Triboelectric Balls as Three-Dimensional Vibrational Energy Harvesters and Self-Powered Sensors

Ball shaped structure, due to its 3D symmetricity, provides unique advantages in applications of energy harvesting from diverse energy sources and sensing of complicated physical motions. In this work, we integrate the ball shaped structure with triboelectric mechanism as a platform for large variety of energy harvesting and self-powered sensing applications. Two different types of triboelectric nanogenerator ball (TENG-Ball) with encapsulated steel ball or water as the movable mass are proposed and investigated. Both devices are capable of harvesting energy from various ambient energy sources, such as multi-direction vibration, spinning, rotation, rolling, and human motions, etc. The steel ball based TENG-Ball is first characterized as self-powered multi-axis acceleration and rotation sensor, and then further demonstrated for human activity monitoring and gesture recognition applications. The water based TENG-Ball, due to its robustness even in water environment, is characterized as water wave energy harvester and self-powered fishing sensor on water surface.