Stretchable, Transparent, and Thermally Stable Triboelectric Nanogenerators Based on Solvent‐Free Ion‐Conducting Elastomer Electrodes

Abstract

The development of stretchable/soft electronics requires power sources that can match their stretchability. In this study, a highly stretchable, transparent, and environmentally stable triboelectric nanogenerator with ionic conductor electrodes (iTENG) is reported. The ion-conducting elastomer (ICE) electrode, together with a dielectric elastomer electrification layer, allows the ICE-iTENG to achieve a stretchability of 1036% and transmittance of 91.5%. Most importantly, the ICE is liquid solvent-free and thermally stable up to 335 °C, avoiding the dehydration-induced performance degradation of commonly used hydrogels. The ICE-iTENG shows no decrease in electrical output even after storing at 100 °C for 15 h. Biomechanical motion energies are demonstrated to be harvested by the ICE-iTENG for powering wearable electronics intermittently without extra power sources. An ICE-iTENGbased pressure sensor is also developed with sensitivity up to 2.87 kPa −1 . The stretchable ICE-iTENG overcomes the strain-induced performance degradation using percolated electrical conductors and liquid evaporationinduced degradation using ion-conducting hydrogels/ionogels, suggesting great promising applications in soft/stretchable electronics under a relatively wider temperature range.

A Mechanically Robust and Versatile Liquid‐Free Ionic Conductive Elastomer

“…[ 3,22,25 ] More recently, ionotronic diodes and transistors have been demonstrated with the use of ionic conductive elastomers that are comprised entirely of polymer networks and mobile ions and contain no liquid components, such that these devices are non‐volatile without the hassles of leaking liquid materials. [ 27 ] Thus far, the report of mechanically robust ionic conductive elastomers is still rare: [ 28 ] demonstrated liquid‐free ionic conductive elastomers exhibit limited stretchability and self‐healing capability, [ 27,29 ] incompatible with the stringent requirements of durability for soft machines and wearable electronics.…”

Progress inTENGtechnology—A journey from energy harvesting to nanoenergy and nanosystem

“…To achieve multi-functionalities, with the aid of triboelectric materials and structural designs, advanced electrode designs can also be incorporated into conventional TENGs, resulting in applicationoriented TENG configurations, that is, operating independently in the form of real-time and situ sensing. 105,226,243,[374][375][376][377][378][379][380][381][382][383][384][385][386][387][388][389][390][391][392] Toward NENS, blue energy is one of the most important application directions, which is mainly in forms of wave energy, tidal energy, and osmotic energy harvesting. To the aspect of the wearable electronics and HMI, TENG shows the potential abilities in realizing the advanced manipulation with the digital world.…”

Stretchable and Shape‐Adaptable Triboelectric Nanogenerator Based on Biocompatible Liquid Electrolyte for Biomechanical Energy Harvesting and Wearable Human–Machine Interaction

“…Moreover, most state‐of‐the‐art power devices can hardly match the biocompatibility, robustness, low cost, and flexibility or stretchability of the wearable electronics. [ 3 ] For example, owing to the materials and volume limitation, it is difficult to seamlessly integrate wearable electronics with conventional heavy and rigid batteries, which cannot bypass the repetitive recharging and replacing processes. [ 4 ] Great efforts have been devoted to develop the energy‐harvesting strategies to sustainably generate electricity from the surroundings and the flexible storage devices for wearable electronics, such as flexible solar cells, [ 5 ] thermoelectric generators, [ 6,7 ] piezoelectric nanogenerators, [ 8 ] and flexible supercapacitors /lithium‐ion batteries.…”

“…[ 9–12 ] However, the research on the highly stretchable and compatible energy devices still fall behind. [ 3,13,14 ] Therefore, it is highly desired but still challenging to realize the high stretchability, biocompatibility, and durability of energy devices, which can harvest biomechanical energy from human motion and directly power wearable electronics. [ 13,15 ]…”

“…Despite excellent stretchability of some ionic hydrogels, their long‐term instability, low mechanical toughness, and low conductivity limit their large‐scale practical application due to the dehydration or evaporation of liquid solvent. [ 3,47 ] The liquid metal (e.g., galinstan) as liquid stretchable electrode has been employed by Wen et al. to fabricate the super‐stretchable single‐electrode TENG for harvesting biomechanical energy to power portable electronic devices.…”