Harnessing dual forms of water energy for all-weather high-performance electricity generation using amorphous slurry†

Harvesting ubiquitous water energy through hydrovoltaic technology offers a promising avenue for clean energy and has attracted significant interest. However, current hydrovoltaic systems are plagued by their reliance on a single form of water, which limits their current density to below 5 μA cm⁻² when humidity deviates from the optimal level. Here we present a dual-mode water-driven electricity generator (DWEG) that utilizes amorphous slurry to harvest energy from both moisture and liquid water through absorption and evaporation modes, respectively. Leveraging the efficient ion diffusion driven by water gradients at high humidity and the hydration free-energy difference at low relative humidity, this design achieves a current density above 144 μA cm⁻² across 5 to 90% relative humidity, and maintains a voltage of 0.7 V for over 420 hours at 90% relative humidity. We demonstrate that DWEG arrays can be readily scaled up to directly power desk lamps for more than five days, or even charge a tablet computer with an aluminum electrode. This work opens a route towards efficient energy harvesting from multiple forms of water energy under all-weather conditions.