Origami Solar Interfacial Evaporator for Water-Electricity Co-Generation

Water scarcity represents a critical challenge to global sustainable development. While solar interfacial evaporation offers an eco-friendly approach to desalination, its widespread application has been limited by the high cost of materials, energy inefficiency in 2D evaporators, and complex fabrication for 3D evaporators. In addition, the streaming potential generated during evaporation remains largely untapped in existing systems. To address these limitations, we present an integrated water-electricity co-generator based on low-cost activated carbon fiber felt (ACFF). The planar ACFF achieves evaporation rates of 0.67-1.80 kg m^-2 h^-1 under solar intensities from 0.5 to 1.5 sun, while delivering electrical outputs of 0.50-0.60 V and 6.90-34.55 µA cm^-2. Through origami structuring that enhances light trapping and ion transport, performance is elevated to 0.76-1.93 kg m^-2 h^-1 and 0.52-0.61 V with 8.65-68.77 µA cm^-2, representing a 7.22%-14.50% improvement in solar evaporation rate and a 99.72% increase in maximum power output. The origami ACFF system not only rivals state-of-the-art 3D evaporators in performance but also provides exceptional advantages in scalability, cost, and ease of fabrication, while simultaneously generating substantial electricity. This work provides an efficient and scalable strategy toward integrated water-energy sustainability.