Ultrahigh power output and durable flexible all-polymer triboelectric nanogenerators enabled by rational surface engineering

Abstract

Triboelectric nanogenerators (TENGs) open up a new field of sustainable energy harvesting and can specifically satisfy the growing demand for self-powered electronics. For practical applications of TENGs in self-powered wearable electronics, apart from their output performance and stability, other aspects such as mechanical robustness and scalability to large areas are crucial. In this regard, here we present a promising strategy to enhance the performance and stability of flexible all-polymer TENGs via rational surface engineering, which involves using cationic poly-L-lysine (cPLL) and 1H,1H,2H,2H-perfluorodecyl (F₁₇) fluorosilane polymer as a surface modification layer for a highly-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) electrode and polydimethylsiloxane (PDMS) dielectric layers, respectively. Our results indicate that both PLL and F₁₇ polymer films can effectively modulate the work-function (WF) values of triboelectric layers as a result of the formation of surface dipoles, thereby facilitating the generation of triboelectric charges. Additionally, the presence of interaction at the PDMS/F₁₇ polymer and PEDOT:PSS/cPLL interfaces can alleviate the adhesion issue between layers. With these appealing advantages, the resulting TENG delivers an open circuit voltage (V_oc) of 688 V and short circuit current (I_sc) of 33.0 μA, which are much superior to those of the TENG without modification layers. In particular, a remarkable power output with a power density of 13.4 W m⁻² and specific power of 95.3 mW g⁻¹ are attained for our flexible TENG, enabling it to light up 122 light emitting diodes and charge commercial capacitors quickly. To the best of our knowledge, the power output achieved in this study sets a new record for TENG technology. More encouragingly, such a TENG also possess excellent durability, revealing almost negligible degradation in I_sc and V_oc after 200 000 cycles of continuous operation under ambient conditions. This work provides a promising strategy for enhancing the performance and durability of flexible TENGs based on scalable cost-effective manufacturing, which is expected to inspire next-generation wearable energy harvesting technology.