Embedding variable micro-capacitors in polydimethylsiloxane for enhancing output power of triboelectric nanogenerator

Polydimethylsiloxane (PDMS) is an excellent material for investigating the mechanism of triboelectricity as it can easily be used to construct various microstructures. In this study, micro-capacitors (MCs) and variable microcapacitors (VMCs) were embedded in PDMS by filling PDMS with silver nanoparticles (NPs) and constructing an internal cellular structure. The output performance of the triboelectric nanogenerators (TENGs) based on MCs@PDMS and VMCs@PDMS films was systematically investigated, with variation of the filling content of silver NPs and the pore ratio and size. The microstructure, permittivity, dielectric loss, and capacitance of the VMCs@PDMS films were well characterized. The output current of the TENG based on the VMCs@PDMS film was respectively 4.0 and 1.6 times higher than that of the TENGs based on the pure PDMS film and MCs@PDMS film, and the output power density of the former reached 6 W·m–2. This study sheds light on the physical nature of conductive nanoparticle fillings and cellular structures in dielectric triboelectric polymers.