CN102709071A - Conducting polymer modified super capacitor and manufacturing method thereof - Google Patents

Abstract

A conductive polymer modified supercapacitor and a preparation method thereof belong to the technical field of supercapacitors. The invention adopts MEMS technology to integrate a plurality of miniature capacitors into a single silicon substrate, and the plurality of miniature capacitors are connected in parallel (or connected in parallel after being connected in series) to form supercapacitors. All microcapacitors consist of a pair of microgrooves with a spacer between them, the height of which is lower than the depth of the microgrooves; the walls of the microgrooves are deposited with metal electrode layers and conductive polymer films ; The interior of the micro-groove is filled with electrolyte and then sealed and packaged. In the process of making microcapacitors, a simple and effective direct chemical polymerization conductive polymer film is used on the metal electrode layer to modify the capacitor electrodes to increase the specific capacity of the microelectrodes and reduce the equivalent series resistance. The conductive polymer modified supercapacitor provided by the invention has the characteristics of large specific capacity and high integration, and can be used as various power sources or energy storage devices.

Description

A kind of conductive polymer modified supercapacitor and preparation method thereof

technical field

The invention belongs to the technical field of supercapacitors, in particular to supercapacitors modified by conductive polymers and a preparation method thereof.

Background technique

With the development of social economy, people pay more and more attention to green energy and ecological environment. Supercapacitors, also known as electrochemical capacitors, are a new type of energy storage device between traditional capacitors and batteries. Compared with traditional batteries, supercapacitors have higher energy density, power density and long cycle life. As a clean and efficient new energy storage device, more and more researchers have paid attention to them. The development of supercapacitor technology The core is the electrode material. According to the definition of supercapacitors by Professor BEConway, an international authority in the field of supercapacitor research, supercapacitors can be divided into two categories: one is electric double layer capacitors, and the representative material is porous carbon materials (activated carbon, carbon fiber, carbon nanotubes, etc.); One type is a pseudocapacitor, and the representative materials are metal oxides (RuO ₂ , IrO _{2 ,} etc.) and conductive polymers (polyaniline, polypyrrole, polythiophene and their derivatives).

Supercapacitors prepared from conductive polymers have the advantages of low cost, high capacity, short charge-discharge time, environmental friendliness, and high safety. Therefore, research on conductive polymers as electrode materials has attracted widespread interest. At present, conductive polymer films are mostly combined with inorganic materials to prepare supercapacitor electrodes by electrochemical polymerization. Among them, the patent applications involved include a preparation method of conductive polyaniline polypyrrole composite film (document number: CN102020845A); a preparation method of conductive polypyrrole (document number: CN101979438A); three-dimensional structure polypyrrole microelectrode and its manufacture method (document number: CN101950685A). The conductive polymer film prepared above is used to modify electrodes, and has high specific capacity and good device performance, but the electrochemical process is complex and the controllability is weak. At present, there are few reports on the preparation of conductive polymer film electrodes by direct oxidation polymerization. The film prepared by this method not only has excellent performance, but also has a simple method and is easy to operate.

Micro-electro-mechanical systems (MEMS) are characterized by mobility, self-control, and integration, and are one of the most important technological innovations in recent years. When a subsystem can be integrated on a chip, the power supply must also complete the revolution of miniaturization and miniaturization. MEMS micro-energy system is based on MEMS technology. It integrates one or more power supply devices into a micro-system with micron-level characteristic size and centimeter-level appearance size. It can realize long-term, high-efficiency, multi-mode power supply, and is especially suitable for traditional Certain special environments where power cannot be supplied. The miniaturization, miniaturization and integration of electronic products are the major trends in the development of technology in the world today, and the miniaturization and integration of power supplies are also the major trends in the development of technology in the world today.

Contents of the invention

Aiming at the technical problems of single method and complex process existing in the existing micro-supercapacitor electrode preparation methods, the invention provides a conductive polymer-modified micro-supercapacitor and a preparation method thereof. The conductive polymer-modified micro-supercapacitor provided by the present invention is formed by connecting several micro-capacitor structures in series and in parallel. Each micro-capacitor structure is manufactured in the same silicon substrate material by MEMS technology, and a conductive polymer film is deposited on the surface of the metal electrode. It has the characteristics of large specific capacity and high integration.

Technical scheme of the present invention is as follows:

A conductive polymer modified supercapacitor includes a silicon substrate and several microcapacitors arranged in the silicon substrate.

All microcapacitors have the same structure; each microcapacitor includes a pair of microgrooves arranged in the silicon substrate, and there is an isolation post between the two microgrooves, and the height of the isolation column is lower than that of the microgroove. Depth; metal electrode layers are deposited on the walls of the two micro-grooves, and conductive polymer films are deposited on the surface of the metal electrode layers; two micro-grooves with metal electrode layers and conductive polymer films are deposited as the cathode and the conductive polymer films of the micro-capacitors respectively. Anode; Two micro-grooves are filled with electrolyte and then sealed and packaged inside the silicon substrate.

All microcapacitors are connected in parallel to form a supercapacitor; or the same number of microcapacitors are connected in series to form a series branch; then several series branches are connected in parallel to form a supercapacitor.

The supercapacitor modified by the above conductive polymer, wherein the metal electrode layer material is metal nickel, aluminum, platinum or titanium, etc.; the conductive polymer film is polyaniline film, polypyrrole film or polythiophene film; the electrolyte It is the aqueous solution of H ₂ SO ₄ , H ₃ PO ₄ , NaNO ₃ or KOH. Among them, the concentration of H ₂ SO ₄ aqueous solution is between 0.5 and 1 mol/L, the concentration of H ₃ PO ₄ aqueous solution is between 0.5 and 1 mol/L, the concentration of NaNO ₃ aqueous solution is between 1 and 3 mol/L, and the concentration of KOH aqueous solution is The concentration is between 0.5 and 1mol/L.

It should be noted that, in the microcapacitor structure formed by each pair of microgrooves, the function of the spacer between the two microgrooves is to prevent the short circuit of the two poles of the microcapacitor; at the same time, the height of the spacer should be lower than the depth of the microgroove , to ensure that the electrolyte can flow between the two poles.

A preparation method for a supercapacitor modified by a conductive polymer, comprising the following steps:

Step 1: Using two silicon substrates with the same shape and size, etching several pairs of micro-grooves in the same area on each silicon substrate, with the same isolation columns between each pair of micro-grooves;

Step 2: Align the micro-grooves of two silicon substrates face to face, and bond them to obtain several pairs of micro-grooves enclosed in the silicon material;

Step 3: Etch away the silicon material above the entire area corresponding to each pair of micro-grooves plus the isolation column between the pair of micro-grooves, so that the height of the isolation column between each pair of micro-grooves is lower than that of the micro-groove the depth of the groove;

Step 4: Deposit a metal electrode layer on the inner walls of all micro-grooves and lead them out with metal wires;

Step 5: depositing a conductive polymer film on the surface of the metal electrode layer obtained in step 4;

Step 6: Fill the micro-groove with electrolyte solution, and then seal the package; each pair of micro-grooves after sealing and packaging forms a micro-capacitor;

Step 7: All microcapacitors are connected in parallel to each other to form a supercapacitor; or the same number of microcapacitors are first connected in series to form a series branch; then several series branches are connected in parallel to form a supercapacitor.

In the preparation method of the supercapacitor modified by the above-mentioned conductive polymer, the metal electrode layer material is metal nickel, aluminum, platinum or titanium, etc.; the conductive polymer film is a polyaniline film, a polypyrrole film or a polythiophene film; The electrolyte is 0.5-1 mol/L H ₂ SO ₄ , 0.5-1 mol/L H ₃ PO ₄ , 1-3 mol/L NaNO ₃ or 0.5-1 mol/L KOH aqueous solution.

The conductive polymer-modified supercapacitor provided by the present invention is composed of a plurality of microcapacitors connected in series and in parallel in a single silicon substrate material; The isolation column between two micro-grooves (the height of the isolation column is lower than the depth of the micro-groove), the metal electrode layer and the conductive polymer film are deposited successively on the inner wall of the micro-groove, and the deposited metal electrode layer and the conductive polymer film are deposited on the micro After filling the groove with solution solution, it is sealed and packaged to form a microcapacitor, and multiple microcapacitors are connected in series and parallel to form a supercapacitor. The conductive polymer modified supercapacitor provided by the invention has the characteristics of large specific capacity and high integration, and can be used as various power sources or energy storage devices.

Description of drawings

FIG. 1 is a schematic diagram of a silicon nitride layer coated on a silicon substrate, 1 is silicon nitride, and 2 is a silicon substrate.

Fig. 2 is a schematic diagram of the micro groove structure on a monolithic silicon substrate.

Figure 3 is a schematic diagram of silicon-silicon bonding.

Fig. 4 is a schematic diagram of the micro groove structure on the silicon substrate after bonding and etching.

FIG. 5 is a schematic diagram of depositing a metal electrode layer on the inner wall of a micro-groove, and 3 is a metal electrode layer.

FIG. 6 is a schematic diagram of depositing a conductive polymer film on the surface of a metal electrode layer, and 4 is a conductive polymer film.

FIG. 7 is a schematic structural diagram of a plurality of microcapacitors connected in parallel to form a supercapacitor.

Detailed ways

The present invention will be further described below in conjunction with the embodiments.

A preparation method for a supercapacitor modified by a conductive polymer, comprising the following steps:

Step 1: Take two clean silicon substrates with the same shape and size, use PECVD process to coat a layer of silicon nitride on the surface (as shown in Figure 1), and then use photolithography to coat the same silicon substrate on each silicon substrate. Several pairs of micro-grooves are regionally etched, and there are identical isolation columns between each pair of micro-grooves (as shown in FIG. 2 ).

Step 2: Align and bond the micro grooves of two silicon substrates face to face to obtain several pairs of micro grooves enclosed in silicon material (as shown in Figure 3).

Step 3: Etch away the silicon material above the entire area corresponding to each pair of micro-grooves plus the isolation column between the pair of micro-grooves, so that the height of the isolation column between each pair of micro-grooves is lower than that of the micro-groove The depth of the groove (as shown in Figure 4).

Step 4: Deposit metal electrode layers on the inner walls of all micro-grooves and lead them out with metal wires (as shown in Figure 5); the deposition method of metal electrode layers can be vacuum evaporation, and the electrode materials can be nickel, aluminum, platinum, titanium and other metals.

Step 5: deposit conductive polymer thin film on the metal electrode layer surface gained in step 4; Concrete method is, at first ferric trichloride or iron p-toluenesulfonate oxidant, stearic acid auxiliary film-forming agent, chloroform solvent are pressed The ratio of 2:1:10 is mixed evenly, and then the mixed solution is spread on the subphase (deionized water) with a micro-syringe; then, a layer of tens to hundreds of nanometers thick is obtained on the surface of the metal electrode layer by pulling process. Oxidant film; finally, the oxidant film is immersed in aniline monomer, pyrrole monomer or thiophene monomer, taken out and dried after 30 minutes, and rinsed with ethanol to obtain a layer of conductive polymer film on the metal electrode (as shown in Figure 6 shown).

Step 6: Fill the micro-groove with electrolyte, and then seal the package; each pair of micro-grooves after sealing and packaging forms a micro-capacitor; the electrolyte can be acidic or alkaline electrolyte, such as 0.5ml/L~1mol/ L sulfuric acid (H ₂ SO ₄ ), 0.5mol/L~1mol/L phosphoric acid (H ₃ PO ₄ ), 1mol/L~3mol/L sodium nitrate (NaNO ₃ ), 0.5mol/L~1mol/L potassium hydroxide (KOH) etc.

Step 7: All microcapacitors are connected in parallel to each other to form a supercapacitor; or the same number of microcapacitors are first connected in series to form a series branch; then several series branches are connected in parallel to form a supercapacitor.

The invention utilizes MEMS technology to integrate multiple microcapacitors into a single silicon substrate, and the multiple microcapacitors are connected in parallel (or connected in parallel after being connected in series) to form supercapacitors. In the process of microcapacitor fabrication, a simple and effective direct chemical polymerization conductive polymer film is used on the evaporated metal electrode to modify the capacitor electrode to increase the specific capacity of the microelectrode and reduce the equivalent series resistance (ESR). The conductive polymer modified supercapacitor provided by the invention has the characteristics of large specific capacity and high integration, and can be used as various power sources or energy storage devices.

Claims (9)

1. a conducting polymer modified ultracapacitor comprises silicon chip and is arranged at several button capacitors in the silicon chip;

All button capacitors have identical structure; Each button capacitor comprises a pair of micro-recesses that is arranged in the silicon chip, has an insulated column between two micro-recesses, and the height of said insulated column is lower than the degree of depth of micro-recesses; The cell wall of two micro-recesses deposits metal electrode layer, and the metal electrode layer surface deposition has conducting polymer thin film; Two micro-recesses that deposited metal electrode layer and conducting polymer thin film are respectively as the negative electrode and the anode of button capacitor; Sealed package is inner in silicon chip behind two the inner perfusion of micro-recesses electrolyte;

All button capacitors are parallel with one another, form ultracapacitor; Perhaps connect each other by the button capacitor of equal number earlier, form a series arm; Parallel with one another by several series arms again, form ultracapacitor.

2. conducting polymer modified ultracapacitor according to claim 1 is characterized in that, said metal electrode layer material is metallic nickel, aluminium, platinum or titanium.

3. conducting polymer modified ultracapacitor according to claim 1 is characterized in that, said conducting polymer thin film is polyaniline film, film of poly pyrrole or polythiophene film.

4. conducting polymer modified ultracapacitor according to claim 1 is characterized in that, said electrolyte is the H of 0.5～1mol/L ₂SO ₄, 0.5 ~ 1mol/L H ₃PO ₄, 1 ~ 3mol/L NaNO ₃Or the KOH aqueous solution of 0.5～1mol/L.

5. the preparation method of a conducting polymer modified ultracapacitor may further comprise the steps:

Step 1: adopt the two plate shapes silicon chip identical with size, regional etching identical on every silicon chip is some to micro-recesses, has identical insulated column between every pair of micro-recesses;

Step 2: the micro-recesses of two silicon chips is aimed at Face to face, and bonding, obtain some to being closed in the micro-recesses in the silicon materials;

Step 3: every pair of micro-recesses is added these silicon materials to the pairing overall region of the insulated column between micro-recesses top etch away, make the height of the insulated column between every pair of micro-recesses be lower than the degree of depth of micro-recesses;

Step 4:, and draw with plain conductor at all micro-recesses inwall deposit metal electrodes layers;

Step 5: at step 4 gained metal electrode layer surface deposition conducting polymer thin film;

Step 6: in micro-recesses, pour into electrolyte, then sealed package; After the sealed package each forms a button capacitor to micro-recesses;

Step 7: all button capacitors are parallel with one another, form ultracapacitor; Perhaps connect each other by the button capacitor of equal number earlier, form a series arm; Parallel with one another by several series arms again, form ultracapacitor.

6. the preparation method of conducting polymer modified ultracapacitor according to claim 5 is characterized in that said metal electrode layer material is metallic nickel, aluminium, platinum or titanium.

7. the preparation method of conducting polymer modified ultracapacitor according to claim 5 is characterized in that said conducting polymer thin film is polyaniline film, film of poly pyrrole or polythiophene film.

8. the preparation method of conducting polymer modified ultracapacitor according to claim 5 is characterized in that said electrolyte is the H of 0.5～1mol/L ₂SO ₄, 0.5～1mol/L H ₃PO ₄, 1 ~ 3mol/L NaNO ₃Or the KOH aqueous solution of 0.5～1mol/L.

9. the preparation method of conducting polymer modified ultracapacitor according to claim 5; It is characterized in that; Step 5 at the concrete grammar of metal electrode layer surface deposition conducting polymer thin film is: at first that ferric trichloride or p-methyl benzenesulfonic acid ferroxidant, stearic acid secondary film formers, chloroform solvent is even by 2: 1: 10 mixed, with micro syringe mixed liquor is sprawled on parfacies (deionized water) then; Adopt czochralski process then, obtain the oxidant film of one deck tens to the hundreds of nanometer thickness at the metal electrode laminar surface; At last the oxidant film is immersed in aniline monomer, pyrrole monomer or the thiophene monomer, takes out oven dry after 30 minutes, and clean with alcohol flushing, just on metal electrode, obtain one deck conducting polymer thin film.

Images