Boosted energy harvesting in droplet electrochemical cell with non-equilibrium electrical double layer

Droplet energy harvesting technologies, such as droplet triboelectric nanogenerators (D-TENGs) and droplet-based electricity generators (DEGs), which are not restricted by geographical location, have been vigorously developed in recent years. However, achieving electricity generation with high performance is still challenging. Here, we demonstrate a new approach for droplet-based energy harvesting device named droplet electrochemical cell (DECC) which could enhance energy generation performance by utilizing the formation of non-equilibrium electrical double layers. The DECC is designed by drawing inspiration from the zinc-copper primary battery system and demonstrated remarkable results when tested with dynamically impinging water droplets. The peak current and transferred charge generated by a 100 μL droplet are found to be 400 μA and 3.2 μC, respectively. The short circuit current is also found to increase by approximately 30 times when the dynamic impinging frequency of the droplets is increased. This study provides valuable insights into the development of energy harvesting devices based on droplets.