TWI675503B - lithium battery - Google Patents

Abstract

A lithium battery includes: a positive electrode material, 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-vinylmethanamine.

Description

lithium battery

The invention relates to a battery, in particular to a lithium battery.

In recent years, lithium batteries have been widely used in various electronic products, electric vehicles, or energy storage devices. Therefore, the focus of many studies is to improve the efficiency, energy density, and safety of lithium batteries.

However, there are still many parts that need to be considered for lithium batteries, such as improving the characteristics of lithium batteries through the choice of materials, so that the electrical properties of lithium batteries can be further grown.

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

An object of the present invention is to provide a lithium battery, which is made by adding a specific material to an electrolyte, so as 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 provided between the positive electrode material and the negative electrode material, wherein the electrolyte includes a lithium ion component and N -Vinylformamide.

In an embodiment of the present 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 present invention, the electrolyte is a colloidal electrolyte.

In one embodiment of the present invention, the colloidal electrolyte includes liquid water.

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

In one embodiment of the present invention, a weight ratio of the N-vinylformamide and 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 adhesive includes N-vinylformamide.

In one embodiment of the present invention, the cathode material includes at least one of lithium cobaltate, ternary material, and lithium iron phosphate.

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

10‧‧‧ lithium battery

11‧‧‧ cathode material

12‧‧‧ Negative electrode material

13‧‧‧ Electrolyte

14‧‧‧ isolation film

15‧‧‧ hollow shell

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

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

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

FIG. 3 is a graph of experimental data of the ionic conductivity of the colloidal electrolyte in 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 following describes the preferred embodiments of the present invention and the accompanying drawings in detail, as follows. Furthermore, the directional terms mentioned in the present invention include, for example, top, bottom, top, bottom, front, back, left, right, inside, outside, side, periphery, center, horizontal, horizontal, vertical, vertical, axial, The radial direction, the uppermost layer, or the lowermost layer, etc., are only directions referring to the attached drawings. Therefore, the directional terms used are for explaining and understanding the present invention, but not for limiting the present invention.

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 cross-sectional schematic view of a lithium battery 10 according to another embodiment of the present invention. The 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 is mainly used as a positive electrode, and may include at least one of lithium cobaltate, a 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 adhesive may include N-vinylformamide, and N-vinylformamide as the positive electrode adhesive may use only liquid water as a dispersant, thereby avoiding environmental pollution caused by using organic solvents .

The negative electrode material 12 of the lithium battery 10 according to 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 titanium oxide (also called lithium titanate; LTO; for example, the chemical formula may be Li ₄ Ti ₅ O ₁₂ ). . Among the above-mentioned negative electrode materials, lithium titanium oxide can be suitably used as a negative electrode material for a lithium battery using an aqueous electrolyte (liquid electrolyte).

The electrolyte 13 of the lithium battery 10 according to the embodiment of the present invention is disposed between the positive electrode material 11 and the negative electrode material 12, wherein the electrolyte includes a lithium ion component and N-vinylmethanamine. 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, a 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 embodiment of the present invention is to increase the range of the potential window (for example, a range of about 5 volts) by adding a specific substance (such as N-vinylformamide) to the electrolyte, Further increase the application of the lithium battery.

In one embodiment, the electrolyte 13 may be an electrolyte in various forms, for example, the electrolyte is a gel electrolyte. In the case of using the colloidal electrolyte, there is no need to provide a separator (such as FIG. 1A); or the electrolyte 13 is a liquid electrolyte (usually the liquid electrolyte is an organic liquid), and the lithium battery 10 further includes a separator 14. It is disposed 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 Charged between the negative electrode material 12 and the separator 14 (as shown in FIG. 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 100 wt%, the liquid water system is between 6 wt% and 14.3 wt%, such as 6.1 wt%, 6.5% wt, 6.7% wt, and 6.9 wt%. %, 7 wt%, 8 wt%, 9 wt%, 9.4 wt%, 10 wt%, 10.4 wt%, 11 wt%, 12 wt%, 13 wt%, 13.7 wt%, or 14 wt%. 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 one embodiment, the positive electrode material 11, the negative electrode material 12 and the electrolyte 13 can be loaded in a hollow case 15.

The lithium battery of the embodiment of the present invention will be described in detail below by adding a specific material to the electrolyte to increase the range of the potential window of the lithium battery.

Please refer to FIG. 2, which is a graph of test data 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 and 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. Based on the total weight of the colloidal electrolyte being 100% by weight, the liquid water in the two embodiments is 7.4% by weight (corresponding to Example 1) and 14wt% (corresponding to Example 2). It can be seen from FIG. 2 that for the 7.4 wt% embodiment, the range of the potential window is about 5 volts (based on the upper X-axis, and the range is approximately -2 V to 3 V), and for the 14 wt% embodiment, the 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 (the potential window is only 3.0 volts), the lithium battery of one 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 above-mentioned method of making the 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 measures the potential window of a colloidal electrolyte through a three-pole electrode. The experimental data obtained in Figure 2 is a commercially available stainless steel two-pole electrode. Measuring instrument (electrochemical impedance analyzer; model CHI6116E; American CH Instruments) instead of a three-pole electrode. Therefore, in the experimental measurement shown in Figure 2, the commercially available electrode was first used against the above-mentioned literature. The electrolyte performs the measurement of the potential window to obtain a standard potential, and then normalizes the potential data of the upper X axis and the lower X axis in Figure 2. For example, although it was measured as a zero potential (lower X axis) in the literature However, with a commercially available electrode, a potential of about -4 volts (the upper X axis) is measured. Therefore, the potential measurement values of both can be converted by this method.

On the other hand, please refer to FIG. 3, which is an experimental data chart of the ionic conductivity of the colloidal electrolyte in various embodiments of the present invention, in which PPVF refers to N-vinylformamide and LiTFSI refers to the use of Lithium bistrifluoromethanesulfonimide as a lithium ion component, H ₂ O refers to liquid water; and PNVF: LiTFSI refers to the weight of N-vinylformamide and lithium bistrifluoromethanesulfonimide proportion. As can be seen from the figure, most colloidal electrolytes can obtain properties close to commercial electrolytes at room temperature (ie, 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 in which H ₂ O is 6 wt%, it can also have properties close to commercial electrolytes at 50 to 60 degrees Celsius.

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

Although the present invention has been disclosed in a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. The scope of protection shall be determined by the scope of the attached patent application.

Claims (5)

A lithium battery includes: a positive electrode material and a negative electrode material; and a colloidal electrolyte disposed between the positive electrode material and the negative electrode material, wherein the colloidal electrolyte includes a liquid water, a lithium ion component, and N- Ethylmethylformamide, wherein the total weight of the colloidal electrolyte is 100% by weight, the liquid water system is between 6% and 14.3% by weight, and one weight of the N-vinylformamide and the lithium ion component The ratio is between 0.1 and 0.5. The lithium battery described in item 1 of the patent application scope further includes a positive electrode adhesive for adhering the positive electrode material. The lithium battery according to item 2 of the patent application scope, wherein the positive electrode adhesive comprises N-vinylformamide. The lithium battery according to item 1 of the patent application scope, wherein the positive electrode material includes at least one of lithium cobaltate, ternary material, and lithium iron phosphate. The lithium battery according to item 1 of the patent application scope, wherein the negative electrode material includes at least one of graphite, lithium titanium oxide, and lithium metal.