CN116130758A - Electrolyte for compact polymer-based solid-state lithium battery - Google Patents

Electrolyte for compact polymer-based solid-state lithium battery Download PDF

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CN116130758A
CN116130758A CN202310402355.2A CN202310402355A CN116130758A CN 116130758 A CN116130758 A CN 116130758A CN 202310402355 A CN202310402355 A CN 202310402355A CN 116130758 A CN116130758 A CN 116130758A
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electrolyte
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lithium battery
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CN116130758B (en
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陆盈盈
武倩
程豪
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Zhejiang University ZJU
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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Abstract

The invention discloses an electrolyte for a compact polymer-based solid-state lithium battery. The electrolyte comprises lithium salt, an organic solvent, polyvinylidene fluoride polymer and molybdenum diselenide. The PVDF-based solid electrolyte prepared by the invention takes molybdenum diselenide as a filler, the densification degree is obviously improved, and the content of beta-phase PVDF, the dielectric constant of the electrolyte, the ion conductivity, the ion migration activation energy and the oxidation resistant window of the electrolyte are all improved.

Description

Electrolyte for compact polymer-based solid-state lithium battery
Technical Field
The invention belongs to the technical field of lithium batteries, and particularly relates to an electrolyte for a compact polymer-based solid-state lithium battery.
Background
The lithium ion battery has the advantages of high energy density, long cycle life and the like, and has been widely applied to the fields of portable electronic equipment, medical electronic equipment, new energy automobiles and the like. At present, the traditional lithium ion battery material system basically reaches the energy density limit, and the increasingly pursuit of the aspects of light weight, high energy and the like of the energy storage device is difficult to meet. The use of high energy density positive and negative electrode materials is a viable route for constructing high energy density lithium ion batteries. Wherein, the high nickel ternary material LiNi 8 Co 1 Mn 1 O 2 (NCM 811) and lithium goldThe genus respectively has more than 200 mAh g -1 And 3860 mAh g -1 Is considered as one of the positive electrode material and the negative electrode material that is most promising for achieving high energy density. However, they have disadvantages of serious interfacial side reaction, rapid capacity decay, short cycle life, etc. which severely limit their practical applications in liquid lithium ion batteries prepared with organic liquid electrolytes. In contrast, the solid electrolyte has the advantages of high mechanical strength, good electrochemical stability and the like, and the solid electrolyte is used for replacing the organic liquid electrolyte, so that the safety problem of the battery is hopefully fundamentally solved, and the energy density of the battery is improved.
Among many solid electrolyte systems, polymer electrolytes have the advantages of good ductility, good interface contact, easy preparation and the like, and are one of the most studied solid electrolytes. Among them, polyvinylidene fluoride (PVDF) -based polymer solid electrolyte exhibits relatively high room temperature ionic conductivity due to the presence of a small amount of N, N-Dimethylformamide (DMF) solvent residue (10 -4 S cm -1 ) The conditions for the operation of the solid-state battery at room temperature can be satisfied. However, PVDF electrolytes face a number of problems. First, phase separation of the solvent and the polymer during the preparation process causes the electrolyte to exhibit a porous structure, so that lithium ion transport and lithium deposition are not uniform, and a battery short circuit phenomenon is very easily caused. Second, room temperature ionic conductivity needs to be further improved to meet practical requirements. Thirdly, the Highest Occupied Molecular Orbital (HOMO) energy level of DMF is higher, the oxidation resistance is poor, and the DMF is continuously decomposed under high voltage; the spontaneous interfacial side reaction with lithium metal, especially serious side reaction under high current density, causes the electrochemical stability of PVDF-based electrolyte to be improved. Based on the above problems, improvement in long life, high voltage, high rate operation, etc. is needed for a full battery prepared by matching a PVDF-based solid electrolyte with NCM811 positive electrode and lithium metal negative electrode.
Currently, strategies for improving ionic conductivity and electrochemical stability of PVDF-based solid state electrolytes can be broadly divided into two categories: (1) introducing a filler to construct a composite solid electrolyte; (2) modification of the molecular structure of the polymer. In the above method, the filler is introduced withThe following advantages are achieved: (1) The filler is introduced and uniformly distributed in the pores of the electrolyte body, and has certain interaction with DMF solvent, so that the distribution State of the solvent can be changed, and the electrochemical stability of the electrolyte is improved [ Ke Yang, et al, "' Stable Interface Chemistry and Multiple Ion Transport of Composite Electrolyte Contribute to Ultra-long Cycling Solid-State LiNi ] 0.8 Co 0.1 Mn 0.1 O 2 /Lithium Metal Batteries”, Angewandte Chemie International Edition (2021).]The method comprises the steps of carrying out a first treatment on the surface of the (2) By utilizing the chemical reaction of the filler and lithium metal, DMF decomposition is inhibited and a solid electrolyte interface film (SEI) is constructed in situ, so that the interface side reaction [ Likun Chen et al, "In situ construction of Li" is reduced 3 N-enriched interface enabling ultra-stable solid-state LiNi 0.8 Co 0.1 Mn 0.1 O 2 /lithium metal batteries”, Nano Energy (2022).]. Therefore, the electrochemical stability and the interface stability of the PVDF-based solid electrolyte can be improved by introducing the filler, and the property of the filler plays a key role. However, the interaction forces of the fillers and the polymer bodies reported so far are generally weak, so that the prepared composite solid electrolyte is still not compact. In addition, although the active filler itself has a certain ionic conductivity, which can improve the ionic conductivity of the electrolyte, the solvation structure of PVDF electrolyte is a core factor, and a method of improving the ionic conductivity by controlling the solvation structure has been neglected.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a PVDF-based composite solid electrolyte taking molybdenum diselenide as a multifunctional filler, and a preparation method and application thereof.
An electrolyte for a compact polymer-based solid state lithium battery comprising a lithium salt, a polyvinylidene fluoride polymer, and an organic solvent sufficient to dissolve the polyvinylidene fluoride polymer, the electrolyte further comprising molybdenum diselenide,
the mass ratio of the polyvinylidene fluoride polymer to the lithium salt is 1-1.5:1;
the mass ratio of the molybdenum diselenide to the polyvinylidene fluoride polymer is 0.10-0.20:1.
In the present application, the amount of the organic solvent is not particularly limited, and the amount of the organic solvent is only required to sufficiently dissolve the polyvinylidene fluoride polymer. For example, the mass to volume ratio of polyvinylidene fluoride polymer to organic solvent is 405mg to 5ml.
Preferably, the lithium salt is at least one of lithium bis (fluorosulfonyl) imide, lithium bis (trifluoromethylsulfonyl) imide and lithium perchlorate. The organic solvent is at least one of N, N dimethylformamide, dimethylacetamide, dimethyl sulfoxide, triethyl phosphate and tetrahydrofuran. The molecular weight of the polyvinylidene fluoride polymer is 30-90 ten thousand.
The invention also provides a preparation method of the electrolyte for the compact polymer-based solid-state lithium battery, which comprises the following steps:
(1) Providing a lithium salt, an organic solvent, a polyvinylidene fluoride polymer, and molybdenum diselenide;
(2) Dissolving lithium salt, polyvinylidene fluoride polymer and molybdenum diselenide in an organic solvent, and fully complexing to obtain slurry;
(3) And (3) forming a film from the slurry obtained in the step (2) to obtain the electrolyte for the compact polymer-based solid-state lithium battery.
Preferably, in the step (2), the heating temperature is 40-60 ℃ and the heating time is 6-8 hours during the complexing.
Preferably, in the film forming in the step (3), the slurry is uniformly cast on a glass substrate, and then is dried by blowing to obtain a self-supporting film, namely the electrolyte for the compact polymer-based solid-state lithium battery. More preferably, the temperature at the time of air-drying is 55-80 ℃ and the drying time is 12-18 hours.
In the film forming process of the step (3), most of the organic solvent can be removed during drying, but the organic solvent cannot be completely removed, and part of the organic solvent which is strongly combined with the lithium salt can remain. The invention also provides application of the electrolyte for the compact polymer-based solid-state lithium battery in preparation of the lithium battery.
The invention has the beneficial effects that:
tests show that the PVDF-based solid electrolyte prepared by the invention is diselenizedMolybdenum is used as filler, the densification degree of the solid electrolyte is obviously improved, the content of beta-phase PVDF is improved from 40% to 64%, the dielectric constant of the electrolyte is improved from 9.8 to 21.1, and the ionic conductivity of the electrolyte is improved from 2.1 multiplied by 10 -4 S cm -1 Is increased to 6.4X10 -4 S cm -1 Ion migration activation energy is reduced from 0.26 to eV to 0.07 to eV, and oxidation resistance window is increased from 4.3 to V to 4.7 to V.
Meanwhile, molybdenum diselenide can react with lithium metal in situ, lithium selenide is generated in a solid electrolyte interface film (SEI), the lithium selenide has strong ion migration capability, interface ion migration dynamics can be enhanced, DMF (dimethyl formamide) decomposition at an interface is inhibited, electrochemical stability of electrolyte and lithium metal compatibility are enhanced, and stability of the full battery under high multiplying power is achieved.
The solid electrolyte prepared by the method has low cost, simple process, strong adaptability and universality, and can realize long-term stable circulation of a full battery prepared by taking NCM811 as a positive electrode and lithium metal as a negative electrode at high multiplying power of 3C, high charging cut-off voltage of 4.5V and even wide temperature range of-20-45 ℃.
Drawings
Fig. 1 is a scanning electron micrograph of the electrolyte prepared in example 1.
Fig. 2 is a scanning electron micrograph (fig. 2 (a)) of the electrolyte prepared in example 2 and a partial enlarged scanning electron micrograph (fig. 2 (b)).
Fig. 3 is a fourier transform infrared spectrum of the electrolyte prepared in example 1, example 2, example 3, example 4.
Fig. 4 is a graph showing the dielectric constant test curves of the electrolytes prepared in example 1 (fig. 4 (a)) and example 2 (fig. 4 (b)) at different temperatures.
Fig. 5 is an electrochemical window test curve of the electrolyte prepared in example 1 and example 2.
Fig. 6 is a raman spectrum test curve of the electrolyte prepared in example 1 (fig. 6 (a)), example 2 (fig. 6 (b)).
Fig. 7 shows ion conductivity test results of the electrolytes prepared in example 1 and example 2 at different temperatures.
Fig. 8 is a freeze transmission electron micrograph of lithium metal after cycling of the electrolyte prepared in example 2, wherein (a) in fig. 8 is a high resolution freeze transmission electron micrograph and (b) in fig. 8 is a fast fourier transform of region (a) in fig. 8.
Fig. 9 is a graph showing critical current density test of the assembled button cell prepared in example 1 and example 2.
Fig. 10 is a graph showing the results of the rate performance test of the assembled coin cell batteries of the electrolytes prepared in examples 1, 2, 3 and 4 at 0.1C, 0.2C, 0.5C, 1C, 2C and 5C rates.
Fig. 11 is a graph showing the results of the cycle performance test of the electrolyte prepared in example 1 and example 2 assembled into a coin cell at 2C rate.
Fig. 12 is a graph showing the results of the cycle performance test of the electrolyte prepared in example 1 and example 2 assembled into a coin cell at 3C rate.
Fig. 13 is a graph showing the results of the cycle performance test of the electrolyte prepared in example 1 and example 2 assembled into a coin cell at 2C rate.
Fig. 14 is a graph showing the results of the cycle performance test of the electrolyte prepared in example 1 (fig. 14 (b)) and example 2 (fig. 14 (a)) assembled into a button cell at 2C rate.
Fig. 15 is a graph showing the results of the cycle performance test of the electrolyte prepared in example 2 assembled into a coin cell at 0.1C rate.
Detailed Description
Example 1
270 mg of LiFSI (lithium bis-fluorosulfonyl imide) is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF (N, N-dimethylformamide) and 405mg of PVDF (polyvinylidene fluoride, molecular weight 30 ten thousand) are added and stirred on a small stirrer, and heating and stirring are carried out at 40 ℃ for 8 and h until LiFSI and PVDF are completely dissolved to obtain uniform transparent slurry. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 2
270 mg of LiFSI was weighed under an argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (30 ten thousand molecular weight) and 60 mg of molybdenum diselenide nanosheets (manufacturer: shanghai Alasdine Biotechnology Co., ltd., product No. M196231-5g, CAS: 12058-18-3) were added and stirred on a small stirrer, and heated and stirred at 40℃for 8 h until LiFSI and PVDF were completely dissolved to obtain a uniform transparent slurry. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 3
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (molecular weight: 30 ten thousand) and 40 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, and uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 4
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (molecular weight: 30 ten thousand) and 80 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, and uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 5
Under argon atmosphere, 405mg LiFSI was weighed and placed in a stirring bottle, 5mL DMF, 405mg PVDF (molecular weight: 30 ten thousand) and 60 mg molybdenum diselenide nanosheets were added and stirred on a small stirrer, heated and stirred at 40℃for 8 h until LiFSI and PVDF were completely dissolved to obtain a uniform transparent slurry. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 6
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (molecular weight: 30 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, and uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 70 ℃ for 15 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 7
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (molecular weight: 30 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, and uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 80 ℃ for 12 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 8
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (molecular weight: 30 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, and heating and stirring are carried out at 60 ℃ for 6 h until LiFSI and PVDF are completely dissolved, so that uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 70 ℃ for 15 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 9
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (molecular weight 40 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, and uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 10
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (molecular weight 53.4 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, and uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 11
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMF, 405mg of PVDF (molecular weight of 90 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, and uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 12
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMAc (dimethylacetamide), 405mg of PVDF (molecular weight of 30 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, and the stirring is carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, so that uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 13
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of DMSO (dimethyl sulfoxide), 405mg of PVDF (molecular weight of 30 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, and heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, so that uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 14
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of TEP (triethyl phosphate), 405mg of PVDF (molecular weight of 30 ten thousand) and 60 mg of molybdenum diselenide nano-sheets are added and stirred on a small stirrer, and the stirring is carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, so that uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 15
270 mg of LiFSI is weighed under argon atmosphere and placed in a stirring bottle, 5mL of THF (tetrahydrofuran), 405mg of PVDF (molecular weight 30 ten thousand) and 60 mg of molybdenum diselenide nanosheets are added and stirred on a small stirrer, and heating and stirring are carried out at 40 ℃ for 8 h until LiFSI and PVDF are completely dissolved, so that uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 16
270 mg LiTFSI (lithium bistrifluoromethyl sulfoacid imide) is weighed under argon atmosphere and placed in a stirring bottle, 5mL DMF, 405mg PVDF (molecular weight 30 ten thousand) and 60 mg molybdenum diselenide nano-sheets are added and stirred on a small stirrer, and heating and stirring are carried out at 40 ℃ for 8 h until LiTFSI and PVDF are completely dissolved, so that uniform transparent slurry is obtained. Casting the slurry on a glass substrate, and drying in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Example 17
270 mg LiClO was weighed under an argon atmosphere 4 (lithium perchlorate) in a stirring flask, adding 5mL DMF, 405mg PVDF (molecular weight 30 ten thousand), 60 mg molybdenum diselenide nanosheets, stirring on a small stirrer, heating at 40deg.C for stirring 8 h, and stirring to LiClO 4 And PVDF is completely dissolved to obtain uniform transparent slurry. Casting the slurry to glassAnd (3) drying the substrate in a blast oven at 55 ℃ for 18 hours to obtain a white solid electrolyte membrane, blanking the white solid electrolyte membrane to a proper size, and drying and preserving the white solid electrolyte membrane in an inert atmosphere for use.
Detection example 1
The electrolytes prepared in examples 1 and 2 were each subjected to morphological analysis by scanning electron microscopy (SEM, HITACH S4800) with a set voltage of 5 kV. The results are shown in fig. 1 and 2, wherein the electrolyte before modification in fig. 1 is of a non-dense porous structure; in fig. 2 (a), it can be seen that the morphology of the modified electrolyte is changed obviously from a porous structure to a compact structure, and in fig. 2 (b) with larger magnification, the adsorption force of molybdenum diselenide and PVDF is shown to be stronger, which indicates that there is stronger interaction between the two. It is explained that the addition of molybdenum diselenide can obtain a dense solid electrolyte membrane.
Fig. 3 is a fourier transform infrared spectrum of the electrolyte prepared in example 1, example 2, example 3, and example 4, which shows that the proportion of beta-phase PVDF is 40%, 64%, 52%, 77%, respectively, and that the addition of molybdenum diselenide can induce phase transformation of PVDF, so that the proportion of high-polarity beta-phase PVDF is increased.
Fig. 4 is a dielectric constant test curve of the electrolyte prepared in example 1 and example 2. Fig. 4 (a) shows the dielectric constant test curves at different temperatures of the electrolyte prepared in example 1, and fig. 4 (b) shows the dielectric constant test curves at different temperatures of the electrolyte prepared in example 2. The figure illustrates that an increase in the proportion of high polarity beta-phase PVDF increases the dielectric constant of the electrolyte itself from 9.8 to 21.1.
Fig. 5 is an oxidation resistance window test curve of the electrolyte prepared in example 1 and example 2. The figure shows that the addition of molybdenum diselenide increases the oxidation resistance potential of the electrolyte from 4.3V to 4.7V, which is beneficial to inhibiting the oxidative decomposition of the electrolyte at high voltage.
Detection example 2
The electrolytes prepared in examples 1 and 2 were subjected to Raman analysis using a micro-laser confocal Raman spectrometer (Raman, MDTC-EQ-M15-01), respectively. As a result, as shown in fig. 6, the increase of dielectric constant of the electrolyte regulates the solvation structure to generate more free anions and contact ion pairs, and the number of ion aggregates is reduced, which is beneficial to improving the ion conductivity and reducing the ion migration activation energy. The figure illustrates that the addition of molybdenum diselenide allows for the modulation of solvation structures resulting in more free anions and contact ion pairs and a reduction in the number of ionic aggregates.
Fig. 7 shows ion conductivity test results of the electrolytes prepared in example 1 and example 2 at different temperatures. It can be seen that the addition of molybdenum diselenide leads to a room temperature ionic conductivity of from 2.1X10 -4 S cm -1 Is increased to 6.4X10 -4 S cm -1 The ion migration activation energy is reduced from 0.26 to eV to 0.07 to eV, and the ion migration capacity of the electrolyte is greatly improved.
Detection example 3
The solid electrolyte membrane prepared in example 2 was used as an electrolyte, lithium metal was used as a negative electrode, and LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811) A button cell was assembled for the positive electrode and cycled at 2C rate. Morphology and structural analysis of the cycled lithium metal surface was performed using a Cryo-transmission electron microscope (Cryo-TEM, FEI Talos-S). As shown in fig. 8, the in-situ reaction of molybdenum diselenide and lithium metal is shown to generate lithium diselenide, and the lithium diselenide is used as an ion conductor, so that the interfacial ion migration dynamics of the solid electrolyte can be remarkably enhanced, and the stability of the battery under high current density is maintained. FIG. 9 is a graph illustrating the critical current density test of assembled button cells prepared in example 1 and example 2, illustrating the addition of molybdenum diselenide to achieve a solid electrolyte critical current density of from 0.8 mA cm -2 Is increased to 2.3 mA cm -2 。
Detection example 4
1. And (5) preparing a pole piece.
The preparation of the conventional positive plate adopts a slurry coating method. The positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM 811) layered oxide (brand: canrd (Korea), cat# MA-EN-CA-0B 0207), conductive agent Super P (brand: canrd (Korea), cat# MA-EN-CO-010212, CAS:1333-86-4), and binder PVDF(manufacturer: arkema Kynar, model: HSV900, CAS: 24937-79-9) in a mass ratio of 80:10:10 by a high-speed vibration mixer, adding 2.70-2.75 mL of N-methyl-2-pyrrolidone (NMP) (brand: canrd (Kodado)), stirring for 8 hours until the slurry is completely mixed. The obtained slurry was coated on an aluminum foil having a thickness of 0.01 mm with a coater, and the electrode sheet was transferred to a forced air drying oven and dried at 70℃for 4 hours. Then, the electrode sheet was further vacuum-dried in a vacuum drying oven at 110℃for 12 hours to remove NMP and water. And finally, compacting the dried pole piece on an electric pair roller machine, and placing the compacted pole piece into a glove box for storage for later use. The active material load of the positive plate is 1-2 mg cm -2 。
The surface passivation of the lithium negative electrode slice is scraped by a plastic scraper until the surface shows metallic luster, and then the pole slice is cut.
2. And (5) assembling a battery.
The button cell is assembled by adopting a 2032 button cell shell. The button cell mainly comprises a positive electrode shell, a negative electrode shell, a positive electrode plate, a negative electrode plate, a solid electrolyte, a stainless steel spring piece and a stainless steel gasket. The electrolytes prepared in example 1, example 2, example 3, example 4 were cut into round pieces of 19 mm diameter by a manual microtome before assembly. The button cell was assembled in the order of positive electrode case/stainless steel gasket/positive electrode sheet/electrolyte/negative electrode sheet/stainless steel gasket/stainless steel spring sheet/negative electrode case. The entire assembly process was carried out in an argon glove box.
3. And (5) testing a battery.
The assembled coin cell was subjected to constant current cycling using a blue-electric (LANHE) battery test system (CT 2001A). The test conditions were: (1) the charge-discharge voltage range is 2.8-4.3/4.5V; the charge-discharge current (2) is: a. long cycle performance test: activating for 3 circles at 0.1C multiplying power, then continuing charging and discharging at 2C multiplying power, and testing the cycle performance; b. and (3) multiplying power performance test: after 3 circles of activation at 0.1C magnification, the magnification performance is tested at a larger magnification, such as 0.2C, 0.5C, 1C, 2C, 5C and the like; (3) test temperature: 25 ℃ (room temperature)/-20 ℃/45 ℃.
The solid electrolyte membranes prepared in examples 1, 2, 3 and 4 are used as electrolytes, the lithium metal is used as a negative electrode, the NCM811 is used as a positive electrode, and the battery rate performance tests at 0.1C, 0.2C, 0.5C, 1C, 2C and 5C rates are shown in FIG. 10, wherein the battery rate performance tests at 25 ℃ are shown in the voltage range of 2.8-4.3V, and the discharge capacity of the battery assembled by the electrolytes prepared in examples 2, 3 and 4 is higher than that of the battery assembled by the electrolytes prepared in example 1 under the same rate.
The solid electrolyte membranes prepared in example 1 and example 2 are respectively used as electrolytes, lithium metal is used as a negative electrode, NCM811 is used as a positive electrode, the cycle performance test is carried out under the 2C multiplying power, the voltage range is 2.8-4.3V, the battery cycle performance test under the 25 ℃ condition is shown in fig. 11, the cycle life of the electrolyte assembled battery prepared in example 2 is 2000 times, and the battery assembled in example 1 is short-circuited after 340 times of cycle; the coulombic efficiency of the electrolyte assembled battery prepared in example 1 is obviously higher than that of the electrolyte assembled battery prepared in example 2 in the electrochemical cycle performance test process, and the curve trend is consistent, which shows that the interface side reaction of the electrolyte after modification is reduced and the electrochemical stability is improved.
The solid electrolyte membranes prepared in example 1 and example 2 are respectively used as electrolytes, lithium metal is used as a negative electrode, NCM811 is used as a positive electrode, the cycle performance test is carried out under the 3C multiplying power, the voltage range is 2.8-4.3V, the high multiplying power cycle performance test of the battery under the 25 ℃ condition is shown in fig. 12, the cycle life of the battery assembled by the electrolyte prepared in example 2 is 2000 times, and the battery assembled by the electrolyte prepared in example 1 is short-circuited after 390 times of cycle.
The cycle performance test of the button cell assembled by using the solid electrolyte membranes prepared in example 1 and example 2 as electrolyte, lithium metal as anode and NCM811 as cathode under 2C ratio, the long cycle performance test of the cell at 45 ℃ under high temperature condition in 2.8-4.3V voltage interval is shown in FIG. 13, the cycle life of the cell assembled by using the electrolyte prepared in example 2 is 660 times, the capacity retention rate is 85.7%, and the capacity of the cell assembled by using the electrolyte prepared in example 1 is rapidly attenuated after 100 times of cycle. The composite electrolyte can obviously inhibit the decomposition of the solvent at high temperature and enhance the cycle stability of the battery at high temperature.
The cycle performance test of the button cell assembled by taking the solid electrolyte membranes prepared in the examples 1 and 2 as electrolytes, taking lithium metal as a negative electrode and taking NCM811 as a positive electrode under the 2C multiplying power is carried out, the high multiplying power cycle performance test of the cell under the condition of 25 ℃ is shown as a figure 14, the cycle life of the cell assembled by adopting the electrolyte prepared in the example 2 is 600 times, the capacity retention rate is 77.8%, and the cell assembled by adopting the electrolyte prepared in the example 1 is overcharged in the first circle. The composite electrolyte prepared in the example 2 has higher oxidation resistance.
The solid electrolyte membrane prepared in example 2 is used as an electrolyte, and the lithium metal is used as a negative electrode and the NCM811 is used as a positive electrode for assembling the button cell, the cycle performance test under the 0.1C multiplying power is carried out, the long cycle performance test of the cell under the high temperature condition of minus 20 ℃ in a voltage range of 2.8-4.3V is shown in figure 15, and the figure shows that the composite electrolyte has excellent ion conduction capability, so that the solid cell can stably circulate 150 times at low temperature.

Claims (9)

1. An electrolyte for a compact polymer-based solid state lithium battery comprising a lithium salt, a polyvinylidene fluoride polymer, and an organic solvent sufficient to dissolve the polyvinylidene fluoride polymer, characterized in that molybdenum diselenide is further included in the electrolyte,
the mass ratio of the polyvinylidene fluoride polymer to the lithium salt is 1-1.5:1;
the mass ratio of the molybdenum diselenide to the polyvinylidene fluoride polymer is 0.10-0.20:1.
2. The electrolyte for a dense polymer-based solid state lithium battery according to claim 1, wherein the lithium salt is at least one of lithium bis (fluorosulfonate) imide, lithium bis (trifluoromethylsulfonate) imide, and lithium perchlorate.
3. The electrolyte for a dense polymer-based solid lithium battery according to claim 1, wherein the organic solvent is at least one of N, N dimethylformamide, dimethylacetamide, dimethylsulfoxide, triethylphosphate, and tetrahydrofuran.
4. The electrolyte for a dense polymer-based solid state lithium battery according to claim 1, wherein the molecular weight of the polyvinylidene fluoride polymer is 30 to 90 ten thousand.
5. The method for preparing the electrolyte for the compact polymer-based solid-state lithium battery according to any one of claims 1 to 4, characterized by comprising the steps of:
(1) Providing a lithium salt, an organic solvent, a polyvinylidene fluoride polymer, and molybdenum diselenide;
(2) Dissolving lithium salt, polyvinylidene fluoride polymer and molybdenum diselenide in an organic solvent, and fully complexing to obtain slurry;
(3) And (3) forming a film from the slurry obtained in the step (2) to obtain the electrolyte for the compact polymer-based solid-state lithium battery.
6. The method according to claim 5, wherein the heating temperature in the step (2) is 40 to 60 ℃ and the heating time is 6 to 8 hours.
7. The method according to claim 5, wherein the electrolyte for the solid-state lithium battery is obtained by uniformly casting the slurry on a glass substrate and then air-drying the slurry to obtain a self-supporting film in the step (3) of film formation.
8. The method according to claim 7, wherein the temperature at the time of forced air drying is 55 to 80 ℃ and the drying time is 12 to 18 hours.
9. Use of the electrolyte for a compact polymer-based solid state lithium battery according to any one of claims 1 to 4 for the preparation of a lithium battery.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116742107A (en) * 2023-07-31 2023-09-12 武汉中科先进材料科技有限公司 Composite solid electrolyte membrane for lithium metal negative electrode and preparation method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030038610A1 (en) * 2001-03-30 2003-02-27 Munshi M. Zafar A. Structurally embedded intelligent power unit
US20080182176A1 (en) * 2007-01-25 2008-07-31 Doron Aurbach Rechargeable magnesium battery
WO2019010474A1 (en) * 2017-07-07 2019-01-10 University Of Pittsburgh-Of The Commonwealth System Of Higher Education Electrospinning of pvdf-hfp: novel composite polymer electrolytes (cpes) with enhanced ionic conductivities for lithium-sulfur batteries
WO2019066445A1 (en) * 2017-09-28 2019-04-04 주식회사 세븐킹에너지 Integrated all-solid-state secondary battery
CN114006027A (en) * 2020-07-27 2022-02-01 中国科学院苏州纳米技术与纳米仿生研究所 Molybdenum disulfide-based composite solid electrolyte, and preparation method and application thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030038610A1 (en) * 2001-03-30 2003-02-27 Munshi M. Zafar A. Structurally embedded intelligent power unit
US20080182176A1 (en) * 2007-01-25 2008-07-31 Doron Aurbach Rechargeable magnesium battery
WO2019010474A1 (en) * 2017-07-07 2019-01-10 University Of Pittsburgh-Of The Commonwealth System Of Higher Education Electrospinning of pvdf-hfp: novel composite polymer electrolytes (cpes) with enhanced ionic conductivities for lithium-sulfur batteries
WO2019066445A1 (en) * 2017-09-28 2019-04-04 주식회사 세븐킹에너지 Integrated all-solid-state secondary battery
CN114006027A (en) * 2020-07-27 2022-02-01 中国科学院苏州纳米技术与纳米仿生研究所 Molybdenum disulfide-based composite solid electrolyte, and preparation method and application thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
AJAY PERI, SAIKRISHNAN MADHAVAN, BHARTI SINGH: "《Investigation of the enhancement in the b-phase of PVDF as a functionof MoSe2 concentration and its effect on the piezoelectric performance of the nanogenerator》", 《MATERIALS TODAY: PROCEEDINGS》, vol. 47, pages 4796 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116742107A (en) * 2023-07-31 2023-09-12 武汉中科先进材料科技有限公司 Composite solid electrolyte membrane for lithium metal negative electrode and preparation method thereof
CN116742107B (en) * 2023-07-31 2024-03-26 武汉中科先进材料科技有限公司 Composite solid electrolyte membrane for lithium metal negative electrode and preparation method thereof

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