Cylindrical Direct‐Current Triboelectric Nanogenerator with Constant Output Current

Abstract

In this article, a cylindrical direct‐current triboelectric nanogenerator (DC‐TENG) that can generate an almost constant current output with a low crest factor by phase coupling is reported for the first time. Here, the influence of phases (P) and groups (G) on the DC‐TENG is investigated. Experiments show that the crest factor of current, significantly decreases as the phases increase, and the output performance significantly increases as the groups increase. One phase triboelectric power‐generating unit of the DC‐TENG with three‐phase and five‐group (3P5G) produces an open‐circuit voltage of 149.5 V, short‐circuit current 7.3 μA, and transferred charge of 56.7 nC at 600 rpm. The DC‐TENG can produce a coupling current of 21.6 μA and the average output power of 2.04 mW after each phase output is rectified and superimposed. Additionally, the crest factor of output current is reduced to 1.08, and the high‐performance characteristics of an almost constant direct‐current is achieved. The research is of considerable significance to the practical applications of TENGs in powering sensors of low consumption.

Triboelectric nanogenerator: from alternating current to direct current

“…Given that most electronics work at a constant current condition, the development of DC output or even constant current output power source has obvious advantages for the miniaturization of self-powered systems and the high efficiency of energy storage ( Li et al., 2020b ; Liu et al., 2019a , 2020b ; Zhou et al., 2020a ). Some methods have been reported to realize DC output arising from electrostatic induction, such as mechanical rectifier and phase control ( Kim et al., 2018 ; Li et al., 2020c ; Qiao et al., 2021 ; Ryu et al., 2018 ; Wang et al., 2020b ; Zhang et al., 2014 ). Furthermore, breakdown effect is innovatively used for restricting the direction of electron transfer and shows particularly characteristics of simple structure and high energy conversion efficiency ( Liu et al., 2019a ).…”

“…Compared with AC-TENG, DC-TENG has unique merits of direct current characteristics to drive electronics without any rectifier or even energy storage unit, and thus shows great potential for practical applications. Up to now, strategies such as rotary rectifier bridge ( Kim et al., 2018 ; Qiao et al., 2021 ; Zhang et al., 2014 ), double-wheel design ( Yang et al., 2014 ), multiphase rotation-type structure ( Kim et al., 2018 ; Li et al., 2020c ; Qiao et al., 2021 ; Ryu et al., 2018 ; Wang et al., 2020b ), contact-separation-type structure ( Dharmasena et al., 2020 ), and electrostatic breakdown effect ( Liu et al., 2019a ; Luo et al., 2018 ; Yang et al., 2014 ) have been used for realizing DC output in TENG. Exploring the full potential of TENG from new structures and even new principle to realize DC output is highly desired for accelerating the miniaturization of IoTs and self-powered systems and may promote the understanding of TENG from a new horizon.…”

Direct Current Triboelectric Nanogenerators

“…To overcome this issue, DC-TENG with phase coupling was proposed where a constant DC output can be obtained. [86,88,93,94] A cylindrical multiphase DC-TENG reported by Wang et al, [88] (Figure 2a) consisting of a rotator with fluorinated ethylene propylene film (FEP, as negative triboelectric material) and a cylindrical stator with separated copper foils (as both the electrodes and the positive triboelectric material). The multiphase DC-TENG is composed of TENGs with three different phases (the initial angle of electrodes is different) and each phase of TENG consists of three groups of Cu foils in parallel (Figure 2b).…”

“…[93] In short, the key to attain constant DC output through phase coupling is to enable each TENG power generation unit for producing the current signal with phase difference via specific design structure. [86,88,93,94] Ryu et al [86] realized phase shifting of current signal with the segmentation of electrodes. The DC-TENG consists of a rotator made of polytetrafluoroethylene (PTFE) and mono cast (MC) nylon and a stator made of PTFE with segmented Cu electrodes ( Figure 2i).…”

“…The insulator-based DC-TENGs will result in high internal impedance (MΩ), [88,96] which is much higher than that of the ordinary electronic devices and sensors. [90] In order to achieve a DC output with low impedance, semiconductor-based DC-TENGs without any additional rectification methods have been introduced.…”