Energy Harvesting with Fiber based Triboelectric Laminates for Wearable Devices

Triboelectric nanogenerators (TENG) are intriguing energy harvesting devices that convert mechanical energy into electricity and could power small portable devices or charge batteries [1]. Herein, we develop a broad and scalable approach to introduce volumetric dipoles into TENGs and break the surface charge paradigm by generating layer-by-layer triboelectric laminate structures from sequential electrospinning of large and small polymer fibers. When large fibers are electrospun onto smaller fibers, the interface between the laminate layers will slip, leading to internal contact electrification. In contrast, when small fibers are electrospun onto large fibers, they form an interpenetrated network with tight binding, creating a nonslip interface. This combination of ordered interfaces leads to parallel dipole moments being formed within the bulk volume of the laminate leading to an effective macroscopic dipole being formed. Increasing the total number of layers within a laminate, of the same total volume, leads to a linear relationship between charge and layer number. Most importantly we demonstrate that this concept not only works for laminates made of 2 different polymers but from identical polymer as well. We also show that exploiting triboelectric laminates in TENG devices can enhance their current output by 40 times. We believe that this concept will be widely used in the future for designing wearable devices with low power demand.<br/><br/>[1] Z.L. Wang “Triboelectric Nanogenerators as New Energy Technology for Self-Powered Systems and as Active Mechanical and Chemical Sensors”, ACS Nano 7 (2013) 9533-9557.