Triboelectric-Nanogenerator-Based Soft Energy-Harvesting Skin Enabled by Toughly Bonded Elastomer/Hydrogel Hybrids

Abstract

A major challenge accompanying the booming next-generation soft electronics is providing correspondingly soft and sustainable power sources for driving such devices. Here, we report stretchable triboelectric nanogenerators (TENG) with dual working modes based on the soft hydrogel-elastomer hybrid as energy skins for harvesting biomechanical energies. The tough interfacial bonding between the hydrophilic hydrogel and hydrophobic elastomer, achieved by the interface modification, ensures the stable mechanical and electrical performances of the TENGs. Furthermore, the dehydration of this toughly bonded hydrogel-elastomer hybrid is significantly inhibited (the average dehydration decreases by over 73%). With PDMS as the electrification layer and hydrogel as the electrode, a stretchable, transparent (90% transmittance), and ultrathin (380 μm) single-electrode TENG was fabricated to conformally attach on human skin and deform as the body moves. The two-electrode mode TENG is capable of harvesting energy from arbitrary human motions (press, stretch, bend, and twist) to drive the self-powered electronics. This work provides a feasible technology to design soft power sources, which could potentially solve the energy issues of soft electronics.

Double‐Hydrophobic‐Coating through Quenching for Hydrogels with Strong Resistance to Both Drying and Swelling

“…Until now, only a few hydrogels have been reported that exhibit good resistance to drying or swelling . However, none of the hydrogels developed thus far have shown stability in both air and water, which limits their practical applications .…”

“…Hydrogels with drying resistance were originally developed by incorporating high‐density hygroscopic salts in the bulk hydrogel system or by encapsulating the hydrogels within an elastomeric material . However, the former may produce a toxic effect owing to the presence of high‐density salts, while the latter makes hydrogels impermeable to many important chemicals, such as ions and drug molecules, eliminating an important function of hydrogels.…”

Recent progress on flexible nanogenerators toward self‐powered systems

“…Thus, from the material point of view, the electron affinity, surface function groups, as well as work function are important factors affecting the output performance of TENG. A vast number of advanced materials have been explored, including graphene, MXenes, hydrogels, aerogels, black phosphorus (BP), etc.…”

“…Copyright 2016, Wiley‐VCH. D, TENG‐based E‐skins . Copyright 2017, The American Association for the Advancement of Science.…”

“…Meanwhile, the E‐skin sensing pressure as low as 1.3 kPa was demonstrated. Due to the easy dehydration of hydrogels, toughly bonded elastomer/hydrogel hybrids through interfacial modification to ensure the stable mechanical and electrical performance of the E‐skin device was reported by Liu et al After the tough interfacial bonding, the dehydration of the hybrids is greatly alleviated with an average dehydration decreases by over 73%. Furthermore, Wang et al reported a transparent and flexible polyionic‐skin TENG (PS‐TENG) with resistance to dehydration .…”