Recent progress in energy harvesting systems for wearable technology

This paper provides a comprehensive review of the recent progress made in energy harvesting systems for wearable technology. An energy-harvesting system would be a useful strategy to address the issue of powering wearable electronic devices. This review presents different wearable energy harvesting methods based on the human body's heat and mechanical energy. To achieve continuous operation and high performance, reduce the requirement for external sources of energy, and enhance the lifespan of wearable devices, the invention of a sustainable and compatible power supply is required. In the human body, heat and mechanical motions are the two reliable and readily available energy sources. This study highlights the most recent research and advancements in energy harvesting from the human's mechanical motion and heat source. This article provides a detailed overview of the different wearable energy harvesters, their fabrication, working, and output results, which include piezoelectric, electrostatic, triboelectric, electromagnetic, thermoelectric, solar and hybrid wearable energy harvesters. The second part defines wearable energy harvesting using smart systems and artificial intelligence technology. Then the comparison of these energy harvesters is analyzed. Hybrid wearable energy harvesters provide the maximum power densities because they use two combined energy conversions. The advantages, limitations, and future perspectives of wearable energy harvesting technology are also discussed. Lastly, the wearable energy harvesters' market, and general developing and manufacturing cost of each wearable device is also presented functioning as a point of reference to comprehend the cost factors that are taken into account during the development and manufacturing processes.