Energy harvesting technology based on moisture-responsive actuators

Abstract

Water contains enormous amounts of energy yet to be fully utilized. Although humans have been able to extract energy from liquid water, gaseous moisture is often regarded as an underutilized resource. Compared with liquid water, gaseous water is in a higher energy state and well worth exploring. The emergence of moisture-responsive materials provides a viable solution for the development of moisture-based energy harvesting technologies. This paper systematically reviews the recent research progress of moisture-responsive actuators (MRAs) based on different materials and discusses their deformation mechanisms in detail, including bending deformation, torsional deformation, and telescopic deformation. Additionally, various moisture-driven generators (MDGs) based on MRAs are detailed, including their energy conversion pathways and power production performances. Finally, the technical challenges to the future research of energy conversion technology based on MRAs are discussed.