Faradaic Reversible Electrodes Enable Programmable High-Power Hydrovoltaic Energy Harvesting Across Broad Ionic...

Area of Science:

• Materials Science
• Energy Harvesting
• Electrochemistry

Background:

• Hydrovoltaic devices offer sustainable electricity generation from water evaporation.
• Current limitations include low current density and narrow operational ionic strength ranges.

Purpose of the Study:

• To develop high-current hydrovoltaic devices operable in diverse ionic environments.
• To achieve programmable electrical outputs using novel electrode designs.

Main Methods:

• Fabrication of dual-function, mesh-structured core-shell Ag/AgX reversible electrodes.
• Utilizing in-situ formed AgX shells for ion-electron transduction and Ag cores for electron transport.
• Leveraging localized charge inversion effects for output control.

Main Results:

• Achieved a record-high current density of 26.0 µA cm⁻² sustained over 160 h with Ag/AgI electrodes and KI electrolyte.
• Demonstrated ≈260-fold higher current and ≈39-fold greater power density compared to previous systems.
• Enabled programmable electrical outputs across a wide ionic concentration window (10⁻⁶–10⁰ M) and multiple ionic species.

Conclusions:

• The developed Ag/AgX electrodes significantly enhance hydrovoltaic device performance.
• This technology enables versatile energy-sensing systems and self-powered monitoring in various water sources.
• The strategy offers a pathway to practical, high-performance hydrovoltaic energy solutions.