CN114639830A - Visual lithium ion electrode, application and visual lithium ion battery - Google Patents

Abstract

The invention belongs to the technical field of lithium ion batteries, and discloses a visual lithium ion electrode, application and a visual lithium ion battery. The electrode comprises a transparent current collector film and a negative electrode active material or a positive electrode active material coated on the surface of the transparent current collector film. The visual lithium ion electrode is applied to the lithium ion battery to obtain two visual lithium ion batteries. The visual lithium ion battery can be used for in-situ observation of structural change, color change, gas production condition and lithium separation condition of a positive electrode material or a negative electrode material in an electrochemical reaction process in the charging and discharging processes of the battery.

Description

A visualization of lithium-ion electrodes and applications and visualization of lithium-ion batteries

technical field

The invention belongs to the technical field of lithium ion batteries, and in particular, relates to a visualized lithium ion electrode and application and a visualized lithium ion battery.

Background technique

Lithium-ion batteries are a new generation of rechargeable batteries following traditional batteries such as nickel-metal hydride batteries. Their high-capacity and long-life characteristics are widely used in energy storage, electric vehicles, and portable electronic products. With the development of lithium ion, especially the development of electric vehicles, higher requirements are placed on the specific energy, life, safety and price of lithium ion batteries. This motivates us to further investigate the complex electrochemical transport mechanism in batteries. The electrochemical mechanism is closely related to the structural evolution of electrode materials during charging and discharging. However, it is difficult to monitor the correlation between the electrochemical mechanism and the material of the battery in situ with the existing technology. Recently, some scholars have fabricated a functional transparent battery, which is beneficial to the basic research of batteries. However, the energy density of this transparent battery is lower than that of ordinary lithium batteries, and its application range is limited. CN104037388A also discloses a transparent battery, which proposes a transparent or translucent holder having at least one electrode material with one or more internal structures, and then deposits a transparent or translucent conductive film according to the shape of the holder, Positive and negative materials are deposited on the conductive film, and the positive and negative materials are separated by a solid electrolyte. The operability of this battery is not strong, and it can only be used as a functional battery, and its commercial application is limited.

Therefore, it is necessary to propose a new visualized Li-ion electrode and battery.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a visualized lithium ion electrode and application and a visualized lithium ion battery in view of the deficiencies of the prior art. The visualized lithium ion battery of the present invention can observe the structure change, color change, gas production and lithium precipitation of the positive electrode or negative electrode material in the electrochemical reaction process in the battery charging and discharging process in situ.

In order to achieve the above object, a first aspect of the present invention provides a visualized lithium ion electrode, which includes a transparent current collector film and a negative electrode active material or a positive electrode active material coated on the surface of the transparent current collector film.

The second aspect of the present invention provides the application of the visualized lithium ion electrode in a lithium ion battery.

A third aspect of the present invention provides a visualized lithium-ion battery, the battery includes one or more sets of positive electrodes and negative electrodes, an electrolyte, and a celgad separator spaced between the positive electrodes and the negative electrodes; the positive electrodes and the negative electrodes All are the above-mentioned visible lithium ion electrodes; the encapsulation of the lithium ion battery is to use a transparent battery encapsulation film for full encapsulation, or, after encapsulation with an aluminum-plastic film, a window is opened on the aluminum-plastic film, and the The window portion is encapsulated with the transparent battery encapsulation film.

A fourth aspect of the present invention provides a visualized lithium-ion battery, the battery includes one or more sets of positive electrodes and negative electrodes, an electrolyte and a separator spaced between the positive electrodes and the negative electrodes; the negative electrodes are composed of non-visualized electrodes. The lithium ion negative electrode and the visible lithium ion negative electrode are composed, and the positive electrode is a non-visual lithium ion positive electrode; after the non-visual lithium ion negative electrode and the non-visual lithium ion positive electrode are cross-laminated, the electrode group after the cross-lamination is cross-laminated. The visualized lithium ion negative electrodes are arranged on both sides, and the diaphragm between the cross-laminated electrode group and the visualized lithium ion negative electrode is a celgad diaphragm; Or, after the aluminum-plastic film is used for packaging, a window is opened on the aluminum-plastic film, and the transparent battery packaging film is used for packaging at the window portion.

The technical scheme of the present invention has the following beneficial effects:

(1) The visualized lithium ion battery of the present invention can observe the structure change, color change, gas production and lithium precipitation of the positive electrode or negative electrode material in the electrochemical reaction process during the charging and discharging process of the battery in situ, and does not affect the battery energy. density.

(2) The visualized lithium ion electrode of the present invention can be applied to general lithium ion batteries for safety warning.

(3) The visualized lithium-ion battery of the present invention can be applied to electrochemical mechanism research and lithium precipitation research, and can also be applied to the field of 3C.

Other features and advantages of the present invention will be described in detail in the detailed description that follows.

Description of drawings

The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of the exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the exemplary embodiments of the present invention. same parts.

FIG. 1 shows a schematic diagram of a visualized lithium-ion battery and electrodes provided in Embodiment 1 of the present invention.

FIG. 2 shows a charging capacity (Capacity (Ah))-voltage (Voltage (V)) diagram of a visualized lithium-ion battery provided in Embodiment 1 of the present invention during pre-charging and non-evacuating charging.

FIG. 3 shows an ICA diagram for visualizing the charging process of a lithium-ion battery during pre-charging and gas-pumping and without gas-pumping according to Embodiment 1 of the present invention. (The abscissa Voltage represents the voltage, and the ordinate dQ/dV/AhV ^-1 represents the voltage plateau change)

FIG. 4 shows a graph of uniform lithium deposition on the surface of the positive electrode of a visualized lithium-ion battery provided in Example 1 of the present invention after the battery is disassembled after being charged without air extraction.

FIG. 5 shows a schematic diagram of a 3Ah composite pole piece visualized lithium ion battery and electrodes provided in Example 2 of the present invention.

6 shows a comparison diagram of EIS (electrochemical impedance spectroscopy) of a 3Ah composite electrode visible lithium ion battery provided in Example 2 of the present invention and a non-visualized lithium ion battery provided in Comparative Example 1.

Fig. 7(a) shows a 3Ah composite pole piece visual lithium ion battery provided in Example 2 of the present invention and a non-visual lithium ion battery provided in Comparative Example 1 in (DIS (discharge)-DOD (discharge state) ) HPPC power (P/W) comparison chart.

Figure 7(b) shows a 3Ah composite pole piece visual lithium ion battery provided in Example 2 of the present invention and a non-visual lithium ion battery provided in Comparative Example 1 in (CHA (charge)-DOD (discharge state) ) HPPC power (P/W) comparison chart.

FIG. 8 shows an optical microscope image before charging of a 3Ah composite pole piece visualized lithium ion battery provided in Example 2 of the present invention.

FIG. 9 shows an optical microscope image of a fully charged state of a 3Ah composite pole piece visualized after charging of the lithium ion battery provided in Example 2 of the present invention.

FIG. 10 shows a schematic diagram of a visualized lithium ion battery and electrodes provided in Embodiment 3 of the present invention.

The reference numerals are explained as follows:

1- Visualize Li-ion battery;

11- Visualize the lithium ion negative electrode;

12- Visualize the lithium ion positive electrode;

111 - Visualize the active material layer of the lithium ion negative electrode;

112- Visualize the current collector of the lithium ion negative electrode;

113- visualize the negative lug of the lithium ion negative electrode;

121 - Visualize the active material layer of the lithium-ion cathode;

122 - Visualize the current collector of the lithium-ion cathode;

123- Visualize the positive lug of the lithium-ion positive electrode;

2-3Ah composite pole piece visualized lithium-ion battery;

23- Visualize the lithium ion negative electrode;

24-Non-visualized lithium-ion positive electrode;

25-Non-visualized lithium ion negative electrode;

231 - Visualize the active material layer of the lithium ion negative electrode;

232 - Visualize the current collector of the lithium ion anode;

241-active material layer of non-visualized lithium ion positive electrode;

242 - Current collectors for non-visualized lithium-ion cathodes;

251-active material layer of non-visualized lithium ion negative electrode;

252 - Current collectors for non-visualized lithium ion anodes;

3- Visualization of Li-ion battery;

31-Visible Li-ion negative electrode coated on both sides;

32-Visible Li-ion cathode coated on both sides;

33-Visible lithium ion negative electrode coated on one side;

311 - The active material layer of the double-sided coated visualized lithium-ion positive electrode;

321 - the negative lug of the double-sided coated visualized Li-ion negative electrode;

322 - The positive lug of the double-sided coated visualized Li-ion positive electrode;

331 - Active material layer of a single-sided coated visualized Li-ion anode.

Detailed ways

Preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention are described below, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.

A first aspect of the present invention provides a visualized lithium ion electrode, which includes a transparent current collector film and a negative electrode active material or a positive electrode active material coated on the surface of the transparent current collector film.

In the present invention, the transparent current collector film is a conductive, acid-resistant and electrochemical corrosion-resistant transparent current collector film. As a preferred solution, the transparent current collector film is selected from metal films with a thickness of 8-12 nm Oxide films with a thickness of 0.01-500 μm or polymer films with a thickness of 0.01-500 μm.

According to the present invention, preferably,

The metal film is selected from Au thin film, Ag thin film, Pt thin film, Cu thin film or Al thin film;

The oxide film is selected from In2O3 film, In2O3:Sn film, SnO2 film, ZnO film, ZnO:In(IZO) film, ZnO:Ga film, ZnO:Al film or CdO film;

The polymer film is selected from a poly3,4-alkylene dioxythiophene film, a poly3,4-ethylenedioxythiophene film or a polystyrene sulfonic acid film.

According to the present invention, preferably, the active material is single-sided or double-coated on the surface of the transparent current collector film.

In the present invention, the single-sided coating can observe the embedded state of lithium ions on the surface of the transparent current collector film, and can also observe the electrochemical state of the visualized lithium ion electrode according to the color change. .

According to the present invention, preferably, the step of coating the active material on the surface of the transparent current collector film includes: forming a plurality of grooves of the same size on the surface of the transparent current collector film, and coating the active material on the surface of its transparent current collector film.

In the present invention, the groove is an etching groove or a concave-convex groove formed by etching, printing and other processes according to the material requirements of the transparent conductive film; the groove can not only increase the negative electrode active material or the positive electrode active material in the The adhesion on the transparent conductive film can also reduce the quality of the transparent conductive film and improve the energy density of the electrode.

According to the present invention, preferably, the depth and width of the groove are both 0.02-0.05 times the thickness of the transparent current collector film.

According to the present invention, preferably,

The negative electrode active material is at least one of lithium titanate, graphite, silicon oxygen and silicon carbon;

The positive active material is at least one of lithium manganate, lithium cobaltate, lithium iron phosphate and lithium nickel cobalt manganate.

The second aspect of the present invention provides the application of the visualized lithium ion electrode in a lithium ion battery.

A third aspect of the present invention provides a visualized lithium-ion battery, the battery includes one or more sets of positive electrodes and negative electrodes, an electrolyte, and a celgad separator spaced between the positive electrodes and the negative electrodes; the positive electrodes and the negative electrodes All are the above-mentioned visible lithium ion electrodes; the encapsulation of the lithium ion battery is to use a transparent battery encapsulation film for full encapsulation, or, after encapsulation with an aluminum-plastic film, a window is opened on the aluminum-plastic film, and the The window portion is encapsulated with the transparent battery encapsulation film.

A fourth aspect of the present invention provides a visualized lithium-ion battery, the battery includes one or more sets of positive electrodes and negative electrodes, an electrolyte and a separator spaced between the positive electrodes and the negative electrodes; the negative electrodes are composed of non-visualized electrodes. The lithium ion negative electrode and the visible lithium ion negative electrode are composed, and the positive electrode is a non-visual lithium ion positive electrode; after the non-visual lithium ion negative electrode and the non-visual lithium ion positive electrode are cross-laminated, the electrode group after the cross-lamination is cross-laminated. The visualized lithium ion negative electrodes are arranged on both sides, and the diaphragm between the cross-laminated electrode group and the visualized lithium ion negative electrode is a celgad diaphragm; Or, after the aluminum-plastic film is used for packaging, a window is opened on the aluminum-plastic film, and the transparent battery packaging film is used for packaging at the window portion.

In the present invention, the transparent battery packaging film is a transparent battery packaging film that is resistant to high temperature, acid, insulation and pressure. As a preferred solution, the transparent battery packaging film is a transparent polyimide film, polyester film, polyamide film At least one of an imide film, a polyetherimide film, and a thermoplastic polyurethane film.

The present invention will be specifically described below by way of examples.

Example 1

This embodiment is used to illustrate the visualized lithium ion positive electrode, the visualized lithium ion negative electrode, and the visualized lithium ion battery of the present invention.

The current collector 122 of the visible lithium ion positive electrode 12 is an In ₂ O ₃ :Sn film (ITO) with a thickness of 100 μm, and the positive electrode tabs 123 are reserved; the transparent current collector 122 film needs to be coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ A plurality of grooves with a depth of 5 μm and a width of 5 μm were etched on the surface of the positive electrode active material 121 , and the positive electrode active material 121 was single-coated on the surface of the transparent current collector 122 film with the grooves, and a vacuum oven at 70° C. After baking for 24 hours, a visualized lithium-ion positive electrode 12 was formed, as shown in FIG. 1 .

The current collector 112 of the visualized lithium ion negative electrode 11 is an In ₂ O ₃ :Sn film (ITO) with a thickness of 100 μm, and the negative electrode ears 113 are reserved; the transparent current collector 112 film needs to be coated with a graphite negative electrode active material 111. A plurality of grooves with a depth of 5 μm and a width of 5 μm were etched, and the negative electrode active material 111 was single-coated on the surface of the transparent current collector 112 film with the grooves, and dried in a vacuum oven at 70°C for 24 hours to form visualized lithium ions The negative electrode 11 is shown in FIG. 1 .

The visualized lithium ion battery 1 includes a set of the above-mentioned visualized lithium ion positive electrode 12 and visualized lithium ion negative electrode 11, and the diaphragm between the above-mentioned visualized lithium ion positive electrode 12 and visualized lithium ion negative electrode 11 is a celgad diaphragm; The corroded tape fixes the above-mentioned visible lithium ion positive electrode 12, celgad diaphragm, and visible lithium ion negative electrode 11 to form a battery cell, which is dried in a vacuum oven at 70°C for 24 hours with a transparent polyimide film (PIC) to pass through. Fully encapsulated by hot pressing, vacuum pumped at the same time, and electrolyte injected to obtain the visualized lithium ion battery 1, as shown in FIG. 1 .

Example 2

This embodiment provides a 3Ah composite pole piece visible lithium ion battery 2 , the battery 2 includes 11 double-coated non-visual lithium ion positive electrodes 24 and 10 double-sided coated non-visual lithium ion negative electrodes 25 and 2 A single-sided visible lithium ion negative electrode 23;

The current collector 242 of the non-visualized lithium ion positive electrode is aluminum foil, and the positive electrode active material 241 is LiNi _0.5 Co _0.2 Mn _0.3 O ₂ ;

The current collector 252 of the non-visual lithium ion negative electrode is copper foil, and the negative electrode active material 251 is graphite;

The visualized lithium ion negative electrode is the same as that of Example 1.

After the non-visible lithium ion negative electrode 25 and the non-visible lithium ion positive electrode 24 are cross-laminated, the visible lithium-ion negative electrode 23 is arranged on both sides of the cross-laminated electrode group, and the cross-laminated electrode group is The diaphragm with the visualized lithium ion negative electrode 23 is a celgad diaphragm;

The battery cell composed of the above electrodes was dried in a vacuum oven at 70°C for 24 hours and then fully encapsulated with a transparent polyimide film (PIC) by hot pressing, vacuumed at the same time, and injected with electrolyte to obtain the 3Ah composite pole piece Visualize Li-ion battery 2.

Example 3

This embodiment provides a visualized lithium ion battery 3 , and the battery 3 includes one double-sided coated visualized lithium ion negative electrode 31 , two double-sided coated visualized lithium ion positive electrodes 32 and two double-sided coated visualized lithium ion positive electrodes 32 are the same as those in Embodiment 1. The single-sided coated visualized lithium ion negative electrode 33;

The step of double-side coating is to coat the same active material on the other side of the single-side-coated visualized lithium ion electrode.

Place the double-coated visualized lithium ion negative electrode 31 between the two double-sided coated visualized lithium ion positive electrodes 32, and place the two single-sided coated visualized lithium ion anodes 32 that are the same as in Example 1. The negative electrode 33 is placed on both sides of the visible lithium ion positive electrode 32 coated on both sides, and the diaphragm between the electrodes is a celgad diaphragm;

The battery cell composed of the above-mentioned electrodes is fully packaged with a transparent polyimide film (PIC) by hot pressing after being dried in a vacuum oven at 70°C for 24 hours, and at the same time, vacuumed and injected with an electrolyte to obtain the visualized lithium-ion battery. 3, as shown in Figure 10.

Comparative Example 1

This comparative example provides a non-visualized lithium-ion battery, the battery includes 11 sheets of the same double-sided coated non-visual lithium ion positive electrode as in Example 2 and 13 sheets of the same double-sided coated non-visualized lithium ion positive electrode as in Example 2 For the lithium ion negative electrode, the battery cell composed of the above-mentioned electrodes was dried in a vacuum oven at 70°C for 24 hours and then fully packaged with aluminum-plastic film by hot pressing, vacuumed at the same time, and injected with electrolyte to obtain the non-visual lithium ion battery.

Test Example 1

Take two visualized lithium-ion batteries 1 prepared in Example 1, and perform tubular pre-charging on one of the visualized lithium-ion batteries. During the tubular pre-charging process, nitrogen gas is always evacuated. In this process, it can be observed that the negative electrode active material is charged by Black turns brown to yellow, and the color reverses when discharged. The other visualized lithium-ion battery was pre-charged without nitrogen gas extraction. During this process, it can be observed that with the charging process, when the battery is charged to a certain extent, the battery begins to swell, and the negative current collector surface of the visualized lithium-ion battery is not seen. Color changes.

It can be seen from Figure 2 that the charge and discharge capacities of the above two visualized lithium-ion batteries are equivalent.

It can be seen from Figure 3 that the voltage platforms of the above two visualized lithium-ion batteries are quite different.

It can be seen from Fig. 4 that the pre-charged visualized lithium-ion battery without nitrogen gas extraction found that lithium was uniformly deposited on the surface of the positive electrode after the battery was disassembled.

Test case 2

The EIS and HPPC tests were performed on the 3Ah composite pole piece visualized lithium-ion battery 2 of Example 2 and the non-visualized lithium-ion battery of Comparative Example 1, and the test results are shown in FIG. 6 and FIG. 7 . It can be seen from FIG. 6 that the difference in the internal resistance of the batteries between Example 2 and Comparative Example 1 is small; as can be seen from FIG. 7 , the difference in battery power between Example 2 and Comparative Example 1 is small.

In this test example, optical microscope photographs were taken of the fully charged state of the 3Ah composite pole piece visualized lithium-ion battery 2 of Example 2 before and after charging, respectively, as shown in FIG. 8 and FIG. 9 . From FIG. 8 and FIG. 9 , it can be observed that the 3Ah composite pole piece of Example 2 visualizes the bright yellow lithium ions in the negative section of the lithium ion battery 2 after charging.

Various embodiments of the present invention have been described above, and the foregoing descriptions are exemplary, not exhaustive, and not limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims (10)

1. A visualized lithium ion electrode, characterized in that the electrode comprises a transparent current collector film and a negative electrode active material or a positive electrode active material coated on the surface of the transparent current collector film. 2. The visualized lithium ion electrode of claim 1, wherein, The transparent current collector thin film is selected from a metal film system with a thickness of 8-12 nm, an oxide film system with a thickness of 0.01-500 μm or a polymer film system with a thickness of 0.01-500 μm. 3. The visualized lithium-ion electrode of claim 2, wherein, The metal film is selected from Au thin film, Ag thin film, Pt thin film, Cu thin film or Al thin film; The oxide film is selected from In2O3 film, In2O3:Sn film, SnO2 film, ZnO film, ZnO:In(IZO) film, ZnO:Ga film, ZnO:Al film or CdO film; The polymer film is selected from a poly3,4-alkylene dioxythiophene film, a poly3,4-ethylenedioxythiophene film or a polystyrene sulfonic acid film. 4. The visualized lithium-ion electrode of claim 1, wherein, The active material is single-sided or double-coated on the surface of the transparent current collector film; The step of coating the active material on the surface of the transparent current collector film includes: forming a plurality of grooves of the same size on the surface of the transparent current collector film, and coating the active material on the surface of the transparent current collector film. surface. 5. The visualized lithium ion electrode according to claim 4, wherein the depth and width of the trench are both 0.02-0.05 times the thickness of the transparent current collector film. 6. The visualized lithium-ion electrode of claim 1, wherein, The negative electrode active material is at least one of lithium titanate, graphite, silicon oxygen and silicon carbon; The positive active material is at least one of lithium manganate, lithium cobaltate, lithium iron phosphate and lithium nickel cobalt manganate. 7. The application of the visualized lithium-ion electrode according to claims 1-6 in a lithium-ion battery. 8. A visualized lithium ion battery, characterized in that the battery comprises one or more groups of positive electrodes and negative electrodes, an electrolyte, and a celgad separator spaced between the positive electrodes and the negative electrodes; the positive electrodes and the negative electrodes are both It is the visible lithium ion electrode according to any one of claims 1 to 6; the encapsulation of the lithium ion battery is to use a transparent battery packaging film for full packaging, or, after packaging with an aluminum plastic film, the aluminum plastic film is used for packaging. A window is opened on the film, and the transparent battery packaging film is used to encapsulate the window portion. 9. A visualized lithium-ion battery, characterized in that the battery comprises one or more sets of positive electrodes and negative electrodes, an electrolyte and a separator spaced between the positive electrodes and the negative electrodes; the negative electrodes are made of non-visual lithium ion batteries. The ion negative electrode is composed of the visualized lithium ion negative electrode according to any one of claims 1-6, the positive electrode is a non-visual lithium ion positive electrode; The visualized lithium ion negative electrodes are arranged on both sides of the cross-laminated electrode group, and the diaphragm between the cross-laminated electrode group and the visualized lithium ion negative electrode is a celgad diaphragm; the lithium ion battery is packaged by using The transparent battery encapsulation film is fully encapsulated, or, after encapsulation with an aluminum-plastic film, a window is opened on the aluminum-plastic film, and the transparent battery encapsulation film is used for encapsulation in the window portion. 10. The visualized lithium-ion battery according to claim 8 or 9, wherein the transparent battery packaging film is a transparent polyimide film, polyester film, polyamideimide film, polyetherimide film and At least one of thermoplastic polyurethane films.

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