Passive anti-frosting strategies based on interfacial humidity regulation: From mechanisms to applications

Frost formation in low-temperature environments causes significant efficiency losses and safety hazards across aerospace, HVAC, and manufacturing industries. Conventional active anti-frosting methods suffer from poor energy efficiency due to periodic energy input requirements. This review summarizes recent advances in passive anti-frosting through interfacial humidity regulation—a strategy that inhibits ice crystal nucleation and growth by actively controlling local water vapor, offering substantial energy-saving potential. We firstly discuss theoretical models of ice nucleation in supersaturated vapor, examining how surface energy, microstructure, and chemistry govern interfacial humidity distribution and phase transitions. Secondly, three widely reported humidity regulating media, ice, hygroscopic gels, and hygroscopic liquids, are examined in terms of their vapor regulation mechanisms and frost suppression performance. Thirdly, we address advanced anti-frosting strategies based on interfacial humidity regulation via hygroscopic materials, biological protein and inspired microstructured surfaces. This review provides theoretical foundations and technical guidance for next-generation energy-efficient frost suppression technologies.