CN105742727B - A kind of preparation method of secondary cell, purposes and its cathode - Google Patents

Abstract

The invention discloses a secondary battery, its use and a preparation method for its negative electrode. The secondary battery includes solid metal sodium or lithium or potassium, conductive liquid metal, solid electrolyte, positive electrode material and battery case; the solid state The metal sodium or lithium or potassium and the conductive liquid metal are accommodated in the solid electrolyte tube formed by the solid electrolyte, or the solid metal sodium or lithium or potassium and the conductive liquid metal are filled in the battery shell Between the body and the solid electrolyte, the solid metal sodium or lithium or potassium together with the conductive liquid metal constitute the high-capacity negative electrode of the secondary battery; the positive electrode material is filled between the battery case and the solid Between the electrolytes, the positive electrode of the secondary battery is formed, wherein the conductive liquid metal includes a liquid formed by mixing any one or more of metal sodium, lithium, and potassium with aromatic compounds and ether solvents.

Description

A kind of secondary battery, application and preparation method of negative electrode thereof

technical field

The invention relates to the technical field of batteries, in particular to a secondary battery, its use and a preparation method for its negative electrode.

Background technique

With the depletion of traditional fossil energy and the increasingly prominent environmental problems, it is imminent to develop and utilize renewable energy such as solar energy and wind energy. However, due to the instability and intermittency of solar and wind energy, the power grid is unstable, so it is necessary to vigorously develop large-scale energy storage technology. Large-scale energy storage technology can effectively solve the problem of intermittent power supply from renewable energy sources such as solar energy and wind energy, realize demand management, eliminate peak and valley differences between day and night, and smooth loads.

At present, the main large-scale energy storage technologies include pumped hydro storage, compressed air energy storage, flywheel energy storage, electrochemical energy storage, etc. Various energy storage technologies have their own conditions of use and advantages, and are in the active research and development and demonstration stages. Among them, chemical power sources for energy storage, such as sodium-sulfur batteries, all-vanadium redox flow batteries, and lithium-ion batteries, have been demonstrated as large-scale energy storage devices.

However, sodium-sulfur batteries need to operate at a high temperature of 300 degrees, and the direct use of molten metal sodium and sulfur has led to serious corrosion problems and potential safety hazards in this battery. The vanadium ions used in the all-vanadium redox flow battery are highly toxic substances and have limited resources. In addition, there is a problem of interdiffusion of positive and negative active materials during its operation, and the energy density of this energy storage battery is not high. Lithium-ion batteries have good performance as large-scale energy storage batteries, but the manufacturing cost of lithium-ion energy storage batteries is high. Therefore, there is currently no energy storage battery that can meet the comprehensive requirements of low cost, good safety, and abundant raw materials. Metal sodium or lithium-based batteries have the advantage of high energy density, but metal sodium or lithium will have dendrites and side reactions when charging and discharging in organic electrolyte batteries. Here we propose a method that can overcome dendrite growth. , side reactions, and room-temperature battery design to achieve high energy densities for metal batteries.

Contents of the invention

The embodiment of the present invention provides a new type of secondary battery, its application and its negative electrode preparation method. By placing solid metal sodium or lithium or potassium in the conductive liquid metal negative electrode, the capacity of the conductive liquid metal negative electrode is greatly improved, thereby increasing the energy density of the battery, and it also solves the problem between the solid metal negative electrode and the solid electrolyte. The problems of high interface resistance, dendrite growth and side reactions. The secondary battery of the invention has the characteristics of high specific energy and long cycle life, and can be used for storing output electric energy of power stations such as solar energy and wind energy.

In the first aspect, an embodiment of the present invention provides a secondary battery, the secondary battery includes solid metal sodium or lithium or potassium, conductive liquid metal, solid electrolyte, positive electrode material and battery case;

The solid metal sodium or lithium or potassium and the conductive liquid metal are accommodated in the solid electrolyte tube, or the solid metal sodium or lithium or potassium and the conductive liquid metal are filled in the battery case Between the solid electrolyte, the solid metal sodium or lithium or potassium together with the conductive liquid metal constitute the negative electrode of the secondary battery;

The conductive liquid metal includes a liquid formed by mixing any one or more of metal sodium, lithium, and potassium with aromatic compounds and ether solvents;

The positive electrode material is filled between the battery case and the solid electrolyte to form the positive electrode of the secondary battery;

Wherein, the positive electrode material includes polysulfide ion solution, anthraquinone solution, benzoquinone solution, iodine solution, benzophenone solution, tetramethoxy piperidine oxide TEMPO solution, or Na _0.44 MnO ₂ , NaTi ₂ (PO ₄ ) ₃ , Na ₃ V ₂ (PO ₄ ) ₃ , Na _0.8 Li _0.1 Ni _0.25 Mn _0.65 O ₂ , NaMg _0.1 Ni _0.4 Mn _0.2 Ti _0.3 O ₂ , S slurry composed of any one or more of carbon powder .

Preferably, the secondary battery is a cylindrical battery;

The solid electrolyte is tubular and housed in the battery case;

The solid metal sodium or lithium or potassium is accommodated in the solid electrolyte tube, and the conductive liquid metal is filled between the metal sodium or lithium or potassium and the solid electrolyte.

Preferably, the secondary battery is a dual-flow battery, and the battery further includes: a positive electrode liquid storage tank, a negative electrode liquid storage tank, and two pumps;

The solid electrolyte is a diaphragm, which separates the battery case into a closed positive electrode space and a negative electrode space, wherein the positive electrode space is connected to the positive electrode liquid storage tank, and all the positive electrode liquid stored in the positive electrode liquid storage tank is pumped The positive electrode material is pumped into the positive electrode space; the negative electrode space is connected to the negative electrode liquid storage tank, and the negative electrode liquid storage tank accommodates solid metal sodium or lithium or potassium and the conductive liquid metal, through a The pump pumps the conductive liquid metal accommodated in the negative electrode liquid storage tank into the negative electrode space.

Preferably, the secondary battery is a single flow battery, and the battery further includes: a positive electrode storage tank and a pump;

The solid electrolyte is a diaphragm, which separates the battery casing into a closed positive electrode space and a negative electrode space, wherein the positive electrode space is connected to the positive electrode liquid storage tank, and the positive electrode liquid contained in the positive electrode liquid storage tank is pumped The positive electrode material is pumped into the positive electrode space, and the negative electrode space is used to accommodate the solid metal sodium or lithium or potassium and the conductive liquid metal.

Preferably, the secondary battery is a flat battery;

The solid electrolyte is a separator, which separates the battery casing into a closed positive electrode space and a negative electrode space, the positive electrode space is used to accommodate the positive electrode material, and the negative electrode space is used to accommodate the solid metal sodium Or lithium or potassium and the conductive liquid metal material.

Preferably, the aromatic compound is any one or more of biphenyl, biphenyl derivatives, naphthalene, naphthalene derivatives, anthracene or anthracene derivatives;

The ether solvents include diethyl ether, methyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropyl ether, diisopropyl ether, ethyl butyl ether, diethylene glycol dimethyl ether, Butyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, di Methoxymethane, 1,2-dimethoxypropane, dioxolane, 1,4-dioxane, ethylene oxide, propylene oxide, 1,1-diethoxyethane Any one or more.

Preferably, the preparation method of the conductive liquid metal comprises:

In a protective atmosphere of argon, the alkali metal and the aromatic compound are added into an ether solvent according to a certain molar ratio, and left to stand to obtain the conductive liquid metal negative electrode material;

Wherein, the alkali metal is any one or more of sodium metal, lithium metal or potassium metal;

The aromatic compound is any one or more of biphenyl, biphenyl derivatives, naphthalene, naphthalene derivatives, anthracene or anthracene derivatives;

The ether solvents include diethyl ether, methyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropyl ether, diisopropyl ether, ethyl butyl ether, diethylene glycol dimethyl ether, Butyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, di Methoxymethane, 1,2-dimethoxypropane, dioxolane, 1,4-dioxane, ethylene oxide, propylene oxide, 1,1-diethoxyethane Any one or more.

Preferably, the preparation method of the high-capacity negative electrode comprises:

In the protective atmosphere of argon, inject the above-mentioned conductive liquid metal into the solid electrolyte tube, then put excess solid metal sodium or lithium or potassium into the conductive liquid metal, and then draw the negative electrode lead from the solid metal, and put the solid electrolyte tube The high-capacity negative electrode can be obtained after standing for two hours after the mouth is sealed;

Preferably, the solid electrolyte includes Na ₃ Zr ₂ Si ₂ PO ₁₂ ceramics, Na _- β″-Al ₂ O 3 ceramics, K-β″-Al ₂ O ₃ ceramics for conducting sodium ions, lithium ions or potassium ions Any one of ceramics, Li ₇ La ₃ Zr ₂ O ₁₂ ceramics or Li ₁₀ GeP ₂ S ₁₂ ceramics.

In the second aspect, the embodiment of the present invention provides a use of the secondary battery described in the first aspect above, and the secondary battery is used for solar power generation, wind power generation, smart grid peak regulation, distributed power station, backup power supply or communication Large-scale energy storage equipment for base stations.

In a third aspect, an embodiment of the present invention provides a method for preparing a negative electrode of a secondary battery described in the first aspect above, comprising:

In a protective atmosphere of argon, the conductive liquid metal is injected into the solid electrolyte tube formed by the solid electrolyte, or injected between the battery casing and the solid electrolyte;

placing an excess of solid metal sodium or lithium or potassium into a conductive liquid metal;

Draw the negative lead from the solid metal;

After sealing the nozzle of the solid electrolyte and standing still for two hours, the negative electrode was obtained.

The secondary battery provided by the embodiment of the present invention puts solid metal sodium, lithium or potassium in the conductive liquid metal negative electrode, which greatly improves the energy density of the conductive liquid metal battery, has high safety and low cost, and can Work in the temperature range from room temperature to 150°C. The material resource that can be applied to the preparation of the secondary battery of the present invention is abundant, the specific energy of the battery is high, and the cycle life is long, and it can be used for storing output electric energy of power stations such as solar energy and wind energy.

Description of drawings

The technical solutions of the embodiments of the present invention will be further described in detail below with reference to the drawings and embodiments.

Fig. 1 is a schematic structural diagram of a cylindrical battery provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a dual flow battery provided by an embodiment of the present invention;

Fig. 3 is a schematic structural diagram of a single flow battery provided by an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of a flat battery provided by an embodiment of the present invention;

Fig. 5 is the charging and discharging performance curve of the symmetrical battery composed of conductive liquid metal provided by the embodiment of the present invention;

Fig. 6 is the charging and discharging performance curve of the metal sodium immersed in the conductive liquid metal symmetric battery provided by the embodiment of the present invention;

Fig. 7 is the electrochemical impedance spectrum after charging and discharging the metal sodium immersed in the conductive liquid metal symmetric battery provided by the embodiment of the present invention;

Fig. 8 is the Raman spectrum of the metal sodium surface and the conductive liquid metal after metal sodium is immersed in the conductive liquid metal provided by the embodiment of the present invention;

FIG. 9 is a battery charge and discharge performance diagram of the secondary battery provided by the embodiment of the present invention.

Figure 10 is a charge and discharge performance diagram of a battery composed of solid metal sodium, conductive liquid metal, solid electrolyte, tetramethoxypiperidine oxide TEMPO liquid positive electrode material provided by the embodiment of the present invention;

Fig. 11 is a charge and discharge performance diagram of a battery composed of solid metal sodium, conductive liquid metal, solid electrolyte, and Na ₂ S ₈ liquid positive electrode material at 70°C provided by the embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the examples, but it is not intended to limit the protection scope of the present invention.

Example 1

This embodiment is used to illustrate the structure of the secondary battery provided by the present invention.

The secondary battery provided by the present invention includes solid metal sodium or lithium or potassium, conductive liquid metal, solid electrolyte, positive electrode material and battery case:

The solid metal sodium or lithium or potassium and the conductive liquid metal are housed in the solid electrolyte, or the solid metal sodium or lithium or potassium and the conductive liquid metal are filled in the battery case Between the solid electrolyte; the solid metal sodium or lithium or potassium together with the conductive liquid metal constitute the negative electrode of the secondary battery; this negative electrode design has a higher capacity than only using the conductive liquid metal as the negative electrode. The energy density of the battery is greatly improved; at the same time, placing the solid metal sodium in the conductive liquid metal can make the conductive liquid metal maintain a higher conductivity; in addition, placing the solid metal sodium or lithium or potassium in the conductive liquid metal also solves the problem. The problem of side reactions and dendrite growth of alkali metals in general organic solvents is solved.

The positive electrode material is filled between the battery case and the solid electrolyte to form the positive electrode of the secondary battery;

Wherein, the positive electrode material includes polysulfide ion solution, anthraquinone solution, benzoquinone solution, iodine solution, benzophenone solution, tetramethoxy piperidine oxide solution or Na _0.44 MnO ₂ , NaTi ₂ (PO ₄ ) ₃ , Na ₃ V ₂ (PO ₄ ) ₃ , Na _0.8 Li _0.1 Ni _0.25 Mn _0.65 O ₂ , NaMg _0.1 Ni _0.4 Mn _0.2 Ti _0.3 O ₂ , any one or more of S and carbon powder;

The conductive liquid metal includes a liquid formed by mixing any one or more of metal sodium, lithium, and potassium with aromatic compounds and ether solvents;

The aromatic compound is any one or more of biphenyl, biphenyl derivatives, naphthalene, naphthalene derivatives, anthracene or anthracene derivatives;

The ether solvents include diethyl ether, methyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropyl ether, diisopropyl ether, ethyl butyl ether, diethylene glycol dimethyl ether, Butyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, di Methoxymethane, 1,2-dimethoxypropane, dioxolane, 1,4-dioxane, ethylene oxide, propylene oxide, 1,1-diethoxyethane any one or more;

The solid electrolyte includes Na ₃ Zr ₂ Si ₂ PO ₁₂ ceramics, Na-β″-Al ₂ O ₃ ceramics, K-β″-Al ₂ O ₃ ceramics, Li Any one of ₇ La ₃ Zr ₂ O ₁₂ ceramics or Li ₁₀ GeP ₂ S ₁₂ ceramics.

The specific structure of the secondary battery of the present invention can be various, such as a cylindrical battery, a double flow battery, a single flow battery, or a flat battery, and the structural features of these different structures will be described with multiple embodiments later.

The working principle of the secondary battery of the present invention will be described below by taking metal sodium placed in a solid electrolyte tube containing conductive liquid metal to form the negative electrode of the secondary battery as an example.

When the secondary battery is discharged, the conductive liquid metal at the negative electrode loses electrons and is oxidized to biphenyl (Formula 1), and the electrons reach the positive electrode from the external circuit to reduce the positive electrode material; the sodium ions in the conductive liquid metal at the negative electrode pass through the solid electrolyte to reach the positive electrode and then To maintain charge balance, when the conductive liquid metal is oxidized to biphenyl, the solid metal sodium reduces it again (Formula 2), and the discharge process continues until the metal sodium is completely consumed. The entire discharge process will not end. The following is the reaction equation of the discharge process:

The charging process is opposite to the discharging process. The electrons go from the positive electrode to the negative electrode, and at the same time, the ions also pass from the positive electrode to the negative electrode through the solid electrolyte to reduce the biphenyl. When the sodium ions in the conductive liquid metal reach saturation, the sodium ions in the conductive liquid metal continue to be reduced to solid metal sodium, which is deposited on the current collector or the battery case.

The secondary battery of the present invention can work in the temperature range from room temperature to 150°C. This structural design improves the capacity of the conductive liquid metal negative electrode. At the same time, the design of the conductive liquid metal filled between the metal sodium and the solid electrolyte solves the problem of The interface resistance between the solid metal negative electrode and the solid electrolyte is very large, and the alkali metal has the problems of dendrite growth and side reactions.

Example 2

This example is used to illustrate the structure of the cylindrical battery described in Example 1 above.

Figure 1 is a schematic diagram of the structure of a cylindrical battery. As shown in Figure 1, a cylindrical battery can include: solid metal sodium or lithium or potassium, conductive liquid metal, battery casing, positive electrode material and solid electrolyte tube;

The solid electrolyte tube is nested in the battery casing without contact, and the closed space between the inner wall of the battery casing and the outer wall of the solid electrolyte tube is used to accommodate the positive electrode material; The negative electrode material composed of the conductive liquid metal and solid metal sodium or lithium or potassium is accommodated.

When the secondary battery is discharged, the conductive liquid metal at the negative electrode loses electrons and is oxidized to biphenyl (Formula 1), and the electrons reach the positive electrode from the external circuit to reduce the positive electrode material; the sodium ions in the conductive liquid metal at the negative electrode pass through the solid electrolyte to reach the positive electrode and then To maintain charge balance, when the conductive liquid metal is oxidized to biphenyl, the solid metal sodium reduces it again (Formula 2), and the discharge process continues until the metal sodium is completely consumed. The entire discharge process will not end. The charging process is opposite to the discharging process. Electrons go from the positive electrode to the negative electrode, and at the same time, the ions also pass from the positive electrode to the negative electrode through the solid electrolyte to reduce the conductive liquid metal. When the sodium ions in the conductive liquid metal reach saturation, the sodium ions in the conductive liquid metal continue to be reduced to solid metal sodium, which is deposited on the current collector or the battery case.

Example 3

This embodiment is used to illustrate the structure of the dual flow battery described in Embodiment 1 above.

Figure 2 is a schematic diagram of the structure of a dual flow battery. As shown in Figure 2, a dual-flow battery can include: solid metal sodium or lithium or potassium, conductive liquid metal, battery case, positive electrode material, solid electrolyte tube, positive electrode liquid storage tank, negative electrode liquid storage tank, and two pumps ;

The solid electrolyte is used as a diaphragm to separate the battery casing into a closed positive electrode space and a negative electrode space, wherein the positive electrode space is connected to the positive electrode liquid storage tank, and the positive electrode liquid stored in the positive electrode liquid storage tank is pumped The positive electrode material is pumped into the positive electrode space; the negative electrode space is connected to the negative electrode liquid storage tank, and the negative electrode liquid storage tank accommodates solid metal sodium or lithium or potassium and the conductive liquid metal, through A pump pumps the conductive liquid metal contained in the negative electrode liquid storage tank into the negative electrode space. The working principle of the dual-flow battery is similar to that of the cylindrical battery, so I won’t repeat it here.

Example 4

This embodiment is used to illustrate the structure of the single flow battery described in Embodiment 1 above.

Figure 3 is a schematic diagram of the structure of a single flow battery. As shown in Figure 3, a single flow battery can include: solid metal sodium or lithium or potassium, conductive liquid metal, battery casing, positive electrode material, solid electrolyte tube, positive electrode liquid storage tank and pump;

The solid electrolyte is used as a diaphragm to separate the battery casing into a closed positive electrode space and a negative electrode space, wherein the positive electrode space is connected to the positive electrode liquid storage tank, and the positive electrode liquid storage tank is accommodated by the pump. The positive electrode material is pumped into the positive electrode space, and the negative electrode space is used to accommodate the solid metal sodium or lithium or potassium and the conductive liquid metal. The working principle of a single flow battery is similar to that of a cylindrical battery, and will not be repeated here.

Example 5

This embodiment is used to illustrate the structure of the planar battery described in Embodiment 1 above.

FIG. 4 is a schematic diagram of the structure of a flat battery. As shown in Figure 4, the solid electrolyte is a diaphragm, which separates the battery casing into a closed positive electrode space and a negative electrode space, the positive electrode space is used to accommodate the positive electrode material, and the negative electrode space is used to accommodate The solid metal sodium or lithium or potassium and the conductive liquid metal material. The working principle of the flat battery is similar to that of the cylindrical battery, so I won't repeat it here.

In each of the above embodiments, the battery casing is preferably a stainless steel casing, and the positive electrode material may include one of a liquid positive electrode material or a slurry positive electrode material. The preparation method of the conductive liquid metal described in the embodiment 1 of the present invention will be described in the following example 6, and the preparation method of the positive electrode material described in the embodiment 1 of the present invention will be described in examples 7-10.

Example 6

This embodiment is used to illustrate the preparation method of the conductive liquid metal in the above-mentioned embodiment 1.

The methods include:

In a protective atmosphere of argon, adding the alkali metal and the aromatic compound into the ether solvent according to a certain molar ratio, and standing still to obtain the conductive liquid metal;

Wherein, the alkali metal is any one or more of sodium metal (Na), lithium metal (Li) or potassium metal (K);

The aromatic compound is any one or more of biphenyl (BP), biphenyl derivatives, naphthalene (NP), naphthalene derivatives, anthracene or anthracene derivatives;

Among them; the derivatives of biphenyl can specifically be: biphenyl, dichlorobiphenyl, tetrachlorobiphenyl, terphenyl, x-methylbiphenyl, x-ethylbiphenyl, etc.;

Specifically, the derivatives of naphthalene can be: phenanthrene, dichloronaphthalene, tetrachloronaphthalene, x-methylnaphthalene, 1,4-dimethylnaphthalene, x-ethylnaphthalene.

The ether solvents include ether, methyl ether, ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (DEGDME), tetraethylene glycol dimethyl ether (TEGDME), dipropyl ether, diisopropyl ether, ethyl butyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1, 3-dioxolane, dimethoxymethane, 1,2-dimethoxypropane, dioxolane, 1,4-dioxane, ethylene oxide, propylene oxide, 1,1 - any one or more of diethoxyethane. Among them, one of DME, DEGDME or TEGDME is preferred.

Alkali metals and aromatic compounds react after being mixed in ether solvents. The following is an example of mixing sodium, biphenyl and DME solvents.

The reaction process is shown in the following formula 3:

The conductive liquid metal provided by the embodiment of the present invention is used as a part of the negative electrode material of the secondary battery of the present invention, and has liquid fluidity, good electronic conductivity and ion conductivity, low potential, high safety and good wettability, The cost is low, and the material resources are abundant. Using this material as the negative electrode of the battery has the characteristics of high specific energy and long cycle life.

Example 7

This example is used to illustrate the preparation method of the positive electrode material in the above-mentioned Example 1.

The positive electrode material is a liquid positive electrode material, specifically:

Take p-benzoquinone, derivatives of p-benzoquinone, anthraquinone, derivatives of anthraquinone, acenaphthoquinone, derivatives of acenaphthoquinone, phenanthrenequinone or derivatives of phenanthrenequinone or tetramethylpiperidine nitrogen oxide As a solute, any one of ethylene glycol dimethyl ether, propylene carbonate or tetraethylene glycol dimethyl ether is used as a solvent and a certain amount of sodium trifluoromethanesulfonate is added as a liquid composed of a supporting electrolyte.

Its preparation method can be:

Use 0.1-3mol of p-benzoquinone, p-benzoquinone derivatives, anthraquinone, anthraquinone derivatives, acenaphthoquinone, acenaphthoquinone derivatives, phenanthrenequinone or phenanthrenequinone derivatives as the solute, dissolve in The liquid cathode material is obtained by adding a certain amount of sodium trifluoromethanesulfonate supporting electrolyte to 1 L of any solvent of ethylene glycol dimethyl ether, propylene carbonate or tetraethylene glycol dimethyl ether.

For example, in a specific example, taking anthraquinone-propylene carbonate-sodium trifluoromethanesulfonate liquid positive electrode material as an example, the specific preparation steps are:

Weigh 2.08g of anthraquinone dissolved in 10mL of propylene carbonate solvent, add 1.4g of sodium trifluoromethanesulfonate as a supporting electrolyte at the same time, stir until completely dissolved to obtain the required liquid cathode material.

Example 8

This example is used to illustrate the preparation method of the positive electrode material in the above-mentioned Example 1.

The positive electrode material is a liquid positive electrode material, specifically:

It is a liquid composed of tetramethoxy piperidine oxide TEMPO as solute, propylene carbonate as solvent and a certain amount of sodium trifluoromethanesulfonate as supporting electrolyte.

Its preparation method can be:

Dissolve 1-3 mol of tetramethoxypiperidine nitrogen oxide in 1L of propylene carbonate solvent, add a certain amount of sodium trifluoromethanesulfonate supporting electrolyte, and let it stand for 1 hour to obtain the liquid positive electrode material .

Example 9

This example is used to illustrate the preparation method of the positive electrode material in the above-mentioned Example 1.

The positive electrode material is a liquid positive electrode material, specifically:

Use any of benzophenone, acenaphthene, naphthacene, pentacene or pyrene as the solute, and any of ethylene glycol dimethyl ether, diglyme, or tetraethylene glycol dimethyl ether as the solvent , composed of liquid.

Its preparation method can be:

Use 0.1-5mol of any one of benzophenone, acenaphthene, tetracene, pentacene or pyrene as the solute, dissolved in 1L of ethylene glycol dimethyl ether, diglyme, or tetraethylene glycol A certain amount of alkali metal is added to any solvent of dimethyl ether, and the liquid positive electrode material is obtained by standing still.

For example, in a specific example, taking naphthacene-DME-metal sodium liquid cathode material as an example, the specific preparation steps are:

Weigh 2.20 g of naphthacene and dissolve in 10 mL of DME solvent, add 160 mg of sodium metal as an additive at the same time, and stir until completely dissolved to obtain the required liquid cathode material.

Example 10

This example is used to illustrate the preparation method of the positive electrode material in the above-mentioned Example 1.

The positive electrode material is a liquid positive electrode material, specifically:

A solution composed of Na ₂ S _x as the solute and any of dimethyl sulfoxide, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether or water as the solvent.

Its preparation method includes:

According to the molar ratio of Na ₂ S/S=1/(x-1), add Na ₂ S and S to any solvent of dimethyl sulfoxide, diglyme, tetraethylene glycol dimethyl ether or water , and add a certain amount of supporting electrolyte and stir until completely dissolved, that is, the liquid positive electrode material is obtained.

For example, in a specific example, taking Na ₂ S _x -DMSO liquid cathode material as an example, the specific preparation steps are:

According to the molar ratio of Na ₂ S/S=1/(x-1), weigh an appropriate amount of Na ₂ S and S and add it to the dimethyl sulfoxide (DMSO) solution, and add a certain amount of trifluoromethanesulfonic acid at the same time Sodium is used as a supporting electrolyte and stirred until completely dissolved to obtain the desired liquid cathode material. The liquid positive electrode material has good solubility, for example, the solubility of Na ₂ S ₈ and Na ₂ S ₄ prepared by this method is greater than 1 mol/L.

Example 11

This example is used to illustrate the preparation method of the positive electrode material in the above-mentioned Example 1.

The positive electrode material is a slurry positive electrode material, and its preparation method comprises:

Na _0.44 MnO ₂ , NaTi ₂ (PO ₄ ) ₃ , Na ₃ V ₂ (PO ₄ ) ₃ , Na _0.8 Li _0.1 Ni _0.25 Mn _0.65 O ₂ , NaMg _0.1 Ni _0.4 Mn _0.2 Ti _0.3 O ₂ , S, K ₃ Fe(CN) ₆ , Na ₄ Fe(CN) ₆ , FePO ₄ , etc., any one or more solid powders and carbon powders of positive electrode active materials are mixed uniformly according to a certain mass ratio, and a certain amount of supporting electrolyte is added and stirred , that is, the liquid cathode material is obtained.

Example 12

This example is used to illustrate the preparation method of the positive electrode material in the above-mentioned Example 1.

The positive electrode material is a slurry positive electrode material, and its preparation method comprises:

Mix any one of the liquid positive electrode materials provided in Example 7, Example 8 or Example 9, and carbon powder uniformly in a certain mass ratio, add a certain amount of supporting electrolyte and stir to obtain the positive electrode material.

Example 13

In this embodiment, taking a symmetrical battery composed of conductive liquid metal as an electrode as an example, the charging and discharging performance of the conductive liquid metal material provided by the present invention is described.

In this embodiment, the structure of the symmetrical battery is a cylindrical battery, 1 ml of 1 mol/L conductive liquid metal is placed in the solid electrolyte tube, and 1 ml of 1 mol/L conductive liquid metal is placed in the gap between the electrolyte tube and the battery case. Carry out constant current charging and discharging, as shown in Figure 5, the charging voltage platform is close to 0.2V, the discharging platform is close to -0.2V, and the polarization voltage between charging and discharging is 0.4V. The test of charge and discharge performance shows that the conductive liquid metal used in the present invention has high electrochemical reversibility and can carry out charge and discharge cycles.

Example 14

This embodiment takes a symmetrical battery composed of conductive liquid metal and metal sodium as an example to illustrate the dissolution and deposition process of metal sodium in the conductive liquid metal provided in the embodiment of the present invention.

In this embodiment, the structure of the symmetrical battery is a cylindrical battery. Metal sodium is placed in the solid electrolyte tube and the gap between the metal sodium and the solid electrolyte tube is filled with conductive liquid metal. The gap between the solid electrolyte tube and the battery casing also contains Put metal sodium and conductive liquid metal, and then perform constant current charge and discharge, with a limited capacity of 3 mA. As shown in Figure 6, metal sodium can be reversibly dissolved and deposited in this liquid, and its discharge platform is -0.1V, and its charging platform is 0.1V; the charging and discharging polarization voltage is 0.2V, which is lower than that of a conductive liquid metal symmetric battery. Polarization (0.4V, as shown in embodiment 13), the less reason of polarization is that the solid metal sodium placed in the conductive liquid metal can supplement the reduction of sodium in the conductive liquid metal and keep the higher conductivity of the liquid metal; Fig. The electrochemical impedance spectroscopy shown in 7 shows that the resistance of the battery does not increase with the cycle, which shows that no solid electrolyte interface (solid electrolyte interface, SEI) film is formed on the surface of metallic sodium and no side reactions occur; as shown in Figure 8 The Raman spectrum also shows that excessive sodium metal is soaked in conductive liquid metal and no side reactions will occur. It is based on this that in Embodiment 1 of the present invention, a secondary battery composed of solid metal sodium or lithium or potassium, conductive liquid metal, solid electrolyte, positive electrode material and battery case can be realized.

Example 15

This embodiment is used for comparison and description: the battery formed by the solid metal sodium, conductive liquid metal, solid electrolyte, positive electrode material and battery casing provided by the embodiment of the present invention is compared with the battery made of only conductive liquid metal, solid electrolyte, positive electrode material and battery casing The difference in the discharge capacity of the battery composed of the body.

In the embodiment of the present invention, the structure of the battery 1 is that metal sodium is placed in the electrolyte tube, and the gap between the metal sodium and the electrolyte tube is filled with conductive liquid metal, and the gap between the electrolyte tube and the battery casing of the cylindrical battery accommodates Excessive Na ₂ S ₈ liquid cathode material, the discharge capacity of the battery depends on the negative electrode. Carry out constant current charge and discharge. The structure of battery 2 is that only conductive liquid metal is contained in the electrolyte tube, and excess Na ₂ S ₈ liquid positive electrode material is contained in the gap between the electrolyte tube and the battery casing of the cylindrical battery, and the discharge capacity of the battery depends on the negative electrode. Carry out constant current charge and discharge. Figure 9 is a performance comparison chart of the two batteries. It can be seen that the electricity released by battery 1 is 8mAh, which is much higher than the electricity released by battery 2 by 4mAh.

Example 16

This example is used to illustrate the charging and discharging performance of a battery composed of solid metal sodium, conductive liquid metal, solid electrolyte, and tetramethoxypiperidine oxide (TEMPO) liquid positive electrode material.

The structure of the battery is that metal sodium is placed in the electrolyte tube, and the gap between the metal sodium and the electrolyte tube is filled with conductive liquid metal. Methoxy piperidine oxide (TEMPO) liquid cathode material. Charge and discharge the battery with constant current, the voltage range is 2.5 to 3.6V. Figure 10 shows its charge and discharge curve. It can be seen that the discharge platform of the battery is 3.2V, the charging platform is 3.4V, and the platform capacity is about 170mAh/g.

Example 17

This example is used to illustrate the charging and discharging performance of a battery composed of solid metallic sodium, conductive liquid metal, solid electrolyte, and Na ₂ S ₈ liquid positive electrode material at 70°C.

The structure of the battery is that metal sodium is placed in the electrolyte tube, and the gap between the metal sodium and the electrolyte tube is filled with conductive liquid metal composed of metal sodium, biphenyl and tetraethylene glycol dimethyl ether (TEGDME). The electrolyte tube and the cylinder 1 milliliter of 1 mol/L Na ₂ S ₈ /DMSO liquid cathode material is contained in the gap between the battery casings of the battery. Place the battery in an oven at 70°C for constant current charge and discharge, with a voltage range of 1.8 to 2.5V and a current of 5mA. Figure 11 is the charge and discharge curve for the second week. It can be seen that the discharge capacity of the battery is 350mAh/g, and the capacity of 350mAh/g when charged to 2.5V has a high Coulombic efficiency. In addition, the battery of the present invention is not limited to work at 70°C, but includes a working range from room temperature to 150°C.

The secondary battery provided by the embodiment of the present invention puts solid metal sodium, lithium or potassium in the conductive liquid metal negative electrode, which greatly improves the energy density of the conductive liquid metal battery, and has high safety and low cost. The material resource that can be applied to the preparation of the secondary battery of the present invention is abundant, the specific energy of the battery is high, and the cycle life is long, and it can be used for large-scale energy storage in solar power generation, wind power generation, smart grid peak regulation, distributed power station, backup power supply or communication base station equipment.

The temperature, concentration, time and other parameters described in the above-mentioned embodiments are only specific examples, and are not limitations of the present invention. Those skilled in the art can adjust the above-mentioned parameters without paying creative work to obtain It has the same effect as the present invention, so the adjustment of each parameter value should be included in the protection scope of the present invention.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (9)

1. a kind of secondary cell, which is characterized in that the secondary cell includes solid metallic sodium or lithium or potassium, conductive liquid gold Category, solid electrolyte, positive electrode and battery case；

The solid metallic sodium or lithium or potassium and the conductive liquid metal are placed in the solid that the solid electrolyte is formed In electrolytic tube, alternatively, the solid metallic sodium or lithium or potassium and the conductive liquid metal are filled in the battery case Between the solid electrolyte, the solid metallic sodium or lithium or potassium form the secondary electricity together with conductive liquid metal The cathode in pond；

The conductive liquid metal includes any one or several in metallic sodium, lithium, potassium and aromatic compound and ether solvent Mix the liquid of generation；

The aromatic compound is arbitrary in the derivative of biphenyl, connection benzene derivate, naphthalene, naphthalene derivatives, anthracene or anthracene It is one or more；

The ether solvent includes ether, methyl ether, glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethyleneglycol dimethyl ether, dipropyl Ether, diisopropyl ether, ethyl-butyl ether, butyl oxide, diamyl ether, isoamyl ether, two hexyl ethers, tetrahydrofuran, 2- methyltetrahydrofurans, 1,3- dioxolanes, 4- methyl-1s, 3- dioxolanes, dimethoxymethane, 1,2- dimethoxy propanes, dioxolane, Any one or more in Isosorbide-5-Nitrae-dioxane, ethylene oxide, propylene oxide, 1,1- diethoxyethane；

The positive electrode is filled between the battery case and the solid electrolyte, is forming the secondary cell just Pole；

Wherein, the positive electrode includes more sulphion solution, anthraquinone solution, benzoquinones solution, iodine solution, Benzophenone solution or four Any or Na in methoxy piperide oxide TEMPO solution_0.44MnO₂、NaTi₂(PO₄)₃、Na₃V₂(PO₄)₃、 Na_0.8Li_0.1Ni_0.25Mn_0.65O₂、NaMg_0.1Ni_0.4Mn_0.2Ti_0.3O₂Or in S any one or more slurries formed with carbon dust or The more sulphion solution of person, anthraquinone solution, benzoquinones solution, iodine solution, Benzophenone solution or tetramethoxy piperidine oxide TEMPO are molten Any slurry formed with carbon dust in liquid.

2. secondary cell according to claim 1, which is characterized in that the secondary cell is cylindrical battery；

The solid electrolyte is tubulose, is placed in the battery case；

The solid metallic sodium or lithium or potassium are placed in the solid electrolyte tube, and conductive liquid metal is filled in metallic sodium Or between lithium or potassium and solid electrolyte.

3. secondary cell according to claim 1, which is characterized in that the secondary cell be double flow battery, the electricity Pond further includes：Anode fluid reservoir, cathode fluid reservoir and two pumps；

The solid electrolyte is membrane, and the battery case is divided into closed anode space and cathode space, wherein institute It states anode space with the anode fluid reservoir to be connected, is pumped into the positive electrode housed in anode fluid reservoir by a pump In the anode space；The cathode space is connected with the cathode fluid reservoir, and solid gold is housed in the cathode fluid reservoir Belong to sodium or lithium or potassium and the conductive liquid metal, the conductive liquid gold that will be housed by another pump in cathode fluid reservoir Category is pumped into the cathode space.

4. secondary cell according to claim 1, which is characterized in that the secondary cell be single flow battery, the electricity Pond further includes：Anode fluid reservoir and pump；

The solid electrolyte is membrane, and the battery case is divided into closed anode space and cathode space, wherein institute It states anode space with the anode fluid reservoir to be connected, is pumped into the positive electrode housed in anode fluid reservoir by the pump In the anode space, the cathode space is golden for housing the solid metallic sodium or lithium or potassium and the conductive liquid Belong to.

5. secondary cell according to claim 1, which is characterized in that the secondary cell is flat plate cell；

The solid electrolyte is membrane, and the battery case is divided into closed anode space and cathode space, it is described just Pole space is for housing the positive electrode, and the cathode space is for housing the solid metallic sodium or lithium or potassium and described Conductive liquid metal material.

6. secondary cell according to claim 1, which is characterized in that the preparation method of the conductive liquid metal includes：

In the protective atmosphere of argon gas, alkali metal and aromatic compound are added according to certain mol proportion in ether solvent, it is quiet It puts, obtains the conductive liquid metal negative material；

Wherein, the alkali metal is any one or more in metallic sodium, lithium metal or metallic potassium；

The aromatic compound is arbitrary in the derivative of biphenyl, connection benzene derivate, naphthalene, naphthalene derivatives, anthracene or anthracene It is one or more；

The ether solvent includes ether, methyl ether, glycol dimethyl ether, diethylene glycol dimethyl ether, tetraethyleneglycol dimethyl ether, dipropyl Ether, diisopropyl ether, ethyl-butyl ether, butyl oxide, diamyl ether, isoamyl ether, two hexyl ethers, tetrahydrofuran, 2- methyltetrahydrofurans, 1,3- dioxolanes, 4- methyl-1s, 3- dioxolanes, dimethoxymethane, 1,2- dimethoxy propanes, dioxolane, Any one or more in Isosorbide-5-Nitrae-dioxane, ethylene oxide, propylene oxide, 1,1- diethoxyethane.

7. secondary cell according to claim 1, which is characterized in that the solid electrolyte include for conduct sodium from The Na of son, lithium ion or potassium ion₃Zr₂Si₂PO₁₂Ceramics, Na- β "-Al₂O₃Ceramics, K- β "-Al₂O₃Ceramics, Li₇La₃Zr₂O₁₂Pottery Porcelain or Li₁₀GeP₂S₁₂Any one in ceramics.

It is 8. a kind of such as the purposes of claim 1-7 any one of them secondary cells, which is characterized in that the secondary cell is used for Solar power generation, wind-power electricity generation, intelligent grid peak regulation, the extensive energy storage device for being distributed power station, backup power supply or communication base station.

9. a kind of preparation method of the cathode of secondary cell as described in claim 1, which is characterized in that the described method includes：

In the protective atmosphere of argon gas, by conductive liquid metal be injected into solid electrolyte composition solid electrolyte tube in or Person is injected between battery case and the solid electrolyte；

Excessive solid metallic sodium or lithium or potassium are inserted in conductive liquid metal；

Negative wire is drawn from solid metallic；

After solid electrolyte nozzle is sealed static two hours to get to the cathode.