Ultracompact Ball Vibrating Triboelectric Nanogenerator for Maximizing Instantaneous Power Output in Minimized Size

The increased adoption of Internet of Things (IOT)-based portable devices has called attention to the need for high-output portable power supply. Portable electronics powered by batteries require additional processes, such as replacement or recharging, for continuous operation. Small-sized triboelectric nanogenerators (TENGs), which have been investigated for real-time power supply, are limited by low output owing to their small surface area and small surface charge. Therefore, a TENG device that can generate a high output for a real-time power supply is necessary. Herein, an ultracompact ball-vibrating TENG (UBV-TENG) is reported. With output enhancement owing to the electron avalanche effect, the UBV-TENG can generate an instantaneous peak power of up to 0.7126 W with a diameter of 5 mm and height of 20 mm. With comparing existing TENGs, the UBV-TENG generated more than 3 times higher instantaneous peak power with smaller device size. Owing to its small size and high performance, the optimized UBV-TENG can be easily utilized for portable human-motion energy-harvesting device, such as a self-powered safety light, as demonstrated by fabricating a 2 cm × 2 cm self-powered light emitting diode (LED) circuit that powers up to 120 LEDs with stacked structures.