CN106033695A - Asymmetric super-capacitor and preparation method for the same - Google Patents

Abstract

The invention relates to an asymmetric super-capacitor and a preparation method for the same. The preparation method comprises steps of (1) electrolytically depositing Ni,Co, and S on graphene foam to prepare Ni-Co-S/ graphene foam as an anode material, (2) preparing graphene gel as a cathode material, (3) determining a mass ratio of the anode material and the cathode material is 0.2-0.4, and (4) using a polypropylene diaphragm between the anode material and the cathode material to immerse in a 1M KOH solution to assemble an asymmetric super-capacitor. Compared with the prior art, the preparation technology is simple, the obtained asymmetric super-capacitor has very high electrochemistry capacitance performance, has excellent energy storage performance and has very high function density, power density and circulation stability.

Description

A kind of Asymmetric Supercapacitor and preparation method thereof

Technical field

The present invention relates to a kind of Asymmetric Supercapacitor and preparation method thereof, belong to supercapacitor technologies field.

Background technology

Ultracapacitor is a kind of novel energy-storing device occurred in recent years, and ultracapacitor is also called electrochemistry electricity Container, is the model electrochemical energy storage device between traditional capacitor and battery, has higher than rechargeable battery Power density, the energy density characteristics higher than traditional capacitor.Additionally, ultracapacitor also has environment without dirt Contaminate, have extended cycle life, use temperature range width, security performance high, thus occupy in new energy technology The critical role (Chinese SciBull, 2011,56:2092-2097) day by day manifested.But current ultracapacitor Development bottleneck be its relatively low energy density.Graphene is the new carbon received much concern in recent years, because it is only Special structural behaviour and in terms of electrode material for super capacitor, obtain application, Co, Ni, S are at super electricity simultaneously In container, performance is outstanding, with low cost, is also widely used.

In recent years, in multiple substrate, grow cobalt sulfur, nickel sulfur or nickel cobalt sulfur compound by multiple means, but many Number step is more, and process is loaded down with trivial details, is not easy to industrialized production.

Summary of the invention

Defect that the purpose of the present invention is contemplated to overcome above-mentioned prior art to exist and provide one to have high electrification Learn Asymmetric Supercapacitor of capacitive property and preparation method thereof.

The purpose of the present invention can be achieved through the following technical solutions:

A kind of Asymmetric Supercapacitor, is electrochemically-deposited on grapheme foam with Ni, Co, S, obtains Ni-Co-S/ grapheme foam, using Ni-Co-S/ grapheme foam as positive electrode, using Graphene gel as negative Pole material.

With polypropylene diaphragm between positive electrode and negative material, it is immersed in 1M KOH solution, is assembled into non- Symmetrical ultracapacitor.

According to positive electrode and the electric property of negative material, in order to realize high chemical property, positive and negative electrode electricity Lotus balances should follow following formula:

q⁺=q^-

And the ratio electric capacity C of quantity of electric charge q and positive and negative pole material, difference Δ V is relevant with quality m for work potential:

Q=C × Δ V × m

Therefore, the optimum quality ratio of positive and negative pole material such as following formula can be calculated:

$\frac{m_{+}}{m_{-}}=\frac{C_{-}\×\mathrm{\Δ}{V}_{-}}{C_{+}\×\mathrm{\Δ}{V}_{+}}$

In the present invention, described positive electrode and the quality of negative material can be between 0.2-0.4 than the range of choice.

As preferably, described positive electrode is 0.28 with the mass ratio of negative material.

The preparation method of a kind of Asymmetric Supercapacitor, comprises the following steps:

(1) at grapheme foam substrates Ni, Co, S, Ni-Co-S/ grapheme foam is prepared, as just Pole material；

(2) Graphene gel is prepared, using Graphene gel as negative material；

(3) determine that positive electrode is 0.2-0.4 with the mass ratio of negative material, between positive electrode and negative material With polypropylene diaphragm, it is immersed in 1M KOH solution, is assembled into Asymmetric Supercapacitor.

In step (1), preparation Ni-Co-S/ grapheme foam comprises the following steps:

With CoCl₂·6H₂O、NiCl₂·6H2O、CS(NH₂)₂Mixed solution is raw material, in three-electrode system, Using grapheme foam as working electrode, Pt line is as to electrode, and SCE is as reference electrode, cyclic voltammetry Sweep speed 10mv s^-1, voltage-0.9～0.2V, circulation 40 circle, in grapheme foam substrates Ni-Co-S nanometer Sheet, obtaining product is Ni-Co-S/ grapheme foam, is abbreviated as Ni-Co-S/GF.

Described CoCl₂·6H₂O、NiCl₂·6H2O、CS(NH₂)₂Mol ratio be 2:1:300, be preferably 5mM CoCl₂·6H₂O、2.5mM NiCl₂·6H2O、0.75M CS(NH₂)₂Mixed solution.

In step (2), preparation Graphene gel method is: by the graphene aqueous solution sonic oscillation 1 of 2mg/ml After hour, it is placed in autoclave sealing, hydro-thermal method 180 DEG C heating 12h, then above-mentioned product freezing is done Dry method is dried 12h, is then vacuum dried 6h, obtains Graphene gel.

Described grapheme foam is prepared by the Ni-based chemical vapour deposition technique of foam, for 3D network structure, with tradition Grapheme material compare, there is the motion of higher specific surface area and electric conductivity, more conducively conductive ion, be one Individual ideal collector.

The Asymmetric Supercapacitor that the present invention is prepared carry out electric performance test use following methods:

In chi660d electrochemical workstation, just carrying out in 1M KOH solution initially with three-electrode system Pole and the electro-chemical test of negative material.When surveying positive electrode, Ni-Co-S/GF as working electrode, Pt line and Saturated calomel electrode is respectively as auxiliary electrode and reference electrode.Survey negative material time, Graphene gel directly as Working electrode, auxiliary electrode and reference electrode are ibid.Asymmetric super capacitor performance uses two electrode systems to survey Examination.

Compared with prior art, preparation technology of the present invention is simple, by electrochemical deposition, heavy on grapheme foam Long-pending Ni-Co-S complex a, it is only necessary to step just can complete, simple to operate, is very beneficial for following large-scale raw Produce and application.Above-mentioned product, as positive electrode, has the most superior chemical property.Negative material choosing simultaneously By Graphene gel, it is assembled into asymmetric capacitor, can effectively widen the potential window of capacitor, improve super The energy density of capacitor.Electrochemical property test shows, the Asymmetric Supercapacitor of the present invention has the highest Electrochemical capacitor performance, there is outstanding energy-storage property, there is the highest energy force density, power density And cyclical stability.

Accompanying drawing explanation

Fig. 1 a, 1b are Ni-Co-S/GF field emission scanning electron microscope figure；

Fig. 2 a, 2b are Ni-Co-S/GF transmission electron microscope picture；

Fig. 3 is Ni-Co-S/GF cyclic voltammetry curve under difference sweeps speed；

Fig. 4 a, 4b are Ni-Co-S/GF charging and discharging curve under different current intensity；

Fig. 5 is Ni-Co-S/GF ratio capacitance under different electric current densities；

Fig. 6 is that Ni-Co-S/GF is at 20A g^-1Cycle life figure；

Fig. 7 is Asymmetric Supercapacitor cyclic voltammetry curve under difference sweeps speed；

Fig. 8 a, 8b are Asymmetric Supercapacitor charging and discharging curve under different current intensity；

Fig. 9 is that Asymmetric Supercapacitor is at the ratio capacitance under different electric current densities；

Figure 10 is Asymmetric Supercapacitor cycle life figure；

Figure 11 is that Asymmetric Supercapacitor is at energy density, power density curve.

Detailed description of the invention

The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.

Embodiment

Preparation 5mM CoCl₂·6H₂O、2.5mM NiCl₂·6H2O、0.75M CS(NH₂)₂Mixed solution, And in three-electrode system, grapheme foam is as working electrode, and Pt line is as to electrode, and SCE is as reference Electrode, cyclic voltammetry sweeps speed 10mv s^-1, voltage-0.9～0.2V, circulation 40 circle deposit N i-Co-S nanometer Sheet, obtaining product is Ni-Co-S/GF.

Products therefrom Ni-Co-S/GF pattern and structure are as shown in Fig. 1 a, 1b, Fig. 2 a, 2b, and Fig. 1 a shows It it is the low power electron scanning Electronic Speculum SEM figure that grown Ni-Co-S complex on grapheme foam stephanoporate framework； Fig. 1 b display high power Ni-Co-S complex SEM figure, it is seen that Ni-Co-S nanometer sheet vertically grows and is cross-linked with each other, Form the structure of a kind of porous.Fig. 2 a, 2b are shown that Ni-Co-S nanometer sheet TEM figure, further illustrate Ni-Co-S complex is a kind of loose structure, consistent with Fig. 1 b (SEM figure).

Above-mentioned Ni-Co-S/GF carries out electrochemical property test, and cyclic voltammetry CV figure is as it is shown on figure 3, can See that it has obvious oxidoreduction peak, be classical Faradic electricity container.

Products therefrom Ni-Co-S/GF constant current charge-discharge is as shown in Fig. 4 a, 4b, at 1A g^-1Time, higher than electric capacity Reach 1642F g^-1。

Even if products therefrom Ni-Co-S/GF under different electric currents than capacitance size as it is shown in figure 5, at big electric current 50 A g^-1Time, still it is up to 869F g than electric capacity^-1.It is at 20A g^-1Under, cyclical stability as shown in Figure 6, follows 90% is reached than capacity retention after ring 1,000 times.

After the graphene aqueous solution sonic oscillation 1 hour of 2mg/ml, it is placed in autoclave sealing, hydro-thermal Method 180 DEG C heating 12h, is then dried 12h by above-mentioned product freeze-drying, is then vacuum dried 6h, To Graphene gel.

Using above-mentioned Ni-Co-S/GF as positive electrode, Graphene gel is as negative material, and positive electrode is with negative The mass ratio of pole material is 0.28, with polypropylene diaphragm between positive electrode and negative material, is immersed in 1M KOH In solution, it is assembled into Asymmetric Supercapacitor.

To the present embodiment prepare Asymmetric Supercapacitor carry out electric performance test use following methods:

In chi660d electrochemical workstation, just carrying out in 1M KOH solution initially with three-electrode system Pole and the electro-chemical test of negative material.When surveying positive electrode, Ni-Co-S/GF as working electrode, Pt line and Saturated calomel electrode is respectively as auxiliary electrode and reference electrode.Survey negative material time, Graphene gel directly as Working electrode, auxiliary electrode and reference electrode are ibid.Asymmetric super capacitor performance uses two electrode systems to survey Examination.

The Asymmetric Supercapacitor that the present embodiment prepares, its cyclic voltammetry CV figure is as it is shown in fig. 7, electrochemical window Mouth reaches 1.6V.Constant current charge-discharge is as shown in Fig. 8 a, 8b, at 0.5A g^-1Time, it is up to 152F g than electric capacity^-1。 Its under different electric currents than capacitance size more as shown in Figure 9, it is seen that there is good high rate performance.Its cyclical stability Such as Figure 10, circulating 10000 times, the most do not decay, stability is remarkable.Its energy density and power density Relation is as shown in figure 11.It is 0.4kW kg in power density^-1Time, energy density is 54Wh kg^-1, at energy Density is 16kW kg^-1Time, energy density is 20Wh kg^-1。

Therefore, Asymmetric Supercapacitor prepared by the present embodiment has the highest electrochemical capacitor performance, has Outstanding energy-storage property, has the highest energy force density, power density and cyclical stability.

The above-mentioned description to embodiment is to be understood that for ease of those skilled in the art and use to send out Bright.These embodiments obviously easily can be made various amendment by person skilled in the art, and at this The General Principle illustrated is applied in other embodiments without through performing creative labour.Therefore, the present invention does not limits In above-described embodiment, those skilled in the art are according to the announcement of the present invention, without departing from changing that scope is made Entering and revise all should be within protection scope of the present invention.

Claims (8)

1. an Asymmetric Supercapacitor, it is characterised in that be electrochemically-deposited in Graphene with Ni, Co, S On foam, obtain Ni-Co-S/ grapheme foam, using Ni-Co-S/ grapheme foam as positive electrode, with graphite Alkene gel is as negative material.

A kind of Asymmetric Supercapacitor the most according to claim 1, it is characterised in that at positive electrode And with polypropylene diaphragm between negative material, it is immersed in 1M KOH solution, is assembled into Asymmetric Supercapacitor.

A kind of Asymmetric Supercapacitor the most according to claim 1, it is characterised in that described positive pole Material is 0.2-0.4 with the mass ratio of negative material.

A kind of Asymmetric Supercapacitor the most according to claim 3, it is characterised in that described positive pole Material is 0.28 with the mass ratio of negative material.

5. the preparation method of an Asymmetric Supercapacitor as claimed in claim 1, it is characterised in that bag Include following steps:

(1) at grapheme foam substrates Ni, Co, S, Ni-Co-S/ grapheme foam is prepared, as just Pole material；

(2) Graphene gel is prepared, using Graphene gel as negative material；

(3) determine that positive electrode is 0.2-0.4 with the mass ratio of negative material, between positive electrode and negative material With polypropylene diaphragm, it is immersed in 1M KOH solution, is assembled into Asymmetric Supercapacitor.

The preparation method of a kind of Asymmetric Supercapacitor the most according to claim 5, it is characterised in that In step (1), preparation Ni-Co-S/ grapheme foam comprises the following steps:

With CoCl₂·6H₂O、NiCl₂·6H2O、CS(NH₂)₂Mixed solution is raw material, in three-electrode system, Using grapheme foam as working electrode, Pt line is as to electrode, and SCE is as reference electrode, cyclic voltammetry Sweep speed 10mv s^-1, voltage-0.9～0.2V, circulation 40 circle, in grapheme foam substrates Ni-Co-S nanometer Sheet, obtaining product is Ni-Co-S/ grapheme foam.

The preparation method of a kind of Asymmetric Supercapacitor the most according to claim 6, it is characterised in that Described CoCl₂·6H₂O、NiCl₂·6H2O、CS(NH₂)₂Mol ratio be 2:1:300.

The preparation method of a kind of Asymmetric Supercapacitor the most according to claim 5, it is characterised in that In step (2), preparation Graphene gel method is:

After the graphene aqueous solution sonic oscillation 1 hour of 2mg/ml, it is placed in autoclave sealing, hydro-thermal Method 180 DEG C heating 12h, is then dried 12h by above-mentioned product freeze-drying, is then vacuum dried 6h, To Graphene gel.