Triboelectric Nanogenerator Production Using Cold Spray

Abstract

Triboelectric Nanogenerators (TENGs) have been proposed as a method of converting external mechanical energy into electricity. Placing these generators in a position to passively harness enough energy to power small devices could reduce the dependence on batteries and recover energy that otherwise would be lost as heat. When two dielectric materials on opposite sides of the triboelectric series come into contact, charge transfer will occur according to the triboelectric effect: Charge will move between materials to equalize the electromechanical potential, leaving the two dielectrics oppositely charged. When the two charged dielectric layers separate, their opposite surface charges create an electric field that induces a voltage between the top and bottom electrodes, which are connected through a load. If this separation and contact motion repeats periodically, the device produces a continuous alternating current signal. Production of these generators has yet to be streamlined, and there is no current standardized production method for these devices. The Cold Spray (CS) process is proposed in this study as a method of producing a simple and low cost TENG.

CS is a coating technique where solid powder particles are accelerated in a supersonic gas stream to be deposited on a substrate. Once impacting the substrate, particles undergo plastic deformation remaining entirely in their solid state and bond to the substrate. Using CS, triboelectric materials can be deposited directly on electrodes, streamlining and allowing the scaling of the manufacturing process and building a simple and low cost TENG. Aluminum, Copper and Perfluoroalkoxy Alkane polymer powders were deposited on copper substrates acting as electrodes to produce the necessary triboelectric layers. Electrical tests were then performed at varying resistances and frequencies to determine the maximum power output. The overall and theoretical maximum conversion efficiencies were then calculated. It was found that the roughness of materials deposited with the cold spray process added to the efficacy, a promising result for industrial adoption where low frequency alternating current is needed.