Study of Energy Harvesters for Wearable Devices

Energy harvesting was and still an important point of research. Batteries have been utilized for a long time, but they are now not compatible with the downsizing of technology. Also, their need to be recharged and changed periodically is not very desirable, therefore over the years energy harvesting from the environment and the human body have been investigated. Three energy harvesting methods which are the Piezoelectric energy harvesters, the Enzymatic Biofuel cells, and Triboelectric nanogenerators (TENGs) are being discussed in the paper. Although Biofuel cells have been investigated for a long time, they are still not ready to be used in implantable biomedical devices due to their challenges and low power densities. The Piezoelectric method has been employed in many applications due to their easy fabrication techniques and the know-how of their design is familiar. TENGs are very promising energy harvesters as they can be fabricated using different materials and are considered low-cost devices.