A scalable wood-based interfacial evaporator assisted with localized joule heating for round-the-clock operations

Abstract

The evaporation efficiency of solar-driven interfacial steam is significantly affected by the diurnal variations in solar irradiance and is further compressed by the absence of light. This work proposes a wood-based interfacial evaporator with an auxiliary heat mode to achieve round-the-clock operations. The device was constructed using sustainable, cost-effective in-situ Ni-P electroless plating followed by hole drilling and surface graphite spray-coating. The self-floating evaporator achieves an evaporation rate of 2.20 kg m⁻²h⁻¹ under 1 Sun illumination and 2 V input in 3.5 wt% NaCl solution. The realized rate can be attributed to the localized interfacial heat induced by the electroless-plated Ni-P alloy (R_sheet = 1.45 Ω/sq). Moreover, adopting the novel hierarchical advantages, including mesoporous nature, low anisotropic thermal conductivity of wood, and reduced evaporation enthalpy in Ni-P film (1893 J/g), the device further reaches a daytime evaporation yield of 8.47kg m⁻² on cloudy days and 14.68 kg m⁻² on sunny days, respectively. And a yield of 5.33 kg m⁻² with an electrical energy input of ∼ 0.71 kW m⁻² is recorded during nighttime. This performance implies a significant step towards wood-based evaporators for round-the-clock water harvesting and shows potential for upscaling devices to all-weather 3D evaporators.