Freestanding-Mode Tribovoltaic Nanogenerator for Harvesting Sliding and Rotational Mechanical Energy

摘要

A series of direct-current tribovoltaic nanogenerators (TVNGs) with highcurrent density have been developed for energy harvesting and mechanicalsensing recently, but the lead wires that need to be connected to two relativelymoving parts have greatly restricted the application of TVNG. Herein,a freestanding-mode TVNG (FTVNG) is proposed based on metal, p-typesilicon (p-Si), and n-type silicon (n-Si). As the freestanding part of metalsimultaneously rubs against p-Si and n-Si, opposite direct current (DC)outputs can be generated, thus forming a DC output from p-Si to n-Si in theexternal circuit. Resulting from the distinctive structure, FTVNGs are applicablefor harvesting energy from moving objects without attached wires.Additionally, by using steel needles to precisely control the actual contactarea, the electrical output characteristics and influence laws of the tribovoltaiceffect under different working parameters such as area and speed arestudied. Moreover, FTVNG is integrated into the traditional rolling bearing asa triboelectric bearing, realizing energy recovery from the rotational motion ofmechanical parts and speed sensing, which demonstrates the great applicationpotential of TVNG in basic components and parts.