The poor ability of covalent organic frameworks (COFs) based adsorbents at low relative humidity (RH) conditions limits their applications for air-water harvesting in arid environments. In the present work, the sulfonated COFs (DAAQ-TFP-SO3H@LiCl) composites are prepared through the functionalization of sulfonic acid and LiCl composite to improve its hydrophilicity. TheDAAQ-TFP-SO3H@LiCl composites exhibit a good adsorption performance, outperforming many other COF adsorbents developed so far. It can absorb 0.22 +/- 0.005 g g-1 and 1.01 +/- 0.027 g g-1 of water at room temperature under 20% RH and 90% RH, respectively while demonstrating good cyclic stability. Compared with the isotherm of the DAAQ-TFP, the introduction of the sulfonic acid group shifts the inflection point of the water isotherm toward low humidity, indicating that the sulfonic acid group effectively expends the working humidity range of the adsorbent and enables the effective water adsorption in an arid environment. Furthermore, the DAAQ-TFP-SO3H@LiCl composites display rapid kinetics during both the adsorption and desorption processes, reaching saturation within 60 min in the equilibrium adsorption test and completing desorption within 12 min at 50 degrees C. This innovative approach provides a new method for designing adsorbent materials with low energy input requirements and high daily water consumption capabilities. The DAAQ-TFP-SO3H@LiCl composite adsorbent, produced through the processes of sulfonation and mechanical agitation exhibits enhanced hydrophilicity at low relative humidity (RH), allowing it to efficiently absorb water vapor from the air in an arid environment. When incorporated the designed air-to-water harvesting device, this composite adsorbent enables the capture of 4.15 g of liquid water over a single outdoor day. image