A High‐Performance Bidirectional Direct Current TENG by Triboelectrification of Two Dielectrics and Local Corona Discharge

Abstract

According to the output mode, TENGs can be classified into four categories: i) Mechanical rectification DC TENG (coupling CE and electrostatic induction) [8,9] ; ii) constant DC TENG (Coupling CE and air breakdown) [10,11] ; iii) ordinary AC TENG (coupling CE and electrostatic induction) [12,13] ; iv) inverting AC TENG (Coupling CE with air breakdown). [14] Besides, TENGs can convert ambient mechanical energy from rain, [15,16] wind, [17,18] water flow, [19,20] and body motion [21,22] , etc. into electrical energy at relatively low frequency, so it has superiority to electromagnetic generators in the specific low-frequency mechanical energy harvesting field. [23][24][25] With structure flexibility, TENG can be integrated with other research fields in practical applications, for example, electrocatalysis, [26] biosensing, [27] autoclaving, [28] high-voltage application, [29][30][31][32] artificial intelligence, [3,14] environmental monitoring, [33] which greatly exhibits TENG properties in adjustability, compatibility and high efficiency. [34][35][36][37] The application capability of TENGs is determined by the electric energy output density per cycle, which largely depends on the surface charge density originating from the contact electrification effect. For this reason, many strategies are carried out to boost TENG output charge density, such as vacuum environment, [38] temperature [37] difference, [13] surface modification, [39] and hydrophobic treatment, [40] , etc. Recently, charge excitation methods have achieved a 3.53 mC m −2 output charge density by self-polarization of polar high-k material in charge excitation process. [41] Similarly, the optimal output charge of Miura folding-based TENG has been elevated 4.61 times with the charge excitation strategy. [42] Space-accumulation effect is an effective method for the sliding TENG, which can make 2.3 times improvement compared with the normal sliding TENG in ambient conditions. [43] Nevertheless, the output of TENG based on the coupling of CE and electrostatic induction is still limited by air-breakdown. [35] Solving the problem of air breakdown would be one of the effective ways for TENG to achieve the higher output. After increasing electrodes to 50 units, Wang, et al. achieve an output charge density of 8.80 mC m -2 and an average power density of 0.2 W m -2 for the DC-TENG Triboelectric nanogenerators (TENGs) are regarded as a promising technology to convert ambient low-frequency mechanical energy into electricity for distributed power supply. Although TENGs based on triboelectrification (TE) of metal-dielectric and air breakdown have the advantage of direct current (DC) output, the unidirectional and single-channel output mode limits their energy utilization efficiency. Here, a bidirectional and double-channel (BDC-TENG) based on TE of dielectric-dielectric and local corona discharge is proposed. Different from traditional DC-TENGs, the TE process of the BDC-TENG occurs in two dielectrics, and the double-channel output is generated from simultaneous dis...

Self-Powered, Long-Durable, and Highly Selective Oil–Solid Triboelectric Nanogenerator for Energy Harvesting and Intelligent Monitoring

“…1g and S2). The voltage output of the FO-TENG (18)(19)(20) is strongly reduced when the TENG in contact with the 100 ppm water-contaminated oil as shown in Fig. 4d, which is caused by water adsorption and wetting on the FO-TENG (18-20) (Fig.…”

“…The O-TENG modified with different amounts of Fc(x) and Fs(y) is noted as FO-TENG(x-y). For example, one modified by 18 g Fc and then deposited in 20 mg Fs air is noted as FO-TENG (18)(19)(20). The O-TENGs based on a commercial dielectric material (PI or/and PTFE) and an Al electrode are also prepared for comparison (noted as Pure Al, PI/Al, PTFE/Al and PTFE/PI/Al).…”

“…1g and S2 that the wetting behavior of FO-TENG is greatly influenced by Fc. The FO-TENG achieves superoleophobic properties when the added Fc is more than 1 g, e.g., the FO-TENG (18)(19)(20) has an oil contact angle (CA) of 167°. In contrast, the PI and PTFE surfaces are oleophilic with oil contact angles of 53° and 58°, respectively (Fig.…”

“…The sensitivity of these O-TENGs is too low to monitor the intrusive water in oils. For our as-designed O-TENG, the FO-TENG (18)(19)(20) has a good hydrophilicity (Figs. 1g and S2).…”

“…The most commercialized portable power sources, batteries, are relatively heavy and face critical lifetime limitations when they are small or flexible [14,15], and they cannot fulfill the requirement of Big Data and Internet of Things in the coming Industry 4.0 [16]. Triboelectric nanogenerator (TENG), firstly invented in 2012 [17], has attracted worldwide interests due to its simple structure and easy preparation from various commercial materials [18,19]. It has become a promising technology for energy harvesting and for constructing self-powered sensor systems via utilization of environmental mechanical energy [20][21][22][23].…”