KR20240014265A - Organic secondary battery comprising an electrolyte containing an ehter-based solvent - Google Patents

Abstract

The present invention relates to an organic secondary battery containing an electrolyte containing an ether-based solvent. Specifically, the present invention provides an organic secondary battery including an electrode containing a radical organic active material and an electrolyte containing an ether-based solvent. This invention was prepared with support from the Korea Electric Power Corporation's corporate autonomous win-win program project.

Description

Organic secondary battery containing an electrolyte containing an etheric solvent {ORGANIC SECONDARY BATTERY COMPRISING AN ELECTROLYTE CONTAINING AN EHTER-BASED SOLVENT}

The present invention relates to an organic secondary battery containing an electrolyte containing an ether-based solvent. Specifically, the present invention relates to an organic secondary battery including an electrode containing a radical organic active material and an electrolyte containing an ether-based solvent.

The present invention is a technology for replacing currently commercialized lithium secondary batteries using inorganic materials. Currently commercialized lithium secondary batteries use inorganic lithium compounds as electrode materials. As the lithium secondary battery market expands, the price of lithium raw materials is rising rapidly, and lithium secondary batteries are difficult to dispose of or recycle, causing environmental pollution.

The present invention relates to an organic secondary battery using an electrode for an organic secondary battery containing an organic material, specifically a radical organic active material, and an electrolyte containing an ether-based solvent.

Organic secondary batteries using electrodes containing radical organic active materials do not use lithium raw materials, so they are environmentally friendly, easy to recycle or dispose of, and are light in weight. The organic secondary battery using the electrode of the present invention has the advantage of being capable of high output and fast charging (within 10 minutes) and significantly reducing production costs.

In this regard, secondary batteries containing conventional organic active materials use carbonate-based electrolytes, but when carbonate-based electrolytes are used, there is a problem in that self-discharge occurs because the organic active materials are dissolved in the electrolyte. Therefore, although it has the advantage of enabling high output and high-speed charging and significantly reducing production costs, there are problems with long-term use such as reduced lifespan performance due to loss of organic active materials.

Domestic Patent Publication No. 10-2018-0023286

Tae Sin Kim et al., Carbon conductor- and binder-free organic electrode for flexible organic rechargeable batteries with high energy density, Journal of Power Sources 361 (2017), p15-20

The purpose of the present invention is to provide an organic secondary battery with improved electrochemical performance because the radical organic active material is not dissolved in the electrolyte.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above purpose,

This invention

Electrodes containing radical organic active materials and

In an organic secondary battery containing an electrolyte containing an ether-based solvent, the radical organic active material is conjugated hydrocarbon, conjugated amine, conjugated thioether, organodisulfide, It is a compound selected from the group consisting of organic substances and derivatives thereof with a thioether, nitroxyl radical, conjugated carbonyl, and sulfonyloxy radical structures,

An organic secondary battery is provided, wherein the voltage corresponding to 50% of the nominal capacity in the voltage-capacity curve of the organic secondary battery is formed at 3.7V (vs. Li/Li ⁺ ) or more.

In one embodiment of the present invention, the ether-based solvent is dimethyl ether, dibutyl ether, 1,3-dioxolane, polyethylene glycol dimethyl ether ( poly(ethylene glycol) Dimethyl Ether), tetraethylene glycol dimethyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran ( It may include one or more types from the group consisting of 2-methyltetrahydrofuran) and tetrahydrofuran.

In one embodiment of the present invention,

The radical organic active material is,

It may be one or more compounds selected from the following formulas 1 to 3.

[Formula 1]

Here, R is polystyrene, polyacrylate, polymethacrylate, polyacrylamide, polyvinyl ether, polyether, polynorbornene, polyethylene glycol, silica, or a copolymer thereof.

[Formula 2]

In Formula 2, n is an integer from 5 to 100.

[Formula 3]

In Formula 3, n is an integer from 5 to 100.

In one embodiment of the present invention, the radical organic active material changes an aminooxy anion into a nitroxide radical moiety, and the nitroxide radical moiety changes into an oxoammonium cation. (oxoammonium cation), the oxoammonium cation is converted into a nitroxide radical, and the nitroxide radical moiety is converted into an aminooxy anion. It may be discharged through a mechanism that changes to .

In one embodiment of the present invention, the salt included in the electrolyte is LiClO4, LiPF4, LiPF6, LiAsF6, LiTFSI, LiCF3SO3, Li[(C2F5)3PF3](LiFAP), Li[B(C2O4)2](LiBOB) , Li[N(SO2F)2](LiFSI), LiBeti(LiN[SO2C2F5]2), NaClO4, NaPF4, NaPF6, NaAsF6, NaTFSI, NaCF3SO3, Na[(C2F5)3PF3](NaFAP), Na[B(C2O4) )2](NaBOB), Na[N(SO2F)2](NaFSI), and NaBeti(NaN[SO2C2F5]2).

In one embodiment of the present invention, the opposite electrode of the electrode containing the radical organic active material is a negative electrode, and the negative electrode is from the group consisting of lithium metal, sodium metal, graphite, hard carbon, soft carbon, and n-type organic negative electrode. It may contain one or more selected compounds.

In one embodiment of the present invention, the voltage-capacity curve may be a voltage-capacity curve derived within 1 to 10 cycles of an organic secondary battery.

In one embodiment of the present invention, the voltage-capacity curve may be a voltage-capacity curve derived from an applied current range of 0.1 to 3.0 C-rate.

The means for solving the above problems do not enumerate all the features of the present invention. The various features of the present invention and its advantages and effects can be understood in more detail by referring to the specific examples below.

According to the present invention, by providing a radical organic active material and an ether-based solvent used for the radical organic active material, it is possible to increase the charge and discharge voltage of the secondary battery and at the same time improve the energy density of the battery.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

Figure 1 shows the electrochemical reaction mechanism of a PTVE material containing TEMPO according to an embodiment of the present invention.
Figure 2 shows the degree of dissolution of the radical organic active material in an electrolyte containing a carbonate-based solvent.
Figure 3 shows the degree of dissolution of radical organic active materials in an electrolyte containing an ether-based solvent.
Figure 4 shows the voltage-capacity curves of the batteries manufactured in Examples and Comparative Examples and the corresponding voltage at 50% of the nominal capacity of the battery.

Hereinafter, the principles of preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings and description. However, the drawings shown below and the description below are for preferred implementation methods among various methods for effectively explaining the characteristics of the present invention, and the present invention is not limited to the drawings and description below.

Meanwhile, terms such as first or second may be used to describe various components, but these terms should be interpreted only for the purpose of distinguishing one component from other components. For example, a first component may be named a second component, and similarly, the second component may also be named a first component.

Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to designate the presence of the described features, numbers, steps, operations, components, parts, or combinations thereof, and are intended to indicate the presence of one or more other features or numbers, It should be understood that this does not exclude in advance the possibility of the presence or addition of steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art. Terms as defined in commonly used dictionaries should be interpreted as having meanings consistent with the meanings they have in the context of the related technology, and unless clearly defined in this specification, should not be interpreted in an idealized or overly formal sense. No.

Hereinafter, the present invention will be described in more detail through the attached drawings and specific examples.

According to the present invention, the present invention

Electrodes containing radical organic active materials and

In an organic secondary battery containing an electrolyte containing an ether-based solvent, the radical organic active material is conjugated hydrocarbon, conjugated amine, conjugated thioether, organodisulfide, It is a compound selected from the group consisting of organic substances and derivatives thereof with a thioether, nitroxyl radical, conjugated carbonyl, and sulfonyloxy radical structures,

An organic secondary battery is provided, wherein the voltage corresponding to 50% of the nominal capacity in the voltage-capacity curve of the organic secondary battery is formed at 3.7V (vs. Li/Li ⁺ ) or more.

In one embodiment of the present invention, the ether-based solvent is dimethyl ether, dibutyl ether, 1,3-dioxolane, polyethylene glycol dimethyl ether (poly (ethylene glycol) Dimethyl Ether), tetraethylene glycol dimethyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran (2 It may contain one or more compounds selected from the group consisting of -methyltetrahydrofuran) and tetrahydrofuran.

Organic secondary batteries containing radical organic active materials generally use an electrolyte containing a carbonate-based solvent. A representative example is an electrolyte containing LiPF ₆ and ethylene carbonate (EC)/dimethyl carbonate (DMC)/diethyl carbonate (DEC) in a specific ratio.

However, the radical organic active material has the property of dissolving in the carbonate-based electrolyte. Therefore, when the radical organic active material and the carbonate-based electrolyte are used together, structural deformation of the electrode is likely to occur, and the dissolved radical organic active material passes through the separation membrane. There was a problem that the overall performance of the battery could be deteriorated by migration and deposition to the opposite electrode.

In order to solve the above-mentioned problems of organic secondary batteries, the inventors of the present invention discovered that radical organic active materials, specifically compounds containing a TEMPO functional group, do not dissolve in an electrolyte containing an ether-based solvent, and came up with the present invention.

According to the present invention, the electrolyte containing the ether-based solvent has the effect of minimizing the structural deformation of the electrode during the charging/discharging process of the organic secondary battery because the radical organic active material of the organic secondary battery hardly occurs. Furthermore, the inventors of the present invention discovered that when an ether-based solvent is applied to an organic secondary battery containing a radical organic active material, the charge/discharge voltage range can be expanded, thereby increasing the energy density of the battery, and thus came to the present invention.

As described above, in the organic secondary battery of the present invention, the radical organic active material is conjugated hydrocarbon, conjugated amine, conjugated thioether, organodisulfide, and thioether. , Nitroxyl radical, conjugated carbonyl, sulfonyloxy radical (Sulfonyloxy radical) structure organic substances and derivatives thereof may be included.

Specifically, the radical organic active material may be one or more compounds selected from the following formulas 1 to 3.

[Formula 1]

Here, R is polystyrene, polyacrylate, polymethacrylate, polyacrylamide, polyvinyl ether, polyether, polynorbornene, polyethylene glycol, silica, or a copolymer thereof.

[Formula 2]

n is an integer from 5 to 100.

[Formula 3]

n is an integer from 5 to 100.

Meanwhile, the radical organic active material itself can be used as an electrode active material, but it can also be mixed with other general positive electrode active materials to form an electrode. Specifically, when forming an electrode by mixing with other positive electrode active materials, the radical organic active material may be included in an amount of 50% by weight or less based on the total weight of the electrode including the radical organic active material. At this time, the positive electrode active material is a compound capable of reversible Lithiation and De-Lithiation, and may specifically include, but is limited to, a lithium complex metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel, or aluminum. It doesn't work.

The radical organic active material undergoes a two-step reaction in which an aminooxy anion changes into a nitroxide radical moiety, and the nitroxide radical moiety changes into an oxoammonium cation. The battery can be charged through the mechanism.

On the other hand, during discharge, the oxoammonium cation changes into a nitroxide radical, and the nitroxide radical moiety changes into an aminooxy anion, using a two-step reaction mechanism. The battery may be discharged through

Here, Formula 2 is a structure in which one 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) is placed in the monomer and one electron participates in an electrochemical reaction. The formula (3) is Di-TEMPO, which is a structure in which two TEMPOs are arranged in one monomer and two electrons participate in an electrochemical reaction.

Figure 1 shows the electrochemical mechanism of the PTVE organic electrode material containing TEMPO. The upper electrochemical reaction equation of Figure 1 represents a reaction involving one electron, and the lower electrochemical reaction equation of Figure 1 represents a reaction involving two electrons. indicates a reaction.

In one embodiment of the present invention, the organic secondary battery of the present invention has a voltage corresponding to 50% of the nominal capacity in the voltage-capacity curve of the organic secondary battery of 3.7V (vs. Li/Li ⁺ ) It may be formed from the above.

에서 0.2C의 방전 전류로 방전을 진행했을 때의 용량을 의미한다.In the present invention, the nominal capacity is at room temperature (25

This refers to the capacity when discharging with a discharge current of 0.2C.

Specifically, the voltage-capacity curve of the organic secondary battery may be any voltage-capacity curve derived within 1 to 50 cycles of the organic secondary battery.

In the voltage-capacity curve of an organic secondary battery, the voltage corresponding to 50% of the nominal capacity is formed above 3.7V (vs. Li/Li ⁺ ), which is the electrochemical reaction potential window. This means that the has widened, meaning that the energy density of the battery can be increased. When the organic secondary battery of the present invention uses a radical organic active material and an ether-based solvent, the electrochemical reaction voltage window can be higher than when a conventional carbonate-based solvent is used, and thus the energy density can be increased (Figure 4).

According to another embodiment of the present invention, an electrode containing the radical organic active material of the present invention includes a metal thin film layer; And it can be manufactured by applying a slurry containing a radical organic active material, a conductive material, and a binder to at least one surface of the metal thin film layer.

In one embodiment of the present invention, the metal forming the metal thin film layer may be one or two or more alloys selected from the group consisting of copper, aluminum, nickel, titanium, and stainless steel. As a specific example, the metal The thin film layer may be aluminum foil (Al foil).

In one embodiment of the present invention, the slurry may be formed on one or both sides of the metal thin film layer. As a specific example, the coating layer may be formed on one side of the metal thin film layer.

In one embodiment of the present invention, the conductive material may be one or more selected from the group consisting of carbon black, acetylene black, Ketjen black, channel black, Parness black, lamp black, thermal black, carbon nanotubes, and carbon fiber. .

In one embodiment of the present invention, the binder is PVdF-based, SBR-based, CMC-based, PI (polyimide)-based polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride. , polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene- It may be selected from the group consisting of butadiene rubber, epoxy resin, nylon, and combinations thereof.

In one embodiment of the present invention, the slurry is composed of 60% to 80% by weight of radical organic active material, 10% to 30% by weight of conductive material, and 3% to 10% by weight of binder based on the total weight of the slurry. It could be.

In one embodiment of the present invention, in a secondary battery containing the radical organic active material and an ether-based electrolyte, the salt used in the ether-based electrolyte is LiClO ₄ , LiPF ₄ , LiPF ₆ , LiAsF ₆ , LiTFSI, LiCF ₃ SO ₃ , Li[(C ₂ F ₅ ) ₃ PF ₃ ](LiFAP), Li[B(C ₂ O ₄ ) ₂ ](LiBOB), Li[N(SO ₂ F) ₂ ](LiFSI), LiBeti(LiN[ SO ₂ C ₂ F ₅ ] ₂ ), NaClO ₄ , NaPF 4 , NaPF ₆ , NaAsF ₆ , NaTFSI, NaCF _{3 SO 3} , Na[(C ₂ F ₅ ) ₃ PF ₃ ](NaFAP), Na[B(C ₂ O ₄ ) ₂ ](NaBOB), Na[N(SO ₂ F) ₂ ](NaFSI), NaBeti(NaN[SO ₂ C ₂ F ₅ ] ₂ ), or a combination thereof.

In a secondary battery containing the radical organic active material and an ether-based electrolyte, lithium metal, sodium metal, graphite, hard carbon, soft carbon, n-type organic negative electrode, etc. may be used as the negative electrode.

Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention may be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. Examples of the present invention are provided to more completely explain the present invention to those with average knowledge in the art.

Example 1: LiPF ₆ -Secondary battery containing TEGDME electrolyte

7g of PTVE as a radical organic active material, 2.5g of acetylene black as a conductive material, and 0.5g of PVdF as a binder were mixed and stirred for 30 minutes to prepare a slurry. Afterwards, an electrode was manufactured by applying it on Al foil. After drying, the manufactured electrode was punched into a 1 cm ² spherical electrode and used as an electrode for a coin cell.

An organic secondary battery was manufactured using an electrode containing a radical organic active material, Li foil (counter electrode), and an electrolyte in which 1M LiPF ₆ salt was dissolved in tetraethylene glycol dimethyl ether (TEGDME), an ether-based solvent. did.

Example 2: Secondary battery containing LiTFSi-TEGDME electrolyte

An organic secondary battery was manufactured in the same manner as Example 1, except that 1M LiTFSI salt was used instead of 1M LiPF ₆ salt.

Example 3: Secondary battery containing LiTFSi-PEGDME electrolyte

An organic secondary battery was manufactured in the same manner as in Example 1, except that 1M LiTFSI salt was used instead of 1M LiPF ₆ salt, and poly(ethylene glycol) Dimethyl Ether (PEGDME) was used instead of TEGDME. .

Comparative Example 1: Secondary battery containing LIPF6-EC/DEC electrolyte

Organic secondary solvent was prepared in the same manner as in Example 1, except that the carbonate-based solvent ethylene carbonate (EC)/dimethylene carbonate (DMC) (volume ratio = 1:1) was used instead of the ether-based solvent TEGDME. A battery was produced.

Experimental Example 1: Radical organic active material dissolution experiment

After adding the radical organic active material powder to the carbonate-based electrolyte prepared in Comparative Example 1, it was stirred at 50 rpm for 1 hour using a magnetic bar, and the state of the mixed solution was checked. The results are shown in Figure 2. In the electrolyte prepared in Comparative Example 1, it was confirmed that all of the radical organic active material powder was dissolved in the electrolyte containing the carbonate-based solvent.

After adding the radical organic active material powder to the electrolytes prepared in Examples 1 to 3, the mixture was stirred at 50 rpm for 1 hour using a magnetic bar, and the state of the mixed solution was checked. The results are shown in Figure 3. It can be confirmed that the radical organic active material powder is not dissolved in the ether-based electrolyte prepared in Examples 1 to 3.

Experimental Example 2: Electrochemical experiment

The electrochemical performance of the organic secondary batteries manufactured in Examples 1 to 3 and Comparative Example 1 was measured by applying a charging current of 0.2 C-rate and a discharging current of 0.2 C-rate in the range of 3.0V to 4.0V, and the results are shown. It is shown in 4.

In the organic secondary battery produced in Comparative Example 1, it can be confirmed that the voltage corresponding to the 50% nominal capacity point is 3.56V. On the other hand, in the voltage capacity curve of the organic secondary battery manufactured in Example 1, the voltage corresponding to the 50% nominal capacity point was 3.72V, 3.79V for the organic secondary battery manufactured in Example 2, and 3.79V for the organic secondary battery manufactured in Example 3. It was confirmed that the battery showed 3.79V as the corresponding voltage.

Claims (7)

Electrodes containing radical organic active materials and
In an organic secondary battery containing an electrolyte containing an ether-based solvent, the radical organic active material is conjugated hydrocarbon, conjugated amine, conjugated thioether, organodisulfide, It is a compound selected from the group consisting of organic substances and derivatives thereof with a thioether, nitroxyl radical, conjugated carbonyl, and sulfonyloxy radical structures,
An organic secondary battery, in which the voltage corresponding to 50% of the nominal capacity in the voltage-capacity curve of the organic secondary battery is formed at 3.7V (vs. Li/Li ⁺ ) or more.
According to paragraph 1,
The ether-based solvent is,
Dimethyl ether, dibutyl ether, 1,3-dioxolane, poly(ethylene glycol) Dimethyl Ether, tetraethylene glycol Dimethyl ether (Tetraethylene glycol dimethyl ether), tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, and tetrahydrofuran An organic secondary battery containing one or more types from the group.
According to paragraph 1,
The radical organic active material is,
An organic secondary battery, which is one or more compounds selected from the following formulas 1 to 3.
[Formula 1]

Here, R is polystyrene, polyacrylate, polymethacrylate, polyacrylamide, polyvinyl ether, polyether, polynorbornene, polyethylene glycol, silica, or a copolymer thereof.
[Formula 2]

In Formula 2, n is an integer from 5 to 100.
[Formula 3]

In Formula 3, n is an integer from 5 to 100.
According to paragraph 1,
The radical organic active material is
Charged through a mechanism in which an aminooxy anion is converted into a nitroxide radical moiety, and the nitroxide radical moiety is converted into an oxoammonium cation,
The oxoammonium cation is converted into a nitroxide radical, and the nitroxide radical moiety is discharged through a mechanism whereby the nitroxide radical moiety is converted into an aminooxy anion.
Organic secondary battery.
According to paragraph 1,
Salts included in the electrolyte include LiClO ₄ , LiPF ₄ , LiPF 6 , LiAsF ₆ , LiTFSI, LiCF ₃ SO ₃ , Li[(C ₂ F ₅ ) ₃ PF ₃ ] ₍ LiFAP), Li[B(C ₂ O ₄ ) ₂ ](LiBOB), Li[N(SO ₂ F) ₂ ](LiFSI), LiBeti(LiN[SO ₂ C ₂ F ₅ ] ₂ ), NaClO ₄ , NaPF ₄ , NaPF ₆ , NaAsF ₆ , NaTFSI, NaCF ₃ SO ₃ , Na[(C ₂ F ₅ ) ₃ PF ₃ ](NaFAP), Na[B(C ₂ O ₄ ) ₂ ](NaBOB), Na[N(SO ₂ F) ₂ ](NaFSI), and An organic secondary battery comprising at least one compound selected from the group consisting of NaBeti (NaN[SO ₂ C ₂ F ₅ ] ₂ ).
According to paragraph 1,
The opposite electrode of the electrode containing the radical organic active material is the cathode,
The negative electrode includes one or more compounds selected from the group consisting of lithium metal, sodium metal, graphite, hard carbon, soft carbon, and n-type organic negative electrode.
Organic secondary battery.
According to paragraph 1,
The electrode containing the radical organic active material further includes a positive electrode active material different from the radical organic active material,
The radical organic active material is contained in an amount of 50% by weight or less based on the total weight of the electrode containing the radical organic active material,
An organic secondary battery wherein the positive electrode active material is a lithium composite metal oxide containing lithium and one or more metals selected from cobalt, manganese, nickel, and aluminum.