Liquid Metal–Integrated Polyimide Nanofibers for High-Temperature Triboelectric Energy Harvesting

Triboelectric nanogenerators (TENGs) capable of operating at elevated temperatures remain constrained by charge dissipation and the poor thermal stability of conventional polymer dielectrics. Here, liquid metal (LM)-integrated polyimide (PI) nanofibers are developed as a thermally robust triboelectric platform for harsh-environment energy harvesting. Gallium-based LM nanospheres are incorporated into electrospun PI nanofibers through a sonication-assisted dispersion strategy, producing uniform composite membranes while preserving the fibrous architecture. Structural and surface analyses reveal that LM incorporation drastically modulates the local electrostatic environment of the fibers, consistent with enhanced interfacial polarization and charge trapping. Among the investigated formulations, the membrane containing 5 wt% LM delivers the optimal ambient triboelectric output, achieving an open-circuit voltage ( V oc ) of 8.40 V, improved capacitor charging behavior, and stable operation over 10,000 cycles. Under elevated-temperature testing, the output exhibited a positive temperature dependence, reaching a maximum V oc of 11.76 V at 200 °C before declining at higher temperatures, while measurable output was sustained up to 300 °C.