A supercapacitor production method derived entirely from waste fabric

Abstract

The invention relates to a supercapacitor production method in which all components (current collector, electrode material, separator and electrolyte) of supercapacitors used in energy storage are prepared using waste fabrics.

Description

[0001] A SUPERCAPACITOR PRODUCTION METHOD DERIVED ENTIRELY FROM WASTE FABRIC

[0002] Technical Field

[0003] The invention relates to a supercapacitor production method in which all components (current collector, electrode material, separator and electrolyte) of supercapacitors used in energy storage are prepared using waste fabrics.

[0004] State of the Art

[0005] Prior art supercapacitors consist of four main units in their structure; electrode material where the energy storage work takes place, current collectors that ensure that these electrode materials stand regularly and transfer the electric current from the network to the electrode material, separator that prevents the current collector / electrode material structure (electrode) from contacting each other and electrolyte material that can ionize when a certain voltage magnitude is applied. The electrolyte ions formed after the application of electrical potential should be able to pass easily through the separator.

[0006] Cellulosic materials are the most preferred type of separator. In recent years, polymeric and ceramic based separators have also been studied. There are also rare studies where natural materials are tested in the separator group. The main task of the separator is to prevent the electrodes from contacting each other. Another important feature expected from separators is that they should not prevent ion passage. For this reason, porous materials are preferred. Current collectors are generally prepared from metals or alloys with high electrical conductivity. If the resistance to electrical current is high, the internal resistance inside the supercapacitor cell increases and negatively affects the energy storage performance. Therefore, high conductivity is the most important feature sought in current collectors. In addition to metals or alloys, carbon papers with high electrical conductivity are also preferred as current collectors.

[0007] Electrolytes are an important component that determines supercapacitor performance. Electrolyte ions collect on the surface of the electrode material and allow energy storage. The higher the surface area of the electrode material, the higher the energy storage potential. The accessibility of the surface area by electrolyte ions is an important factor determining the performance. The high operating voltage range of the electrolyte material increases the energy and power density of the supercapacitor cell. There are many studies in the literature using different types of electrolytes. Electrolytes are divided into three main groups as liquid electrolytes, solid state / semi-solid state electrolytes and redox active electrolytes. Electrodes, which are the surfaces where energy is stored in supercapacitors, can be prepared from different materials.

[0008] These materials can be metal oxides (ruthenium oxide, manganese oxide, copper oxide, etc.), conductive polymers (polyaniline, polypyrrole, etc.) and various carbon-based materials (activated carbon, graphene, carbon nanotubes, etc.). Energy storage can take two forms. Energy can be stored electrostatically by the electric double layer formed on the electrode surface or electrochemically by redox reactions of metal oxides or heteroatoms at certain potential ranges. Depending on the type of energy storage, supercapacitors are called electric double layer capacitors or pseudocapacitors.

[0009] One of the most important problems observed in supercapacitors is the reduction in energy storage performance due to internal resistance. The contact resistance between the current collector made of different materials, the electrode material and the separator is one of the important factors affecting the performance. In order to attach the electrode material to the surface of the current collector, a binder (adhesive) is often used in the preparation stage. Since the binder is an insulator, it shows resistance to electric current.

[0010] This situation leads to increased intracellular resistance and decreased performance. In the literature, there are various studies on the preparation of supercapacitor cells without the use of binders in order to eliminate the negative effect of the binder. In some of these methods, carbon materials such as graphene, carbon nanotubes and carbon black are constructed in the form of small block structures by methods such as electro-spray storage, wet drawing, hydrothermal compounding. Although these processes eliminate the use of binders, they increase the production cost. On the other hand, binder-free supercapacitor cells with low production cost are also prepared by using carbonized structures such as carbon fiber, carbon fabric, carbon paper. Cells prepared in this way cannot reach the conductivity values provided by materials such as graphene, carbon nanotubes, carbon black, and also; since they do not have high surface area, they cannot exhibit the advantages of surface area due to the nature of electrode materials.

[0011] The biggest advantage of cells prepared without the use of binders is the flexibility of supercapacitors. Giving flexibility to supercapacitors is one of the most studied topics in energy storage applications today. Whether a binder is used or not, flexible or not, supercapacitor units constitute the biggest cost due to the materials they contain and their preparation. Metal-containing materials used as electrode materials (ruthenium, manganese, molybdenum, gold, etc.) and carbon-containing materials such as graphene, carbon nanotubes and carbon aerogels have high production costs. The increase in the unit cost of supercapacitors is another important factor limiting their use.

[0012] In the state of the art document titled "Supercapacitor performance of heteroatom doped activated carbon produced from waste fabric", the supercapacitor performance of heteroatom doped activated carbon produced from waste fabric is explained. In the document, studies on the effect of textile wastes on the performance of supercapacitors are discussed. In the document, only the creation of the electrode material from textile waste is mentioned.

[0013] In the patent document CN110136982, which is in the known state of the art, flexible electrode materials and methods of preparation and application of these materials are mentioned. In particular, a composite fabric electrode for a flexible supercapacitor and its preparation and application are described.

[0014] In the patent document CN108538643 in the known state of the art, a method of preparing a supercapacitor electrode from a flexible knitted fabric is mentioned. When the existing studies in the art were examined, there was a need to realize a supercapacitor production method in which all components of supercapacitors are prepared using waste fabrics.

[0015] Objectives of the Invention

[0016] The object of the present invention is to provide a supercapacitor production method in which all components of the supercapacitors (current collector, electrode material, separator and electrolyte) are prepared using waste fabrics.

[0017] Another object of the present invention is to provide a supercapacitor production method without the need for heteroatom modification processes, which enables the electrochemical performance to be increased thanks to the natural heteroatom content of the waste fabrics due to their dyeing.

[0018] Detailed Description of the Invention

[0019] The invention relates to a supercapacitor production method in which all components of supercapacitors used in energy storage are prepared using waste fabrics, comprising the steps

[0020] - Collection of waste fabrics,

[0021] - Carbonization of waste fabrics in a heat treatment furnace at different temperatures ranging from 200 - 700 °C in N2 gas atmosphere to obtain current collector and separator

[0022] - Mixing of carbonized waste fabrics with chemicals such as phosphoric acid (H3PO4), potassium hydroxide (KOH), potassium carbonate (K2CO3), sodium hydroxide (NaOH) or sodium carbonate (Na2CO3), zinc chloride (ZnCh) at ratios of 1 : 1, 1 : 1.5, 1 :2, 1 :2.5, 1 :3, 1:3.5, 1 :4, 1 :4.5 and 1 :5 by mass,

[0023] - Activation of the waste fabric - activation chemical mixture in a heat treatment furnace at different temperatures such as 450 °C, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C, 800 °C, 850 °C and 900 °C for different times such as 1, 1.5 and 2 hours under N2 gas atmosphere,

[0024] - Activated carbon samples obtained after activation were washed with distilled water to neutral pH and dried at 105 °C,

[0025] - The dried samples were first washed with 1 M hydrochloric acid (HC1) and 1 M hydrogen fluoride (HF), respectively,

[0026] - Preparation of the electrode material by washing again with distilled water to neutral pH and drying at 105 °C,

[0027] - Cutting the waste fabric samples into small pieces and drying at 105 °C to remove moisture,

[0028] Mixing dried waste fabric pieces with a solution of protic ionic liquid containing 80 wt% triethylammonium hydrogen sulfate and 20 wt% water, Pretreatment of the mixtures by heating in a stainless steel high pressure reactor at 125 °C, 150 °C, 175 °C, 200 °C and 225 °C for 2, 4, 8, 12, 16 and 24 hours,

[0029] After heating, ethanol is added to the mixture, filtered, washed with distilled water until a neutral pH value is obtained and dried in vacuum at 80 °C to obtain cellulose,

[0030] - The cellulose produced was transferred to 100 ml NaOH (6 wt%) - urea (4 wt%) aqueous solution and the solution was stirred at room temperature for 10 minutes and then kept at -20 °C for 24 hours,

[0031] - After 24 hours, stirring the solution at room temperature until homogeneous and transparent, adding 5 wt% H2SO4 to the solution and coagulating the cellulose hydrogel and removing it from other media components, Preparation of the electrolyte by washing the produced hydrogel with deionized water and removing impurities,

[0032] - Mixing activated carbon samples with carbon black in ethanol,

[0033] Spraying the prepared mixture with the help of a spray gun on a 1 cm x 1 cm, 2 cm x 2 cm, 2 cm x 4 cm, 4 cm x 4 cm, 4 cm x 12 cm sized current collector prepared from waste fabric, - Preparation of supercapacitor cell electrodes by drying the current collectors sprayed with activated carbon-carbon black mixture in a vacuum oven, Spreading the electrolyte on the prepared electrode surfaces,

[0034] - Placing the separator made of waste fabric between two prepared electrodes,

[0035] - Placing the structure containing the two electrodes, electrolyte and separator in an antistatic bag,

[0036] - Discharging the air in the bag

[0037] - Closing the bag with a bag sealing machine to complete the packaging process,

[0038] In another embodiment of the inventive method, a supercapacitor cell can also be prepared by using a binder during the preparation of the supercapacitor cell. In this case, activated carbon samples are mixed with binders such as polyvinyl difluoride (PVDF), carboxymethyl cellulose (CMC), polytetrafluoroethylene (PTFE) in the presence of carbon black.

[0039] The activated carbon-binder-carbon black ratio by mass is adjusted at different values as 80-20-0, 80-15-5, 80-10-10, 80-5-15, 80-0-20, 85-15-0, 85-10-5, 85-5-10, 85-0-15, 90-10-0, 90-5-5, 90-0-10. PVDF is dissolved in n-methyl pyrrolidone, CMC and PTFE are dissolved in water. The prepared mixture is sprayed into the current collector prepared from waste fabric with the help of a spray gun. The current collectors sprayed with activated carbon-binder-carbon black mixture are dried in a vacuum oven and the supercapacitor cell is prepared.

[0040] The method of the invention enables the low-cost production of all the units constituting the supercapacitor with the performance of commercial supercapacitors in the present art. The invention enables the recovery of a waste material that has limited use in the world. With the recovery of waste, carbon, water and chemical footprint is reduced and environmentally sensitive and high value- added products are obtained.

[0041] With the invention, flexible supercapacitors can be prepared without the need for binders. The invention enables the use of high surface area electrode material, which is not seen in flexible supercapacitors without binder in the present art. The invention also has the advantage of spontaneous production of heteroatomcontaining electrode material without any modification process due to various heteroatoms such as nitrogen and sulfur in fabric dyes.

[0042] The invention enables the use of a waste material as a separator. The invention also includes the conversion of the same waste into electrolyte material and its use in a supercapacitor cell.

[0043] Within the scope of the inventive method, current collector, electrode material, separator and electrolyte were produced using waste fabrics with different contents. Different processes were carried out for the preparation of supercapacitor units. With the carbonization process, various surface functional groups that cause a decrease in electrical conductivity on the fabric surface were removed from the structure and current collector and separator were produced.

[0044] Since the product obtained after carbonization is flexible, flexible supercapacitor production was carried out easily. For the production of electrode material, carbonization and activation processes of waste textile products in the presence of chemicals such as H3PO4, KOH, K2CO3, NaOH, Na2CO3, ZnCh were applied. For the synthesis of electrolyte from waste, cellulose and hemicellulose were firstly extracted from waste fabrics and then hydrogel production was carried out from cellulose and hemicellulose. Thus, all four units of a supercapacitor cell were produced from waste fabrics.

Claims

CLAIMS1. The invention relates to a supercapacitor production method in which all components of supercapacitors used in the field of energy storage are prepared by using waste fabrics, is characterized by comprising the steps- Collecting waste fabrics,- Carbonizing the waste fabrics in a heat treatment furnace under N2 gas atmosphere to obtain current collector and separator,- Mixing the carbonized waste fabrics with activation chemicals,- Activating the waste fabric - activation chemical mixture in a heat treatment furnace under N2 gas atmosphere,- Washing and drying the activated carbon samples obtained after activation with distilled water until the pH value reaches 7,- Washing the dried samples first with hydrochloric acid (HC1) and hydrogen fluoride (HF) respectively,- Preparing the electrode material by washing and drying again with distilled water until the pH value reaches 7,- Cutting the waste fabric samples into small pieces and drying them to remove moisture,- Mixing the dried waste fabric pieces with a solution of protic ionic liquid containing triethylammonium hydrogen sulfate and water,- Pretreatment of the mixtures by heating in a stainless steel high pressure reactor,- After heating, ethanol is added to the mixture, filtered, washed with distilled water until the pH value reaches 7 and dried in vacuum to obtain cellulose,- Transferring the produced cellulose to NaOH-urea aqueous solution, stirring and holding the solution at room temperature,- Then stirring the solution at room temperature until it becomes homogeneous and transparent, adding sulfuric acid (H2SO4) to thesolution and coagulating the cellulose hydrogel and removing it from other media components,- Preparation of the electrolyte by washing the produced hydrogel with deionized water and removing impurities,- Mixing the activated carbon samples with carbon black in ethanol,Spraying the prepared mixture on the current collector prepared from waste fabric with the help of a spray gun,- Preparation of the electrodes of the supercapacitor cell by drying the current collectors sprayed with activated carbon-carbon black mixture in a vacuum oven,Spreading the electrolyte on the prepared electrode surfaces,- Placing the separator made of waste fabric between the two prepared electrodes,- Placing the structure containing the two electrodes, electrolyte and separator in the antistatic bag,- Discharging the air in the bag,- Closing the bag with a bag sealing machine to complete the packaging process.

2. The invention relates to a supercapacitor production method as in claim 1, characterized in that the waste fabrics are carbonized in a heat treatment furnace at temperatures in the range 200 - 700 °C in an atmosphere of N2 gas.

3. The invention relates to a supercapacitor production method as in claim 1, characterized in that the activation chemicals are phosphoric acid (H3PO4), potassium hydroxide (KOH), potassium carbonate (K2CO3), sodium hydroxide (NaOH), sodium carbonate (Na2CO3) or zinc chloride (ZnCh).

4. The invention relates to a method of manufacturing a supercapacitor as in claim 3, characterized in that the activation chemicals are mixed in a ratio of 1 : 1, 1 : 1.5, 1 :2, 1 :2.5, 1 :3, 1 :3.5, 1 :4, 1 :4.5 and 1 :5 by mass.

5. The invention relates to a method of manufacturing a supercapacitor as in claim 1, characterized in that the supercapacitor is activated in an N2 gas atmosphere at temperatures between 450 °C and 900 °C for 1 to 2 hours.

6. The invention relates to a supercapacitor production method as in claim 1, characterized in that the dried samples are washed with 1 M hydrochloric acid (HC1) and 1 M hydrogen fluoride (HF).

7. The invention relates to a method of manufacturing a supercapacitor as in claim 1, characterized in that it is mixed with a solution of a protic ionic liquid comprising 80 wt% triethylammonium hydrogen sulfate and 20 wt% water.

8. The invention relates to a supercapacitor production method as in claim 1, characterized in that the mixtures are heated in a stainless steel high- pressure reactor at temperatures between 125 °C and 225 °C.