Enhanced Atmospheric Water Harvesting Performance by Three-Dimensional Carbon Fiber Felt Structure

Freshwater shortages and the uneven distribution of water resources are critical issues for economic development and human life, and collecting water vapor in the air is one of the important ways to alleviate these issues. In recent years, adsorption-based atmospheric water harvesting (AWH) techniques have received much attention, and the core difficulty in establishing an efficient system is to develop a highly efficient functional material for AWH. In this work, an AWH material was prepared consisting of carbon fiber felt as a three-dimensional skeleton and loaded with poly(vinyl alcohol) immobilized LiCl and graphite, as a water capture and release functional material. A 24 h water capture–3 h water release test was carried out at room temperature, showing excellent water collection ability of 0.907 g·g–1 of water at 30% relative humidity (RH) and 2.429 g·g–1 of water at 80% RH. Using a 2 h capture–2 h release cycling test, the sample demonstrated a stable water capture–release performance. An outdoor field test was conducted, showing water collection efficiencies of up to 60%. We believe that the carbon fiber felt can provide good mechanical properties and achieve a high mass loading of the functional materials, and the composite material has a simple manufacturing process and realizes energy saving and sustainable water harvesting.