Triboelectric nanogenerators (TENGs) are suitable devices for converting small mechanical movements into electrical power. TENGs are inexpensive, easy to manufacture, and have a wide range of uses, but their energy efficiency is low for use in commercial products. In this study, sepiolite doped polyacrylonitrile (PAN) and ethyl cellulose/Polyvinylpyrrolidone nanofibers are tested as negative and positive dielectric layers, respectively, to improve output performance of TENGs. In the experiments, spring assisted TENG was employed to obtain higher power density and electrospun technique was used to produce flexible nanofiber dielectrics. According to the results, different sepiolite contents (1, 3, and 5 wt%) increase tribo-potential of PAN nanofiber by expanding the surface area and dielectric constant of the dielectric layers. The optimized electrical performance are 486 V open circuit voltage and 45 mW (28.125 W/m(2)) maximum power density for 3 wt% sepiolite doped PAN nanofiber. The proposed nanofibers can be efficiently used as the dielectric layers of contact mode TENGs to supply self-powered electronic devices.