WO2017045910A1

WO2017045910A1 - Triboelectric generator with regeneration of active surface

Info

Publication number: WO2017045910A1
Application number: PCT/EP2016/070391
Authority: WO
Inventors: Guillaume Lamblin; Damien Lenoble; Kevin MENGUELTI
Original assignee: Luxembourg Institute Of Science And Technology (List)
Priority date: 2015-09-14
Filing date: 2016-08-30
Publication date: 2017-03-23
Also published as: LU92828B1

Abstract

The invention is directed to a triboelectric generator (1) comprising at least one disc-shaped first unit (4, 8) including a substrate (4¹, 8¹) and a layer (4², 8²) of a first material being a dielectric material taken from the triboelectric series; at least one disc-shaped second unit (6) including a second material being a metallic material taken from the triboelectric series; the at least one first unit (4, 8) and the at least one second unit (6) being configured for rotating relative to each other around a rotation axis (10). The generator (1) further comprises auxiliary electrodes configured for contacting the second material at the periphery of the at least one second unit and for transmitting a regenerative current of the surface of said second material contacting the first material.

Description

TRIBOELECTRIC GENERATOR WITH REGENERATION OF ACTIVE SURFACE

Technical field

[0001] The invention is directed to triboelectricity, more particularly to triboelectric generators.

Background art

[0002] In the context of the present invention, triboelectricity is the electricity produced by friction, for example after a contact and/or a rubbing of two triboelectric materials. A triboelectric material is a material that has the property to release or accept electrons when it is in contact and/or rubbed against another triboelectric material. The affinity of a triboelectric material to accept or release electrons is classified in the triboelectric series. A non- exhaustive triboelectric series can be given, by order of affinity of materials to release electron at the beginning of the list to affinity of material to accept electron at the end of the list: Asbestos, Glass, Mica, Nylon, Lead, Silk, Aluminium, Steel, Wood, Lucite, Amber, Hard Rubber, Mylar, Nickel, Copper, Silver, Brass, Synthetic Rubber, Gold, Platinum, Sulphur, Acetate, Rayon, Polyester, Celluloid, Polystyrene, Orion, Acrylic, Polyvinylidene chloride (Saran), Polyurethane, Polyethylene, Polypropylene, Polyvinylchloride (Vinyl), PTFE, Silicon, Teflon, Silicone Rubber. A generator is a device that is producing electricity that can be supplied to a consuming device.

[0003] Prior art patent document published US 2014/0246951 A1 describes the principle and experimental realization of a sliding triboelectric generator. Opposite charges are created on the surfaces of two different dielectric triboelectric materials (selected at two opposite positions in the triboelectric series) when they are put into contact. When a translation sliding movement along one direction is applied to take away the two materials, an electric field is created between the two charged surfaces due to the immobility of the charges at the surface of the dielectric materials. If both the triboelectric materials are covered by a conductive material on the opposite surfaces of the contact surfaces and if those conductive layers are electrically connected by an electrical load, a current is circulating in the load during the sliding movement. When a sliding back movement is applied to recover the initial position of the surfaces, a current of the same intensity but opposite sign is generated. Although the authors used the "nano" prefix on their triboelectric generator, the mentioned size of the device is 71 ^*51 mm. The only nanometric aspect of the device is linked to a nano-texturation of the triboelectric surfaces in contact. That document proposes also a new design to convert mechanical movement into triboelectricity via a radial array of triboelectric sectors. A radially arranged array of metallic sectors (rotator) is rotating in contact with a disk-shaped dielectric material (stator) underneath. Both materials are triboelectric materials taken at two different opposite positions in the triboelectric series. A disk-shaped layer of interdigitated electrodes is placed underneath the above described stack of triboelectric materials. When the sectors are rotating the device is producing induced electricity between the interdigitated electrodes. Such device dimensions are about 130^*130 mm. The way how the two interdigitated electrodes are connected to the external circuit is also not disclosed.

Yannan Xie, Sihong Wang, Simiao Niu, Long Lin, Qingshen Jing, Yuanjie Su, Zhengyun Wu, Zhong Lin Wang, Multi-layered disk triboelectric nanogenerator for harvesting hydropower, Nano Energy, Volume 6, May 2014, Pages 129-136, ISSN 221 1-2855, discloses a multi-layered triboelectric nanogenerator with two rotators made of acrylic substrates coated on both side with metallic triboelectric layers. Each rotator is sandwiched between two stators where one of these two stators is shared with the other rotator. Each of the rotators and the triboelectric layers are structured in eight sectors. The current is to be collected between each pair of stator sandwiching a rotator and the rotator. No indications as to how the connections of the electrode to the external circuit are made are provided. Also, the precise device dimensions are not mentioned but clearly appear to be in cm scale. The sector-shape construction of the stators and rotators is mechanically not quite practical. [0005] Generally speaking, over time, the repeated contacts of the surfaces of the triboelectric materials will progressively damage those surfaces. The triboelectric current will therefore inevitably decrease and even cancel after a certain period of use.

Summary of invention

Technical Problem

[0006] The invention has for technical problem to provide a triboelectric generator that solves at least one problem of the prior art, in particular of the above cited prior art. More particularly, the invention has for technical problem to provide a triboelectric generator that is compact and that has a longer life.

Technical solution

[0007] The invention is directed to a triboelectric generator comprising: at least one disc-shaped first unit including a substrate and a layer, on said substrate, of a first material being a dielectric material taken from the triboelectric series; at least one disc-shaped second unit including a second material being a metallic material taken from the triboelectric series; the at least one first unit and the at least one second unit being configured for rotating relative to each other around a rotation axis, with the first and the second materials rubbing against each other so as to transfer electrons from the second material to the first material and electrically charge said materials; wherein the generator further comprises auxiliary electrodes configured for contacting the second material at the periphery of the at least one second unit and for transmitting a regenerative current of the surface of said second material contacting the first material.

[0008] The at least one first unit and the at least one second unit are advantageously coaxial.

[0009] The electrically charged first and/or second material can be connected to a first and second electrode members for delivering an output voltage.

[0010] The first material is advantageously Polyester, Celluloid, Polystyrene,

Orion, Acrylic, Polyvinylidene chloride (Saran), Polyimide Polyurethane, Polyethylene, Polypropylene, Polyvinylchloride (Vinyl), PTFE, Silicon, and/or Teflon.

[001 1] The second material is advantageously copper or aluminium.

[0012] According to a preferred embodiment, the auxiliary electrodes are positioned at diametrically opposed locations at the periphery of the at least one second unit.

[0013] According to a preferred embodiment, the auxiliary electrodes are movable between a position where they are distant from the second material and a position where they electrically contact said material.

[0014] According to a preferred embodiment, the auxiliary electrodes are movable in a diametrical direction of the at least one second unit.

[0015] According to a preferred embodiment, each of the at least one second unit comprises a peripheral edge surface that is radially outwardly oriented, the second material extending to said peripheral edge surface, so as to be contacted by the auxiliary electrodes.

[0016] According to a preferred embodiment, the auxiliary electrodes extend parallel to the rotation axis or form an angle of less than 30°, preferably less than 15°, with said axis.

[0017] According to a preferred embodiment, the generator further comprises an electric unit configured for applying a regenerative current to the second material through the auxiliary electrodes.

[0018] The regenerative current density can be of at least 10mA cm². The regenerative current signal can be continuous or direct. It can also be alternating.

[0019] According to a preferred embodiment, the at least one second unit extend radially outwardly beyond the at least one first unit, so that the auxiliary electrodes can contact said second unit(s) without contacting said first unit(s).

[0020] According to a preferred embodiment, the at least one first unit comprises a pair of first units for each of the least one second unit, said pair of first units sandwiching said second unit, the substrate of each of said first units comprising first and second electrode members, said first and second electrode members comprising a series of first and second radially extending electrodes legs, respectively, said first and second electrodes legs being disposed in an alternating manner around the rotation axis. The generator can comprise several second units, each of said second unit being sandwiched by a pair of first units. A single first unit can be disposed between each pair of adjacent or successive second units, said first unit being common for said pair of second units. The first material can then be applied on both sides of the substrate.

[0021] According to a preferred embodiment, the first electrode member comprises an outer ring integrally formed with the first electrodes legs, and the second electrode member comprises an inner ring integrally formed with the second electrodes legs, the outer ring comprising a radially outwardly extending portion forming at the periphery of the substrate a connector of the first electrode member, and one of the second electrodes legs extending radially through and out of the outer ring so as to form at the periphery of the substrate a connector of the second electrode member.

[0022] According to a preferred embodiment, the connectors of the first and second electrode members at the periphery of the substrate of each first unit are located within a sector centred on the rotation axis and of less than 30°, preferably less than 20°, more preferably less than 10°.

[0023] According to a preferred embodiment, the connectors of the first electrode member of the first units are aligned, preferably along a direction parallel to the rotation axis, and are electrically connected via a first connecting bar, and/or the connectors of the second electrode member of the first units are aligned, preferably along a direction parallel to the rotation axis, and are electrically connected via a second connecting bar.

[0024] According to a preferred embodiment, the second material of the at least one second unit forms legs that extend radially with areas between adjacent legs that are void of said material.

[0025] According to a preferred embodiment, each of the at least one second unit comprises a substrate with a hub, an outer ring and leg portions radially extending between the hub and the outer ring, said substrate being made of dielectric material and the second material being coated on said substrate.

[0026] According to a preferred embodiment, the generator comprises a rotating axle extending along the rotation axis, said axle being rotatably engaged with the at least one second unit, said axle and second unit(s) preferably comprising mutually engaging toothed profiles.

[0027] The invention is also directed to a method of regeneration of the contact surface(s) of a triboelectric generator, wherein generator is in accordance with the invention and said method comprises a step of applying a regenerative current through the at least one second unit via the auxiliary electrodes while the generator is inoperative.

[0028] According to a preferred embodiment, the step of applying a regenerative current is carried out for different angular positions of the at least one second unit.

[0029] According a first other aspect, the invention is also directed to a triboelectric generator comprising: at least one disc-shaped first unit including a substrate and a layer, on said substrate, of a first material being a dielectric material taken from the triboelectric series; at least one disc-shaped second unit including a second material being a metallic material taken from the triboelectric series; the at least one first unit and the at least one second unit being configured for rotating relative to each other around a rotation axis, with the first and the second materials rubbing against each other so as to transfer electrons from the second material to the first material and electrically charge said materials; wherein the at least one first unit comprises a pair of first units for each of the least one second unit, said pair of first units sandwiching said second unit.

[0030] Advantageously, the substrate of each of said first units comprising first and second electrode members.

[0031] Advantageously, the first and second electrode members comprise a series of first and second radially extending electrodes legs, respectively, said first and second electrodes legs being disposed in an alternating manner around the rotation axis. The generator can comprise several second units, each of said second unit being sandwiched by a pair of first units.

[0032] According a second other aspect, the invention is also directed to a triboelectric generator comprising: at least one disc-shaped first unit including a substrate and a layer, on said substrate, of a first material being a dielectric material taken from the triboelectric series; at least one disc-shaped second unit including a second material being a metallic material taken from the triboelectric series; the at least one first unit and the at least one second unit being configured for rotating relative to each other around a rotation axis, with the first and the second materials rubbing against each other so as to transfer electrons from the second material to the first material and electrically charge said materials; wherein the substrate of each of the at least one first unit comprises first and second electrode members, the first electrode member comprising an outer ring integrally formed with the first electrodes legs, and the second electrode member comprising an inner ring integrally formed with the second electrodes legs, the outer ring comprising a radially outwardly extending portion forming at the periphery of the substrate a connector of the first electrode member, and one of the second electrodes legs extending radially through and out of the outer ring so as to form at the periphery of the substrate a connector of the second electrode member.

[0033] All above mentioned features disclosed in [0007]-[0028] are also disclosed in combination with the above first,and second other aspects of the invention.

Advantages of the invention

[0034] The invention is particularly interesting in that it provides regenerative means to permit the regeneration of the triboelectric metallic material that rubs against the triboelectric dielectric material. The stacked configuration allows also a compact design with an increased specific power.

Brief description of the drawings

[0035] Figure 1 is a perspective exploded view of a triboelectric generator according to the invention. [0036] Figure 2 is a top view of the rotating triboelectric disc-shaped unit of the generator of figure 1.

[0037] Figure 3 is a top view of one of the stator triboelectric disc-shaped units of the generator of figure 1.

[0038] Figure 4 is a perspective view of a stack of triboelectric disc-shaped units as illustrated in the generator of figure 1 and illustrating the connection of the electrodes.

[0039] Figure 5 is a perspective view of the stack of triboelectric disc-shaped units of figure 4, illustrating in addition auxiliary electrodes for regenerating the metallic contact surfaces of the rotating units.

[0040] Figure 6 is a front view of the stack of triboelectric disc-shaped units of figure 5.

[0041] Figure 7 is a schematic cross-sectional view of the triboelectric generator of figure 1 , illustrating two options for driving the rotating the triboelectric generator.

Description of an embodiment

[0042] Figure 1 is an exploded view of a triboelectric generator according to an embodiment of the invention. The generator 1 is built as a stack of disk- shaped units comprising at least, respectively from the bottom to the top of the stack, a carrier 2, a first unit 4 composed of a layer 4¹ of interdigitated electrodes and of a layer 4² of triboelectric material, a second unit 6 with partially metallic triboelectric material, and a second first unit 8 composed of a layer 8² of triboelectric material and a layer 8¹ of interdigitated electrodes. Both units 4 and 8 are similar or even can be identical and arranged in mirror symmetry with regard to the second unit 6. The first units 4 and 8 thereby sandwich the second unit 6.

[0043] The carrier 2 has to be non-conductive and rigid enough to hold the stack.

It can be disc-shaped with the same dimensions of the others top layers, but it can also be larger and/or show another shape. The carrier can be made of an organic or inorganic material. Preferably it can be an acrylic like material or glass, or a coating of silicon oxide materials onto Silicon wafer for example. [0044] In each of the first units 4 and 8 the electrification material layers 4² and 8² can be disposed on the layers 4¹ and 8¹ of interdigitated electrodes. Even though this is not shown in the figures, the interdigitated electrode layers 4¹ and 8¹ can be disposed on a substrate. The electrification material layers 4² and 8² include a first material that is in a first position on the triboelectric series and having the affinity to accept electrons. The first material is dielectric, such as fluorinated ethylene propylene. The interdigitated electrode layers 4¹ and 8¹ include a first electrode member (electrode 1 ) and a second electrode member (electrode 2). The first electrode member comprises legs that are interleaved with legs of the second electrode member so that a continuous radially extending gap separates the first electrode legs from the second electrode legs.

[0045] The second unit 6 comprises a patterned dielectric material coated by a thin layer of a second material taken at a second position in the triboelectric series where materials have the affinity to release electrons. The second material is metallic, preferably aluminium or copper, more preferably copper. The thickness of the coating can be comprised between 10 nm to 10 μηη, preferably 10 nm to 500 nm, more preferably between 50 to 400 nm. The patterned dielectric material is disc-shaped and defines openings evenly distributed in a concentric ways and complementary legs linked inwardly by a hub and outwardly by a rim. A hole in which an axle can be inserted is present at the centre of this patterned dielectric material.

[0046] The arrangement of the two first units of triboelectric material and the second unit of partially metallic triboelectric material defines a triboelectric active element. The second unit 6 is rotatable around the rotation axis 10 relative to the first units 4 and 8. In preferred mode, the first units 4 and 8 are stationary and the second unit 6 is rotatable. During rotation and frictional movement of the triboelectric material layer 4² and 8² against the metallic triboelectric material on both sides of the second unit 6, electrons are transferred from the metallic material to the dielectric material and an alternating voltage at each pair of neighboring legs of the first and second electrode members is thereby generated. This phenomenon as such is well known to the skilled person and does not need to be further detailed. [0047] The triboelectric metallic layer is in contact with the bottom and top triboelectric dielectric material. The contact between those material layers has be tight enough to allow the creation of triboelectric charges but the pressure and adhesion between those different layers had to allow the rotation of the metallic layer.

[0048] The triboelectric dielectric materials that sandwich the metallic triboelectric layer are taken at the same position in the triboelectric series, where materials have the affinity to "capture" electrons. Alternatively those two triboelectric dielectric materials can be taken in two different positions in the triboelectric series where materials have the affinity to "capture" electrons. Preferably the materials will be, in a non-limiting way, Polyester, Celluloid, Polystyrene, Orion, Acrylic, Polyvinylidene chloride (Saran), Polyimmine Polyurethane, Polyethylene, Polypropylene, Polyvinylchloride (Vinyl), PTFE, Silicon, and/or Teflon.

[0049] A nano- and/or micro-texturing of the surfaces of the triboelectric metallic material and or the top and bottom triboelectric dielectric materials can be done to enhance the electrical output properties of the triboelectric generator.

[0050] Figure 2 illustrates the second unit 6 defining a plurality of evenly spaced apart elongated openings 6¹ extending radially outwardly from a hub 6² to an outer ring 6³. A corresponding plurality of evenly spaced apart elongated leg portions 6⁴ extend radially outwardly from the hub 6² to the outer ring 6³. Each leg portion 6⁴ has a shape and size that corresponds to each opening 6¹. The metallic coating can cover the patterned dielectric materials only on the surfaces which are in contact with the top and bottom triboelectric dielectric materials. It can also cover the peripheral edge surface 6⁵ that is radially outwardly oriented. Alternatively the coating can be deposited on all the surfaces of the patterned dielectric materials. Alternatively the thickness and the nature of said metallic coating can be different depending on the surface of said patterned dielectric material.

[0051] Alternatively, the second unit 6 can be a totally metallic material. In that configuration the all bulk material is made of the same metal that has been patterned in the same kind of design previously described for the patterned dielectric material. Similarly, the metallic material is taken at one position in the triboelectric series where materials have the affinity to release electrons. Preferably, the material will be aluminium or copper, more preferably copper.

[0052] Figure 3 illustrates the interdigitated electrode layer 4¹ or 8¹ of one of the first units 4 and 8. The layer 4¹ or 8¹ includes a first electrode member 12 and a second electrode member 14. The first electrode member 12 includes an outer ring 12¹ and a plurality of evenly spaced apart first electrode legs 12² extending inwardly from the outer ring 12¹. The second electrode member 14 is complementary in shape to the first electrode member 12 and includes a hub or inner ring 14¹ and a plurality of evenly spaced apart second electrode legs 14² extending outwardly from the inner ring 14¹. The first electrode legs 12² are interleaved with the second electrode legs 14² so that a continuous gap separates the first electrode member 12 from the second electrode member 14. The first electrode member 12 and the second electrode member 14 are both made from a conductive material, such as gold or copper (or other materials such as a conductive metal, a conductive oxide, graphene or a conductive polymer). The interdigitated electrode layer 4¹ or 8¹ could be made from a single layer by forming the gaps using well known lithography techniques (e.g., etching, laser cutting, etc.).

[0053] Still with reference to figure 3, the first electrode member 12 can also comprise a portion 12³ extending radially outwardly from the outer ring 12¹ and serving as connector. Similarly, the second electrode member 14 can also comprise a portion 14³ extending radially outwardly from one of the second electrode legs 14² through the outer ring 12¹ of the first electrode member 12, thereby serving as connector for said second electrode member.

[0054] Figure 4 illustrates the triboelectric generator of figure 1 in a configuration where the generator 1 comprises several second units 6, for instance six second units 6. Each second unit 6 is sandwiched by two first units 4 and 8. Each first unit located between two successive second units 6 is therefore common and shared by the two second units. As is visible in figure 4, the connectors 12³ and 14³ of the first and second electrode members 12 and 14 are aligned, respectively. The connectors 12³ are electrically connected to each other by a first connecting bar 16. Similarly, the connectors 14³ are electrically connected to each other by a second connecting bar 18. This means that the first and second electrode members of the several first units are connected in parallel.

Figures 5 and 6 illustrate the triboelectric generator of figure 4 in a configuration where it comprises two auxiliary electrodes 22 and 24 for applying a regenerative current to the triboelectric material of the second units 6. Such a generation takes place in a "static mode". By static mode, it is meant a mode in which no driving force is applied to the axle 20. Consequently no rotational movement is transferred to the metallic second units. In that configuration, the auxiliary electrodes 22 and 24 are positioned to electrically contact the peripheral edge surface of the metallic material, said edge surface being radially outwardly oriented. The contact can be made at two diametrically opposed positions. Once the contact is done, a current is applied to pass through the triboelectric generator. As the only conductive parts in this triboelectric generator are the totally or partially electric triboelectric layers of the second units, the current is passing through those parts. An appropriate current is applied for achieving metal ion diffusion or electro migration. Electro migration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. This effect is important in applications where high direct current densities are used, such as in microelectronics and related structures. This effect is as such well-known. The current density and shape, thickness and/or geometry of the totally or partially metallic triboelectric layers, temperature and the already above mentioned parameters are tuned to allow the regeneration of the overused metallic triboelectric surfaces. The current density can be of at least 10mA cm². The current signal can be continuous or direct. It can also be alternating. The number of metallic layer connected per electrodes is of six in figures 5 and 6, being understood that this can be more or less depending on the number of stacks. Alternatively, between two applications of electro migration current, the second units can be rotated by a fraction of a turn. Figure 7 is a schematic cross-sectional view of the triboelectric generator of figure 1 , illustrating two options for driving the rotating the triboelectric generator. Both the axle 20 and the second unit are either one continuous material (left magnified view in figure 7) or two distinct pieces of the same or different materials (right magnified view in figure 7)). In this latter case, a rotating axle is driving the rotation of the metallic disc-shaped layer via a gear like system integrated on the axle and on the metallic layer. The axle 20 can be made of a dielectric material or a metallic material.

Claims

1. Triboelectric generator (1) comprising:

- at least one disc-shaped first unit (4, 8) including

o a substrate (4¹, 8¹), and

o a layer (4², 8²), on said substrate, of a first material being a dielectric material taken from the triboelectric series;

- at least one disc-shaped second unit (6) including a second material being a metallic material taken from the triboelectric series;

the at least one first unit (4, 8) and the at least one second unit (6) being configured for rotating relative to each other around a rotation axis (10), with the first and the second material rubbing against each other so as to transfer electrons from the second material to the first material and electrically charge said materials;

characterized in that it further comprises:

auxiliary electrodes (22, 24) configured for contacting the second material at the periphery of the at least one second unit (6) and for transmitting a regenerative current of the surface of said second material contacting the first material.

2. Triboelectric generator (1 ) according to claim 1 , characterized in that the auxiliary electrodes (22, 24) are positioned at diametrically opposed locations at the periphery of the at least one second unit (6).

3. Triboelectric generator (1 ) according to one of claims 1 and 2, characterized in that the auxiliary electrodes (22, 24) are movable between a position where they are distant from the second material and a position where they electrically contact said material.

4. Triboelectric generator (1 ) according to claim 3, characterized in that the auxiliary electrodes (22, 24) are movable in a diametrical direction of the at least one second unit.

5. Triboelectric generator (1) according to any one of claims 1 to 4, characterized in that each of the at least one second unit (6) comprises a peripheral edge surface (6⁵) that is radially outwardly oriented, the second material extending to said peripheral edge surface, so as to be contacted by the auxiliary electrodes (22, 24).

6. Triboelectric generator (1) according to any one of claims 1 to 5, characterized in that the auxiliary electrodes (22, 24) extend parallel to the rotation axis (10) or form an angle of less than 30°, preferably less than 15°, with said axis (10).

7. Triboelectric generator (1 ) according to any one of claims 1 to 6, characterized in that it further comprises an electric unit configured for applying a regenerative current to the second material through the auxiliary electrodes (22, 24).

8. Triboelectric generator (1) according to any one of claims 1 to 7, characterized in that the at least one second unit (6) extends radially outwardly beyond the at least one first unit (4, 8), so that the auxiliary electrodes (22, 24) can contact said second unit(s) (6) without contacting said first unit(s) (4, 8).

9. Triboelectric generator (1) according to any one of claims 1 to 8, characterized in that the at least one first unit comprises a pair of first units (4, 8) for each of the at least one second unit (6), said pair of first units (4, 8) sandwiching said second unit (6), the substrate (4¹, 8¹) of each of said first units (4, 8) comprising a first and second electrode members (12, 14), said first and second electrode members (12, 14) comprising a series of first and second radially extending electrodes legs (12², 14²), respectively, said first and second electrodes legs (12², 14²) being disposed in an alternating manner around the rotation axis (10).

10. Triboelectric generator (1 ) according to claim 9, characterized in that the first electrode member (12) comprises an outer ring (12¹) integrally formed with the first electrodes legs (12²), and the second electrode member (14) comprises an inner ring (14¹) integrally formed with the second electrodes legs (14²), the outer ring (12¹) comprising a radially outwardly extending portion (12³) forming at the periphery of the substrate (4¹, 8¹) a connector of the first electrode member (12), and one of the second electrodes legs (14²) extending radially through and out of the outer ring (12¹) so as to form at the periphery of the substrate (4¹, 8¹) a connector of the second electrode member (14).

1 1. Triboelectric generator (1) according to clainn 10, characterized in that the connectors (12³, 14³) of the first and second electrode members (12, 14) at the periphery of the substrate (4¹, 8¹) of each first unit (4, 8) are located within a sector centred on the rotation axis and of less than 30°, preferably less than 20°, more preferably less than 10°.

12. Triboelectric generator (1 ) according to one of claims 10 and 1 1 , characterized in that the connectors (12³) of the first electrode members (12) of the first units (4, 8) are aligned, preferably along a direction parallel to the rotation axis, and are electrically connected via a first connecting bar (16), and/or the connectors (14³) of the second electrode members (14) of the first units (4, 8) are aligned, preferably along a direction parallel to the rotation axis, and are electrically connected via a second connecting bar (18).

13. Triboelectric generator (1) according to any one of claims 1 to 12, characterized in that the second material of the at least one second unit (6) forms legs (6⁴) that extend radially with areas (6¹) between adjacent legs (6⁴) that are void of said material.

14. Triboelectric generator (1) according to any one of claims 1 to 13, characterized in that each of the at least one second unit (6) comprises a substrate with a hub (6²), an outer ring (6³) and leg portions (6⁴) radially extending between the hub (6²) and the outer ring (6³), said substrate being made of dielectric material and the second material being coated on said substrate.

15. Triboelectric generator (1 ) according to any one of claims 1 to 14, characterized in that it comprises a rotating axle (20) extending along the rotation axis (10), said axle being rotatably engaged with the at least one second unit (6), said axle (20) and second unit(s) (6) preferably comprising mutually engaging toothed profiles.

16. Method of regeneration of the contact surface(s) of a triboelectric generator (1 ), characterized said generator is in accordance with one of claims 1 to 15 and said method comprises a step of applying a regenerative current through the at least one second unit (6) via the auxiliary electrodes (22, 24) while the generator (1) is inoperative.

17. Method according to claim 16, characterized in that the step of applying a regenerative current is carried out for different angular positions of the at least one second unit (6).