CN115549515A - Preparation method and application of conductor friction nano generator - Google Patents

Abstract

The invention discloses a preparation method and application of a conductor-based friction nano generator, belongs to the technical field of nano energy, and is used for energy collection. The invention uses two different conductors as friction layer material and electrode; the conductors constituting the vertical contact mode rub the nanogenerator in a face-to-face manner. PSS as a typical fabricated tribo-nanogenerator, which can achieve an open circuit voltage of 1400V and 1333mA m due to the density of states matching between the triboelectric layers of the two conductors ^‑2 The ultra-high current density of (2). The current density is increased by nearly three orders of magnitude compared to conventional dielectric TENGs. More importantly, the apparatus of the present invention can operate stably in high humidity environments, which has been a significant challenge for conventional TENGs. The TENG of the present invention may even perform well with water droplets in the triboelectric layer.

Description

Preparation method and application of conductor friction nano generator

Technical Field

The invention relates to a nano energy source, in particular to a preparation method and application of a conductor friction nano generator.

Background

The friction nano-generators (TENGs) can effectively convert discrete low-frequency mechanical energy into electric energy by utilizing the triboelectric effect and electrostatic induction. The triboelectric layer in TENGs is typically composed of dielectric polymers with different electron affinities. In some cases, metals with electron loss capability may also be used as the positive friction layer. High output voltages (kV) are commonly achieved in many TENGs; however, the output current is typically low (typically in the μ a range). The low output current limits many practical applications of TENGsIn particular in terms of energy harvesting. Theoretically, it is critical to improve the output current to improve the charge transfer between the triboelectric layers or to shorten the charge transfer time. Many sophisticated TENGs have developed high output currents. For example, wang et al reported that 300mA m was reached in vacuum by avoiding dielectric breakdown ^-2 High current density. Wu et al combine TENG with quasi-transistor circuit to realize 1000mA m ^-2 High current density. Although the above strategies may increase the output current of TENGs, the resulting output current is still not high enough due to the complex device structure. It is important to further improve the output current of TENGs, especially TENGs of simple structure.

In addition, the output performance of TENGs is typically affected by humidity. Generally, in a high humidity environment, the triboelectric effect is greatly hindered due to charge leakage from the triboelectric meter to the air. Thus, the advantageous performance of TENGs is significantly reduced in high humidity environments. Increasing the humidity resistance of TENG has been a hot spot of research. In some reports, triboelectric layers are made hydrophobic by material selection or surface engineering to improve the stability of TENGs in high humidity air. The stability of TENG in high humidity environments is also improved by the electrostatic breakdown effect. However, designing high performance TENGs that can operate in high humidity environments remains a significant challenge.

In this case, we have designed and manufactured a new type of TENG with conductive materials as the triboelectric layer and the electrodes. This new TENG is simple in structure, and its output performance, particularly current density, is the highest among TENGs in the contact separation mode due to state density matching (DOS). More interestingly, the output performance of C-TENG showed excellent endurance under high humidity conditions. The C-TENG still performs well when water droplets are present on the triboelectric layer.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a preparation method and application of a conductor friction nano generator which has excellent stability in a high-humidity environment, high output current and stable operation in the high-humidity environment.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: a preparation method of a conductor-based triboelectric nano-generator uses different conductors as friction layer materials and electrodes; the manufactured conductor friction nano-generator C-TENG uses copper and PEDOT: PSS (a conductive polymer material) or aluminum and PEDOT: PSS as a positive electrode friction material and an electrode and a negative electrode friction material and an electrode, and forms a vertical contact mode conductor friction nano-generator in a face-to-face mode, so that a large current signal is obtained.

Preferably, the size of the friction layer of the specific friction nano generator is 5 multiplied by 5cm ² The pressure was 5N, the frequency was 5Hz, and the spacing was 6mm.

Preferably, the generator can obtain an open-circuit voltage of 1400V and 1333mA m ^-2 Compared to conventional dielectric TENGs, the current density of the ultra-high current density of (a) is increased by nearly three orders of magnitude.

Preferably, copper is used as the positive friction material and electrode, and PEDOT: PSS is used as the negative friction material and electrode.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: C-TENG can be used for energy conversion and driving electrical equipment.

Preferably, the C-TENG is used as an energy harvester to harvest energy from a variety of mechanical movements.

Preferably, the calculator watch is powered using C-TENG, so that it can work properly.

Preferably, the low power electronics are driven by connecting the C-TENG to a commercial bridge rectifier and capacitor.

Has the advantages that:

the invention uses two different conductors as friction layer material and electrode; the conductors constituting the vertical contact mode rub the nanogenerator in a face-to-face manner. PSS as a typical fabricated tribo nanogenerator, which can achieve an open circuit voltage of 1400V and 1333mA m due to the density of states matching between the triboelectric layers of the two conductors ^-2 The ultra-high current density of (2). The current density is increased by a factor of two compared to conventional dielectric TENGsThree orders of magnitude. More importantly, our apparatus can operate stably in high humidity environments, which has been a significant challenge for conventional TENGs. Surprisingly, our TENG can even perform very good electrical properties when water droplets are contained in the triboelectric layer. This work provides a new and effective strategy for building high performance TENGs that will be available for many practical applications in the near future.

The novel TENG has a simple structure, and the output performance, particularly the current density of the novel TENG is the highest in the TENG in a contact separation mode. We further analyzed the reason for the superior performance by density of states matching (DOS). More importantly, the C-TENG has excellent stability in high humidity environments. The C-TENG still performs well when water droplets are present on the triboelectric layer. The invention provides a promising method for preparing a TENG device with high output current and stable high humidity environment.

Drawings

FIG. 1 shows the design concept and output performance of C-TENG. (a) The density of states between the three triboelectric pairs are matched, namely medium-medium, conductor-medium and conductor-conductor; (b) Surface potentials of Al, paper, cu, PEDOT PSS, PET, PI, PDMS, and PTFE; based on various triboelectric pairs of TENGs (size =3 × 3 cm) ² ) Outputting (c) the voltage and (d) the current; (e) Comparison with the TENG current density for the vertical contact separation mode reported previously.

FIG. 2 is a graph of the effect of (a) size, (b) pressure, (C) frequency, (d) spacing on the electrical performance of C-TENG.

FIG. 3 shows the stability and humidity resistance of C-TENG. (a) The current of C-TENG was essentially constant at 10000 cycles of operation at 30% Relative Humidity (RH). (b) C-TENG maintained high stability for one week at 30% RH. (c) photograph of glove box with humidity control. (d) The voltage and current of conventional dielectric materials drop sharply when the RH is 10% -100%. (e) The voltage current of C-TENG remains stable when RH is in the range of 10% -100%.

FIG. 4 is a graph of the electrical performance stability of C-TENG and conventional dielectric TENG affected by water droplets. (a-b) schematic of C-TENG and dielectric TENG affected by water droplets. (C-d) output voltage and current of C-TENG in dry and wet states. (e-f) output voltage and current of the dielectric TENG in dry and wet states. (g-h) suppression of charge leakage in dielectric TENG and charge leakage in C-TENG.

FIG. 5C-TENG application as an energy source. (a) The output voltage and current of C-TENG at different external load resistances. The working frequency is controlled at 5Hz, and the external force is controlled at 5N. (b) Power densities of C-TENG and dielectric TENG at different external load resistances. (C-d) Using C-TENG at 5X 5cm ² About 750 LEDs are powered at small size. (e) The C-TENG is the voltage response curve for the capacitor at 1, 4.4, 10, 100 and 470 μ F charge. (f) driving photographs of commercial calculators using C-TENG.

Detailed Description

The invention is described in detail below with reference to the figures and the embodiments.

Example 1

When the two friction layers are in contact, electrons in the material with the higher fermi level will be transferred to the material with the lower fermi level until the new fermi levels of the two materials become the same. When the triboelectric layer is composed of a dielectric material, a small change in surface charge density can result in a large change in the fermi level at the forbidden band. In contrast, the variation of the fermi level of conductors is much less sensitive to surface charge density because their state Density (DOS) is generally higher near the fermi level (fig. 1 a). Thus, when using two dielectric materials as a triboelectric pair, the amount of charge transfer is typically small, as a small amount of charge transfer can balance their fermi levels. Therefore, the corresponding TENG output current is low. For TENG, which is a combination of a dielectric material and a conductive material, the output current is still low because, although the conductive material can provide many electrons, the dielectric material cannot accept many electrons. In sharp contrast, when two conductive materials are used to make a TENG, many electrons need to be transferred to balance their fermi levels due to the higher DOS of both materials near the fermi level. Therefore, a very high output current is expected. Note that electrostatic induction is negligible in TENG consisting of two conductive triboelectric layers.

FIG. 1 shows the design concept and output performance of C-TENG. (a) The density of states of the three triboelectric pairs are matched, namely medium-medium, conductor-medium and conductor-conductor. (b) Surface potentials of Al, paper, cu, PEDOT PSS, PET, PI, PDMS, and PTFE. Based on various triboelectric pairs of TENGs (size =3 × 3 cm) ² ) Outputting (c) the voltage and (d) the current. (e) Comparison with the TENG current density for the vertical contact separation mode reported previously.

We use three types of triboelectric pairs, namely dielectric-dielectric, conductive-dielectric and conductor-conductor. First, we measured the surface potential of a commonly used triboelectric material, which is strongly related to electron affinity (fig. 1 b). Then, dielectric materials with different surface potentials are selected as a triboelectric pair, and the output performance of the triboelectric pair is tested. The highest open circuit voltage (V) of the Polyimide (PI)/Polydimethylsiloxane (PDMS), polyethylene terephthalate (PET)/Polytetrafluoroethylene (PTFE) and paper/PTFE pairs _OC ) 312V, the highest short-circuit current (I) _SC ) At 2.8. Mu.A (FIGS. 1 c-d). Next, we measured the output properties of TENGs composed of dielectric and conductive materials. For the Cu/PTFE pair, V _OC And I _SC Are slightly lower than the paper/PTFE pair due to the smaller electronegative difference between Cu and PTFE. In sharp contrast, when the triboelectric layer is composed of an electrically conductive material, its output performance, in particular short-circuit current, is significantly improved. The invention adopts copper, aluminum (Al) and poly (3, 4-ethylenedioxythiophene) -poly (styrene sulfonate) (PEDOT: PSS, a conductive polymer) as a triboelectric material.

It is noteworthy that the surface potential difference between Cu and Al, cu and PEDOT: PSS, al and PEDOT: PSS is much smaller than that of the paper/PTFE pair. However, for 3X 3cm ² The output voltage of the TENG of Cu/PEDOT PSS and Al/PEDOT PSS reaches 1000V, the current reaches 1200 mu A, and the current ratio consists of dielectric/dielectric and dielectric/conductor pairsAbout 3 orders of magnitude higher. This value is significantly greater than conventional TENG consisting of dielectric/dielectric and dielectric/conductor. For better comparison with other work, we normalized the short circuit current to obtain a current density of 1333mA m ^-2 . This current density is 55 times higher than the highest current density of TENGs of the other vertical contact modes (fig. 1 e).

Comparative experiment 1: different size (fig. 2)

Size from 1 x 1cm ² Increase to 5 x 5cm ² The voltage increased from 500V to 1400V; the current increased from 900 μ A to 2000 μ A. As the size of the tribolayer increases, the total charge transferred between the two tribolayers increases, and thus the electrical properties increase.

By making 3 sizes long by wide (1 by 1cm) ² ，3*3cm ² ,5*5cm ² ) Voltages are 500V,900V and 1400V respectively; the currents were 900 μ A,1200 μ A,2000 μ A, respectively. As the size increases, the voltage and current increase linearly (fig. 2 a).

Comparative experiment 2: different pressures.

We passed the fabrication of a size of 5 x 5cm ² The pressure applied to the device is increased from 1N to 5N, and the voltage is increased from 500V to 1400V; the current was from 700 muA to 2000 muA, and as the pressure increased, the contact area of the two friction layers (copper foil and PEDOT: PSS) also increased, resulting in increased voltage and current (FIG. 2 b).

Comparative experiment 3: different frequencies.

When the operating frequency was increased from 1Hz to 5Hz, the output voltage stabilized at 1400V and the current linearly increased from 800 μ A to 2000 μ A (FIG. 2 c). An increase in frequency leads to an increase in charge transfer, well accounting for the increase in output current.

Comparative experiment 4: different pitches.

The initial separation distance of the two triboelectric layers also affects the output performance of the C-TENG. When the initial separation distance was about 6mm, the maximum values of voltage and current were 1400V and 2000 μ A, respectively (FIG. 2 e). From the initial separation distance of 2mm to 6mm, the electrostatic induction between the two friction layers is enhanced along with the increase of the distance, so the electrical property is increased, and the output voltage and the current are linearly increased; as the initial separation distance is further increased from 6mm, the electrostatic induction phenomenon is suppressed by the distance between the two friction layers being too far, thereby suppressing charge transfer, resulting in deterioration of electrical properties.

FIG. 2C-optimization of TENG output performance. (a) The voltage and current increase with increasing size of the friction layer. (b) the voltage and current increase with increasing external force. (c) The voltage remains stable and the current increases with increasing operating frequency. (d) As the initial separation distance increases, the voltage and current increase and then decrease, and the optimum voltage and current are obtained at an initial separation distance of 6mm.

FIG. 3 shows the electrical property stability and moisture resistance of C-TENG.

(a) The current of C-TENG was essentially constant at 10000 cycles of operation at 30% Relative Humidity (RH). (b) C-TENG still maintained high stability within one week at 30% RH. (c) photograph of a humidity controlled glove box. (d) The voltage and current of conventional dielectric materials drop sharply when the RH is 10% -100%. (e) The voltage current of C-TENG remains stable when RH is in the range of 10% -100%.

In the following experiments we used copper as positive friction material and electrode and PEDOT: PSS as negative friction material and electrode. Selecting the size of the device to be 5 x 5cm ² The devices of (1) were tested for their stability, as shown in FIG. 3, and our C-TENGs showed very high stability in cycling measurements. The output current remained at the initial value (fig. 3 a) after 10000 cycles of C-TENG operation at ambient conditions and 7 days of operation, indicating that C-TENG has good electrical stability.

Furthermore, we chose 1 x 1cm ² The devices of dimensions were tested for humidity stability. The test result shows that compared with the dielectric material TENG, the electrical property suddenly drops along with the increase of the humidity; and the C-TENG also shows higher stability in a high-humidity environment. When the relative humidity is increased from 10% to 100%, there is little change in voltage and current.

Fig. 4 shows the electrical properties in the case of water droplets on the surface of the friction layer.

In addition to the response to humidity, the effect of water droplets on electrical performance was further explored. FIG. 4 is a graph of the electrical performance stability of C-TENG and conventional dielectric TENG affected by water droplets. (a-b) schematic of C-TENG and dielectric TENG affected by water droplets. (C-d) output voltage and current of C-TENG in dry and wet states. (e-f) output voltage and current of the dielectric TENG in dry and wet states. (g-h) suppression of charge leakage in dielectric TENG and charge leakage in C-TENG.

As shown in fig. 4, the C-TENG still exhibited high performance even in the presence of water droplets between the two rubbing layers. However, water droplets were clearly observed on the Cu and PEDOT: PSS surfaces (FIGS. 4 a-b), and we still observed a voltage and current of 350V and 700 μ A, which were approximately 78% and 83% in the dry state (FIG. 4 d). For comparison, we also performed similar experiments on dielectric TENG. When the triboelectric layer has water droplets present, almost no output voltage and current can be detected in the dielectric (fig. 4 e-f). In humid air, the output performance of TENGs typically drops significantly due to charge leakage from the triboelectric layer into the air (fig. 4 g). However, when both the rubbing layers are highly conductive rubbing electric layers, charge leakage is suppressed. The electron transfer in the conductive triboelectric layer is much easier compared to the leakage of charge from the triboelectric layer to the air (fig. 4 h).

Fig. 5 shows voltage, current and power under different loads.

FIG. 5C-TENG application as an energy source. (a) C-TENG outputs voltage and current at different external load resistances. The working frequency is controlled at 5Hz, and the external force is controlled at 5N. (b) The power density of C-TENG and dielectric TENG at different external load resistances. (c) The C-TENG is the voltage response curve for the capacitor at 1, 4.4, 10, 100 and 470 μ F charge. (d) photographs of commercial calculator driven using C-TENG. (e) C-TENG at 5X 5cm under 30% RH ² Is used to power about 750 LEDs. (f) At 100% RH, using C-TENG at 5X 5cm ² About 600 LEDs are powered at small size.

C-TENG can be used for energy conversion and driving electrical equipment. As shown in FIG. 5a, different load resistances were tested by connecting the C-TENG made by us in series with different resistorsVoltage down, with external resistance from 10 ³ Increased to 10 ⁹ The output voltage of Ω, C-TENG increased from 400V to 1400V and the output current dropped from 2.4mA to 2 μ A (FIG. 5 a). Further, the external load was 100 k.OMEGA., and the maximum power density of the C-TENG was 160 W.m ^-2 Compared to the conventional TENG, the maximum power density is 276 times that of the conventional TENG (fig. 5 b).

Low power electronics are driven by connecting C-TENG to a commercial bridge rectifier and capacitor.

The energy generated by the friction nano-meter power generation is in the form of alternating current, so that the energy in the form of alternating current needs to be converted into direct current through a rectifier to supply power for small-sized electronic equipment, and a circuit diagram is shown in fig. 5 c.

A. The charging ability of capacitors with different capacitances was evaluated using C-TENG to charge them. Commercial capacitors with capacities of 1, 4.4, 10, 100, 470 muf were charged. Under the force of a hand tap, the 10 μ F capacitor can charge up to 5V in 13s, as shown in FIG. 5 c.

B. The use of C-TENG to power the calculator allows it to function properly as shown in fig. 5 d.

This result demonstrates the effectiveness of C-TENG as a means to convert biomechanical energy to electrical energy

As shown in fig. 5, is externally connected with a plurality of LED bulbs.

The C-TENG is used as an energy collector to collect energy from various mechanical movements. As shown in FIG. 5e, the flow rate was determined by simply collecting the flow rate from the tapping (size 5X 5 cm) at 30% RH ² ) And the external 750 LED bulbs are successfully lighted. More critically, C-TENG was used at 5 x 5cm at 100% RH ² About 600 LEDs are powered at small size. The results show that the C-TENG can operate stably in high humidity environments.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalents or equivalent changes fall within the protection scope of the present invention.

Claims (8)

1. A preparation method of a conductor-based triboelectric nano-generator is characterized in that different conductors are used as a friction layer material and an electrode; the manufactured conductor friction nano-generator C-TENG uses copper and PEDOT: PSS (a conductive polymer material) or aluminum and PEDOT: PSS as a positive friction material and an electrode and a negative friction material and an electrode respectively, and forms a conductor friction nano-generator in a vertical contact mode in a face-to-face mode.

2. The method of claim 1, wherein the conductor-based triboelectric nanogenerator comprises: the size of the friction layer of the specific friction nano generator is 5 multiplied by 5cm ² The pressure was 5N, the frequency was 5Hz, and the spacing was 6mm.

3. The method of claim 1, wherein the conductor-based triboelectric nanogenerator comprises: the generator can obtain an open-circuit voltage of 1400V and 1333mAm ^-2 Compared to conventional dielectric TENGs, the current density of the ultra-high current density of (a) is increased by nearly three orders of magnitude.

4. Use of a conductive triboelectric nanogenerator according to claim 1, characterized in that: copper is used as a positive friction material and an electrode, and PEDOT: PSS is used as a negative friction material and an electrode.

5. The application of the triboelectric nano-generator of the conductor prepared by the method of claim 1 is characterized in that: C-TENG can be used for energy conversion and to drive electrical equipment.

6. Use of a conductive triboelectric nanogenerator according to claim 4, characterized in that: the C-TENG is used as an energy harvester to harvest energy from various mechanical movements.

7. Use of a conductive triboelectric nanogenerator according to claim 4, characterized in that: the use of C-TENG to power a calculator watch allows it to work properly.

8. Use of a conductor triboelectric nanogenerator according to claim 4, wherein: low power electronics are driven by connecting C-TENG to a commercial bridge rectifier and capacitor.

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