A Stretchable Multimode Triboelectric Nanogenerator for Energy Harvesting and Self‐Powered Sensing

Abstract

that can constantly convert energy from the ambient environment into electricity. Various methods that scavenge ambient energy in different forms (solar, electromagnetic, mechanical, thermal, and so forth) have been explored through photoelectric, electromagnetic, electrostatic, piezoelectric, triboelectric, thermoelectric, and pyroelectric transduction mechanisms at different scales. [4] Among them, harvesting the most ubiquitous and constantly available mechanical energy with triboelectric nanogenerators (TENGs) has been proven to be a highly efficient, [5] cost-effective, [6] and robust approach. [7] Such devices offer lightweight, good scalability, and a wide choice of materials [8] and designs. [9] These devices have particular applicability when high mechanical flexibility and stretchability are demanded, such as for powering stretchable electronics. [10] A TENG operates based on the conjunction of triboelectrification (contact electrification) and electrostatic induction, with the former providing static surface charges and the latter transforming the displacement of charged surface and/or spatial redistribution of surface charges into electricity. [11] This unique working principle renders the TENG not only a natural choice for energy harvesting [12] but also a promising approach for active sensing. [9] Since the invention of the first TENG in 2012, [13] TENGs with various material selections, structural designs, [9] and working modes (vertical contact-separation mode, lateral sliding mode, single-electrode mode, and freestanding triboelectric-layer mode) [14] have been developed to accommodate energy conversion from different types of mechanical motions, enhance output performance as micro-/nanopower source, and extend applications as self-powered sensors. [9,12,[14][15][16] Tactile touch sensors, [17,18] acoustic sensors, [19,20] motion and acceleration sensors, [21,22] chemical sensors, [23,24] strain sensors, [25] and temperature sensors [26] have been successfully demonstrated. In recent years, a new direction that pursues the shape adaptability and stretchability of TENGs has emerged and grown rapidly, driven by the potential applications in wearable/implantable electronics, [27] electronic skin, [28] epidermal electronics, [29] and human-machine interfacing (HMI) [30] for internet of things. An ideal shape-adaptive and stretchable TENG would have the following features, along with sufficient power output. First, the key components of the TENG (including triboelectrification A new type of stretchable triboelectric nanogenerator (TENG) made of a custom-formulated stretchable conductive composite and an elastomer is reported in this work. The unique structural design allows this stretchable TENG to effectively operate in both pressing and stretching modes. In the pressing mode, the stretchable TENG is able to deliver an open-circuit voltage of 69 V, a short-circuit current density of 3.05 mA m −2 , and a power density of 23 mW m −2 under loaded conditions. The excellent electrical properties of the st...

Eco-Friendly Triboelectric Material Based on Natural Rubber and Activated Carbon from Human Hair

“…The highest power density of 242 mW/m 2 was achieved at the matched load resistance of 10 MΩ, which was almost three times higher than that of the plain NR TENG (92 mW/m 2 ). In addition, the power density reported in this work was larger than that of other biodegradable TENGs, such as bacterial nanocellulose TENGs (4.8 mW/m 2 ) [ 49 ], wood-based TENGs (57 mW/m 2 ) [ 13 ], chitosan TENGs (15.7 mW/m 2 ) [ 50 ], and the stretchable TENGs made from a conductive composite and an elastomer (23 mW/m 2 ) [ 51 ].…”

Engineering the Comfort‐of‐Wear for Next Generation Wearables

“…TENGs and PENGs can simultaneously act as sensors and power supplies, simplifying the total system. [ 102,113 ]…”

A Low‐Cost Simple Sliding Triboelectric Nanogenerator for Harvesting Energy from Human Activities

“…[17,[25][26][27][28][29][30][31][32][33][34] Only very few are responsive to mechanical stretching. [24,[35][36][37][38][39][40][41][42] Meanwhile, these sporadically reported stretching-induced electrical outputs are low, at most on the order of tens of microwatts, [24,[35][36][37][38][39][40][41][42] and hardly meet the needs for wearable and portable electronics that require mW-W level of power. [43] A possible alternative approach for passively harnessing the reciprocating motions associated with human activities is to use LS-TENGs.…”