Boosting Output Performance of Polydimethylsiloxane-Based Triple-Layered Triboelectric Nanogenerator via Rational Design of Intermediate Layers

Over the last decade, intensive research has been conducted to enhance the performance of triboelectric nanogenerators (TENG) using intermediate layers. The underlying principle involves enhancing electrostatic induction between the triboelectric charges generated on the friction layer and the induced charges on the electrode by incorporating a charge storage layer (CSL) and a charge transport layer (CTL). In contrast to previous studies that primarily focused on improving contact electrification by introducing additives into the friction layer, relatively few investigations have systematically explored the modulation of the electrical properties of each intermediate layer through the incorporation of additives. In this study, we rationally designed a polydimethylsiloxane (PDMS)-based triple-layered TENG (PT-TENG) to enhance the output performance. The PT-TENG is composed of three layers: a CSL consisting of BaTiO₃ (BTO) nanoparticles embedded in a PDMS matrix; a CTL containing a composite of carbon nanotubes and silver nanowires dispersed in PDMS; and a friction layer made of pure PDMS. Compared to a conventional PDMS-based single-layered TENG, the PT-TENG incorporating optimized CSL and CTL exhibited a substantial enhancement in output charge density, increasing from 57.8 to 192.0 μC/m². To enhance the polarization of BTO nanoparticles in the CSL, high-voltage poling was applied to the CSL, which further increased the output charge density to 334.6 μC/m². This improvement is attributed to the synergistic effects of the enhanced charge-trapping capability of the highly polarized CSL and the efficient charge transfer facilitated by the dual conductive pathways in the CTL. This study presents an effective strategy for optimizing the intermediate layers in TENGs by carefully analyzing the electrical properties of each layer, significantly improving the output charge density and demonstrating applicability to small electronic devices that operate under momentarily external mechanical stimuli.