A review of phononic-crystal-based energy harvesters

Energy harvesting is a technique in which ambient energy is converted to useful energy to prevent wastefulness. Piezoelectric energy harvesting is described as conversion of mechanical energy into electrical energy. Vibrations, sounds, ocean motions, human activities, etc. are various nature sources of mechanical waves. Energy harvesting is used to directly power electronics or recharge a battery. Efficiency is the important parameter of an energy harvester. To achieve high electrical energy harvesting from mechanical waves, phononic crystals have been utilized. Phononic crystals are a type of metamaterial that can manipulate the propagation of mechanical waves. Researchers have proposed different techniques to concentrate acoustic waves in phononic crystals. In this paper, a comprehensive review of phononic-crystal-based energy-harvesting techniques has been conducted. An energy-harvesting capability comparison between proposed phononic-crystal-based energy harvesters is also included.