Simultaneously Enhancing Power Density and Durability of Sliding‐Mode Triboelectric Nanogenerator via Interface Liquid Lubrication

The sliding‐mode triboelectric nanogenerator (TENG) exhibits higher charge transfer efficiency for extracting mechanical energy than the contact–separation mode TENG, but the energy loss induced by air breakdown as well as the inferior durability seriously limits its practical applications. Here, an effective strategy via interface liquid lubrication is proposed for enhancing output performance of both sliding‐mode alternative current TENG (AC‐TENG) and direct current TENG (DC‐TENG). Due to the improved breakdown field strength requirement and reduced electrostatic field strength in the microgap between the triboelectric layer and electrode, interface liquid lubrication suppresses the interfacial electrostatic breakdown and reduces charge loss after the triboelectrification process, and thus more electrostatic charges are harvested by the AC‐TENG via electrostatic induction and the DC‐TENG via electrostatic breakdown. The maximum output power density of the lubricated sliding‐mode TENG is enhanced by more than 50% (3.45 W m−2 Hz−1) compared to the device without lubrication, and shows excellent durability over more than 500 000 operation cycles. This work provides an effective approach to improve the electric performance and durability of sliding‐mode AC‐TENG and DC‐TENG, which further promotes the practical applications of TENGs. A universal method of interface liquid lubrication is proposed to improve output performance for both sliding‐mode alternative current and direct current triboelectric nanogenerators through suppressing electrostatic charge loss induced by interfacial electrostatic breakdown and promoting charge accumulation, thus achieving a 1.5‐fold improvement (3.45 W m−2 Hz−1) over normal device and excellent output durability after more than 500 000 cycles.