CN101916664B

CN101916664B - Hybrid micro-supercapacitor based on organic electrolyte and manufacturing method thereof

Info

Publication number: CN101916664B
Application number: CN2010102436411A
Authority: CN
Inventors: 王晓峰; 尤政
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2010-08-03
Filing date: 2010-08-03
Publication date: 2012-02-08
Anticipated expiration: 2030-08-03
Also published as: CN101916664A

Abstract

The invention discloses a hybrid minitype super capacitor and a manufacturing method thereof, and belongs to the technical field of MEMS. The minitype super capacitor is composed of a support body, a positive electrode, an isolated body, a negative electrode and aluminum seal covers, wherein the minitype super capacitor is in a coiling structure; the positive electrode, the isolated body and the negative electrode are soaked in a lithium perchlorate organic electrolyte; the positive electrode comprises an active carbon energy storage material, an acetylene black conducting material and polyvinylidene fluoride adhesive, and is prepared by a screen printing method; the negative electrode comprises a lithium titanate energy storage material, acetylene black and polyvinylidene fluoride adhesive, and is prepared by the screen printing method; the isolated body is a copolymer in a polyvinylidene fluoride-hexafluoropropylene porous structure and is prepared by a spin coating method; and the ends of the positive electrode and the negative electrode are respectively provided with the aluminum seal cover prepared by a magnetron sputtering method, and the aluminum seal covers are used as electrode terminals to perform the function of a current collector. The large contact area of the aluminum seal covers and the electrodes can effectively reduce the resistance of the minitype super capacitor, thereby enhancing the energy storage characteristic of the minitype super capacitor; and the invention can increase the voltage of the minitype super capacitor to 3.6 V.

Description

Hybrid micro super capacitor and manufacturing approach thereof based on organic electrolyte

Technical field

The invention belongs to the MEMS technical field, particularly a kind of hybrid micro super capacitor and manufacturing approach thereof based on organic electrolyte.

Background technology

Miniaturization of electronic products, microminiaturization, integrated be the trend of the times of world today's technical development.Microelectromechanical systems (Micro Electro Mechanical Systems is called for short MEMS) has mobility, automatic control property, characteristics such as integrated, is one of most important technological innovation in recent years.When a sub-systems can be integrated on the chip piece, power supply also must be accomplished the revolution of miniaturization, microminiaturization.The MEMS micro-energy resource system is meant the technology based on MEMS; It is that micron order, overall dimension are the micro-system of Centimeter Level that one or more electric energy feedwaies are integrated into a characteristic size; Can realize long-time, high-effect, multi-mode power supply, be specially adapted to some particular surroundings that conventional power source can't be used.The miniature energy of excellent performance is to the development of MEMS system and improve and just have special meaning.At present the patent in external this field mainly concentrates on fields such as miniature lithium ion battery, miniature zinc aluminum cell, like the patent (US.6610440BS) of the relevant miniature zinc aluminum cell of the patent (US.5567210) of the relevant miniature lithium ion battery of U.S. oak ridge National Laboratory and U.S. Bipolar technologies company.Preparation method in the involved little energy device of above-mentioned related patent U.S. Patent No. technology is through the small electrode of prepared in various methods yardstick; Receive the restriction of factors such as electrode area is limited; Indexs such as the internal resistance of prepared miniature energy device, capacity can not satisfy device requirement, have seriously restricted the application of miniature energy device.Compare with minicell, micro super capacitor requires to have lower internal resistance to satisfy its instantaneous high power discharge ability.And up to the present,, effective solution is not proposed as yet to the internal resistance that how effectively to reduce micro super capacitor.In addition, be no more than 2.7V based on the micro super capacitor cell operation voltage of organic electrolyte and same structure activated carbon positive and negative electrode, up to the present, the cell operation voltage to how improving micro super capacitor does not propose effective solution yet.

Summary of the invention

The objective of the invention is to provide a kind of hybrid micro super capacitor of organic electrolyte, it is characterized in that, the structure of this micro super capacitor is on a slice polyimides supporter, to be arranged in order positive pole, slider, negative pole; In positive pole, slider, negative pole, flooded organic electrolyte; On combination surface, cover identical a slice polyimides supporter again and form a capacitor unit; Interconnecting the back with the polyimides supporter of a plurality of capacitor units reels and becomes the coin structure; In coin shape structure both sides is that a proper utmost point, the other end are negative pole, is tightly connected by the aluminium capping respectively, and the aluminium capping plays collector as electrode terminal simultaneously; The aluminium capping contacts with the large tracts of land of negative pole with anodal, effectively reduces micro super capacitor resistance.

Comprise energy storage material, electric conducting material acetylene black and adhesive Kynoar in said positive pole and the negative pole respectively; Anodal and negative pole adopts different materials to form composite super capacitor can be increased to 3.6V with cell voltage.

Said anodal energy storage material is an activated carbon, and electric conducting material is an acetylene black, and adhesive is a Kynoar, and adds the 1-methyl pyrrolidone, presses ratio of quality and the number of copies 7: 2: 1: 30 fully stir the slurry that the back forms good fluidity.

Said negative pole comprises that energy storage material is lithium titanate Li ₄Ti ₅O ₁₂, electric conducting material is an acetylene black, adhesive is a Kynoar, and adds the slurry that the 1-methyl pyrrolidone fully stirs back formation good fluidity; Lithium titanate, acetylene black, Kynoar and 1-methyl pyrrolidone ratio of quality and the number of copies are 7: 2: 1: 30, fully stir the slurry that the back forms good fluidity.

Said slider is a loose structure, and its composition is a Kynoar PVDF-hexafluoropropylene PHFP copolymer.Flooded organic electrolyte in said positive pole, negative pole and the slider, electrolyte solute composition is lithium perchlorate LiClO ₄, solvent composition is ethylene carbonate EC and carbonic acid diethyl ester DEC mixed liquor, the ratio of quality and the number of copies of EC and DEC is 1: 2; Add lithium perchlorate LiClO ₄In solvent, being configured to concentration is the organic electrolysis liquor of 1mol/L.

A kind of manufacturing approach of hybrid micro super capacitor of organic electrolyte is characterized in that, at first the slurry of positive pole and negative pole energy storage material adopts silk screen print method to be prepared in polyimide-based surface; Form positive pole and negative pole array, between positive pole and negative pole, coat slider, the dipping organic electrolyte; With the polyimide matrix surface that is incumbent on; Adopt the method that cuts that said structure is partitioned into unit one by one then, positive pole and negative pole are divided into equal two parts respectively in the cutting process, and belong to different units respectively; Be formed between two polyimides supporters; Arrange by positive pole, slider and negative pole, each unit connects and reels by equidirectional becomes the coin structure, and coin shape structure both sides deposition of aluminum capsule is to accomplish capacitor package.The aluminium capsule contacts as contact conductor with anodal, negative pole respectively, to reduce the micro super capacitor internal resistance.

The invention has the beneficial effects as follows that anodal and negative pole adopt different materials to form composite super capacitor and can cell voltage be increased to 3.6V to overcome in the correlation technique micro super capacitor internal resistance higher; Cell operation voltage is on the low side, can't satisfy the defective of device energy storage requirement.Can reduce the micro super capacitor internal resistance, and then reach the effect of improving the micro super capacitor energy storage characteristic.

Description of drawings

Fig. 1 is based on the hybrid micro super capacitor of organic electrolyte and forms structural representation.

Fig. 2 is based on the hybrid micro super capacitor schematic diagram of fabrication technology of organic electrolyte.

Embodiment

The present invention provides a kind of hybrid micro super capacitor and manufacturing approach thereof based on organic electrolyte.Below with reference to accompanying drawing and combine embodiment to specify the present invention.

Fig. 1 is based on the hybrid micro super capacitor of organic electrolyte and forms structural representation.Micro super capacitor is arranged positive pole 2, slider 4 and negative pole 3 by between two polyimide matrixes 1 by vertical direction from top to bottom, forms a unit; A plurality of unit interconnect and are wound into cylinder; Aluminium capping 5 is covered respectively at the cylinder two ends; Flooded organic electrolyte in above-mentioned anodal 2, negative pole 3 and the slider 4, anodal 2, negative pole 3 is drawn from two ends respectively, plays the effect of collector simultaneously as electrode terminal; Contact with anodal 2 and the effective of negative pole 3 through large-area aluminium capping 5; Thereby reduced the micro super capacitor internal resistance, adopt different energy storage materials through anodal 2 respectively with negative pole 3, thereby the cell operation voltage of micro super capacitor has been brought up to 3.6V; And then improved energy storage characteristic based on the said structure micro super capacitor.The aluminium capping contacts with the large tracts of land of electrode can effectively reduce micro super capacitor resistance.

Fig. 2 is based on the hybrid micro super capacitor schematic diagram of fabrication technology of organic electrolyte.Electrode manufacturing process of the present invention, it mainly comprises the silk screen print method preparation of 1 positive pole of polyimide matrix and negative pole array, what electrode gap exsomatized coats the covering of upper strata polyimide matrix; The assembly slitting of polyimide matrix, positive pole, negative pole array and upper strata polyimide matrix becomes unit 11, between two sheet matrixes 1, comprises positive pole 2, slider 4 and negative pole 3 this moment in the unit 11.Reel and become coin structure 12 in unit 11.Coin structure both sides deposition of aluminum capping 5.The encapsulation of completion micro super capacitor.

The preparation of the silk screen print method of polyimide matrix surface electrode array comprises the choosing of positive pole and negative pole energy storage material, the preparation of electrode slurry and the silk screen print method preparation of electrod-array.

Anodal energy storage material is an activated carbon, and the activated carbon with characteristics such as high-specific surface area and low impurity contents can be elected to be negative material, and its specific area should be greater than 1500m ²/ g, carbon content in the material (mass ratio) should be higher than 98%, the YP-15 type activated carbon that typical case's representative as Japanese Kuraray company (kuraray) produce.The anode sizing agent preparation method is for admixture partially conductive material and adhesive in above-mentioned anodal energy storage material and add the slurry that the 1-methyl pyrrolidone fully stirs back formation good fluidity.Conductive material is an acetylene black.Adhesive is a Kynoar.The anode sizing agent composition is activated carbon, acetylene black, Kynoar, 1-methyl pyrrolidone, and its best in quality ratio is 8: 1: 1: 30.Acetylene black is the key factor of restriction cathode performance, and acetylene black is very few in the anode sizing agent, and then prepared electrode internal resistance is big, and acetylene black is too much in the anode sizing agent, and then prepared pole strength is relatively poor.

The negative pole energy storage material is a lithium titanate, and its molecular formula is Li ₄Ti ₅O ₁₂The cathode size preparation method is for admixture partially conductive material and adhesive in above-mentioned negative pole energy storage material and add the slurry that the 1-methyl pyrrolidone fully stirs back formation good fluidity.Conductive material is an acetylene black.Adhesive is a Kynoar.The cathode size composition is lithium titanate, acetylene black, Kynoar, 1-methyl pyrrolidone, and its best in quality ratio is 7: 2: 1: 30.Acetylene black is the key factor of restriction negative pole performance, and acetylene black is very few in the anode sizing agent, and then prepared electrode activity is lower, and acetylene black is too much in the anode sizing agent, and then prepared pole strength is relatively poor.

The preparation method of electrod-array is based on above-mentioned electrode slurry, adopts method for printing screen, on large tracts of land polyimide matrix 1, prints anodal array and negative pole array, like Fig. 2 (a).Need after microelectrode array print to be accomplished in 80～150 ℃ of temperature ranges, preferred 120 ℃, vacuum drying 1 hour is with thorough removal 1-crassitude ketone solvent.Temperature is crossed to hang down and is prone to cause the removal of 1-methyl pyrrolidone not thorough, can influence capacitor performance.Temperature is too high to be prone to cause polyimide matrix to curl distortion.

Print anodal measure-alike with negative pole.500 microns-3000 microns of electrode widths, preferred 2000 microns.500 microns-1000 microns of electrode spacings, preferred 500 microns.200 microns-2000 microns of thickness of electrode, preferred 1000 microns.With additive method, method for printing screen can prepare thickness on matrix higher, the trickle clearly figure of figure.

The process of coating of porous polymer slider 4 is between electrode: with Kynoar-hexafluoropropylene copolymer (like Belgian SOLVAY Company products; Hexafluoropropylene content is 10%) be dissolved in the acetone fully dissolving, adopt then and get rid of the method that is coated with and be coated with and be formed between the electrod-array.Concrete grammar is that polyimide matrix is fixed on the photoresist spinner platform; On substrate, drip an amount of above-mentioned Kynoar-hexafluoropropylene copolymer acetone soln; The substrate rotating speed is evenly accelerated to necessarily than the slow-speed of revolution from static; Range of speeds 800-1200 rev/min, preferred 1000 rev/mins, and kept 10 seconds; Evenly accelerate to higher rotation speed then, range of speeds 1500-2000 rev/min, preferred 1800 change, and keep 25 seconds, evenly are decelerated to static then.Get rid of the substrate horizontal positioned 30 minutes in 25 ℃ of room temperature environments that is coated with completion, so that polymer oneself leveling and slowly discharge acetone solvent.Place it in thoroughly oven dry in 40 ℃ of vacuum drying ovens then.Acetone thoroughly removes back Kynoar-hexafluoropropylene copolymer and forms vesicular texture.

Kynoar-hexafluoropropylene slider gets rid of and is coated with the dipping that need carry out organic electrolyte after the completion, to be full of electrolyte in the pore space structure of guaranteeing electrode and slider.The electrolyte that the present invention adopted is the organic electrolysis liquor, and concentration is 1mol/L, and solute is lithium perchlorate LiClO ₄, solvent is ethylene carbonate EC and carbonic acid diethyl ester DEC mixed liquor (ratio of quality and the number of copies of EC and DEC is 1: 2 in the solvent).The electrolyte dipping process fully floods for the structure that will accomplish the preparation of electrode printing and slider is placed in the organic electrolyte, takes out the back and dries to remove unnecessary electrolyte.

After accomplishing, the electrolyte dipping above electrod-array, places one deck and the identical polyimide matrix 1 of matrix again, shown in Fig. 2 (c).The method that employing cuts is partitioned into several unit 11 with said structure, and shown in Fig. 2 (d), positive pole and negative pole are divided into two parts in the cutting process, and belong to different units respectively.In the unit 11, the sequence arrangement by positive pole 2, slider 4, negative pole 3 is arranged between two polyimide matrixes 1 at this moment; Be impregnated with electrolyte in positive pole 2, negative pole 3 and the slider 4, this moment anodal 2 and negative pole 3 lay respectively at the both sides up and down of coin structure and expose.A plurality of unit interconnect to reel becomes coin structure 12, coin structure both sides deposition of aluminum capping 5.The encapsulation of completion micro super capacitor is like Fig. 2 (e).

The magnetron sputtering technique process of aluminium capping is included in coin structure 12 both side surface magnetically controlled sputter methods and prepares aluminum metal layer completion encapsulation, like Fig. 2 (e).Aluminum metal layer is also born the function of electrode outside terminal when the performance sealing role is realized the micro super capacitor sealing, electric charge passes through aluminium capping 5 inflows or flows out electrode in the charge and discharge process.Magnetron sputtering aluminium capping technology can realize that electrode contacts with large tracts of land between the electrode terminal, has realized effective reduction of contact resistance between electrode and the aluminium capping, and then has reduced condenser resistance, improves the heavy-current discharge characteristic of capacitor.Magnetron sputtering technique can also be guaranteed effective sealing of micro super capacitor, has avoided ultracapacitor failure phenomenon in the course of the work.

The magnetron sputtering technique process of aluminium capping does; Coin structure 12 one sides upwards are fixed on the specimen holder of magnetron sputtering apparatus; Adopt aluminium (99.99%) as target; Under high-purity argon gas atmosphere, carry out sputtering technology, preparation aluminum metal layer thickness is greater than 10 microns, through prolonging the aluminum metal layer that the sputter reaction time can prepare higher thickness.The coin structure simultaneously deposits after the completion its upset, the deposition another side.Thickness is crossed to hang down and is prone to cause the electrode covering imperfect, is prone to cause electrolyte to reveal.The too high processing cost that then causes of thickness is too high.Can adopt plating or chemical plating method that capsule is further thickeied after deposition is accomplished, compare with magnetically controlled sputter method, magnetron sputtering combines processing cost much lower with plating or chemical plating method.

The present invention proposes a kind of hybrid micro super capacitor structure and manufacturing approach thereof; Can improve the capacitor unit operating voltage; Can reduce the capacitor internal resistance; And then improve the energy storage characteristic of micro super capacitor, be widely used in fields such as sensor network nodes power supply, fuze power supplies based on micro super capacitor described in the invention.

The above is merely the preferred embodiments of the present invention, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. A kind of hybrid micro-supercapacitor of organic electrolyte, it is characterized in that, the structure of this micro-supercapacitor is to arrange positive pole, separator, negative pole successively on a piece of polyimide support body; The organic electrolyte is impregnated, and the same piece of polyimide support is covered on the surface of the assembly to form a capacitor unit. The polyimide supports of multiple capacitor units are connected to each other and wound into a coin-shaped structure. On both sides of the coin-shaped structure is a positive electrode at one end and a negative electrode at the other end, which are respectively sealed and connected by aluminum covers. The aluminum covers also serve as electrode terminals and act as current collectors. Lower micro supercapacitor resistance.

2. The hybrid micro-supercapacitor of a kind of organic electrolyte according to claim 1, wherein, the positive pole and the negative pole respectively comprise energy storage material, conductive material acetylene black and binder polyvinylidene fluoride; The hybrid supercapacitor composed of different materials for positive and negative electrodes can increase the cell voltage to 3.6V.

3. The hybrid micro supercapacitor of a kind of organic electrolyte according to claim 1, is characterized in that, described anode energy storage material is activated carbon, conductive material is acetylene black, binder is polyvinylidene fluoride, And add 1-methylpyrrolidone, according to the ratio of parts by mass of 7:2:1:30, fully stir to form a slurry with good fluidity.

4. the hybrid micro-supercapacitor of a kind of organic electrolytic solution according to claim 1, is characterized in that, described negative electrode comprises energy storage material and is lithium titanate Li ₄ Ti ₅ O ₁₂ conductive material is acetylene black, bonding The agent is polyvinylidene fluoride, and 1-methylpyrrolidone is added to form a slurry with good fluidity after fully stirring; the ratio of mass parts of lithium titanate, acetylene black, polyvinylidene fluoride and 1-methylpyrrolidone is 7:2 : 1:30, a slurry with good fluidity is formed after fully stirring.

5. The hybrid micro-supercapacitor of a kind of organic electrolyte according to claim 1, characterized in that, the separator is a porous structure, and its composition is polyvinylidene fluoride PVDF-hexafluoropropylene PHFP copolymer.

6. the hybrid micro-supercapacitor of a kind of organic electrolytic solution according to claim 1, is characterized in that, impregnated organic electrolytic solution in described positive pole, negative pole and separator, and electrolytic solution solute composition is lithium perchlorate LiClO _4. The solvent component is a mixture of ethylene carbonate EC and diethyl carbonate DEC, and the mass-number ratio of EC and DEC is 1:2; add lithium perchlorate LiClO ₄ to the solvent, and configure it to be 1mol/L Organic electrolyte solution.

7. A method for manufacturing a hybrid micro-supercapacitor with an organic electrolyte, characterized in that first, the slurry of the positive and negative energy storage materials is prepared on the surface of the polyimide substrate by screen printing to form a positive and negative array , apply a separator between the positive electrode and the negative electrode, impregnate the organic electrolyte, cover the polyimide matrix on the upper surface, and then use the cutting method to divide the above structure into units one by one. During the cutting process, the positive electrode and the negative electrode They are divided into two equal parts and belong to different units respectively. They are formed between two polyimide supports and arranged according to the positive electrode, separator and negative electrode. Each unit is connected in the same direction and wound into a coin-like structure. Aluminum casings are deposited on both sides of the shape structure to complete the capacitor package, and the aluminum casings are respectively in contact with the positive and negative electrodes as electrode leads to reduce the internal resistance of the micro supercapacitor.

8. The manufacture method of the hybrid micro-supercapacitor of organic electrolyte according to claim 7, is characterized in that, the preparation of positive electrode and negative electrode array is with above-mentioned electrode paste, adopts screen printing method, on large-area polyamide The positive electrode array and the negative electrode array are printed on the imine substrate; after the positive electrode array and the negative electrode array are printed, they need to be dried in vacuum within the temperature range of 80-150°C for 1 hour to completely remove the 1-methylpyrrolidone solvent; the printed positive electrode The same size as the negative electrode, the electrode width is 500 microns-3000 microns, the electrode spacing is 500 microns-1000 microns, and the electrode thickness is 200 microns-2000 microns.

9. the manufacture method of the hybrid micro-supercapacitor of organic electrolyte according to claim 7, is characterized in that, the preparation of described spacer is that polyvinylidene fluoride-hexafluoropropylene copolymer is fully dissolved in acetone, Then it is coated between the electrode arrays by spin-coating method, and the spin-coated substrate is placed horizontally at room temperature at 25°C for 30 minutes, and then placed in a vacuum oven at 40°C to dry thoroughly to remove acetone and form pores. Polyvinylidene fluoride separator.

10. The manufacture method of the hybrid miniature supercapacitor of organic electrolyte according to claim 7, is characterized in that, described impregnating organic electrolyte is after spin-coating of polyvinylidene fluoride-hexafluoropropylene separator is finished organically. Electrolyte impregnation to ensure that the pore structure of the electrode and separator is filled with electrolyte; the electrolyte used is an organic electrolyte solution with a concentration of 1mol/L, the solute is lithium perchlorate LiClO ₄ , and the solvent is ethylene carbonate Grease EC and diethyl carbonate DEC mixture, the mass ratio of EC and DEC in the solvent is 1:2; the electrolyte impregnation process is to place the structure that has completed electrode printing and separator preparation in the organic electrolyte and fully impregnate it. Take it out and shake dry to remove excess electrolyte.