Stearic Acid-Enhanced Triboelectric Nanogenerators with High Waterproof, Output Performance, and Wear Resistance for Efficient Harvesting of Mechanical Energy and Self-Powered Sensing for Human Motion Monitoring

Abstract

Low power density and poor wear resistance seriously hinder the application of a triboelectric nanogenerator (TENG) in daily environments. However, current research has mainly focused on improving the performance of TENGs through inorganic fillers while neglecting the important property of wear resistance. Due to the excellent properties of stearic acid (SA), such as its cheap and easy availability, high electronegativity, wear resistance, hydrophobicity, and lubricity, as well as promoting the formation of electroactive β phase polyvinylidene fluoridehexafluoropropylene (PVDF-HFP), SA can be used as an organic multifunctional filler to improve the electrical output performance and wear resistance of TENG while increasing its hydrophobicity. In this work, we doped SA into polytetrafluoroethylene (PTFE)/PVDF-HFP matrix by solution casting method and template method to form SA-doped PTFE/PVDF-HFP(SA-PTFE/PVDF-HFP) composite polymer film, which were assembled with silk to form SA-TENG. Most importantly, the addition of 3 wt % SA not only increases the voltage and current of TENG by 3.7 times and 3.6 times, respectively, but also reduces the coefficient of friction and the amount of wear of TENG by 40.8 and 87.5%, respectively, and increases the hydrophobic angle by 12 to 133°, which ensures the long-term and stable operation of TENG in different environments. In addition, SA-TENG can not only harvest energy from the surrounding environment and charge portable electronic devices but can also be used as a self-powered sensor to monitor human movement. This study not only provides a feasible strategy for organic fillers to solve the bottleneck problem of TENG application but also broadens the application scenarios of TENG.

Highly Moisture-Resistant Flexible Thin-Film-Based Triboelectric Nanogenerator for Environmental Energy Harvesting and Self-Powered Tactile Sensing

“…The gradual development of renewable energy, which neither emits pollutants nor greenhouse gases, into the mainstay of the energy supply is conducive to fundamentally solving the problem of energy supply security. In recent years, energy harvesting methods using collected solar energy, tidal energy, wind energy, or human mechanical energy to convert into electricity have attracted widespread attention for low-power, small, self-powered electronic devices such as wearable devices, , detectors, and electronic skins . Among them, as a new type of energy harvester, the triboelectric nanogenerator (TENG) utilizes the coupling effect of triboelectrification and electrostatic induction to effectively harvest waste mechanical energy from the external environment and the human body, converting it into electricity to solve power supply problems for some electronic devices. − Due to its high sensitivity to mechanical stress, high electromechanical conversion efficiency, high freedom of material selection, strong applicability, and low cost, , the application of portable TENG devices has been extended to various fields, such as the human–computer interaction, self-powered sensors, and automatic force electrochemistry, etc., showing significant advantages in the application of next-generation intelligent devices.…”