TW202005158A - lithium battery - Google Patents

Abstract

A lithium is provided and includes a cathode material, an anode material, and an electrolyte. The electrolyte is disposed between the cathode material and the anode material, and the electrolyte includes a lithium ion component and N-vinylmethylenamine.

Description

lithium battery

The invention relates to a battery, especially to a lithium battery.

In recent years, lithium batteries have been widely used in various electronic products, electric steam locomotives, or energy storage devices. Therefore, the focus of many researches is on improving the efficiency, energy density and safety of lithium batteries.

However, the lithium battery still needs to consider many parts, for example, through the choice of materials to improve the characteristics of the lithium battery, so that the electrical properties of the lithium battery can be further developed.

Therefore, it is necessary to provide a lithium battery to solve the problems existing in the conventional technology.

An object of the present invention is to provide a lithium battery which adds a specific material to the electrolyte to increase the potential window of the lithium battery, thereby improving the application degree of the lithium battery.

To achieve the above object, the present invention provides a lithium battery including: a positive electrode material and a negative electrode material; and an electrolyte disposed between the positive electrode material and the negative electrode material, wherein the electrolyte contains a lithium ion component and N -Ethylene methylamide.

In an embodiment of the invention, a separator is further included between the positive electrode material and the negative electrode material, wherein the electrolyte is a liquid electrolyte.

In one embodiment of the invention, the electrolyte is a colloidal electrolyte.

In one embodiment of the invention, the colloidal electrolyte contains a liquid water.

In one embodiment of the present invention, based on the total weight of the colloidal electrolyte being 100 wt%, the liquid water system is between 6 wt% and 14.3 wt%.

In one embodiment of the present invention, a weight ratio of the N-vinylformamide to the lithium ion component is between 0.1 and 0.5.

In one embodiment of the present invention, a positive electrode binder is further included for bonding the positive electrode material.

In one embodiment of the present invention, the positive electrode binder includes N-vinylformamide.

In one embodiment of the present invention, the positive electrode material includes at least one of lithium cobalt oxide, ternary material, and lithium iron phosphate.

In one embodiment of the present invention, the negative electrode material includes at least one of graphite, lithium titanyl oxide, and lithium metal.

10‧‧‧Lithium battery

11‧‧‧ Cathode material

12‧‧‧Anode material

13‧‧‧ electrolyte

14‧‧‧ isolation film

15‧‧‧Hollow shell

Figure 1A: A schematic cross-sectional view of a lithium battery according to an embodiment of the present invention.

FIG. 1B: A schematic cross-sectional view of a lithium battery according to another embodiment of the invention.

Figure 2: The test data graph of the lithium battery at a potential window of about 25 degrees Celsius according to an embodiment of the present invention.

Figure 3: Experimental data graphs of the ionic conductivity of colloidal electrolytes according to various embodiments of the present invention.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the preferred embodiments of the present invention will be specifically described below in conjunction with the accompanying drawings, which will be described in detail below. Furthermore, the terms of direction mentioned in the present invention, such as up, down, top, bottom, front, back, left, right, inner, outer, side, surrounding, center, horizontal, horizontal, vertical, longitudinal, axial, The radial direction, the uppermost layer or the lowermost layer, etc., are only the directions referring to the attached drawings. Therefore, the directional terminology is used to illustrate and understand the present invention, not to limit the present invention.

Please refer to FIGS. 1A and 1B. FIG. 1A is a schematic cross-sectional view of a lithium battery 10 according to an embodiment of the present invention; and FIG. 1B is a schematic cross-sectional view of a lithium battery 10 according to another embodiment of the present invention. A lithium battery 10 according to an embodiment of the present invention mainly includes a positive electrode material 11, a negative electrode material 12, and an electrolyte 13. In one embodiment, the positive electrode material mainly serves as a positive electrode, and may include at least one of lithium cobalt oxide, ternary material, and lithium iron phosphate. In an exemplary embodiment, the ternary material is, for example, Li(Ni _x Mn _y Co _z )O ₂ , where x+y+z=1, and Li(Ni _x Mn _y Co _z )O ₂ may be simply referred to as NMC. In another embodiment, a positive electrode adhesive can be used to bond the positive electrode material 11 itself into a block. In an exemplary embodiment, the positive electrode binder may include N-vinylformamide. As the positive electrode binder, N-vinylformamide may use only liquid water as a dispersant, which can avoid the problem of environmental pollution caused by the use of organic solvents. .

The negative electrode material 12 of the lithium battery 10 of the embodiment of the present invention is mainly used as a negative electrode, and may include at least one of graphite, lithium metal, and lithium titanate (or lithium titanate; LTO; for example, the chemical formula may be Li ₄ Ti ₅ O ₁₂ ) . Among the above-mentioned negative electrode materials, lithium titanyl oxide can be used as a negative electrode material in lithium batteries using an aqueous electrolyte (liquid electrolyte).

The electrolyte 13 of the lithium battery 10 of the embodiment of the present invention is provided between the positive electrode material 11 and the negative electrode material 12, wherein the electrolyte contains a lithium ion component and N-vinylformamide. In one embodiment, the lithium ion component includes, for example, at least one of lithium bistrifluoromethanesulfonylimide (LITFSI), LiPF ₆ , LiClO ₄ , LiSO _4, and LiBF ₄ . In another embodiment, the weight ratio of the N-vinylformamide to the lithium ion component is between 0.1 and 0.5, such as 0.2, 0.25, 0.3, 0.35, 0.4, or 0.45.

It should also be mentioned that an object of the embodiments of the present invention is to expand the range of the potential window (for example, a range of about 5 volts) by adding specific substances (such as N-vinylformamide) to the electrolyte. Furthermore, the application of the lithium battery is increased.

In an embodiment, the electrolyte 13 may be various forms of electrolyte, for example, the electrolyte is a colloidal electrolyte. In the case of using the colloidal electrolyte, there is no need to provide a separator (as shown in Figure 1A); or the electrolyte 13 is a liquid electrolyte (usually a liquid electrolyte is an organic liquid), and the lithium battery 10 further includes a separator 14, between the positive electrode material 11 and the negative electrode material 12, wherein the liquid electrolyte is filled between the positive electrode material 11 and the separator 14 and between the negative electrode material 12 and the separator 14 ( (As shown in Figure 1B).

In one embodiment, the colloidal electrolyte may include a liquid water. In a specific example, based on the total weight of the colloidal electrolyte being 100wt%, the liquid water system is between 6wt% and 14.3wt%, such as 6.1wt%, 6.5wt%, 6.7wt%, 6.9wt %, 7wt%, 8wt%, 9wt%, 9.4wt%, 10wt%, 10.4wt%, 11wt%, 12wt%, 13wt%, 13.7wt% or 14wt%. It should be mentioned that the lower the weight percentage of the liquid water, the higher the hardness, and the higher the weight percentage of the liquid water, the better the ionic conductivity.

In an embodiment, the positive electrode material 11, the negative electrode material 12 and the electrolyte 13 can be loaded in a hollow casing 15.

The following will specifically explain that the lithium battery according to the embodiment of the present invention can increase the range of the potential window of the lithium battery by adding a specific material to the electrolyte.

Please refer to FIG. 2, which is a test data graph of a lithium battery at a potential window of about 25 degrees Celsius according to an embodiment of the present invention. The lithium battery used in FIG. 2 includes two embodiments, in which a weight ratio of the N-vinylformamide to the lithium ion component of the electrolyte 13 is 2:8 (that is, the weight ratio is 0.25). In addition, the electrolyte 13 is a colloidal electrolyte, and contains liquid water, where the total weight of the colloidal electrolyte is 100 wt%, the liquid water in these two embodiments is 7.4 wt% (corresponding to Example 1) and 14wt% (corresponding to example 2). It can be seen from FIG. 2 that for the 7.4wt% embodiment, the range of the potential window is about 5 volts (based on the upper X axis as a reference, roughly ranging from -2V to 3V), while for the 14wt% embodiment, The range of the potential window is about 4 volts (based on the upper X-axis, roughly ranging from -1V to 3V). Compared with the existing aqueous lithium battery (potential window is only 3.0 volts), the lithium battery according to an embodiment of the present invention can indeed increase the range of the potential window of the lithium battery by adding a specific material to the electrolyte.

It is worth mentioning that the method of making the above potential window test data mainly refers to the following documents: "Water-in-Salt" electrolyte enabled LiMn ₂ O ₄ /TiS ₂ Lithium-ion batteries; Wei Sun et al.; Electrochemistry Communication 82 (2017); pages 71-74". This document is the measurement of the potential window of the colloidal electrolyte through the tripolar electrode. The experimental data obtained in Figure 2 is the use of commercially available stainless steel bipolar electrode, Measuring instrument (electrochemical impedance analyzer; model CHI6116E; CH Instruments, USA) instead of a three-electrode electrode. Therefore, when performing the experimental measurements in Figure 2, first use commercially available electrodes to prepare the The electrolyte measures the potential window to obtain a standard potential, and then standardizes the potential data of the upper X axis and the lower X axis in Figure 2. For example, although it is measured as zero potential (lower X axis) in the literature However, with a commercially available electrode, a potential of about -4 volts (upper X axis) is measured. Therefore, the potential measurement value of the two can be converted in this way.

On the other hand, please refer to FIG. 3, which is a graph of experimental data of the ionic conductivity of colloidal electrolytes in various embodiments of the present invention, where PNVF refers to N-vinylformamide and LiTFSI refers to the use of Lithium bistrifluoromethylsulfonylimide as a lithium ion component, H ₂ O refers to liquid water; and PNVF: LiTFSI refers to the weight of N-vinylformamide and lithium bistrifluoromethylsulfonylimide proportion. It can be seen from the figure that most of the colloidal electrolytes can obtain properties close to that of commercial electrolytes at room temperature (that is, the position where 1000/T is about 3.4) (the ionic conductivity of commercial electrolytes is about 10 ^-3 S/cm, The logarithmic value is about -3. For an embodiment where H ₂ O is 6wt%, it can also have properties close to that of a commercial electrolyte at 50 to 60 degrees Celsius.

In addition, it is worth mentioning that N-vinylformamide can also be used as a positive electrode binder. Compared with the commonly used polyvinylidene fluoride (adhesion strength is about 0.8N), N-vinylformamide Amine has better adhesion effect (adhesion strength is about 2.5N).

Although the present invention has been disclosed in preferred embodiments, it is not intended to limit the present invention. Anyone who is familiar with this skill can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be as defined in the scope of the attached patent application.

Claims (10)

A lithium battery includes: a positive electrode material and a negative electrode material; and an electrolyte disposed between the positive electrode material and the negative electrode material, wherein the electrolyte includes a lithium ion component and N-vinylformamide. The lithium battery as described in item 1 of the patent application scope further includes a separator disposed between the positive electrode material and the negative electrode material, wherein the electrolyte is a liquid electrolyte. The lithium battery as described in item 1 of the patent application scope, wherein the electrolyte is a colloidal electrolyte. The lithium battery as described in item 3 of the patent application scope, wherein the colloidal electrolyte contains a liquid water. The lithium battery as described in item 4 of the patent application, wherein the liquid aqueous system is between 6wt% and 14.3wt% based on the total weight of the colloidal electrolyte being 100wt%. The lithium battery as described in item 1 of the patent application range, wherein a weight ratio of the N-vinylformamide to the lithium ion component is between 0.1 and 0.5. The lithium battery as described in item 1 of the patent application scope further includes a positive electrode binder for binding the positive electrode material. The lithium battery as described in item 7 of the patent application range, wherein the positive electrode binder contains N-vinylformamide. The lithium battery as described in item 1 of the patent application range, wherein the positive electrode material includes at least one of lithium cobalt oxide, ternary material, and lithium iron phosphate. The lithium battery as described in item 1 of the patent application range, wherein the negative electrode material includes at least one of graphite, lithium titanium oxide, and lithium metal.

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