CN104064364A

CN104064364A - Preparation method of graphene for super capacitors for lead-carbon batteries

Info

Publication number: CN104064364A
Application number: CN201410269292.9A
Authority: CN
Inventors: 熊斌; 薛华
Original assignee: Shuangdeng Group Co Ltd
Current assignee: Shuangdeng Group Co Ltd
Priority date: 2014-06-17
Filing date: 2014-06-17
Publication date: 2014-09-24
Anticipated expiration: 2034-06-17
Also published as: CN104064364B

Abstract

The invention discloses a preparation method of graphene for super capacitors for lead-carbon batteries and belongs to the technical field of lead-acid storage battery manufacturing. The preparation method is characterized by comprising the steps of compounding a GO through a Hummers method, restoring the GO through hydrazine hydrate and ammonium hydroxide to prepare the graphene for the super capacitors, refining the graphene through centrifugal separation and vacuum filtration methods, and assembling graphene film obtained by filtration into symmetrical capacitors with specific capacitance reaching up to 395F/g. By adding the graphene for the super capacitors into negative electrode diachylon of the lead-carbon batteries, charge-discharge suffertibility of large current and cycle performance under part of states of charge of the batteries can be improved remarkably, sulfation of surfaces of electrodes is inhibited, and therefore, the batteries have high capacity and long cycle life.

Description

Be used for the preparation method of the electrochemical capacitance Graphene of lead carbon battery

Technical field

The preparation method who the present invention relates to a kind of electrochemical capacitance Graphene for lead carbon battery, belongs to lead acid accumulator manufacture technology field.

Background technology

The plurality of advantages such as lead-acid battery has that raw material sources extensively and is conveniently easy to get, cost is low, safe, stable performance and recoverable, are developed to today still in occupation of the considerable market share.Along with scientific and technological progress and development, every profession and trade has proposed new requirement to lead acid accumulator, and raising specific capacity and cycle life, reduction product weight are the problems of needing solution badly.Lead carbon battery is by add a certain amount of characteristic Carbon Materials in acid accumulator negative pole lead, utilize high conductivity and the capacitance characteristic of Carbon Materials, improve pole plate and accept the ability of instantaneous large-current, suppress polar board surface sulfation, improve active material utilization and discharge and recharge ability to accept, significantly having improved the cycle life of high magnification partial state of charge.

Lead carbon battery conventional charcoal additive have active carbon, carbon black, carbon nanofibers, graphite and carbon nano-tube etc.Desirable charcoal additive should have very high specific area and conductivity, brings into play its capacitance characteristic at charge and discharge process, buffering instantaneous large-current; Have concurrently with lead plaster affine good, dispersed high, and strong at electrochemical environment stability inferior simultaneously.Graphene is the carbon family two-dimensional material of rising recently, has numerous excellent specific properties, and specific area and conductivity are very high, and good stability is a kind of ideal charcoal additive.Graphene is the carbon monoatomic layer that adopts mechanical stripping method to strip down from graphite at first, and Graphene purity that the method obtains is high, defect is few, but its preparation condition harshness is difficult to realize mass production, and expensive.Laboratory adopts oxide-reduction method to prepare Graphene mostly, first with strong oxidizer by graphite oxidation, peel off graphite by chemical interactions, more graphite oxide reduction made to Graphene.But the oxy radical that oxidation reaction is introduced and in-plane defects are difficult to eliminate, its end product quality is difficult to control, and consistency is poor.The high-quality and the finished product consistency that how to realize Graphene are far reaching problems.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, provide a kind of and can improve the quality of Graphene and the preparation method of the conforming electrochemical capacitance Graphene for lead carbon battery of finished product.

The technical solution adopted in the present invention is as follows: a kind of preparation method of the electrochemical capacitance Graphene for lead carbon battery, it is characterized in that adopting Hummers method to synthesize GO, combine reduction GO by hydrazine hydrate and ammoniacal liquor, with the Methods For Purification of centrifugation and vacuum filtration, finally make electrochemical capacitance Graphene, above-mentioned GO refers to graphene oxide.

Further scheme is: the synthetic GO step of described Hummers method is: (1), approach 0 toward filling 150～200ml ^oin C ice strong sulfuric acid response device, once add 3.5～4.0g sodium nitrate and 4～6g expanded graphite, continuous stirring reaction 2.5～4h; (2), slowly add 20～25g potassium permanganate, control reactor temperature and be less than 20 ^oc, fully stirring reaction 10～14h; (3), add 400～800 ml 4～6 wt.% dilution heat of sulfuric acid stir 20～30 min, then add 40～60 g 30 wt.% hydrogen peroxide stir 30～45 min; (4), with excessive 30 wt.% sulfuric acid/1 wt.% mixed solution of hydrogen peroxide centrifuge washings, finally equal 7 with water centrifuge washing to supernatant liquor pH, obtain light yellow GO dispersion liquid.

Described hydrazine hydrate and ammoniacal liquor associating method of reducing are: get GO dispersion liquid, add successively a certain amount of ammoniacal liquor and hydrazine hydrate solution, under water bath with thermostatic control condition, reduce, hydrazine hydrate concentration is 35～45 wt.%, ammonia concn is 30～40 wt.%, and the quality proportioning of hydrazine hydrate and GO dispersion liquid is 1:100～140, quality proportioning 1:10～25 of ammoniacal liquor and GO dispersion liquid, bath temperature is 90～100 DEG C, and the water-bath time is 1～1.5h.

In described purification process, vacuum filtration pressure is 5～10kPa, and centrifugation rotating speed is 2000～10000r/min, and disengaging time is 5～10min.

The electrochemical capacitance Graphene quality of being prepared by technical scheme provided by the invention is high, and capacitive property is good, and manufacturing process is simple and easy, specification, controlled, is suitable for mass production.Test shows, the electrochemical capacitance Graphene making, for lead carbon battery, can significantly improve the cycle performance under battery high current charge-discharge suffertibility and partial state of charge, suppresses the sulfation of electrode surface, makes battery have high power capacity and long circulation life concurrently.

Brief description of the drawings

Fig. 1 is the transmission electron microscope picture of electrochemical capacitance Graphene;

Fig. 2 is the constant current charge-discharge curve with the symmetrical capacitor of graphene film composition.

Embodiment

Below in conjunction with accompanying drawing, the present invention is further described.

In the present embodiment, for the preparation method of the electrochemical capacitance Graphene of lead carbon battery, it is characterized in that adopting Hummers method to synthesize GO, combine reduction GO by hydrazine hydrate and ammoniacal liquor, and make electrochemical capacitance Graphene with the Methods For Purification of centrifugation and vacuum filtration.

The Hummers method of synthetic GO, synthesis step is: (1), approach 0 toward filling 175ml ^oin C ice strong sulfuric acid response device, once add 3.75g sodium nitrate and 5g expanded graphite, continuous stirring reaction 3h; (2), slowly add 22.5g potassium permanganate, control reactor temperature and be less than 20 ^oc, fully stirring reaction 12h; (3), add 500ml5wt.% dilution heat of sulfuric acid to stir 30min, then add 50g30 wt.% hydrogen peroxide to stir 30 min; (4), with 30wt.% sulfuric acid/1wt.% mixed solution of hydrogen peroxide centrifuge washing, finally with water centrifuge washing to supernatant liquor pH=7, obtain light yellow GO dispersion liquid.

Combine reduction GO with hydrazine hydrate and ammoniacal liquor, its operating procedure is: get the above-mentioned GO dispersion liquid making, add successively a certain amount of ammoniacal liquor and hydrazine hydrate solution, under water bath with thermostatic control condition, reduction makes Graphene.Hydrazine hydrate concentration is 40wt.%, and ammonia concn is 35wt.%, and the quality proportioning of hydrazine hydrate and GO is 1:120, the quality proportioning 1:20 of ammoniacal liquor and GO, and bath temperature is 90～100 ^oc, the water-bath time is 1h.The purification in later stage adopts centrifugation and vacuum filtration, and concrete operation step is as follows: (1), the mixed liquor after water-bath is left standstill, pour out supernatant liquor; (2), the pasty state settling down is added to pure water and equal 7 with the rotating speed of 6000r/min and the time centrifuge washing of 8min (being centrifugation) to washing lotion pH; (3), by vacuum filtration, Graphene is made to the film that thickness is about 2mm, vacuum filtration pressure is 5～10 kPa.

Gained Graphene, as the test specimens of transmission electron microscope, is dried content and the specific area of determination of moisture Graphene.Fig. 1 is the transmission electron microscope picture of Graphene, and the Graphene of combining reduction with hydrazine hydrate and ammoniacal liquor has obvious laminated structure, compound with regular structure, thickness homogeneous.By the nitrogen adsorption desorption curve of the Graphene sample after drying, calculating its specific area according to BET formula is 1169 m ²/ g.Infer thus, Graphene prepared by the method has 2～5 carbon atomic layers, and consistency is better.

The graphene film that suction filtration is made is assembled under atmospheric environment and is assembled into symmetrical capacitor, and collector is aluminium foil, and electrolyte is 6M potassium hydroxide solution.Fig. 2 is the symmetrical capacitor constant current charge-discharge figure being assembled by graphene film, and charging and discharging potential range is 0～1V, according to cs=4 i/ [(Δ u/ Δ t) m] calculate than electric capacity, under 0.1A/g current density its than electric capacity up to 395 F/g.

According to the Graphene content of drying moisture calculating, be that 1.5-3% adds Graphene in lead carbon battery cathode lead plaster to by quality proportioning, find by blank, battery specific capacity and the specific power of adding electrochemical capacitance Graphene are significantly improved, significantly strengthen the cycle performance under battery high current charge-discharge suffertibility and partial state of charge, be applicable to the field such as power and energy storage, have broad application prospects.

Claims

1. the preparation method for the electrochemical capacitance Graphene of lead carbon battery, it is characterized in that adopting Hummers method to synthesize GO, combine reduction GO by hydrazine hydrate and ammoniacal liquor, with the Methods For Purification of centrifugation and vacuum filtration, finally make electrochemical capacitance Graphene, above-mentioned GO refers to graphene oxide.

2. the preparation method of the electrochemical capacitance Graphene for lead carbon battery according to claim 1, is characterized in that the synthetic GO step of described Hummers method is: (1), approach 0 toward filling 150～200ml ^oin C ice strong sulfuric acid response device, once add 3.5～4.0g sodium nitrate and 4～6g expanded graphite, continuous stirring reaction 2.5～4h; (2), slowly add 20～25g potassium permanganate, control reactor temperature and be less than 20 ^oc, fully stirring reaction 10～14h; (3), add 400～800 ml 4～6 wt.% dilution heat of sulfuric acid stir 20～30 min, then add 40～60 g 30 wt.% hydrogen peroxide stir 30～45 min; (4), with excessive 30 wt.% sulfuric acid/1 wt.% mixed solution of hydrogen peroxide centrifuge washings, finally equal 7 with water centrifuge washing to supernatant liquor pH, obtain light yellow GO dispersion liquid.

3. the preparation method of the electrochemical capacitance Graphene for lead carbon battery according to claim 2, it is characterized in that described hydrazine hydrate and ammoniacal liquor associating method of reducing are: get GO dispersion liquid, add successively a certain amount of ammoniacal liquor and hydrazine hydrate solution, under water bath with thermostatic control condition, reduce, hydrazine hydrate concentration is 35～45 wt.%, ammonia concn is 30～40 wt.%, the quality proportioning of hydrazine hydrate and GO dispersion liquid is 1:100～140, quality proportioning 1:10～25 of ammoniacal liquor and GO dispersion liquid, bath temperature is 90～100 DEG C, and the water-bath time is 1～1.5h.

4. the preparation method of the electrochemical capacitance Graphene for lead carbon battery according to claim 1, it is characterized in that in described purification process, vacuum filtration pressure is 5～10 kPa, and centrifugation rotating speed is 2000～10000r/min, and disengaging time is 5～10min.