Harvesting Body Motion Energy

Human’s body motion is considered as the most abundant sources for energy especially for powering wearable, implantable and personal electronics. In this chapter, TENGs designed for harvesting body motion energy are introduced, each of which has its own unique design and advantages. The earliest work is integrated rhombic structured TENGs that can be used as a self-powered backpack. And then, flexible materials such as fabrics and papers are used for developing wearable and portable TENGs. The body motion energy can also be harvested by TENGs with special structure designs, such as single-electrode (SE) TENG for conveniently utilizing human skin as one triboelectric layer, and sliding freestanding-triboelectric-layer (SFT) TENG for high efficient energy harvesting. These TENGs will open new opportunities of developing wearable and portable TENG-based self-powered systems. In the last two decades, the popular usage of cell phone based personal electronics is fast growing and it is reaching every corner of our life for the purpose of health monitoring, behavior sensing and security. With the drastic drop in energy consumption of the small electronic devices, it is feasible to use the energy harvested from body motion for power small electronic devices. However, body motion is irregular both in amplitude and frequency. Especially, body motion is in the range of low-frequency of sub-10 Hz or sub Hz. Therefore, efforts have been devoted to harvest mechanical energy from body motion since the invention of TENG. For body motion energy harvesting, the TENGs used include traditional integrated structure based TENGs and paper based TENGs and sliding freestanding-triboelectric-layer mode TENGs (SFT). This chapter is to systematically introduce these approaches.