Advanced Materials, 2023

Abstract: 

Atmospheric water is ubiquitous on Earth and extensively participates in the natural water cycle through evaporation and condensation. This process involves tremendous energy exchange with the environment, but very little of the energy has so far been harnessed. The recently emerged hydrovoltaic technology, especially moisture-induced electricity, has shown great potential in harvesting energy from atmospheric water and gives birth to moisture energy harvesting devices. The device performance, especially the long-term operational capacity, has been significantly enhanced over the past few years. Further development, however, requires in-depth understanding of mechanisms, innovative materials, and ingenious system designs. In this review, beginning with describing the basic properties of water, we discuss the key aspects of the water-hygroscopic material interactions and mechanisms of power generation. We then summarize the current material systems and advances in promising material development. Aiming at the chief bottlenecks of limited operational time, we list advanced system designs that are helpful to improve device performance. Especially, the synergistic effect of moisture adsorption and water evaporation on material and system levels to accomplish sustained electricity generation is discussed. Finally, we analyze the remaining challenges and suggest future directions for developing this promising technology.

Link:  https://doi.org/10.1002/adma.202211165