Soft Human–Machine Interface with Triboelectric Patterns and Archimedes Spiral Electrodes for Enhanced Motion Detection

The rapid development of electronic skins has allowed novel multifunctional human–machine interaction interfaces, especially in motion interaction sensors. Although motion sensing is widely used in advanced flexible electronic devices through the integration of single sensing units, the number of electrodes has increased with the increase in integration by the square multiple. This paper presents a self-powered electronic skin based on the Archimedes spiral structure design, which can detect the multi-directional movement of the slider without external energy supply. As the rotation angle of the Archimedes spiral increases from 2π to 4π, the maximum resolvable movement direction of the device increases from 24 to 280, and the number of electrodes is kept at 4. Through the exploration of the principle of triboelectricity, the inherent electronegativity of the triboelectric materials is used as the basis for signal discrimination, which not only increases the reliability of the device, but also solves the problem of energy supply during device operation. A reduced number of electrodes and its battery-free nature enables this electronic skin to be easily integrated into portable electronic devices, such as laptops, smart phones, healthcare devices, etc.     

Leaf-Like TENGs for Harvesting Gentle Wind Energy at An Air Velocity as Low as 0.2 m s−1

Existing technologies for harvesting electrical energy from gentle wind face an enormous challenge due to the limitations of cut-in and rated wind speed. Here, a leaf-like triboelectric nanogenerator (LL-TENG) is proposed that uses contact electrification caused by the damped forced vibration of topology-optimized structure consisting of flexible leaf, vein bearing plate, and counterweight piece. The effectiveness of the topology-optimized leaf-like structure is studied, which solves the problem of reduced output due to electrostatic adsorption between the leaf surfaces while reducing the cut-in (0.2 m s⁻¹) and rated wind speed (2.5 m s⁻¹). The LL-TENG unit having small dimensions of 40 cm⁻² (mass of 9.7 g) at a gentle wind of 2.5 m s⁻¹ exhibits outstanding electrical performances, which produces an open-circuit voltage of 338 V, a short-circuit current of 7.9 µA and the transferred charge density of 62.5 µC m⁻² with a low resonant frequency of 4 Hz, giving an instantaneous peak power of 2 mW. A distributed power source consists of the five LL-TENGs in parallel is developed by designed self-adaptive structure, for which the peak power output reaches 3.98 mW, and its practicability and durability are successfully demonstrated. This study is a promising distributed power source technology to drive electronics in gentle wind outdoor environments.     

Liquid–Solid Triboelectric Probes for Real-Time Monitoring of Sucrose Fluid Status

Triboelectric probes have rapidly developed as an efficient tool for understanding contact electrification at liquid–solid interfaces. However, the liquid–solid electrification process is susceptible to interference from chemical components in mixed solutions, severely limiting the potential applications of triboelectric probes in various liquid environments. This study for the first time reports a triboelectric probe capable of sucrose solution concentration sensing, finding that the dissolution of sucrose destroys the hydrogen bond network between water molecules and forms sucrose–water hydrogen bonds, which alters the fluid mechanics characteristics of the solution and enhances its conductivity, thereby reducing the droplet size and causing an ion charge shielding effect that significantly affects the electron transfer in liquid–solid contact electrification. Owing to the feedback of the triboelectric probe on the sucrose concentration gradient-type sensing electrical signals, efficient sensing of sucrose solution was achieved (sensitivity of −0.0038%⁻¹, response time of 90 ms). The triboelectric probe is also used as a wireless smart terminal to enable real-time detection of sucrose solution. This work contributes to the understanding of the structure–function relationship between micro hydrogen bonding and macro performance, and provides a promising solution for building sustainable intelligent sensors.