Externally motionless triboelectric nanogenerator based on vortex-induced rolling for omnidirectional wind energy harvesting

Wind-driven triboelectric nanogenerators (WTENGs) are an emerging technology that holds the potential for sustainable wind energy harvesting. Although recent efforts have proposed various strategies for developing WTENGs, realizing their practical utility, characterized by high output performance, lightweight design, compact dimensions, and omnidirectional energy capture, remains a formidable challenge. This study introduces an innovative WTENG that leverages a rolling-based mechanism to achieve effective omnidirectional wind energy harvesting. The distinctive design features a guide vane and a deformable rolling cylinder, both of which play pivotal roles in enhancing triboelectrification, optimizing power output, and ensuring consistent performance despite fluctuations in wind direction. Specifically, the guide vane generates a rotating flow, facilitating the rolling of the cylinder. The electrical energy is generated through triboelectrification occurring between the cylinder and the inner surface of the vane as the cylinder rolls during operation. Numerical simulations and experimental validation have underscored the critical significance of the design of the guide vane and the structural parameters of the rolling cylinder in determining the output performance of the device. Remarkably, the proposed WTENG has demonstrated a root-mean-square area power density of 89.723 mW/m2 at a wind speed of 8 m/s, thus attesting to its superior energy harvesting capabilities. Furthermore, the versatility of this device was evident as it effectively powered a wireless environmental monitoring system and functioned as a selfpowered wind speed sensor. With a mere 42 g weight, a compact footprint of 22.062 cm2, and an internal rollingbased mechanism enabling motionless operation from an external perspective, this WTENG offers substantial advantages in spatial efficiency. Consequently, it is an ideal choice for deployment in constrained environments.