High-Powered Superhydrophobic Pyroelectric Generator via Water Droplet Impact

Recent studies on water-based pyroelectric generators (PyGs), which convert thermal energy to electrical energy, have focused on different operational modes like water evaporation, water stream, and droplet sliding. However, the development of sustainable, high-powered generators and comprehensive theoretical models has been limited. In response, our research introduces a superhydrophobic (SHPo) PyG, exploiting the characteristics of lead magnesium niobate-lead titanate (PMN-PT) coated with titanium dioxide nanoparticles. We analyzed power density by considering the phase transient temperature that maximizes the pyroelectric coefficient of PMN-PT, testing various Weber numbers and droplet diameters within a moderate operating temperature range of 40°C to 80°C. Considering the dynamic characteristics of water droplet on SHPo surfaces, we suggest the peak current model that can accurately predicting the actual peak current. Also, the maximum power density of 54.5 μW/cm² at a droplet diameter of 3.6 mm and a PMN-PT temperature of 80°C, a noteworthy improvement over 3 times higher than previous water-based PyGs. Our results enhance the understanding of the pyroelectric effect coupled with drop impact dynamics and outlines novel strategies for designing high-performance water-based PyGs.