LAUSR

Since the end of the last century, energy harvesting technologies have obtained prominent development as the sustainable power supplies for billions of wireless sensor nodes distributed in both the city and remote areas. Microelectromechanical system (MEMS) energy harvesters based on the energy transferring mechanisms of electrostatic effect, electromagnetic induction, and piezoelectric effect were first proposed to scavenge the vibrational energy from the ambient environment. Thereafter, the piezoelectric nanogenerator and triboelectric nanogenerator emerged as promising techniques to harvest diversified mechanical energy for addressing the energy consumption of flourishing wearable devices. Targeting for a more efficient system, multiple strategies for improving the output performance of individual energy harvesters as well as hybridized energy harvesters are extensively investigated. Merging the well-developed energy harvesters with energy storage, wireless data transmission, and other functional units, self-sustainable systems have been realized. Shortly, with the evolving AI technologies, we can foresee that the AI-assisted self-sustainable systems will also be achieved and play a vital role in the future 5 G era. In this review, we systematically introduce the evolution of energy harvesting techniques in the 5 G and IoT era, with detailed operation principles, structural designs, enhancement strategies, self-sustainable and AI-assisted system development, and our perspectives.