CN102336442B - K0.125MnO2 nanowire and preparation method thereof - Google Patents

Abstract

The invention relates to a K0.125MnO2 nanowire and a preparation method thereof. The length of the nanowire is in a range of 1 to 2 mu m, and the diameter of the nanowire is in a range of 10 to 30 nm. The MnO2 nanowire containing potassium prepared by the method has a one-dimensional structure and has a remarkable potential application prospect in the field of electrode materials of super capacitors and lithium ion batteries. The preparation method has the advantages of mild preparation conditions, good repeatability and a wide application prospect.

Description

K 0.125MnO 2Nano wire and preparation method thereof

Technical field

The present invention relates to a kind of wire K _0.125MnO ₂Nano material and preparation method thereof belongs to inorganic chemistry and field of material synthesis technology.

Background technology

Ultracapacitor is a kind of electrochemical capacitor that has near energy content of battery density, compare with traditional capacitor, it is fast that ultracapacitor discharges and recharges speed with it, environmental friendliness, and the cycle life of overlength, be expected to become novel green energy resource of 21 century, it is applied to every field, for example: communication terminal, notebook computer, electric automobile etc.At present, the electrode material of ultracapacitor mainly comprises three kinds: transition metal oxide, conducting polymer and material with carbon element.

Wherein, in various transition metal oxides, MnO ₂Because of have low cost, high capacitance is considered to have most the electrode material of application potential.Therefore, researchers synthesize the MnO with different-shape and structure by the whole bag of tricks ₂Synthetic MnO ₂Main method can be divided into electrochemical process and chemical method.Though the former have the time short, obtain the purer advantage of product but it at first will prepare a high and non-staining electrode basement of conduction, be suitable for the synthetic big compound of specific surface that has.And the latter can obtain the MnO of pattern variation (as particle, bar-shaped and wire etc.), short texture by means such as redox reaction, heat treatments ₂As the electrode material of ultracapacitor, MnO ₂Very high theoretical capacitance (can reach 1370 F/g) is arranged, but because of its poorly conductive (10 ^-5~ 10 ^-6S/cm), capacitive property depended on architectural characteristic, causes experimental result and theoretical numerical value to have bigger gap.On aspect the electrochemical process of electrode, MnO ₂Architectural characteristic and its electrochemical efficiency have close relationship: the MnO that has only one-dimentional structure (as nano wire, nanometer rods etc.) ₂More effective electronics transmission channels just can be provided, thereby reduce the decay of the capacitance of electrode.Yet present research is about the MnO of the especially nanometer wire of synthesizing one-dimensional structure ₂Rare report.

Summary of the invention

The object of the present invention is to provide a kind of K _0.125MnO ₂The preparation method of nano wire.

Do not achieve the above object, the present invention is with manganese acetate (Mn (CH ₃COO ₂) 4H ₂O) and potassium permanganate (KMnO ₄) be the manganese source, ethanol (C ₂H ₅OH) be solvent, under the synergy of mesoporous carbon, prepared the MnO that contains potassium by the method that chemical synthesis is combined with heat treatment phase ₂Nano wire.

The present invention adopts following technical scheme:

A kind of K _0.125MnO ₂Nano wire is characterized in that its length of described nano wire at 1～2 μ m, and diameter is at 10～30 nm.

A kind of above-mentioned K _0.125MnO ₂The preparation method of nano wire is characterized in that the concrete steps of this method are:

(1) with mesoporous carbon under the vacuum condition of-0.1～0.09 MPa, behind 80～85 ℃ of constant temperature 2～2.5 h, temperature is transferred to 55～60 ℃; (volume ratio of water and ethanol is 20:7～20:8), be stirred to solvent by evaporate to dryness, adds washed with de-ionized water, filters the back oven dry, obtains powder to add the mixed solvent that manganese acetate and deionized water and ethanol is mixed with; The mass ratio of described mesoporous carbon and manganese acetate is 0.3:0.24～0.3:0.25;

(2) with the powder of step (1) gained under the vacuum state of 0.06～0.07 MPa, behind 80～85 ℃ of constant temperature 2～2.5 h, temperature remained in 40 ~ 90 ℃ the scope, add liquor potassic permanganate (being made into liquor potassic permanganate with deionized water), behind reaction 2 ~ 18 h, filter, wash, obtain black powder after the oven dry, be K _0.125MnO ₂/ CMK-3 compound; The mass ratio of described potassium permanganate and described powder is 0.63:0.26～0.64:0.28; (controlling the addition of potassium permanganate with the funnel of controllable flow amount);

(3) with the K of step (2) gained _0.125MnO ₂/ CMK-3 compound obtains K at 550～600 ℃ of calcining 5～6 h _0.125MnO ₂Nano wire.

Preparing with reference to the method for existing bibliographical information of above-mentioned mesoporous carbon synthesized: be template with the mesoporous silicon oxide, after itself and sucrose, sulfuric acid being pressed the mass ratio mixing of 1:1.25:0.14～3:3.75:0.42, add solvent deionized water, after handling 6 h under 100 ℃, handled 6 hours at 160 ℃ again, then in inert atmosphere, 900 ℃ of roastings to carbonization; Remove silica template with the hydrofluoric acid solution of 5 wt% then, finally by filtering, wash, drying, get meso-porous carbon material.

The inventive method is at first with manganese acetate Mn (CH ₃COO) ₂, deionized water and ethanol mixes, and joins in the mesoporous carbon, makes the Mn in the solution ²⁺Ionic adsorption is on the meso-porous carbon material surface; Use KMnO again ₄Solution, by concentration, time and temperature controlling, with KMnO ₄With the Mn that is attached to the meso-porous carbon material surface ²⁺Ion generation redox reaction forms K _0.125MnO ₂/ CMK-3 composite material is got rid of meso-porous carbon material at last by heat treated mode, obtain product and be pure K _0.125MnO ₂Nano wire.

Compared with prior art, the present invention has following remarkable advantage: the present invention adopts simple chemical synthesis process, under the synergy of mesoporous carbon, has prepared length about 1 μ m, the K of diameter about 30 nm _0.125MnO ₂Nano wire.Preparation condition gentleness of the present invention, good reproducibility, the K for preparing _0.125MnO ₂Nano wire can be used for the electrode material of ultracapacitor, lithium ion battery.

Description of drawings

The K of Fig. 1 for making among the embodiment 1 among the present invention _0.125MnO ₂X-ray diffraction (XRD) spectrogram.

The K of Fig. 2 for making among the embodiment 1 among the present invention _0.125MnO ₂/ CMK-3 composite material (is schemed a) and pure K _0.125MnO ₂Scanning electron microscopy (SEM) photo of (figure b).

The K of Fig. 3 for making among the embodiment 1 among the present invention _0.125MnO ₂High resolution transmission electron microscopy (HRTEM) photo.

Embodiment

All embodiment are all undertaken by the operating procedure of technique scheme.

The preparation method of meso-porous carbon material CMK-3 sees also: Shinae Jun, Sang Hoon Joo, Ryong RyooMichal Kruk, Mietek Jaroniec, Zheng Liu, Tetsu Ohsuna, Osamu Terasaki. Synthesis of New, Nanoporous Carbon with Hexagonally Ordered Mesostructure. J. Am. Chem. Soc. 2000,122,10712-10713.

Embodiment 1:Preparation process and step in the present embodiment are as described below:

1. adopt electronic balance to take by weighing mesoporous carbon (CMK-3) material of 300 mg, be placed in the reaction vessel, the air in the container is extracted out again, make the container internal gas pressure keep-0.1 Mpa, temperature constant is at 80 ℃.Behind 2 h, temperature is adjusted to 60 ℃, with the Mn (CH of 20 mL, 0.05 mol/L ₃COO) ₂And 7 mL C ₂H ₅The mixed solution that OH prepares joins in the above-mentioned reaction vessel, magnetic agitation to solution by evaporate to dryness after, filter, washing, 80 ℃ obtain powder after the oven dry down;

2. the powder of gained is put into the another one reaction vessel, under the vacuum state of 0.06 MPa, fixed temperature is at 80 ℃.Behind 2 h, make its temperature remain on 60 ℃, with the KMnO of 200 mL, 0.02 mol/L ₄Solution joins in this container, react 18 h after, after filtration, washing, 80 ℃ down obtain black powder after the oven dry;

3. with black powder 600 ℃ of following roasting 6 h in Muffle furnace of gained, obtain pure K _0.125MnO ₂Nano wire.

The length of gained nano wire is 1～2 μ m, and diameter is 10～30 nm.

Embodiment 2:Implementation process except for the following differences, other are all identical with embodiment 1,

1. adopt electronic balance to take by weighing mesoporous carbon (CMK-3) material of 300 mg, be placed in the reaction vessel, the air in the container is extracted out again, make the container internal gas pressure keep-0.1 Mpa, temperature constant is at 80 ℃.Behind 2 h, temperature is adjusted to 60 ℃, with the Mn (CH of 20 mL, 0.10 mol/L ₃COO) ₂And 7 mL C ₂H ₅The mixed solution that OH prepares joins in the above-mentioned reaction vessel, magnetic agitation to solution by evaporate to dryness after, filter, washing, 80 ℃ obtain powder after the oven dry down;

The length of gained nano wire is 1～1.5 μ m, and diameter is 20～30 nm.

Embodiment 3:Implementation process except for the following differences, other are all identical with embodiment 1

2. the powder of gained is put into the another one reaction vessel, under the vacuum state of 0.06 MPa, fixed temperature is at 80 ℃.Behind 2 h, make its temperature remain on 70 ℃, with the KMnO of 200 mL, 0.02 mol/L ₄Solution joins in this container, react 16 h after, after filtration, washing, 80 ℃ down obtain black powder after the oven dry.The length of gained nano wire is 1～2 μ m, and diameter is 10～30 nm.

Embodiment 4:This implementation process except for the following differences, other are all identical with embodiment 1

2. the powder of gained is put into the another one reaction vessel, under the vacuum state of 0.06 MPa, fixed temperature is at 80 ℃.Behind 2 h, make its temperature remain on 60 ℃, with the KMnO of 200 mL, 0.02 mol/L ₄Solution joins in this container, react 12 h after, after filtration, washing, 80 ℃ down obtain black powder after the oven dry; The length of gained nano wire is 0.5～0.8 μ m, and diameter is 10～20 nm.

Products therefrom K among the above embodiment _0.125MnO ₂All have similar XRD spectra to embodiment 1, just the length of nano wire changes to some extent.Referring to accompanying drawing, Fig. 1 is products therefrom K in the embodiment of the invention 1 _0.125MnO ₂X-ray diffraction (XRD) spectrogram.XRD analysis: carry out CuK α diffraction at Japanese RigaKu D/max-2550 type X-ray diffractometer.As can be seen from Figure 2, the position of products therefrom diffraction maximum consistent with standard card (JCPDS Card No. 29-1020), and do not have other tangible stray crystals and occur mutually, prove by this method successfully to have prepared Cryptomelan-Q, the K of syn type _0.125MnO ₂Nano wire.

Referring to accompanying drawing, Fig. 2 is gained K in the embodiment of the invention 1 _0.125MnO ₂/ CMK-3 composite material (is schemed a) and pure K _0.125MnO ₂Scanning electron microscopy (SEM) photo of (figure b).Sem analysis: adopt the Japanese JEOL JSM-6700F of company type sem observation material pattern.By the contrast of front and back SEM photo, can see obviously that after the removal mesoporous carbon template, products therefrom has the nanostructure of one dimension wire, its length is about 1 μ m, and diameter is about 30 nm.

Referring to accompanying drawing, Fig. 3 is gained K in the embodiment of the invention 1 _0.125MnO ₂The high resolution transmission electron microscopy of nano wire (HRTEM) photo.HRTEM analyzes: adopt the Japanese JEOL JEM-2010F of company high resolution transmission electron microscopy to observe the material pattern.From the HRTEM photo, can more clearly observe, products therefrom has well-proportioned linear structure, and smooth surface, does not have other impurity and occurs, and this result is consistent with XRD, SEM.

Claims (1)

1. K _0.125MnO ₂The preparation method of nano wire, this nanowire length are 1～2 μ m, and diameter is characterized in that the concrete steps of this method are between 10～30 nm:

(1) with mesoporous carbon under the vacuum condition of-0.1～0.09 MPa, behind 80～85 ℃ of constant temperature 2～2.5 h, temperature is transferred to 55～60 ℃; Add the mixed solvent that manganese acetate and deionized water and ethanol are mixed with, wherein the volume ratio of water and ethanol is 20:7～20:8, is stirred to solvent by evaporate to dryness, adds washed with de-ionized water, filters the back oven dry, obtains powder; The mass ratio of described mesoporous carbon and manganese acetate is 0.3:0.24～0.3:0.25;

(2) with the powder of step (1) gained under the vacuum state of 0.06～0.07 MPa, behind 80～85 ℃ of constant temperature 2～2.5 h, temperature remained in 40 ~ 90 ℃ the scope, add liquor potassic permanganate, react after 2～18 hours, filter, wash, obtain black powder after the oven dry, be K _0.125MnO ₂/ CMK-3 compound; The mass ratio of described potassium permanganate and described powder is 0.63:0.26～0.64:0.28;

(3) with the K of step (2) gained _0.125MnO ₂/ CMK-3 compound obtains K at 550～600 ℃ of calcining 5～6 h _0.125MnO ₂Nano wire.

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