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

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 & BULL;cm(-2), with a maximum output power density of 10 W & BULL;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.