Contact Electrification at Adhesive Interface: Boosting Charge Transfer for High‐Performance Triboelectric Nanogenerators

Abstract

Charge transfer, a decisive feature for surface charge density in triboelectric nanogenerators (TENGs), differs in quantity and species at different contact interfaces. Regarded as the main electrification mechanism, electron transfer has been extensively investigated in constructing high‐performance tribo‐materials and TENGs, in which material transfer has been always neglected. Here, it is demonstrated that material transfer is a crucial electrification mechanism for adhesive polymers in contact electrification, and plays a dominant role in boosting charge transfer and TENG performance. Specifically, as a new strategy for utilizing the adhesion capability, this study introduces the stabilized poly(thioctic acid) adhesives as tribo‐materials to maximize contact electrification. With material transfer at the adhesive interface, abundant mechanoions are generated through covalent bond cleavage and higher charge density is obtained from the triboelectric pairs with larger interfacial adhesion force. Under a gentle triggering condition (5 N, 1 Hz), the TENG can achieve a high charge density of 14.65 nC∙cm−2, with a maximum output power density of 10 W∙m−2. Furthermore, the TENG exhibits unique frequency‐insensitive, pressure‐ and temperature‐enhanced output characteristics. This study provides new insight into constructing high‐performance TENGs using adhesives and highlights the indispensable role of material transfer in polymer contact electrification.

Contact Electrification at Dielectric Polymer Interfaces: On Bond Scission, Material Transfer, and Electron Transfer

“…Further, experimental measurements of transferred polymer particles have been observed by numerous groups via an array of techniques including XPS, [10,16,39] AFM, [10,16] Raman, [40] and IR spectroscopy, [40][41][42] providing strong evidence for material transfer occuring. Notably, recent work by Shi et al, [39] showed that the adhesive force during PCE directly correllated to the measured surface charge, proving mechanical interactions and bond cleavage must contribute to the observed charging phenomena.…”

Fluid-based triboelectric nanogenerators: unveiling the prolific landscape of renewable energy harvesting and beyond

“…The prevalent mode of charge transfer in CE at interfaces-whether between liquid and solid, liquid and liquid, or even gas and solid-is highly likely to be electron transfer. 44…”

Understanding contact electrification via direct covalent bond cleavage of polymer chains for ultrahigh electrostatic charge density

“…Actually, the scientific understanding of CE for triboelectric charge generation still remains ambiguous and inconclusive, particularly in the most frequently used triboelectric material-insulating polymers. 30–34 Currently it is often elucidated by the transfer of electrons, ions and materials. The electron-transfer mechanism can well explain CE between two different metals (or one metal and one semiconductor/insulator) by its good correlation of electron work function with charging.…”

“…As one of the three mainly reported mechanisms, the material-transfer mode is developed by the exchange of charged material species between the contact areas to understand CE, and the transfer of materials carrying mechanoradicals is also feasible. 33,43–45 Unfortunately, the generation reasons of electrostatic charges/mechanoradicals on the surface of transferred materials are still inexplicit. The detailed mechanisms and the extent to which material transfer specifically influences the CE process remain inadequately described.…”