Tribo-Elevator: Boosting the Power Efficiency of Hybrid Energy Harvesting System

While vibrational energy is abundant in environment, its intermittent and dynamic nature poses challenges to harvest as a stable power source. Hybrid energy harvesting systems offer a potential solution, yet the inherent disparity between different energy sources complicates power management, resulting in a combined output that is substantially lower than the sum of individual outputs (“1$+$1 ≪ 2”). This work introduces a novel concept of Tribo-Elevator, supported by a tailored power management strategy and circuit architecture, which achieves a hybrid output exceeding the sum of individual contributions (“1$+$1$\boldsymbol{\gt}$2”). The approach leverages a triboelectric nanogenerator (TENG) to harvest vibrational energy while exploiting its time-varying capacitance as a charge “elevator”. During each vibrational cycle, energy from other sources is boosted and injected into the TENG at its maximum capacitance (“lowest floor”), then released to the load at minimum capacitance (“highest floor”), thereby amplifying the total harvested energy. A hybrid power management circuit integrating synchronous electric charge extraction and self-boosting-injection structures is developed to implement this strategy. As a proof of concept, a TENG (for vibrational energy) and thermoelectric generator (TEG, for thermal energy) are combined, demonstrating a 138% power enhancement compared with their standalone operation.