Negative triboelectric polymers with ultrahigh charge density induced by ion implantation

Triboelectric polymers have attracted tremendous attention due to the fast development of triboelectric nanogenerator (TENG). However, the detailed factors determining the polarity and the intensity of the electrification in polymers are still not fully revealed. Here, we demonstrated that N-containing polar groups and unsaturated bonds can break the spatial structural symmetry of the polytetrafluoroethylene (PTFE), improve the polarity and electronegativity of groups, turn them into polar polymers, intensify the electron cloud overlap to enhance the electron-withdrawing (EW) capability, thereby accurately regulate their electrification properties. In order to improve the triboelectric performance, a different modification strategy based on ion implantation technique is reported for generating these specific bonds to achieve ultrahigh negative triboelectric polymers. The modified fluorinated polymers exhibit ultrahigh negative triboelectric polarity and their surface charge density have 4~8 times enhancements comparing with original samples. Meanwhile, stronger polarity doubles the dielectric constant and further enhances the energy storage density of the material. The physical study in this work elaborates the fundamental mechanism by which molecular structures regulate macroscopic electrical properties, which provides a guidance for manufacturing advanced triboelectric polymers through the micro-regulation of polarity.