Piezoelectric DC Generator Through Sequential In-Phase Polarization Variation

Energy harvesting has drawn growing interest as a reliable power source for IoT applications, with piezoelectric materials notable for their high sensitivity and straightforward integration. Their robust mechanical-electrical coupling also makes them ideal for harnessing environmental vibrations or mechanical motions. Still, standard piezoelectric harvesters inherently produce alternating current (AC), necessitating complex rectification steps and leading to substantial energy loss. This work introduces a direct current (DC) harvesting method that employs a novel in-phase polarization strategy, enabling a stable, continuous DC output. This approach surpasses prior attempts that offered only low or pulsed DC signals, achieving an open-circuit voltage of 33.44 V and a short-circuit current of 3.72 mA with a size of 7.5 cm². A prototype generator demonstrated a maximum power output of 29.73 mW. Moreover, this design is both miniaturizable and scalable, broadening its potential deployment across diverse sectors. Its practical value was exemplified by directly powering CO₂ electrolysis, where it achieveds a Faradaic efficiency of 86.22%, underscoring the method's ability to circumvent AC-based inefficiencies and pave the way for more effective, sustainable energy solutions.