High-capacity and long-life lithium-ion battery

Abstract

The invention is related to using MWCNT (Multi-Walled Carbon Nanotube) compound modified with benzimidazole-2-thione as an anode electrode in Li-ion batteries to enable rechargeable batteries as high capacity and long-life batteries.

Description

[0001] DESCRIPTION

[0002] High-capacity and long-life lithium-ion battery

[0003] Field of the Invention

[0004] The invention generally relates to lithium-ion (Li-ion) batteries for energy storage.

[0005] The invention particularly relates to the use of MWCNT (Multi-Walled Carbon Nanotube) compound modified with benzimidazole-2-thione as an anode electrode in Li-ion batteries, enabling the use of rechargeable batteries as high- capacity and long-life batteries.

[0006] State of the Art

[0007] Nowadays, Li-ion batteries have become very popular in energy storage systems and their use is rapidly spreading. Batteries are systems that store electrochemical energy and can convert it into electrical energy when desired. When their basic structures are examined, they are systems consisting of a cathode electrode, a separator membrane, an anode electrode, and an electrolyte. With the rapid spread of batteries in our daily lives, intensive studies are being carried out on the development of their structures.

[0008] When the batteries used in the current technique are considered, the most common cathode materials can be given as LiCoC , LiMn2O4, LiNi0.8Co0.15AI0.05O2, and LiFePO4. The most common anode materials used in batteries are carbon-based graphite, graphene, and graphene oxide. When the carbon-based anode materials are examined, their most basic features can be seen as being abundant in nature and easily forming bonds with Li-ions in the form of LiCe. Therefore, it is possible to develop new electrodes with carbon derivatives. Carbon nanotube is a popular anode material in recent years and is widely studied. However, when the existing studies are examined, it is determined that there is no anode study on MWCNT modified with benzimidazole-2-thione. When the studies on the subject in the known state of the art were considered, some documents were encountered. In the document numbered US11462740B2, it is mentioned that an imidazole-based paste was created for the design of an electrode for electrochemical devices, and the production of this electrode contains a conductive material, an imidazole compound, a binder, and an organic solvent. The organic compound used in this document is an imidazole derivative compound. This compound is an N-heterocyclic compound that is different from benzimidazole in terms of its core structure. In addition, since there is no benzene ring in the imidazole groups, many of its physical properties (such as solubility, electronic transitions, polarity, and charge) are different from benzimidazole groups. The imidazole compound used in this document is used in the cathode of the battery in molecular structure and contributes to the formation of molecular ions as a result of deprotonation.

[0009] Document number US2016118652A1 is related to the lithium-ion battery and anode material for this battery. Among the organic compounds used in this document, only organic compounds numbered 2 and 3 are imidazole derivative compounds. Other compounds are pyridine, pyrazine, pyrimidine, pyridazine, triazine, and phthalimide compounds. These compounds form a layer on the anode electrode surface with carbon-containing substrates. In addition, it is mentioned in this document that graphite, graphene, hard carbon, soft carbon, single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), carbon fiber, carbon alloy, carbon metal oxide, Si / C composite material, mesocarbon microbeads (MCMB), mesophase graphite, mesoporous graphite or a combination of these are used as anode active material.

[0010] As a result, developments are being made regarding Li-ion batteries, therefore new structures are needed that will eliminate the disadvantages mentioned above and provide solutions to existing systems. Aim of the Invention

[0011] The present invention relates to a lithium-ion battery that meets the above- mentioned requirements, eliminates all disadvantages, and provides some additional advantages.

[0012] The main purpose of the invention is to provide a high-capacity and long-lasting Li-ion battery.

[0013] One purpose of the invention is to provide technological and commercial production of rechargeable batteries in the range of 2 volts to 4.3 volts using the benzimidazole-2-thione modified MWCNT material, which can provide an average initial potential of 0-3 volts from the initial battery formation.

[0014] In order to realize all the advantages mentioned above and understood from the detailed explanation below, the present invention is a Li-ion battery that is used as an energy storage element and provides high capacity and long-lasting use with its rechargeable structure; A structure that includes the use of the benzimidazole-2-thione modified MWCNT material as an anode has been obtained.

[0015] The structural and characteristic features of the invention and all its advantages will be understood more clearly thanks to the figures given below and the detailed explanation written by making references to these figures. Therefore, the evaluation should be made by taking these figures and detailed explanations into consideration.

[0016] Figures Clarifying the Invention

[0017] To best understand the structure of the present invention and its advantages together with the additional elements, it should be evaluated together with the figures explained below.

[0018] Figure 1: FTIR spectra of benzimidazole-2-thione (a) structure, benzimidazole- 2-thione-modified MWCNT (b) and pure MWCNT (c) structure Figure 2: EDX spectra of MWCNT (a) structure and Benzimidazole-2-thione- modified MWCNT (b) structure

[0019] Figure 3: X-ray spectra of MWCNT structure and benzimidazole-2-thione- modified MWCNT structure

[0020] Figure 4: SEM images of the MWCNT structure at different magnifications

[0021] Figure 5: SEM images of the benzimidazole-2-thione-modified modified MWCNT structure at different magnifications

[0022] Figure 6: EDX elemental maps of the MWCNT (a) structure and the benzimidazole-2-thione-modified MWCNT (b) structure.

[0023] Figure 7a: The present invention is a view of a representative button battery produced by the application.

[0024] Figure 7b: The appearance of a representative button cell battery produced according to the application of the invention.

[0025] Figure 8: Cyclic voltammetry result for the half-cell of the developed anode

[0026] Figure 9: Capacitance measurement results up to 250 cycles between 0-3V at 100 mA / g current density

[0027] Figure 10: Performance measurements of the produced anode material in halfcell tests at different current densities

[0028] Elements Helping to Understand Figures

[0029] 1 . Positive pole

[0030] 2. Negative pole

[0031] 3. Cathode material

[0032] 4. Anode material

[0033] 5. Insulator separator Detailed Description of the Invention

[0034] In this detailed description, the preferred embodiments of the Li-ion battery, which is the subject of the invention, are explained only for a better understanding of the subject and in a way that does not create any limiting effect.

[0035] The Li-ion battery, which is the subject of the invention, is produced by using the benzimidazole-2-thione modified MWCNT material as an anode and designing it as a cathode / separator / anode. The production of the battery, which is the subject of the invention, consists of the following process steps in its most general form; production of benzimidazole-2-thione modified MWCNT powders; laying the anode powders on the current collector and turning them into cathode electrodes; cathode or separator membrane benzimidazole-2-thione modified MWCNT anode cell production.

[0036] The production of the said Li-ion battery is carried out in more detail with the steps stated below;

[0037] - Synthesis of benzimidazole-2-thione structure For the synthesis of (1- allyl-3-(2-methylbenzyl)benzimidazole-2-thione) compound; 1 -al ly l-3-(2- methylbenzyljbenzimidazolium chloride (2 mmol, 598 mg), sulfur (2.4 mmol, 77 mg) and potassium carbonate (2.4 mmol, 331 mg) are added to a Shleng. The mixture is dried by heating under vacuum and then stirred in 15 mL of 99% pure ethyl alcohol at 70-75 °C for 24 hours (Scheme 1). Then, ethyl alcohol is evaporated under a vacuum. Pure water is added to the remaining solid, heated to 60 °C, and cooled to room temperature. Dichloromethane is added to the aqueous mixture to extract the organic phase. The molecular level water in the extracted solution is dried with magnesium sulfate. The solution is passed through a 1 cm thick silica gel column. Dichloromethane is removed under vacuum. The final product is then crystallized from a dichloromethane / pentane (1 / 2) mixture. Yield: 81 % (476 mg).

[0038] Scheme 1. 1-allyl-3-(2-methylbenzyl)benzimidazole-2-thione

[0039] - The non-covalent modification method is preferred for the synthesis of benzimidazole-2-thione modified MWCNT structure. In this modification, first, the MWCNT structure is dispersed in THF. To provide a homogeneous distribution, the system is homogenized in an ultrasonic bath for approximately three hours. Then, 1 -allyl-3-(2- methylbenzyl)benzimidazole-2-thione compound is added to the system at a ratio of 1 :10. The system is stirred at room temperature for three hours and then refluxed for approximately eight hours. After the reflux process, the system is cooled to room temperature and stirred at 2500 rpm for three days. Afterwards, the solvent is removed from the rested system by vacuum. The obtained modified structure is washed with methanol several times and dried in a vacuum oven at 45-50 °C (Scheme 2). In this way, the production of benzimidazole-2-thione modified MWCNT powders is achieved. The analysis of the obtained structure was confirmed by FTIR (Figure 1 ), SEM_EDX (Figure 2 and Figure 4), and XRD (Figure 3) analyses. A comparison of the SEM images of the unmodified structure (Figure 5) and the SEM images of the benzimidazole-2-thione compound modified structure (Figure 6) clearly shows that the designed molecule was formed.

[0040]

[0041] Scheme 2. Synthesis of 1-allyl-3-(2-methylbenzyl)benzimidazole-2-thione Modified MWCNT Structure

[0042] - Powdered benzimidazole-2-thione modified MWCNT, PVDF (Polyvinylidene fluoride), and CB (Carbon Black) chemical powders are weighed at different ratios (for example, 80%:10%:10%) of the total mixture weight and mechanically mixed until a homogeneous mixture is obtained.

[0043] - NMP (N-methyl-2-pyrrolidone) liquid is then added to the homogeneous mixture consisting of the above-mentioned compounds, PVDF and CB, and the powdered material is turned into mud.

[0044] - The resulting mud is then laid on a copper foil to form a layer of approximately 200 pm thickness. After this process, the aluminum foil with the mud on it is dried in an oven at approximately 110 °C to evaporate the NMP liquid and produce electrode materials for single-use sodium batteries. - Benzimidazole-2-thione modified MWCNT anode materials are used in air or

[0045] Ar (Argon) gas-filled oxygen-free environment as a suitable medium for the storage of electrolytes and electrodes used, and a rechargeable Li-ion battery is formed as follows; battery bottom cover, electrode as cathode, electrolyte liquid, membrane, electrolyte liquid, cathode, metal conductor, spring and battery top cover.

[0046] Benzimidazole-2-thione modified MWCNT (multi-walled carbon nanotube) material can be produced in a structure that can be converted into single crystal, thin film (coatings obtained using systems such as e-beam, electrocoating, atomic layer coating, sputter, thermal evaporator, less than 1 pm thick), thick film (coatings produced by methods such as immersion, sol-gel, spraying, more than 1 m thick) or polycrystalline (powders produced by solid- state synthesis, hydrothermal methods, glass ceramic methods) materials without deteriorating their structural properties.

[0047] Figure 7a and Figure 7b show representative views of button cells and alkaline cells produced by the above method. The mentioned batteries are generally composed of; a positive pole (1 ) and negative pole (2) forming the outer parts of the battery; cathode material (3) and anode material (4); and it consists of an insulating separator (5) that prevents short circuits by positioning it between the cathode material (3) and the anode material (4).

[0048] The cyclic voltammetry results of the half-cells produced in button cells are given in Figure 8 and the obtained graph successfully shows that they exhibit anodic properties. In the galvanostatic measurements made up to 250 cycles at a current density of 100 mA / g given in Figure 9, it is seen that the initial capacity value is 1524 mAg / g and then shows a stable cycle performance. In addition, the current density capacity measurements of the half-cells produced were taken and presented in Figure 10, and while the capacity value was 1200 mAh / g at low current densities, it was 480 mAh / g at high currents. This clearly shows that the produced anode material has strong battery properties.

[0049] The surface properties of MWCNT are strengthened using the electron-rich olefin structure. Benzimidazole-2-thione structure rich in IT electrons to be used in structural modification is synthesized. Starting from the benzimidazole-2- thione structure in the syntheses, a benzimidazole-2-thione derivative structure is obtained. To strengthen the adhesion to the N-functional structure of the MWCNT surface, phenylene and vinylene functional benzimidazole-2-thione compound is synthesized. The structural analysis of the synthesized compound is confirmed by FTIR, elemental analysis, and NMR analyses. In the next step, MWCNT modification is carried out using non-covalent interactions. The basic properties of the structure obtained in this process are confirmed by FTIR, XRD, and SEM-EDX analyses. Especially the organic groups bonded to the surface are seen on the MWCNT surface in FTIR analysis. In addition, the increase in surface cavities in EDX analysis is determined by the presence of N and S peaks. Again, the dimensional increase in the MWCNT structure after modification also confirms the presence of organic groups on the surface. Later, the relevant structure was used in battery production, and its basic values were checked.

Claims

CLAIMS1 . It is a Li-ion battery used as an energy storage element and provides high capacity and long-lasting use with its rechargeable structure, and its feature includes the use of benzimidazole-2-thione modified MWCNT material as the anode.

2. It is a Li-ion battery according to claim 1 , and its feature is that the benzimidazole-2-thione modified MWCNT material is in the form of a single crystal or thin film or thick film or polycrystalline material.

3. It is a Li-ion battery production method used as an energy storage element and provides high capacity and long-lasting use with its rechargeable structure, its features are;• production of benzimidazole-2-thione modified MWCNT powders,• laying anode powders on the current collector and turning them into cathode electrodes, and• cathode or separator membrane benzimidazole-2-thione modified MWCNT anode cell production process steps.

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