CN107611346B - flexible electrode material of lithium ion battery, preparation method of flexible electrode material and lithium ion battery - Google Patents
flexible electrode material of lithium ion battery, preparation method of flexible electrode material and lithium ion battery Download PDFInfo
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Abstract
the invention relates to the field of batteries, and discloses a flexible electrode material of a lithium ion battery, a preparation method of the flexible electrode material and the lithium ion battery, wherein the preparation method of the flexible electrode material of the lithium ion battery comprises the following steps: (1) dissolving a carbon-containing polymer in a solvent to obtain a solution; (2) mixing the main body material and/or the precursor of the main body material with the solution to obtain spinning solution, and then performing electrostatic spinning to obtain a spinning substance; (3) sequentially carrying out pretreatment and heat treatment on the spinning substance to obtain a flexible electrode material of the lithium ion battery; the host material contains at least one of polyanionic phosphate, silicate, lithium-rich material, ternary material, transition metal oxide, lithium-containing metal oxide and silicon. The flexible electrode material provided by the invention has the advantages of simple preparation method, strong universality and low cost, and has higher charge-discharge specific capacity and cycle reversibility when being used in a lithium ion battery.
Description
Technical Field
the invention relates to the field of batteries, in particular to a flexible electrode material of a lithium ion battery, a preparation method of the flexible electrode material and the lithium ion battery.
Background
The flexible electrode material is a popular direction in current research, and the flexible material is increasingly hot-held due to the advantages of being bendable, convenient to carry and the like, so that the flexible electrode material has a huge application prospect, such as curved surface display screens, intelligent clothes, electronic skins, medical appliances and the like. The development of flexible battery materials matched with the flexible battery materials is also concerned. Currently, lithium ion batteries are considered one of the most desirable chemical power sources due to their higher energy and power densities. Conventional lithium ion batteries tend to have large volumes and heavy weights, because a copper foil or an aluminum foil is often required as a current collector for a general electrode material, a binder is required to attach an active material to the current collector, and an additional conductive agent is required, which greatly increases the weight of the battery. In addition, if the hard pole piece is soaked in the electrolyte and is bent again, the electrode material is easy to fall off, the fallen electrode is likely to cause short circuit of the electrode, and the cycle life of the electrode is greatly reduced. The anode, the cathode and the diaphragm of the flexible electrode material are required to be flexible, and the flexible electrode material can be directly used for manufacturing the electrode material. This greatly reduces the overall weight and cost of the battery because no additional current collectors and binders need to be added. However, flexible lithium ion batteries also face challenges to achieve the same or practical results as current commercial batteries, such as (1) the electrodes are flexible and bendable; (2) the current collector, the binder and the conductive carbon are not required to be added; (3) the electrode material needs to have good conductivity (4) and the preparation process is simple and efficient. At present, the method for manufacturing the flexible electrode material mostly adopts graphene or carbon nanotubes as a support main body, the manufacturing process is complex, the cost is high, and the selectivity to the main body material is high.
In order to solve the above problems, it is important to find a method for effectively improving the conductivity of the electrode material without using a hard current collector. The specific carbon nanofiber framework prepared by the electrostatic spinning method can provide a good conductive network for a main material, so that the carbon nanofiber framework can serve as a current collector. Although there are reports on the preparation of flexible electrodes by electrostatic spinning at home and abroad, for example, in the Nano Lett.2016,16,3321-3328, Liu et al, the preparation of MnFe by electrostatic spinning is adopted2O4The @ C nanofiber flexible electrode is applied to a sodium ion battery negative electrode material, but the flexible material is formed in situChemically synthesized, MnFe2O4existing in the nano-fiber carbon tube, the structure of the nano-fiber is easy to damage in the high-temperature treatment process, and the synthesis efficiency is low, so that the industrial application is difficult. Xiong et al in Scientific reports 2015,5,9254 also prepared MoS by electrospinning2the/C flexible film is used for a sodium ion battery cathode material, the document adopts Polyacrylonitrile (PAN) as a high polymer to synthesize a one-dimensional carbon nano tube material, the used spinning solvent PAN requires that a solvent is dimethylformamide, the water-insoluble property of the PAN requires that a raw material for preparing a main body material is soluble in the dimethylformamide, so that great limitation is caused to the selection of the raw material, difficulty is caused to the large-scale industrial production, and the MoS flexible film is also synthesized by an in-situ chemical method2Present in carbon nano-fibre tubes, also suffer from the above-mentioned drawbacks. N-doped one-dimensional CuCo synthesized by coke Li Fang topic group of southern Kao university by adopting electrostatic spinning method2O4Thin film, then used for secondary battery negative electrode material at 1000mA g-1Under the current density of (1), 314mA h g is still obtained after 1000 cycles-1Reversible capacity of (2), even at 5000mA h g-1Still has 296mA h g at high current density-1The reversible capacity of (a). However, the flexible material is synthesized by an in-situ chemical method, CuCo2O4Present in carbon nano-fibre tubes, also suffer from the above-mentioned drawbacks.
Therefore, the method for preparing the flexible electrode material of the lithium ion battery, which is low in cost, high in efficiency and universal, has important research significance.
Disclosure of Invention
the invention aims to overcome the defects that a nanofiber structure in a flexible electrode material is easy to damage, the in-situ synthesis efficiency is low and the conditions are harsh in the prior art, and provides a flexible electrode material of a lithium ion battery, a preparation method of the flexible electrode material and the lithium ion battery.
the inventor of the present invention finds, in the course of research, that, in the prior art, when the flexible electrode is prepared by an electrostatic spinning method, an in-situ chemical synthesis method is mainly used (i.e., raw materials for preparing the flexible electrode material and a spinning solution are mixed together to carry out electrostatic spinning), and the flexible electrode material synthesized by the in-situ chemical synthesis method mainly exists in a carbon tube of a nanofiber, and the flexible electrode material with the structure is easy to damage the structure of the nanofiber in a high-temperature treatment process, and has low synthesis efficiency. In the course of further research, the inventors of the present invention found that, in a flexible electrode material obtained by electrospinning a spinning solution obtained by mixing a lithium ion battery electrode host material and/or a precursor of the lithium ion battery electrode host material with a solution (containing a carbon-containing polymer and a solvent), host material particles are distributed among a plurality of carbon nanofibers and do not exist in carbon tubes of the nanofibers. The structure can not damage the nanofiber structure in the high-temperature treatment process, and the electrode assembled by adopting the electrode material can also keep the stability of the carbon nanofiber structure in the de-intercalation process.
Based on this, the invention provides a flexible electrode material for a lithium ion battery, which comprises: a carbon nanofiber network skeleton composed of a plurality of carbon nanofibers, and host material particles distributed among the plurality of carbon nanofibers; the host material particles contain at least one of polyanionic phosphate, silicate, lithium-rich material, ternary material, transition metal oxide, lithium-containing metal oxide and silicon;
The polyanionic phosphate is selected from LiFe1-yMyPO4And/or Li3V2-xMx(PO4)3M is at least one of Mg, Ni and Ti, x is more than or equal to 0 and less than or equal to 2, and y is more than or equal to 0 and less than or equal to 1;
The silicate is Li2RSiO4R is Fe and/or Mn;
The lithium-rich material is Li1.2Ni0.2Mn0.6O2；
the ternary material is LiNiaCobMncO2A is more than 0 and less than 1, b is more than 0 and less than 1, c is more than 0 and less than 1, and a + b +c＝1；
the transition metal oxide is Fe3O4And/or Co3O4；
The lithium-containing metal oxide is selected from LiCoO2、LiMn2O4、Li4Ti5O12And Li2TiO3at least one of (1).
the invention provides a preparation method of a flexible electrode material of a lithium ion battery, which comprises the following steps:
(1) dissolving a carbon-containing polymer in a solvent to obtain a solution;
(2) Mixing the main body material and/or the precursor of the main body material with the solution to obtain spinning solution, and then performing electrostatic spinning to obtain a spinning substance;
(3) Sequentially carrying out pretreatment and heat treatment on the spinning substance to obtain a flexible electrode material of the lithium ion battery;
the main body material contains at least one of polyanion phosphate, silicate, lithium-rich material, ternary material, transition metal oxide, lithium-containing metal oxide and silicon;
The polyanionic phosphate is selected from LiFe1-yMyPO4And/or Li3V2-xMx(PO4)3m is at least one of Mg, Ni and Ti, x is more than or equal to 0 and less than or equal to 2, and y is more than or equal to 0 and less than or equal to 1;
The silicate is Li2RSiO4R is Fe and/or Mn;
The lithium-rich material is Li1.2Ni0.2Mn0.6O2；
the ternary material is LiNiaCobMncO2A is more than 0 and less than 1, b is more than 0 and less than 1, c is more than 0 and less than 1, and a + b + c is 1;
The transition metal oxide is Fe3O4and/or Co3O4；
The lithium-containing metal oxide is selected from LiCoO2、LiMn2O4、Li4Ti5O12And Li2TiO3At least one of (1).
The invention also provides the flexible electrode material of the lithium ion battery prepared by the method.
the invention also provides a lithium ion battery, and the electrode material of the lithium ion battery comprises the electrode material.
The flexible electrode material of the lithium ion battery provided by the invention has the following advantages:
(1) according to the flexible electrode material prepared by the electrostatic spinning method, the main material particles are distributed among the plurality of carbon nano fibers, the structure is favorable for increasing the conductivity of the main material, and the flexible electrode material is assembled into a lithium ion battery, so that the transmission of lithium ions and the infiltration of electrolyte are very favorable;
(2) the flexible electrode material provided by the invention does not need a current collector and a binder, does not need a conductive additive, and can be directly used for assembling a lithium ion battery;
(3) The flexible electrode material provided by the invention has the characteristic of light weight because a current collector is not needed, can greatly reduce the weight of the battery, improves the energy density of the battery, and has great practical prospect;
(4) the method comprises the steps of preparing a main material and/or a precursor of the main material, dispersing the main material and/or the precursor into a solution to obtain a spinning solution, and spinning, wherein the method is almost suitable for preparing any lithium ion battery anode and cathode flexible material because the dissolution of an active material is not limited by a spinning solvent;
(5) Compared with the conventional lithium ion battery electrode material synthesized by a solid phase method, a sol-gel method, a coprecipitation method and the like, the flexible electrode material of the flexible lithium ion battery prepared by the electrostatic spinning method can realize the large-rate charge and discharge and long cycle performance of the battery, and has good application value.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
FIG. 1 is an SEM photograph of a flexible electrode material S1 obtained in example 1 of the present invention;
Fig. 2 is an SEM image of the flexible electrode material D1 prepared in comparative example 1 of the present invention.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The invention provides a flexible electrode material of a lithium ion battery, which comprises the following components: a carbon nanofiber network skeleton composed of a plurality of carbon nanofibers, and host material particles distributed among the plurality of carbon nanofibers; the host material particles contain at least one of polyanionic phosphate, silicate, lithium-rich material, ternary material, transition metal oxide, lithium-containing metal oxide and silicon;
the polyanionic phosphate is selected from LiFe1-yMyPO4And/or Li3V2-xMx(PO4)3M is at least one of Mg, Ni and Ti, x is more than or equal to 0 and less than or equal to 2, and y is more than or equal to 0 and less than or equal to 1;
the silicate is Li2RSiO4R is Fe and/or Mn;
The lithium-rich material is Li1.2Ni0.2Mn0.6O2；
The ternary material is LiNiaCobMncO2A is more than 0 and less than 1, b is more than 0 and less than 1, c is more than 0 and less than 1, and a + b + c is 1;
The transition metal oxide is Fe3O4And/or Co3O4；
The lithium-containing metal oxide is selected from LiCoO2、LiMn2O4、Li4Ti5O12and Li2TiO3At least one of (1).
As shown in fig. 1, the particles of the main material in the flexible electrode material for a lithium ion battery provided by the present invention are distributed among a plurality of carbon nanofibers, whereas in the flexible electrode material provided by the prior art, the particles of the main material are located inside one carbon nanofiber, the particle size of the particles of the main material is limited by the diameter of the carbon nanofiber, and the particle size is smaller, and the flexible electrode material provided by the present invention has no particular limitation on the size of the particles of the main material; in addition, the desorption of ions in the main material particles of the flexible electrode material provided by the prior art can damage the carbon nanofiber structure, thereby affecting the overall stability of the flexible electrode material of the lithium ion battery.
in order to further improve the electrochemical performance of the flexible electrode material provided by the invention, the average particle size of the host material particles is preferably 20nm to 0.5mm, and more preferably 50nm to 5 μm.
In the invention, the average particle size is counted by a field emission Scanning Electron Microscope (SEM), and is measured by measuring the longest diameter of the main material particles in a shot electron microscope picture, measuring for multiple times and then averaging.
According to the flexible electrode material provided by the invention, the diameter of the carbon nanofiber is preferably 50nm-900nm, more preferably 100nm-500nm, and even more preferably 100nm-300 nm. The diameter of the carbon nanofiber can be counted by a field emission Scanning Electron Microscope (SEM), and the diameter of the carbon nanofiber can be measured by measuring the maximum diameter of the carbon nanofiber in a shot electron microscope picture, measuring for multiple times and then averaging.
the selection range of the content of the carbon nanofibers and the content of the host material particles are wide, and in order to further improve the electrochemical performance of the flexible electrode material, the content of the host material particles is preferably 40 to 90 wt%, the content of the carbon nanofibers is 10 to 60 wt%, the content of the host material particles is more preferably 40 to 80 wt%, and the content of the carbon nanofibers is 20 to 60 wt%.
The contents of the carbon nanofibers and the particles of the main body material in the flexible electrode material can be measured by a thermogravimetric differential thermal (TG-DTA) method, the thermogravimetric differential thermal curve of the flexible electrode material is measured in the air atmosphere, and then the contents of the main body material and the carbon nanofibers are calculated according to the weight loss curve.
The selection range of the types of the host material particles is wide, the host material particles can be various host materials conventionally used in the field of lithium ion batteries, and can be a positive electrode host material or a negative electrode host material. Based on the disclosure of the present specification, a person skilled in the art is fully able to determine which lithium ion battery electrode host materials to use.
According to a preferred embodiment of the present invention, the ternary material is LiNi0.8Co0.1Mn0.1O2、LiNi0.6Co0.2Mn0.2O2、LiNi0.4Co0.3Mn0.3O2、LiNi0.5Co0.3Mn0.2O2And LiNi1/3Co1/3Mn1/3O2At least one of (1).
According to a preferred embodiment of the present invention, the host material particles comprise LiFePO4、Li3V2(PO4)3、LiCoO2、LiMn2O4、Li2FeSiO4、Li2MnSiO4、Li1.2Ni0.2Mn0.6O2、LiNi0.8Co0.1Mn0.1O2、Li4Ti5O12Si and Fe3O4At least one of (1).
The thickness of the flexible electrode material for the lithium ion battery is not particularly limited, and in order to further improve the electrochemical performance of the flexible electrode material for the lithium ion battery, the thickness of the flexible electrode material for the lithium ion battery is preferably 0.01 to 5mm, more preferably 0.1 to 3mm, and even more preferably 0.5 to 1 mm.
The invention also provides a preparation method of the flexible electrode material of the lithium ion battery, which comprises the following steps:
(1) Dissolving a carbon-containing polymer in a solvent to obtain a solution;
(2) Mixing the main body material and/or the precursor of the main body material with the solution to obtain spinning solution, and then performing electrostatic spinning to obtain a spinning substance;
(3) Sequentially carrying out pretreatment and heat treatment on the spinning substance to obtain a flexible electrode material of the lithium ion battery;
The main body material contains at least one of polyanion phosphate, silicate, lithium-rich material, ternary material, transition metal oxide, lithium-containing metal oxide and silicon;
the polyanionic phosphate is selected from LiFe1-yMyPO4and/or Li3V2-xMx(PO4)3M is at least one of Mg, Ni and Ti, x is more than or equal to 0 and less than or equal to 2, and y is more than or equal to 0 and less than or equal to 1;
The silicate is Li2RSiO4R is Fe and/or Mn;
The lithium-rich material is Li1.2Ni0.2Mn0.6O2；
The ternary material is LiNiaCobMncO2A is more than 0 and less than 1, b is more than 0 and less than 1, c is more than 0 and less than 1, and a + b + c is 1;
the transition metal oxide is Fe3O4And/or Co3O4；
the lithium-containing metal oxide is selected from LiCoO2、LiMn2O4、Li4Ti5O12and Li2TiO3At least one of (1).
The present invention does not particularly require the mass content of the solvent and the carbon-containing polymer in the solution of step (1) as long as the carbon-containing polymer can be completely dissolved, and preferably, the content of the carbon-containing polymer is preferably 5 to 20% by weight, more preferably 5 to 15% by weight, and still more preferably 6.5 to 15% by weight, based on the total weight of the solution.
According to a preferred embodiment of the present invention, the carbonaceous polymer is selected from the group consisting of high polymers having a number average molecular weight of 10000 to 1500000, and more preferably from the group consisting of high polymers having a number average molecular weight of 16000 to 1300000.
In the present invention, as long as a high polymer that can be used for electrospinning can be used in the present invention, the carbon-containing polymer is preferably at least one selected from the group consisting of polyethylene oxide, polyvinylidene fluoride, polymethacrylate, polyethylene oxide, polyvinylpyrrolidone, polyvinylcarbazole, polybenzimidazole, polyethylene terephthalate, polymethyl methacrylate, polystyrene, polyurethane, polyvinyl alcohol, polylactic acid, polyacrylonitrile, and polyvinyl chloride, and more preferably at least one selected from the group consisting of polyacrylonitrile, polyethylene oxide, polyvinylpyrrolidone, and polyvinyl alcohol.
The present invention has a wide range of selection of the solvent, and preferably, the solvent is at least one selected from the group consisting of dimethylformamide, dimethylacetamide, dimethylsulfoxide, ethylene carbonate, and water.
the solvent of the present invention may be any solvent that can dissolve the carbon-containing compound, and when the carbon-containing compound is a specific substance, those skilled in the art can select an appropriate solvent according to the disclosure of the present specification. The invention will not be described one by one here.
According to the method provided by the present invention, in the step (2), the host material may be mixed with the solution to obtain the spinning solution, and then the spinning solution may be electrostatically spun, or a precursor of the host material may be mixed with the solution to obtain the spinning solution, and then the spinning solution may be electrostatically spun, or the host material and the precursor of the host material may be second mixed with the solution to obtain the spinning solution, and then the spinning solution may be electrostatically spun, and the present invention is not particularly limited thereto.
The precursor of the host material according to the present invention is not a raw material for synthesizing the host material, but a substance that has been converted into the host material under the heat treatment conditions described in step (3) by a certain interaction between the raw materials.
According to the method provided by the invention, the selection range of the dosage of the main material and/or the precursor of the main material and the solution is wide, and preferably, the ratio of the mass of the main material and/or the precursor of the main material to the mass of the solution calculated by the carbon-containing polymer is (0.1-2): 1, preferably (0.3-1.5): 1.
When the step (2) is to mix the host material and the precursor of the host material with the solution, the ratio of the mass of the host material and/or the precursor of the host material to the mass of the solution in terms of the carbon-containing polymer means the ratio of the mass of the sum of the host material and the precursor of the host material to the mass of the solution in terms of the carbon-containing polymer.
In the present invention, the particle size of the host material and the precursor of the host material is not particularly limited as long as electrostatic spinning is possible.
According to the method provided by the invention, the particle size of the main material is preferably not more than 1mm, more preferably not more than 0.5mm, and still more preferably 0.15-5 μm.
According to the method provided by the invention, the particle size of the precursor of the host material is preferably not more than 1mm, more preferably not more than 0.5mm, and still more preferably 0.15-5 μm.
In the present invention, the method for obtaining the host material and the precursor of the host material having the above particle size is not particularly limited, and the host material and the precursor of the host material may be ground in at least one step of the production process, or may be ground after the host material and/or the precursor thereof are produced. In addition, certain host materials and/or precursors of host materials may be prepared with products having particle sizes that directly meet the particle size requirements of the present invention for the host materials and/or precursors of host materials, and therefore, may not include a milling process. The person skilled in the art will be able to make a suitable choice as to whether grinding is required and in which particular step grinding is carried out, depending on the different host materials.
According to the method provided by the present invention, the selection of the type of the host material is as described above, and is not described herein again.
The present invention is not particularly limited to the specific embodiment of the mixing in step (2), and preferably, the mixing includes: and (3) contacting the main material and/or the precursor of the main material with the solution, and then sequentially carrying out ultrasonic dispersion and magnetic stirring. The mode of combining ultrasonic dispersion and magnetic stirring is more favorable for dissolving the main body material and/or the precursor of the main body material, and further more favorable for improving the electrochemical performance of the flexible electrode material of the lithium ion battery.
According to the method provided by the invention, the ultrasonic dispersion can be carried out according to the conventional technical means in the field, and preferably, the frequency of the ultrasonic dispersion is 40kHz-100kHz, and the time is 0.5-6 h.
according to the method provided by the invention, the magnetic stirring can be carried out according to the conventional technical means in the field, preferably, the rotating speed of the magnetic stirring is 150rpm-1000rpm, and the time is 1-20h, and further preferably, the rotating speed of the magnetic stirring is 400rpm-600rpm, and the time is 4-10 h.
According to a preferred embodiment of the present invention, the conditions of the electrospinning include: the voltage is 10kV-30kV, and more preferably 15kV-22 kV; the distance between the filament outlet and the receiver is 10cm-25cm, and the preferred distance is 15cm-20 cm; the advancing speed is 0.01mm/min-0.5mm/min, and more preferably 0.08mm/min-0.2 mm/min.
According to the method provided by the invention, the spinning substance can be obtained by stripping the product obtained in the step (2) from a receiver (which can be aluminum foil).
According to the method provided by the invention, preferably, the pretreatment conditions comprise: the temperature is 100-500 deg.C, preferably 250-350 deg.C, and the time is 30-300min, preferably 120-300 min.
According to the method provided by the present invention, preferably, the heat treatment conditions include: under inert atmosphere, the temperature is 300-1600 ℃, more preferably 450-900 ℃, and the time is 1-12h, more preferably 2-12 h.
The inert atmosphere is not particularly limited in the present invention, and may be provided by one or more of nitrogen, helium, argon and neon, and preferably argon.
The invention also provides the flexible electrode material of the lithium ion battery prepared by the method.
The invention also provides a lithium ion battery, wherein the electrode material of the lithium ion battery comprises the electrode material.
according to the present invention, the lithium ion battery may be a full battery or a half battery. When the electrode material is used for testing the electrical property of the battery electrode material, a half battery is adopted for testing. The half-cell may further include a counter electrode, a separator, and an electrolyte. Wherein, the counter electrode is a metal lithium sheet. The separator is used to prevent the short circuit of the battery caused by the direct contact between the positive electrode and the negative electrode, and for example, a polypropylene porous membrane Celgard2400 can be used. Wherein the electrolyte can be electrolyte conventionally used in the art, such as LiPF6And (3) an electrolyte.
the lithium ion battery can be assembled in the form of a button cell in a glove box filled with inert gas.
By adopting the flexible electrode material, the lithium ion battery with higher reversible discharge specific capacity and better stability can be obtained, and a current collector, a conductive additive and a binder are not needed.
The present invention will be described in detail below by way of examples.
In the following examples and comparative examples, the electrospinning apparatus was purchased from the national institute of science and technology development, GmbH, Yongkang, Beijing, under the type Elite series;
SEM analysis was performed using a field emission scanning electron microscope (model S-4800, available from Hitachi, Japan);
assembling the battery by adopting a Michelonan argon protection glove box;
the magnetic stirrer is a German IKA topolinio magnetic stirrer;
The diaphragm is a polypropylene porous membrane Celgard 2400;
The diameter of the carbon nanofiber is counted by adopting a field emission Scanning Electron Microscope (SEM), and is measured by measuring the maximum diameter of the carbon nanofiber in a shot electron microscope picture, measuring for multiple times and then taking an average value.
The average particle size of the main material particles is counted by a field emission Scanning Electron Microscope (SEM), and is measured by measuring the longest diameter of the main material particles in a shot electron microscope picture, measuring for multiple times and then taking an average value;
In the flexible electrode material, the contents of carbon nanofibers and particles of a main body material are measured by adopting a thermogravimetric differential thermal (TG-DTA) method, a thermogravimetric differential thermal curve of the flexible electrode material is measured in the air atmosphere, and then the contents of the main body material and the carbon nanofibers are calculated according to a weight loss curve.
Example 1
polyanionic phosphates LiFePO4and preparing the flexible electrode material.
(1) 0.7389g of Li2CO3，4.1986g Fe(CH3COO)2·2H2O and 2.3006g NH4H2PO4Adding 15mL of acetone after mixing, carrying out ball milling for 10h, sealing high-purity argon in a ball milling tank to prevent the materials from being oxidized to obtain a mixed material, carrying out vacuum drying on the mixed material at 70 ℃, then carrying out grinding, and then calcining for 10h at 300 ℃ in a tubular furnace of high-purity argon to obtain LiFePO4Precursor powder (particle size about 2 μm);
(2) Weighing 1g of polyacrylonitrile (PAN, the number average molecular weight of 150000, the same below) powder, dissolving in Dimethylformamide (DMF), and stirring to form a solution with a mass content of 7.1 wt%;
(3) weighing 1g of LiFePO obtained in the step (1)4precursor powder is added into the solution, the mixture is uniformly stirred, then ultrasonic dispersion (40kHz, 2 hours) and magnetic stirring (1000rpm and 20 hours) are sequentially carried out to obtain spinning solution, the obtained spinning solution is filled into a 10ml disposable injector and is put into an electrostatic spinning instrument for electrostatic spinning, a circle of aluminum foil is wound on a receiving roller to receive nano-fibers obtained by spinning, and the electrostatic spinning conditions comprise that: the advancing speed is 0.08mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 15cm, the spinning voltage is 15kV, the obtained spinning material is taken off from an aluminum foil, the pretreatment is carried out for 2h at 250 ℃ in a muffle furnace, and then the heat treatment is carried out for 8h at 600 ℃ in the argon atmosphere, thus obtaining the flexible electrode material S1. The thickness of the prepared flexible electrode material S1 was 1 mm.
SEM analysis of the flexible electrode material S1 was carried out, and the obtained SEM image is shown in FIG. 1As can be seen from FIG. 1, LiFePO4The particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S1, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Comparative example 1
0.7389g of Li2CO3，4.1986g Fe(CH3COO)2·2H2O、2.3006g NH4H2PO4And 15mL of acetone were mixed, denoted as solution a, 1g of polyacrylonitrile (PAN, number average molecular weight of 150000) powder was dissolved in Dimethylformamide (DMF), stirred to form a solution having a mass content of 7.1 wt%, denoted as solution B, solution a was added to solution B, stirred uniformly, and this was taken as a spinning solution, followed by electrostatic spinning, pretreatment, and heat treatment as in example 1, to obtain a flexible electrode material D1.
SEM analysis of the flexible electrode material D1 is carried out, and the obtained SEM image is shown in FIG. 2, and from the SEM image, LiFePO serving as a main material can be seen from the SEM image4The particles are positioned inside the carbon tube of the carbon nano fiber and present a one-dimensional structure.
The diameter of the carbon nanofibers of the flexible electrode material D1, the average particle size of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are shown in table 1, and since the particle size of the host material particles is limited to the carbon nanofibers, the particle size of the host material particles is significantly smaller than that of the flexible electrode material S1 obtained in example 1.
example 2
Polyanionic phosphates Li3V2(PO4)3and preparing the flexible electrode material.
(1) 0.7664g of LiOH, 2.3396g of NH4VO3，3.4506g NH4H2PO4And 4.2028g of citric acid in a 250mL beaker with deionized water (70g) and stirring at 80 ℃ until sol is formed, then vacuum drying at 80 ℃ for 12h to form dry gel, then grinding the dry gel, and presintering at 350 ℃ for 3h in a muffle furnace to obtain Li3V2(PO4)3Precursor powder (particle size about 5 μm);
(2) Weighing 2g of polyvinylpyrrolidone (PVP, with the number average molecular weight of 1300000, the same below) powder, dissolving in distilled water, and stirring to form a solution with the mass content of 10 wt%;
(3) Weighing 1.5g of Li obtained in step (1)3V2(PO4)3precursor powder is added into the solution, the mixture is uniformly stirred, then ultrasonic dispersion (100kHz, 2 hours) and magnetic stirring (500rpm, 10 hours) are sequentially carried out to obtain spinning solution, the obtained spinning solution is filled into a 10ml disposable injector and is put into an electrostatic spinning instrument for electrostatic spinning, a circle of aluminum foil is wound on a receiving roller to receive nano-fibers obtained by spinning, and the electrostatic spinning conditions comprise that: the advancing speed is 0.2mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 20cm, the spinning voltage is 20kV, the obtained spinning material is taken off from the aluminum foil, the pretreatment is carried out for 5h at 350 ℃ in a muffle furnace, and then the heat treatment is carried out for 6h at 800 ℃ in the argon atmosphere, thus obtaining the flexible electrode material S2. The thickness of the prepared flexible electrode material S2 was 1 mm.
SEM analysis is carried out on the flexible electrode material S2, and the SEM analysis result shows that Li3V2(PO4)3The particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S2, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 3
Lithium-containing metal oxide LiCoO2And preparing the flexible electrode material.
(1) 2.0404g LiCH3COO·2H2o and 4.9816g Co (CH)3COO)2·4H2Dissolving O in 20ml deionized water, magnetically stirring at room temperature for 1h, freeze-drying the obtained mixture for 10h at (-80 ℃), grinding to obtain dry solid powder, heating the solid powder to 800 ℃ at a heating rate of 10 ℃/min in a muffle furnace in an air atmosphere, and calcining for 2h to obtain LiCoO2powder (particle size about 1 μm);
(2) weighing 1.5g polyacrylonitrile (PAN, number average molecular weight 150000, the same below) and dissolving in DMF solution, stirring to form 11.5 wt% solution;
(3) Weighing 0.5g of LiCoO obtained in step (1)2Adding powder into the solution, uniformly stirring, then sequentially performing ultrasonic dispersion (100Hz and 2h) and magnetic stirring (700rpm and 8h) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable syringe, putting the syringe into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive the nano-fibers obtained by spinning, wherein the electrostatic spinning conditions comprise that: the advancing speed is 0.08mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 18cm, the spinning voltage is 20kV, the obtained spinning material is taken off from the aluminum foil, the pretreatment is carried out for 2h at 280 ℃ in a muffle furnace, and then the heat treatment is carried out for 4h at 600 ℃ in the argon atmosphere, thus obtaining the flexible electrode material S3. The thickness of the prepared flexible electrode material S3 was 1.5 mm.
SEM analysis is carried out on the flexible electrode material S3, and the result of the SEM analysis shows that LiCoO2the particles are distributed among the plurality of carbon nanofibers.
the diameter of the carbon nanofibers of the flexible electrode material S3, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 4
according to the method of example 3, except that, in step (4), 1.5g of PAN was replaced with 2g of polyvinyl alcohol (PVA, number average molecular weight: 20000, the same applies hereinafter), and DMF was replaced with distilled water to obtain a solution having a mass content of 9% by weight, yielding a flexible electrode material S4. The thickness of the prepared flexible electrode material S4 was 0.5 mm.
SEM analysis is carried out on the flexible electrode material S4, and the result of the SEM analysis shows that LiCoO2The particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S4, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 5
Lithium-containing metal oxide LiMn2O4and preparing the flexible electrode material.
(1) LiCH with the molar ratio of 1:23COO·2H2O and MnO2putting the mixture into a ball milling tank, and then adding 20mL of acetone for wet ball milling; the mixture obtained by ball milling is dried in an oven under vacuum at 90 ℃ for 12h, then calcined in a muffle furnace under air atmosphere at 700 ℃ for 10h, and then ground to obtain LiMn2O4powder (particle size about 1 μm);
(2) Weighing 0.5g of PAN, dissolving in DMF solution, and stirring to form a solution with the mass content of 10 wt%;
(3) Weighing 0.8g of LiMn obtained in the step (1)2O4Adding powder into the solution, uniformly stirring, then sequentially performing ultrasonic dispersion (50kHz, 2 hours) and magnetic stirring (400rpm and 10 hours) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable syringe, putting the syringe into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive the nano-fibers obtained by spinning, wherein the electrostatic spinning conditions comprise that: the advancing speed is 0.05mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 20cm, the spinning voltage is 16kV, the obtained spinning material is taken off from the aluminum foil, the pretreatment is carried out for 3h at 280 ℃ in a muffle furnace, and then the heat treatment is carried out for 6h at 600 ℃ in the argon atmosphere, thus obtaining the flexible electrode material S5. The thickness of the prepared flexible electrode material S5 was 1.5 mm.
SEM analysis is carried out on the flexible electrode material S5, and the result of the SEM analysis shows that LiMn2O4the particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S5, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 6
Polyanionic silicates Li2FeSiO4And preparing the flexible electrode material.
(1) 3.0606g of CH3COOLi·2H2O and 6.06g Fe (NO)3)3·9H2dissolving O in 30mL of deionized water in sequence; 3.1250g of Tetraethylorthosilicate (TEOS) were dissolved in 20mL of ethanol; then mixing the two; then adding 3.1521g of citric acid, stirring in water bath for 10h at 70 ℃ to obtain sol, drying in a drying oven at 80 ℃ for 24h in vacuum to obtain dry glue, grinding the obtained dry glue uniformly, and calcining in a 650 ℃ tube furnace for 10h to obtain Li2FeSiO4solid powder (particle size about 3 μm);
(2) Weighing 1g of PAN powder, dissolving the PAN powder in a DMF solution, and stirring to form a solution with the mass content of 8.3 wt%;
(3) Weighing 1.5g of Li obtained in step (1)2FeSiO4Adding solid powder into the solution, uniformly stirring, then sequentially performing ultrasonic dispersion (100kHz, 2 hours) and magnetic stirring (600rpm, 10 hours) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable syringe, putting the syringe into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive the nano-fibers obtained by spinning, wherein the electrostatic spinning conditions comprise that: the advancing speed is 0.1mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 15cm, the spinning voltage is 22kV, the obtained spinning material is taken off from the aluminum foil, the pretreatment is carried out for 2h at 280 ℃ in a tubular furnace, and then the heat treatment is carried out for 8h at 650 ℃ to obtain the flexible electrode material S6. The thickness of the prepared flexible electrode material S6 was 2 mm.
SEM analysis is carried out on the flexible electrode material S6, and the SEM analysis result shows that Li2FeSiO4The particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S6, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 7
polyanionic silicates Li2MnSiO4And preparing the flexible electrode material.
(1) 3.0606g of CH3COOLi·2H2o and 3.6764g Mn (CH)3COO)2·4H2Dissolving O in 30mL of deionized water in sequence; 3.1250g of tetraethyl orthosilicate(TEOS) dissolved in 20mL ethanol; then mixing the two; then adding 3.1521g of citric acid, stirring in water bath at 70 ℃ for 10h to obtain sol, drying in a drying oven at 80 ℃ for 24h in vacuum to obtain dry glue, grinding the obtained dry glue uniformly, and calcining in a 700 ℃ tube furnace for 6h to obtain Li2MnSiO4Solid powder (particle size about 1 μm);
(2) Weighing 1g of PAN powder, dissolving the PAN powder in a DMF solution, and stirring to form a solution with the mass content of 8.3 wt%;
(3) weighing 1g of Li obtained in step (1)2MnSiO4Adding solid powder into the solution, uniformly stirring, then sequentially performing ultrasonic dispersion (100kHz, 2 hours) and magnetic stirring (600rpm, 10 hours) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable syringe, putting the syringe into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive the nano-fibers obtained by spinning, wherein the electrostatic spinning conditions comprise that: the advancing speed is 0.1mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 15cm, the spinning voltage is 22kV, the obtained spinning material is taken off from the aluminum foil, the pretreatment is carried out for 2h at 280 ℃ in a tubular furnace, and then the heat treatment is carried out for 8h at 700 ℃ to obtain the flexible electrode material S7. The thickness of the prepared flexible electrode material S7 was 2 mm.
SEM analysis is carried out on the flexible electrode material S7, and the SEM analysis result shows that Li2MnSiO4The particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S7, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 8
Lithium-rich manganese-based material Li1.2Ni0.2Mn0.6O2And (4) preparing a flexible electrode.
(1) Lithium-rich manganese-based material Li1.2Ni0.2Mn0.6O2Prepared by a coprecipitation method. Mixing a mixture of 3: 1, respectively dissolving manganese nitrate and nickel nitrate in deionized water, and then mixing to obtain a mixed solution A with the molar concentration of 0.05M; compounding mole(NH) at a concentration of 0.0525M4)2C2O4Solution B; uniformly mixing the mixed solution A and the solution B under magnetic stirring by adopting a peristaltic pump, and adding ammonia water to adjust the pH value of the reaction tank to be about 7.0; washing, filtering and drying the obtained precipitate, and mixing with excess LiNO3powder (LiNO, calculated as metal element)3The molar ratio of the mixed powder to the manganese nitrate is 2.1), pre-burning the uniformly mixed powder in a muffle furnace at 500 ℃ for 4h, and then calcining the powder at 900 ℃ for 12h to obtain the lithium-rich manganese-based material powder Li1.2Ni0.2Mn0.6O2(particle size about 200 nm);
(2) Weighing 1g of PAN powder, dissolving the PAN powder in dimethylacetamide, and stirring to form a solution with the mass content of 15 wt%;
(3) Weighing 1.5g of Li obtained in step (1)1.2Ni0.2Mn0.6O2adding powder into the solution, uniformly stirring, then sequentially performing ultrasonic dispersion (300kHz, 3h) and magnetic stirring (500rpm and 10h) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable syringe, putting the syringe into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive the nano-fibers obtained by spinning, wherein the electrostatic spinning conditions comprise that: the advancing speed is 0.1mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 15cm, the spinning voltage is 22kV, the obtained spinning material is taken off from the aluminum foil, the pretreatment is carried out for 2h at 280 ℃ in a muffle furnace, and then the heat treatment is carried out for 8h at 900 ℃ in the argon atmosphere, thus obtaining the flexible electrode material S8. The thickness of the prepared flexible electrode material S8 was 2 mm.
SEM analysis is carried out on the flexible electrode material S8, and the SEM analysis result shows that Li1.2Ni0.2Mn0.6O2The particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S8, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 9
ternary material LiNi0.8Co0.1Mn0.1O2And (4) preparing a flexible electrode.
(1) Ternary material LiNi0.8Co0.1Mn0.1O2prepared by a coprecipitation method. Respectively dissolving nickel sulfate, cobalt sulfate and manganese sulfate with a molar ratio of 8:1:1 in deionized water, and preparing a mixed solution A with a molar concentration of 2.0 mol/L; preparing NaOH solution B with the molar concentration of 2.0 mol/L; in the introduction of N2Under the premise of protective gas, a peristaltic pump is adopted to uniformly mix the mixed solution A and the solution B under magnetic stirring, and ammonia water is added to adjust the pH value of the reaction tank to be about 7.0; washing, filtering and drying the obtained precipitate, and mixing with excess LiNO3Powder (LiNO, calculated as metal element)3The molar ratio of the mixed powder to the manganese nitrate is 10.5), and the uniformly mixed powder is calcined in a muffle furnace at 900 ℃ for 12 hours to obtain ternary material powder LiNi0.8Co0.1Mn0.1O2(particle size about 5 μm);
(2) Weighing 1g of PAN powder, dissolving the PAN powder in DMF, and stirring to form a solution with the mass content of 7.1 wt%;
(3) Weighing 0.5g of LiNi obtained in the step (1)0.8Co0.1Mn0.1O2Adding the powder into the solution, uniformly stirring, then sequentially performing ultrasonic dispersion (40kHz, 2h) and magnetic stirring (500rpm, 10h) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable syringe, putting the syringe into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive the nano-fibers obtained by spinning, wherein the electrostatic spinning conditions comprise that: the advancing speed is 0.05mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 18cm, the spinning voltage is 18kV, the obtained spinning material is taken off from the aluminum foil, the pretreatment is carried out for 2h at 280 ℃ in a muffle furnace, and then the heat treatment is carried out for 15h at 900 ℃ in the argon atmosphere, thus obtaining the flexible electrode material S9. The thickness of the prepared flexible electrode material S9 was 0.5 mm.
SEM analysis is carried out on the flexible electrode material S9, and the result of the SEM analysis shows that LiNi0.8Co0.1Mn0.1O2the particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S9, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 10
Lithium-containing metal oxide material Li4Ti5O12And (4) preparing the flexible negative electrode.
(1) Synthesis of Li by hydrothermal method4Ti5O12. 0.1g of TiO2The microspheres were dispersed in 32mL of deionized water and sonicated for 20min, followed by 8mL of an aqueous LiOH solution (0.4mol/L) added dropwise with stirring. After maintaining the sonication and stirring for 10min, the resulting mixed solution was transferred to a 50mL reaction kettle and heated at 150 ℃ for 24h, and then cooled to room temperature. Washing the obtained precipitate with deionized water and ethanol for 3 times, vacuum drying at 60 deg.C for 12 hr, grinding the obtained powder, and heating at 600 deg.C for 2 hr in muffle furnace under air atmosphere to obtain Li4Ti5O12Powder (particle size about 500 nm);
(2) Weighing 1.5g of PAN powder, dissolving in DMF solution, and stirring to form a solution with the mass content of 10 wt%;
(3) Weighing 1g of Li obtained in step (1)4Ti5O12Adding powder into the solution, uniformly stirring, then sequentially performing ultrasonic dispersion (100kHz, 3h) and magnetic stirring (400rpm and 10h) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable syringe, putting the syringe into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive the nano-fibers obtained by spinning, wherein the electrostatic spinning conditions comprise that: the advancing speed is 0.1mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 20cm, the spinning voltage is 19kV, the obtained spinning material is removed from the aluminum foil, the pretreatment is carried out for 2h at 280 ℃ in a muffle furnace, and then the heat treatment is carried out for 2h at 450 ℃ in a tube furnace under the argon atmosphere, thus obtaining the flexible electrode material S10. The thickness of the prepared flexible electrode material S10 was 1 mm.
SEM analysis is carried out on the flexible electrode material S10, and the SEM analysis result shows that Li4Ti5O12The particles are distributed in a plurality ofBetween the carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S10, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
Example 11
And preparing the silicon cathode flexible electrode.
(1) The molar mass ratio of the metal magnesium powder to the silicon dioxide is 2: 1, grinding uniformly, then placing the mixture into a reaction kettle, heating the mixture in an electric heating furnace at 650 ℃ for 12h, placing the mixture into 1mol/L diluted hydrochloric acid to soak for 30min after a sample is naturally cooled, then cleaning the extract with deionized water and ethanol (three times each), soaking the extract in a hydrofluoric acid aqueous solution (with the concentration of 50 wt%) for 30min after vacuum drying (70 ℃ and 12h), cleaning the extract with the deionized water and the ethanol for 3 times respectively, and then carrying out vacuum drying (70 ℃ and 12h) to obtain nano silicon particles (the particle size is about 150 nm);
(2) Weighing 1g of PAN powder, dissolving the PAN powder in dimethyl sulfoxide (DMSO), and stirring to form a solution with the mass content of 6.67 wt%;
(3) weighing 1g of nano silicon powder obtained in the step (1), adding the nano silicon powder into the solution, uniformly stirring, sequentially performing ultrasonic dispersion (100kHz, 3h) and magnetic stirring (500rpm, 10h) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable injector, putting the injector into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive nano fibers obtained by spinning, wherein the electrostatic spinning condition comprises that: the advancing speed is 0.1mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 20cm, the spinning voltage is 19kV, the obtained spinning material is removed from the aluminum foil, the pretreatment is carried out for 2h at 280 ℃ in a tubular furnace under the argon atmosphere, and then the heat treatment is carried out for 4h at 600 ℃ in the tubular furnace under the argon atmosphere, so that the flexible electrode material S11 is obtained. The thickness of the prepared flexible electrode material S11 was 1 mm.
SEM analysis of the flexible electrode material S11 showed that the silicon particles were distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S11, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
example 12
transition metal oxide Fe3O4And preparing the flexible electrode material.
(1) 1.6g of iron chloride hexahydrate (FeCl)3·6H2O) and 0.6g of sodium acetate (CH)3COONa) is added into a mixed solvent of 60mL of ethylene glycol and 12mL of ethylenediamine, 1.6g of glucose is added into the mixed solution, the mixed solution is transferred into a 100mL reaction kettle after being uniformly stirred, the mixed solution is reacted for 6h in a 180 ℃ oven, the obtained precipitate is washed for 3 times by deionized water and ethanol respectively, the precipitate is dried for 10h in a 70 ℃ oven in vacuum, ground and calcined for 2h at 400 ℃ in a tubular furnace in argon atmosphere to obtain Fe3O4Powder (particle size about 150 nm);
(2) Weighing 2g of polyvinyl alcohol (PVA) and dissolving in distilled water to obtain a solution with the mass content of 9 weight percent;
(3) 0.6g of Fe obtained in step (1) was weighed3O4Adding powder into the solution, uniformly stirring, then sequentially performing ultrasonic dispersion (100kHz, 3h) and magnetic stirring (500rpm, 10h) to obtain a spinning solution, filling the obtained spinning solution into a 10ml disposable syringe, putting the syringe into an electrostatic spinning instrument for electrostatic spinning, winding a circle of aluminum foil on a receiving roller to receive the nano-fibers obtained by spinning, wherein the electrostatic spinning conditions comprise that: the advancing speed is 0.08mm/min, the distance between a filament outlet (needle head) and a receiver (receiving roller) is 18cm, the spinning voltage is 19kV, the obtained spinning material is removed from the aluminum foil, the pretreatment is carried out for 2h at 280 ℃ in a tubular furnace under the argon atmosphere, and then the heat treatment is carried out for 4h at 600 ℃ in the tubular furnace under the argon atmosphere, so that the flexible electrode material S12 is obtained. The thickness of the prepared flexible electrode material S12 was 1 mm.
SEM analysis is carried out on the flexible electrode material S12, and the SEM result shows that Fe3O4The particles are distributed among the plurality of carbon nanofibers.
The diameter of the carbon nanofibers of the flexible electrode material S12, the average particle diameter of the host material particles, and the contents of the carbon nanofibers and the host material particles were analyzed, and the results are listed in table 1.
TABLE 1
Test example 1
Electrochemical performance tests were performed on the flexible battery materials obtained in examples 1 to 12 and comparative example 1. Specifically, the method comprises the following steps:
the flexible battery materials obtained in examples 1-12 and comparative example 1 were assembled into a lithium ion battery, a metal lithium plate was used as a counter electrode, a polypropylene porous membrane Celgard2400 was used as a separator, and 1mol/L of NaClO was used4the electrolyte solution (EC: EMC: DMC volume ratio is 1: 1: 1) is prepared by assembling a button cell (CR2025) in an argon glove box, standing for 24h, and performing charge and discharge test on a LAND CT2001A tester. The results are shown in Table 2.
TABLE 2
As can be seen from table 2, lithium ions assembled using the flexible electrode materials prepared in examples 1 to 12 can achieve reversible charge and discharge with high specific capacity, and have good cycling stability. In addition, the flexible electrode material provided by the invention does not need a current collector and a binder, does not need a conductive additive, and can be directly used for assembling a lithium ion battery. As can be seen from comparison of the results of example 1 and comparative example 1, the particle size of the flexible electrode material provided by the present invention is not limited by the carbon nanofibers, and the flexible electrode material can exhibit more excellent electrochemical cycling stability.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (21)
1. A lithium-ion battery comprising a flexible electrode material, the electrode material comprising: a carbon nanofiber network skeleton composed of a plurality of carbon nanofibers, and host material particles distributed among the plurality of carbon nanofibers; the flexible electrode material does not need a current collector, a binder and a conductive additive, and is directly used for assembling the lithium ion battery; the host material particles contain at least one of polyanionic phosphate, silicate, lithium-rich material, ternary material, transition metal oxide and lithium-containing metal oxide;
The thickness of the flexible electrode material of the lithium ion battery is 0.01-5 mm; the polyanionic phosphate is selected from LiFe1- yMyPO4And/or Li3V2-xMx(PO4)3M is at least one of Mg, Ni and Ti, x is more than or equal to 0 and less than or equal to 2, and y is more than or equal to 0 and less than or equal to 1;
The silicate is Li2RSiO4r is Fe and/or Mn;
The lithium-rich material is Li1.2Ni0.2Mn0.6O2；
The ternary material is LiNiaCobMncO2，0＜a＜1，0＜b＜1，0 < c < 1, and a + b + c = 1;
The transition metal oxide is Fe3O4And/or Co3O4；
The lithium-containing metal oxide is LiCoO2And/or LiMn2O4；
The average particle diameter of the main material particles is 1-5 μm;
The diameter of the carbon nanofiber is 100nm-500 nm;
the content of the main body material particles is 40-70 wt%, and the content of the carbon nano-fibers is 30-60 wt%;
The preparation method of the flexible electrode material comprises the following steps:
(1) dissolving a carbon-containing polymer in a solvent to obtain a solution;
(2) mixing the main body material and/or the precursor of the main body material with the solution to obtain spinning solution, and then performing electrostatic spinning to obtain a spinning substance;
(3) Sequentially carrying out pretreatment and heat treatment on the spinning substance to obtain a flexible electrode material of the lithium ion battery;
The precursor of the host material does not refer to a raw material for synthesizing the host material, but is a substance which has generated a certain interaction with each other and can be converted into the host material under the heat treatment condition in the step (3).
2. The lithium ion battery of claim 1, wherein the ternary material is LiNi0.8Co0.1Mn0.1O2、LiNi0.6Co0.2Mn0.2O2、LiNi0.4Co0.3Mn0.3O2、LiNi0.5Co0.3Mn0.2O2And LiNi1/3Co1/3Mn1/3O2At least one of (1).
3. The lithium ion battery of claim 1, wherein the host material particles comprise LiFePO4、Li3V2(PO4)3、LiCoO2、LiMn2O4、Li2FeSiO4、Li2MnSiO4、Li1.2Ni0.2Mn0.6O2、LiNi0.8Co0.1Mn0.1O2And Fe3O4At least one of (1).
4. A method of making a lithium ion battery according to claim 1, said lithium ion battery comprising a flexible electrode material, said method comprising:
(1) Dissolving a carbon-containing polymer in a solvent to obtain a solution;
(2) mixing a main body material and/or a precursor of the main body material with the solution to obtain a spinning solution, and then performing electrostatic spinning to obtain a spinning substance, wherein the particle size of the main body material is 1-5 mu m, and the particle size of the precursor of the main body material is 2-5 mu m;
(3) Sequentially carrying out pretreatment and heat treatment on the spinning substance to obtain a flexible electrode material of the lithium ion battery;
The ratio of the mass of the host material and/or precursor of the host material to the mass of the solution in terms of carbon-containing polymer is (0.3-1.5): 1.
5. The method according to claim 4, wherein the carbon-containing polymer is contained in an amount of 5 to 20 wt% based on the total weight of the solution.
6. The method according to claim 5, wherein the carbon-containing polymer is contained in an amount of 5 to 15 wt% based on the total weight of the solution.
7. The method according to claim 5, wherein the carbon-containing polymer is contained in an amount of 6.5 to 15 wt% based on the total weight of the solution.
8. The production method according to claim 4, wherein the carbon-containing polymer is selected from at least one of polyethylene oxide, polyvinylidene fluoride, polymethacrylate, polyethylene oxide, polyvinylpyrrolidone, polyvinylcarbazole, polybenzimidazole, polyethylene terephthalate, polymethyl methacrylate, polystyrene, polyurethane, polyvinyl alcohol, polylactic acid, polyacrylonitrile, and polyvinyl chloride.
9. The production method according to claim 8, wherein the carbon-containing polymer is at least one of polyacrylonitrile, polyethylene oxide, polyvinylpyrrolidone, and polyvinyl alcohol.
10. The production method according to claim 4, wherein the solvent is selected from at least one of dimethylformamide, dimethylacetamide, dimethylsulfoxide, ethylene carbonate, and water.
11. The method of claim 4, wherein the ternary material is LiNi0.8Co0.1Mn0.1O2、LiNi0.6Co0.2Mn0.2O2、LiNi0.4Co0.3Mn0.3O2、LiNi0.5Co0.3Mn0.2O2And LiNi1/3Co1/3Mn1/3O2At least one of (1).
12. The method according to claim 4, wherein the host material contains LiFePO4、Li3V2(PO4)3、LiCoO2、LiMn2O4、Li2FeSiO4、Li2MnSiO4、Li1.2Ni0.2Mn0.6O2、LiNi0.8Co0.1Mn0.1O2And Fe3O4At least one of (1).
13. The production method according to any one of claims 4 to 12, wherein, in the step (2), the mixing process includes: and (3) contacting the main body material and/or the precursor of the main body material with the solution, and then sequentially carrying out ultrasonic dispersion and magnetic stirring.
14. The method of claim 13, wherein the ultrasonic dispersion has a frequency of 40kHz to 100kHz for 0.5 to 6 hours.
15. The method of claim 13, wherein the magnetic stirring is performed at a speed of 150rpm to 1000rpm for 1 to 20 hours.
16. The production method according to any one of claims 4 to 12,
The electrostatic spinning conditions include: the voltage is 10kV-30 kV; the distance between the filament outlet and the receiver is 10cm-25 cm; the advancing speed is 0.01mm/min-0.5 mm/min.
17. the production method according to claim 16, wherein,
The electrostatic spinning conditions include: the voltage is 15kV-22 kV; the distance between the filament outlet and the receiver is 15cm-20 cm; the advancing speed is 0.08mm/min-0.2 mm/min.
18. the production method according to any one of claims 4 to 12,
the pretreatment conditions include: the temperature is 100-500 deg.C, and the time is 30-300 min.
19. The production method according to claim 18,
The pretreatment conditions include: the temperature is 250-350 deg.C, and the time is 120-300 min.
20. The production method according to any one of claims 4 to 12,
The conditions of the heat treatment include: under inert atmosphere, the temperature is 300-1600 ℃, and the time is 1-12 h.
21. The production method according to claim 20, wherein the conditions of the heat treatment include: the temperature is 450-900 ℃ and the time is 2-12 h.
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| CN112226913A (en) * | 2020-09-28 | 2021-01-15 | 陈燕 | Preparation method of composite film material applied to lithium battery diaphragm |
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| CN113224293B (en) * | 2021-04-02 | 2022-03-29 | 湖北工程学院 | Preparation method and application of titanium carbide/carbon nano-film material |
| CN113097466B (en) * | 2021-04-02 | 2023-09-01 | 山西君东新材料股份有限公司 | Negative electrode material MoS of lithium ion battery 2 Preparation method of @ CFs |
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