CN103022468B - Environment-friendly preparation method for high-specific-capacitance Mn3O4/graphene composite material for poles - Google Patents

Abstract

The invention discloses an environment-friendly preparation method for a high-specific-capacitance Mn3O4/graphene composite material for poles. According to the environment-friendly preparation method, graphite oxide produced from graphite and divalent manganese ions produced from potassium permanganate in a graphite oxidation process are directly used as precursors for producing a Mn3O4/graphene composite, the graphite oxide is not required for being separated, and a manganese source is not required for being additionally added, so that the technological process is simplified, and the cost is reduced; KOH is adopted as a precipitant, sulfuric acid in original waste liquid is transformed into a byproduct K2SO4, and the separated water can be recycled, so that the additional value of products is increased, and the cost is further reduced; and no pollutants and wastes are produced in the whole process, so that the method is beneficial to environment protection and suitable for large-scale production. The poles prepared from the material produced by the method have the specific surface area of 20-100 m<2>/g and the electrochemical capacity of 100-500 F/g.

Description

High specific capacitance Mn 3o 4the environment-friendly preparation method thereof of/graphene combination electrode material

Technical field

The present invention relates to a kind of high specific capacitance Mn ₃o ₄the preparation method of/graphene combination electrode material, especially a kind of technique is simple, with low cost, the high specific capacitance Mn that is beneficial to environmental protection, is applicable to large-scale production ₃o ₄the environment-friendly preparation method thereof of/graphene combination electrode material.

Background technology

Because there is the features such as the chemical property of abundance, cheap, environmental friendliness and excellence, Mn ₃o ₄be a kind of extensively concerned transition metal oxide, and be widely used in the electrode material of battery, but because of conductivity (~ 10 ^-7-10 ^-8s/cm) low and limit the performance of its capacitance, be a kind of effective ways giving full play to its chemical property with the material compound of high conductivity.

Graphene is the two-dimension single layer graphite be made up of carbon atom hexagonal structure (cellular) close-packed arrays, is the elementary cell of other dimension carbonaceous materials of structure.From 2004 by since Late Cambrian, cause the great interest of scientific circles immediately, about the basic research of Graphene and application study become the focus that every country in the world pays close attention to.Graphene has the performance of many excellences, as large specific area, good mechanical performance and chemical stability.Its maximum characteristic is that the speed that it at room temperature transmits electronics is all faster than known any conductor, and wherein the dynamic speed of electronics can reach 1/300 of the light velocity, greatly exceed the movement velocity of electronics in general conductor.In addition, it is also the material that in current known materials, electrical conductivity speed is the fastest, and the electronics under its room temperature moves speed can up to 15000 cm ²/ (V.s) (Y. B. Zhang, Y. W. Tan, H. L. Sto mer, nature 2005,438,201-204.).

Existing preparation Mn at present ₃o ₄the relevant report of/graphene complex, prepared Mn ₃o ₄/ graphene complex can be made into high specific capacitance electrode.But, existing preparation method first uses strong acid (as the concentrated sulfuric acid or perchloric acid) and strong oxidizer (as potassium permanganate) by graphite or expansible graphite oxidation, then obtain graphite oxide by centrifugal, washing, dry method, after graphite oxide mixes with manganous salt (as manganese chloride or manganese acetate) after a series of process, heat obtained Graphene/Mn again ₃o ₄compound.（H. L. Wang, L. F. Cui, Y. Yang, H. S. Casalongue, J. T. Robinson, Y. Y, Liang,Y. Cui, H. J. Dai, J. Am. Chem. Soc 2010, 132, 13978-13980. W. Qian, Z. Q. Chen, S. Cottingham, W. A. Merrill, N. A. Swartz, A. M. Gotorth, T. L. Clarec, J. Jiao, Green Chem 2012, 14, 371-377. L. Li, Z. P. Guo, A. J. Du, H. K. Liu. J. Mater. Chem . 2012, 22, 3600-3605.）。Give up the Mn preparing a large amount of acid remaining in graphite oxide process and potassium permanganate generation ²⁺and K ⁺, not only complex process, waste time and energy, and waste raw material, simultaneously discarded material causes serious pollution to environment again.

Summary of the invention

The present invention is the above-mentioned technical problem in order to solve existing for prior art, provides the high specific capacitance Mn that a kind of technique is simple, with low cost, be beneficial to environmental protection, be applicable to large-scale production ₃o ₄the environment-friendly preparation method thereof of/graphene combination electrode material.

Technical solution of the present invention is: a kind of high specific capacitance Mn ₃o ₄the environment-friendly preparation method thereof of/graphene combination electrode material, is characterized in that carrying out as follows successively:

A. being added to by graphite and filling concentration is in the beaker of 98% concentrated sulfuric acid, stirs 2 ~ 10 hours, slowly in beaker, add potassium permanganate under ice bath, continues to stir 2 ~ 10 hours under condition of ice bath; The beaker filling mixture is placed in 35 ~ 50 DEG C of water-baths 1 ~ 6 hour, more slowly adds distilled water wherein, after stirring, again bath temperature is risen to 98 DEG C, stir 1 ~ 4 hour; From water-bath, take out beaker, slowly add the warm water of 60 ~ 80 DEG C under stirring condition, stirring condition borehole cooling to 20 ~ 30 DEG C, in beaker, add the hydrogen peroxide that concentration is 30%, after stirring, obtain graphite oxide mother liquor; The amount ratio of described reactant is graphite: the concentrated sulfuric acid: potassium permanganate: hydrogen peroxide: distilled water: warm water=1g:16.3 ~ 32.6ml:3 ~ 8:1 ~ 5ml:30 ~ 100ml:100 ~ 200ml;

B. under the condition constantly stirring and blast air, in graphite oxide mother liquor prepared by a step, dropwise add KOH solution reach 10 ~ 13 to the pH of solution, by mixture separating and filtering, must precipitate and filtrate, wash and dry gained precipitation, gained filtrate adjusts pH to equal 7 with sulfuric acid, then adopts the method for distillation to obtain solid sulphuric acid potassium and distilled water;

C. gained to be deposited in nitrogen atmosphere and to heat 2 ~ 10 minutes under 300 ~ 500 DEG C of conditions maybe by the method process 5 ~ 30 minutes of precipitation discharge of plasma in low temperature, obtained Mn ₃o ₄/ graphene complex.

The present invention directly utilizes the divalent manganesetion of graphite oxide and the potassium permanganate generation having graphite to generate in graphite oxidation process as generation Mn ₃o ₄the presoma of/graphene complex, need not isolate graphite oxide and add manganese source in addition, simplifying technical process, reduce cost; Adopt KOH, as precipitation reagent, the sulfuric acid in original discard solution is transformed to byproduct K ₂sO ₄, isolated water can also recycle, and improves value-added content of product, reduce further cost; Whole process produces without any pollutant and discarded object, is beneficial to environmental protection, is applicable to large-scale production.Its specific area of the electrode prepared with the material that the present invention produces is 20 ~ 100m ²/ g, electrochemistry capacitance reaches 100 ~ 500F/g.

Accompanying drawing explanation

Fig. 1 is the process chart of the embodiment of the present invention.

Fig. 2 is the embodiment of the present invention 1 gained Mn ₃o ₄the XRD spectra of/graphene complex.

Fig. 3 is embodiment 1 gained Mn ₃o ₄the transmission electron microscope photo of/graphene complex.

Fig. 4 is embodiment 1 gained Mn ₃o ₄the cyclic voltammetry curve of/graphene complex.

Fig. 5 is embodiment 1 gained K ₂sO ₄pure K is analyzed with commercialization ₂sO ₄xRD spectra.

Embodiment

Embodiment 1:

Technological process is as shown in Figure 1:

A. being added to by 1.0g crystalline flake graphite and filling 23ml concentration is in the beaker of 98% concentrated sulfuric acid, stirs 2 hours, slowly in beaker, add 3.0g potassium permanganate under ice bath, continues to stir 2 hours under condition of ice bath; The beaker filling mixture is placed in 40 DEG C of water-baths 1 hour, more slowly adds 58ml distilled water wherein, after stirring, again bath temperature is risen to 98 DEG C, stir 1 hour; From water-bath, take out beaker, slowly add the warm water of 140ml 60 DEG C under stirring condition, stirring condition borehole cooling to 25 DEG C, in beaker, add the hydrogen peroxide that 5ml concentration is 30%, obtain after stirring containing graphite oxide, SO ₄ ^2-, K ⁺, Mn ²⁺and H ⁺graphite oxide mother liquor;

B. under the condition constantly stirring and blast air, the KOH solution dropwise adding 1M in graphite oxide mother liquor prepared by a step reaches 11 to the pH of solution, mixture centrifugation is filtered, gained precipitation is washed with distilled water to neutrality, drying 12 hours in 80 DEG C of baking ovens, is Mn through washing, dry precipitation ₃o ₄/ graphite oxide composite; Gained filtrate adjusts pH to equal 7 with sulfuric acid, then adopts the method for distillation to obtain solid sulphuric acid potassium and distilled water;

C. by gained Mn ₃o ₄/ graphite oxide composite in nitrogen atmosphere 500 DEG C heating 2 minutes, collect sample, obtain Mn ₃o ₄/ graphene complex.

Utilize nitrogen adsorption assay gained Mn ₃o ₄the specific area of/graphene complex: adsorption temp is liquid nitrogen temperature (77K), recording specific area is 44m ²/ g.

Utilize 2M (NH ₄) ₂sO ₄three-electrode system as electrolyte tests its electrochemistry ratio capacitance: nickel foam is cut into the circular electric pole piece that diameter is 15mm, weigh 120 DEG C of dryings after 12 hours.Get Mn ₃o ₄/ graphene complex 5.0mg, at 100 DEG C, vacuumize 10 hours, then adds the ethanolic solution of the polytetrafluoroethylene of 0.6% of 93.0 mg, then adds appropriate absolute ethyl alcohol, and ultrasonic disperse 5 minutes, obtains dispersion liquid.Then dispersion liquid is dried to half-dried in 80 DEG C of baking ovens, solid is placed on after stainless steel substrates is pressed into thin slice, the disk that diameter is about 10mm is cut into card punch, by this wafer presser in the middle of two foam nickel electrode sheets, nickel strap is inserted between sample disk and foam nickel electrode sheet, finally by obtained electrode at 100 DEG C dry 12 hours, deduct the quality of original two foam nickel electrode sheets and a nickel strap after weighing, calculate effective Mn ₃o ₄the quality of/graphene complex, by ready-made electrode slice at 2 M (NH ₄) ₂sO ₄soak in solution after 12 hours and measure its capacitive property, under charging and discharging currents 50mA/g, electrochemistry capacitance is 316F/g.

Gained Mn ₃o ₄the XRD spectra of/graphene complex as shown in Figure 2.

Gained Mn ₃o ₄the transmission electron microscope photo of/graphene complex as shown in Figure 3.

Gained Mn ₃o ₄the cyclic voltammetry curve people of/graphene complex as shown in Figure 4.

Gained K ₂sO ₄pure K is analyzed with commercialization ₂sO ₄xRD spectra as shown in Figure 5.

Embodiment 2:

Technological process is as shown in Figure 1:

A. being added to by 1.0g crystalline flake graphite and filling 16.3ml concentration is in the beaker of 98% concentrated sulfuric acid, stirs 5 hours, slowly in beaker, add 5.0g potassium permanganate under ice bath, continues to stir 5 hours under condition of ice bath; The beaker filling mixture is placed in 35 DEG C of water-baths 3 hours, more slowly adds 30ml distilled water wherein, after stirring, again bath temperature is risen to 98 DEG C, stir 2 hours; From water-bath, take out beaker, slowly add the warm water of 100ml 60 DEG C under stirring condition, stirring condition borehole cooling to 20 DEG C, in beaker, add the hydrogen peroxide that 1ml concentration is 30%, obtain after stirring containing graphite oxide, SO ₄ ^2-, K ⁺, Mn ²⁺and H ⁺graphite oxide mother liquor;

B. under the condition constantly stirring and blast air, the KOH solution dropwise adding 1M in graphite oxide mother liquor prepared by a step reaches 10 to the pH of solution, mixture centrifugation is filtered, gained precipitation is washed with distilled water to neutrality, drying 12 hours in 80 DEG C of baking ovens, is Mn through washing, dry precipitation ₃o ₄/ graphite oxide composite; Gained filtrate adjusts pH to equal 7 with sulfuric acid, then adopts the method for distillation to obtain solid sulphuric acid potassium and distilled water;

C. by gained Mn ₃o ₄/ graphite oxide composite in nitrogen atmosphere 300 DEG C heating 10 minutes, collect sample, obtain Mn ₃o ₄/ graphene complex.

Utilize nitrogen adsorption assay gained Mn ₃o ₄the specific area of/graphene complex, adsorption temp is liquid nitrogen temperature (77K), and recording specific area is 49m ²/ g.

The electrode utilizing method in the same manner as in Example 1 to prepare is in identical test system, and under charging and discharging currents 50mA/g, electrochemistry capacitance is 420 F/g.

Embodiment 3:

Technological process is as shown in Figure 1:

A. being added to by 1.0g crystalline flake graphite and filling 32.6ml concentration is in the beaker of 98% concentrated sulfuric acid, stirs 10 hours, slowly in beaker, add 8.0g potassium permanganate under ice bath, continues to stir 10 hours under condition of ice bath; The beaker filling mixture is placed in 50 DEG C of water-baths 6 hours, more slowly adds 100ml distilled water wherein, after stirring, again bath temperature is risen to 98 DEG C, stir 4 hours; From water-bath, take out beaker, slowly add the warm water of 200ml 60 DEG C under stirring condition, stirring condition borehole cooling to 30 DEG C, in beaker, add the hydrogen peroxide that 1ml concentration is 30%, obtain after stirring containing graphite oxide, SO ₄ ^2-, K ⁺, Mn ²⁺and H ⁺graphite oxide mother liquor;

B. under the condition constantly stirring and blast air, the KOH solution dropwise adding 1M in graphite oxide mother liquor prepared by a step reaches 13 to the pH of solution, mixture centrifugation is filtered, gained precipitation is washed with distilled water to neutrality, drying 12 hours in 80 DEG C of baking ovens, is Mn through washing, dry precipitation ₃o ₄/ graphite oxide composite; Gained filtrate adjusts pH to equal 7 with sulfuric acid, then adopts the method for distillation to obtain solid sulphuric acid potassium and distilled water;

C. by gained Mn ₃o ₄the method process of/graphite oxide composite use discharge of plasma in low temperature in nitrogen atmosphere 5 ~ 30 minutes, obtained Mn ₃o ₄/ graphene complex.

Utilize nitrogen adsorption assay gained Mn ₃o ₄the specific area of/graphene complex, adsorption temp is liquid nitrogen temperature (77K), and recording specific area is 55m ²/ g.

The electrode utilizing method in the same manner as in Example 1 to prepare is in identical test system, and under charging and discharging currents 50mA/g, electrochemistry capacitance is 280 F/g.

Claims (1)

1. a high specific capacitance Mn ₃o ₄the environment-friendly preparation method thereof of/graphene combination electrode material, is characterized in that carrying out as follows successively:

A. being added to by graphite and filling concentration is in the beaker of 98% concentrated sulfuric acid, stirs 2 ~ 10 hours, slowly in beaker, add potassium permanganate under ice bath, continues to stir 2 ~ 10 hours under condition of ice bath; The beaker filling mixture is placed in 35 ~ 50 DEG C of water-baths 1 ~ 6 hour, more slowly adds distilled water wherein, after stirring, again bath temperature is risen to 98 DEG C, stir 1 ~ 4 hour; From water-bath, take out beaker, slowly add the warm water of 60 ~ 80 DEG C under stirring condition, stirring condition borehole cooling to 20 ~ 30 DEG C, in beaker, add the hydrogen peroxide that concentration is 30%, after stirring, obtain graphite oxide mother liquor; The amount ratio of described reactant is graphite: the concentrated sulfuric acid: potassium permanganate: hydrogen peroxide: distilled water: warm water=1g:16.3 ~ 32.6ml:3 ~ 8g:1 ~ 5ml:30 ~ 100ml:100 ~ 200ml;

B., under the condition constantly stirring and blast air, in graphite oxide mother liquor prepared by a step, dropwise add KOH solution reach 10 ~ 13 to the pH of solution, by mixture separating and filtering, must precipitate and filtrate; Wash and dry gained precipitation, gained filtrate adjusts pH to equal 7 with sulfuric acid, then adopts the method for distillation to obtain solid sulphuric acid potassium and distilled water;

C. gained to be deposited in nitrogen atmosphere and to heat 2 ~ 10 minutes under 300 ~ 500 DEG C of conditions maybe by the method process 5 ~ 30 minutes of precipitation discharge of plasma in low temperature, obtained Mn ₃o ₄/ graphene complex.