Enhanced TENG Performance by Engineering the Compression Modulus of Triboelectric Layers

Abstract

A vertical contact-separation mode (CS-mode) triboelectric nanogenerator (TENG) was developed for energy harvesting applications. The TENG was fabricated using polytetrafluoroethylene (PTFE) and Polyimide (kapton) films as negative and positive triboelectric layers, respectively and copper tape was used as top and bottom electrodes. Polydimethylsiloxane (PDMS) was used as a support layer to reduce the compression modulus of kapton and to improve the contact stress between kapton and PTFE, resulting in an enhanced TENG output voltage. The stress, strain, and compression modulus of triboelectric layers at three different conditions: bare kapton as tribo-layer (Case-1), bare PDMS as tribo-layer (Case-2), and PDMS/kapton as tribo-layer (Case-3) were modeled using COMSOL software. The voltage generation performance of TENG (Case 1, 2, and 3) was demonstrated by investigating the open-circuit voltage (OCV) at an applied mechanical force of 5 N. A maximum OCV of 11 Vp-p was measured for TENG with PDMS as support layer and a lower compression modulus of 8 MPa when compared to the TENG without PDMS (OCV of 2 Vp-p).