Photogenerated Carrier Reconstructed Ion Concentration Gradients for Moisture Electricity Generators

Although moisture electricity generators (MEG), which enable conversion of atmospheric moisture into electricity, have attracted great attention, the long-term moisture absorption of MEG leads to the saturation of ion concentration gradient and the decreased ion migration rate, seriously reducing the output performance. In this work, this bottleneck of MEG is addressed by constructing a photon moisture electricity generator (P-MEG) with a photosensitive layer electrode, and the synergistic coupling of photovoltaic and hydrovoltaic effects is realized. The photogenerated carriers in photosensitive layer convert H⁺ on the photosensitive layer into H₂, resulting in a reconstructed H⁺ concentration gradient between the two electrodes of P-MEG. The direct detection of H₂ by gas chromatography and the increase of the pH from 0.26 to 2.11 under illumination both prove the H⁺ gradient reconstruction mechanism. The results show that under 80% relative humidity (RH), the illumination increases the P-MEG output voltage from 0.55 to 0.65 V the current density from 17.5 to 34.5 µA cm^-2, and the power density from 8.26 to 26.7 µW cm^-2. Present work provides a strategy to enhance the long-term stability of MEG devices.