CN111200376B

CN111200376B - Friction nano generator

Info

Publication number: CN111200376B
Application number: CN201811507401.0A
Authority: CN
Inventors: 温荣梅; 翟俊宜
Original assignee: Beijing Institute of Nanoenergy and Nanosystems
Current assignee: Beijing Institute of Nanoenergy and Nanosystems
Priority date: 2018-11-19
Filing date: 2018-12-10
Publication date: 2023-05-30
Anticipated expiration: 2038-12-10
Also published as: CN111200376A

Abstract

The invention provides a friction nano generator. The friction layer of the friction nano generator is formed by a nano composite film, wherein the nano composite film is formed by compounding a high molecular polymer and a metal organic framework. The nanocomposite film is used as a friction layer of the friction nano generator, and the output performance of the friction nano generator is improved along with the increase of humidity, so that the friction nano generator is particularly suitable for being applied in a high-humidity environment, and the practical application range of the friction nano generator is greatly widened.

Description

Friction nano generator

Technical Field

The invention relates to the field of generators, in particular to a friction nano generator.

Background

Energy sustainable environmentally friendly collection from nature has attracted considerable attention due to environmental issues such as global energy crisis and global warming. In the energy harvesting technology, friction nano-generators (Trioboelectric Nanogenerators, TENG) have proven to be an economical and simple technology that can directly convert mechanical energy such as wind flow, sea waves and human motion into electrical energy. However, TENG has significantly limited its large-scale commercial application due to its low output performance.

Recently, various methods for solving this problem have been reported successively, for example, selecting a friction material rationally, injecting a charge, controlling morphology, optimizing structure, and the like, among which a method of increasing the charge density of a surface by selecting a friction material rationally is the most effective method of improving the output performance of TENG. Current friction materials are generally limited to some conventional materials of the triboelectric series, but these materials are in turn subject to environmental factors (composition of gas, humidity) which affect the performance of TENG, in particular the effect of humidity on the performance of TENG is great, the humidity increases, a water layer forms on the friction material surface, causing charge transfer or dissipation, eventually leading to a decrease in the output performance of TENG. Therefore, from a material perspective, it remains a challenging task to design new friction materials such that TENG has excellent output performance in different environments.

Disclosure of Invention

First, the technical problem to be solved

The invention provides a friction nano generator for solving at least part of the technical problems.

(II) technical scheme

In one aspect, the invention provides a friction nano-generator, wherein a friction layer of the friction nano-generator is formed by a nano-composite film.

Optionally, the nanocomposite film is formed by compounding a high molecular polymer and a metal organic framework.

Optionally, the high molecular polymer is at least one of polyvinylidene fluoride, polydimethylsiloxane, polytetrafluoroethylene or polyvinyl chloride, and the metal organic framework is at least one of UiO-66, HKUST-1, ZIF-8 or MIL-101.

Optionally, uiO-66 is prepared by taking zirconium chloride as a metal salt and terephthalic acid as an organic ligand, HKUST-1 is prepared by taking copper nitrate as a metal salt and trimesic acid as an organic ligand, ZIF-8 is prepared by taking zinc nitrate as a metal salt and 2-methylimidazole as an organic ligand, and MIL-101 is prepared by taking chromium nitrate as a metal salt and terephthalic acid as an organic ligand.

Alternatively, the nanocomposite film is compounded from polydimethylsiloxane 8 and HKUST-1 9.

Optionally, the HKUST-19 accounts for 1-10wt% of the nano composite film.

Alternatively, the friction nano-generator is of the vertical contact-separation type, sliding type, single electrode type and independent friction type.

Optionally, the friction nano-generator is a vertical contact-separation type comprising: an upper electrode 2; a positive friction layer 3 formed on the surface of the upper electrode 2; a lower electrode 5; the negative friction layer 4 is formed on the surface of the lower electrode 5, and the negative friction layer 4 is formed by a nano composite film; the upper electrode 2 and the lower electrode 5 are connected through an external circuit 7, and the positive friction layer 3 and the negative friction layer 4 are positioned opposite to each other and can be contacted and separated from each other.

Optionally, the friction nano generator further comprises: an upper substrate 1; an upper electrode 2 formed on the surface of the upper substrate 1; and/or, further comprising a lower substrate 6, the lower electrode 5 being formed on a surface of the lower substrate 6.

Alternatively, the nanocomposite film comprises a friction layer having a thickness in the range of 100 microns to 500 microns.

(III) beneficial effects

The invention provides a friction nano generator, wherein a friction layer of the friction nano generator is made of a nano composite film. The nano composite film is formed by compounding a high polymer and a metal organic framework, and is used as a friction layer of the friction nano generator, so that the friction nano generator is separated from the limitation of humidity in the external environment, the output performance of the friction nano generator is improved along with the increase of the humidity, the friction nano generator is particularly suitable for being applied in a high humidity environment, and the practical application range of the friction nano generator is greatly widened.

Drawings

Fig. 1 schematically shows a schematic structural diagram of a friction nano-generator according to an embodiment of the present invention.

FIG. 2 schematically shows a schematic structural diagram of a PDMS+HKUST-1 based friction nano-generator according to an embodiment of the present invention.

FIGS. 3a-c schematically illustrate short circuit currents (I) of embodiments of the invention, respectively _SC ) Open circuit voltage (V) _OC ) And a schematic representation of the change in transferred charge (Q) over time.

FIG. 4 is a graph schematically showing decay time as a function of HKUST-1 content for an embodiment of the invention.

FIG. 5 schematically shows surface topography of nanocomposite films corresponding to different HKUST-1 content in an embodiment of the invention.

FIG. 6 is a graph schematically showing the dielectric constant as a function of HKUST-1 content for an embodiment of the invention.

FIG. 7 schematically shows graphs of TENG output signals based on PDMS/HKUST-1 nanocomposite films under various relative humidity conditions for embodiments of the present invention.

FIG. 8 schematically shows a graph of charge decay time versus relative humidity for a PDMS/HKUST-1 nanocomposite film based TENG according to an embodiment of the present invention.

FIG. 9 schematically shows a graph of dielectric constant versus relative humidity for PDMS/HKUST-1 based nanocomposite films according to embodiments of the present invention.

[ reference numerals ]

1-upper substrate

2-upper electrode

3-Positive Friction layer

4-negative friction layer

5-bottom electrode

6-lower substrate

7-external circuit

8-Polydimethylsiloxane (PDMS)

9-HKUST-1

Detailed Description

The present invention will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent.

TENG is a nano-generator based on triboelectrification and electrostatic inductive coupling, and the basic principle is as follows: when external force is applied, the two friction materials rub against each other, charge transfer occurs, and friction charges are generated; after the deformation force is released, the two surfaces are automatically separated, and the charges on the two surfaces cannot be completely neutralized due to an air layer interposed between the two surfaces, so that a potential difference is formed; to balance this potential difference, opposite charges are induced on the electrode plates, and an external circuit will form an instantaneous current; when external force is applied again, the potential generated by friction charges is continuously reduced, the induced charges flow in opposite directions through an external circuit until the two friction materials are contacted again, and the current returns to zero; the mechanical deformation is thus periodically applied, so that an alternating current signal is continuously generated.

TENG includes 4 modes of operation: vertical contact-separation, sliding, single electrode, and independent friction layers. The vertical contact-separation type friction nano generator working mode is firstly proposed, the mode is that the friction nano generator working mode continuously generates electricity through contact and separation between two friction layers in the vertical direction, when two friction layers with different friction electric sequences are in mechanical contact, opposite charges are generated on the surface of a material, the friction layers which are easy to lose electrons are positively charged, the friction layers which are easy to obtain electrons are negatively charged, when the two friction layers are separated, potential differences are generated between the corresponding electrodes, an external circuit which is connected between the two electrodes is connected with a resistor, free electrons flow from one electrode to the other electrode to balance electrostatic fields, when the distance between the two electrodes is gradually reduced, the potential generated by the friction charges disappears, the induced electrons flow in the opposite direction, the periodic contact and separation between the two friction layers can lead to alternating current generation between the two electrodes, and in the mode, the electricity generation process depends on the contact and separation between the two contact surfaces, and the output current is alternating current.

The sliding type is based on the coupling of sliding friction electrification and a plane charge separation process under the driving of an external force parallel to the horizontal direction of the friction layer. Under the action of external force, the friction force between the contact surfaces of the two friction layers makes the two friction layers slide relatively to generate dense friction charges. The periodic variation of the contact area between the two friction layer surfaces causes a lateral separation of the charge centers, thereby creating a potential difference that generates a current in the external circuit. The single electrode type friction electrification process is the same as that of the former, only one electrode is contained in the friction electrification process, and the transfer of current is realized by utilizing the potential difference between the electrode and the grounding terminal. The independent friction layer is composed of one independent friction layer and two friction electrodes, and power is generated by the reciprocating motion of the independent friction layer between the two friction electrodes.

At present, the most effective method for improving the output performance of TENG is to reasonably select a friction material for a friction layer for friction electrification, wherein a traditional friction material generally adopts a single polymer matrix, and nano particles are embedded in the polymer matrix, so that the electrification performance of the material surface can be changed, the dielectric performance of the material can be changed, and the electrostatic induction process of a friction nano generator is influenced. Metal Organic Frameworks (MOFs) are a class of crystalline materials that link inorganic metal ions (node components) and multiple organic ligands (structural linkers) by coordination chemistry, with the ability to capture electrons, and can be used as nanoparticles embedded in polymeric matrices.

Based on the above thought, the embodiment of the invention provides a preparation method of a nano composite film, wherein the composite film is formed by compounding a high polymer and MOFs according to a certain proportion. The specific method comprises the following steps:

s1, uniformly mixing a high polymer monomer and a curing agent according to a certain proportion (mass ratio of 10:1), adding MOFs into the mixture, and fully stirring to uniformly mix the mixture.

S2, putting the uniformly mixed mixture into vacuum drying property to remove bubbles.

S3, pouring the mixture on a rotating plane (quartz glass) for spin coating (spin coating at a rotating speed of 500rpm for 50S), transferring the quartz glass into an oven (120 ℃) for heating (heating time is determined according to specific conditions, heating for 15min in the embodiment), obtaining a completely cured nano composite film, and stripping the film from the rotating plane.

Wherein the high polymer is at least one of polyvinylidene fluoride (PVDF), polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE) or polyvinyl chloride (PVC), and the metal organic framework is at least one of UiO-66, HKUST-1, ZIF-8 or MIL-101. MOFs is a porous inorganic-organic hybrid material formed by interconnecting metal salts and organic ligands through coordination bonds, uiO-66 is prepared by taking zirconium chloride as a metal salt and terephthalic acid as an organic ligand, HKUST-1 is prepared by taking copper nitrate as a metal salt and trimesic acid as an organic ligand, ZIF-8 is prepared by taking zinc nitrate as a metal salt and 2-methylimidazole as an organic ligand, and MIL-101 is prepared by taking chromium nitrate as a metal salt and terephthalic acid as an organic ligand.

An embodiment of the present invention proposes a friction nano-generator, whose structure is shown in fig. 1, comprising: an upper substrate 1 and a lower substrate 6, both of which are composed of acrylic plates; an upper electrode 2 formed on the surface of the upper substrate 1, the upper electrode 2 being made of gold or copper or silver; a positive friction layer 3 formed on the surface of the upper electrode 2; a lower electrode 5 formed on the surface of the lower substrate 6, the lower electrode 5 also being made of gold or copper or silver; a negative friction layer 4 formed on the surface of the lower electrode 5 and composed of the aforementioned nanocomposite film for generating electric charges by mutual friction with the positive friction layer 3, so that the output performance of the friction nano-generator increases with an increase in humidity; the upper electrode 2 and the lower electrode 5 are connected by an external circuit 7, and the positive friction layer 3 and the negative friction layer 4 are positioned opposite to each other.

The thickness of the friction layer formed of the nanocomposite film may range from 100 micrometers to 500 micrometers.

The positive friction layer 3 may be made of polyamide (nylon) -11, polyamide (nylon) -66, melamine, or the same material as the upper electrode 2, specifically determined according to the friction type of friction nano-power generation, which is not limited by the present invention. The friction category again includes 2 categories of dielectric-dielectric materials and conductive-dielectric materials, for TENG of conductive-dielectric materials, the conductive layer acts as both a friction layer and an electrode.

Wherein the high polymer composing the nano composite film is at least one of polyvinylidene fluoride (PVDF), polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE) or polyvinyl chloride (PVC), MOFs is at least one of UiO-66, HKUST-1, ZIF-8 or MIL-101, the compounding mode of the high polymer and the MOFs is simple physical mixing, or the high polymer-MOFs-high polymer lamellar structure.

Wherein, in the nanocomposite film, the mass of MOFs accounts for 1-20wt% of the mass of the nanocomposite film (the total mass of the high molecular polymer and the MOFs), the size of the MOFs is distributed in a circle with a diameter of 10-1000nm, and the thickness of the nanocomposite film is about 100-500 μm.

The area of the nano composite film is 1cm multiplied by 2cm or 2cm multiplied by 2cm or 2.5cm multiplied by 2.5cm or 3cm multiplied by 3cm, the specific area is determined according to the actual requirement, the invention is not limited, the area is too large or too small, and the practical operation is difficult.

When the nanocomposite film is formed by compounding polydimethylsiloxane 8 and HKUST-19, the structure of the friction nano-generator is shown in figure 2, at the moment, the copper foil simultaneously plays the roles of the upper electrode 2 and the positive friction layer 3, the upper electrode 2 and the positive friction layer 3 are combined into one layer, preferably, in the nanocomposite film, when the mass of HKUST-19 accounts for 4.5wt% -5.5wt% of the total mass of the nanocomposite film, the output performance of friction nano-generator is excellent, most preferably, the mass of HKUST-19 accounts for 5wt% of the total mass of the nanocomposite film, and the output performance of friction nano-generator is optimal. HKUST-19 is an octahedral structure with a size distribution within a circle with a diameter of 50 nm-500 nm.

The TENG taking the nano composite film compounded by the high polymer and MOFs as the negative friction layer has obviously improved output performance, particularly limited humidity, and the output performance of the TENG is improved along with the increase of the humidity, so that the practical application range of the TENG is greatly widened.

In order to more clearly illustrate the invention, the embodiment of the invention tests the influence of different contents of HKUST-19 on TENG output performance when the nano composite film based on polydimethylsiloxane 8/HKUST-1 9 is used as a negative friction layer, analyzes specific reasons and selects nano composite films with the contents of HKUST-19 of 0wt%, 1wt%, 3wt%, 5wt%, 7wt% and 9wt% as test objects.

Figures 3a-c show the short-circuit current (I _SC ) Open circuit voltage (V) _OC ) And the change of the transferred charge (Q) with time, it is obvious from the figure that the content of HKUST-19 is changed, I _SC ，V _OC And Q has a similar trend over time, and the resulting output signal peaks in intensity (37 μA,205V and 48 nC) when the content of HKUST-1 is increased to 5wt%, which are 4.6,3.4 and 3.69 times the TENG output signal (8 μA,60V and 13 nC) based on pure polydimethylsiloxane 8, respectively. As the content of HKUST-19 increases further from 5wt% to 9wt%, the strength of the generated output signal begins to decay, with the output signal increasing and decreasing as the content of HKUST-19 increases. The amount of transferred charge is an important parameter for TENG output performance,which is related to the amount of charge rubbed and the dielectric constant of the negative friction layer material. The reason for this variation will be specifically explained below

First, consider the effect of triboelectric charge on transferred electric charge. Triboelectrification can be further divided into three sub-processes: generation of triboelectric charges, storage of triboelectric charges and electrostatic induction. In fact, electrons trapped by the negative friction layer from the positive friction layer cannot stay on the surface of the negative friction layer, and when electrons accumulate on the contact surface of the two friction layers, since the bottom electrode accumulates positive charges, a built-in electric field will be established between the contact surface and the bottom electrode, and the direction of the electric field is vertically upward, thus two electron transfer modes are generated, namely, a drift process caused by the electric field and a diffusion process caused by the concentration gradient of electrons. Both transitions may result in loss of tribo-electrons due to recombination with positive charges induced on the electrode. In addition, the loss of surface triboelectrons may also recombine with the adsorption of positively charged ions or particles in air. The reduction in the triboelectric charge density eventually leads to deterioration in the output performance of TENG. When the electron-trapping material HKUST-19 is incorporated into the polydimethylsiloxane 8, surface tribo electrons can be effectively trapped inside the negative friction layer and recombination between electrons and positive charges in the air is suppressed due to its high electron trapping property, and thus, a higher tribo charge density of TENG is achieved, so that the transferred charge amount increases.

To verify the capture electronic properties of HKUST-19, the charge decay times of TENGs corresponding to different levels of HKUST-19 were tested accordingly at relative humidity rh=10%, as shown in fig. 4. Decay time is used to characterize the electron storage capacity of different materials, representing the time required for 1/e charge retention. As the HKUST-19 content increased to 5wt%, the TENG decay time gradually increased from 130 minutes (pure polydimethylsiloxane 8) to 500 minutes. This phenomenon suggests that more triboelectric charge is trapped in deeper regions of the dielectric layer. However, as the HKUST-19 content was further increased from 5wt% to 9wt%, the required decay time was reduced to 310 minutes, which may be attributed to the reduced surface area (S) of polydimethylsiloxane 8 and the increased content of HKUST-1 9. To verify this hypothesis, tests were performed on nanocomposite film surface morphologies with varying levels of HKUST-19, as shown in fig. 5, it is evident that the effective friction area of the negative friction layer decreases with increasing levels of HKUST-19, because as the levels of HKUST-19 increase, excess HKUST-19 appears on the surface, the polydimethylsiloxane 8 area on the top surface of the negative friction layer decreases resulting in little triboelectric charge, and the HKUST-19 area on the bottom surface of the negative friction layer increases resulting in loss of triboelectrons (recombination of positive charges and trapped charges induced on the electrode), indicating that this hypothesis is correct.

Second, consider the effect of the dielectric constant of the negative friction layer material on the transferred charge. To analyze the effect of dielectric constant on transferred charge (TENG output performance), the frequency range was 10 at relative humidity rh=10% ² ～10 ⁶ The dielectric constant was measured as a function of HKUST-19 content at Hz, as shown in FIG. 6. It can be seen from the graph that the dielectric constant of the nanocomposite increases monotonically. From the previously reported formulas, the higher the dielectric constant, the greater the transferred charge density.

Thus, under the combined action of the triboelectric charge density and the dielectric constant, when the content of HKUST-19 is increased from 0wt% to 5wt%, the output performance of TENG gradually increases, and the content of HKUST-19 continues to increase, and the output performance of TENG starts. Preferably, in the nanocomposite film, the friction nano-generator has excellent output performance when the mass of HKUST-19 accounts for 4.5 to 5.5 weight percent of the total mass of the nanocomposite film, most preferably, the friction nano-generator has excellent output performance when the mass of HKUST-19 accounts for 5 weight percent of the total mass of the nanocomposite film, and the optimal mass ratio (5 weight percent) is the competitive balance of the influences on TENG output characteristics.

TENG is based on the coupling of triboelectric effect and electrostatic induction, and its performance is closely related to humidity and surface adsorption layer. Previous studies demonstrated that TENG output performance generally decreases significantly with increasing Relative Humidity (RH) in the atmosphere due to the formation of a water skin layer on the triboelectric surface. Here we also studied the effect of water vapor on TENG output performance to further elucidate the practical applicability of the device.

FIG. 7 schematically shows graphs of TENG output signals based on polydimethylsiloxane 8/HKUST-1 9 nanocomposite films under various relative humidity conditions. As shown in fig. 7, it can be seen that the TENG output signal based on pure polydimethylsiloxane 8 decreases with increasing relative humidity, similar to that of conventional TENG. However, the output signal of TENG based on 5wt% hkust-19 shows the opposite trend. It is well known that this phenomenon is unprecedented and that TENG's output performance increases with increasing relative humidity. Clearly, when RH increases to 70%, the electrical output current of TENG based on pure polydimethylsiloxane 8 begins to decrease significantly. When rh=90%, TENG output signal based on pure polydimethylsiloxane 8 drops to 0.6 μa, with initial output losses as high as 90% compared to rh=10%. In contrast, when RH increases from 10% to 90%, the output current of TENG based on 5wt% HKUST-19 increases from 37 μA to 54.5 μA (i.e., the initial value increases by about 140%). This result indicates that HKUST-19 can improve the performance of the generator even in a wet environment. When the content of HKUST-19 was 3wt%, the output properties of TENG remained almost unchanged. As for TENG doped at 1wt%,7wt%,9wt%, although the output signal also decreases with increasing RH, the magnitude of the decrease is still less than that of TENG without HKUST-1 9.

The water adsorbed on the rubbed surface layer plays an important role in the rubbed charge. The effect on TENG output performance on humidity is attributed to: the dissipation of charge results from the formation of a water layer on the surface of the negative friction layer. Table 1 shows the contact angles of nanocomposite films with different HKUST-19 contents.

TABLE 1

As shown in Table 1, it can be seen from the table that when the HKUST-19 content was increased from 0wt% to 9wt%, the contact angle was changed from 105℃to 110℃and the hydrophobicity of the nanocomposite film was not significantly changed, which means that the hydrophobicity was no longer a major factor in evaluating the humidity-dependent output performance of TENG. According to previous reports, HKUST-19 can establish adsorption-desorption equilibrium under a certain humidity environment. As RH increases, more water molecules are absorbed in the pores of HKUST-19 and vice versa. The structural change is accompanied by a distinct transition in nanocomposite color, from deep blue to light blue. As discussed above, the output performance of TENG increases with increasing relative humidity. This phenomenon is attributed to an increase in electron capturing ability and dielectric constant and an increase in relative humidity. When the content of HKUST-19 is 0wt% (pure polydimethylsiloxane 8), the more water molecules are absorbed by the surface of the nanocomposite film, the more surface friction charges are consumed under high humidity conditions, and thus, the output performance of TENG based on pure polydimethylsiloxane 8 decreases with an increase in RH, and in the case of TENG based on nanocomposite film incorporating HKUST-19, HKUST-19 can effectively trap surface friction electrons inside the friction layer.

Fig. 8 schematically shows the charge decay time of TENG as a function of relative humidity. As shown in fig. 8, it can be seen from the graph that the decay time of TENG based on pure polydimethylsiloxane 8 decreases with increasing relative humidity. When RH increases from 10% to 90%, decay time decreases from 130 minutes to 25 minutes. However, the decay time of TENG based on 5wt% hkust-19 shows the opposite trend. It increases from 500 minutes to 1200 minutes (i.e., 240% of the initial value), indicating that when RH increases from 10% to 90%, the average number of increased internal electrons is greater than the number of reduced surface electrons, consistent with the output performance described above. When the content of HKUST-19 is further increased from 5wt% to 9wt%, the required decay time decreases with RH, which may be an excessively strong electron capturing ability to absorb water HKUST-1, pushing more of the captured electrons toward the bottom of the dielectric layer, resulting in a loss of tribo electrons due to recombination with positive charges induced on the electrode. The dependence of decay time on RH is similar to the output performance of TENG devices.

Fig. 9 schematically shows the dielectric constant of the nanocomposite film as a function of relative humidity. As shown in fig. 9, for pure polydimethylsiloxane 8, the dielectric constant is not affected by relative humidity; the dielectric constant of the nanocomposite film comprising HKUST-19 increased monotonically with increasing RH due to the increasing dielectric constant of HKUST-19 with increasing RH. For a nanocomposite film with a HKUST-19 content of 5wt%, when RH is increased from 10% to 90%, the dielectric constant is increased from 3.0 to 3.4 (i.e., 113% of the initial value) at a frequency of 1000 Hz. As RH increases, the electron capturing ability and dielectric constant of HKUST-19 are improved by the water molecules in the three-dimensional pore absorption, resulting in an enhancement of the output performance of TENG. Therefore, triboelectric charge and dielectric properties play a more important role than hydrophobicity in affecting TENG output performance.

In summary, in the embodiment of the invention, the nanocomposite film formed by compositing the high polymer and the metal organic framework is used as the negative friction layer of the friction nano-generator, and due to the introduction of the metal organic framework, even if the environmental humidity is increased, the friction charge density is increased, and the dielectric constant of the negative friction layer is increased, so that the density of transferred charges is increased, the output performance of the friction nano-generator is increased along with the increase of the humidity, the application range of the friction nano-generator is greatly widened, and the large-scale commercial application of the friction nano-generator is facilitated.

While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be had by the present invention, it should be understood that the foregoing description is merely illustrative of the present invention and that no limitations are intended to the scope of the invention, except insofar as modifications, equivalents, improvements or modifications are within the spirit and principles of the invention.

Claims

1. The friction nano generator is characterized in that a friction layer of the friction nano generator is formed by a nano composite film;

wherein, the nano composite film is formed by compounding a high molecular polymer and a metal organic framework.

2. The friction nano-generator according to claim 1, wherein the high molecular polymer is at least one of polyvinylidene fluoride, polydimethylsiloxane, polytetrafluoroethylene or polyvinyl chloride, and the metal-organic framework is at least one of uo-66, HKUST-1, ZIF-8 or MILs-101.

3. The friction nano generator according to claim 2, wherein said UiO-66 is prepared by using zirconium chloride as a metal salt and terephthalic acid as an organic ligand, said HKUST-1 is prepared by using copper nitrate as a metal salt and trimesic acid as an organic ligand, said ZIF-8 is prepared by using zinc nitrate as a metal salt and 2-methylimidazole as an organic ligand, and said MIL-101 is prepared by using chromium nitrate as a metal salt and terephthalic acid as an organic ligand.

4. The friction nano-generator according to claim 1, wherein the nano-composite film is compounded by polydimethylsiloxane (8) and HKUST-1 (9).

5. The friction nano generator according to claim 4, wherein the mass of HKUST-1 (9) is 1wt% to 10wt% of the mass of the nano composite film.

6. The friction nano generator according to any one of claims 1-5, wherein the friction nano generator is of a vertical contact-separation type, a sliding type, a single electrode type and an independent friction layer type.

7. The friction nano-generator of claim 6, wherein the friction nano-generator is a vertical contact-separation type comprising:

an upper electrode (2);

a positive friction layer (3) formed on the surface of the upper electrode (2);

a lower electrode (5);

a negative friction layer (4) formed on the surface of the lower electrode (5), the negative friction layer (4) being composed of the nanocomposite film;

the upper electrode (2) and the lower electrode (5) are connected through an external circuit (7), and the positive friction layer (3) and the negative friction layer (4) are opposite in position and can be contacted and separated from each other.

8. The friction nano-generator of claim 7, wherein the friction nano-generator further comprises:

an upper substrate (1); the upper electrode (2) is formed on the surface of the upper substrate (1);

and/or, further comprising a lower substrate (6), the lower electrode (5) being formed on the surface of the lower substrate (6).

9. The friction nano-generator according to claim 8, wherein the thickness of the friction layer formed of the nano-composite film ranges from 100 micrometers to 500 micrometers.