Abstract: To address the challenge of low-frequency vibration energy harvesting, this paper proposes a sliding-impact bistable triboelectric energy harvester (SI-BTEH) that combines sliding and impact modes for harvesting low-frequency vibration energy. The design concept and working principle of the SI-BTEH are introduced, and its electromechanical coupling model is established. Using the Runge-Kutta numerical method, the model is solved to analyze the mechanical and electrical characteristics of the SI-BTEH, and the interaction between its electrical output and nonlinear dynamics is explored. The effect of the proof mass on the performance of the SI-BTEH is studied, revealing the mechanism for broadening the high-efficiency energy harvesting frequency band. Moreover, the experimental validation and the application demonstration are conducted. The results show that when the SI-BTEH undergoes interwell oscillation, it can conver low-frequency vibration into electricity efficiently, achieving a maximum peak output power of 0.191 mW at 13 Hz. Reducing the proof mass can effectively broaden the effective energy harvesting band. The SI-BTEH can also successfully power LED arrays and temperature/humidity sensors, indicating its potential for smart sensing and structural health monitoring.