Sustainable moisture energy

Harvesting energy from the ambient is a promising approach to fulfil decentralized energy demands and facilitate the transition to low-carbon economy. Moisture-sorption-based energy harvesting (MSEH) is a promising strategy for obtaining heat, cold and electricity from ubiquitous moisture anywhere and anytime. Advances in water-sorption materials have promoted the development of sustainable moisture energy. However, MSEH technology faces the challenges of low-energy productivity and limited recognition of its working mechanisms and thermodynamic analysis. We centre this Perspective article around an in-depth understanding of the underlying mechanisms and thermodynamic limitations of sustainable moisture energy. We first introduce the working principles of MSEH for heat, cold and electricity generation, and summarize recent progress in water sorbents. We then discuss thermodynamic limitations and evaluate global potential for sustainable moisture energy. We outline future challenges of water-sorption kinetics and propose technical directions for accelerating water sorption-desorption with ordered cross-scale energy transfer and mass transport. Finally, we offer an overview of future research areas for water sorbents with higher water uptake, tunable water affinity and faster water sorption for next-generation high-performance MSEH. Moisture-sorption-based energy harvesting (MSEH) is a promising strategy for obtaining heat, cold and electricity from ubiquitous moisture anywhere and anytime. This Perspective article discusses the thermodynamic characteristics of MSEH, evaluates global energy production potential and highlights challenges and strategies for realizing high-energy-productivity MSEH.