CN109638238B - Preparation method of electrode negative electrode material containing graphene - Google Patents
Preparation method of electrode negative electrode material containing graphene Download PDFInfo
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Abstract
A preparation method of an electrode negative electrode material containing graphene comprises the following steps: the preparation method comprises the steps of graphene microchip preparation, graphene microchip reduction and graphene/iron oxide electrode material preparation. The negative electrode material contains graphene nanoplatelets and Fe2O3The weight ratio of the particles is between 1:0.174 and 1:0.261, more than 85% Fe2O3The particles exist by covering the surfaces of the graphene micro-sheets with large radial dimension, and the graphene micro-sheets with large radial dimension are mutually adjacent in pairs and can not expose Fe2O3The surface to which the particles are attached is below 80%.
Description
Technical Field
The invention relates to the technical field of negative electrode materials containing graphene, in particular to a negative electrode material containing graphene and a preparation method thereof.
Background
Graphene is a two-dimensional material consisting of carbon atoms and having a thickness of only one atom, has very excellent physicochemical properties, such as excellent mechanical properties, high electrical conductivity, good thermal conductivity and the like, and is considered to be one of the most potential nano materials at present. As a one-dimensional carbon nano material, the carbon nano fiber has the advantages of good mechanical property, larger specific surface area, good chemical stability and the like, and the special properties enable the carbon nano fiber to be widely applied to the fields of catalyst carriers, polymer nano composite materials, flexible substrate materials of energy conversion and storage devices and the like. Taking the graphene microchip as an example, the graphene microchip not only has better physical properties and electrical properties, but also can be compounded with other materials to further improve the properties of other materials.
Graphene exists as an electrode material for preparing a negative electrode in the prior art, but has a large distance from the targets of stable structure, uniform dispersion and average electrical properties, and the article "Fe2O3The preparation of the cathode material of a lithium ion battery and the research of the electrochemical performance thereof provide Fe2O3The composite electrode material of particles and graphene oxide has poor properties and very uneven dispersion of the obtained product, and the graphene lamination phenomenon is very much, Fe2O3The particles are more and non-uniform in agglomeration and are dispersed on each surface position of graphene, and generally, the electrode material is only experimental in nature, and the charge and discharge performance and stability cannot be guaranteed when the material with the poor structure is applied in practical application.
Disclosure of Invention
The invention aims to provide an improved preparation method to solve the problems of uneven structure, insufficient performance and difficulty in practicability of an electrode material of a negative electrode containing graphene in the prior art.
In order to achieve the purpose, the invention provides the following technical scheme: a preparation method of an electrode negative electrode material containing graphene is characterized by comprising the following steps.
1) Preparing graphene nanoplatelets: taking a large number of prefabricated expanded graphite sheets as raw materials, and ultrasonically stripping the raw materials in absolute ethyl alcohol for more than 1-2h to generate graphene microchip dispersion liquid; taking out the upper-layer dispersion liquid through low-frequency ultrasound, and leaving the graphite which is not stripped in the container; supplementing the solvent absolute ethyl alcohol of the upper-layer dispersion liquid to more than 200-300ml, carrying out high-intensity ultrasonic oscillation for 3-5min, standing for 5-10s, immediately discarding half of the upper-layer dispersion liquid, supplementing the absolute ethyl alcohol to the volume of more than 200-300ml, and repeating the above processes for at least 10-20 times until the average radial size of the graphene nanoplatelets is confirmed to be more than 5-10um by AFM or SEM; and (4) evaporating all solvents in a rotary manner, and drying at normal temperature to obtain the graphene oxide micro-sheets with large radial sizes.
2) And (3) graphene nanoplatelets reduction: taking a four-mouth bottle with the volume of more than 2L, adding 180 parts by weight of double distilled water, inserting a stirring rod from the first mouth of the four-mouth bottle, stirring at 3-10 r/s, and keeping the temperature to be 35-45 ℃ for continuous stirring; slowly adding 0.2-0.4 weight part of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder grinding until the average particle size is below 60um from the second opening of the four-opening bottle; slowly adding 20 parts by weight of graphene oxide micro-sheets with large radial dimension from the second port of the four-port bottle, after all the graphene oxide micro-sheets are added, dissolving 5-10 parts by weight of ascorbic acid with double-distilled water at 35-45 ℃, keeping the solution of ascorbic acid under magnetic stirring at 35-45 ℃, and adding the ascorbic acid solution from the third port of the four-port bottle by using a dropper at the speed of 20-30 drops/min until the addition is finished; stirring for 10-15min, adding dropwise ammonia water from the third port, measuring pH value, and stopping adding ammonia water when pH value is stably higher than 7 and is kept for more than 5 min; and stirring for 10-15min, pouring out the mixture in the four-mouth bottle, removing supernatant, and continuously washing for 6 times by using excess absolute ethyl alcohol, double distilled water, absolute ethyl alcohol and double distilled water at about 40 ℃ to obtain the completely reduced graphene oxide micro-tablets with large radial sizes.
3) Preparation of graphene/Fe 2O3 electrode material
Taking a four-mouth bottle with the volume of more than 2L, putting 100-120ml double distilled water, inserting a stirring rod from the first mouth of the four-mouth bottle, stirring at 3-10 r/s, and keeping the temperature to be 35-45 ℃ for continuous stirring;
slowly adding 0.5-1g of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder crushing until the average particle size is below 60um from the second opening of the four-opening bottle, and then dripping 3-5ml of super-grade pure isopropanol at an extremely slow speed;
respectively taking 4-5g of FeCl2·4H2O and 3-4g of K2SO4Respectively grinding for more than 2h by using a mortar to ensure that the particle diameters of all particles are less than 300nm to obtain 4-5g of FeCl2·4H2Fine O powder and 3-4g of K2SO4Fine powder, respectively adding FeCl2·4H2O sieve barrel and K2SO4The lower surface of the sieve barrel is coated with microporous resin film with the aperture of 500-800 nm;
slowly adding 10-12g of graphene oxide micro-tablets with large radial dimension from the second opening of a four-opening bottle, continuously stirring for 15-20min after all the graphene oxide micro-tablets are added, and respectively using FeCl from the third opening and the fourth opening of the four-opening bottle2·4H2O sieve barrel and K2SO4The sieve barrel is used for mixing the 4-5g of FeCl2·4H2Fine O powder and 3-4g of K2SO4Sieving the fine powder at a very slow speed, wherein the adding process is not less than 15min, continuously stirring for 15-20min, and pouring the whole mixture into a hydrothermal reaction kettle;
hydrothermal circulation reaction: placing the hydrothermal reaction kettle into a thermostat at 90 ℃ for 3h, taking out, placing on a spin coater base, rotating at the speed of 2-5 r/s for 25-35min, placing back into the thermostat at 90 ℃, and repeating the hydrothermal-rotating steps for at least 3 times;
and pouring out the mixture in the hydrothermal reaction kettle, removing supernatant, continuously washing for 6 times by using excessive absolute ethyl alcohol, double distilled water, absolute ethyl alcohol and double distilled water at the temperature of about 40 ℃ to obtain a filter cake, spreading the filter cake in a container under the flowing nitrogen environment at the temperature of 30-40 ℃, and drying overnight to obtain the composite cathode material.
The graphene-containing electrode negative electrode material is prepared by the preparation method of the graphene-containing electrode negative electrode material, and is characterized in that: the negative electrode material contains graphene micro-sheets with large radial sizes and Fe2O3 particles, the weight ratio of the graphene micro-sheets with large radial sizes to the Fe2O3 particles is about 1: 0.174-1: 0.261, more than 85% of Fe2O3 particles are covered on the surfaces of the graphene micro-sheets with large radial sizes to exist, and the surfaces, on which the Fe2O3 particles are attached, of the graphene micro-sheets with large radial sizes are adjacent to each other in pairs and cannot be exposed are below 80%.
Compared with the prior art, the invention has at least the following beneficial effects: 1) select the graphite alkene microchip of big radial dimension, reduced the complex degree that the system mixes, mainly be like this at graphite alkene surface adhesion Fe2O 3's granule or aggregate, and use the graphite alkene of not selecting, because the size of own is not of uniform size, directly strengthened the system complex degree, also make the position and the effect that Fe2O3 adheres to hardly predict. 2) The property of the negative electrode material is guaranteed to be good, the performance of graphene oxide is not enough, the graphene is required to be changed into a reduction state, the conductivity of the reduction state graphene can meet the requirement of the negative electrode material, the attachment of Fe2O3 is easy to realize, how to guarantee the sufficient reduction of graphene nanoplatelets is achieved, a lot of adhesion and lamination are avoided, a small amount of PVA (polyvinyl alcohol) ultrafine powder is used, and due to the fact that the PVA ultrafine powder is an insulator, the excellent effect of promoting the dispersion of the graphene is achieved, and the process of reducing the graphene is sufficient and comprehensive. 3) The addition of the PVA micropowder in a trace amount also creates conditions for the uniform dispersion of Fe2O3, and due to the insulating property of the PVA micropowder, the material cannot easily agglomerate during adsorption and adhesion, and the insulating particles are similar to islands, thereby creating conditions for the low-agglomeration condition. 4) When Fe2O3 is attached to graphene, PVA ultrafine powder is continuously used, and island is formed relatively in the solution, so that the Fe2O3 is indirectly high in dispersion degree, and the method has a good technical effect on full dispersion and attachment/recombination of Fe2O 3.
Compared with the prior art, the scheme of the application has more directivity, obtains better technical effect and does not suggest.
Drawings
FIG. 1 is a schematic flow chart of the preparation method of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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
A preparation method of an electrode negative electrode material containing graphene is characterized by comprising the following steps.
1) Preparing graphene nanoplatelets: taking a large number of prefabricated expanded graphite sheets as raw materials, and ultrasonically stripping the raw materials in absolute ethyl alcohol for more than 1-2h to generate graphene microchip dispersion liquid; taking out the upper-layer dispersion liquid through low-frequency ultrasound, and leaving the graphite which is not stripped in the container; supplementing the solvent absolute ethyl alcohol of the upper-layer dispersion liquid to more than 200-300ml, carrying out high-intensity ultrasonic oscillation for 3-5min, standing for 5-10s, immediately discarding half of the upper-layer dispersion liquid, supplementing the absolute ethyl alcohol to the volume of more than 200-300ml, and repeating the above processes for at least 10-20 times until the average radial size of the graphene nanoplatelets is confirmed to be more than 5-10um by AFM or SEM; and (4) evaporating all solvents in a rotary manner, and drying at normal temperature to obtain the graphene oxide micro-sheets with large radial sizes.
2) And (3) graphene nanoplatelets reduction: taking a four-mouth bottle with the volume of more than 2L, adding 180 parts by weight of double distilled water, inserting a stirring rod from the first mouth of the four-mouth bottle, stirring at 3-10 r/s, and keeping the temperature to be 35-45 ℃ for continuous stirring; slowly adding 0.2-0.4 weight part of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder grinding until the average particle size is below 60um from the second opening of the four-opening bottle; slowly adding 20 parts by weight of graphene oxide micro-sheets with large radial dimension from the second port of the four-port bottle, after all the graphene oxide micro-sheets are added, dissolving 5-10 parts by weight of ascorbic acid with double-distilled water at 35-45 ℃, keeping the solution of ascorbic acid under magnetic stirring at 35-45 ℃, and adding the ascorbic acid solution from the third port of the four-port bottle by using a dropper at the speed of 20-30 drops/min until the addition is finished; stirring for 10-15min, adding dropwise ammonia water from the third port, measuring pH value, and stopping adding ammonia water when pH value is stably higher than 7 and is kept for more than 5 min; and stirring for 10-15min, pouring out the mixture in the four-mouth bottle, removing supernatant, and continuously washing for 6 times by using excess absolute ethyl alcohol, double distilled water, absolute ethyl alcohol and double distilled water at about 40 ℃ to obtain the completely reduced graphene oxide micro-tablets with large radial sizes.
3) graphene/Fe2O3Preparing an electrode material: taking a four-mouth bottle with a volume of more than 2L, putting 100-120ml double distilled water, inserting a stirring rod from the first mouth of the four-mouth bottle, stirring at 3-10 r/s, and keepingContinuously stirring at 35-45 deg.C; slowly adding 0.5-1g of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder crushing until the average particle size is below 60um from the second opening of the four-opening bottle, and then dripping 3-5ml of super-grade pure isopropanol at an extremely slow speed; respectively taking 4-5g of FeCl2·4H2O and 3-4g of K2SO4Respectively grinding for more than 2h by using a mortar to ensure that the particle diameters of all particles are less than 300nm to obtain 4-5g of FeCl2·4H2Fine O powder and 3-4g of K2SO4Fine powder, respectively adding FeCl2·4H2O sieve barrel and K2SO4The lower surface of the sieve barrel is coated with microporous resin film with the aperture of 500-800 nm; slowly adding 10-12g of graphene oxide micro-tablets with large radial dimension from the second opening of a four-opening bottle, continuously stirring for 15-20min after all the graphene oxide micro-tablets are added, and respectively using FeCl from the third opening and the fourth opening of the four-opening bottle2·4H2O sieve barrel and K2SO4The sieve barrel is used for mixing the 4-5g of FeCl2·4H2Fine O powder and 3-4g of K2SO4Sieving the fine powder at a very slow speed, wherein the adding process is not less than 15min, continuously stirring for 15-20min, and pouring the whole mixture into a hydrothermal reaction kettle; hydrothermal circulation reaction: placing the hydrothermal reaction kettle into a thermostat at 90 ℃ for 3h, taking out, placing on a spin coater base, rotating at the speed of 2-5 r/s for 25-35min, placing back into the thermostat at 90 ℃, and repeating the hydrothermal-rotating steps for at least 3 times; and pouring out the mixture in the hydrothermal reaction kettle, removing supernatant, continuously washing for 6 times by using excessive absolute ethyl alcohol, double distilled water, absolute ethyl alcohol and double distilled water at the temperature of about 40 ℃ to obtain a filter cake, spreading the filter cake in a container under the flowing nitrogen environment at the temperature of 30-40 ℃, and drying overnight to obtain the composite cathode material.
Example 2
The preparation method of the electrode negative electrode material containing graphene as in embodiment 1 is characterized in that: in the step (1), the graphene microchip dispersion liquid is generated through ultrasonic stripping for more than 1.5h in absolute ethyl alcohol; supplementing absolute ethanol to the upper layer dispersion liquid to above 220ml, high intensity ultrasonic oscillating for 4min, standing for 8s, supplementing absolute ethanol to above 220ml volume, and repeating above stepsThe process is carried out at least 15 times until the average radial dimension of the graphene nanoplatelets is confirmed to be higher than 5um by AFM or SEM; in the step (2), a stirring rod is inserted from the first port of the four-port bottle to stir at 4 revolutions per second, and the stirring is continuously carried out at the temperature of 35-40 ℃; slowly adding 0.2-0.3 weight part of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder grinding until the average particle size is below 60um from the second opening of the four-opening bottle; dissolving 5-7 weight parts of ascorbic acid in double distilled water at 35-40 deg.C, magnetically stirring at 35-40 deg.C, and adding via dropper at 24 drops/min from the third port of the four-port bottle; stirring for 12 min; stirring for 12 min; in the step (3), 110ml of double distilled water is put in, a stirring rod is inserted from the first port of the four-port bottle to stir at 4 revolutions per second, and the stirring is continuously carried out at the temperature of 35-40 ℃; slowly adding 0.6g of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder crushing until the average particle size is below 60um from the second opening of the four-opening bottle, and then dripping 4ml of high-grade pure isopropanol at a very slow speed; respectively taking 4g of FeCl2·4H2O and 3g of K2SO4To obtain 4g of FeCl2·4H2Fine powder of O and 3g of K2SO4Fine powder; slowly adding 11g of graphene oxide micro-tablets with large radial dimension from the second opening of a four-opening bottle, continuously stirring for 16min after all the graphene oxide micro-tablets are added, and respectively using FeCl from the third opening and the fourth opening of the four-opening bottle2·4H2O sieve barrel and K2SO4The sieve barrel is used for mixing the 4g of FeCl2·4H2Fine powder of O and 3g of K2SO4Sieving fine powder at a very slow speed, continuously stirring for 16min, and pouring the whole mixture into a hydrothermal reaction kettle; hydrothermal circulation reaction: and (3) putting the hydrothermal reaction kettle into a thermostat at 90 ℃ for 3h, taking out, putting the hydrothermal reaction kettle on a spin coater base, rotating for 30min at the speed of 3 r/s, then putting the hydrothermal reaction kettle back into the thermostat at 90 ℃, and repeating the hydrothermal-rotating step for at least 4 times.
Example 3
The preparation method of the electrode negative electrode material containing graphene as in embodiment 1 is characterized in that: in the step (1), the graphene microchip dispersion liquid is generated through ultrasonic stripping for more than 2 hours in absolute ethyl alcohol; supplementing solvent anhydrous ethanol of upper layer dispersion liquid to above 270ml, and high intensity ultrasonic vibrating for 5min, standing for 10s, supplementing absolute ethyl alcohol to a volume of more than 270ml, and repeating the above processes for at least 20 times until the average radial size of the graphene nanoplatelets is higher than 6um through AFM or SEM confirmation; in the step (2), a stirring rod is inserted from the first port of the four-port bottle to stir at 5 revolutions per second, and the stirring is continuously carried out at the temperature of 34-45 ℃; slowly adding 0.3-0.4 weight part of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder grinding until the average particle size is below 60um from the second opening of the four-opening bottle; dissolving 7-9 weight parts of ascorbic acid in double distilled water at 40-45 deg.C, magnetically stirring at 40-45 deg.C, and adding via dropper at 28 drops/min from the third port of the four-port bottle; stirring for 14 min; stirring for 14 min; in the step (3), 110ml of double distilled water is put in, a stirring rod is inserted from the first port of the four-port bottle to stir at 5 revolutions per second, and the stirring is continuously carried out at the temperature of 40-45 ℃; slowly adding 0.8g of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder crushing until the average particle size is below 60um from the second opening of the four-opening bottle, and then dripping 4ml of high-grade pure isopropanol at a very slow speed; 5g of FeCl were respectively taken2·4H2O and 4g of K2SO4To obtain 5g of FeCl2·4H2Fine O powder and 4g of K2SO4Fine powder; slowly adding 12g of graphene oxide micro-tablets with large radial dimension from the second opening of a four-opening bottle, continuously stirring for 18min after all the graphene oxide micro-tablets are added, and respectively using FeCl from the third opening and the fourth opening of the four-opening bottle2·4H2O sieve barrel and K2SO4The sieve barrel is used for mixing the 5g of FeCl2·4H2Fine O powder and 4g of K2SO4Sieving fine powder at a very slow speed, continuously stirring for 18min, and pouring the whole mixture into a hydrothermal reaction kettle; hydrothermal circulation reaction: and (3) putting the hydrothermal reaction kettle into a thermostat at 90 ℃ for 3h, taking out, putting the hydrothermal reaction kettle on a spin coater base, rotating for 35min at the speed of 5 r/s, putting the hydrothermal reaction kettle back into the thermostat at 90 ℃, and repeating the hydrothermal-rotating step for at least 5 times.
Example 4
A graphene-containing electrode negative electrode material prepared by the method of example 1, wherein the method comprises the following steps: the negative electrode material contains graphene with large radial dimensionMicro-flakes and Fe2O3Particles, graphene nanoplatelets of large radial dimension and Fe2O3The weight ratio of the particles is about 1: 0.174-1: 0.261, and more than 85% Fe2O3The particles exist by covering the surfaces of the graphene micro-sheets with large radial dimension, and the graphene micro-sheets with large radial dimension are mutually adjacent in pairs and can not expose Fe2O3The surface to which the particles are attached is below 80%.
The graphene nanoplatelets and Fe with large radial dimension2O3The weight ratio of the particles is between about 1:0.174 and 1:0.261, calculated from the weight of ferric chloride tetrahydrate and graphene added, since no major process components are lost and the weight ratio corresponds to the above values, reflecting that all ferric chloride is converted.
Through SEM and AFM observation, the material obtained by the method has no small graphene fragments, and the observation of an electron microscope shows that iron oxide particles which are not attached to graphene exist basically, so that the product is determined to exist by compounding more than 85% of iron oxide particles to cover the surface of a graphene microchip with a large radial size. The above condition is also certainly satisfied because the surface of each of the graphene nanoplatelets having a large radial dimension, which is adjacent to each other in pairs and does not expose the iron oxide particles to adhere to, is 80% or less, and the number of the adhered or laminated sheets is less than 10 to 15% of the total number by analyzing by an electron microscope by randomly selecting 50 or more sheets in the field of view.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.
Claims (4)
1. A preparation method of an electrode negative electrode material containing graphene is characterized by comprising the following steps:
1) preparing graphene nanoplatelets:
taking a large number of prefabricated expanded graphite sheets as raw materials, and ultrasonically stripping the raw materials in absolute ethyl alcohol for more than 1.5 hours to generate graphene microchip dispersion liquid; taking out the upper-layer dispersion liquid through ultrasonic treatment, and keeping the graphite which is not stripped in a container;
supplementing absolute ethyl alcohol serving as a solvent of the upper-layer dispersion liquid to more than 220ml, ultrasonically oscillating for 3-5min, standing for 5-10s, immediately discarding half of the upper-layer dispersion liquid, supplementing absolute ethyl alcohol to more than 220ml, and repeating the above processes for at least 15 times until AFM or SEM is used for confirming that the average radial size of the graphene nanoplatelets is higher than 5 um; all solvents are removed through rotary evaporation, and drying is carried out at normal temperature to obtain the graphene oxide micro-sheets with large radial sizes;
2) and (3) graphene nanoplatelets reduction:
taking a four-mouth bottle with the volume of more than 2L, adding 180 parts by weight of double distilled water, inserting a stirring rod from the first mouth of the four-mouth bottle, stirring at 3-10 r/s, and keeping the temperature to be 35-45 ℃ for continuous stirring;
slowly adding 0.2-0.4 weight part of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder grinding until the average particle size is below 60um from the second opening of the four-opening bottle;
slowly adding 20 parts by weight of graphene oxide micro-sheets with large radial dimension from the second port of the four-port bottle, after all the graphene oxide micro-sheets are added, dissolving 5-10 parts by weight of ascorbic acid with double-distilled water at 35-45 ℃, keeping the solution of ascorbic acid under magnetic stirring at 35-45 ℃, and adding the ascorbic acid solution from the third port of the four-port bottle by using a dropper at the speed of 20-30 drops/min until the addition is finished;
stirring for 10-15min, adding dropwise ammonia water from the third port, measuring pH value, and stopping adding ammonia water when pH value is stably higher than 7 and is kept for more than 5 min;
stirring for 10-15min, pouring out the mixture in the four-mouth bottle, removing supernatant, and continuously washing with excessive 40 ℃ absolute ethyl alcohol, double distilled water, absolute ethyl alcohol and double distilled water for 6 times to obtain fully reduced graphene oxide micro-sheets with large radial sizes;
3) graphene/Fe2O3Preparation of electrode materials
Taking a four-mouth bottle with the volume of more than 2L, putting 100-120ml double distilled water, inserting a stirring rod from the first mouth of the four-mouth bottle, stirring at 3-10 r/s, and keeping the temperature to be 35-45 ℃ for continuous stirring;
slowly adding 0.5-1g of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder crushing until the average particle size is below 60um from the second opening of the four-opening bottle, and dripping 3-5ml of super-grade pure isopropanol;
respectively taking 4-5g of FeCl2·4H2O and 3-4g of K2SO4Respectively grinding for more than 2h by using a mortar to ensure that the particle diameters of all particles are less than 300nm to obtain 4-5g of FeCl2·4H2Fine O powder and 3-4g of K2SO4Fine powder, respectively adding FeCl2·4H2O sieve barrel and K2SO4The lower surface of the sieve barrel is coated with microporous resin film with the aperture of 500-800 nm;
slowly adding 10-12g of graphene oxide micro-tablets with large radial dimension from the second opening of a four-opening bottle, continuously stirring for 15-20min after all the graphene oxide micro-tablets are added, and respectively using FeCl from the third opening and the fourth opening of the four-opening bottle2·4H2O sieve barrel and K2SO4The sieve barrel is used for mixing the 4-5g of FeCl2·4H2Fine O powder and 3-4g of K2SO4Sieving fine powder, adding for no less than 15min, continuously stirring for 15-20min, and pouring the mixture into a hydrothermal reaction kettle;
hydrothermal circulation reaction: placing the hydrothermal reaction kettle into a thermostat at 90 ℃ for 3h, taking out, placing on a spin coater base, rotating at the speed of 2-5 r/s for 25-35min, placing back into the thermostat at 90 ℃, and repeating the hydrothermal-rotating steps for at least 3 times;
and pouring out the mixture in the hydrothermal reaction kettle, removing supernatant, continuously washing with excessive 40 ℃ absolute ethyl alcohol, double distilled water, absolute ethyl alcohol and double distilled water for 6 times to obtain a filter cake, spreading the filter cake in a container under a flowing nitrogen environment at the temperature of 30-40 ℃, and drying overnight to obtain the composite negative electrode material.
2. The method for preparing the electrode negative electrode material containing graphene according to claim 1, wherein the method comprises the following steps:
in the step (1), the graphene microchip dispersion liquid is generated through ultrasonic stripping for more than 1.5h in absolute ethyl alcohol; supplementing absolute ethyl alcohol serving as a solvent of the upper-layer dispersion liquid to more than 220ml, ultrasonically oscillating for 4min, standing for 8s, supplementing absolute ethyl alcohol to the volume of more than 220ml, and repeating the above processes for at least 15 times until AFM or SEM is used for confirming that the average radial size of the graphene nanoplatelets is higher than 5 um;
in the step (2), a stirring rod is inserted from the first port of the four-port bottle to stir at 4 revolutions per second, and the stirring is continuously carried out at the temperature of 35-40 ℃; slowly adding 0.2-0.3 weight part of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder grinding until the average particle size is below 60um from the second opening of the four-opening bottle; dissolving 5-7 weight parts of ascorbic acid in double distilled water at 35-40 deg.C, magnetically stirring at 35-40 deg.C, and adding via dropper at 24 drops/min from the third port of the four-port bottle; stirring for 12 min; stirring for 12 min;
in the step (3), 110ml of double distilled water is put in, a stirring rod is inserted from the first port of the four-port bottle to stir at 4 revolutions per second, and the stirring is continuously carried out at the temperature of 35-40 ℃;
slowly adding 0.6g of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder crushing until the average particle size is below 60um from the second opening of the four-opening bottle, and then dripping 4ml of super-grade pure isopropanol;
respectively taking 4g of FeCl2·4H2O and 3g of K2SO4To obtain 4g of FeCl2·4H2Fine powder of O and 3g of K2SO4Fine powder;
slowly adding 11g of graphene oxide micro-tablets with large radial dimension from the second opening of a four-opening bottle, continuously stirring for 16min after all the graphene oxide micro-tablets are added, and respectively using FeCl from the third opening and the fourth opening of the four-opening bottle2·4H2O sieve barrel and K2SO4The sieve barrel is used for mixing the 4g of FeCl2·4H2Fine powder of O and 3g of K2SO4Sieving fine powder, continuously stirring for 16min, and pouring the whole mixture into a hydrothermal reaction kettle;
hydrothermal circulation reaction: and (3) putting the hydrothermal reaction kettle into a thermostat at 90 ℃ for 3h, taking out, putting the hydrothermal reaction kettle on a spin coater base, rotating for 30min at the speed of 3 r/s, then putting the hydrothermal reaction kettle back into the thermostat at 90 ℃, and repeating the hydrothermal-rotating step for at least 4 times.
3. The method for preparing the electrode negative electrode material containing graphene according to claim 1, wherein the method comprises the following steps:
in the step (1), the graphene microchip dispersion liquid is generated through ultrasonic stripping for more than 2 hours in absolute ethyl alcohol; supplementing absolute ethyl alcohol serving as a solvent of the upper-layer dispersion liquid to more than 270ml, ultrasonically oscillating for 5min, standing for 10s, supplementing absolute ethyl alcohol to more than 270ml, and repeating the above processes for at least 20 times until AFM or SEM is used for confirming that the average radial size of the graphene nanoplatelets is higher than 6 um;
in the step (2), a stirring rod is inserted from the first port of the four-port bottle to stir at 5 revolutions per second, and the stirring is continuously carried out at the temperature of 34-45 ℃; slowly adding 0.3-0.4 weight part of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder grinding until the average particle size is below 60um from the second opening of the four-opening bottle; dissolving 7-9 weight parts of ascorbic acid in double distilled water at 40-45 deg.C, magnetically stirring at 40-45 deg.C, and adding via dropper at 28 drops/min from the third port of the four-port bottle; stirring for 14 min; stirring for 14 min;
in the step (3), 110ml of double distilled water is put in, a stirring rod is inserted from the first port of the four-port bottle to stir at 5 revolutions per second, and the stirring is continuously carried out at the temperature of 40-45 ℃;
slowly adding 0.8g of PVA (polyvinyl alcohol) ultrafine powder which is subjected to repeated freeze-drying powder crushing until the average particle size is below 60um from the second opening of the four-opening bottle, and dripping 4ml of super-pure isopropanol;
5g of FeCl were respectively taken2·4H2O and 4g of K2SO4To obtain 5g of FeCl2·4H2Fine O powder and 4g of K2SO4Fine powder;
slowly adding 12g of graphene oxide micro-tablets with large radial dimension from the second opening of a four-opening bottle, continuously stirring for 18min after all the graphene oxide micro-tablets are added, and respectively using FeCl from the third opening and the fourth opening of the four-opening bottle2·4H2O sieve barrel and K2SO4The sieve barrel is used for mixing the 5g of FeCl2·4H2Fine O powder and 4g of K2SO4Sieving fine powder, continuously stirring for 18min, and pouring the whole mixture into a hydrothermal reaction kettle;
hydrothermal circulation reaction: and (3) putting the hydrothermal reaction kettle into a thermostat at 90 ℃ for 3h, taking out, putting the hydrothermal reaction kettle on a spin coater base, rotating for 35min at the speed of 5 r/s, putting the hydrothermal reaction kettle back into the thermostat at 90 ℃, and repeating the hydrothermal-rotating step for at least 5 times.
4. A graphene-containing electrode negative electrode material prepared by the method for preparing a graphene-containing electrode negative electrode material according to claim 1, characterized in that:
the negative electrode material contains graphene micro-sheets with large radial sizes and Fe2O3Particles, graphene nanoplatelets of large radial dimension and Fe2O3The weight ratio of the particles is between 1:0.174 and 1:0.261, and more than 85 percent of Fe2O3The particles exist by covering the surfaces of the graphene micro-sheets with large radial dimension, and the graphene micro-sheets with large radial dimension are mutually adjacent in pairs and can not expose Fe2O3The surface to which the particles are attached is below 80%.
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