WO2017206062A1

WO2017206062A1 - Secondary battery and preparation method therefor

Info

Publication number: WO2017206062A1
Application number: PCT/CN2016/084111
Authority: WO
Inventors: 唐永炳; 季必发; 张帆
Original assignee: 深圳先进技术研究院
Priority date: 2016-05-31
Filing date: 2016-05-31
Publication date: 2017-12-07
Also published as: CN109565074A

Abstract

Provided are a secondary battery and a preparation method therefor. The secondary battery comprises a battery negative electrode (1), an electrolyte solution (2), a separator (3), and a battery positive electrode (4). The battery positive electrode (4) comprises a positive electrode current collector (42) and a positive electrode active material layer (41). The positive electrode active material layer (41) comprises a positive electrode active material, and the positive electrode active material has a layered crystal structure. The electrolyte solution (2) comprises electrolyte and a solvent. The electrolyte is a magnesium salt. The battery negative electrode (1) comprises one or more of a metal, a metal alloy or a metal composition conductive material. The secondary battery can reduce the weight and the volume of a battery, can improve the energy density of the battery, and can improve the selectivity of negative electrode materials. The involved electrochemical process is a binary ionic reaction. The problem of difficulty of intercalation/deintercalation of magnesium ions of a positive electrode active material in a magnesium ion battery in the prior art is avoided.

Description

Secondary battery and preparation method thereof

Technical field

The present invention relates to the field of batteries, and in particular to a secondary battery and a method of fabricating the same.

Background technique

A secondary battery, also called a rechargeable battery, is a battery that can be repeatedly charged and discharged and used multiple times. Compared with a non-reusable primary battery, the secondary battery has the advantages of low cost of use and low environmental pollution. At present, the main secondary battery technologies are lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries. Among them, lithium ion batteries are the most widely used. However, lithium-ion batteries face the disadvantages of limited lithium resource reserves and high cost. As an energy storage technology that potentially replaces lithium-ion batteries, magnesium-ion batteries have received increasing attention in recent years. The working principle of a magnesium ion battery is similar to that of a lithium ion battery, but the storage and release of charge in the battery is achieved by the migration of magnesium ions. The core component of the magnesium ion battery comprises a positive electrode, a negative electrode and an electrolyte, which realizes energy storage and release by a redox reaction in which ion transport and electron transport phase separation occurs at the interface between the positive electrode, the negative electrode and the electrolyte. During charging, magnesium ions are removed from the positive electrode active material and embedded in the negative electrode active material; upon discharge, magnesium ions are extracted from the negative electrode active material and embedded in the positive electrode active material. Common magnesium ion batteries are transition metal oxides (V ₂ O ₅ , MoO ₃ , MnO ₂ ), transition metal sulfides (such as TiS ₂ , MoS ₂ ), polyanionic phosphates or silicate materials (Mg _x FeSiO ₄ ) or the like is a positive electrode active material, and an alloy material of magnesium metal or magnesium is a negative electrode active material. Since the ion radius of magnesium ion is small and the charge density is large, when the existing magnesium ion battery is charged and discharged, the magnesium ion is easily inserted into the positive electrode in the form of solvation in the process of being extracted and embedded in the positive electrode material, and the magnesium ion is extracted and embedded. The greater difficulty has seriously restricted the development of this type of battery.

Summary of the invention

In order to overcome the above technical problems, the present invention provides a secondary battery and a method of preparing the same.

In a first aspect, the present invention provides a secondary battery comprising a battery negative electrode, an electrolyte, a separator, and a battery positive electrode, wherein the battery positive electrode includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode An active material, the positive active material having a layered crystal structure; the electrolyte comprising an electrolyte and a solvent, the electrolyte being a magnesium salt; and the battery negative electrode comprising one of a metal, a metal alloy or a metal composite conductive material or Several.

Preferably, the metal, metal alloy or metal composite conductive material comprises magnesium metal, nickel, tin, zinc, lithium, aluminum, copper, bismuth, lead, antimony, bismuth, antimony, bismuth, antimony, cobalt, antimony, calcium. A composite of one or any one of ruthenium, gold, silver, iridium or an alloy of any one of them.

Preferably, the positive active material includes one or more of a graphite-based material, a sulfide, a nitride, an oxide, and a carbide having a layered crystal structure.

Preferably, the magnesium salt comprises one or more of an organic magnesium salt or an inorganic magnesium salt.

Preferably, the concentration of the magnesium salt ranges from 0.1 to 10 mol/L.

Preferably, the solvent comprises one or more of an ester, a sulfone, an ether, a nitrile organic solvent or an imidazole, a piperidine, a pyrrole, a quaternary ammonium, an amide ionic liquid.

Preferably, the solvent comprises propylene carbonate, ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, dibutyl carbonate, Butyl carbonate, methyl isopropyl carbonate, methyl ester, methyl formate, methyl acetate, N,N-dimethylacetamide, vinyl fluorocarbonate, methyl propionate, ethyl propionate, ethyl acetate Ester, γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxocyclopentane, 4-methyl-1,3-dioxocyclopentane, dimethoxymethane, 1,2- Dimethoxyethane, 1,2-dimethoxypropane, triethylene glycol dimethyl ether, dimethyl sulfone, acetonitrile, dimethyl ether, vinyl sulfite, propylene sulfite, dimethyl sulfite, Diethyl sulfite, crown ether, 1-ethyl-3-methylimidazole-hexafluorophosphate, 1-ethyl-3-methylimidazole-tetrafluoroborate, 1-ethyl-3-methyl Imidazole-bistrifluoromethylsulfonimide salt, 1-propyl-3-methylimidazolium-hexafluorophosphate, 1-propyl-3-methylimidazole-tetrafluoroborate, 1- Propyl-3-methylimidazole-bistrifluoromethylsulfonimide salt, 1-butyl-1-methylimidazole-hexafluorophosphate, 1-butyl-1-methylimidazole-tetrafluoroboron Acid salt, 1-butyl-1-methylimidazole-bistrifluoromethylsulfonimide salt, N-butyl-N-methylpyrrolidine-bistrifluoromethylsulfonimide salt, 1- Butyl-1-methylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl-N-propylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl, propyl One or more of piperidine-bistrifluoromethylsulfonimide salt, N-methyl, butylpiperidine-bistrifluoromethylsulfonimide salt.

In a second aspect, the present invention also provides a method for preparing a secondary battery, the method comprising:

A battery negative electrode is prepared, and a metal, metal alloy or metal composite conductive material of a desired size is subjected to surface treatment and used as a battery negative electrode.

The electrolyte is prepared, and a certain amount of magnesium salt electrolyte is added to the corresponding solvent, and stirred and dissolved.

A separator is prepared, and a porous polymer film or an inorganic porous film or an organic/inorganic composite separator of a desired size is used as a battery separator.

Prepare the positive electrode of the battery, weigh the living active material, the conductive agent and the binder according to a certain ratio, and fully grind into a uniform slurry to form a positive active material layer; and use the metal, metal alloy or metal composite conductive material as A cathode current collector; the cathode active material layer is then uniformly applied to the surface of the cathode current collector, and the battery anode of a desired size is obtained after the cathode active material layer is completely dried.

The battery anode, the electrolyte, the separator, and the battery positive electrode were assembled.

Compared with the prior art, the present invention has the beneficial effects that the present invention provides a secondary battery, which uses magnesium salt as an electrolyte, and solves the problem of limited lithium resource storage; and the battery negative electrode of the secondary battery provided by the present invention. At the same time, it functions as a material for reacting with the cation in the electrolyte, and the negative electrode of the secondary battery in the prior art generally includes a current collector for conducting electricity and an active material for reacting, saving the volume of one part and Weight, thus significantly reducing the weight and volume of the battery, increasing the energy density of the battery; compared to the prior art magnesium ion battery using magnesium salt as the electrolyte, the negative electrode of the present invention uses magnesium in addition to magnesium metal or alloy material. Other gold in which alloying occurs The genus or alloy material or composite increases the selectivity of the negative electrode material; at the same time, the electrochemical process involved in the secondary battery of the present invention is a double ion reaction, one end of the positive electrode is an anion intercalation reaction, and one end of the negative electrode is a deposition or alloying of magnesium ions. The reaction avoids the problem of difficulty in the extraction and embedding of the positive electrode active material magnesium ions in the magnesium ion battery in the prior art.

DRAWINGS

FIG. 1 is a schematic structural view of a secondary battery according to an embodiment of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments. The following are the preferred embodiments of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the embodiments of the present invention. It is also considered to be the scope of protection of the present invention.

The present invention provides a secondary battery having a structure as shown in FIG. 1, comprising a battery negative electrode 1, an electrolyte 2, a separator 3, and a battery positive electrode 4, wherein the battery positive electrode includes a positive electrode current collector 42 and a positive electrode active material layer 41. The positive active material layer includes a positive active material having a layered crystal structure; the electrolyte includes an electrolyte and a solvent, the electrolyte is a magnesium salt; and the battery negative electrode includes a metal, a metal alloy or a metal One or more of the composite conductive materials.

In an embodiment of the invention, the magnesium salt contained in the electrolyte is dissociated into an anion and a magnesium ion; when charging the secondary battery of the embodiment of the invention, an external electric field is applied between the battery negative electrode and the positive electrode current collector, when the battery is negative When an alloy of magnesium or magnesium is used as a composite of magnesium or magnesium, the magnesium ions in the electrolyte are deposited on the negative electrode of the battery under the action of an electric field to form a simple substance of magnesium. When the negative electrode of the battery is other metals or alloys or composites, the electrolyte is in the electrolyte. The magnesium ions are deposited on the negative electrode of the battery under the action of an electric field to form a cathode Gold, an anion in the electrolyte is embedded in the positive electrode active material under the action of an electric field; when the secondary battery of the embodiment of the invention is discharged, the magnesium ion is released from the elemental substance of the magnesium or the alloy formed with the negative electrode, and is returned to the electrolyte. The anion embedded in the positive electrode active material also escapes back into the electrolyte; thereby achieving reversible charge and discharge.

The battery negative electrode in the secondary battery of the embodiment of the present invention simultaneously functions as a conductive material and reacts with a cation in the electrolyte, and the negative electrode of the secondary battery in the prior art generally includes a current collecting current and is used for occurrence. The reactive material of the reaction saves the volume and weight of one component, thus significantly reducing the weight and volume of the battery and increasing the energy density of the battery.

The electrochemical process involved in the secondary battery of the present invention is a double ion reaction, one end of the positive electrode is an anion intercalation reaction, and one end of the negative electrode is a deposition or alloying reaction of magnesium ions, thereby avoiding the magnesium ion of the positive electrode active material in the magnesium ion battery in the prior art. The problem of getting out and embedding is difficult.

In a preferred embodiment of the present invention, the metal, metal alloy or metal composite conductive material includes, but is not limited to, magnesium metal, nickel, tin, zinc, lithium, aluminum, copper, bismuth, lead, antimony, bismuth, antimony, a composite of yttrium, lanthanum, cobalt, lanthanum, calcium, lanthanum, gold, silver, cerium or any one of them or an alloy of any one thereof, as long as the metal can be reversibly deposited to dissolve magnesium or with magnesium It is sufficient to form an alloy, and the present invention does not limit the kind of metal.

Compared with the magnesium ion battery using the magnesium salt as the electrolyte in the prior art, the negative electrode of the present invention uses other metal or alloy materials or composites which can be alloyed with magnesium in addition to the magnesium metal or alloy material to increase the negative electrode. The selectivity of the material.

In a preferred embodiment of the present invention, the cathode current collector includes, but is not limited to, one of aluminum, lithium, magnesium, vanadium, copper, iron, tin, zinc, nickel, titanium, manganese, or any one of them. A composite or an alloy of any of them.

In an embodiment of the invention, the positive active material layer further includes a conductive agent and a binder.

In a preferred embodiment of the present invention, the positive electrode active material layer comprises 60 to 90% by weight of the positive electrode active material by weight percentage.

In a preferred embodiment of the present invention, the positive electrode active material layer comprises 0.1 to 30% by weight of a conductive agent in percentage by weight.

In a preferred embodiment of the present invention, the positive electrode active material layer comprises 0.1 to 10% by weight of a binder by weight.

It is to be understood that the positive electrode active material in the positive electrode active layer is also not particularly limited as long as it has a layered crystal structure, and can reversibly desorb or embed an anion which is dissociated from the magnesium salt; the positive electrode active material layer The binder and the conductive agent are also not particularly limited, and are conventionally used in the art.

In a preferred embodiment of the present invention, the positive active material includes, but is not limited to, one or more of a graphite-based material, a sulfide, a nitride, an oxide, and a carbide having a layered crystal structure.

In a preferred embodiment of the invention, the graphite-based material includes, but is not limited to, natural graphite, artificial graphite or graphite flakes.

In a preferred embodiment of the invention, the sulfide includes, but is not limited to, molybdenum disulfide, tungsten disulfide or vanadium disulfide.

In a preferred embodiment of the invention, the nitride includes, but is not limited to, hexagonal boron nitride or carbon doped hexagonal boron nitride.

In a preferred embodiment of the invention, the oxide includes, but is not limited to, molybdenum trioxide, tungsten trioxide or vanadium pentoxide.

In a preferred embodiment of the invention, the carbide includes, but is not limited to, titanium carbide, tantalum carbide or molybdenum carbide.

In a preferred embodiment of the present invention, the conductive agent is conductive acetylene black, conductive carbon ball, and conductive One or more of graphite, carbon nanotubes, and graphene.

In a preferred embodiment of the present invention, the binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, styrene butadiene rubber, and polyolefin.

In the embodiment of the invention, the electrolyte is a magnesium salt, and one or more of an organic magnesium salt or an inorganic magnesium salt.

In a preferred embodiment of the invention, the magnesium salt has a concentration ranging from 0.1 to 10 mol/L.

In a preferred embodiment of the present invention, the organic magnesium salt includes, but is not limited to, RMgX, N-methylaniline magnesium bromide, pyrrolyl magnesium bromide, disodium magnesium edetate (EDTA-Mg), N,N-bis(trimethylsilyl)aminomagnesium chloride, Mg(SnPh ₃ ) ₂ , Mg(BR ₂ R' ₂ ) ₂ or Mg(AZ _3-n R _n' R'_n" ) type ₂ complex One or more of them, wherein R is an alkyl group, X is a halogen, A is Al, B, As, P, Sb, Ta or Fe, Z is Cl or Br, R' is an aryl group, and n'+n"=n.

In a preferred embodiment of the present invention, the inorganic magnesium salt includes, but is not limited to, Mg(ClO ₄ ) ₂ , Mg(BF ₄ ) ₂ , Mg(PF ₆ ) ₂ , MgCl ₂ , MgBr ₂ , MgF ₂ , MgI. ₂ , one or more of Mg(NO ₃ ) ₂ , MgSO ₄ , Mg(SCN) ₂ , MgCrO ₄ or Mg(CF ₃ SO ₃ ) ₂ .

It is to be understood that the solvent in the embodiment of the present invention is not particularly limited as long as the solvent can dissociate the electrolyte into cations and anions, and the cations and anions can freely migrate.

In a preferred embodiment of the present invention, the solvent includes, but is not limited to, an ester, a sulfone, an ether, a nitrile organic solvent or an imidazole, a piperidine, a pyrrole, a quaternary ammonium, an amide ionic liquid. One or several.

In a preferred embodiment of the invention, the solvent includes, but is not limited to, propylene carbonate, ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, carbonic acid. Methyl propyl ester, dibutyl carbonate, methyl butyl carbonate, methyl isopropyl carbonate, methyl ester, methyl formate, methyl acetate, N, N-dimethylacetamide, fluoroethylene carbonate, propionic acid Ester, ethyl propionate, ethyl acetate, Γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxocyclopentane, 4-methyl-1,3-dioxocyclopentane, dimethoxymethane, 1,2-dimethyl Oxyethane, 1,2-dimethoxypropane, triethylene glycol dimethyl ether, dimethyl sulfone, acetonitrile, dimethyl ether, vinyl sulfite, propylene sulfite, dimethyl sulfite, sulfurous acid Diethyl ester, crown ether, 1-ethyl-3-methylimidazole-hexafluorophosphate, 1-ethyl-3-methylimidazole-tetrafluoroborate, 1-ethyl-3-methylimidazole - bistrifluoromethylsulfonylimide salt, 1-propyl-3-methylimidazolium-hexafluorophosphate, 1-propyl-3-methylimidazole-tetrafluoroborate, 1-propyl- 3-methylimidazole-bistrifluoromethylsulfonimide salt, 1-butyl-1-methylimidazole-hexafluorophosphate, 1-butyl-1-methylimidazole-tetrafluoroborate, 1-butyl-1-methylimidazole-bistrifluoromethylsulfonimide salt, N-butyl-N-methylpyrrolidine-bistrifluoromethylsulfonimide salt, 1-butyl- 1-methylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl-N-propylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl, propyl piperidine- Bis-trifluoromethylsulfonimide salt, N-methyl, butyl piperidine-double One or more fluoromethyl sulfonimide salts.

In a preferred embodiment of the invention, the solvent is an ether. Compared with other kinds of solvents, ethers, especially the more polar ethers, do not form an oxide layer on the surface of the metal or metal alloy or metal composite of the negative electrode of the battery, which is beneficial to the deposition of magnesium ions in the negative electrode of the battery during charge and discharge. Come out.

Specifically, the ether solvent includes, but is not limited to, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2Me-THF), 1,3-dioxolane (DN), 1,4-dioxane, and One or more of diethyl ether (DEE), ethylene glycol dimethyl ether (DME) or tetraethylene glycol dimethyl ether.

In a preferred embodiment of the present invention, the electrolyte may be added with an additive such as LiCl. The additive functions to improve the ionic conductivity of the electrolyte or to improve the high and low temperature performance, safety performance, cycle performance and the like of the battery.

It is to be understood that the separator is also not particularly limited, and a conventionally used separator in the art may be employed.

In an embodiment of the invention, the separator includes, but is not limited to, an insulating porous polymer film or Inorganic porous film or organic/inorganic composite separator.

In a preferred embodiment of the invention, the separator includes, but is not limited to, a porous polypropylene film, a porous polyethylene film, a porous composite polymer film, a nonwoven fabric, a glass fiber paper, or a porous ceramic separator.

In a preferred embodiment of the invention, the membrane is a glass fiber paper or a nonwoven fabric.

It is to be understood that the form of the secondary battery provided by the present invention is not particularly limited, and may be commonly used in the art, such as a button battery, a flat battery, a cylindrical battery, and the like.

In a second aspect, the embodiment of the invention further provides a method for preparing the above secondary battery, comprising:

Step 101: Prepare a battery negative electrode, and subject the metal, metal alloy or metal composite conductive material of a desired size to a surface treatment to serve as a battery negative electrode.

Specifically, the metal, metal alloy or metal composite conductive material is selected from the group consisting of magnesium metal, nickel, tin, zinc, lithium, aluminum, copper, bismuth, lead, antimony, bismuth, antimony, bismuth, antimony, cobalt, antimony, calcium, A composite of one of or one of ruthenium, gold, silver, iridium or an alloy of any one of them.

Step 102: Prepare an electrolyte solution, add a certain amount of magnesium salt electrolyte to the corresponding solvent, and fully stir and dissolve.

The magnesium salt electrolyte specifically includes one or more of an organic magnesium salt and an inorganic magnesium salt.

Specifically, the organic magnesium salt includes, but is not limited to, RMgX, N-methylaniline magnesium bromide, pyrrolyl magnesium bromide, N,N-bis(trimethylsilyl)aminomagnesium chloride, ethylenediamine four One of magnesium diacetate acetate (EDTA-Mg), Mg(SnPh ₃ ) ₂ , Mg(BR ₂ R' ₂ ) ₂ , Mg(AZ _3-n R _n' R'_n" ) type ₂ complex or Wherein R is an alkyl group, X is a halogen, A is Al, B, As, P, Sb, Ta or Fe, Z is Cl or Br, R' is an aryl group, and n'+n"=n .

Specifically, the inorganic magnesium salt includes, but is not limited to, Mg(ClO ₄ ) ₂ , Mg(BF ₄ ) ₂ , Mg(PF ₆ ) ₂ , MgCl ₂ , MgBr ₂ , MgF ₂ , MgI ₂ , Mg (NO). ₃ ) One or more of ₂ , MgSO ₄ , Mg(SCN) ₂ , MgCrO ₄ , Mg(CF ₃ SO ₃ ) ₂ .

Specifically, the magnesium salt is obtained by direct purchase or by reacting two solutions together.

The solvent includes, but is not limited to, one or more of an ester, a sulfone, an ether, a nitrile organic solvent or an imidazole, a piperidine, a pyrrole, a quaternary ammonium, an amide ionic liquid, and is selected from the group consisting of carbonic acid. Propylene ester, ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, dibutyl carbonate, methylbutyl carbonate, methyl carbonate Propyl ester, methyl ester, methyl formate, methyl acetate, N,N-dimethylacetamide, fluoroethylene carbonate, methyl propionate, ethyl propionate, ethyl acetate, γ-butyrolactone, Tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxocyclopentane, 4-methyl-1,3-dioxocyclopentane, dimethoxymethane, 1,2-dimethoxyethane, 1, 2-Dimethoxypropane, triethylene glycol dimethyl ether, dimethyl sulfone, acetonitrile, dimethyl ether, vinyl sulfite, propylene sulfite, dimethyl sulfite, diethyl sulfite, crown ether , 1-ethyl-3-methylimidazolium-hexafluorophosphate, 1-ethyl-3-methylimidazole-tetrafluoroborate, 1-ethyl-3-methylimidazole-bistrifluoromethyl Sulfoimide salt, 1-propyl-3-methylimidazole-six Phosphate, 1-propyl-3-methylimidazole-tetrafluoroborate, 1-propyl-3-methylimidazole-bistrifluoromethylsulfonimide salt, 1-butyl-1-methyl Imidazolium-hexafluorophosphate, 1-butyl-1-methylimidazole-tetrafluoroborate, 1-butyl-1-methylimidazole-bistrifluoromethylsulfonimide salt, N-butyl -N-methylpyrrolidine-bistrifluoromethylsulfonimide salt, 1-butyl-1-methylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl-N- Propyl pyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl, propyl piperidine-bistrifluoromethylsulfonimide salt, N-methyl, butyl piperidine-bistrifluoromethyl One or more of the sulfonylimide salts.

The magnesium salt is added to the solvent and dissolved sufficiently with stirring, and the concentration of the magnesium salt in the disposed electrolyte is in the range of 0.1 to 10 mol/L.

Step 103: Prepare a separator, and use a porous polymer film or an inorganic porous film or an organic/inorganic composite separator of a desired size as a battery separator.

Specifically, the porous polymer film or inorganic porous film includes, but is not limited to, porous polypropylene Film, porous polyethylene film, porous composite polymer film, glass fiber paper or porous ceramic separator.

Step 104: preparing a positive electrode of the battery, weighing a living active material, a conductive agent and a binder according to a certain ratio, adding a suitable slurry to a uniform slurry to form a positive active material layer; and forming a metal, a metal alloy or a metal composite The conductive material is used as a positive electrode current collector; the positive electrode active material layer is then uniformly applied to the surface of the positive electrode current collector, and the positive electrode active material layer is completely dried to obtain a battery positive electrode of a desired size.

The positive current collector positive current collector is a metal, metal alloy or metal composite conductive material, and may be selected from one of aluminum, magnesium, vanadium, lithium, copper, iron, tin, zinc, nickel, titanium, manganese or any one of them. A metal composite or an alloy of any of them.

The amount of the positive electrode active material in the positive electrode active material layer is 60 to 90% by weight, the content of the conductive agent is 0.1 to 30% by weight, and the content of the binder is 0.1 to 10% by weight.

The positive active material includes, but is not limited to, one or more of a graphite-based material, a sulfide, a nitride, an oxide, and a carbide having a layered crystal structure.

The conductive agent includes, but is not limited to, one or more of conductive acetylene black, conductive carbon spheres, conductive graphite, carbon nanotubes, and graphene.

The binder includes, but is not limited to, one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, styrene butadiene rubber, and polyolefin.

Step 105: assembling using the battery negative electrode, the electrolyte solution, the separator, and the battery positive electrode.

Specifically, the prepared negative electrode, the separator and the positive electrode of the battery are closely stacked in an inert gas or an anhydrous oxygen-free environment, and the electrolyte is dripped to completely infiltrate the separator, and then packaged into the battery case to complete the battery assembly.

It should be noted that although the above steps 101-104 describe the operation of the preparation method of the present invention in a specific order, it is not required or implied that these operations must be performed in this particular order. Step The preparation of steps 101-104 can be performed simultaneously or in any order.

The secondary battery preparation method and the foregoing secondary battery are based on the same inventive concept, and the secondary battery obtained by the secondary battery preparation method has all the effects of the foregoing secondary battery, and details are not described herein again.

The above secondary battery preparation method will be further described below by way of specific examples, but it should be understood that these examples are for the purpose of illustration only, and are not intended to limit the invention in any way.

Example 1

Preparation of battery negative electrode: Take a magnesium foil with a thickness of 0.02 mm, cut into a disk having a diameter of 12 mm, and use it as a negative electrode current collector after surface treatment.

Preparation of the separator: The Celgard 2400 porous polymer film was cut into a 16 mm diameter disc as a separator.

The electrolyte was prepared by mixing 2.5 ml of MgBu ₂ solution with 2.5 ml of AlCl ₂ Et solution, and then distilling off the solvent, and adding the reaction product Mg(AlCl ₂ BuEt) ₂ to a suitable high-purity tetrahydrofuran solution as an electrolyte.

Preparation of battery positive electrode: 0.8g artificial graphite, 0.1g carbon black, 0.1g polyvinylidene fluoride was added to 2ml of nitromethylpyrrolidone solution, fully ground to obtain a uniform slurry; then the slurry was uniformly applied to the surface of the aluminum foil (ie The cathode current collector) was dried under vacuum. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Battery assembly: In the inert gas-protected glove box, the prepared negative electrode current collector, separator, and battery positive electrode are closely stacked in sequence, and the electrolyte is dripped to completely infiltrate the separator, and then the stacked portion is packaged into the button battery case. , complete battery assembly.

Example 2

Preparation of battery negative electrode: Take a nickel foil with a thickness of 0.02 mm, cut into a 12 mm diameter disk, and use as a negative electrode current collector after surface treatment.

Preparation of the separator: The glass fiber paper was cut into a 16 mm diameter disc as a separator.

The electrolyte was prepared by mixing 2.5 ml of a MgEt ₂ solution with 2.5 ml of an AlCl ₂ Et solution, and then distilling off the solvent, and adding the reaction product Mg(AlCl ₂ Et ₂ ) ₂ to an appropriate high-purity tetrahydrofuran solution as an electrolyte.

Preparation of battery positive electrode: 0.7g hard carbon, 0.2g carbon black, 0.1g polyvinylidene fluoride was added to 2ml of nitromethylpyrrolidone solution, fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the surface of the aluminum foil and vacuum dry. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Example 3

Preparation of battery negative electrode: Take a zinc foil with a thickness of 0.02 mm, cut into a 12 mm diameter disc, and use it as a negative electrode current collector after surface treatment.

The electrolyte was prepared: 2.5 ml of the MgPh ₂ solution was mixed with 2.5 ml of the AlCl ₂ Et solution, and then the solvent was distilled off, and the reaction product Mg (AlCl ₂ PhEt) _{2 was} added to a suitable high-purity tetrahydrofuran solution as an electrolyte for use.

Preparation of battery positive electrode: 0.8g carbon microspheres, 0.15g carbon black, 0.05g polyvinylidene fluoride was added to 2ml of nitromethylpyrrolidone solution, fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the surface of the aluminum foil and Dry in vacuum. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Example 4

Preparation of battery negative electrode: Take a tin foil with a thickness of 0.02 mm, cut into a 12 mm diameter disc, and use as a negative electrode current collector after surface treatment.

Prepare the electrolyte: Mix 2.5 ml of MgBu ₂ solution with 2.5 ml of AlCl ₃ solution, then distill the solvent out, and add the reaction product Mg(AlCl ₃ Bu) ₂ to the appropriate high-purity tetraethylene glycol dimethyl ether solution. The electrolyte is ready for use.

Preparation of battery positive electrode: 1g of titanium carbide, 0.15g of carbon black, 0.05g of polytetrafluoroethylene was added to 2ml of nitromethylpyrrolidone solution, fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the surface of the zinc foil and vacuum dry. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Example 5

Preparation of battery negative electrode: Take a copper foil with a thickness of 0.02 mm, cut into a disk having a diameter of 12 mm, and use it as a negative electrode current collector after surface treatment.

Preparation of a separator: A porous polypropylene film was cut into a disk having a diameter of 16 mm as a separator for use.

Prepare the electrolyte: Mix 2.5 ml of MgBu ₂ solution with 2.5 ml of BPh ₃ solution, then distill the solvent out, and add the reaction product Mg(BPh ₃ Bu) ₂ to the appropriate high purity ethylene glycol dimethyl ether (DME) solution. The electrolyte is ready for use.

Preparation of battery positive electrode: 1 g of molybdenum disulfide, 0.15 g of graphene, 0.05 g of polyvinylidene fluoride was added to 2 ml of nitromethylpyrrolidone solution, and fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the surface of the aluminum foil and vacuumed dry. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Example 6

Preparation of battery negative electrode: Take aluminum foil with a thickness of 0.02 mm, cut into a 12 mm diameter disc, and use as a negative electrode current collector after surface treatment.

Prepare the electrolyte: Mix 2.5 ml of MgBu ₂ solution and 2.5 ml of BCl ₃ solution, then distill off the solvent, and add the reaction product Mg(BCl ₃ Bu) ₂ to the appropriate high purity diethyl ether (DEE) solution as electrolyte. spare.

Preparation of battery positive electrode: 1 g of molybdenum disulfide, 0.15 g of Super P conductive carbon spheres, 0.05 g of polyvinyl alcohol was added to 2 ml of a solution of nitromethylpyrrolidone, and fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the copper foil. The surface was dried under vacuum. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Example 7

Preparation of battery negative electrode: Take a lithium foil with a thickness of 0.02 mm, cut into a 12 mm diameter disk, and use it as a negative electrode current collector after surface treatment.

Preparation of a separator: A porous polyethylene film was cut into a disk having a diameter of 16 mm as a separator for use.

Preparation of electrolyte: Weigh a certain amount of C ₃ H ₄ N ₂ MgBr dissolved in 1,4-dioxane, stir well and use as electrolyte.

Preparation of battery positive electrode: 0.8g hard carbon, 0.1g carbon black, 0.1g polyvinylidene fluoride was added to 2ml of nitromethylpyrrolidone solution, fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the surface of aluminum foil and vacuum dry. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Example 8

Preparation of electrolyte: Weigh a certain amount of C ₃ H ₈ NMgCl dissolved in 1,3-dioxolane (DN), stir well and use as electrolyte.

Preparation of battery positive electrode: 0.8g of hexagonal boron nitride, 0.1g of graphene, 0.1g of polyvinylidene fluoride was added to 2ml of nitromethylpyrrolidone solution, fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the surface of the aluminum foil And dried in a vacuum. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Example 9

Preparation of the separator: The porous polycomposite polymer film was cut into a 16 mm-diameter wafer as a separator for use.

Formulation of electrolyte: Weigh a certain amount of Mg(CF ₃ SO ₃ ) ₂ dissolved in a mixture of PP ₁₃ -TFSI and BMImBF ₄ with a volume ratio of 1:1, stir well and use as electrolyte.

Preparation of battery positive electrode: 0.8 g of titanium oxide, 0.1 g of conductive carbon fiber, 0.1 g of polyvinylidene fluoride was added to 2 ml of nitromethylpyrrolidone solution, and fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the surface of the aluminum foil and vacuumed dry. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Example 10

Preparation of the separator: The nonwoven fabric was cut into a 16 mm-diameter disc and used as a separator.

Preparation of electrolyte: Weigh a certain amount of Mg (SnPh ₃ ) ₂ dissolved in 2-methyltetrahydrofuran, stir well and use as electrolyte.

Preparation of battery positive electrode: 0.8 g zinc selenide, 0.1 g carbon black, 0.1 g polyvinylidene fluoride was added to 2 ml of nitromethylpyrrolidone solution, fully ground to obtain a uniform slurry; then the slurry was uniformly coated on the surface of the copper foil And dried in a vacuum. The electrode sheet obtained by drying was cut into a disk having a diameter of 10 mm, and compacted as a battery positive electrode.

Battery assembly: The prepared negative electrode current collector is separated in an inert gas-protected glove box. The membrane and the positive electrode of the battery are closely stacked in sequence, and the electrolyte is dripped to completely infiltrate the separator, and then the stacked portion is packaged into the button battery case to complete the battery assembly.

The form of the secondary battery according to the present invention is not limited to the button type battery, and may be designed in the form of a flat battery or a cylindrical battery depending on the core component.

The main active component of the secondary battery proposed by the invention has a layered crystal structure and is placed in a material, is environmentally friendly and low in cost, and avoids the difficulty of inserting magnesium ions into the positive electrode material, and has better electricity than ordinary magnesium ion batteries. Chemical properties.

The above described specific embodiments of the present invention are further described in detail, and are intended to be illustrative of the embodiments of the present invention. All modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

A secondary battery comprising a battery negative electrode, an electrolyte, a separator, and a battery positive electrode, wherein

The battery negative electrode includes one or more of a metal, a metal alloy or a metal composite conductive material;

The electrolyte includes an electrolyte and a solvent, and the electrolyte is a magnesium salt;

The battery positive electrode includes a positive electrode current collector layer and a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode active material having a layered crystal structure.
The secondary battery according to claim 1, wherein said metal, metal alloy or metal composite conductive material comprises magnesium metal, nickel, tin, zinc, lithium, aluminum, copper, bismuth, lead, antimony, bismuth. A composite of one or a combination of any one of ruthenium, rhodium, iridium, cobalt, osmium, calcium, osmium, gold, silver, iridium, or any one of them.
The secondary battery according to claim 1, wherein the positive electrode active material comprises one or more of a graphite-based material, a sulfide, a nitride, an oxide, and a carbide having a layered crystal structure.
The secondary battery according to claim 1, wherein the magnesium salt comprises one or more of an organic magnesium salt or an inorganic magnesium salt.
The secondary battery according to claim 1, wherein the magnesium salt has a concentration ranging from 0.1 to 10 mol/L.
The secondary battery according to claim 1, wherein the solvent comprises an ester, a sulfone, an ether, a nitrile organic solvent or an imidazole, a piperidine, a pyrrole, a quaternary ammonium, an amide ion. One or several of the liquids.
The secondary battery according to claim 6, wherein said solvent comprises propylene carbonate, ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, and ethyl carbonate Ester, methyl propyl carbonate, dibutyl carbonate, methyl butyl carbonate, methyl isopropyl carbonate, methyl ester, methyl formate, methyl acetate, N, N-dimethylacetamide, vinyl fluorocarbonate, Methyl propionate, ethyl propionate, ethyl acetate, γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxocyclopentane, 4-methyl-1,3-dioxane Pentane, dimethoxymethane, 1,2-dimethoxyethane, 1,2-dimethoxypropane, triethylene glycol dimethyl ether, dimethyl sulfone, acetonitrile, dimethyl ether, vinyl sulfite , propylene sulfite, dimethyl sulfite, diethyl sulfite, crown ether, 1-ethyl-3-methylimidazole-hexafluorophosphate, 1-ethyl-3-methylimidazole-tetrafluoro Borate, 1-ethyl-3-methylimidazole-bistrifluoromethylsulfonimide salt, 1-propyl-3-methylimidazole-hexafluorophosphate, 1-propyl-3-methyl Imidazole-tetrafluoroborate, 1-propyl-3-methylimidazole-bistrifluoromethylsulfonimide salt, 1-butyl-1-methylimidazole-hexafluorophosphate, 1-butyl 1-methylimidazole-tetrafluoroborate, 1-butyl-1-methylimidazole-bistrifluoromethylsulfonimide salt, N-butyl-N-methylpyrrolidine-double Fluoromethyl Imide salt, 1-butyl-1-methylpyrrolidine-bistrifluoromethylsulfonimide salt, N-methyl-N-propylpyrrolidine-bistrifluoromethylsulfonimide salt One or more of N-methyl, propyl piperidine-bistrifluoromethylsulfonimide salt, N-methyl, butyl piperidine-bistrifluoromethylsulfonimide salt.
A method for preparing a secondary battery according to any one of claims 1 to 7, characterized in that it comprises:

Preparing a battery negative electrode, and subjecting the metal, metal alloy or metal composite conductive material of a desired size to a surface treatment to serve as a battery negative electrode;

Preparing an electrolyte, adding a certain amount of magnesium salt electrolyte to the solvent, and stirring and dissolving;

Preparing a separator, using a porous polymer film or an inorganic porous film or an organic/inorganic composite separator of a desired size as a battery separator;

Prepare the positive electrode of the battery, weigh the living active material, the conductive agent and the binder according to a certain ratio, and fully grind into a uniform slurry to form a positive active material layer; and use the metal, metal alloy or metal composite conductive material as a cathode current collector; then uniformly coating the cathode active material layer on a positive current collector surface, after the cathode active material layer is completely dried, and then cut to obtain a battery positive electrode of a desired size;

The battery anode, the electrolyte, the separator, and the battery positive electrode were assembled.