An open thermo-electrochemical cell enabled by interfacial evaporation

Abstract

This work explores an alternative approach to generate electric energy from a solar-driven interfacial water evaporation system. A thermo-electrochemical redox couple was combined with an evaporation system to take advantage of the temperature difference between the air–liquid interface and the bulk solution of water. An open thermo-electrochemical cell (TEC) was demonstrated to achieve the parallel processes of clean water generation and also electricity generation. Both deionized (DI) water and seawater (from the East China Sea) were used for the preparation of the electrolyte of the TEC system. Under one-sun illumination, the peak output electric power of the TEC with the seawater-based electrolyte was ∼0.5 mW m⁻². The electric output of the TEC with the solution of seawater still reached ∼2.3 × 10⁻² mW m⁻² even without solar illumination due to the temperature difference generated by natural evaporation, which provides a possibility for electricity generation at night. The TECs can also be connected in series to increase the output voltage to charge capacitors or power LEDs, as demonstrated in the work.