CN114203975A - Method for improving cycle performance of lithium metal battery - Google Patents

Method for improving cycle performance of lithium metal battery Download PDF

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CN114203975A
CN114203975A CN202111501576.2A CN202111501576A CN114203975A CN 114203975 A CN114203975 A CN 114203975A CN 202111501576 A CN202111501576 A CN 202111501576A CN 114203975 A CN114203975 A CN 114203975A
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lithium metal
lithium
battery
metal battery
negative electrode
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曹瑞国
艾福平
揭育林
焦淑红
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University of Science and Technology of China USTC
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University of Science and Technology of China USTC
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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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention provides a method for improving the cycle performance of a lithium metal battery, which is characterized in that a lithium metal battery cathode is pretreated and then is used for assembling the lithium metal battery; the pretreatment of the lithium metal battery negative electrode comprises the following steps: and immersing the lithium metal negative electrode into a cyclic ether solution containing a fluorine lithium salt for reaction, and forming a protective layer on the surface of the lithium metal negative electrode. The invention can generate a faint yellow stable protective layer with high ionic conductivity on the surface of the lithium metal by reaction, has higher modulus and excellent flexibility, isolates the lithium metal from electrolyte, realizes the protection of a lithium metal electrode and the uniform deposition of lithium ions, inhibits the growth of dendrite, prolongs the service life of the lithium metal battery, and improves the cycle performance of the lithium metal battery. The preparation method is simple, low in cost, high in ionic conductivity and good in stability, and can be used for large-scale preparation.

Description

Method for improving cycle performance of lithium metal battery
Technical Field
The invention belongs to the technical field of lithium metal batteries, and particularly relates to a method for improving the cycle performance of a lithium metal battery.
Background
The energy density of the lithium battery is improved, and the lithium battery without dendrites is realized to meet the requirement of portable electronicsDevices, electric vehicles, and smart grids store the main avenues for ever-increasing energy demand. The metallic lithium has extremely high theoretical specific capacity (3860mAh g)-1) And extremely low electrochemical potentials (-3.04V vs standard hydrogen electrode), direct use of lithium metal as the negative electrode is considered the most attractive approach to develop advanced lithium metal batteries. However, since lithium metal and an electrolyte are easy to generate side reactions, dendritic lithium grows seriously, the Coulombic Efficiency (CE) of a lithium metal battery is reduced, the cycle performance is poor, and even potential safety hazards exist.
In recent years, in order to solve the above problems and to improve the stability and energy density of lithium metal batteries, various strategies have been devised, and the main strategies include: designing a lithium-philic matrix for storing lithium, selecting suitable electrolyte additives, transforming a separator, and constructing a stable solid electrolyte interface of high ionic conductivity. Wherein the stable solid electrolyte interface film plays an important role in stabilizing the performance of the lithium metal battery.
Since the formation and composition of the solid electrolyte interfacial film are key factors affecting the surface performance of the lithium metal electrode, one of the most effective methods for solving the above problems is to construct a protective layer similar to the solid electrolyte interfacial film on the surface of the lithium metal negative electrode, including an inorganic layer, an organic layer, and an inorganic-organic composite layer. The inorganic layer has a high Young modulus and a relatively high lithium ion conductivity, can physically inhibit the growth of dendrites, but is highly brittle, is generally spherical or island-shaped, and is easily damaged by generated interface stress in the deposition/stripping process, so that the service life of the lithium metal negative electrode is not ideal. Organic layers, on the other hand, possess so strong toughness that they can withstand unlimited volume changes of the lithium metal electrode, but their ionic conductivity is poor, generally resulting in high electrochemical polarization, and lack the ability to direct a uniform flux of lithium ions to the surface of the lithium metal negative electrode. Therefore, in order to overcome these disadvantages, it is necessary to develop a new protective layer combining the advantages of each of the organic layer and the inorganic layer to improve the cycle performance of the lithium metal battery.
Disclosure of Invention
The invention aims to provide a method for improving the cycle performance of a lithium metal battery.
The invention provides a method for improving the cycle performance of a lithium metal battery, which is characterized in that a lithium metal battery cathode is pretreated and then is used for assembling the lithium metal battery;
the pretreatment of the lithium metal battery negative electrode comprises the following steps:
and immersing the lithium metal negative electrode into a cyclic ether solution containing a fluorine lithium salt for reaction, and forming a protective layer on the surface of the lithium metal negative electrode.
Preferably, the fluorine-containing lithium salt is lithium trifluoromethanesulfonate.
Preferably, the cyclic ether is 1, 4-dioxane.
Preferably, the concentration of the fluorine-containing lithium salt in the cyclic ether solution of the fluorine-containing lithium salt is 0.05-0.2 mol/L.
Preferably, the concentration of the fluorine-containing lithium salt in the cyclic ether solution of the fluorine-containing lithium salt is 0.1-0.15 mol/L.
Preferably, the reaction temperature is 20-30 ℃; the reaction time is 8-15 hours.
Preferably, the protective layer contains an inorganic component and an organic component;
the inorganic component is one or more of lithium fluoride, lithium sulfide and lithium carbonate;
the organic component is R-Li and/or R-O-Li, wherein R is alkyl.
Preferably, the lithium metal battery negative electrode is metallic lithium.
The invention provides a method for improving the cycle performance of a lithium metal battery, which is characterized in that a lithium metal battery cathode is pretreated and then is used for assembling the lithium metal battery; the pretreatment of the lithium metal battery negative electrode comprises the following steps: and immersing the lithium metal negative electrode into a cyclic ether solution containing a fluorine lithium salt for reaction, and forming a protective layer on the surface of the lithium metal negative electrode. The invention adopts a simple and easy soaking method, the lithium metal electrode is soaked into 0.1M/L pretreatment solution formed by dissolving the prepared lithium trifluoromethanesulfonate in 1-4 dioxane for 10 hours, a faint yellow stable protective layer with high ionic conductivity is generated on the surface of the lithium metal by reaction, and meanwhile, the protective layer has higher modulus and excellent flexibility, isolates the lithium metal and electrolyte, realizes the protection of the lithium metal electrode and the uniform deposition of lithium ions, inhibits the growth of dendrites, prolongs the service life of the lithium metal battery, and improves the cycle performance of the lithium metal battery. The stable composite lithium metal cathode protective layer prepared by the invention has the advantages of simple preparation method, low cost, large-scale preparation, high ionic conductivity and good stability, and is an excellent strategy for solving the defects of serious dendritic crystal growth, poor cycle performance, low coulombic efficiency, potential safety hazard and the like of the conventional lithium metal battery.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a flow chart of the present invention for preparing a stable lithium metal negative electrode protection layer on a lithium metal surface;
FIG. 2 is a graph of voltage versus time for long cycling of an assembled lithium metal battery of example 1 of the present invention;
FIG. 3 is a graph of voltage versus time for long cycling of an assembled lithium metal battery of comparative example 1 of the present invention;
FIG. 4 is an SEM image of the surface of an anode of an assembled lithium metal battery of example 2 of the present invention during 500 cycles;
FIG. 5 is a graph of voltage versus time for long cycling of an assembled lithium metal battery of example 2 of the present invention;
FIG. 6 is an SEM image of the surface of an anode of an assembled lithium metal battery of comparative example 2 of the present invention at 500 cycles;
FIG. 7 is a graph of voltage versus time for long cycling of an assembled lithium metal battery of comparative example 2 of the present invention;
FIG. 8 is a graph of voltage versus time for long cycling of an assembled lithium metal battery of comparative example 3 of the present invention;
FIG. 9 is a graph of voltage versus time for long cycling of an assembled lithium metal battery of comparative example 4 of the present invention;
fig. 10 is a graph of specific capacity versus number of cycles for an assembled lithium metal battery of example 3 of the present invention;
fig. 11 is a graph of specific capacity versus number of cycles of an assembled lithium metal battery of comparative example 5 of the present invention.
Detailed Description
The invention provides a method for improving the cycle performance of a lithium metal battery, which is characterized in that a lithium metal battery cathode is pretreated and then is used for assembling the lithium metal battery;
the pretreatment of the lithium metal battery negative electrode comprises the following steps:
and immersing the lithium metal negative electrode into a cyclic ether solution containing a fluorine lithium salt for reaction, and forming a protective layer on the surface of the lithium metal negative electrode.
According to the invention, the cycle performance of the lithium metal battery is improved by preparing a protective layer on the surface of the lithium metal cathode, the generated protective layer enables the lithium metal cathode to be passivated uniformly, no side reaction occurs between the lithium metal and the organic electrolyte, the lithium ion transmission rate in the protective layer is improved, uniform lithium ion deposition is promoted without dendritic lithium growth, the cycle life of the lithium battery is prolonged, and the cycle performance of the lithium metal battery is improved.
The method comprises the steps of firstly preparing a pretreatment solution, wherein the pretreatment solution takes fluorine-containing lithium salt as a solute and cyclic ether as a solvent, the fluorine-containing lithium salt is preferably lithium trifluoromethanesulfonate, and the cyclic ether is preferably 1, 4-dioxane. The concentration of the fluorine-containing lithium salt in the pretreatment solution is preferably 0.05-0.2 mol/L, and more preferably 0.1-0.15 mol/L.
In the invention, the lithium metal battery negative electrode is preferably metal lithium, and the lithium metal battery negative electrode is immersed into the pretreatment solution and reacts at room temperature to form a protective layer on the surface of the lithium metal negative electrode.
In the present invention, the reaction time is preferably 8 to 15 hours, and more preferably 10 to 12 hours.
In the reaction process, metal lithium reacts with the pretreatment solution to form a protective layer, specifically, lithium trifluoromethanesulfonate reacts with metal lithium to generate lithium fluoride and lithium sulfide, and 1-4 dioxane and lithium trifluoromethanesulfonate react with metal lithium together to generate an organic component. The organic component includes R-Li and/or R-O-Li, where R is an alkyl group.
The invention uses the pretreated lithium metal battery cathode for assembling the lithium metal battery, and the lithium metal battery comprises a cathode material, an anode material, electrolyte and a diaphragm.
The electrolyte preferably comprises a solute, an additive and a solvent; the solute is lithium bistrifluoromethanesulfonylimide; the additive is lithium nitrate, and the solvent is a mixed solvent composed of 1, 3-dioxolane/glycol dimethyl ether according to the volume ratio of 1: 1. In the electrolyte, the concentration of solute is 0.5-2 mol/L, and more preferably 1-1.5 mol/L; the mass concentration of the additive is preferably 1-3%, and more preferably 2-2.5%.
In the present invention, the lithium metal battery may be a counter battery or a full battery, and preferably, the negative electrode material and the positive electrode material of the counter battery are both lithium metal electrodes; the separator for the cell is a carger 2325 separator.
Preferably, the negative electrode material of the full cell is a metal lithium electrode, and the diaphragm of the full cell is a kargerd 2325 diaphragm; the positive electrode material of the full cell is lithium iron phosphate, and the full cell is specifically prepared from the following components in percentage by weight: carbon black conductive agent: polyvinylidene fluoride (pvdf) 8:1: 1.
The invention provides a method for improving the cycle performance of a lithium metal battery, which is characterized in that a lithium metal battery cathode is pretreated and then is used for assembling the lithium metal battery; the pretreatment of the lithium metal battery negative electrode comprises the following steps: and immersing the lithium metal negative electrode into a cyclic ether solution containing a fluorine lithium salt for reaction, and forming a protective layer on the surface of the lithium metal negative electrode. The invention adopts a simple and easy soaking method, the lithium metal electrode is soaked into 0.1M/L pretreatment solution formed by dissolving the prepared lithium trifluoromethanesulfonate in 1-4 dioxane for 10 hours, a faint yellow stable protective layer with high ionic conductivity is generated on the surface of the lithium metal by reaction, and meanwhile, the protective layer has higher modulus and excellent flexibility, isolates the lithium metal and electrolyte, realizes the protection of the lithium metal electrode and the uniform deposition of lithium ions, inhibits the growth of dendrites, prolongs the service life of the lithium metal battery, and improves the cycle performance of the lithium metal battery. The stable composite lithium metal cathode protective layer prepared by the invention has the advantages of simple preparation method, low cost, large-scale preparation, high ionic conductivity and good stability, and is an excellent strategy for solving the defects of serious dendritic crystal growth, poor cycle performance, low coulombic efficiency, potential safety hazard and the like of the conventional lithium metal battery.
In order to further illustrate the present invention, the following will describe the method for improving the cycle performance of a lithium metal battery in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.
Example 1
Mixing fluorine-containing lithium salt lithium trifluoromethanesulfonate and cyclic ether 1, 4-dioxane to prepare a pretreatment solution with the concentration of 0.1 mol/L.
And fully immersing the lithium metal electrode into the pretreatment solution at room temperature for 10 hours, reacting on the surface of the lithium metal to generate a lithium metal negative electrode protective layer, and then rinsing and airing to form a new lithium metal negative electrode containing the protective layer.
Fig. 1 is a flow chart of the preparation of a lithium metal negative electrode with a stable protective layer.
Lithium bistrifluoromethanesulfonimide, 1, 3-dioxolane/ethylene glycol dimethyl ether (V: V ═ 1:1) and lithium nitrate were thoroughly mixed to prepare a lithium sulfur electrolyte containing 2% of a lithium nitrate additive at a concentration of 1 mol/L.
The electrode and electrolyte of the lithium metal battery prepared as described above and other necessary battery components, for example: a diaphragm (celgard 2325 diaphragm), a gasket, a battery shell and the like, and are assembled into a 2032 type pair battery.
The long cycle test current density was set to 0.5 mA-cm-2Specific capacity is set to 1mAh cm-2。
The prepared battery was subjected to a long cycle test according to the above-mentioned set conditions.
As can be seen from fig. 2, after the surface of the lithium metal negative electrode is covered with a stable protective layer, the long cycle life can reach 1300 hours, and the overpotential is also very low, specifically 35 mV.
Comparative example 1
Lithium bistrifluoromethanesulfonimide, 1, 3-dioxolane/ethylene glycol dimethyl ether (V: V ═ 1:1) and lithium nitrate were thoroughly mixed to prepare a lithium sulfur electrolyte containing 2% of a lithium nitrate additive at a concentration of 1 mol/L.
The above-prepared lithium metal battery electrolyte and general lithium metal electrode and other necessary battery components, for example: a diaphragm (celgard 2325 diaphragm), a gasket, a battery shell and the like, and are assembled into a 2032 type pair battery.
The long cycle test current density was set to 0.5 mA-cm-2Specific capacity is set to 1mAh cm-2。
The prepared battery was subjected to a long cycle test according to the above-mentioned set conditions.
As can be seen from fig. 3, the lithium metal electrode of the control group has a long cycle life of only 680 hours due to the absence of the stable protective layer prepared by us on the surface, and the overpotential is also higher than that of the experimental group, and is 70 mv. It is shown that the stable protective layer prepared by us can improve the cycle performance of the lithium metal battery.
Example 2
Lithium trifluoromethanesulfonate and 1, 4-dioxane were mixed to prepare a pretreatment solution having a concentration of 0.1 mol/L.
And fully immersing the lithium metal electrode into the pretreatment solution at room temperature for 10 hours, and reacting on the surface of the lithium metal to generate a protective layer to form a new lithium metal cathode containing the protective layer.
Lithium bistrifluoromethanesulfonimide, 1, 3-dioxolane/ethylene glycol dimethyl ether (V: V ═ 1:1) and lithium nitrate were thoroughly mixed to prepare a lithium sulfur electrolyte containing 2% of a lithium nitrate additive at a concentration of 1 mol/L.
The electrode and electrolyte of the lithium metal battery prepared as described above and other necessary battery components, for example: a diaphragm (celgard 2325 diaphragm), a gasket, a battery shell and the like, and are assembled into a 2032 type pair battery.
The long cycle test current density was set to 2mA cm-2Specific capacity is set to 1mAh cm-2。
The prepared battery was subjected to a long cycle test according to the above-mentioned set conditions.
Fig. 4 is an SEM image of the surface of the negative electrode of the cell at 500 cycles. It can be seen that the lithium metal is deposited very uniformly and smoothly on the surface.
As can be seen from fig. 5, after the surface of the lithium metal negative electrode is covered with a stable protective layer, the long cycle life can reach 1300 hours, the overpotential is also very low, specifically 60mV, and 89mV is 1400 cycles.
Comparative example 2
Lithium bistrifluoromethanesulfonimide, 1, 3-dioxolane/ethylene glycol dimethyl ether (V: V ═ 1:1) and lithium nitrate were thoroughly mixed to prepare a lithium sulfur electrolyte containing 2% of a lithium nitrate additive at a concentration of 1 mol/L.
The lithium metal battery electrolyte and the common lithium metal electrode prepared as described above and other necessary battery components, for example: a diaphragm (celgard 2325 diaphragm), a gasket, a battery shell and the like, and are assembled into a 2032 type pair battery.
The long cycle test current density was set to 2mA cm-2Specific capacity is set to 1mAh cm-2。
The prepared battery was subjected to a long cycle test according to the above-mentioned set conditions.
Fig. 6 is an SEM image of the negative electrode surface of the cell at 500 cycles. It can be seen that the lithium metal has formed a number of dendrites on the surface and that the deposit is unevenly smooth
As can be seen from fig. 7, the long cycle life of the control lithium metal electrode was only 400 hours due to the absence of the stable protective layer prepared by us on the surface, and the overpotential was also higher than that of the experimental group, and was 120mV, and at 1400 cycles, the overpotential reached nearly 300 mV. It is demonstrated that the stable protective layer prepared by the present application can indeed improve the cycle performance of lithium metal batteries.
Comparative example 3
Mixing lithium trifluoromethanesulfonate and ethylene glycol dimethyl ether to prepare a pretreatment solution with the concentration of 0.1M/L.
And fully immersing the lithium metal electrode into the pretreatment solution at room temperature for 10 hours, and reacting on the surface of the lithium metal to generate a protective layer to form a new lithium metal anode containing the protective layer.
Lithium bistrifluoromethanesulfonimide, 1, 3-dioxolane/ethylene glycol dimethyl ether (V: V ═ 1:1) and lithium nitrate were thoroughly mixed to prepare a lithium sulfur electrolyte containing a 2% lithium nitrate additive at a concentration of 1M/L.
The electrode and electrolyte of the lithium metal battery prepared as described above and other necessary battery components, for example: a diaphragm (celgard 2325 diaphragm), a gasket, a battery shell and the like, and are assembled into a 2032 type pair battery.
The long cycle test current density was set to 2mA cm-2Specific capacity is set to 1mAh cm-2。
The prepared battery was subjected to a long cycle test according to the above-mentioned set conditions.
As can be seen from FIG. 8, after the surface of the lithium metal anode is covered with a protective layer, the long cycle life can reach 1000+ hours, and the overpotential at this time is 170 mv.
Comparative example 4
Lithium trifluoromethanesulfonate and THF (tetrahydrofuran) were mixed to prepare a pretreatment solution having a concentration of 0.1 mol/L.
And fully immersing the lithium metal electrode into the pretreatment solution at room temperature for 10 hours, and reacting on the surface of the lithium metal to generate a protective layer to form a new lithium metal anode containing the protective layer.
Lithium bistrifluoromethanesulfonimide, 1, 3-dioxolane/ethylene glycol dimethyl ether (V: V ═ 1:1) and lithium nitrate were thoroughly mixed to prepare a lithium sulfur electrolyte containing 2% of a lithium nitrate additive at a concentration of 1 mol/L.
The electrode and electrolyte of the lithium metal battery prepared as described above and other necessary battery components, for example: a diaphragm (celgard 2325 diaphragm), a gasket, a battery shell and the like, and are assembled into a 2032 type pair battery.
The long cycle test current density was set to 2mA cm-2Specific capacity is set to 1mAh cm-2。
The prepared battery was subjected to a long cycle test according to the above-mentioned set conditions.
As can be seen from fig. 9, the lithium metal anode surface covered with a protective layer has a long cycle life of 1400 hours, and the overpotential is 120 mV. As can be seen from the several comparative examples and examples described above, the protective layer formed by the reaction of the pretreatment solution and lithium metal can indeed improve the cycle performance of the lithium metal battery. The solvent of the pretreatment solution is ether, and the best effect is achieved when the solvent is 1-4 dioxane.
Example 3
The positive electrode material of the lithium metal full battery is a lithium iron phosphate cathode, and is specifically composed of lithium iron phosphate: carbon black conductive agent: polyvinylidene fluoride (PVDF) 8:1: 1.
The negative electrode material of the lithium metal full cell uses lithium metal containing a stable protective layer as a negative electrode.
Lithium trifluoromethanesulfonate and 1, 4-dioxane were mixed to prepare a pretreatment solution having a concentration of 0.1 mol/L.
And fully immersing the lithium metal electrode into the pretreatment solution at room temperature for 10 hours, and reacting on the surface of the lithium metal to generate a protective layer to form a new lithium metal cathode containing the protective layer.
Lithium bistrifluoromethanesulfonimide, 1, 3-dioxolane/ethylene glycol dimethyl ether (V: V ═ 1:1) and lithium nitrate were thoroughly mixed to prepare a lithium sulfur electrolyte containing 2% of a lithium nitrate additive at a concentration of 1 mol/L.
The negative electrode, the cathode and the electrolyte of the lithium metal battery prepared as described above, and other necessary battery components, for example: a diaphragm (celgard 2325 diaphragm), a gasket, a battery shell and the like, and the 2032 type full battery is assembled.
The cycle test current density was set to 0.5C.
And carrying out cycle test on the prepared battery according to the set conditions, and testing the specific capacity and the capacity fading condition of the battery.
As can be seen from fig. 10, after a stable protective layer is covered on the surface of the lithium metal negative electrode, the lithium iron phosphate is used as the cathode of the battery to assemble the whole battery, and the current density of the battery is 0.5CThe initial specific capacity is 154mAh g-1And after 500 circles, the specific capacity is reduced to 154mAh g-1The capacity retention rate is as high as 95.45%.
Comparative example 5
The positive electrode material of the lithium metal full battery is a lithium iron phosphate cathode, and is specifically composed of lithium iron phosphate: carbon black conductive agent: polyvinylidene fluoride (PVDF) 8:1: 1.
Lithium bistrifluoromethanesulfonimide, 1, 3-dioxolane/ethylene glycol dimethyl ether (V: V ═ 1:1) and lithium nitrate were thoroughly mixed to prepare a lithium sulfur electrolyte containing 2% of a lithium nitrate additive at a concentration of 1 mol/L.
The cathode, electrolyte and general lithium metal negative electrode of the lithium metal battery prepared as described above, and other necessary battery components, for example: a diaphragm (celgard 2325 diaphragm), a gasket, a battery shell and the like, and the 2032 type full battery is assembled.
The cycle test current density was set to 0.5C.
And carrying out cycle test on the prepared battery according to the set conditions, and testing the specific capacity and the capacity fading condition of the battery.
As can be seen from fig. 11, the initial specific capacity of the full-cell assembled by the common lithium metal negative electrode and the lithium iron phosphate negative electrode is 147mAh g under the condition that the current density is 0.5C-1And the specific capacity rapidly drops after 200 circles, which shows that the specific capacity and the cycle life of the full battery can be improved by the lithium metal cathode with the stable protective layer prepared by the invention.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (8)

1. The method for improving the cycle performance of the lithium metal battery is characterized in that a lithium metal battery cathode is pretreated and then is used for assembling the lithium metal battery;
the pretreatment of the lithium metal battery negative electrode comprises the following steps:
and immersing the lithium metal negative electrode into a cyclic ether solution containing a fluorine lithium salt for reaction, and forming a protective layer on the surface of the lithium metal negative electrode.
2. The method of claim 1, wherein the fluorine-containing lithium salt is lithium trifluoromethanesulfonate.
3. The method of claim 2, wherein the cyclic ether is 1, 4-dioxane.
4. The method according to claim 3, wherein the concentration of the fluorine-containing lithium salt in the cyclic ether solution of the fluorine-containing lithium salt is 0.05 to 0.2 mol/L.
5. The method according to claim 4, wherein the concentration of the fluorine-containing lithium salt in the cyclic ether solution of the fluorine-containing lithium salt is 0.1 to 0.15 mol/L.
6. The method according to claim 5, wherein the temperature of the reaction is 20-30 ℃; the reaction time is 8-15 hours.
7. The method of claim 6, wherein the protective layer comprises an inorganic component and an organic component;
the inorganic component is one or more of lithium fluoride, lithium sulfide and lithium carbonate;
the organic component is R-Li and/or R-O-Li, wherein R is alkyl.
8. The method of any one of claims 1 to 7, wherein the negative electrode of the lithium metal battery is metallic lithium.
CN202111501576.2A 2021-12-09 2021-12-09 Method for improving cycle performance of lithium metal battery Pending CN114203975A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116247215A (en) * 2023-05-08 2023-06-09 广汽埃安新能源汽车股份有限公司 Lithium metal composite negative electrode, preparation method thereof, lithium metal battery and electric equipment

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190157714A1 (en) * 2016-11-24 2019-05-23 Lg Chem, Ltd. Pretreatment method for lithium electrode, and lithium metal battery
CN111293287A (en) * 2018-12-09 2020-06-16 中国科学院大连化学物理研究所 Lithium metal negative electrode and preparation and application thereof
CN113394456A (en) * 2021-06-11 2021-09-14 厦门大学 Lithium metal battery electrolyte additive and application thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190157714A1 (en) * 2016-11-24 2019-05-23 Lg Chem, Ltd. Pretreatment method for lithium electrode, and lithium metal battery
CN111293287A (en) * 2018-12-09 2020-06-16 中国科学院大连化学物理研究所 Lithium metal negative electrode and preparation and application thereof
CN113394456A (en) * 2021-06-11 2021-09-14 厦门大学 Lithium metal battery electrolyte additive and application thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116247215A (en) * 2023-05-08 2023-06-09 广汽埃安新能源汽车股份有限公司 Lithium metal composite negative electrode, preparation method thereof, lithium metal battery and electric equipment
CN116247215B (en) * 2023-05-08 2023-08-08 广汽埃安新能源汽车股份有限公司 Lithium metal composite negative electrode, preparation method thereof, lithium metal battery and electric equipment

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