Battery design based on nitrate oxidation reduction and application thereof

Abstract

The invention discloses a lithium nitrate battery, and belongs to the technical field of lithium ion batteries. In particular to a novel battery based on a nitrate ion oxidation-reduction mechanism, the battery does not need a positive active material, and lithium nitrate can be used for ion conduction and can also play a role in storing electrons; the capacity of the battery far exceeds that of an existing commercial lithium battery, and a brand new energy storage technology is expected to be provided for the market.

Description

Technical Field

[0001] The present invention relates to the technical field of battery energy storage, and in particular to the design, preparation and application of a lithium-lithium nitrate battery. Background Art

[0002] Electrochemical energy storage systems have become one of the hot spots of major scientific and technological development plans of various countries due to their advantages such as safety, stability, environmental friendliness and wide application range. In the current energy storage system, lithium-ion batteries have long been the most widely used energy storage system due to their long cycle life, and their theoretical energy density is expected to exceed 500wh / kg at this stage. Lithium-ion batteries are also called rocking chair batteries. Lithium ions are repeatedly embedded and inserted between the positive and negative electrodes in the battery system. The negative electrode mainly includes embedded graphite, alloy silicon electrode and metallic lithium; metallic lithium (Li) has a very high theoretical capacity (3,860mAh g -1 ), the lowest electrochemical redox potential (-3.04 V vs. SHE) and low density (0.534 g cm -3 ), is considered to be the ultimate negative electrode material to replace graphite negative electrode in high-energy rechargeable batteries. In order to give full play to the advantages of lithium metal batteries, the selection of battery positive electrode materials is also particularly critical. So far, the main positive electrodes are lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, and nickel-rich layered oxides that have been used in lithium-ion batteries. Lithium metal anode (LMA) can also be paired with conversion positive electrodes such as elemental sulfur and gaseous oxygen to construct lithium sulfur (LiS) and lithium air (LiO 2 ) batteries. In addition to the low cost advantage of naturally abundant sulfur and air, these conversion cathodes have higher energy density than deintercalation transition metal compound cathodes. However, sulfur and its discharge products (Li 2 S or L i 2 S 2 ) is difficult to directly act on the positive electrode material due to its low conductivity and insulation, resulting in a decrease in the utilization rate of sulfur active substances. Secondly, elemental sulfur and discharge product Li 2 Due to the different volume density of S, the positive electrode volume expands seriously (~80%) during the cycle. In addition, the shuttle effect and self-discharge behavior of soluble polysulfides are serious, resulting in rapid decay of battery capacity, and the energy density of lithium-sulfur batteries is also limited by the sulfur positive electrode content. Lithium-air batteries are open systems, and current research is still at the stage of inputting pure O 2 In the research stage, if air is input, other components in the air will have currently unknown effects on the positive electrode material, especially the effect of water vapor.

[0003] In past studies, some electrode materials have discharged far more than their theoretical capacity. The main reasons for this phenomenon are the formation and decomposition of electrolyte derivatives, the interfacial electron storage of metals, and the redox reaction of lithium-containing substances. For example, after the discharge of cobalt carbonate, metallic cobalt and lithium carbonate will be generated, and the metallic cobalt will further decompose the lithium carbonate to form lithium carbide and lithium oxide. This lithium salt redox reaction will provide huge capacity. Therefore, if a breakthrough in traditional lithium-ion batteries is designed based on a new energy storage mechanism, a new type of lithium battery that is sealed and not limited by the quality of the positive electrode will bring a revolutionary breakthrough to electrochemical energy storage technology. Summary of the invention

[0004] The purpose of the present invention is to design a lithium-lithium nitrate battery based on the lithium nitrate redox principle in response to the intrinsic limitations of existing lithium batteries. The positive electrode of the battery has no active substance, only conductive carbon, etc. The lithium nitrate in the electrolyte plays an ion conduction role, and the nitrate ions therein act as active substances to store and release electrons. The battery far exceeds the capacity of existing commercial lithium batteries and is expected to provide the market with a new energy storage technology.

[0005] Specifically, the invention scheme of the present disclosure is as follows:

[0006] In the first aspect of the present disclosure, the embodiments of the present application provide a new lithium-lithium nitrate battery, characterized in that the negative electrode of the battery is metallic lithium, the electrolyte is a lithium nitrate solution, the positive electrode is coated with a conductive carbon current collector, and the diaphragm is glass fiber, and can be directly assembled into a button battery or a soft-pack battery for operation.

[0007] The lithium salt of the lithium nitrate solution is lithium nitrate, and the solvent is one or more of dimethyl sulfoxide, dimethyl ether, ethyl acetate, dimethylformamide, and dimethylacetamide;

[0008] The conductive carbon is one or more of single-walled carbon nanotubes, acetylene black, conductive graphite, and graphene;

[0009] The current collector is one of carbon paper, carbon cloth, aluminum mesh, and nickel foam;

[0010] The adhesive used in the coating is polyvinylidene fluoride dissolved in N-methylpyrrolidone.

[0011] Through a large number of experiments, the present invention has found that the battery assembled by metal lithium-lithium nitrate solution-conductive positive electrode has very excellent electrochemical performance. After testing, the battery of the present invention has excellent electrochemical performance at 100mA g -1 At a current density of 1.5 mAh cm, the maximum discharge capacity can reach 19 mAh cm -2 ; The discharge products are lithium nitrite and lithium oxide; when the capacity is set to 1 mAh cm -2With a limited capacity, the battery can be stably cycled for 100 cycles, and the median discharge voltage can be stabilized at around 1.5V.

[0012] In a preferred embodiment, in the lithium nitrate electrolyte, the molar concentration of lithium nitrate is 1 mol / L to 5 mol / L.

[0013] In a preferred embodiment, in the lithium nitrate electrolyte, the solvent used is dimethyl sulfoxide.

[0014] In a preferred embodiment, the positive electrode conductive carbon is single-walled carbon nanotubes.

[0015] In a preferred embodiment, the positive electrode current collector is carbon paper.

[0016] The present invention also provides an application example of the above-mentioned lithium nitrate battery. The negative electrode of the lithium nitrate battery is metal zinc, the electrolyte is a 3 mol / L lithium nitrate dimethyl sulfoxide solution, the positive electrode is a carbon paper current collector, and the lithium nitrate battery is suitable for large-scale energy storage power stations, such as wind energy, tidal energy and other clean energy grid peak regulation.

[0017] Advantages and beneficial effects of the present invention:

[0018] 1. The lithium nitrate battery provided by the present invention has an ultra-high capacity, which is dozens of times higher than that of conventional commercial lithium batteries.

[0019] 2. The lithium nitrate electrolyte used in the present invention has low cost, is easy to mix, has a wide range of raw material sources, and is suitable for industrial production.

[0020] 3. The lithium nitrate battery provided by the present invention is easy to assemble and can directly use a closed button battery. Compared with a high-capacity open lithium-air battery, the lithium nitrate battery has lower environmental requirements and has a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A schematic diagram of the charging and discharging mechanism of a lithium nitrate battery provided in Example 1 of the present application;

[0023] Figure 2 The voltage curve of the fully discharged lithium nitrate battery provided in Example 1 of the present application is adopted;

[0024] Figure 3The lithium nitrate battery provided in Example 1 of the present application is 1 mAh cm -2 Cycling performance and median voltage performance diagram under limited capacity;

[0025] Figure 4 The lithium nitrate battery provided in Example 1 of the present application is used to light up an LED lamp. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0027] Example 1

[0028] The lithium nitrate battery in this example has an electrolyte composed of lithium nitrate and dimethyl sulfoxide. The preparation method is as follows: lithium nitrate is weighed according to a volume molar concentration of 4 mol / L, and dissolved in a certain amount of dimethyl sulfoxide to obtain the electrolyte containing lithium nitrate in this example. The positive electrode uses carbon nanotubes and polyvinylidene fluoride dissolved in N-methylpyrrolidone. The two are mixed in a mass ratio of 4:1 and coated on the nickel foam, and the cut pieces are vacuum dried;

[0029] Lithium nitrate battery assembly: The negative electrode uses metallic lithium, the separator uses glass fiber, and the positive electrode is directly assembled into a button battery for electrochemical testing.

[0030] The reaction diagram is as follows Figure 1 As shown, discharging the positive electrode is accompanied by the reduction of nitrate to nitrite and the generation of lithium oxide, while charging is exactly the opposite.

[0031] Figure 2 This is the voltage curve of the fully discharged lithium nitrate battery, which proves that the lithium nitrate battery can show about 19 mAh cm when fully discharged. -2 capacity.

[0032] Figure 3 For lithium nitrate batteries at 1 mAh cm -2 Cycling performance and median voltage performance at limited capacity. It can be seen that 1 mAh cm can still be maintained after 100 cycles. -2 The capacity of the battery is increased, and the median discharge voltage remains basically unchanged.

[0033] Figure 4 The lithium nitrate battery was used to light up the LED light, and the results showed that the battery can easily light up the green LED light.

[0034] Example 2

[0035] This embodiment provides a lithium nitrate battery. The difference from the embodiment 1 is that the electrolyte solvent in the embodiment 1 is replaced with dimethyl ether, and the lithium salt concentration is changed to 1 mol / L.

[0036] The corresponding electrochemical performance test results are as follows: the limited capacity is 0.2 mAh cm -2 , and can stably cycle 100 times.

[0037] Example 3

[0038] This embodiment provides a lithium nitrate battery. The difference from the embodiment 1 is that the lithium salt concentration of the electrolyte in the embodiment 1 is replaced with 4 mol / L

[0039] The corresponding electrochemical performance tests were carried out and the results are as follows: the limited capacity is 0.5 mAh cm -2 , and can stably cycle 200 times.

[0040] Example 4

[0041] This embodiment provides a lithium nitrate battery. The difference from the embodiment 1 is that the positive electrode described in the embodiment 1 is replaced with carbon paper coated with carbon nanotubes.

[0042] The corresponding electrochemical performance test results are as follows: the limited capacity is 0.1 mAh cm -2 , and can stably cycle 100 times.

[0043] Example 5

[0044] This embodiment provides a lithium nitrate battery. The difference from the embodiment 1 is that the positive electrode described in the embodiment 1 is replaced with a carbon paper coated with graphene.

[0045] The corresponding electrochemical performance test results are as follows: the limited capacity is 0.2 mAh cm -2 , and can stably cycle 100 times.

[0046] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0047] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

[0048] In this specification, the same or similar parts between the various embodiments can be referred to each other. In particular, for the terminal embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method embodiment.

[0049] The above-described embodiments of the present application do not constitute a limitation on the protection scope of the present application.

Claims

1. A lithium nitrate battery, characterized in that: Lithium nitrate solution is used as the electrolyte. The negative electrode of the battery is metallic lithium, the electrolyte is lithium nitrate solution, the positive electrode is coated with a current collector of conductive carbon, and the diaphragm is glass fiber.

2. The lithium nitrate battery according to claim 1, characterized in that: The electrolyte solvent is one or more of dimethyl sulfoxide, dimethyl ether, ethyl acetate, dimethylformamide, and dimethylacetamide.

3. The lithium nitrate battery according to claim 1, characterized in that: The lithium salt concentration of the lithium nitrate electrolyte is 1 mol / L-5 mol / L.

4. The lithium nitrate battery according to claim 1, characterized in that: The conductive carbon is one or more of single-walled carbon nanotubes, acetylene black, conductive graphite, and graphene.

5. The lithium nitrate battery according to claim 1, characterized in that: The current collector is one of carbon paper, carbon cloth, aluminum mesh and nickel foam.

6. The lithium nitrate battery according to claim 1, characterized in that: The binder used for the positive electrode is polyvinylidene fluoride dissolved in N-methylpyrrolidone, which is mixed with conductive carbon in a mass ratio of 1:4-1:6 and finally coated on the current collector.

7. Application of the lithium nitrate battery as claimed in claim 1 or the method for preparing the electrolyte and positive electrode of a lithium nitrate battery as claimed in any one of claims 2 to 6 in the field of new energy industry.

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