CN110600688A - Silene-copper-silylene composite material, preparation method, application and lithium ion battery - Google Patents

Silene-copper-silylene composite material, preparation method, application and lithium ion battery Download PDF

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CN110600688A
CN110600688A CN201910717452.4A CN201910717452A CN110600688A CN 110600688 A CN110600688 A CN 110600688A CN 201910717452 A CN201910717452 A CN 201910717452A CN 110600688 A CN110600688 A CN 110600688A
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copper
silylene
electrode
composite material
electrodeposition
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李冰
李国敏
沈奇欣
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East China University of Science and Technology
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/66—Electroplating: Baths therefor from melts
    • C25D3/665—Electroplating: Baths therefor from melts from ionic liquids
    • 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
    • H01M4/362—Composites
    • 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
    • H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/626—Metals
    • 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 discloses a silylene-copper-silylene composite material, a preparation method, application and a lithium ion battery. The preparation method of the silylene-copper-silylene composite material comprises the following steps: in the ionic liquid, a silicon source and a copper source are subjected to electrodeposition to obtain the copper-based electrolyte; wherein: the silicon source is SiCl4The copper in the copper source is divalent copper, the concentration of the copper source in the ionic liquid is 0.002-0.003 mol/L, and the potential of electrodeposition is-1.9 to-2.1V. In the invention, ionic liquid is used as a medium, and an electrodeposition method is adopted to prepare the silylene-copper-silylene composite material in one stepThe method has the advantages of simple and convenient process, low cost, recyclability and no pollution. The silicon alkene slice layer in the prepared silicon alkene-copper-silicon alkene composite material is highly dispersed, the conductivity of the electrode is good, and the electrochemical performance is excellent.

Description

Silene-copper-silylene composite material, preparation method, application and lithium ion battery
Technical Field
The invention relates to a silylene-copper-silylene composite material, a preparation method, application and a lithium ion battery.
Background
Unlike graphene, which is an allotrope of silicon and has a two-dimensional layered structure similar to graphene, silicon atoms in a silicon thin film are not completely on the same plane, but have a low-buckling structure of sp3 hybridization. Through calculation, the silicon alkene is predicted to have a mass-free Dirac Fermi, a quantum spin Hall effect and a superconducting property. These properties are of great significance for the design and application of silicon-based nanoelectronic and spintronic devices.
G.A. Tritsaris and the like calculate and research the interaction between lithium and silicon in independent single-layer and double-layer silylene model electrodes by adopting a first principle, determine a strong binding site of lithium ions, calculate an energy barrier for lithium ion diffusion, compare the energy barrier with silicon with other structures (such as nanowires), and evaluate the applicability of the silicon with a two-dimensional layered structure to lithium ion storage. (see G.A.Tritsaris, E.Kaxiras, S.Meng, E.G.Wang.Adsoration and Diffusion of lithium on layred Silicon for Li-Ion Storage [ J ]. Nano Letters 2013,13,2258.)
The silylene has enough space to adsorb and transfer lithium ions, so that the small volume change and the reversibility of structure change of the silylene in the charge-discharge process are ensured, and the silylene is expected to solve the problem of serious volume expansion of a silicon cathode; and generally, the theoretical specific capacity of the silicon alkene is far higher than that of the graphite cathode of the current lithium ion battery. The aforementioned characteristics theoretically guarantee the feasibility of the silylene as the negative electrode of the lithium ion battery, and show that the silylene is a promising negative electrode material of the lithium ion battery.
At present, the methods for preparing the silylene are less, and the reported methods are only a molecular beam epitaxial deposition method and a solid-phase reaction method.
The first work for the preparation of silylene, which was carried out in 2012 by depositing a monolayer of silylene on an Ag (111) substrate by means of molecular beam epitaxy[1-4]The literature then reports that Ir (111)[5]、ZrB2(001)[6]、ZrC(111)[7]And MoS2 [8]As substrates, high-quality single-layer or multilayer silylenes are obtained on these substrates.
(see [1] P.Vogt, P.D.Padova, C.Quaresmima, J.Avila, E.Frantzeskakis, M.C.Asenio, A.Resta, B.Eavel, G.L.Lay, Silicon: encapsulating Experimental evolution for graphene lithium Two-Dimensional Silicon [ J ] PHYSICAL REVIEW LETTERS,2012,108 (15)), 155501 155505.
[2]B.Feng,Z.Ding,S.Meng,Y.Yao,X.He,P.Cheng,L.Chen,K.Wu,Evidence of Silicene in Honeycomb Structures of Silicon on Ag(111)[J].Nano Letters,2012,12(7):3507-3511.
[3]D.Chiappe,C.Grazianetti,G.Tallarida,M.Fanciulli,A.Molle,Local Electronic Properties of Corrugated Silicene Phases[J].Advanced Materials,2012,24(37):5088-5093.
[4]H.Jamgotchian,Y.Colignon,N.Hamzaoui,B.Ealet,J.Y.Hoarau,B.Aufray,J.P.Biberian,J.Growth of silicene layers on Ag(111):unexpected effect of thesubstrate temperature[J].Journal of Physics Condensed Matter An Institute of Physics Journal,2012,24(17),172001-172007.
[5]L.Meng,Y.Wang,L.Zhang,S.Du,R.Wu,L.Li,Y.Zhang,G.Li,H.Zhou,W.Hofer,H.J.Gao,Buckled Silicene Formation on Ir(111)[J].Nano Letters,2013,13,685-690.
[6]A.Fleurence,R.Friedlein,T.Ozaki,H.Kawai,Y.Wang,Y.Yamada-Takamura,Experimental Evidence for Epitaxial Silicene on Diboride Thin Films[J].Physical Review Letters,2012,108(24),245501-245505.
[7]T.Aizawa,S.Suehara,S.Otani,J.Silicene on Zirconium Carbide(111)[J].Journal of Physical Chemistry C,2014,118(40):23049-23057.
[8]D.Chiappe,E.Scalise,E.Cinquanta,M.Houssa,A.Molle,Two-dimensional Si nanosheets with local hexagonal structure on a MoS(2)surface[J].Advanced Materials,2014,26(13):2096-2101.)
Du inserts oxygen atoms into the underlying layer of silylene, resulting in isolation of the silylene from the substrate Ag (111), resulting in a quasi-free-standing silylene layer. The uppermost layer of silylene exhibits a honeycomb lattice and has no mass dirac fermi due to less interaction with the substrate. (see Du Y, Zhuang J, Wang J, et al. Quasi-free epitaxialsilicene on Ag (111) by oxygen interaction [ J ]. Science Advances,2016,2(7): e1600067-e1600067.)
Noguchi et al prepared silylene materials using a solid state reaction method by subjecting a mixture of high purity Ca and Si in a certain ratio to a high temperature solid state reaction to form a layered ionic compound CaSi comprising alternately stacked calcium layers and silylene layers2The composition of which is Ca2+(Si2)2-Alternating layers of silylene and Ca [0001 ]]The crystal axes are stacked. (see e.noguchi, k.sugawara, r.yaokawa, t.hitosugi, h.nakano, t.takahashi.direct adherence of diamond Cone in Multilayer silicon interaction composite CaSi2[J].Advanced Materials,2015,27(5):856-860.)
Liu et al recently reported CaSi2As a precursor, the high-quality independent silicon alkene nano-flake is prepared by a liquid phase oxidation and stripping method. The new synthesis method enables CaSi2Of (Si)2n)2n-Moderate oxidation of the layer to neutral Si2nLayer, which preserves the complete structure of the silicon alkene, the obtained single layer or several layers of silicon alkene slices have better dispersibility and crystallinity, the silicon alkene nanometer slice is used as the cathode of the lithium ion battery, and the ratio of the silicon alkene nanometer slice to the silicon alkene is 0.1A g-1Under the multiplying power of (A), about 721mAh g is obtained-1After 1800 cycles, the capacity of the silylene nanosheet remains unchanged. (see J.Liu, Y.Yang, P.Lyu, P.Nachtigall, and Y.xu, Few-Layer silicon Nanosheets with Superior Lithium-Storage Properties, adv.Mater.2018,1800838.)
In the method for preparing the silicon alkene material, the molecular beam epitaxy technology requires higher experimental conditions and the product is generated slowly; the solid phase reaction method has complex flow and slow liquid phase oxidation and stripping speed.
Therefore, how to prepare a silicon alkene material with uniformly dispersed silicon alkene lamella and good electrochemical performance through a simple process becomes a technical problem to be solved in the field.
Disclosure of Invention
The invention aims to overcome the defects that a preparation method of a silylene material is complex and a prepared silylene sheet layer is easy to generate unevenness in the prior art, and provides a silylene-copper-silylene composite material, a preparation method, application and a lithium ion battery. The silicon alkene sheet layer in the silicon alkene-copper-silicon alkene composite material is highly dispersed, the conductivity of the electrode is good, and the electrochemical performance is excellent. The method takes the ionic liquid as a medium, adopts an electrodeposition method, prepares the silylene-copper-silylene composite material in one step, and has simple and convenient process, low cost, recyclability and no pollution; in addition, the product prepared by the electrodeposition method can also be directly used as the cathode of the lithium ion battery, and the preparation process and the coating process of slurry required by the traditional lithium ion battery cathode material are avoided. The silicon alkene-copper-silicon alkene composite material obtained by the invention can be used in nano electronic devices and spin electronic devices, and has a wide application range.
The invention provides a preparation method of a silylene-copper-silylene composite material, which comprises the following steps: in the ionic liquid, a silicon source and a copper source are subjected to electrodeposition to obtain the copper-based electrolyte; wherein:
the silicon source is SiCl4The copper in the copper source is bivalent copper;
the concentration of the copper source in the ionic liquid is 0.002-0.003 mol/L;
the potential of the electrodeposition is-1.9 to-2.1V.
In the present invention, the ionic liquid may be an ionic liquid conventional in the art, for example, [ BMP ]]Tf2N。
According to the invention, the ionic liquid can be repeatedly used.
In the present invention, the concentration of the silicon source may be a concentration conventional in the art, and is generally a supersaturated state in the ionic liquid. When the ionic liquid is [ BMP ]]Tf2In the case of N, the concentration of the silicon source is preferably 0.5 to 1mol/L, for example, 1 mol/L.
In the present invention, the copper source may be Cu-containing as is conventional in the art2+Of (2), e.g. CuxRy。
WhereinSaid CuxRyX and y in (1) can be according to Cu2+The number of ligands R that can be bound is a positive integer.
Wherein R may be Cu, which is conventional in the art2+The ligand group is preferably TfO (trifluoromethanesulfonic acid group).
Wherein the copper source is preferably Cu (TfO)2。
In the present invention, the concentration of the copper source is preferably 0.002 mol/L.
When the ionic liquid is [ BMP ]]Tf2In the case of N, the concentration of the copper source is preferably 0.002 mol/L.
In the present invention, preferably, the silicon source and the ionic liquid are first mixed, and then mixed with the copper source for the second time. Wherein the first mixing and the second mixing can be performed in a screw bottle.
In the present invention, the electrodeposition is preferably constant potential electrodeposition.
In the present invention, the electrodeposition can be carried out using an electrolytic system conventional in the art, for example, in a three-electrode system.
The three-electrode system may be a three-electrode system conventional in the art, and generally includes a working electrode, a reference electrode, and a counter electrode.
The working electrode may be a working electrode conventional in the art, such as copper, nickel, silver, gold, platinum or titanium, preferably copper.
The reference electrode may be a reference electrode conventional in the art, for example, a platinum wire is used as an electrode material, and the reference electrode may be formed by immersing the whole or part of the reference electrode in the ionic liquid.
Generally, the reference electrode is configured as a glass tube, wherein an end of the glass tube, which is away from the electrolyte, is open, and an end, which is in contact with the electrolyte, is filled with porous ceramic, and the inside of the glass tube is in communication with the electrolyte through the porous ceramic.
The counter electrode may be a counter electrode conventional in the art, such as a graphite sheet.
The distance between the working electrode and the reference electrode can be 1-2 mm.
The distance between the working electrode and the counter electrode can be 10-40 mm.
When the silylene-copper-silylene composite material is used for a negative electrode of a lithium ion battery, preferably, a copper sheet is used as a working electrode, a graphite sheet is used as a counter electrode, and the composite material prepared by the system has high stability.
When a copper sheet is used as a working electrode and a graphite sheet is used as a counter electrode, the silicon alkene-copper-silicon alkene composite material is attached to the copper sheet and can be directly used as a lithium ion battery cathode to be assembled inside the battery after electrodeposition.
In the present invention, the potential of the electrodeposition is preferably-1.9 to-2.0V, more preferably-1.9V or-2.0V.
In the present invention, the electrodeposited potential is generally referred to as the potential of the working electrode relative to the reference electrode, for example, in a three-electrode system, the potential may be the insertion of a copper electrode relative to a platinum wire into a container containing [ BMP ]]Tf2The potential of the reference electrode formed in the N-ion liquid and the glass tube with porous ceramic below.
In the invention, when the electric potential of the electrodeposition is-1.9V, the prepared silicon alkene-copper-silicon alkene composite material has excellent appearance, has a graphene-like lamellar structure, and has a relatively stable electrodeposition process. Preferably, the potential of the electrodeposition is-1.9V vs Pt/[ BMP]Tf2N。
In the invention, the temperature of the electrodeposition is preferably 15-40 ℃, for example 20-30 ℃, and further for example 20 ℃ or 30 ℃.
In the invention, the time of the electrodeposition is preferably 3600-7200 seconds, such as 3600 seconds.
In the present invention, the electrode in the electrodeposition method may be pretreated in a conventional manner in the art. The pretreatment can be polishing treatment and cleaning treatment in sequence.
Preferably, the grinding treatment is grinding and polishing to a mirror image by using coarse-to-fine metallographic abrasive paper.
Wherein, preferably, the cleaning treatment is a first water washing, an acid washing and a second water washing in sequence.
The first water washing may be ultrasonic washing with deionized water, for example, ultrasonic washing with deionized water for 10 min.
The conditions of the acid washing may be selected according to the properties of the material, for example, the platinum wire electrode is washed with nitric acid; pickling the copper wire electrode with sulfuric acid; the graphite electrode was not acid washed. The nitric acid washing concentration can be 1-2 mol/L, such as 2 mol/L. The sulfuric acid pickling concentration can be 1-2 mol/L, such as 2 mol/L.
The second washing is deionized water washing. After washing, vacuum drying or air drying can be adopted.
Preferably, the water washing is dried and then washed with acetone, for example, by soaking in acetone for 10 min.
In the present invention, after the electrodeposition, the electrode on which the silylene-copper-silylene composite material is deposited may be post-treated by a conventional method in the art. The post-treatment may be an acetone wash.
In the present invention, the silylene-copper-silylene composite is generally attached to a base material (e.g., a working electrode) after the electrodeposition. The silylene-copper-silylene composite material and the substrate material can be separated by ultrasonic treatment in a solvent. The solvent may be acetone and/or absolute ethanol.
In the present invention, preferably, the preparation of the silylene-copper-silylene composite is carried out under the condition that the content of oxygen and water is less than 1ppm, for example, in a glove box.
The invention also provides a silylene-copper-silylene composite material prepared by the method.
The invention also provides a silylene-copper-silylene composite material which comprises a stacked structure of a sheet material and a porous material, wherein the sheet material is a silylene sheet layer, and the porous material is copper; the thickness of the silylene-copper-silylene composite material is 15-20 mu m; the thickness of the silicon sheet layer is 5-20 nm, and the length of the silicon sheet layer is 0.7-1.2 mu m.
In the present invention, preferably, the silylene-copper-silylene composite material is as shown in fig. 2 or fig. 3.
In the invention, the silylene-copper-silylene composite material can still maintain the capacity of 1319.3mAh/g after 750 cycles at the multiplying power of 1C (the discharge current density is 4A/g). The silicon alkene-copper-silicon alkene composite material is high in capacity, good in cycle performance and excellent in rate capability.
The silylene-copper-silylene composite material obtained by the invention can be directly used for assembling a battery after being cleaned. The assembled battery may be a button cell battery, a pouch cell battery, or the like. The mounting button cell can be a half cell or a full cell.
The invention also provides an application of the silylene-copper-silylene composite material as a cathode material in an electronic device.
Wherein the electronic device may be one or more of a nanoelectronic device, a spintronic device, and a battery (e.g., a lithium ion battery).
The invention also provides a lithium ion battery which adopts the silicon alkene-copper-silicon alkene composite material as a negative electrode.
The battery may be an assembled battery. The assembled battery can be a button cell battery or a pouch cell battery. The button cell can be a half cell or a full cell.
When the silylene-copper-silylene composite is applied to a half cell, a lithium sheet is generally used as a counter electrode. The electrolyte used may be 1M LiPF6the/EC-DMC-EMC (ethylene carbonate-methylethyl carbonate-dimethyl carbonate) (volume ratio 1:1:1), the separator used may be Celgard 2400.
The assembled battery can adopt a charge-discharge battery tester to detect the performance of the battery, and the test method is constant-current charge-discharge. The characterized content includes: capacity, cycle performance, rate performance, coulombic efficiency. Where all capacities are calculated based on the mass of silicon.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The positive progress effects of the invention are as follows:
(1) the ionic liquid solution adopted by the invention is CuxRy-SiCl4-[BMP]Tf2N (e.g. Cu (TFO))2-SiCl4-[BMP]Tf2N), the system is not required to be heated, all the ionic liquid is liquid at room temperature, the ionic liquid in the system can be recycled, the environmental protection is realized, the pollution is avoided, the operation can be carried out at room temperature, the energy consumption is low, the cost is low, and the large-scale preparation is favorably realized.
(2) The method has simple process, realizes one-step method to obtain the silicon alkene-copper-silicon alkene composite material, and the prepared composite material has a sheet and hole stacking structure and can form a sheet layer structure (sheet structure of silicon alkene) similar to graphene.
(3) The prepared silylene-copper-silylene composite material has high capacity, good cycling performance (for example, under the condition of 4A/g of discharge current density, 1319.3mAh/g of capacity can be still maintained after 750 cycles), and excellent rate performance (for example, 748.8mAh/g of capacity is maintained under 42A/g of current density).
Drawings
FIG. 1 shows Cu (TFO)2-SiCl4-[BMP]Tf2Cyclic voltammetry curves in N ionic liquids.
FIG. 2 is a SEM image of the composite of Si-Fe-Si prepared in example 1, wherein: FIGS. 2a, 2b and 2c are SEM images of the product obtained in example 1, and FIG. 2d is a backscattered image of FIG. 2a, in which different gray scales represent different elements and the composition of the strip structure and the porous plane is different.
FIG. 3 is a transmission electron micrograph (TEM image) of the silylene-copper-silylene composite obtained in example 1, wherein: fig. 3a, 3b, 3c and 3d are taken at different positions, respectively, and the arrow in fig. 3a indicates the lamellar structure.
FIG. 4 shows the cycle characteristics of the silylene-copper-silylene composite material prepared in example 1, with a charge/discharge current density of 4A/g.
FIG. 5 is a charge-discharge curve of the silylene-copper-silylene composite material prepared in example 1, wherein the charge-discharge current density is 4A/g.
FIG. 6 shows the rate capability of the silylene-copper-silylene composite material prepared in example 1, wherein the charge/discharge rates are 2A/g, 4A/g, 8A/g, 21A/g, 42A/g and 4A/g, respectively.
FIG. 7 is a SEM image of the composite material of example 3, wherein FIGS. 7a and 7b show micrographs at different magnifications.
FIG. 8 is a scanning electron microscope photograph of the silylene-copper-silylene composite material prepared in example 4.
FIG. 9 shows the cycle characteristics of the silylene-copper-silylene composite material obtained in comparative example 1, with a charge/discharge current density of 2A/g.
FIG. 10 is a scanning electron microscope image of a silylene-copper-silylene composite obtained in comparative example 2, in which FIG. 10a and FIG. 10b show micrographs at different magnifications, respectively.
Fig. 11 is a scanning electron microscope photograph of the silylene-copper-silylene composite material prepared in comparative example 3.
FIG. 12 shows the cycle characteristics of the silylene-copper-silylene composite material obtained in comparative example 3, and the charge/discharge current density thereof was 4A/g.
FIG. 13 shows the cycle characteristics of the silylene-copper-silylene composite obtained in comparative example 4, with a charge/discharge current density of 4A/g.
FIG. 14 shows the cycle characteristics of the silylene-copper-silylene composite material obtained in comparative example 6, with a charge/discharge current density of 4A/g.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
In the following examples and comparative examples:
Cu(TFO)2purchased from Alfa Aesar;
SiCl4purchased from Alfa Aesar;
[BMP]Tf2n was purchased from Shanghai Chengjie chemical Co.
In the following examples and comparative examples:
Cu(TFO)2-SiCl4-[BMP]Tf2the test method of the cyclic voltammetry curve in the N ionic liquid is as follows:
(1) preparing an ionic liquid: preparation of (0.002 mol/L) Cu (TFO)2-1mol/L SiCl4Of [ BMP ]]Tf2N solution of 1mol/L SiCl4Of [ BMP ]]Tf2Solution of N and [ BMP ]]Tf2And (4) N solution.
(2) Electrode treatment: firstly, the platinum electrode is ground and polished to a mirror image by adopting coarse-to-fine metallographic abrasive paper, and then the platinum electrode is ultrasonically cleaned by deionized water. Then, the platinum electrode was pickled with 2mol/L nitric acid, rinsed with deionized water, and then dried in a vacuum oven. Finally, all electrodes were cleaned with acetone and then air dried.
(3) Preparation of an electrolytic cell: the working electrode is a platinum wire; the counter electrode is a graphite sheet; the reference electrode is a glass tube device, and [ BMP ] is contained in the glass tube]Tf2N ionic liquid, the upper end opening is inserted into a platinum wire to be added into the ionic liquid, the lower end is provided with porous ceramics, the reference electrode is communicated with the electrolytic cell through the porous ceramics, and the reference electrode is Pt/[ BMP ]]Tf2N, abbreviated as Pt.
Cyclic voltammetry curves of the solutions are respectively detected, and are shown in figure 1. As can be seen from FIG. 1, the solution (i) shows reduction peaks at-1.5V and-2.0V, in which Cu appears at-1.5V2+Reduction to Cu+Followed by Cu at-2.0V+A reduction peak to Cu, and a reduction current of silicon after-2.2V. It can be seen that Cu (TFO) is added2In the case of a copper source, the reduction of Cu is carried out in two steps, first from Cu2+Reduction to Cu+Then from Cu again+Reducing the alloy into Cu.
Example 1
(1) Preparing an ionic liquid: preparation of 0.002mol/L Cu (TFO)2-1mol/L SiCl4Of [ BMP ]]Tf2And fully stirring the solution N until the solution is uniformly dispersed.
(2) Electrode treatment: firstly, grinding and polishing the electrode to a mirror image by using coarse-to-fine metallographic abrasive paper, and then ultrasonically cleaning by using deionized water. Then, the platinum electrode is pickled by 2mol/L nitric acid, the Cu electrode is pickled by 2mol/L sulfuric acid, deionized water is adopted for washing, and then drying is carried out in a vacuum oven. Finally, all electrodes were cleaned with acetone and then air dried.
(3) Preparation of an electrolytic cell: the electrolytic cell used in the experiment was a three-electrode system. Wherein, the three electrodes refer to a working electrode, a reference electrode and a counter electrode. The distance between the electrodes is controlled to be unchanged in each experiment (the distance between the working electrode and the reference electrode is 1-2 mm, and the distance between the working electrode and the counter electrode is 10-40 mm). The working electrode is a copper sheet; the reference electrode is a glass tube device, and [ BMP ] is contained in the glass tube]Tf2N ionic liquid, the upper end opening is inserted into a platinum wire to be added into the ionic liquid, the lower end is provided with porous ceramics, the reference electrode is communicated with the electrolytic cell through the porous ceramics, and the reference electrode is Pt/[ BMP ]]Tf2N, abbreviated as Pt; the counter electrode is a graphite sheet.
(4) Electro-deposition: in Cu (TFO)2-SiCl4-[BMP]Tf2Preparing a copper-silicon composite material by electrodeposition in an N ionic liquid system, wherein constant potential electrodeposition is adopted, and the potential is as follows: -1.9V vs. pt; temperature: 20 ℃; time: 3600 s.
(5) Electrode cleaning: after electrodeposition, the electrode is taken out, washed three times by acetone and dried to be directly used as the cathode of the lithium ion battery.
(6) Installing a battery: and cleaning the obtained silylene-copper-silylene composite material by electrodeposition, and directly assembling the battery. The assembled battery may be a button cell battery, a pouch cell battery, or the like. The mounting button cell can be a half cell or a full cell. When a half cell is used, a metallic lithium plate is used as a counter electrode.
(7) And (3) testing the battery performance: the equipment for testing the battery performance is a charge-discharge battery tester, the testing method is constant current charge-discharge, and the characterization content is as follows: capacity, cycle performance, coulombic efficiency, rate capability.
Fig. 2 is a structural diagram of the silylene-copper-silylene composite material obtained in this example, and as can be seen from fig. 2, the silylene-copper-silylene composite material has a stacked structure of sheets and holes, and a strip structure is formed by winding a rectangular sheet on a porous plane. As can be seen from fig. 2a, the silylene-copper-silylene composite material is in a state of two different structures being stacked, the upper part is a strip structure composed of sheets, the lower part is a network structure of macropores, and the two different elements are obtained by the back scattering diagram of fig. 2d, the upper part is Si, and the lower part is Cu; as can be seen from fig. 2c, the lower layer of the network structure also has a sheet structure, and thus a structure in which the layers of the silylene and the copper layer are stacked in the silylene-copper-silylene composite can be seen. In addition, as can be clearly seen from FIG. 2b and FIG. 2c, the thickness of the silicon graphene layer is 5-20 nm, the length is about 0.7-1.2 μm, and the pore diameter of the porous plane is about 200-400 nm.
Fig. 3 is a TEM image of the deposited silylene-copper-silylene composite material obtained in this example, and although the stacked structure of Si and Cu was destroyed due to the ultrasonic treatment, some pore structures can be seen in fig. 3, similar to those of Cu seen in fig. 2. Also, a relatively thin sheet structure (as indicated by the arrows in fig. 3 a) can be observed in the figure, similar to the thin sheet structure of graphene, which is consistent with the striped Si morphology observed in fig. 2.
The silylene-copper-silylene composite material obtained in the embodiment has good performance as a lithium ion battery cathode, and can still have the capacity of 1319.3mAh/g after being cycled for 750 times under 4A/g calculated by the mass of silicon element, and the coulombic efficiency is 97% (as shown in FIG. 4 and Table 1); the platform has relatively good reversibility of lithium extraction and insertion (as shown in figure 5 and table 2); the multiplying power performance is good, and the capacitor has the capacity of 748.8mAh/g under the current density of 42A/g (shown in figure 6 and table 3).
TABLE 1
Current density of charge and discharge Cycle performance Discharge capacity
4A/g And (4) circulating for 750 times: discharge capacity 1319.3mAh/g, coulombic efficiency 97% 1319.3mAh/g
TABLE 2
Number of cycles 1st 10th 100th 200th 400th
Discharge capacity mAh/g 1592.2 1635.2 1600.1 1593.3 1476.6
TABLE 3
Current density of charge and discharge 2A/g 4A/g 8A/g 21A/g 42A/g 4A/g
Discharge capacity mAh/g 1992.6 1767.5 1399.6 1097.2 773.4 1717.2
Example 2
(1) Preparation of ionic liquid: 1mol/L SiCl is prepared4Of [ BMP ]]Tf2N solution, 0.002mol/L Cu (TFO) was added2Fully stirring to obtain a uniformly dispersed yellow solution.
(2) Electrode treatment: firstly, grinding and polishing the electrode by using coarse-to-fine metallographic abrasive paper to obtain a mirror image, and then ultrasonically cleaning the mirror image by using deionized water. Then, the platinum electrode is washed by 2mol/L nitric acid, the Cu electrode is washed by 2mol/L sulfuric acid, and the electrode is dried in a vacuum oven after being washed by deionized water. Finally, all electrodes were air-dried after being washed with acetone.
(3) Preparation of an electrolytic cell: the electrolytic cell used in the experiment was a three-electrode system. Wherein, the three electrodes are working electrodes and reference electrodesThe electrode and the counter electrode are controlled to be consistent in distance in each experiment. The working electrode is a copper sheet; the reference electrode is a glass tube device, and [ BMP ] is contained in the glass tube]Tf2N ionic liquid, the upper end opening is inserted into a platinum wire to be added into the ionic liquid, the lower end is provided with porous ceramics, the reference electrode is communicated with the electrolytic cell through the porous ceramics, and the reference electrode is Pt/[ BMP ]]Tf2N, abbreviated as Pt; the counter electrode is a graphite sheet.
(4) Electro-deposition: in Cu (TFO)2-SiCl4-[BMP]Tf2Preparing the copper-silicon alkene composite material by electrodeposition in an N system, wherein constant potential electrodeposition is adopted, and the potential is as follows: -1.9V vs. pt; temperature: 30 ℃, time: 3600 s.
(5) Electrode cleaning: after electrodeposition, the electrode was taken out and washed three times with acetone and dried.
The shape of the silylene-copper-silylene composite material obtained in the embodiment is similar to that of the silylene-copper-silylene composite material obtained in the embodiment 1, and the silylene-copper-silylene composite material is of a sheet-shaped and hole-shaped stacked structure.
The performance of the silylene-copper-silylene composite material obtained in the embodiment as the negative electrode of the lithium ion battery is equivalent to the performance of the silylene-copper-silylene composite material as the negative electrode of the lithium ion battery in the embodiment 1.
Example 3
(1) Preparation of ionic liquid: 1mol/L SiCl is prepared4Of [ BMP ]]Tf2N solution, 0.002mol/L Cu (TFO) was added2Fully stirring to obtain a uniformly dispersed yellow solution.
(2) Electrode treatment: firstly, grinding and polishing the electrode by using coarse-to-fine metallographic abrasive paper to obtain a mirror image, and then ultrasonically cleaning the mirror image by using deionized water. Then, the platinum electrode is washed by 2mol/L nitric acid, the Cu electrode is washed by 2mol/L sulfuric acid, and the electrode is dried in a vacuum oven after being washed by deionized water. Finally, all electrodes were air-dried after being washed with acetone.
(3) Preparation of an electrolytic cell: the electrolytic cell used in the experiment was a three-electrode system. The three electrodes are a working electrode, a reference electrode and a counter electrode, and the distance between the electrodes is controlled to be consistent in each experiment. The working electrode is a copper sheet; the reference electrode is a glassA glass tube device, the glass tube is filled with [ BMP ]]Tf2N ionic liquid, the upper end opening is inserted into a platinum wire to be added into the ionic liquid, the lower end is provided with porous ceramics, the reference electrode is communicated with the electrolytic cell through the porous ceramics, and the reference electrode is Pt/[ BMP ]]Tf2N, abbreviated as Pt; the counter electrode is a graphite sheet.
(4) Electro-deposition: in Cu (TFO)2-SiCl4-[BMP]Tf2Preparing a copper-silicon cathode material by electrodeposition in an N system, wherein constant potential electrodeposition is adopted, and the potential is as follows: -2.0V vs. pt; temperature: 20 ℃, time: 3600 s.
(5) Electrode cleaning: after electrodeposition, the electrode was taken out and washed three times with acetone and dried.
The silylene-copper-silylene composite material obtained in example 3 fused with each other to form a uniform film, and as shown in fig. 7, a lamellar structure of silylene was observed, but a larger particle was doped therein.
The cycling performance of the cells made of the silylene-copper-silylene composites obtained in example 3 and example 1 are compared as shown in table 4 (charge-discharge current density of 4A/g), and the cell capacity made of the material in example 3 is lower than that of the cell capacity made of the material in example 1.
TABLE 4
Example 4
(1) Preparation of ionic liquid: 1mol/L SiCl is prepared4Of [ BMP ]]Tf2N solution, 0.002mol/L Cu (TFO) was added2Fully stirring to obtain a uniformly dispersed yellow solution.
(2) Electrode treatment: firstly, grinding and polishing the electrode by using coarse-to-fine metallographic abrasive paper to obtain a mirror image, and then ultrasonically cleaning the mirror image by using deionized water. Then, the platinum electrode is washed by 2mol/L nitric acid, the Cu electrode is washed by 2mol/L sulfuric acid, and the electrode is dried in a vacuum oven after being washed by deionized water. Finally, all electrodes were air-dried after being washed with acetone.
(3) Preparation of an electrolytic cell: the electrolytic cell used in the experiment was a three-electrode system. WhereinThe three electrodes are a working electrode, a reference electrode and a counter electrode, and the distance between the electrodes is controlled to be consistent in each experiment. The working electrode is a copper sheet; the reference electrode is a glass tube device, and [ BMP ] is contained in the glass tube]Tf2N ionic liquid, the upper end opening is inserted into a platinum wire to be added into the ionic liquid, the lower end is provided with porous ceramics, the reference electrode is communicated with the electrolytic cell through the porous ceramics, and the reference electrode is Pt/[ BMP ]]Tf2N, abbreviated as Pt; the counter electrode is a graphite sheet.
(4) Electro-deposition: in Cu (TFO)2-SiCl4-[BMP]Tf2Preparing the copper-silicon alkene composite material by electrodeposition in an N system, wherein constant potential electrodeposition is adopted, and the potential is as follows: -2.0V vs. pt; temperature: 30 ℃, time: 3600 s.
(5) Electrode cleaning: after electrodeposition, the electrode was taken out and washed three times with acetone and dried.
Similar to the morphology of example 3, the resulting copper-silicon composite fused with each other to form a uniform film, as shown in fig. 8, having a sheet-like structure of silylene, but with larger particles doped therein.
Comparative example 1
(1) Preparation of ionic liquid: 1mol/L SiCl is prepared4Of [ BMP ]]Tf2And (4) fully stirring the solution N until the solution is transparent and uniform.
(2) Electrode treatment: firstly, grinding and polishing the electrode to a mirror image by using coarse-to-fine metallographic abrasive paper, and then ultrasonically cleaning by using deionized water. Then, the platinum electrode is pickled by 2mol/L nitric acid, the Cu electrode is pickled by 2mol/L sulfuric acid, deionized water is adopted for washing, and then drying is carried out in a vacuum oven. Finally, all electrodes were cleaned with acetone and then air dried.
(3) Preparation of an electrolytic cell: the electrolytic cell used in the experiment was a three-electrode system. Wherein, the three electrodes refer to a working electrode, a reference electrode and a counter electrode. The distance between the electrodes is controlled to be consistent in each experiment. The working electrode is a copper sheet; the reference electrode is a glass tube device, and [ BMP ] is contained in the glass tube]Tf2N ionic liquid, platinum wire inserted into the ionic liquid at the upper end opening, porous ceramic at the lower end, and reference electrode passing through the porous ceramicThe ceramic is communicated with the electrolytic cell, and the reference electrode is Pt/[ BMP]Tf2N, abbreviated as Pt; the counter electrode is a graphite sheet. The copper sheet is used as the working electrode because the copper sheet is a commonly used lithium ion battery negative electrode current collector, the platinum wire is used as the reference electrode because the platinum wire is stable in the ionic liquid, and the graphite sheet is used as the counter electrode because the graphite sheet has higher stability under the system.
(4) Electro-deposition: in SiCl4-[BMP]Tf2Preparing a copper-silicon composite material by electrodeposition in an N ionic liquid system, wherein constant potential electrodeposition is adopted, and the potential is as follows: -2.0V vs. pt; temperature: 25 ℃; time: 3600 s.
(5) Electrode cleaning: after electrodeposition, the electrode is taken out, washed three times by acetone and dried to be directly used as the electrode of the lithium ion battery.
The silica material obtained in comparative example 1 was granular and no silylene was formed. Fig. 9 is a cycle performance test chart of the copper-silicon composite material obtained in comparative example 1 as the negative electrode of the lithium ion battery, and it can be known from fig. 9 that the obtained silicon material as the negative electrode of the lithium ion battery has poorer cycle performance than the example, and the specific capacity of the battery is 604.7mAh/g after the silicon material is cycled for 100 times at a current density of 2A/g calculated by the mass of the silicon.
Comparative example 2
(1) Preparation of ionic liquid: 1mol/L SiCl is prepared4Of [ BMP ]]Tf2Adding 0.006mol/L CuCl into the N solution, fully stirring, and ultrasonically dispersing for 1 hour until the solution is uniformly dispersed.
(2) Electrode treatment: firstly, grinding and polishing the electrode by using coarse-to-fine metallographic abrasive paper to obtain a mirror image, and then ultrasonically cleaning the mirror image by using deionized water. Then, the platinum electrode is washed by 2mol/L nitric acid, the Cu electrode is washed by 2mol/L sulfuric acid, and the electrode is dried in a vacuum oven after being washed by deionized water. Finally, all electrodes were air-dried after being washed with acetone.
(3) Preparation of an electrolytic cell: the electrolytic cell used in the experiment was a three-electrode system. The three electrodes are a working electrode, a reference electrode and a counter electrode, and the distance between the electrodes is controlled to be consistent in each experiment. The working electrode is a copper sheet; the reference electrode is a glass tube device,the glass tube is filled with [ BMP]Tf2N ionic liquid, the upper end opening is inserted into a platinum wire to be added into the ionic liquid, the lower end is provided with porous ceramics, the reference electrode is communicated with the electrolytic cell through the porous ceramics, and the reference electrode is Pt/[ BMP ]]Tf2N, abbreviated as Pt; the counter electrode is a graphite sheet. The copper sheet is used as the working electrode because the copper sheet is a commonly used lithium ion battery negative electrode current collector, the platinum wire is used as the reference electrode because the platinum wire is stable in the ionic liquid, and the graphite sheet is used as the counter electrode because the graphite sheet has higher stability under the system.
(4) Electro-deposition: in CuCl-SiCl4-[BMP]Tf2Preparing a copper-silicon composite material by electrodeposition in an N system, wherein constant potential electrodeposition is adopted, and the potential is as follows: -1.9V vs. pt; temperature: 25 ℃, time: 3600 s.
(5) Electrode cleaning: after electrodeposition, the electrode is taken out and washed with acetonitrile for three times, and the electrode can be directly used as an electrode of a lithium ion battery after drying, namely the lithium ion battery copper-silicon composite material.
(6) And (4) installing the battery, and directly using the copper-silicon composite material obtained by electrodeposition for assembling the battery after cleaning. The assembled battery may be a button cell battery, a pouch cell battery, or the like. The mounting button cell can be a half cell or a full cell. When a half cell is used, a metallic lithium plate is used as a counter electrode.
(7) Testing the battery performance, wherein the equipment for testing the battery performance is a charging and discharging battery tester, the testing method is constant current charging and discharging, and the characterization content is as follows: capacity, cycle performance, coulombic efficiency, rate capability.
Comparative example 2 the copper source used was different from that of example 1, and fig. 10 is an SEM image of the material obtained in comparative example 2, and it can be seen from the figure that the material was granular and was not formed into a flake shape, which is greatly different from the morphology of examples 1 and 2.
Comparative example 3
(1) Preparation of ionic liquid: 1mol/L SiCl is prepared4Of [ BMP ]]Tf2And adding 0.006mol/LCuTfO into the N solution, fully stirring, and ultrasonically dispersing for 1 hour until the solution is uniformly dispersed.
(2) Electrode treatment: firstly, grinding and polishing the electrode to a mirror image by using coarse-to-fine metallographic abrasive paper, and then ultrasonically cleaning by using deionized water. Then, the platinum electrode was pickled with 2M nitric acid, the Cu electrode was pickled with 2M sulfuric acid, and rinsed with deionized water, followed by drying in a vacuum oven. Finally, all electrodes were cleaned with acetone and then air dried.
(3) The preparation of the electrolytic cell, the electrolytic cell used for the experiment is a three-electrode system. Wherein, the three electrodes refer to a working electrode, a reference electrode and a counter electrode. The distance between the electrodes is controlled to be consistent in each experiment. The working electrode is a copper sheet; the reference electrode is a glass tube device, and [ BMP ] is contained in the glass tube]Tf2N ionic liquid, the upper end opening is inserted into a platinum wire to be added into the ionic liquid, the lower end is provided with porous ceramics, the reference electrode is communicated with the electrolytic cell through the porous ceramics, and the reference electrode is Pt/[ BMP ]]Tf2N, abbreviated as Pt; the counter electrode is a graphite sheet. The copper sheet is used as the working electrode because the copper sheet is a commonly used lithium ion battery negative electrode current collector, the platinum wire is used as the reference electrode because the platinum wire is stable in the ionic liquid, and the graphite sheet is used as the counter electrode because the graphite sheet has higher stability under the system.
(4) Electro-deposition: in CuTfO-SiCl4-[BMP]Tf2Preparing a copper-silicon composite material by electrodeposition in an N ionic liquid system, wherein constant potential electrodeposition is adopted, and the potential is as follows: -1.9V vs. pt; temperature: 25 ℃; time: 3600 s.
(5) Electrode cleaning: and after electrodeposition, taking out the electrode, washing the electrode for three times by using acetonitrile, and drying the electrode to be directly used as an electrode of a lithium ion battery, namely the lithium ion battery copper-silicon composite material.
(6) Installing a battery: and (4) directly assembling the battery after cleaning the copper-silicon composite material obtained by electrodeposition. The assembled battery may be a button cell battery, a pouch cell battery, or the like. The mounting button cell can be a half cell or a full cell. When a half cell is used, a metallic lithium plate is used as a counter electrode.
(7) And (3) testing the battery performance: the equipment for testing the battery performance is a charge-discharge battery tester, the testing method is constant current charge-discharge, and the characterization content is as follows: capacity, cycle performance, coulombic efficiency, rate capability.
Comparative example 3 the copper source used was different from that of example 1.
Fig. 11 is an SEM image of the copper-silicon composite material obtained in comparative example 3, and it can be seen from the SEM image that the surface of the composite material is in a relatively smooth state with flat particles, and no lamellar structure is formed.
FIG. 12 is a graph showing the cycle performance of the copper-silicon composite material obtained in comparative example 3 as a negative electrode of a lithium ion battery. Through cycle testing, the charge and discharge capacity of the battery prepared from the composite material of the comparative example 3 is always in a decaying state, the capacity is 1150mAh/g after the battery is cycled for 750 circles at 4A/g, and the cycle performance is relatively poor compared with that of the battery prepared from the composite material of the example 1.
Comparative example 4
The concentration of the copper source in the ionic liquid was 0.004mol/L, as in example 1.
FIG. 13 is a graph showing the cycle performance of the copper-silicon composite obtained in comparative example 4 as a negative electrode of a lithium ion battery. Through a cycle test, the specific capacity of the material tends to be stable after 50 circles under the rate of 4A/g, no obvious attenuation is caused, but the specific capacity is lower as a whole and is less than 600 mAh/g.
Comparative example 5
The concentration of the copper source in the ionic liquid was 0.001mol/L, as in example 1.
The copper-silicon composite material obtained in the comparative example 5 is used as a negative electrode of a lithium ion battery, and cycle tests show that the initial capacity is 836.6mAh/g, the initial coulombic efficiency is 94.4 percent, the capacity after 800 cycles is 397mAh/g, and the coulombic efficiency is 97.5 percent at the rate of 4A/g. The specific capacity was low and the cycling performance was poor compared to example 1.
Comparative example 6
The potential for electrodeposition was-2.2V, as in example 1.
FIG. 14 is a graph showing the cycle performance of the copper-silicon composite obtained in comparative example 6 as a negative electrode of a lithium ion battery. Through cycle testing, the initial capacity is 1020.4mAh/g, the initial coulombic efficiency is 86 percent, the capacity after 800 cycles is 1038.2mAh/g, and the coulombic efficiency is 95 percent under the 4A/g multiplying power. The cycle performance was relatively poor compared to example 1.
Comparative example 7
The potential for electrodeposition was-1.8V, as in example 1.
The copper-silicon composite material obtained in the comparative example 7 is used as a negative electrode of a lithium ion battery, and cycle tests show that the initial capacity is 1153.5mAh/g, the initial coulombic efficiency is 111%, the capacity after 800 cycles is 656.3mAh/g, and the coulombic efficiency is 98.6% under the multiplying power of 4A/g. The specific capacity was low and the cycling performance was poor compared to example 1.
Comparative example 8
Refer to the method described in example 4 of conventional patent CN 108232149 a:
mixing SiCl4Adding [ BMP ]]Tf2N liquid, adding CuTfO to form SiCl as total ionic liquid4The concentration of CuTfO in the total ionic liquid is 1mol/L, the concentration of CuTfO in the total ionic liquid is 0.006mol/L, and the configured ionic liquid is stirred fully and then is subjected to ultrasonic dispersion for 1 hour until the ionic liquid is dispersed uniformly. Performing electrodeposition by a constant potential method, and controlling the potential of the working electrode to be-2.0V relative to the Pt electrode; deposition temperature: 25 ℃; deposition time: 14400 seconds.
The obtained copper-silicon composite material is used as a lithium ion battery cathode, and calculated by the mass of silicon, the capacity of 1570mAh/g can be obtained after the copper-silicon composite material is cycled for 400 times under the multiplying power of 1C, but the capacity is attenuated to 1152mAh/g after 750 cycles of cycling.
While the preferred embodiments of the present invention have been described in detail, it will be understood that the invention is not limited thereto, and that various equivalent modifications and substitutions can be made by those skilled in the art without departing from the spirit of the invention, and those skilled in the art can make equivalents and substitutions, and those equivalents and substitutions can be made within the scope of the invention as defined by the claims, such as using other types of ionic liquids as the medium, or preparing copper alloy-silylene-copper alloy, or using different semiconductor elements, such as semiconductor germanium, instead of silicon to prepare copper (alloy) -germanene-copper (alloy) composite, wherein the alloy elements include alkali metals, alkaline earth metals, lanthanides, metal Al, etc., and transition metals such as Fe, Co, and Ni, and noble metals such as platinum and rare metals titanium, zirconium, etc.

Claims (10)

1. The preparation method of the silylene-copper-silylene composite material is characterized by comprising the following steps of: in the ionic liquid, a silicon source and a copper source are subjected to electrodeposition to obtain the copper-based electrolyte; wherein:
the silicon source is SiCl4The copper in the copper source is bivalent copper;
the concentration of the copper source in the ionic liquid is 0.002-0.003 mol/L;
the potential of the electrodeposition is-1.9 to-2.1V.
2. The method of claim 1, wherein the ionic liquid is [ BMP ]]Tf2N；
And/or the silicon source is in a supersaturated state in the ionic liquid; when the ionic liquid is [ BMP ]]Tf2In the case of N, the concentration of the silicon source is preferably 0.5-1 mol/L, and more preferably 1 mol/L;
and/or the copper source is CuxRySaid R is TfO; the copper source is preferably Cu (TfO)2；
And/or the concentration of the copper source is 0.002 mol/L;
and/or the electrodeposition is constant potential electrodeposition;
and/or the potential of the electrodeposition is-1.9 to-2.0V, preferably-1.9V or-2.0V.
3. The method of preparing the silylene-copper-silylene composite of claim 1 or 2, wherein the electrodeposition is carried out in a three-electrode system comprising a working electrode, a reference electrode and a counter electrode.
4. The method of preparing a silylene-copper-silylene composite material according to claim 3, wherein the working electrode is copper, nickel, silver, gold, platinum or titanium, preferably copper;
and/or the reference electrode takes a platinum wire as an electrode material, and is completely or partially immersed in the ionic liquid to form the reference electrode; preferably, the reference electrode is in a structure of a glass tube, wherein one end of the glass tube, which is far away from the electrolyte, is open, and the end, which is in contact with the electrolyte, is filled with porous ceramic, and the inside of the glass tube is communicated with the electrolyte through the porous ceramic;
and/or the counter electrode is a graphite sheet;
and/or the distance between the working electrode and the reference electrode is 1-2 mm;
and/or the distance between the working electrode and the counter electrode is 10-40 mm.
5. The method of preparing the silylene-copper-silylene composite material of claim 1, wherein the silylene-copper-silylene composite material is prepared by first mixing the silicon source with the ionic liquid and then mixing with the copper source for a second time; preferably, said first mixing and said second mixing are carried out in a screw-top bottle;
and/or the temperature of the electrodeposition is 15-40 ℃, preferably 20-30 ℃;
and/or the electrodeposition time is 3600-7200 seconds, preferably 3600 seconds;
and/or the preparation of the silylene-copper-silylene composite is carried out under the condition that the content of oxygen and water is lower than 1ppm, and is preferably carried out in a glove box.
6. The method for preparing the silylene-copper-silylene composite material as claimed in any one of claims 1 to 5, wherein the electrode in the electrodeposition method is further subjected to polishing treatment and cleaning treatment in sequence before electrodeposition; preferably, the grinding treatment is grinding and polishing to a mirror image by using coarse-to-fine metallographic abrasive paper; preferably, the cleaning treatment sequentially comprises first water washing, acid washing and second water washing; the first washing is preferably ultrasonic cleaning by using deionized water, the pickling is preferably sulfuric acid pickling or nitric acid pickling, and the second washing is deionized water washing; preferably, the washing is carried out by washing with acetone after the washing and drying;
and/or after the electrodeposition, carrying out post-treatment on the electrode deposited with the silylene-copper-silylene composite material, wherein the post-treatment is preferably acetone cleaning.
7. A silylene-copper-silylene composite material prepared by the method for preparing the silylene-copper-silylene composite material according to any one of claims 1 to 6.
8. The composite material is characterized by comprising a structure formed by stacking a sheet material and a porous material, wherein the sheet material is a silicon olefin sheet layer, and the porous material is copper; the thickness of the silylene-copper-silylene composite material is 15-20 mu m; the thickness of the silicon sheet layer is 5-20 nm, and the length of the silicon sheet layer is 0.7-1.2 mu m.
9. Use of the silylene-copper-silylene composite material of claim 7 or 8 as a negative electrode material in an electronic device, preferably one or more of a nanoelectronic device, a spintronic device and a battery.
10. A lithium ion battery, characterized in that it employs the silylene-copper-silylene composite material according to claim 7 or 8 as a negative electrode.
CN201910717452.4A 2019-08-05 2019-08-05 Silene-copper-silylene composite material, preparation method, application and lithium ion battery Pending CN110600688A (en)

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