Triboelectric-material-pairs selection for direct-current triboelectric nanogenerators

Direct-current triboelectric nanogenerator (DC-TENG) arising from electrostatic breakdown exhibits unique merits over conventional alternating-current TENGs, such as the constant-current output and high output charge density. The selection of appropriate triboelectric material pair (TMP) is important for improving its performance. Here, we propose a universal strategy for the TMP selection of DC-TENG by simultaneously considering the friction, dielectric and triboelectric performance. Based on assessing five basic parameters in DC-TENG, including the friction coefficient, surface charge density, leakage current, breakdown charge density and breakdown efficiency, it is found that the thermoplastic urethanes (TPU)-ethylene-tetra-fluoro-ethylene (ETFE) pair presents considerable output performance. Finally, a micro-structured DC-TENG with a designed power-management circuit was fabricated to further demonstrate the enhanced performance of DC-TENG with TPU-ETFE as the TMP. This work provides an effective strategy to select appropriate TMPs to optimize the performance of DC-TENG, facilitating its practical applications.