Reversed vapor generation with Janus fabric evaporator and comprehensive thermal management for efficient interfacial solar distillation

Interfacial solar steam generation, with high energy efficiency, promotes the solar desalination technology to a new era. However, the problem of low freshwater yield in enclosed distillation system owing to optical loss and insufficient condensation capability remains a challenge. In this work, a reversed interfacial solar distillation system is proposed by combining Janus fabric with comprehensive thermal management to significantly enhance the freshwater yield. Recycled cotton fabric is used to fabricate the low-cost Janus fabric with carbon black@silicone on the top side via a simple and scalable pre-wet coating method. The Janus fabric with high sunlight absorbance (98.0 %) and good sealing properties remarkably guarantees the downward vapor generation to eliminate the optical loss, resulting in the improved freshwater collection of the distiller. Comprehensive thermal management is designed for the distillation system to reduce the heat loss of the evaporator and enhance the condensation effect of the condenser. The optimal Janus fabric-based interfacial solar distiller achieves an outstanding water yield of 1.17 kg m−2h−1 and an efficiency of 78 % under one sun (1 kW m−2) illumination. This work presents a novel design of a high-performance interfacial solar distillation system, offering the potential for large-scale and low-cost industrial production.