the same method as in Example 2, except that the first and second electrode layers used were the molybdenum oxide@polytannic acid electrodes prepared in Comparative Example 5.

[0106] Comparative Example 7

[0107] Preparation of molybdenum oxide-molybdenum disulfide electrode. The molybdenum oxide-molybdenum disulfide electrode (thiourea concentration of 0.8M) was prepared according to the same steps as 1), 2), and 3) in Example 1.

[0108] Comparative Example 8

[0109] Preparation of molybdenum oxide-molybdenum disulfide electrode. The molybdenum oxide-molybdenum disulfide electrode was prepared according to the same steps as 1), 2), and 3) in Example 1, except that the thiourea concentration was 0.5M.

[0110] Comparative Example 9

[0111] The molybdenum oxide-molybdenum disulfide electrode was prepared using the same steps as in Example 1 (1), (2), and (3), except that the thiourea concentration was 1.0 M.

[0112] Comparative Example 10

[0113] Construction of a molybdenum oxide-molybdenum disulfide supercapacitor. A molybdenum oxide-molybdenum disulfide supercapacitor was constructed according to the same method as in Example 2, except that the first and second electrode layers used were the molybdenum oxide-molybdenum disulfide electrodes prepared in Comparative Example 7 (thiourea concentration of 0.8M).

[0114] Test Example 1

[0115] Electrochemical performance tests were performed on the electrodes and supercapacitors prepared in Examples 1-14 and Comparative Examples 1-10 of the present invention, including cyclic voltammetry, constant current charge-discharge test, electrochemical impedance spectroscopy, and self-discharge test.

[0116] 1) Cyclic voltammetry (CV) testing: Using a CHI660E electrochemical workstation, in a three-electrode system, the electrodes prepared in Examples 1, 3, 5, 7, 9, 11, 13 and Comparative Examples 1-3, 5, 7-9 were used as working electrodes, a platinum sheet electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Cyclic voltammetry was performed at 5, 10, 20, 30, 40, 50, and 100 mVs within a voltage range of -0.8 to 0 V. -1 The CV curves of the electrodes were obtained by testing at different scan rates.

[0117] Test results are as follows Figure 1 a) and e) Figure 3 a) and e) Figure 5 a) and e) Figure 7 a) and e) Figure 9 As shown in a) and e).

[0118] In a two-electrode system, the supercapacitors prepared in Examples 2, 4, 6, 8, 10, 12, 14 and Comparative Examples 4, 6, 10 exhibit voltage ranges of 0~1.5V and 5, 10, 20, 30, 40, 50, 60, 80, and 100 mVs. -1 The CV curves of the capacitor were obtained by testing at different scan rates. The test results are as follows: Figure 2 a) and e) Figure 4 a) and e) Figure 6 a) and e) Figure 8 a) and e) Figure 10 As shown in a) and e), the CV curves are nearly rectangular, exhibiting pseudocapacitive characteristics, and the electrochemical reaction is highly reversible. Compared to the molybdenum oxide electrode (Comparative Example 5 and Comparative Example 1) and the molybdenum oxide-molybdenum disulfide@polytannic acid electrode (Example 3 and Comparative Example 7), the area of ​​the CV curve of the molybdenum oxide@polytannic acid electrode after tannic acid deposition is increased, reflecting enhanced charge storage capacity. At the same scan rate, the preferred Example 3 molybdenum oxide-molybdenum disulfide@polytannic acid (tannic acid concentration 10 mg / mL, Tris concentration 10 mM, deposition time 2 hours) electrode and Example 4 capacitor have the largest closed area of ​​the CV curve, indicating that the electrode prepared in Example 3 and the capacitor in Example 4 have stronger charge storage capacity; and at different scan rates (e.g., ... Figure 1 (e) Figure 2 (e) Figure 3 (e) Figure 4 (e) Figure 5 (e) Figure 6 (e) The closed area increases with increasing scan rate, and the shape of the curve hardly changes, indicating that the prepared electrode and capacitor have high reversibility during the insertion and extraction of electrolyte ions.

[0119] 2) Galvanostatic charge-discharge (GCD) test: In a three-electrode system, using a CHI660E electrochemical workstation, the current densities were 0.5, 1, 2, 4, 6, and 8 mA cm⁻¹ within a voltage range of -0.8 to 0 V. -2 The electrodes prepared in Examples 1, 3, 5, 7, 9, 11, 13 and Comparative Examples 1-3, 5, 7-9 were subjected to GCD testing, and the test results are as follows. Figure 1 b) and f), Figure 3 b) and f), Figure 5 b) and f), Figure 7 b) and f), Figure 9 As shown in b) and f), the GCD curves are triangular in shape and basically symmetrical from left to right. The surface electrode charging and discharging process is highly reversible and exhibits pseudocapacitive characteristics. The specific capacitance of each electrode is calculated based on the GCD curves.

[0120] At 0.5mA cm -2 At the given current density, the specific capacitance values ​​calculated based on the discharge time for Examples 1, 3, 5, 7, 9, 11, 13 and Comparative Examples 1, 2, 3, 5, 7, 8, 9 were 162.38, 227.75, 202.81, 157.12, 183.75, 148.25, 189.68, 52.50, 18.00, 52.00, 66.18, 177.50, 148.56, and 146.68 mF / cm², respectively. -2 ( Figure 1 c) Figure 3 c) Figure 5 c) Figure 7 c) and g) Figure 9 In Example 3 (tannic acid concentration of 10 mg / mL, Tris concentration of 10 mM, deposition time of 2 hours), the electrode discharge time was the longest at 364.4 s and the specific capacitance was the highest at 227.75 mF cm⁻¹. -2 .

[0121] In the two-electrode system, the supercapacitors prepared in Examples 2, 4, 6, 8, 10, 12, 14 and Comparative Examples 4, 6, 10 all had a voltage window of 0~1.5V, and the current densities were 0.5, 1, 2, 4, 6, 8 mA cm⁻¹. -2 The charging and discharging performance was evaluated, and the results are as follows: Figure 2 b) and f), Figure 4 b) and f), Figure 6 b) and f), Figure 8 b) and f), Figure 10 As shown in b) and f), the GCD curves exhibit a triangular shape, are basically symmetrical, and demonstrate high reversibility of the surface electrode charging and discharging process, exhibiting pseudocapacitive characteristics. The specific capacitance curves of each capacitor calculated based on the GCD curves (at 0.5 mA cm⁻¹) are also provided. -2 At the given current density, the specific capacitance values ​​calculated based on the discharge time for Examples 2, 4, 6, 8, 10, 12, and 14, and Comparative Examples 4, 6, and 10, were 76.53, 90.00, 82.80, 57.00, 81.00, 56.33, 71.76, 25.45, 34.58, and 53.13 mF / cm, respectively. -2 ( Figure 2 c) Figure 4 c) Figure 6 c) Figure 8 c) Figure 10 (c) Among them, the capacitor prepared in Example 4 had the longest GCD discharge time of 257s and the highest specific capacitance of 90mF cm. -2 .

[0122] The stability of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared in Example 3 and the supercapacitor prepared in Example 4 were evaluated, and the results are as follows: Figure 11A and Figure 11B As shown, the molybdenum oxide-molybdenum disulfide@polytannic acid electrode still retains 80.68% of its capacitance after 20,000 cycles, and the molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor still retains 81.09% of its capacitance after 5,000 cycles. This capacitor can light up an LED and drive a timer.

[0123] 3) Electrochemical impedance spectroscopy (EIS) test: at a frequency range of 10 -2 -10 5 EIS tests were performed on the electrodes prepared in Examples 1, 3, 5, 7, 9, 11, 13 and Comparative Examples 1-3, 5, 7-9 at a voltage of 5mV and a frequency of Hz. The results are as follows: Figure 1 d) Figure 3 d) Figure 5 d) Figure 7 d) and h) Figure 9 As shown in d), the equivalent series resistance (Rs) related to electrolyte resistance, intrinsic resistance and interfacial contact resistance can be represented by the real intercept. The molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared in Example 3 has the smallest Rs of 3.72Ω, indicating that it has the best conductivity.

[0124] 4) Self-discharge test: The open-circuit voltage measurement method (OCP) was used to evaluate the self-discharge resistance of the device. The supercapacitor was charged to 1.5V, and the voltage decay of the device over 12 hours was observed. The self-discharge test results of Examples 2, 4, 6, 8, 10, 12, 14 and Comparative Examples 4, 6, 10 are as follows: Figure 2 d) Figure 4 d) Figure 6 d) Figure 8 d) Figure 10 As shown in d), the molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor prepared in the preferred embodiment 4 has a self-discharge rate of 76.17 mV / h. -1 All of these values ​​are lower than the self-discharge rate of 103.91 mV / h of the molybdenum oxide-molybdenum disulfide@polytannic acid capacitors prepared in Examples 2, 6, 8, 10, 12, and 14. -1 81.58mV h -1 90.67mV h -1 85.25mV h -1 106.25mV h -199.83mV h -1 Furthermore, it is significantly lower than the self-discharge rate of 112.33 mV / h of the molybdenum oxide-molybdenum disulfide capacitor without tannic acid deposition (Comparative Example 8). -1 Additionally, in Comparative Example 6, a molybdenum oxide@polytannic acid capacitor with deposited tannic acid (63.82 mV h) -1 It was also lower than that of the molybdenum oxide capacitor without tannic acid deposition in Comparative Example 4 (91.38 mV h). -1 The self-discharge rate of the capacitor indicates that the polytannic acid coating can hinder the parasitic Faraday reaction of impurity ions on the electrode surface and prevent charge transfer, thereby reducing the self-discharge rate of the capacitor and demonstrating good anti-self-discharge performance.

[0125] Test Example 2

[0126] Electrode and capacitor degradation performance testing:

[0127] Electrode degradation experiment: The molybdenum oxide-molybdenum disulfide@polytannic acid electrode sheet prepared in Example 3 was immersed in a 0.1M phosphate buffer (PBS) solution simulating a body fluid environment (PBS solution preparation: 80g NaCl, 2g KCl, 15.4g Na2HPO4·12H2O and 0.20g KH2PO4 were dissolved in 1L purified water under stirring at room temperature), and kept in a 37℃ water bath. The degradation process was recorded by taking optical images and weighing the changes in mass. Figure 12A Optical images of the degradation process of molybdenum oxide-molybdenum disulfide@polytannic acid electrode sheet over 15 weeks. As time goes on, the material gradually cracks and finally the degradation is basically completed by 15 weeks. Figure 12B The graph shows the mass change of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode sheet during the degradation process over 15 weeks. The results are consistent with those observed in macroscopic photographs. As time goes by, the mass of the electrode gradually decreases and approaches 0 after 15 weeks, indicating that the electrode material can be degraded and metabolized in a simulated human body fluid environment.

[0128] Capacitor degradation experiment: The supercapacitor encapsulated in Example 15 was immersed in PBS solution at 80°C, and the degradation process of the supercapacitor with the encapsulation wax layer was observed. Figure 12C Optical images of the assembled supercapacitor after immersion in 0.1M phosphate-buffered saline (PBS) solution at 80°C for 6 weeks. As can be seen from the images, the PLGA layer and wax layer on the outside of the device gradually degrade after 12 hours, while the encapsulated capacitor degrades relatively completely after 6 weeks.

[0129] Test Example 3

[0130] Characterization of the apparent morphology of electrode materials:

[0131] The morphology of the fabricated electrode material was characterized using scanning electron microscopy (SEM), such as... Figure 13 As shown, where Figure 13 In Figure a), blank molybdenum foil material has a smooth and flat surface. Figure 13 Examples b), c), and d) represent comparative examples 1-3, i.e., molybdenum oxide materials obtained by oxidation for 4, 6, and 10 minutes, respectively. Compared with the smooth morphology of the molybdenum foil surface, the oxidized molybdenum foil surface has a cracked layer, indicating that a molybdenum oxide layer has formed on the surface of the molybdenum foil. Figure 13 In Figure e), molybdenum oxide-molybdenum disulfide material is used as comparative example 7. Compared with molybdenum oxide electrode material in comparative example 1, its surface exhibits a nanosheet structure, and the surface sulfidation reaction successfully grows molybdenum disulfide nanosheets on the surface of molybdenum oxide. Figure 13 (f) is the molybdenum oxide-molybdenum disulfide@polytannic acid material of Example 3. Compared with the above molybdenum oxide-molybdenum disulfide material, the tannic acid coating structure can be clearly observed on the surface.

[0132] The morphology of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode prepared in Example 3 was characterized during degradation. Scanning electron microscopy (SEM) images are shown below. Figure 14 As shown. Among them. Figure 14 In Figures a) to i), the SEM images of the electrode after degradation experiments from week 1 to week 9 are shown. It can be seen that the material degrades and detaches layer by layer over time, which is consistent with the results observed in macroscopic optical images.

[0133] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a molybdenum oxide-molybdenum disulfide@polytannin electrode material, characterized in that, Includes the following steps: Molybdenum oxide nanosheets were grown on the surface of cleaned molybdenum foil using an anodic oxidation method. Thiourea was added to a reaction vessel containing molybdenum oxide nanosheets to carry out a hydrothermal reaction, thereby preparing a molybdenum oxide-molybdenum disulfide electrode material. The molybdenum oxide-molybdenum disulfide electrode material was placed in a tannic acid buffer solution and irradiated with ultraviolet light to deposit a polytannic acid coating on the surface of the electrode material, thus obtaining the molybdenum oxide-molybdenum disulfide@polytannic acid electrode material.

2. The preparation method of the molybdenum oxide-molybdenum disulfide@polytannic acid electrode material according to claim 1, characterized in that, The method also includes ultrasonic cleaning of the molybdenum foil sequentially with hydrochloric acid, acetone, anhydrous ethanol and purified water. The anodic oxidation method adopts a three-electrode system, the voltage window is 0~0.8V, the scanning rate is 0.08~0.1Vs -1 , and the oxidation time is 4~10 minutes.

3. The method for preparing the molybdenum oxide-molybdenum disulfide@polytannic acid electrode material according to claim 1, characterized in that, The specific conditions for the hydrothermal reaction are: hydrothermal reaction at 160~200℃ for 10~14 hours; The concentration of thiourea is 0.5~1.0M.

4. The method for preparing the molybdenum oxide-molybdenum disulfide@polytannic acid electrode material according to claim 1, characterized in that, The buffer solution is a trihydroxymethylaminomethane hydrochloride buffer solution with a concentration of 5-20 mM; The concentration of tannic acid in the buffer solution is 5~20 mg / mL; The wavelength of the ultraviolet light is 254~365nm, and the irradiation time is 0.5~5 hours.

5. A molybdenum oxide-molybdenum disulfide@polytannic acid electrode material, characterized in that, It is prepared by the preparation method according to any one of claims 1-4.

6. A method for suppressing the self-discharge behavior of a supercapacitor, characterized in that, The molybdenum oxide-molybdenum disulfide@polytannic acid electrode material described in claim 5 is used as the electrode of the supercapacitor.

7. A molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor, characterized in that, It includes a first electrode layer, a second electrode layer, and an electrolyte layer disposed between and in contact with the first electrode layer and the second electrode layer; The first electrode layer and / or the second electrode layer is the molybdenum oxide-molybdenum disulfide@polytannic acid electrode material as described in claim 5; The electrolyte layer is a polyvinyl alcohol / sodium chloride gel electrolyte.

8. A method for preparing a molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor as described in claim 7, characterized in that, Includes the following steps: Polyvinyl alcohol was dissolved in sodium chloride solution at a concentration of 0.1~0.3 g / mL. After stirring, the solution was allowed to stand until it became transparent to obtain polyvinyl alcohol / sodium chloride gel electrolyte. A supercapacitor is formed by coating the surfaces of the first and second electrode layers with a polyvinyl alcohol / sodium chloride gel electrolyte and then bonding the coated first and second electrode layers together. The polylactic acid-glycolic acid copolymer was mixed with chloroform at a ratio of 0.01~0.03:1 g / mL, dissolved by ultrasonication, and then coated onto the surface of the supercapacitor. The mixture was then left to stand under ventilation for 10~14 hours. After ventilation, the supercapacitor is immersed in a liquid mixture of beeswax and candelilla wax, and then removed and naturally dried at room temperature to obtain an encapsulated molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor.

9. The method for preparing the molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor according to claim 8, characterized in that, In the preparation process of polyvinyl alcohol / sodium chloride gel electrolyte: The concentration of the sodium chloride solution is 0.5~2M; The dissolution conditions for polyvinyl alcohol in sodium chloride solution are: stirring at room temperature for 20-40 minutes, then heating to 80-100℃ and stirring for 2-4 hours; The settling conditions are 2~6℃ for 12~24 hours.

10. The method for preparing the molybdenum oxide-molybdenum disulfide@polytannic acid supercapacitor according to claim 8, characterized in that, The ratio of polylactic acid-glycolic acid copolymer to chloroform is 0.01~0.03:1 g / mL; The mass ratio of beeswax to candelilla wax is 2-4:1; The heating temperature of the beeswax and candelilla wax is 70~90℃.

Images