Background
Currently, wearable electronic devices are being widely used in people's lives. The flexible energy storage device is a key core component of the wearable electronic equipment. The characteristic of personal wear puts higher requirements on the safety of the energy storage device used by the device. Although batteries have a high energy density, the volatility and flammability of organic electrolytes pose a serious safety hazard. Therefore, the water system energy storage device has the advantages of high charging speed, high safety, long cycle life and the like, and can meet the requirements of wearable electronic equipment.
The water system energy storage device has high ionic conductivity, so that the electrolyte/the electrode can fully react, and the water system energy storage device has excellent electrochemical performance. However, the water-based energy storage device provided by the related art has the problems of being incapable of bending, inconvenient to carry and the like, so that the water-based energy storage device is not suitable for being applied to flexible electronic equipment. Meanwhile, the all-solid-state flexible energy storage device can be well applied to flexible displays, portable electronic devices, wearable devices and other equipment due to the characteristics of good flexibility, bendability, portability, stretchability and the like, but the problems of contact resistance between the stored solid electrolyte and the electrodes, ion transmission and the like are still difficult to solve, so that the electrochemical performance of the all-solid-state flexible energy storage device is far lower than that of a water-based energy storage device.
Disclosure of Invention
The invention aims to provide a copper oxide nano array electrode, a copper oxide nano array non-solid-state water system flexible energy storage device and a preparation method thereof, the copper oxide nano array electrode prepared by the method and the copper oxide nano array non-solid-state water system flexible energy storage device prepared by the copper oxide nano array electrode meet the excellent electrochemical performance of the water system energy storage device and meet the portability and the wearability of a solid-state flexible super capacitor.
The invention is realized by the following steps:
in a first aspect, an embodiment of the present invention provides a method for preparing a copper oxide nano array electrode, including using a metal substrate and an alkaline solution to prepare a metal hydroxide electrode by a direct current stable power supply anodic oxidation method.
In an alternative embodiment, the method further comprises washing the metal substrate with an acid solution and an alcohol solution;
and then, preparing the metal hydroxide electrode by using the cleaned metal substrate and an alkaline solution through a direct-current stable power supply anodic oxidation method.
In an alternative embodiment, the metal substrate comprises copper.
In an alternative embodiment, the basic solution is a KOH solution with a concentration of 2 to 6M.
In an alternative embodiment, the anodization voltage of the direct current regulated power supply anodization process is 1-3V.
In an alternative embodiment, the method further comprises obtaining the metal oxide nanowires by dehydrating the metal hydroxide electrode by sintering.
In an alternative embodiment, the sintering of the metal hydroxide electrode is performed under an argon atmosphere; preferably, sintering comprises holding at 140-160 ℃ for a period of time and then holding at 200-350 ℃.
In a second aspect, embodiments of the present invention provide a copper oxide nano-array electrode, which is prepared by the method for preparing a copper oxide nano-array electrode according to any one of the foregoing embodiments.
In a third aspect, embodiments of the present invention provide a non-solid-state water-based flexible energy storage device with a copper oxide nano array, including the copper oxide nano array electrode of the foregoing embodiment.
In a fourth aspect, an embodiment of the present invention provides a method for preparing a non-solid-state water-based flexible energy storage device of a copper oxide nano array according to the foregoing embodiment, including: the copper oxide nano array electrode is separated by a diaphragm, symmetrically assembled in water-based electrode liquid and encapsulated in a plastic film.
The preparation method of the copper oxide nano array electrode of the embodiment of the invention has the beneficial effects that: according to the preparation method of the copper oxide nano array electrode provided by the embodiment of the invention, the nano array is prepared on the metal substrate by a direct anodic oxidation method, the specific surface area of the material can be effectively improved, secondary preparation of the electrode and addition of a certain proportion of binder are not required, and the internal resistance of the electrode can be effectively reduced; the preparation method is simple to operate, and the obtained copper oxide nano array electrode not only meets the excellent electrochemical performance of a water system energy storage device, but also meets the portability and the wearability of the solid flexible super capacitor.
The copper oxide nano array electrode of the embodiment of the invention has the beneficial effects that: the copper oxide nano array electrode disclosed by the embodiment of the invention is prepared by the preparation method, and not only can the excellent electrochemical performance of a water system energy storage device be met, but also the portability and the wearability of a solid flexible super capacitor can be met.
The non-solid-state water system flexible energy storage device of the copper oxide nano array has the beneficial effects that: the non-solid-state water system flexible energy storage device of the copper oxide nano array provided by the embodiment of the invention comprises the copper oxide nano array electrode, so that the excellent electrochemical performance of the water system energy storage device is met, the portability and the wearability of the solid-state flexible super capacitor are met, and the non-solid-state water system flexible energy storage device is conveniently applied to wearable electronic equipment.
The preparation method of the non-solid-state water system flexible energy storage device of the copper oxide nano array has the beneficial effects that: according to the preparation method of the non-solid-state water system flexible energy storage device of the copper oxide nano array, the non-solid-state water system flexible energy storage device is prepared by using the copper oxide nano array electrode, so that the prepared non-solid-state water system flexible energy storage device not only meets excellent electrochemical performance of the water system energy storage device, but also meets the portability and the wearability of a solid flexible super capacitor, and the preparation method is convenient to use in wearable electronic equipment.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The features and properties of the present invention are described in further detail below with reference to examples.
The invention provides a preparation method of a copper oxide nano array electrode, which comprises the step of preparing a metal hydroxide electrode by utilizing a metal substrate and an alkaline solution through a direct-current stable power supply anodic oxidation method.
Thus, the nano-array is prepared on the metal substrate by the direct anodic oxidation method, the specific surface area of the material can be effectively improved, secondary preparation of the electrode and addition of a certain proportion of binder are not needed, and the internal resistance of the electrode can be effectively reduced; the preparation method is simple to operate, and the obtained copper oxide nano array electrode not only meets the excellent electrochemical performance of a water system energy storage device, but also meets the portability and the wearability of the solid flexible super capacitor.
The preparation method of the copper oxide nano array electrode provided by the invention specifically comprises the following steps:
cleaning the metal substrate with an acid solution and an alcohol solution; specifically, the metal substrate is ultrasonically cleaned in deionized water, an acid solution and ethanol in sequence, and is dried in vacuum.
And then, preparing the metal hydroxide electrode by using an alkaline solution with a certain concentration through a direct-current stable power supply anodic oxidation method.
And dehydrating the metal hydroxide electrode by sintering to obtain the metal oxide nanowire.
Wherein the metal substrate comprises copper; specifically, the metal substrate is a commercial metal copper sheet with good electrical conductivity.
The alkaline solution is KOH solution, the concentration is 2-6M; anodeThe oxidation voltage is 1-3V, the time is 20-60min, the anode in the electrolytic cell is a copper sheet, the cathode is a platinum sheet, the metal hydroxide is Cu (OH)2The metal oxide is CuO.
The high temperature sintering of the metal hydroxide electrode is carried out under an argon atmosphere. Preferably, the high-temperature sintering comprises the steps of preserving heat at 140-160 ℃ for a period of time and then preserving heat at 200-350 ℃; specifically, the high-temperature sintering comprises the steps of insulating at 140-160 ℃ for about 3h and then insulating at 200-350 ℃ for about 3 h.
The copper oxide nano array is prepared on the substrate with the flexible copper sheet by a direct anodic oxidation method, so that the specific surface area of the material can be effectively improved, secondary preparation of the electrode and addition of a certain proportion of a binder are not required, and the internal resistance of the electrode can be effectively reduced.
The acidic solution may be hydrochloric acid, oxalic acid, sulfuric acid, or the like, and the concentration of the acidic solution may be any concentration, for example: 1mol/L, 2mol/L, 0.5mol/L, etc., may be selected as necessary, and are not particularly limited herein. The volume concentration of the ethanol solution may be 95%, 85%, etc., and is not particularly limited.
The copper oxide nano array electrode prepared by the preparation method of the copper oxide nano array electrode can be used for preparing a non-solid water system flexible energy storage device of a copper oxide nano array, and the preparation method comprises the following steps: the copper oxide nano array electrode is separated by a diaphragm, symmetrically assembled in water-based electrode liquid and encapsulated in a plastic film. The separator and the water-based electrode liquid are similar to those of the related art, and are not described in detail here.
The following examples will be described in detail with respect to the copper oxide nanoarray electrode and the method for manufacturing the non-solid-state water-based flexible energy storage device of the copper oxide nanoarray.
Example 1
Preparing a copper oxide nano array electrode:
a. ultrasonically cleaning a commercial metal copper sheet in deionized water, an acid solution and ethanol in sequence, and drying in vacuum;
b. 6M KOH electrolyte is prepared, a direct current stable power supply is used,preparing Cu (OH) by an anodic oxidation method at a voltage of 1V for 20min2An electrode;
c. and (3) preserving heat for 3h at 150 ℃ and then preserving heat for 3h at 200 ℃ under the argon atmosphere. Mixing Cu (OH)2And (5) dehydrating to prepare the CuO nanowire.
The copper oxide nano array electrode material is characterized as follows:
the surface morphology of the samples was characterized by Scanning Electron Microscopy (SEM), as shown in fig. 1. As can be seen from FIG. 1, a uniform array is directly grown on the surface of the metal copper sheet by an anodic oxidation method, so that the specific surface area of the material is effectively increased, secondary preparation of the electrode and addition of a certain proportion of a binder are not required, and the internal resistance of the electrode can be effectively reduced.
The surface morphology of the sample was characterized by XRD spectrogram, as shown in fig. 2. As can be seen in fig. 2, it is demonstrated that CuO grows on commercial metallic copper sheets.
The electrochemical test method for the prepared copper oxide nano array electrode comprises the following steps: directly immersing the copper oxide nano array electrode into a 2M KOH solution, changing different scanning rates to obtain cyclic voltammetry curves in a three-electrode system (the copper oxide nano array electrode is a working electrode, a platinum sheet is a counter electrode, and Ag/AgCl is a reference electrode) with a voltage window of 0-0.5V, and obtaining the cyclic voltammetry curves at different scanning rates as shown in FIG. 3; calculating the area specific capacities at different scan rates, as shown in fig. 4; at 105Electrochemical impedance spectroscopy was performed at a frequency of HZ to 0.01HZ, as shown in fig. 5.
Electrochemical testing was as follows:
in the copper oxide nano-array three-electrode system, the scanning speed is from 5mV s-1~200mV s-1Obtaining cyclic voltammograms at various rates, the cyclic voltammograms of the electrode still maintaining a good shape as the rate increases, as shown in fig. 3; due to the good electron and ion transport capacity of the electrode, the electrode has 5mV s-1When the specific area capacity of the electrode is 58.54mF cm-2As shown in fig. 4; the solution resistance of this electrode was only about 0.57ohm and the high frequency region slope was also large, indicating electrolysis in KOHThe electrode has good electrochemical performance in liquid, as shown in figure 5.
Preparing a non-solid water system flexible energy storage device of the copper oxide nano array by using the prepared copper oxide nano array electrode: the copper oxide nano array electrode is separated by a diaphragm, symmetrically assembled in water-based electrode liquid and then encapsulated in a plastic film.
Two copper oxide nano array electrodes are assembled into a symmetrical supercapacitor through a diaphragm, and the electrochemical test method comprises the following steps: assembling the two copper oxide nano array electrodes by using a diaphragm, immersing the two copper oxide nano array electrodes into a plastic bag of 2M KOH solution, sealing the plastic bag by using a sealing machine, wherein the voltage window of a cyclic voltammetry curve is 0-1V, and changing different scanning rates to obtain cyclic voltammetry curves at different scanning rates, as shown in FIG. 6; calculating the area specific capacities at different scan rates, as shown in fig. 7; at 105Electrochemical impedance spectroscopy was performed at a frequency of HZ to 0.01HZ, as shown in fig. 8.
In a symmetrical supercapacitor two-electrode system, the scan rate is from 5mV s-1~200mV s-1Obtaining cyclic voltammograms at various rates, the cyclic voltammograms of the electrode still maintaining a good shape as the rate increases, as shown in fig. 6; due to the good electron and ion transport capacity of the electrode, the electrode has 5mV s-1When the specific area capacity of the electrode is 87.22mF cm-2As shown in fig. 7; the solution resistance of the electrode was only about 0.35ohm and the high frequency region slope was also large, indicating that the electrode has good electrochemical performance in KOH electrolyte, as shown in figure 8.
As shown in fig. 9, a real image showing the flexibility of the prepared water system flexible symmetrical super capacitor at a bending degree of 0-180 degrees and the lighting of the LED lamp after the three symmetrical super capacitors are connected in series is shown. The supercapacitor prepared by the method has the excellent electrochemical performance of a water system supercapacitor, has the advantages of a solid flexible supercapacitor, such as portability and wearability, and can be directly applied to daily electronic equipment of people.
Example 2
Preparing a copper oxide nano array electrode:
ultrasonically cleaning a commercial metal copper sheet in deionized water, an acid solution and ethanol in sequence, and drying in vacuum;
preparing 2M KOH electrolyte, using a direct current stable power supply, preparing Cu (OH) by an anodic oxidation method at a voltage of 3V for 60min2An electrode;
under the argon atmosphere, the temperature is firstly preserved for 2h at 160 ℃ and then preserved for 2.5h at 250 ℃. Mixing Cu (OH)2And (5) dehydrating to prepare the CuO nanowire.
Preparing a non-solid water system flexible energy storage device of the copper oxide nano array by using the prepared copper oxide nano array electrode: the copper oxide nano array electrode is separated by a diaphragm, symmetrically assembled in water-based electrode liquid and then encapsulated in a plastic film.
Example 3
Preparing a copper oxide nano array electrode:
ultrasonically cleaning a commercial metal copper sheet in deionized water, an acid solution and ethanol in sequence, and drying in vacuum;
preparing 3M KOH electrolyte, using a direct current stable power supply, preparing Cu (OH) by an anodic oxidation method at the voltage of 2V for 40min2An electrode;
under the argon atmosphere, the temperature is firstly preserved for 3.5h at 140 ℃ and then preserved for 2h at 550 ℃ through high temperature. Mixing Cu (OH)2And (5) dehydrating to prepare the CuO nanowire.
Preparing a non-solid water system flexible energy storage device of the copper oxide nano array by using the prepared copper oxide nano array electrode: the copper oxide nano array electrode is separated by a diaphragm, symmetrically assembled in water-based electrode liquid and then encapsulated in a plastic film.
Example 4
Preparing a copper oxide nano array electrode:
ultrasonically cleaning a commercial metal copper sheet in deionized water, an acid solution and ethanol in sequence, and drying in vacuum;
preparing 5M KOH electrolyte, using a direct current stable power supply, and preparing Cu (OH) by an anodic oxidation method at the voltage of 1.5V for 30min2An electrode;
under the argon atmosphere, the temperature is firstly preserved for 2.5h at 150 ℃ and then preserved for 3h at 270 ℃. Mixing Cu (OH)2And (5) dehydrating to prepare the CuO nanowire.
Preparing a non-solid water system flexible energy storage device of the copper oxide nano array by using the prepared copper oxide nano array electrode: the copper oxide nano array electrode is separated by a diaphragm, symmetrically assembled in water-based electrode liquid and then encapsulated in a plastic film.
Example 5
Preparing a copper oxide nano array electrode:
ultrasonically cleaning a commercial metal copper sheet in deionized water, an acid solution and ethanol in sequence, and drying in vacuum;
preparing 3M KOH electrolyte, using a direct current stable power supply, preparing Cu (OH) by an anodic oxidation method at a voltage of 4V for 45min2An electrode;
and (3) preserving heat for 3h at 150 ℃ and then preserving heat for 3h at 230 ℃ under the argon atmosphere. Mixing Cu (OH)2And (5) dehydrating to prepare the CuO nanowire.
Preparing a non-solid water system flexible energy storage device of the copper oxide nano array by using the prepared copper oxide nano array electrode: the copper oxide nano array electrode is separated by a diaphragm, symmetrically assembled in water-based electrode liquid and then encapsulated in a plastic film.
In conclusion, the preparation method of the copper oxide nano array electrode provided by the invention prepares the nano array on the metal substrate by a direct anodic oxidation method, can effectively improve the specific surface area of the material, does not need secondary preparation of the electrode and addition of a certain proportion of binder, and can effectively reduce the internal resistance of the electrode; the preparation method is simple to operate, and the obtained copper oxide nano array electrode not only meets the excellent electrochemical performance of a water system energy storage device, but also meets the portability and the wearability of the solid flexible super capacitor; the non-solid-state water system flexible energy storage device of the copper oxide nano array is prepared from the copper oxide nano array electrode prepared by the preparation method, meets the requirements of wearable electronic equipment, and is convenient to use in the wearable electronic equipment.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.