KR101858805B1 - Electrode including Nickel Oxide and Perforated Graphene For Supercapacitor and Manufacturing Method thereof - Google Patents

Abstract

The present invention aims to improve the performance of a super capacitor. In the case of an electrode made of NiO / GO, nickel oxide has an excellent electrostatic capacity, but the problem of the ions not reaching the nickel oxide due to the covered graphene is solved , And the perforated graphene and nickel oxide complex were used as an electrode material. In addition, there was an effect of adsorbing / storing electrolyte ions from the edges stretched by the punching of graphene.
That is, the present invention relates to an anode (anode) to which a NiO / PG composite in which nickel oxide (NiO) and perforated graphene (PG) are combined on a nickel foam (Ni-foam); And
And a cathode (cathode) to which graphene perforated on the nickel foam is attached,
Through the hole of the perforated graphene, the electrolyte ion easily access to the nickel oxide, and the effect of the adsorption / storage of the electrolyte ion at the edge and the electroconductivity of the nickel oxide are replaced by the perforated graphene, thereby improving the electrostatic capacity of the composite Thereby providing an asymmetric supercapacitor.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrode for a supercapacitor to which nickel oxide and perforated graphenes are applied, and a method of manufacturing the electrode.

The present invention relates to a structure of an electrode for a supercapacitor and a method of manufacturing the same.

In recent decades, the demand for portable, green energy has increased dramatically, and because of the capacity to hold larger power densities, fast charge / discharge rates, and high reliability, electrochemical supercapacitors (ESs) Which has a higher energy density (150-250 Wh / kg) than real ESs. If the energy density can be enhanced without lowering the output density of the ESs in any way, commercialization can be achieved. For the most part, ESs can be divided into two types according to their electronic storage schemes: electrical double layer capacitors, which depend on ion absorption and desorption, and pseudo capacitors that use fast surface redox reactions. Most electrical double layer capacitors utilize carbon-based materials for the double layer electrodes, which exhibit long-term stability, but unsatisfactory non-capacitance values (SC). Most of the pseudo-capacitors are composed of transition metal oxide, transition metal hydroxide, transition metal layered double hydroxide, etc. and used as electrode material. However, it has lower durability than the electric double layer capacitor series, but has a higher SC value.

Of the transition metal oxide materials, nickel oxide (NiO) has been used as a pseudo capacitor electrode due to its high theoretical capacitance, low charge generation, chemical and thermal stability, and environmental friendliness. However, since the output density is not high and the electric conductivity is poor, the value is much lower than the theoretical vestibular capacity.

In addition, nickel oxide has poor mechanical strength and low circulation stability, which is a serious obstacle to use as an electrode material for high performance ES devices. The combination of NiO and active materials such as polymer (polymer) or graphene has been proposed to compensate for weaknesses while taking advantage of NiO.

Graphene is a 2D material that has a large surface area and high electrical conductivity, is chemically stable, and has good mechanical strength among carbon-group elements. Cao et al. Reported an ES of 816 Fg- ¹ (scanning speed 5 mV s- ¹ ) using a NiO / graphene electrode, and Wu et al. Reported that 425 F g ^-1 SC (current density 2 A g ^-1 ) was obtained by growing NiO layer formed by oxidizing Ni-foam surface and graphene using Ni-foam itself as a catalyst . Jiang et al. Synthesized a composite of porous NiO and reduced graphene oxide to obtain a capacitance of 342.9 F g ^-1 at a current density of 1 A g ^-1 and a capacitance of 86.1% at over 2000 cycles. The SC values of the electrodes of the ESOs composed of NiO / graphene were mostly low, especially lower than that of the pure NiO electrode (the theoretical CS value was 2584 F g ^-1 within 0 to 0.5 V potential difference). In general, non-perforated graphene (NG) sheets block the access of electrolyte ions, as well as the pores of porous NiO nanostructures, reducing the direct contact of the electrolyte with the NiO surface, thereby reducing ion diffusion rate and diffusion .

It is an object of the present invention to make ESs having a high SC value, an excellent capacitance ratio and a long cycle life, and the present inventors have developed an electrode configuration system which improves the actual low capacitance of a metal oxide having a high theoretical capacitance I want to make it.

According to the above object, the present invention has designed / synthesized an electrode system composed of NiO having a theoretical fixed total capacitance and perforated graphene oxide (PG).

The electrode composed of the NiO / perforated graphene oxide (PG) according to the present invention forms a complex with the perforated graphene sheet and the NiO nanostructure as they grow, and the electrolyte solutions can easily reach the NiO surface through the holes of the graphene NiO particles are connected by graphene sheets between NiO particles that are not in contact with each other, and the low electrical conductivity of NiO replaces the graphene sheet, The capacity is greatly improved.

PG provides an access path for the electrolyte solution to reach the surface of the NiO and adsorbs / stores the electrolyte ions in the graphene holes and numerous edges (graphene defects) / NG < / RTI >

A chemical etching method was used to make the PG. Initially, PG electrodes along with NiO were specified in their structure, morphology, chemical state and surface area, and in later stages they were used for electrochemical measurements. The present inventors confirmed that the positive electrode and the negative electrode function as a PG electrode. Interestingly, the NiO / PG asymmetric supercapacitor (AS) device fabricated by combining a positive electrode composed of NiO / PG and a PG electrode as a negative electrode exhibited excellent performance and exhibited significant reversible cycling at a high potential of 1.6 V It showed, when the output density of 800 W kg ^-1 showed an energy density of 41.9 Wh kg ^-1 (8 high power density in the energy density in ^{kW kg -1 3.6 Wh kg -1)} , 4 a g -1 high discharge current and And perfect cycling stability (81.2% at over 10000 cycles).

The present inventors tested the performance of the AS element by turning on the red LED, and surprisingly, it showed the ability to maintain the ON state of the LED even after 600s. This shows the realistic potential of the present invention. In addition, the results obtained in the present invention were much better than previously reported NiO / hydroxide based AS device performance.

According to the present invention, a high surface area electrode composed of nickel oxide (NiO) / perforated graphene (PG) without the use of a binder is synthesized directly on the Ni foil by hot application, which results in a NiO / PG || PG of asymmetric supercapacitors Lt; RTI ID = 0.0 > anode < / RTI > For commercialization, it is important to develop AS devices that provide high non-electrostatic capacity and greater energy density and power density.

According to the present invention,

An anode (anode) to which a NiO / PG composite in which nickel oxide (NiO) and perforated graphene (PG) are combined on a substrate; And

And a cathode (cathode) to which graphene perforated on the nickel foam is attached,

The effect of the electrolyte ions on the surface of the nickel oxide through the hole of the perforated graphene, the effect of adsorbing and storing the electrolyte ions on the graphene edge formed by the perforation, and the low electrical conductivity of the nickel oxide by the perforated graphene, Wherein the asymmetric supercapacitor has improved chemical properties.

Further, according to the present invention,

The graphene oxide (GO) is diluted to make a suspension,

The concentrated nitric acid and the graphene oxide suspension were mixed, and the ultrasonic treatment was performed in parallel,

The mixture was centrifuged,

The obtained product obtained by centrifugation was subjected to dialysis to remove the acid to obtain perforated graphene (PG)

The perforated graphene was mixed with acetylene black, and a poly (tetrafluoroethylene) (PTFE) suspension binder to form a mixture,

Coating the mixture on a Ni foil, and drying the mixture.

Further, according to the present invention,

The graphene oxide (GO) is diluted to make a suspension,

The concentrated nitric acid and the graphene oxide suspension were mixed, and the ultrasonic treatment was performed in parallel,

The mixture was centrifuged,

The obtained product obtained by centrifugation was subjected to dialysis to remove the acid to obtain perforated graphene (PG)

The perforated graphene is placed in a solution containing the nickel precursor together with the Ni foil, treated by hot application,

The present invention also provides a method of manufacturing an anode for a super capacitor, characterized in that the Ni (OH) ₂ / PG composite obtained by the hot application method is annealed in an Ar atmosphere to obtain an NiO / PG composite electrode.

In the above, the solution containing the nickel precursor includes Ni (NO ₃ ) ₂ .6H ₂ O and hydrazine hydrate.

In the above, the hydrothermal treatment is carried out in an autoclave, and the nickel foam is placed vertically on the solution and maintained at 80 to 95 캜 for 4 to 6 hours.

In the above, the annealing is performed at 350 to 450 ° C for 30 minutes to 1 hour and 30 minutes.

According to the present invention, a nickel oxide having a large electrostatic capacity but a relatively low electrical conductivity and a graphene sheet having excellent electrical conductivity are formed into a sheet of perforated nickel oxide, It is possible to improve various electrochemical characteristics such as high capacitance, improvement of circulation stability, and high output density.

The AS devices fabricated with the NiO / PG electrodes according to the present invention exhibited higher non-volatile capacity (1,458 F g ^{- 1 at} current density of 3 A g ^-1 ) and perfect circulation stability (76.8% capacitances at over 5,000 cycles) showed a retention), the better energy density than the element (when the power density of ^{500 W kg -1 34.2 Wh kg -1} , a current density of 1 a g ^-1, F 246.5 g ^-1 in) made of NiO / NG electrode And output density (50.6 Wh kg ^-1 at 750 W kg ^-1 output density), highlighting the importance of PG in AS devices (using PG as the negative electrode), respectively.

The present inventors found that the defects existing at the pitted edge of PG kept the oxidation / reduction reaction rate of the metal oxide and electrolyte ions at the same level, and their electrochemical performance exceeded the planar graphene (NG) It is believed to have been acted as phosphorus storage (ultimately contributing to non-invasive capacity). In addition to electrochemical measurements of NiO / PG electrodes, surface morphology, structure, elemental analysis, surface area, etc. are initially tested to confirm the potential of the anode active material in supercapacitor applications. The AS element designed using NiO / PG (anode) and PG (cathode) electrode materials, ie NiO / PG / PG showed an energy density of 41.9 W h kg ^-1 at an output density of 800 W kg ^-1 , (82.1%), which were significantly stable. This is significantly better than the existing results.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing the production of NiO / PG of the present invention. FIG.
2 (a) and 2 (b) are FESEM and HRTEM images of NiO, (c) and (d) are NiO / PG images and the illustration is a SAED pattern.
3 (a) (B) XPS spectra of Ni 2p, (c) O 1s of NiO / PG, and (d) C 1s XPS spectra of NiO / PG and PG
FIG. 4 (a) is an N ₂ isotherm adsorption-desorption curve, and FIG. 4 (b) is a pore size distribution curve of NiO / PG.
5 (a) and 5 (b) are schematic diagrams of formation of NiO / NG and NiO / PG, and (c) and (d) FESEM images.
Figure 6 (a) shows CV and GCD (illustration), (b) shows SC vs. VCD . (C) equivalent circuit diagram and Nyquist plots, (d) NiO, NiO / PG and NiO / NG stability measurements.
Figure 7 (a) shows the results of the Nyquist measurement and simulation results of the cathode PG (measured at different scan speeds), (b) GCD (measured at different current densities) to be.
Figure 8 (a) shows CV (measured at different scan speeds), (b) GCD (for different current densities), (c) SC change vs. Current density, (d) circulation performance of NiO / PG / PG AS (e) Ragone plots, (f) related to energy density and power density associated with other results obtained from each reference number, It is a digital photograph which is turned on by connecting the battery in series and supplying electric power.
FIG. 9 is a photograph showing that the LED is connected to the supercapacitor of the present invention and sustained lighting for 600 seconds. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

material

Of concentrated hydrochloric acid (HCl, 37%), concentrated nitric acid (HNO _3, 70%) was obtained from vena chemistry.

Acetone and anhydrous ethanol solutions were obtained from SK Chemical. Other chemicals, nickel nitrate hexahydrate (> 97%, Ni (NO ₃ ) ₂ .6H ₂ O), potassium hydroxide (KOH), hexamethylenetetramine (HMT) Used as dignity and as received from Sigma Aldrich.

PG production

Graphene oxide was prepared by the modified Hummers method with graphite powder. In a typical reaction, H ₂ SO ₄ (180 mL) was added to a 2000-ml flask containing graphite (8 g) and sodium nitrate (4 g) at room temperature. Thereafter, solid KMnO ₄ (23 g) is slowly added while maintaining the temperature at 0 ° C (ice bath). After raising the temperature to 35 ° C, the mixture is agitated vigorously for 180 min. Then, 375 ml of distilled water is gradually added at 0 ° C, and the solution is stirred for 5 hours until the temperature is raised to 90 ° C. Finally, the solution was diluted with 1000 ml distilled water and treated with hydrogen peroxide water (H ₂ O ₂ , 30 wt.%) Until no more gas was produced. In this process, the color of the solution changed from dark brown to yellow. At this stage, the solution was filtered through a glass filter, the filtrate was washed with 5% HCl solution and then backwashed with distilled water. Then, the obtained GO is 0.1 w / v% was diluted to make a suspension, while the sonicated for 1h in a sealed 50ml vial was mixed with 70% concentrated HNO ₃ 39ml. The mixture was then placed in a 45-mL centrifuge tube, centrifuged 5 times and then dialyzed for 1 week to remove the acid by dialysis bag (molecular weight cut-off 2000 Da). The resulting product was diluted to make a 1 w / v % PG suspension.

Fabrication of PG cathode electrode

The above PG suspension was dried overnight under a vacuum of 60 DEG C to obtain PG powder. The PG electrode was synthesized through a one-pot solvothermal process. As a typical process, a dark brown solution was prepared by adding 60 mg of PG to 30 ml of water, and sonicated for 1 h in the latter stage. Thereafter, the mixture was transferred to a 50-ml Teflon line autoclave and heated to 180 ° C for 12 h. The synthesized PG is collected by centrifugation and drying at 50 < 0 > C overnight in a vacuum oven. The working electrode was obtained by mixing the active material with acetylene black and a poly (tetrafluoroethylene) (PTFE) suspension (60 wt.%) Binder in a mass ratio of 8: 1: 1 and applying the mixture on a Ni foil, Respectively. The electrode was dried overnight in a vacuum oven at 50 < 0 > C.

Fabrication of NiO / PG composite electrode

As shown in FIG. 1, NiO nanoparticles are grown on the Ni-foam in a mixture of a Ni precursor and PG, thereby forming a PG-coated NiO / PG composite electrode. In embodiments, the substrate may be Ni-foam, but may be another metal such as copper, and the shape may also be sheet metal or foam metal.

Prior to use, Ni foams (hole density 110 / inch, veneer density 320 g / m ² , 1 cm ㅧ 1 cm, Artenano Company Limited, Hong Kong) were pretreated through the following steps. First, a) dipped in acetone for 30 min to remove grease, b) etched with dilute HCl (3.0 mol / L) for 15 min, c) washed with deionized water, and d) dried.

After pre-treating the Ni-foam, a precursor for the growth of nickel hydroxide [Ni (OH) ₂ ] was prepared according to a previous report of the present inventors (Xia, Q .; Hui, KS; Hui, K. 2012, 69, 69-69 . Kim, Kwon, S .; Wang, Q .; Son, Y. A facile synthesis method of hierarchically porous NiO nanosheets. Mater. Lett. 71.).

First, 100 mmol of Ni (NO ₃ ) ₂ .6H ₂ O, 25 mmol of HMT, and 30 μL of hydrazine hydrate were dissolved in 50 mL of 1 w / v % PG suspension and homogenized by ultrasonication at room temperature for 30 min . The clean Ni-foam (2 cm x 4 cm) was placed vertically on a 50-mL solution stored in a Teflon-lined autoclave and maintained at 90 ° C for 5 hours. The reaction time and temperature may be from 70 to 95 < 0 > C for 3 to 6 hours. The Ni (OH) ₂ -Ni-foam substrate was rinsed with deionized water and ethanol to remove surface ions and molecules and vacuum dried at 50 ° C for 12 h. Next, the obtained Ni (OH) ₂ / PG composite was annealed in an Ar atmosphere at 400 ° C for 1 hour to form an NiO / PG composite electrode. The annealing may be performed at 300 to 500 DEG C for 30 minutes to 2 hours.

An electrode composed of NiO / perforated graphene oxide (PG) forms a complex of entangled graphene sheets and NiO nanostructures, and the electrolyte solution is easily accessible to the NiO surface through holes in the graphene , The graphene sheet connects NiO particles that are not in contact with each other, and the low electrical conductivity of NiO greatly improves the capacitance of the PG / NiO nanostructure by replacing the grafted sheet, which is attached to the graphene sheet, .

The mass of the NiO / PG composite electrode formed on the Ni-foam can be determined by subtracting the weight of the foam after the electrode deposition from the weight of the foam prior to deposition. The load density of the active materials was approximately 1.0 mg cm ^-2 for all electrodes. For comparison NiO electrodes and NiO / graphene (unetched graphene oxide [GO]) complexes were also pretreated using the same conditions.

Material property

The structure and phase were analyzed with an X-ray diffraction pattern (XRD, D8-Discovery Brucker, Cu Kα, 40 kV, 40 mA) and scanned in a 2θ range of 5 to 80 ^° with a 0.02 ^o step size. Field radial electron microscope (FESEM, Hitachi, S-4800, 15 kV) digital plane-view images were used to investigate surface morphologies. To determine the presence of PG beyond NiO, high resolution transmission electron microscopy (HRTEM) and electron diffraction digital images of selected regions were recorded using HRTEM Tecnai F20 unit at 200 kv. X-ray photo spectroscopy (XPS) measurements were performed using a surface analysis system (VG Scientifics ESCALAB250) using a monochromatic Al kα source (1486.6 eV), which sweeps the NiO / PG powder from the Ni-foam, The chemical bonding state of the electrodes was analyzed. XPS spectra were measured to show a carbon Ci peak at 284.6 eV.

Electrochemical measurement

Electrochemical tests were performed in a 1M KOH electrolyte solution at room temperature (25 ° C) using a three electrode electrochemical system. Platinum plates and mercury / mercury chloride were used as counter electrodes and reference electrodes, respectively. Cyclic voltammetry (CV) measurements and Galvano static charge-discharge (GCD) tests were performed on an Ivium-n-Stat electrochemical workstation (Ivium, Netherlands). The SC value of the electrode is calculated by the following formula (1).

(1) SC =

(One)

In the above, SC denotes F / g, I (mA) denotes discharge current; m (mg) is the mass, ΔV (V), and Δt (s) are the voltage drop and discharge charge / discharge times, and mass is the designated mass of active material.

AS Production

NiO / PG || PGAs were assembled to have NiO / PG and PG as positive and negative electrodes, respectively. A polypropylene cellulose paper separator (~ 16 μm) was used for the ion exchange of the electrolyte. According to the charge balance theory, the mass ratio of active materials (NiO / PG: PG) was estimated to be 1: 2.96. The coin cell packaging (CR2032) process was introduced during the assembly of AS devices. Electrolytes (1M KOH) were placed in each electrode cell and sealed in a coin cell at 80 kg / cm ² using a coin cell hydraulic sealing machine (Shenzhen Pengxiangyunda machinery, PX-HS-20). Was calculated from the GCD curve according to the SC equation (2) of the AS element.

(2) SC =

(2)

V (V) is the output change in the discharge time (IR drop), I (A) is the discharge current, Δt (s) is the discharge time, M (g) is the total mass of the active material, . The energy density (Wh Kg ^-1 ) and the output density (W Kg ^-1 ) of the NiO / PG / PG AS device were obtained from the GCD curve according to the following equation.

E = 0.5 × SC × Δ V 2 / 3.6 (3)

P = E / Δt (4)

E (Wh kg ^-1 ) is the energy density, Δ V (V) is the device voltage except IR drop, P (W kg ^-1 ) is the average power density and Δ t (s) is the discharge time.

Changes in surface morphology

To prepare NiO / PG on 3D Ni-foam, 70% concentrated HNO ₃ was added to the deionized water solution with stirring the GO suspension solution. The homogeneous mixture was subjected to ultrasonic dispersion treatment at room temperature for 1 hour. At sufficient sound pressure conditions, ultrasound creates high strain and frictional forces in cavitation bubbles that attack the carbonaceous surface and destroy the skeleton. The HNO ₃ present in the corner of the GO reacts with equally unsaturated carbon atoms in the damaged region and results in PG through partial separation and elimination of carbon atoms. The PG suspension, hydrazine hydrate and Ni ²⁺ precursors were homogeneously mixed to form a base material. For example, a Ni (OH) ₂ / PG electrode was synthesized by one-pot heat treatment at 90 ° C ambient temperature. The NiO / PG electrode was obtained by subjecting the electrode to an Ar-annealing process at 400 ° C. for 1 hour, which is illustrated in FIG.

2 (a) and 2 (b) are FESEM and HRTEM images of NiO, (c) and (d) are NiO / PG images and the illustration is a SAED pattern.

3 (a) (B) XPS spectra of Ni 2p, (c) O 1s of NiO / PG, and (d) C 1s XPS spectra of NiO / PG and PG

FIG. 4 (a) is an N ₂ isotherm adsorption-desorption curve, and FIG. 4 (b) is a pore size distribution curve of NiO / PG.

We have anticipated that NiO / PG can be an ideal electrochemical electrode material (see FIGS. 5 (a) and (b)) compared to NiO / NG, which once provided a shorter electrolyte ion diffusion path , b) assuring that the entire surface of the NiO nanosheets can be in contact with the electrolyte, c) providing an additional redox / storage location as the ions are efficiently adsorbed by the carbon defect at the PG hole edge, and d) In order to increase the electrochemical performance, the effect of the electric double layer capacitance and the pseudo capacitance characteristic can be seen. In addition, NiO / PG had a much higher chemical stability than NiO / NG, which can preserve high current density and enhance its durability. (B) the electrochemical performance was lowered due to the increase of the total mass (Fig. 5 (c)), because the electrolyte solutions and ions penetrated the NG and did not reach the surface of the metal oxide, . On the other hand, NiO / PG provided various pathways for efficient migration of electrolyte ions and showed improved electrochemical performance due to relatively small mass (FIG. 5 (d)).

6 (a) shows CV and GCD (illustration), and (b) shows SC vs. VCD . (C) equivalent circuit diagram and Nyquist plots, (d) NiO, NiO / PG and NiO / NG stability measurements.

Figure 7 (a) shows the results of the Nyquist measurement and simulation results of the cathode PG (measured at different scan speeds), (b) GCD (measured at different current densities) to be.

The NiO / PG composite electrode showed a maximum capacitance of 1,458 F g ^-1 at a current density of 3 A g ^-1 (SC values of NiO / NG and NiO were 1,171.2 F g ^-1 and 993.6 F g ^{-1, respectively} ) This is much higher than the previously reported NiO / graphene composite electrodes at the same current density. In addition, the NiO / PG electrode showed perfect high-speed performance, and when the current density increased from 3 to 20 A g ^-1 , the SC decreased by only 31.4%, highlighting the importance of high-speed SC electrode materials.

EIS analysis is mainly used to test the ion transport properties of electrode materials in supercapacitor devices.

The semicircular shape is related to the charge transfer resistance (R _ct ) due to the faradaic reaction. The diameters of the original semicircles of NiO, NiO / NG, and NiO / PG electrodes were 7.0, 3.6, and 2.8 Ω, indicating that better interfacial contact between NiO and PG contributed to efficient charge diffusion during the Faraday reaction it means. In the low frequency range, NiO / PG electrodes showed the most vertical Nyquist line results than NiO or NiO / PG electrodes, indicating that the electrode material exhibited the most ideal capacitive behavior, ie, rapid adsorption of ions, Because PG provided sufficient ion diffusion paths to allow the migration of ions with little force through the perforated holes.

Electrochemical properties of asymmetric supercapacitors

Due to the good electrochemical properties of the obtained NiO / PG used as anode material and PG used as cathode material, 1M KOH was used to fabricate the AS element of NiO / PG / PG composition. CV curves between 0 and 1.6 V of a full-cell NiO / PG / PG AS device can be seen in FIG. The presence of the redox peak indicates the paradoxpseudopacitive response of NiO / PG PG AS. FIG. 8B shows the GCD pattern of the NiO / PG / PG AS device under different current densities. When the current density of 1.0, 2.0, 3.0, 4.0, 5.0, and 10.0 g A ^-1 day NiO / PG PG || the AS _device element SC values are respectively 117.8, 72.3, 45.0, 33.5, 25.6, and 10.0 g F ^-1 It was (FIG. 8 c). GCD was used to determine the circulation performance of NiO / PG / PG AS.

As can be seen in FIG. 8D, NiO / PG | PG AS had significant cyclic stability and retained ~ 82% even at over 10000 cycles, surpassing previously reported NiO-based ASs 8 d ). In the form of an NiO / PG || energy density and the output density value PG of the AS device are calculated using the curve GCD And all Table (Ragone plot) in Figure 8 may e. At this time, when the output density was 800 W kg ^-1 , the energy density was 41.9 W h kg ^-1 . In addition, the highest energy density of 8,000 W kg ^-1 of the experiment was observed at a high current density of 4 A g ^{-1 with} an energy density of 3.6 W h kg ^-1 . These values are higher than the energy densities of the ASs based on the previously reported NiO, NiO / carbon, or Ni (OH) ₂ / carbon complexes. To demonstrate the practical application as possible, two NiO / PG / PG AS devices assembled on a laboratory scale were charged at a current density of 3 A g ^-1 , connected in series, and connected to a red light emitting diode for 10 s f ). To test the discharge level, we continued the operation of the diode for several hundreds of seconds, continued well until 600 s (Fig. 9), and then turned off, which is expected to be commercialized in the future.

It is to be understood that the invention is not limited to the disclosed embodiment, but is capable of many modifications and variations within the scope of the appended claims. It is self-evident.

No reference symbol.

Claims (6)

An anode (anode) to which a NiO / PG composite in which nickel oxide (NiO) and perforated graphene (PG) are combined on a substrate; And
And a cathode (cathode) to which graphene perforated on the nickel foam is attached,
The effect that the electrolyte ions easily approach the surface of the nickel oxide through the holes of the perforated graphene, the NiO particles which are not in contact with each other are connected by the perforated graphene, and the adsorption and storage of the electrolyte ions on the graphene edge formed by the perforation And an electrochemical characteristic is improved by complementing the low electrical conductivity of the nickel oxide instead of the perforated graphene. The graphene oxide (GO) is diluted to make a suspension,
The concentrated nitric acid and the graphene oxide suspension were mixed, and the ultrasonic treatment was performed in parallel,
The mixture was centrifuged,
The obtained product obtained by centrifugation was subjected to dialysis to remove the acid to obtain perforated graphene (PG)
The perforated graphene was mixed with acetylene black, and a poly (tetrafluoroethylene) (PTFE) suspension binder to form a mixture,
Wherein the mixture is coated on a Ni foil and dried to form a cathode. The graphene oxide (GO) is diluted to make a suspension,
The concentrated nitric acid and the graphene oxide suspension were mixed, and the ultrasonic treatment was performed in parallel,
The mixture was centrifuged,
The obtained product obtained by centrifugation was subjected to dialysis to remove the acid to obtain perforated graphene (PG)
The perforated graphene is placed in a solution containing the nickel precursor together with the Ni foil, treated by hot application,
Wherein the NiO / PG composite electrode is obtained by annealing the Ni (OH) ₂ / PG composite obtained by the hydrothermal method in an Ar atmosphere. The method for producing an anode for a super capacitor according to claim 3, wherein the solution containing the nickel precursor includes Ni (NO ₃ ) ₂ .6H ₂ O and hydrazine hydrate. 4. The method of claim 3, wherein the hydrothermal treatment is carried out in an autoclave, wherein the nickel foam is placed vertically on the solution and maintained at 80 to 95 DEG C for 4 to 6 hours. 4. The method according to claim 3, wherein the annealing is performed at 350 to 450 DEG C for 30 minutes to 1 hour and 30 minutes.

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