**2. Different working mechanisms of triboelectric nanogenerators (TENGs)**

Generally, TENGs produced energy by contact electrification through the coupling effect of two oppositely charged materials. While contact electrification, the dissimilar materials becomes charged after contacting each other and generate opposites triboelectric charge from the surface of two dissimilar materials with different electron affinities. When the external mechanical motion is driven, the materials were separated resulted in the potential difference between the two opposite electrodes on the backside of the resource materials. To continue the electrostatic equilibrium, the free electrons from the electrodes were flown in the external circuit to balance the induced potential difference, consequently, the mechanical energy converted into electrical energy.

Depending on the different construction strategies of potential electrodes which show four different modes of TENGs have been constructed, as explained as follows.

#### **2.1 Vertical contact-separation style**

The mechanistic approach of vertical contact-separation mode is described typically by an example. The simplest construction of TENG includes two metal

**143**

**Figure 1.**

*3D Ionic Networked Hydrophilic-Hydrophobic Nano Channeled Triboelectric Nanogenerators*

electrodes, and dielectric surface, in which two Aluminum layers work as a top electrode and bottom electrode attached to a dielectric film, respectively [21, 22]. When the mechanical system is vertically functions, the top electrode and dielectric film will be contacted each other, and therefore, the dielectric layer and electrode become positively charged, and negatively charged, respectively, owing to the triboelectrification. Once they were separated by a small detachment, the potential difference among the two electrodes could be convinced, which drive electrons to flow from the posterior-electrode to the top-electrode, subsequent in a pulse current with an external circuit coupled. If the two electrodes are brought into exchange again, the electrons will be flown back, and the current will be upturned

The basic construction of TENG in lateral sliding mode is the same as vertical contact-separation mode, but the difference is the top electrode will be moved over the bottom surface electrode as shown in **Figure 1b**. Next, the top electrode, and dielectric surface are fully overlap, and intimate interaction with each other, prominent to the oppositely charged surfaces. With the top electrode descending outward, the contact surface-area is gradually decreased until the wide-ranging departure of two surfaces. The departed surface will create a potential difference across the two TENG electrodes that generate a current movement from the upper electrode to the lower electrode. When the electrode moves backward, then there is reversed current flow to equilibrium the potential variance [23, 24]. The four fundamental methods of triboelectric nanogenerators: (a) vertical contact departure style, (b) in-plane contact-descending style, (c) single-electrode style, and (d) free standing triboelec-

The single-electrode mode TENG shows a bottom electrode is connected with the ground and the top surface is connected to the upper surface to get charged

*The four basic triboelectric nanogenerator styles: (a) vertical contact- departure style, (b) in-plane contact-*

*descending style, (c) single electrode style, and (d) free-standing triboelectric-layer style.*

*DOI: http://dx.doi.org/10.5772/intechopen.95324*

(**Figure 1a**)**.**

tric layer style.

**2.3 Single-electrode style**

**2.2 Lateral-sliding style**

*3D Ionic Networked Hydrophilic-Hydrophobic Nano Channeled Triboelectric Nanogenerators DOI: http://dx.doi.org/10.5772/intechopen.95324*

electrodes, and dielectric surface, in which two Aluminum layers work as a top electrode and bottom electrode attached to a dielectric film, respectively [21, 22]. When the mechanical system is vertically functions, the top electrode and dielectric film will be contacted each other, and therefore, the dielectric layer and electrode become positively charged, and negatively charged, respectively, owing to the triboelectrification. Once they were separated by a small detachment, the potential difference among the two electrodes could be convinced, which drive electrons to flow from the posterior-electrode to the top-electrode, subsequent in a pulse current with an external circuit coupled. If the two electrodes are brought into exchange again, the electrons will be flown back, and the current will be upturned (**Figure 1a**)**.**

## **2.2 Lateral-sliding style**

*Novel Nanomaterials*

**1. Introduction**

another material upon contact [20].

energy converted into electrical energy.

**2.1 Vertical contact-separation style**

**(TENGs)**

The urbanization process is quickening in the recent past due to speedy economic development and population growth in megalopolises considerably leads to the upsurge of resource demand, especially energy. Energy demand is gradually rising due to global warming and ecological degradation to overcome Technologists/ academic scientists who are considering potential substitute energies that can desperately exchange the traditional sources for example solar, wind, and tidal energies, etc. [1–4]. Numerous kinds of energy harvesting methods were developed for accumulating energies which are thermoelectric, electromagnetic devices piezoelectric, photoelectric, electrostatic, and triboelectric devices [5, 6]. On the other hand, more robust, eco-friendly, economically viable, miniature and easy to handle, and highly reproducible energy harvesting systems with advanced technologies are desirable to satisfy the tight requirement of manufacturing demand. The energy produced from mechanical devices is a common renewable energy resource that is achieved using various modes such as humanoid motion, including the body's pulsation, and rotation, etc. [7, 8]. Freshly, triboelectric nanogenerators (TEGs) have received worldwide attention for the collecting of feasible green energy from ambient resources. Classical TEGs were designed and established based on a combination of synthetic polymers for contact and separation electrification, and electrostatic induction for generating mechanical energy [9, 10]. The appropriate choice of triboelectric paired polymers and their coherent design can upsurge the rate of energy collection and conversion efficiency [11, 12]. The oppositely charged material surfaces when they contact each other at regular intervals, consequently, the ions or electrons should be motivated to flow over the external load and, create a continuous voltage, and currents, respectively. Whiteside et al. and others have studied the ion-transfer technique by integrating ionic functional groups on the solid surface such as polystyrene (PS), glass, and silicone to produce ionic electrets on the active surface [13–19]. Microspheres with internal cross-linking's that contain mobile ions and counter ions which transfer some of them in the air through

**2. Different working mechanisms of triboelectric nanogenerators** 

Generally, TENGs produced energy by contact electrification through the coupling effect of two oppositely charged materials. While contact electrification, the dissimilar materials becomes charged after contacting each other and generate opposites triboelectric charge from the surface of two dissimilar materials with different electron affinities. When the external mechanical motion is driven, the materials were separated resulted in the potential difference between the two opposite electrodes on the backside of the resource materials. To continue the electrostatic equilibrium, the free electrons from the electrodes were flown in the external circuit to balance the induced potential difference, consequently, the mechanical

Depending on the different construction strategies of potential electrodes which show four different modes of TENGs have been constructed, as explained as follows.

The mechanistic approach of vertical contact-separation mode is described typically by an example. The simplest construction of TENG includes two metal

**142**

The basic construction of TENG in lateral sliding mode is the same as vertical contact-separation mode, but the difference is the top electrode will be moved over the bottom surface electrode as shown in **Figure 1b**. Next, the top electrode, and dielectric surface are fully overlap, and intimate interaction with each other, prominent to the oppositely charged surfaces. With the top electrode descending outward, the contact surface-area is gradually decreased until the wide-ranging departure of two surfaces. The departed surface will create a potential difference across the two TENG electrodes that generate a current movement from the upper electrode to the lower electrode. When the electrode moves backward, then there is reversed current flow to equilibrium the potential variance [23, 24]. The four fundamental methods of triboelectric nanogenerators: (a) vertical contact departure style, (b) in-plane contact-descending style, (c) single-electrode style, and (d) free standing triboelectric layer style.

#### **2.3 Single-electrode style**

The single-electrode mode TENG shows a bottom electrode is connected with the ground and the top surface is connected to the upper surface to get charged

#### **Figure 1.**

*The four basic triboelectric nanogenerator styles: (a) vertical contact- departure style, (b) in-plane contactdescending style, (c) single electrode style, and (d) free-standing triboelectric-layer style.*

then the triboelectric effect is triggered as shown in **Figure 1c**. While approaching and leaving the top surface, the generated electric field is distributed through charged surfaces when they change. Then, the change in potential difference occurs between the bottom electrode and the ground. Subsequently, electrons can exchange between them to maintain the potential change [25, 26].
