How the optimal configuration of electrodes on a hydrovoltaic device changes with water conditions

Abstract

The rapidly growing field of hydrovoltaic power generation is focused on the production of devices capable of generating power from natural water processes. A wide variety of materials have been explored and applied in hydrovoltaic devices for ever-increasing power outputs, but most reported devices follow a similar design ‘blueprint’, and the influence of the structure and connection of electrodes remains largely unexplored. In this work, we demonstrate that the optimal configuration of electrodes on a hydrovoltaic device changes depending on the conductivity of the active material and on the characteristics of the water in which power is generated. Under most circumstances, including in ionic solutions, high power outputs are best achieved by using a two-electrode system with disconnected electrodes and a highly conductive active electrode optimized for the hydrovoltaic effect. When ionic strength of the aqueous medium is very low, however, power outputs are best achieved by using a less conductive hydrovoltaic film and directly connecting it to both electrodes. A better understanding of the relationships between electrode designs, water conditions, and active materials is essential for realizing the real-world application of hydrovoltaic devices for power generation.