Polar liquid capacitor with spontaneously and sharply increased relative permittivity

Abstract

The invention relates to a polar liquid capacitor with spontaneously and sharply increased relative permittivity, which comprises two electrodes close to each other and an insulating dielectric medium positioned between the two electrodes, and the insulating dielectric medium is polar liquid. Polar liquid refers to liquid with misaligned positive and negative charge centers in molecules, is a non-ionic compound, and generally has relatively high relative permittivity and dipole moment, so that special physical properties are shown, and the polar liquid capacitor with super-large relative permittivity and capacitance value is easy to obtain.

Description

Technical Field

[0001] The invention relates to the field of capacitors and is a polar liquid capacitor with a spontaneous and sharp increase in relative permittivity. Background Art

[0002] Permittivity is also called dielectric constant. In electromagnetism, it is a measure of the polarization of a dielectric in response to an external electric field. In a non-vacuum, since the dielectric is polarized, the total electric field inside the material will decrease. Permittivity is related to the ability of the dielectric to transmit the electric field. Permittivity measures how the electric field affects the dielectric and how it is affected by the dielectric. Vacuum Permittivity ε0 = 8.857 × 10 -12 F / m, relative permittivity ε r It is the ratio of the permittivity ε to the absolute permittivity ε0 in vacuum.

[0003] Conventional capacitors are electronic components consisting of two conductors close to each other with a layer of non-conductive insulating medium in between. When voltage is applied between the two plates of the capacitor, the capacitor will store charge. In actual use, it is generally required that the capacitance of the capacitor changes as little as possible with temperature and electromagnetic field. Capacitors classified by dielectric are: ceramic capacitors (CC), polyester capacitors (CL), polystyrene capacitors (CB), mica capacitors (CY), paper capacitors (CZ), aluminum electrolytic capacitors (CD), etc. The dielectrics of conventional capacitors are all solid materials. For example, the relative permittivity at 25°C is: ceramic (6), mica (5.4), polyethylene (2.26), barium strontium titanate (1×10 4 ) etc., among which barium strontium titanate etc. have a very large relative permittivity, because when the external electric field drops to zero, the arrangement direction of the partial electric dipole moment inside the material is still consistent, the polarization strength is still maintained, there is a residual polarization electric field, and it has ferroelectricity, which makes the relative permittivity increase dramatically. Therefore, conventional capacitors use the residual polarization electric field of ferroelectric materials to obtain a very large relative permittivity. However, no capacitors whose relative permittivity increases dramatically spontaneously due to electrode materials have been found.

[0004] Supercapacitors (also called double-layer capacitors) are components that store energy through the interfacial ion double layer formed between electrodes and electrolytes. When the charged electrode contacts the electrolyte, the potential applied to the positive plate attracts negative ions in the electrolyte, and the negative plate attracts positive ions, thereby forming an ionic double-layer capacitor on the surface of the two electrodes. The double layer it forms is similar to the polarization charge generated by the dielectric in a conventional capacitor under the action of an electric field, thereby producing a capacitive effect. The compact double layer is similar to a flat plate capacitor element, but because the distance between the compact charge layers is much smaller than that between the charge layers of a conventional capacitor, it has a larger capacity than a conventional capacitor. The electrolyte of a supercapacitor is an ionic conductor. Under the action of an external electric field, an ionic double layer is formed on the electrode surface, and the relative permittivity is infinite. The dielectric is an insulating isolation membrane. However, no capacitors with spontaneous formation of a dipole layer on the electrode surface and a sharp increase in relative permittivity have been seen. Summary of the invention

[0005] In order to overcome the above shortcomings, the purpose of the present invention is to provide a polar liquid capacitor with a spontaneously increased relative permittivity to the art, so as to solve the technical problem of the existing capacitors with a spontaneously increased permittivity caused by the electrode material. The purpose is achieved through the following technical solution.

[0006] A polar liquid capacitor with a spontaneously increased relative permittivity, the capacitor comprises two electrodes close to each other and an insulating dielectric located between the two electrodes, characterized in that the insulating dielectric is a polar liquid. Polar liquid refers to a liquid in which the positive and negative charge centers in the molecule do not overlap, and is a non-ionic compound, usually having a high relative permittivity and dipole moment, thereby exhibiting special physical properties, and it is easy to obtain a polar liquid capacitor with a super large relative permittivity and capacitance value.

[0007] The electrodes are solid electrodes without an external electric field, and the materials of the two solid electrodes are the same or different.

[0008] The solid-state electrode is any one of gold, platinum, niobium and graphite.

[0009] The electric dipoles of the polar liquid overcome the intermolecular force and turn in an orderly manner under the action of the built-in electric field of the solid electrode / polar liquid. Bound charges appear at the interface of the solid electrode / polar liquid, and an orderly arranged dipole layer is formed on the surface of the electrode. The polar liquid generates a polarized electric field, and the relative permittivity of the polar liquid capacitor increases spontaneously. The two polarized electric fields each form two dipole layer capacitors, and the two dipole layer capacitors are in a parallel relationship.

[0010] The polar liquid is any one of water, ethanol and glycerol.

[0011] The present invention adopts polar liquid as the insulating dielectric of the capacitor to achieve a spontaneous sharp increase in relative permittivity, thereby obtaining a polar liquid capacitor with ultra-large relative permittivity and capacitance value, which is suitable for use as a capacitor in various fields such as energy storage devices and sensor devices, or an improvement of similar capacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural diagram of the polar liquid capacitor of the present invention and the measurement of its technical parameters.

[0013] Figure 2 This is a photo of the polar liquid capacitor of the present invention and an experimental device for measuring its technical parameters.

[0014] Figure 3 It is a schematic diagram of the spontaneous rapid increase mechanism of the relative permittivity of the polar liquid capacitor of the present invention, a is a schematic diagram of the electric dipole layer at the electrode / polar liquid contact interface, b is a schematic diagram of the dipole layer capacitance at the electrode / polar liquid contact interface, and c is a schematic diagram of the synthesized polar liquid capacitor.

[0015] The serial numbers and names in the figure are: 1. beaker, 2. polar liquid, 3. left electrode, 4. right electrode, 5. digital multimeter, 6. first resistor, 7. second resistor, 8. dual-channel platinum resistance temperature recorder. Implementation

[0017] The present invention will now be further described with reference to the accompanying drawings.

[0018] like Figure 1 , Figure 2 As shown, the polar liquid capacitor includes a beaker 1, which contains a polar liquid 5. The left electrode 3 and the right electrode 4, each with an area of ​​S, are immersed in the polar liquid 5 at a distance d to form a polar liquid capacitor. The measurement system adopts an electrostatic field measurement method, and the capacitance value of the polar liquid capacitor is directly measured using the capacitance range of a digital multimeter 5. A dual-channel platinum resistance temperature recorder 8, a second resistor 7 with a polytetrafluoroethylene tube is immersed in the polar liquid 5 to accurately measure the temperature of the polar liquid. The polytetrafluoroethylene tube can avoid affecting the polar liquid capacitor; the first resistor 6 is in the air outside the beaker 1 to keep the data of the two channels consistent and maintain the system temperature uniform and stable.

[0019] The electrode materials, polar liquid, container, and corresponding instruments in the embodiment of the polar liquid capacitor are as follows: 1. Electrode material: thickness is 0.1 mm, area S is 30×30 mm 2 , platinum Pt sheet, gold Au sheet and niobium Nb sheet with purity ≥99.99%; thickness 1mm, area S 30×30mm 21. Graphite C sheet with purity ≥99.9%; the distance d between the two electrodes is 3mm, and the electrode lead wires are all niobium Nb wires. 2. Polar liquids: ultrapure water (H2O), chemically pure ethanol (C2H6O) and glycerol (C3H8O3). 3. The container is a 100ml glass beaker. 4. The instruments are a digital voltmeter (17BMAX-01) and a high-precision dual-channel platinum resistance temperature recorder (YET-720L, resolution 0.001℃).

[0020] The above experimental results are shown in Table 1, which compares the conventional values ​​of polar liquids with the experimental values ​​of polar liquid capacitors at a temperature of 25°C.

[0021]

[0022] It can be found from Table 1 that the relative permittivity of polar liquid capacitors increases dramatically compared to conventional permittivity, which can be explained as follows based on the basic principles of physics and electrochemistry.

[0023] In addition to the properties of the dielectric itself, the relative permittivity is also related to temperature and electromagnetic field changes. Generally, materials with a relative permittivity greater than 2.8 are polar materials, and materials with a relative permittivity less than 2.8 are non-polar materials. The permittivity of an ideal conductor is infinite. The formula for calculating the plate capacitance of a conventional capacitor is: C = ε r ε0S / d, where C is the capacitance, S is the surface area of ​​the electrode, d is the distance between the two electrodes, ε0 is the vacuum permittivity, ε r is the relative permittivity. It can be seen that the relative permittivity of conventional capacitors is related to the area and spacing of the electrodes, and has nothing to do with the electrode material. At a uniform temperature, for a dielectric polar liquid composed of polar molecules, although each molecule can be regarded as an electric dipole and has a certain dipole moment, in the absence of an external electric field, due to the thermal motion of the molecules, the arrangement of the electric dipole moments of the molecules in the dielectric is disordered, so the dielectric does not show electrical properties to the outside. At this time, the relative permittivity of the polar liquid is the conventional value ε r .

[0024] like Figure 3 As shown in a, according to the solid / liquid interface double layer theory in electrochemical principles, any contact interface between two different materials has an internal potential difference, generating a built-in electric field. There is no charge diffusion exchange at the uncharged solid electrode / polar liquid contact interface. The electric dipoles of the polar liquid overcome the intermolecular forces under the action of the solid electrode / polar liquid built-in electric field and turn in an orderly manner. Bound charges appear at the solid electrode / polar liquid interface and form an orderly arranged dipole layer on the surface of the solid electrode, generating a polarized electric field in the polar liquid. Figure 3As shown in b, the orderly arranged dipole layers on the electrode surface each form two dipole layer capacitors. These two dipole capacitors are generated spontaneously. Because the dipole moment of the polar liquid is much smaller than the distance d between the two electrodes of a conventional capacitor, the dipole layer capacitance value is much larger than that of a conventional capacitor. The two dipole layer capacitors are in parallel, which makes the polar liquid capacitor have two more dipole layer capacitance values ​​than a conventional capacitor. Figure 3 As shown in c, the polar liquid capacitor C* adds two dipole layer capacitance values ​​to the capacitance value of a conventional capacitor. Thus, an extremely large relative permittivity and capacitance value as shown in Table 1 is obtained.

[0025] In summary, the solid electrode / dielectric built-in electric field of conventional capacitors is not enough to overcome the intermolecular forces of solid dielectrics to cause the dielectric molecules to rotate, while the solid electrode / polar liquid built-in electric field of polar liquid capacitors is enough to overcome the intermolecular forces of polar molecules to cause the polar molecules to rotate, change the direction of their own dipole moment, form an orderly arranged dipole layer on the electrode surface, and generate a polarized electric field, so that the relative permittivity of the polar liquid capacitor spontaneously increases sharply, and obtains an extremely large relative permittivity and capacitance value. The relative permittivity and capacitance values ​​are both directly measurable values. The relative permittivity of the new polar liquid capacitor spontaneously increases sharply, which greatly increases the sensitivity of the measurement and has application prospects in the field of capacitor sensors; it greatly increases the capacitance and has application prospects in the field of energy storage.

Claims

1. A polar liquid capacitor with a spontaneously increasing relative permittivity, the capacitor comprising two electrodes close to each other and an insulating dielectric located between the two electrodes, characterized in that The insulating dielectric is a polar liquid.

2. The polar liquid capacitor with spontaneous rapid increase in relative permittivity according to claim 1, characterized in that The electrodes are solid electrodes without an external electric field, and the materials of the two solid electrodes are the same or different.

3. The polar liquid capacitor with spontaneous rapid increase in relative permittivity according to claim 2, characterized in that The solid-state electrode is any one of gold, platinum, niobium and graphite.

4. The polar liquid capacitor with spontaneous rapid increase in relative permittivity according to claim 1, characterized in that The electric dipoles of the polar liquid overcome the intermolecular force and turn in an orderly manner under the action of the built-in electric field of the solid electrode / polar liquid. Bound charges appear at the interface of the solid electrode / polar liquid, and an orderly arranged dipole layer is formed on the surface of the electrode. The polar liquid generates a polarized electric field, and the relative permittivity of the polar liquid capacitor increases spontaneously. The two polarized electric fields each form two dipole layer capacitors, and the two dipole layer capacitors are in a parallel relationship.

5. The polar liquid capacitor with spontaneous rapid increase in relative permittivity according to claim 1, characterized in that The polar liquid is any one of water, ethanol and glycerol.

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