Photo-assisted rechargeable lithium ion battery based on Schottky heterostructure positive electrode and preparation method of photo-assisted rechargeable lithium ion battery

Abstract

The invention belongs to the technical field of energy materials, and discloses a photo-assisted rechargeable lithium ion battery based on a Schottky heterostructure positive electrode, the photo-assisted rechargeable lithium ion battery comprises a lithium negative electrode, a solid electrolyte, a Schottky heterostructure photo-assisted positive electrode and FTO conductive glass with a transparent substrate, and a titanium dioxide semiconductor material and metal gold are compounded to serve as the battery positive electrode. On one hand, gold is nanoparticles, a plasma effect exists, and the light absorption capacity is remarkably improved, on the other hand, a built-in electric field is generated at a phase interface, the material has a lower ion migration energy barrier in the electrochemical process, and the ion diffusion capacity is higher and faster; the positive electrode material not only can collect solar energy similar to a solar cell, but also can store solar energy like energy storage equipment, so that the complexity and energy loss of a solar system are reduced; meanwhile, through the plasma effect, surface plasma resonance is shown, the optical path is increased, and a built-in electric field of the heterostructure achieves effective separation of photo-induced electrons and holes, so that the battery interface resistance is effectively reduced, the conductivity of an electrode material is increased, and the battery capacity is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy materials, and in particular relates to a light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode and a preparation method thereof. Background Art

[0002] Exploring alternative renewable energy sources is an effective and feasible way to meet the growing demand for energy. Solar energy is recognized as an efficient and economical alternative energy source for its advantages such as being green, low-cost, and abundant in supply. However, solar energy is an intermittent energy source, and the intensity of light is greatly affected by region, season, and climate, making it impossible to use it as a stable energy supply. The combination of solar cells and batteries is used in a variety of applications from large solar power plants to small autonomous sensing devices. Research has been conducted on the integration of solar cells and energy storage systems, and remarkable achievements have been made in the integration of solar cells and batteries. However, this technology usually requires additional electronic devices to match the required solar cell output and battery or capacitor input, which increases ohmic contact losses and also increases the complexity of the device. Summary of the Invention

[0003] To solve the above problems, the present invention discloses a light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode and a preparation method thereof. The positive electrode of the battery is composed of semiconductor titanium dioxide with a heterostructure and gold nanoparticles. On the one hand, the gold is in nanoparticle form and has a plasma effect, which significantly improves the light absorption capacity. On the other hand, a built-in electric field is generated at the phase interface. The material itself has a lower ion migration energy barrier during the electrochemical process and a stronger and faster ion diffusion capacity. This positive electrode material can both collect solar energy similar to a solar cell and store solar energy like an energy storage device, reducing the complexity and energy loss of the solar energy system. At the same time, through the plasma effect, surface plasmon resonance is exhibited, which increases the optical path. The built-in electric field of the heterostructure achieves effective separation of photogenerated electrons and holes, effectively reducing the battery interface resistance and increasing the conductivity of the electrode material, thereby improving the battery capacity.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] The present invention provides a light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode, which is mainly composed of a lithium negative electrode, a solid electrolyte, a Schottky heterostructure light-assisted positive electrode, and FTO conductive glass with a transparent substrate. The Schottky heterostructure light-assisted positive electrode is composed of titanium dioxide and gold nanoparticles.

[0006] Furthermore, the solid electrolyte is amorphous lithium phosphorus oxygen nitrogen (LIPON), that is, nitrogen-doped lithium phosphate; and the light-assisted rechargeable lithium-ion battery is an all-solid-state thin-film battery.

[0007] Furthermore, the preparation method of the Schottky heterostructure light-assisted positive electrode includes the following steps:

[0008] S1-1. Cut the purchased FTO etching glass substrate into the required size. Clean the glass substrate to remove organic and inorganic impurities on the surface and reduce the possibility of impurity contamination of the film during the preparation process. After the substrate is cleaned, store it in ethanol.

[0009] S1-2. Take out the glass substrate and dry it in a drying oven. After drying, place the substrate in a gold spraying apparatus for gold plating.

[0010] S1-3. Cover the gold-plated FTO glass substrate with a mold, fix it on the substrate tray, and place it in the sputtering position in the magnetron sputtering chamber. Use a titanium target to perform radio frequency controlled sputtering in an argon oxygen environment to deposit a titanium dioxide film on the substrate. The obtained product is the Schottky heterostructure light-assisted positive electrode.

[0011] Furthermore, in step S1-1, the cleaning was performed using a detergent, ultrasonic cleaning with anhydrous ethanol for 3 times, and ultrasonic cleaning with deionized water for 3 times, and then placed in an ultrasonic machine for cleaning for 10 minutes.

[0012] Furthermore, in step S1-2, the chamber of the spray metallurgical instrument is evacuated to below 0.5 Pa, the time is set to 10-40 seconds, and the current is 10 mA.

[0013] As a preferred embodiment of the present invention, the gold spraying time is incremented every 10 seconds.

[0014] Furthermore, in step S1-3, the sputtering chamber vacuum chamber is evacuated to 1.0×10 -5 Pa below, call the sputtering program, start sputtering, introduce gas, adjust the gas flow to 60 sccm (Ar:O2=50:10), set the sputtering power to 80 W. Pre-sputtering time is 1 minute (to remove impurities on the target surface), open the target head cover, and set the sputtering coating time in the program to 28800 seconds.

[0015] The present invention also provides a method for preparing a light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode, comprising the following steps:

[0016] S2-1. Cover the reserved tabs of the deposited Schottky heterostructure light-assisted positive electrode substrate with a mold, fix the substrate on a tray, and place it in the chamber of the magnetron sputtering device. The electrolyte uses a lithium phosphate target and is deposited on the positive electrode titanium dioxide film under a nitrogen environment at room temperature to obtain a LIPON inorganic solid electrolyte;

[0017] S2-2, taking out the substrate after the electrolyte film is sputtered, placing it on the evaporation substrate table, and plating lithium by thermal evaporation under a vacuum environment. The battery finally taken out is the light-assisted rechargeable lithium-ion battery;

[0018] Wherein, the Schottky heterostructure light-assisted positive electrode in step S2-1 is the Schottky heterostructure light-assisted positive electrode according to any one of claims 3-6.

[0019] Furthermore, in step S2-1, the vacuum chamber is evacuated to 1.0×10 -5 Below Pa, call the RF sputtering program, introduce nitrogen, control the air flow rate to 90sccm, set the power to 100W, pre-sputtering time to 1min, open the target head cover, and set the sputtering coating time in the program to 36000s.

[0020] Furthermore, in step S2-2, the vacuum chamber is evacuated to 1.0×10 -5 Pa below, call the program, set the crucible temperature to rise, and start evaporating metallic lithium. According to the deposition rate reading obtained by the quartz crystal sensor, the deposition rate is controlled at 4-6nm s -1 , the deposition thickness of the film is controlled at 2.5μm.

[0021] The light source used for light assistance in actual testing includes but is not limited to one or more of xenon lamps, LED lamps, and UV lamps, with a light intensity of 10-300mW / cm 2 .

[0022] The beneficial effects of the present invention are:

[0023] (1) The light-assisted rechargeable lithium-ion battery of the present invention uses a Schottky heterostructure material composed of titanium dioxide and gold nanoparticles as the positive electrode. The presence of the heterostructure generates a built-in electric field at the interface. Thanks to the presence of the built-in electric field, the material itself has a lower ion migration energy barrier in the electrochemical process, and the ion diffusion ability is stronger and faster. Figure 11 and Figure 12 Comparison shown.

[0024] (2) When a certain wavelength of light irradiates the material, a large number of electron-hole pairs will be generated, and the electrons will be transferred to the negative electrode to form a photocurrent. The light energy is converted into electrical energy, and the electrical energy is converted into chemical energy, realizing a light-assisted rechargeable lithium-ion battery. Under light, the charging voltage can be reduced, effectively reducing the energy consumed by charging, while also increasing the capacity of the battery. Figure 8 shown.

[0025] (3) Due to the existence of the built-in electric field in the heterostructure, the recombination of photogenerated electrons and holes is significantly inhibited. Compared with a single photocatalytic material, this design allows more photogenerated electrons and holes to participate in the electrochemical reaction. At the same time, the metal gold is in the form of nanoparticles, such as Figure 2 As shown in Figure 2, there is a plasma enhancement effect, which shows surface plasma resonance, increases the optical path, and enhances the light absorption in the positive electrode, thereby promoting the rapid transmission of electrons and ions inside the positive electrode and the charge transfer at the electrode / electrolyte interface. Figure 13 As shown in the attached figure, the efficiency of the positive electrode is improved, and the capacity of the battery is further increased. Figure 5 and Figure 8 shown.

[0026] In summary, the light-assisted charging all-solid-state thin-film lithium-ion battery of the present invention has a simple structure, is environmentally friendly, low cost and highly safe, and realizes the effective combination and efficient utilization of solar energy and energy storage systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 X-ray diffraction (XRD) patterns of the Schottky heterostructure positive electrode and the pure titanium dioxide positive electrode in Examples 2, 3, 4 and Comparative Example 1;

[0028] Figure 2 This is an atomic force microscope (AFM) scan of the Schottky heterostructure light-assisted positive electrode in Example 3;

[0029] Figure 3 This is a scanning electron microscope (TEM) image of the titanium dioxide thin film positive electrode material in Comparative Example 1;

[0030] Figure 4 It is a light response graph of the titanium dioxide thin film cathode material in Comparative Example 1;

[0031] Figure 5 This is a comparison chart of constant current charge and discharge curves of the Schottky heterostructure light-assisted positive electrode in Examples 1, 2, 3, and 4 and the pure titanium dioxide light-assisted positive electrode in Comparative Example 1;

[0032] Figure 6 Comparison of cyclic voltammograms of the Schottky heterostructure light-assisted positive electrode in Examples 1, 2, 3, and 4 and the pure titanium dioxide light-assisted positive electrode in Comparative Example 1;

[0033] Figure 7 Comparison of rate performance curves of the Schottky heterostructure light-assisted positive electrode in Examples 1, 2, 3, and 4 and the pure titanium dioxide light-assisted positive electrode in Comparative Example 1;

[0034] Figure 8This is a comparison of constant current charge and discharge curves of the Schottky heterostructure light-assisted positive electrode in Example 3 and the pure titanium dioxide light-assisted positive electrode in Comparative Example 1 before and after illumination;

[0035] Figure 9 This is a comparison of the cyclic voltammograms of the Schottky heterostructure light-assisted positive electrode in Example 3 and the pure titanium dioxide light-assisted positive electrode in Comparative Example 1 before and after illumination.

[0036] Figure 10 This is a comparison of the intermittent illumination long cycle curves of the Schottky heterostructure light-assisted cathode in Example 3 and the pure titanium dioxide light-assisted cathode in Comparative Example 1;

[0037] Figure 11 Constant current intermittent titration diagrams of the Schottky heterostructure light-assisted cathode in Example 3 and the pure titanium dioxide light-assisted cathode in Comparative Example 1 before and after illumination;

[0038] Figure 12 Graphs of ion diffusion coefficients corresponding to constant current intermittent titration graphs before and after illumination for the Schottky heterostructure light-assisted cathode in Example 3 and the pure titanium dioxide light-assisted cathode in Comparative Example 1;

[0039] Figure 13 Impedance frequency scanning diagrams of the Schottky heterostructure light-assisted positive electrode in Example 3 and the pure titanium dioxide light-assisted positive electrode in Comparative Example 1 before and after light irradiation; DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0041] Example 1

[0042] Preparation of Schottky heterostructure light-assisted cathode:

[0043] S1-1. Cut the purchased FTO etched glass substrate to the required size. Ultrasonic clean the glass substrate using detergent, anhydrous ethanol three times, and deionized water three times. Place the substrate in an ultrasonic machine for 10 minutes to remove organic and inorganic impurities on the surface and reduce potential contamination of the film during the preparation process. After cleaning, store the substrate in ethanol.

[0044] S1-2. Take out the glass substrate, dry it in a drying oven, and then put it into the gold spraying instrument. Pump the gold spraying instrument chamber to below 0.5 Pa, set the time to 10 seconds, and the current to 10 mA.

[0045] S1-3, cover the gold-plated FTO glass substrate with a mold, fix it on the substrate tray, put it into the sputtering position in the magnetron sputtering chamber, and place the titanium target on the target head. Pump the sputtering chamber vacuum chamber to 1.0×10 -5 Pa below, invoke the sputtering program, start sputtering, introduce gas, adjust the gas flow to 60 sccm (Ar:O2=50:10), set the sputtering power to 80 W. Pre-sputtering for 1 minute (to remove impurities on the target surface), open the target head cover, and set the sputtering coating time in the program to 28,800 seconds. The product obtained is the Schottky heterostructure light-assisted anode.

[0046] S2-1. Preparation of solid electrolyte: Cover the reserved tabs of the deposited Schottky heterostructure light-assisted positive electrode substrate with a mold, fix the substrate on a tray, place it in the cavity of the magnetron sputtering device, place the lithium phosphate target on the target head, and evacuate the vacuum chamber to 1.0×10 -5 Below Pa, call the RF sputtering program, introduce nitrogen, control the air flow rate to 90sccm, set the power to 100W, pre-sputtering time to 1min, open the target head cover, and set the sputtering coating time in the program to 36000s.

[0047] S2-2. Preparation of negative electrode lithium. Take out the substrate after the electrolyte film sputtering is completed, place it on the evaporation substrate table, add 10-12 lithium sheets, and pump the vacuum chamber to 1.0×10 -5 Pa below, call the program, set the crucible temperature to rise, and start evaporating metallic lithium. According to the deposition rate reading obtained by the quartz crystal sensor, the deposition rate is controlled at 4-6nm s -1 , the deposition thickness of the film is controlled at 2.5μm.

[0048] Example 2

[0049] Preparation of Schottky heterostructure light-assisted cathode:

[0050] S1-1. Cut the purchased FTO etched glass substrate to the required size. Ultrasonic clean the glass substrate using detergent, anhydrous ethanol three times, and deionized water three times. Place the substrate in an ultrasonic machine for 10 minutes to remove organic and inorganic impurities on the surface and reduce potential contamination of the film during the preparation process. After cleaning, store the substrate in ethanol.

[0051] S1-2. Take out the glass substrate, dry it in a drying oven, and then put it into the gold spraying instrument. Pump the gold spraying instrument chamber to below 0.5 Pa, set the time to 20 seconds, and the current to 10 mA.

[0052] S1-3, cover the gold-plated FTO glass substrate with a mold, fix it on the substrate tray, put it into the sputtering position in the magnetron sputtering chamber, and place the titanium target on the target head. Pump the sputtering chamber vacuum chamber to 1.0×10 -5 Pa below, invoke the sputtering program, start sputtering, introduce gas, adjust the gas flow to 60 sccm (Ar:O2=50:10), set the sputtering power to 80 W. Pre-sputtering for 1 minute (to remove impurities on the target surface), open the target head cover, and set the sputtering coating time in the program to 28,800 seconds. The product obtained is the Schottky heterostructure light-assisted anode.

[0053] S2-1. Preparation of solid electrolyte: Cover the reserved tabs of the deposited Schottky heterostructure light-assisted positive electrode substrate with a mold, fix the substrate on a tray, place it in the cavity of the magnetron sputtering device, place the lithium phosphate target on the target head, and evacuate the vacuum chamber to 1.0×10 -5 Below Pa, call the RF sputtering program, introduce nitrogen, control the air flow rate to 90sccm, set the power to 100W, pre-sputtering time to 1min, open the target head cover, and set the sputtering coating time in the program to 36000s.

[0054] S2-2. Preparation of negative electrode lithium. Take out the substrate after the electrolyte film sputtering is completed, place it on the evaporation substrate table, add 10-12 lithium sheets, and pump the vacuum chamber to 1.0×10 -5 Pa below, call the program, set the crucible temperature to rise, and start evaporating metallic lithium. According to the deposition rate reading obtained by the quartz crystal sensor, the deposition rate is controlled at 4-6nm s -1 , the deposition thickness of the film is controlled at 2.5μm.

[0055] Example 3

[0056] Preparation of Schottky heterostructure light-assisted cathode:

[0057] S1-1. Cut the purchased FTO etched glass substrate to the required size. Ultrasonic clean the glass substrate using detergent, anhydrous ethanol three times, and deionized water three times. Place the substrate in an ultrasonic machine for 10 minutes to remove organic and inorganic impurities on the surface and reduce potential contamination of the film during the preparation process. After cleaning, store the substrate in ethanol.

[0058] S1-2. Take out the glass substrate, dry it in a drying oven, and then put it into the gold spraying instrument. Pump the gold spraying instrument chamber to below 0.5 Pa, set the time to 30 seconds, and the current to 10 mA.

[0059] S1-3, cover the gold-plated FTO glass substrate with a mold, fix it on the substrate tray, put it into the sputtering position in the magnetron sputtering chamber, and place the titanium target on the target head. Pump the sputtering chamber vacuum chamber to 1.0×10 -5 Pa below, invoke the sputtering program, start sputtering, introduce gas, adjust the gas flow to 60 sccm (Ar:O2=50:10), set the sputtering power to 80 W. Pre-sputtering for 1 minute (to remove impurities on the target surface), open the target head cover, and set the sputtering coating time in the program to 28,800 seconds. The product obtained is the Schottky heterostructure light-assisted anode.

[0060] S2-1. Preparation of solid electrolyte: Cover the reserved tabs of the deposited Schottky heterostructure light-assisted positive electrode substrate with a mold, fix the substrate on a tray, place it in the cavity of the magnetron sputtering device, place the lithium phosphate target on the target head, and evacuate the vacuum chamber to 1.0×10 -5 Below Pa, call the RF sputtering program, introduce nitrogen, control the air flow rate to 90sccm, set the power to 100W, pre-sputtering time to 1min, open the target head cover, and set the sputtering coating time in the program to 36000s.

[0061] S2-2. Preparation of negative electrode lithium. Take out the substrate after the electrolyte film sputtering is completed, place it on the evaporation substrate table, add 10-12 lithium sheets, and pump the vacuum chamber to 1.0×10 -5 Pa below, call the program, set the crucible temperature to rise, and start evaporating metallic lithium. According to the deposition rate reading obtained by the quartz crystal sensor, the deposition rate is controlled at 4-6nm s -1 , the deposition thickness of the film is controlled at 2.5μm.

[0062] Example 4

[0063] Preparation of Schottky heterostructure light-assisted cathode:

[0064] S1-1. Cut the purchased FTO etched glass substrate to the required size. Ultrasonic clean the glass substrate using detergent, anhydrous ethanol three times, and deionized water three times. Place the substrate in an ultrasonic machine for 10 minutes to remove organic and inorganic impurities on the surface and reduce potential contamination of the film during the preparation process. After cleaning, store the substrate in ethanol.

[0065] S1-2. Take out the glass substrate, dry it in a drying oven, and then put it into the gold spraying instrument. Pump the gold spraying instrument chamber to below 0.5 Pa, set the time to 40 seconds, and the current to 10 mA.

[0066] S1-3, cover the gold-plated FTO glass substrate with a mold, fix it on the substrate tray, put it into the sputtering position in the magnetron sputtering chamber, and place the titanium target on the target head. Pump the sputtering chamber vacuum chamber to 1.0×10 -5 Pa below, invoke the sputtering program, start sputtering, introduce gas, adjust the gas flow to 60 sccm (Ar:O2=50:10), set the sputtering power to 80 W. Pre-sputtering for 1 minute (to remove impurities on the target surface), open the target head cover, and set the sputtering coating time in the program to 28,800 seconds. The product obtained is the Schottky heterostructure light-assisted anode.

[0067] S2-1. Preparation of solid electrolyte: Cover the reserved tabs of the deposited Schottky heterostructure light-assisted positive electrode substrate with a mold, fix the substrate on a tray, place it in the cavity of the magnetron sputtering device, place the lithium phosphate target on the target head, and evacuate the vacuum chamber to 1.0×10 -5 Below Pa, call the RF sputtering program, introduce nitrogen, control the air flow rate to 90sccm, set the power to 100W, pre-sputtering time to 1min, open the target head cover, and set the sputtering coating time in the program to 36000s.

[0068] S2-2. Preparation of negative electrode lithium. Take out the substrate after the electrolyte film sputtering is completed, place it on the evaporation substrate table, add 10-12 lithium sheets, and pump the vacuum chamber to 1.0×10 -5 Pa below, call the program, set the crucible temperature to rise, and start evaporating metallic lithium. According to the deposition rate reading obtained by the quartz crystal sensor, the deposition rate is controlled at 4-6nm s -1 , the deposition thickness of the film is controlled at 2.5μm.

[0069] Comparative Example 1

[0070] Preparation of titanium dioxide positive electrode material:

[0071] S1-1. Cut the purchased FTO etched glass substrate to the required size. Ultrasonic clean the glass substrate using detergent, anhydrous ethanol three times, and deionized water three times. Place the substrate in an ultrasonic machine for 10 minutes to remove organic and inorganic impurities on the surface and reduce potential contamination of the film during the preparation process. After cleaning, store the substrate in ethanol.

[0072] S1-3. Cover the dried FTO glass substrate (not gold-plated) with a mold, fix it on the substrate tray, and place it in the sputtering position in the magnetron sputtering chamber. Place the titanium target on the target head. Pump the sputtering chamber vacuum chamber to 1.0×10 -5Pa below, invoke the sputtering program, start sputtering, introduce gas, adjust the gas flow to 60 sccm (Ar:O2=50:10), set the sputtering power to 80 W. Pre-sputtering for 1 minute (to remove impurities on the target surface), open the target head cover, and set the sputtering coating time in the program to 28,800 seconds. The product obtained is the Schottky heterostructure light-assisted anode.

[0073] S2-1. Preparation of solid electrolyte: Cover the reserved tabs of the deposited Schottky heterostructure light-assisted positive electrode substrate with a mold, fix the substrate on a tray, place it in the cavity of the magnetron sputtering device, place the lithium phosphate target on the target head, and evacuate the vacuum chamber to 1.0×10 -5 Below Pa, call the RF sputtering program, introduce nitrogen, control the air flow rate to 90sccm, set the power to 100W, pre-sputtering time to 1min, open the target head cover, and set the sputtering coating time in the program to 36000s.

[0074] S2-2. Preparation of negative electrode lithium. Take out the substrate after the electrolyte film sputtering is completed, place it on the evaporation substrate table, add 10-12 lithium sheets, and pump the vacuum chamber to 1.0×10 -5 Pa below, call the program, set the crucible temperature to rise, and start evaporating metallic lithium. According to the deposition rate reading obtained by the quartz crystal sensor, the deposition rate is controlled at 4-6nm s -1 , the deposition thickness of the film is controlled at 2.5μm.

[0075] The X-ray diffraction (XRD) characterization of the Schottky heterostructure positive electrode obtained in Examples 2, 3, 4 of the present invention and Comparative Example 1 is as follows: Figure 1 As shown in the figure, the XRD pattern does not show the diffraction peak of TiO2, which indicates that the prepared titanium dioxide thin film cathode material is an amorphous phase.

[0076] The atomic force microscope (SEM) scanning image of the Schottky heterostructure light-assisted positive electrode obtained in Example 3 of the present invention is as follows: Figure 2 As shown, the gold obtained by sputtering using a gold spraying apparatus is in the form of nanoparticles, about 30 nm.

[0077] The scanning electron microscope (TEM) spectrum of the titanium dioxide thin film positive electrode material obtained in Comparative Example 1 of the present invention is as follows: Figure 3 As shown, it can be observed that the thickness of the film is about 100 nm, and EDS elemental analysis proves that the elements are Ti and O.

[0078] The light response It graph of the titanium dioxide thin film cathode material obtained in Comparative Example 1 of the present invention is as follows: Figure 4As shown, it can be seen that under the condition of an external bias voltage of 1V, this titanium dioxide thin film positive electrode material can have a continuously changing current response as the dark and light conditions alternate, which also proves that this material has a strong light response. This also explains the contribution of this amorphous titanium dioxide semiconductor property to increasing the photocurrent, and photogenerated electrons and holes can participate in the electrochemical reaction.

[0079] Comparison of constant current charge and discharge curves of the Schottky heterostructure light-assisted positive electrode obtained in Examples 1, 2, 3, and 4 of the present invention and the pure titanium dioxide light-assisted positive electrode obtained in Comparative Example 1 Figure 5 As shown, by comparing the changes in the discharge specific capacity of Examples 1, 2, 3, 4 and Comparative Example 1, it can be found that compared with the discharge specific capacity of Comparative Example 1 (108.6 mAh g -1 ), Examples 1, 2, 3, and 4 with Schottky heterostructures have higher discharge capacity growth, which are 122.6 mAh g -1 、127.7mAh g -1 、132.3mAh g -1 、122.3mAh g -1 The discharge capacity of Example 3 increased the most, by 21.82%. The charge voltage of Examples 1, 2, 3, and 4 decreased significantly, while the discharge voltage increased significantly. The overall overpotential and polarization decreased significantly, and the crystallinity of the material was improved.

[0080] The cyclic voltammetry curves of the Schottky heterostructure light-assisted positive electrode obtained in Examples 1, 2, 3, and 4 of the present invention and the pure titanium dioxide light-assisted positive electrode obtained in Comparative Example 1 are as follows: Figure 6 As shown, the area of the cyclic voltammetry curve of the gold-plated Schottky heterostructure light-assisted positive electrode is significantly larger than the area of the cyclic voltammetry curve of the pure titanium dioxide light-assisted positive electrode, indicating that the heterostructure improves the capacity.

[0081] The rate performance curves of the Schottky heterostructure light-assisted positive electrode obtained in Examples 1, 2, 3, and 4 of the present invention and the pure titanium dioxide light-assisted positive electrode obtained in Comparative Example 1 are shown in FIG. Figure 7 As shown, at 50mA g -1 , 100mA g -1 , 200mA g -1 , 400mA g -1 , 800mA g -1 , 1600mA g -1 At different rates, the discharge specific capacities of Example 1 are 115.25, 109.1, 97.02, 84.52, 67.38, and 48.01 mAh g -1The discharge specific capacities of Example 2 were 116.23, 109.23, 100.01, 88.22, 69.23, and 49.01 mAh g -1 The discharge specific capacities of Example 3 were 125.41, 116.54, 105.33, 91.90, 72.78, and 50.84 mAh g -1 The discharge specific capacities of Example 4 are 124.32, 106.86, 93.15, 72.12, 53.07, and 37.03 mAh g -1 The discharge specific capacities of comparative example 1 were 115.81, 105.19, 95.77, 79.62, 61.44, and 44.49 mAh g -1 .

[0082] The constant current charge and discharge curves of the Schottky heterostructure light-assisted positive electrode obtained in Example 3 of the present invention and the pure titanium dioxide light-assisted positive electrode obtained in Comparative Example 1 before and after illumination are shown in FIG. Figure 8 As shown in the figure, by comparing the changes in the discharge specific capacity of the two, it can be found that compared with comparative example 1, embodiment 3 with a heterogeneous structure has a higher discharge specific capacity of 123 mAh g -1 (Dark), 209mAh g -1 (light) and more light, the discharge specific capacity increased by 69.92%. Moreover, after light exposure, the charge voltage of Example 3 decreased significantly, the discharge voltage increased significantly, the overall overpotential decreased significantly, and the polarization was further reduced. This indicates that the addition of gold nanoparticles enhances the light absorption capacity, converting more photons into holes and electrons, which then participate in the reaction.

[0083] The cyclic voltammetry curves of the Schottky heterostructure light-assisted positive electrode obtained in Example 3 of the present invention and the pure titanium dioxide light-assisted positive electrode obtained in Comparative Example 1 before and after light irradiation are as follows: Figure 9 As shown, the cyclic voltammetry curve areas of Example 3 and Comparative Example 1 under light are significantly larger than those under darkness, indicating that light enhances capacity. Under light conditions, the oxidation potential of lithium-ion batteries is significantly reduced, the reduction potential is significantly increased, and the redox peak current also increases, demonstrating the contribution of photocurrent to the battery's redox reaction.

[0084] The Schottky heterostructure light-assisted positive electrode obtained in Example 3 of the present invention and the pure titanium dioxide light-assisted positive electrode obtained in Comparative Example 1 were subjected to intermittent illumination for a long cycle. Figure 10As shown, as the cycle progresses, the discharge specific capacity after illumination increases significantly under alternating conditions of darkness and illumination. Compared to Comparative Example 1, Example 3 shows a greater capacity increase after illumination, and this trend is maintained. This demonstrates that the heterostructure material itself responds to the light source consistently and stably. Furthermore, the presence of gold nanoparticles creates a plasmon effect, enhancing light absorption.

[0085] The constant current intermittent titration diagrams of the Schottky heterostructure light-assisted positive electrode obtained in Example 3 of the present invention and the pure titanium dioxide light-assisted positive electrode obtained in Comparative Example 1 before and after illumination are shown in FIG. Figure 11 As shown, the ion diffusion coefficient diagrams corresponding to the constant current intermittent titration diagrams of the Schottky heterostructure light-assisted positive electrode and the pure titanium dioxide light-assisted positive electrode before and after illumination obtained in Example 3 of the present invention and Comparative Example 1 are shown in FIG. Figure 12 As shown in the figure, by comparing the ion diffusion coefficients of the two, it can be found that the ion diffusion coefficients of Example 3 and Comparative Example 1 are approximately the same in the dark. However, under light, compared with Comparative Example 1, Example 3 with a heterogeneous structure has a higher ion diffusion coefficient, with an average diffusion coefficient of 1.25×10 -13 cm 2 s -1 , and a lower relaxation voltage, which also indicates that it has a lower ion migration energy barrier and a stronger and faster ion diffusion ability.

[0086] The impedance frequency scanning diagrams of the Schottky heterostructure light-assisted positive electrode obtained in Example 3 of the present invention and the pure titanium dioxide light-assisted positive electrode obtained in Comparative Example 1 before and after light irradiation are shown in FIG. Figure 13 As shown, comparing Example 3 and Comparative Example 1, the impedance frequency scan graphs of both under light obviously have smaller semicircles than the impedance frequency scan graphs under darkness, indicating lower charge transfer resistance. Example 3 is 165Ω under light conditions and 197Ω under dark conditions, while Comparative Example 1 is 141Ω under light conditions and 159Ω under dark conditions, which also shows that light can promote the rapid transfer of electrons.

[0087] It should be noted that the above content merely illustrates the technical idea of the present invention and cannot be used to limit the scope of protection of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications all fall within the scope of protection of the claims of the present invention.

Claims

1. A light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure cathode, characterized in that: It mainly consists of a lithium negative electrode, a solid electrolyte, a Schottky heterostructure light-assisted positive electrode, and FTO conductive glass with a transparent substrate. The Schottky heterostructure light-assisted positive electrode is composed of titanium dioxide and gold.

2. The light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode according to claim 1, characterized in that: The solid electrolyte is amorphous lithium phosphorus oxygen nitrogen (LIPON), that is, nitrogen-doped lithium phosphate; the light-assisted rechargeable lithium ion battery is an all-solid-state thin-film battery.

3. The light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode according to claim 1, characterized in that: The method for preparing a Schottky heterostructure light-assisted positive electrode comprises the following steps: S1-1. Cut the purchased FTO etching glass substrate into the required size. Clean the glass substrate to remove organic and inorganic impurities on the surface and reduce the possibility of impurity contamination of the film during the preparation process. After the substrate is cleaned, store it in ethanol. S1-2. Take out the glass substrate and dry it in a drying oven. After drying, place the substrate in a gold spraying apparatus for gold plating. S1-3. Cover the gold-plated FTO glass substrate with a mold, fix it on the substrate tray, and place it in the sputtering position in the magnetron sputtering chamber. Use a titanium target to perform radio frequency controlled sputtering in an argon oxygen environment to deposit a titanium dioxide film on the substrate. The obtained product is the Schottky heterostructure light-assisted positive electrode.

4. The light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode according to claim 3, characterized in that: In step S1-1, the cleaning is performed using a detergent, anhydrous ethanol ultrasonic cleaning 3 times, and deionized water ultrasonic cleaning 3 times, and then placed in an ultrasonic machine for cleaning for 10 minutes.

5. The light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode according to claim 3, characterized in that: In step S1-2, the chamber of the spray metallurgical instrument is evacuated to below 0.5 Pa, the time is set to 10-40 seconds, and the current is 10 mA.

6. The light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode according to claim 3, characterized in that: In step S1-3, the sputtering chamber is evacuated to a vacuum of 1.0×10 -5 Pa below, call the sputtering program, start sputtering, introduce gas, adjust the gas flow to 60 sccm (Ar:O2=50:10), set the sputtering power to 80 W. Pre-sputtering time is 1 minute (to remove impurities on the target surface), open the target head cover, and set the sputtering coating time in the program to 28800 seconds.

7. A method for preparing a light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode, characterized in that: The following steps are involved: S2-1. Cover the reserved tabs of the deposited Schottky heterostructure light-assisted positive electrode substrate with a mold, fix the substrate on a tray, and place it in the chamber of the magnetron sputtering device. The electrolyte uses a lithium phosphate target and is deposited on the positive electrode titanium dioxide film under a nitrogen environment at room temperature to obtain a LIPON inorganic solid electrolyte; S2-2, taking out the substrate after the electrolyte film is sputtered, placing it on the evaporation substrate table, and plating lithium by thermal evaporation under a vacuum environment. The battery finally taken out is the light-assisted rechargeable lithium-ion battery; Wherein, the Schottky heterostructure light-assisted positive electrode in step S2-1 is the Schottky heterostructure light-assisted positive electrode according to any one of claims 3-6.

8. The method for preparing a light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode according to claim 7, wherein: In step S2-1, the vacuum chamber is evacuated to 1.0×10 -5 Below Pa, call the RF sputtering program, introduce nitrogen, control the air flow rate to 90sccm, set the power to 100W, pre-sputtering time to 1min, open the target head cover, and set the sputtering coating time in the program to 36000s.

9. The method for preparing a light-assisted rechargeable lithium-ion battery based on a Schottky heterostructure positive electrode according to claim 7, wherein: In step S2-2, the vacuum chamber is evacuated to 1.0×10 -5 Pa below, call the program, set the crucible temperature to rise, and start evaporating metallic lithium. According to the deposition rate reading obtained by the quartz crystal sensor, the deposition rate is controlled at 4-6nm s -1 , the deposition thickness of the film is controlled at 2.5μm.

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