Battery comprising 2d carbon quantum dot materials in electrodes and electrolyte solution, and manufacturing method thereof

Abstract

A battery comprising 2D carbon quantum dot (2D-QDs) materials in the electrodes and in the electrolyte solution, consisting of a positive electrode, a negative electrode, a separator, and an electrolyte solution, wherein the electrodes are coated with a mixture comprising an active material containing 2D carbon quantum dots, a conductive material, and a binder, and wherein the electrolyte solution comprises 2D carbon quantum dot materials, and wherein the positive electrode, the negative electrode, the separator, and the electrolyte solution are assembled into the battery housing using a compression assembly device to obtain a battery comprising 2D carbon quantum dot materials.

Description

[0001] Description

[0002] Title of the Invention

[0003] Battery comprising 2D carbon quantum dot materials in electrodes and electrolyte solution, and manufacturing method thereof.

[0004] Technical Field of the Invention

[0005] Electrical engineering, electrochemical engineering, and electrical physical sciences related to batteries incorporating 2D carbon quantum dot materials in the electrodes and electrolyte solution, as well as the method for producing the same.

[0006] Background of the Invention

[0007] Batteries are widely used devices for storing electrical energy and are commonly found in applications such as automobiles, mobile phones, iPads, notebook computers, flashlights, and more. Among the most commonly used types are lithium-ion batteries and lead-acid batteries. However, both types have their respective advantages and disadvantages. The main advantage is the ability to store energy for later use. On the downside, internal components of batteries can be hazardous, especially as they degrade and require special disposal. Lithium-ion batteries, in particular, can react with air, potentially leading to rapid combustion. Additionally, lithium-ion batteries are relatively expensive.

[0008] Currently, lithium-ion batteries are widely used rechargeable batteries, commonly found in household electrical appliances, wireless electronic devices, and portable gadgets. However, as Thailand does not have domestic lithium resources and the cost of lithium importation is relatively high, this presents a limitation and may potentially lead to future challenges. Additionally, the invention and development of electrical energy storage devices is an area that deserves considerable attention and advancement, especially due to the current high demand for electricity. Furthermore, environmental protection is another essential concern that must be addressed in parallel with technological development.

[0009] Two-dimensional carbon quantum dot materials (2D-QDs), such as reduced graphene oxide quantum dots (rGO-QDs), are nanoscale two-dimensional materials with sizes smaller than 10 nanometers, and are thus classified as quantum dots. The rGO-QDs are derived from a process that reduces the oxygen content in graphene oxide (GO), which is a chemically modified material enriched with oxygen-containing functional groups. The development ofrGO-QDs represents a significant advancement in nanotechnology, combining the superior properties of graphene with the tunability of quantum dot particles. The importance of rGO-QDs lies in their unique characteristics such as high electrical conductivity, light absorption and emission capability, and versatile chemical reactivity. Additionally, due to their high surface area and conductivity, graphene oxide quantum dots are well-suited for energy storage devices such as batteries, as they can enhance charge storage capacity, enable faster chargedischarge rates, and extend cycle life.

[0010] The electrodes of a battery are divided into the positive electrode or cathode and the negative electrode or anode. The efficiency of a battery can be improved by enhancing the ability of both the cathode and anode to store electric charge as much as possible, based on the principle of electrochemical reactions — namely oxidation and reduction reactions, collectively referred to as redox reactions — and the physical principle of electrostatic charge storage between the surfaces of the materials forming the electrodes. The materials that play this role are called active materials. In addition, the electrode composition includes conductive materials that facilitate the flow of electrical charge — specifically electrons — toward the current collector. These are referred to as conductive materials. There is also a binder material, which serves to bind the electrode materials to the current collector. As for the electrolyte solution, it serves as the medium through which ions can move between the positive and negative electrodes. Ions can only travel within the electrolyte solution, which must also prevent the movement of electrons. The ions in the electrolyte dissociate and are absorbed on the surface of the electrodes. The separator sheet between the electrodes prevents the electrodes from coming into direct contact, which could otherwise result in a short circuit between the positive and negative terminals, and also prevents electrostatic discharge.

[0011] According to a search on international patent databases related to inventions involving batteries, the following were found:

[0012] Patent No. US9496090B2 discloses the use of graphene material blended into the electrolyte and electrodes of a supercapacitor. This aims to enhance the dielectric constant and increase the charge storage capacity in order to improve the energy storage efficiency of the supercapacitor.Patent Application No. WO2014 / 072877A3 discloses the use of nano graphene platelets blended into an ink formulation for printable and coatable electrodes, which can be fabricated into supercapacitors.

[0013] Patent Application No. W02016 / 070020A2 discloses the invention of an electrode for a supercapacitor comprising a charge- supporting component that includes graphenic carbon and a binder. The charge-supporting component consists of activated carbon, while the graphenic carbon material is prepared through a heat treatment process.

[0014] Patent Application No. US 2014 / 0104752 Al discloses the invention of an electric double-layer ultracapacitor electrode, which includes a current collector, a positive and a negative electrode, and an electrolyte that acts as an ion-conducting medium in contact between the electrodes and the separator. The electrolyte comprises acetonitrile and ammonium salts.

[0015] Patent Application No. US 2013 / 0323607 Al discloses the invention of secondary electrochemical cells in which the anode and cathode include components comprising an electrochemical cell cathode material, an electrode separator, and an electrolyte. The electrolyte component comprises at least a salt solution and an organic solution, while the electrode separator and electrolyte combination provide a specific surface electrical resistance of less than 2 ohm-centimeters (ohm-cm2).

[0016] According to a search of patents and petty patents within Thailand patent database related to inventions involving batteries, the following information was found:

[0017] Petty Patent Application No. 1803002144, titled "Binder-Free Cathode Material for Lithium- Sulfur Batteries and Preparation Method Thereof," discloses a binder-free cathode material for lithium- sulfur (Li-S) batteries, comprising a layer of reduced graphene oxide, a composite material layer containing sulfur, nitrogen-doped reduced graphene oxide, and carbon nanotubes coated on the reduced graphene oxide layer, and a protective coating layer over the composite material. The protective layer is made from a material selected from the group consisting of graphene oxide, titanium dioxide, manganese oxide, and mixtures thereof.

[0018] Petty Patent Application No. 1903003329, titled "A Method for Producing a Cathode Electrode for Lithium- Sulfur Batteries Comprising Sulfur Material Encapsulated with Carbon Nanospheres and Carboxyl-Functionalized Carbon Nanospheres," discloses a process involving high-energy mechanical milling and colloidal mixing to obtain a double- shelledcore-shell structured sulfur material. The core and double-shell (sphere) configuration helps to reduce the polysulfide shuttle mechanism, thereby improving the Coulombic efficiency and stability of lithium-sulfur batteries.

[0019] Patent Application No. 2001001689, titled "Lithium Doping Process for Anode Materials in Lithium-Ion Batteries via Hydrogen-Releasing Chemical Reaction," discloses the preparation of anode materials using a prelithiation process, in which a desired amount of lithium is introduced to react with the anode material. The lithium intercalates into the structure of the anode material to reduce the particle size of the reactive anode material to 10-20 nanometers. The resulting nanoparticles from the lithium doping process are then mixed with conductive materials, binders, or coupling agents in the preparation of the electrode.

[0020] It can be seen that the existing prior inventions have claimed rights in the areas of binder-free cathode materials for lithium-sulfur batteries, processes for producing cathode electrodes for lithium- sulfur batteries, as well as lithium doping processes for anode materials in lithium-ion batteries using hydrogen-releasing chemical reactions.

[0021] Summary of the Invention

[0022] The invention relates to a battery incorporating two-dimensional carbon quantum dot materials (two-dimensional quantum dots) in both the electrodes and the electrolyte solution. The battery comprises a positive electrode, a negative electrode, a separator, and an electrolyte solution. The electrodes are coated with a composite mixture containing an active material that includes two-dimensional carbon quantum dots, a conductive material, and a binder. The electrolyte solution also contains two-dimensional carbon quantum dot materials. The positive electrode, negative electrode, separator, and electrolyte solution are then assembled onto the battery base using a pressing assembly machine, resulting in a battery containing two-dimensional carbon quantum dot materials.

[0023] The objective of this invention is to develop an alternative approach to identifying materials that can be used to reduce lithium consumption to the minimum while being environmentally friendly for use in energy storage batteries. The inventors have designed and developed a battery that incorporates two-dimensional carbon quantum dot materials in both the electrodes and the electrolyte, providing a potential alternative energy source in the future. This type of battery is low-cost, non-flammable upon exposure to air, easy to manufacture with a simple, non-complex process, lightweight, low in production cost, and capable of efficientenergy storage. It thus represents a promising alternative with positive implications for both the economy and the environment.

[0024] Brief Description of the Drawings

[0025] Figure 1 illustrates an X-ray diffraction (XRD) pattern of the electrode material in the battery containing two-dimensional carbon quantum dot materials in the electrodes and the electrolyte.

[0026] Figure 2 illustrates a UV- Visible (UV-Vis) absorption spectrum of the electrolyte solution in the battery containing two-dimensional carbon quantum dot materials in the electrodes and the electrolyte.

[0027] Figure 3 illustrates a graph showing the voltage, capacity, current, and electrical energy during the charge and discharge process of the battery containing two-dimensional carbon quantum dot materials in the electrodes and the electrolyte, using a charge current of 0.5 A within a voltage window between 0.5 and 2 V.

[0028] Detailed Description of the Drawings

[0029] A battery comprising 2D carbon quantum dot materials in electrodes and electrolyte solution contains a positive electrode (cathode), a negative electrode (anode), a separator, and an electrolyte solution.

[0030] Wherein the composite mixture used for coating the positive electrode (cathode) comprises

[0031] active material 70-85% by weight

[0032] a conductive material 5-20% by weight

[0033] binder 5-15% by weight

[0034] wherein the active material comprising

[0035] an oxide material 98-99.999% by weight two-dimensional carbon quantum dot material: 0.001-2.0% by weight. Wherein the oxide material is selected from manganese oxide or vanadium oxide. Wherein the two-dimensional carbon quantum dot material is selected from reduced graphene oxide quantum dots or carbon quantum dots.Wherein the conductive material is selected from carbon black, acetylene black, graphene, reduced graphene oxide, graphite, or nano graphite.

[0036] Wherein the binder is selected from polyvinylidene fluoride (PVDF) or styrenebutadiene rubber (SBR).

[0037] Wherein the separator is a hydrophilic paper separator, which is an ion-permeable material that acts as an electrical insulator capable of preventing short circuits between the positive and negative electrodes.

[0038] Wherein the electrolyte solution comprises:

[0039] 2D carbon quantum dot material 0.001-2.0% by weight zinc compound 98-99.999% by weight The volume is adjusted to 100% with a solvent suitable for preparing the electrolyte solution.

[0040] Wherein the zinc compound is selected from zinc trifluoromethane sulfonate (Zn(OTf)2), zinc sulfate (ZnSCb), or zinc (II) bis(trifluoromethanesulfonyl)imide (Zn(TFSI)2).

[0041] Wherein the solvent for preparing the electrolyte solution is selected from deionized water or acetonitrile.

[0042] Wherein the positive and negative electrode materials is selected from thin electrically conductive metal sheets, including stainless steel sheets, copper sheets, titanium sheets, carbon sheets, aluminum sheets, or zinc sheets.

[0043] The method for producing a battery containing two-dimensional carbon quantum dot materials in the electrodes and the electrolyte comprises the following steps:

[0044] a. Prepare an electrolyte solution by mixing two-dimensional carbon quantum dot materials and a zinc compound in a solvent suitable for preparing the electrolyte solution. The mixture is stirred using an ultrasonic sonicator to obtain an electrolyte solution containing two-dimensional carbon quantum dot materials.

[0045] b. Prepare an electrode by mixing two-dimensional carbon quantum dot materials, a binder, and an oxide material in a solvent suitable for electrode preparation. The mixture is blended using an ultrasonic sonicator at a frequency range of 18-40 Hz for 3 - 5 hours until the mixture becomes homogeneous and forms a viscous paste.The solvent for electrode preparation is selected from N-methyl-2 -pyrrolidone (NMP) or dimethylformamide (DMF). The ratio of solid materials (two- dimensional carbon quantum dot materials, binder, and oxide material) to the solvent is in the range of 1 part solid to 2-3 parts solvent by weight.

[0046] Then, the resulting mixture is coated onto both sides of a thin electrically conductive metal sheet. The coated metal sheet is then dried in an oven at a temperature of 80°C for 24 hours to obtain electrodes containing two-dimensional carbon quantum dot materials.

[0047] c. Place the positive electrode obtained from step b inside the base of the battery, then place the separator on top of the said positive electrode, and place the negative electrode obtained from step b on top of the said separator, then add the electrolyte solution from step a, and seal with another piece of the battery base, then place the entire assembly into the pressing machine to obtain a battery containing two- dimensional carbon quantum dot materials in the electrodes and in the electrolyte.

[0048] Wherein the positive electrode, negative electrode, and separator are in the form of circular discs with a diameter of 10-20 millimeters for assembly into a coin cell battery,

[0049] or are in the form of rectangular sheets with a width of 1-5 centimeters and a length of 50-200 centimeters for assembly into cylindrical batteries of size 18650 or 28650,

[0050] or are in the form of rectangular sheets with a width of 5-30 centimeters and a length of 20-120 centimeters for assembly into pouch cell batteries.

[0051] Example of Coin Cell Battery Assembly:

[0052] Place the circular positive electrode sheet on the inner side of the back plate of the coin cell assembly unit, then place the circular separator sheet on top, followed by placing the circular negative electrode sheet, then add the electrolyte solution, followed by placing the front plate of the coin cell assembly unit, and place the entire assembly into the coin cell assembly machine to apply compression and assemble into a coin cell.Example of Cylindrical Cell Battery Assembly:

[0053] Place the positive electrode sheet as the first layer, followed by the separator sheet, and then the negative electrode sheet. Roll the layered sheets into a cylindrical form, then insert them into a cylindrical housing with dimensions of 18650 or 28650. After that, weld the electrical conductor to the negative electrode, then assemble and weld the electrical conductor to the positive electrode, then add the electrolyte solution. Afterward, place the entire assembly into the cylindrical cell assembly machine of size 18650 or 28650.

[0054] Example of Pouch Cell Battery Assembly:

[0055] Place the negative electrode sheet as the first layer, then place the separator sheet as the next layer, followed by the positive electrode sheet. This layer arrangement can be repeated as needed depending on the desired number of layers. After that, assemble and connect all the negative electrodes together, and assemble and connect all the positive electrodes together. Then, wrap the assembly with an alumina laminate film pouch. After that, fill in the electrolyte solution and place the entire assembly into the pouch cell assembly machine equipped with a vacuum suction system.

[0056] Best Mode of the Invention

[0057] As described previously in the detailed description of the invention.

Claims

Claims1 . A battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution, comprising a positive electrode (cathode), a negative electrode (anode), a separator, and an electrolyte solution,wherein the mixture for coating the positive electrode comprisingan active material 70-85% by weight,a conductive material 5-20% by weight, anda binder in an amount of 5-15% by weight,wherein the active material comprisingan oxide 98-99.999% by weight, and2D carbon quantum dots 0.001-2.0% by weight,wherein the separator is a hydrophilic paper separator that allows ion permeability and acts as an electrical insulator to prevent short-circuiting between the positive and negative electrodes, andwherein the electrolyte solution comprising- 2D dots in an amount of 0.001-2.0% by weight, and- zinc compounds in an amount of 98-99.999% by weight,with the total volume adjusted to 100% using a solvent for preparing the electrolyte solution.2 . The battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to claim 1 , wherein the solvent for preparing the electrolyte solution is selected from deionized water or acetonitrile.3 . The battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to claim 1 or 2 , wherein the oxide material is selected from manganese oxide or vanadium oxide.4 . The battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to any of claims 1 to 3 , wherein the 2D carbon quantum dot materials are selected from reduced graphene oxide quantum dots or carbon quantum dots.5 . The battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to any of claims 1 to 4, wherein the conductive material is selected from carbon black, acetylene black, graphene, reduced graphene oxide, graphite, or nano graphite.6 . The battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to any of claims 1 to 5 , wherein the binder is selected from polyvinylidene fluoride or styrene-butadiene rubber.7 . The battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to any of claims 1 to 6 , wherein the zinc compound is selected from zinc trifluoromethane sulfonate (Zn(OTf)2 ) , zinc sulfate (ZnSCb ) , or zinc (II) bis(trifluoromethanesulfonyl)imide (Zn(TFSI)2).8 . The battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to any of claims 1 to 7, wherein the materials used for the positive electrode and the negative electrode are selected from electrically conductive thin metal sheets comprising stainless steel sheets, copper sheets, titanium sheets, carbon sheets, aluminium sheets, or zinc sheets.

9. A method for producing a battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to any of claims 1 to 8 , comprising the following steps:( a) preparing the electrolyte solution by mixing the 2D carbon quantum dot materials and the zinc compound in a solvent for electrolyte preparation using an ultrasonic sonicator, resulting in an electrolyte solution comprising the 2D carbon quantum dot materials;(b) preparing the positive electrode by mixing the 2D carbon quantum dot materials, binder, and oxide material in a solvent for electrode preparation using a grinding device in an ultrasonic sonicator at a frequency range of 18-40 Hz for 3-5 hours until the mixture is homogeneous and viscous, wherein the solvent for electrode preparation is selected from N-methyl-2 - pyrrolidone (NMP) or dimethylformamide (DMF), and the ratio between solid materials (two-dimensional carbon quantum dot materials, binder, and oxide material) and the solvent is in the range of 1 part solid to 2-3 parts solvent by weight,then coating the obtained mixture on both sides of a conductive thin metal sheet and baking the coated sheet at 80 °C for 24 hours to obtain an electrode comprising the 2D carbon quantum dot materials;(c) placing the positive electrode obtained from step (b) inside the battery case, placing the separator on top of the positive electrode, then placing the negative electrode obtained from step (b) on the separator, filling the electrolyte solution obtained from step (a), sealing with another piece of battery case, and assembling with a pressing machine to obtain the battery comprising the 2D carbon quantum dot materials in the electrodes and in the electrolyte solution.

10. The method for producing a battery comprising 2D carbon quantum dot materials in the electrodes and in the electrolyte solution according to any of claims 1 to 9, whereinthe positive electrode, the negative electrode, and the separator are in the form of circular sheets having a diameter of 10-20 millimeters for assembly into a coin cell battery, or are in the form of rectangular sheets having a width of 1-5 centimeters and a length of 50-200 centimeters for assembly into a cylindrical battery of size 18650 or 28650, or are in the form of rectangular sheets having a width of 5-30 centimeters and a length of 20-120 centimeters for assembly into a pouch cell battery.

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