阅读说明：本技术 金属锂@碳复合材料、锂金属阳极及其制备和应用 (Metal lithium @ carbon composite material, lithium metal anode, and preparation and application of lithium metal anode ) 是由 洪波 赖延清 范海林 覃昭铭 张治安 张凯 于 2018-08-29 设计创作，主要内容包括：本发明属于电池材料领域,具体公开了一种金属锂@碳复合材料,包括带有密闭的装填腔室的中空碳颗粒,以及填充在装填腔室内的金属锂；所述的中空碳颗粒的壳材料为石墨化碳。其优势在于,中空碳颗粒巨大的内部空腔提供了金属锂存储的位点,而中空碳颗粒表面的碳壁有效防止了金属锂与空气,电解液的直接接触,避免的界面反应的发生。得益于这些优势,中空碳颗粒保护的金属锂阳极可以在空气中稳定100h以上。本发明还公开了所述的金属锂@碳复合材料的制备和应用。(The invention belongs to the field of battery materials, and particularly discloses a metal lithium @ carbon composite material which comprises hollow carbon particles with a closed filling cavity and metal lithium filled in the filling cavity; the shell material of the hollow carbon particles is graphitized carbon. The hollow carbon particle has the advantages that the huge inner cavity of the hollow carbon particle provides a site for storing the metal lithium, and the carbon wall on the surface of the hollow carbon particle effectively prevents the metal lithium from directly contacting with air and electrolyte, so that the occurrence of interface reaction is avoided. Thanks to these advantages, the lithium metal anode protected by hollow carbon particles can be stable in air for more than 100 h. The invention also discloses a preparation method and application of the metal lithium @ carbon composite material.)

1. The metal lithium @ carbon composite material is characterized by comprising hollow carbon particles with a closed filling cavity and metal lithium filled in the filling cavity; the shell material of the hollow carbon particles is graphitized carbon.

2. The lithium metal @ carbon composite material as claimed in claim 1, wherein the lithium metal is filled into the loading chamber through a shell material of the hollow carbon particles;

preferably, the specific surface area of the metal lithium @ carbon composite material is 8-800 m²(ii)/g; preferably 60 to 400m²(ii)/g; more preferably 98 to 246m²/g；

Preferably, the shell thickness of the hollow carbon particles is 0.5-120 nm; preferably 3-60 nm; more preferably 14 to 35 nm.

3. The lithium metal @ carbon composite of claim 1, wherein the loading chamber comprises 40% to 99% of the total volume; preferably 50 to 95 percent; further preferably 65-80%;

the content of the metal lithium is 40-98 wt.%; preferably 50 to 95 wt.%.

4. The metallic lithium @ carbon composite material as claimed in any one of claims 1 to 3, wherein the shell material of the hollow carbon particles is nitrogen-doped graphitized carbon;

the shell material contains 0.05 to 10 at.% of nitrogen; preferably 0.2 to 6 at.%; further preferably 0.6 to 4.1 at.%.

5. A preparation method of the metal lithium @ carbon composite material as defined in any one of claims 1 to 4, comprising the following steps:

step (1): mixing hollow carbon particles with an adhesive, coating the mixture on a metal foil, taking the metal foil as a working electrode and taking metal lithium as a counter electrode, and depositing the metal lithium in the hollow carbon particles by an electrodeposition method;

step (2): and (2) carrying out ultrasonic treatment on the metal foil subjected to electrodeposition in the step (1) in an organic solution, and then obtaining the metal lithium @ carbon composite material.

6. The method of claim 5, wherein said binder is at least one of polyvinyl alcohol, polytetrafluoroethylene, sodium carboxymethylcellulose, polyvinylidene chloride, and SBR rubber;

the metal foil is at least one of copper foil, titanium foil, nickel foil or alloy foil thereof;

the electrodeposition method is at least one of constant direct current electrodeposition, pulse electrodeposition, constant potential deposition and cyclic voltammetry electrodeposition;

the organic solution is at least one of tetrahydrofuran, pyridine, pyrrole and corresponding alkyl derivatives thereof.

7. The method for preparing a lithium metal @ carbon composite material as defined in claim 5 or 6, wherein the hollow carbon particles are subjected to nitrogen doping treatment in advance before the step (1): the hollow carbon particle carbon is roasted in a nitrogen-containing atmosphere to obtain:

the nitrogen source of the nitrogen-containing atmosphere is nitrogen and/or ammonia;

the content of the nitrogen-doped atmosphere nitrogen source is 5-95 vol%; preferably 15 to 75 vol.%;

the roasting temperature is 600-1200 ℃; preferably 700-1100 ℃;

the roasting time is 0.4-20 h; preferably 0.6-15 h.

8. A carbon composite planar lithium metal anode characterized by: the active layer is compounded on the surface of the flat metal current collector; the active layer comprises the metal lithium @ carbon composite material as defined in any one of claims 1 to 4 or the metal lithium @ carbon composite material prepared by the preparation method as defined in any one of claims 5 to 7.

9. A preparation method of a carbon composite plane metal lithium anode is characterized by comprising the following steps: mixing hollow carbon particles with an adhesive, coating the mixture on a metal foil, taking the metal foil as a working electrode and taking metal lithium as a counter electrode, and depositing the metal lithium in the hollow carbon particles by an electrodeposition method; preparing the carbon composite planar lithium metal anode;

or, the metal lithium @ carbon composite material as defined in any one of claims 1 to 4 or the metal lithium @ carbon composite material as defined in any one of claims 5 to 7 is directly pressed on a metal plane current collector to obtain the carbon composite plane metal lithium anode.

10. The application of the metal lithium @ carbon composite material as defined in any one of claims 1-4 or the metal lithium @ carbon composite material prepared by the preparation method as defined in any one of claims 5-7 is characterized in that the metal lithium @ carbon composite material is used as a negative electrode active component for preparing a lithium ion battery or a lithium metal battery;

preferably, the lithium metal battery is a lithium oxygen battery, a lithium sulfur battery, a lithium selenium battery, a lithium tellurium battery, a lithium iodine battery, a lithium carbon dioxide battery or a lithium nitrogen battery.

Technical Field

The invention belongs to the field of energy storage devices, and particularly relates to preparation and application of air-stable lithium anode particles.

Background

The metal lithium is praised as a material similar to a holy cup in the lithium battery industry by virtue of extremely high theoretical specific capacity and the most negative electrode potential. The replacement of the existing graphite cathode by the metal lithium cathode is a necessary way for the industry of future lithium batteries. However, the high activity of the lithium metal negative electrode makes it very reactive to nitrogen, oxygen, carbon dioxide, water vapor, etc. in the air. These irreversible reactions pose a significant safety risk to the production of lithium batteries. Meanwhile, the lithium ion battery can not avoid continuous reaction with a solvent and an additive in an electrolyte, and the SEI film on the surface of the lithium metal is continuously generated, damaged and accumulated in the process of lithium deposition/dissolution, so that the low coulombic efficiency is finally caused, and the growth of lithium dendrites can not be controlled.

Therefore, the construction of stable lithium anodes, particularly the realization of lithium anodes stable in air, is a hot point and difficulty of research in the academic and industrial circles at present. Lithium metal can be protected from air corrosion for a short time by structuring a layer of lithium fluoride on the surface of commercial lithium powder. Such as Woo Young Yoon et al [ S. -T.Hong, J. -S.Kim, S. -J.Lim, W.Y.Yoon, Surface characterization of emulsified lithium powder electrode, electrochemical Acta 50(2-3) (2004) 535. 539.]By LiPF₆The lithium fluoride coated lithium powder anode is obtained by coating the lithium powder as a fluorine source, so that the performance of the lithium cathode is greatly improved. However, lithium fluoride is very deliquescent, resulting in complete oxidation of such lithium anodes after exposure to air for several hours. At the same time, the lower ionic conductivity of lithium fluoride also leads to an increase in the polarization of the cell, making it difficult to obtain a true polarization in the battery worldApplication is carried out.

Disclosure of Invention

Aiming at the problems commonly existing in a lithium metal anode, the invention aims to provide an air-stable lithium metal @ carbon composite material.

The second purpose of the invention is to provide a preparation method of the metal lithium @ carbon composite material.

The third purpose of the invention is to provide an application of the metal lithium @ carbon composite material in the field of metal lithium batteries or lithium ion batteries.

The fourth purpose of the invention is to provide a carbon composite planar metallic lithium anode added with the metallic lithium @ carbon composite material.

The fifth purpose of the invention is to provide a preparation method of the carbon composite plane metallic lithium anode.

The sixth purpose of the invention is to provide the application of the carbon composite planar metallic lithium anode of the metallic lithium @ carbon composite material as an electrode material.

A seventh object of the present invention is to provide a lithium metal battery equipped with said lithium metal @ carbon composite.

A lithium metal @ carbon composite comprising hollow carbon particles with a closed loading chamber (also referred to as a self-contained loading chamber), and lithium metal filled in the loading chamber;

the shell material (shell material) of the hollow carbon particles is graphitized carbon.

The hollow carbon particles of the present invention have a closed filling chamber, and the closed filling chamber means that the filling chamber is blocked (closed) from the external environment by the carbon shell of the hollow carbon particles. The metal lithium @ carbon composite material has a core-shell structure, wherein the core is made of metal lithium, the shell is the graphitized carbon, and the shell coats the core, so that the core is free from the influence of materials with atomic radii larger than the graphitized carbon, such as outside air and the like. The core and shell are allowed to have a void or complete contact (no void).

According to the metal lithium @ carbon composite material, the filling chamber is an independent chamber surrounded by graphitized carbon (shell layer).

The lithium metal is filled into the filling chamber through the shell material of the hollow carbon particles.

Preferably, the specific surface area of the metal lithium @ carbon composite material is 8-800 m²(ii)/g; preferably 60 to 400m²(ii)/g; more preferably 98 to 246m²(ii) in terms of/g. The effects are more excellent in the preferred ranges, for example, the stability and electrical properties of the composite material are more excellent.

Preferably, the shell thickness of the hollow carbon particles is 0.5-120 nm; preferably 3-60 nm; more preferably 14 to 35 nm. The effects are more excellent in the preferred ranges, for example, the stability and electrical properties of the composite material are more excellent.

Preferably, the filling chamber occupies 40% to 99% of the total volume; preferably 50 to 95 percent; more preferably 65 to 80%. The effects are more excellent in the preferred ranges, for example, the stability and electrical properties of the composite material are more excellent.

The content of the metal lithium is 40-98 wt.%; preferably 50 to 95 wt.%.

Preferably, the shell material of the hollow carbon particles is nitrogen-doped graphitized carbon. The uniform nitrogen doping is beneficial to regulating and controlling the transmission behavior of lithium ions and improving the uniform deposition of the metal lithium in the hollow carbon particles. The advantage is beneficial to the subsequent metal lithium @ carbon composite material obtained at high current density (2-10 mA/cm)²) And the circulation with ultra-stability and ultra-long service life is realized.

Preferably, the nitrogen content is 0.05-10 at.%; preferably 0.2 to 6 at.%; further preferably 0.6 to 4.1 at.%. The effects are more excellent in the preferred ranges, for example, the stability and electrical properties of the composite material are more excellent.

The invention provides a preparation method of a metal lithium @ carbon composite material, which comprises the following steps:

step (1): mixing the hollow carbon particles with an adhesive, coating the mixture on a metal foil, taking the metal foil as a working electrode and taking metal lithium as a counter electrode, and depositing the metal lithium in the hollow carbon particles by an electrodeposition method;

step (2): and (2) carrying out ultrasonic treatment on the metal foil subjected to electrodeposition in the step (1) in an organic solution, and then obtaining the metal lithium @ carbon composite material.

And mixing the hollow carbon particles with an adhesive, coating the mixture on a metal foil, taking the metal foil as a working electrode and metal lithium as a counter electrode, depositing the metal lithium in the hollow carbon particles by an electrodeposition method, then performing ultrasonic dispersion on the copper foil modified by the hollow carbon particles with the deposited lithium in an organic solution, and then drying collected filter residues to obtain the air-stable metal lithium @ carbon composite material.

The invention aims at solving the series problems of poor stability, serious interface side reaction and the like of the conventional 3D lithium metal anode. The metal lithium particles are coated by adopting nitrogen-doped graphitized carbon, so that the long-time stability in the air is realized, and the problem of side reaction at the interface is effectively solved.

The filling chamber of the hollow carbon particles is an independent chamber surrounded by graphitized carbon (shell layer).

Preferably, the hollow carbon particles have a specific surface area of 8 to 800m²(ii)/g; preferably 60 to 400m²(ii)/g; more preferably 98 to 246m²/g。

Preferably, the carbon wall thickness of the hollow carbon particles is 0.5-120 nm; preferably 3-60 nm; more preferably 14 to 35 nm.

Preferably, the size of the inner cavity (filling chamber) of the hollow carbon particle accounts for 40 to 99 percent of the total volume; preferably 50 to 95 percent; more preferably 65 to 80%.

Before the step (1), carrying out nitrogen doping treatment on the hollow carbon particles in advance: the hollow carbon particle carbon is obtained by roasting in a nitrogen-containing atmosphere.

The nitrogen source of the nitrogen-containing atmosphere is nitrogen and/or ammonia;

the content of the nitrogen-doped atmosphere nitrogen source is 5-95 vol%; preferably 15-75 vo 1%.

The roasting temperature is 600-1200 ℃; preferably 700 to 1100 ℃.

The roasting time is 0.4-20 h; preferably 0.6-15 h.

The nitrogen content of the hollow carbon particles after nitrogen doping is 0.05-10 at%; preferably 0.2 to 6 at.%; 0.6 to 4.1 at.%.

The adhesive is at least one of polyvinyl alcohol, polytetrafluoroethylene, sodium carboxymethylcellulose, polyvinylidene chloride and SBR rubber.

The metal foil is at least one of copper foil, titanium foil, nickel foil or alloy foil thereof.

The electrodeposition method is at least one of constant direct current electrodeposition, pulse electrodeposition, constant potential deposition and cyclic voltammetry electrodeposition; preferably galvanostatic deposition. The preferred constant direct current electrodeposition helps to further improve stability and improve electrical performance.

The organic solution is at least one of tetrahydrofuran, pyridine, pyrrole and corresponding alkyl derivatives thereof.

The electrolyte of the electrodeposition process is a material known to those skilled in the art.

The ultrasonic treatment is helpful for further improving the stability of the prepared metal lithium @ carbon composite material.

The invention provides an application of the metal lithium @ carbon composite material, which is used as a negative electrode active material for preparing a lithium metal negative electrode or a lithium ion battery negative electrode.

A carbon composite plane metal lithium anode comprises a plane metal current collector and an active layer compounded on the surface of the plane metal current collector; the active layer comprises the lithium metal @ carbon composite material.

A preferred carbon composite planar metallic lithium anode of the present invention comprises a planar metallic current collector and an active layer formed by direct compression of a metallic lithium @ carbon composite. The active layer comprises an adhesive and the metal lithium @ carbon composite material dispersed in the adhesive.

The metal lithium anode can effectively reduce interfacial reaction, and simultaneously provides more than actual specific capacity which is 4-10 times of that of the current commercial graphite cathode.

The invention also provides a preparation method of the carbon composite planar metal lithium anode, which comprises two implementation modes: mixing hollow carbon particles with an adhesive, coating the mixture on a metal foil, taking the metal foil as a working electrode and taking metal lithium as a counter electrode, and depositing the metal lithium in the hollow carbon particles by an electrodeposition method; and preparing the carbon composite planar lithium metal anode. The material prepared in the step (1) of the preparation method of the metal lithium @ carbon composite material is directly used as a carbon composite plane metal lithium anode.

(mode B) the lithium metal @ carbon composite material (e.g., the ultrasonically coated lithium metal @ carbon composite material prepared in step (2) of the preparation method of the lithium metal @ carbon composite material) is directly pressed on a metal planar current collector to prepare the carbon composite planar lithium metal anode.

The invention also provides an application of the carbon composite planar metal lithium anode, which is used as a negative electrode of a lithium ion battery;

preferably, it is used for preparing anodes of lithium oxygen batteries, lithium sulfur batteries, lithium selenium batteries, lithium tellurium batteries, lithium iodine batteries, lithium carbon dioxide batteries and lithium nitrogen batteries.

Advantageous effects

According to the air-stable lithium anode particle, the huge inner cavity of the hollow carbon particle provides a site for storing the metal lithium, and the carbon wall on the surface of the hollow carbon particle effectively prevents the metal lithium from being in direct contact with air and electrolyte, so that the occurrence of interface reaction is avoided. Such lithium anodes can eventually be stable in air for over 100 h.

The uniform nitrogen doping is beneficial to regulating and controlling the transmission behavior of lithium ions and improving the uniform deposition of the metal lithium in the hollow carbon particles.

Drawings

FIG. 1 is a morphology of hollow carbon particles of example 1: (a) SEM picture; (b) TEM image.

Fig. 2 is an SEM image of the copper foil modified with hollow carbon particles in example 1.

Fig. 3 is a TEM image of hollow carbon particle modification after lithium deposition in example 1.

Fig. 4 is an SEM image of lithium powder particles in comparative example 1.

Detailed Description

The following is a detailed description of the preferred embodiments of the invention and is not intended to limit the invention in any way, i.e., the invention is not intended to be limited to the embodiments described above, and modifications and alternative compounds that are conventional in the art are intended to be included within the scope of the invention as defined in the claims.