KR20170061450A - Reference electrode with improved durability and secondary battery comprising the same - Google Patents

Abstract

In the present invention, a wire-shaped current collector; A reference electrode active material layer formed on one end of the wire-shaped current collector; And a polymer mesh layer surrounding the reference electrode active material layer. The reference electrode is excellent in durability and enables accurate measurement of the electrode behavior of the secondary battery.

Description

Technical Field [0001] The present invention relates to a reference electrode having improved durability and a secondary battery having the reference electrode,

The present invention relates to a reference electrode having improved durability and a secondary battery having the reference electrode.

In order to investigate the behavior of the cathode and the anode, experiments using three electrodes composed of an anode, a cathode, and a reference electrode have been conducted.

Conventionally, the reference electrode is disposed outside the anode and the cathode, and thus the reference electrode can not accurately read the current flow. In addition, the reference electrode is formed to have a thick thickness, and the current flow can not be accurately read.

To solve this problem, there has been an attempt to insert a reference electrode between the anode and the cathode. However, when the reference electrode is inserted between the anode and the cathode, the reference electrode tends to separate from the current collector due to the pressure applied from the outside of the electrode. As a result, the cell test result using the three electrodes becomes inaccurate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a reference electrode having improved durability.

Another object of the present invention is to provide a secondary battery including the reference electrode.

It is to be understood, however, that the technical scope of the present invention is not limited to the above-mentioned problems, and other technical subjects not mentioned above can be understood by those skilled in the art from the description of the invention described below.

According to an aspect of the present invention, there is provided a current collector comprising: a wire-shaped current collector; A reference electrode active material layer formed on a portion of the wire-shaped current collector; And a polymer mesh layer surrounding the reference electrode active material layer.

The wire-shaped current collector may be formed of copper or nickel-coated copper.

The wire-shaped current collector may have a cylindrical or elliptical cross section.

The wire-shaped current collector may have an average diameter in the range of 100 to 300 mu m.

The reference electrode active material layer is coated on one end of the wire-shaped current collector, and the other end of the wire-like current collector may be in the form of an uncoated portion.

The unprinted portion may be a lead portion of the reference electrode.

The reference electrode active material may be supported on the wire-shaped current collector in an amount of 0.3 to 0.7 mAh / cm ² .

The reference electrode active material layer may be formed to a thickness of 3 to 30 [mu] m on a wire-shaped current collector.

The active material of the reference electrode active material layer may be lithium titanium oxide represented by Li _x Ti _y O ₄ (0.5? X? 3, ₁ ? Y? 2.5).

The lithium-titanium oxide is _{Li 4/3 Ti 5/3} O 4, LiTi 2 O 4, Li 8/7 Ti 12/7 O 4 and _{Li 4/5 Ti 11/5} O 4 , selected from the group consisting of one or It may be a mixture of two or more.

The polymeric mesh layer may surround the reference electrode active material layer in a thickness ranging from 5 to 15 mu m.

Wherein the polymeric mesh layer comprises one or two species selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichlorethylene and polyvinylidene fluoride-chlorotrifluoroethylene Or mixtures thereof.

According to another aspect of the present invention, there is provided a secondary battery electrode assembly including a reference electrode, wherein the reference electrode is the reference electrode described above, and is laminated in the order of an anode, a separator, a reference electrode, a separator, A battery electrode assembly is provided.

According to another aspect of the present invention, there is provided a secondary battery comprising the above-described electrode assembly and an electrolytic solution, wherein the electrolytic solution moves through the pores of the polymer mesh layer of the reference electrode and reaches the reference electrode active material.

According to still another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: preparing a wire-shaped current collector to be used for a reference electrode (step S1); Preparing a slurry for forming a reference electrode active material layer, coating and drying the slurry on a wire-shaped current collector (step S2); And coating and drying (S3) a slurry for forming a polymer mesh layer on the reference electrode active material layer, wherein the drying is performed at a temperature of from room temperature to 60 DEG C for 1 hour to 5 minutes And a secondary drying is performed for 5 to 30 minutes at a temperature of 130 to 150 ° C.

As a solvent of the slurry for forming the polymer mesh layer, one or a mixture of two or more selected from the group consisting of water, acetone, and alcohol may be used.

According to an aspect of the present invention, there is provided a reference electrode in which durability is improved and the problem that the electrode active material is released from the wire-shaped current collector is eliminated.

More specifically, the polymer mesh layer formed on the reference electrode active material layer prevents separation of the reference electrode active material to improve the durability of the reference electrode, and the electrolyte easily reaches the reference electrode active material through the pores formed in the polymer mesh layer I can do it. In addition, since the polymer mesh layer can be swelled by the electrolyte solution, it can function as a buffer against external pressure and changes in the active material volume that occur during cell charging and discharging.

In addition, the reference electrode of the present invention can ensure proper isolation with a working electrode such as a cathode or an anode due to the polymer mesh layer and the wire-shaped current collector.

Thus, the reference electrode according to the present invention can exhibit high durability and can accurately measure the secondary battery.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further the understanding of the technical idea of the invention. And should not be construed as limiting.
1 is an exploded view of an electrode assembly according to an embodiment of the present invention.
2 is a schematic cross-sectional view of a reference electrode according to an embodiment of the present invention.
3 is a schematic illustration of a side view of a reference electrode in accordance with an aspect of the present invention.
4 is an SEM image of a reference electrode section according to an embodiment of the present invention.
5 is an SEM image of a polymer mesh layer constituting a reference electrode according to an embodiment of the present invention.
6 is a graph showing the results of EIS measurement for analyzing the interfacial resistance of the battery manufactured in Examples / Comparative Examples.
7 is a graph showing the results of EIS measurement for analyzing the interfacial resistance of the negative electrode manufactured in the example / comparative example.
8 is a graph showing the results of EIS measurement for analyzing the interfacial resistance of the anode fabricated in the example / comparative example.
9 shows the 0.4C charge / discharge profile of the battery manufactured in the example / comparative example.
10 shows the 0.4C charge / discharge profile of the anode fabricated in the example / comparative example.
Fig. 11 shows the 0.4C charge / discharge profile of the negative electrode manufactured in the example / comparative example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

First, an electrode assembly according to an embodiment of the present invention will be described with reference to FIG.

1 is an exploded view of an electrode assembly according to an embodiment of the present invention.

The electrode assembly includes an anode 110, a cathode 130, separators 121 and 122, and a reference electrode 200. Although FIG. 1 shows only an embodiment in which the electrode assembly is formed by being laminated, it is needless to say that the electrode assembly may be formed in a jelly-roll shape.

The reference electrode is provided for measuring the electrode behavior of the secondary battery, and may be positioned between the cathode and the anode. More specifically, the cathode, the separator, the reference electrode, the separator, and the anode are stacked in this order so that the reference electrode is not in direct contact with the anode or the cathode. If the separator is not interposed between the reference electrode and the anode or between the reference electrode and the cathode, the wire-shaped current collector constituting the reference electrode can react with the cathode or the anode, and the electrode behavior of the secondary battery can not be measured accurately There is a possibility. If the separator is not interposed between the reference electrode and the positive electrode or the reference electrode and the negative electrode, the active material layer of the reference electrode and the positive electrode or the negative electrode may be in direct contact with each other to generate an internal short circuit.

The direction in which the reference electrode is inserted into the electrode assembly is not particularly limited. For example, the working electrode lead may be inserted in the direction in which it is drawn out or in the opposite direction.

The anode may be formed, for example, by applying a cathode active material to a collector plate made of aluminum (Al). The negative electrode may be formed, for example, by applying a negative electrode active material to a collector plate made of copper (Cu).

As the positive electrode active material is, for _{example, LiCoO 2, LiNiO 2, LiNi} 1 - y Co y O 2 (0 <y <1), LiMO 2 (M = Mn, Fe , etc.), Li (Ni _a Co _b Mn layers, such as _{y Mn y O 2 (O≤y <} 1) - c) O 2 (0 <a <1, 0 <b <1, 0 <c <1, a + b + c = 1), LiNi 1 Hip type cathode active material; _{LiMn 2 O 4, LiMn 2 -} z Co z O 4 (0 <z <2), LiMn 2 - z Ni z O 4 (0 <z <2), Li (Ni a Co b Mn c) O 4 (0 a <b <2, 0 <b <2, 0 <c <2, a + b + c = 2); An olivine-type cathode active material such as LiCoPO ₄ , LiFePO _4, or the like can be used.

Examples of the negative electrode active material include carbonaceous materials such as petroleum coke, activated carbon, graphite, non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1 - x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' A metal complex oxide of Al, B, P, Si, Group 1, Group 2 or Group 3 elements of the periodic table, halogen, 0 < x1 &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, Bi ₂ O ₅ and the like; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

As the separator, a polyolefin-based film such as porous polyethylene or porous polypropylene, an organic / inorganic composite separator in which a porous coating layer is formed on a porous substrate, a nonwoven film, engineering plastic or the like can be used. It is not. As a process for applying the separator to a battery, a lamination, stacking and folding process of a separator and an electrode can be performed in addition to a general process of winding.

The electrode assembly is stored in the battery case and filled with the electrolyte, so that ions generated by the chemical reaction of the secondary battery can be moved. Such an electrolytic solution may include organic solvents and electrolytic salts commonly used in the art, and is not particularly limited in the present invention.

Referring to FIGS. 2 and 3, the reference electrode 200 includes a wire-shaped current collector 210; A portion of the wire-shaped current collector 210, more specifically, a reference electrode active material layer 220 formed at one end; And a polymer mesh layer (230) surrounding the reference electrode active material layer (220).

The wire-like current collector can be applied without limitation as long as it is a metal having good conductivity commonly used in the art. For example, copper coated with copper (Cu) or nickel (Ni) may be applied. When copper coated with nickel as a wire-shaped collector is applied, not only excellent conductivity due to copper but also excellent corrosion resistance due to nickel coated on the surface of copper can be provided.

The wire-shaped current collector preferably does not react with the working electrode for accurate measurement of the electrode cell behavior. To this end, it is desirable that the wire-shaped current collector has a three-dimensional shape such as a wire to reduce the specific surface area, thereby lowering the possibility of contact with the working electrode. The wire-shaped current collector is not particularly limited in its cross-sectional shape, and may be formed to have, for example, a cylindrical or elliptical cross section, but is not limited thereto.

The wire-shaped current collector may also have an average diameter in the range of about 100 to 300 mu m. If the diameter of the current collector is less than 100 탆, the wire may be broken during the manufacturing process. If the current collector is larger than 300 탆, the performance of the battery may be deteriorated due to interference. Therefore, when the reference electrode is formed with a thickness having an average diameter in the above range, the volume of the electrode current collector can be prevented from being unnecessarily increased due to the reference electrode, and deterioration of adhesion between the anode and the cathode can be prevented.

Also, the wire-shaped current collector may be manufactured to have different lengths depending on the type of the cell to be used. In one embodiment, the length may be 10 to 100 cm, but is not limited thereto.

The reference electrode active material layer 220 is coated on one end of the wire-shaped current collector in order to prevent the excessive volume increase due to the reference electrode and increase the distance between the anode and the cathode while coating the minimum active material for the reference potential measurement So that the potential of lithium ions discharged from the anode of the secondary battery and moving to the cathode through the electrolyte can be accurately measured. The current collector of the wire form has an uncoated portion in which the reference electrode active material layer is not formed at the other end, and extends to the outside of the electrode assembly to serve as a lead portion of the reference electrode.

The reference electrode active material layer may be formed on the wire-shaped current collector in a thickness of 3 to 30 mu m. If the thickness of the reference electrode active material layer is thinner than the lower limit value, the accurate potential measurement may not be performed. If the thickness is thicker than the upper limit value, the distance between the cathode and the anode may be unnecessarily increased.

Further, the reference electrode active material layer may be formed on the wire-shaped current collector with a length of 1 mm or 1 to 5 mm. If the length of the reference electrode active material layer is shorter than 1 mm, accurate potential measurement may not be performed. Also, even if it is formed longer than 5 mm, there is no significant influence on the potential measurement.

The amount of the reference electrode active material supported on the wire-shaped current collector is preferably 0.3 to 0.7 mAh / cm ² . If the loading amount of the reference electrode active material is less than the lower limit value, the accurate potential measurement may not be performed, and if it is more than the upper limit value, the battery performance may be affected.

As the reference electrode active material, lithium titanium oxide represented by Li _x Ti _y O ₄ (0.5? X? 3, ₁ ? Y? 2.5) can be used. Particular examples of the lithium-titanium oxide is _{Li 4/3 Ti 5/3 O 4, LiTi} 2 O 4, Li 8/7 Ti 12/7 O 4 and _{Li 4/5 Ti 11/5} O 4 group consisting of And mixtures thereof. However, the present invention is not limited thereto. The SEI layer is not formed at 2.0 V or less in the lithium titanium oxide. As a result, the SEI layer is formed on the surface of the lithium metal in the reference electrode manufactured using the lithium metal as the electrode active material, so that there is no problem that the electrolyte is further decomposed.

In addition to the reference electrode active material, the reference electrode active material layer may contain a binder polymer as required. Examples of the binder polymer include, but are not limited to, carboxymethylcellulose, vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, poly Methyl methacrylate, styrene butadiene rubber (SBR), and the like, but is not limited thereto. The binder polymer may be contained in an amount of 5 to 25 parts by weight based on 100 parts by weight of the active material of the reference electrode.

In addition, the reference electrode active material layer may include a conductive material to improve the conductivity of the reference electrode active material, if necessary. Non-limiting examples of conductive materials include low crystalline carbon such as soft carbon and hard carbon; Or natural graphite, Kish graphite, graphite, carbon nanotubes, pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon microbeads, liquid crystal pitch Mesophase pitches, and high-crystallization carbon such as petroleum and coal tar coke. However, the present invention is not limited thereto. The conductive material may be included in an amount of 3 to 15 parts by weight based on 100 parts by weight of the active material of the reference electrode.

The reference electrode active material layer is coated with a polymer mesh layer so that the active material of the reference electrode is prevented from being desorbed and the electrolyte can be easily passed through the polymer mesh layer to the reference electrode active material.

The polymer mesh layer may be formed by coating a reference electrode active material layer with a thickness in the range of 5 to 15 占 퐉, and the pores formed by solvent evaporation are formed in a mesh shape.

The polymer mesh layer may be formed of a polymer having the same or similar physical properties as the binder polymer used in the reference electrode active material layer and may be coated on the electrode active material layer while exhibiting excellent adhesion to the reference electrode active material layer. It can act as a kind of buffer when impregnating electrolyte. Wherein the polymeric mesh layer comprises one or two species selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichlorethylene and polyvinylidene fluoride-chlorotrifluoroethylene But it is not limited thereto.

An example of the method of manufacturing the reference electrode includes, but is not limited to, the following method.

First, a wire-shaped current collector to be used for the reference electrode is prepared (step S1).

For wire-type current collectors, refer to the above description.

Next, a slurry for forming a reference electrode active material layer is prepared and coated on a wire-shaped current collector (step S2).

To this end, the reference electrode active material is charged into a solvent and dispersed to prepare a slurry for forming a reference electrode active material layer. The above-mentioned contents are referred to for the components constituting the reference electrode active material layer. Examples of the solvent include tetrahydrofuran, methylene chloride, chloroform, dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) Cyclohexane, water, and mixtures thereof may be used, but are not limited thereto.

The slurry for forming the prepared reference electrode active material layer is coated on a wire-shaped current collector and dried. A dip coating process may be readily used to coat a wire-shaped current collector, but is not limited thereto.

Subsequently, a slurry for forming the polymer mesh layer is prepared, coated on the reference electrode active material layer, and dried (step S3).

The polymer to be used for forming the polymer mesh layer is dispersed in a solvent having high volatility to prepare a slurry for forming the polymer mesh layer.

For the polymer, see above.

Examples of the solvent that is highly volatile include a solvent that does not cause an electrochemical reaction in the electrolytic solution, for example, acetone, water, or alcohol, but is not limited thereto.

The slurry for forming the polymer mesh layer is coated on the reference electrode active material layer and dried. A dip coating process may be used for the coating, but the present invention is not limited thereto. After the coating, a drying process may be performed so that mesh-like pores may be formed in the polymer while the solvent evaporates. For this purpose, the drying process is a primary drying process for 5 to 30 minutes at a temperature of room temperature (25 ° C) to 60 ° C so as to form a porous polymeric mesh layer, , Preferably 130 to 150 캜, for 5 to 30 minutes to evaporate the solvent.

Upon completion of the drying process, a reference electrode according to an embodiment of the present invention is obtained.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

<Examples>

An anode, a cathode and a reference electrode were prepared as follows to prepare a pouch-shaped battery.

Preparation of positive electrode: A positive electrode containing Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ (NMC) as a positive electrode active material was prepared. The positive electrode mixture slurry was prepared by adding NMC, carbon black, and binder polyvinylidene fluoride (PVdF) at a ratio of 96 wt%, 2 wt%, and 2 wt% to N-methyl-2-pyrrolidone (NMP) , And dispersed. The positive electrode material mixture slurry was coated on an aluminum current collector having a thickness of 20 탆 to obtain a positive electrode having a capacity of 3.3 mAh / cm ² and a thickness of 130 탆.

Preparation of negative electrode: A negative electrode containing graphite as a negative active material was prepared. The anode mixture slurry was obtained by adding graphite, carbon black, and a styrene-butadiene rubber (SBR) binder as a binder to distilled water at a ratio of 96 wt%, 2 wt%, and 2 wt%, and mixing and dispersing. A negative electrode material mixture slurry was coated on the copper collector having a thickness of 20 ㎛ to give a negative electrode having a 3.7 mAh / cm ² and the specific capacity 150 ㎛ thickness.

Preparation of reference electrode: A reference electrode containing lithium-titanate-oxide (Li ₄ Ti ₅ O ₁₂ ) as a reference electrode active material was prepared. The reference electrode active material slurry was obtained by mixing and dispersing Li ₄ Ti ₅ O ₁₂ , carbon black and binder PVdF in acetone. A copper wire was prepared as a collector of the reference electrode. The slurry was applied to a copper wire end portion having a length of 1 to 5 mm of the total length of the copper wire by a dip coating method to form a reference electrode active material layer having a thickness of 10 탆. Then, polyvinylidene fluoride-hexafluoropropylene particles were dispersed in acetone and coated on the reference electrode active material layer by a dip coating method. Subsequently, primary drying is performed to form a porous polymer mesh layer at a temperature of from room temperature to 60 ° C, and then secondary drying is performed at a temperature of 130 ° C or higher to remove the residual solvent, thereby evaporating the acetone solvent. As a result, On the layer, large pores were formed relatively uniformly, and a polymer layer having a mesh shape was formed in the reference electrode active material layer.

Preparation of Cell: A polyethylene film was laminated on the anode prepared above, and then the reference electrode was laminated so that the active material coating portion of the reference electrode was placed on the separation membrane and the non-ionization portion was located outside the separation membrane. A polyethylene film was laminated on the reference electrode, and the negative electrode was laminated to obtain an electrode assembly. The electrode assembly was housed in a pouch for a secondary battery, and a liquid electrolyte including 1M LiCF _6- containing dimethyl carbonate (DEC) and ethylene carbonate (EC) 1: 1 was charged to prepare a pouch-type secondary battery.

<Comparative Example>

A reference electrode was prepared in the same manner as in Example except that a polymer mesh layer was not formed on the reference electrode active material layer, and a cell was prepared using the reference electrode.

Evaluation Example 1 :

EIS (electrochemical impedance spectroscope) was measured to analyze the charge transfer resistance. The measurements were carried out in duplicate, and the measured values for the examples were shown by red solid lines and dotted lines, and the values for the comparative examples were indicated by black solid lines and dotted lines in FIGS. 6 to 8. The EIS measuring instrument used was BioLogic VSP. In the case of the measurement, basically, the frequency range from 100 kHz to 50 mHz was measured at the amplitude of 30 mV in the potentiosat mode, and the frequency was measured three times for each frequency to increase the accuracy of the experiment. Resistance measurements were carried out at room temperature, measured at SOC50, and the results were converted to Nyquist plots. At this time, each interface resistance was analyzed by full cell and positive / negative electrode, and each interface resistance was represented by ASI which is the resistance multiplied by the electrode area.

As shown in FIG. 6, the interface resistance of the battery is similar regardless of the type of the reference electrode, but the resistance ratio between the cathode and the anode is different in the comparative example. This is because the reference electrode incorrectly distinguishes the resistance of the anode / cathode as the reference electrode is separated from the wire current collector due to the stress from the outside during the cell assembly process and the volume change of the electrode during charging and discharging of the cell. On the other hand, in the case of the embodiment, since the porous polymer layer serves as a buffer, it is possible to prevent the reference electrode from being detached, thereby improving the accuracy of the resistance value.

Evaluation Example 2 :

Since the charge transfer resistance is a method of measuring the resistance change in a short time, in order to measure the potential of the anode / cathode in the continuous reaction, the cell is charged and discharged at a room temperature of 0.4 C, / The potential of the negative electrode were respectively measured. The measurements were carried out in duplicate, and the measured values for the examples were shown by red solid lines and dotted lines, and the measured values for the comparative examples were indicated by black solid lines and dotted lines in FIGS.

As can be seen from FIG. 9, there is no difference between the charging and discharging profile of the battery in the comparative example and the embodiment, but it can be seen from FIGS. 10 and 11 that the charge / discharge profiles of the positive electrode / negative electrode are different. This is due to the inaccuracy of the interface resistance and the same reason.

Claims (16)

A wire-shaped collector;
A reference electrode active material layer formed on a portion of the wire-shaped current collector; And
A polymer mesh layer surrounding the reference electrode active material layer;
.
The method according to claim 1,
Wherein the wire-shaped current collector is formed of copper or nickel-coated copper.
The method according to claim 1,
Wherein the wire-shaped current collector has a cylindrical or elliptical cross section.
The method according to claim 1,
Wherein the wire-shaped current collector has an average diameter in the range of 100 to 300 mu m.
The method according to claim 1,
Wherein the reference electrode active material layer is coated on one end of the wire-shaped current collector, and the other end of the wire-shaped current collector is in the form of an uncoated portion.
6. The method of claim 5,
And the unoccupied portion is a lead portion of the reference electrode.
The method according to claim 1,
Wherein the reference electrode active material is supported on the wire-shaped current collector in an amount of 0.3 to 0.7 mAh / cm &lt; ² &gt;.
The method according to claim 1,
Wherein the reference electrode active material layer is formed in a wire-like current collector to a thickness of 3 to 30 占 퐉.
The method according to claim 1,
When the active material of the reference electrode active material layer is Li _x Ti _y O ₄ (0.5? X? 3, 1? Y? 2.5).
10. The method of claim 9,
The lithium-titanium oxide is _{Li 4/3 Ti 5/3} O 4, LiTi 2 O 4, Li 8/7 Ti 12/7 O 4 and _{Li 4/5 Ti 11/5} O 4 , selected from the group consisting of one or Wherein the reference electrode is a mixture of two or more species.
The method according to claim 1,
Wherein the polymeric mesh layer surrounds the reference electrode active material layer with a thickness in the range of 5 to 15 占 퐉.
The method according to claim 1,
Wherein the polymeric mesh layer comprises one or two species selected from polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichlorethylene and polyvinylidene fluoride-chlorotrifluoroethylene Wherein the reference electrode is formed from the mixture.
A secondary battery electrode assembly comprising a reference electrode,
Wherein the reference electrode is the reference electrode according to claim 1,
Wherein the positive electrode, the separator, the reference electrode, the separator, and the negative electrode are stacked in this order.
14. The secondary battery according to claim 13, comprising an electrode assembly and an electrolytic solution, wherein the electrolytic solution moves through the pores of the polymer mesh layer of the reference electrode and reaches the reference electrode active material.
Preparing a wire-like current collector to be used for the reference electrode (step S1);
Preparing a slurry for forming a reference electrode active material layer, coating and drying the slurry on a wire-shaped current collector (step S2); And
Preparing a slurry for forming the polymer mesh layer, and coating and drying the slurry on the reference electrode active material layer (step S3). At this time,
The drying is carried out at a temperature of from room temperature to 60 ° C for 5 to 30 minutes and then at a temperature of 130 to 150 ° C for 5 to 30 minutes.
A method of manufacturing a reference electrode.
16. The method of claim 15,
Wherein the solvent of the slurry for forming the polymer mesh layer is one or a mixture of two or more selected from the group consisting of water, acetone, and alcohol.

Images