Hydrovoltaic Energy Harvesting From Nut Shells

Water-induced electric generators (WEGs) exhibit tremendous promise as sustainable energy sources harvesting electricity through the interaction between materials and water utilizing the hydrovoltaic effect, an innovative green energy harvesting method. However, existing water-induced electric generator devices predominantly rely on inorganic materials with limited research on naturally available, bio-based materials for hydrovoltaic energy harvesting. This study introduces a novel nutshell-based hydrovoltaic water-induced electric generator for the first time. This low-cost, organic, and efficient renewable energy source can generate a voltage above 600 mV with a power density exceeding 5.96 μW cm⁻² utilizing streaming and evaporation potential methodologies, which can be sustained for more than a week. Notably, after further chemical treatments and combining the physical and chemical phenomena, output voltage and maximum current density reach a record high of 1.21 V and 347.2 μA cm⁻² respectively, which outperforms most inorganic and organic materials-based water-induced electric generators. By connecting two units in series and parallel, this eco-friendly water-induced electric generator can power an LCD calculator without the assistance of any rectifier. We believe that this novel nutshell-based water-induced electric generator provides a significant advancement in water-induced electric generator technology by offering a sustainable solution for powering electronic devices utilizing agricultural waste.