WO2020013547A2 - Device for simultaneously producing water vapor and electricity - Google Patents

Abstract

The present invention relates to a device for simultaneously producing water vapor and electricity, which has a simple structure and an excellent electricity generation efficiency and can simultaneously produce water vapor and electricity even if a separate device is not added, and, more specifically, to a device for simultaneously producing water vapor and electricity, which has a metal electrode as a first electrode and has, as a second electrode, a carbon structure layer deposited on a porous hydrophilic polymer base material with the structure of a hollow cone, pyramid, truncated cone, or truncated pyramid, and which is used in a state in which the bottom surface of the hydrophilic polymer base material is in contact with and floats on the water in which the first electrode is submerged.

Description

Equipment for the simultaneous production of steam and electricity

The present invention is capable of simultaneous production of steam and electricity without merging separate devices, and relates to a device for simultaneously producing steam and electricity having a simple structure with excellent electricity production efficiency.

As traditional fossil energy is depleted and interest in environmental issues is raised, pollution-free renewable energy, which acquires energy that is transformed or extinguished in its natural state and converts it into usable energy, has been proposed as an effective solution to the energy crisis. Renewable energy sources include wind, sun, geothermal and water. Solar energy has received the most attention because of its universal, clean, environmentally friendly, and sustainable characteristics, and has been widely used in the production of hydrogen, power generation, photocatalysts, water purification, and desalination. The annual solar energy reaching the Earth's surface is about 2.85 million EJ, which is a vast energy source that is about 10,000 times the world's annual energy consumption. Nevertheless, the use of solar energy is still very limited. Water is a promising and attractive source of energy that is present in a wide and abundant way in our bodies as well as in rivers, lakes, and the sea. Conventionally, large and complex devices such as dams and aberrations have been commonly used to harvest enormous energy from running water. However, they are not applicable to biomedical devices that require personal use, miniaturization, or implantability. Therefore, the development of miniaturized, high-efficiency generators remains a challenge in the field of renewable energy using water.

In 2001, Kral and Shapiro (Phys. Rev. Lett. 2001, 86, 131-134) proposed that current could be generated from metallic carbon nanotubes (CNTs) contained in flowing liquid through theoretical calculations. Later, in 2003, Sood et al. (Science 2003, 299, 1042-1044) discovered that voltage was induced in the sample along the flow direction of the liquid on a single-walled CNT bundle. Guo et al. (Nat. Nanotechnol. 2014, 9, 378- 383) reported that a voltage of several mV was generated by the movement of droplets of seawater or ionic solution moving on a single layer of graphene under atmospheric conditions. Nanogenerators based on macroscopically arranged CNT yarns, twisted and stretched polymer muscles, arrayed multiwalled CNT sheets, superhydrophilic 3D graphene oxide (GO) frameworks, and GO-metal nanohybrid materials ) Were developed. However, in order to generate electricity, the nanogenerators need not only separate energy and / or complicated equipment for water to flow, but also further increase the low current density generated by the problem of using a carbon material having low electrical conductivity. It has a fundamental problem that cannot be solved. Thus, these nanogenerators are suitable for producing very little power.

Water evaporation, on the other hand, is a very common and natural phenomenon of harvesting heat energy from the atmosphere. Steam production by evaporation of water has also been used in energy harvesting equipment. Traditionally, fossil fuels were used to produce a large amount of water by heating a large amount of water in a steam engine, but recently, a solar-induced steam production system that produces water vapor from sunlight using a highly efficient absorber that converts sunlight into heat. This is attracting attention.

However, even with such a solar-induced steam production system, in order to obtain electricity from evaporation of water, a device for generating water vapor from sunlight must be integrated with a separate device for electricity production, and the amount of electricity obtained is also limited. For example, Ho et al. (Adv. Energy Mater. 2018, 1702149) used a ferroelectric polyvinylidene fluoride (PVDF) to harvest thermomechanical reactions from carbon sponge photo-evaporation. Ma et al. (Nano Energy 2016, 22, 19-26) reported a self-contained polymer pyroelectric nanogenerator by steam without other energy devices. Zhou et al. (Adv. Energy Mater. 2018, 1702149) achieved a maximum photothermal efficiency of 75% at 1 sun irradiation by employing a CNT-modified filter paper and a hybrid system based on commercial Nafion membranes. Induced power of m 2. Nevertheless, they have a problem in that the system is complicated because two devices must be combined. In addition, since these systems can generate water vapor only by light, electricity cannot be produced under dark conditions, or even relatively low electricity is produced.

On the other hand, a metal air battery using a metal such as iron, zinc, aluminum as a cathode, an anode as an anode, and oxygen in the air as a cathode active material is attracting attention as a high energy density battery. Metal air cells use cheap metal as a negative electrode and use carbon and oxygen instead of metal oxides inside the battery, and have a much higher energy density than conventional secondary batteries, and are light in weight and have high practicality. The capacity of lithium air batteries in metal air batteries is known to reach 5 to 10 times that of lithium ion batteries. However, there is a problem in that 1/3 of the charged electricity is lost due to heat, there is a risk of rising electrode temperature, and the storage period of power is not long.

An object of the present invention is to provide an apparatus capable of efficiently producing water vapor and electricity simultaneously in one apparatus having a simple structure even without merging two apparatuses.

The present invention for achieving the above object is a metal electrode as a first electrode, a carbon structure layer deposited on a porous hydrophilic polymer substrate having a hollow cone, pyramid, truncated cone or pyramidal structure as a second electrode, And a bottom surface of the hydrophilic polymer substrate in contact with water in which the first electrode is immersed and used in a suspended state.

In the present specification, the "top" of the cone and pyramid means the carbon structure layer on the outer surface, and the "bottom" means the hydrophilic polymer substrate side.

In addition, in the present specification, the "apex angle" of the cone refers to the angle between two lines that form the vertex of the cone at the vertex of the cone, and the "vertical angle" of the cone refers to the angle between two lines forming the virtual vertex of the cone. do. The "vertical angle" of the pyramid is defined as the average value of the angle between the vertices and two adjacent sides on each oblique plane, and the "vertical angle" of the pyramid is defined as the average value of the angles between the two sides that form the virtual vertices on each oblique plane.

As used herein, the "bottom" of the polymeric substrate refers to the portion opposite to the (virtual) vertex of the cone (large) or pyramidal (large).

The device of the present invention is used in a state of being suspended in water, and is characterized by being able to simultaneously produce steam and electricity in one device without merging separate devices due to the material and structure. The device of the present invention is due to the combined action of a conventional solar induction production system and a nanogenerator and a metal air cell in which electricity is generated by the movement of droplets on a carbon structure. In the apparatus of the present invention, the current is mainly generated by the metal air cell in the state that light is not irradiated, and under light irradiation, the generation of water vapor is increased by the light irradiation by the absorber, thereby increasing the current generation rate of the nanogenerator.

In the device of the present invention, the first electrode serves as the first electrode of the nanogenerator and the anode of the metal air electric. The first electrode may be one metal selected from the group consisting of Fe, Zn, Al, Ni, and Mg or an alloy of two or more metals.

In the device of the present invention, the second electrode is characterized in that the carbon structure layer formed on the porous hydrophilic polymer substrate, the nano-generator for generating a current on the surface of the carbon structure by the flow of the absorber, droplets of sunlight It serves as the anode of the second electrode and the metal air battery. In the device of the present invention, the porous hydrophilic polymer substrate not only functions as a support for the carbon structure but also serves to continuously provide moisture by capillary action. In the following examples, only the paper is exemplified as a hydrophilic polymer material, but any material can be used as long as the water can be moved through the porous structure. That is, the hydrophilic polymer may be a natural polymer or a synthetic polymer, selected from the group consisting of paper or cotton, cellulose resin, polyacrylonitrile, polyvinyl alcohol, polyamide, polyethersulfone, polyethylene glycol and hydrophilic polyurethane It may be made of one or more, but is not limited thereto. In order to further increase conductivity, the polymer may be in the form of crosslinking with a polymer electrolyte including an ionic liquid polymer.

It is preferable that the thickness of the said porous hydrophilic polymer base material is 1 micrometer-5 mm. If the thickness of the substrate is too thin, the stability as a support may be insufficient and the water supply amount may be limited, and if the thickness of the substrate is too thick, heat loss may occur. The optimum thickness may be set in consideration of the porosity, the size of the pore, and the gap between the pores according to the material, which will be easy for those skilled in the art. The pore size, spacing between voids, and porosity can also be easily set to optimum conditions according to the material and the detailed structure.

The apparatus of the present invention operates as a metal air cell using a metal as a first electrode and a carbon structure layer as a second electrode to oxidize the metal at the first electrode and generate electricity by reducing oxygen in the air at the second electrode. . In addition, the heat generated by the operation of the metal air cell evaporates water in the carbon structure layer to produce water vapor, thereby controlling the temperature of the carbon structure layer surface to prevent overheating. In addition, the carbon structure formed on the hydrophilic polymer substrate exhibits high absorbance for light of a wide range of wavelengths and has high photothermal conversion efficiency, so that water supplied by the irradiated light can be efficiently evaporated to produce water vapor. Since the flow of water on the surface of the carbon structure generates electricity as is known in the art, the flow of water on the surface of the carbon structure, also caused by the evaporation of water vapor, in the apparatus of the present invention further generates electricity. This interaction allows for the simultaneous production of water vapor and electricity in one device without merging a separate device for the flow of water and a separate device for the generation of electricity.

The carbon structure increases the light-heat conversion efficiency during light irradiation, induces electricity by introducing an electrolyte by the flow of water, and carbon black, fullerene, carbon nano which can induce a reduction reaction using oxygen as an active material. One or more selected from the group consisting of tubes, graphene, carbon dots, carbon fibers and conductive carbon can be used. In the following examples, only carbon nanotubes are exemplified, but other carbon structures may also induce electricity by introducing an electrolyte by the flow of water, and thus may act as a positive electrode of a metal air battery. Applicability is natural.

It is preferable that the thickness of the carbon structure layer is 10 to 100 μm. As the thickness of the carbon structure layer increases, the photothermal conversion efficiency increases, so that the rate of steam generation increases, and the supply of the electrolyte is accelerated as the rate of steam generation increases. Therefore, if the thickness of the carbon structure layer is too thin, water vapor and electricity production efficiency is reduced, it is preferable that the thickness of 10 ㎛ or more. On the other hand, as the thickness of the carbon structure layer increases, the porosity decreases, and when the thickness is 100 μm or more, it is difficult to form a uniform carbon structure layer. However, if it is possible to form a uniform layer having a porosity even if thicker than 100 μm, it is not excluded.

Forming the carbon structure layer on the substrate may include, for example, drop coating, screen printing, coating with a doctor blade, spraying, or vacuum depositing a dispersion of the carbon structure, Various methods such as dip coating on the dispersion can be used, and any method may be used as long as the carbon structure layer can be uniformly formed on the substrate.

In the vacuum deposition method used in the following examples, the carbon structure layer is formed only on one side of the substrate, but for example, the carbon structure layer may be formed on both sides of the substrate by immersion coating or by vacuum deposition on both surfaces.

The device of the present invention is structurally in the form of a cone, pyramid, cone or pyramid. The cone can also be a staff cone, including the rain cone. Pyramids also include orthogonal pyramids and comb pyramids. In the following, the apparatus of the present invention will be described by illustrating a conical structure for convenience of description.

Due to the three-dimensional cone structure, the device of the present invention has a wider surface area than a simple absorber having a flat shape, and can absorb a large amount of light regardless of the direction, thereby increasing water vapor production efficiency.

In addition, the device of the present invention has a higher temperature at the top when irradiated with light than the bottom (the radius of the circle which is the horizontal cross section of the cone), so that the evaporation rate of water is higher near the vertex than the bottom, so that in addition to the capillary force, More water is generated by causing the flow of water from the bottom to the vertex, facilitating the introduction of electrolyte into the pores between the two electrodes. In the apparatus of the present invention, the more the movement of water is, the more efficient electricity production is. Therefore, when the second electrode is connected to the electric wire, it is more preferable to connect the vertex side of the cone or the pyramid, and the near side of the truncated cone or the pyramid to the smaller cross section.

The cone angle of the cone also affects the water vapor and electricity production efficiency. If the vertex angle is too large or too small, the effect of the conical structure is reduced, reducing the efficiency of water vapor and electricity production. Therefore, it is preferable that the vertex angle of a cone is 10-170 degrees.

The cone has the additional advantage of being able to stably float in water due to the air filled in the lower space. The truncated cone has a truncated vertex of the cone, which reduces the evaporation area of water vapor compared to the cone, while vaporization of water vapor may occur on both sides of the substrate, so that water vapor and electricity can be effectively produced simultaneously. Orthogonal pyramids or polygonal pyramids can be produced simultaneously with water vapor and electricity by the same principle.

The device of the present invention operates as a metal air cell to generate electricity, and at the same time, water moved through the porous structure of the substrate, the carbon structure layer, and the hydrophilic polymer layer acts as an electrolyte by evaporation of water absorbed in the water. Electricity is generated due to the potential difference between the carbon structure electrode and the metal wire. Due to the characteristics of the conical structure described above, it is possible to produce electricity regardless of light irradiation because it is possible to produce water and electricity even under dark conditions. Since the evaporation of water vapor is more active under light irradiation conditions and the movement of water on the surface of the carbon structure is increased compared to the dark conditions, the device of the present invention is characterized by It is expected that the contribution will increase.

At this time, the device of the present invention, when the electrolyte is dissolved in the suspended water, it is more excellent in electricity production capacity. The type of the electrolyte also affects the electrical output of the device according to the present invention, and the output was excellent as the size of the anion increased. The cation output was high in the order of K ⁺ > Ca ²⁺ > Na ⁺ when irradiated with light and Ca ²⁺ > K ⁺ > Na ⁺ under dark conditions. It will be easy to set the optimal concentration according to the type of electrolyte. When 0.6M NaBr was used as an electrolyte in the metal-air battery according to the following example, the output power at 1 sun brightness was 505.69 mW / m 2, which was higher than that of any hybrid system of the prior art.

In order to further improve the output or voltage of the device of the present invention, it is natural that a plurality of devices can be electrically connected and used in series or parallel connection as in a conventional battery. In the embodiment of connecting four devices by series connection, the open circuit voltage was observed for 55,000 seconds (~ 15.3 hours), and it was confirmed that stable voltage supply was possible.

As described above, according to the apparatus for simultaneously producing water vapor and electricity, the hydrophilic porous structure of cellulose and carbon nanotubes, while acting as a metal air cell, provides an ideal channel for the flow of water, and is located above the lower portion of the conical structure. Because of the high speed of steam generation at, the flow of water from the lower part of the conical structure to the upper part is induced. Therefore, it does not need to consume extra energy to induce water flow. And electricity can be produced simultaneously with excellent efficiency.

In addition, the device for simultaneous production of water vapor and electricity of the present invention can produce steam and electricity even in dark conditions because energy lost by heat in the conventional metal ion battery contributes to water vapor production, thus enabling operation without distinction between night and day, and producing steam. Due to this, the temperature of the electrode surface can be maintained at a constant temperature, and thus can be used more safely.

In addition, the water vapor and electric simultaneous production apparatus of the present invention has a simple structure without a complicated device, economical mass production, free to scale, stable to a wide range of light, does not use toxic substances, biodegradable It is excellent and can be used as an environmentally friendly alternative energy production means.

Figure 1 is a photograph of a device for the simultaneous production of carbon nanotubes deposited cellulose structure and conical structure vapor and electricity produced by an embodiment of the present invention.

Figure 2 is a SEM, TEM image and XPS, Raman and UV spectrum showing the physical and chemical properties of the cellulose structure deposited carbon nanotubes according to an embodiment of the present invention.

Figure 3 is a photograph and infrared photographs of the experiment for evaluating the steam production efficiency of the steam and electricity simultaneous production apparatus according to an embodiment of the present invention.

Figure 4 is a photograph of a cellulose structure prepared according to the thickness of the carbon nanotube layer in one embodiment of the present invention.

5 and 6 are photographs and graphs showing the water vapor production efficiency of the device for simultaneous production of water vapor and electricity according to the thickness of the carbon nanotube layer.

7 and 8 are graphs showing the steam production efficiency according to the vertex angle of the conical structure of the device for simultaneous production of steam and electricity.

9 is an experimental photograph and a result graph for evaluating the electrical production efficiency of the steam and the apparatus for the simultaneous production of electricity according to an embodiment of the present invention.

Figure 10 is a photograph and graph showing the three-dimensional structural efficacy of the apparatus for simultaneous production of water vapor and electricity of the present invention.

11 is a graph showing the electricity production efficiency of the device for simultaneous production of water vapor and electricity in various electrolyte solutions.

12 is a graph and an experimental photograph showing the electricity production efficiency of the device for the simultaneous production of water vapor and electricity connected in series and parallel connected.

Hereinafter, the present invention will be described in more detail with reference to the accompanying examples. However, such an embodiment is only an example for easily describing the content and scope of the technical idea of the present invention, whereby the technical scope of the present invention is not limited or changed. It will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the present invention based on these examples.

EXAMPLE

Example 1 Preparation of a Cone Structure Device for Simultaneous Production of Steam and Electricity

Multi-walled carbon nanotubes (MWCNTs, Hanwha Nanotech) were heat-treated in air at 300 ° C. for 60 minutes. Thereafter, after mixing with 37% hydrochloric acid and sonicating for 1 hour, the process of filtering and washing with distilled water until the pH of the filtrate became neutral was repeated five times. Then purified by drying for 24 hours in a 70 ℃ oven.

MWCNTs were coated on cellulose filter paper by vacuum assisted deposition using a solution of 20 mg of purified MWCNTs in 200 ml DI water and dried at 70 ° C. for 24 hours.

The MWCNT-coated cellulose was used to make a cone structure from a 2/3 circle to a cone angle of 60 ° and a bottom diameter of 18 mm, and the interface was bonded using epoxy resin. Electrodes were connected to the vertices of the cone through wires and floated in water, and the wires to be used as the first electrode were limited to cellulose to limit their movement to prevent contact with the carbon structure layer, which is the second electrode. Fixed to filter paper. As a result, the first electrode is in contact with water, but is insulated from the carbon structure layer.

Figure 1 a) and b) is a picture of the cellulose coated with MWCNT and the conical structure using the same and the apparatus for the simultaneous production of electricity.

Example 2 Structural Characterization of Cellulose Structures Coated with Carbon Nanotubes

Morphology and thickness of carbon nanotubes adsorbed on cellulose filter paper were measured by high resolution scanning electron microscope (HRSEM; Hitachi S-4800, Hitachi) and transmission electron microscope (TEM; JEM-2100F HR, JEOL). The structure was observed at 10 ^-10 Torr with a Multilab 2000 spectrometer equipped with monochromatic Al Kα (1486.65 eV) X-ray radiation. The binding energy scale was calibrated to the binding energy position of Au 4f _7/2 core level at 83.98 eV. Raman spectra were recorded with a 532 nm DPSS laser.

FIG. 2 shows the results, in which the SEM image of a) shows that a 72 μm thick MWCNT film is obtained on a cellulose fiber film. b) shows the surface image of MWCNT, suggesting that the porous structure is formed by both MWCNT cellulose papers and can act as an ideal channel for water supply. X-ray photoelectron (XPS) spectra of c) show the presence of O—C═O, C═O, and C—O bonds on the surface of the MWCNT, which was also confirmed by FTIR (Thermo Scientific) (data not shown). Guo et al. Reported that charge rearrangement is caused by the adsorption of water onto graphene flakes with different functionalities through calculations using density function theory (DFT). According to the calculation result, a charge double layer is formed at the interface between water and graphene. When three layers of water are covered in the C-O-C group, about 0.7e is consumed, and when the C-O-C group is removed, it falls to 0.003e. Therefore, such functional groups of MWCNTs are essential for the generation of electricity.

The MWCNT consists of loosely stacked disordered graphene flakes can be seen in the TEM image of d), which can also be seen in the Raman spectra of e). As a result of measuring the contact angle of the structure prepared in Example 1, it was confirmed that the MWCNT thin film exhibits hydrophilicity, which means that water may move by capillary phenomenon along the porous structure of the MWCNT in addition to the cellulose support.

According to the prior art, the interaction of water with MWCNTs, in particular the flow of water induced by the evaporation of water inside the porous MWCNT film, is considered the main reason for the generation of electricity. Therefore, when the conical structure is manufactured using the structure manufactured according to the above embodiment, the water flows to the upper portion of the structure by capillary action as the water is evaporated by sunlight or by self-evaporation. It is expected to be able to generate steam and electricity at the same time without using a separate device because it can generate electricity.

2) shows the results of measuring the refractive and transmissive properties of the absorber using a UV-Vis-NIR spectrometer (Solidspec-3700, Shimadzu) to evaluate the solar absorption efficiency. In this figure, the structure has a transmittance of 250 to 800 nm, and it can be seen that light of a wide range of wavelengths is blocked by MWCNT.

Example 3 Evaluation of Steam Production Capacity in the Laboratory of Simultaneous Production of Steam and Electricity

1) Steam production capacity evaluation device

In order to calculate the photothermal conversion efficiency of the steam and the device for the simultaneous production of electricity produced in Example 1, a device for evaluating the steam production capacity by 1 sun irradiation as a real-time weight change was designed.

To measure the water evaporation rate of water vapor and electrical co-production equipment, a 50 mL container coated with polystyrene foam was placed on a scale connected to a computer and simulated with sunlight (350-1800 nm, solar simulator, Hal 320 W, ASAHI). ). Place a polystyrene foam (EPS) dish expanded to 2 × 2 cm into a cup coated with polystyrene foam on the inner wall, place a 2 × 4 cm white cellulose paper in the center of the EPS dish, and fold both ends inwards. It can be locked. The device of conical structure was placed on paper and water was placed in the cup so that both ends of the paper were submerged while the water level was below the EPS dish. The top of the vessel was covered with polystyrene foam to minimize evaporation of water in the gap between the apparatus and the vessel. The height above the water surface of the conical device was 16 mm, and the distance from the top of the cone to the interface between water and air was 8 mm. When the device was completely wet the simulated sunlight was turned on and weighed every 10 seconds to calculate the amount of evaporation. Temperature changes during evaporation were measured using a thermal imaging camera (SEEK) and K thermocouple temperature probe (Testo735).

Figure 3 a) is a representative optical image of the experimental apparatus for evaluating the steam production capacity, b) and c) is a representative infrared image of the cone structure device when irradiated with light of 1 sun intensity for 30 minutes. At the experiment, the ambient temperature was 22 ℃ and the relative humidity was 40%. The surface temperature of the device during self-evaporation was similar to the ambient temperature. However, at 1 sun light irradiation, after 30 minutes of light irradiation, the temperature of the device increased to 34 ° C., and the temperature decreased as the top of the conical structure was the highest and lowered. Therefore, the evaporation rate of water increases as the conical structure is moved upward, thereby facilitating the movement of water from the lower part of the absorber to the upper part.

2) Evaluation of water vapor production capacity according to the thickness of CNT layer

Using the device designed in 1), the effect of the thickness of the CNT layer on the steam production was evaluated. To this end, 100 mg of MWCNT purified in Example 1 was suspended in 1000 ml DI water, and then each solution was coated with MWCNT on a cellulose filter paper by vacuum assisted deposition using 50, 100, 200 or 300 ml, and 70 ° C. After drying for 24 hours at the same manner as in Example 1 to prepare a cone structure device for the simultaneous production of water vapor and electricity.

4 is a photograph of a structure in which MWCNTs are deposited by the above method, and when a 300 ml solution is used, a uniform MWCNT layer is not formed. Thus, the water vapor production capacity was evaluated by the same method as 1) using conical structures prepared using 50, 100 and 200 ml of solutions, respectively, and the results are shown in FIGS. 5 and 6.

5 a) to d) are SEM images of cellulose and cellulose on which MWCNTs are deposited. As the amount of MWCNT solution increases, the thickness of the MWCNT layer gradually increases to 31, 50, and 72 μm, while the porosity decreases. Shows. e) shows the solar spectrum and absorbance of each sample. The absorbance of cellulose with MWCNT layers with thicknesses of 31, 50 and 72 μm was 98.1, 98.5 and 98.4%, respectively, showing good absorbance for a wide range of wavelengths at all thicknesses. It was. On the other hand, the absorbance of cellulose without MWCNT layer was very low. f) is the temperature of the top of the cone structure when the cone structure is irradiated with 1 sun luminescence in the absence of water. The temperature of the equilibrium temperature is 45 ~ 50 ℃ within 3 minutes when the MWCNT layer is formed. Shows rising.

When the water vapor and electric co-production apparatus was floated in water, the maximum temperature was slightly decreased, as shown in FIG. 6 a). In the absence of water, the absorbed energy was released as heat, but in the presence of water, It is believed to be used. In the floated device, it took about 200 to 300 seconds to equilibrate the temperature. Zhao et al. (Nat. Nanotech., 2018, doi: 10.1038 / s41565-018-0097-z) reported that the correlation between surface temperature and time in different energy consumption patterns differs. Therefore, most of the energy was used to increase the temperature in the early rapid temperature rise period, and then it was interpreted that energy was mainly used for evaporation in the equilibrium period. The thicker the MWCNT layer, the higher the surface temperature. b) identifies the inflection point of the temperature-time graph, showing the presence of energy balance values for water heating and evaporation. It can be predicted that the thicker the MWCNT layer, the lower the inflection temperature will increase, thus increasing the evaporation efficiency of water. c) and d) are graphs showing the amount of steam produced and the rate of production, showing that the amount of vapor produced or the rate of vaporization increases as the thickness of the MWCNT layer increases. As the thickness of the MWCNT layer increased from 0 to 72 μm, the evaporation rate increased from 0.439 to 1.651 kg / m 2 .h at 1 sun light irradiation.

In addition, in Figure 6 d) it was confirmed that the vapor evaporation occurs not only at the time of light irradiation but also in the dark conditions, which means that the steam can be generated both day and night by operating as a metal air cell.

3) Evaluation of steam production capacity according to the vertex angle of the device for simultaneous production of steam and electricity

Conical metal-air battery with vertices of 45, 60 and 90 ° using cellulose deposited with MWCNT prepared in Example 1 to determine the effect of conical structure of steam and electricity co-production apparatus on steam production Was prepared.

7 a) shows the temperature change when the water vapor and the device for the simultaneous production of light at 1 sun light intensity, the internal view shows the temperature change (left) and the inflection point (right) without water ) Is shown. According to a), when the angle of vertex is 60 °, the inflection temperature is the lowest, so it can be predicted that the steam production rate will be the highest. 7 b) and 8 a) of the actual measurement results, it can be seen that the water vapor production capacity of the cone structure device having a vertex angle of 60 ° is the highest, and the dark condition and 1 in the cone structure device having a vertex angle of 60 °. The evaporation rates during sun light irradiation were 0.618 and 1.651 kg / m 2 .h, respectively.

8B shows the evaporation rates according to the thickness of the MWCNT layer and the vertex angle of the cone structure during light irradiation. The internal figure shows the evaporation rate at the time of self evaporation.

Example 4 Evaluation of Electric Production Capacity in the Laboratory of Simultaneous Production of Water Vapor and Electricity

1) Electricity Production Evaluation

In order to evaluate the electrical production capacity of the cone structure prepared in Example 1, the cone structure device prepared in Example 1 was floated in a Petri dish containing DI water. After connecting the electrodes to the bottom and top wires, current and voltage signals were collected and recorded on the potentiometer (IVIUMSTAT) through the J-t curve (interval: 10 seconds) and V-t curve (interval: 10 seconds), respectively.

9 a) is a schematic diagram of the present experiment, b) is an actual experimental photograph. 9 c is an output curve calculated from an I-V curve and an I-V curve at light conditions of 1 sun light and dark conditions measured by the experiment of b). As the open-circuit voltage and the short-circuit current increased in the case of 1 sun light irradiation, the output power at 1 sun light intensity of the device of Example 1 was 13.18 mW / m 2, which is 8.24 mW / m 2. It is 1.6 times higher than.

The output under dark conditions contributes to the production of electricity by operation as an air ion cell, and to the electricity generation of the nanogenerator due to the movement of water due to the generation of water vapor due to heat and natural drying generated during operation of the air ion cell. It is interpreted as. In the light irradiation conditions, the output by the nano-generator increases as the movement of water due to the generation of water vapor increases, it can be seen that the total output increases in the light irradiation conditions compared to the dark conditions.

2) Efficacy evaluation by structure in the device for simultaneous production of water vapor and electricity

The cone structure and the rectangular device were used to further verify the effect of the cone structure on the electrical production capacity.

To this end, MWCNT was vacuum-deposited on cellulose by the same method as in Example 1, and a rectangular and triangular structure was prepared using the same height and base diameter of the cone. The upper and lower portions of the rectangular and triangular metal-air batteries were connected to the electrodes through wires, respectively. As in Example 1, the iron wire connected to the bottom was first coated with epoxy resin on the MWCNT so that the iron wire was in contact with water but not directly with MWCNT.

The rectangular and triangular devices manufactured by the above method were used to evaluate the electrical production capacity under dark conditions. 10 is a graph showing the actual experiment and the resulting voltage over time.

In FIG. 10, it can be seen that the triangular device produces electricity of about 2 times higher voltage even though the total area is only 1/2 of the rectangular device. This means that a three-dimensional structure such as a cone, a truncated cone, a pyramid, and a truncated pyramid plays an important role in the apparatus for simultaneously producing water vapor and electricity.

3) Evaluation of electricity production capacity using electrolyte solution

Since water has a very low ion concentration, an electrolyte solution was used to determine whether the ions could improve the output of this steam and the apparatus for simultaneous production of electricity. The experiment was conducted by the same method as 1) except that the electrolyte solution was used instead of water.

11 is a graph showing the output of the device in various electrolytes. a) shows the output according to the concentration of NaCl. As the concentration of NaCl increases to 0.6 M, the output also increases, but decreases as the concentration of NaCl increases. This may be because NaCl precipitates as the water evaporates at the top of the cone structure when the NaCl concentration is too high. The power at 0.6 M NaCl was 107.79 mW / m 2, which is more than eight times better than the power at water.

As it was confirmed that the electrolyte was advantageous for the improvement of the output, the influence of the type of cation or anion on the output was identified. At this time, the concentration of the electrolyte was fixed at 0.6 M. 11 b) shows the effect of anions, c) shows the effect of cations, the output of the anion is improved as the size is increased, the output was improved to 255.67 mW / ㎡ using 0.6M NaBr. The cations did not show a trend in size, and showed a higher power than the conventional hybrid system at 505.69 mW / m 2 when 0.6M KCl was used. It is remarkable that the output under dark conditions also increases greatly with cations, resulting in 252.4 mW / m 2 using 0.6M KCl and 266.2 mW / m ₂ using 0.6M CaCl ₂ .

Pond water and sea water are known to contain various ions. The output was measured using water and seawater collected from Chungnam National University pond. d) shows the results, which also showed higher output than water.

4) Evaluation of electricity production capacity by series connection and parallel connection

The output of the water vapor and the device for the simultaneous production of electricity is expected to be amplified through a series connection and a parallel connection, and confirmed through the examples.

After manufacturing four devices of the same conical structure by the method described in Example 1, IV curves under dark conditions for each device and four devices connected in series and four devices connected in parallel And the calculated output curve from the IV curve. 12A and 12B are graphs showing the results. First, each of the four devices has excellent reproducibility with an open circuit voltage of 0.65 V and a short circuit current of 27 mA. The open circuit voltage of the device was amplified to 2.3V by the series connection, and the short circuit current increased to 120 mA by the parallel connection. c) is a photograph of a series-connected device and a graph showing the open-circuit voltage as a function of time, showing that the open-circuit voltage is maintained at 2.3 V for 55,000 seconds so that the device of the present invention can produce both substantially water vapor and electricity for long-term electricity production. It can be used as a device.

Claims (9)

1. The metal electrode as the first electrode,

   The second electrode is a carbon structure layer deposited on a porous hydrophilic polymer substrate having a hollow cone, a pyramid, a truncated cone or a pyramid structure.

   Simultaneous production of water vapor and electricity, characterized in that the first electrode is used in a floating state in contact with the bottom surface of the hydrophilic polymer substrate in contact with the water.
2. The method of claim 1,

   Wherein the first electrode is one metal selected from the group consisting of Fe, Zn, Al, Ni, and Mg or an alloy of two or more metals.
3. The method of claim 1,

   The hydrophilic polymer is water and electricity characterized in that at least one selected from the group consisting of paper, cotton, cellulose resin, polyacrylonitrile, polyvinyl alcohol, polyamide, polyethersulfone, polyethylene glycol and hydrophilic polyurethane Equipment for simultaneous production.
4. The method of claim 1,

   The carbon structure is at least one selected from the group consisting of carbon black, fullerenes, carbon nanotubes, graphene, carbon dots, carbon fibers and conductive carbon, the apparatus for simultaneous production of water vapor and electricity.
5. The method according to any one of claims 1 to 4,

   The carbon nanotube layer is a device for the simultaneous production of water vapor and electricity, characterized in that 10 ~ 100 ㎛ thickness.
6. The method according to any one of claims 1 to 4,

   The cone, pyramid, truncated cone or the vertex angle of the pyramid is a device for the simultaneous production of steam and electricity, characterized in that 10 ~ 170 °.
7. The method according to any one of claims 1 to 4,

   The apparatus for simultaneously producing steam and electricity is characterized in that the apparatus for producing steam and electricity simultaneously, characterized in that it produces electricity regardless of light irradiation.
8. The method according to any one of claims 1 to 4,

   The device for simultaneous production of water vapor and electricity, characterized in that the electrolyte is dissolved in the water.
9. An apparatus for simultaneous production of steam and electricity, comprising connecting the steam and the apparatus for simultaneous production of electricity according to any one of claims 1 to 4 in series or in parallel.

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