CN101913556B - Preparation method of cobalt-silicon oxide/carbon nanocomposite - Google Patents
Preparation method of cobalt-silicon oxide/carbon nanocomposite Download PDFInfo
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Abstract
The invention discloses a preparation method of a cobalt-silicon oxide/carbon nanocomposite, belonging to the field of electrochemical techniques. The preparation method comprises the following steps of: mixing tetraethoxysilane, polyvinylpyrrolidone, a carbon source, a cobalt source and deionized water, and uniformly stirring to prepare a solution A; mixing sodium hydroxide, sodium borohydride and deionized water, and uniformly stirring to prepare a solution B; adding the solution B into the solution A, uniformly stirring, and then pouring the mixture into a water heating pot; placing the water heating pot in an oven to obtain a product, then washing the product with deionized water and absolute ethyl alcohol, filtering, and then placing the product in the oven for drying; and calcining the obtained powder to obtain the cobalt-silicon oxide/carbon nanocomposite. The method of the invention has the advantages of strong operability, good reproducibility and stable product quality. The cobalt-silicon oxide/carbon nanocomposite prepared by the method of the invention has high electric conductivity as well as high reversible capacity and favorable cycle performance when being applied in lithium ion batterys.
Description
Technical field
The invention belongs to technical field of electrochemistry, be specifically related to a kind of method for preparing cobalt-silica/carbon nano-composite material by hydro thermal method.
Technical background
Lithium ion battery is the highest a kind of portable chemical power supply of present specific energy.Current, the negative material that the commercial li-ion battery uses concentrates on material with carbon element, but carbon negative pole material exist specific capacity low, easily the shortcomings such as organic solvent embeds altogether occur, affected its application in high specific energy, high power type battery.Studies show that when the specific capacity of negative material can significantly improve total specific capacity of lithium ion battery during at 1000～1200mAh/g, so the research and development of Novel anode material get most of the attention.Silicon has caused more and more insiders' concern as the highest negative material of theoretical capacity in the various alloys of at present research, and lithium can obtain different products from pasc reaction, such as Li
12Si
7, Li
13Si
4, Li
7Si
3, Li
22Si
5Deng, Li
22Si
5Theory insertion amount reach 4200mAh/g, the termination current potential that lithium inserts silicon can be controlled at more than the 0.2V, can significantly improve capacity and the security performance (S.Bourderaus of battery, T.Brousse, D.M.Schleich.Amorphous silicon as a possible anode material for Li-ion batteries.Journal ofPower Sources, 1999,81 (81-82): 233～236).But, the Si sill is taking off, will experience serious volumetric expansion and contraction (volume change: 280%～300%) in the cyclic process of embedding lithium, cause destruction and the mechanical efflorescence of material structure, cause between electrode material and the separating of electrode material and collector, and then lose and electrically contact, cause capacity to be decayed rapidly.By alloying (G.X.Wang, L.Sun, D.H.Bradhust, et al..Nanocrystalline NiSi alloy as an anode material for lithium-ionbatteries.Journal of Alloys and Compounds, 2000,306:249～252) method can be improved cycle performance to a certain extent, but does not have to solve the problem of Si sill cyclical stability at all.Adopted afterwards nanometer oxide particle, because silica is in embedding lithium process first, form lithia, and the variation that lithia can slow down volume in the charge and discharge process as inert fraction, stability and cycle performance (J.Yang, the Y.Takeda of raising structure, N.Imanishi, et al..SiOx-based anodes forsecondary lithium batteries.Solid State Ionics, 2002,152-153:125-129).Yet easily reunite between the nano particle, the electricity of nano particle is reunited so that material loses nano-meter characteristic gradually in cyclic process, capacity attenuation is rapid, and silica irreversible capacity is larger first, so the nano silicon oxide negative material still has sizable distance from practical.Therefore the present invention is directed to the problems such as Si sill cyclical stability is poor, enclosed pasture efficient is low first, carrying out research extensively and profoundly aspect the design of material composition and the nano grain surface modification, design has also prepared Si base nano composite anode material: carbon coating cobalt-silica negative material, this material prepares by hydro thermal method, its Stability Analysis of Structures, even particle distribution, fail safe are good, specific capacity is high, and enclosed pasture efficient is high first, is a kind of rising lithium ion battery height ratio capacity negative material.And adopt cobalt-silica/carbon composite as lithium ion battery negative material, be assembled into lithium ion battery.
Summary of the invention
The object of the invention is to: provide the preparation method of a kind of cobalt-silica/carbon nano-composite material, for the production of cobalt-silica/carbon nano-composite material.
Purpose of the present invention realizes in the following manner:
The preparation method of a kind of cobalt-silica/carbon nano-composite material, the concrete preparation process of the method is as follows:
(1) obtain solution A: positive silicic acid vinegar ethyl ester, polyvinylpyrrolidone, carbon source, cobalt source and deionized water are mixed, stir, make solution A.Wherein, the volume ratio of positive silicic acid vinegar ethyl ester and deionized water is 1: 10-1: 30, and the mass ratio of polyvinylpyrrolidone and silicon dioxide is 2: 1-1: 3, the mol ratio of carbon source and silicon dioxide is 1: 1-10: 1, the mol ratio of cobalt source and silicon dioxide is 1: 2-1: 6.
Obtain solution B: NaOH, sodium borohydride and deionized water are mixed, stir, make solution B.Wherein, the mol ratio in NaOH and cobalt source is 2: 1-5: 1, the mol ratio in sodium borohydride and cobalt source is 2: 1-5: 1, the mass ratio of NaOH and deionized water is 1: 5-1: 80;
(2) solution B is joined solution A, continue to be stirred to evenly, pour in the hydro-thermal tank;
(3) the hydro-thermal tank is placed baking oven, 130-180 ℃ is incubated 5-48 hour;
(4) with step (3) products therefrom with deionized water and absolute ethanol washing, filtration after, place baking oven 80-120 ℃ oven dry;
(5) heat treatment: the powder of step (4) gained in inert atmosphere, under 400-1000 ℃ of temperature calcination 0.5-10 hour, is obtained cobalt-silica/carbon nano-composite material.
Carbon source in the described step (1) is sucrose, glucose, starch, epoxy resin or phenolic resins; Described cobalt source is cobalt nitrate, cobalt chloride, cobalt acetate or cobalt oxalate.
In the described step (2), solution B is poured in the solution A fast or with solution B with 15-60 drip/speed of min is added dropwise to solution A.When being poured into fast solution B in the solution A, react more violent, product crystal grain is less.Cobalt-the silica that is made by preparation method of the present invention/carbon nano-composite material, the particle diameter of its particle are tens to the hundreds of nanometer, can be used as the application of lithium ion battery negative material.
Cobalt-silica that the preparation method of described cobalt-silica/carbon nano-composite material makes/carbon nano-composite material, its particle diameter are 10～900nm.
The invention has the advantages that:
(1) the method makes the nano material after the finishing embed and deviate from the process at lithium, avoid the reunion between the nano particle, improved the cyclical stability of electrode material, improve the conductivity of material, and cobalt mix the first irreversible capacity that has reduced silica, improved the first enclosed pasture efficient of material.
(2) the method embeds and takes off in the embedding process at lithium ion, suppresses the volumetric expansion of silicon materials, makes lithium ion battery have high reversible capacity and good cycle performance.
(3) the inventive method is workable, favorable reproducibility, and products obtained therefrom steady quality.And the synthesis technique of material is simple, when being used for lithium ion battery negative material, specific capacity is higher, stable cycle performance.
Description of drawings
Fig. 1 is the cycle performance curve of the synthetic cobalt-silica of hydro thermal method of the present invention/carbon nano-composite material.
Embodiment
Embodiment 1
Positive silicic acid vinegar ethyl ester, 1.5g polyvinylpyrrolidone, 11.4g sucrose, 1.58gCoCl with 7.5ml
26H
2O and 100ml deionized water mix, stir, make solution A, 0.531g NaOH, 0.55g sodium borohydride and 20ml deionized water are mixed, stir, make solution B, the speed of solution B with 30/min is joined in the solution A, continue to stir, pour in the hydro-thermal tank, and place baking oven, 140 ℃ are incubated 24 hours, after products therefrom usefulness deionized water and absolute ethanol washing, the filtration, place 80 ℃ of oven dry of baking oven, the powder of gained in inert atmosphere, 500 ℃ of lower calcination 3 hours, finally obtain cobalt-silica/carbon nano-composite material.
The conductive agent acetylene black that synthetic material is added 15wt%, the binding agent PVDF of 15wt% makes slurry, evenly be applied on the Copper Foil, after the oven dry, block circular pole piece, form test cell with lithium metal, carry out the constant current charge-discharge experiment, charging and discharging currents is 100mA/g, and the charging/discharging voltage scope control is between 0.01-3.0V.The maximum reversible capacity of the cobalt-silica/carbon negative pole material of preparation is about 900mAh/g, and the specific capacity that circulates after 50 times is 775mAh/g, and capability retention is 81%.Be illustrated in figure 1 as the cycle performance curve of the synthetic cobalt-silica of hydro thermal method of the present invention/carbon nano-composite material.
Embodiment 2
Positive silicic acid vinegar ethyl ester with 7.5ml, 1.5g polyvinylpyrrolidone, 11.4g starch, 4.15g four hydration cobalt acetates and 100ml deionized water mix, stir, make solution A, with 1.33g NaOH, 1.26g sodium borohydride and 20ml deionized water mix, stir, make solution B, solution B is poured into solution A fast, continues to stir, pour in the hydro-thermal tank, and place baking oven, 160 ℃ are incubated 12 hours, products therefrom deionized water and absolute ethanol washing, after the filtration, place 100 ℃ of oven dry of baking oven, the powder of gained is in inert atmosphere, 600 ℃ of lower calcination 2 hours finally obtain cobalt-silica/carbon nano-composite material.
The conductive agent acetylene black that synthetic material is added 15wt%, the binding agent PVDF of 15wt% makes slurry, evenly be applied on the Copper Foil, after the oven dry, block circular pole piece, form test cell with lithium metal, carry out the constant current charge-discharge experiment, charging and discharging currents is 100mA/g, and the charging/discharging voltage scope control is between 0.01-3.0V.The maximum reversible capacity of the cobalt-silica/carbon negative pole material of preparation is about 484mAh/g, and the specific capacity that circulates after 50 times is 396mAh/g, and capability retention is 81.8%.
Embodiment 3
Positive silicic acid vinegar ethyl ester, 1.5g polyvinylpyrrolidone, 19.6g glucose, 1.93gCo (NO with 7.5ml
3)
26H
2O and 110ml deionized water mix, stir, make solution A, 0.531g NaOH, 0.55g sodium borohydride and 15ml deionized water are mixed, stir, make solution B, the speed of solution B with 45/min is joined in the solution A, continue to stir, pour in the hydro-thermal tank, and place baking oven, 180 ℃ are incubated 10 hours, after products therefrom usefulness deionized water and absolute ethanol washing, the filtration, place 120 ℃ of oven dry of baking oven, the powder of gained in inert atmosphere, 700 ℃ of lower calcination 1 hour, finally obtain cobalt-silica/carbon nano-composite material.
The conductive agent acetylene black that synthetic material is added 15wt%, the binding agent PVDF of 15wt% makes slurry, evenly be applied on the Copper Foil, after the oven dry, block circular pole piece, form test cell with lithium metal, carry out the constant current charge-discharge experiment, charging and discharging currents is 100mA/g, and the charging/discharging voltage scope control is between 0.01-3.0V.The maximum reversible capacity of the cobalt-silica/carbon negative pole material of preparation is about 480mAh/g, and the specific capacity that circulates after 50 times is 384mAh/g, and capability retention is 80%.
Claims (4)
1. the preparation method of cobalt-silica/carbon nano-composite material is characterized in that, concrete preparation process is as follows:
(1) obtain solution A: positive silicic acid vinegar ethyl ester, polyvinylpyrrolidone, carbon source, cobalt source and deionized water are mixed, stir, make solution A; Wherein, the volume ratio of described positive silicic acid vinegar ethyl ester and deionized water is 1: 10-1: 30, and the mass ratio of polyvinylpyrrolidone and silicon dioxide is 2: 1-1: 3, the mol ratio of carbon source and silicon dioxide is 1: 1-10: 1, the mol ratio of cobalt source and silicon dioxide is 1: 2-1: 6;
Obtain solution B: NaOH, sodium borohydride and deionized water are mixed, stir, make solution B; Wherein, the mol ratio in NaOH and cobalt source is 2: 1-5: 1, the mol ratio in sodium borohydride and cobalt source is 2: 1-5: 1, the mass ratio of NaOH and deionized water is 1: 5-1: 80;
(2) solution B is joined solution A, continue to be stirred to evenly, pour in the hydro-thermal tank;
(3) the hydro-thermal tank is placed baking oven, 130-180 ℃ is incubated 5-48 hour;
(4) with step (3) products therefrom with deionized water and absolute ethanol washing, filtration after, place baking oven 80-120 ℃ oven dry;
(5) heat treatment: the powder of step (4) gained in inert atmosphere, under 400-1000 ℃ of temperature calcination 0.5-10 hour, is obtained cobalt-silica/carbon nano-composite material.
2. the preparation method of cobalt-silica according to claim 1/carbon nano-composite material is characterized in that, the carbon source in the described step (1) is sucrose, glucose, starch, epoxy resin or phenolic resins; Described cobalt source is cobalt nitrate, cobalt chloride, cobalt acetate or cobalt oxalate.
3. the preparation method of cobalt-silica according to claim 1/carbon nano-composite material is characterized in that, in the described step (2), with solution B with 15-60 drip/speed of min is added dropwise to solution A.
4. the preparation method of cobalt-silica according to claim 1/carbon nano-composite material is characterized in that, cobalt-silica that the preparation method of described cobalt-silica/carbon nano-composite material makes/carbon nano-composite material, its particle diameter are 10-900nm.
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| CN103703592A (en) * | 2011-07-29 | 2014-04-02 | 住友电木株式会社 | Method for producing carbon material for lithium ion secondary batteries, carbon material for lithium ion secondary batteries, negative electrode active material for lithium ion secondary batteries, composition, carbon composite material for negative |
| CN102646820B (en) * | 2012-05-04 | 2014-05-07 | 南开大学 | Negative material for lithium ion secondary batteries and preparing method thereof |
| JP6156089B2 (en) * | 2012-12-10 | 2017-07-05 | 信越化学工業株式会社 | Silicon oxide and manufacturing method thereof, negative electrode, lithium ion secondary battery and electrochemical capacitor |
| CN105006575B (en) * | 2015-06-23 | 2019-06-04 | 西安博纳材料科技有限公司 | A kind of preparation method of metal oxide-carbon composite materials |
| CN104941584B (en) * | 2015-07-06 | 2017-08-25 | 河北工业大学 | Heavy metal ion SiO in a kind of adsorbed water body2/ C composite and its application |
| CN105742589B (en) * | 2016-02-29 | 2018-09-18 | 中国有色桂林矿产地质研究院有限公司 | A kind of negative electrode of lithium ion battery silicon-cobalt-carbon composite and preparation method thereof |
| CN108232144B (en) * | 2017-12-25 | 2020-09-25 | 北方奥钛纳米技术有限公司 | Modified silicon-carbon composite electrode material and preparation method thereof |
| CN110284146A (en) * | 2019-06-21 | 2019-09-27 | 青岛科技大学 | Load selenium in situ adulterates molybdenum disulfide/transition metal boride nano material preparation and application |
| CN110635129B (en) * | 2019-08-21 | 2022-08-09 | 合肥国轩高科动力能源有限公司 | Preparation method and application of silicon-based composite material |
| CN111029554A (en) * | 2019-12-25 | 2020-04-17 | 湖北万润新能源科技发展有限公司 | Preparation method and application of in-situ carbon-coated silicon dioxide-carbon composite material |
| CN111446440B (en) * | 2020-05-22 | 2022-07-05 | 扬州大学 | Nitrogen-doped carbon-coated hollow mesoporous silica/cobalt nano composite material and lithium ion battery cathode material thereof |
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