CN110697717B

CN110697717B - Sb/C battery cathode material with biological morph-genetic structure and preparation method thereof

Info

Publication number: CN110697717B
Application number: CN201910862744.7A
Authority: CN
Inventors: 王庆; 闫绳学; 周萌; 高成林; 罗绍华; 刘延国; 张亚辉; 王志远; 郝爱民
Original assignee: Northeastern University Qinhuangdao Branch
Current assignee: Northeastern University Qinhuangdao Branch
Priority date: 2019-09-12
Filing date: 2019-09-12
Publication date: 2021-09-21
Anticipated expiration: 2039-09-12
Also published as: CN110697717A

Abstract

The invention relates to a Sb/C battery cathode material with a biological morph-genetic structure and a preparation method thereof, which comprises the following steps of soaking diaphragma juglandis in acid liquor to obtain biological morph-genetic carbon with a retained raw material structure, and preparing an Sb/C composite material by a biological morph-genetic carbon composite method, wherein the Sb/C composite material has the following beneficial effects: 1. the electronic conductivity of Sb is improved by compounding with carbon; 2. the larger pore channels can provide a faster diffusion channel for the movement of K +, and the cellular thin-wall structure existing among different pore channels can shorten the transmission distance of K + in the Sb/C composite material, thereby improving the ionic conductivity of the Sb/C composite material; 3. the specific surface area of the material can be improved by a plurality of micro-porous channels, and the specific capacity of the battery can be increased along with the improvement of the specific surface area; 4. the pore structure in the biological morph-genetic carbon can be controllably adjusted through KOH activation, so that the relation between different structures and performances can be further researched.

Description

Sb/C battery cathode material with biological morph-genetic structure and preparation method thereof

Technical Field

The invention belongs to the field of energy materials, and particularly relates to a Sb/C battery cathode material with a biological morph-genetic structure and a preparation method thereof.

Background

At present, since researchers are still in the beginning stage of research on potassium ion batteries and mainly focus on the research on positive electrode materials, and the types of materials studied have many similar directions to Li + batteries, and the research on negative electrode materials of potassium ion batteries is also necessary, metal negative electrode materials are adopted herein: sb and a core wood (carbon source) are doped through hydrothermal treatment, so that the obtained composite carbon has high specific capacity of a metal material and stable cycle performance of a carbon-based negative electrode.

As described above, antimony is a K + battery alloy cathode with great potential, but with respect to the problems of low antimony ion and electronic conductivity, and easy occurrence of volume expansion, the existing research is actually to perform nanocrystallization treatment on Sb, for example, Sb is prepared into structures such as nanoscale rods and nanoscale tubes, so that the ion transmission path is shortened, the specific surface area of the material is increased, and the ion conductivity is further improved. Meanwhile, Sb and carbon are combined into a composite material, such as an Sb/C composite material and the like, so that the electronic conductivity and the electronic accommodation property of the active material are improved. However, there are many deficiencies in the research so far:

firstly, the nano Sb particles are easy to agglomerate, so that the problem of agglomeration is reduced by using a carbon-coated composite method; secondly, because the process for constructing the special structure is complex, great difficulty and uncertainty exist, and a simple method needs to be found for constructing the structure suitable for K + migration so as to realize controllable adjustment.

The biological morphgenetic material has a structure with multi-level distribution, the pore size distribution of the biological morphgenetic material is from nano-scale to micron-scale and is not the same, and the pore size of the biological morphgenetic material can be further increased by a KOH activation mode. The special hierarchical porous structure of the core-division wood is exactly in line with the ideal structure of the battery electrode material, and because the core-division wood has a plurality of pore passages with different sizes, different pore passages can provide different effects for the battery, electrolyte can be buffered in larger pores, the pore passages can also be used as the passages for the rapid transmission of ions, and a plurality of micro-pore passages can provide larger specific surface area for the carbon source.

If Sb and the biological morph-genetic carbon material with the hierarchical porous structure are compounded, Sb particles can uniformly enter a pore channel by firing through a tubular furnace, and the composite material constructed in the way has the following advantages: firstly, the electronic conductivity of Sb is improved by compounding with carbon; the larger pore channels can provide a faster diffusion channel for the movement of K +, and the cellular thin-wall structure existing among different pore channels can shorten the transmission distance of K + in the Sb/C composite material, thereby improving the ionic conductivity of the Sb/C composite material; the specific surface area of the material can be improved by the plurality of micro-pores, and the specific capacity of the battery can be increased along with the improvement of the specific surface area; the pore structure in the biological morph-genetic carbon can be controllably adjusted through KOH activation, so that the relation between different structures and performances can be further researched.

Disclosure of Invention

Aiming at the technical defects, the invention provides a Sb/C battery cathode material with a biological genetic structure and a preparation method thereof.

In order to achieve the purpose, the invention provides the following technical scheme:

a preparation method of a biological morph-genetic structure Sb/C battery negative electrode material comprises the following steps:

s1, selecting a core wood and mechanically stripping;

s2, cleaning the surface of the split core wood mechanically stripped in the step S1 with deionized water to remove impurities;

s3, putting the diaphragma juglandis processed in the step S2 into a drying oven for drying for 24 hours, and selecting a certain mass of dried diaphragma juglandis to be soaked in a hydrochloric acid solution with a certain concentration for 24 hours after drying;

s4, adding the diaphragma juglandis subjected to soaking in the step S3 and KOH into a cylindrical nickel boat according to a certain mass ratio, adding a proper amount of deionized water until the diaphragma juglandis completely soaked for 24 hours, covering with a preservative film and pricking;

s5, pouring out the KOH solution in the nickel boat, putting the nickel boat in a drying box at 60 ℃, and drying the air components for 48 hours;

s6, after being fully dried, the diaphragma juglandis is put into a nickel boat and put into a tube furnace, a certain temperature rise gradient is set, and the diaphragma juglandis is fired in argon atmosphere;

s7, after the firing is finished, naturally cooling the material to be below 80 ℃, closing the tube furnace and the argon bottle, cooling for 12 hours, and taking out the material;

s8, grinding the material cooled in the step S7 by using a mortar and enabling the material to pass through a 300-mesh sieve to obtain biological morph-genetic carbon;

s9, introducing 1g of sodium hypophosphite, 0.5g of biological morphgenetic carbon, 0.20g of sodium hydroxide and antimony trichloride into a reaction kettle and dissolving in ethanol;

s10, the reaction kettle cover is stirred for 2 hours by using a film. Then the reaction kettle is put into a large kettle and placed in a homogeneous reactor, the temperature is set to be 180 ℃, the rotating speed is 11, and the hydrothermal treatment is carried out for 12 hours;

s11, opening the reaction kettle after the reaction kettle is fully cooled, taking out the mixed liquid, and carrying out solid-liquid separation by using a high-speed centrifuge;

s12, taking out the solid, adding a large amount of deionized water, performing suction filtration by using a suction filtration instrument, and washing off NaCl in the solid phase;

s13, taking out the cleaned solid phase, putting the solid phase into a glass culture dish, and putting the glass culture dish into a drying oven to dry for 12 hours at the temperature of 60 ℃;

s14, placing the solid phase dried in the step S13, citric acid and deionized water in a glass cup, placing the glass cup on a magnetic stirrer, stirring for 30min, and then placing the glass cup in a drying oven for drying for 48 h;

and S15, placing the dried solid mixture in a nickel boat and placing the nickel boat in a tube furnace, setting a certain temperature rise gradient, and firing the mixture in an argon atmosphere to obtain the Sb/C battery cathode material with the biological morph-genetic structure.

Preferably, the mass of the split core wood after the completion of the drying in the step S3 is 25 g.

Preferably, the concentration of hydrochloric acid in the step S3 is 1 mol/L.

Preferably, in step S4, the mass ratio of cedar to KOH is 1: 1.

preferably, the temperature rise gradient in the step S6 is 60min for 20-200 ℃, the temperature rise is slowly carried out at 200-400 ℃ 20 according to 2 ℃/min, 200min for 400-800 ℃, and the temperature is preserved for 120min at 800 ℃.

Preferably, the temperature rise gradient in the step S15 is 60min at 20-200 ℃, 90min at 200-650 ℃, and then the temperature is kept at 650 ℃ for 4 h.

Compared with the prior art, the invention has the following beneficial effects:

1. the electronic conductivity of Sb is improved by compounding with carbon;

2. the larger pore channels can provide a faster diffusion channel for the movement of K +, and the cellular thin-wall structure existing among different pore channels can shorten the transmission distance of K + in the Sb/C composite material, thereby improving the ionic conductivity of the Sb/C composite material;

3. the specific surface area of the material can be improved by the plurality of micro-pores, and the specific capacity of the battery can be increased along with the improvement of the specific surface area;

4. the pore structure in the biological morph-genetic carbon can be controllably adjusted through KOH activation, so that the relation between different structures and performances can be further researched.

Drawings

FIGS. 1-4 are SEM, XRD, rate performance curves and impedance performance curves of electrode materials prepared by the direct compounding method.

FIGS. 5-8 are SEM, XRD, rate performance curves and impedance performance curves of electrode materials prepared by KOH activation recombination.

Fig. 9-12 are SEM, XRD, rate performance curves, and impedance performance curves of electrode materials prepared by the carbon coating method.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

s1, selecting a core wood and mechanically stripping;

s3, placing 25g of diaphragma juglandis processed in the step S2 into a drying oven for drying for 24 hours, and selecting a certain mass of dried diaphragma juglandis to be soaked in a hydrochloric acid solution with the concentration of 1mol/L for 24 hours after drying;

s4, mixing the diaphragma juglandis after the soaking in the step S3 with KOH according to the mass ratio of 1: 1, adding the mixture into a cylindrical nickel boat, adding a proper amount of deionized water until the mixture is completely soaked for 24 hours, covering a preservative film on the cylindrical nickel boat, and pricking holes;

s6, after fully drying, putting the core wood in a nickel boat, putting the core wood in a tube furnace, and keeping the core wood in an argon atmosphere

Baking, setting a heating gradient, namely heating at 20-200 ℃ for 60min, slowly heating at 200-400 ℃ according to 2 ℃/min, heating at 400-800 ℃ for 200min, and keeping the temperature at 800 ℃ for 120 min;

s15, placing the dried solid mixture in a nickel boat and placing the nickel boat in a tube furnace, setting a certain temperature rise gradient, namely, 60min is needed at the temperature of 20-200 ℃, 90min is needed at the temperature of 200-650 ℃, then, preserving heat for 4h at the temperature of 650 ℃, and performing protection firing in argon atmosphere to obtain the Sb/C battery cathode material with the biological morphotropic structure;

this compounding method is the KOH activated compounding method (diaphragma + KOH + SbCl 3).

Example 2

s1, selecting a core wood and mechanically stripping;

s3, diluting the diaphragma juglandis with deionized water until the PH value reaches 7;

s4, putting the diaphragma juglandis into the drying oven again, and drying for 48h at the temperature of 60 ℃. Fully drying the mixture;

s5, after being fully dried, the diaphragma juglandis is put in a nickel boat and put in a tube furnace, protected firing is carried out under argon atmosphere, and a temperature rise gradient is set, namely 60min is needed at 20-200 ℃, the temperature is slowly raised at 200-400 ℃ according to 2 ℃/min, 200min is needed at 400-800 ℃, and the temperature is preserved for 120min at 800 ℃;

s6, after the firing is finished, naturally cooling the material to be below 80 ℃, closing the tube furnace and the argon bottle, cooling for 12 hours, and taking out the material;

s7, grinding the material cooled in the step S7 by using a mortar and enabling the material to pass through a 300-mesh sieve to obtain biological morph-genetic carbon;

s8, introducing 1g of sodium hypophosphite, 0.5g of biological morphgenetic carbon, 0.20g of sodium hydroxide and antimony trichloride into a reaction kettle and dissolving in ethanol;

s9, the reaction kettle cover is stirred for 2 hours by using a film. Then the reaction kettle is put into a large kettle and placed in a homogeneous reactor, the temperature is set to be 180 ℃, the rotating speed is 11, and the hydrothermal treatment is carried out for 12 hours;

s10, opening the reaction kettle after the reaction kettle is fully cooled, taking out the mixed liquid, and carrying out solid-liquid separation by using a high-speed centrifuge;

s11, taking out the solid, adding a large amount of deionized water, performing suction filtration by using a suction filtration instrument, and washing off NaCl in the solid phase;

s12, taking out the cleaned solid phase, putting the solid phase into a glass culture dish, and putting the glass culture dish into a drying oven to dry for 12 hours at the temperature of 60 ℃;

s13, placing the pure Sb, the citric acid and the deionized water dried in the step S13 in a glass cup, placing the glass cup on a magnetic stirrer, stirring the glass cup for 30min, and then placing the glass cup in a drying oven to dry the glass cup for 48 h;

s14, placing the dried solid mixture in a nickel boat and placing the nickel boat in a tube furnace, setting a certain temperature rise gradient, namely, 60min is needed at the temperature of 20-200 ℃, 90min is needed at the temperature of 200-650 ℃, then, preserving heat for 4h at the temperature of 650 ℃, and performing protection firing in argon atmosphere to obtain the Sb/C battery cathode material with the biological morphotropic structure;

firstly, 10ml of ethanol is taken out by a 20ml measuring cylinder and placed in 4 glasses with the volume of 50ml and the glasses are marked as No. 1, No. 2, No. 3 and No. 4 respectively, and then 0.30g, 0.50g and 1g of SbCl3 are respectively weighed and added into the glasses with the volume of 2, No. 3 and No. 4, and the 4 glasses are marked as A group. Then, 4 parts of 15ml ethanol are respectively weighed by a 20ml measuring cylinder into 4 reaction kettles (which are marked as 1, 2, 3 and 4 and correspond to glass cups in the same way), 4 parts of 1g sodium hypophosphite (NaH 2PO 2. H2O) and 0.2g sodium hydroxide (NaOH) are respectively weighed by a medicine spoon and are respectively added into 4 reaction kettles, and the 4 reaction kettles are marked as group B. And placing A, B groups of beakers and reaction kettles into an ultrasonic cleaning instrument for ultrasonic treatment for 15 min. And after ultrasonic treatment, placing the B group of reaction kettles on a magnetic stirrer, adding a rotor for stirring, and slowly dropwise adding the solution in the A group into the reaction kettle corresponding to the B group by using a disposable rubber-head dropper. The reaction vessel was then stirred on the lid with a film for 2 h. Then the reaction kettle is put into a large kettle and placed in a homogeneous reactor (180 ℃, the rotating speed is about 11) for hydrothermal treatment for 8 hours.

This preparation is a direct compounding process (diaphragma + SbCl 3).

Example 3

s1, selecting a core wood and mechanically stripping;

s6, after being fully dried, the diaphragma juglandis is put in a nickel boat and put in a tube furnace, protected firing is carried out under argon atmosphere, and a temperature rise gradient is set, namely 60min is needed at 20-200 ℃, the temperature is slowly raised at 200-400 ℃ according to 2 ℃/min, 200min is needed at 400-800 ℃, and the temperature is preserved for 120min at 800 ℃;

s9, obtaining the nano-grade pure antimony, which comprises the following steps:

a: weighing 10ml of ethanol in a 20ml volumetric flask, putting the ethanol in a 50ml glass cup, and weighing 4.56g of SbCl3 in a spoon;

b: 15ml of ethanol is weighed in a 20ml volumetric flask and placed in a reaction kettle, then 2.44g of sodium hypophosphite and 0.30g of sodium hydroxide are weighed in a medicine spoon, and a beaker and the reaction kettle are placed in an ultrasonic cleaning instrument and are subjected to ultrasonic treatment for 15 min. And after ultrasonic treatment, placing the B group of reaction kettles on a magnetic stirrer, adding a rotor for stirring, and slowly dropwise adding the solution in the A group into the reaction kettle corresponding to the B group by using a disposable rubber-head dropper. The reaction vessel was then stirred on the lid with a film for 2 h. Then the reaction kettle is put into a large kettle and placed in a homogeneous reactor (180 ℃, the rotating speed is about 11) for hydrothermal treatment for 12 hours.

C: and opening the reaction kettle after the reaction kettle is fully cooled, taking out the mixed liquid, performing solid-liquid separation by using a high-speed centrifuge, centrifuging the mixed liquid for about 5 times in three pipes by taking absolute ethyl alcohol as a solvent until the pH value is neutral (to prevent residual Sb3+ from reacting with water to generate Sb2O 3), taking out the solid, adding a large amount of deionized water, and performing suction filtration by using a suction filtration instrument to wash off NaCl in the solid phase. Then, the washed solid phase was taken out and placed in a glass petri dish, and the dish was dried in a drying oven at 60 ℃ for 12 hours to obtain dry Sb.

This preparation is a carbon coating process (citric acid + SbCl 3).

Further, XRD test is carried out on the dried pure Sb to observe whether impurities are contained or not, and if the impurities are not contained, the molar mass ratio of the citric acid to the pure Sb is respectively 0: 1. 1: 2. 1: 1. 2: 1, (namely 0g, 0.96g, 1.92g and 3.84g of citric acid respectively) citric acid + deionized water + pure antimony, placing the mixture in a glass cup, placing the glass cup on a magnetic stirrer, stirring the mixture for 30min, and then placing the glass cup in a drying oven to dry the glass cup for 48 h. And placing the dried solid mixture in a nickel boat, placing the nickel boat in a tubular furnace, calcining the solid mixture at 650 ℃ under the protection of argon atmosphere, wherein 60min is needed when the temperature is increased from room temperature to 200 ℃, 90min is needed when the temperature is increased from 200 ℃ to 650 ℃, and then preserving the heat for 4h at 650 ℃, thereby obtaining the Sb/C material prepared by the carbon coating method.

The invention has the following beneficial effects:

1. the electronic conductivity of Sb is improved by compounding with carbon;

Claims

1. A preparation method of a biological morph-genetic structure Sb/C battery negative electrode material is characterized by comprising the following steps:

s1, selecting a core wood and mechanically stripping;

s10, stirring the reaction kettle cover by using a film for 2 hours, then filling the reaction kettle into a large kettle, placing the large kettle in a homogeneous reactor, setting the temperature at 180 ℃, the rotating speed at 11, and carrying out hydrothermal treatment for 12 hours;

and S15, placing the dried solid mixture in a nickel boat and placing the nickel boat in a tube furnace, setting a certain temperature gradient, and firing under an argon atmosphere to obtain the Sb/C battery cathode material with the biological morph-genetic structure.

2. The preparation method of the biological morph-genetic structure Sb/C battery negative electrode material according to claim 1, characterized in that: the mass of the diaphragma juglandis is 25g after the drying in the step S3 is finished.

3. The preparation method of the biological morph-genetic structure Sb/C battery negative electrode material according to claim 1, characterized in that: the concentration of the hydrochloric acid in the step S3 is 1 mol/L.

4. The preparation method of the biological morph-genetic structure Sb/C battery negative electrode material according to claim 1, characterized in that: in the step S4, the mass ratio of the central wood to the KOH is 1: 1.

5. the preparation method of the biological morph-genetic structure Sb/C battery negative electrode material according to claim 1, characterized in that: the temperature rise gradient in the step S6 is 60min for 20-200 ℃, the temperature is slowly raised at 200-400 ℃ according to 2 ℃/min, 200min for 400-800 ℃, and the temperature is preserved for 120min at 800 ℃.

6. The preparation method of the biological morph-genetic structure Sb/C battery negative electrode material according to claim 1, characterized in that: the temperature rise gradient in the step S15 is 60min at 20-200 ℃, 90min at 200-650 ℃, and then the temperature is kept for 4h at 650 ℃.

7. A biological morph-genetic structure Sb/C battery cathode material is characterized in that: the preparation method of the biological morph-genetic structure Sb/C battery negative electrode material is characterized by comprising the step of preparing the biological morph-genetic structure Sb/C battery negative electrode material according to any one of claims 1-6.