阅读说明：本技术 硅化合物、其制备方法与锂电池 (Silicon compound, preparation method thereof and lithium battery ) 是由 王復民 范国泰 胡阿伦 王以里 于 2020-03-25 设计创作，主要内容包括：本发明提供一种硅化合物、其制备方法与锂电池。所述硅化合物由以下化学式1表示：[化学式1](R~1)_(4-n)-Si-(L-A)_n在化学式1中,各取代基与实施方式中所定义相同。(The invention provides a silicon compound, a preparation method thereof and a lithium battery. The silicon compound is represented by the following chemical formula 1: [ chemical formula1](R 1 ) 4‑n ‑Si‑(L‑A) n In chemical formula 1, each substituent is as defined in the embodiments.)

1. A silicon compound characterized by being represented by the following chemical formula 1:

[ chemical formula 1]

(R¹)_4-n-Si-(L-A)_n

In the chemical formula 1, the first and second,

l is a linking group, and L is a linking group,

a is a carboxyl group, and the carboxyl group,

R¹each independently hydrogen, halogen atom, alkyl group, aryl group, alkoxy group or hydroxyl group,

n is an integer of 0 to 4,

when n is 2 or more, L may be the same or different groups.

2. The silicon compound of claim 1, wherein the linking group comprises an alkylene, arylene, heteroarylene, alkyleneoxy, cycloalkylene, amide, carbonyloxy, a divalent group with a halogen, or a combination thereof.

3. A method of preparing a silicon compound, comprising:

providing an olefin reactant; and

linking the olefin reactant to the silicon reactant via a hydrosilylation reaction to obtain a silicon compound,

wherein the silicon reactant has at least one silane functional group,

wherein the olefin reactant comprises a terminal olefin functional group, a terminal carboxyl group, and a linking group linking the terminal olefin functional group and the terminal carboxyl group.

4. The method for producing a silicon compound according to claim 3, wherein the silicon reactant is composed of (R)_4-n-Si-(H)_nIt is shown that,

wherein each R is independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a hydroxyl group,

n is an integer of 1 to 4.

5. The method for producing a silicon compound according to claim 3, wherein the linking group includes an alkylene group, an arylene group, a heteroarylene group, an alkyleneoxy group, a cycloalkylene group, an amide group, a carbonyloxy group, a divalent group having a halogen, or a combination thereof.

6. The method for producing a silicon compound according to claim 3, wherein the olefin reactant includes (meth) acrylic acid, or carboxyethyl acrylate.

7. A method of preparing a silicon compound, comprising:

providing a first olefin reactant;

linking the first olefin reactant to a silicon reactant via a hydrosilylation reaction to obtain an intermediate product; and

contacting a second olefinic reactant with said intermediate product, such that said second olefinic reactant is linked to said intermediate product, to obtain a silicon compound,

wherein the silicon reactant has at least one silane functional group,

wherein the first olefinic reactant includes a first terminal olefinic functional group, a group reactive with the olefinic functional group, and a first linking group linking the first terminal olefinic functional group and the group reactive with the olefinic functional group, and

the second alkene reactant includes a second terminal alkene functional group, a terminal carboxyl group, and a second linking group linking the second terminal alkene functional group and the terminal carboxyl group.

8. The method for producing a silicon compound according to claim 7, wherein the silicon reactant is composed of (R)_4-n-Si-(H)_nIt is shown that,

wherein each R is independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a hydroxyl group,

n is an integer of 1 to 4.

9. The method for producing a silicon compound according to claim 7, wherein the first linking group includes an alkylene group, an arylene group, a heteroarylene group, an alkyleneoxy group, a cycloalkylene group, an amide group, a carbonyloxy group, a divalent group having a halogen, or a combination thereof.

10. The method for producing a silicon compound according to claim 7, wherein the second linking group includes an alkylene group, an arylene group, a heteroarylene group, an alkyleneoxy group, a cycloalkylene group, an amide group, a carbonyloxy group, a divalent group having a halogen, or a combination thereof.

11. The method for producing a silicon compound according to claim 7, wherein the group reactive with an olefin functional group comprises a halogenated alkyl group.

12. The process for producing a silicon compound according to claim 7, wherein the first olefin reactant comprises allyl 2-bromo-2-methylpropionate.

13. The process for producing a silicon compound according to claim 7, wherein the second olefin reactant comprises (meth) acrylic acid, acrylic acid or carboxyethyl acrylate.

14. A lithium battery, comprising:

a cathode;

an anode disposed separately from the cathode and comprising the silicon compound according to claim 1 or 2;

the isolating film is arranged between the cathode and the anode, and the isolating film, the cathode and the anode define an accommodating area;

the electrolyte is arranged in the accommodating area; and

and the packaging structure coats the cathode, the anode and the electrolyte.

15. A lithium battery as in claim 14, wherein the electrolyte comprises an organic solvent, a lithium salt, and an additive.

16. The lithium battery of claim 15, wherein the additive comprises mono-maleimide, polymaleimide, bismaleimide, polybismaleimide, a copolymer of bismaleimide and mono-maleimide, vinylene carbonate, or mixtures thereof.

Technical Field

The present invention relates to a silicon compound, a method for preparing the same, and a battery, and more particularly, to a silicon compound for a lithium battery, a method for preparing the same, and a lithium battery.

Background

Silicon has been a material that is urgently commercialized in science and industry because of its very high energy density (4000mAh/g) and high global reserves. However, in addition to the fact that the reaction mechanism of silicon and lithium ions is quite different from that of graphite and lithium ions, the volume of the alloy after the reaction of silicon and lithium expands rapidly, which leads to the problem that the material is easy to crack and the generated fracture surface is easy to react with the electrolyte solution, and the problem is repeated, finally resulting in poor cycle life of the material, thus limiting the current applicability of the silicon material.

There are many developments to improve the above disadvantages, such as the use of new electrolyte additives (e.g. fluoroethylene carbonate (FEC)), the use of new adhesive systems (e.g. Polyimide (PI)) or alloy systems (e.g. silicon tin), etc. However, the above-mentioned disadvantages cannot be completely improved by the above-mentioned improvement methods.

Disclosure of Invention

The present invention provides a silicon compound which can be applied to an anode material of a lithium battery, so that the lithium battery has a good battery life.

The invention provides a method for preparing a silicon compound, and the prepared silicon compound can be applied to an anode material of a lithium battery, so that the lithium battery has a good battery life.

The invention provides a lithium battery, which is provided with the silicon compound.

The present invention provides a silicon compound represented by the following chemical formula 1:

[ chemical formula 1]

(R¹)_4-n-Si-(L-A)_n

In the chemical formula 1, the first and second,

l is a linking group (linker),

a is a carboxyl group, and the carboxyl group,

R¹each independently hydrogen, halogen atom, alkyl group, aryl group, alkoxy group or hydroxyl group,

n is an integer of 0 to 4,

when n is 2 or more, L may be the same or different groups.

In an embodiment of the invention, the linking group is, for example, alkylene (arylene), arylene (arylene), heteroarylene (heteroarylene), alkyleneoxy (alkyleneoxy), cycloalkylene (cycloalkyleneoxy), amide (amide), carbonyloxy (carbonyloxy), a divalent group having halogen, or a combination thereof.

The present invention provides a method for preparing a silicon compound, which comprises the following steps. First, an olefin reactant is provided. The olefin reactant is then coupled to the silicon reactant via a Hydrosilylation (Hydrosilylation) reaction to yield a silicon compound. The silicon reactant has at least one silane functional group, wherein the olefin reactant includes a terminal olefin functional group, a terminal carboxyl group, and a linking group linking the terminal olefin functional group and the terminal carboxyl group.

In one embodiment of the present invention, the silicon reactant is selected from (R)_4-n-Si-(H)_nWherein each R is independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a hydroxyl group, and n is an integer of 1 to 4.

In an embodiment of the invention, the linking group is, for example, alkylene (arylene), arylene (arylene), heteroarylene (heteroarylene), alkyleneoxy (alkyleneoxy), cycloalkylene (cycloalkyleneoxy), amide (amide), carbonyloxy (carbonyloxy), a divalent group having halogen, or a combination thereof.

In an embodiment of the present invention, the olefin reactant is (meth) acrylic acid, or carboxyethyl acrylate (carboxyethyl acrylate), for example.

The present invention provides a method for preparing a silicon compound, which comprises the following steps. First, a first olefin reactant is provided. Next, a first olefin reactant is coupled to the silicon reactant via a Hydrosilylation (Hydrosilylation) reaction to yield an intermediate product. The second olefinic reactant is then contacted with the intermediate product to link the second olefinic reactant to the intermediate product to obtain the silicon compound. The silicon reactant has at least one silane functional group (silane functional group), wherein the first alkene reactant includes a first terminal alkene functional group, a group reactive with the alkene functional group, and a first linking group linking the first terminal alkene functional group and the group reactive with the alkene functional group, and the second alkene reactant includes a second terminal alkene functional group, a terminal carboxyl group, and a second linking group linking the second terminal alkene functional group and the terminal carboxyl group.

In one embodiment of the present invention, the silicon reactant is selected from (R)_4-n-Si-(H)_nWherein each R is independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a hydroxyl group, and n is an integer of 1 to 4.

In an embodiment of the invention, the first linking group is, for example, alkylene (arylene), arylene (arylene), heteroarylene (heteroarylene), alkyleneoxy (alkyleneoxy), cycloalkylene (cycloalkyleneoxy), amide (amide), carbonyloxy (carbonyloxy), a divalent group having halogen, or a combination thereof.

In an embodiment of the invention, the second linking group is, for example, alkylene (arylene), arylene (arylene), heteroarylene (heteroarylene), alkyleneoxy (alkyleneoxy), cycloalkylene (cycloalkylene), amide (amide), carbonyloxy (carbonyloxy), a divalent group having halogen, or a combination thereof.

In an embodiment of the present invention, the group capable of reacting with the olefin functional group is, for example, alkyl halide (alkyl halide).

In an embodiment of the present invention, the first olefin reactant is allyl-2-bromo-2-methylpropionate (allyl-2-bromo-2-methylpropionate), for example.

In an embodiment of the present invention, the second olefin reactant is (meth) acrylic acid, or carboxyethyl acrylate (carboxyethyl acrylate), for example.

Based on the above, when the silicon compound of the present invention is used as an anode material of a lithium battery, and the polymer brush grafted to the silicon compound of the present invention is used as an elastomer, the swelling after the reaction of silicon and lithium can be suppressed, and the problem of material cracking can be reduced. In addition, the polymer brush grafted on the silicon compound can avoid excessive contact with the electrolyte, so that the problem of excessive passive film formation caused by electrolyte cracking is reduced, the internal resistance of the battery can be obviously reduced, and the service life of the lithium battery is prolonged.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

FIG. 1 is a schematic cross-sectional view of a lithium battery according to an embodiment of the invention;

FIG. 2 is a life cycle diagram of lithium batteries of Experimental example 4 and comparative example 1;

FIG. 3 is a life cycle diagram of a lithium battery of experimental example 5;

fig. 4 is a life cycle diagram of lithium batteries of experimental example 6 and comparative example 1.

Detailed Description

In this context, a range denoted by "a numerical value to another numerical value" is a general expression avoiding a recitation of all numerical values in the range in the specification. Thus, recitation of a range of values herein is intended to encompass any value within the range and any smaller range defined by any value within the range, as if the range and smaller range were explicitly recited in the specification.

The present invention provides a silicon compound which can achieve the above-mentioned advantages in order to prepare a high-energy silicon material which can be applied to an anode material for a lithium battery to provide the lithium battery with good performance. Hereinafter, specific examples will be described as examples to explain the present invention.

[ silicon Compound of the present invention ]

An embodiment of the present invention provides a silicon compound represented by the following chemical formula 1:

[ chemical formula 1]

(R¹)_4-n-Si-(L-A)_n

In the chemical formula 1, the first and second,

l is a linking group (linker),

a is a carboxyl group, and the carboxyl group,

R¹each independently hydrogen, halogen atom, alkyl group, aryl group, alkoxy group or hydroxyl group,

n is an integer of 0 to 4,

when n is 2 or more, L may be the same or different groups.

In one embodiment of the present invention, the linking group includes alkylene (arylene), arylene (arylene), heteroarylene (heteroarylene), alkyleneoxy (alkyleneoxy), cycloalkylene (cycloalkylene), amide (amide), carbonyloxy (carbonyloxy), divalent group having halogen, or a combination thereof.

In one embodiment, the linking group is, for example, alkylene (alkylene) of C1 to C12, arylene (arylene) of C6 to C15, heteroarylene (heteroarylene) of C2 to C12, alkyleneoxy (alkylene oxide) of C1 to C12, cycloalkylene (cycloalkylene) of C3 to C12, amide (amide), carbonyloxy (carbonyloxy), or a divalent group having halogen, but the invention is not limited thereto.

[ Process for producing silicon Compound of the present invention ]

A first embodiment of the present invention provides a method of preparing a silicon compound, which includes the following steps. First, an olefin reactant is provided, wherein the olefin reactant includes a terminal olefin functional group, a terminal carboxyl group, and a linking group that links the terminal olefin functional group and the terminal carboxyl group.

In one embodiment, the linking group includes an alkylene (alkylene), arylene (arylene), heteroarylene (heteroarylene), alkyleneoxy (alkylene oxide), cycloalkylene (cycloalkylene), amide (amide), carbonyloxy (carbonyloxy), a divalent group having a halogen, or a combination thereof.

In one embodiment, the linking group is, for example, alkylene (alkylene) of C1 to C12, arylene (arylene) of C6 to C15, heteroarylene (heteroarylene) of C2 to C12, alkyleneoxy (alkylene oxide) of C1 to C12, cycloalkylene (cycloalkylene) of C3 to C12, amide (amide), carbonyloxy (carbonyloxy), or a divalent group having halogen, but the invention is not limited thereto.

In one embodiment, the olefin reactant is, for example, (meth) acrylic acid, or carboxyethyl acrylate (CEA), but the invention is not limited thereto.

Subsequently, the olefin reactant is connected to the silicon reactant via a Hydrosilylation (Hydrosilylation) reaction to obtain a silicon compound. In this embodiment, the silicon reactant has at least one silane functional group (silane functional group).

In this embodiment, the olefin reactant may be linked to the silicon reactant via a hydrosilylation reaction between its terminal olefin functional groups and the silane functional groups (-SH) of the silicon reactant to obtain the silicon compound.

In one embodiment, the silicon reactant is composed of (R)_4-n-Si-(H)_nWherein each R is independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a hydroxyl group, and n is an integer of 1 to 4. In one embodiment, the silicon reactant has 4 silane functional groups (i.e., n is 4), that is, a silicon reactant having 4 silane functional groups (-SH) can be combined with 4 olefin reactants. In another embodiment, the silicon atoms of the silicon reactant may have other substituents bonded thereto in addition to the silane functional groups (-SH).

In one embodiment, the silicon reactant is a hydrofluoric acid treated silicon material, for example. In one embodiment, the silicon reactant is, for example, silicon nanoparticles treated with hydrofluoric acid. Hydrofluoric acid treated silicon materials (or silicon nanoparticles) are etched on their surface to produce silane functional groups (-SH). The silane functional group of the silicon reactant and the olefin functional group of the olefin reactant can undergo a hydrosilylation reaction to graft an olefin compound having an olefin functional group at one end and a carboxyl group at the other end on the silicon reactant to achieve a modification effect of the silicon reactant, and the resulting modification is called a polymer brush (polymer brush).

In this example, the hydrosilylation reaction of the olefin reactant and the silicon reactant was carried out in the presence of a hydrosilylation catalyst and under conditions to promote hydrosilylation. In this example, the hydrosilylation catalyst is a metal complex that increases the rate of the hydrosilylation reaction and/or shifts the equilibrium of the hydrosilylation reaction. In this example, a hydrosilylation catalyst is selected that is compatible with the functional groups on the reactants. In one embodiment, the hydrosilylation catalyst is, for example, chloroplatinic acid, divinyltetramethyldisiloxane platinum complex (Pt-dvs), tris (triphenylphosphine) rhodium chloride (1) (tris (triphenylphosphine) Rh (1) chloride), bis (diphenylphosphine) dinaphthylpalladium dichloride (bis (diphenylphosphino) binapthylpalladium dichloride) or dioctylcarbonyldicobalt (dicobalt dithiolcarbonyl), but the present invention is not limited thereto. In this example, in order to promote the hydrosilylation reaction, the reaction temperature of the hydrosilylation reaction may be higher than room temperature. In one embodiment, the reaction temperature for the hydrosilylation reaction is 40 ℃ to 100 ℃.

In this example, the number of moles of unsaturated carbon (alkene functional group) of the alkene reactant in the reaction is greater than or equal to the number of moles of silane functional group of the silicon reactant in the reaction.

A second embodiment of the present invention provides a method for preparing a silicon compound, which includes the following steps. First, a first olefin reactant is provided, wherein the first olefin reactant includes a terminal olefin functional group, a group reactive with the olefin functional group, and a linking group that links the terminal olefin functional group and the group reactive with the olefin functional group.

In one embodiment, the linking group of the first olefin reactant includes an alkylene (arylene), arylene (arylene), heteroarylene (heteroarylene), alkyleneoxy (alkyleneoxy), cycloalkylene (cycloalkyleneoxy), amide (amide), carbonyloxy (carbonyloxy), a divalent group having a halogen, or a combination thereof.

In one embodiment, the linking group of the first olefin reactant is, for example, alkylene (alkylene) of C1 to C12, arylene (arylene) of C6 to C15, heteroarylene (heteroarylene) of C2 to C12, alkyleneoxy (alkylene oxide) of C1 to C12, cycloalkylene (cycloalkylene) of C3 to C12, amide (amide), carbonyloxy (carbonyloxy), divalent group having halogen, but the invention is not limited thereto.

In this embodiment, one end of the first olefin reactant has an olefin functional group that can undergo a hydrosilylation reaction with a silane functional group of the silicon reactant, thereby bonding the first olefin reactant and the silicon reactant. The other end of the first olefin reactant has a group reactive with the olefin functional group that reacts with the olefin functional group of a subsequent second olefin reactant to link the second olefin reactant to the first olefin reactant. In this embodiment, the group of the first olefin reactant that is reactive with the olefin functional group is, for example, an alkyl halide. In this example, the first olefin reactant is, for example, allyl-2-bromo-2-methylpropionate.

Then, the first olefin reactant is connected to the silicon reactant through a Hydrosilylation (Hydrosilylation) reaction to obtain an intermediate product formed by bonding the first olefin reactant and the silicon reactant.

In one embodiment, the silicon reactant is composed of (R)_4-n-Si-(H)_nWherein each R is independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a hydroxyl group, and n is an integer of 1 to 4. In one embodiment, the silicon reactant has 4 silane functional groups (i.e., n is 4), that is, a silicon reactant having 4 silane functional groups (-SH) can be combined with 4 first olefin reactants. In another embodiment, the silicon atoms of the silicon reactant may have other substituents bonded thereto in addition to the silane functional groups (-SH).

In one embodiment, the silicon reactant is a hydrofluoric acid treated silicon material, for example. In one embodiment, the silicon reactant is, for example, silicon nanoparticles treated with hydrofluoric acid. Hydrofluoric acid treated silicon materials (or silicon nanoparticles) are etched on their surface to produce silane functional groups (-SH).

In this example, the hydrosilylation reaction of the first olefin reactant with the silicon reactant is conducted in the presence of a hydrosilylation catalyst and under conditions that promote hydrosilylation. In this example, the hydrosilylation catalyst is a metal complex that increases the rate of the hydrosilylation reaction and/or shifts the equilibrium of the hydrosilylation reaction. In this example, a hydrosilylation catalyst is selected that is compatible with the functional groups on the reactants. In one embodiment, the hydrosilylation catalyst is, for example, chloroplatinic acid, divinyltetramethyldisiloxane platinum complex (Pt-dvs), tris (triphenylphosphine) rhodium chloride (1) (tris (triphenylphosphine) Rh (1) chloride), bis (diphenylphosphine) dinaphthylpalladium dichloride (bis (diphenylphosphino) binapthylpalladium dichloride) or dioctylcarbonyldicobalt (dicobalt dithiolcarbonyl), but the present invention is not limited thereto. In this example, in order to promote the hydrosilylation reaction, the reaction temperature of the hydrosilylation reaction may be higher than room temperature. In one embodiment, the reaction temperature for the hydrosilylation reaction is 40 ℃ to 100 ℃.

In this example, the moles of unsaturated carbon (olefin functional groups) of the first olefin reactant in the reaction are greater than or equal to the moles of silane functional groups of the silicon reactant in the reaction.

The second olefinic reactant is then contacted with the intermediate product to link the second olefinic reactant to the intermediate product to obtain the silicon compound. In this embodiment, the second olefinic reactant includes a terminal olefinic functional group, a terminal carboxyl group, and a linking group linking the terminal olefinic functional group and the terminal carboxyl group.

In one embodiment, the linking group of the second alkene reactant includes an alkylene (alkylene), an arylene (arylene), a heteroarylene (heteroarylene), an alkyleneoxy (alkylene oxide), a cycloalkylene (cycloalkylene), an amide (amide), a carbonyloxy (carbonyl oxide), a divalent group having a halogen, or a combination thereof.

In one embodiment, the linking group of the second olefin reactant is, for example, alkylene (alkylene) of C1 to C12, arylene (arylene) of C6 to C15, heteroarylene (heteroarylene) of C2 to C12, alkyleneoxy (alkylene oxide) of C1 to C12, cycloalkylene (cycloalkylene) of C3 to C12, amide (amide), carbonyloxy (carbonyloxy), divalent group having halogen, but the invention is not limited thereto.

In one embodiment, the second olefinic reactant is, for example, (meth) acrylic acid, or carboxyethyl acrylate.

In this embodiment, the second olefin reactant may be attached to the intermediate product via reaction of its terminal olefin functional group with a group of the intermediate product (specifically, the portion of the first olefin reactant in the intermediate product) that is reactive with the olefin functional group to yield a silicon oxide. For example, the second olefin reactant may react via its terminal olefin functional group with the halogen atom of the halogenated alkyl group of the first olefin reactant to attach the second olefin reactant to the intermediate product.

In this embodiment, when the group of the first olefin reactant that can react with the olefin functional group is a halogenated alkyl group, a reaction catalyst may be further added to allow a radical polymerization reaction to proceed while the second olefin reactant is linked to the first olefin reactant. In this example, the reaction catalyst is, for example, copper bromide/2, 2' -bipyridine (CuBr/Bipy).

In this embodiment, when the silicon compound of the present invention is used as an anode material for a lithium battery, the polymer brush grafted to the silicon compound can serve as an elastomer, which can suppress the swelling after the reaction of silicon with lithium and reduce the problem of material cracking. In addition, the polymer brush grafted on the silicon compound can avoid excessive contact with the electrolyte, thereby reducing the problem of excessive passive film formation caused by electrolyte cracking, and obviously reducing the internal resistance of the battery.

Fig. 1 is a schematic cross-sectional view of a lithium battery according to an embodiment of the present invention. Referring to fig. 1, a lithium battery 100 includes an anode 102, a cathode 104, a separator 106, an electrolyte 108, and a package structure 112.

The anode 102 includes an anode metal foil 102a and an anode material 102b, wherein the anode material 102b is disposed on the anode metal foil 102a by coating or sputtering. The anode metal foil 102a is, for example, a copper foil, an aluminum foil, a nickel foil, or a highly conductive stainless steel foil. In the present embodiment, the anode material 102b includes the silicon compound of the present invention. In an embodiment, the anode material 102b may further include carbide or metallic lithium. The carbide is, for example, carbon powder, graphite, carbon fiber, carbon nanotube, graphene, or a mixture thereof. However, in other embodiments, the anode 102 may also include only the anode material 102 b.

The silicon compound is contained in an amount of 5 to 85 parts by weight (preferably 10 to 50 parts by weight) based on 100 parts by weight of the total weight of the anode material 102 b.

The cathode 104 is disposed separately from the anode 102. The cathode 104 includes a cathode metal foil 104a and a cathode material 104b, wherein the cathode material 104b is disposed on the cathode metal foil 104a by coating. The cathode metal foil 104a is, for example, a copper foil, an aluminum foil, a nickel foil, or a highly conductive stainless steel foil. The cathode material 104b includes a lithium mixed transition metal oxide (li-m mixed transition metal oxide). Oxides of lithium mixed with transition metals, e.g. LiMnO₂、LiMn₂O₄、LiCoO₂、Li₂Cr₂O₇、Li₂CrO₄、LiNiO₂、LiFeO₂、LiNi_xCo_1-xO₂、LiFePO₄、LiMn_0.5Ni_0.5O₂、LiMn_1/3Co_1/3Ni_1/3O₂、LiMc_0.5Mn_1.5O₄Or a combination thereof, wherein 0<x<1, Mc is a divalent metal.

In addition, the lithium battery 100 may further include a polymer binder. The polymeric binder reacts with the anode 102 and/or the cathode 104 to increase the mechanical properties of the electrode. Specifically, the anode material 102b may be adhered to the anode metal foil 102a by a polymer adhesive, and the cathode material 104b may be adhered to the cathode metal foil 104a by a polymer adhesive. The high molecular adhesive is, for example, polyvinylidene fluoride (PVDF), Styrene Butadiene Rubber (SBR), polyamide, melamine resin, or a combination thereof.

The isolation film 106 is disposed between the anode 102 and the cathode 104, and the isolation film 106, the anode 102 and the cathode 104 define a receiving area 110. The material of the isolation film 106 is an insulating material, such as Polyethylene (PE), polypropylene (PP), or a composite structure (e.g., PE/PP/PE) composed of the above materials.

The electrolyte 108 is disposed in the accommodating area 110. The electrolyte 108 includes an organic solvent, a lithium salt, and an additive. The addition amount of the organic solvent accounts for 55 wt% to 90 wt% of the electrolyte 108, the addition amount of the lithium salt accounts for 10 wt% to 35 wt% of the electrolyte 108, and the addition amount of the additive accounts for 0.05 wt% to 10 wt% of the electrolyte 108. However, in other embodiments, the electrolyte 108 may not contain additives.

Organic solvents are for example gamma-butyl lactone, Ethylene Carbonate (EC), propylene carbonate, diethyl carbonate (DEC), Propyl Acetate (PA), dimethyl carbonate (DMC), Ethyl Methyl Carbonate (EMC) or combinations thereof.

The lithium salt being, for example, LiPF₆、LiBF₄、LiAsF₆、LiSbF₆、LiClO₄、LiAlCl₄、LiGaCl₄、LiNO₃、LiC(SO₂CF₃)₃、LiN(SO₂CF₃)₂、LiSCN、LiO₃SCF₂CF₃、LiC₆F₅SO₃、LiO₂CCF₃、LiSO₃F、LiB(C₆H₅)₄、LiCF₃SO₃Or a combination thereof.

Additives are, for example, mono-maleimide, polymaleimide, bismaleimide, copolymers of bismaleimide with mono-maleimide, Vinylene Carbonate (VC), or mixtures thereof. The monomaleimide is, for example, selected from the group consisting of N-phenylmaleimide, N- (o-methylphenyl) -maleimide, N- (m-methylphenyl) -maleimide, N- (p-methylphenyl) -maleimide, N-cyclohexylmaleimide, maleimidophenol, maleimidobenzocyclobutene, phosphorus-containing maleimide, phospho-maleimide, oxysilylmaleimide, N- (tetrahydropyranyl-oxyphenyl) maleimide and 2, 6-ditolyl maleimide.

The encapsulation structure 112 encapsulates the anode 102, the cathode 104, and the electrolyte 108. The material of the package structure 112 is, for example, aluminum foil.

In particular, the anode 102 can be formed by adding the silicon compound of the present invention to the anode material in the conventional battery manufacturing process, so that the battery efficiency and the charge-discharge cycle life of the lithium battery 100 can be effectively maintained without changing any battery design, other electrode materials and electrolyte, and the lithium battery 100 has higher safety.

The effects of the silicon compound of the present invention will be described below in experimental examples and comparative examples.

[ preparation of silicon Compound ]

Example 1: preparation of silicon Compound 1

[ reaction scheme 1]

A1.5 g sample of silicon nanoparticles (SiNPs) was dispersed in a polyethylene centrifuge tube containing 20mL of ethanol and subjected to ultrasonic oscillation for 15 minutes using an ultrasonic water bath. Then, 1.2mL of a 48% hydrofluoric acid solution dissolved in 25mL of deionized water was added to the mixture, and the ultrasonication was continued for 20 minutes. The solid powder was then collected by successive water washes of ethanol and deionized water and centrifugation at 4000 rpm. The hydrogen-terminated silicon nanoparticles collected by centrifugation were dried in a vacuum oven at 80 ℃ overnight and were referred to as H-SiNPs and used as a silicon reactant.

Next, 0.8g of H-SiNPs was added to 20ml of ethanol and transferred to a round-bottomed flask containing 20% acrylic acid (160mg) as an olefin reactant and 4mg of Pt-dvs as a catalyst. The reaction mixture was refluxed at 70 ℃ under a stream of nitrogen. In the above process, acrylic acid is subjected to a hydrosilylation reaction with hydrogen-terminated silicon nanoparticles to graft acrylic acid on the silicon nanoparticles. To further initiate the radical polymerization of acrylic acid grafted on the surface of the silicon nanoparticles, 0.032g of potassium persulfate (KPS) as an initiator was dissolved in 5mL of deionized water and added to the above solution with a syringe. An in situ (in-situ) polymerization reaction was further carried out at 70 ℃ for 24 hours with the aid of nitrogen gas to obtain the silicon compound 1.

Example 2: preparation of silicon Compound 2

A1.5 g sample of silicon nanoparticles (SiNPs) was dispersed in a polyethylene centrifuge tube containing 20mL of ethanol and subjected to ultrasonic oscillation for 15 minutes using an ultrasonic water bath. Then, 1.2mL of a 48% hydrofluoric acid solution dissolved in 25mL of deionized water was added to the mixture, and the ultrasonication was continued for 20 minutes. The solid powder was then collected by successive water washes of ethanol and deionized water and centrifugation at 4000 rpm. The hydrogen-terminated silicon nanoparticles collected by centrifugation were dried in a vacuum oven at 80 ℃ overnight and were referred to as H-SiNPs and used as a silicon reactant.

Next, 0.8g of H-SiNPs was added to 20ml of ethanol and transferred to a round-bottomed flask containing 30% carboxyethyl acrylate (248mg) as an olefin reactant and 4mg of Pt-dvs as a catalyst. The reaction mixture was refluxed at 70 ℃ under a stream of nitrogen. In the above process, acrylic acid is subjected to a hydrosilylation reaction with hydrogen-terminated silicon nanoparticles to graft acrylic acid on the silicon nanoparticles. To further initiate the radical polymerization of acrylic acid grafted on the surface of the silicon nanoparticles, 0.032g of potassium persulfate (KPS) as an initiator was dissolved in 5mL of deionized water and added to the above solution with a syringe. An in-situ (in-situ) polymerization reaction was further carried out at 70 ℃ for 24 hours with the aid of nitrogen gas to obtain the silicon compound 2.

Example 3: preparation of silicon Compound 3

[ reaction scheme 2]

A0.5 g sample of silicon nanoparticles (SiNPs) was dispersed in a polyethylene centrifuge tube containing 20mL of ethanol and subjected to ultrasonic oscillation for 15 minutes using an ultrasonic water bath. Then, 1.2mL of a 48% hydrofluoric acid solution dissolved in 25mL of deionized water was added to the mixture, and the ultrasonication was continued for 20 minutes. The solid powder was then collected by successive water washes of ethanol and deionized water and centrifugation at 4000 rpm. The hydrogen-terminated silicon nanoparticles collected by centrifugation were dried in a vacuum oven at 80 ℃ overnight and were referred to as H-SiNPs and used as a silicon reactant.

Next, 0.8g of H-SiNPs was added to 7ml of Tetrahydrofuran (THF), and transferred to a round-bottomed flask containing 4. mu.L of allyl 2-bromo-2-methylpropionate as a first olefin reactant and 4mg of Pt-dvs as a catalyst. The reaction mixture was carried out at 60 ℃ for 24 hours under a nitrogen gas flow, and the product was named SiNPs-macromolecular initiator (SiNPs-macroinitiator). In the above process, the first olefin reactant is subjected to a hydrosilylation reaction with the hydrogen-terminated silicon nanoparticles to graft the first olefin reactant on the silicon nanoparticles.

Then, 0.32g of SiNPs-macromolecular initiator, 1g of acrylic acid and 60mg of Bipy were mixed, and then 20mg of CuBr was added to the above mixture and subjected to radical polymerization at room temperature for 24 hours. The resultant was washed with EDTA and ethanol and dried in an oven to obtain silicon compound 3.

[ example 4]

[ preparation of Anode ]

Silicon compound 1, carbon black (Super-P) as a conductive agent, and carboxymethyl cellulose sodium salt (CMC-Na) as a binder were mixed in a weight ratio of 60:20: 20. First, the binder material was stirred in water solvent for 24 hours at 600rpm using a magnetic stirrer. Next, the anode active material (i.e., silicon compound 1), Super-P, and the sodium carboxymethyl cellulose aqueous solution were mixed at 600rpm for 12 hours using a magnetic stirrer to prepare a slurry. The prepared slurry was then spread into fresh copper foil using a 100 μm doctor blade and dried under vacuum at 90 ℃ for 3 hours and then dried in a vacuum oven at 100 ℃ overnight. After that, the dried electrode is pressed in a roll mill to stabilize the contact between the substrate and the current collector. Thus, the anode of this example was obtained.

[ preparation of cathode ]

The cathode adopts a lithium metal sheet.

[ preparation of electrolyte ]

Mixing LiPF₆Dissolved in a mixed solution (volume ratio PC/EC/DEC: 2/3/5) of Propylene Carbonate (PC), Ethylene Carbonate (EC), and diethyl carbonate (DEC) as an organic solvent in an electrolyte, LiPF, to prepare an electrolyte solution having a concentration of 1M₆As lithium salts in electrolytes

[ production of lithium batteries ]

After the anode and the cathode are separated by taking polypropylene as a separation film and an accommodating area is defined, the electrolyte is added into the accommodating area between the anode and the cathode. Finally, the above structure is sealed with a package structure, and the lithium battery of example 4 is completed.

[ example 5]

The anode, cathode, electrolyte and lithium battery of example 5 were prepared following a similar preparation procedure as example 1, with the only differences: in the anode of example 5, the anode active material used was silicon compound 2 instead of silicon compound 1.

[ example 6]

The anode, cathode, electrolyte and lithium battery of example 6 were prepared following a similar preparation procedure as example 1, with the only differences: in the anode of example 6, the anode active material used was silicon compound 3 instead of silicon compound 1.

Comparative example 1

The anode, cathode, electrolyte and lithium battery of comparative example 1 were prepared according to a similar preparation procedure as example 1, with the only difference that: in the anode of comparative example 1, the anode active material used was unmodified raw silicon nanoparticles instead of the silicon compound 1.

Next, the lithium batteries of example 4, example 5, example 6 and comparative example 1 were subjected to cycle life tests. Fig. 2 is a life cycle diagram of lithium batteries of experimental example 4 and comparative example 1. Fig. 3 is a life cycle diagram of the lithium battery of experimental example 5. Fig. 4 is a life cycle diagram of lithium batteries of experimental example 6 and comparative example 1.

As is apparent from fig. 2 to 4, when the lithium battery has the silicon compound of the present invention (i.e., experimental examples 4 to 6) as compared to the lithium battery having unmodified raw silicon nanoparticles (i.e., comparative example 1), the cycle life of the lithium batteries of experimental examples 4 to 6 is significantly higher than that of comparative example 1, which indicates that the silicon compound of the present invention can effectively improve the battery performance. Specifically, when the silicon compound of the present invention is used as an anode material for a lithium battery, the polymer brush grafted on the silicon compound can serve as an elastomer and can serve as a negatively charged functional group, which can facilitate dispersion of a slurry and suppress swelling after the reaction of silicon with lithium and reduce the problem of material cracking. In addition, the polymer brush grafted on the silicon compound can avoid excessive contact with the electrolyte, so that the problem of excessive passive film formation caused by electrolyte cracking is reduced, the internal resistance of the battery can be obviously reduced, and the service life of the lithium battery is prolonged.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.