Robust Solid‐Liquid Triboelectric Nanogenerators: Mechanisms, Strategies and Applications

Abstract

Solid‐liquid triboelectric nanogenerators (SL‐TENGs) are a new technology that combines contact electrification (CE) and electrostatic induction to collect clean energy stored in natural water. Considering their unique advantages of high energy density, wide selection of materials and being suitable for large‐scale promotion, they have attracted more and more attention in recent years, and numerous studies have shown their great potential in various applications. Many critical applications of SL‐TENGs inevitably involve sustained and stable high electrical output. To achieve stable output performance and long cycle life in these applications, the adaptability of SL‐TENGs to material selection, structural design, and working environment is necessary. Therefore, the construction of SL‐TENGs matching different applications has become a critical research direction in TENGs. This review provides a historical summary of the development of SL‐TENGs in the past few years and analyzes the key factors affecting their electrical output performance. The exciting achievements of different constructions of SL‐TENGs for practical applications is also demonstrated such as energy harvesting, self‐powered sensing, and self‐powered cathodic protection. Finally, the development prospects of SL‐TENGs and the significant challenges for their further development is discussed.

Water droplet energy harvesting

“…[78][79][80][81][82][83][84] Among them, lots of liquid-based TENGs with various structures and materials are proposed to achieve an outstanding performance of droplet energy harvesting. [85][86][87][88][89][90][91] When the interface contact happens between liquid and solid phases, the CE process occurs at the solid-liquid interface instantly. Generally, the charges will be transferred between the materials and then reach a dynamic equilibrium state.…”

“…Ever since invented in 2012, the TENG relying on the coupling effect of contact electrification (CE) and electrostatic induction, has witnessed great progress and achievements in mechanical energy harvesting and self‐powered sensor systems (Figure 2a). 78–84 Among them, lots of liquid‐based TENGs with various structures and materials are proposed to achieve an outstanding performance of droplet energy harvesting 85–91 . When the interface contact happens between liquid and solid phases, the CE process occurs at the solid–liquid interface instantly.…”

Insulating Electrets Converted from Organic Semiconductor for High‐Performance Transistors, Memories, and Artificial Synapses

“…The resulting oxygen‐degraded C 8 ‐PTCDI (D) features deep traps, with more trap density and deep trap energy levels. This property is useful not only for transistors, memories, and artificial synapses, [ 5 ] but also for other electret‐based devices such as energy harvesting, [ 6 ] logic operation and data encryption, [ 7 ] high response piezoelectric elastomers, [ 8 ] air‐permeable vibrotactile actuators, [ 9 ] liquid‐solid‐based triboelectric nanogenerators, [ 10 ] smart active sensing. [ 11 ]…”

Humidity‐Resistant Triboelectric Nanogenerator Based on a Swelling‐Resistant and Antiwear PAN/PVA‐CaCl2 Composite Film for Seawater Desalination

“…[ 6–8 ] The TENG is capable of converting mechanical energy from various sources, in nature and daily life, into usable electrical power by leveraging the coupling effect of contact electrification (CE) and electrostatic induction. [ 9–12 ] The TENG has been widely applied in high‐efficiency energy conversion and self‐powered electrochemical systems, including air pollution cleaning, [ 13–15 ] degradation of organic pollutants, [ 16–18 ] collection of heavy metal ions, [ 19–21 ] and water treatments. [ 22–24 ] However, under high relative humidity (RH) conditions, atmospheric moisture adsorbed on the surface of the TENG triboelectric layer accelerates the triboelectric charge transport and dissipation, [ 25,26 ] thereby substantially reducing the output performance and stability of the TENG and limiting its practical applicability.…”