CN111900333A - Lithium-free dendritic crystal anode with carbon nanotube film directly compounded with molten lithium metal and preparation method thereof - Google Patents

Lithium-free dendritic crystal anode with carbon nanotube film directly compounded with molten lithium metal and preparation method thereof Download PDF

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CN111900333A
CN111900333A CN202010821748.3A CN202010821748A CN111900333A CN 111900333 A CN111900333 A CN 111900333A CN 202010821748 A CN202010821748 A CN 202010821748A CN 111900333 A CN111900333 A CN 111900333A
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lithium
carbon nanotube
nanotube film
film
anode
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CN111900333B (en
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吴子平
王志勇
卢忠旭
胡英燕
尹艳红
刘先斌
黎业生
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Jiangxi University of Science and Technology
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Abstract

A lithium dendrite-free anode with a carbon nanotube film directly compounded with molten lithium metal and a preparation method thereof relate to a lithium dendrite-free anode obtained by directly infiltrating liquid lithium into a carbon nanotube film and a preparation method thereof. The temperature gradient is regulated and controlled to enable the liquid lithium metal and the upper carbon nanotube film to generate negative Gibbs free energy, and then the liquid lithium metal is driven to infiltrate into the upper carbon nanotube film. The composite material formed by directly and uniformly coating or pouring liquid lithium into the carbon nano tube film can be used as the lithium dendrite-free lithium metal battery anode with a three-dimensional nano structure. Under the condition of ultrahigh current density, the lithium-carbon nanotube film composite anode can realize the stable operation of a symmetrical battery without lithium dendrites, and can realize the cycling stability of the battery under high multiplying power when the lithium-carbon nanotube film composite anode is used as an anode and applied to a lithium-sulfur full battery. The preparation process is simple and practical, is convenient to regulate and control, is easy to realize large-scale commercial production, and can effectively inhibit lithium dendrites, thereby providing guarantee for expanding the application field of the lithium metal battery.

Description

Lithium-free dendritic crystal anode with carbon nanotube film directly compounded with molten lithium metal and preparation method thereof
Technical Field
The invention relates to a lithium dendrite-free anode obtained by directly infiltrating liquid lithium into a carbon nanotube film and a preparation method thereof. In particular to a lithium dendrite-free composite anode with a three-dimensional nano structure, which can be applied to a lithium metal battery and is obtained by controlling temperature gradient and realizing direct infiltration of molten lithium metal into a carbon nanotube film. The short circuit risk of the existing lithium metal battery with high specific energy caused by lithium dendrites is greatly reduced, and the wide application of the lithium metal battery can be promoted.
Background
Since the commercialization of Lithium Ion Batteries (LIBs) in 1991, advanced energy storage technology has enabled our lives to be more convenient and cleaner in energy utilization. However, due to the lower theoretical energy density limit of intercalation electrochemistry in a lithium ion system, the improvement of the volume and weight energy density of the used battery is severely restricted, so that the next generation rechargeable battery needs to be transited from an intercalation chemical system to a chemical conversion system so as to adapt to the urgent requirements of portable electronic products or electric automobiles and the like on high-specific-energy storage devices.
Of all currently available candidate anode materials for chemical conversion batteries, lithium metal is the most promising candidate with an extremely high theoretical specific capacity (3860 mAh g)-1) And the lowest electrochemical reactionThe potential (for a standard hydrogen electrode-3.04V) is applied. However, the serious safety problem and the low cycle efficiency are two key problems to be solved in the practical application of the lithium metal battery. Lithium dendrites are generated because lithium ions tend to grow reductively in an acicular or dendritic manner during electrochemical deposition on a lithium metal anode. The dendrite grows continuously and is easy to pierce through the diaphragm, so that the battery is short-circuited, and finally safety accidents are caused. In addition, during the process of the lithium ion cycle deposition stripping, the electrolyte can be irreversibly consumed by the dendritic lithium dendrites which are continuously grown. And accumulation of an insulating Solid Electrolyte Interphase (SEI) layer can generate a large amount of 'dead lithium', so that the electrolyte is dried up, the internal resistance is increased, and the coulombic efficiency of the battery is reduced until the battery fails.
In recent years, in order to meet the challenge, researchers have proposed a series of strategies for inhibiting the growth of lithium dendrites, such as Goodenough et al published Fluorine-doped inorganic electrolyte strategies on page 34, 9965 to 9968 of Angewandte chemical-International Edition (German applied chemistry) 2016, book 55, and proposed a Fluorine-doped solid electrolyte strategy; zhang et al, Electrolysis activated fast charging and stable cycling electrolytes disclosed in Nature Energy, 2017, Vol.2, pp.3, 17012-1 to 17012-8, propose to add new Electrolyte additives; cui et al, published in Nature Nanotechnology, volume 11, pp.7, 626 to 632, Nature Nanotechnology, Nature, Nanotechnology, and the strategies for constructing three-dimensional lithium metal host frameworks, etc., were proposed in Layered reduced graphene oxide with nanoscopic interface gates as a stable host for lithium metals. The strategy for constructing the three-dimensional lithium metal deposition framework can effectively hinder the growth of anode dendrites by regulating and controlling the uniform deposition of lithium ions. Carbon nanotubes are ideal lithium metal three-dimensional framework candidate materials recognized by scientists due to their interconnected network nanostructure, low redox potential, high surface area and sufficient lithium metal accommodating space. In addition, the carbon nanotube film can divide high-density lithium metal into a plurality of smaller areas, so that the current density can be effectively reduced, and the volume expansion can be inhibited.
The method which is most easy to realize the compounding of the lithium metal and the carbon material at present is a melt perfusion method. However, most available carbon material hosts, including carbon nanotubes, are not wetted by molten lithium. This severely hampers the application of carbon materials to the three-dimensional carbon host of lithium metal anodes. To solve this problem, scientists have modified the surface of the carbon host, such as coating a lithium-philic substance on a three-dimensional carbon host as proposed by Cui et al, comprehensive metal and salt fusion of lithium inter a 3D conditioning and subsequent with lithium grafting, published by Cui et al, Proceedings of the National Academy of Sciences of the United States of America, 2016, pp 11, 2862 to 2867, pp 113, respectively. This, while effective in solving the problem of wettability of the surface, also causes other problems such as the addition of a lithium-philic substance introduces impurities that may cause side reactions. On one hand, the products have larger weight and volume due to the recombination of the lithium metal and the lithium metal through chemical reaction, occupy the internal space of a three-dimensional host and reduce the energy density of the battery; on the other hand, impurities may participate in electrochemical reaction, consume electrolyte, and reduce battery capacity and cycle stability. Therefore, the direct application of the molten lithium metal compounded with the carbon material as a dendrite-free anode has important significance for the development of lithium metal batteries.
Disclosure of Invention
The invention aims at the problems and provides a lithium dendrite-free anode obtained by directly infiltrating liquid lithium into a carbon nanotube film and a related preparation method thereof. Through heat exchange with the environment by the carbon nanotubes having excellent thermal conductivity, there is a temperature gradient in a direction perpendicular to the surface of the material. The temperature gradient is regulated and controlled to enable the liquid lithium metal and the upper carbon nanotube film to generate negative Gibbs free energy, and then the liquid lithium metal is driven to infiltrate into the upper carbon nanotube film. The composite material formed by directly and uniformly coating or pouring liquid lithium into the carbon nano tube film can be used as the lithium dendrite-free lithium metal battery anode with a three-dimensional nano structure. Under the condition of ultrahigh current density, the lithium-carbon nanotube film composite anode can realize the stable operation of a symmetrical battery without lithium dendrites, and can realize the cycling stability of the battery under high multiplying power when the lithium-carbon nanotube film composite anode is used as an anode and applied to a lithium-sulfur full battery. The preparation process is simple and practical, is convenient to regulate and control, is easy to realize large-scale commercial production, and can effectively inhibit lithium dendrites, thereby providing guarantee for expanding the application field of the lithium metal battery.
The purpose of the invention is realized by the following technical scheme.
A lithium dendrite-free anode obtained by directly infiltrating liquid lithium into a carbon nanotube film and a related preparation method thereof sequentially comprise the following steps:
step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material. Firstly, the thickness is 1-100 μm, the area is 100-900 cm2The carbon nanotube film of (a) serves as a three-dimensional carbon host backbone. Cutting the prepared carbon nanotube film into two pieces with equal area of 4-25 cm2The carbon nanotube film of (3). In a glove box (H)2O≤0.1ppm；O2Not more than 0.1 ppm), respectively attaching the two cut carbon nanotube films on the upper surface and the lower surface of the lithium foil with the same size, and finally obtaining the material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure.
And step two, realizing the infiltration and compounding of the molten lithium metal and the carbon nanotube film by temperature regulation. In a glove box (H)2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), one heating area is 100-400 cm2Is set at 175-400oAnd C, placing the sandwich structure material prepared in the step one on a heater. Wherein the temperature of the lower carbon nanotube film is 180-oC, the temperature of the lithium foil in the middle layer is 180-oC, the temperature of the upper carbon nanotube film is 60-180 DEGoC. After the heat preservation time of 1-20 minutes, the carbon nanotube film on the upper surface of the lithium foil is soaked by liquid lithium, and the carbon nanotube film on the lower surface of the lithium foil is not soaked by lithium; and then the material is turned over to change the lower surface carbon nano film of the original lithium foil into the upper surface, and the upper surface carbon nano tube film is thoroughly soaked by lithium under the same heat preservation time. Finally obtaining the composite material with three-dimensional nano structure with the lithium metal and the carbon nano tube film which are compounded and integrated, wherein the volume of the lithium metal isThe ratio of the carbon nanotube-lithium composite material uniformly coated with lithium is kept between 10% and 99% with the change of the temperature and the time of the heater.
And step three, preparing a symmetrical battery and a lithium-sulfur battery. The preparation process of the symmetrical battery comprises the following steps: in a glove box (H) filled with high-purity argon gas2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), cutting a round electrode of the carbon nanotube film-lithium composite material uniformly coated with lithium prepared in the step two by using a die with the diameter of 4-20 mm, and using the round electrode as an anode of a symmetric battery; the lithium foil wafer with the diameter of 4-20 mm is used as the cathode of the symmetrical battery; the electrolyte consists of lithium salt, additive and solvent: with lithium trifluoromethanesulfonate (LiCF)3SO3) One of lithium bis (fluorosulfonyl) imide (LiFSI) and lithium 2- (trifluoromethylsulfonyl) imide (LiTFSI) is used as a lithium salt, one or more of ethylene glycol dimethyl ether (DME), 1, 3 Dioxolane (DOL), dimethyl sulfoxide (DMSO), Tetrahydrofuran (THF) and tetraethylene glycol dimethyl ether (TETRAGLYME) is used as a solvent, and one or more of lithium nitrate, silicon dioxide and thionyl chloride is used as an additive; and a Polyethylene (PE) film and a polypropylene (PP) film are taken as diaphragms to assemble the symmetrical battery.
The preparation process of the lithium-sulfur battery comprises the following steps: the anode, separator and electrolyte used in the lithium sulfur cell are the same as the materials used in the above-described symmetrical cell. The only difference between lithium sulfur batteries and symmetric batteries is the cathode material. The cathode plate of the lithium-sulfur battery is prepared by dropwise adding polysulfide onto one current collector of a carbon nanotube film, a graphene film, conductive carbon cloth and conductive fibers. The polysulfide is prepared by dissolving sulfur and lithium sulfide in a solution composed of lithium salt, additive and solvent, wherein the lithium salt is lithium trifluoromethane sulfonate (LiCF)3SO3) The lithium bis (fluorosulfonyl) imide (LiFSI) and the lithium 2- (trifluoromethylsulfonyl) imide (LiTFSI), wherein the solvent is one or more of ethylene glycol dimethyl ether (DME), 1, 3 Dioxolane (DOL), dimethyl sulfoxide (DMSO), Tetrahydrofuran (THF) and tetraethylene glycol dimethyl ether (TETRAGLYME), and the additive is one or more of lithium nitrate, silicon dioxide and thionyl chloride. Then at 40-80oCondition CStirring and heating for 4-36 h to directly react and synthesize polysulfide.
And step four, testing the battery performance. The symmetrical batteries are placed on a battery test cabinet to carry out constant current (0.1-100 mA) and constant capacity (0.1-200 mAh) circulation for 1-1000 times. The lithium ion repeat stripping/plating process was recorded. Compared with the overpotential of a symmetrical battery, the cycling overpotential of the symmetrical battery adopting the carbon nanotube film-lithium composite material as the anode is kept stable and lower than 0.2V all the time, while the overpotential of the symmetrical battery of the lithium foil anode is gradually increased along with the cycling, exceeds 0.4V, even reaches 1V to limit the overpotential, and the condition that the sudden overvoltage is reduced to be within 0.01V can occur, which indicates that the pure lithium foil anode can generate lithium dendrite to cause the short circuit of the battery, and dead lithium is accumulated to make the overpotential larger and larger. The carbon nanotube film-lithium composite material can effectively disperse current density, inhibit the growth of lithium dendrite and avoid short circuit. The lithium-sulfur battery is also placed on a battery test cabinet for testing the cycling stability by circulating for 1-1000 circles under constant current (0.01-10000 mA), wherein the set voltage interval is 1.5-3.0V. The lithium-sulfur battery adopting the carbon nanotube film-lithium composite material as the anode can be always stably circulated, and the specific capacity is 400-1400 mAh/g. The situation that the battery capacity is reduced to below 200 mAh/g in the lithium foil anode cycling process shows that the lithium foil anode has a short circuit problem caused by dendrite in the actual full battery application, and the composite anode adopting the carbon nanotube film as a three-dimensional host of the lithium metal can inhibit the lithium dendrite and guarantee the battery safety.
The invention has the following beneficial effects:
the carbon nanotube film is a host material with great prospect for inhibiting lithium dendrite problem of the lithium metal anode. However, the liquid lithium metal has poor wettability with carbon materials such as carbon cloth, carbon fiber paper, mesoporous carbon, electrospun carbon nanofibers, and carbon nanotube films, and thus the liquid lithium metal cannot be directly infused into a carbon host. The currently prevailing composite strategy is to coat the surface of the host material with a layer of lithium-philic interlayer material. However, the addition of a lithium-philic substance is equivalent to the introduction of an impurity which may bring about side reactions. On one hand, as the lithium metal is compounded through chemical reaction with the lithium metal, the reaction product has larger weight and volume, occupies the internal space of a three-dimensional host, and reduces the energy density of the battery; on the other hand, impurities may participate in electrochemical reactions, consuming electrolyte, reducing the capacity and cycling stability of the battery. Therefore, the direct application of the carbon material compounded with the molten lithium metal as a dendrite-free anode without coating a lithium-philic substance on a host has important significance for the development of lithium metal batteries. Compared with the existing method for coating a lithium-philic substance on a carbon host and then compounding lithium metal, the method has the advantages and beneficial effects. Firstly, the invention directly realizes the permeation of liquid lithium metal to the carbon nanotube film by using a metallurgical means, and the traditional means coats a lithium-philic substance which chemically reacts with lithium to realize the infiltration. No chemical reaction product impurity occupies a lithium storage space inside the carbon nanotube film, so that the advantages of a three-dimensional carbon nano host can be utilized to the maximum extent, and the energy density of the composite anode is remarkably improved; second, no chemical product impurities hinder the transport exchange of electrons between the carbon nanotubes and the lithium metal; thirdly, no impurity brings the risk of side reaction of the battery, so that the working voltage platform of the cathode is not influenced, and the stable operation of the battery is guaranteed; fourthly, the carbon nano tube has excellent conductivity, can effectively disperse current density and reduce polarization internal resistance of the battery. The carbon nanotube film is filled with nano-scale gaps, and the gaps can store a certain amount of electrolyte, so that the electrolyte is more fully contacted with lithium metal, and further, the ion transmission on the three-dimensional nano anode is quicker and the impedance is smaller.
In conclusion, the method does not consume lithium metal, does not generate impurities such as lithium oxide and the like, saves the lithium storage space of the three-dimensional host, improves the energy density, and does not bring side reaction in a lithium metal battery system. The composite material prepared by the method is quick, simple to regulate and control, and easy to realize large-scale commercial production, effectively inhibits lithium dendrites, and improves the safety guarantee of the application of the lithium metal battery.
Detailed Description
The following examples illustrate the invention in detail: the present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a process are given, but the scope of the present invention is not limited to the following embodiments.
Example 1
Step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material. Firstly, the film is prepared by chemical vapor deposition with the thickness of 50 μm and the area of 900 cm2The carbon nanotube film of (a) serves as a three-dimensional carbon host backbone. Cutting the prepared carbon nanotube film into two pieces with the same size and the area of 25 cm2The carbon nanotube film of (3). In a glove box (H)2O≤0.1 ppm；O2Not more than 0.1 ppm), respectively attaching the two cut carbon nanotube films on the upper surface and the lower surface of the lithium foil with the same size, and finally obtaining the material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure.
And step two, realizing the infiltration and compounding of the molten lithium metal and the carbon nanotube film by temperature gradient regulation. In a glove box (H)2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), one heating area is 100 cm2Is set at 180 deg.foAnd C, placing the sandwich structure material prepared in the step one on a heater. Wherein the temperature of the lower carbon nanotube film is 180 DEGoC, the temperature of the middle layer lithium foil is 180 DEGoC, the temperature of the upper carbon nanotube film is 90 DEGoC. After the heat preservation time of 10 minutes, the carbon nano tube film on the upper surface of the lithium foil is soaked by liquid lithium, and the carbon nano tube film on the lower surface of the lithium foil is not soaked by lithium; and then the material is turned over to change the lower surface carbon nano film of the original lithium foil into the upper surface, and the upper surface carbon nano tube film is thoroughly soaked by lithium under the same heat preservation time. Finally, the composite material with the three-dimensional nano structure, which is formed by compounding and integrating the lithium metal and the carbon nano tube film, is obtained, and the ratio of the volume of the lithium metal in the carbon nano tube-lithium composite material uniformly coated by the lithium is kept at 20%.
And step three, preparing a symmetrical battery and a lithium-sulfur battery. The preparation process of the symmetrical battery comprises the following steps: in a glove box (H) filled with high-purity argon gas2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), cutting a circular electrode of the carbon nanotube film-lithium composite material uniformly coated with lithium prepared in the step two by using a die with the diameter of 16 mm, and using the circular electrode as an anode of a symmetrical battery; a lithium foil wafer with the diameter of 16 mm is used as a cathode of the symmetrical battery; an electrolyte composed ofLithium salt, additive and solvent composition: one of 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI) is used as a lithium salt, ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL) are used as solvents, and lithium nitrate is used as an additive; and a polypropylene (PP) film is taken as a diaphragm to assemble the symmetrical battery.
The preparation process of the lithium-sulfur battery comprises the following steps: the anode, separator and electrolyte used in the lithium sulfur cell are the same as the materials used in the above-described symmetrical cell. The only difference between lithium sulfur batteries and symmetric batteries is the cathode material. The cathode plate of the lithium-sulfur battery is prepared by dropwise adding polysulfide onto one current collector of a carbon nanotube film, a graphene film, conductive carbon cloth and conductive fibers. The polysulfide is prepared by dissolving sulfur and lithium sulfide into a solution composed of lithium salt, additive and solvent, wherein the lithium salt is 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI), the solvent is ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL), and the additive is lithium nitrate. Then at 50oAnd C, stirring and heating for 12 hours under the condition of C, and directly reacting to synthesize polysulfide.
And step four, testing the battery performance. The symmetrical batteries were placed in a battery test cabinet for 300 cycles of constant current (4 mA), constant capacity (2 mAh). The lithium ion repeat stripping/plating process was recorded. Compared with the overpotential of a symmetrical battery, the cycling overpotential of the symmetrical battery using the carbon nanotube film-lithium composite material as the anode is kept stable and is lower than 0.04V, while the overpotential of the symmetrical battery of the lithium foil anode is gradually increased along with the cycling and exceeds 0.1V, which indicates that the pure lithium foil anode can generate lithium dendrite to cause the short circuit of the battery, and dead lithium is accumulated to make the overpotential larger and larger. The carbon nanotube film-lithium composite material can effectively disperse current density, inhibit the growth of lithium dendrite and avoid short circuit. The lithium sulfur battery is also placed on a battery test cabinet under the condition of constant current (2.1 mA) and circulated for 200 circles, wherein the set voltage interval is 1.8-2.8V. It was found that the lithium-sulfur battery using the carbon nanotube film-lithium composite as the anode was able to continue stable cycling with a slow decrease in specific capacity from 1000 mAh/g to 680 mAh/g. And the battery capacity is suddenly reduced from 600 mAh/g to 150 mAh/g when the lithium foil anode is circulated to 63 circles, which indicates that the lithium foil anode has the short circuit problem caused by dendrite in the actual full battery application, and the composite anode adopting the carbon nanotube film as the three-dimensional host of the lithium metal can inhibit the lithium dendrite and ensure the battery safety.
Example 2
Step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material. Firstly, the film is prepared by chemical vapor deposition with the thickness of 40 mu m and the area of 500 cm2The carbon nanotube film of (a) serves as a three-dimensional carbon host backbone. Cutting the prepared carbon nanotube film into two pieces with the same size and the area of 10 cm2The carbon nanotube film of (3). In a glove box (H)2O≤0.1 ppm；O2Not more than 0.1 ppm), respectively attaching the two cut carbon nanotube films on the upper surface and the lower surface of the lithium foil with the same size, and finally obtaining the material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure.
And step two, realizing the infiltration and compounding of the molten lithium metal and the carbon nanotube film by temperature gradient regulation. In a glove box (H)2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), one heating area is 200 cm2Is set at 230oAnd C, placing the sandwich structure material prepared in the step one on a heater. Wherein the temperature of the lower carbon nanotube film is 225oC, the temperature of the middle layer lithium foil is 210oC, the temperature of the upper carbon nanotube film is 124oC. After the heat preservation time of 5 minutes, the carbon nano tube film on the upper surface of the lithium foil is soaked by liquid lithium, and the carbon nano tube film on the lower surface of the lithium foil is not soaked by lithium; and then the material is turned over to change the lower surface carbon nano film of the original lithium foil into the upper surface, and the upper surface carbon nano tube film is thoroughly soaked by lithium under the same heat preservation time. Finally, the composite material with the three-dimensional nano structure, which is formed by compounding and integrating the lithium metal and the carbon nano tube film, is obtained, and the ratio of the volume of the lithium metal in the carbon nano tube-lithium composite material uniformly coated with lithium is kept at 40%.
And step three, preparing a symmetrical battery and a lithium-sulfur battery. The preparation process of the symmetrical battery comprises the following steps: in a glove box (H) filled with high-purity argon gas2O≤0.1 ppm；O2Not more than 0.1 ppm), to the preparation of the second stepThe carbon nanotube film-lithium composite material uniformly coated with lithium is cut into a circular electrode by using a die with the diameter of 16 mm, and the circular electrode is used as the anode of a symmetrical battery; a lithium foil wafer with the diameter of 16 mm is used as a cathode of the symmetrical battery; the electrolyte consists of lithium salt, additive and solvent: one of 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI) is used as a lithium salt, ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL) are used as solvents, and lithium nitrate is used as an additive; and a polypropylene (PP) film is taken as a diaphragm to assemble the symmetrical battery.
The preparation process of the lithium-sulfur battery comprises the following steps: the anode, separator and electrolyte used in the lithium sulfur cell are the same as the materials used in the above-described symmetrical cell. The only difference between lithium sulfur batteries and symmetric batteries is the cathode material. The cathode plate of the lithium-sulfur battery is prepared by dropwise adding polysulfide onto one current collector of a carbon nanotube film, a graphene film, conductive carbon cloth and conductive fibers. The polysulfide is prepared by dissolving sulfur and lithium sulfide into a solution composed of lithium salt, additive and solvent, wherein the lithium salt is 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI), the solvent is ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL), and the additive is lithium nitrate. Then at 50oAnd C, stirring and heating for 12 hours under the condition of C, and directly reacting to synthesize polysulfide.
And step four, testing the battery performance. The symmetrical batteries were placed in a battery test cabinet for 300 cycles of constant current (4 mA), constant capacity (2 mAh). The lithium ion repeat stripping/plating process was recorded. Compared with the overpotential of a symmetrical battery, the cycling overpotential of the symmetrical battery using the carbon nanotube film-lithium composite material as the anode is kept stable and is lower than 0.06V, while the overpotential of the symmetrical battery of the lithium foil anode is gradually increased along with the cycling and exceeds 0.12V, which indicates that the pure lithium foil anode can generate lithium dendrite to cause the short circuit of the battery, and dead lithium is accumulated to make the overpotential larger and larger. The carbon nanotube film-lithium composite material can effectively disperse current density, inhibit the growth of lithium dendrite and avoid short circuit. The lithium sulfur battery is also placed on a battery test cabinet under the condition of constant current (2.1 mA) and circulated for 200 circles, wherein the set voltage interval is 1.8-2.8V. It was found that the lithium-sulfur battery using the carbon nanotube film-lithium composite as the anode was able to continue stable cycling with a slow drop in specific capacity from 900 mAh/g to 560 mAh/g. When the lithium foil anode is cycled to 57 circles, the capacity of the battery is suddenly reduced from 700 mAh/g to 120 mAh/g, which indicates that the lithium foil anode has a short circuit problem caused by dendrite in the actual full battery application, and the composite anode adopting the carbon nanotube film as the three-dimensional host of the lithium metal can inhibit the lithium dendrite and ensure the safety of the battery.
Example 3.
Step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material. Firstly, the film is prepared by a chemical vapor deposition method, the thickness of the film is 60 mu m, and the area of the film is 400 cm2The carbon nanotube film of (a) serves as a three-dimensional carbon host backbone. Cutting the prepared carbon nanotube film into two pieces with the same size and the area of 16 cm2The carbon nanotube film of (3). In a glove box (H)2O≤0.1 ppm；O2Not more than 0.1 ppm), respectively attaching the two cut carbon nanotube films on the upper surface and the lower surface of the lithium foil with the same size, and finally obtaining the material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure.
And step two, realizing the infiltration and compounding of the molten lithium metal and the carbon nanotube film by temperature gradient regulation. In a glove box (H)2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), one heating area is 100 cm2Is set at a heater temperature of 280oAnd C, placing the sandwich structure material prepared in the step one on a heater. Wherein the temperature of the lower carbon nanotube film is 270 deg.CoC, the temperature of the lithium foil of the middle layer is 263oC, the temperature of the upper carbon nanotube film is 140 DEGoC. After the heat preservation time of 3 minutes, the carbon nano tube film on the upper surface of the lithium foil is soaked by liquid lithium, and the carbon nano tube film on the lower surface of the lithium foil is not soaked by lithium; and then the material is turned over to change the lower surface carbon nano film of the original lithium foil into the upper surface, and the upper surface carbon nano tube film is thoroughly soaked by lithium under the same heat preservation time. Finally, the composite material with the three-dimensional nano structure, which is formed by compounding and integrating the lithium metal and the carbon nano tube film, is obtained, and the ratio of the volume of the lithium metal in the carbon nano tube-lithium composite material uniformly coated with lithium is kept at 60 percent.
And step three, preparing a symmetrical battery and a lithium-sulfur battery. The preparation process of the symmetrical battery comprises the following steps: in a glove box (H) filled with high-purity argon gas2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), cutting a circular electrode of the carbon nanotube film-lithium composite material uniformly coated with lithium prepared in the step two by using a die with the diameter of 16 mm, and using the circular electrode as an anode of a symmetrical battery; a lithium foil wafer with the diameter of 16 mm is used as a cathode of the symmetrical battery; the electrolyte consists of lithium salt, additive and solvent: one of 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI) is used as a lithium salt, ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL) are used as solvents, and lithium nitrate is used as an additive; and a polypropylene (PP) film is taken as a diaphragm to assemble the symmetrical battery.
The preparation process of the lithium-sulfur battery comprises the following steps: the anode, separator and electrolyte used in the lithium sulfur cell are the same as the materials used in the above-described symmetrical cell. The only difference between lithium sulfur batteries and symmetric batteries is the cathode material. The cathode plate of the lithium-sulfur battery is prepared by dropwise adding polysulfide onto one current collector of a carbon nanotube film, a graphene film, conductive carbon cloth and conductive fibers. The polysulfide is prepared by dissolving sulfur and lithium sulfide into a solution composed of lithium salt, additive and solvent, wherein the lithium salt is 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI), the solvent is ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL), and the additive is lithium nitrate. Then at 50oAnd C, stirring and heating for 12 hours under the condition of C, and directly reacting to synthesize polysulfide.
And step four, testing the battery performance. The symmetrical batteries were placed in a battery test cabinet for 300 cycles of constant current (4 mA), constant capacity (2 mAh). The lithium ion repeat stripping/plating process was recorded. Compared with the overpotential of a symmetrical battery, the cycling overpotential of the symmetrical battery using the carbon nanotube film-lithium composite material as the anode is kept stable and is lower than 0.05V, while the overpotential of the symmetrical battery of the lithium foil anode is gradually increased along with the cycling and exceeds 0.11V, which indicates that the pure lithium foil anode can generate lithium dendrite to cause the short circuit of the battery, and dead lithium is accumulated to make the overpotential larger and larger. The carbon nanotube film-lithium composite material can effectively disperse current density, inhibit the growth of lithium dendrite and avoid short circuit. The lithium sulfur battery is also placed on a battery test cabinet under the condition of constant current (2.1 mA) and circulated for 200 circles, wherein the set voltage interval is 1.8-2.8V. It was found that the lithium-sulfur battery using the carbon nanotube film-lithium composite as the anode was able to continue stable cycling with a slow decrease in specific capacity from 850 mAh/g to 500 mAh/g. And when the lithium foil anode is cycled to 76 circles, the battery capacity is suddenly reduced from 650 mAh/g to 140 mAh/g, which indicates that the lithium foil anode has a short circuit problem caused by dendrite in the actual full battery application, and the composite anode adopting the carbon nanotube film as the three-dimensional host of the lithium metal can inhibit lithium dendrite and ensure the battery safety.
Example 4.
Step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material. Firstly, the film is prepared by chemical vapor deposition with the thickness of 80 mu m and the area of 300 cm2The carbon nanotube film of (a) serves as a three-dimensional carbon host backbone. Cutting the prepared carbon nanotube film into two pieces with the same size and the area of 25 cm2The carbon nanotube film of (3). In a glove box (H)2O≤0.1 ppm；O2Not more than 0.1 ppm), respectively attaching the two cut carbon nanotube films on the upper surface and the lower surface of the lithium foil with the same size, and finally obtaining the material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure.
And step two, realizing the infiltration and compounding of the molten lithium metal and the carbon nanotube film by temperature gradient regulation. In a glove box (H)2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), one heating area is 300 cm2Is set at 320 deg.foAnd C, placing the sandwich structure material prepared in the step one on a heater. Wherein the temperature of the lower carbon nanotube film is 300 deg.CoC, temperature of the interlayer lithium foil is 287oC, the temperature of the upper carbon nanotube film is 150 DEGoC. After the heat preservation time of 2 minutes, the carbon nano tube film on the upper surface of the lithium foil is soaked by liquid lithium, and the carbon nano tube film on the lower surface of the lithium foil is not soaked by lithium; and then the material is turned over to change the lower surface carbon nano film of the original lithium foil into the upper surface, and the upper surface carbon nano tube film is thoroughly soaked by lithium under the same heat preservation time. Finally obtaining the lithium goldThe composite material with a three-dimensional nano structure is compounded and integrated with a carbon nano tube film, and the ratio of the volume of lithium metal in the carbon nano tube-lithium composite material uniformly coated with lithium is kept at 80%.
And step three, preparing a symmetrical battery and a lithium-sulfur battery. The preparation process of the symmetrical battery comprises the following steps: in a glove box (H) filled with high-purity argon gas2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), cutting a circular electrode of the carbon nanotube film-lithium composite material uniformly coated with lithium prepared in the step two by using a die with the diameter of 16 mm, and using the circular electrode as an anode of a symmetrical battery; a lithium foil wafer with the diameter of 16 mm is used as a cathode of the symmetrical battery; the electrolyte consists of lithium salt, additive and solvent: one of 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI) is used as a lithium salt, ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL) are used as solvents, and lithium nitrate is used as an additive; and a polypropylene (PP) film is taken as a diaphragm to assemble the symmetrical battery.
The preparation process of the lithium-sulfur battery comprises the following steps: the anode, separator and electrolyte used in the lithium sulfur cell are the same as the materials used in the above-described symmetrical cell. The only difference between lithium sulfur batteries and symmetric batteries is the cathode material. The cathode plate of the lithium-sulfur battery is prepared by dropwise adding polysulfide onto one current collector of a carbon nanotube film, a graphene film, conductive carbon cloth and conductive fibers. The polysulfide is prepared by dissolving sulfur and lithium sulfide into a solution composed of lithium salt, additive and solvent, wherein the lithium salt is 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI), the solvent is ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL), and the additive is lithium nitrate. Then at 50oAnd C, stirring and heating for 12 hours under the condition of C, and directly reacting to synthesize polysulfide.
And step four, testing the battery performance. The symmetrical batteries were placed in a battery test cabinet for 300 cycles of constant current (4 mA), constant capacity (2 mAh). The lithium ion repeat stripping/plating process was recorded. Compared with the overpotential of a symmetrical battery, the cycling overpotential of the symmetrical battery using the carbon nanotube film-lithium composite material as the anode is kept stable and is lower than 0.06V, while the overpotential of the symmetrical battery of the lithium foil anode is gradually increased along with the cycling and exceeds 0.1V, which indicates that the pure lithium foil anode can generate lithium dendrite to cause the short circuit of the battery, and dead lithium is accumulated to make the overpotential larger and larger. The carbon nanotube film-lithium composite material can effectively disperse current density, inhibit the growth of lithium dendrite and avoid short circuit. The lithium sulfur battery is also placed on a battery test cabinet under the condition of constant current (2.1 mA) and circulated for 200 circles, wherein the set voltage interval is 1.8-2.8V. It was found that the lithium-sulfur battery using the carbon nanotube film-lithium composite as the anode was able to continue stable cycling with a slow drop in specific capacity from 800 mAh/g to 400 mAh/g. When the lithium foil anode is circulated to 65 circles, the capacity of the battery is suddenly reduced from 630 mAh/g to 130 mAh/g, which indicates that the lithium foil anode has a short circuit problem caused by dendrite in the actual full battery application, and the composite anode adopting the carbon nanotube film as the three-dimensional host of the lithium metal can inhibit lithium dendrite and ensure the safety of the battery.
Example 5.
Step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material. Firstly, the film is prepared by a chemical vapor deposition method, the thickness of the film is 60 mu m, and the area of the film is 100 cm2The carbon nanotube film of (a) serves as a three-dimensional carbon host backbone. Cutting the prepared carbon nanotube film into two pieces with the same size and the area of 10 cm2The carbon nanotube film of (3). In a glove box (H)2O≤0.1 ppm；O2Not more than 0.1 ppm), respectively attaching the two cut carbon nanotube films on the upper surface and the lower surface of the lithium foil with the same size, and finally obtaining the material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure.
And step two, realizing the infiltration and compounding of the molten lithium metal and the carbon nanotube film by temperature gradient regulation. In a glove box (H)2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), one heating area is 200 cm2Is set at 360 deg.foAnd C, placing the sandwich structure material prepared in the step one on a heater. Wherein the temperature of the lower carbon nanotube film is 340oC, the temperature of the middle layer lithium foil is 320 DEGoC, the temperature of the upper carbon nanotube film is 160 DEGoC. After the heat preservation time of 1 minute, the carbon nano tube film on the upper surface of the lithium foil is soaked by the liquid lithium, and the carbon nano tube film on the lower surface of the lithium foilNot infiltrated by lithium; and then the material is turned over to change the lower surface carbon nano film of the original lithium foil into the upper surface, and the upper surface carbon nano tube film is thoroughly soaked by lithium under the same heat preservation time. Finally, the composite material with the three-dimensional nano structure, which is formed by compounding and integrating the lithium metal and the carbon nano tube film, is obtained, and the ratio of the volume of the lithium metal in the carbon nano tube-lithium composite material uniformly coated with lithium is kept at 95%.
And step three, preparing a symmetrical battery and a lithium-sulfur battery. The preparation process of the symmetrical battery comprises the following steps: in a glove box (H) filled with high-purity argon gas2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), cutting a circular electrode of the carbon nanotube film-lithium composite material uniformly coated with lithium prepared in the step two by using a die with the diameter of 16 mm, and using the circular electrode as an anode of a symmetrical battery; a lithium foil wafer with the diameter of 16 mm is used as a cathode of the symmetrical battery; the electrolyte consists of lithium salt, additive and solvent: one of 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI) is used as a lithium salt, ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL) are used as solvents, and lithium nitrate is used as an additive; and a polypropylene (PP) film is taken as a diaphragm to assemble the symmetrical battery.
The preparation process of the lithium-sulfur battery comprises the following steps: the anode, separator and electrolyte used in the lithium sulfur cell are the same as the materials used in the above-described symmetrical cell. The only difference between lithium sulfur batteries and symmetric batteries is the cathode material. The cathode plate of the lithium-sulfur battery is prepared by dropwise adding polysulfide onto one current collector of a carbon nanotube film, a graphene film, conductive carbon cloth and conductive fibers. The polysulfide is prepared by dissolving sulfur and lithium sulfide into a solution composed of lithium salt, additive and solvent, wherein the lithium salt is 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI), the solvent is ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL), and the additive is lithium nitrate. Then at 50oAnd C, stirring and heating for 12 hours under the condition of C, and directly reacting to synthesize polysulfide.
And step four, testing the battery performance. The symmetrical batteries were placed in a battery test cabinet for 300 cycles of constant current (4 mA), constant capacity (2 mAh). The lithium ion repeat stripping/plating process was recorded. Compared with the overpotential of a symmetrical battery, the cycling overpotential of the symmetrical battery using the carbon nanotube film-lithium composite material as the anode is kept stable and is lower than 0.07V, while the overpotential of the symmetrical battery of the lithium foil anode is gradually increased along with the cycling and exceeds 0.11V, which indicates that the pure lithium foil anode can generate lithium dendrite to cause the short circuit of the battery, and dead lithium is accumulated to make the overpotential larger and larger. The carbon nanotube film-lithium composite material can effectively disperse current density, inhibit the growth of lithium dendrite and avoid short circuit. The lithium sulfur battery is also placed on a battery test cabinet under the condition of constant current (2.1 mA) and circulated for 200 circles, wherein the set voltage interval is 1.8-2.8V. It was found that the lithium-sulfur battery using the carbon nanotube film-lithium composite as the anode was able to continue stable cycling with a slow drop in specific capacity from 820 mAh/g to 410 mAh/g. When the lithium foil anode is circulated to 67 circles, the capacity of the battery is suddenly reduced from 680 mAh/g to 170 mAh/g, which indicates that the lithium foil anode has a short circuit problem caused by dendrite in the actual full battery application, and the lithium dendrite can be inhibited by adopting the carbon nanotube film as the composite anode of the lithium metal three-dimensional host, so that the safety of the battery is guaranteed.
Example 6
Step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material. Firstly, the film is prepared by chemical vapor deposition with the thickness of 50 μm and the area of 900 cm2The carbon nanotube film of (a) serves as a three-dimensional carbon host backbone. Cutting the prepared carbon nanotube film into two pieces with the same size and the area of 25 cm2The carbon nanotube film of (3). In a glove box (H)2O≤0.1 ppm；O2Not more than 0.1 ppm), respectively attaching the two cut carbon nanotube films on the upper surface and the lower surface of the lithium foil with the same size, and finally obtaining the material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure.
And step two, realizing the infiltration and compounding of the molten lithium metal and the carbon nanotube film by temperature gradient regulation. In a glove box (H)2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), one heating area is 100 cm2Is set at 190 deg.foAnd C, placing the sandwich structure material prepared in the step one on a heater. Wherein the temperature of the lower carbon nanotube film is 187oC, temperature of intermediate layer lithium foilDegree is 183oC, the temperature of the upper carbon nanotube film is 110 DEGoC. After the heat preservation time of 10 minutes, the carbon nano tube film on the upper surface of the lithium foil is soaked by liquid lithium, and the carbon nano tube film on the lower surface of the lithium foil is not soaked by lithium; and then the material is turned over to change the lower surface carbon nano film of the original lithium foil into the upper surface, and the upper surface carbon nano tube film is thoroughly soaked by lithium under the same heat preservation time. Finally, the composite material with the three-dimensional nano structure, which is formed by compounding and integrating the lithium metal and the carbon nano tube film, is obtained, and the ratio of the volume of the lithium metal in the carbon nano tube-lithium composite material uniformly coated with lithium is kept at 40%.
And step three, preparing a symmetrical battery and a lithium-sulfur battery. The preparation process of the symmetrical battery comprises the following steps: in a glove box (H) filled with high-purity argon gas2O≤0.1 ppm；O2Less than or equal to 0.1 ppm), cutting a circular electrode of the carbon nanotube film-lithium composite material uniformly coated with lithium prepared in the step two by using a die with the diameter of 16 mm, and using the circular electrode as an anode of a symmetrical battery; a lithium foil wafer with the diameter of 16 mm is used as a cathode of the symmetrical battery; the electrolyte consists of lithium salt, additive and solvent: one of 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI) is used as a lithium salt, ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL) are used as solvents, and lithium nitrate is used as an additive; and a polypropylene (PP) film is taken as a diaphragm to assemble the symmetrical battery.
The preparation process of the lithium-sulfur battery comprises the following steps: the anode, separator and electrolyte used in the lithium sulfur cell are the same as the materials used in the above-described symmetrical cell. The only difference between lithium sulfur batteries and symmetric batteries is the cathode material. The cathode plate of the lithium-sulfur battery is prepared by dropwise adding polysulfide onto one current collector of a carbon nanotube film, a graphene film, conductive carbon cloth and conductive fibers. The polysulfide is prepared by dissolving sulfur and lithium sulfide into a solution composed of lithium salt, additive and solvent, wherein the lithium salt is 2- (trifluoromethyl sulfonyl) lithium imide (LiTFSI), the solvent is ethylene glycol dimethyl ether (DME) and 1, 3 Dioxolane (DOL), and the additive is lithium nitrate. Then at 50oAnd C, stirring and heating for 12 hours under the condition of C, and directly reacting to synthesize polysulfide.
And step four, testing the battery performance. The symmetrical cells were placed in a cell test cabinet for 300 cycles of constant current (40 mA), constant capacity (20 mAh). The lithium ion repeat stripping/plating process was recorded. Compared with the overpotential of a symmetrical battery, the cycling overpotential of the symmetrical battery using the carbon nanotube film-lithium composite material as the anode is kept stable and is lower than 0.1V, while the overpotential of the symmetrical battery of the lithium foil anode is gradually increased along with the cycling and exceeds 0.4V, and the potential suddenly rises to be more than 1V when the battery is cycled to the 93 rd circle, which indicates that the pure lithium foil anode can generate lithium dendrites and accumulate dead lithium to enable the overpotential to be larger and larger until the battery fails. The carbon nanotube film-lithium composite material can effectively disperse current density, inhibit the growth of lithium dendrite and avoid short circuit. The lithium sulfur battery is also placed on a battery test cabinet under the condition of constant current (2.1 mA) and circulated for 200 circles, wherein the set voltage interval is 1.8-2.8V. It was found that the lithium-sulfur battery using the carbon nanotube film-lithium composite as the anode was able to continue stable cycling with a slow drop in specific capacity from 850 mAh/g to 470 mAh/g. When the lithium foil anode is cycled to 64 circles, the capacity of the battery is suddenly reduced from 620 mAh/g to 160 mAh/g, which indicates that the lithium foil anode has a short circuit problem caused by dendrite in the actual full battery application, and the composite anode adopting the carbon nanotube film as the three-dimensional host of the lithium metal can inhibit the lithium dendrite and ensure the safety of the battery.

Claims (10)

1. A lithium dendrite-free anode with a carbon nanotube film directly compounded with molten lithium metal is characterized in that: through the heat exchange between the carbon nano tube and the environment, a temperature gradient exists in the direction vertical to the surface of the material, and the temperature gradient is regulated and controlled to enable the liquid lithium metal and the upper carbon nano tube film to generate negative Gibbs free energy, so that the liquid lithium metal is driven to infiltrate into the upper carbon nano tube film; the liquid lithium is directly and uniformly coated or poured into the composite material formed by the carbon nano tube film, and the lithium metal battery anode without lithium dendrite with the three-dimensional nano structure is obtained.
2. The carbon nanotube film direct recombination lithium dendrite-free anode of claim 1 wherein: the lithium dendrite-free anode is prepared by a preparation method comprising the following steps:
step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material: firstly, the thickness is 1-100 μm, the area is 100-900 cm2The prepared carbon nanotube film is cut into two pieces with equal area of 4-25 cm as three-dimensional carbon host framework2In the glove box, two carbon nanotube films with the same size are cut out and respectively attached to the upper surface and the lower surface of a lithium foil with the same size, and finally a material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure is obtained;
step two, realizing the infiltration and compounding of molten lithium metal and the carbon nanotube film by temperature regulation: in the glove box, a heating area of 100-2Is set at 175-400oC, placing the sandwich structure material prepared in the step one on a heater; after the heat preservation time of 1-20 minutes, the carbon nanotube film on the upper surface of the lithium foil is soaked by liquid lithium, and the carbon nanotube film on the lower surface of the lithium foil is not soaked by lithium; turning over the material to change the lower surface carbon nano film of the original lithium foil into an upper surface, and completely soaking the upper surface carbon nano tube film with lithium in the same heat preservation time; finally, the composite material with the three-dimensional nano structure, which is formed by compounding and integrating the lithium metal and the carbon nano tube film, is obtained and is used as the anode of the battery.
3. The carbon nanotube film direct recombination lithium dendrite-free anode of claim 2 wherein: and in the second step, the ratio of the volume of the lithium metal in the carbon nanotube-lithium composite material uniformly coated with lithium is kept between 10 and 99 percent along with the change of the temperature and the time of the heater.
4. The carbon nanotube film direct recombination lithium dendrite-free anode of claim 2 wherein: the heating temperature in the second step is set as follows: the temperature of the lower carbon nanotube film is 180 DEG 390 DEGoC, the temperature of the lithium foil in the middle layer is 180-oC, temperature of the upper carbon nanotube filmThe degree is 60-180oC。
5. The carbon nanotube film direct recombination lithium dendrite-free anode of claim 2 wherein: h in the glove box of the first step and the second step2O≤0.1 ppm；O2≤0.1 ppm。
6. A method for preparing a lithium dendrite-free anode by directly compounding a carbon nanotube film with molten lithium metal is characterized by comprising the following steps: through the heat exchange between the carbon nano tube and the environment, a temperature gradient exists in the direction vertical to the surface of the material, and the temperature gradient is regulated and controlled to enable the liquid lithium metal and the upper carbon nano tube film to generate negative Gibbs free energy, so that the liquid lithium metal is driven to infiltrate into the upper carbon nano tube film; the liquid lithium is directly and uniformly coated or poured into the composite material formed by the carbon nano tube film, and the lithium metal battery anode without lithium dendrite with the three-dimensional nano structure is obtained.
7. The method of claim 6, wherein the carbon nanotube film is directly combined with the molten lithium metal to form a lithium dendrite-free anode, and the method comprises the following steps: comprises the following steps:
step one, preparing a carbon nanotube film-lithium foil-carbon nanotube film sandwich structure material: firstly, the thickness is 1-100 μm, the area is 100-900 cm2The prepared carbon nanotube film is cut into two pieces with equal area of 4-25 cm as three-dimensional carbon host framework2In the glove box, two carbon nanotube films with the same size are cut out and respectively attached to the upper surface and the lower surface of a lithium foil with the same size, and finally a material of the carbon nanotube film-lithium foil-carbon nanotube film with a sandwich type structure is obtained;
step two, realizing the infiltration and compounding of molten lithium metal and the carbon nanotube film by temperature regulation: in the glove box, a heating area of 100-2Is set at 175-400oC, placing the sandwich structure material prepared in the step one on a heater;after the heat preservation time of 1-20 minutes, the carbon nanotube film on the upper surface of the lithium foil is soaked by liquid lithium, and the carbon nanotube film on the lower surface of the lithium foil is not soaked by lithium; turning over the material to change the lower surface carbon nano film of the original lithium foil into an upper surface, and completely soaking the upper surface carbon nano tube film with lithium in the same heat preservation time; finally, the composite material with the three-dimensional nano structure, which is formed by compounding and integrating the lithium metal and the carbon nano tube film, is obtained and is used as the anode of the battery.
8. The method of claim 7, wherein the carbon nanotube film is directly combined with the molten lithium metal to form a lithium dendrite-free anode, and the method comprises the following steps: and in the second step, the ratio of the volume of the lithium metal in the carbon nanotube-lithium composite material uniformly coated with lithium is kept between 10 and 99 percent along with the change of the temperature and the time of the heater.
9. The method of claim 7, wherein the carbon nanotube film is directly combined with the molten lithium metal to form a lithium dendrite-free anode, and the method comprises the following steps: the heating temperature in the second step is set as follows: the temperature of the lower carbon nanotube film is 180 DEG 390 DEGoC, the temperature of the lithium foil in the middle layer is 180-oC, the temperature of the upper carbon nanotube film is 60-180 DEGoC。
10. The method of claim 7, wherein the carbon nanotube film is directly combined with the molten lithium metal to form a lithium dendrite-free anode, and the method comprises the following steps: h in the glove box of the first step and the second step2O≤0.1 ppm；O2≤0.1 ppm。
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113380987A (en) * 2021-06-08 2021-09-10 复旦大学 Carbon nano tube buffer layer/sodium composite cathode and preparation method and application thereof
CN113471402A (en) * 2021-07-03 2021-10-01 江西理工大学 Preparation method of carbon nanotube/lithium vanadate composite membrane with multiple polarization centers and application of composite membrane in catalysis of lithium-sulfur battery reaction
CN113644246A (en) * 2021-08-15 2021-11-12 江西理工大学 Self-breaking silicon electrode based on continuous electric contact network and preparation method thereof
CN114551803A (en) * 2022-02-26 2022-05-27 宁德新能源科技有限公司 Three-dimensional gradient electrode for lithium metal cathode and preparation method thereof
CN114824184A (en) * 2021-01-29 2022-07-29 清华大学 Lithium metal anode and preparation method thereof
CN115020657A (en) * 2022-07-27 2022-09-06 西安交通大学 Alkali metal composite cathode and integrated preparation method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103384000A (en) * 2012-05-02 2013-11-06 现代自动车株式会社 Lithium electrode for lithium metal battery and method of manufacturing the lithium electrode
CN104925778A (en) * 2014-03-21 2015-09-23 中国科学院苏州纳米技术与纳米仿生研究所 Carbon nanotube microsphere and preparation method and application thereof
CN105789559A (en) * 2016-04-21 2016-07-20 清华大学 Flexible lithium metal cell negative pole and preparation method thereof
CN108365200A (en) * 2018-02-11 2018-08-03 清华大学 A kind of preparation method of compound lithium an- ode
CN110783548A (en) * 2019-11-07 2020-02-11 苏州第一元素纳米技术有限公司 Electrochemically active material and method for producing same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103384000A (en) * 2012-05-02 2013-11-06 现代自动车株式会社 Lithium electrode for lithium metal battery and method of manufacturing the lithium electrode
CN104925778A (en) * 2014-03-21 2015-09-23 中国科学院苏州纳米技术与纳米仿生研究所 Carbon nanotube microsphere and preparation method and application thereof
CN105789559A (en) * 2016-04-21 2016-07-20 清华大学 Flexible lithium metal cell negative pole and preparation method thereof
CN108365200A (en) * 2018-02-11 2018-08-03 清华大学 A kind of preparation method of compound lithium an- ode
CN110783548A (en) * 2019-11-07 2020-02-11 苏州第一元素纳米技术有限公司 Electrochemically active material and method for producing same

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114824184A (en) * 2021-01-29 2022-07-29 清华大学 Lithium metal anode and preparation method thereof
CN113380987A (en) * 2021-06-08 2021-09-10 复旦大学 Carbon nano tube buffer layer/sodium composite cathode and preparation method and application thereof
CN113471402A (en) * 2021-07-03 2021-10-01 江西理工大学 Preparation method of carbon nanotube/lithium vanadate composite membrane with multiple polarization centers and application of composite membrane in catalysis of lithium-sulfur battery reaction
CN113644246A (en) * 2021-08-15 2021-11-12 江西理工大学 Self-breaking silicon electrode based on continuous electric contact network and preparation method thereof
CN114551803A (en) * 2022-02-26 2022-05-27 宁德新能源科技有限公司 Three-dimensional gradient electrode for lithium metal cathode and preparation method thereof
CN115020657A (en) * 2022-07-27 2022-09-06 西安交通大学 Alkali metal composite cathode and integrated preparation method thereof
CN115020657B (en) * 2022-07-27 2024-01-30 西安交通大学 Alkali metal composite negative electrode and integrated preparation method thereof

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